POSTER - 19th International Conference on Magnetism

Poster Monday 

PA01 

<strong>POSTER</strong> 

Magnetoelectric polarization in the field-induced commensurate phase 

of Y-hexaferrite Ba 0.7Sr 1.3Zn 2(Fe 1-xAl x) 12O 22 

Hak Bong Lee, Hun Chang, Young Sang Song, Jae-ho Chung 

Department of Physics, Korea Univ., Korea 

Hexagonal ferrites containing Fe 3+ (S = 5/2) ions are attracting much attention 

because it is expected that solutions for high-temperature low-field multiferroics 

can be found in these materials. Y-type Ba 0.7Sr 1.3Zn 2Fe 12O 22 possesses proper-screw 

antiferromagnetic order in zero field, which does not allow spin-current ferroelectric 

polarization. Electric polarization can, however, be induced when a strong external 

field is applied perpendicular to its c axis. The field-response can greatly be improved 

upon Al doping, which is ascribed to the formation of conical spin structures. In this 

work, we investigated the magnetic phase transitions of single crystal Ba 0.7Sr 1.3Zn 2(Fe 1xAl 

x) 12O 22 (x = 0.04 & x = 0.08) in external magnetic field. Both samples exhibited 

incommensurate helical antiferromagnetic order in zero-field cooling down to 10 K. 

When the external magnetic field was applied so that electric polarization was induced, 

however, the incommensurate order was replaced by a commensurate order in all 

samples. Our analysis shows that the commensurate order plays the role of breaking 

inversion symmetry, thereby allowing finite electric polarization. We argue that two 

different magnetic anisotropies, easy-axis and easy-plane, play an important role in 

establishing stable field-induced electric polarization in the observed commensurate 

magnetic phase. 

PA02 

Temperature- and field-tuning of magnetic phases in multiferroic 

NdFe 3(BO 3) 4 

Christie S. Nelson 1 *, Leonard N. Bezmaternykh 2 and Irina A. Gudim 2 

1 Photon Sciences Directorate, Brookhaven National Laboratory, USA 

2 L.V. Kirensky Institute of Physics, Siberian Branch of RAS, Russia 

We report the low-temperature coexistence of magnetic phases in NdFe 3(BO 3) 4, which 

is a field-induced multiferroic material. The ground state incommensurate magnetic 

phase coexists with a strained commensurate magnetic phase that is primarily at the 

surface of the crystal. Increasing the temperature or magnetic field decreases the 

incommensurability and stabilizes the commensurate magnetic phase above T ic ≈ 14 

K or H ic = 0.9 T. A comparison to published studies indicates the onset of longitudinal 

magnetostriction and electric polarization at the field-induced transition, which may 

arise due to a basal plane spin-flop and canting of moments along the field direction. 

Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was 

supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy 

Sciences, under Contract No. DE-AC02-98CH10886. 

PA03 

Control of magnetic anisotropies for stable electric polarization in 

multiferroics hexaferrites 

Hun Chang, Hak-bong Lee, Young-sang Song and Jae-ho Chung* 

Department of phsics, Korea Univ., Korea 

Hexaferrites are widely studied for the hopes of realizing multiferroics working at 

room temperature and under low field. It was shown recently that Al-doping can 

effectively enhance magnetoelectric susceptibility and low-field behaviors of Y-type 

hexaferrite Ba 0.5Sr 1.5Zn 2Fe 12O 22. The key for such enhancement has been suspected 

to be the formation of heliconical spin ordering via reduction of planar anisotropy. 

Using single crystal neutron diffraction, we investigated in detail the Al-doping 

dependence of the magnetic phase transitions in Ba 0.7Sr 1.3Zn 2(Fe 1-xAl x) 12O 22. We 

confirm that the heliconical phases indeed appear upon Al doping, and finally collapse 

into commensurate phases at excessive doping concentrations. The observed evolution 

of magnetic order coincides with the doping dependence of the magnetoelectricity 

previously reported. Analysis of magnetic energy shows, however, that planar 

anisotropy alone will not allow the heliconical order to stabilize. We argue that it is 

important to have a competition between easy-axis and easy-plane anisotropies in order 

to stabilize the heliconical order, and thereby establish the optimum magnetoelectric 

property. 

2 The 19 th <strong>International</strong> <strong>Conference</strong> on Magnetism 

PA04 

Chemical control of ferroelectric polarization in Mn1-xCoxWO4 Young-sang Song 1 , Jae-ho Chung 1 *, Sung-beak Kim 2 , Jurg Scheffer 3 , Li Qin Yan 4 , 

Bumsung Lee 4 , Sae-hwan Chun 4 , Kee Hoon Kim 4 , A. Nogami 5 and T. Katsufuji 5 

1 

Department of Physics, Korea University, Seoul, 136-713, Korea 

2 

Advancement for College Education Center, Konyang University, Chungnam 320- 

711, Korea 

3 

Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen, Switzerland 

4 

Department of Physics, Seoul National University, Seoul, 151-742, Korea 

5 

Department of Physics, Waseda University, Tokyo 169-8555, Japan 

MnWO 4 is one of the best known magnetoelectric multiferroics, in which ferroelectric 

polarization appears due to long-range spin order. Whereas it exhibits three different 

antiferromagnetic phases at low temperatures, ferroelectric polarization along the b 

axis is observed only in the intermediate phase with an elliptical spiral incommensurate 

spin structure. In this work, we present the effect of Co doping on the magnetic phase 

transitions and multiferroics properties of Mn 1-xCo xWO 4 using neutron diffraction, 

magnetization and ferroelectric measurements. The main results include the 

stabilization of the incommensurate phase at x ~ 0.03 and the flop of its spiral plane for 

x > 0.05. Subsequently, the ferroelectric polarization appears mainly along the a axis 

in this range. These results indicate that the multiferroics properties of MnWO 4 can be 

controlled via Co doping. 

PA05 

Multiferroic phase competition in orthorhombic RMnO 3: Monte Carlo 

approaches 

Jun-ming Liu* 

Department of Physics, Nanjing University, China 

For type-II multiferroic oxide compounds, the ferroelectricity is believed to be 

induced by specific spin orders which can break the spatial inversion symmetry, 

allowing an electric polarization to respond significantly to external magnetic field. 

These phenomena have been receiving attentions due to the underlying physics and 

promising application potentials. Nevertheless, conventional understanding of these 

multiferroics remains in an early stage since these materials exhibit typical features 

of strongly correlated electron systems in which the spin, charge, orbit, and phonon 

degrees of freedom are intrinsically coupled together. So far, rare models other than 

the Mochizuki-Furukawa (M-F) model specifically addressing orthorhombic RMnO 3 

are available. In this talk, we present our Monte Carlo simulations on the multiferroic 

behaviors of orthorhombic RMnO 3, based on this model. Our simulations address the 

phase competition between the ab-plane spiral spin order and bc-plane spiral spin order 

as well as their coexistence, including the following cases: (1) nonmagnetic Mn-site 

substitution; (2) R-site substitution; (3) interaction between multiferroic RMnO 3 thin 

films and magnetic substrates. We will further extend our simulation based on the semiquantum 

two-orbit double exchange model to the above issues. 

PA06 

Spin-driven electric polarization in akermanite Sr 2MSi 2O 7 crystals 

Mitsuru Akaki 1 *, Tomoya Tadokoro 1 , Takumi Kihara 2 , Masashi Tokunaga 2 and Hideki 

Kuwahara 1 

1 Department of Physics, Sophia University, Japan 

2 The Institute for Solid State Physics, The University of Tokyo, Japan 

Since the magnetoelectric effect was observed in akermanite Ca 2CoSi 2O 7 [1] and Ba 2CoGe 2O 7 [2,3], 

the multiferroicity in these materials has been attracting much attention. The akermanite materials 

show the magnetic-field-induced electric polarization which can be explained by the transition-metalligand 

(p-d) hybridization depending on the spin direction [4]. The multiferroicity of akermanite 

materials is, therefore, expected to be influenced by substitution on the transition-metal site. In this 

study, we have investigated magnetic and dielectric properties of akermanite Sr 2MSi 2O 7 (M: transitionmetal 

ion) single crystals. In Sr 2CoSi 2O 7, the electric polarization was not observed in a zero magnetic 

field. By applying the magnetic field along the [110] direction, the electric polarization emerges along 

the c axis below the magnetic transition temperature. According to the p-d hybridization mechanism, 

the electric polarization is proportional to the spin quantum number S. However, the induced electric 

polarization in Sr 2MnSi 2O 7 (Mn 2+ : S=5/2) is almost two orders of magnitude smaller than that of 

Sr 2CoSi 2O 7 (Co 2+ : S=3/2). These results suggest that the electronic configuration of the transition-metal 

ion is of crucial importance for the appearance of electric polarization. We will also present and discuss 

the results of the comparative study of magnetoelectric properties in other Sr 2MSi 2O 7 crystals. 

[1] M. Akaki et al., Appl. Phys. Lett. 94, 212904 (2009). [2] H. T. Yi et al., Appl. Phys. Lett. 92, 

212904 (2008). [3] H. Murakawa et al., Phys. Rev. Lett. 105, 137202 (2010). [4] T. Arima, J. Phys. 

Soc. Jpn. 76, 073702 (2007).

PA07 

Magnetoelectric effects in antiferromagnet Ba 2CoGe 2O 7 

Shin Miyahara 1 and Nobuo Furukawa 2 

1 JST ERATO-MF, Japan 

2 JST ERATO-MF, Aoyama Gakuin University, Japan 

We have investigated magnetoelectric effects in Ba 2CoGe 2O 7, which is a quasi two- 

dimensional antiferromagnet[1]. By applying the external magnetic field along certain 

directions, electric polarization is induced[2,3]. We consider a spin-dependent d-p 

hybridization mechanism[4], where the electric polarization couples to a single spin 

structure via the spin-orbit interaction, and we can explain the novel magnetoelectric 

behaviors in Ba 2CoGe 2O 7[3]. In this compound, it is recently reported that there 

exist magnetic excitations induced by electric components of electromagnetic wave 

at THz frequencies[5]. In addition, the magneto-electric excitation in Ba 2CoGe 2O 7 

accompanies a non-reciprocal linear directional dichroism, where absorption 

coefficient depends on the direction of the incident electromagnetic wave (+k or 

-k). We theoretically clarify the origin of the peculiar features in these dynamical 

magnetoelectric phenomena[6]. The non-reciprocal dichroism observed in Ba 2CoGe 2O 7 

can be explained by cross-correlated effects, i.e., the interference between the magnetic 

and the electric responses. 

[1] A. Zheludev et al., Phys. Rev. B 68 024428 (2003). [2] H.T. Yi et al., Appl. Phys. Lett 92 212904 

(2008). [3] H. Murakawa et al., Phys. Rev. Lett. 105 137202 (2010) [4] T. Arima, J. Phys. Soc. Jpn. 

76 073702 (2007). [5] I. Kezsmrki et al., Phys. Rev. Lett. 106 057403 (2011) [6] S. Miyahara and N. 

Furukawa, J. Phys. Soc. Jpn 80 073708 (2011) 

PA08 

X-ray non-reciprocal effects in multiferroic single crystal of GaFeO 3 

Andrei Rogalev*, Fabrice Wilhelm and Alexei Bosak 

European Synchrotron Radiation Facility, France 

Ferroelectric and ferrimagnetic ordering coexist in gallium ferrate - GaFeO 3. The 

multiferroic properties of this compound have been extensively studied since early 

sixties by many different experimental techniques. In order to study these properties 

on a microscopic level we have measured various X-ray reciprocal and non-reciprocal 

dichroisms at the Fe K-edge. The results of these experiments carried out at the ESRF 

beamline ID12 on a high quality untwined single crystal of GaFeO 3 are presented here. 

X-ray magnetochiral dichroism and X-ray non-reciprocal magnetic linear dichroism, 

which are a direct measure of the Fe orbital anapole and higher order magnetoelectric 

multipole, are disentangled experimentally for the first time. These two dichroic signals 

are compared to usual X-ray magnetic circular dichroism which is a measure of orbital 

magnetic moment carried by Fe atoms. Moreover, X-ray natural circular dichroism has 

been also measured on this biaxial non-enantiomorphous crystal. All these dichroisms 

are analyzed with the help of a set of the sum rules. This analysis allowed us to deduce 

the expectation values of different effective operators related to multiferroic properties 

of GaFeO 3. 

PA09 

NMR study on Ba0.5Sr1.5Zn2(Fe0.92Al0.08) 12O22 Sangil Kwon 1 , Soonchil Lee 1 *, Dong Young Yoon 1 , Sae Hwan Chun 2 , Yi Sheng Chai 2 , 

Kee Hoon Kim 2 , Euna Jo 1 , Changsoo Kim 1 and Byeongki Kang 1 

1 

Department of Physics, Korea Advanced Institute of Science and Technology, 

Daejeon 305-701, Korea 

2 

CeNSCMR, Department of Physics and Astronomy, Seoul National University, Seoul 

151-747, Korea 

We did zero-field NMR study on the annealed single crystal of multiferroic helimagnets 

Ba 0.5Sr 1.5Zn 2(Fe 0.92Al 0.08) 12O 22 (Al-BSZFO). This material shows extremely high 

magnetoelectric susceptibility so that the critical field for switching electric polarization 

is less than 1 mT below 90 K [1]. NMR frequency change by the temperature follows 

Bloch’s T3/2 law which presents the low temperature excitation is ferromagnetic spin 

wave. The nuclear spin-lattice relaxation rate and the nuclear spin-spin relaxation 

rate were also measured. Both increased rapidly as the temperature increases above 

60 K at which the spin structure changes from normal longitudinal cones (NLCs) to 

alternating longitudinal cones (ALCs) for the case of as-grown (not annealed) sample 

[2]. Due to rapid shortening of spin-spin relaxation time, the NMR signal intensity 

abruptly reduced above 60 K. We also studied rf pulse width and power dependence 

and revealed that most of the signal came from the domain walls. 

[1] S. H. Chun et al., Phys. Rev. Lett. 104, 037204 (2010). [2] H. B. Lee et al., Phys. 

Rev. B 83, 144425 (2011). 

PA10 


Magnetic ordering in multiferroic TbFexMn 2-xO 5 with x=0.18 

Nadir Aliouane 1 , Andrey Malyuk 2 and Dimitri N. Argyriou 3 

1 Laboratory for Neutron scattering, Paul scherrer Institut CH-5232, Villigen-PSI, Switzerland 

2 IFW Dresden, Institute for Solid State Research Helmholtzstr. 20 DE-01069 Dresden, Germany 

3 Science Directorate, European Spallation Source ESS AB P.O Box 176, SE-221 00 Lund, 

Sweden 

Manganite compounds present a large range of functional properties from colossal magnetoresitor to 

multiferroicproperties. TbMn 2O 5 is well known multiferroic materials that exhibit complex magnetic phase 

transitions [1] and multifunctional properties which are tunable by a magnetic field [2,3]. Below 38K, the long 

range incommensurate anti-ferromagnetic ordering induces the ferroelectric behavior through either an exchange 

striction mechanism between neighboring spins wave (Si.Sj≠0) [4] or inverse Dzyaloshinskii-Moriya interaction 

due to cycloidal spin arrangement [5]. All the magnetic properties in these systems are controlled by frustrations. 

The frustration can be tuned in increasing or decreasing the interactions by substituting Mn 3+ /Mn 4+ with Fe 3+ /Fe 4+ 

(HS, S=5/2) without structural distortion. Fe doped materials in ceramics sample at similar composition have 

shown enhancement of Ps. Large single crystals of TbMn 2-xFe -xO 5 (x=0.18) have been grown by flux method 

and characterized by (ac and dc) susceptibility measurements. Single crystal neutron diffraction on E4 and TriCs 

diffractometer have been carried out respectively at the Helmoltz Zentrum Berlin and Sing, Paul Scherrer Institut. 

Below 38K, Mn/Fe spins order antiferromagnetically (τ(0.5,0,qz) qz~[0.21,0.245]). Below 15K, Tb sublattice 

is polarized by Mn/Fe one and orders antiferromagnetically below 5K. Nuclear and magnetic structure has 

investigated at 5 and 20K and be presented in this work. 

[1] E. F. Berthaut et al. , Solid. Stat. Comm. 5,25 (1925) [2]I. Akinobu and K. Kay, Ferroelectrics 169, 75 (1995) [3] N. Hur et al. 

, Nature 429, 392 (2004). [4] L. C. Chapon, Phys. Rev. Lett. 96, 976001 (2006). [5] H. Kimura, J Phys Soc Jpn 76, 074706 (2006). 

PA11 

Strain-induced ferroelectric instabilities in the epitaxial RMn2O5 (R=Dy 

and Tb) thin films 

Jong Hyun Song 1 , Jae Young Kim 2 , Sun Hee Kang 3 , Ill Won Kim 3 , Yoon Hee Jeong 4 

and Tae Yeong Koo 2 * 

1 

Physics Department, Chungnam National University, Korea 

2 

Pohang Accelerator Laboratory, Korea 

3 

Physics Department, Ulsan University, Korea 

4 

Physics Department, Pohang University of Science and Technology, Korea 

Epitaxial thin films of DyMn 2O 5 (DMO) and TbMn 2O 5 (TMO) were successfully 

grown on Nb-doped TiO 2 (110) substrates by the pulsed laser deposition to investigate 

the effects of substrate-induced strains on multiferroic properties. Synchrotron X-ray 

azimuthal angle scans and reciprocal space mappings confirmed the epitaxial qualities 

of the films. Magnetic phase transitions of the films were observed at T n = 43 K, 

showing consistent values with those of the bulk samples. Dielectric constant showed a 

steplike anomaly around 16 K, where a magneto-capacitance effect about 10 % at 8 T 

was detected. Magnetization-induced ferroelectric phases below Tn appear to become 

unstable in the epitaxial thin films due to the substrate-induced tensile strains which 

make the magnetic exchange interactions between nearby manganese ions weaker. 

PA12 

Magnetically driven ferroelectric atomic displacements in perovskitetype 

YMnO3 determined by single-crystal structure analysis 

Daisuke Okuyama 1 , Shintaro Ishiwata 2 , Youtarou Takahashi 2 , Kunihiko Yamauchi 3 , Silvia Picozzi 4 , Kunihisa 

Sugimoto 5 , Hideaki Sakai 6 , Masaki Takata 7 , Ryo Shimano 8 , Yasujiro Taguchi 1 , Taka-hisa Arima 9 and Yoshinori Tokura 2 

1 

Cross-Correlated Materials Resarch Group (CMRG), and Correlated Electron Research Group (CERG), RIKEN ASI, Japan 

2 

Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Japan 

3 

The Institute of Scientific and Industrial Research (ISIR)-Sanken, Osaka University, Japan 

4 

Consiglio Nazionale del le Ricerch-Superconducting and Innovative materials and device (CNR-SPIN), Italy 

5 

JASRI, SPring-8, Japan 

6 

School of Physics & Astronomy, University of St Andrews North Haugh, United Kingdom 

7 

RIKEN, SPring-8 Center, Japan 

8 

Department of Physics, University of Tokyo, Japan 

9 

Department of Advanced Materials Science, University of Tokyo, Japan 

Multiferroic materials have been intensively studied with a particular focus on the driving mechanism of cross-correlated 

interactions between the magnetism and electricity [1]. Many theoretical and experimental works have clarified the 

origin of the interplay between magnetism and electricity. However, the lack of information about the crystal structure in 

the multiferroic phase has prevented quantitative discussion of the ferroelectricity driven by magnetic order. In order to 

quantitatively discuss the microscopic origin of the ferroelectricity of multiferroic perovskite-YMnO 3, in which the up-updown-down-type 

(E-type) antiferromagnetic order causes a ferroelectric polarization below 30 K [2], we performed the 

crystal structural analysis for a twin-free single crystal by using synchrotron x-ray diffractometer at BL02B1 in SPring-8, and 

successfully determined the ferroelectric atomic displacements of the order of 0.001 Angstrom. The refined polar structure 

shows the characteristic bond alternation, which is consistent with that expected for the exchange striction mechanism giving 

rise to a ferroelectric polarization along the a-axis. From the experimental results of x-ray diffraction and a theoretical firstprinciples 

calculation, we quantitatively discuss the origin of the ferroelectricity in multiferroic YMnO 3[3]. 

[1] Y. Tokura and S. Seki, Adv. Mater. 22, 1554 (2010). [2] S. Ishiwata, Y. Tokunaga, Y. Taguchi, and Y. Tokura, J. Am. 

Chem. Soc. 133, 13818 (2011). [3] D. Okuyama, S. Ishiwata, Y. Takahashi, K. Yamauchi, S. Picozzi, K. Sugimoto, H. 

Sakai, M. Takata, R. Shimano, Y. Taguchi, T. Arima, and Y. Tokura, Phys. Rev. B 84, 054440 (2011). 

July 8 - 13, 2012 Busan, Korea 3 

Poster Monday


PA13 


Magnetic symmetry and electric polarization on Mn 1-xCo xWO 4 multiferroics 

Irene Urcelay - Olabarria 1 *, Eric Ressouche 1 , Jose Luis Garcia - Munoz 2 , Vassil 

Skumryev 3 , Alexander Mukhin 4 and Juan Manuel Perez - Mato 5 

1 Institut Laue Langevin, 38042 Grenoble, Cedex 9, France 

2 Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, E-08193 Bellaterra, Spain 

3 Institut Catala de Recerca i Estudis Avancats (ICREA), E-08193 Barcelona, Spain 

4 Prokhorov General Physics Institute of the Russian Acad. Sci., 119991 Moscow, Russia 

5 Dpto. De Fisica de la Materia Condensada, Fac. de Ciencia y Tecnologia, Universidad del Pais Vasco, Spain 

MnWO 4 exhibits magnetoelectric effects and belongs to the new class of frustrated multiferroics 

in which magnetic and ferroelectric order coexist [1-3]. It undergoes three successive magnetic 

phase transitions [1,2]. Below T n = 13.5 K the spins are collinear and sinusoidally modulated, 

(AF3, paraelectric). In the AF2 phase (7.5 K

PA19 

Control of coexisting ferroelectric phases in RMnO 3 crystals with fine 

tuning of 4f moment 

Tomoya Tadokoro*, Mitsuru Akaki, Haruhiko Kuroe, Tomoyuki Sekine and Hideki 

Kuwahara 

Department of Physics, Sophia University, Japan 

Recently, a new class of multiferroics with a coexistence of magnetic and ferroelectric 

ordering has been attracting revived interests. RMnO 3 (R: rare earth) with distorted 

orthorhombic structure is one of the most canonical examples for such a multiferroic material. 

In TbMnO 3 [1], the electric polarization lies along the c axis in the ferroelectric ground state, 

and the polarization does not flop without a magnetic field. Meanwhile, in Eu 0.595Y 0.405MnO 3 

without 4f moment [2], the magnetoelectric properties are quite different from those of 

TbMnO 3, although they have the same ionic radius of R-site. This result suggests that the 

magnetoelectric properties of the RMnO 3 strongly depend on the characteristics of the 

R-site 4f-moments [3]. In this study, we have systematically investigated magnetic and 

dielectric properties of Eu 0.595(Y 1-xHo x) 0.405MnO 3 (0≤x≤1) single crystals with control of 4f 

moments while keeping the average size of the R-site. In the x = 0.3 crystal, the ferroelectric 

polarization along the c axis (Pc) emerges at 25K, and then Pc is suppressed and Pa appears 

simultaneously with decreasing temperature. On further decreasing temperature, Pa 

disappears and Pc appears again. The observed reentrant behavior of the Pc phase indicates 

that Pa and Pc phases are strongly competing with each other. 

[1] T. Kimura et al., Nature 426, 55 (2003). [2] K. Noda et al., J. Appl. Phys. 99, 08S905 (2003). [3] 

M. Hitomi et al., J. Phys. Soc. Jpn. 79, 054704 (2010). 

PA20 

SmCr 3(BO 3) 4 - A new multiferroic? 

Kirill N. Boldyrev 1 *, Marina N. Popova 1 , Viktor V. Mal'tsev 2 and Nicolay I. Leonyuk 2 

1 Solid State Spectroscopy, Institute of spectroscopy RAS, Russia 

2 Faculty of Geology, Moscow State University, Russia 

Rare-earth borates with general formula RM 3(BO 3) 4 (R = Y, La-Lu; М = Al, Fe, Cr) are 

interesting for science and technology. Iron borates have rich magnetic properties stipulated by 

the presence of two interacting magnetic subsystems. It has recently been shown that RFe 3(BO 3) 4 

belong to a new class of multiferroics [1,2]. For this reason it is interesting to study rare-earth 

borates with other magnetic ion chromium. At present, little is known about these compounds. 

Antiferromagnetic phase transition has been found in NdCr 3(BO 3) 4 at T N=8.0 K [3]. This work 

describes an optical study in a wide spectral and temperature range of the SmCr 3(BO 3) 4 crystal, 

both pure and doped with erbium or neodymium. We have found that SmCr 3(BO 3) 4 undergoes 

a cascade of phase transitions at temperatures of 8.0 K, 6.7 K and 4.3 K. The first two ones are 

second-order phase transitions and, supposedly, correspond to the antiferromagnetic and (anti) 

ferroelectric ordering, respectively. First-order phase transition at 4.3 K is, most probably, the spin 

reorientation of the chromium magnetic moments. The presence of the magnetic and ferroelectric 

order allows us to talk about samarium chromium borate as a new multiferroic crystal. 

[1] A.E. Zvezdin, S.S. Krotov, A.M. Kadomtseva, G.P. Vorob’ev, Yu.F. Popov, A.P. Pyatakov, L.N. Bezmaternykh, 

E.A. Popova, JETP Lett. 81, 272 (2005). [2] A.M. Kadomtseva, Yu.F. Popov, G.P. Vorob’ev, A.P. Pyatakov, S.S. 

Krotov, K.I. Kamilov, J. Low Temp. Phys., 36(6), 640 (2010). [3] E.A. Popova, N.I. Leonyuk, M.N. Popova, E.P. 

Chukalina, K.N. Boldyrev, N. Tristan, R. Klingeler, B. Buchner, Phys. Rev. B, 76, 054446 (2007). 

PA21 

Magnetodielectric effect in the antiferromagnet SrNdFeO 4 

Jungmin Hwang 1 , Eun Sang Choi 2 , Haidong Zhou 2 , Yan Xin 2 , Jun Lu 2 and Pedro 

Schlottmann 1 

1 Florida State University/NHMFL, USA 

2 NHMFL (National High Magnetic Field Laboratory), USA 

We investigated the magnetic phase diagram of single crystals of the compound 

SrNdFeO 4 by measuring the magnetic susceptibility, the magnetization, the specific 

heat and the dielectric constant. The system has two magnetically active ions, namely 

Fe 3+ and Nd 3+ . The Fe 3+ spins are antiferromagnetically ordered below 360 K with 

the moments lying in the ab-plane, and undergo a reorientation transition at about 35- 

37 K to an antiferromagnetic order with the moments along the c-axis. A short-range, 

antiferromagnetic ordering of Nd 3+ along the c-axis was attributed to the reorientation 

of Fe 3+ followed by a long-range ordering at lower temperature.[1] At low temperatures 

and magnetic fields above 8 T the Nd 3+ moments are completely spin-polarized. The 

dielectric constant also shows anomalies associated with spin configuration changes. 

Remarkably, the sign of the dielectric changes are dependent on the direction of the 

probing electric field. A possible magnetic structure explaining all the data is presented. 

[1] S. Oyama, M. Wakeshima, Y. Hinatsu, and K. Ohoyama, J. Phys.: Condens. Matter. vol. 16, 1823 

(2004). 

PA22 

PA23 

PA24 


Mössbauer studies of Y-type hexaferrite by Aluminum doping 

Jung Tae Lim, Chin Mo Kim, Sung Wook Hyun, Mi Hee Won, Taejoon Kouh and 

Chul Sung Kim* 

Department of Physics, Kookmin University, Korea 

In recent years, the magnetoelectric effect observed in some of helicalmagnets has 

been of great interest. With Al substitution, the improvement of magnetoelectric effect 

has been reported due to reduction of the in-plane orbital moment originating from 

lowering magnetic anisotropy[1-2]. Therefore, it is important to understand the origin 

of magnetic properties in conjunction with the site distribution in hexagonal structure. 

The crystal structure of polycrystalline Ba 2Co 1.5Mg 0.5(Fe 1-xAl x) 12O 22(x = 0, 0.01, 0.02) 

samples were determined to be rhombohedral with the space group of R-3m. From the 

temperature-dependent of magnetization curves under 100 and 300 Oe, all samples 

showed ferrimagnet-to-paramagnet and helimagnet-to-ferrimagnet transitions. Base on 

the applied-field dependent magnetization measurements up to 10 kOe at 295 K, the 

saturation magnetization (Ms) and coercivity (Hc) of Ba 2Co 1.5Mg 0.5(Fe 1-xAl x) 12O 22(x = 

0, 0.01, 0.02) samples were found to be Ms = 28.0, 24.7, 23.4 emu/g and Hc = 255.4, 

222.0, 196.2 Oe, respectively. Also, from Mössbauer spectra of 295 K, Isomer shift 

values of all samples indicate that the charge states are Fe 3+ . We expect that the decrease 

in the Ms with Al ion doping is due to the fact that Al ions preferentially occupy the 

3bVI, 18hVI and 3aVI octahedral sublattices of up-spin sites[3]. 

[1] S. Ishiwata, Y. Taguchi, H. Murakawa, Y. Onose, and Y. Tokura, Science 319, 1643 (2008). [2] H. B. Lee, 

Y. S. Song, J. H. Chung, S. H. Chun, Y. S. Chai, K. H. Kim, M. Reehuis, K. Prokes, and S. Matas, Phys. Rev. 

B 83, 144425 (2011). [3] A. Collomb, M. A. Hadj Farhat and J. C. Joubert, Mat. Res. Bull. 24, 453 (1989). 

Optical spectroscopy of the triangular lattice antiferromagnets 

CuCrO 2 and alpha-CaCr 2O 4 

Michael Schmidt 1 *, Zhe Wang 1 , Franz Mayr 1 , Sandor Toth 2 , Bella Lake 2 , A. T. M. 

Nazmul Islam 2 , Vladimir Tsurkan 1 , Alois Loidl 1 and Joachim Deisenhofer 1 

1 Experimental Physics V, EKM, Institute of Physics, University of Augsburg, Germany 

2 Helmholtz Zentrum Berlin fur Materialien und Energie, Germany 

We will compare and discuss our results obtained by optical spectroscopy on CuCrO 2 

and alpha-CaCr 2O 4. While CuCrO 2 is famous for its multiferroicity [1], in alpha- 

CaCr 2O 4 a polarization can only be observed under the application of electric or 

magnetic field, despite having a closely related structure [2]. In alpha-CaCr 2O 4 we 

can see a strong, broad absorption at 57 cm -1 in the magnetically ordered state. The 

other compound shows two excitations at 11 and 48 cm -1 below the magnetic ordering 

temperature. At near infrared and visible light frequencies we observe Cr 3+ crystal field 

absorptions and below T N excitons and exciton-magnon-transitions appear. The width 

of these exciton-magnon transitions is analyzed with respect to the existence of Z2 

vortices as proposed by Kojima et al. [3]. 

[1] S. Seki et al., Phys. Rev. Lett. 101, 067240 (2008) [2] K. Singh et al., Phys. Rev. B 84, 064129 

(2011) [3] N. Kojima et al., J. Phys. Soc. Jpn. 62, 4137 (1993) 

Nuclear forward scattering in high magnetic fields; spin structures in 

the magnetic staircase of frustrated multiferroic CuFeO 2 

Cornelius Strohm 1 *, Tom T. A. Lummen 2 , Puri I. Handayani 3 , Thomas Roth 1 , Peter J. E. 

M. Van Der Linden 1 and Paul H. M. Van Loosdrecht 3 

1 European Synchrotron Radiation Facility, 6 rue Jules Horowitz 38000 Grenoble, France 

2 Department of Materials Science and Engineering, The Pennsylvania State University. 

121 Steidle Building, University Park, PA, 16802, USA 

3 Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 

AG Groningen, Netherlands 

Geometrically frustrated magnets often show a multitude of nearly degenerate ground states, which may be 

stabilized individually by the presence of small internal or external perturbations. In Copper Iron Oxide, the 

combination of geometrically frustrated interactions, with uniaxial anisotropy and spin-lattice coupling lead to 

a staircase of metamagnetic phases as a function of applied field [1-3]. We used Nuclear Forward Scattering 

of synchrotron radiation in magnetic fields up to 30 T [4, 5] to probe the spin structure of these phases up to 

the 1/3-plateau for fields parallel and perpendicular to the c axis [6]. The low field data and all transition fields 

agree with previous work. For the parallel configuration, we confirm the low field collinear spin structure. The 

data for the ferroelectric phase does not support a cycloid structure, while a 3D distribution approximating a 

multi-domain transverse proper helix structure gives qualitative agreement. For the 1/3-plateau, the anticipated 

collinear 3-sublattice structure best represents the data. In the perpendicular configuration we directly 

evidence the stability of the canted 4-sublattice phase up to the 1/3-plateau, where a collinear three sublattice 

configuration provides the best fit when a small amount of the spins oriented in the H-c plane is allowed for. 

[1] R. S. Fishman Phys. Rev. Lett. 106, 037206 (2011). [2] T. T. A. Lummen et al. Phys. Rev. B 80, 012406 (2009). [3] T. T. A. Lummen et 

al. Phys. Rev. B 81, 224420 (2010). [4] P. J. E. M. van der Linden et al. Rev. Sci. Instrum. 79, 075104, (2008). [5] C. Strohm, P. van der 

Linden and R. Rueffer Phys. Rev Lett. 104, 087601 (2010). [6] C. Strohm, T.T.A. Lummen, P.H.M. van Loosdrecht et al. unpublished. 




PA25 


Magnetic dispersion of the quasi-1D, spin-1/2, multiferroic CuO 

Stephen Michael Gaw 

Oxford University, United Kingdom 

Cupric Oxide (CuO) exhibits a magnetoelectric multiferroic phase over the narrow 

but relatively high temperature range of 213-230K [1]. The mechanism for this 

magnetoelectric coupling is not fully understood and there have been various 

theoretical models proposed [2]. The excitation spectra of CuO in the collinear 

antiferromagnetic phase (T

PB06 

Hole doping effect for the T’-Ln 2CuO 4 (Ln = La,Nd) cuprate 

Wataru Ito, Kenji Kawashima, Suguru Igarashi, Michinori Fukuma and Jun Akimitsu 

Physics and Mathematics, Aoyama Gakuin University, Japan 

The Ln 2CuO 4 (Ln=La,Nd) cuprate has two different structure types and shows the 

superconductivity for hole doping of La 2CuO 4 and electron doping of Nd 2CuO 4. From 

the Madelung energy calculation in hole doping cuprate, T c is enhanced with increasing 

the distance between Cu 2+ ions in CuO 2-layer and apical oxygens. Nd 2CuO 4 with T’type 

structure has exhibited superconductivity by electron carrier doping in CuO 2layer. 

We focused on our attention to synthesize the hole doping to T’-Ln 2CuO 4, 

in which there is no oxygen atom at apical site of CuO 2-layer. We successfully 

synthesized the polycrystalline samples of T’-(Ln 3+ ,M 2+ ) 2CuO 4 (Ln=La,Nd, M=Ca,Sr). 

In particular, T’-(La 3+ ,Sr 2+ ) 2CuO 4 was synthesized using CaH 2, which is a strong 

reducing agent at annealing temperature of 573 K [1]. The powder X-ray diffraction 

patterns showed that the samples were a single phase, and diffraction peaks indexed 

by a tetragonal symmetry of T’-type cuprate of Nd 2CuO 4. The lattice constants a and 

c show the systematic changes by increasing the M 2+ concentration. We determined 

the copper ion’s valence state using iodometry method for substituted sample of T’- 

(Ln 3+ ,M 2+ ) 2CuO 4 and confirmed that the valence of Cu ion is closed to 2+. These facts 

indicate that there is oxygen deficiency in Ln 2O 2- or CuO 2-layer of T’-(Ln 3+ ,M 2+ ) 2CuO 4 

and canceled hole carriers. 

T. Takamaysu, M. Kato, T. Noji, and Y. Koike, Physica C 471 (2011) 679-681 

PB07 

Thermodynamic properties of copper oxide Cu 6O 8YCl 1-xBr x 

Kenji Kawashima, Hiroki Takeda and Jun Akimitsu 


Copper-oxide family Cu 6O 8MCl (M=cation) has a cubic structure (Fm-3m) with Cu 6O 8-cage 

including Cl - ion in its crystal structure [1,2]. Cations of M ions are located in the cuboid space 

between Cu 6O 8-cages. The Cu 6O 8-cages share their face to form a three-dimensional network. 

Cu 6O 8YCl shows the metallic and paramagnetic behavior at low temperature. Moreover, Y and 

Cl ions have large atomic displacement parameters, suggesting the anharmonic vibrations like 

rattling phenomena of other cage structured compounds. We synthesized the polycrystalline 

samples of Cu 6O 8YCl 1-xBr x as a single phase to clarify relationship between the thermodynamic 

properties including its ground state and Cu 6O 8 cage size. In thermo-electronic measurements 

of Cu 6O 8YCl, seebeck coefficient is relatively high value (-14 μV/K at 350K), and thermal 

conductivity exhibits of low value (~0.3W/Km at 350K). The lattice constant a increases with 

increasing Br concentration, indicating expansion of Cu 6O 8-cage. The temperature dependence 

of electrical resistivity of Cu 6O 8YBr exhibits semiconducting behavior, suggesting that the 

ground state of Cu 6O 8YCl 1-xBr x changes from metallic to semiconducting by increasing Br 

concentration. Thermal conductivity undergoes very little change. However, S is enhanced by 

substituting Br. These facts indicate that the ground state and physical properties are sensitive on 

the Cu 6O 8-cage size in Cu 6O 8YCl 1-xBr x system. 

[1] G.Zouganel, K.Bushida, I.Yazawa N.Terada, M.Jo, H.Hayakawa, and H.Ihara, Sol. St. Comm. 80 

(1991) 709. [2] K.Bushida, I.Yazawa, G.Zouganel, T.Connard, N.Terada, K.Kaneko, M.Hirabayashi, 

and H.Ihara, Physica C 185-189 (1991) 2727. 

PB08 

Nodal superconducting gap in Bi 2201 investigated by low temperature 

specific heat measurements 

Naoki Momono 1 *, Nobutaka Saikai 1 , Tohru Kurosawa 2 , Yusuke Amakai 1 , Sigeyuki 

Murayama 1 , Hideaki Takano 1 , Migaku Oda 2 and Masayuki Ido 2 

1 Applied Sciences, Muroran Institute of Technology, Japan 

2 Department of Physics, Hokkaido University, Japan 

In order to examine the gap magnitude near nodes in Bi 2201 cuprate superconductors, 

we have measured the magnetic field dependence of low temperature electronic 

specific heat Cel(T, H), which is much more bulk-sensitive than standard ARPES and 

STS. In optimally doped Bi 2201, the coefficient of T-linear term in Cel at T


PB12 


Enhancement of Ti-Se bonding length in CuxTiSe 2 

Sang Wook Han 1 , Han-jin Noh 2 , Daehyun Kim 3 , Jihoon Hwang 3 , Jeong Soo Kang 3 , W. 

F. Pong 4 and Soon Cheol Hong 1 * 

1 Department of Physics and EHSRC, University of Ulsan, Korea 

2 Department of Physics, Chonnam Nation University, Korea 

3 Department of Physics, The Catholic University of Korea, Korea 

4 Department of Physics, Tamkang University, Taiwan 

Titanium diselenide (TiSe 2) undergoes a charge-density-wave (CDW) instability characterized by 

a 2x2x2 real-space superstructure [1]. TiSe 2 is not superconducting at low temperature, but CDW 

is suppressed and superconductivity stabilized either by Cu intercalation (maximum Tc =4.5 K) 

[1] or pressure (maximum Tc = 1.8 K) [2]. The resulting phase diagram looks similar to that of 

cuprates with the difference that the spin-density wave order has been replaced by a CDW one. The 

mechanism at the origin of the CDW and superconducting phases in TiSe 2 is currently unknown. 

The charge-order instability in pure TiSe 2 is known to involve both exciton formation and a strong 

electron-phonon coupling, it may be expected that the superconducting phase will likewise involve 

a combination of both excitonic [3] and phonoic [4] contributions. In order to elucidate the role of 

Cu atoms, we have investigated the Cu-doped TiSe 2 by employing both x-ray absorption near-edge 

structure (XANES) and extended x-ray absorption fine-structure (EXAFS). The Cu atoms enhance 

the bonding length of Ti and Se atoms with lowering temperature. Concurrently, the Debye-Waller 

factors change at the transition temperatures of CDW and superconductivity, respectively. 

[1] E. Morsan et al., Nature Phys. 2, 544 (2006). [2] A. F. Kusmartseva et al., Phys. Rev. Lett. 103, 236401 (2009). [3] C. 

Monney et al., Phys. Rev. Lett. 106, 106404 (2011). [4] M. Calandra and F. Mauri, Phys. Rev. Lett. 106, 196406 (2011). 

PB13 

Para-conductivity of (Bi 0.25Cu 0.25Li 0.25Tl 0.25)Ba 2Ca 2Cu 3O 10-δ 

superconductors 

Qurat-ul Ain and Nawazish Ali Khan 

Physics, Quaid-i-azam university islamabad pakistan, Pakistan 

Excess conductivity analyses of as-prepared and oxygen post-annealed (Bi 0.25Cu 0.25Li 0.25Tl 0.25) Ba 2Ca 2 Cu 3 

O 10-δ samples were carried out by following Lorentz-Danish (LD) model beyond the transition region and 

Ginzburg-Landau (GL) equations in the critical regime. In these studies the effect of oxygen annealing on the 

thermodynamic fluctuations of the Cooper pairs just above the Tc is performed by using Aslamazov-Larkin (AL) 

theory. We have observed a major increase in the width of 3D AL and 2D LD regimes after post-annealing in 

oxygen atmosphere. Moreover, with the oxygen post-annealing the coherence length along the c-axis has also 

been found to increase along with inter-plane coupling. The thermodynamic critical magnetic field, the lower 

critical magnetic field, the upper critical magnetic field, the critical current density and penetration depth are also 

calculated from the analysis of four regions namely critical (cr), three dimensional (3D), two dimensional (2D) 

and zero dimensional (0D) region that appeared as the temperature increases. The values of Fermi velocity, phase 

relaxation time, penetration depth, κ values and energy required to break apart the cooper pairs are increased with 

the annealing of oxygen. This shows that in (Bi 0.25Cu 0.25Li 0.25Tl 0.25)Ba 2Ca 2Cu 3O 10-δ sample, the optimum density 

of carriers in the conducting CuO2 is essential for enhanced superconductivity in these compounds. 

1) Qiang Lia, M. Suenaga, Junho Gohng, D.K.Finnemore, T. Hikata and K. Sato Phys.Rev. B 46, 3195-3198 

(1992). 2) V. V. Schmidt, The physics of superconductors (Springer, New York, 1997), p. 45. 3)A.L. Solovjov, 

V.M. Dmitriev, and H.-U. Habermeier, Phys. Rev. B 55, 8551 (1997). 4)A.L. Solovjov, H.-U. Habermeier, and T. 

Haage, Fiz Nizk. Temp. 28, 144 (2002) [Low Temp. Phys. 28, 99 (2002)] 5] C. J. Lobb, Phys. Rev. B 36 (1987) 

3930. 6] A. I. Abu Aly, I. H. Ibrahim, R. A. Awad and A. El-Harizy, J. of Supercond. Nov. Magn. 23 (2010) 1325. 

PB14 

Charge transfer instability governs unconventional behavior of doped 

cuprates 

Alexander Moskvin and Alexey Korolev 

Department of Theoretical Physics, Ural Federal University, Russia 

A large body of experimental data points towards an unique charge transfer (CT) 

instability of parent insulating cuprates. True CT gap in these compounds is believed 

to be as small as 0.4-0.5 eV as derived from the midinfrared absorption measurements 

[1] rather than 1.5-2.0 eV as usually derived from the fundamental absorption 

measurements. Actually we deal with a competition of the conventional (3d9) ground 

state and a CT state with formation of electron-hole dimers which evolves under doping 

to an unconventional bosonic system [1-3]. Making use of a quantum Monte-Carlo 

(QMC) technique we study the evolution of the phase state of CuO 2 planes in a model 

CT unstable cuprate La 2-xSr xCuO 4. Nonisovalent doping gives rise to a suppression of 

parent antiferromagnetic phase with the nucleation of the inhomogeneous supersolid 

CO+BS phase characterized by a charge (CO) and off-diagonal Bose superfluid 

(BS) order parameters which competition results in a generic T-x phase diagram 

with a distinct pseudogap regime due to a charge ordering and emergence of a local 

superconductivity. Our QMC simulation does reproduce all the main features of the 

T-x phase diagrams for doped cuprates. 

1. A.S. Moskvin, Phys. Rev. B 84, 075116 (2011). 2. A.S. Moskvin, Low Temp. Phys. 33, 234 (2007). 3. 

A.S. Moskvin, Phys. Rev. B 69, 214505 (2004). 


PB15 

The effect of CdO nanoparticles doping and sintering time on the 

structure and critical temperature of Bi 2223 superconductor 

Morteza Zargar Shoushtari*, S Ebrahim Musavi Ghahfarokhi and Nahid Hossinzadeh 

Physics, Shahid Chamran University of Ahvaz, Iran 

The effect of CdO nanoparticles doping and sintering time on the structure and critical 

temperature of Bi 2223 superconductor M. Zargar shoushtari1, S. E. Musavi Ghahfarokhi, 

N. Hossinzadeh 1 Department of physics, Shahid Chamran University of Ahvaz, 

Ahvaz, I. R. Iran Presenting author: zargar@scu.ac.ir In this paper, Bi 1.64Pb 0.36Sr 2Ca 2xCd 

xCu 3O y (x= 0.0, 0.01, 0.02, 0.03, 0.04, 0.1) superconductor is prepared by using the 

solid state method. The effect of doping CdO nanoparticles for different sintering times 

(t= 90, 180 and 270 h) on the stracture and critical temperature has been studied. The 

structural analysis was carried out using XRD and SEM measurements. The critical 

temperature was measured by the standard four-probe method. The results showed that 

the more sintering time increases the critical temperature such that the samples prepare 

at 270h have maximum critical temperature. Also, our results reveal that, the Bi 1.64Pb 

0.36Sr 2Ca 1.97Cd 0.03Cu 3O y sample has the highest Tc (Tc= 137.5k) in between the doped 

samples. 

PB16 

Charging/Discharging and overcurrent characteristics of GdBCO coils 

using various partial insulation winding methods 

Yoon Hyuck Choi, Kwang Lok Kim, Oh Jun Kwon, Hyun-jin Shin and Haigun Lee* 

Department of Materials Science and Engineering, Korea University, Korea 

Eliminating the insulation in high temperature superconducting (HTS) windings can 

allow a system to be compact and well protected by bypassing the excessive current 

flow that occurs through the turn-to-turn contact between uninsulated turns. However, 

the time constant of coils without insulation is much higher than that of completely 

insulated coils due to the absence of insulation resistance, resulting in a coil chargedischarge 

rate that becomes quite slow. Therefore, this study examined the charging, 

operating, and discharging behaviors of Gd-Ba-Cu-O (GdBCO) HTS coils with Kapton 

insulation every 3, 6, or 9 turns to investigate the effect of changes in insulated turns 

on the coil’s time constant. Furthermore, to verify the demagnetization phenomena of 

the coils in the excessive current condition, the overcurrent characteristics of partially 

insulated GdBCO coils were evaluated and discussed in detail. 

This work was supported by the <strong>International</strong> Collaborative R&D Program of 

the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the 

Korean government Ministry of Knowledge Economy (20118520020020). 

PB17 

Effect of filter shape on the capture efficiency of a high gradient 

magnetic separation (HGMS) system 

Young-gyun Kim, Jung-bin Song, Dong Gyu Yang, Jongseok Lee and Haigun Lee* 


High gradient magnetic separation (HGMS) using a ferromagnetic filter enables the 

capture of fine particles of even weakly magnetic materials by the high gradient of 

the magnetic field. In general, such a field gradient, which can determine the capture 

capability of the HGMS system, is mainly affected by the filter’s mesh size, wire 

diameters, and materials. Therefore, this study examined the capture efficiency of the 

HGMS system with respect to mesh size and wire diameter to investigate the effect of 

filter shape on gradient magnitude. Furthermore, the capture efficiency of various filter 

shapes was also examined and compared with the simulation. 

This study was supported by the Ministry of Knowledge Economy (MKE), 

Korea, under the IT R&D Infrastructure Program supervised by the National IT Industry Promotion 

Agency (NIPA-2011-(B1110-1101-0002)).

PB18 

Effects of various epoxy impregnations on the electrical properties of 

GdBCO-coated conductor racetrack pancake coils 

Hyun-jin Shin, Kwang Lok Kim, Yoon Hyuck Choi, Oh Jun Kwon, Yeonjoo Park and 

Haigun Lee* 


A high temperature superconducting (HTS) field coil in a wind turbine generator is 

generally impregnated with epoxy resin to provide high mechanical integrity against 

the rotational vibrations. However, if cooled down, the epoxy-impregnated coil wound 

with second generation (2G) HTS tape usually encounters superconducting property 

degradation and delamination due to the thermal contraction mismatch between the 

epoxy and the HTS tape. Therefore, to investigate the effect of various epoxies on 

the coil’s electrical properties, the GdBCO racetrack pancake coils impregnated with 

Stycast 2850-FT, Epikote 828R, or Epon 815 were characterized using Ic testing. 

Furthermore, degradation of the coils’ superconducting properties was also examined 

using repetitive cooling tests. 




PB19 

Crystal structure of (Ru 0.5Cu 0.5)(Sr 1.47Ba 0.2Nd 0.33)(NdCe)Cu 2O 10-δ 

compound 

H.k. Lee 1 and Y.i. Kim 2 

1 Physics, Kangwon National University, Deptartment of Physics, Korea 

2 Korea Research Institute of Standards and Science, Korea 

PB20 

Absence of broken time reversal symmetry below the surface of 

(110)-oriented YBCO superconductors 

Hassan Saadaoui 1 *, Zaher Salman 1 , Thomas Prokscha 1 , Hannu Huhtinen 2 and Elvezio 

Morenzoni 1 

1 

Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, 5232 Villigen PSI, 

Switzerland 

2 

Department of Physics, Wihuri Physical Laboratory, University of Turku, FI-20014 

Turku, Finland 

WITHDRAWN 

Low-energy muon spin rotation (LE-μSR) is a very sensitive local magnetic probe to 

study magnetism on a nanometer length scale near the surface of materials and thin 

films. Here, we report the results of a search for spontaneous magnetization due to a 

time reversal symmetry breaking phase in the superconducting state of (110)-oriented 

YBCO films, expected to develop near the surface in this orientation. Zero field and 

weak transverse field measurements performed using LE-μSR few nm inside optimallydoped 

YBCO-(110) films showed no appearance of spontaneous magnetization below 

the superconducting temperature up to 2.9 K, contrary to tunneling measurements. Our 

results give an upper limit of 0.01 mT for spontaneous internal fields in these films. 

PB21 

PB22 

PB23 


Transport properties of the twin boundary of YBa 2Cu 3O 7 thin films on 

LaAlO 3 substrates 

Sung Hoon Lee 1 , Sung-hak Hong 1 , Jae-hyuk Choi 2 and Soon-gul Lee 1 * 

1 Department of Display and Semiconductor Physics, Korea University, Korea 

2 Division of Convergence Technology, Korea Research Institute of Standards and 

Science, Korea 

We have fabricated superconducting YBa 2Cu 3O 7 (YBCO) twin-boundary junctions and 

studied their critical transport properties. The twin boundary junctions were fabricated 

by using a focusd-ion-beam (FIB) etching technique and of the size of nominally 150 

nm in width, 100 - 120 nm in length, and 100 nm in thickness. The junctions showed 

Tc = 91 K with 1 K transition width and a high critical current density of Jc = 15 MA/ 

cm2 at 77 K. Measured current-voltage (I-V) curves showed the resistively-shuntedjunction 

(RSJ) characteristics near the transition with excess current associated 

with flux-flow effect. High-resolution X-ray diffraction (HR-XRD) spectra strongly 

indicated the possibility that the epitaxially-grown YBCO film was also twinned in 

commensurate with the twinning of the LAO substrate. Misorientation of the c-axis of 

YBCO at the twin boundary is believed to be the major cause of the weak link behavior 

of the bridge across the twin boundary. 

Displacement waves of oxygen atoms in the Bi, Pb -2223 lattice 

of superconducting composites annealed in an oxygen reduced 

atmosphere 

Tatiana Krinitsina*, Svetlana Sudareva, Elena Kuznetsova and Julia Blinova 

Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Russia 

The Bi, Pb -2223 /Ag composites annealing in oxygen-nitrogen atmosphere is believed to 

reduce the number of the accompanying phases, to make contacts between crystallites 

closer and to increase the critical current. The goals of this study were determining 

the 2223 lattice changes at annealing in the reduced oxygen atmosphere, revealing 

the reasons of these changes and their effect on the ceramics superconductivity. After 

such annealing the transversely-polarized waves of oxygen atoms displacement in 

[010] direction are observed in the 2223 phase by electron diffraction analysis. These 

waves may appear due to the lack of oxygen in the 2223 lattice or to the nitrogen 

penetration in it. As demonstrated by the X-ray photo-electron spectroscopy and 

nuclear microanalysis, nitrogen does not interact with the 2223 lattice, and the oxygen 

index decreases to 9.67, which is lower than the stoichiometric. Thus, the atomic 

displacement waves result from the lack of oxygen in Bi-O bilayers. 

Irreversibility line in the CNT and carbon doped YBCO 


Sedigheh Dadras 1 *, Nallayian Manivannan 2 , Vahid Daadmehr 1 and Kee Hoon Kim 3 

1 physics, Other Academic, Iran 

2 physics, Other Academic, India 

3 Other Academic, Korea 

Irreversibility Line in the CNT and Carbon Doped YBCO Superconductors 

S. Dadras 1 *,N. Manivannan 2 , V. Daadmehr 1 , and K. H. Kim 2 1 Magnetic and 

Superconducting Res. Lab., Department of Physics, Alzahra University, 

P.C.1993891176, Tehran, Iran. 2eXtreme Multifunctional Physics Laboratory, 

FPRD, School of Physics and Astronomy, Seoul National University, Seoul 151-747, 

Republic of Korea. *dadras@alzahra.ac.ir s_dadras2001@yahoo.com Abstract. We 

investigated the irreversibility line (IL) of the carbon nano tube (CNT) and carbon 

doped YBa 2Cu 3O 7-δ superconductor samples using magneto-resistive measurement 

results. Irreversibility line moves to higher magnetic fields for CNT doped and to lower 

magnetic field for carbon doped YBCO samples respect to the undoped sample. 




PB24 


Nonlocal excitations and 1/8 singularity in cuprates 

Yoshiro Kakehashi*, M. Atiqur R. Patoary and Sumal Chandra 

Department of Physics, University of the Ryukyus, Japan 

Low energy excitations and unusual behaviors of electrons in the 2D cuprates have 

been the question under debates. Especially the non Fermi liquid behaviors and the 

pseudogap remain unresolved theoretically because of the limited range of the intersite 

correlations and the limitation of the momentum and energy resolutions in the 

theory. We present here our results for the momentum-dependent single-particle 

excitation spectra of the 2D Hubbard model, which are based on the full self-consistent 

projection operator method. The theory self-consistently takes into account the longrange 

intersite correlations with use of the off-diagonal effective medium, and allows 

us to calculate the excitation spectra with high energy and momentum resolutions. We 

obtained the excitation spectra being consistent with the QMC results and found at T=0 

that the nonlocal excitations enhance the Mott-Hubbard gap and create the shadowband 

excitations due to strong antiferromagnetic correlations. The present theory yields 

the characteristic hole concentration 1-n* = 0.123 (=1/8) at which the van Hove type 

singular peak appears just on the Fermi level at T=0, while it is 1-n* = 0.15 at finite 

temperatures in the 4x4 DCA. The present result suggests the emergence of the 1/8 

stripe phase due to the Fermi surface instability. 

PB25 

Magnetic memory in a ceramic YBCO superconductor composed of 

sub-micron size grains 

Hiroyuki Deguchi 1 *, Takuya Ashida 1 , Mitsuhiro Syudou 1 , Masaki Mito 1 , Makoto 

Hagiwara 2 , Kuniyuki Koyama 3 and Seishi Takagi 1 

1 Faculty of Engineering, Kyushu Institute of Technology, Japan 

2 Faculty of Engineering and Design, Kyoto Institute of Technology, Japan 

3 Faculyu of Integrated Arts and Science, The Univercity of Tokushima, Japan 

The nonequilibrium nature of a ceramic YBCO composed of sub-micron size grains is investigated 

by measurements of the dc magnetizations.The ceramic YBCO is considered as random Josephsoncoupled 

networks of 0 and π junctions and shows successive phase transition. The first transition 

occurs inside each grain at Tc1= 81 K and the second transition occurs among the grains at Tc2=47 K. 

The magnetic glass behavior similar to those of spin-glasses is observed below Tc2.[1] Theoretically, 

the frustration effect due to the random distribution of π junctions should lead to the chiral-glass state, 

as predicted by Kawamura and Li.[2] The memory phenomena are investigated by recording the 

zero-field-cooled and thermoremanent magnetization temperature dependence measured on heating 

after the cooling process with and without field switches.[3] There are memory effects of the halt 

at Ts=44 K imprinted in the system on the re-heating the sample. In the case without field switches 

at Ts, the influence of the halt is confined to a narrow temperature region near the halt temperature, 

whereas the memory effects of the halt employing a field switch is extended over a wide temperature 

region below Ts. The results suggest that chiral-glass ordering occurs at Tc2 in the ceramic YBCO. 

[1] H.Deguchi et al. , J. Phys. <strong>Conference</strong> Series 320 (2011) 012076. [2] H.Kawamura and Li , J. 

Phys. Soc. Jpn. 66 (1997) 2110. [3] E.L.Papadopoulou and P.Nordblad , Eur. Phys. J. B 22 (2001) 187. 

PB26 

Phase diagram of high-tc superconductivity and antiferromagnetism 

revealed by Cu-NMR in multilayered cuprates 

Hidekazu Mukuda 1 *, Sunao Shimizu 1 , Akira Iyo 2 and Yoshio Kitaoka 1 

1 Osaka University, Japan 

2 National institute of Advanced Industrial Science and Technology (AIST), Japan 

We present site-selective nuclear magnetic resonance (NMR) studies on multilayered 

cuprates, which have uncovered the intrinsic phase diagram of antiferromagnetism 

(AFM) and high-temperature superconductivity (HTSC) for a disorder-free CuO 2 

plane with hole carriers. We revealed the existence of the AFM metallic state in doped 

Mott insulators, the uniformly mixed phase of AFM and HTSC, and the emergence of 

d-wave SC with a maximum Tc just outside a critical carrier density, at which the AFM 

moment on a CuO 2 plane disappears. These results can be accounted for by the Mott 

physics based on the t-J model, where the superexchange interaction J among spins 

within the plane plays a vital role as a glue for Cooper pairs or mobile spin-singlet 

pairs. 


PB27 

Magnetism and superconductivity in CeCu2Ge2 under high pressures 

and magnetic fields 

Fuminori Honda 1 *, Takashi Maeta 2 , Yusuke Hirose 2 , Atsushi Miyake 3 , Tetsuya Takeuchi 4 , 

Katsuya Shimizu 3 , Tomoko Kagayama 3 , Rikio Settai 2 and Yoshichika Onuki 2 

1 

Graduate School of Engineering Science, Osaka University, Japan 

2 

Graduate School of Science, Osaka University, Japan 

3 

KYOKUGEN, Osaka University, Japan 

4 

Low Temperature Center, Osaka University, Japan 

CeCu 2Ge 2 with the ThCr 2Si 2 type tetragonal structure is an antiferromagnet with TN = 4.2 K 

(AF1) and shows two kinds of superconducting phases named a low-Tsc phase (SC1) and 

a high-Tsc phase (SC2) under high pressures [1]. We have grown CeCu 2Ge 2 single crystals 

by Sn-flux method and studied an electronic state under high pressures and magnetic fields 

by means of the electrical resistivity measurement. We have found two anomalies at TN = 

4.1 K and TN’= 1.3 K at 2.6 GPa for example, implying a Neel temperature and a change of 

magnetic structures with the first order. In the temperature-pressure phase diagram, two kinds 

of magnetic phases named AF1 and AF2 appear and merge at 5 GPa. At pressures higher than 

5 GPa, the AF2 phase becomes dominant. The AF2 phase can be another antiferromagnetic 

phase, since the metamagnetic transition to the AF1 phase is observed around 3 T for the H || [001] 

direction. At 8.2 GPa, pressure-induced superconductivity (SC1) is induced below Tsc(onset) = 

0.5 K. The upper critical field is 30 kOe for H || [001]. The AF2 phase coexists with SC1 below 

10 GPa and the AF2 phase disappears above 11 GPa, revealing only SC1 phase. 

[1] E. Vargoz and D. Jaccard: J. Magn. Magn. Mater. 177-181 (1998) 294. 

PB28 

Doping and temperature dependence of Fermi arc in cuprate 


Shiping Feng*, Huaisong Zhao and Lulin Kuang 

Department of Physics, Beijing Normal University, China 

The pseudogap observed in the excitation spectrum as a suppression of spectral weight 

in the normal-state of cuprate superconductors is thought to be key to understanding 

the mechanism of superconductivity. Within the framework of the kinetic energy driven 

superconducting mechanism [1], we [2] study the evolution of the Fermi arc with 

doping and temperature by considering the interplay between the superconducting gap 

and normal-state pseudogap [3]. It is shown that the system in the underdoped regime 

is a nodal liquid, and the length of the Fermi arc increases with increasing temperatures, 

in qualitative agreement with the experimental observation on cuprate superconductors 

[4]. Our results also show that the unusual behavior of the quasiparticle dispersion and 

Fermi arc in cuprate superconductors is intriguingly related to the effect of the normalstate 

pseudogap. 

[1] Shiping Feng, Phys. Rev. B 68, 184501 (2003); Shiping Feng et al., Physica C 436, 14 (2006). [2] 

Huaisong Zhao, Lulin Kuang, and Shiping Feng, unpublished. [3] Shiping Feng, Huaisong Zhao, 

and Zheyu Huang, arXiv:1109.3973. [4] A. Kanigel et al., Nature Phys. 2, 447 (2006); U. Chatterjee 

et al., Nature Phys. 6, 99 (2010). 

PB29 

Static spin correlation in Pr2-xCaxCuO4 Studied by neutron scattering 

Kenji Tsutsumi 1 *, Tomohiro Miura 1 , Masanori Enoki 2 , Kentaro Sato 3 , Masato 

Matuura 4 , Kazuyoshi Yamada 5 and Masaki Fujita 6 

1 

Department of Physics, Tohoku University, Japan 

2 

Kysyu Institute Technology, Japan 

3 

Department of Physics, Tohoku university, Japan 

4 

IMR, Tohoku University, Japan 

5 

WPI, Tohoku University, Japan 

6 

IMR, Tohoku Univesity, Japan 

It is well known that a small amount of hole-doping into La2CuO4 having K 2NiF 4type 

(attributed as T) crystal structure destroys the antiferromagnetic (AF) order and 

superconducting phase appears with further hole doping. On the other hand, recent 

experimental study on Nd 2CuO 4-type (attributed as T’) structured La 2CuO 4 with no 

apical oxygen clarified contrasting properties to that in T-structured La 2CuO 4; that 

is Neel temperature is different in two structured systems. [1] Therefore, the crystal 

structure is an important factor to determine the physical properties. In order to gain 

further insight into the physics of doped Mott insulator, we performed neutronscattering 

measurement on T’-Pr 2-xCa xCuO 4. The as-grown and annealed x=0.10 

samples shows the long-range AF order below TN~290 K. This result suggests a weak 

Ca doping effect on the AF order, which is contrast to the results in T-La 2-xSr xCuO 4. In 

my poster, the details of doping dependence of magnetic order will be presented. 

[1] R. Hord et al., Phys. Rev. B 82, 180508 (2010).

PB30 

High-energy neutron scattering study of spin excitation in slightlyoverdoed 

La1.82Sr0.18CuO4 Kentaro Sato 1 *, Masato Matsuura 2 , Masaki Fujita 2 , Kenji Tsutsumi 1 , Masanori Enoki 3 

and Kazuyoshi Yamada 4 

1 

Physics, Tohoku University, Japan 

2 


3 

Kyushu Institute of Technology Graduate School of Life Science and Systems Engineering, Japan 

4 WPI, Tohoku University, Japan 

Antiferromagnetism in the doped cuprate Mott-insulator has been investigated due to its rich physics and close 

connection with the high-Tc superconductivity. A finding of a generic form of spin excitations showing the 

“hourglass” shape in the different class of superconductors La 2-x(Sr,Ba) xCuO 4 (La -214 ) [1] and YBa 2Cu 3O 6+d [2] 

suggests a common role of spin fluctuations in the mechanism of high-Tc superconductivity. Recently, Vignolle 

and co-workers revealed the existence of two energy scales in the spin excitations of optimally-doped La -214 

[3] and pointed out the possibility of different origins for the excitation separated by energy. To study the dual 

nature of spin excitations in more detail, we have performed a high-energy neutron scattering measurement on 

slightly-overdoped La 1.82Sr 0.18CuO 4. The constant-energy spectrum at low temperature is a broad single-peak in 

a wide energy range below ~150meV, although the peak-slitting was observed below ~10meV. This feature is 

somehow similar to the dispersion of spin excitation in the overdoped La -214 . On the other hand, the integrated 

intensity shows sharp and broad maximums at ~18meV and ~45meV, respectively, as is the case of optimallydoped 

system. In the poster, we will present the temperature dependence of the overall excitation spectrum and 

discuss the dual nature of the hourglass-shaped excitation. 

[1] J. M. Tranquada et al., Nature 429, 534 (2004). [2] S. M. Hayden et al., Nature 429, 531 (2004). 

[3] B. Vignolle et al., Nature Physics, 3, 163 (2007). 

PB31 

Quantized massive gauge fields around the doped holes in high-tc 

cuprates and the relation to iron pnictides 

Ikuzo Kanazawa* 

Physics, Tokyo Gakugei University, Japan 

Recently Yazdani[1] has suggested strongly that the high-energy(up to about 400meV) 

hole-like excitations of the normal state are a direct predictor of the strength of 

pairing, although he cannot present a model for the excitations. The present author has 

proposed the mechanisms of evolution of the Fermi arc with increasing temperature[2] 

and with increasing of hole-doping[3] in high-Tc cuprates. In this study, we present 

one model for the high-energy excitations, which play an important role on strength of 

Cooper pairing, and show that quantized massive gauge fields induce short-range spinfluctuations 

and short-range orbital fluctuations[4,5]. 

[1] A.Yazdani, J.Phys.Condense Matters 21,164214(2009) [2]I.Kanazawa, J.Phys.Chem.Solids 

66,1388(2005) [3]I.Kanazawa, Physica C 470,5183(2010) [4]H.Kontani and S.Onari,Phys.Rev. 

Lett.104,157001(2010) [5]Y.Yanagi et al. J.Phys.Soc.Jpn. 79,123707(2010) 

PB32 

Ho-doping effect on the static stripe order in La214 superconductor 

Masaki Fujita 1 *, Masanori Enoki 2 , Satoshi Iikubo 2 , Kenji Tsutsumi 3 , Kentaro Sato 3 , 

Masato Matsuura 1 and Kazuyoshi Yamada 4 

1 

Institute for Materials Research, Tohoku University, Japan 

2 

Graduate School of Life Science and Systems Engineering, Kyushu Institute of 

Technology, Japan 

3 


4 

World Premier <strong>International</strong> Research Center, Tohoku University, Japan 

We have performed elastic neutron scattering experiments on the superconducting 

La 1.84Ho 0.04Sr 0.12CuO 4 to study the substation effect of cation with the large magnetic 

moment at La site on the static spin correlation. In the Ho-free sample with the hole 

concentration of 0.12, spatially modulated magnetic order is known to be stabilized 

below T_spin ~ 30K [1]. In the present Ho-doped sample, we found the appearance of 

magnetic peaks at (0.5, 0.5±0.118, 0) positions below T_spin ~ 35K, which is similar 

to the observation in the pristine sample. Furthermore, the volume corrected intensity 

in the Ho-free and Ho-doped samples is comparable, suggesting a negligible effect of 

Ho-substitution at La site. These results are quite contrast to the huge enhancement 

of magnetic intensity and the increase of T_spin by substituting magnetic Fe 3+ ions 

onto CuO 2 planes [2]. Therefore, the stability of stripe order induced by the cation 

substitution is sensitive to the substituted site. 

[1] H. Kimura et al., Phys. Rev. B 59, 6517 (1999). [2] M. Fujita et al., J. Phys. and Chem. Solids. 

69, 3167 (2008). 

PB33 

PB34 

PB35 


High field paramagnetic meissner effect in Ca doped YBa2Cu3O7-δ single crystals 

Valdemar Vieira 1 *, Augusto Falck 1 , Fabio Dias 1 , Douglas Da Silva 1 , Paulo Pureur 2 , 

Jacob Schaf 2 and Frederik Fabris 3 

1 

Instituto de Fisica e Matematica, UFPEL, Brazil 

2 

Instituto de Fisica, UFRGS, Brazil 

3 

Dresden High Magnetic Field Laboratory, HZ Dresden-Rossendorf, Germany 

We report on dc magnetization of a series of Y 1-xCa xBa 2Cu 3O 7-δ (x = 0, 0.0025, 0.05, 0.1) single 

crystals with the goal to study the role of the hole doping on the paramagnetic Meissner effect 

(PME). [1] The magnetization as a function of the temperature, under constant magnetic field, 

was recorded adopting the field-cooled procedure, Mfc(T) as well as magnetic relaxation, Mfc(t) 

for a measurement time up to 50.000s. The Mfc(T) data of our single crystals shows the usual 

superconductor diamagnetic response when magnetic fields up to 0.5 kOe are applied. In contrast, 

when H > 0.5 kOe are applied, the Mfc(T) data displays a systematic reduction of the superconductor 

diamagnetic response until it became predominantly paramagnetic at higher fields not showing 

tendency to a temperature saturation behavior in the doped samples. This behavior is a signature of 

the high field paramagnetic Meissner effect (HFPME) in HTSC. [2,3] The Mfc(t) data reveals that 

the paramagnetic moment of the samples increase continuously as a function of the time. In specific, 

the Ca doping promotes an enhancement of the HFPME intensity as compared with no doped 

sample. We suggest the flux compression scenario to explain the HPME in your samples. [4] 

[1] V. N. Vieira et al. Phys. Rev. B 76 (2007) 024518-1. [2]F. T. Dias, et al. Physica C 470, S111 (2010). 

[3] F.T. Dias et al. Phys. Rev. B 70 (2004) 224519. [4] A.K. Geim et al. Nature 396 (1998) 144. 

Growth of a-axis oriented thin films of infinite-layer Sr 1-xLa xCuO 2 

Hiroyuki Akatsuka*, Keita Sakuma, Kenji Ueda and Hidehumi Asano 

Crystalline Materials Science, Nagoya University, Japan 

Electron-doped infinite-layer compound Sr 1-xLa xCuO 2 has the simplest crystal structure, 

and is suitable for fundamental studies of high-Tc superconductivity as well as device 

applications. The epitaxially grown c-axis oriented Sr 1-xLa xCuO 2 thin films with Tc of around 

40 K were fabricated on the lattice matched substrates like DyScO 3 and KTaO 3[1]. Since 

the in-plane coherence length ξab(4.5nm) of Sr 1-xLa xCuO 2 is larger than the out-of-plane 

coherence length ξc(0.3nm)[2], the a-axis oriented film is favorable for junction fabrication. 

In this paper, we will make the first report on the preparation and properties of a-axis 

oriented thin films. Sr 0.9La 0.1CuO 2(a0=0.3949nm, c0=0.341nm) thin films were prepared 

by magnetron sputtering. KTaO3(a0=0.3989nm), SrTiO 3(a0=0.3905nm), (La0.18Sr0.82) 

(Al0.59Ta0.41)O 3(LSAT)(a0=0.3868nm) and LaAlO 3(a0=0.3791nm) substrates were used 

to investigate the effect of the lattice mismatch. On KTaO 3, LSAT and SrTiO 3 substrates, 

c-axis oriented films were obtained. In contrast, on LaAlO 3 substrates with a large lattice 

mismatch (-4.2%), a-axis oriented films were obtained. One possible reason for the a-axis 

growth is due to a higher-order lattice matching, that is, lattice mismatch between ten unit 

cell of Sr 0.9La 0.1CuO 2(001)(3.10nm) and nine unit cell of LaAlO 3(100)(3.412nm) is 0.03%. 

As-grown thin films showed a semiconducting behavior. Post deposition annealing resulted 

in the a-axis oriented films with Tconset of around 30 K. 

[1] S. Karimoto and M. Naito, Appl. Phys. Lett. 84, (2004) 12. [2] V. P. Jovanovic, Z. Z. Li, and H. 

Raffy, Phys. Rev. B 80, (2009) 024501. 

Thermal stability of an epoxy-impregnated HTS racetrack coil without 

turn-to-turn insulation for rotating machines 

Oh Jun Kwon, Kwang Lok Kim, Yoon Hyuck Choi, Hyun-jin Shin and Haigun Lee* 


Since use of the no-insulation (NI) technique creates a compact system with better 

thermal and electrical stability, use of a high temperature superconducting (HTS) 

coil without turn-to-turn insulation is now being proposed for the field coil in HTS 

rotating machines. Epoxy impregnation of field coils is generally needed to protect 

the coil against mechanical disturbances by time-varying magnetic fields and to 

provide high mechanical integrity against the rotational vibrations. Therefore, to use 

the NI technique on the practical HTS field coil of a rotating machine, it is essential 

to obtain sufficient information on the thermal and electrical behaviors of the epoxyimpregnated 

NI coil. In this study, the quench characteristics of epoxy-impregnated 

HTS racetrack coils without turn-to-turn insulation were investigated using overcurrent 

tests. Furthermore, the thermal stability of the epoxy-impregnated NI coil at various 

current charging rates was also investigated and discussed. 

This work was supported by a grant from the <strong>International</strong> Collaborative 

R&D Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) 

funded by the Korean government Ministry of Knowledge Economy (20118520020020). 




PB36 


Design, fabrication, and testing of a cooling system using solid nitrogen 

for a 3 T/60-mm RT bore superconducting HGMS 

Jung-bin Song, Kwang Lok Kim, Dong Gyu Yang, Yoon Hyuck Choi, Jongseok Lee 

and Haigun Lee* 


To develop a compact and stable superconducting high gradient magnetic separator 

(HGMS) for the removal of copper and silica from chemical mechanical polishing 

wastewater, a 3 T/60-mm room temperature bore HGMS using solid a nitrogen cooling 

system was fabricated. The HGMS’s magnet was assembled using 18 GdBCOcoated 

conductor double pancake coils, each of which was wound without turn-toturn 

insulation. The cooling capabilities of the solid nitrogen cooling system for the 

superconducting HGMS were examined using cool-down, warm-up, and chargingdischarging 

tests in the temperature range of 10-20 K. The capture efficiency of the 

superconducting HGMS using the solid nitrogen cooling system was also evaluated 

using a filtration test. 




PB37 

Purification of chemical mechanical polishing wastewater using a 2G 

HTS high gradient magnetic separation system 

Dong Gyu Yang, Jung-bin Song, Young-gyun Kim, Jongseok Lee, Yeonjoo Park and 

Haigun Lee* 


Magnetic separation efficiency is related to the strength of the applied magnetic field 

and the field gradient used to trap the magnetic particles. The use of a magnet wound 

with high temperature superconducting (HTS) tape enables the magnetic separation 

system to more efficiently remove wastewater contaminants than their conventional 

counterparts due to the facile generation of a higher magnetic field due to the absence 

of Joule heating losses. In this study, we fabricated and tested the second generation 

(2G) HTS high gradient magnetic separation (HGMS) system for the purification of 

chemical mechanical polishing wastewater. The capturing efficiencies of the 2G HTS 

HGMS system were investigated in terms of the wastewater flow velocity and turbidity 

using repetitive separation tests. Furthermore, the appropriate purification process for 

enhancing removal efficiency was also discussed. 



Agency (NIPA-2011-(B1110-1101-0002)). 

PB38 

Effect of liquid cryogen on a 2G HTS magnet using a mixed cryogen 

cooling system 

Kwang Lok Kim, Jung-bin Song, Yoon Hyuck Choi, Dong Gyu Yang and Haigun 

Lee* 


A cooling system employing a mixture of solid cryogen with small amounts of liquid 

cryogen was reported for use in high temperature superconducting (HTS) applications. 

Although the liquid cryogen in the mixed cryogen cooling system can improve the 

thermal contact between the solid cryogen and the HTS magnet, it is essential that 

further studies be performed because there are insufficient data about the thermal/ 

electrical behaviors of the HTS magnet that has been subjected to mixed cryogen. 

Therefore, in this study, the quench/recovery characteristics of mixed cryogen-cooled 

2G HTS magnets with respect to liquid cryogen amount were examined to investigate 

the influence of the solid/liquid ratio on the thermal/electrical stabilities of the HTS 

magnet. 





PB39 

Removal of silica and copper ions from CMP wastewater via magnetic 

seeding aggregation using superconducting HGMS 

Jongseok Lee, Jung-bin Song, Dong Gyu Yang, Yeonjoo Park and Haigun Lee* 


With the increased demand for semiconductor devices, the purification of chemical 

mechanical polishing (CMP) wastewater in the semiconductor industry has become 

of great importance for worldwide environmental protection. Superconducting high 

gradient magnetic separation (HGMS) is one promising technique due to its compact 

design and efficient and accurate removal of particles. For the HGMS, various 

ferromagnetic materials were required to coagulate non-magnetic heavy metal ions 

and various nanoparticles in CMP wastewater. In this study, we suggested the use of a 

coagulation process optimized by magnetic seeding aggregation at various pH values 

for the separate yet simultaneous removal of copper ions and silica nanoparticles. The 

filtration efficiency of the flocculated substances in an HGMS was evaluated using 

turbidity measurements. 



Agency (NIPA-2011-(B1110-1101-0002)). 

PB40 

Joint characteristics of ReBCO-coated conductors using various fusion 

splicing techniques 

Yeonjoo Park 1 , Hyun-jin Shin 1 , Young-gyun Kim 1 , Young Kun Oh 2 and Haigun Lee 1 * 

1 Department of Materials Science and Engineering, Korea University, Korea 

2 K-joins Co., Korea 

For superconductor splicing, it is essential that joint resistance be minimized between 

superconducting tapes to operate with the persistent current mode and lengthen them. We have 

already proposed the concept of RE-Ba 2Cu 3O 7-δ (ReBCO) tape fusion splicing technology 

that is based on the unique ReBCO thermal and structural properties. The melting point of 

ReBCO decreases as the surrounding oxygen partial pressure decreases, allowing for low 

temperature splicing and recovery of the superconductivity lost during the joining process by a 

subsequent oxygenation annealing process. In this study, the fusion splices with changing joining 

parameters, such as PO 2, heating rate, peak temperature and holding time, cooling rate, oxygen 

flow rate, temperature and holding time for oxygenation annealing, tape clamping pressure, 

and so on were performed using the following two splicing methods: 1) the ReBCO-ReBCO 

interface was directly connected by fusion, and 2) the Ag layer was diffused in a face-to-face 

manner without solder. The joint characteristics were evaluated in terms of joint resistances, 

critical currents, and index numbers. Furthermore, the sample morphologies and structures were 

analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. 




PC01 

Bulk electronic structure of LaRu 2P 2 probed by soft X-ray angleresolved 

photoemission spectroscopy (SX-ARPES) 

E. Razzoli 1 , M. Kobayashi 1 , V. N. Strocov 1 , B. Delley 1 , Z. Bukowski 2 , J. Karpinski 3 , N. 

C. Plumb 1 , M. Radovic 1 , J. Chang 1 , T. Schmitt 1 , L. Patthey 1 , J. Mesot 1 and M. Shi 1 * 

1 Paul Scherrer Institute, Switzerland 

2 Laboratory for Solid State Physics, ETH Zurich, Switzerland 

3 Laboratory for Solid State Physics, ETH Zuurich,, Switzerland 

WITHDRAWN

PC02 

Superlattice quantum critical point in the cubic metal (Sr/Ca) 3Ir 4Sn 13 

Lina Esther Klintberg 1 , Swee Kuan Goh 1 *, Patricia Alireza 1 , Paul Saines 1 , David 

Tompsett 1 , Peter Logg 1 , Jinhu Yang 2 , Bin Chen 2 , Kazuyoshi Yoshimura 2 and Malte 

Grosche 1 

1 University of Cambridge, United Kingdom 

2 University of Kyoto, Japan 

Structural self-organisation is a central theme in condensed matter physics. Often, the 

symmetry of a given parent structure is lowered by subtle structural variations which 

decrease the electronic degeneracy and thereby the total energy. Examples include 

Jahn-Teller and Peierls distortions and, more generally, modulated lattice distortions, 

or superlattices. The quasi-skutterudite compounds R3T4X13, where R is an earth 

alkaline or rare-earth element, T is a transition metal and X is a group-IV element, 

form either in a simple cubic structure, called the I-phase, or in the variant I'-phase, 

which can be viewed as a superlattice distortion of the I-phase. Here, we investigate 

the borderline system (Sr/Ca) 3Ir 4Sn 13, which we report forms in the I-phase, but 

transforms into the I'-phase on cooling. Hydrostatic pressure is used to suppress the 

second order structural transition enabling the first comprehensive investigation of a 

structural quantum critical point in a three-dimensional charge density wave driven 

superconductor. 

PC03 

Unconventional superconductivity in PuCoIn 5: An NQR investigation. 

Hiroshi Yasuoka 1 , Georgios Koutroulakis 1 *, Hiroyuki Chudo 2 , Eric D. Bauer 1 and Joe 

D. Thompson 1 

1 Los Alamos National Laboratory, USA 

2 Advanced Science Research Center, Japan Atomic Energy Agency, Japan 

PC04 

Pressure effect on the structural and superconducting transitions in a 

caged compound PrRh2Zn20 Y Sugano 1 , T Ohsuka 1 , K Umeo 2 *, N Nagasawa 1 , T Onimaru 1 and T Takabatake 1 

1 

AdSM, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8530, 

Japan 

2 

N-BARD, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, 

Japan 

WITHDRAWN 

PrRh 2Zn 20 crystallizes in a cubic CeCr 2Al 20-type structure, where the Pr 3+ ion is 

encapsulated in a polyhedron formed by 16 zinc atoms. The crystalline electric field 

ground state of 4f2 electrons in the Pr ion was found to be a nonmagnetic Γ3 doublet 

[1]. The resistivity of this compound shows a superconducting transition at TSC = 0.060 

K and a hysteretic behavior in the temperature range from 140 K to 470 K, which 

originates from a structural phase transition. In order to reveal the interplay between the 

structural and superconducting transitions, we have measured the electrical resistivity 

ρ for a single crystalline sample under pressures up to 2 GPa and at temperatures down 

to 0.052 K. With increasing pressure up to 2 GPa, the anomaly in ρ(T) at TS = 160 

K shifts to higher temperatures by the ratio of 3 K/GPa. This indicates that the lowtemperature 

phase (T


PC08 


A novel superconductivity in Ir oxides with large spin-orbit coupling 

Hiroshi Watanabe*, Tomonori Shirakawa and Seiji Yunoki 

RIKEN, Japan 

Recently, the 5d transition metal oxides such as Sr 2IrO 4 and Ba 2IrO 4 have attracted 

much attention as a novel Mott insulator. In these materials, three t2g orbitals of 

Ir atoms are hybridized with each other by the spin-orbit coupling of 5d electrons. 

As a result of the quantum entanglement of spin and orbital degrees of freedom, 

an anomalous Jeff=|L-S|=1/2 state is realized, which causes interesting properties 

[1]. To clarify the properties of this system, we have studied the ground state of 

the three-orbital Hubbard model with a spin-orbit coupling term using variational 

Monte Carlo method and variational cluster approximation [2]. Here, we study the 

electronic states when carriers are doped in this three-orbital system and discuss the 

possibility of superconductivity. The obtained ground state phase diagram reveals 

the antiferromagnetic state, stable around the electron density n=5, is destabilized 

by carrier doping and the ground state turns to be superconducting under a certain 

condition. Similar to the high-Tc cuprates, a large asymmetry between electron doping 

(n>5) and hole doping (n

PC14 

Lateral Josephson junction induced by inverse proximity effect 

Lu-kuei Lin 1 , Ssu-yen Huang 1 , Jin-hua Huang 2 and Shang-fan Lee 1 * 

1 Institute of Physics, Academia Sinica, Taiwan 

2 Materials Science and Engineering, National Tsing Hua University, Taiwan 

A Josephson junction is characterized by a phase coherent transfer of the Cooper pairs 

across a weak link between two superconducting electrodes. The proximity effect at 

the interface between a superconductor and a ferromagnetic metal occurs, implying 

that the Cooper pairs penetrate into the ferromagnet. It results in spatial oscillations 

of the superconducting order parameter in the ferromagnet. Recently an opposite 

effect so-called “inverse proximity effect”, i.e. the induction of a magnetic moment in 

a superconductor in contact with a ferromagnet attracted much attention. We utilize 

the inverse proximity effect in superconductor-ferromagnet bilayer to generate lateral 

Josephson junctions. The weak link is created by a strong ferromagnet Py strip across 

a superconductor Nb bridge due to inverse proximity effect and forms a region S’. 

Samples with different size of weak link region S’ were fabricated by varying the Py 

strip width from 0.5 to 2 μm. The junctions exhibit a modulation of the critical current 

in perpendicular magnetic field similar to a Fraunhofer interference pattern even when 

the S’ has such long distance as 2 μm, which proves the dc Josephson effect and spin 

triple component taking place. 

PC15 

13C NMR study of charge fluctuation induced superconductivity in 

beta''-(BEDT-TTF)4[(H 3O)Ga(C 2O 4) 3]-C 6H 5NO 2 

Yoshihiko Ihara*, Harumi Seki and Atsushi Kawamoto 

Department of Physics, Graduate School of Science, Hokkaido univerisity, Japan 

Superconductivity emerging near antiferromagnetism has been thoroughly investigated. 

The antiferromagnetic fluctuations in the vicinity of quantum critical point are believed 

to induce such superconductivity. In this paper, we report experimental evidence that 

points to the novel possibility of superconducting state, that is, charge fluctuation 

induced superconductivity. The molecular superconductor beta''-(BEDT-TTF)4[(H 3O) 

Ga(C 2O 4) 3]-C 6H 5NO 2 demonstrates a charge instability at 100 K, before showing the 

superconducting transition at 7.5 K [1]. Besides, this salt is intriguing because of its 

high upper critical field of 33 T, which is almost three times the Pauli limiting field 

[2]. We performed the 13C NMR experiment and revealed on the basis of the Knight 

shift measurement that the spin-singlet superconductivity is realized in the charge 

disproportionate state. The nuclear spin-lattice relaxation rate measurement detects 

the strong electron-electron correlations slightly above superconducting transition 

temperature. Since 13C NMR technique can probe only the magnetic properties, we 

measured in-plane resistivity as a complementary probe and found an abrupt increase 

below 10 K. These results lead us to address the importance of charge fluctuations to 

induce superconductivity. 

[1] A. I. Coldea et al., PRB 69, 085112 (2004). [2] A. F. Bangura et al., PRB 72, 014543 (2005). 

PC16 

Ac susceptibility components of a thin type-II superconducting 

annulus carrying a radial current 

Aliakbar Babaei Brojeny*, Mostafa Molavi, Asghar Sharbaf Zadeh and Mahdi 

Sohrabi 

Department of Physics, Isfahan University of Technology, 84156-83111, Iran 

By assuming a spatial dependence on the sheet-current density, we have investigated 

the real (χ') and imaginary parts (χ'') of the susceptibility of a thin type-II 

superconducting annulus in the absence and also in the presence of a transport radial 

current, using the Bean critical state model in which the critical current density is 

assumed to be independent of the local magnetic field. The results of our calculations 

on the components of the magnetic susceptibilities in two cases and for the different 

aspect ratios are compared with each other. The comparison shows that by applying a 

radial current to the sample, the imaginary part of the susceptibility is increased. We 

have also studied the variations of the χ'' with respect to χ' for a several aspect ratios. 

1-Ali A. Babaei-Brojeny and John R. Clem, Phys. Rev. B 68, 174514 (2003). 2-Ali A. Babaei- 

Brojeny, Asghar Sharbaf Zadeh and Mostafa Molavi, Journal of Physics:<strong>Conference</strong> Series…(2012). 

PC17 

PC18 

PC19 


Pressure evolution of superconductivity in β-pyrochlore oxides 

Takeshi Matsubara 1 , Takayuki Isono 2 , Daisuke Iguchi 1 , Yo Machida 1 , Koichi Izawa 1 *, 

Bernard Salce 3 , Jacques Flouquet 3 , Hiroki Ogusu 2 , Jun-ichi Yamaura 2 and Zenji Hiroi 2 

1 

Department of physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, 

Japan 

2 

ISSP, University of Tokyo,Kashiwa, Chiba 277-8581, Japan 

3 

SPSMS, CEA-Grenoble, 38054 Grenoble Cedex 9, France 

The β-pyrochlore oxides AOs 2O 6 (A = K, Rb and Cs) have attracted much interest because 

of their unusual electronic properties including the superconductivity[1]. A unique feature 

of this system is the presence of the remarkable anharmonic vibration of an A ion, called 

'rattling' motion. Although it has been pointed out by various studies that the rattling motion 

plays an important role for the occurrence of superconductivity in this system, its concrete 

role for superconductivity have not been understood yet. In order to clarify the interplay 

between the rattling motion and superconductivity, we study the pressure (P) evolution of 

superconductivity in magnetic field (H) at low temperatures (T). The rattling motion could be 

affected by pressure through the modification of the crystal lattice. In this paper, we report the 

T-H-P phase diagram of AOs 2O 6 and K 0.8Rb 0.2Os 2O 6 obtained by specific heat measurements 

and discuss the pressure variation of the electron-phonon coupling and phonon frequency. 

We demonstrate that the non-monotonous pressure dependence of the transition temperature 

can be explained in terms of the competition between the enhancement of the electronphonon 

coupling and the suppression of the phonon frequency. 

[1]Y.Nagao et al., J.Phys.Soc.Jpn. 78 064702 (2009) 

Inverse magnetic proximity effects in superconducting Sn-Ni 

nanoparticle assemblies 

Chi-hung Lee, Yen-cheng Chen, Chin-wei Wang and Wen-hsien Li* 

Physics, National Central University, Taiwan 

Although the superconductivity of the element Sn, in their bulk form, is believed 

to be associated with the spin-singlet s-wave pairing, it is now known that the 

superconducting parameters are strongly dependent on the physical size of the system. 

Here, we report on the results of magnetization, magnetic susceptibility and resistivity 

measurements made on Sn, Sn-Ni and Sn-Au nanoparticle assemblies. The thermal 

profiles of the magnetic susceptibility of Sn nanoparticle assemblies can be described 

by Scalapino’s expression. Inverse magnetic proximity effect is observed, as the TC of 

the superconducting nanoparticles is found to be noticeably increased, when magnetic 

Ni nanoparticles are introduced into the vicinity of the superconducting nanoparticles. 

Closing up the spatial separations between Sn and Ni nanoparticles leads to a further 

increase in TC. There is a critical Ni composition and a critical spatial separation 

between the magnetic and superconducting nanoparticles that must be reached before 

their magnetic proximity will suppress the superconductivity. On the other hand, the 

inverse proximity effect of the In-Ni nanoparticle assemblies is not observed in the (Sn- 

C)14(Au-A)86 nanoparticle assembly, where TC of Sn remains essentially unaltered 

by cold pressing. A qualitative mechanism is proposed to understand the present 

observations. 

Pressure study on anisotropic electrical resistivity of Hg-doped 

CeRhIn 5 

Soonbeom Seo 1 , Sol Ju 1 , E.d. Bauer 2 , J.d. Thompson 2 and Tuson Park 1 * 

1 Physics, Sungkyunkwan University, Korea 

2 Physics, Los Alamos National Laboratory, USA 

The stoichiometric compound CeRhIn 5 is a prototypical antiferromagnet where Ce 4f 

moments align below 3.8 K. With increasing pressure, the antiferromagnetic ordering 

of CeRhIn 5 disappears and the superconducting state emerges. When doped with 

Hg, the antiferromagnetic transition TN initially decreases and develops a different 

magnetic structure with further increasing Hg concentration. In this research, we 

focused on a 0.45 % Hg-doped CeRhIn 5, where TN is suppressed from 3.8 K to 3.4 K 

and the magnetic structure is same as that of the undoped compound with Q=(1/2, 1/2, 

0.298). By applying hydrostatic pressure, we suppressed TN to zero and measured the 

anisotropic electrical transport measurements for the electrical current applied within 

and perpendicular to the Ce-In plane. Evolution of the anisotropic transport property 

across the quantum critical point will be discussed. 




PC20 


Control of superconductivity in parity mixing superconductors 

Li 2T 3B(T:Pt,Pd) by non-magnetic impurity and defect doping 

Guizhi Bao 1 , Gaku Eguchi 2 , Akiko Ono 3 , Yoshihiko Inada 4 , Yoshiteru Maeno 2 and Guo-qing Zheng 1 

1 Department of Physics, Okayama University, Japan 

2 Department of Physics, Graduate School of Science, Kyoto University, Japan 

3 Graduate School of Education, Okayama university, Japan 

4 Graduate school of Natural Science and Technology, Graduate School of Education, 

Okayama university, Japan 

Recently, superconductors with noncentrosymmetric crystal structures like Li 2T 3B (T:Pd, Pt) have been the focus 

of in-depth research with its parity mixing nature. Previous studies of NMR and penetration depth measurements 

suggested that Li 2Pt 3B is a spin triplet dominant and Li 2Pd 3B is a s-wave spin singlet dominant superconductor, 

approximately 2:3 and 4:1 ratio of spin singlet and spin triplet order parameters, respectively [1-3]. It is known 

that s-wave superconductor without the sign inversion of the order parameter on the Fermi surface is not affected 

by non-magnetic impurity and defects doping as contrasted to that of a non s-wave superconductor. In this 

research, we prepared different quality samples by substituting B with Al. Sample qualities were estimated by 

residual resistivity. Li 2Pd 3B exhibits the small Tc suppression attributed by the non-magnetic impurities and 

defects, while Hc 2(0) value increased. This behavior is similar in ordinary s-wave superconductor. While results 

for Li 2Pt 3B show that Tc and Hc 2(0) value were found to be suppressed by disorder. However, the rate of Tcsuppression 

by disorder has been found to be not so large to be explained by the pair-breaking effect expected for 

the non s-wave superconductor. Further details will be outlined during the actual presentation. 

[1] Nshiyama M, Inada Y, and Zheng Guo-qing, 2007 Phys.Rev. Lett. 98, 047002 [2] Nshiyama M, Inada Y, 

and Zheng Guo-qing, 2005 Phys.Rev. B 71, 220505 [3] H. Q. Yuan et al., Phys. Rev. Lett. 97 (2006) 017006 

PC21 

Pressure-induced metal-insulator transition of Mott insulator Ba 2IrO 4 

Daisuke Orii 1 *, Masafumi Sakata 1 , Atsushi Miyake 1 , Katsuya Shimizu 1 , Hirotaka 

Okabe 2 , Masaaki Isobe 2 , Eiji Muromachi 2 and Jun Akimitsu 3 

1 KYOKUGEN, Osaka Univ., Japan 

2 NIMS, Japan 

3 Aoyama Gakuin Univ., Japan 

Ba 2IrO 4 is an antiferromagnetic Mott insulator, because the large spin-orbit 

interactions of the 5d electrons in Ir atoms lift the energy levels. The magnetic 

moment is suppressed to ~ 0.34 μB/Ir atom because of the spin fluctuation, and the 

Neel temperature TN is ~ 240 K. These magnetic properties are similar to ones of 

La 2CuO 4, which is the parent material of a high-Tc superconductor [1-3]. The crystal 

structures are also similar. Here, in order to inhibit the insulating state and to search the 

superconducting phase, the electrical resistivity of Ba 2IrO 4 has been performed under 

high pressure. According to the present results, metal-insulator transition was observed 

at 28 GPa, but not the superconducting transition above 50 mK. 

[1] H. Okabe et al.: Phys. Rev. B, 83, 155118 (2011). [2] D. Vaknin et al.: Phys. Rev. Lett., 58, 2802 

(1987). [3] T. Freltoft et al.: Phys. Rev. B, 36, 826 (1987). 

PC22 

Charge and spin order of charge stripe ordered La2-xSrxCoO4 Paul G. Freeman 1 , E. Wechke 2 , E. Schierle 2 , A. T. Boothroyd 3 and D. P 3 

1 

Helmholtz-Zentrum Berlin, Germany; EPFL, Lausanne, Swizerland; ILL, Grenoble, 

France 

2 

Helmholtz-Zentrum Berlin, Germany 

3 

Department of Physics, Oxford University, United Kingdom 

Since the discovery of charge stripe order in the cuprates, the role of stripes in high 

temperature superconductivity, and whether charge stripes are ubiquitous to the cuprates 

has been under intensive debate[1]. Recent neutron scattering studies of cobalt and 

manganese based charge-stripe ordered materials have demonstrated how the striking 

hourglass excitation spectrum of the cuprates is consistent with charge-stripe order[2,3]. 

One important experimental observation in charge-stripe ordered La 2-xSr xCoO 4 is 

however presently missing, direct observation of stripe charge order itself. Although 

alternative forms of charge order has been observed in cobaltates in the form of a 

checkerboard charge ordered state and a proposed charge river state[4,5]. Here we use 

the technique of resonant soft x-ray scattering to study by diffraction the spin and charge 

ordering of the charge-stripe phase of La 2-xSr xCoO 4. We report our analysis of the diffuse 

order recorded in our study, this study completes the evidence for the charge-stripe 

model of this system that is used to explain the hourglass spin excitation spectrum. 

[1] M. Tranquada, et. al., Nature 375, 561 (1995). [2] A. T. Boothroyd, et. al., Nature 471, 341-344 

(2011). [3] H. Ulbrich, et. al., arXiv:1112.1799. [4] I. A. Zaliznyak, et. al. Phys. Rev. Let. 85, 4353 

(2000). [5] N. Sakiyama, et. al. Phys. Rev. B 78, 180406(R) (2008). 


PC23 

Strong enhancement of superconductivity in inorganic electride 

12CaO•7Al 2O 3:e- under high pressure 

Shigeki Tanaka 1 *, Tomoki Kato 1 , Atsushi Miyake 1 , Tomoko Kagayama 1 , Katsuya 

Shimizu 1 , Sung Wng Kim 2 , Satoru Matsuishi 3 and Hideo Hosono 4 

1 KYOKUGEN, Osaka University, Japan 

2 Frontier Research Center, Tokyo Institute of Technology, Japan 

3 Materials and Structures Laboratory, Tokyo Institute of Technology, Japan 

4 Frontier Research Center, Materials and Structures Laboratory, Tokyo Institute of 


The nanoporous main group oxide 12CaO•7Al 2O 3 (C 12A 7) is a compound in the 

system CaO-Al 2O 3 and is used widely as a constituent of aluminous cements. It can be 

transformed from a wide-gap insulator to a metal with substituting electrons for anions 

in cages constituting a positive frame. A superconducting transition was found at Tc 

= 0.2-0.4 K for C 12A 7 electride (C 12A 7:e-) doped with anionic electrons to 2*10^21 

per cubic centimeter[1]. We carried out the ac-susceptibility measurement of single 

crystalline C 12A 7:e- under high pressure using a piston-cylinder cell and a diamond 

anvil cell. With increasing pressure, Tc monotonically increases up to 1.0 K at 2.4 GPa. 

In addition, the upper critical field Hc 2 (T) and -dHc 2/dT becomes larger. The density of 

states at the Fermi level is estimated to increase under high pressure, in agreement with 

dTc/dP > 0. 

[1] M. Miyakawa et al., J. Am. Chem. Soc. Vol. 129 (2007) 7270. 

PC24 

Superconductivity in conical magnets 

Gertrud Zwicknagl 

Technische Universitaet Braunschweig, Germany 

The influence of spatially modulated exchange fields on superconducting properties 

is discussed. Of particular interest are conical magnets where the non-collinear 

magnetic structure permits to control the symmetry of the pair wave function. The 

limiting cases - homogeneous ferromagnetic and anti-ferromagnetic exchange 

field - have been extensively studied. The central focus of the present work is the 

variation with modulation length of the superconducting properties. I discuss the 

evolution of the induced triplet components and analyze their orbital structures. Spinresolved 

tunnelling spectra highlight the cross-over from typical pair-breaking to pairweakening 

which occurs when the magnetic modulation length is comparable to the 

superconducting coherence length in the absence of exchange fields. 

PC25 

Observation of Bose-metallic phase in Ta Films 

Sungyu Park* and Eunseong Kim 

Center for Supersolid & Quantum matter Research, Department of Physics, KAIST, 

Daejeon, 305-701, Korea 

Superconductor-insulator transition has been induced by tuning film thickness or 

magnetic field [1-3]. Recent electrical transport measurements of Ta thin films 

revealed an interesting intermediate metallic phase which intervened superconducting 

and insulating phases in the zero temperature limit [4]. The resistance of Ta films in 

this regime exhibited a sharp drop at the transition temperature but a finite saturated 

value at low temperatures. In addition, IV characteristic curves showed non-linear 

response, indicating possible appearance of a new metallic phase. The intriguing 

quantum metallic phase can be interpreted as a consequence of vortex dynamics or 

dislocation response in the vortex lattice [5]. Here we present systematic studies on the 

superconductor-metal-insulator transition and nonlinear transport in two dimensional 

Ta films. 

[1] M. P. A. Fisher, PRL 65, 923 (1990) [2] D. B. Haviland, et al. PRL 62. 2180 (1989) [3] V. F. 

Gantmakher, et al. JETP Letters 71, 160 (2000) [4] Y. Li, et al. PRB 81, 020505 (2010) [5] D. 

Ephron, et al. PRL 76, 1529 (1996)

PC26 

Non-trivial vortex dynamics in a superconducting Corbino disk 

Masaru Kato and David E. Fujibayashi 

Department of Mathematical Sciences, Osaka Prefecture University, Japan 

Using the molecular dynamics method for vortex motion and the finite element method 

for heat transport, we investigate the vortex motion in a superconducting corbino disk, 

where an external current is injected at the center of the disk and flows toward the 

perimeter of the disk. For this geometry, vortices move circularly, but velocity of the 

vortices is large around the center and small at the edge of the disk, according to the 

magnitude of the external current density. Moving vortices cause resistivity and heat, 

and therefore there appear non-uniform temperature distribution. This non-uniform 

temperature distribution makes the vortices out of their circular motion through entropy 

force. Therefore the motion in the superconducting corbino disk becomes non-trivial 

one. We focused on the how heat transport to the outside of superconductors, such as 

a substrate under the superconductor, affect the vortex motion. And we find that firstly 

the vortices move toward the edge of the disk, but finally they form laminar flow for 

large heat resistance to the substrate but they show a peculiar ordered state for small 

heat resistance. We show details of these vortex motions. 

PC27 

Coexistence of ferromagnetism and superconductivity in single-phase 

Bi 3Ni nanostructures 

Thomas Herrmannsdoerfer 1 *, Richard Skrotzki 1 , Rico Schoenemann 1 , Yurii Skourski 1 , 

Joachim Wosnitza 1 , Daniel Koehler 2 , Regine Boldt 2 and Michael Ruck 2 

1 Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, Germany 

2 Department of Chemistry and Food Chemistry, TU Dresden, Germany 

We have demonstrated the coexistence of superconductivity and ferromagnetism in Bi 3Ni 

nanostructures which have been prepared by making use of novel chemical-reaction paths [1]. We 

have characterized their magnetic and superconducting properties by means of SQUID magnetometry, 

ac susceptometry, and electrical-transport measurements in a wide field and temperature range. Here, 

we also present recent experiments on novel nanostructures, such as monodisperse spherical clusters 

with a diameter of 8 nm as well as nanofibers. Pulsed-field susceptibility data up to 60 T allow for 

a determination of the saturation magnetization of Bi 3Ni nanostructures. Resistivity measurements 

performed on moderately compacted Bi 3Ni nano fibers down to 40 mK have shown clear evidence 

for the existence of an isosbestic point. Superconductivity in confined Bi 3Ni emerges in the 

ferromagnetically ordered phase and is stable up to remarkably high magnetic fields. This coexistence 

would most likely be possible in the case of triplet pairing. The absence of an inversion center of the 

lattice of Bi 3Ni nanostructures would allow for the formation of an antisymmetric spatial component 

of the electron-wave function and could lead to a significant admixture of a spin-triplet component of 

the order parameter. Part of this work was supported by EuroMagNET, EU-contract No. 228043. 

[1] T. Herrmannsdorfer, R. Skrotzki, J. Wosnitza, D. Kohler, R. Boldt, M. Ruck, Phys. Rev. B 83, 140501(R) (2011) 

PC28 

Observation of twofold symmetry breaking in the gap function of 

heavy-fermion superconductor UPt3 Yo Machida 1 , Atsushi Itoh 1 , Yoshitaka So 1 , Koichi Izawa 1 *, Yoshinori Haga 2 , Etsuji 

Yamamoto 2 , Noriaki Kimura 3 and Yoshichika Onuki 4 

1 

Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan 

2 

Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan 

3 

Graduate School of Science and Center for Low Temperature Science, Tohoku Universit, Miyagi 

980-8577, Japan 

4 

Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan 

WITHDRAWN 

PC29 

PC30 

PC31 


Investigation of the three-dimensional electronic structure of MgB 2 by 

soft X-ray angle-resolved photoelectron spectroscopy 

Y. Sassa 1 *, M. Mansson 1 , B. M. Wojek 2 , M. Kobayashi 3 , V. Strocov 3 , O. Tjernberg 2 , N. 

D. Zhigadlo 1 and B. Batlogg 1 

1 Laboratory of Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland 

2 Materials Physics, Royal Institute of Technology KTH, S-16440 Kista,, Sweden 

3 Swiss Light Source, Paul Scherrer Institute, CH- 5234 Villigen PSI, Switzerland 

WITHDRAWN 

Vortex channeled effect in Nb thin film with artificial pinning array 

Tian-chiuan Wu 1 *, Lance Horng 2 , Jong-ching Wu 2 and Rong Cao 2 

1 Department of Electrical Engineering, Nation Formosa University, Taiwan 

2 Department of Physics, National Changhua University of Education, Taiwan 

The vortex pinning effect is a fundamental characteristic in type II superconductors. 

Vortex dynamics in the mixed state in type-II superconductors is strongly influenced by 

the pinning centers. We have studied a channeled-like pinning potential in Nb thin films 

which is formed by the pinned vortices. Nb films with periodic pinning arrays show 

matching effects in the magnetic field dependence of the resistivity and Hall Effect. It 

is suggested that the motion of interstitial vortices has great influence by the channel. 

When vortices propagate through these arrays, both the longitudinal and transversal 

voltages show cusp-like anomalies at matching fields. Vortices can be guided by the 

channel formed between pinned vortices. 

[1] R. Cao, T.C. Wu, P.C. Kang, J.C. Wu, T.J. Yang, Horng Lance, Solid State Comm. 143 (2007) 

171. [2] M. Baert, V.V. Metlushko, R. Jonckheer, V.V. Moshchalkov, Y. Bruynseraede, Phys. Rev. Lett. 

74 (1995) 3269. [3] J.E. Villegas, E.M. Gonzalez, M.I. Montero, Ivan K. Schuller, J.L. Vicent, Phys. 

Rev. B 68 (2003) 224504. 

Role of the third dimension on the spectral property and transport 

behaviour in layered cuprates 

Bhagya Sindhu Tewari 

Physics, University of Petroleum and Energy Studies, Dehradun, India 

In the present work, we have analyzed the influence of the third dimension coupling 

on the normal state electronic spectra of bilayer cuprates employing Green’s function 

equations of motion approach within tight binding extended Hubbard model and 

model, which necessarily includes the three site exchange interaction (J3) and the inter 

unit cell resonant tunneling (T12). The influence of inter unit cell resonant tunneling on 

the out of plane (c-axis) conductivity has also been analyzed for cuprates employing 

Kubo formula and Green’s function technique. On the basis of numerical computation, 

it is found that the inter cell resonant tunneling (T12) introduces a broadening in the 

spectral function and increases the c-axis conductivity. It is also found that the J3 term 

suppresses the bilayer splitting in the electronic spectra. These results are viewed in 

terms of recent ARPES measurements. 

[1] S. Chakravarty, et. al, Science 61 (1993) 337 [2] E.Dagotto, Rev. Mod. Phys. 68(1994)763 

[3] Y.D.Chaung, et.al, Phys. Rev. Lett. ,87 (2001) 117002, [4] B.S. Tewari et. al, Eur.Phys.J. B, 

66(2008)67 [5] Q.P.Li, et. al, Phys. Rev. B, 48(1993) 437 [6] R.kubo, J.Phys soc. Japan, 28, (1957) 

1402 [7] W.C. Wu, et. Al, J. Supercond. 11, 305 (1998) 305 [8] B.S. Tewari et. al, Physica C 468 

(2008) 237 [9] B.E.C. Koltenbah, et. Al, Rev. Mod. Phys. 60 (1997) 23 




PD01 


Ground dielectric state of the Mott-doped material 

Vladimir Gavrichkov* 

Krasnoyarsk, Kirensky Institute of Physics, Russia 

Using analytic calculations, within the framework of the Russell-Saunders scheme 

we investigated the dependence of the number of valence states on a doping level x 

in the full package of the valence bands for the Mott-doped material. According to 

our calculations the total number of valence states Nv(x) coincides with the number 

of electrons per unit cell (N-x) if there is a ban (both spin S-, and orbit L-) on the first 

removal quasiparticle states (frs). Thus is formed an insulating ground state of the 

doped material at the T=0K. We believe that such materials with the forbidden frs 

states can be attributed the manganites with the L-forbidden states and cobaltites with 

the S-forbidden states. 

PD02 

Temperature-dependent phonon anomalies in uranium and plutonium 

compounds 

Peter S Riseborough* 

Physics, Temple University, USA 

There is evidence that a number of heavy-fermion/mixed-valent materials show 

strongly renormalized hybridization gaps either at the Fermi-energy or close to the 

Fermi-energy. In the former case, a heavy-fermion semiconducting state ensues and in 

the later case, the system remains metallic at low temperatures. Due to the temperaturedependence 

of the electronic correlations, the magnitudes of the hybridization gaps 

decrease with increasing temperatures. The existence of a temperature-dependent lowenergy 

electronic energy scale opens up the possibility that the Born-Oppenheimer 

approximation may fail and that there may be a resonant coupling between the 

phonons and the electronic excitations. It is argued that such a mechanism may be the 

cause of the anomalous temperature-dependence of the phonon spectrum in Pu and the 

anomalous phonon mode observed in α-uranium. 

PD03 

Non-linear conductivity of resistive oxides: truths and myths 

B. - Fisher*, J. - Genossar, L. - Patlagan and G. M. Reisner 

Physics, Technion, Israel 

WITHDRAWN 


PD04 

The modulated spin liquid and hidden order in URu 2Si 2 

Sebastien Burdin 

Bordeaux University, France 

We have shown that near a Kondo breakdown critical point, a spin liquid with spatial 

modulations is likely to be formed. Unlike its uniform counterpart, we find that this 

occurs via a second order phase transition. The amount of entropy quenched when this 

ordering is manifest is of the same magnitude as for an antiferromagnet. Moreover, 

these two states are in direct competition with each other, and at low temperatures they 

are separated by a first order phase transition. This suggests that the modulated spin 

liquid is indeed a viable candidate for the unique phase of matter which is observed 

in the hidden order phase of URu 2Si 2. We investigate the modulated spin liquid 

proposal taking full account of the tetragonal-body-centered lattice structure which 

characterizes URu 2Si 2. We find that the physical quantities predicted from the model 

are in very good qualitative and quantitative agreement with recent experiments, 

including thermodynamic properties, inelastic neutron scattering, and Fermi surface 

measurements. We also present an overview of other f-electron compounds where 

similar phases have been observed. 

Refs. : C. Pepin, M.R. Norman, S. Burdin, and A. Ferraz, Phys. Rev. Lett. 106, 106601 (2011) C. 

Thomas, S. Burdin, C. Pepin, and A. Ferraz, in preparation. 

PD05 

Fermi-surface evolution in Yb-substituted CeCoIn 5 

Joachim Wosnitza 1 *, Andrey Polyakov 1 , Andrea D. Bianchi 2 , S. Blackburn 2 , B. 

Prevost 2 , G. Seyfarth 2 and Michel Cote 2 

1 Hochfeld-Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Germany 

2 Department de Physique and RQMP, Universite de Montreal, Montreal H3C 3J7, 

Canada 

In CeCoIn5, substitution on the rare-earth site has been found to influence the Kondolattice 

coherence and Cooper pairing in a rapid and uniform way. Yb substitution, 

however, shows a different behavior in that Tc and the Kondo-coherence temperature 

do not scale, in contrast to other heavy-fermion compounds. We performed a 

comprehensive dHvA study on Ce1-xYbxCoIn 5. For small Yb concentration, x = 

0.1, the band-structure topology and the ef-fective masses remain nearly unchanged 

compared to CeCoIn 5. This contrasts clearly modified Fermi surfaces and light, almost 

unrenormalized effective masses for x = 0.2 and above. These observations cannot 

explain the heavy-fermion physics observed in specific-heat and resistivity data even 

for high Yb concentrations. Thus, we suggest the existence of heavy quasiparticles with 

short mean free paths, not detectable by dHvA experiments. However, the mechanism 

by which superconductivity can emerge from these charge carriers remains elusive. 

Work done in cooperation with K. Gotze, D. Hurt, Z. Fisk, R. G. Goodrich, I. Sheikin, 

M. Richter. Part of this work was supported by EuroMagNET II (EU contract No. 

228043). 

PD06 

Spin exciton formation inside the hidden order phase of CeB 6 

Alireza Akbari and Peter Thalmeier 

MPI-CPfS, Germany 

The heavy fermion metal CeB6 exhibits hidden order of antiferroquadrupolar (AFQ) 

type below T Q=3.2K and subsequent antiferromagnetic (AFM) order at T N=2.3K. 

It was interpreted as ordering of the quadrupole and dipole moments of a Γ 8 quartet 

of localised Ce 4f 1 electrons. This established picture has been profoundly shaken 

by recent inelastic neutron scattering[1] that found the evolution of a feedback spin 

exciton resonance within the hidden order phase at the AFQ wave vector appears and 

is stabilized by the AFM order. We develop an alternative theory based on a fourfold 

degenerate Anderson lattice model, including both order parameters as particle- 

hole condensates of itinerant heavy quasiparticles. This explains in a natural way 

the appearance of the spin exciton resonance and the momentum dependence of its 

spectral weight, in particular around the AFQ vector and its rapid disappearance in the 

disordered phase. Analogies to the feedback effect in unconventional superconductors 

and Kondo semiconductors are pointed out. 

[1] G. Friemel, et al, Nature Communications 3, 830 (2012). 

[2] A. Akbari and P. Thalmeier, Phys. Rev. Lett. 108, 146403 (2012).

PD07 

Antiferromagnetic fluctuation in hidden order phase of U(Ru,Rh) 2Si 2 

Makoto Yokoyama 1 *, Kenichi Tenya 2 and Hiroshi Amitsuka 3 

1 Faculty of Science, Ibaraki University, Japan 

2 Faculty of Education, Shinshu University, Japan 

3 Graduate School of Science, Hokkaido University, Japan 

The origin of so-called hidden-order (HO) transition observed at To=17.5K in URu 2Si 2 

has been one of the longstanding issues in physics of heavy-fermion systems. In the 

mixed compounds U(Ru1-xRhx) 2Si 2, it is found that a large-moment antiferromagnetic 

(AF) order replaces HO for 0.02≤x≤0.03 via a first-order phase transition, and both 

orders disappear above x≥0.04. To clarify microscopic features of magnetic fluctuation 

in both HO and AF phases, we have performed inelastic neutron scattering experiments 

for U(Ru1-xRhx) 2Si 2 (x≤0.03). At the AF wave vector Q=(1,0,0), the AF excitation 

peak is clearly observed in HO phase for 0≤x≤0.02, but it disappears in the AF phase 

for 0.02≤x≤0.03. The excitation gap at 1.4K is found to be weakly reduced from 2.4meV 

(x=0) to 1.8meV (x=0.015) as x is increased. Temperature variations of the staggered 

susceptibility χ(Q,T) at x=0 estimated from the inelastic-peak intensities show a 

weak enhancement in HO phase and a cusp-like anomaly at To. By doping Rh, the 

enhancement of χ(Q,T) in HO phase becomes pronounced, but a cusp-like anomaly at 

To is reduced. These features indicate that the AF fluctuation develops on the verge of 

the first-order phase boundary in HO phase, while it is suppressed in the AF phase. 

PD08 

Pressure effect on the field-induced ordered phase in heavy fermion 

compound YbCo 2Zn 20 

Tetsuya Takeuchi 1 , Yuki Taga 2 , Shingo Yoshiuchi 2 , Masahiro Ohya 2 , Yusuke Hirose 2 , 

Fuminori Honda 2 , Rikio Settai 2 and Yoshichika Onuki 2 

1 Low Temperature Center, Osaka University, Japan 

2 Graduate School of Science, Osaka University, Japan 

We succeeded in growing high-quality single crystals of heavy fermion compounds 

YbT 2Zn 20 with T = Co, Rh, and Ir, and found a metamagnetic behavior at H m below 

the characteristic temperature Tχmax, where the magnetic susceptibility takes a broad 

maximum. For YbCo 2Zn 20, H m = 6 kOe and Tχmax = 0.32 K, for example. H m and 

Tχmax in these compounds were found to satisfy a universal relation H m (kOe) = 

15Tχmax (K). Recently, we found a field-induced ordered phase (FIOP) above H Q 

= 60 kOe for H // in YbCo 2Zn 20 below T Q = 0.6 K and suggested an antiferroquadrupole 

order for the FIOP. In this work, we performed pressure experiments in 

YbCo 2Zn 20 with H // in order to study the pressure effect on the FIOP as well 

as the pressure-induced antiferromagnetic phase (PIAF) above P c~2 GPa. When the 

pressure is applied, the transition field H Q was found to decrease with increasing 

pressure up to around P c. Above P c, there is a pressure region where the PIAF and 

FIOP were observed under the same pressure. In order to investigate how the FIOP 

disappears or merges with the PIAF, further pressure experiments are in progress under 

higher pressures. 

PD09 

29Si-NMR Study of antiferromagnet CeRh 2Si 2 using single crystals 

Hironori Sakai, Yo Tokunaga, Shinsaku Kambe, Yuji Matsumoto, Tatsuma D Matsuda 

and Yoshinori Haga 

Advanced Science Research Center, Japan Atomic Energy Agency, Japan 

29Si-NMR Study of antiferromagnet CeRh 2Si 2 has been performed using single 

crystals. Heavy fermion material CeRh 2Si 2 is known to be an antiferromagnet with 

strong uniaxial magnetic anisotropy along the crystallographic c-axis under ambient 

pressure. From our measurements of Knight shifts and relaxation rates, the spin 

dynamics of this material have been investigated. At ambient pressure, as seen in the 

static susceptibility, the Ising-type antiferromagnetic spin fluctuations along the c-axis 

has been found to be enhanced. In this presentation, we will show our latest data and 

discuss about the anisotropy of hyperfine couplings and spin dynamics. 

PD10 

PD11 

PD12 


Bulk compressibility of orthorhombic YbFe 2Al 10-type CeRu 2Al 10 

Yukihiro Kawamura 1 *, Kazuki Matsui 1 , Keiichi Yamamoto 1 , Yusuke Hori 1 , Junichi 

Hayashi 1 , Keiki Takeda 1 , Chihiro Sekine 1 and Takashi Nishioka 2 

1 Muroran Institute of Technology, Japan 

2 Kochi University, Japan 

Orthorhombic YbFe 2Al 10-type CeRu 2Al 10 shows antiferromagnetic transition at T0~27 

K[1]. This antiferromagnetic transition has various unusual features. One of them is 

reduced magnetic moment; The neutron experiment reveals that the magnetic moment 

of Ce in the ordered phase on CeRu 2Al 10 is 0.34 μB/Ce[2]. Considering this reduced 

magnetic moment, T0 should be much lower. Another unusual feature is abrupt 

disappearance of antiferromagnetic transition by applying pressure[3]. Structural 

modulation might be occurred at around the pressure of disappearing T0. Thus, we 

performed synchrotron X-ray study at room temperature under pressure by using 

diamond anvil pressure cell and investigated bulk compressibility of CeRu 2Al 10. We 

revealed that lattice parameters a, b and c monotonically decreases with increasing 

pressure, which indicates that there is no structural modification up to 9.2 GPa at room 

temperature. We also revealed that the decrease ratio of b is smaller than that of a and c. 

[1] A. M. Strydom, Physica B 404 (2009) 2981-2984 [2] D. D. Khalyavin et al., Phys. Rev. B 82 

(2010) 100405 [3] T. Nishioka et al., J. Phys. Soc. Jpn 78 (2009) 123705 

Ultrasound measurements on the skutterudite compound SmOs 4P 12 

Yoshiki Nakanishi 1 *, Gen Koseki 1 , Dai Tamura 1 , Kohei Kurita 1 , Takeshi Saito 1 , 

Minoru Koseki 1 , Mitsuteru Nakamura 1 , Masahito Yoshizawa 1 , Masahito Yoshizawa 1 , 

Yuya Koyota 2 , Chihiro Sekine 2 and Takehiko Yagi 3 

1 Iwate University, Japan 

2 Muroran Institute of Technology, Japan 

3 ISSP The University of Tokyo, Japan 

We present an ultrasound study on the Sm-based filled skutterudite compound SmOs 4P 12 

for the first time. The measurements were performed on a polycrystalline sample using 

a phase-sensitive detection technique. The ternary compound SmOs 4P 12 were prepared 

at high temperature and high pressures using a wedge-type cubic-anvil high-pressure 

apparatus. SmOs 4P 12 exhibits antiferromagnetic ordering below 4.5 K. A clear decrease 

was observed at 4.5 K in the temperature dependence of both longitudinal and transverse 

elastic constants. However, less or no elastic softening toward the transition temperature 

was observed in the both elastic constants. Absence of the precursor behavior reminds us 

a multipolar ordering, possibly octupolar ordering observed in the isostructural system 

SmRu 4P 12, reported previously by our group. The transition is robust against the external 

magnetic field. To be more interesting, the elastic constants show a minimum around 180 

K, possibly related to a rattling motion due to weakly bounded Sm ion in an oversized P 

cage. We argue a low-lying degenerated levels derived from 4f-multiplets ground state of 

Sm ion split by crystalline electric field effect in SmOs 4P 12. Furthermore, we discuss the 

phononic properties in comparison with other isostructral systems which include an ionic 

degrees of freedom of the rattling motion. 

YbRh2Si2: Fermi surface and crystal-field splittings of a heavy- 

Fermion compound 

Steffen Danzenbacher 1 , Denis V. Vyalikh 1 , Kurt Kummer 2 , Yuri Kucherenko 3 , 

Cornelius Krellner 4 , Christoph Geibel 5 , Serguei L. Molodtsov 6 , Ming Shi 7 , Luc 

Patthey 7 and Clemens Laubschat 1 * 

1 

Institut fur Festkorperphysik, Technische Universitat Dresden, D-01062 Dresden, 

Germany 

2 

European Synchrotron Radiation Facility, FR-38043 Grenoble Cedex, France 

3 

Institute of Metal Physics, National Academy of Sciences of Ukraine, UA-03142 

Kiev, Ukraine 

4 

Max-Planck-Institut fur Chemische Physik fester Stoffe, D-01187 Dresden, Germany 

5 

Max-Planck-Institut fur Chemische Physik fester Stoffe, D-01187 Dresden, Germany 

6 

European XFEL GmbH, , D-22671 Hamburg, Germany 

7 

Swiss Light source, Paul Scherrer Institute, CH-5232 Villingen-PSI, Switzerland 

YbRh 2Si 2 is a well known heavy Fermion system with a Kondo temperature of 25 K and a mean valence of 2,9. 

Due to the mixing of 4f14 and 4f13 configurations in the ground state, the 4f13 state is reproduced as a final 

state in a photoemission experiment allowing for direct observation of near ground state properties. Angleresolved 

photoemission spectra reveal a general dispersion of the 4f13 state with a Fermi-level crossing around 

the Γ-point. A clear wave-vector dependence of the crystal-field split states is observed that leads to a variation 

of the energy splittings across the Brillouin zone and even to an interchange of the sequence of states. The bulk 

Fermi surface reveals strong similarities with the one expected for a stable trivalent compound, but is slightly 

larger, reveals strong 4f character, and deviates from LDA results by a larger region without states around the 

Γ-point. These properties are well described in the framework of a simple fd-hybridization model. 




PD13 


Single crystal growth and various electronic states in Yb-based 

compounds 

Yusuke Hirose 1 *, Shingo Yoshiuchi 1 , Naoto Nishimura 1 , Jyunya Sakaguchi 1 , Kentaro Enoki 1 , Ken 

Iwakawa 1 , Yasunao Miura 1 , Tetsuya Takeuchi 2 , Kiyohiro Sugiyama 1 , Fuminori Honda 3 , Etsuji 

Yamamoto 4 , Yoshinori Haga 4 , Masayuki Hagiwara 5 , Koichi Kindo 6 , Rikio Settai 1 and Yoshichika Onuki 1 


2 Low Temperature Center, Osaka University, Japan 

3 Graduate School of Engineering Science, Osaka University, Japan 



6 ISSP, University of Tokyo, Japan 

To clarify the various electronic states of Yb compounds, we grew single crystals of several Yb compounds such 

as YbTIn 5 (T : Co, Rh, Ir), YbCoGa 5, YbT 2Zn 20 (T : Co, Rh, Ir) and Yb 2Pt 2Pb by the flux method, and YbPdGe 

and YbPd 5Al 2 by the Bridgman method. YbTIn 5 and YbCoGa 5 are Pauli paramagnets, but the cyclotron 

effective mass of YbCoGa 5 is by four times larger than that of YbTIn 5. YbT 2Zn 20 (T : Co, Rh, Ir) compounds are 

heavy fermion compounds. In fact, the electronic specific heat coefficient γ is 8000 mJ/K2•mol in YbCo 2Zn 20, 

very close to the quantum critical point. YbPdGe is an Ising-type ferromagnet with the Curie temperature TC = 

11.4 K and a saturated magnetic moment μs = 1.7 μB/Yb, but possesses a relatively large value of γ = 150 mJ/ 

K2•mol. Yb 2Pt 2Pb is a Shastry-Sutherland-type antiferromagnet with the Neel temperature TN = 2.1 K. Finally, 

YbPd 5Al 2 of which the analogue is a heavy fermion superconductor NpPd 5Al 2 is a well-known heavy fermion 

superconductor[1] is an antiferromagnet with a very small Neel temperature TN = 0.19 K. 

[1] D. Aoki et al. : J. Phys. Soc. Jpn. 76 (2007) 063701. 

PD14 

Physical properties under pressure in a heavy fermion superconductor 

CeIrIn5 Naofumi Aso 1 *, Yuki Tamaki 1 , Yoshinao Takaesu 1 , Masato Hedo 1 , Takao Nakama 1 , 

Kiyoharu Uchima 2 , Kazuyuki Matsubayashi 3 , Yoshiya Uwatoko 3 , Yusuke Ishikawa 4 , 

Kazuhiko Deguchi 4 and Noriaki K. Sato 4 

1 

Faculty of Science, University of the Ryukyus, Japan 

2 

General Education, Okinawa Christian Junior College, Japan 

3 

ISSP, University of Tokyo, Japan 

4 

Graduate School of Science, Nagoya University, Japan 

CeIrIn 5 is a heavy fermion superconductor with Tc = 0.4 K and the electronic specific heat γ = 700 mJ/(K2•mol) 

[1]. To investigate the nature and the pressure effect of the Kondo effect on CeIrIn5, electrical resistivity ρ and 

magnetization M under pressure in CeIrIn 5 have been measured using the single-crystalline CeIrIn 5 which 

were grown by the In-flux method. The temperature dependence between 2.0 K and 300 K of the a-axis and 

c-axis electrical resistivity ρ of CeIrIn 5 under pressure up to 8.0 GPa, which were obtained using a cubic anvil 

device, exhibits the typical dense Kondo behavior: on cooling from room temperature at P = 1.0 GPa, the ρ 

increases and shows a maximum of the coherence peak, and then goes down into the coherent Kondo state. 

We also find that the coherence peak moves to higher temperatures with pressure, indicating that the Kondo 

temperature of CeIrIn 5 increases by applying the pressure. In the conference, we will also report the M data 

under pressure up to 1.5 GPa and compare the ρ data with our recent thermoelectric power S measurements, 

which exhibit a large positive value up to 90 μV/K with a sharp maximum in its temperature dependence. [2] 

[1] C. Petrovic et al., Europhys Lett., 53, 354, (2001). [2] Y. Takaesu et al., J. Phys.: Conf. Series, 273, 012058, (2011). 

PD15 

Periodic Anderson model with correlated conduction electrons 

Imre Hagymasi*, Kazumasa Itai and Jeno Solyom 

Theoretical Solid State Physics, Wigner Research Centre for Physics, Hungarian 

Academy of Sciences, Hungary 

We investigate the so-called periodic Anderson-Hubbard model with the aim to 

understand the role of interaction between conduction electrons in the formation of the 

heavy-fermion and mixed-valence states [1]. We perform variational calculation using 

the Gutzwiller wave function and exact diagonalization of the Hamiltonian for short 

chains. The f-level occupancy and the renormalization factor of the quasiparticles are 

calculated as a function of the energy of the f-orbital for a wide range of the interaction 

parameters. The results obtained by the two methods are in reasonably good agreement 

for the periodic Anderson model. The agreement remains even for the Anderson- 

Hubbard model, except for the half-filled case. We find that due to this interaction the 

energy range of the bare f-level, where heavy-fermion behavior can be observed, shifts 

and widens. The Gutzwiller method indicates a robust transition from Kondo insulator 

to Mott insulator in the half-filled model, while this interaction enhances the quasiparticle 

mass when the filling is close to half filling. 

[1] I. Hagymasi, K. Itai and J. Solyom Periodic Anderson model with correlated conduction 

electrons: variational and exact diagonalization study, arXiv::1106.4999 


PD16 

Thermoelectric study of the metamagnetic behavior in YbCo 2Z 20 

Yo Machida 1 , Tohru Ikeura 1 , Koichi Izawa 1 *, Shingo Yoshiuchi 2 , Fuminori Honda 2 , 

Rikio Settai 2 and Yoshichika Onuki 2 

1 Department of Physics, Tokyo Institute of Technology, Japan 

2 Department of Physics, Osaka University, Japan 

Despite the intensive studies on the metamagnetic behavior which has been found 

in a wide variety of heavy fermion materials such as CeRu 2Si 2, CeCu 6, and UPt 3, 

the origin remains under debate. The recent discovered heavy fermion compound 

YbCo 2Zn 20 exhibits the metamagnetic behavior under unexpectedly small magnetic 

field ~ 0.6 T, providing a new platform for elucidation of the metamagnetism. We 

have addressed this issue by means of the thermoelectric transport, which has been 

a promising probe to unveil the low-energy itinerant excitations and the electronic 

transformation across the metamagnetic transition. We measured the Seebeck and 

Nernst coefficients of YbCo 2Zn 20 down to very low temperature. Remarkably, we 

found a huge Seebeck coefficient ~ -250 μV/K^2 under zero field, as an indication of 

the “super” heavy fermion state. Moreover, on passing through the metamagnetic field 

the Seebeck coefficient shows dramatic suppression, being distinct from that observed 

in CeRu 2Si 2 in which the Seebeck coefficient is largely enhanced at the metamganetic 

field. In our presentation, we will discuss the thermoelectric response of YbCo 2Zn 20 

and its implication to the metamagnetism. The comparison to the other metamagnetic 

materials will be also made. 

PD17 

Raman scattering study of the hidden order state of URu2Si2 Jonathan Buhot 1 , Marie-aude Measson 1 *, Yann Gallais 1 , Maximilien Cazayous 1 , Alain 

Sacuto 1 and Dai Aoki 2 

1 

Laboratoire Materiaux et Phenomenes Quantiques, UMR 7162 CNRS, Universite 

Paris Diderot, France, France 

2 

SPSMS, UMR-E CEA / UJF-Grenoble 1, INAC, 38054 Grenoble, France, France 

For over 25 years, researchers attempt to understand the microscopic origin of the 

Hidden Order that appears below T0=17.5 K in the heavy fermions compound 

URu 2Si 2. Mainly, optical measurements on URU 2Si 2 are far-infrared reflectance 

experiments[1,2]. Only few Raman scattering studies have been performed [3,4] and 

only for c axis. We have studied URu 2Si 2 for both axes, down to low temperature 

(2K). We have probed the phononic and electronic properties and their interaction. 

Softening of phonon modes together with Fano-shape were observed, implying that 

a phonon-electron coupling is at play. At low energy, electronic Raman signal shows 

either fluctuations or more conventional Drude shape for different symmetry. We have 

studied both signals through the Hidden Order temperature. 

D.A. Bonn et al., PRL 61 1305 (1988), J. Levallois et al., PRB 84, 184420 (2011) S. Cooper et al., 

PRB 36 5743 (1987), D. Lampakis et al., PHYSICA B 378-380, 578 (2006) 

PD18 

The evolution of superconductivity and magnetism in Pd-doped 

CeRhIn 5 and Ce 2RhIn 8 

Marie Kratochvilova*, Klara Uhlirova, Jiri Prchal, Alexandra Rudajevova, Jeroen 

Custers and Vladimir Sechovsky 

Department of Condensed Matter Physics, Faculty of Mathematics and Physics, 

Charles University, Czech Republic 

CeRhIn 5 and Ce 2RhIn 8 are heavy fermion antiferromagnets. Unconventional superconductivity can be 

induced by hydrostatic pressure or doping [1,2]. By contrast, Ce 2PdIn 8 is a heavy fermion superconductor 

(Tc=0.7K) at ambient pressure. We have examined the influence of Pd doping in single crystals of CeRh 1xPdxIn 

5 and Ce 2Rh 1-xPdxIn 8. Since the synthesis of Ce 2PdIn 8 is connected either to intergrowth of CeIn 3 or 

variation of critical temperature, growth conditions were studied by differential thermal analysis. By this, we 

have succeeded in obtaining high-quality single crystals free of CeIn 3 and with a critical temperature Tc~0.7K. 

The crystals have been subjected to specific heat, resistivity and AC susceptibility measurements. In addition, 

resistivity experiments under hydrostatic pressures up to 3GPa were performed. Surprisingly, at ambient 

pressure the Neel temperature of CeRh 1-xPdxIn 5 has only slightly decreased with increasing Pd content. And 

moreover, the pressure influence on magnetism in CeRh 0.75Pd 0.25In 5 does not significantly differ from CeRhIn 5. 

Contrary, the superconducting transition increases significantly compared to its 115-counterpart. The less twodimensional 

Ce 2Rh 1-xPdxIn 8 behaves different. Here, the antiferromagnetic ordering is immediately lowered 

upon Pd substitution and vanishes completely at x~0.35 already. The obtained magnetic field-temperature 

phase diagrams will be discussed in context of the physical properties of other CenTIn3n+2 compounds. 

[1] H. Hegger et al., Phys. Rev. Lett. 84, 4986 (2000). [2] M. Nicklas et al., Phys. Rev. B 67, 020506 (2003).

PD19 

Magnetic phase diagram of the new heavy fermion compound 

Ce2PtIn81 Marie Kratochvilova 1 *, Klara Uhlirova 1 , Jiri Prchal 1 , Ivana Cisarova 2 , Jeroen Custers 1 

and Vladimir Sechovsky 1 

1 

Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles 

University, Czech Republic 

2 

Department of Inorganic Chemistry, Faculty of Science, Charles University, Czech Republic 

CenTmIn 3n+2m (n=1,2; m=1; T=transition metal) type compounds are subject of intense interest in the 

condensed-matter community [1]. They are predestinated to investigate the interplay between magnetism 

and superconductivity. Recently, two new compounds from this heavy fermion family have been found. 

Ce 2PdIn 8 is an ambient pressure superconductor while CePt 2In 7 orders antiferromagnetically [2]. We report 

on the existence of a new compound Ce 2PtIn 8. Similar to Ce 2PdIn 8, the synthesis of Ce 2PtIn 8 is rather 

complicated. However, from our studies of solution growth of Ce 2PdIn 8 and the support by differential 

thermal analysis, optimal conditions for growing Ce 2PtIn 8 were deduced. Single-crystal X-ray diffraction 

confirmed that Ce 2PtIn 8 crystallizes in Ho 2CoGa 8-type structure with lattice parameters a=4.699A and 

c=12.185A. We will present specific heat, resistivity (ambient and under hydrostatic pressure) and 

magnetization measurements. Ce 2PtIn 8 orders magnetically below 2.1K. A second transition, likely into 

a magnetic commensurate ordering, is observed just below at 2K. Contrary to Ce 2RhIn 8, the magnetic 

transitions shift to lower temperatures in applied magnetic field along both principal crystallographic 

axes suggesting different character of magnetic ordering. Specific heat measurements reveal an enhanced 

Sommerfeld coefficient (γ~740 mJ/mol.K2). The magnetic field-temperature phase diagram will be 

discussed in the context of superconductivity and magnetism evolution in related compounds. 

[1] Ch. Pfleiderer, Rev. Mod. Phys. 81, 2009 [2] E. D. Bauer, et al., Phys. Rev. B 81, 180507 (2010) 

PD20 

Coexistence and competition of superconductivity, magnetism and 

charge density waves in rare-earth tri-telluride TbTe 3 

Kazuhiko Deguchi, Hiroaki Iwase, Yuya Imai, Koji Yamamoto and Noriaki Sato 

Department of Physics, Graduate School of Science, Nagoya University, Japan 

Rare-earth tri-telluride RTe 3 (R = Y, La-Sm, Gd-Tm) forms a weakly orthorhombic 

crystal lattice, consisting of alternating double layers of corrugated double RTe layers 

and nominally square-planar Te sheets. The RTe layers are responsible for magnetism 

while the square Te sheets contribute to strongly anisotropic conduction. Interestingly, 

the two-dimensional conduction bands originating from Te-5px and 5py orbitals give 

rise to Fermi surface nesting, and this hidden one-dimensionality leads to a charge 

density waves (CDW) with a high transition temperature. Because of this intriguing 

feature, RTe 3 attracts great interest in recent years. TbTe 3 has localized 4f electrons, 

and exhibits successive phase transitions of magnetic origin, which all coexist with the 

CDW. Surprisingly, superconductivity emerges under high pressure. The question is 

whether the superconductivity coexists or competes with the other long range orders. 

Therefore, we investigated the long-range orders by the electrical resistivity and ac 

magnetic susceptibility at high pressures up to 8 GPa and at low temperatures down 

to 2 K using a constant-load cubic-anvil cell with single crystalline samples that were 

grown from Te-fluxes. We found that the antiferromagnetism survives even at the 

highest pressure of the present experiment. We also confirmed the emergence of the 

superconductivity at high pressures. 

PD21 

Magnetic properties of Ce 3Rh 4Sn 13 and Ce 3Co 4Sn 13; a comparative 

study 

Andrzej Slebarski*, Marcin Fijalkowski and Jerzy Goraus 

Institute of Physics, University of Silesia, Poland 

We report on the electronic structure (XPS) and basic thermodynamic properties 

of Ce 3Rh 4Sn 13 and Ce 3Co 4Sn 13 and the reference La-based compounds. The both 

compounds were classified as a heavy fermion materials with extremely large low 

temperature electronic specific heat C/T [1] of about 4 J/molK2. The data show that 

either Ce 3Rh 4Sn 13 or Ce 3Co 4Sn 13 are very sensitive to applied magnetic fields and 

exhibit a cross-over from magnetically correlated state to a single impurity state, when 

the applied magnetic field increases. We noted that the low temperature properties are 

dependent on the stoichiometry of the sample. We also present and discuss the low 

temperature properties of Ce 3Co 4Sn 13 doped with La. 

1] U. Kohler et al. J. Phys.:Condens. Matter 19 (2007) 386207 

PD22 

PD23 

PD24 


Thermoelectric properties of Kondo semiconductor CeRu 4As 12 

prepared under high pressure 

Chihiro Sekine 1 *, Tomokazu Kawata 1 , Yukihiro Kawamura 1 and Takehiko Yagi 2 

1 Graduate School of Engineering, Muroran Institute of Technology, Japan 

2 Institute for Solid State Physics, The University of Tokyo, Japan 

The filled skutterudite compound CeRu 4As 12 exhibits a hybridization gap insulating 

state, with a small activation energyΔ/kB of 50K [1]. We report further results for 

CeRu 4As 12 prepared under high pressure (4GPa). Thermoelectric power and thermal 

conductivity measurements have been performed on this material. The temperature 

dependence of thermoelectric power for CeRu 4As 12 shows two peaks (around 80K, 

200K). The phenomena could be related to Kondo behavior at high temperature and 

hybridization-gap-formation process at low temperature. 

[1] C. Sekine et al., J. Mag. Mag. Mater., 310 (2007) 260. 

Single crystal growth and physical properties of UT 2Al 20 (T=transition 

metal) 

Yuji Matsumoto 1 , Tatsuma D Matsuda 1 , Naoyuki Tateiwa 2 , Etsuji Yamamoto 1 , 

Yoshinori Haga 1 and Zachary Fisk 3 

1 advanced science research center, Japan atomic energy agency, Japan 

2 Japan atomic energy agency, Japan 

3 University of California, USA 

Many anomalous physical properties have been observed in RT 2X 20 (R=Rare metal, 

T=transition metal, X=Al, Zn) system. For example, the quadrupolar order takes place 

in PrT 2X 20 system, and the extreme heavy fermion state takes place in YbCo 2Zn 20. 

In the uranium analogue, for example, UT 2Al 20 is worth investigating because the 

extended 5f wave function in uranium would lead to peculiar features due to strong 

hybridization. Therefore we have studied single crystal growth and physical properties 

of UT 2Al 20. The sample preparation is performed by using Al-self flux method. We 

have succeeded to prepare the single crystal of UT 2Al 20 (T=Ti, Nb). We are going to 

present about the physical properties of the prepared samples in the <strong>Conference</strong>. 

Anisotropic c-f hybridization in a Kondo semiconductor CeFe2Al10 Yuji Muro 1 , Keisuke Yutani 2 , Jumpei Kajino 2 , Takahiro Onimaru 2 and Toshiro Takabatake 3 

1 

Liberal Arts and Sciences, Toyama Prefectural University, Kurokawa 5180, Imizu 939- 

0398, Japan 

2 

AdSM, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8530, Japan 

3 

AdSM and IAMR, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739- 

8530, Japan 

We report anisotropic properties of a Kondo semiconductor CeFe 2Al 10. This compound is the non-magnetic 

counterpart of Kondo semiconductors CeT 2Al 10 (T=Ru and Os) that exhibit an unusual antiferromagnetic 

transition at about 28 K[1-5]. The magnetic susceptibility for B//a, χa(T), shows a broad peak at 70 K due 

to the strong c-f hybridization. The anisotropy in χ, χa>χc>χb, is in common with those for T = Ru and Os. 

Electrical resistivity ρ(T) has a broad maximum at 45, 35 and 110 K for I//a, I//b and I//c, respectively. Below 

20 K, ρ’s along all axes show an upturn due to the opening of a pseudo gap. Thermopower S(T) also shows 

a maximum at 190, 150 and 200 K for a-, b- and c-axis, respectively. The temperatures at the maximum in ρ 

and S suggest the anisotropy of c-f hybridization strength Vc>Va>Vb in CeFe 2Al 10 as reported in the study 

of optical conductivity[6]. Furthermore, only Sc(T) changes the sign from positive to negative at 100 K on 

cooling and shows a minimum at 50 K. The negative minimum was also observed in Sc(T) for T=Ru and 

Os[7]. This behavior indicates the development of antiferromagnetic correlation along the c-axis in CeT2Al10. 

[1] Y. Muro et al. J. Phys. Soc. Jpn. 78 (2009) 083707. [2] T. Nishioka et al. J. Phys. Soc. Jpn. 78 

(2009) 123705. [3] Y. Muro et al. Phys. Rev. B 81 (2010) 214401. [4] D. D. Khalyavin et al. Phys. 

Rev. B 82 (2010) 100405R. [5] D. T. Adroja et al. Phys. Rev. B 82 (2010) 104405. [6] S. Kimura et 

al. J. Phys. Soc. Jpn. 80 (2011) 033702. [7] H. Tanida et al. J. Phys. Soc. Jpn. 79 (2010) 063709. 




PD25 


Cu-NMR studies of heavy-Fermion compound CeCu 6 under high 

magnetic fields 

Keisuke Kuroda, Kyohei Morita, Hisashi Kotegawa, Hitoshi Sugawara and Hideki 

Tou* 

Department of Physics, Kobe University, Japan 

It is known that the intermetallic compound CeCu 6 is a heavy fermion system showing 

a huge specific heat coefficient γ ~ 1600 mJ / K2 mol, without magnetic order or 

superconductivity at low temperatures down to 10 mK[1,2]. The electric resistivity 

shows characteristic temperature dependence of ? logT above 10 K, which is ascribed 

to the Kondo effect, and it has a maximum around 10 K. No detailed NMR results have 

been reported yet because of a drawback of the complicated Cu NMR spectrum due to 

a peculiar orthorhombic crystal structure. We have carried out Cu-NMR measurements 

to clarify the heavy fermion state of a single crystal CeCu 6 under several magnetic 

fields. We have measured Knight shift and the nuclear spin-lattice relaxation time T1 

under magnetic fields up to 15 T along the a-axis and c-axis in the temperature range of 

100-1.5 K. At low temperatures, the Cu-NMR Knight shifts are suppressed as magnetic 

field increases. Simultaneously, 1/T1 is suppressed. These features are understood by 

the concept that the heavy fermion state in CeCu 6 is formed through Kondo effect. We 

will report detailed field dependence of the heavy fermion state of CeCu 6 for the first 

time. 

[1] Y. Onuki, et al.: JPSJ 53 (1984) 1210 [2] Y. Onuki, et al.: JMMM 63-64 (1987) 281 

PE01 

The underscreened Anderson lattice : A model for uranium 

compounds. 

Peter S Riseborough 1 *, Sergio Magalhaes 2 and Bernard Coqblin 3 

1 Physics, Temple University, USA 

2 Inst. Fis., Univ. Fed. Fluminense, Rio de Janeiro, Brazil 

3 L.P.S., CNRS-Universite Paris-Sud, 91405 Orsay, France 

We present a model based on the Underscreened Anderson Lattice (UAL) with two 

5f electrons per site to account for the Kondo-ferromagnetism co-existence observed 

in some actinide compounds. The UAL model allows a description of the decrease of 

the number of f-electrons and we present a calculation which explains the pressure 

dependence observed in some Uranium compounds and particularly in Uranium 

monochalcogenides. On the other hand, we have developed a novel type of phase 

transition within the UAL model and we suggest that this model might describe the 

“Hidden Order” transition in URu 2Si 2. The gaps that appear in the electronic dispersion 

relations of bands of different orbital character are in agreement with experimental 

photoemission results. 

PE02 

Transport properties of intermetallic compounds RCoGe 2 (R = Ce and 

La) 

Yung-kang Kuo 1 *, P. C. Chang 2 and C. S. Lue 3 

1 National Dong Hwa University, Department of Physics, Taiwan 

2 Department of Physics, National Dong Hwa University, Taiwan 

3 National Cheng Kung University, National Dong Hwa University,, Taiwan 

The electronic and magnetic properties of the cerium-based ternary intermetallic 

compound compounds with the general formula CeMSi 2 (M = transition metals) 

has been of considerable interest recently. Among those compounds, CeCoGe 2 is of 

particular interest due to its peculiar physical properties, such as it has a rather high 

Kondo temperature TK ~ 250 K, and it is the first Kondo system clearly interpreted by 

the Coqblin-Schrieffer model with j = 5/2. In this study, measurements of the electrical 

resistivity, Seebeck coefficient, and thermal conductivity on CeCoGe 2 have been 

performed in the temperature range 10 - 300 K to investigate the electronic structure. 

For comparison, the nonmagnetic counterpart LaCoGe 2 has also been studied. It is 

found that CeCoGe 2 exhibits a broad maximum in Seebeck coefficient at about 75 

K, at which the sudden drop in electrical resistivity occurs. This is a typical behavior 

commonly seen in Ce-based Kondo lattice compounds. A theoretical attempt was made 

and found that the electrical ransport and thermoelectric properties of CeCoGe 2 can be 

well described by a two-band model with reliable physical parameters. On the other 

hand, both electrical resistivity and Seebeck coefficient show a typical metallic-like 

behavior for the nonmagnetic LaCoGe 2. 


PE03 

The lattice Kondo effect - A fabric for superconducting correlations? 

Oliver Bodensiek 1 *, Thomas Pruschke 1 and Rok Zitko 2 

1 Department of Physics, University of Goettingen, 37077 Goettingen, Germany 

2 Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia 

Although the simple Kondo lattice model constitutes one of the paradigms for 

understanding the physics of heavy-fermion materials, a reliable theoretical 

investigation of superconductivity in this model is still lacking. We present results 

based on the dynamical mean-field approximation in combination with the numerical 

renormalization group as impurity solver. While superconducting order is commonly 

not expected for a correlated lattice model without additional bosonic degrees of 

freedom, we observe strong superconducting order in the plain Kondo lattice model 

away from half filling. The possible origin of this superconducting order is discussed 

in view of the frequency dependence of the order parameter. In addition, close to half 

filling we find this ordered phase to appear most pronounced in the vicinity of the 

antiferromagnetic quantum critical point. Since a characterization of quantum criticality 

within dynamical mean-field theory is not possible, we rather discuss questions of 

principle such as the actual nature of the ordered states, that is, local moment or heavyfermion 

physics. The latter issue is of considerable interest addressing the question 

whether the ordered states stay in direct competition or even cooperate with the 

coherent Kondo effect in the lattice. 

PE04 

Lifshitz transition with interactions in high magnetic fields: application 

to CeIn 3 

Pedro Schlottmann* 

Department of Physics, Florida State University, USA 

The Neel ordered state of CeIn 3 is suppressed by a magnetic field of 61 T at 

ambient pressure. There is a second transition at ~45 T, which has been associated 

with a Lifshitz transition. Skin depth measurements indicate that the transition is 

discontinuous as T -> 0 and that the transition has a weak pressure dependence until 

it merges with the Neel transition. We study the effects of Landau quantization and 

interaction among carriers on a Lifshitz transition. The Landau quantization leads 

to quasi-one-dimensional behavior for the direction parallel to the field. Repulsive 

Coulomb interactions give rise to a gas of strongly coupled carriers. The density 

correlation function is calculated for a special long-ranged potential [1]. For the lowest 

Landau level the problem can be mapped onto the interacting one-dimensional electron 

gas. It is concluded that in CeIn 3 (a) an electron or hole pocket is being emptied as a 

function of field and (b) in the ground state the pocket is emptied in a discontinuous 

fashion. This discontinuity is gradually smeared by the temperature in agreement with 

the skin depth experiments. Work supported by the Department of Energy under grant 

DE-FG02-98ER45707. 

[1] P. Schlottmann, Phys. Rev. B 83, 115133 (2011). 

PE05 

Dynamical mean-field theory of indirect exchange between magnetic 

adatoms on metallic surfaces 

Irakli Titvinidze*, Andrej Schwabe, Niklas Rother and Michael Potthoff 

I. Institute of theoretical physics, University of Hamburg, Germany 

Two magnetic impurities on a metallic substrate surface experience the Ruderman- 

Kittel-Kasuya-Yosida (RKKY) exchange interaction. This indirect non-local magnetic 

exchange competes with the local Kondo effect. While the latter is described in 

principle exactly within single-site dynamical mean-field theory, the effects of the 

RKKY coupling are taken into account approximately only. Here, this is demonstrated 

by comparing the DMFT results with numerically exact data obtained by the densitymatrix 

renormalization group for a one-dimensional model with two Anderson 

impurities. With the two-site DMFT, we also benchmark a simplified DMFT variant. 

Varying the inter-impurity distance d and the local exchange coupling J, different 

parameter regimes with dominating Kondo physics or with dominating RKKY 

interaction are studied. For the Kondo regime, our calculations show that DMFT is 

able to reliably describe magnetic nanostructures on metallic surfaces. The prospects of 

DMFT (and two-site DMFT) as a reliable approach to study nanomagnetism of more 

complex RKKY-interacting systems are discussed.

PE06 

Kondo effect near the Van Hove singularity in biased bilayer graphene 

Stanislaw Lipinski* and Damian Krychowski 

Institute of Molecular Physics, Polish Academy of Sciences, Poland 

We study Kondo impurity in a bilayer graphene with Bernal stacking for adatom 

adsorbed on the outside of the bilayer or intercalated between the two graphene layers. 

The density of states (DOS) close to the gap diverges as the square root of energy - 

Van Hove singularity (VHS). The system is modeled by the generalized Anderson 

hamiltonian with bilayer described by Hubbard model. The many-body problem is 

studied within the mean field Kotliar-Ruckenstein slave boson approach for SU(2) 

and SU(4) symmetries. We examine the impact of tuning the Fermi level (EF) through 

the VHS. Increase of the DOS at EF increases hybridization of the impurity, what 

moves the system towards mixed valence regime or even completely suppresses the 

many body peak of DOS. Additionally a competitive influence of magnetic instability 

is analyzed. Crossing of the Fermi level with a Van Hove singularity leads to weak 

ferromagnetism of the bilayer graphene with strong spin polarization at EF. The spin 

symmetry is broken, what for the case of spin-orbital degeneracy results in a crossover 

from SU(4) Kondo effect to SU(2) and in the case of only spin degeneracy it leads to a 

strong suppression of SU(2) Kondo effect. 

PE07 

Indirect exchange between magnetic atoms on surfaces: From two 

impurities to diluted chains 

Andrej Schwabe*, Irakli Titvinidze, Daniel Gutersloh, Anke Braun and Michael 

Potthoff 

I. Institute of theoretical physics, University of Hamburg, Germany 

Magnetic atoms on metallic surfaces are subject to the competition between Kondo 

screening and indirect magnetic (RKKY) exchange. To study the crossover of the 

magnetic properties from the case of a single or two magnetic adatoms to the limit 

of a dense chain of indirectly coupled adatoms, we model the metal surface as a onedimensional 

tight-binding system and apply the density-matrix renormalization group 

(DMRG) to the resulting Kondo model. The case of three magnetic atoms turns out 

to be particularly interesting as finite-size gaps are found to qualitatively affect the 

balance between Kondo physics and RKKY. With the transition from the diluted case 

with a few magnetic atoms to the dense chain with all atoms RKKY-coupled ferro- 

or antiferromagnetically, magnetic long-range order becomes possible. The resulting 

phase diagram is studied in the weak (RKKY) but also in the strong-coupling (Kondo) 

limit. Besides DMRG we employ real-space dynamical mean-field theory (R-DMFT) 

in addition and thereby extend the results to higher dimensions. 

PE08 

ESR study of hybridization in some undoped Yb-based alloys 

Vladimir Ivanshin*, Tatyana Litvinova and Eduard Gataullin 

Institute of Physics, Kazan University, Russia 

The hybridization between a wide conduction band and correlated f-electrons localized 

at lattice sites is investigated using method of electron spin resonance (ESR) in some 

dense heavy-fermion compounds. ESR signals arise here both from the local moment 

spins and conduction electrons (CE) due to the strong electronic correlations because 

of the hybridization between 4f-electrons and CE in the presence of ferromagnetic 

(FM) fluctuations [1]. We review very recent ESR experiments in several undoped Ybbased 

intermetallics [2, 3] and discuss the role of chemical composition, Kondo effect, 

anisotropy, and RKKY interactions for the ESR linewidth. It is shown that an increase 

of the Kondo interaction and FM correlations leads to a stronger hybridization and an 

essential ESR line narrowing. Possible hybridization mechanisms are proposed. 

[1] P. Wolfle, E. Abrahams, Ann. Phys. (Berlin) 523 598 (2011) [2] V.A. Ivanshin et al., J. Phys.: 

Conf. Ser. 324 012019 (2011) [3] T. Gruner et al., Phys. Rev. B 85 035119 (2012) 

PE09 

PE10 

PE11 


ESR study of influence of anionic and cationic substitutions in EuB6 

on the magnetic phase separation 

Tatiana Semenovna Altshuler 1 *, Yuriy Vladimirovich Goryunov 1 , Anna Vasilievna 

Levchenko 2 and Vladimir Borisovich Filippov 2 

1 Russian Academy of Sciences, Kazan Physical-Technical Institute, Russia 

2 National Academy of Sciences of Ukraine, Institute of Problem of Material Science, 

Ukraine 

We performed a comparative study of the features of the magnetic phase separation in europium 

hexaboride with anionic and cationic substitution with donor impurities. The ESR (electron spin 

resonance) were measured on the single crystal plates EuB_{6-x}C_{x} and Eu_{1-x}Gd_{x}B_{6} 

with x < 0.07 in X-band in the temperature range T = 10-300 K. Both types substitution keep integrity 

of the magnetic sublattice and they add one electron per the impurity atom in the conduction band. of 

EuB 6. The magnetic field was oriented perpendicular to the sample plane and along various crystal axis. 

In all case we observed the magnetic phase separation and phase transitions. However, the ratio of the 

magnetic phases and their behavior is slightly different for substitution boron in carbon and europium 

gadolinium. In the latter case, there was the coexistence of ferromagnetic and antiferromagnetic phases. 

The obtained ESR data are discussed in frame Falicov-Kimball model the hybridization of the localized 

electrons with two band (valence and conduction band) itinerant electrons and formation of Kondo-like 

electron states. Work was supported by Grants of RFBR and Presidium of RAS. 

[1] Altshuler T S, Goryunov Y V, Shitsevalova N Y, Dukhnenko A, JETP Lett. 88, 779 (2008) [2] 

Kunes J, Picket W E, Phys.Rev. B 69, 1651 (2004) [3] Falicov L M, Kimball J C, Phys.Rev.Lett. 22 

997 (1969) [4] Kugel K I, Rakhmanov A L, Sboychakov A O, Phys.Rev.Lett. 95, 267210 (2005) 

High pressure synthesis of novel boron-cage compounds RB 12 (R=Gd, Sm) 

Fumitoshi Iga 1 *, Yusaku Egashira 2 , Tomoaki Noguchi 2 , Toshiro Takabatake 2 , Akinori 

Kondo 3 , Koichi Kindo 3 , Shoji Yamanaka 4 , Kei Inumaru 4 , Norimasa Nishiyama 5 , 

Tetsuo Irifune 5 and Hitoshi Yusa 6 

1 Faculty of Science, Ibaraki University, Japan 

2 Graduate School of ADSM, Hiroshima University, Japan 

3 Institute for Solid State Physics, University of Tokyo, Japan 

4 Graduate School of Engineering, Hiroshima University, Japan 

5 Geodynamics Reaearch Center, Ehime University, Japan 

6 High pressure Science, National Institute Material Sciences, Japan 

Rare-earth compounds with cage structures recently attract much attention because of possibility of new heavy 

fermion mechanism using the lattice vibration [1]. Rare-earth borides such as RB 6 and RB 12 also have such cage 

structures composed by boron. However, RB 12 series are known from R = Tb to Lu. Cannon has succeeded in 

high-pressure synthesis of GdB 12 in pressure of 6.6 GPa and 2,400 C, and reported lattice parameter a = 7.523 A 

in the UB 12-type structure [2]. We have also succeeded in high-pressure synthesis of polycrystalline GdB 12 and 

SmB 12. Magnetic susceptibility of GdB 12 shows a kink at 38 K indicating of antiferro-magnetic ordering. Highfield 

magnetization of GdB 12 shows the saturation moment is 7 μB. All the reported Neel ordering temperatures 

of RB 12 well agree to the values estimated from the trivalent rare-earth dependence of de Gennes factor. From the 

x-ray powder diffraction of SmB 12, this compound also has the UB 12-type structure with lattice parameter of a = 

7.541 A. Magnetic susceptibility shows two anomalies at 9 K and 19 K different from other RB 12. 

[1] T. Hotta and K. Ueda: Phys. Rev. B 67 (2003) 104518. [2] J. F. Cannon, et al.: J. Less-Common 

Metals 56 (1977) 83. 

Magnetic anisotropy of tetragonal rare-earth compounds RRu 2Al 2B (R: 

rare-earth metals) 

Eiichi Matsuoka 1 *, Yo Tomiyama 1 , Kotaro Iwasawa 1 , Hitoshi Sugawara 1 , Takahiro 

Sakurai 2 and Hitoshi Ohta 3 

1 Department of Physics, Graduate School of Science, Kobe University, Japan 

2 Center for Supports to Research and Education Activities, Kobe University, Japan 

3 Molecular Photoscience Research Center, Kobe University, Japan 

Recently, we succeeded to synthesize polycrystalline samples of new tetragonal 

rare-earth compounds CeRu 2Al 2B and PrRu 2Al 2B and reported magnetic properties 

of these compounds [1]. Both compounds show successive phase transitions of an 

antiferromagnetic and a ferromagnetic ordering. The Neel and Curie temperatures for 

CeRu 2Al 2B are 14.3 K and 13 K, respectively, and those for PrRu 2Al 2B are 26 K and 

11 K, respectively. The values of magnetization vary when the angle between sample 

direction and applied magnetic field is changed even in the polycrystalline samples. 

This fact implies that the grains of polycrystalline samples are oriented partially and the 

variation of magnetization values is due to the magnetic anisotropy. In this study, we 

will report on the results of magnetization and magnetic-susceptibility measurements 

of grain-oriented powder samples of RRu 2Al 2B (R: rare-earth metals) and will discuss 

the magnetic anisotropy. 

[1] E. Matsuoka, Y. Tomiyama, H. Sugawara, T. Sakurai, and H. Ohta, J. Phys. Soc. Jpn. 81 (2012) 

043704. 




PE12 


Collective magnetic resonance mode in CeB 6. 

A. V. Semeno 1 *, V. V. Glushkov 1 , N. E. Sluchanko 1 , N. Yu. Shitsevalova 2 , V. B. 

Filipov 2 , A. V. Dukhnenko 2 and S. V. Demishev 1 

1 A.M.Prokhorov General Physics Institute RAS, Russia 

2 Institute for Problems of Materials Science NAS, Ukraine 

The observation of the electron spin resonance (ESR) in low temperature phase 

(phase II) of CeB 6 has risen up new questions about the nature of its ground state [1]. 

In the present work we study the effects of La doping on the ESR parameters in Ce 1xLa 

xB 6. Experiments in the doping range 0

PE18 

Charge ordering in the Kondo lattice model at quarter filling 

Junki Yoshitake*, Takahiro Misawa and Yukitoshi Motome 

Department of Applied Physics, The University of Tokyo, Japan 

The Kondo lattice model is one of the fundamental models for heavy-fermion systems, 

where exchange interactions between itinerant electrons and localized spins play an 

important role. Among many different phases described by this model, emergence of 

charge-ordered state [1,2] is interesting possibility, because this model does not include 

any bare inter-site repulsions between electrons. The possibility was first pointed out 

by a perturbation expansion in the strong Kondo coupling limit at quarter filling in 1D 

[1], and recently examined by the dynamical mean-field theory in infinite dimensions 

[2]. However, it remains unclear whether the charge-ordered state appears in two and 

three dimensions and what type of magnetic order is accommodated in the chargeordered 

state. To clarify these issues, we investigate both the ground state and finitetemperature 

properties of the quarter-filled Kondo lattice model on a square lattice by 

complementarily using the variational Monte Carlo simulation and cluster dynamical 

mean-field theory. We found that charge-ordered state appears in a wider region 

than the previous result in infinite dimensions, and that the antiferromagnetic order 

between charge poor sites is accommodated in the charge-ordered state. We discuss the 

stabilization mechanism of charge ordering by carefully analyzing the electronic and 

magnetic properties. 

[1] J. E. Hirsch, Phys. Rev. B 30, 5383 (1984). [2] J. Otsuki et al., J. Phys. Soc. Jpn. 78, 034719 

(2009). 

PE19 

Angular-dependent magnetoresistance of the filled skutterudite 

CeOs 4As 12 

Łukasz Bochenek*, Zygmunt Henkie and Tomasz Cichorek 

Division of Magnetic Research, Institute of Low Temperature and Structure Research, 

Polish Academy of Sciences, Wroclaw, Poland, Poland 

The filled skutterudite CeOs 4As 12 compound is a narrow-gap semiconductor whose 

low-temperature properties originate from a hybridization between 4f and conduction 

electrons. Nonmagnetic CeOs 4As 12 is the cubic system showing a nodal structure of 

hybridization energy gap(s) as evidenced from low-temperature (T > 0.08 K) and highmagnetic 

field (B < 14 T) studies of a directional dependence of the electrical resistivity 

ρ (T): At T < 3 K and for j || B, we found remarkable dissimilarities along the [001] and 

[111] directions, indicative of an anisotropic suppression of energy gap(s). Additionally, 

differences observed between the transverse and longitudinal magnetoresistivity cannot 

be ascribed to the Lorentz force and thus, provide a further evidence for magnetic-fieldinduced 

anisotropy of hybridization gap in CeOs 4As 12. High-quality single crystals 

of CeOs 4As 12 enable studies of a change of Fermi surface via the angular-dependent 

magnetoresistivity both in the field-induced metallic as well as semiconducting state. 

Our experiments with the use of the commercial one-axis rotator (PPMS) provide an 

additional evidence for strongly correlated electron phenomena in CeOs 4As 12 that we 

tentatively relate to the quartet Γ67 ground state of the Ce 3+ ion in the Th symmetry. 

PF01 

Spin and charge correlation of electrons at variation of interorbital 

Coulomb interaction 

Sergey Stepanovich Aplesnin 1 and Nataly Ivanovna Piskunova 2 

1 M.V. Reshetnev Siberian State Aerospace University, Russia 

2 Omsk State Agrarian University, Russia 

Of great interest for the researches is the ions with orbital degeneration and electron 

shell with filling more than half. The aim of our work is to evaluate spin and charge 

correlation at variation of interorbital Coulomb interaction and competition of electron 

hopping parameters between nearest sites on the same and different orbitales arising 

as a result of variation of orbitales filling. Variation of charge gap may be also cause a 

radical change in the electronic density and spin correlation functions. We calculated 

electron spectrum in the Hubbard model with electron filling n=1.5 and following 

parameters: energy level of ions, the matrix element of the hopping between the 

nearest sites and orbitales, U and V is the Coulomb repulsion of the electrons on site 

and between orbitales . We calculated the eigenvalue spectrum and the corresponding 

state vectors by exact diagonalization for small cluster, based on which we determined 

the spin correlation functions on the longitudinal and transverse spin components, 

correlator of electron density. As a results, critical parameters Vc of the interorbitales 

Coulomb interaction and hopping integral are found at which reveal change in the 

value and sign of exchange interaction and in the correlator of electron density. 

PF02 

PF03 

PF04 


Superfluid state of repulsively interacting three-component fermionic 

atoms in optical lattices 

Seiichiro Suga 1 * and Kensuke Inaba 2 

1 University of Hyogo, Japan 

2 NTT Basic Research Laboratories and JST CREST, Japan 

We investigate the superfluid state of repulsively interacting three-component 

(color) fermionic atoms in optical lattices. We first discuss the effective interactions 

using diagrammatic approaches. We then investigate the superfluid properties using 

complementary two methods: the dynamical mean-field theory with a perturbative 

approach and the self-energy functional approach. We show that when the anisotropy 

of the three repulsive interactions is strong, atoms of two of the three colors form 

Cooper pairs and atoms of the third color remain a Fermi liquid. An effective attractive 

interaction is induced by density fluctuations of the third-color atoms. This superfluid 

state is similar to the color superfluid of the attractively interacting three-component 

systems. We show from dynamical properties that the Cooper-pairing mechanism 

is basically similar to that of the conventional phonon-mediated superconductivity. 

The superfluid state is stable against changes in filling close to half filling. We 

determine the phase diagrams in terms of temperature, filling, and the anisotropy of the 

repulsive interactions. We also discuss the relation between the theoretical results and 

experiments. 

Magnetism in complex oxides: A challenge for advanced ab-initio 

methods. 

Alessio Filippetti 

Dept. of Physics, CNR-IOM, University of Cagliari, Italy, Italy 

The accurate description of magnetic properties in complex oxides by first-principles is 

tantamount with the possibility of achieving reliable theoretical design of oxide-based 

spintronic devices. Alas, standard first-principles approaches fails to properly describe 

strong correlated systems, and more sophisticated approximations are required. 

Recently the novel variational pseudo-self-interaction corrected density functional 

theory (VPSIC) has been introduced, showing great potential as theoretical tool for 

the study of complex oxides and strong-correlated systems in general, and promising 

to open the field to reliable designs of magnetic oxide-based devices. Here we apply 

the new approach to investigate two prototypical oxide families, i.e. transition metal 

monoxides (MnO, NiO) and perovskite titanates (LaTiO 3, YTiO 3). We give evidence 

that the new theory is capable to furnish an unprecedentedly accurate description of 

both ground-state and finite-temperature magnetic properties, both at equilibrium 

and under pressure. As highlights of the results obtained in the work, we mention the 

correct determination of critical temperature and the accurate description of orbital 

ordering in transition metal oxides. 

Resonating Hartree-Fock Studies for spin fluctuations in the Hubbard 

model on triangular lattice 

Norikazu Tomita* 

Yamagata University, Japan 

Electron correlation effects in geometrically frustrated systems have attracted much 

attention in condensed-matter physics. In fact, these systems show a variety of 

interesting and non-trivial ground states. On the other hand, theoretical description on 

the electron correlations in these systems is difficult, and origins of such non-trivial 

states are not yet clarified. In this research, the electron correlations are visualized 

from the viewpoint of quantum fluctuations. Such visualization is important for the 

fundamental understanding and applications of the frustrated system. A resonating 

Hartree-Fock method constructs a many-body wave-function by superposition of 

non-orthogonal Slater determinants, where superposition coefficients and orbitals in 

all the Slater determinants are simultaneously optimized. We can visualize quantum 

fluctuations from the structures of Slater determinants generating the wave-function. 

We have previously demonstrated that quantum fluctuations in the doped Hubbard 

model on a square lattice are described by vibrations and translations of polarons. 

[Phys. Rev. Lett. 103(2009)116401.] Now, the half-filled Hubbard model on a uniform 

triangular lattice are considered. The ground state is metallic and non-magnetic when 

U is weak. We show that non-magnetic ground state is realized by the large quantum 

fluctuations due to hybridization of two different co-linear spin-density waves and their 

modulations. [Phys. Rev. B84(2011)245101.] 




PF05 


Theory of momentum-dependent variational ansatz to strongly 

correlated electron system 

M. Atiqur R. Patoary* and Yoshiro Kakehashi 

Univ. of the Ryukyus, Nishihara, Okinawa, Japan 

We have recently developed Momentum dependent Local-Ansatz wavefunction (MLA) 

approach to describe the correlated electron system in the weak and intermediate 

Coulomb interaction (U) regime. The theory did not work best in the strong U 

regime because we started from the Hartree-Fock (HF) wavefunction. To overcome 

the difficulty, we propose here a new hybrid wavefunction in which the starting 

wavefunction can vary via a new variational parameter w from the HF wavefunction 

(w=0) suitable for the weak interaction regime to the alloy-analogy (AA) wavefunction 

(w=1) suitable in the strong interaction regime. The extended method overcomes 

the standard variational method such as the Gutzwiller wavefunction approach (GA) 

irrespective of U. We have demonstrate that the energy for the MLA-AA (w=1) is 

lower than those of the MLA-HF (w=0) in the strong U region for the half-filled band 

Hubbard model for the hypercubic lattice in infinite dimensions. Moreover, the energy 

of the MLA (w=0 and 1) is always lower than the GA. We have also verified that the 

double occupation number, quasi-particle weight and momentum distribution function 

are much improved by the new MLA. 

PF06 

Metal-insulator transition in orthorhombic Perovksite PbRuO 3 

Young-joon Song 1 and Kwan-woo Lee 2 * 

1 Department of Applied Physics, Graduate School, Korea University, Sejong, Korea 

2 Department of Display and Semiconductor Physics, Korea University, Sejong, Korea 

Transition metal oxide perovskites show abundant physical phenomena such as 

superconductivity, CMR, ferroelectricity, and unusual magnetic behavior. Recently, the 

orthorhombic perovskite PbRuO 3, which was first synthesized 40 years ago, has been 

revisited by two experimental groups. Commonly, the measurements of temperaturedependent 

magnetic susceptibility show a kink at 90 K, where a structural transition 

occurs, but no magnetic ordering has been observed even at very low T. Remarkably, 

the resistivity measurements of Kimber et al. indicate a metal-insulator transition, but 

ones of Cheng et al. shows a metal-metal transition though a kink appears at 90 K. 

To understand this discrepancy, we have carried out first principles calculations using 

various approaches: correlated band theory (LDA+U), LDA+U+SOC (spin-orbital 

coupling), modified BJ, and fixed spin moment calculations. In this presentation, we 

will address the electronic and magnetic structures on PbRuO 3 in more detail and a 

scenario on the discrepancy. 

PF07 

Ferromagnetic semiconductor-metal transition in heterostructures of 

europium monoxide 

Tobias Stollenwerk* and Johann Kroha 

Physikalisches Institut, University of Bonn, Germany 

WITHDRAWN 


PF08 

The temperature dependence of the staggered magnetisation in 

itinerant weak antiferromagnets 

Nobukuni Hatayama 1 , Rikio Konno 1 * and Yoshinori Takahashi 2 

1 Kinki University Technical College, Japan 

2 Graduate School of Material Science, University of Hyogo, Japan 

Effect of spin fluctuations on the staggered magnetisation in itinerant weak 

antiferromagnets is investigated below the Neel temperature T N. It is known that the 

discontinuous change of the magnetisation occurs at the critical temperature in the 

rotationally invariant treatment in the self-consistent renormalization spin fluctuation 

theory. The difficulty is resolved in itinerant weak ferromagnets by Takahashi [J. Phys.: 

Condens. Matter 13 (2001) 6323. ]. In this paper, we extend his theory to the case of 

weak antiferromagnets. We have succeeded in deriving the temperature dependence 

of the staggered magnetisation below T N, by taking account the effects of spin-waves 

excitations into the transverse component of the dynamical magnetic susceptibility 

within the small area of wave-vector space around the staggered wave-vector. We 

found T 3/2 -linear behaviour of the staggered magnetisation at low temperatures 

compared with T N. 

PF09 

Theory of excitonic insulator in the two orbital Hubbard model: 

Variational cluster approach 

Tatsuya Kaneko 1 *, Kazuhiro Seki 1 , Satoshi Nishimoto 2 and Yukinori Ohta 1 

1 Department of Physics, Chiba university, Japan 

2 Institut fur Theoretische Festkorperphysik, IFW Dresden, Germany 

Motivated by the recent experimental and theoretical studies of excitonic insulators, we 

investigate the spontaneous symmetry breaking of the excitonic insulator state in the 

two-orbital Hubbard model defined on the two-dimensional square lattice. Using the 

variational cluster approximation (VCA) and Hartree-Fock approximation (HFA), we 

evaluate the number of particles on each orbital, staggered magnetization in the Mott 

insulator phase, the order parameter indicating the coherence between electrons and 

holes in the excitonic insulator phase, and the ground-state phase diagram as functions 

of intra-orbital and inter-orbital Coulomb interactions. We also calculate the singleparticle 

excitation spectra of the band insulator, Mott insulator, and excitonic insulator 

phases. We thereby argue that the normal metallic phase is unstable to the formation of 

the excitonic insulator phase, which should appear in a wide parameter region between 

the band insulator and Mott insulator phases. 

PF10 

Layered chalcogenide Ta 2NiSe 5 as a candidate for excitonic insulators - 

theoretical aspects 

Tatsuya Kaneko 1 *, Tatsuya Toriyama 1 , Takehisa Konishi 2 and Yukinori Ohta 1 


2 Graduate School of Advanced Integration Science, Chiba university, Japan 

The electronic structure of layered chalcogenide Ta 2NiSe 5, a candidate for excitonic 

Insulators, is calculated using the generalized gradient approximation in the density 

functional theory, where the Hubbard-type repulsive interaction is taken into account. 

We find for the low-temperature monoclinic phase that the conduction band has a 

cosinelike quasi-one-dimensional (1D) band dispersion coming mainly from the 5dxy 

orbitals of Ta ions arranged along the a-direction of the lattice, whereas the top of 

the valence band has a quasi-1D dispersion coming mainly from the Ni 3dxz+3dyz 

and Se 4px+4py orbitals arranged alternately along the a-direction. The electronic 

state near the Fermi level is thus described by the quasi-1D structural unit consisting 

of these orbitals. The electronic structure of Ta 2NiS 5, which has the orthorhombic 

crystal structure, is also calculated to clarify the role of the lattice distortion. Three 

scenarios are suggested to explain the characteristic temperature dependence of the 

band structure observed in the angle-resolved photoemission: a scenario of the band 

deformation due to the monoclinic lattice distortion, a scenario of the formation of the 

excitonic insulator state, and a scenario made from the combination of the former two 

where the monoclinic lattice distortion and formation of the excitonic insulator state 

occur cooperatively.

PF11 

Electric dipolar susceptibility of the Anderson-Holstein model 

Takahiro Fuse* and Takashi Hotta 

Department of Physics, Tokyo Metropolitan University, Japan 

Recently, cage structure materials have attracted much attention due to intriguing 

magnetic phenomena induced by the coupling effect between electrons and rattling, i.e., 

anharmonic local oscillation of guest ion in a cage. When the guest ion oscillates in the 

cage, there should occur electric dipole moment P, given by P=Zex, where Z denotes 

the valence of the guest ion, e indicates electron charge, and x is ion displacement. In 

order to investigate properties of electron-rattling system, we evaluate electric dipolar 

susceptibility χp on the basis of the Anderson-Holstein model, which consists of 

conduction electron term, hybridization between conduction and localized electrons, 

Coulomb interaction between localized electrons, and coupling between ion oscillation 

and local charge density. We analyze the model by using the numerical renormalization 

group (NRG) method. Note that χp is directly related to the phonon Green’s function D. 

For the evaluation of D, we pay due attention to the phonon excited states kept in the 

renormalization process. We carefully evaluate D with the use of NRG and compare 

it with that obtained from charge susceptibility in the combination with the Dyson 

equation. Then, we discuss the effects of anharmonicity and Coulomb interaction on 

χp. 

PF12 

Insulator version of the double-exchange ferromagnetism 

Yukinori Ohta 1 *, Satoshi Nishimoto 2 and Kyohei Nakano 1 

1 Department of Physics, Chiba University, Japan 

2 Institute for Theoretical Solid State Physics, IFW-Dresden, Germany 

The double-exchange ferromagnetism is known to appear when the coherent motion 

of electrons occurs in the conduction band that is coupled with the localized spins via 

the ferromagnetic Heisenberg-type exchange interaction, i.e., the Hund's rule coupling. 

A natural and realistic issue that arises is then what happens with the ferromagnetism 

when a gap opens in the conduction band and coherent motion of electrons ceases. 

To answer this question quantitatively, we apply the density-matrix renormalization 

group method to the study of the one-dimensional double-exchange model, where 

we introduce the Peierls-type lattice distortion in the conduction band to make the 

system an insulator with the band gap. We find from the analysis that the doubleexchange 

ferromagnetism persists strongly unless the strength of the lattice distortion 

exceeds a certain critical limit; we thus call this an insulator version of the doubleexchange 

ferromagnetism. We note that this type of ferromagnetism actually occurs in 

a chromium hollandite K 2Cr 8O 16, where a half-metallic ferromagnet due to the doubleexchange 

mechanism undergoes a metal-insulator transition, resulting in the realization 

of a ferromagnetic insulator [1]. 

[1] Toriyama et al., Phys. Rev. Lett. 107, 266402 (2011). 

PF13 

Metallic ferromagnetism in the 3D Hubbard model at finite 

temperature 

Andre Neves Ribeiro and Claudio Andrade Macedo* 

Departamento de Fisica, Universidade Federal de Sergipe, Brazil 

The dynamical mean-field approximation (DMFA), when used to study strongly 

correlated electron systems (SCES), allows the obtainment of thermodynamic 

properties in a nonperturbative regime. The Hubbard model is the simplest model 

capable of describing the essential physics of SCES. Thus, we investigated 

the existence of ferromagnetism in the Hubbard model on fcc lattices, at finite 

temperatures, using the DMFA with effective parameters solved by exact numerical 

diagonalization. We calculated the magnetization for 0.3 n 0.9 (where n is the number 

of electrons per site), with temperature of 0.04t/kB (where t is the hopping integral 

between nearest-neighbor sites) and the value of the on-site Coulombian interaction U 

equal to 3W (where W denotes the noninteracting energy bandwidth). Our results reveal 

a significant magnetization for n = 0.6, 0.7 and 0.8. The densities of states indicate that 

these systems are metallic. In the particular case for n = 0.6, magnetization, internal 

energy and specific-heat curves versus temperature were calculated to that value of U. 

This work provides an affirmative answer to the question whether the Hubbard model 

with only nearest-neighbor hopping, on a three-dimensional lattice, and finite both 

temperature and on-site Coulombian interaction, exhibits ferromagnetism when solved 

using the DMFA. 

PF14 

PF15 

PF16 


BCS-BEC crossover in the extended Falicov-Kimball model: 

Variational cluster approach 

Kazuhiro Seki 1 *, Robert Eder 2 and Yukinori Ohta 1 


2 Institut fuer Festkoerperphysik, Karlsruhe Institute of Technology, Germany 

We study the spontaneous symmetry breaking of the excitonic insulator state induced 

by the Coulomb interaction U in the two-dimensional extended Falicov-Kimball model. 

Using the variational cluster approximation (VCA) and Hartree-Fock approximation 

(HFA), we evaluate the order parameter, single-particle excitation gap, momentum 

distribution functions, coherence length of excitons, and single-particle and anomalous 

excitation spectra as functions of U at zero temperature. We find that in the weak-tointermediate 

coupling regime, the Fermi surface plays an essential role and calculated 

results can be understood in close correspondence with the BCS theory, whereas in the 

strong-coupling regime, the Fermi surface plays no role and results are consistent with 

the picture of a Bose-Einstein condensate (BEC). Moreover, we find that HFA works 

well in both the weak and strong-coupling regimes, and that the difference between 

the results of VCA and HFA mostly appears in the intermediate-coupling regime. The 

reason for this is discussed from a viewpoint of the self-energy. Details are reported in 

Ref. [1]. 

[1] K. Seki, R. Eder, and Y. Ohta, Phys. Rev. B 84, 245106 (2011). 

Theory of the metal-insulator transition and charge/orbital states in 

V 6O 13 

Takayoshi Nakayama 1 *, Tatsuya Toriyama 1 , Takehisa Konishi 2 and Yukinori Ohta 1 


2 Graduate School of Advanced Integration Science, Chiba University, Japan 

The Wadsley-phase vanadium oxide V 6O 13 has the crystal structure composed of the 

two-dimensional single and double trellis lattices, where the V ions are in the mixed 

valent state with an average valence of V4.33+ (3d0.66); i.e., there are formally 

V5+ (3d0) and V4+ (3d1) in a 1 : 2 ratio. This material undergoes a metal-insulator 

transition (MIT) at 150K, which is accompanied by the structural distortion, and 

shows an antiferromagnetic order below 55K. To clarify the electronic structure of this 

material, we make the density-functional-theory-based electronic structure calculations 

and discuss the mechanism of the MIT, as well as its charge and orbital states above 

and below the MIT. We find that the band structure obtained is in reasonable agreement 

with the observed angle-resolved photoemission spectra but that the characteristic 

distribution of valence electrons is not necessarily compatible with the results of a 

recent NMR experiment. We also find that, if we assume the observed low-temperature 

crystal structure in the calculations, we obtain the insulating solution with an 

antiferromagnetic order, which is in agreement with experiment. 

Statistical dynamical mean field study of correlated fermions with 

disorder 

Masaru Sakaida*, Kazuto Noda and Norio Kawakami 

Kyoto university, Japan 

Disordered systems with strong correlation effects have been studied in solid state 

physics, and even now have attracted much interest. Various experiments have been 

performed extensively, and in particular a disordered system of strongly interacting 

cold atoms has been experimentally realized recently[1]. Statistical dynamical meanfield 

theory[2,3] to treat disorders and strong correlation effects on equal footing and 

non-perturbatively makes it possible to capture essential features of the Anderson 

transition beyond the coherent-potential approximation. In this work, we analyze the 

tight-binding fermion model on the Bethe lattice in which the box disorder manifests 

itself by random on-site energies. We systematically investigate characteristic behaviors 

of the density of states and the conductivity to estimate competitions between disorders 

and correlation effects in this system. 

[1] L. Fallani et al., Phys. Rev. Lett. 98, 130404 (2007) [2] V. Dobrosavljevic et al., Phys. Rev. Lett. 

78, 3943 (1997) [3] D. Semmler et al., Phys. Rev. B 84, 115113 (2011) 




PF17 


Analysis of many-body effects on anisotropic magnetic properties of 

YbB 12 

Yoshihiro Kikuchi*, Yoshiki Imai and Tetsuro Saso 

Department of Physics, Saitama University, Japan 

YbB 12 is one of the typical Kondo insulator and many experiments are already reported. 

Although it has cubic structure, critical magnetic fields of insulator-to-metal transition 

are anisotropic[1]. Moreover anisotropic magnetization is observed above the critical 

field[2]. One of the authors studied the magnetic properties by means of tight binding 

model, composed of Yb 5dε and 4f Γ 8 orbitals[3]. The results were qualitatively in 

agreement with the experiments but a quantitative disagreement was left, because 

many-body effects were not taken into account. Therefore, we introduce coulomb 

repulsion between f-electrons in the tight binding model. We apply the dynamical mean 

field theory, in which we solve the effective impurity problem by using the continuoustime 

quantum Monte Carlo method. We compare obtained result with the experimental 

one’s quantitatively, and discuss the many-body effects in the magnetic properties of 

YbB 12. 

[1] F. Iga et al. : Jpn. J.Appl. Phys. Series 11(1999)88 [2] S. Hiura, et al.: Physica B 

281&282(2000)271 [3] T. Izumi, Y. Imai, T. Saso : J. Phys. Soc. Jpn. 76(2007)084715 

PF18 

The ground state energies of spinless free fermions and hard-core 

bosons in 2D square lattices 

Wenxing Nie 1 and Masaki Oshikawa 2 * 


2 The institute for Solid State Physics, The University of Tokyo, Japan 

We compare the ground state energies of hard-core bosons and spinless free fermions 

on the same lattice. Ground state energy of bosons is usually expected to be lower 

than that of fermions, because bosons can condense into the lowest energy state. 

However, in the presence of hard-core interaction among bosons, the condensation is 

not perfect and comparison is nontrivial. We find that, in the absence of frustration, the 

ground state energy of hard-core bosons is indeed lower than that of free fermions. In 

general, however, the hard-core bosons could have higher ground state energy than the 

fermions on the same lattice if there is a frustration. In fact, there is an exactly solvable 

one-dimensional model, in which the ground state energy of bosons is proved to be 

higher. However, the difference vanishes in the thermodynamic limit. We also studied 

the two-dimensional square lattice with uniform magnetic flux perpendicular to the 

lattice, by numerical diagonalization. As the magnetic flux introduces frustration, we 

actually find the ground state energy of hard-core bosons is higher for a range of flux 

and particle density. In the two dimensional case, this difference seems to persist in the 

thermodynamic limit, in contrast to the one-dimensional case. 

[1]Phys. Rev. B 14, 2239 (1976) [2]Phys. Rev. Lett. 83, 2246(1999) [3]Phys. Rev. Lett. 96, 036406 

(2006) 

PF19 

Correlation effect in ferromagnetic 3d transition metals 

Muneyuki Nishishita 1 , Sudhakar Pandey 2 and Dai Hirashima 1 * 

1 Nagoya University, Japan 

2 APTPC, Korea 

Selfconsistent perturbation theory is applied to ferromagnetic 3d transition metals, Fe 

and Ni. Realistic tight-binding model is used to describe the electronic states of the 

system. It is found that a reasonable value of the Curie temperature for Fe is obtained 

for realistic strength of the Coulomb interaction. Dynamical transverse susceptibility 

is also calculated. Here, vertex corrections are considered so that the spin rotational 

symmetry is preserved. Then, the spin-wave energy correctly vanishes in the longwavelength 

limit. The effect of the electron correlation on the spin stiffness is clarified. 

We also compare the spin fluctuation spectra below and above the Curie temperature 

and discuss the possible short-range order above the Curie temperature. 


PG01 

Ferrimagnetic compensation in a Fe64Er19B17 glass, - the head of a 

dandelion, or the spokes of a wheel? 

Andrew R. Wildes 1 *, Neil Cowlam 2 and Nourh A. Al-senany 3 

1 

Institut Laue-Langevin, BP 156, 6 rue jules Horowitz, 38042 GRENOBLE Cedex 9, 

France 

2 

Department of Physics and Astronomy, University of Sheffield, SHEFFIELD, S3 

7RH, United Kingdom 

3 

Department of Physics and Astronomy, University of Sheffield, SHEFFIELD, S3 

7RH, King Abdulaziz University, Jeddah, Saudi Arabia, United Kingdom 

Magnetization and neutron scattering measurements with polarization analysis were 

made on a Fe 64Er 19B 17 glass to investigate its ferrimagnetic compensation at T(comp) 

= 112 ± 2K. The measurements prove that the glass has a non-collinear magnetic 

structure. The two non-spin flip cross-sections interchange between 100K and 125K, 

proving the magnetic structure flips at T(comp). They are identical at 112K where 

the forward limit of the spin flip cross-sections was greatest. The mean collinear 

components of the moments therefore go to zero at T(comp). If the moment vectors 

were mapped to originate at a point, the data correspond either to the moments being 

randomly oriented like the head of a dandelion, or with a collapse of the moments into 

a plane normal to the field, like the spokes of a wheel. The data will be presented and 

the possible driving mechanisms for the ferrimagnetic compensation will be discussed. 

PG02 

Evolution of reverse magnetized seed in monodomain uniaxial garnet 

film elements 

Vladimir Skidanov* 

Nanoelectronics and Spintronics Department, Institute for Design Problems in 

Microelectronics RAS, Russia 

Evolution of cylindrical domain seeded in monodomain film and film circular element 

was investigated numerically and experimentally. It is found that in continuous film in 

zero external magnetic field cylindrical domain may expand unlimitedly or collapse 

independently on initial diameter of the seed. Single seed expansion followed by 

film magnetization reversal is observed if l/h < 1.38 (where l is garnet characteristic 

length, h is film thickness). Constant positive external magnetic field antiparallel 

to magnetization inside seed supports stable domain diameter which is inverse 

proportional to field intensity H. Cylindrical domain inside disk is found stable in 

zero and negative external magnetic field due radial gradient of inhomogeneous stray 

field of the disk boundary. If l/h > 1.38 reverse magnetized seed collapses in zero 

external field. Stable domain doesn’t exist in constant negative external field parallel 

to seed magnetization this case. Unlimited domain expansion takes place if modulus 

of negative H exceeds critical value which is inverse proportional to initial seed 

diameter. Domain is stable if domain wall embraces circular hole in garnet film. This 

case garnet boundary stray field prevents from domain contraction in zero and positive 

external field. Two-domain ring-shape elements can be utilized as fast magnetooptical 

modulators. 

PG03 

Re-entrant structure and critical behaviour of Fe-Cr and Fe-V sigmaphase 

alloys 

Reginaldo Barco 1 , Paulo Pureur 1 , G L F Fraga 1 and Stanislaw M Dubiel 2 

1 Physics, UFRGS Porto Alegre, Brazil 

2 Physics and Applied Computer Science, AGH University Krakow, Poland 

The σ-phase (tetragonal unit cell, space group D144h-P42/mnm) belongs to a family 

of a complex Frank-Kasper phases. It can be formed in transition-metal alloys. Only 

two alloys, among about 50 examples of σ known to occur in binary systems, viz. Fe- 

Cr and Fe-V have well-evidenced magnetic properties. The magnetic ordering of σ 

has been regarded as ferromagnetic (FM) with the Curie temperatures, Tc, below ~40 

K for σ-FeCr and below ~315 K for σ-FeV. Here we report a clear evidence that the 

ground state of the σ-phase Fe 0.53Cr 0.47 and Fe 0.52V 0.48 alloys is a re-entrant spin-glass 

(RSG). The evidence was found from a study of magnetization versus temperature, T, 

and magnetic field, H. Based on the field-cooled and zero-field-cooled magnetization 

curves recorded in different fields, H, phase diagrams in the H-T plane could have been 

drawn. They display the location of the paramagnetic (P), FM and RSG states, and are 

in a qualitative accord with predictions of the mean-field theory. Critical behaviour near 

Tc was also studied with both conventional and extended protocols, and the critical 

exponents β, γ, δ were determined.

PG04 

Pressure effects in the ferromagnetic shape memory alloys Ni 2Mn 1xCu 

xGa 

Tomoya Miura 1 , Yoshiya Adachi 1 *, Keita Endo 2 , Ryosuke Kainuma 2 and Takeshi 

Kanomata 3 

1 Graduate School of Science and Engineering, Yamagata University, Japan 

2 Department of Materials Science, Tohoku University, Japan 

3 Faculty of Engineering, Tohoku Gakuin University, Japan 

The Heusler alloy Ni 2MnGa attracts attention as an actuator material because the 

magnetic distortion of about 10% is observed just below the martensitic transition 

temperature (TM). The pressure dependence coefficient of the Curie temperature of 

Ni 2MnGa is +1.0×10-8 K/Pa.[1] In the Ni 2Mn 1-xCu xGa alloy system, TC and TM were 

reported by Kataoka et al.[2] that the samples with the range of x < 0.23, 0.23 < x < 

0.30 and x > 0.30 are characterized TC > TM, TC = TM and TC < TM, respectively. 

We carried out the initial permeability measurements under pressure up to 1 GPa for 

Heusler Ni 2Mn 1-xCu xGa system. TM and TC were determined from the change of 

the initial permeability under each pressure. It was found that TM was considered to 

coincide with TC in 0.23 < x < 0.30. Moreover it was obtained dTC/dp is positive 

in x < 0.23 and dTC/dp is negative in x > 0.30. As a result, the temperature-pressure 

magnetic phase diagram was obtained. We’d like to discuss the mechanism of the 

martensitic transformation in Heusler alloy Ni 2Mn 1-xCu xGa system. 

[1] T.Kanomata et al.: J. Magn. Magn. Mater 65 (1987) 76. [2] M. Kataoka et al.: Phys. Rev B 82 

(2010) 214423. 

PG05 

Electronic state of Cr and collapse-like decrease of Fe magnetic 

moment in amorphous (Fe-Cr)B alloys 

Kazuo Yano 1 *, Tastuo Kamimori 2 , Hiroaki Kanetsuki 2 , Hatsuo Tange 2 , Masayoshi 

Itou 3 , Yoshiharu Sakurai 3 , Eiji Kita 4 and Hiromitsu Ino 5 

1 

College of Science and Technology, Nihon University, Japan 

2 

Faculty of Science, Ehime University, Japan 

3 

JASRI/SPring8, Japan 

4 

Applied Physics, University of Tsukuba, Japan 

5 

Faculty of Engineering, University of Tokyo, Japan 

Magnetic properties in amorphous alloys have been extensively investigated in rare earth (RE)-transition 

metal (TM) systems and transition metal (TM)-mettaloids systems. Many interesting and important 

problems have been investigated and solved, however, some of the important problems seem to be hard 

nuts to crack and remain unsolved. One of the unsolved and interesting problems is an anomaly in Slater- 

Pauling curve discovered by Mizoguchi et al. and the Fe magnetic moment decreases abruptly, for example 

in (Fe-Cr) 80B 20 amorphous alloys. For instance, the substitution of Fe by only 10 at% of Cr causes about 

50 %decrease of Fe magnetic moment. Mizoguchi et al. suggested that the Cr retained magnetic moment 

and coupled anti-parallel to that of Fe, however there have been no decisive experimental results. In order 

to detect and examine the Cr magnetic moment, one of the powerful tools for this aim, is the magnetic 

Compton scattering profile (MCP) method which can obtain the infornmations of 3d electrons and the 

spin-polarized outer 4s, 4p electrons, separately. The MCP measurement was carried out for (Fe-Cr) 80B 20 

(Cr=0.1, 0.2, 0.3) and the result suggest the existence of Cr magnetic moment coupling antiparallel to that 

of Fe. Macroscopic magnetic properties were also measured and analyzed. 

PG06 

Micromagnetic simulation of CNT-MFM probes under magnetic field 

Takashi Manago 1 *, Hironori Asada 2 and Hiromi Kuramochi 3 

1 Department of Applied Physics, Fukuoka university, Japan 

2 Graduate School of Science and Engineering, Yamaguchi university, Japan 

3 <strong>International</strong> Center for Materials Nanoarchitectonics, National Institute for 

Materials Science(NIMC), Japan 

Ferromagnetic-film-coated carbon nanotube in a magnetic force microscope (CNT- 

MFM) demonstrated the high spacial resolution of about 10 nm and low perturbation. 

The magnetic strucutres of CNT-MFM probes were investigated using threedimensional 

micromagnetic simulation and it showed the advantages of the CNT-MFM 

probes [1]. In this paper, the stability of the magnetic structure in external magnetic field 

was investigated to confirm magnetic robustness using micromagnetic simulation. At a 

remanent state, the magnetic moments of the CNT-MFM probe align almost along the 

longitudinal direction of the CNT lod due to the shape anisotropy. When the opposite 

magnetic field applied, the magnetic moments of the probes reversed all at once at 

about 200 mT. In the pyramidal probe, the vortex core was appeared around the tip at 

a remanent state. When the opposite magnetic field applied, the magnetization of the 

side wall gradually tilted, and at last the vortex core was reversed. Thus magnetization 

reversal process is quite different because of large difference in magnetic structures 

between the CNT-MFM and pyramidal probes. We found that the CNT-MFM probes 

have better magnetic robustness than the conventional pyramidal probes. 

[1] T. Manago et al., Nanotechnology, 23, 035501 (2012). 

PG07 

PG08 

PG09 


Pressure effect of metamagnetic shape memory alloy Pd 2Mn 1+xSn 1-x 

Yohei Yamazaki 1 , Takamitsu Akama 2 , Hironari Okada 1 *, Takeshi Kanomata 1 and 

Ryosuke Kainuma 3 

1 Division of Engineering Graduate School, Tohoku Gakuin University, Japan 


3 Graduate School of Engineering, Tohoku University, Japan 

Recently, it has been reported that NiMnX (X = In, Sn and Sb) Heusler alloys show 

metamagnetic shape memory effect. In these alloys, the martensitic transformation 

temperature decreases with increasing magnetic field, and magnetic field-induced 

reverse martensitic transformation associated with metamagnetic transition occurs 

below the martensitic transformation temperature. Since the magnetic fieldinduced 

transformation leads an almost perfect shape memory effect, these alloys 

attract attention as new type of ferromagnetic shape memory alloys. Very recently, 

similarly to NiMnX Heusler alloys, it has been found that PdMnSn Heusler alloys 

show metamagnetic shape memory effects and a drastic change with martensitic 

transformation in magnetic and transport properties. In this study, in order to investigate 

pressure effect on martensitic transformation in PdMnSn Heusler alloys, we performed 

electrical resistivity measurements under high pressure. As a result, it was found that 

the pressure-temperature phase diagram is similar to the temperature-Mn content phase 

diagram. These results suggest that the atomic distance plays an important role for 

martensitic transformation in PdMnSn Heusler alloys. 

Engineering of Co atomic 1-D chains on Ag(111) with tailored magnetic 

ground state. 

David Serrate 1 *, Maria Moro 1 , Marten Piantek 2 , Jose Ignacio Pascual 3 and Manuel 

Ricardo Ibarra 1 

1 Instituto de Nanociencia de Aragon, University of Zaragoza, Spain 

2 Instituto de Ciencia de Materiales de Aragon, CSIC-University of Zaragoza, Spain 

3 Institut fur Experimentalphysik, Freie Universitat Berlin, Germany 

Certain magnetic adatoms lying on a metal surface give rise to a Kondo resonance. We used the 

model system of Co atoms on Ag(111) to investigate their magnetic interactions through the Kondo 

resonance [1,2] . The Co atoms architecture and the substrate LDOS landscape are artificially 

arranged by means of lateral manipulation with a scanning tunneling microscope (STM) tip at 4.8 

K. The resonance is subsequently characterized by means of STM spectroscopy. Individual Co 

atoms in natural equilibrium positions at minima of the surface LDOS exhibit Kondo temperature 

TK=90 K in agreement with earlier studies [3]. TK can be gradually varied from 60 to 145 K by 

positioning the same atom in different Ag LDOS values of the interference patterns. The coordination 

with neighboring Co atoms increases TK when their distance decreases below four Ag(111) lattice 

parameters (2.9 A). In Co chains with N atoms (N=2,3,...,19), both the amplitude and the spatial extent 

of the many-body wave function of the Kondo resonance are reduced with increasing coordination. In 

the frame of the two impurity Kondo theory, our data unveil the nature of direct Co-Co and substrate 

mediated magnetic interactions as a function of the local electronic and structural environment. 

[1] A. Otte et al., Nature Phys. 4, 847 (2008) [2] J. Bork et al., Nature Phys. 7, 901 (2011) [3] M.A. 

Schneider et al., Phys. Rev. B 65, 121406R (2002) 

Pressure-induced suppression of magnetic ordering in a chiral magnet 

Cr1/3NbS2 Takumi Imakyurei 1 , Kousuke Nagai 1 , Masaki Mito 1 , Hiroyuki Deguchi 1 , Jun-ichiro 

Kishine 1 , Takayuki Tajiri 2 , Katsuya Inoue 3 , Yuya Nakao 4 , Yusuke Kousaka 4 and Jun 

Akimitsu 4 

1 

Faculty of Engineering, Kyushu Institute of Technology, Japan 

2 

Faculty of Science, Fukuoka University, Japan 

3 

Department of Chemistry and Institute for Advanced Materials Research, Hiroshima 

University, Japan 

4 

Department of Physics and Mathematics, Aoyama-Gakuin University, Japan 

Cr 1/3NbS 2 is a chiral magnet without structural inversion center. The magnetic property 

is attributed to the localized moment of Cr, and metallic conductivity is attributed 

to conduction electrons of Nb. We expect that Cr 1/3NbS 2 would become a noncentrosymmetric 

superconductor after disappearance of magnetic ordering at high 

pressure. Thus we carried out the AC susceptibility measurements at pressures up to 10 

GPa and powder X-ray diffraction experiments at room temperature up to 7 GPa for 

the powder sample of Cr 1/3NbS 2. In the pressure region of below 3 GPa, the anomaly 

of magnetic susceptibility due to the magnetic ordering shifted toward low temperature 

side and the magnitude was gradually suppressed. At present, the Meissner signal has 

not yet been observed in the temperature region down to 2 K and the pressure region 

up to 10 GPa. The lattice parameters exhibited the change of contraction at around 3 

GPa, where it became difficult to evaluate the magnetic ordering temperature. 




PG10 


Multiple ESR spectra in a chiral molecule-based magnet [Cr(CN) 6] 

[Mn(R )-pnH(H 2O)](H 2O) 

Takuma Nagano 1 , Masaki Mito 1 , Seishi Takagi 1 , Hiroyuki Deguchi 1 , Jun-ichiro 

Kishine 1 , Yusuke Yoshida 2 and Katsuya Inoue 2 


2 Department of Chemistry and Institute for Advanced Materials Research, Hiroshima 


A molecule-based magnet [Cr(CN) 6][Mn(R)-pnH(H 2O)](H 2O) (abbreviated as R-GN) is a chiral 

magnet without inversion center and mirror reflection. The magnetic network is constructed with 

the help of a chiral ligand diaminopropane. In R-GN, multiple spectra of ESR were observed 

below magnetic order temperature by Morgunov et al. [1]. They concluded that the phenomenon 

was caused by the formation of a chiral soliton lattice, which originated from incommensurate 

magnetic structure. However, we have a suspicion against their interpretation, because R-GN 

indeed exhibits no incommensurate magnetic structure. Now, we conducted the experiment of 

X-band ESR measurement in the condition similar to the experiment by Morgunov et al., and 

performed the detailed spectrum analyses: In order to reproduce the main ESR spectra, at least 

two Lorentz spectra are required, and the multiplicity was explained by assuming the existence 

of two characteristic modes when each periodicity is defined as f or f’ (< f), there is a relation of 

f = 2f’. We consider that the magnetic fine structure originates from the existence of at least two 

nonequivalent magnetic sites owing to the diaminopropane with electric dipole moment. 

[1] R. Morgunov et al., Phys. Rev. B 77 (2008) 184419. 

PG11 

Valence and spin structures of TFe2O4 spinel oxides (T=Mn, Co, Ni, 

Cu) investigated by using synchrotron radiation 

Jihoon Hwang 1 , D. H. Kim 1 , Eunsook Lee 1 , J.-s. Kang 1 , B.-g. Park 2 , J.-y. Kim 2 , S. W. 

Han 3 , S. C. Hong 3 , S. B. Kim 4 , Bongjae Kim 5 and B. I. Min 5 

1 Department of Physics, The Catholic University of Korea (CUK), Bucheon 420-743, Korea, Korea 

2 Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Korea, Korea 

3 Department of Physics, Ulsan University, Ulsan 680-749, Korea, Korea 

4 ACE center, Konyang University, Nonsan 320-711, Korea, Korea 

5 Department of Physics, POSTECH, Pohang 790-784, Korea, Korea 

AB 2O 4-type spinel oxides have attracted much attention because of the interesting physical phenomena, such as 

Jahn-Teller (JT) effects, multiferroic phenomena, and phase separations [1]. In normal spinels of AB 2O 4, A and 

B ions occupy the tetrahedral (Td) and octahedral (Oh) sites, respectively. When both A and B ions are magnetic 

ions, a ferrimagnetic (FiM) ordering is often observed because the A-B interaction is mainly antiferromagnetic. 

In this work, we have investigated the electronic structures of FiM spinels of TFe 2O 4 (T=Mn, Co, Ni, Cu) by 

employing soft x-ray absorption spectroscopy (XAS) and soft x-ray magnetic circular dichroism (XMCD). It is 

found that the valence states of Fe ions are nearly trivalent (-Fe 3+ ) and those of T ions are nearly divalent (-T 2+ ). 

The 2p XMCD spectra of MnFe 2O 4 show that the magnetic moments of Mn 2+ and Fe 3+ ions are antiparallel to 

each other. On the other hand, the magnetic moments of Co 2+ , Ni 2+ , and Cu 2+ ions are parallel to those of B(Oh)site 

Fe 3+ ions, but are antiparallel to those of A(Td)-site Fe 3+ ions, implying that Fe 3+ ions occupy both A and B 

sites while Co, Ni, Cu ions occupy mainly B sites. *Corresponding Author: kangjs@catholic.ac.kr 

[1] J.-S. Kang, et al., Phys. Rev. B 77, 035121 (2008). 

PG12 

Probing the distance dependence of the magnetic exchange interaction 

with atomic resolution 

Alexander Schwarz 1 *, Rene Schmidt 1 , Roland Wiesendanger 1 , Cesar Lazo 2 and Stefan 

Heinze 3 

1 Institute of Applied Physics, University of Hamburg, Germany 

2 Christian-Albrechts Universitat zu Kiel, Germany 

3 Christian-Albrechts-Universitat zu Kiel, Germany 

Quantifying strength and distance dependence of magnetic interactions between atoms is crucial 

to gain a deeper understanding of magnetic phenomena on the nanoscale. Magnetic exchange 

force microscopy (MExFM) [1] is a new and very versatile tool to study magnetism with atomic 

resolution in real space. It utilizes an atomically sharp magnetic tip at the free end of a cantilever 

to detect the short-ranged electron-mediated magnetic exchange interaction between tip apex and 

surface atoms. This force microscopy based technique can be employed to map spin structures 

of insulating [1] as well as conducting [2] magnetic samples with atomic resolution. Here we 

demonstrate that its spectroscopic mode, i.e., magnetic exchange force spectroscopy (MExFS), 

is able to measure the distance dependence of the magnetic exchange interaction in a very direct 

and elegant fashion [3]. Results obtained on the antiferromagnetic Fe monolayer on W(001) are 

compared with theoretical calculations based on density functional theory. They were performed 

for realistic multiatom tips and agree very well with data acquired using non-dissipative stable tips. 

[1] U. Kaiser, A. Schwarz, and R. Wiesendanger, Nature 446, 522 (2007). [2] R. Schmidt, C. Lazo, H. 

Holscher, U. H. Pi, V. Caciuc, A. Schwarz, R. Wiesendanger, and S. Heinze, Nano. Lett. 9, 200 (2009). [3] R. 

Schmidt, C. Lazo, U. Kaiser, A. Schwarz, S. Heinze, and R. Wiesendanger, Phys. Rev. Lett. 106, 257202 (2011). 


PG13 

Electron correlation in a mixed valence perovskite system of Sr 1xCa 

xRu 0.5Mn 0.5O 3 

Tomohiro Ohnishi 1 , Soichiro Mizusaki 1 , Makoto Naito 1 , Yoshihiko Noro 2 , Masayoshi 

Itou 3 , Yoshiharu Sakurai 3 and Yujiro Nagata 1 

1 Electrical Engineering and Electronics, Aoyama Gakuin Univ., Japan 

2 Kawazoe Frontier Technologies Co. Ltd., Japan 

3 Japan Synchrotron Radiation Research Institute, Japan 

Mixed valence systems are interesting for their fundamental and practical properties. Perovskite-type 

oxides Sr 1-xCa xRu 1-yMn yO 3 is a typical mixed valence system.¹ The host itinerant system Sr 1-xCa xRuO 3 

shows various interesting properties such as ferromagnetism and paramagnetism.²,³ Mn-substitution 

induces a mixed valence state of Ru 4+ , Ru 5+ , Mn 4+ and Mn 3+ ions and localized ferromagnetism.¹, 4 However, 

understanding of the electron correlation in the mixed valence systems is not yet enough. In this work, 

we studied the relationship between electron correlation and mixed valence state through the experiments 

for Sr 1-xCa xRu 0.5Mn 0.5O 3 using the traditional experimental methods and the synchrotron-based magnetic 

Compton scattering. Sr 1-xCa xRu 0.5Mn 0.5O 3 is a good system since the Ca-substitution will modify crystal 

symmetry and change the electron correlation. The following results have been obtained; 1. Cell volume 

decrease for Ca substitution. 2. insulator-metal transition occurs for Ca substitution. 3. Ferromagnetism 

appears at x ~ 0.3. 4. Antiferromagnetic coupling between Ru and Mn. These facts can be explained as 

follows. The decrease in the cell volume enhances the hybridization between Ru and O orbitals inducing 

itinerant electrons. The itinerant electrons enhance the formation of a ferromagnetic order of Ru ions. Mn 

ions couples antiferromagnetically with Ru ions by a superexchange interaction via O 2p orbitals. 

1. M. Naito et al., J. Appl. Phys. 103 (2008) 07C906-1. 2. A. Kanbayashi, J. Phys. Soc. Jpn. 44 (1978) 108. 3. 

T. Kiyama et al. Phys. Rev. B 54 (1996) R756. 4. T. Taniguchi et al. Phys. Rev. B 77 (2008) 014406-1. 

PG14 

An x-ray scattering study of magnetic order in a pyrochlore iridate 

Eu 2Ir 2O 7 

Daisuke Uematsu 1 *, Hajime Sagayama 1 , Taka-hisa Arima 1 , Jun J Ishikawa 2 and 

Satoru Nakatsuji 2 

1 Department of Advanced Materials Science, The University of Tokyo, Japan 

2 Institute of Solid State Physics, The University of Tokyo, Japan 

The pyrochlore iridate Eu 2Ir 2O 7 undergoes a metal-insulator transition at T_{MI} = 120 

K [1]. Since the magnetic Ir 4+ ions occupy the pyrochlore B-site, strong geometrical 

spin frustration is predicted.Nevertheless, a muon spin rotation study [2] indicated 

long-range orderings spins of Ir 4+ . To determine the spin configuration, we have 

performed the resonant X-ray diffraction measurement at the LIII edge of Ir. A clear 

magnetic reflection was found at (10,0,0) below T_{MI}. The result proposes the allin-all-out-type 

magnetic structure. 

[1] K. Matsuhira et al., J. Phys. Soc. Jpn. 76, 043706 (2007). [2] S. Zhao et al., Phys. Rev. B. 83, 

180402 (2011). 

PG15 

Magnetic structure analyses by small-angle electron diffraction 

Yoshihiko Togawa 1 *, Tsukasa Koyama 2 , Shigeo Mori 2 and Ken Harada 2 

1 

Nanoscience and Nanotechnology Research Center (N2RC), Osaka Prefecture 


2 

Department of Materials Science, Osaka Prefecture University, Japan 

Electrons are deflected at small angles by Lorentz force in magnetic materials. In magnetic 

elements in functional materials and spintronic devices, observation of Lorentz deflection of 

electrons at the small angle turns to be of significance because Lorentz deflection angle of 

electrons becomes smaller in modern miniaturized magnetic devices composed of thinner 

magnetic films. In the present work, electron optical system is constructed in order to obtain 

small angle diffraction and Lorentz deflection of electrons at the order of down to 10-6 

radian in the reciprocal space[1]. Long-distance camera length up to 3000 m is achieved 

in a conventional transmission electron microscope with LaB6 thermal emission type. 

The diffraction pattern at 5 × 10-6 radian is presented in a carbon replica grating with 500 

nm lattice spacing while the magnetic deflection pattern at 2 × 10-5 radian is exhibited in 

Permalloy elements. A simultaneous recording of electron diffraction and Lorentz deflection 

is also demonstrated in 180 degree striped magnetic domains of La 0.825Sr 0.175MnO 3[2]. 

We believe that small-angle Bragg diffraction and Lorentz deflection analyses provide a 

quantitative way to analyze structural and magnetic properties in the reciprocal space. This 

study is partly supported by SCOPE project from the MIC in Japan. 

[1] T. Koyama, K. Takayanagi, Y. Togawa, S. Mori, and K. Harada, submitted. [2] T. Koyama, Y. 

Togawa, K. Takenaka, and S. Mori, to appear in J. Appl. Phys.

PG16 

Raman scattering of metal-insulator transition in Cd2Os2O7 Takumi Hasegawa 1 *, Norio Ogita 1 , Jun-ichi Yamaura 2 , Zenji Hiroi 2 and Masayuki 

Udagawa 1 

1 

Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi- 

Hiroshima, Hiroshima 739-8521, Japan 

2 

Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, 

Japan 

Cd 2Os 2O 7 is a pyrochlore oxide showing metallic behavior at room temperature, 

and it shows metal-insulator transition at 225 K [1]. It has been suggested that this 

metal-insulator transition is caused by magnetic order [1,2], because any superlattice 

reflection has not been observed by x-ray and neutron [3] diffraction measurements. 

However, to conclude no structural distortion precisely below the transition 

temperature, it is necessary to perform symmetry sensitive measurements rather 

than diffractions. Raman scattering method is a sensitive tool to observe small lattice 

distortion with symmetry breaking. We have measured Raman spectra of Cd 2Os 2O 7 

from 4 K to 300 K to investigate possibility of structural distortion in the insulator 

phase. Below the transition temperature, we have not observed any new peak indicating 

symmetry breaking from the pyrochlore structure with the space group Fd3m. 

[1] A. W. Sleight, J. L. Gillson, J. F. Weiher and W. Bindloss, Solid State Commun. 14, 357(1974). [2] 

D. Mandrus, et al., Phys. Rev. B 63, 195104(2001). [3] J. Reading and M. T. Weller, J. Mater. Chem. 

11, 2373(2001). 

PG17 

Effects of impurities in the chromic compound CuMoO 4 

Takayuki Asano 1 *, Taizo Nishimura 1 , Katsutaka Kubo 1 , Minoru Sanda 1 , Keisuke 

Matsuura 1 , Akira Matsuo 2 , Yasuo Narumi 3 and Koichi Kindo 2 

1 Department of Physcs, Kyushu University, Japan 


3 Institute for Materials Research, Tohoku University, Japan 

Recently interest in “Chromism” phenomena for compounds may be attributed to 

the fact that a reversible color change of organic and inorganic materials can occur as 

the compound experiences various changes in its environmental conditions. Copper 

molybdate, CuMoO 4, has demonstrated attractive properties of both thermochromism 

and piezochromism that are induced by a structural phase transition. We report a 

tunable structural phase transition and magnetic phenomena using substitutional effects 

in Cu 1-xZn xMoO 4(0≤x≤0.1), CuMo 1-yW yO4(0≤y≤0.1), and CuMo 1-zCr zO4(0≤z≤0.1) over 

wide ranges of temperatures and magnetic fields. The substitution of magnetic Cu 2+ 

ions for nonmagnetic Zn 2+ ions causes the hysteresis in the structural phase transition 

to shift to remarkably lower temperatures as x increases by means of magnetic 

susceptibility measurement. In contrast, replacing Mo 6+ ions with W 6+ ions results 

in a shift of the hysteresis and the structural phase transition to higher temperatures 

as y increases. However, in the case of replacing the Mo 6+ ions with Cr 6+ ions, the 

structural phase transition around 200K is completely disappeared and a ferromagnetic 

component is induced below 150K as z increases. We are going to discuss the reason 

of the shifting structural phase transitions and also show the magnetic properties under 

extreme conditions. 

PG18 

Effective exchange interactions in 5d transition metal oxides 

Tomonori Shirakawa*, Hiroshi Watanabe and Seiji Yunoki 

Computational Condensed Matter Physics Laboratory, RIKEN, Japan 

5d transition metal oxides, Sr 2IrO 4 and Ba 2IrO 4, have attracted much attention 

because of their unique properties caused by a strong spin-orbit coupling for 5d 

transition element. Both of these compounds behave as Jeff=1/2 Mott insulator at low 

temperature [1,2,3]. Recently, these compounds are expected to be a superconductor 

as an analogous system to high-Tc cuprates. According to recent experimental results 

on magnetic susceptibility and μSR studies, the effective exchange interactions in 

Sr 2IrO 4 and Ba 2IrO 4 are expected to be very large, and comparable to the ones of high- 

Tc cuprates [3]. Motivated by these experiments, we have studied theoretically the 

electronic and magnetic properties of Sr 2IrO 4 and Ba 2IrO 4 using a three-band Hubbard 

model with the spin-orbit coupling [4]. We first obtain the phase diagram of 8-site 

cluster in a wide parameter region using exact diagonalization technique. We find that 

there are several phases including the Jeff=1/2 Mott insulating phase which is realized 

in Sr 2IrO 4 and Ba 2IrO 4. We then calculate the dynamical spin structure factor composed 

by the Jeff=1/2 state in the Jeff=1/2 Mott insulating phase. We then estimate the 

values of effective exchange interactions by comparing the results with the ones of an 

effective spin model. 

[1] B. J. Kim et al., Science 323 (2009) 1329. [2] B. J. Kim et al., Phys. Rev. Lett. 101 (2008) 

076402. [3] H. Okabe et al., Phys. Rev. B 83 (2011) 155118. [4] H. Watanabe et al., Phys. Rev. Lett. 

105 (2010) 216410. 

PG19 

PG20 

PG21 


Magnetic and electrical transport behavior of Ir substituted NiTi 

shape memory alloy 

Sandhya Dwevedi* and A.k Nigam 

Department of Condensed Matter Physics and Material Sciences, Tata Institute of 

Fundamental Research(TIFR), Mumbai 400 005, India, India 

NiTi shape memory alloys (SMAs) show attractive functional properties for a 

number of engineering and medical applications [1]. Recently. Somsen et.al [2] have 

synthesized the novel Ni-Ti-Ir alloys and have studied its structural properties. This 

motivates us to study the other properties of the alloy. In the present work, we have 

systematically studied the structural, kinetics, magnetic and transport properties of the 

Ni-Ti-Ir alloy. The alloy is formed in the B2- type phase with a small amount of Ti 2NiIr 

as an additional phase. In the DSC curve, two distinct peaks are observed on heating 

and cooling. These peaks correspond to the Martensitic transformations (MT) from 

the B2 to R-phase and from R to B19’-phase on cooling and, a reverse transformation 

from B19’-R-B2 phase on heating, respectively. From the temperature dependence of 

resistivity curve, the Martensitic Start (MS), Martensitic Finish (Mf), Austenite Start (AS) 

and Austenite Finish (Af) temperatures are found to be 193 K, 153 K, 267 K and 293 K 

respectively. In the Magnetization versus temperature (M-T) curve, no evidence of the 

ferromagnetic ordering temperature is observed. However, the Magnetization versus 

Field (M-H) curve at 5 K and 300 K shows existence of ferromagnetic order in the alloy. 

[1]K. Otsuka, C. M. Wayman, Shape Memory Materials(Cambridge University Press) [2]Ch. 

Somsen, J. Khalil-AllaFib, E.P. George, Mater. Sci. Eng. A, 378, 170-174 (2004) 

X-ray diffuse scattering of pyrochlore niobium oxides R 2Nb 2O 7 

Shingo Toyoda 1 , Hajime Sagayama 1 , Kunihisa Sugimoto 2 and Takahisa Arima 1 * 


2 SPring-8, Japan 

It was reported that Y 2Nb 2O 7 is a non-magnetic insulator, although the electron 

configuration of Nb 4+ is 4d1 with S=1/2. To reveal the origin, we have performed 

X-ray scattering measurement of single crystals of R 2Nb 2O 7 (R=Y,Sm,Dy,and Ho). All 

the compounds show diffuse scattering, indicating that there exists short-range order. 

Analysis of the average structure suggests that Nb ions are displaced along the (111) 

direction. The formation of spin-singlet tetramers cannot explain the observed diffuse 

pattern. The short-range correlation implies the formation of spin-singret dimmers, 

because the configuration of dimmers in a pyrochlore latiice can be mapped on the icerule 

problem. In addition, the diffuse pattern changes with R. The diffuse of Y 2Nb 2O 7 is 

the broadest, while that of Dy 2Nb 2O 7 is narrowest and almost spot. 

[1] H. Fukazawa , Y. Maeno, Phys. Rev. B 67, 054410 (2003) 

Freezing of local lattice strains in the magnetic martensitic/ferroelastic 

material system 

Yu Wang*, Chonghui Huang, Xiaoping Song and Xiaobing Ren 

Xi'an Jiaotong University, China 

Glass state is a frozen disordered state, in which the long range order is destroyed 

but short range order persists. Recently, a new glass phenomenon called strain glass 

was found in the martensitic/ferroelastic material system [1]. The strain glass state 

is a frozen disordered state of local lattice strains (nanosized martensitic/ferroelastic 

domains). Experimental measurements show that strain glass possesses obvious glassy 

features including dynamic freezing and breaking down of ergodicity in its mechanical 

properties [1, 2], being similar to the glassy features of the cluster-spin glass with 

froze local spin order. Strain glass can be obtained by doping point defects into normal 

martensitic/ferroelastic system [1]. However, whether strain glass can be achieved 

in the defect doped magnetic martensitic/ferroelastic system is unknown so far. In 

this study, we report that a strain glass transition with freezing of local lattice strains 

can exist in the Co doped magnetic martensitic system Ni-Mn-Ga by using dynamic 

mechanical analysis. Moreover, our magnetic measurements show that the strain glass 

in the Co doped Ni-Mn-Ga system is ferromagnetic, which is a new form of strain 

glass. The finding of the strain glass in magnetic martensitic/ferroelastic system may 

lead to novel applications. 

[1] S. Sarkar, X. Ren and K. Otsuka, Phys. Rev. Lett. 95, 205702(2005) [2] Y. Wang, X. Ren, K. 

Otsuka, and A. Saxena, Phys. Rev. B 76, 132201(2007) 




PG22 


Magnetic structure of the new chiral compound [Cr(CN) 6][Mn(S)pnH(DFM)](H 

2O) 

Cristina Saenz De Pipaon 1 , Javier Campo 1 *, Fernando Palacio 1 , Jose Alberto 

Rodriguez-velamazan 1 , Katsuya Inoue 2 and Hiroyuki Honda 2 

1 Materials Science Institute of Aragon (CSIC-University of Zaragoza), Spain 

2 Hiroshima University, Japan 

Research on magnetic molecular materials has received strong attention in the last years for 

several reasons, among them, the possibility of these materials to be multifunctional, thus 

exhibiting more than one functional property at the same time. A very interesting possibility in 

a molecular material is magneto-chirality. Despite this interest, very few molecular candidates 

with likely possibilities have been synthesized, because chirality must be controlled in the 

molecular structure and at the same time the crystal must exhibit nuclear chirality. In addition, 

the arrangement of the magnetic moments must also be chiral. Nowadays, single crystals of 

the cyano-bridged bimetallic complexes have been growth, a 2D chiral ferrimagnet [Cr(CN) 6] 

[Mn(R)-pnH(DMF)]•(2H 2O) (1) and a racemic one [Cr(CN) 6][Mn(rac)-pnH(DMF)]•(2H 2O) 

(2), where DFM is N,N-dimethylformamide. Compound 1 consists of two-dimensional 

bimetallic sheets, with the same space group P212121, whereas compound 2 crystallizes under 

Pnma [1]. These compounds have been studied employing neutron diffraction techniques at the 

Institute Laue Langevin. In this communication, we present the nuclear and magnetic structures 

for (1) and (2). The coexistence of nuclear and magnetic chirality has been demonstrated. 

[1] H. Imai, K. Inoue, K. Kikuchi, Polyhedron 24, 2808-2812(2005) 

PG23 

Origin of spin scalar chiral order in frustrated Kondo lattice model 

- higher-order Kohn anomaly and hidden positive biquadratic 

interaction - 

Yutaka Akagi 1 *, Masafumi Udagawa 2 and Yukitoshi Motome 1 

1 University of Tokyo, Japan 

2 University of Tokyo, MPI PKS, Japan 

Recently, noncoplanar spin configurations with scalar chirality have drawn considerable attention as an 

origin of the anomalous Hall effect. In this mechanism, itinerant electrons acquire an internal magnetic 

field through the Berry phase according to the solid angle spanned by three spins, which can result in the 

anomalous Hall effect. In order to clarify how such nontrivial magnetic states appear in spin-charge coupled 

systems, we investigate a ferromagnetic Kondo lattice model on a triangular lattice by variational and 

perturbative calculations. As a result, we find that a noncoplanar four-sublattice spin ordering emerges near 

1/4-filling [1], in a wider parameter region compared to the nesting-driven 3/4-filling phase predicted in the 

previous study. We unveil that a kinetic-driven positive biqaudratic interaction is critically enhanced and 

plays a crucial role on stabilizing a chiral ordering near 1/4-filling. The origin of large positive biquadratic 

interaction is ascribed to the Fermi surface connection by the four-sublattice ordering wave vectors, which 

we call the higher-order Kohn anomaly [2]. Similar hidden interactions and resultant noncoplanar states 

are also found in other frustrated lattices, such as fcc and pyrochlore lattices. Our results suggest a universal 

mechanism underlying nontrivial spin configurations in frustrated spin-charge coupled systems. 

[1] Y. Akagi and Y. Motome, J. Phys. Soc. Jpn. 79 (2010) 083711. [2] Y. Akagi, M. Udagawa, and Y. 

Motome, preprint (arXiv:1201.3053), accepted for publication in Phys. Rev. Lett. 

PG24 

Doping effects on the metal-insulator transition of Li2RuO3 Seongil Choi 1 , Junghwan Park 1 , Sanghyun Lee 1 , Deo-kyong Cho 1 , T. Morioka 2 , H. 

Nojiri 2 and J.- G. Park 3 * 

1 

Center for Strongly Correlated Materials Research, Seoul National University, Seoul 

151-742, Korea 

2 

Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan 

3 

Department of Physics & Astronomy, Seoul National University, Seoul 151-742, 

Korea 

Li 2RuO 3 has a layered rocksalt-type structure and has attracted much attention 

because of its interesting physical properties. In particular, it exhibits a metal-insulator 

transition at a very high temperature around 540 K. At the same temperature, the 

magnetic susceptibility shows a big drop implying the formation of a spin gap. It is also 

interesting to note that all of these physical properties occur on the unusual honeycomb 

lattice of Ru ions. In order to understand the origin of the metal-insulator transition and 

its related physical properties better, we have carried some extensive studies ranging 

from bulk properties to neutron scattering experiments. First, we have investigated the 

doping effects on the metal-insulator transition by varying Li content. Second, we have 

examined the field dependence of the physical properties by measuring resistivity and 

magnetization over a wide temperature range. In this report, we are going to summarize 

our experimental results and its importance with respect to the reported metal-insulator 

transition. 


PG25 

Ferromagnetism in hydrothermally treated glassy carbon 

Hyun Jin Cho, Kyu Won Lee and Cheol Eui Lee* 

Department of physics and institute for Nano Science, Korea University, Korea 

We have investigated the magnetic properties of pristine and hydrothermal-treated 

glassy carbon by means of superconducting quantum interference device (SQUID) 

and electron spin resonance (ESR) measurements. The magnetic properties of the 

hydrothermally treated glassy carbon showed a sensitive dependence on the solvents 

and the treatment time. In particular, prominent ferromagnetism was observed in 

samples hydrothermally treated in ethanol for a properly chosen time, with the 

saturation moment and coercive force being comparable to those of iron. The 

ferromagnetism in the hydrothermally treated glassy carbon may have to do with the 

relative fractions of the sp3- and sp2-bonds. 

[1] X Wang et al 2002 J. Phys.: Condens. Matter 14 10265 

PG26 

On the structure and symmetry of the spin glass state (SGS) 

Jerzy Warczewski*, Pawel Gusin and Daniel Wojcieszyk 

Institute of Physics, University of Silesia, Poland 

The explanation of uniqueness of SGS has roots in the appearance of a certain 

probability function in the second term of the assumed Hamiltonian [1, 2]. This term 

describes the random distribution of either dopants or defects in the ferromagnetic 

matrix under the percolation threshold. The Gaussian type randomness was derived for 

both the global magnetic coupling constant and the magnetization vector M, the latter 

effect bringing to the statistical features of the magnetic structure and the magnetic 

symmetry group of SGS. In both cases the use has been made of the central limit 

theorem of the theory of probability (the Lyapunov theorem) [3]. The authors have 

earlier proved that a certain spontaneous minimum magnetic field H is necessary for 

the stability of SGS [4]. The structure of SGS can then be described in such a way that 

M is situated along a generatrix of a given cone whose axis coincides with the direction 

of H [4]. Let us call φ the angle between M and H. Any precession of M around the 

direction of H at φ = const (at constant energy) makes the symmetry operation of SGS. 

Thus the symmetry group of this precession is SO(2) [3]. 

[1] J. Warczewski, P. Gusin et al., Journal of Non-Linear Optics, Quantum Optics 30 (2003), 301- 

320 [2] P. Gusin, J. Warczewski, Mol. Cryst. Liq. Cryst. 521 (2010), 288-292 [3] J. Warczewski, P. 

Gusin, D. Wojcieszyk, Mol. Cryst. Liq. Cryst. 554 (2012), 209-220 [4] J. Warczewski, P. Gusin et al., 

J. Phys.: Condens. Matter, 21 (2009), 035402-035407 

PG27 

Magnetic study of Fe/MgO/Fe and Fe/MgO/Fe/Co multilayer systems 

Jitendra Pal Singh 1 , Sanjeev Gautam 2 , K Asokan 1 , D. Kabiraj 1 , D. Kanjilal 1 , M Raju 3 , 

Braj Bhusan Singh 4 , S. Chaudhary 3 , R. Kotnala 4 and Keun Hwa Chae 2 * 

1 Inter University Accelerator Centre, Aruna Asaf Ali Marg-110067, New Delhi, India 

2 Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea 

3 Department of Physics, Indian Institute of Technology, New Delhi - 110 016, India 

4 National Physical Laboratory, Dr. K. A. Krishanan Marg, New Delhi -110 012, India 

Theoretical calculations [1-3] show high TMR up to 1000% for Fe/MgO/Fe MTJ’s however TMR ratios of 

200% at room temperature could be realized in these systems [4]. The discrepancy between theoretical and 

experimental values of TMR is probably due to the interface properties of the heterostructures, as spin dependent 

tunneling is sensitive to the interface [3]. In present work, we investigated the magnetic properties of Fe/MgO/ 

Fe (MFe) and Fe/MgO/Fe/Co (MFeCO) multilayers by vibrating sample magnetometer (VSM) deposited by 

electron beam evaporation method [6]. Attributes of perpendicular magnetic anisotropy (PMA) are observed 

in MFe multilayer. The PMA arises due to Fe(3d) and O (2p) hybridization at metal-oxide layer interface and 

generally observed in MTJs [6]. The asymmetric coercivity observed in this structure is due to the presence of 

exchange bias which arises probably due to oxidation of Fe at surface; resulting in antiferromagnetic Fe 2O 3. The 

positive vertical shift along magnetization axis may be due to the pinned interfacial uncompensated spins of 

unwantedly formed Fe 2O 3 [7]. Apart from this MFeCo multilayer do not exhibit any feature observed in MFe 

multilayers. The absence of these is expected almost 3 times increase of Fe layers in MFeCo system [5]. 

References: 1. A. Lyle, et al. App. Phys. Lett. 97 152504 (2010) 2. J-G. Zhu and C. Park, Materials Today, 9 36 (2006) 3. J. 

Mathon and A. Umerski, Phys. Rev. B 63 220403 (2001). 4. S.S.P. Parkin, , et al., Nat Mater, 3 862 (2004) 5. J. P. Singh et al., 

AIP Conf. Proc. (in Press) 6. S. Ikeda et al. Nature Mater. 9 (2010) 721-722 7. H. Ohldag et.al. Phy. Rev. Lett., 91, 017203, 2003

PH01 

Ionic size effect on the spin gap nature of SrCu 2(TeO 3) 2Cl 2 

C. N. Kuo, S. C. Chen and C. S. Lue* 

Department of physics,, National Cheng Kung University, Tainan 70101, Taiwan, 

Taiwan 

We report the effects of partial substitution of Br onto the Cl sites of SrCu 2(TeO 3) 2Cl 2 

by means of magnetic susceptibility measurements. This material has been a subject 

of current interest due to indications of spin gap behavior. However, the magnetic spin 

couplings responsible for the spin gap nature remains unclear. For each composition of 

SrCu 2(TeO 3) 2(C l1-xBr x) 2, the temperature-dependent susceptibility exhibits a character 

of low-dimensional magnetism with a broad maximum at Tmax. The magnitude 

of Tmax gradually shifts to higher temperatures as increasing the Br concentration. 

The experimental data can be well fitted to a coupled spin dimer model, yielding an 

increasing trend for the spin gap size from 170 K to 190 K. It thus points out that 

the substitution of Br ions has an effect to reduce the distance between Cu(1) and 

Cu(2), leading to a stronger antiferromagnetic spin interaction. On the other hand, 

the variation of the interdimer coupling is marginal, indicative of weak effects on the 

distances of Cu(1)-Cu(1) and Cu(2)-Cu(2) in SrCu 2(TeO 3) 2Cl 2. 

PH02 

Magnetism of SrM 3P 4O 14 (M 2+ = 3d ions) investigated using neutronscattering 

measurements 

Masashi Hase 1 *, Vladimir Yu. Pomjakushin 2 , Lukas Keller 2 , Andreas Doenni 1 , 

Osamu Sakai 1 , Tao Yang 3 , Rihong Cong 3 , Jianhua Lin 3 , Kiyoshi Ozawa 1 and Hideaki 

Kitazawa 1 

1 National Institute for Materials Science (NIMS), Japan 

2 Paul Scherrer Institut (PSI), Switzerland 

3 Peking University, China 

One of intriguing phenomena in magnetism is appearance of qualitatively different magnetism 

in isostructural substances. In AM 3P 4O 14 (A = Ca, Sr, Ba or Pb, M 2+ = Ni 2+ : spin-1, Co 2+ : spin- 

3/2, Fe 2+ : spin-2 or Mn 2+ : spin-5/2), magnetism in AMn 3P 4O 14 is qualitatively different from 

magnetism in the other substances. A 1/3 quantum magnetization plateau was observed only 

in AMn 3P 4O 14. An antiferromagnetic (AFM) long-range order (LRO) without a spontaneous 

magnetization appears in AMn 3P 4O 14, while a canted AFM LRO appears in the other 

substances. We studied magnetism of SrM 3P 4O 14 using neutron-scattering measurements. In 

SrMn 3P 4O 14, we determined the coplanar spiral magnetic structure that had no spontaneous 

magnetization. We confirm that the spin system is a frustrated J1-J1-J2 trimerized spin chain 

with dominant AFM J1, small AFM J2, and small next-nearest-neighbor exchange interactions. 

The magnetization plateau is possible. In SrM 3P 4O 14 (M = Co or Ni), we determined the canted 

magnetic structure (the irreducible representation tau1 in the space group P21/c). We consider 

that the spin system consists of ferromagnetic dimers formed by the dominant J2 interaction 

and monomers. The magnetization plateau is impossible. 

PH03 

Spin-Peierls-like lattice distortion and incommensurate magnetic 

structure of geometrically frustrated spinel CdCr 2O 4 

J.- H. Chung 1 , J. M. S. Park 2 , K.- P. Hong 2 , M. Matsuda 3 , H. Ueda 4 , Y. Ueda 4 and S.- H. 

Lee 5 * 

1 Department of Physics, Korea University, Korea 

2 Korea Atomic Energy Research Institute, Korea 

3 Oak Ridge National Laboratory, Korea 

4 The University of Tokyo, Japan 

5 University of Virginia, USA 

ACr 2O 4 spinels (A = Zn, Cd, Hg) with antiferromagnetic Cr 3+ (S = 3/2) on B sites are well known for 

strong geometrical frustration preventing long-range order. The frustrations in their cubic phases are 

finally lifted via spin-Peierls-like lattice distortions at low temperatures. In spite of their similarities 

in the cubic phases, each of them undergo distinctive lattice distortions and exhibit unique magnetic 

order. The nature of their magnetic ground states is thus of great importance in order to understand 

these novel transitions. Nevertheless, the exact spin structure of CdCr 2O 4 has so far never been 

reported. We revisited this issue by performing neutron powder diffraction measurement of isotopeenriched 

sample for reduced neutron absorption. We observed the cubic-to-tetragonal distortion and 

the subsequent incommensurate magnetic order that are consistent with previous reports. Using 

representation analysis, we found that the spins on different sublattices maintain nearly collinear 

arrangements within a single tetrahedron. Whereas the obtained spin structure is different from 

the one previously conjectured based on spin wave frequencies, it is consistent with the idea that 

quantum fluctuation plays an important role in the magnetic ground state of CdCr 2O 4. 

PH04 

PH05 

PH06 


Interplay of magnetic order and structural distortions in multiferroic 

GdMnO 3 single crystals 

Mathias Doerr 1 *, Sahana Roessler 2 , Martin Rotter 2 , Aditya A. Wagh 3 , P. S. Anil 

Kumar 3 , Suja Elizabeth 3 , Steffen Wirth 2 and Michael Loewenhaupt 1 

1 Institut fur Festkorperphysik (IFP), Technische Universitat Dresden, Germany 

2 Max-Planck-Institut fur Chemische Physik fester Stoffe Dresden, Germany 

3 Department of Physics, Indian Institute of Science Bangalore, India 

Multiferroics are candidates for magneto-electrical applications. Magnetic and dielectric phenomena 

in orthorhombic GdMnO 3 are strongly intertwined. In addition, electrically induced magnons exist. 

Magnetostriction measurements by high-resolution capacitive dilatometry, performed in the different 

AFM phases below T N = 42 K, show lattice distortions with striction of about 10 -4 . All longitudinal 

and transversal components of the magnetostriction tensor were measured for the first time. Although 

no changes of the lattice symmetry exist, the measurements reveal magneto-structural phenomena, 

especially in the canted-AFM phase. A strong anisotropy of the magnetoelastic properties was found, 

in good agreement with the type and propagation of the magnetic structure. As the capacitive method 

is sensitive to expansion effects and changes of permittivity, dielectric anomalies could be detected 

and compared to the critical values of H and T of the magnetic transitions. The anomalies especially 

exist in the range 10….22 K in which the structure is characterized by magnetic order on both the 

Gd- and Mn-sites. This demonstrates the strong interplay of magnetic, charge and lattice degrees of 

freedom. First steps in modelling the magnetization of GdMnO 3 by the simulation program McPhase 

are presented and exchange mechanisms are discussed. These results are examined in connection 

with the magnetostriction data. 

Uniaxial pressure effect on magnetic ordering in a frustrated ising 

antiferromagnet CoNb 2O 6 

Satoru Kobayashi 1 *, Hiromu Tamatsukuri 2 , Chikafumi Kaneko 2 , Yuki Honma 2 , Taro 

Nakajima 2 and Setsuo Mitsuda 2 

1 Department of Materials Science and Engineering, Iwate University, Japan 

2 Department of Physics, Faculty of Science, Tokyo University of Science, Japan 

Uniaxial pressure effect on magnetic ordering has been investigated by magnetization 

measurements for a frustrated Ising antiferromagnet CoNb 2O 6 where quasi-onedimensional 

ferromagnetic chains along the c axis form a frustrated isosceles triangular 

lattice on the a-b plane. Under uniaxial pressure and magnetic field along the a axis, a 

critical field of magnetic phase transitions from antiferromagnetic to incommensurate 

magnetic (ICM) phase as well as from ICM to ferromagnetic phase monotonically 

increases, indicating the strengthening of antiferromagnetic interchain exchange 

interactions. Above 700 MPa, a step-like behavior of the magnetization curve shows 

up at around the half of the saturation magnetization. This behavior implies the 

appearance of a pressure-induced magnetically ordered phase characterized by the 

propagation wave vector of qM=(0,0.5,0) and/or (0,0.25,0). These observations were 

explained within mean field calculations with nearest-neighbor and next-nearestneighbor 

interchain exchange interactions. 

Thermal and magnetic properties of LiNiPO4 olivine 

J. Wieckowski 1 *, M. U. Gutowska 1 , A. Szewczyk 1 , Yu. Kharchenko 2 , M. F. 

Kharchenko 2 , M. Kowalczyk 3 , N. Nedelko 1 , S. Lewinska 1 , A. Slawska - Waniewska 1 , 

A. Kulka 4 and J. Molenda 4 

1 

Institute of Physics, Polish Academy of Sciences, Warsaw, Poland 

2 

B.Verkin Inst. for Low Temp. Phys. and Engineering, National Academy of Sciences 

of Ukraine, Kharkiv, Ukraine 

3 

Faculty of Materials Engineering, Warsaw University of Technology, Warsaw, 

Poland 

4 

Department of Hydrogen Energy, AGH University of Science and Technology, 

Cracow, Poland 

On the contrary to LiMPO 4 olivines with M = Mn, Fe, Co, in LiNiPO 4 two step transformation between 

the paramagnetic and a uniform in space antiferromagnetic phase occurs. At first, a long-range magnetic 

order develops in the form of an incommensurate antiferromagnetic phase (via a second-order transition at 

21.8 K) and then a first-order transition to the antiferromagnetic phase occurs at 20.9 K. To study thermal 

properties of LiNiPO 4, and an influence of magnetic field, B, on the magnetic structure, specific heat 

measurements of a single crystal were carried out from 3 K to 60 K, in B=0 and in B (up to 9 T) applied 

along three main crystallographic directions. It was found that B applied along a and b directions has no 

effect on the transitions, whereas B directed along c axis shifts both transitions towards lower temperatures 

(with the transition temperatures depending parabolically on B). To elucidate these effects, supplementary 

studies of magnetic torque were performed for several B values, for B rotating within a-c and b-c planes, 

for a series of fixed temperatures. This work was partly supported by the European Regional Development 

Fund, through the Innovative Economy Grants: POIG.01.01.02-00-108/09 and POIG.02.02.00-00-025/09. 




PH07 


Cr- and mo-doping effects on structural and orbital order phase 

transition in spinel-type MnV 2O 4 

Kazuhiro Hemmi 1*, Ryuichiro Fukuta 1, Ece Uykur 1, Shigeki Miyasaka 1, Setsuko 

Tajima 1, Akiko Nakao 2, Hironori Nakao 2, Reiji Kumai 2 and Youichi Murakami 2 

1 Physics, Osaka University, Japan 

2 PF/CMRC, KEK, Japan 

MnV 2O 4 has orbital degrees of freedom of t2g electrons in V 3+ (3d2), and undergoes magnetic 

and orbital order. In this study, we investigated the doping effects of Cr 3+ (3d3) and Mo 3+ (4d3), 

which have no orbital degrees of freedom, for the V 3+ site of MnV 2O 4, in order to clarify the Cr- 

and Mo-doping effect on the electronic properties in this system. In MnV 2O 4, the paramagnetic 

to collinear ferrimagnetic phase transition and the collinear to noncollinear ferrimagnetic phase 

transition occur at TN=59K and TOO=54K, respectively. The structural phase transition from 

cubic to tetragonal lattices takes place at TOO concomitantly with the orbital order. From the 

magnetic susceptibility and powder X-ray diffraction measurements, it is clarified that the orbital 

order is suppressed by Cr- and Mo-doping and disappears above x=0.12 (x=0.08) in Cr (Mo)doped 

samples. The resistivity and optical reflectivity measurements have clarified that the system 

becomes almost metallic with increasing Mo content, while the Cr-doped samples are still Mott 

insulators. These results indicate that the doped Cr and Mo with no orbital degrees of freedom 

suppress the orbital order in MnV 2O 4. The introduced 3d electrons remain localized in the Crdoped 

system, while 4d electrons become nearly itinerant in the Mo-doped one. 

R. Plumier and M. Sougi, Solid State Commun. 64, 53 (1987). S. Suzuki et al., Phys. Rev. Lett. 98, 127203 (2007). 

PH08 

Dopant-dependence on charge/orbital order in impurity doped layered 

manganites 

Yuki Yamaki 1 , Hironori Nakao 2 , Yuichi Yamasaki 2 , Youichi Murakami 2 , Yoshio 

Kaneko 3 and Yoshinori Tokura 4 

1 

Tohoku University CMRC/PF, KEK, Japan 

2 

CMRC/PF, KEK, Japan 

3 

ERATO-MF, JST CERG, RIKEN, Japan 

4 

ERATO-MF, JST CERG/CMRG, RIKEN University of Tokyo, Japan 

A layered manganite La 0.5Sr 1.5MnO 4 shows charge/orbital order and CE-type 

antiferromagnetic structure below 240 K and 110 K, respectively. We have studied how 

the ordering state is changed by the substitution of Cr, Fe and Ga ions for Mn ions using a 

resonant x-ray scattering (RXS) technique and magnetization measurement. In trivalent 

ions these impurity ions have no orbital degree of freedom and different spin values, 

in fact Cr 3+ , Fe 3+ , and Ga 3+ have S = 3/2, S = 5/2, and S = 0, respectively. As a result, 

the magnetization for Ga doped compound shows the same temperature dependence as 

pure compound, but in Cr and Fe doped compounds the magnetizations increase below 

90 K and 70 K, respectively. On the other hand, in all doped compounds the RXS 

intensities which reflect charge/orbital order are smaller than that in pure compound, 

but degrees of decrease are different according to the dopants. Namely, RXS intensity 

of Ga-doped compound has the same temperature dependence as pure compound, 

while RXS intensities of Cr- and Fe-doped compounds drastically decrease below 90 

K and 70 K, respectively. 

PH09 

Magnetic and nonmagnetic impurity effect on magnetic orderings of 

isosceles triangular lattice antiferromagnet CuMnO 2 

Noriki Terada 1 , Yoshinori Tsuchiya 1 , Hideaki Kitazawa 1 and Naoto Metoki 2 

1 National Institute for Materials Science, Japan 

2 Japan Atomic Research Agency, Japan 

In recent years, chemical substitution effect on magnetic and dielectric properties in frustrated magnetic 

systems has been a vast field of challenging new physics. Good illustrations are the drastic and various 

effects of a small level of chemical substitution upon the magnetic and dielectric properties on frustrated 

magnetic systems such as CuFeO 2 and MnWO 4. These magnetic ground states stabilized with 

strongly competing exchange interactions should be easily changed by slight chemical disturbance. 

In the present study, we have investigated magnetic and nonmagnetic impurity substitution effects on 

magnetic ordering of a frustrated isosceles triangular lattice antiferromagnet CuMnO 2 by means of 

the magnetic neutron diffraction measurements on Cu(Mn 1-xCu x)O 2 and Cu(Mn 1-yGa y)O 2. While the 

magnetic wave vector of Cu(Mn 1-xCu x)O 2 the magnetic ground state of ``magnetically' substituted with 

x=0.04 is Q=(-1/2 1/2 0)[1-3], that in the ``nonmagnetically' substituted Cu(Mn 1-yGa y)O 2 with y=0.05, 

0.15 and 0.20 is Q=(-1/2 1/2 1/2) that is identical to that of pure CuMnO 2. We discuss an influence of 

magnetic or nonmagnetic impurity substitution on the magnetic ordering of CuMnO 2, by comparing 

the results of Cu(Mn 1-yGa y)O 2 with Cu(Mn 1-xCu x)O 2. 

[1]N. Terada, Y. Tsuchiya, H. Kitazawa, T. Osakabe, N. Metoki, N. Igawa and K. Ohoyama, Phys. 

Rev. B 84 064432 (2011). [2]M. Poienar, C. Vecchini, G. Andre, A. Daoud-Aladine, I. Margiolaki, 

A. Maignan, A. Lappas, L. C. Chapon, M. Hervieu, F. Damay, and C. Martin, Chem. Mater. 23, 85 

(2011). [3]V. O. Garlea, A. T. Savici, and R. Jin, Phys. Rev. B 83, 172407 (2011). 


PH10 

Resonant soft X-ray scattering studies on half-doped manganite 

LaSr 2Mn 2O 7 

J.-s. Lee 1 *, C.-c. Kao 1 , C.s. Nelson 2 , H. Jang 3 , K.-t. Ko 3 , S.b. Kim 4 , Y.j. Choi 4 , S.w. 

Cheong 4 , S. Smadici 5 , P. Abbamonte 5 and J.-h. Park 3 

1 SSRL, SLAC National Accelerator Laboratory, USA 

2 BNL, USA 

3 POSTECH, Korea 

4 Rutgers university, USA 

5 UIUC, USA 

Recently, a careful doping control study, however, reported that the La 2-2xSr 1+2xMn 2O 7 

system has an exotic spin phase diagram very near the half doping with extremely 

narrow antiferromagnetic (AFM) phase boundaries at x ~ 0.5 +/- 0.005: the CEtype 

within the boundaries but the A-type outside. To elucidate complication of this 

spin phase diagram, we investigated the orbital and AFM ordering behaviors of the 

half-doped bilayer manganite LaSr 2Mn 2O 7 by using Mn L-edges resonant soft x-ray 

scattering. We confirmed the predicted CE-type AFM order for the true half-doped (x = 

0.5) case. Furthermore, we found that such a narrow phase boundary is due to the close 

competition of the two AFM phases via 3d Mn eg orbital instability. 

PH11 

On the non-idle-spin behavior and the field-induced magnetic 

transitions of the trimer chain magnet Cu 3(OH) 4SO 4 

Hyun-joo Koo 1 , Reinhard K Kremer 2 and Myung-hwan Whangbo 3 

1 Chemistry, Kyung Hee University, Korea 

2 Max-Planck-Institut fur Festkorperforschung, Stuttgart, Germany 

3 Chemistry, North Carolina State University, USA 

The magnetic properties of the Cu(2)-Cu(1)-Cu(2) trimer chain magnet Cu 3(OH) 4SO 4 

were examined by evaluating the spin exchange constants, the Dzyaloshinskii-Moriya 

(DM) vectors, and the magnetic anisotropy energies of the Cu(1) and Cu(2) sites on 

the basis of density functional calculations. Cu 3(OH) 4SO 4 is not a idle-spin magnet, 

the Cu(1) spins have a strong antiferromagnetic coupling in the Cu(1) chain, and the 

Cu(2) spin arrangements of a Cu(2)-Cu(1)-Cu(2) trimer chain result from the presence 

of two non-equivalent sets of AFM interactions between the Cu(1) and Cu(2) chains. 

We propose the probable spin arrangements of a trimer chain responsible for the fieldinduced 

successive magnetic transition, and suggest that the nature of the magnetic 

transition depends on the field-direction because of the DM interactions associated 

with two strong spin exchange paths. 

PH12 

Spin state of LaCoO 3 investigated from non-magnetic-ion substitution 

effect of Co sites 

Shinichiro Asai*, Ryuji Okazaki, Yukio Yasui and Ichiro Terasaki 

Department of Physics, Nagoya University, Japan 

The perovskite oxide LaCoO 3 is a fascinating material because of a dramatic change 

of its spin state with temperature variation. In low-temperature range, LaCoO 3 is nonmagnetic 

because the d electrons of Co 3+ (3d6) fully occupy the lower t2g orbitals (LS). 

On the other hand, the nature of its excited state is controversial. The spin state of this 

system is also sensitive to the chemical substitutions. Most interestingly, non-magnetic 

Rh 3+ (4d6: LS) substitution increases the magnetization at low temperature, which is 

different from Ga 3+ (3d10) substitution effect. We have measured the magnetization and 

x-ray diffraction of LaCo 1-xRh xO 3 [1]. We have found a weak ferromagnetic ordering 

for 0.1 < x < 0.4, indicating that the Rh substitution stabilizes the magnetic state of 

Co 3+ at low temperatures. The effective magnetic moment of LaCo 1-xRh xO 3 evaluated 

at room temperature is independent of x for 0 < x < 0.5, and rapidly decreases above 

x = 0.5. It indicates that the excited state of Co 3+ is well described as a mixture of the 

low- and the high-spin Co 3+ ions, and that a Rh 3+ ion favors to substitute for a low-spin 

Co 3+ ion. 

[1]. S. Asai et al.; J. Phys. Soc. Jpn. 80 (2011) 104705.

PH13 

First-Principles Calculation of the A-Site Ordered Perovskite 

CaCu 3Fe 4O 12 

Takuya Ueda 1 , Mitsuru Kodera 1 , Kunihiko Yamauchi 1 and Tamio Oguchi 2 * 


2 Osaka University & JST-CREST, Japan 

PH14 

PH15 

UPGRADED 

Soft x-ray absorption spectroscopy study of Prussian blue analogue 

MCo[Fe(CN) 6]H 2O Nano-particles (M=Na, K, Rb) 

Eunsook Lee 1 , D.h. Kim 1 , Jihoon Hwang 1 , Nguyen Van Minh 2 , In-sang Yang 3 , M. 

Sawada 4 , T. Ueno 4 and J.-s. Kang 1 * 

1 Department of Physics, The Catholic University of Korea, Bucheon 420-743, Korea 

2 Department of Physics, Hanoi National Uninersity of Education, Hanoi, Viet Nam 

3 Department of Physics, Ewha Womans University, Seoul 120-750, Korea 

4 Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan 

Molecular-based magnetic materials have been studied for their possible applications as nano-magnetic devices 

as well as for the understanding of the fundamental physics of their magnetic phenomena. Molecular magnetic 

materials of Prussian Blue (PB) analogues, which are represented by the general formula, An[B(CN) 6]m∙xH 2O, 

where A and B are transition-metal ions [1], show various characteristic magnetic properties depending on their 

transition metal ions. PB crystallizes in the fcc structure with space group Fm3m [2]. Of special interest is the 

photo-induced spin transition. However, the origin of the photo-induced spin transition has not been understood 

well yet. In this work, we have studied the valence states of PB analogue MCo[Fe(CN) 6]H 2O (M=Na, K, 

Rb) nano-size particles by employing synchrotron-radiation soft x-ray absorption spectroscopy (XAS). The 

measured Fe and Co 2p XAS spectra of MCo[Fe(CN) 6]H 2O (M=Na, K, Rb) reveal the systematic changes as 

the size of M ion changes, from the Fe 2+ -Fe 3+ mixed-valent states and the nearly divalent Co 2+ states to the nearly 

trivalent Fe 3+ states and the Co 2+ -Co 3+ mixed-valent states. This finding suggests that the electronic structures of 

PB nano-particles play an important role in determining their magnetic properties. 

[1] Amit Kumar and S M Yusuf, Pramana - J. Phys., 63, 239 (2004). [2] Nguyen Van Minh, Phung 

Kim Phu, Nguyen Minh Thuan, and In-Sang Yang, J. Magnetics, 13, 149 (2008). 

Long-time variation of magnetic structure in multistep metamagnets 

Ca 3(Co-M) 2O 6: Effect of disorder 

Taketo Moyoshi*, Rui Takahashi, Yuichiro Ito, Ryotaro Irie, Tetsuto Ide, Daiki Syoji 

and Kiyoichiro Motoya 

Faculty of Science and Technology, Tokyo University of Science, Japan 

We have reported that CeIr 3Si 2, Ca 3Co 2O 6 and some other materials show long-time variation 

of magnetic structure [1-4]. These materials are uniform compounds including no appreciable 

randomness or imperfections. All of these compounds show successive magnetic transitions 

and metamagnetic transitions at low magnetic field, which indicate the presence of competing 

magnetic interactions. Therefore, we think that the long-time variation of magnetic structure in 

these materials is caused by the competing magnetic interactions. To ensure that randomness 

or imperfections are not the main factor causing the long-time variation of magnetic structure, 

we have investigated the element substitution effects. In this presentation, we show the time 

dependence of the magnetization in Ca 3(Co 1-xM x) 2O 6 (M=Ga, Mg, Al and Ti). The time 

variations of magnetization were measured after the sample was cooled to various target 

temperatures from T=30 K (T>Tc1) at B=5 mT. Characteristics of the time variation behavior 

were not much modified by the disorder produced by the substitution of non-magnetic 

elements. These results show that the long-time variation of the magnetic structure in Ca 3Co 2O 6 

is not caused by randomness or imperfections. 

[1]K. Motoya et al. J. Phys. Conf. Series 200 (2010) 032048 [2]T. Moyoshi et al., J. Phys. Soc. Jpn. 

81 (2012) 014704 [3]T. Moyoshi and K. Motoya, J. Phys. Soc. Jpn., 80 (2011) 034701 [4]K. Motoya 

et al. J. Phys. Conf. Series 273 (2011) 012124 

PH16 

PH17 

PH18 


Study of magnetic properties of NdCo1-xNixO3 (x = 0, 0.2, 0.4) 

Ravi Kumar 1 , Vinod Kumar 2 , Rajesh Kumar 3 , Dinesh Kumar Shukla 4 , Sunil Kumar 

Arora 5 and I V Schvets 6 

1 

Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur 177005 (H.P.), 

India 

2 

Department of physics, National Institute of Technology, Hamirpur 177005 (H.P.), India 

3 

Department of physics, National Institute of Technology, Hamirpur 177005 (H.P.), India, India 

4 

Deutshes Electronen Synchrotron DESY, 22607 Hamburg, Germany, Deutshes Electronen Synchrotron 

DESY, 22607 Hamburg, Germany, Germany 

5 

School of Physics, Trinity College Dublin 2, 3School of Physics, Trinity College Dublin 2, Ireland 

6 

School of Physics, Trinity College Dublin 2, School of Physics, Trinity College Dublin 2, Ireland 

We report here the magnetization studies of the NdCo 1-xNi xO 3 (x = 0, 0.2, 0.4) samples 

synthesized using conventional solid state reaction method. X-ray diffraction followed 

by Rietveld refinement, confirms the single phase orthorhombic structure with Pbnm 

space group for all the samples. X-ray absorption spectroscopy studies revealed that both 

Co and Ni exist in trivalent state. The zero field cooled and field cooled magnetization 

measurements show that below room temperature the magnetization has strong influence 

of paramagnetic rare earth ion inhibiting magnetic ordering of cobalt ions. Below a 

certain low temperature (T< 50K), samples with x = 0, 0.2, show paramagnetic to anti 

ferromagnetic transition but the sample with x = 0.4 shows paramagnetic to Spin glass 

transition. Isothermal magnetization hysteresis measurements revealed the similar behavior 

at low temperature. The overall magnetic behavior has on the basis of various magnetic 

interactions between Nd-sublattice and those of transition metal networks. 

Fluctuations of charge, orbital, and spin order in single layer 

manganite Pr 0.5Ca 1.5MnO 4 

Ismudiati Puri Handayani 1 *, Agung Nugroho 2 , Nandang Mufti 3 , Syarif Riyadi 1 , May 

On Tjia 2 , T.t.m Palstra 1 and P.h.m Van Loosdrecht 1 

1 Zernike Institute for Advanced Material, Netherlands 

2 Bandung Institute of Technology, Indonesia 

3 State University of Malang, Indonesia 

The magnetic and transport properties of doped manganite oxides are intimately related to the 

dimensionality of the MnO 2 network. A three dimensional system tends to lead to metallicferromagnetic 

properties, whereas the two dimensional (2D) systems is dominated by chargeorbital 

order (COO) leading to insulating-antiferromagnetic properties. Pr 0.5Ca 1.5MnO 4 is one of 

the more interesting members of the 2D manganite family showing a charge and orbital ordering 

transition above room temperature (TCOO = 320 K) with distinct changes in the magnetic, 

transport, and structural properties, evidencing a strong coupling between the orbital, structural, 

charge, and spin degrees of freedom. We study the structural, magnetic susceptibility, transport, 

specific heat, and Raman spectroscopy of this material. The metal insulator transition observed 

at TCOO is found to be more pronounced in comparison to the well studied isostructural 

La 0.5Sr 1.5MnO 4 compound. The same holds for the changes in the magnetic susceptibility at the 

antiferromagnetic transition (TN=120 K). Even though the COO is accompanied by rather abrupt 

changes in the physical properties, our data shows that no full ordering occurs at the transition 

temperature. The system exhibits orbital fluctuations down to a temperature of about 200K, leading 

to an unusual temperature dependence of the vibrational, magnetization, and transport properties. 

Magnetic properties of spinel oxide CuCr 2O 4 investigated by NMR 

Euna Jo, Soonchil Lee*, Changsoo Kim, Byeongki Kang and Sangil Kwon 

Physics, KAIST, Korea 

Spinel oxide CuCr 2O 4 is known to have non-collinear spin structure and orbital 

ordering in its ground state. NMR spectrum for the magnetic ions Cr 3+ and Cu 2+ was 

measured at liquid helium temperature to investigate magnetic properties of CuCr 2O 4. 

Temperature dependence of the Cr NMR frequency shows that there exist initial energy 

gap in the dispersion relation of the spin wave. This energy gap is larger than that of the 

Cu ion, implying that spin-orbit coupling of the Cr ion is stronger than that of the Cu 

ion. This is consistent with theory that predicts orbital order for the Cu ion in CuCr 2O 4. 

The canting angle of the Cr 3+ spin was estimated to be 80° by external magnetic field 

dependence of the Cr NMR frequency. Also the line width of the Cr NMR spectrum 

was measured in 7T external magnetic field. The broadening of the spectrum is induced 

by the anisotropy field. The broadening of the Cu NMR spectrum is larger than that of 

the Cr NMR spectrum, implying that orbital ordering, rather than anisotropy field, is 

the main reason of the Cu NMR spectrum broadening. 




PH19 


Magnetic frustration effects in the new colossal magnetoresistance 

oxide NaCr 2O 4 

Hikaru Takeda 1 *, Yasuhiro Shimizu 1 , Masayuki Itoh 1 , Hiroya Sakurai 2 and Eiji 

Takayama- Muromachi 2 

1 Department of Physics, Graduate School of Science, Nagoya University, Japan 


In itinerant electron systems on a geometrically frustrated lattice, the magnetic frustration is 

considered to play a crucial role for their transport properties as seen in LiV 2O 4 which shows the 

heavy fermion-like behavior [1]. Recently, a new chromium oxide NaCr 2O 4 with geometrically 

frustrated double chains was reported to show the unconventional colossal magnetoresistance 

(CMR) effect [2]. Unlike the conventional CMR materials represented by the ferromagnetic 

manganites, NaCr 2O 4 is an antiferromagnet with the Neel temperature TN = 125 K. The origin 

of the CMR effect in NaCr 2O 4 is expected to be closely related to the unconventional spin 

structure generated by the magnetic frustration. In this study, we have performed 23Na NMR 

measurements on NaCr 2O 4 to investigate the spin structure in the antiferromagnetic phase and 

the magnetic correlations. We found the presence of a ferromagnetic interaction, which competes 

with an antiferromagnetic one, from the temperature dependence of the nuclear spin-lattice 

relaxation rate 1/T1. Below TN, 23Na NMR spectra, which change with increasing the external 

magnetic field, cannot be explained by a conventional spin structure. The CMR effect may be 

related to the instability of the spin structure in the external field due to the magnetic frustration. 

[1]S. Kondo, et al., PRL 78, 3729 (1997). [2] H. Sakurai, et al., (unpublished). 

PH20 

Site-dependent metal-insulator transition and orbital order in quasione-dimensional 

V6O13 Satoshi Aoyama 1 , Yasuhiro Shimizu 1 , Masayuki Itoh 2 * and Yutaka Ueda 3 

1 

Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, 

Chikusa-ku, Nagoya, Japan 

2 

Department of Physics, Graduate School of Science, Nagoya University, Japan 

3 

Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 

Japan 

Vanadates are prototypes of metal-insulator transitions with orbital degrees of freedom. 

In a quasi-one-dimensional compound V 6O 13, the mixed valence gives non-uniform 

spin-charge distributions on inequivalent V sites even for the metallic state. Our 

sophisticated 51V NMR measurements using a single crystal distinguished the sitedependent 

orbital order and the local spin susceptibilities on two inequivalent chains. 

One chain behaves as a metallic one with the moderately depressed susceptibility, 

whereas another behaves as an insulating one with the magnetically active local 

moment. The result arises from the site dependent electron correlation, giving the 

net duality in the conducting and magnetic properties. A metal-insulator transition 

occurring at -150 K accompanies with dramatic changes in the charge and orbital 

ordering textures, as we observed in the 51V nuclear quadrupole splitting anisotropy. 

Such ordering separates the metallic chain into magnetic and nonmagnetic sites, giving 

a complex antiferromagnetic spin structure below -50 K. 

PH21 

Synthesis and characterization of CoMn 2O 4 nanopowders by a reverse 

Micelle processing 

Hojung Kim and Dong Sik Bae* 

Department of Convergence Materials Science and Engineering, Changwon National 

Univ., Korea 

CoMn 2O 4 nanoparticles was synthesized by reverse micelle processing the mixed 

precursor (consisting of Co(NO 3) 3 and MnCl 2•4H 2O). The CoMn 2O 4 was prepared 

by mixing the aqueous solution at a molar ratio of Co : Mn = 1 : 2. The synthesized 

powders were calcined at 600°C for 2h. The average size and distribution of 

synthesized powders were in the range of 10-20nm and narrow, respectively. The 

average size of the synthesized powders increased with increasing water to surfactant 

molar ratio. The XRD diffraction patterns show that the phase of CoMn 2O 4 was spinel 

(JCPDS no.77-0471). The synthesized and calcined powders were characterized by 

thermo gravimetry- differential scanning calorimeter (TG-DSC), X-ray diffraction 

analysis (XRD) and transmission electron microscopy (TEM). The magnetic property 

of the powder was measured by Vibrating Sample Magneto-meter (VSM) at 298K. 

The effect of synthesis parameter, such as the molar ratio of water to surfactant, is 

discussed. 


PH22 

The patterning with a circular magnet array, its observation and 

domain switching in ferromagnetic ZnCoO:H 

Won-kyung Kim, Seunghun Lee, Sang-uk Cho, Yong-chan Cho, Hideomi Koinuma and Se-young Jeong* 

Cogno-Mechatronics Engineering, Pusan National University, Korea 

Today’s spintronic technologies are considered to be the most progressive solution for overcoming the typical 

semiconductor electronics. Many researchers have extensively studied the effect of size, shape, structure 

on single-domain magnet and its wall motion with permanent magnetic metal for high-density magnetic 

memory and logic devices[1,2]. However, the fact that permanent magnetic metals could not reprogram 

after the first design for logic devices is still remaining as an important issue. Thus, hydrogen-mediated 

Co-doped ZnO(ZnCoO:H) having reversible room-temperature ferromagnetism has been considered as 

a strong candidate material for spintronic devices[3]. In this study, we observed domain switching in a 

ZnCoO:H in real-space and simulate it using object-oriented micromagnetic framework(OOMMF). ZnCoO 

circular patterns are fabricated by rf-sputtering and various lithography processes, and hydrogen is injected 

by plasma and hot isostatic pressing(HIP) methods. The reversible magnetic single-domain behavior is 

activated and deactivated by hydrogen manipulation, which are investigated with superconducting quantum 

interference device(SQUID) and magnetic force microscopy(MFM) measurements, and the results are 

compared with the OOMMF simulation. This reversible room-temperature magnetic switching of the oxide 

materials could greatly contribute to the development of reprogrammable spin logic devices. 

[1] S. Y. Chou, Proc. IEEE 85, 652 (1997); G. A. Prinz, Science 282, 1660 (1998) [2] E. R. Lewis et al., Nat. Mater. 9, 

980 (2010); J.-C.Lee et al,. Phys. Rev. Lett. 107, 067201 (2011) [3] H. J. Lee et al., Appl. Phys. Lett. 88, 062504 (2006); 

S. Lee et al., Appl. Phys. Lett. 94, 212507 (2009); Y. C. Cho et al., Appl. Phys. Lett. 95, 172514 (2009); S. J. Kim et al., 

Phys. Rrev. B 81, 212408 (2010); S. Lee et al., J. Appl. Phys. (accepted); J. M. Shin et al., Phys. Rev. Lett. (submitted) 

PH23 

Orbitally induced molecule formations in itinerant triangular 

vanadates 

Yasuhiro Shimizu 1 *, Ken-ichiro Matsudaira 1 , Masayuki Itoh 1 and Yutaka Ueda 2 



An intriguing route that eliminates the geometrical frustration is the orbitally-induced 

symmetry breaking usually described by the Kugel-Khomskii model. In itinerant 

systems, however, the model for localized electrons may not be guaranteed, and the 

degenerated d orbitals can be partially occupied. We show that the orbital occupation 

continuously changes into a valence-bond-solid ground state in an itinerant vanadate 

BaV 10O 15 with a triangular lattice, based on the orbital-resolved nuclear magnetic 

resonance technique. Owing to the odd number of d electrons, i. e., eleven electrons 

for a five-V unit, all the V sites cannot form the valence bonds. Instead, two of the five 

V sites, sharing five electrons, remain magnetic with the ferro-orbital ordering [1]. In 

clear contrast, no commensurate spin order and orbital order are stabilized in SrV 10O 15. 

The result suggests fractional and incommensurate spin-orbital orders that cannot fully 

remove the geometrical frustration. 

[1]Y. Shimizu, K. Matsudaira, M. Itoh, T. Kajita, and T. Katsufuji, Phys. Rev. B. 84, 064421 (2011). 

PI01 

Investigation of magnetocaloric effect in La 0.45Pr 0.25Ca 0.3MnO 3 by 

differential scanning calorimetry and thermal analysis 

Aparnadevi M, Sujit Kumar Barik and Ramanathan Mahendiran* 

Department of Physics, National university of Singapore, Singapore 

We investigated magnetocaloric effect in La 0.45Pr 0.25Ca 0.3MnO 3 by direct (changes in 

temperature and latent heat) and indirect methods (magnetization isotherms). This 

compound undergoes a first-order paramagnetic to ferromagnetic transition with Tc 

= 200 K upon cooling. The paramagnetic phase becomes unstable and it transforms 

into a ferromagnetic phase under the application of magnetic field, which results in 

field-induced metamagnetic transition (FIMT). The FIMT is accompanied by release 

of latent heat and change in temperature of the sample as evidenced from differential 

scanning calorimetry and thermal analysis experiments. A large magnetic entropy 

change of ΔSm = -7.3 Jkg-1K-1 at Tc = 212.5 K and refrigeration capacity of 228 J/ 

kg are observed for a field change of ΔH = 5 T. It is suggested that the nanometer 

sized ferromagnetic clusters co-exist with short-range charge-ordered clusters in the 

paramagnetic state, resulting in a large value of ΔSm above the Tc.

PI02 

Specific heat and magnetic properties of spinel compound FeV 2O 4 

Shogo Kawaguchi*, Yoshiki Kubota and Hiroki Ishibashi 

Department of Physical Science, Graduate School of Science, Osaka Prefecture 


The spinel compound FeV 2O 4 has the orbital degrees of freedom at both eg (Fe 2+ ) and 

t2g (V 3+ ) orbitals. This compound shows successive structural phase transitions at 

about 140 K, 110 K accompanied by ferrimagnetic ordering, 70 K and 35 K. However, 

the details of the phase transitions below 110 K are still not understood. In order to 

clarify the origin of these phase transitions, we measured magnetization and specific 

heat capacity for polycrystalline and single crystal of FeV 2O 4. We first observed three 

anomalies at 140 K, 109 K and 68 K with decreasing temperature in the specific heat 

measurements using the polycrystalline sample. The λ-type anomaly at 109 K indicates 

the second order phase transition, which is related to the ferrimagnetic ordering. 

Moreover, the anomaly at 68 K has a sharp peak, which conforms to the anomaly 

on the temperature dependence of magnetic susceptibility. The electronic specific 

coefficient γ =1.8 mJ/molK2 of FeV 2O 4 is smaller than that of of MnV 2O 4 (γ = 12 mJ/ 

molK2)[2] because the Jahn-Teller effect of Fe 2+ for FeV 2O 4 may weaken the electronelectron 

interactions. The details of the measurements using single crystal and the 

correlation between the crystal and the magnetic structures are also discussed. 

[1] T. Katsufuji et al., J. Phys. Soc. Jpn. 77 (2008) 053708 [2] K. M. Whun et al., Phys. Rev. B 83 

(2011) 024403 

PI03 

The crossover to checkerboard charge order: Magnetic excitations of 

charge-stripe ordered of La 2-xSr xNiO 4. 

Paul G Freeman 1 , A. T. Boothroyd 2 , D. Prabhakaran 2 , K. Hradil 3 , R. A. Mole 4 and S. R. Giblin 5 

1 Helmholtz-Zentrum Berlin, Germany; EPFL, Lausanne, Switzerland; ILL, Grenoble, France 

2 Department of Physics, Oxford University, United Kingdom 

3 Technische Universitat Wien, Austria; Institut fur Physikalische Chemie, Universitat Gottingen, Germany 

4 Bragg Institute, ANSTO, Australia; FRM II, Germany 

5 ISIS Facility, Rutherford Appleton Laboratory, United Kingdom 

Are stripes ubiquitous to the cuprates, and what is the role of stripes in high temperature superconductivity, are 

two questions that have been intensively debated since the discovery of charge stripe order in the cuprates[1]. 

From studying the magnetism of charge-stripe ordered La 2-xSr xNiO 4 (LSNO) the magnetic interactions of a 

charge-stripe ordered phase have been quantitatively described[2], although our knowledge is incomplete[3]. 

For x = 1/2 the ground state order of LSNO is part stripe and part checkerboard like in character, with both 

the magnetic excitations from the ordered moments and charge stripe electrons showing dramatic differences 

compared to lower doping levels [2,3]. Variations of the charge-stripe periodicity, discommensurations, create 

additional magnetic excitations from the ordered moments in the x = 1/2 compared to damping the excitations 

at x ~ 1/3. While the magnetic excitations from the charge stripe electrons have a different wavevector 

centring in the x = 1/2 [3,4]. We report a neutron scattering study of the magnetic excitations in LSNO x = 0.4 

and 0.45. Between these two doping levels the magnetic excitations show a dramatic crossover in character. 

We discuss this crossover behaviour with regards to charge-stripe materials with larger charge stripe spacing. 

[1] M. Tranquada, et. al., Nature (London) 375, 561 (1995). [2] H. Woo et. al. Phys. Rev. B 72, 064437 (2005). [3] 

P. G. Freeman, et. al. Phys. Rev. B 71, 174412 (2005). [4] A. T. Boothroyd , et. el., Phys. Rev. Lett. 91 257201 (2005). 

PI04 

Magnetic properties of low-dimensional α and γ CoV 2O 6 

Marc Lenertz*, Jonathan Alaria, Daniel Stoeffler, Silviu Colis and Aziz Dinia 

DCMI, Institut de Physique et Chimie des Materiaux de Strasbourg, CNRS - 

Universite de Strasbourg, France 

CoV 2O 6 is a low dimensional oxide existing in two allotropic phases, generally 

called α and γ, and showing monoclinic and triclinic structures, respectively. We 

synthesized this oxide by solid state reaction and performed neutrons diffraction and 

magnetic measurements in order to understand the magnetic behavior in correlation 

with the low dimensional structure. The magnetic properties were supported by ab 

initio calculations. Both phases are constituted of parallel 1D Co chains organized in 

planes that are separated by vanadium oxide thin layers and are antiferromagnetic in 

the ground state. The magnetization curves recorded at 5 K show a stepped variation 

with sharp field-induced magnetic transitions and a magnetization plateau at one-third 

of the saturation magnetization. In α-CoV 2O 6, additional steps are evidenced at 1.8 K. 

The magnetic moment per Co ion is larger in the α phase (4.5 μB) than in the γ phase 

(3 μB), although Co has the same octahedral environment in both cases. Ab initio 

calculations show that α-CoV 2O 6 is an antiferromagnetic semiconductor with a gap 

of 1.1 eV in which the magnetic moment is essentially carried by Co and can reach a 

maximum value of about 4.2 μB for a meta-stable solution. 

M. Lenertz, J. Alaria, D. Stoeffler, S Colis and A. Dinia, J. Phys. Chem. C, 2011, 115, 17190-17196 

PI05 

PI06 

PI07 


Structural and magnetic properties of the parent compound T'- 

La 2CuO 4 of electron-doped cuprates 

Gwendolyne Pascua 1 , Hubertus Luetkens 1 , Marco Guenther 2 , Roland Hord 3 , Lukas 

Keller 4 , Vladimir Pomjakushin 4 , Andreas Suter 1 , Hemke Maeter 2 , Alexander Buckow 5 , 

Barbara Albert 3 , Hans-henning Klauss 2 and Lambert Alff 5 

1 Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland 

2 Institut fuer Festkoerperphysik, TU Dresden, DE-01069 Dresden, Germany 

3 Eduard-Zintl-Institute of Inorganic and Physical Chemistry, TU Darmstadt, Petersenstr. 18, DE- 

64287, Darmstadt, Germany 

4 Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland 

5 Institute of Materials Science, TU Darmstadt, Petersenstr. 23, DE-64287 Darmstadt, Germany 

Recently, we found that the newly synthesized metastable T'-La 2CuO 4 exhibits much lower Neel temperature (TN) 

and increased magnetic fluctuations compared to other mother compounds of electron-doped superconductors like 

Nd 2CuO 4 or Pr 2CuO 4. Muon spin rotation (μSR) reveals a gradual slowing down of dynamic magnetic fluctuations 

below TN1=220K and static magnetic order below TN2=115K in contrast to T-La 2CuO 4 where TN2=300K. In 

comparison to our T’-La 2CuO 4, measurements were done on T’-Pr 2CuO 4 to study the effect of a magnetic rare 

earth ion on the magnetism. Zero-Field μSR on T’-Pr 2CuO 4 shows oscillations at high temperatures up to 220K in 

sharp contrast to the predominantly dynamic character of the depolarization in T’-La 2CuO 4 in the same temperature 

range. This clearly demonstrates that the magnetism of T’-La 2CuO 4 is much more 2-dimensional than in T’-Pr 2CuO 4. 

Interestingly, there is also an abrupt change of the internal field distribution at TN3=40K for both the T’-La 2CuO 4 

and the T’-Pr 2CuO 4 compounds consistent with a reorganization of the magnetic structure at this temperature. La- 

NMR results for the T’-La 2CuO 4 also display anomalies at the abovementioned characteristic temperatures. In 

addition, μSR and neutron scattering results on T’-Pr 2CuO 4 indicate a similar behaviour previously observed for 

Nd 2CuO 4 pointing to, up-to-now undetected spin reorientation transitions. 

[1] R. Hord, H. Luetkens, et al., Phys. Rev. B 82, 180508(R) (2010). [2] G. M. Luke et al., Phys. Rev. B 42, 7981 (1990). 

[3] I.W. Sumarlin, et al., Phys. Rev. B 51, 5824 (1990). [4] V.P. Plakhty et al., Phys. Lett. A 250, 201 (1998). [5] R. 

Sachidanandam et. al., Phys. Rev. B 56, 260 (1997). [6] S. Katano, et al., Physica C 215, 92 (1993). 

Microscopic magnetic nature of the quasi-one-dimensional 

antiferromagnet BaCo 2V 2O 8 

Martin Mansson 1 *, Krunoslav Prsa 1 , Jun Sugiyama 2 , Hiroshi Nozaki 2 , Alex Amato 3 , 

Shojiro Kimura 4 , Kumiko Omura 5 , Masayuki Hagiwara 5 and Andrey Zheludev 1 

1 Lab. for Solid State Physics, ETH Zurich, Switzerland 

2 Toyota Central Research and Development Labs. Inc., Japan 

3 LMU, Paul Scherrer Institut, Switzerland 



BaCo 2V 2O 8, belongs to a wide group of quasi-1D antiferromagnets (AF). The Q1D compounds display a 

variety of fascinating ground states governed by the strong spin-spin coupling along the 1D direction and a 

much weaker coupling along other directions. BaCo 2V 2O 8 display a long-range AF order below TN=5 K 

and possibly short-range order all the way up to 30 K. Further, a novel type of field induced magnetic order 

has been found for T3.9 T [1,2]. It was determined to be an incommensurate spin structure 

caused by quantum fluctuations, fitting well to theoretical predictions for a so-called Tomonaga-Luttinger 

liquid (TLL). To the best of our knowledge, we present here the first μSR investigation of the microscopic 

magnetic nature of single crystalline BaCo 2V 2O 8 samples. Our data reveal several clear muon frequencies 

below TN indicating the onset of a long-range order. Above 5 K, the μSR spectra are well fitted to a simple 

power-exponential relaxing function. The temperature dependence of the relaxation-rate as well as the 

power display a clear anomaly around T=40 K, indicating the onset of short-range 1D correllations. Finally 

we also present initial and intriguing field dependent data. 

[1] S. Kimura et al. PRL 100, 057202 (2008) [2] S. Kimura et al. PRL 101, 207201 (2008) Funding 

Source: Swiss National Science Foundation (Project 6, NCCR MaNEP) and Toyota CRDL. 

Detection of orbital wave in YVO 3 using inelastic neutron scattering 

Daichi Kawana 1 , Youichi Murakami 1 , Tetsuya Yokoo 2 , Shinichi Itoh 2 , Andrei T Savici 3 , 

Garrett E Granroth 3 , Kazuhiko Ikeuchi 4 , Hironori Nakao 1 , Kazuaki Iwasa 5 , Ryuichiro 

Fukuta 6 , Shigeki Miyasaka 6 , Setsuko Tajima 6 , Sumio Ishihara 5 and Yoshinori Tokura 7 

1 Condensed Matter Research Center, Institute of Materials Structure Science, KEK, Japan 

2 Neutron Science Division, Institute of Materials Structure Science, KEK, Japan 

3 Neutron Scattering Sciences Division, Oak Ridge National Laboratory, USA 

4 Comprehensive Research Organization for Science and Society, Japan 

5 Department of Physics, Tohoku University, Japan 


7 Department of Applied Physics, University of Tokyo, Japan 

We focus on an orbital excitation in YVO 3, which shows the complex magnetic and orbital orderings in 

the low temperatures [1]. In the phase where the G-type orbital order accompanied with the C-type spin 

order (G-OO/C-SO) appears, the existence of the large orbital fluctuation is suggested [2]. Additionally, a 

large dispersive orbital-wave along the c-axis, due to the strong one-dimensional spin-orbital correlation, 

is calculated [3]. In consideration of the neutron scattering cross-section obtained from the correlation 

function for the orbital angular moment, we have attempted to detect the orbital excitation using inelastic 

neutron scattering spectrometers. We observed a magnetic excitation up to 35 meV. This energy range is 

higher than that reported previously [3]. On the other hand, weak excitations are observed in the range of 

40-70 meV. In this Presentation, we discuss whether these are originated from orbital excitation or not. 

[1] S. Miyasaka et al., Phys. Rev. B 73, 224436 (2006). [2] C. Ulrich et al., Phys. Rev. Lett. 91, 

257202 (2003). [3] S. Ishihara, Phys. Rev. B 69, 075118 (2004). 




PI08 


Orbital occupation and magnetism of tetrahedrally coordinated Fe in 

CaBaFe 4O 7 

Nils Hollmann 1 , Martin Valldor 2 , Hua Wu 2 , Zhiwei Hu 1 , Navid Qureshi 2 , Thomas 

Willers 2 , Yi-ying Chin 3 , Julio Cezar 4 , Arata Tanaka 5 , Nicholas Brookes 4 and Liu Hao 

Tjeng 3 

1 Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany 

2 II. Institute of Physics, University of Cologne, Germany 

3 Max-Planck-Institute for Chemical Physics of Solids, Germany 

4 European Synchrotron Radiation Facility, Grenoble, France 

5 Department of Quantum Matter, ADSM, Hiroshima University, Japan 

CaBaFe 4O 7 is a new mixed-valent transition metal oxide from the class of 

Swedenborgites [1,2] having both Fe 2+ and Fe 3+ ions in tetrahedral coordination situated 

in a Kagome lattice. This class of materials could be an interesting starting point to study 

orbital physics in tetrahedral coordination. Here we characterize its magnetic properties 

by magnetization measurements and investigate its local electronic structure using 

soft x-ray absorption spectroscopy at the Fe L2,3 edges, in combination with multiplet 

cluster simulations and band structure calculations [3]. We found that the Fe 2+ ion in the 

unusual tetrahedral coordination is Jahn-Teller active having a minority-spin electron 

with an x2-y2 character. We deduce that there is an appreciable orbital moment caused 

by multiplet interactions, thereby explaining the observed magnetic anisotropy. 

[1] B. Raveau et al., Chem. Mat. 20, 6295 (2008) [2] B. Raveau et al., Z. Anorg. Allg. Chem. 635, 

1869 (2009) [3] N. Hollmann et al., Phys. Rev. B 83, 180405 (2011) 

PI09 

Search for topological spin order in the multiferroic insulator 

Cu2OSeO3 M. Wagner 1 , T. Adams 1 , A. Chacon 2 , G. Brandl 2 , H. Berger 3 , P. Lemmens 4 and C. 

Pfleiderer 1 

1 

Physik-Department, Technische Universitaet Muenchen, D-85748 Garching, 

Germany 

2 

Physik-Department and Forschungsneutronenquelle Heinz-Maier Leibniz, TU 

Muenchen, D-85748 Garching, Germany 

3 

Ecole Polytechnique Federale Lausanne, CH-1015 Lausanne, Switzerland 

4 

Institut fuer Physik, Technische Universitaet Braunschweig, Germany 

We report a comprehensive study of the magnetic properties of single crystals of the 

multiferroic insulator Cu 2OSeO 3. Our study was motivated by the recent discovery of a 

skyrmion lattice phase in the B 20 transition metal Si and Ge transition metal compounds 

[1], which are isostructural siblings of Cu 2OSeO 3. For our study large high-quality single 

crystals were grown by vapour transport. The magnetisation, ac susceptibility and specific 

heat were measured down to 2K under magnetic fields up to 9T. The magnetic properties 

were studied with small angle neutron scattering. We find a paramagnetic to helimagnetic 

transition at T_c - 58K. The magnetic phase diagram of Cu 2OSeO 3 shares remarkable 

similarities with the B 20 transition metal silicides, including the existence of a small phase 

pocket below T_c. The putative evidence for topological spin order is compared with the 

evidence for a skyrmion lattice in B 20 transition metal Si and Ge compounds. 

[1] S. Muehlbauer et al., Science 323, 915 (2009). 

PI10 

Studies of neutron scattering and bulk properties of honeycomb lattice 

Li2MnO3 Sanghyun Lee 1 , Sungil Choi 1 , Jiyeon Kim 1 , Choongjae Won 2 , Seongsu Lee 3 , Shin-ae 

Kim 3 , Namjung Hur 2 and Je-geun Park 4 * 

1 

Center for Strongly Correlated Materials Research, Seoul National University, Seoul 

151-742, Korea, Korea 

2 

Department of Physics, Inha University, Incheon 402-751, Korea, Korea 

3 

Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305- 

353, Korea, Korea 

4 

Department of Physics & Astronomy, Seoul National University, Seoul 151-742, 

Korea, Korea 

Li 2XO 3 with transition metal ions occupying the X position forms an interesting 

honeycomb lattice. Among Li 2XO 3, Li 2RuO 3 was recently found to have an unusual 

structural phase transition involving probably Ru dimerization. For example, it 

was reported that the crystal structure changes from P21/m to C2/m near 540 K, 

accompanied by a concomitant metal-insulator transition and an abrupt change in 

the magnetic susceptibility. Li 2MnO 3 is another example having the C2/m crystal 

structure with the honeycomb lattice. In order to investigate the magnetic properties of 

Li 2MnO 3, we have successfully grown single crystal Li 2MnO 3 by using a flux method. 

Using these single crystals, we have carried out both bulk measurements and neutron 

diffraction studies with high resolution powder diffractometer (HRPD) and single 

crystal diffractometer (FCD) at HANARO, Korea. We also measured the magnetization 

and heat capacity of the single crystals. 


PI11 

Magnetic and calorimetric properties of Mn 2GeO 4 single crystals 

Natalia Mihashenok*, Nikita Volkov, Klara Sablina, Alexander Balaev, Maxim 

Molokeev, Sergei Popkov and Dmitriy Velikanov 

L.V. Kirensky Institute of Physics SB RAS, Russia 

Within the framework of our research of manganese oxides the single crystals 

Mn 2GeO 4 have been grown by the flux method using the original technique [1]. The 

crystal structure, an isomorph of olivine, was determined on single crystal by X-ray 

diffraction method: cell parameters, a=10.7401 A , b=6.3116 A, c=5.0766 A, and 

the space group Pnma. Magnetic measurements were performed in the temperature 

range from 2 to 300 K and in magnetic fields up to 50 kOe with the exact orientation 

of the applied magnetic field relative to the crystallographic directions of the crystal. 

There are three sharp magnetic phase transition at T1=47 K, T2=17.5 K and T3=5.5 

K, with phase transition at T2 depended on applied magnetic field. Also the specific 

heat measurements of single crystals were carried out. The heat capacity of Mn 2GeO 4 

exhibits three sharp maxima, which exactly correlate with the magnetic phase 

transition. 

[1] Sapronova N.V., Volkov N.V., Sablina K.A., Petrakovskii G.A., Bayukov O.A., Vorotynov A. M., 

Velikanov D.N., Bovina A.F., Vasilyev A.D., Bondarenko G.V. Phys. Stat. Sol. B., 246 (2009) 206 

PI12 

Effect of doping on the magnetic structure of YMn1-xMxO3 (M = Ga, Ti, 

x ≤ 0.1) 

Neetika Sharma 1 , Poonam Kumari 2 , A. Das 1 * and G. Ravi Kumar 3 

1 

Solid State Physics Division, Bhabha Atomic Research Centre Mumbai, India 

2 

UM - DAE Centre for Excellence in Basic Sciences University of Mumbai, Mumbai, 

India 

3 

Technical Physics Division, Bhabha Atomic Research Centre Mumbai, India 

The effect of doping at the Mn site of multiferroic manganites, YMn 1-xM xO 3 (M = Ga, Ti, x 

≤ 0.1) have been studied by neutron powder diffraction and magnetic measurements. These 

compounds have been prepared by solid state synthesis techniques. All the compounds studied 

are isostructural and crystallizes with hexagonal structure in P63cm space group. We find that 

both Ga 3+ (d10) and Ti 4+ (d0) doping leads to significant reduction in the magnetic transition 

temperature (TN) while they influence the magnetic structure of YMnO 3 differently. The 

magnetic structure of YMnO 3 is described by the irreducible representation Γ1 (or Γ3 ) with 

moment on Mn~3μB at 5K, in agreement with previously reported values on this compound 

[1]. We find that the representation remains the same on doping with Ga in YMnO 3 albeit with 

a decrease in the value of the moment to 2.5μB at 6K. However, the irreducible representation 

changes on doping with Ti, and this modified structure is given by the basis vectors of the 

irreducible representation Γ2 with moment 2.1μB at 6K. The geometrical frustration parameter, 

f = θp/Tn, ~ 7 and reduces with doping. These observations are different from the earlier 

reported doping studies carried out in this compound [2]. 

[1]. J.A. Alonso et al. Phys. Rev. B 62 9498 (2000) [2] J. Park et al., Phys. Rev. B 79 064417 (2009) 

PI13 

Neutron diffraction and magnetic properties of Ba 2Co 2Fe 12O 22: Co 2Y 

Chan Hyuk Rhee 1 , Jung Tae Lim 1 , Sung Wook Yoon 1 , Kwang Lae Cho 1 , Sung Baek 

Kim 2 and Chul Sung Kim 1 * 

1 Department of Physics, Kookmin University, Korea 

2 Advancement for College Education Center, Konyang University, Korea 

Y-type hexa-ferrites with non-collinear magnetic structure have been studied for 

magnetoelectric effect, showing induced electric polarization under external magnetic 

field. The helical magnetic structure of these ferrites depends on the temperature and 

magnetic field [1]. Here, polycrystalline Y-type barium cobalt ferrite (Ba 2Co 2Fe 12O 22; 

Co 2Y) was synthesized by conventional ceramic method in O 2 gas atmosphere to 

reduce the oxygen defect. The temperature and magnetic field dependence of magnetic 

structure was investigated by neutron diffraction and vibration sample magnetometer. 

At temperature below TN = 615 K, the crystal structure of Co 2Y was determined to 

be rhombohedral with the space group R-3m. It showed soft ferrimagnetic behavior 

with Hc of 145 Oe at 297 K. Most of super-lattice peaks from spin structure decreased 

with increasing temperature. However, the peak at 21.1o increased with increasing 

temperature at temperatures above 205 K. In addition, the slope of zero-field cooled 

magnetization under low field of 0.01 T changed at 205 K. This magnetic structure 

transition temperature of Co 2Y is higher than that of Ba 2Mg 2Fe 12O 22 [1] due to the 

presence of cobalt ion with strong magnetic anisotropy. 

[1] S. Ishiwata, Y. Taguchi, H. Murakawa, Y. Onose, and Y. Tokura, Science 319, 1643 (2008).

PI-14 

Mössbauer studies of olivine Fe 1-yMn yPO 4 

Woo Jun Kwon, In Kyu Lee, Hee Seung Kim, In-bo Shim and Chul Sung Kim* 

Department of Physics, Kookmin University, Korea 

The olivine structured Fe 1-yMn yPO 4 (y = 0.1, 0.3), a possible cathode material for 

lithium ion secondary battery, have been studied by x-ray diffraction and Mössbauer 

spectroscopy. These Fe 1-yMn yPO 4 samples were prepared by chemical deintercalation 

lithium from the LiFe 1-yMn yPO 4. The crystal structures of the Fe 1-yMn yPO 4 samples 

were determined to be orthorhombic (space group Pnma) at 295 K by Rietveld 

refinement method. The lattice constants of the Fe 1-yMn yPO 4 samples increased from 

a0 = 9.833 Å, b0 = 5.811 Å and c0 = 4.786 Å for y = 0.1 to a0 = 9.979 Å, b0 = 5.895 

Å and c0 = 4.799 Å for y = 0.3 with the increasing Mn concentration. From the 

Mössbauer spectra at 295 K, the electric quadrupole splitting (ΔEQ) and isomer shift 

(δ) values of the Fe1-yMnyPO4 were determined to be ΔEQ = 1.50 mm/s, δ = 0.31 

mm/s for y = 0.1 and ΔEQ = 1.35 mm/s, δ = 0.31 mm/s for y = 0.3. The decrease in 

ΔEQ of Fe 1-yMn yPO 4 samples can be explained by the exchange interaction due to the 

asymmetry in FeO 6 octahedral sites depending on the Mn concentrations. 

[1] B. C. Melot, G. Rousse, J.-N. Chotard, M. Ati, J. Rodriguez-Carvajal, M. C. Kemei, and J.-M. 

Tarascon, Chem. Mater. 23, 2922 (2011). [2] W. Kim, C. H. Rhee, H. J. Kim, S. J. Moon, and C. S. 

Kim, Appl. Phys. Lett. 96, 242505 (2010). 

PI15 

Three- dimensional electronic structure of Na0.85CoO2 Y. Sassa 1 *, M. Mansson 1 , B. M. Wojek 2 , J. Chang 3 , M. Kobayashi 4 , J. Kanter 1 , V. 

Strocov 4 , K. Mattenberger 1 and B. Batlogg 1 

1 

Laboratory of Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland 

2 

Materials Physics, Royal Institute of Technology KTH, S-16440 Kista, Sweden 

3 

Laboratory for synchrotron and neutron spectroscopy, Paul Scherrer Institute, CH- 

5234 Villigen PSI, Switzerland 

4 

Swiss Light Source, Paul Scherrer Institute, CH-5234 Villigen PSI, Switzerland 

PI16 

WITHDRAWN 

Formation of stoichiometric of FeO synthesized under high pressure 

Yasushi Kanke 1 , Takuro Yoshikawa 2 , Hideto Yanagihara 2 , Eiji Kita 2 , Yorihiko 

Tsunoda 3 , Kiiti Siratori 2 and Kay Kohn 3 

1 National Institute of Materials Science, Japan 

2 Institute of Applied Physics, University of Tsukuba, Japan 

3 School of Science and Engineering, Waseda University, Japan 

FeO has the simplest NaCl crystalline structure and one electron exists in the 

degenerated dε orbitals due to the regular octahedral ligands. Even such simple 

structure, the partial quenching of the orbital angular momentum (S = 2 and L = 1) 

bring the electronic structure complex.[1] Difficulty in the sample preparation, only the 

samples Fe XO with X ≤ 0.96 have been obtained, makes the experimental investigation 

of FeO hard. We have prepared the stoichiometric FeO with the high pressure synthesis 

technique.[2] The starting material of the mixture of α-Fe and Fe 2O 3 powder was 

sealed in a Pt capsule and was heated up to 1000 °C and 1200 °C under 5.5GPa for 1 

hour. The residual ferromagnetic parts were estimated to be less than 0.69 at%. Higher 

reaction temperature may bring lower concentration of ferromagnetic components. 

From Mossbauer study, it is found that the Koch-Cohen cluster does exist especially 

when the reaction temperature is high. We present the influence of post annealing with 

various conditions for the improvement of degree of stoichiometry. 

[1] J. Kanamori: Prog. Theo. Phys. 17, 177 (1957) [2] T. Katsura, B. Iwasaki, S. Kimura, S. 

Akimoto : J. Chem. Phys. 47, 4559 (1967) 

PI17 

PI18 

PI19 


Charge and spin ordering in Sr 4Fe 4O 11 system 

Qiang Liu 1,2,3 , Gwendolyne Pascua 4 , Alexander Komarek 3 , Zhiwei Hu 3 , Nils Hollmann 3 , Olivier 

Toulemonde 2 , Hubertus Luetkens 4 , Gwilherm Nenert 5 , Alain Wattiaux 2 , Liu Hao Tjeng 3 

1 II. Physikalisches Institut, Universität zu Köln, Germany 

2 Institut de Chimie de la Matière Condensée de Bordeaux, France 

3 Max-Planck-Institut für chemische Physik fester Stoffe, Dresden, Germany 

4 Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute,CH-5232 Villigen PSI, Switzerland. 

5 Institut Laue-Langevin, 38042 Grenoble Cedex 9, France 

Ordering and disordering of charge, spin, lattice and orbital degrees of freedom play an important 

role in the physics of strongly correlated electron systems. In the mixed valence (Fe 3+ /Fe 4+ ) 

compound Sr 4Fe 4O 11, the spin and charge ordering have recently generated a debate arising 

from its two crystallographic (pyramidal and octahedral) sites and the distribution of Fe 3+ 

and Fe 4+ species [1-5]. Due to symmetry reasons, either the Fe 4+ sublattice is frustrated while 

Fe 3+ ions order antiferromagnetically or the opposite. We are trying to explore this puzzle by 

X-ray Absorption Spectroscopy, Photoemission Spectroscopy, muSR, Neutron, Synchrontron 

X-ray diffraction and MOssbauer measurement on precisely adjusted oxygen stoichiometric 

polycrystalline samples and single crystals. 

1.J. P. Hodges, S. Short, J. D. Jorgensen, X. Xiong, B. Dabrowski, S. M. Mini, and C. W. Kimball. J. Solid. State. Chem. 

151,190-209 (2000) 2 M Schmidt, M Hofmann and S J Campbell. J. Phys.: Condens.Matter 15, 8691-8701 (2003) 3 

P Adler, A Lebon, V Damljanovic, C Ulrich, C Bernhard, AV Boris, A Maljuk, CT Lin, and B Keimer. Phys. Rev. B 73, 

094451(2006) 4 R. Vidya, P. Ravindran, H. Fjellvag, and A. Kjekshus. Phys. Rev. B 74, 054422 (2006) 5 P.Adler Comment 

Phys. Rev. B 77, 136401 (2008) and R. Vidya Reply Phys. Rev. B 77, 136402 (2008) 

Catalyst structure determination from magnetic properties 

Jorge Hernandez-velasco 1 *, Javier Garcia-garcia 2 and Angel Landa-canovas 1 

1 Energy, ICMM CSIC, Spain 

2 CME UCM, Spain 

SbVO 4 series of compounds could be used as oxidation catalysts of industrial 

interest yielding 20% cheaper acrylonitrile (production 8 million ton/year) by the 

ammoxidation of propane compared to current method based on propylene as 

starting reactant. SbVO 4 structure was just known to be related to tetragonal rutile. 

Nevertheless we have shown that actually there is a non-stoichiometric flexible series 

described as Sb 0.9V 0.9+x□ 0.2-xO 4 (0


PI20 


Theoretical modeling of the magnetic properties and magnetocaloric 

effect in La 0.1Ca 0.9MnO 3 manganite by Monte Carlo study. 

Oksana Pavlukhina*, Vacily Buchelnikov and Vladimir Sokolovskiy 

Chelyabinsk State University, Russia 

Manganites have a special place among various materials which have a magnetocaloric 

effect. This materials, first, allow varying temperature of phase transitions in wide region 

of temperatures, and secondly, they are cheap and ecological. Experimental studies have 

shown that the manganites are also attractive for the application in magnetic refrigeration [1]. 

In this work, using the Heisenberg’s Hamiltonian, we investigated by Monte Carlo method 

magnetic and magnetocaloric properties of La 0.1Ca 0.9MnO 3. In the simulation, magnetic 

Mn 4+ and trivalent Mn 3+ ions are described by classical Heisenberg spins, while oxygen and 

calcium ions are considered as non-magnetic. Mn magnetic ions are distributed on a lattice 

according to the perovskite structure of the manganite. For the modelling lattice samples of 

size L3 with L=15 were used. Around 5x105 Monte Carlo steps per spin were considered 

in order to compute equilibrium averages. Curie temperature obtained during the theoretical 

simulations (TC ~150 K) agrees well with theoretical result for this compound (TC ~150 

K) [2]. The Curie temperature and magnetocaloric effect obtained during the theoretical 

simulations agree well with experimental data. Support by RFBR grants 10-02-96020-r-ural, 

11-02-00601 and Federal Target Program № 14.740.11.1442 (03.11.2011) is acknowledged. 

1 Phan, Manh-Huong. 2007, Review of the magnetocaloric effect in manganite materials, J. Magn. Magn. 

Mater. 308: 325-340. 2 Restrepo-Parra E. 2011, Magnetic phase diagram simulation of La1-xCaxMnO3 system 

by using Monte Carlo, Metropolis algorithm and Heisenberg model, J. Magn. Magn. Mater, 323:1477-1483. 

PI21 

Pressure effects on magnetic ordering transitions of bilayer manganites 

Pr(Sr1-xCax) 2Mn2O7 (x=0,1) by neutron diffraction and muon spin 

rasonance 

Guochu Deng 1 *, Denis Cheptiakov 2 , Ekaterina Pomjakushina 3 and Kazimierz Conder 3 

1 

Bragg Institute, Australian Nuclear Science and Technology Organization, Australia 

2 

Laboratory for Neutron Scattering (LNS), Laboratory for Neutron Scattering, Paul 

Scherrer Institut, Switzerland 

3 

Laboratory for Developments and Methods, Paul Scherrer Institute, Switzerland 

. 

PI22 

Magnetization reversal and chemical pressure effect in the electron 

doped manganite Ca(Mn 1-xSb x)O 3 

Syuya Ohuchi 1 , Michiaki Matsukawa 1 *, Satoru Kobayashi 1 , Shigeki Nimori 2 and 

Ramanathan Suryanarayanan 3 

1 Dep. of Materials Science and Engineering, Iwate University, Japan 


3 Universite Paris-Sud, France 

WITHDRAWN 

In ref.1, we have demonstrated the effect of hydrostatic pressure of magnetic and 

transport properties, and thermal transport properties in the electron doped manganite 

Ca(Mn 1-xSb x)O 3. The substitution of Sb 5+ ion for Mn4+ site of the parent matrix causes 

one-electron doping since the X-ray photoemission spectroscopy of Sb substituted 

CaMnO 3 sample reveals that the valence of Sb ion is 5+. Anomalous magnetization 

reversals are observed at x=0.05 and 0.08 in the field cooled magnetization while the 

application of external pressure induces a suppression of the negative magnetization. 

The effect of chemical pressure on magnetization of Ca(Mn,Sb)O 3 are examined 

through the substitution of Ca ion for Sr with larger ion radius and are compared 

with the effect of external pressure on that of the same compound. We believe that 

the magnetization reversal is not caused by ferrimagnet model but is associated with 

the presence of the Jahn-Teller type orbital lattice coupling between 3d eg electron 

and MnO 6 octahedron, giving stabilization of negative canted spin state through the 

Dzyaloshinsky-Moriya interaction. 

Ref.1, Y.Murano et al., Phys.Rev.B83,054437 (2011). 


PI23 

The effect of cu substitution on the structural, electrical and magnetic 

properties of LaMn 1-xCu xO 3 manganites 

Parviz Kameli*, H. Vaezi, B. Aslibeiki and H. Salamati 

Isfahan University of Technology, Iran 

The hole-doped manganites, La 1-xA xMnO 3 (A = Sr, Ca, Ba or vacancies) with a 

Perovskite structure have attracted considerable attention due to the discovery of the 

phenomenon of colossal magnetoresistance (CMR) and its potential application [1- 

3]. In this study, the effect of Cu substitution on structural, electrical and magnetic 

properties of LaMn 1-xCu xO 3+δ (0≤ x ≤ 0.075) manganites are investigated by XRD, 

electrical resistivity and Ac susceptibility measurements. The XRD refinement 

result indicates that the samples are single phase and the lattice parameters and 

volumes increase by the increase of the Cu doping level. The resistivity measurement 

results show that by increasing Cu doping level, the resistivity decreases and the 

heavily doped samples show metal - insulator transition at low temperatures. The 

paramagneticferromagnetic transition temperature, Tc increases for low level doped 

samples and decreases for heavily doped samples. The analysis of the frequency 

dependent Ac susceptibility measurements by critical slowing down model, indicates 

that the reentrant spin glass (RSG) state exists in x=0.025, 0.05 and 0.075 samples. 

The RSG state is mainly ascribed to the coexistence of ferromagnetic (FM) and 

antiferromagnetic (AFM) phases and increase of disorder in the FM matrix induced by 

the random Cu impurity. 

PI24 

Investigation of the structural and magnetic peroperties of 

La 0.9Sr 0.1MnO 3 nanoparticles 

M. Eshraghi 1 *, M. Roshanmehr 1 , F. Khademi 2 , P. Kameli 2 and H. Salamati 2 

1 Department of Physics, Payame Noor University, Iran 

2 Department of Physics, Isfahan University of Technology, Iran 

In recent years, magnetic nanoparticles have been the subject of intense research not 

only for their fundamental scientific interest such as superparamagnetism, but also 

for their potential applications in magnetic storage media, biosensor devices and 

medical applications, such as targeted drug delivery and hyperthermia [1-3]. In a large 

number of magnetic nanoparticles applications, it is important to know the effects of 

interaction between nanoparticles on physical properties of these systems. In this paper, 

we studied the structural and magnetic properties of La 0.9Sr 0.1MnO 3 nanoparticles. 

Magnetic nanoparticles of La 0.9Sr 0.1MnO 3 manganite with mean particle sizes of 20 

nm were prepared by the Microwave synthesis method. The crystal structure of the 

samples were analyzed, using X-ray diffractometer with Cu-kα ( 0.154 nm) radiation. 

The morphology of the samples was characterized by a scanning electron microscope 

(FESEM). Magnetic dynamics of the samples was studied by the measurement of ac 

magnetic susceptibility versus temperature and frequency. The XRD pattern along 

with Rietveld analysis indicates that the samples are nearly single phase. By fitting 

the experimental data with Vogel-Fulcher law, the relaxation time, characteristic 

temperature, magnetic anisotropy energy and effective magnetic anisotropy constant 

have been estimated. 

PJ01 

Magnetotransport properties of anisotropic Co(tCo)/Au(tAu) 

multilayers 

Conrad Rizal 1 , Parshu R. Gyawali 2 and Ramesh K. Pokharel 3 

1 

Electrical and Computer Engineering, University of British Columbia, Canada 

2 

Laboratory for Nanospintronics and Nanoelectronics, Catholic University of 

America, USA 

3 

Electrical and Communication Engineering, Kyushu University, Japan 

Artificially tailored Co/Au multilayers have been the subject of intense research in search of 

novel properties for potential applications [1] [2]. Earlier, we reported various components 

of giant magnetoresistance (GMR) effects and correlated them with microstructure of the 

isotropic multilayers [2]. In this work, we have investigated the effects of incident angle of 

deposition and magnetic annealing on GMR and magnetic properties of anisotropic Co/Au 

multilayers as the layer thicknesses of Co and Au are changed. We have investigated physical 

mechanisms responsible for various MR effects and correlated them with the existing 

models. The multilayers deposited at an oblique incident angle of 45 degree exhibited strong 

magnetic anisotropy. The maximum MR ratio is found to be 2.1 %. The transverse MR 

effect is always found to be larger than the longitudinal MR effect. These multilayers have 

been considered potential in developing biomagnetic technology. 

[1] E. T. Papaioannou et al. 'Magnetic, magneto-optic and magnetotransport properties of 

nanocrystalline Co/Au multilayers with ultrathin Au interlayers,' J. Nanosci. Nanotechnl, vol. 8, 

pp. 4323-4327, 2008. [2] C. Rizal, 'Study of magnetic anisotropy and magnetoresistance effects in 

ferromagnetic Co/Au multilayer films,' J. Magn. Magn. Mater., vol. 310, pp.e646-e648, 2007.

PJ02 

The new type of current and spin polarization oscillations 

Alexander I Kopeliovich and Pavel V Pyshkin 

theoretical physics, B.Verkin Institute for Low Temperature Physics and Engineering 

of the National Academy of Sciences, Ukraine 

In our work we found new type of spin polarization and current oscillations in 

conducting rings with inhomogeneous magnetic properties. In case of hydrodynamic 

electron transport (when frequency of electron-electron collisions is more than 

frequency of collisions that does not conserve momentum of electrons) we obtained 

spin hydrodynamics equations for non equilibrium electron spins when the electron 

spectrum was spatially inhomogeneous. We showed that in case of close conductor 

these equations had non zero solution in form of “spin pendulum” oscillations, 

i.e. oscillations of full current and spin polarization with frequency determined by 

characteristics of magnetic inhomogeneity. We found own oscillations of electron 

system in conducting ring consisting of two parts with different magnetic properties. 

For example it could be realized by connecting DMS and NMS conductors into a ring 

and placing it in magnetic field. We used equations similar to well-known two-current 

model and we showed that conductance of this system as a function of external EMF 

frequency had one maximum in hydrodynamic regime and this case was conform to 

'spin pendulum', and conductance had many maximums in a case of ballistic regime. 

These maximums vanished when magnetic properties of parts of the ring were 

identical. 

PJ03 

Pressure-enhanced giant magnetoresistance in Fe/Cr magnetic 

multilayers 

Gendo Oomi* 

Kurume Institute of Technology, Japan 

Pressure-enhanced Giant Magnetoresistance in Fe/Cr Magnetic Multilayers G 

Oomi1),S.Higashihara2),K. Suenaga2),K.Saito3),S.Mitani3) and K.Takanashi4) 

1)Kurume Institute of Technology,Kurume,Fukuoka,Japan 2)Department of 

Physics,Kyushu University,Fukuoka,Japan,3)Institute of Materials Research,Tohoku 

University,Sendai,Japan The giant magnetoresistance(GMR) of Fe/Cr magnetic 

multilayers has been measured under high pressure at low temperatures. It is found that 

the GMR on the second peak samples is enhanced strongly by applying pressure:the 

magnitude of GMR becomes twice at 2 GPa compared with the value at ambient 

pressure.The saturation magnetic fields of these samples decreases with increasing 

pressure.However the GMR of the first peak samples decreases with increasing 

pressure and the saturationfields increases with pressure. These sharp differences in the 

behaviour against pressure will be discussed phenomenologically. 

PJ04 

Spin current-induced by sound wave 

Igor Ivanovich Lyapilin 

Institut Metal Physics RAS, Russia 

In recent years, increased interest in studying the effects that arise in response to spin 

degrees of freedom of electrons, when the external perturbation acts on the kinetic 

degrees of freedom. As rule, the external perturbation (electric field) directly affects 

only the kinetic degrees of freedom of electrons and through spin-orbital interaction 

is transferred to the spin subsystem. There are other ways of influencing the system 

of conduction electrons, which are also reflected in the response of the spin degrees 

of freedom. So, in the ferromagnetic metals temperature gradient leads to the spin 

Seebeck effect. It is interesting to consider the mechanisms of interaction with 

external fields, in which the energy of the external field is transmitted simultaneously 

in both electronic subsystems (kinetic and spin). An example of such interaction is 

the interaction of conduction electrons with the field of sound waves. We studied the 

evolution of the electronic system for their interaction with the field of sound wave 

analysis of the conditions of occurrence and the the responce of the spin subsystem 

in a constant magnetic field. It is shown that in this case the longitudinal sound wave 

propagation arises transverse spin current, which has a resonant character. 

PJ05 

PJ06 

PJ07 


Enhancement of magnetocaloric width in La 2/3Ca 1/3MnO 3 compounds 

with remain the composition ratio between Mn 3+ and Mn 4+ 

Qing Ji and Xiaoshan Wu* 

Physics, Nanjing University, China 

Large magnetic entropy in a relative narrow transition temperature in manganites has 

been reported. To explore the enhancement of transition temperature width with large 

magnetocaloric properties, we here designed the samples with the same composition 

ratio of Mn 3+ and Mn 4+ , and the same averaged radius at each lattice sites, which we 

previously used to find the roles of the local Jahn-Teller distortion on the magnetic 

properties in manganites. Here, Y and Sr are used together to replace for La and Ca in 

La 2/3Ca 1/3MnO 3 (i.e., ABO3) to remain the average radius and the average valance at 

A-site. Results show that the averaged unit cell lattice parameters are unchanged. The 

ferromagnetic-to-paramagnetic transition temperature Tc increases abruptly owing to 

the increase of the competition between σ2 and double-exchange interaction resulting 

from Mn-O-Mn bond angle. The disordered distribution of cations at A-site broaden 

the phase transition temperature range (~T~10K or more) with large magnetic entropy 

of ΔSM=1.3 J/Kg K, which may be used as a promising candidate for magnetic 

refrigerant near room temperature. 

Output voltage calculations in double barrier magnetic tunnel 

junctions with asymmetric voltage behavior 

Artur Useinov, Jurgen Kosel and Aurelien Manchon 

King Abdullah University of Science and Technology, Saudi Arabia 

We studied the asymmetric voltage behavior of the tunnel magnetoresistance (TMR) 

for single and double barrier magnetic tunnel junctions (S&DMTJ) in range of a 

quasi-classical tunneling model. Numerical calculations of the TMR-V curves, output 

voltages and I-V characteristics for the negative and positive applied voltages were 

carried out using MTJs with CoFeB/MgO interfaces. Asymmetry is explained by 

different values of the minority and majority Fermi wave vectors for the left and right 

sides of the tunnel barrier, which can arises due to different annealing regimes. Electron 

tunneling in DMTJs was simulated in two ways: (I) Coherent tunneling, where the 

DMTJ is modeled as one tunnel system and (II) consecutive tunneling, where the 

DMTJ is modeled by two SMTJ connected in series. We found that DMTJs, in range 

of model I, the output voltage peaks will be shifted into the region of low voltages. For 

the model II, we found that, in order to provide symmetric output voltage branches in 

DMTJ, the conditions of equal Fermi vectors ratios have to be fulfilled for the left and 

right magnetic layers while ratio in the middle layer can be different. 

Spin-current manipulation by domain wall motion in the non-local 

spin valve 

Ryoko Sugano 1 , Masahiko Ichimura 1 , Saburo Takahashi 2 and Sadamichi Maekawa 3 

1 Central Reserach Laboratory, Hitachi, Ltd., Japan 

2 Institute for Materials Research, Tohoku University and CREST-JST, Japan 

3 Advanced Science Research Center, Japan Atomic Energy Agency and CREST-JST, 

Japan 

A spatially- and time-dependent magnetic spin texture exerts a spin-dependent force on conduction 

electrons[1]. In particular, spin-motive force generated by a domain wall motion has been theoretically 

investigated and experimentally observed by detection of electric voltage[2,3]. The spin-dependent field 

generated by spin-motive force is also expected to directly affect the non-equilibrium magnetization 

such as spin accumulation. In order to study the effect of the spin motive force on the spin accumulation 

in a lateral non-local spin-valve (NLSV) structure, we treat the NLSV device attached with a magnetic 

wire. The device consists of spin injector F1 and detector F2 strips bridged by an non-magnetic strip N 

and the magnetic wire is attached on N through the insulating layer in-between two magnetic stripes. 

A domain wall is introduced into F3 and driven by external magnetic fields. The spin-dependent field 

drives the pure spin current flowing in the N-channel. This effect can be detected as increase or decrease 

in the nonlocal spin-accumulation signals depending on the domain wall motion. We evaluated the 

spin-dependent field based on the LLG approach and calculate the spatial distribution of spin/charge 

current of this NLSV by applying a finite element method in three-dimensions. 

[1] S. Barnes and S. Maekawa, Phys. Rev. Lett. 98, 246601 (2007). [2] S. A. Yang et al., Phys. Rev. 

Lett. 102, 067201 (2009). [3] P. N. Hai et al., Nature 458, 489 (2009). 




PJ08 


The study of microwave assisted magnetization reversal via spin 

pumping 

Sankha Subhra Mukherjee, Siddharth Rao, Praveen Deorani, Jae Hyun Kwon, 

Charanjit Singh Bhatia and Hyunsoo Yang* 

ECE, National University of Singapore, Singapore 

There has been a significant interest to switch high coercivity magnetic bits for the 

future magnetic media by lowering the coercivity during the writing process. MAMR 

is a popular method of reducing the coercivity. We present a novel method of studying 

MAMR via spin pumping and the inverse spin Hall effect (ISHE). In this method, a 

Pt layer was placed in contact with a ferromagnetic (Py) layer, and an rf signal was 

applied to the Py via a coplanar waveguide during loop measurements. Due to the 

presence of the rf power, magnetization dynamics in the Py layer pumps spin in the 

adjacent nonmagnetic Py layer, which creates a measurable dc voltage across the Pt due 

to the ISHE. The measured signal is of the order of several microvolts and thus does 

not affect the magnetization by any significant amount. It also effectively decouples 

the input rf input from the dc output. The coercivity can be easily detected by the field 

at which there is a change in the polarity of the measured voltage. The coercivity as a 

function of the applied rf power is studied. 

PJ09 

Contributions of domain walls on large magnetoresistance effect in 

ultrathin TbFeCo wires 

Bang Do and Hiroyuki Awano 

Toyota Technological Institute, Japan 

Perpendicular anisotropy magnetic materials such as TbFeCo are expected to introduce 

large effectivity of spin-transfer torque and high domain wall (DW) motion speed as 

well as high magnetoresistance (MR) values. We investigated the size dependence 

of MR effect in TbFeCo wires. The 80-μm-length and different widths (1 to 80 μm) 

of Tb 26Fe 66.8Co 7.2 wire-patterns were designed by using electron beam lithography 

technique. The Tb 26Fe 66.8Co 7.2 films with different thicknesses of 6, 18 nm were grown 

by RF sputtering. It is found that MR values are strongly depend on injection current 

for all applied fields. Large MR values which up to 100% were observed at a low bias 

current and depend on DW structure inside the TbFeCo wires. On the other hand, the 

MR values rapidly reduced at large bias currents which induce magnon and phonon 

scattering effects. The introduction of DWs in a magnetic wire causes an increase in 

spin-dependent scattering inside the DWs and leads to an enhancement of resistivity 

expectedly. The well defined and controllable number of DWs inside magnetic nanowires 

will expectedly introduce a new technique to obtain high and multi-level MR 

values as well as high potentials on future magnetic devices. 

PJ10 

First-principles study of conductivity tensor in transition metals and 

alloys 

Yohei Kota* and Akimasa Sakuma 

Department of Applied Physics, Tohoku University, Japan 

Spin-orbit interaction which is a relativistic correction to electron motion influences the 

transport properties, so the resistance anisotropy and Hall effect appear in conductivity 

tensor. In the present work, we calculate the conductivity tensor of transition metals 

and alloys in first-principles by the Fermi-surface term of Kubo-Streda formula. To 

calculate the conductivity tensor and electronic structure with spin-orbit interaction, 

we employ the tight-binding linear muffin-tin orbital method based on the local 

spin-density approximation [1]. The substitution disorder of alloys is treated using 

the coherent potential approximation. The obtained anomalous Hall conductivity, 

anisotropic magnetoresistance ratio, and also normal resistivity in ferromagnets 

such as Fe-Co and Fe-Ni as a function of the alloys composition are quantitatively 

consistent with the available experimental measurements in terms of their magnitude 

and sign. In particular we find that the Hall resistivities reveal the nontrivial behavior 

against the magnetization which can be varied by the modification of the composition 

ratio. Furthermore, the intrinsic and extrinsic contribution of the Hall conductivity is 

comparable in these alloys systems. Also we show the calculation results about the spin 

Hall conductivity of nonmagnetic compounds obtained in similar frameworks. 

[1] I. Turek, et.at., Philos. Magaz. 88, 2782 (2008); I. Turek, et.al. Phys. Rev. B 65, 125101 (2002). 


PJ11 

Magnetoresistance of CoFe/Pt nano-contacts 

Muftah Al-mahdawi* and Masashi Sahashi 

Department of Electronic Engineering, Tohoku University, Japan 

Using an alumina-based Nano-Oxide Layer (AlO x- NOL) between with many nanoholes 

between two ferromagnets [1] has gained more interest in recent years both in 

their fundamental physics of spin-scattering off the confined domain-walls and in 

their applicability for next-generation hard-disk-drive reading heads. Also, spin-torque 

driven oscillations of the confined domain-walls has been reported [2]. Following 

the report by [3] that Pt is magnetized at the interface with Co, we examined the 

insertion of AlO x- NOL between the Co-rich Co 90Fe 10 and Pt. Film stack was (in nm): 

Underlayer/Co 90Fe 10 3/AlO x- NOL/Pt 2/cap. It was deposited using ion-beam sputtering 

and dc magnetron sputtering deposition. AlO x- NOL was prepared using Ion-Assisted 

Oxidation (IAO) process[1]. IAO process forms direct nano-contacts (NC) in NOL 

between the CoFe and Pt (1~2 nm in diameter, with

PJ14 

Domain wall configuration and magneto-transport properties in dual 

spin-valve with nanoconstriction 

Byong Sun Chun 1 , Chan Yong Hwang 1 , Han Chun Wu 2 , Mohamed Abid 3 , Su Jung 

Noh 4 and Young Keun Kim 4 

1 

Korea Research Institute of Standards and Science, Korea 

2 

Trinity College Dublin, Ireland 

3 

Ecole Polytechnique Federale de Lausanne/IPMC, Switzerland 

4 Korea University, Korea 

In this work, we use a synthetic antiferromagnet-based dual spin-valve (SAF-DSV) structure 

(i.e. the SV structure is doubled symmetrically with respect to the FM) and present the effect 

of the direction of the applied magnetic field with respect to nanoconstriction shapes on the 

magneto-transport properties including domain wall (DW) configuration and reversal process. 

We can tune the DW configuration and its reversal process from a vortex to a transverse type 

by changing the direction of applied magnetic field respect to the nanoconstricted SAF-DSV. 

When the field is applied in the perpendicular direction to the nanoconstricted SAF-DSV, the 

perpendicular magnetic moments are developed due to the transverse magnetization reversal 

mode and result in a multistep switching process. This multi step switching process reflects the 

pinning and depinning of a DW at the nanoconstriction. Our results also show an asymmetric 

depinning field. We demonstrate, if nanoconstriction is asymmetric along its length, i.e. 

expansions from both sides of the neck into the two nanowires are not identical, and then an 

asymmetric energy barrier to domain wall propagation is formed. This is due to the difference 

in DW width, which leads to an asymmetry in the domain wall depinning forces. 

PJ15 

Giant magnetocaloric effect of Mn 0.91Ca 0.09As thin film on Al 2O 3 (0001) 

Duong Anh Tuan 1 , Cho Sunglae 1 *, Dang Duc Dung 2 , Shin Yooleemi 1 and Jeon Seung 

Mok 1 

1 Physics, University of Ulsan, Korea 

2 Physics, Depart of General Physics, School of Engineering Physics Hanoi 

University of Science and Technology., Viet Nam 

The MnAs compound is promising to magnetocaloric effect (MCE) application [1]. It presents the 

first order phase transition from a ferromagnetic to paramagnetic ~ 318 K, which is accompanied by a 

structural transition from a hexagonal NiAs-type (α-MnAs) to orthorhombic MnP-type structure (β-MnAs) 

[2]. Recently, the room temperature giant magnetocaloric effect was obtained by substitution of Mn by 

Fe, Co, Cu or Cr in MnAs: Co-25 J/kgK at 4T, Cu-175 J/kgK at 5T, Cr and Fe-42 J/kgK at 5T [3-5]. 

However, there is less information about group II dopants such as Ca, Ba, and Sr in MnAs. In this work, 

we report the magnetism and transport properties of epitaxial Ca 0.09Mn 0.91As thin film on Al 2O 3(001) 

substrate. The RHEED and XRD results indicated that film were epitaxially grown on Al 2O 3(0001). The 

temperature dependent resistivity showed metallic and the temperature dependent magnetoresistance 

at 7 kOe showed a peak around 325K. The negative anomalous Hall effect was observed in Hall 

measurement. The magnetic measurement indicates that the sample is ferromagnetic with TC was around 

340K and display the giant magnetocaloric signal. The magnetization hysteresis loops exhibited the 

saturation magnetization (MS) was around 300 (emu/cm3) at 10K and 180 (emu/cm3) at 300 K. 

[1] L. Daweritz, Pep. Prog. Phys. 69, 2581 (2006). [2] J. Mira et al, Phys. Rev. Lett. 90, 097203 

(2003). [3] Wang et al, Appl. Phys. Lett. 97, 042502 (2010) [4] D. L. Rocco et al, Appl. Phys. Lett. 

90, 242507 (2007). [5]C. S. Mejia et al, Appl. Phys. Lett. 98, 102515 (2011). 

PJ16 

Anomalous Hall effect of [Amorphous CoSiB/Pt] multilayer films 

Hana Lee, Insung Park, Hyungjun Kim, Sungyong Kim, Youngkwang Kim, Hwayong 

Noh and Taewan Kim* 

Sejong university, Korea 

We have quantitatively investigated the Anomalous Hall effect (AHE) in [CoSiB/Pt] 

multilayer films. The [CoSiB/Pt] multilayers exhibited large Hall effect. In this study, 

we compared with the effects of the before and after of patterning. The [amorphous 

CoSiB 6A/Pt 14 A]n multilayers were deposited on SiOx substrate with a 30 A Pt 

and 50 A Ta buffer layer at the room temperature using a DC magnetron sputtering 

system. Thereafter the sample was patterned into a hall bar with the line width of 10 

μm. Hall effect measurements at room temperature were made up to 3 kOe with the 

applied magnetic field perpendicular to the film plane. The samples for the Hall effect 

measurement were prepared with a square geometry for the easy application of the Van 

der Pauw method to measure the Hall voltage of the samples. The applied current was 

50μA ~ 1 mA and the measured Hall voltage was in the range of several mV. 

PJ17 

PJ18 

PJ19 


Spin transport phenomena through MgO/CuPc hybrid barrier in 

magnetic tunnel junctions 

Yu Jeong Bae 1 , Nyun Jong Lee 1 , Tae Hee Kim 1 *, Hyunduck Cho 2 , Changhee Lee 2 , 

Luke Fleet 3 , Atsufumi Hirohata 3 , Yeong-ah Soh 4 and Gabriel Aeppli 4 

1 

Physics, EWHA Womans University, Korea 

2 

School of Electrical Engineering and Computer Science, Seoul National University, 

Korea 

3 

Electronics, The University of York, United Kingdom 

4 

London Centre for Nanotechnology, United Kingdom 

For realistic applications of organic spintronic devices, the investigation of the growth 

mechanism and electrical properties is of great importance to understand the spin transport 

phenomena in metal-organic hybrid systems. As the first step, we focused on surface 

morphology, growth mode, and thermal stability of thin Cu-phthalocyanine (CuPc) organic 

layers grown on metal surfaces covered with a few monolayer thick insulating films, such 

as MgO(001). Recent reports of achieving spin polarized tunneling across organic-inorganic 

hybrid barrier with significant magnetoresistance (MR) values at low temperature (< 10 

K) led us to study the organics semiconductor (OSC) thin films for substituting highly 

performing inorganic barriers. Therefore, we investigated systematically the spin transport 

phenomena through the OSC CuPc barrier with and without MgO(001) layer as a function of 

CuPc thickness. An epitaxial Fe(001)/MgO(001) layer was utilized as a spin injection layer, 

while a polycrystalline Co film as a spin detector. Here, we observed, for the MgO/CuPc 

hybrid barrier with a total thickness of ~ 3 nm, the high MR (> 200 %) values at 77 K and ~ 

10 % MR at 300 K in the Si(001)/MgO/Fe/MgO(001)/CuPc/Co hybrid tunnel junctions. 

Theoretical approach to spin-current absorption at an interface 

Kazuhiro Tsutsui 1 , Kazuhiro Hosono 2 and Takehito Yokoyama 1 * 

1 Dept. of Physics, Tokyo Institute of Technology, Japan 

2 Dept. of Physics, Tokyo Metropolitan University, Japan 

In the development of spintronic devices, techniques to detect spin currents efficiently 

are indispensable as well as the generation of spin currents. In general, the spin-current 

detection is demonstrated via the inverse spin Hall effect and the absorption of the 

spin current [1]. In this presentation, we theoretically examine the spin current induced 

by an inhomogeneous spin-orbit coupling due to impurities [2]. Using the Keldysh 

Green’s function formalism, we propose analytical expressions of the diffusive spin 

currents under an external electric field and find a spin-current generation in the 

presence of both gradient of the spin-orbit strength and that of the external field. 

The resulting diffusive spin current indicates the absorption of the spin current at the 

interface between materials with different spin-orbit strengths, which is exemplified 

with an experimentally relevant setup. 

[1] T. Kimura, Y. Otani, T. Sato, S. Takahashi, and S. Maekawa, Phys. Rev. Lett. 98, 156601 (2007). 

[2] K. Hosono, A. Yamaguchi, Y. Nozaki, and G. Tatara, Phys. Rev. B 83, 144428 (2011). 

Magneto-transport properties of Al 2O 3-doped Mn-Zn ferrites 

Hyo-jin Kim and Sang-im Yoo* 

Department of Materials Science and Engineering, Seoul National University, Korea 

We report the magneto-transport properties of Al 2O 3-doped Mn-Zn ferrites prepared 

by the conventional solid state reaction. Various amounts of Al 2O 3 were doped to 

a pure Mn-Zn ferrite to have the nominal composition of (Mn 0.8, Zn 0.2) 1-xAl xFe 2O 4 

(x = 0.03~0.1). Field dependency of magnetization was measured with a SQUID 

(superconducting quantum interference device) magnetometer, and low field 

magnetoresistance (LFMR) was also measured with the SQUID magnetometer using 

an external current source and voltmeter. The X-ray diffraction analyses revealed that 

all Al 2O 3-doped Mn-Zn ferrites of the spinel structure were a pure phase without the 

second phase. From the transport measurements of our samples in the temperature 

region of 100~300 K, it was found that with the addition of the Al 2O 3 dopant the 

resistivity level of the pure Mn-Zn ferrite was abruptly dropped over four orders of 

magnitude and further the LFMR ratio was greatly improved. High LFMR ratio over 

1.7% at 300 K in 0.5 kOe was achievable from 3mol% Al 2O 3-doped Mn-Zn ferrite 

without an appreciable increase in its resistivity. Detailed effects of the Al 2O 3 dopant 

on the microstructures, magnetic and magnetotransport properties of the Mn-Zn ferrite 

will be presented for a discussion. 




PJ20 


Current induced fluctuation of switching fields in Co/Pd nanowires 

Mahdi Jamali, Xuepeng Qiu, Kulothungasagaran Narayanapillai and Hyunsoo Yang* 

Electrical and Computer Engineering, National University of Singapore, Singapore 

Current induced effective magnetic fields in a thin metallic film of a ferromagnetic material 

sandwiched by two nonmagnetic materials have been studied intensively due to its potential 

applications for the magnetic random access memory [1, 2]. There is a controversy about 

the origin of the effective field such as the Rashba effect [3] or spin torque induced by the 

spin Hall effect [4]. We have recently observed current induced effective fields in nanowires 

made of Co/Pd multilayer [5]. The further investigation of the switching fields of nanowires 

reveals fluctuation in the switching fields upon an injection of different current densities. We 

have applied current pulses with a width of 2 ms and repetition of less than 1 Hz to minimize 

the Joule heating effect. At low current densities (J < 10¹¹ A/m²) there is a fluctuation in the 

switching field of the nanowire. For a certain value of the input current, the switching field 

of the Co/Pd nanowire increases(>6%). Furthermore, the switching fields in the positive and 

negative fields are not the same. The relative angle between the sample and magnetic field 

has changed and the effect of the angle on this fluctuation has been studied. 

[1] I. M. Miron, K. Garello, G. Gaudin, P. J. Zermatten, M. V. Costache, S. Auffret, S. Bandiera, 

B. Rodmacq, A. Schuhl, and P. Gambardella, Nature 476, 189 (2011). [2] T. Suzuki, S. Fukami, N. 

Ishiwata, M. Yamanouchi, S. Ikeda, N. Kasai, and H. Ohno, Appl. Phys. Lett. 98, 142505 (2011). [3] 

I. M. Miron, G. Gaudin, S. Auffret, B. Rodmacq, A. Schuhl, S. Pizzini, J. Vogel, and P. Gambardella, 

Nat. Mater. 9, 230 (2010). [4] http://arxiv.org/abs/1110.6846. [5] K. Narayanapillai, M. Jamali, and 

H. Yang, MMM conference, Arizona (2011). 

PJ21 

Role of structural inversion asymmetry on current-induced effective 

field in perpendicular magnetized trilayers 

Xuepeng Qiu, Kulothungasagaran Narayanapillai and Hyunsoo Yang* 


The fact that a current pulse can switch the magnetic moment of a perpendicular 

magnetized nanodot has attracted much attention for the next new generation spintronic 

devices [1]. However, the physical origin of this effect is still under debate. Here we 

report the pulse delta measurements in perpendicular magnetized substrate/2 MgO 2 Pt 0.8 

CoFeB 2 MgO (sample A) and substrate/2 MgO 0.8 CoFeB 2 Pt (in nm) micro-sized hall 

bar samples with opposite structural inversion asymmetry (SIA). For both structures, 

when the magnetic field applied along the current direction tilted off-plane by 2°, 

positive (negative) current induces a downward (upward) effective field with positive 

magnetic fields and the effective field direction switches with negative magnetic fields. 

The effective field is around 2,388 Oe per 10¹² A/m² in the sample A. For the other 

structure, the effective field shows a nonlinear correlation with the intensity of current. 

With small in-plane external fields, the magnetization can be switched by pulse current 

and the switching hysteresis was the same in the two structures. Our results suggest that 

the main contribution of the current induced effective field arises from the spin Hall 

effect rather than the Rashba or other SIA related effects. 

[1]. Ioan Mihai Miron, Kevin Garello, Gilles Gaudin, Pierre-Jean Zermatten, Marius V. Costache, 

Stephane Auffret, Sebastien Bandiera, Bernard Rodmacq, Alain Schuhl and Pietro Gambardella, 

Nature. 476, 189 (2011) 

PJ22 

Characterization of mechanically milled Cu-Co powder by 3D-FIB and 

atom probe tomography : effect of oxidation on the magnetoresistance 

Julien Bran, Rodrigue Larde, Malick Jean and Jean-marie Le Breton* 

Groupe de Physique des Materiaux - UMR 6634, CNRS - Universite de Rouen, 

France 

The Giant MagnetoResistance (GMR) effect discovered in 1988 [1] had inspired many researches on 

magnetoresistive materials. The resistance of the device is reduced with the application of a magnetic 

field and it is due to the spin dependent scattering effect. However, an inverse effect has been observed 

after an oxide phase introduction by Khan et al. [2]. This effect appears at low magnetic field and could 

be interesting for improving the sensitivity of magnetoresitive devices. In our study, a Cu 80Co 20 powder 

was elaborated by mechanical alloying under ambient atmosphere to investigate the oxide formation and 

its influence on magnetoresistive properties. 3D-Focused Ion Beam tomography (3D-FIB) and Atom 

Probe Tomography (ATP) [3] were used to characterize our samples. It was shown with 3D-FIB that 

after 1h30 of milling, the powder exhibits a lamellar structure with micro-sized Co rich regions. The APT 

experiments have revealed that after 20h of milling 1/3 of Co atoms is oxidized leading to the formation 

of nano-sized CoO clusters embedded in a Cu 85Co 15 matrix. These results bring crucial informations 

to correlate the structural properties with magnetoresistive properties of the Cu-Co-O powder and to 

understand the influence of the nano-sized oxide clusters on the inverse magnetoresistance. 

[1] M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, F. Petroff, P. Etienne, G. Creuzet, A. Friederich, and J. 

Chazelas, Phys. Rev. Lett., 61(21) (1988) 2472-2475. [2] H. R. Khan, A. Granovsky, M. Prudnikova, V. Prudnikov, F. 

Brouers, A. Vedyayev, A. Radkovskaya, J. Magn. Magn. Mater. 183 (1998) 379-386. [3] D. Blavette, B. Deconihout, 

A. Bostel, J. M. Sarrau, M. Bouet, and A. Menand, Review of Scientific Instruments, 64(10) (1993) 2911-2919. 


PJ23 

Effect of pressure on magnetotransport properties in Fe/MgO granular 

films 

A. Garcia - Garcia 1 , J. A. Pardo 2 , P. A. Algarabel1*, Z. Arnold 3 , J. Kamarad 3 and M. R. Ibarra 2 

1 ICMA, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain 

2 INA, Universidad de Zaragoza, 50018 Zaragoza, Spain 

3 Institute of Physics AS CR, 162 53 Praha 6, Czech Republic 

A special example of granular thin films is the discontinuous metallic and insulator multilayers (DMIMs) 

consisting of metallic layers with different degrees of discontinuity intercalated between insulating layers. 

However, the studies about the effect on the magneto-transport properties of the hydrostatic pressure are 

scarce[1]. In this work we report the effect of hydrostatic pressure on the resistance and magnetoresistance 

of a DMIM of nominal composition [Fe(t=0.7nm)/MgO(t=3 nm)]15 ,deposited on a substrate of corning 

glass. The DMIM has been characterized previously showing a superparamagnetic behaviour [2]. The 

resistivity has been measured at room temperatures with hydrostatic pressure (Ph) up to 7 Kbar. The 

resistivity decreases linearly with pressure, indicating an increase in conduction via tunneling. The value of 

the coefficient, (1/ρ0)dρ/dPh =-3.9 10-2 kbar-1 is higher than the value obtained in other granular films. This 

result implies that the electronic state of the DMIM is near the percolation threshold. Magnetoresistance (MR) 

isotherms have been measured at room temperatures for Ph=1bar and Ph=7Kbar. At the maximum applied 

magnetic field (3KOe) the MR increases from 0.6% at ambient pressure to 1.1% at 7 Kbar. This result will 

be explained due to the reduction of the tunnel barrier induced by the hydrostatic pressure. 

[1] G. Oomi, Miyawaga H., Sakai T., Saito K., Takanashi K., and Fujimori Hl. Physica B 284 1245 

(2000) [2] A. Garcia-Garcia, A. Vovk, J. A. Pardo, P. Strichovanec, C. Magen, E. Snoeck, P. A. 

Algarabel, J. M. De Teresa, L. Morellon, and M. R. Ibarra J. Appl. Phys. 105, 063909 (2009) 

PJ24 

Measurement of anomalous nernst effect in [CoSiB/Pt] multilayer 

films 

Ozgur Kelekci 1 , Ha Na Lee 2 , K. J. Min 2 , H. M. Waseem Khalil 1 , Tae Wan Kim 2 and 

Hwayong Noh 1 * 

1 Physics Department and Graphene Research Institute, Sejong University, Korea 

2 Department of Advanced Materials Engineering, Sejong University, Korea 

Recently, a new research field taking advantage of both spintronics and thermoelectronics, called spin 

caloritronics, has started to attract a great deal of attention [1]. In contrast to the Anomalous Hall Effect 

driven by electrical currents, Anomalous Nernst Effect includes combination of thermal and spin 

transport driven by a temperature gradient in ferromagnets. We have investigated Anomalous Nernst 

Effect in [CoSiB/Pt] multilayer films with perpendicular magnetic anisotropy. The layer structure 

of samples was SiO 2Ta 50APt 30A(CoSiB 6APt 14A)n. Standard Hall bars were patterned on the samples. 

Additionally, heating element was also patterned on the samples in order to apply temperature gradient. 

Nernst effect measurements were made up to 1.5 kGauss with the applied magnetic field perpendicular 

to the film plane. We obtained significant Nernst voltages (VN) by applying temperature gradient ∇T 

to the samples. Nernst voltage exhibited similar characteristic as AHE voltage due to the spontaneous 

magnetization. Samples with different number of [CoSiB/Pt] multilayers were measured and compared. 

VN increased with increasing number of layers. Dependence of VN on the heating power (P) and the 

distance from the heating element (d) have been investigated. We have extracted [VN] α [P] and [VN] α 

[1/d] dependencies from the measured samples. 

[1] G. E. W. Bauer, A. H. MacDonald, S. Maekawa, Solid State Commun., 150, 459, (2010). 

PJ25 

GMR effect in Co-Cu microwires 

Valentina Zhukova 1 *, Rastislav Varga 2 , Carlos Garcia 3 , Juanjo Del Val 1 , Mihail Ipatov 1 

and Arcady Zhukov 4 

1 

Dpto. de Fisica de Materiales, UPV/EHU, Spain 

2 

Inst. Phys., Fac.Sci., UPJS, Slovak 

3 

Dept Phys, Bogazici Univ, Turkey 

4 

Dpto. de Fisica de Materiales, UPV/EHU San Sebastian and IKERBASQUE, 

Basque Foundation for Science, Bilbao, Spain 

Granular materials exhibiting giant magnetoresistance (GMR) effect attracted considerable 

attention. For obtaining of the granular structures, melt spinning technique allowing rapid 

quenching from the melt is quite suitable. During last years considerable attention has been paid 

to the studies of glass-coated microwires produced by Taylor- Ulitovski technique allowing to 

achieve high quenching rate and producing amorphous, nanocrystalline, microcrystalline or 

even granular thin microwires. In this paper, we studied magnetic properties and GMR effect 

of Co x- Cu 100-x (10≤x≤30 at%) microwires and observed considerable magnetoresistance (MR), 

ΔR/R. For Co 10Cu90 microwires, ΔR/R increases when the temperature decreases, exhibiting 

negative MR, tending to saturate in high magnetic fields, H. On the other hand, for Co 30Cu 70 

samples ΔR/R(H) dependences showed non-monotonic behavior, exhibiting ΔR/R increase 

with H at low H-values (up to 5 kOe) and also considerable GMR effect. X-ray diffraction 

(XRD) results reveal that the structure of the metallic core is granular with two phases: the main 

one, fcc Cu (lattice parameter 3.61 Å) and fcc α-Co (lattice parameter 3.54 Å) which is present 

in microwires with higher Co content. In the case of low Co content, XRD indicates that Co 

atoms are distributed within the Cu crystals.

PJ26 

Domain wall quantum interferometer 

John Eves, N. Grisewood and H. B. Braun 

School of Physics, UCD, Ireland 

PJ27 

Synthesis and magnetic properties of trilayer NiFe/Bi/NiFe films 

Konstantin Patrin 1 , Viktor Yakovchuk 1 , Gennady Patrin 2 and Stanislav Yarikov 2 

1 Institute of Physics of Siberian Branch of Russian Academy of Sciences, Russia 

2 Siberian Federal University, Russia 

PJ28 

A study on the pulesd laser deposited metallic spin valve structures 

Sayak Ghoshal 1 * and P. S. Anil Kumar 2 

1 Physics, Indian Institute of Science, India 

2 Indian Institute of Science, India 

MOVED 

Earlier, it was found [1] that the bismuth spacer formation influences essentially the system 

magnetization. The shape of m(H) curve is changed with bismuth spacer thickness increasing. 

In particular, the test film with tBi = 0 has the narrow hysteresis loop and magnetization curve 

of a ferromagnetic type. For the films with tBi ≠ 0 the magnetization curves are typical for films 

possessing either by intra-layer anisotropy or by antiferromagnetic interlayer coupling. 

Since anisotropy is not experimentally observed, we attribute such a behavior to the presence of 

interlayer antiferromagnetic exchange. The investigations of electron magnetic resonance were 

made in NiFe/Bi/NiFe films. It was established that the magnetic resonance spectrum consists 

of solitary line for films with tBi = 0 nm and tBi = 15 nm, whereas for films with intermediate 

value of semi metal spacer the spectrum is superposition of two lines. Theoretical treatment 

of temperature dependences of resonance fields gives conclusion that the interlayer coupling 

depends on both bismuth interlayer thickness and temperature. Also, the magnetoresistivity of 

order of percent units and dependence of its value on thickness of bismuth spacer were found in 

these films at helium temperatures [2]. 

[1] G.S. Patrin, V.Yu. Yakovchuk, D.A. Velikanov. Phys. Lett. A, 363, 164 (2007) [2] G. S. Patrin, V. 

Yu. Yakovchuk, D.A. Velikanov, K.G. Patrin,and S.A. Yarikov. Bull. Russ. Acad. Sci. Phys., 76, 177 

(2012) 

It is envisaged that the conventional Spin Valve (SV) structures will be more 

advantageous over Tunneling Magneto-resistance (TMR) for the perpendicular 

magnetic recording due to the suitable RA product. Here Pulsed Laser Deposited (PLD) 

Spin Valve (SV) and Pseudo Spin Valve (PSV) samples are grown at room temperature 

with moderately high MR values using simple NiFe/Au/Co/FeMn structure. Although 

PLD is not a popular technique to grow metallic SVs because of its expected large 

intermixing of the interfaces, particulate formation etc., still by suitably adjusting the 

deposition parameters we could get exchange bias as well as more than 3% MR in 

the Current In Plane (CIP) geometry. Different SV and PSV samples are grown to 

study anisotropy effects, exchange coupling and exchange bias with anti-ferromagnet. 

Angular variation of the MR is also obtained which shows that the hard layer (Co) has 

a four-fold anisotropy in the NiFe/Co/Au/Co structures which becomes two-fold in 

presence of anti-ferromagnet. In this presentation, properties of these PLD grown SVs 

will be discussed in terms of the angular variation of MR, intermixing at the interfaces 

as well as details of exchange bias. 

(1) S. Yuasa et. al. J. Phys. D: Appl. Phys. 40 R337 (2007) (2) Y. Sakuraba et. al. Appl. Phys. Lett. 

94, 012511 (2009) 

PJ29 

PJ30 

PJ31 


Spin torque in a finite two-dimensional ferromagnet with Rashba 

interaction 

Christian Ortiz, Xuhui Wang and Aurelien Manchon* 

Physical Science and Engineering Division, King Abdullah University of Science and 

Technology, Saudi Arabia 

The interaction between a ferromagnetic exchange coupling and a Rashba spin-orbit 

interaction has shown its potential in magnetization switching [1, 2]. For such a system, 

a coherent theoretical framework has been developed to study the coupled spincharge 

diffusive dynamics [3]. Using finite element method, we numerically solve, 

in a two-dimensional (2D) electron system with appropriate boundary conditions, 

the generalized equations for the diffusive charge and spin dynamics. This numerical 

approach allows for an accurate description of the spin and charge dynamics (i.e. nonequilibrium 

accumulation and current) for a wide range of parameters beyond the 

limit of weak Rashba interaction [1,3]. The spatial profile of the spin accumulation 

exhibits a strong presence of a spin precession arising from both the s-d exchange and 

the effective Rashba field. Spin relaxations due to random magnetic impurities as well 

as the D’yakonov-Perel mechanism are embedded in the solution. We also discuss 

the diffusive dynamics and the spin torques in different regimes with respect to the 

magnitude of the Rashba spin-orbit interaction. 

[1] A. Manchon and S. Zhang, Phys. Rev. B. 78, 212405 (2008); 79, 094422 (2009). [2] I. M. Miron, 

et al. Nature (London) 476, 189 (2011). [3] X. Wang and A. Manchon, arXiv:1111.1216 (to appear 

on Phys. Rev. Lett.); arXiv:1111.5466. 

Spin transport of Py/Au/Py spin valves with different Au channel 

widths 

Jang Hae Ku 1 , Joonyeon Chang1*, Hyun Cheol Koo 1 , Jonghwa Eom 2 , Suk-hee Han 1 

and Gyutae Kim 3 

1 Spin Convergence Research Center, Korea Institute of Science and Technology (KIST), Korea 

2 Department of Physics, Sejong University, Korea 

3 Department of Electrical Engineering, Korea University, Korea 

Most previous studies on spin injection and transport were dealt with one dimensional diffusive model and 

two-dimensional consideration has been neglected for simplicity [1-2]. However, all of the lateral spin valve 

devices experimentally demonstrated are fabricated based on thin film technology so that it is indispensable to 

have spatial distribution of spin current in a non-magnetic channel [1-2]. Actually, some of the experimental 

data can’t be understood in terms of one-dimensional conduction model. Injected spin current usually produce 

inhomogeneous spin accumulation which appears to a different magnitude of spin signal (ΔR) depending on 

the position of voltage probes on the detector [3-4]. In the study, nonlocal spin valve (NLSV) measurements 

for lateral Permalloy(Py)/Au/Py spin valve devices with different Au channel widths were carried out in two 

viable voltage probe configurations. The larger channel width is at a fixed center to center channel length, the 

lower the magnitude of ΔR is in the NLSV, which is attributed to the increase in junction area and enhanced 

spatial distribution of spin accumulation. The voltage probe configuration strongly affects the spin valve 

signal owing to the non-uniform spin current distribution in lateral Au channel. 

[1] M. Johnson, Phys. Rev. Lett. 70, 2142 (1993). [2] F.J. Jedema, A.T. Fillip, and B.J. van Wees, 

Nature 410, 345 (2001). [3] T. Kimura, Y. Otani, and J. Hamrle, Phys. Rev. B. 73, 132405 (2006). [4] 

J. Ku, J. Chang, J. Eom, H. Koo, S. Han, and G. Kim, phys. stat. sol. (b) 244, No. 12, 4530 (2007). 

The effect of magnetic impurities in magnetic tunnel junction 

Sungjung Joo 1 , K.y. Jung 1 , B.c. Lee 2 , Tae-suk Kim 3 , K.h. Shin 4 , Mung-hwa Jung 5 , Jinki Hong 1 and K. Rhie 1 * 


2 Department of Physics, Inha University, Korea 

3 Department of Physics, Chonnam national University, Korea 

4 Spintronics Device Research Center, Korea Institue of Science and Technology, Korea 

5 Department of Physics, Sogang University, Korea 

Magnetic tunnel junctions (MTJs) have been extensively investigated for more than a decade, not only because 

of potential applications such as next generation memory devices or high frequency spin oscillators, but also 

due to scientific interest. The physical properties of MTJs are very sensitive to the conditions of interface 

formation and, therefore, it is essential to understand the various influencing factors to control interface quality. 

The effect of oxidizing the ferromagnetic layer on tunneling magnetoresistance (TMR) is one of the most 

interesting problems in MTJs. The ferromagnetic layer in MTJs was oxidized with varying O 2 concentrations 

and the corresponding effect on spin-dependent transport was studied. As expected from our previous results 

for MTJs with an over-oxidized AlOx tunnel barrier, a partially oxidized ferromagnetic layer plays an important 

role in spin-dependent transport. As the temperature is lowered, the junction resistance increases dramatically 

and the TMR is strongly suppressed. Increasing the O 2 concentration enhances the increase of resistance and 

suppression of TMR. This work supports our previous conclusion that oxidizing the ferromagnetic layer 

generates localized magnetic moments, which act as a scattering center for spin-polarized tunneling electrons. 

1. K.J. Rho, J.-S. Lee, K.B. Lee, J.-H. Park, J.Y. Kim, Y. Park, K. Kim, S. Joo, and K. Rhie, Phys. Rev. B 83, 

172408 (2011). 2. K. Lee, S. Joo, J. Lee, K. Rhie, T.-S. Kim, W. Lee, K. Shin, B. Lee, P. Leclair, J.-S. Lee, and 

J.-H. Park, Phys. Rev. Lett. 98, 107202 (2007). 3. T.-S. Kim and D.L. Cox, Phys. Rev. Lett. 75, 1622 (1995). 




PJ32 


Effect of cobalt layer thickness on the magnetic and magnetoresistance 

properties of asymmetrical Co/Cu multilayers 

Srikrishna Pandey, Pavel Nikolaev and Sivaram Arepalli* 

Department of Energy Science, Sungkyunkwan University, Korea 

A series of asymmetrical multilayer thin films of Co/Cu with a systematically 

varying cobalt layer thickness tCo= 10, 15, 20, 30, 40 and 50 A was prepared by 

DC magnetron sputtering technique to study the effect of tCo on its magnetization 

and magnetoresistance properties. The XRD pattern of the multilayers showed 

the polycrystalline nature with texture (111). The magnetization measurements at 

different temperatures of the series showed that change in tCo leads to the change in 

magnetic anisotropy of the multilayers and thus change in coercive field (HC). The 

magnetoresistance measurements at different temperature of the series of multilayer 

showed a temperature dependent giant magnetoresistance (GMR) due to the inelastic 

scattering of electrons by phonons and magnons. Moreover, an asymmetry in GMR 

curves at low temperature was observed because of the asymmetrical (pseudo spin 

valve) structure of the multilayer. 

PJ33 

Current-induced motion of a transverse magnetic domain wall in the 

presence of spin Hall effect 

Soo-man Seo 1 , Kyung-whan Kim 2 , Jisu Ryu 2 , Hyun-woo Lee 2 and Kyung-jin Lee 1 * 

1 Materials Science and Engineering, Korea university, Korea 

2 Physics, Pohang University of Science and Technology, Korea 

The electric manipulation of a domain wall (DW) in a magnetic nanowire is subject to the 

spin-transfer torque (STT) effect due to the coupling between local magnetic moments of the 

DW and spin-polarized currents [1]. Numerous studies on this subject have been performed to 

understand its fundamental physics [2] and to extend its potential to applications such as data 

storage and logic devices [3]. In this work, we study theoretically current-induced dynamics 

of a transverse magnetic domain wall in bi-layer nanowires consisting of a ferromagnet on top 

of a nonmagnet having strong spin-orbit coupling. Domain wall dynamics is characterized by 

two threshold current densities, J(WB) and J(REV), where J(WB) is a threshold for the chirality 

switching of the domain wall and J(REV) is another threshold for the reversed domain wall 

motion caused by spin Hall effect. The domain wall with a certain chirality may move opposite 

to the electron-flow direction with high speed in the current range J(WB) < J < J(REV) for the 

system designed to satisfy the conditions J(WB) > J(REV) and α > β where α is the Gilbert 

damping constant and β is the nonadiabaticity of spin torque. Micromagnetic simulations 

confirm the validity of analytical results. 

[1] J. C. Slonczewski, J. Magn. Mag. Mater. 159, L1 (1996); L. Berger, Phys. Rev. B 54, 9353 (1996). [2] 

A. Yamaguchi et al., Phys. Rev. Lett. 92, 077205 (2004); M. Yamanouchi et al., Nature (London) 428, 539 

(2004); M. Klaui et al., Phys. Rev. Lett. 94, 106601 (2005). [3] S. Parkin et al., Science 320, 190 (2008). 

PJ34 

Universal spin-hall effect in metallic thin films 

Xuhui Wang 1 , Jiang Xiao 2 , Aurelien Manchon 1 , and Sadamichi Maekawa 3,4 

1 

King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering 

Division, Thuwal 23955-6900, Saudi Arabia. 

2 

Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai 

200433, China 

3 

Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and 

4 

CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan 

Spin-orbit interaction fills the academic and industrial pursuit for an electrical manipulation of spins. 

Fabricated using the state-of-art nanotechnology, semiconductor and metallic thin films embedded between 

two asymmetric interfaces in the presence of spin-orbit interaction have attracted intensive theoretical and 

experimental interest in recent years. Spin Hall effect [1], voltage-controlled spin precession [2] as well 

as the recently observed spin-orbit torque [3] all stem from a careful design of spin-orbit coupling in the 

bulk or at the interfaces. We predict a large spin-Hall conductivity due to interfacial spin-orbit interactions 

in an ultrathin normal metal film that is sandwiched by two insulators. While providing a confinement, 

the insulator/metal interfaces also serve as a source to the spin-orbit interaction due to inversion symmetry 

breaking. More interestingly, the interfacial spin-orbit coupling gives rise to a universal spin-Hall 

conductivity that is independent of microscopic details of the interfacial spin-orbit interaction and is 

predicted to be much larger than that induced by bulk impurities. 

[1] Y. K. Kato, et al. Science 306, 1910 (2004). [2] H. C. Koo et al., Science 325, 1515 (2009) [3] A. 

Manchon and S. Zhang, Phys. Rev. B. 78, 212405 (2008); A. Chernyshov, et al. , Nature Physics 5, 

656 (2010);I. M. Miron, et al. Nature (London) 476, 189 (2011). 


PK01 

Controlling magnetic isolation and moment reversal of FePt (001) 

films by Cu capping nanoislands 

D. H. Wei 1 *, C. H. Chao1 and Y. D. Yao 2 

1 Institute of Manufacturing Technology and Graduate Institute of Mechanical AND 

Electrical Engineerin, National Taipei University of Technology, Taiwan 

2 Institute of Applied Science and Engineering, Fu Jen University, Taiwan 

We aimed to control the magnetic interaction of FePt(001) films by introducing Cu 

capping nanoislands for applications in magnetic recording and permanent magnets. 

Fe/Pt multilayers were prepared by e-beam evaporation onto MgO substrates, and the 

thickness of Cu capping layers was varied from 1 to 6 nm. Out-of-plane coercivity 

increases with increasing growth temperature, and the reduction of grain/domain 

size and intergrain interaction of FePt can be achieved. Cu could penetrate into FePt 

nanostructures along the grain boundaries and create a strain-energy modulation at the 

interface due to its lower surface energy. Studies of angular dependent coercivity show 

a tendency of a domain-wall motion shift toward rotation of reverse-domain type with 

Cu capping nanoislands. The intergrain interaction was confirmed from the Kelly- 

Henkel plot that indicated the strong exchange coupling between neighboring grains in 

pure FePt films, and the negative δM value was obtained while FePt films capped with 

Cu nanoislands. 

PK02 

Perpendicular magnetic anisotropy for annealed Co/Ir(111) ultrathin 

films 

Wen-yuan Chan, Du-cheng Tsai, Cheng-hsun Chang and Jyh-shen Tsay* 

National Taiwan Normal University, Taiwan 

Compositions and magnetic properties of Co/Ir(111) ultrathin films thinner than 4 

monolayers (ML) have been investigated. As the Co thickness increases to above 2 

ML, magnetic hysteresis appears in both the longitudinal and polar configurations 

as revealed using surface magneto-optic Kerr effect (SMOKE) technique. After 

annealing treatments, the observations of the attenuation of Co LMM Auger signal 

and chemical shifts to lower kinetic energy show that Co atoms diffuse into the Ir(111) 

substrate. At higher temperatures, the Kerr intensities in both the longitudinal and 

polar configurations decrease due to the reduction of Co overlayer. At a temperature 

interval, magnetic hysteresis appears only in the polar configuration. This shows that 

the magnetic easy axis of Co/Ir(111) could be stabilized in the direction of the surface 

normal by thermal annealing treatments. By systematical investigations for Co/Ir(111) 

ultrathin films thinner than 4 ML, a magnetic phase diagram has been established. 

Several phases are observed, including a nonmagnetic phase, canted out-of-plane 

anisotropy and perpendicular magnetic anisotropy. On the top of the Co/Ir(111), the 

introduction of Ag overlayer shows an oscillatory behavior of the Kerr intensities. 

Possible mechanisms of the charge transferring, quantum well effects and completeness 

of the Ag layer are discussed. 

PK03 

Anomalous easy-plane magnetocrystalline anisotropy of compressive 

strained (La,Ba)MnO 3 films 

Hong Zhu*, Jinzeng Tian, Lei Yang, Qingyong Duanmu, Lin Hao and Xiaoping Wang 

Department of Physics, University of Science and Technologh of China, China 

Magnetic anisotropy of manganite films is sensitive to the epitaxial strain. So far, in Ca- 

and Sr-doped manganite films, many authors reported that a lattice expansion induces 

easy magnetization in the corresponding direction. In this work, magnetocrystalline 

anisotropy of La 0.67Ba 0.33MnO 3 epitaxial films suffering large compressive strain 

on LaAlO 3 substrates (LBMO/LAO) has been investigated by using ferromagnetic 

resonance (FMR) technique. By mapping out the dependence of the FMR position on 

the angle between the applied magnetic field and crystallographic axes of the films, 

a large easy-plane anisotropy has been found in such compressive strained LBMO 

films, which is in contrast to the common tendency reported before. The excellent 

epitaxial crystallographic orientation gives rise to an observable fourfold symmetry of 

the in-plane anisotropy. The results are discussed by taking large tolerance factor and 

giant magnetostriction of Ba-doped manganites into account. In the phase diagram 

of temperature vs. tolerance factor for doped manganites, we noticed that LBMO 

has a larger tolerance factor but a lower Curie temperature than Sr-doped manganite, 

meaning that shrinkage of Mn-O-Mn bond length in LBMO is in favor of spontaneous 

magnetization, which in turn results in the anomalous easy-plane anisotropy in the 

compressive strained LBMO films.

PK04 

Magnetic reversal of Co/Pt multilayer depending on Co thickness and 

annealing temperature 

Seungha Yoon, Seungkyo Lee, Joonhyun Kwon, Junghyon Lee and B. K. Cho* 

Materials Science and Engineering, Gwangju Institute of Science and Technology, 

Korea 

Magnetic reversal behaviors in ferromagnetic thin films are continuously studied to 

achieve high performance of technological applications. Recently, CoPt multilayers 

and alloys have been an important issue in perpendicular magnetic anisotropy (PMA) 

applications. However, fundamental studies of the magnetic properties were not 

much presented. In this work, we present a magnetic reversal behavior of Ta(3.0 nm)/ 

[Co(x nm)/Pt(1.0 nm)]x3 /Ta(1 nm) multilayers, when the Co thickness varied from 

0.3 nm to 2.0 nm. The multilayers were deposited using DC magnetron sputter on Si/ 

SiO2 substrate, and annealed with various temperature after deposition. The magnetic 

and structural properties of the multilayers were measured using vibrating sample 

magnetometer (VSM) and x-ray diffraction (XRD) at room temperature. In addition, 

we observed the magnetic reversal behavior with magneto-optic Kerr effect (MOKE) 

microscope system, capable time-resolved domain observation. 

PK05 

Annealing effect on the microstructures and magnetic properties of [Fe/ 

Pt]16 multilayers on MgO (001) substrate 

Aimei Zhang1 , Weihua Zhu 2 and Xiaoshan Wu 3 

1 College of Science, Hohai University, China 

2 College of Science, Hohai Unviersity, China 

3 Physics, Nanjing University, China 

[Fe/Pt]16 multilayers are deposited on MgO (001) single crystal substrate by magnetic 

sputtering layer by layer with varying the substrate temperature from 150-500oC to 

explore the annealing effect on the microstructures and magnetic properties of the 

films. Results show that FePt alloy with L 10 phase forms at about 300oC, and reaches 

a completely ordered state at about 400 oC. FePt film depositing at above 300oC has 

(001)-preferred texture which shows that L 10-FePt film has perpendicular magnetic 

anisotropy. The out-of-plane coercivity increases with sample transforming from [Fe/ 

Pt]16 multilayers to L 10-FePt alloy. The out-of-plane coercivity for the morphology, 

which is confirmed to have the effects on the out-of-phane coercivity, with the 

continuing surface has an order higher than that for the granular surface. 

PK06 

Preparation and magnetic studies of room-temperature sputtered [Co/ 

Pt] multilayer films on glass substrates with perpendicular magnetic 

anisotropy 

Chiuan-fa Huang 1 , Hsian-yuan Wu 1 , An-cheng Sun 1 *, Fu-te Yuan 2 , Jen-hwa Hsu 2 , S. N. 

Hsiao 3 and H. Y. Lee 3 

1 

Department of Chemical Engineering & Materials Science, Yuan Ze University, 

Taiwan 

2 

Department of Physics, National Taiwan University, Taiwan 

3 

National Synchrotron Radiation Research Center (NSRRC), Taiwan 

Multilayer [Co 10/Pt 7.5]n films were deposited at room temperature (RT) on glass substrates with and 

without a Pt(111) underlayer. The thicknesses of each Co and Pt layer were set at 1 and 0.75 nm 

respectively. The stacking period, n, was varied from 1 to 6, leading to the total thickness of [Co10/ 

Pt7.5]n films from 1.75 to 10.5 nm. The results of magnetic studies indicate that the perpendicular 

magnetic anisotropy (PMA) of [Co 10/Pt 7.5]n films is strongly influenced by inserting a Pt(111) 

underlayer and the number of n. Surprisingly, [Co/Pt]n films exhibit PMA behavior with a Pt(111) 

underlayer when n exceeds 3 even the films were deposited at room temperature. However without 

a Pt(111) underlayer, the films will not exhibit PMA in all cases. The appearance of L11 phase is 

found related to the appearance of PMA in [Co 10/Pt 7.5]n/Pt(111) films. The [Co/Pt]n film is grown 

along Pt(111) resulting in the L11(222) orientation, which causes the easy axis along the 

plane normal. In this study, the microstructure at [Co 10/Pt 7.5]n/Pt(111) interface is also studied and 

will be presented, which is helpful for understanding the formation mechanism of PMA behavior in 

multilayer [Co 10/Pt 7.5]n structure prepared at room temperature. 

PK07 

Magnetic anisotropy in FeCo thin films 

Xiaoxi Liu*, Shinsaku Isomura and Akimitsu Morisako 

Department of Information Engineering, Shinshu University, Japan 

PK08 

PK09 


Sputtered FeCo films normally show magnetic anisotropy inside the film plane. It is 

believed that the magnetic anisotropy are due to the stray field of the magnet of the 

target. However, the details of the induced magnetic anisotropy are yet to be fully 

understood. In the present work, we have prepared FeCo films by both DC magnetron 

sputtering system and facing targets sputtering system. The magnetic properties, 

crystallographic properties, and microstructure of the films have been investigated. 

Films deposited by DC magnetron sputtering show isotropic magnetic properties in the 

film plane. However, films deposited by facing targets sputtering show strong magnetic 

anisotropy in the film plane. The magnetic anisotropy field increases from 40 Oe to 540 

Oe with the increase of the film thickness from 10 nm to 150 nm for films deposited 

by facing targets sputtering system. XRD results show that the (110) lattice spacing 

of FeCo films increases with the increase of films thickness from 10 nm to 40 nm. 

However, lattice spacing almost not changes with further increase of the film thickness. 

Of particular interest is thatiInternal stress of the films increased with the decrease of 

the film thickness. 

Magnetic domain wall energy of Co/Ni superlattice with perpendicular 

magnetic anisotropy 

Kentaro Toyoki, Yu Shiratsuchi* and Ryoichi Nakatani 

Osaka University, Japan 

Co/Ni superlattice is a promising material for spintronics devices, in which the magnetic domain 

walls carry information stored, owing to a perpendicular magnetic anisotropy and a high 

saturation magnetization. Despite the numerous studies on the magnetic domain wall motion of 

the Co/Ni superlattice, the magnetic domain wall energy density has not been reported. In this 

work, we present the experimental determination of the magnetic domain wall energy density 

of the Co/Ni superlattice with perpendicular magnetic anisotropy (PMA). We confirmed that 

the epitaxial growth of Co(111)/Ni(111) superlattice on the Ag(111)-buffered Si(111) substrate. 

Several parameters were determined to obtain the magnetic domain wall energy σW [1], i.e. 

the saturation magnetization MS, the PMA energy, and the magnetic domain period. From the 

dependence of the magnetic domain period on the ferromagnetic layer thickness, the dipole 

length, D0 (≡ σW/2πMS2), is estimated as 22.5±2.5 nm. Using the experimentally obtained 

MS (≈660 emu/cc), the magnetic domain wall energy density is estimated as σW = 6.4±1.4 

erg/cm2. The estimated σW is about three-times higher than those for L12-CrPt3[2], and about 

one-third of that for L10-FePt[3]. From the obtained values, the exchange stiffness constant is 

calculated as about 4.8×10-6 erg/cm, which is comparable to that of bulk-Co. 

[1] C. Kooy and U. Enz, Phil. Re. Rept. 15, 7 (1960). [2] Y. Shiratsuchi, M. Yamashita, R. Nakatani 

and M. Yamamoto, J. Mag. Soc. Jpn, 33, 447 (2009). [3] S. Okamoto, N. Kikuchi, O. Kitakami, T. 

Miyazaki, Y. Shimada and K. Fukamichi, Phys. Rev. B 66, 024413 (2002). 

Anisotropic Magnetoresistance of Co/Ni multilayers 

Chih_yung Chen 1 , James C Eckert 1 , Natalia Fear 1 , Sheena K. K. Patel 1 , Richard 

Sayanagi 1 , Patricia D Sparks 1 , E Shipton 2 and Eric E Fullerton 2 

1 Harvey Mudd College, USA 

2 University of California, San Diego, USA 

Co/Ni multilayers exhibit perpendicular magnetic anisotropy, relatively low magnetic 

damping and unusual magneto-transport characteristic that make them useful for 

spintronic devices. Anisotropic magnetoresistance was measured for sputtered Ni/ 

Co films: SiO 2Ta 40ÅPd 40Å(Co 2ÅNi Y) x10Ta 40Å,with Ni thicknesses from Y=2-14Å. Three 

AMR configurations were studied. Two configurations, varying the applied field vs. 

current angle, the applied field always in the plane of the sample, AMR1, and varying 

the applied field from in plane to out of plane, AMR2, provide similar information. The 

%AMR1 or 2 increases monotonically as the fraction of Ni increases and shows the 

expected cosθ 2 dependence. Rotating the sample with the field always perpendicular 

to the current, AMR3, we see anomalous angle-dependence for all samples, at all 

temperatures. At the sample orientation where a peak in the AMR is expected, there 

is a dip. The relative magnitudes of these contributions vary with temperature and Ni 

thickness. The magnitude of the AMR3 is approximately half the AMR2. At 5K, the 

magnitudes of all AMRs increase with Ni thickness except the AMR3 for the sample 

with 3Å of Ni is anomalously low. The temperature variations for AMR2 and AMR3 

are quantitatively different but each varies by approximately a factor of 3 from 5K to 

305K. 




PK10 


Interface perpendicular magnetic anisotropy in thick amorphous 

CoSiB film by Pt layer 

Insung Park, Hana Lee, Hyung Jun Kim, Sung Yong Kim, Young Kwang Kim and 

Taewan Kim* 

Department of Advanced Materials Engineering, Sejong Univ., Korea 

Recently, magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy 

(PMA) have attracted a lot of research interest, because they have a potential for 

spin transfer torque magnetic random access memories (MRAMs). Devices with 

perpendicular magnetic anisotropy have lower switching currents than devices with inplane 

magnetic anisotropy. We have investigated the interface perpendicular magnetic 

anisotropy (IPMA) of amorphous CoSiB thin film. CoSiB/Pt exhibited perpendicular 

magnetic anisotropy. The structure of samples was SiO 2Ta 50ÅPt 30ÅCoSiBx/Pt 30Å and 

SiO 2Ta 50ÅPt 30ÅCoSiBx. The thickness of CoSiB were varied in the range of from 2 to 

40Å. The sample without Pt capping layer exhibited perpendicular magnetic anisotropy 

at tCoSiB=10Å but the sample with Pt capping layer exhibited perpendicular 

anisotropy at lower thickness tCoSiB=5Å. Therefore, it was expected that IPMA 

properties of amorphous CoSiB on Pt layer was suitable for STT-MRAM. 

PK11 

Perpendicular magnetic anisotropy and superparamagnetism in Ta/ 

CoFeB/MgO structures 

C.c. Tsai 1 , H.m. Chen 2 , Chih-wei Cheng 2 , C.h. Shiue 2 , M.c. Tsai 2 , J. P. Singh 2 , C.w. Su 3 and G. Chern 2 * 

1 Department of Engineering and Management of Advanced Technology, Chang Jung 

Christian University, Tainan 71101, Taiwan, Taiwan 

2 Department of Physics, National Chung Cheng University, ChiaYi 62102, Taiwan, Taiwan 

3 Department of Electrophysics,, National Chiayi University, ChiaYi, 60004, Taiwan, Taiwan 

Collapses of tunnel magnetoresistance in perpendicular magnetic tunnel junctions have been reported 

recently[1-2]. These observations indicate that the coercivity of the reference layer and sensing layer 

behaves differently at low temperature. We extend to study the temperature dependence of a series 

of films with SiO2 substrate/Ta 5 nmCoFeB x nmMgO 1 nm, 1.5

PK16 

Ultrathin Co/Pt films with high thermal stability and large effective 

magnetic moment 

Prasanta Chowdhury*, Prabhanjan Dilip Kulkarni, Murali Krishnan and Harish C 

Barshilia 

Surface Engineering Division, National Aerospace Laboratories (CSIR), India 

PK17 

PK18 

WITHDRAWN 

Magnetic characteristics of amorphous [CoSiB/Pt]n multilayers 

Woosuk Yoo 1 , Kyujoon Lee 1 , Myung-hwa Jung 1 *, Insung Park 2 , Taewan Kim 2 , E.h.m. 

Van Der Heijden 3 and H.j.m. Swagten 3 

1 Dept of Physic, Sogang University Seoul. South Korea, Korea 

2 Dept of Physic, Sejong University Seoul. South Korea, Korea 

3 Department of Applied Physics, Eindhoven University of Technology, Netherlands 

The development of electronics demands an increasing effort in attaining more efficient 

electronic memories. The materials with perpendicular magnetic anisotropy (PMA) 

are important in applications of electronic memories. One promising new material is 

amorphous PMA multilayers [CoSiB/Pt]n with n the number of repeated bilayers. By 

using a VSM-SQUID measurement setup, the magnetic characteristics of the [CoSiB/ 

Pt]n are gained. The anisotropy constants k1eff, K1, K2 are obtained by fitting the 

hard-axis magnetization curve with GST equation. The hysteresis loops appear slanted 

increasing n. Furthermore magneto- optical Kerr effect (MOKE) imaging confirms 

magnetic domain wall motion. The coercive field is first increasing with n and after a 

maximum, decreasing with n. This result is caused by the RKKY coupling between the 

magnetic layers and the balance between the domain wall energy scaling with n and the 

magnetostatic energy scaling with n2. In addition the reversal process is not depending 

on the strength of the initial magnetization field. 

Effects of phase distribution and grain size on the effective anisotropy 

and coercivity of nanocomposite PtCo permanent alloy 

Tao Liu 1 , Pei Zhao 2 , Zhaohui Guo 1 , Wei Li 1 , Wei Sun 1 and Jingdai Wang 1 

1 Division of Functional Materials, Central Iron & Steel Research Institute, China 

2 Central Iron & Steel Research Institute, China 

Phase distribution and grain size are the key factors controlling the coercivity of 

nanocomposite permanent magnets. Feng et al. have investigated the effective anisotropy 

and coercivity of nanocomposite Nd 2Fe 14B/α-Fe magnets. [1] The latest research shows 

that the PtCo alloy is composed of nano-structured soft and hard magnetic phases. [2] This 

system can be used as an ideal model system for studying exchange coupling between the 

magnetically hard and soft phases. There exist three types of grain interfaces with different 

exchange-coupling strengths in nanocomposite PtCo permanent magnets. It is necessary to 

describe the proportions of the three kinds of grain interfaces for analyzing the influences 

of the exchange-coupling interactions on the magnetic properties. We assume that soft and 

hard phases distribute randomly in nanocomposite permanent magnets and that all grains 

have cubic shapes.We caculate the dependence of the coercivity Hc of a nanocomposite on 

the hard-grain size Dh. For a given volume fraction vh and soft-grain size Ds, Hc shows a 

maximum value as a function of the hard-grain size Dh, and the maximum position shifts 

to a smaller Dh with the decreasing volume fraction of the hard phase. We shows the 

comparisons between the calculated coercivity Hc and experimental results. 

[1] W.C. Feng, W. Li, et al., J. Appl. Phys. 98, 044305(2005) [2] Xiao Q F, Bruck E, de Boer F R et 

al. , J. Alloys Compd., 364,64(2004) 

PK19 

PK20 

PK21 


Perpendicular magnetic anisotropy and metal layer effect in MgO/ 

CoFeB/cap (cap = Ta, Ru, and Nb) 

Chih-wei Cheng, Tsung-i Cheng and G. Chern* 

Department of Physics, National Chung Cheng University, Chiayi 62102, Taiwan, 

Taiwan 

Perpendicular magnetic anisotropy (PMA) has been observed in MgO/CoFeB/Ta but 

not in MgO/CoFeB/Ru, indicating that the metal cap layer is crucial¹-². In this report, 

we extend the study to MgO/CoFeB 1.2 nmNb(1 - 5 nm) by sputtering and find again that 

PMA can be induced by Nb cap layer. Our experimental results also show that Nb and 

Ta have strong interface effect but the PMA occurs in a small window (~ 1 - 3 nm) 

while Ru shows much weaker effect and the induced interface anisotropy constant (Ki) 

is basically not high enough to overcome the bulk anisotropy contribution. 

Dependence of perpendicular magnetic anisotropy of CoFeB thin films 

on thickness of MgO overlayer 

Duong Duc Lam 1 , Frederic Bonell 1 , Shinji Miwa 1 , Yoichi Shiota 1 , Kay Yakushiji 2 , Hitoshi 

Kubota 2 , Takayuki Nozaki 2 , Akio Fukushima 2 , Shinji Yuasa 2 and Yoshishige Suzuki 1 * 

1 Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan 

2 National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research 

Center, Japan 

The CoFeB/MgO interface is known to favor perpendicular magnetic anisotropy (PMA) which 

is already found application in the efficient magnetic tunnel junctions and electric field control the 

magnetization. Recently, the PMA of CoFeB/MgO structure has been achieved in both experiment 

[1,2] and theory [3], however the origin of PMA is still ambiguous. In this scope, the structure 

Ta 5nmCo 10Fe 70B 20(0.9-2.0)nmMgO (0-6.0)nmTa 5nm (unit in nm) was investigated. All samples were fabricated by 

sputtering method on thermally oxidized Si substrates. We studied the dependence of the total magnetic 

moment and the effective magnetic anisotropy energy of the Co 10Fe 70B 20 layer. Magnetic anisotropy is 

found to be very sensitive to MgO thickness, favouring to perpendicular direction with thin MgO film 

(the maximum interface anisotropy was 1.74 erg/cm2 with the CoFeB/MgO 1nm structrure. Although 

thin MgO samples have thick magnetic dead layer, resulting in the reduction of total magnetic moment, 

only the existence of the magnetic dead layer cannot explain the change of the PMA. We found that the 

thickness of MgO overlayer plays the very important role for the direction of magnetic anisotropy easy 

axis. This work is supported by CREST, Japan Science Technology Agency, Japan. 

[1] S. Yakata et al, J. Appl. Phys., 105, 07D131 (2009) [2] S. Ikeda et al, Nature Materials., 9, 721- 

724 (2010) [3] H. X. Yang et al, Phys. Rev. B, 84, 054401 (2011) 

The study of MgO based surface anisotropy of CoFeB layer 

Dongseok Kim 1 , Kuyeol Jung 1 , Sungjung Joo 1 , Youngjae Jang 1 , Byungchan Lee 2 , 

Jinki Hong 1 and Kungwon Rhie 1 * 

1 Display and Semiconductor Physics, Korea University, Korea 


STT-MRAM (Spin transfer torque-magnetoresistive random access memory)[1] has considered 

as an outstanding candidate for the next generation memory device. Higher anisotropy constant 

K and low saturation magnetization Ms are required for the perpendicular magnetic layers 

to satisfy the high thermal stability and low current density for current induced magnetic 

switching. The PMA(perpendicular magnetic anisotropy) have been reported in Fe-Pt alloy[2] 

ordered by L10, Co/Pd multi-layer[3] and CoFeB-MgO[4,5]. We report the PMA of CoFeB 

based with MgO using amorphous paramagnetic FeZr buffer layer. Samples are deposited on 

SiO 2 substrate by RF magnetron sputtering machine at room temperature. The structures are 

SiO 2FeZr 2nmCoFeB(tCoFeB:0.5-2)/MgO 2.5nmTa 1nm (in nm) and annealing for 1 hour at 400°C 

. Figure 1 shows Hall resistance of PMA of CoFeB after annealing. During the annealing 

treatment, the lattice of CoFeB became BCC lattice structure along with crystal structure of 

upper MgO. Therefore, the interface anisotropy is formed between CoFeB and MgO layers in 

rather thin thickness. In summary, we observed the PMA in CoFe/MgO using the FeZr buffer 

layer. We obtain a high anisotropic constant K with a various conditions. This method can be an 

excellent candiate for PMA- MTJ with low critical current density. 

[1] Kishi, T. et al. IEDM Tech. Dig. 309 (2008) [2] Yoshikawa, M. et al. IEEE Trans. Magn. 44,25732576 (2008) [3] Mizunuma, 

K. et al. APL. 95, 232516 (2009) [4] S.Yuasa. et al. Nat. Mater. 3, 868 (2004) [5] S.Ikeda. et al. Nat. Mater. 9, 721 (2010) 




PL01 


BiFeO3 thickness dependence of exchange bias in polycrystalline 

BiFeO3/FeNi bilayers 

Xiaobo Xue 1 , Xueyong Yuan 2 , Wenbing Rui 1 , Biao You 1 , Qingyu Xu 2 and Jun Du 1 * 

1 

National Laboratory of Solid State Microstructures and Department of Physics, 

Nanjing University, China 

2 

Department of Physics, Southeast University, China 

Due to both ferroelectric and antiferromagnetic transition temperatures above room 

temperature, multiferroic BiFeO 3 has attracted much attention for uses in the electrical 

control of magnetic random assess memory. Exchange bias in ferromagnet (FM)/ 

antiferromagnet (AFM) bilayers has also attracted much attention because of its 

importance in developing magneto-electronic devices. Although there have been some 

reports on the exchange bias employing BiFeO 3 as antiferromagnetic layer, most of 

them the BiFeO 3 layers were grown epitaxially. In this presented work, single phase 

polycrystalline BiFeO 3 films were successfully grown on Si substrate with LaNiO 3 

buffer layer. Clear exchange bias were observed at room temperature in a series of 

BiFeO 3(t)FeNi(3.6nm) bilayers, in which t varies from 8 nm to 240 nm. With increasing t, 

both the exchange bias field and the coercivity increase sharply and approach maxima 

when t is about 40 nm, which is close to one half of the spin cycloidal modulation 

period (64 nm) of the bulk BiFeO 3 material. Our results suggest that the cycloidal 

spin structure may still exist in the polycrystalline BiFeO 3 film and the interfacial 

uncompensated pinned spins may be responsible for exchange bias in the BiFeO3/FeNi 

bilayer films. 

PL02 

Temperature-dependent magnetic anisotropies in epitaxial Fe/CoO/ 

MgO(001) system studied by the planar Hall effect 

J. Zhu 1 , J. Li 1 , W.n. Cao 2 , J. Zhu 1 and Yizheng Wu 2 * 

1 Physics department, Fudan university, China 

2 physics department, Fudan university, China 

The exchange coupling between ferromagnet (FM) and antiferromagnet (AFM) 

has been intensively explored due to fundamental interest and its technological 

applications. The effect of the magnetic anisotropy of the AFM layer on the exchange 

coupling has not been well studied, which can only be performed in single-crystalline 

FM/AFM system. In this contribution, we investigated the exchange-induced inplane 

magnetic anisotropies in a single-crystalline Fe/CoO/MgO(001) system in the 

temperature range of 10-400K. The temperature-dependent magnetic anisotropies of 

the Fe film were quantitatively measured with the torque technique utilizing the planar 

Hall effect. We found the field cooling can induce a very strong uniaxial anisotropy 

up to 0.196erg/cm2 in Fe film with the easy axis(EA) // CoO, and also a 4-fold 

anisotropy with the EA//CoO. Such EA of the exchange-induced anisotropy was 

found insensitive to the cooling field orientation and only related to the CoO crystalline 

axis. The CoO thickness dependent exchange-induced anisotropy will be discussed in 

this contribution. 

1.W. N. Cao, J. Li, G. Chen, J. Zhu, C. R. Hu, and Y. Z. Wu, Appl. Phys. Lett. 98, 262506 (2011) 

PL03 

Structural changes and magnetic properties of ultrathin Fe/Pt(111) 

films influenced by oxygen exposure 

Jyh-shen Tsay 1 *, Hau-chun Jhang 1 , Ying-chen Lee 1 , Wei-hsiang Chen 1 , Yao-jung 

Chen 2 and Huei-ying Ho 3 

1 National Taiwan Normal University, Taiwan 

2 Taipei College of Maritime Technology, Taiwan 

3 National Taipei University of Education, Taiwan 

Magnetic properties of Fe/Pt(111) films have received much attention in the past 

decade [1-2]. In this contribution, we focus on the structures and magnetic properties 

of ultrathin Fe/Pt(111) films influenced by oxygen exposure. Fe atoms in the 

submonolayer region adapt a smaller layer distance as compared to the BCC structure 

of a Fe layer above one monolayer (ML). At saturation conditions for absorbed oxygen 

on Fe/Pt(111), the increase of oxygen in the films coincides with the Fe thickness while 

the amount of adsorbed oxygen in the submonolayer range is rather small. In addition, 

the amount of oxygen exposure to achieve a saturation condition increases to a 

maximum value followed by a reduction for Fe/Pt(111) thicker than 1 ML. This shows 

the structure related oxidation efficiency of Fe/Pt(111). The growth of Fermi edge at 

620 K shows the segregation of Pt atom to the top layers. Only the Fe/Pt(111) thicker 

than 3 ML shows the enhanced coercive force after thermal annealing. This could be 

explained by the blocking of the formation of FePt alloy by the iron oxides. 

[1] T.U. Nahm, et al, J. Korean Phys. Soc. 46 (2005) S125; [2] Y.J. Chen, et al, APL, 93 (2008) 

012503. 


PL04 

Initial growth of bcc Co films on Au(001) studied by STM/BH imaging 

T. Kawagoe*, E. Wakabayashi, Y. Murasawa and T. Sakata 

Osaka Kyoiku University, Japan 

We have studied the surface structure and magnetism of metastable bcc Co films (>1 

ML) on Au(001) [1]. Here we report the initial growth of submonolayer Co films by 

means of barrier height (BH) imaging using STM, which has capability of element 

discrimination. The experiments were performed in a UHV-MBE system equipped 

with an STM unit. After the clean Au(001) reconstructed surface was confirmed by 

STM, a submonolayer Co was deposited on it at RT. Spatially resolved BH maps, 

together with the topographic images were obtained at RT using a tip-sample distance 

modulation technique. We have observed numerous islands with different sizes and 

heights after 0.15 ML Co coverage and successfully obtained, from the BH imaging, 

an element-specific contrast, i.e. recognizing aggregated Au islands and Co islands, and 

information about inhomogenities of BH with proper consideration of the artifacts near 

the step edges. BH of metastable bcc Co film was observed for the first time, and that 

showed a large BH value (~6 eV), whereas the observed BH of the Au(001) surface 

(~3.5 eV) was consistent with the previous results. 

[1] T. Kawagoe et al., Surf. Sci. 602, L15 (2008). 

PL05 

Magnetic field induced “switching” of the nanodomain state of 

ferromagnet - antiferromagnet frustrated system 

Alexander I Morosov and Alexander S Sigov 

Electronics Department, MSTU MIREA, Russia 

The presence of atomic steps on the interface between the nanolayers of ferromagnet 

and antiferromagnet with uncompensated atomic planes parallel to the interface causes 

frustrations of the interlayer exchange interaction. If the exchange integral for the 

ferromagnet is less than that one for the antiferromagnet, then, for the layers of equal 

thickness, and in the case where the characteristic distance R between the neighboring 

edges of the steps on the interface exceeds the layer thickness, the ferromagnetic 

layer appears to be broken down into 180 o domains. The domain walls separating 

such domains generated by frustrations arise at the atomic step edges and penetrate 

the ferromagnetic layer, the domain wall thickness increases with increasing distance 

from the interface. An external magnetic field applied parallel to the magnetizations 

of the domains, being in excess of some critical value B*, makes the monodomain 

state of the ferromagnetic layer more favorable. If so, the domain walls with more 

complicated structure depending on the field magnitude arise between 180 o domains in 

the antiferromagnet layer. The B* value can be obtained from the equality of the gain 

in the Zeeman energy and the difference between the energies of the domain walls in 

different layers. 

PL06 

Stable structural and electronic properties of adsorption Tl on the 

clean Tl/Si(111) surface 

Haruki Kato 1 *, Liang Li 1 , Shinya Haraguchi 1 , Junpei Goto 1 , Masahito Tsujikawa 2 and 

Tatsuki Oda 3 

1 Graduate School of Natural Science and Technology, Kanazawa University, Japan 

2 Center for Spintronics Integrated Systems, Tohoku University, Japan 

3 Institute of Science and Engineering, Kanazawa University, Japan 

The structural inversion asymmetry shows up surfaces or interfaces. It leads to spin split electronic 

state (Rashba-Bychkov effect) in the material. In particular, heavy metals on the light elements like 

Si show strong spin-orbit splitting [1] and such property in Tl/Si(111) has also been confirmed both 

in simulation and experiment [2]. This surface has been observed as a clean one, indicating the 

stability due to the insulating property verified by the experiments and theoretical approaches [3,4]. 

By donating (or accepting) electrons, one can introduce carriers with spin polarization at the part of 

states, implying an interesting basis for spintronics devices. In this work, as a method of donating 

electrons, Tl atom which is the same element as the top surface of Tl/Si(111) is considered within 

the density functional first-principles approach of fully relativistic pseudo-potential and planewave 

basis. First, the stable adsorption site has been investigated with using the √3×√3 superlattice of 

Tl/Si(111). It was found that one of hollow site models is most stable in the adsorption models 

investigated. In the presentation, we report details of the stable structure and, for typical systems, 

we also present electronic structures and spin splitting in the band dispersion relations. 

[1] C. R. Ast et al., Phys. Rev. Lett. 98, 186807 (2007). [2] K. Sakamoto et al., Phys. Rev. Lett. 102, 096805 (2009). [3] 

J. Ibanez-Azpiroz et al., Phys. Rev. B 84, 125435 (2011). [4] S. S. Lee et al., Phys. Rev. B 66, 233312 (2002).

PL07 

Exchange bias effect in Ni(Zn)O film 

R. Ray 1 *, S. Biswas 1 , S. Das 2 , S. Majumdar 2 and S. Giri 2 

1 Department of Physics, Jadavpur University, India 

2 Solid State Physics, Indian Association for the Cultivation of Science, India 

Exchange bias (EB) has received significant attentions for fundamental interest and 

potential applications in magnetic memory and read heads. Recently, EB is observed in 

various alloys and compounds [1]. Magnetic nanoparticles have been found promising 

for significant EB effect where surface spins were found to have different magnetic 

anisotropy than core spins, causing sizable EB effect. Compared to the studies of EB in 

nanoparticles, these studies in film geometry having chemically single phase are rarely 

investigated, which is rather promising for technological applications. Here, we report 

EB in Ni 1-xZn xO films where Zn substitution in NiO significantly modifies magnetic 

properties and EB effect. Atomic Force Microcopy exhibits formation of granular films 

of average grain size ≈25 nm. We note that EB field (HE) and coercivity (HC) decrease 

considerably with Zn substitution at x = 0.3 and HE vanishes at x = 0.5. Appearance 

EB in NiO film is suggested due to significant difference in anisotropy between core 

and surface spins, as it has been conjectured for NiO nanoparticles. The Zn substitution 

appreciably decreases the difference between core and surface anisotropy causing the 

reduction of HE as well as HC. 

[1] S. Giri et al. J. Phys.: Condens. Mater 23 (2011) 073201. 

PL08 

Electronic properties of transition metal oxides interface between 

GdTiO 3SrTiO 3 

Sungbin Lee 1 * and Leon Balents 2 

1 University of California, Santa Barbara, USA 

2 Kavli Institute for Theoretical Physics, University of California, Santa Barbara, USA 

The creation of a two dimensional electron gas (2DEG) at the interface between two 

insulating oxides has been a subject of great interest, and much experimental activity 

has centered on the LaAlO 3SrTiO 3 interface. The (001) GdTiO 3SrTiO 3 interface has 

the same naive polarization discontinuity as the former system, but unlikely it actually 

exhibits a 2DEG with the expected e/2 charge per planar unit cell.[1] Motivated by 

recent experiments, which show that the 2DEG primarily lives in the SrTiO 3, we 

construct a theoretical tight-binding model and discuss the electronic properties in 

comparison with experiment, and consider possible magnetism in this system at low 

temperature. 

[1] P. Moetakef et al., Appl. Phys. Lett. 99, 232116 (2011) 

PL09 

Parallel ferromagnetic resonance and spin wave excitation in 

exchange-biased NiFe/IrMn bilayers 

Marcos Sousa 1 *, Fernando Pelegrini 1 , Justiniano Marcatoma 2 , Willian Alayo 2 and 

Elisa Baggio-saitovitch 2 

1 Universidade Federal de Goias - UFG, Brazil 

2 Centro Brasileiro de Pesquisas Fisicas, Brazil 

Ferromagnetic Resonance (FMR) investigation of magnetron sputtered exchange-biased 

Si 111Ru 7nmNiFe tIrMn 6nmRu 5nm bilayers reveals that spin wave and uniform resonance modes 

are excited by the microwave field. The samples studied were produced in the presence of a 

400 Oe magnetic field to set the unidirectional anisotropy and the thickness t of the NiFe layer 

varied in the range 55-120 nm. The FMR experiments were done at room temperature using a 

commercial spectrometer with swept static magnetic field and the usual detection techniques. 

In-plane angular variation of resonance fields of spin wave and uniform modes reveal for both 

modes the dependence on cosθ, where θ is the field angle with respect to the anisotropy axis. The 

unidirectional anisotropy field for the spin wave mode is twice larger than that for the uniform 

mode; they are equal to 40 and 20 Oe, respectively, for the Si 111Ru 7nmNiFe 65nmIrMn 6nmRu 5nm 

sample. Spin wave resonance theory give for the NiFe layer of this sample the exchange constant 

of 1.2 × 10^(-6) erg/cm. The parallel FMR results at microwave frequencies of 9.45 and 34.1 

GHz agree with the values given by the resonance fields of spin wave and uniform modes also 

excited in perpendicular FMR at a frequency of 9.45 GHz. 

[1] W. Stoeklein, S. S. Parkin and J. C. Scott, Phys. Rev. B 38, 6847 (1988). [2] M. Nisenoff and R. W. Terhune, J. Appl. 

Phys. 36, 733 (1964). [3] V. S. Speriosu, S. S. P. Parkin, and C. H. Wilts, IEEE Trans. Magn. 23, 2999 (1987). 

PL10 

PL11 

PL12 


Morphological consideration for post-annealed Cr2O3 surface and 

exchange bias in bilayer system 

Tomohiro Nozaki*, Naoki Shimomura, Takuya Ashida, Yuji Sato and Masashi 

Sahashi 

Graduate school of Electronic Engineering, Tohoku University, Japan 

Magnetoelectric Cr 2O 3 has been received renewal of attentions as a promising material 

for the low energy consumption electric controlled spintronic devices such as MERAM 

[1]. High exchange bias field (Hex) between ferromagnetic layer and Cr 2O 3 thin film 

layer, and low coercivity (Hc) are essential for the applications. Previously we reported 

the high Hex (~500 Oe) at the wide temperature range from 10 K to 250 K and the low 

Hc (~30 Oe) at 250 K for post-annealed Cr 2O 3 thin film system [2]. In this study we 

compared the morphology and magnetic properties of the post-annealed sample with 

that of samples fabricated by other manners and examined the origin of the high Hex 

and low Hc of the post-annealed sample. The post-annealed sample was identified to be 

polycrystalline, which would contribute to the low Hc. From TEM and AFM images, 

flat (1-102) planes (r-planes) were observed diagonally to the film surface which are 

formed during the post annealing by grain growth due to the low surface energy [3]. 

From the fact that Cr 2O 3 has uncompensated spin not only c-plane but also r-plane, we 

conclude that the origin of the high Hex is the uncompensated r-plane. 

[1] X. Chen et al., Appl. Phys. Lett., 89 (2006) 202508. [2] T. Ashida et al., The 56th MMM 

<strong>Conference</strong>, (2011) FE-05. [3] J. Sun et al., Surf. Coat. Tech., 201 (2006) 4205. 

Magnetic properties of [NiFe/NiFeCuMo/NiFe]/FeMn¬multilayers 

depending on a thickness of NiFeCuMo layer 

Jong-gu Choi 1 , Kwang-jun Park 2 , Jang-rho Rhee 3 and Sangji-suk Lee 2 * 

1 Eastern-Western Biomedical Engineering, Sangji University, Korea 

2 Oriental Biomedical Engineering, Sangji University, Korea 

3 Physics, Sookmyung Women’ University, Korea 

Variations in the exchange bias field (HEX) and coercivity (HC) of the intermediately 

super-soft magnetic NiFeCuMo layer were investigated for different thicknesses of the 

bottom NiFe layer. HEX of the triple pinned NiFe 4 nmNiFeCuMo (tNiFeCuMo = 1 nm)/ 

NiFe 4 nmFeMn multilayer has a maximum value that is more less than that of a single 

pinned NiFe 8 nmFeMn layer. If a NiFeCuMo layer is inserted between the pinned and 

free NiFe layers, this multilayer system can be used as a giant magnetoresistive spinvalve 

(GMR-SV) device for biosensors with improved magnetic sensitivity. 

[1] J. G. Choi, D. G. Hwang, S. S. Lee, J. H. Choi, K A. Lee, and J. R. Rhee, J. Kor. Magn. Soc. 19, 

197 (2009). [2] J. G. Choi, D. G. Hwang, S. S. Lee, and J. R. Rhee, J. Kor. Magn. Soc. 19, 142 (2009). 

[3] J. G. Choi, D. G. Hwang, J. R. Rhee, and S. S. Lee, J. Magn. Magn. Mater. 322. 2191 (2010). 

[4] W. F. Egelhoff Jr., R. D. McMichael, C. L. Dennis, M. D. Stiles, F. Johnson, A. J. Shapiro. B. B. 

Maranville, C. J. Popwell, Thin Solid Films 505, 90 (2006). 

Structural and magnetic properties of antiferromagnetic Heusler 

Ru 2MnGe epitaxial thin films 

Naoto Fukatani*, Hirohito Fujita, Tetsuya Miyawaki, Kenji Ueda and Hidefumi 

Asano 

Nagoya University, Japan 

Recently, it is suggested that spin transport phenomena observed in conventional spintronics 

ought to occur in systems where all FM materials are replaced by antiferromagnetic (AFM) 

materials. Although various studies have investigated FM Heusler alloys, very few studies 

have been made on AFM Heusler alloys in terms of spintronic applications. The AFM 

transition temperatures (TN) of Heusler alloy such as Fe 2VSi can be controlled by inducing 

biaxial strain[1]. Thus we investigate the correlation between structural and magnetic 

properties of epitaxial thin films of AFM Ru 2MnGe. Structural characterization revealed 

that Ru 2MnGe films on MgO were subjected to compressive strain (c/a = 1.0042). The 

strained Ru 2MnGe exhibited markedly enhanced TN of 353 K compared to the bulk value 

(316 K)[2]. The in-plane Mn-Mn distance for the strained Ru 2MnGe is slightly smaller than 

that of bulk Ru 2MnGe, which may contribute to reducing the total J2 values, resulting in 

the enhancement of TN. We also observed the exchange coupling between Heusler-type 

FM half-metal Fe 2CrSi and AFM metal Ru 2MnGe. The present AFM Heusler alloy with 

relatively high TN is useful to fabricate high-quality all Heusler-type half-metal FM/AFM 

junctions and is a promising material for the emerging field of AFM spintronics. 

[1] N. Fukatani, C. Shishikura, Y. Takeda, and H. Asano, Appl. Phys. Expr. 2, (2009) 053001. [2] T. 

Kanomata, M. Kikuchi, and H. Yamauchi: J. Alloys Compd. 414 (2006) 1-7. 




PL13 


Exchange-spring phenomenon of ultrathin Fe/CoPt bilayer 

Wei-hsiang Chen 1 , Hsing-hsuane Wu 1 , Huei-ying Ho 2 and Jyh-shen Tsay 1 * 

1 Physics, National Taiwan Normal University, Taiwan 

2 Physics, Department of Science Education, National Taipei University of Education, 

Taiwan 

A large enhancement in the polar magneto-optic Kerr signal was observed after one 

monolayer (ML) of Co adatoms on Pt(111) was annealed above 600 K to form a Co- 

Pt alloy at the interface [1]. In this contribution, the composition, surface structure 

and magnetic properties of ultrathin Fe films on the top of a Co-Pt(111) surface alloy 

has been investigated. As the Fe coverage increases on the top of the Co-Pt alloy, the 

polar Kerr rotation increases. By way of systematically changing the Fe thickness, the 

magnetic properties of Fe/CoPt in both the polar and longitudinal configurations are 

investigated for Fe thinner than 7 ML. At an optimal condition for both the Fe thickness 

and the annealing temperature for preparing the Co-Pt alloy, the polar coercive force 

remains the same as the Fe coverage increases. The Fe/CoPt system exhibits magnetic 

exchange-spring behavior in the polar configuration. The interfacial conditions for the 

Fe/CoPt system are demonstrated to play an important role on the exchange-spring 

phenomenon and will be discussed in this contribution. 

[1] C.S. Shern, J.S. Tsay, H.Y. Her, Y.E. Wu, and R.H. Chen, Surf. Sci. Lett. 429 (1999) L497. 

PL14 

Neutron magnetic scattering study in manganite thin film system 

H. Nakao 1 *, H. Yamada 2 , K. Iwasa 3 , J. Okamoto 1 , Y. Yamasaki 1 , Y. Murakami 1 and A. 

Sawa 2 

1 Condensed Matter Research Center and Photon Factory, IMSS, KEK, Japan 

2 Electronics and Photonics Research Institute, AIST, Japan 


Perovskite manganites show various interesting phenomena including colossal magnetoresistance 

(MR) due to a close interplay among charge, orbital, spin, and lattice degrees of freedom. The 

superlattice [(LaMnO 3) m(SrMnO 3) m] n was investigated as a stage to control the Mn valence 

artificially. The physical properties were reported to strongly depend on the periodicity m, and 

the interface state between LaMnO 3 and SrMnO 3 layer was noted.[1] The stacking structure 

of Mn valence state by resonant x-ray scattering technique has been studied.[2] It elucidated 

that the physical properties just depend on the quality of the film. Recently, however, new large 

MR effect was discovered in the high quality superlattice system.[3] To understand the MR 

effect microscopically, the Mn valence state and the magnetic field effect were studied. Here the 

magnetism is also important, and then neutron magnetic scattering experiment was started using 

the neutron spectrometer TOPAN in JRR-3. As a first step, SrMnO 3 film with 80 nm thickness 

has been investigated. A signal with about 2 cps at (0.5, 0.5, 0.5) corresponding G-type AFM 

was certainly discovered. The temperature dependence of the signal intensity was also measured. 

Consequently we have succeeded in observing magnetic scattering from thin film system. 

[1] T. Koida et al., Phys. Rev. B 66 (2002) 14418. [2] H. Nakao et al., J. Phys. Soc. Jpn. 78 (2009) 

024602. [3] H. Yamada et al., Phys. Rev. B 81 (2010) 014410. 

PL15 

Direction and temperature dependences of exchange bias and 

coercivity of NiFe/Cr 2(1-x)Fe 2xO 3(x= 0.25, 0.4) bilayers 

Sanghoon Ki, Byeong-geon Kim and Joonghoe Dho* 

Kyungpook National University, Korea 

The antiferromagnets α-Fe 2O 3 and α-Cr 2O 3 have the same crystal structure but different 

magnetic orderings. The AF spin structure for a-Cr 2O 3(TN~307 K) is represented by 

the up-down-up-down spin ordering along c-axis, while that for a-Fe 2O 3(TN~953 K) 

is done by the up-down-down-up one. As reported in previous neutron diffraction 

study for the solid solution Cr 2(1-x)Fe 2xO 3(CFO), such contradictory spin structures 

may result in a new type AF structure such as spiral order or cycloidal order. Here, we 

report exchange bias in NiFe/Cr 2(1-x)Fe 2xO 3(x= 0.25, 0.4) bilayers grown on c-plane 

and r-plane Al 2O 3. The direction and temperature dependences of magnetic property 

of NiFe/CFO layer substrates were checked by a surface magneto-optical Kerr effect 

(SMOKE) setup. At room temperature, the M(H) loop of the NiFe layer exhibited 

enhanced coercivity and exchange bias depending on the measurement direction and 

the temperature. In order to see the direction dependence of magnetic property of NiFe 

layer, the magnetic field was applied to two orthogonal directions within the plane. 

Interestingly, the temperature dependence of M(H) loop exhibited some features of 

spin reorientation of CFO layer below antiferromagnetic transition temperature. 


PL16 

Structure and magnetic properties of epitaxial Fe/MgO/Si (001) 

heterostructures 

Jeong Hong Jo 1 , Kyung-ho Kim 2 , Yoon Jae Nam 3 , Hyung-jun Kim 2 , Joonyeon Chang 2 

and Sang Ho Lim 1 * 

1 

Department of Materials Science and Engineering, Korea University, Seoul 136-713, Korea 

2 

Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791, 

Korea 

3 

Department of Nano Semiconductor Engineering, Korea University, Seoul 136-713, Korea 

The ferromagnetic metal/semiconductor structures with inserting a thin MgO tunneling barrier are 

expected to play a key role in spin-based electronic applications to enhance spin injection efficiency. 

Recently, spin-based devices using silicon channel enable seamless integration with conventional 

MOS-FET technology. However, there are only a few reports on ferromagnetic metal/MgO/Si 

system due to large lattice mismatch (3.5%) between Si and MgO. The study on strain induced 

microstructure of the Fe and MgO layers is essential because the lattice mismatch between Si and 

MgO results in distortion in both MgO and Fe layers. In addition, the magnetic property of the 

ferromagnetic metal with respect to its microstructure evolution is also of importance in terms of 

spin injection. In this study, Fe thin films of thinner than 2 nm, were prepared on Si (001) substrates 

with 4 nm thick MgO buffer layer by a molecular beam epitaxy system at room temperature and 

200 °C, respectively. X-ray diffraction and reflection high-energy electron diffraction results show 

epitaxial relationship of the system. In-plane four-fold magnetic anisotropy was observed by 

vibrating sample magnetometer, suggesting that elevated growth temperature of the Fe films leads 

to the strain relaxation and the suppression of two-dimensional Fe layer formation. 

PL17 

Uncompensated magnetic moment around Mn 3Ir / Fe-Co-Ni bilayer 

interface 

Yohei Kota*, Hirokazu Takahashi, Masakiyo Tsunoda and Akimasa Sakuma 

Graduate School of Engineering, Tohoku University, Japan 

We study the microscopic origin of the uncompensated moment in Mn 3Ir / Fe-Co-Ni bilayer, 

which is practically utilized system due to the excellent property of exchange anisotropy, by the 

theoretical and experimental approach. In order to induce exchange anisotropy, the magnetic 

structure in the ferromagnetic / antiferromagnetic bilayer needs to have some asymmetry 

against the field reversal, and the uncompensated moments around the interface is a candidate 

for the spin asymmetry. We previously reported that there is a linear correlation between the 

exchange anisotropy and uncompensated moments measured by the x-ray magnetic circular 

dichroism (XMCD) experiment in Mn-Ir / Co-Fe bilayer [1]. Therefore, in the present work, we 

investigate the composition dependence of the uncompensated moment in Mn 3Ir / Fe-Co-Ni by 

performing the first-principles calculation and the XMCD measurement to clarify the origin of 

the uncompensated moment. In the comparison of the calculation and experimental results, the 

obtained uncompensated moments are in good agreement for their sign and relative magnitude 

[2]. Furthermore, the calculated result reveals that the uncompensated moment originates 

from the local magnetic correlation near the interface. So we find that the reorientation of the 

magnetic moments of Mn occur at the very interface with the ferromagnetic layer. 

[1] M. Tsunoda, H. Takahashi, T. Nakamura, C. Mitsumata, S. Isogami, and M. Takahashi, Appl. 

Phys. Lett. 97, 072501 (2010). [2] H. Takahashi, Y. Kota, M. Tsunoda, T. Nakamura, K. Kodama, A. 

Sakuma, and M. Takahashi, J. Appl. Phys. 110, 123920 (2011). 

PL18 

Unusual exchange bias effects in NiFe/Mn thin films induced via ionbeam 

bombardment 

Chi-hsin Liu 1 , Chin Shueh 1 , Yi-wen Ting 1 , Wen-chen Chen 2 , Te-ho Wu 2 , Johan Van Lierop 3 and Ko-wei Lin 1 * 

1 Dept of Materials Science and Engineering, National Chung Hsing University, Taiwan 

2 Graduate School of Material Science, National Yunlin University of Science and Technology, Taiwan 

3 Department of Physics and Astronomy, University of Manitoba, Canada 

When spins at the interface between a ferromagnet (FM) and an antiferromagnet (AF) couple, a 

unidirectional anisotropy occurs, resulting in exchange bias [1,2]. In this study, we wish to identify the 

dependence of the exchange bias on the interface microstructure in NiFe/Mn thin films. A series of [NiFe/ 

Mn] multilayer thin films were fabricated using a dual ion-beam deposition technique [3]. Different Ar-ion 

deposition voltages created striking differences in magnetic properties. The [NiFe/Mn] (VEH= 0 V, i.e. unbombarded) 

thin film (~ 200 nm) at 5 K when 20 kOe field-cooled (FC), exhibited an enhanced coercivity 

(Hc~ 935 Oe) and positive exchange bias field, Hex~ +130 Oe. By contrast, the [NiFe/Mn] (VEH= 150 

V) Ar-ion bombarded thin film (~ 20 nm) at 5 K when 20 kOe field cooled showed a larger positive Hex 

(~ +160 Oe) with smaller Hc (~ 610 Oe) accompanied by an asymmetric hysteresis loop. The observed 

enhanced positive Hex indicated that the transition from FM to AF coupling was made possible by 

changing the ion-beam bombardment voltages. Further, the role of Ar ion-bombardment seems to change 

both the spin orientations in FM NiFe and AF Mn and thus gives rise to the positive enhanced Hex. 

[1] T. Saerbeck, F. Klose, D. Lott, G.J. Mankey, Z. Lu, P.R. LeClair, W. Schmidt, A. Stampfl, S. Danilkin, M. 

Yethiraj, A. Schreyer, Phys. Rev. B 82, 134409 (2010). [2] H. Ouyang, Y.-H. Han, S.-C. Lo, C.-H. Su, Y.-R. 

Shiu, K.-W. Lin, R. D. Desautels, and J. van Lierop, Phys. Rev. B 81, 224412 (2010). [3] K.-W. Lin, V. V. 

Volobuev, J.-Y. Guo, S.-H. Chung, H. Ouyang, and J. van Lierop, J. Appl. Phys. 107, 09D712 (2010).

PL19 

Exchange bias effect in BiFeO 3 thin films 

Kil-dong Sung and Jonghoon Jung* 

Physics, Inha University, Korea 

We fabricated BiFeO3 thin films with Bi 2O 3 or γ-Fe 2O 3 impurities by changing oxygen 

partial pressures and characterized their magnetic properties. Since Bi 2O 3 impurity is a 

non-magnetic material, only antiferromagnetic spins of BiFeO 3 will contribute to whole 

magnetic properties. But γ-Fe 2O 3 impurity is a well known ferrimagnetic material, 

so there is a possibility to show exchange bias effect with antiferromagnetic spins of 

BiFeO 3. We measured M(H) loop at various temperatures after zero- and ±5 T-field 

cooling. Almost no but very small amount of M(H) hysteresis loop was appeared 

in BiFeO 3 with Bi 2O 3 impurity. Which indicate that there is uncompensated spins 

in BiFeO 3 which generate exchange bias effect with γ-Fe 2O 3. Significant hysteresis 

loop was appeared in BiFeO 3 with γ-Fe 2O 3 impurity. Depending on the field cooling 

direction, the M(H) loops also shifted to the opposite directions. But unlike other 

conventional exchange bias systems, the interaction between ferrimagnetic spins of 

γ-Fe 2O 3 and antiferromagnetic spins of BiFeO 3 is not so strong as shown in the training 

effect result. 

PL20 

Experiment evidence to the existence of interaction between 

antiferromagnetic domains in IrMn/Pt/Co/Pt multilayers 

X. J. Bai 1 , Z. Shi 2 , S. M. Zhou 2 *, X. R. Zhao 1 and C. D. Cao 1 

1 

Key Laboratory of Space Applied Physics and Chemistry, Northwestern 

Polytechnical University, Xi’an, China 

2 

Department of Physics, Tongji University, Shanghai 200092, China 

Exchange bias phenomenon has become an integral part of the modern magnetism, with implications 

in basic research and applications in magnetoelectronic devices. In the numerous experimental and 

theoretical studies, the surface layer of antiferromagnetic (AFM) material is often regarded as an 

assembly of uniaxial domains, which are independence from each other. This basic assumption is 

really suspect. In our presented work, experiment evidence of interaction between AFM domains has 

been found. The IrMn/Pt/Co/Pt perpendicular exchange bias systems were fabricated and treated by 

AC demagnetization (ACDM) parallel to the film plane at high temperature. The purpose of ACDM 

is to get the pinned demagnetization state in ferromagnetic layer. In the corresponding hysteresis 

loop, two minor-loops shift oppositely along the magnetic field axis and locate totally on one side 

of the vertical axis. Compare the training effects of the minor-loop and full-loop, we found that one 

minor-loop measurement gives influence to the other. It is reasonable that the influence is attributed 

to the interaction between the IrMn surface domains. Our experiment facts can not be explained by 

the past theory models, new energy item of interaction between AFM domains should be considered. 

[1] C. H. Lai, W. E. Bailey, R. L. White, T. C. Anthony, J. Appl. Phys. 81 4990 (1997) [2] T. Hauet, S. Mangin, J. McCord, F. 

Montaigne, and E. E. Fullerton, Phys. Rev. B 76, 144423 (2007) [3] X. P. Qiu, D. Z. Yang, S. M. Zhou, R. Chantrell, K. O’Grady, U. 

Nowak, J. Du, X. J. Bai, and L. Sun, Phys. Rev. Lett. 101, 147207 (2008) [4] E. Fulcomer, S. H. Charap, J. Appl. Phys. 43, 4190 (1972) 

PL21 

Nanoscale investigation of the Cr/Fe(001) interface grown by oxygen 

assisted epitaxy 

Alberto Brambilla 1 *, Andrea Picone 1 , Guido Fratesi 2 , Alberto Calloni 1 , Michele Riva 1 , Gianlorenzo 

Bussetti 1 , Alberto Ferrari 1 , Lamberto Duo' 1 , Marco Finazzi 1 , Mario Italo Trioni 3 and Franco Ciccacci 1 

1 Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy 

2 Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via Cozzi 53, 20125 Milano, Italy 

3 CNR, National Research Council of Italy, ISTM, Via Golgi 19, 20133 Milano, Italy 

Cr deposition on Fe(100) has been the subject of intense investigations in the past, being an excellent 

model system for thin film magnetism, and also because Fe/Cr multilayers played a fundamental role in the 

development of giant magneto resistive devices [1]. The magnetic properties of such systems can be affected 

by parameters like interfacial mixing, strain and defects. For instance, previous investigations have shown 

that, within the atom distribution resulting from Cr incorporation into the Fe substrate, nearest neighbour Cr- 

Cr coupling is energetically less favorable than next nearest neighbor coupling, due to magnetic frustrations 

[2]. Here we employ experimental and theoretical methods to highlight and characterize deviations in the 

micromagnetic structure of the Cr/Fe interface due to the presence of adsorbed O, which induces a layerby-layer 

Cr growth at room temperature, as we recently demonstrated [3]. Scanning tunnelling microscopy 

(STM) is used to investigate the deposition of Cr on the Fe-p(1x1)O surface since the first stages of interface 

formation. Atomic resolution STM images reveal the occurrence of different magnetic configurations, 

including first-neighboring Cr atoms in the Fe matrix. The observations are discussed in the light of densityfunctional 

simulations with the generalized gradient approximation and plane waves basis set [4]. 

[1] B. Heinrich, J.A.C. Bland (Eds.), Ultrathin Magnetic Structures, Springer Verlag, Berlin, (1994). [2] A. Davies, Joseph A. 

Stroscio, D. T. Pierce, and R. J. Celotta, Phys. Rev. Lett. 76, 4175 (1996). [3] A. Calloni, A. Picone, A. Brambilla, M. Finazzi, L. Duo, F. 

Ciccacci Surf. Sci. 605, 2095 (2011). [4] P. Giannozzi, N. Baroni, M. Bonini et al., J. Phys.: Condens. Matter 21, 395502 (2009). 

PM01 

PM02 

PM03 


Correlation of soft magnetic properties with free volume and medium 

range ordering in metallic glasses 

Amit P Srivastava 1 *, D Srivastava 1 , P K Pujari 1 , K G Suresh 2 and G K Dey 1 

1 Bhabha Atomic Research Centre, Mumbai, India 

2 Indian Institute of Technology Bombay, Mumbai, India 

The effect of cooling rate on thickness and soft magnetic properties of the metallic 

glass of alloy composition Co 64.5Fe 3.5Si 16B 14Ni 2 have been studied. The amorphous 

structure has been characterized by positron annihilation spectroscopy (PAS) and 

fluctuation electron microscopy (FEM) techniques. These studies suggest that the 

first lifetime component is associated with MRO present in the amorphous structure. 

Theoretical calculations showed that second component is associated with nanovoids 

having free volume equivalent to that of a vacancy defect consisting of 4 and more 

atom vacancy cluster. Coercivity of the samples showed small variations with wheel 

speed and it was found to decrease with the decrease in effective size of the defects 

present in the samples. This study reveals that, in case of amorphous metallic glass, the 

variation in coercivity is mainly controlled by the defects formed during processing 

rather than the small variations in MRO introduced due to different cooling rates. 

Microscopic magnetic hysteresis measurement of amorphous Tb-TM 

(TM=Fe and Co) thin films by magnetic Compton scattering 

Akane Agui 1 *, Tetsuya Unno 2 , Sayaka Matsumoto 2 , Kousuke Suzuki 2 and Hiroshi Sakurai 2 

1 Japan Atomic Energy Agency, Japan 

2 Dept. Production Sci & Technol., Gunma Univ., Japan 

Rare earth transition metal (RE-TM) alloys have attracted considerable attention from the viewpoint 

of fundamental research and technology. For instance, they have been studied as candidate heatassisted 

magnetic recording media for high-density magnetic storage. It is known that magnetic 

moment of RE and TM form ferrimagnetisms and have anisotropy dispersion along magnetic 

easy axes, so-called sperri-magnetism [1]. The magnetic switching process of sperri magnetism 

is considered not to be simple. In this report, we have study spin, orbital and also element specific 

magnetic switching process of amorphous Tb-TM (TM=Fe and Co) films by means of combination 

of magnetic Compton scattering [2, 3] and conventional macroscopic magnetization measurements. 

As specimen, amorphous Tb 43Co 57 and Tb 32Fe 55 (O 13) thin films were fabricated by an RF sputtering 

onto a thin Al foil substrates. The macroscopic magnetization curves were measured by SQUID 

and VSM magnetometers. Magnetic Compton scattering measurements were carried out at AR- 

NE1A of KEK [2] and at BL08W of SPring-8 [3], Japan. The present results suggest that magnetic 

switching can be different among the spin moment, the orbital moment, and even the states of 

electrons, e.g., the Tb 4f electron, TM 3d electron, and itinerant electron. 

References: [1] J. M. D. Coey, J. Chappert, J. P. Rebouillat, and T. S. Wang, Phys. Rev. Lett. 36 (1976) 1061. [2] A. 

Agui, H. Sakurai, T. Tamura, T. Kurachi, M. Tanaka, H. Adachi, and H. Kawata, J. Synchrotron Rad., 17 (2010) 321. [3] 

A. Agui, S. Matsumoto, H. Sakurai, N. Tsuji, S. Honma, Y. Sakurai, and M. Itou, APEX 4 (2011) 083002. 

A significant reduction of hysteresis in MnFe(P,Si) compounds 

O. Tegus 1 *, Y. X. Geng 1 and J. H. Huang 2 

1 

Physics and Electronic Information College, Inner Mongolia Normal University, 

Hohhot 010022, China 

2 

Baotou Research Institute of Rare Earths, Baotou 014030, China 

The magnetocaloric effects in Mn 1.3Fe 0.7-xCo xP 0.46Si 0.54 compounds with x = 0, 0.025, 

0.05 and 0.1 are studied systematically. X-ray diffraction shows that the compounds 

in the range from x = 0 to 0.1 crystallize in the Fe 2P-type hexagonal structure with 

space group P-62m symmetry. Magnetic measurements show that the paramagneticferromagnetic 

transition temperatures range from 247 to 298 K. The maximum of 

magnetic entropy changes in Mn 1.3Fe 0.7P 0.46Si 0.54 compound reaches 8.3 J/kgK in a 

field change of 0 to 1.5 T, and the thermal hysteresis of these compounds is less than 

3 K. The maximum adiabatic temperature change is 2.2 K in Mn 1.3Fe 0.7P 0.46Si 0.54 and 

Mn 1.3Fe 0.65Co 0.05P 0.46Si 0.54 compounds for a field change from 0 to 1.48 T. 





PM04 

Temperature dependence of creep-induced anisotropy in 

nanocrystalline FeCuNbSiB alloys 

Giselher Herzer*, Mie Marsilius and Christian Polak 

R&D Rapid Solidification Technology, Vacuumschmelze GmbH & Co. KG, Germany 

We have investigated the creep induced anisotropy in nanocrystalline 

Fe 75Cu 1Nb 3Si xB 21-x alloys as a function of the measuring temperature. The samples 

were produced by annealing originally amorphous ribbons for about 4 s between 500°C 

and 700°C with a tensile stress applied along the ribbon axis. For Si-contents equal 

or larger than 9 at% the annealed ribbons reveal a linear hysteresis loop indicative of 

an easy magnetic plane perpendicular to the stress axis. For lower Si-contents, stress 

annealing results in a square loop indicative of an easy magnetic axis parallel to the 

stress axis. This transition from an easy plane to an easy axis as a function of the Sicontent 

is well-known from previous investigations and is related to the dependence 

of local magnetostriction of the nanocrystals on the Si-content. However, the 

investigations so far have been only carried out at room temperature. The present work, 

for the first time, reveals that the Si-contents where the easy axis changes its direction 

shifts to higher concentrations as the temperature increases. This is also nicely reflected 

in a reversible change from a linear hysteresis loop with low remanence to a square 

loop as a function of the measuring temperature. 

PM05 

Magnetocaloric properties of Ni-Co-Mn-In ribbon 

M. U. Gutowska 1 *, J. Wieckowski 1 , A. Szewczyk 1 , W. Maziarz 2 , N. Nedelko 1 , S. 

Lewinska 1 , A. Slawska - Waniewska 1 , M. Kowalczyk 3 and A. Kolano - Burian 4 

1 

Institute of Physics, Polish Academy of Sciences, Warsaw, Poland 

2 

Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Cracow, 

Poland 

3 

Faculty of Materials Engineering, Warsaw University of Technology, Warsaw, 

Poland 

4 

Institute of Non-Ferrous Metals, Gliwice, Poland 

Temperature dependences of two parameters characterizing magnetocaloric effect (isothermal change 

in entropy and adiabatic change in temperature) were determined for a Ni 47Co 3Mn 35.5In 14.5 ribbon. Two 

experimental methods were used, i.e., measuring temperature dependences of a specific heat (from 3 to 

380 K) in zero magnetic field and in the field B=1 T, and measuring dependences of magnetization on 

temperature and on B. In the former method, both parameters were determined by analyzing the system 

entropy (determined by integrating the measured specific heat). In the latter method, the Maxwell relation 

was applied to get the isothermal change in entropy. The magnetocaloric effect shows two extrema of 

opposite sign, one near the transition between martensitic and austenitic phases, and the other one at 

the Curie temperature. The parameters characterizing the magnetocaloric effect near room temperature 

in relatively low B (1 T) make this material promising for application in magnetic refrigerators. The 

magnetocaloric effect was found to be highly anisotropic, being much larger for B applied in the ribbon 

plane. This property is particularly useful for designs, in which the active medium rotates in the field. 

This work was supported by the European Regional Development Fund, Innovative Economy Grants 

POIG.01.01.02-00-108/09, POIG.01.03.01-00-058/08 and POIG.02.02.00-00-025/09. 

PM06 

Influence of bismuth substitution on the magnetocaloric properties of 

Gd5Si2Ge2 compound 

Corneliu Bazil Cizmas 1 *, Rim Guetari 2 , Lotfi Bessais 3 , Najeh Thabet Mliki 2 and Sorin Adam 1 

1 

Department of Electrical Engineering and Applied Physics, Transilvania University 

of Brasov, Bd. Eroilor 29, 500036 Brasov, Romania 

2 

LMOP, Department of Physics, Faculty of Sciences of Tunis, Tunis El Manar 

University, 2092 El Manar, Tunisia 

3 

ICMPE, UMR7182 CNRS, Universite Paris-Est Creteil, 2/8 rue Henri Dunant, B.P. 

28 F-94320 Thiais, France, France 

In order to study the influence of relative small Bi addition on the magnetocaloric effect of Gd 5Si 2Ge 2, a 

series of Gd 5Si 2-xGe 2-xBi 2x (2x=0; 0.02; 0.04; 0.06 and 0.08) alloys was prepared by arc melting method. 

Investigations of Gd 5Si 2-xGe 2-xBi 2x properties where carried out using X-ray diffraction, thermomagnetic 

analysis, magnetization isotherms measurements and differential scanning calorimetry (DSC). After a heat 

treatment at 1250°C for 200 min., all the alloys have, at room temperature, a monoclinic structural phase 

of Gd 5Si 2Ge 2 type (S.G.: P112_1/a) with a small amount of hexagonal structural phase of Gd 5Si 3 type (S.G.: 

P63/mcm). The Curie temperature is around ~ 285K (±2K). The results of the DSC measurements show 

a difference of ~10K in the peak of the heating and cooling curves associated with a first order structural 

phase transition. The peak slightly decreases with Bi content. This is expected to be related to the 

increasing of the Si/Ge bond distance in the monoclinic phase with Bi addition. The maximum isothermal 

magnetic entropy change decreases with Bi addition, however a giant magnetocaloric effect was obtained 

for all alloys. As an example, the maximum magnetic entropy change for the Gd 5Si 1.98Ge 1.98Bi 0.04 was 

found to be 12.6 J/kg•K under an applied field of 5T. 


PM07 

Ion incient energy effects on the giant magnetoimpedance 

enhancement 

Hoon Song and D.g. Park* 

korea atomic energy research institute, Korea 

The present experiment investigates the physical effects of ion irradiation on the 

magnetic properties of the amorphous ribbon. Samples were commercial amorphous 

ribbon with sizes of 2 mm x 40 mm x 20 μm. The Ar ions were provided by an ion 

implanter at various dosages from 100 keV to 200 keV at the 1.0 x1018 ion/cm2. 

The GMI ratio was measured as a function of the DC magnetic field (Hmax=35 Oe) 

at different driving frequencies up to 10 MHz with a 5 mA amplitude applied to the 

sample irradiated with different energy. The irradiated samples show a clear change 

in the impedance response with applied field. When energetic ions with energies of 

several tens of keV penetrate into a thin film, the collision cascade cause displacements 

of the target atoms that induce a uniaxial anisotropy in the sample. Ion irradiation 

induces uniaxial anisotropy along the transverse direction, which is accompanied by an 

effective transverse susceptibility. Therefore, the increase in the GMI ratio in an ionirradiated 

sample is attributed to the increase in associated uniaxial anisotropy created 

by ion bombardment.We found that controlling the ion energy can be one of the 

effective ways of controlling the GMI property for ion 

[1] E. Lee, S. Lee, W. Lee and C. E. Lee, J. Korean Phys. Soc. 56, 2108 (2010). [2] D. Pathak and R. 

K. Bedi, J. Korean Phys. Soc. 57, 474 (2010). 

PM08 

Investigation of electrodeposited FeNi film prepared from tartaric acid 

based bath 

Takaya Shimokawa*, Takeshi Yanai, Ken-ichiro Takahashi, Masaki Nakano and 

Hirotoshi Fukunaga 

Nagasaki University, Japan 

FeNi films have been plated by using boric acid as pH buffer agent. However, the 

boric acid is needed to be replaced by another one which does not include boron, 

because boron is an environmentally hazardous substance. In order to achieve boronfree 

electroplating of FeNi, we applied the method proposed by Luisa et al for the 

CuNi electroplating [1] to that of FeNi, in which they successfully plated CuNi with 

good surface morphology by using tartaric acid. We electroplated FeNi films with 

Fe content of 17-45 at.% from the bath including NiSO 4•6H 2O, FeSO 4•7H 2O, NaCl, 

C 7H 4NNaO 3S•2H 2O and C 4H 6O 6 (tartaric acid). The content of Fe was controlled by 

varying the amounts of tartaric acid between 0-200 g/L. The coercive force of the asdeposited 

films varied with the content of Fe, and showed a sharp bottom of 20 A/m at 

around 22 at.% of Fe. This result is consistent with the fact that FeNi alloys have nearly 

zero values of magnetocrystalline anisotropy and saturation magnetostriction at around 

22 at.% of Fe. From the above result, we concluded that tartaric acid based bath film is 

one of hopeful plating bath for electroplating of FeNi films. 

[1] Luisa et al, J. Appl. Electrochem, 41 (2011) 415. 

PM09 

Electrodeposited Fe-Co film prepared from citric acid-based plating 

bath 

Takeshi Yanai*, Haruka Uto, Takaya Shimokawa, Ken-ichiro Takahashi, Masaki 

Nakano and Hirotoshi Fukunaga 

Nagasaki University, Japan 

Although a lot of the electrodeposited Fe-Co films with good soft magnetic properties 

were reported [1-3], boron, which is harmful and restricted by the regulation of 

environmental protection in Japan, was included in the plating bath as boric acid for 

controlling pH. Therefore, in order to remove boron, we focused on the citric acidbased 

plating bath and investigated effect of citric acid for the electrodeposited Fe-Co 

films. The plating bath was consisted of FeSO 4•7H 2O(100 g/L), CoSO 4•7H 2O(100 g/ 

L), NaCl(50 g/L), C 6H 8O 7•H 2O(0 - 270 g/L).An Fe plate as anode and a Cu plate as 

cathode were used, and Fe-Co film was deposited on the Cu plate. Current density 

was kept at 2 mA/mm2 and bath temperature was set at 50 °C during the deposition. 

The coercivity of the deposited film was drastically reduced from 1700 to 200 A/m 

with increasing content of citric acid from 0 to 100 g/L, and then slightly increased. 

The Fe-Co film prepared from the bath with citric acid of 100 g/L has high saturation 

magnetization of over 2.2 T and we can conclude that citric acid-based plating bath 

is one of hopeful plating ones to obtain good soft magnetic film with high saturation 

magnetization. 

[1] Qiang et al., Appl. Surf. Sci., 257 (2010) 1371. [2] Kockar et al., J. MMM, 322 (2010) 1095. [3] 

Teh et al., IEEE Trans. Magn., 47 (2011) 4398.

PM10 

Magnetic and magnetocaloric properties of polycrystalline Fe2P under 

hydrostatic pressure 

Luana Caron 1 *, Viktor Hoglin 2 , Yvonne Andersson 2 , Per Nordblad 3 and Ekkes Bruck 4 

1 

Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, TU Delft, Mekelweg 15, 

2629 JB Delft, The Netherlands, Netherlands 

2 

Department of Materials Chemistry, Uppsala University, Box 538, 751 21 Uppsala, Sweden, Sweden 

3 

Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala, Sweden, Sweden 

4 

Fundamental Aspects of Materials and Energy, TU Delft, Mekelweg 15, 2629 JB Delft, The 

Netherlands, Netherlands 

Magnetocaloric-based refrigeration presents itself as an environmentally-friendly energy-efficient technology 

capable of beneficially replacing the current gas compression-based technology. Some of the most promising 

magnetocaloric working materials found to date, such as (Fe,Mn)2(P,Si), are based on the Fe 2P binary 

compound. Fe 2P itself presents a first order magnetoelastic transition between FM and PM states at around 

219 K and a low magnetic entropy change spanning a large temperature range. What makes Fe 2P so 

unique is the coupling presented by its magnetic and crystal lattices which gives rise to the so-called mixed 

magnetism[1]. We believe that the mixed magnetism is responsible for the giant magnetic entropy change 

present in Fe 2P-based compounds. To further advance our understanding of this coupling we performed 

magnetization experiments under hydrostatic pressures up to 8 kbar on pure Fe 2P in its polycrystalline form. 

Pressure is found to decrease Tc at a rate of 6 K/kbar, about twice the rate reported in literature[2]. The Tc 

dependence on field is found to be non-linear and is only weakly affected by pressure. The magnetic entropy 

change peak is slightly decreased by increasing pressure whereas the total entropy increases by ~ 6%. 

[1] Dung, N.H. et al. Advanced Energy Materials 1, 1215 (2011). [2] Fujii, H., Hokabe, T., 

Kamigaichi, T. & Okamoto, T., J. Phys. Soc. Jpn. 43, 41-46 (1977). 

PM11 

Influence of Er doping on magnetic and magnetocaloric properties of 

(NiCo) 2MnGa 

Jiří Kaštil 1 *, Jiří Kamarád 2 and Zdenĕk Arnold 2 

1 Faculty of Mathematics and Physics, Charles University,Prague, Czech Republic 

2 Institute of Physics ASCR, Prague 8, Czech Republic., Czech Republic 

Recently, an attention has been paid to magnetocaloric properties of the Co-doped Heusler Ni 2MnGa 

alloys with a paramagnetic gap in martensitic phase that can be tuned by their composition [1]. The 

strong influence of a rare-earth doping has been calculated and observed on the valence orbitals 

of Mn that makes the main contribution to the magnetic properties of these alloys [2]. We have 

prepared Co-doped Ni 2MnGa alloys with a very small amount of Er. The polycrystalline sample of 

Ni 42.9Co 7Mn 31Ga 19Er 0.1 was checked by the EDX analysis and a segregation of Er was discovered on 

grain boundaries as it was expected in [2]. Saturated magnetization M(5K,0)=2.38μB/f.u. and the 

Curie temperatures TCM=318 K and TCA=440 K of martensite and austenite, respectively, were 

observed in Er free sample by a SQUID magnetometer. The inverse magnetocaloric effect at vicinity 

of martensitic transition, TM-A=379 K, was measured by direct method with ΔT=1.2K. In the Erdoped 

alloy, M(5K,0)=2.83μB/f.u. and paramagnetic gap was diminished in martensitic phase. 

TCA=450 K has been detected only and magnetic susceptibility obey nicely the Currie-Weis law with 

paramagnetic moment of mP=5.09 μB/f.u. above TCA. The effect of the Er-segregation on crystal 

texture and magnetic behaviour of the Co-doped Ni 2MnGa alloys will be discussed. 

[1] S. Fabbrici, J. Kamarad, Z. Arnold, F. Casoli, A. Paoluzi, F. Bolzoni, R. Cabassi, M. Solzi, G. 

Porcari, C. Pernechele, F. Albertini, Acta Materialia 59 (2011) 412-419 [2] J. Wan, Y. Fei, J. Wang, 

Journal of Rare Earths 24 (2006) 373-375 

PM12 

Structural and magnetic properties of FeMnAl nanocrystalline alloys 

Kontan Tarigan, Young-yeal Song and Seong-cho Yu* 

BK21 Physics Program and Department of Physics, Chungbuk National University, 

Cheongju 361-763, Korea 

Nanocrystalline magnetic alloys have been promising materials for magnetic device applications 

requiring high saturation magnetic flux density, high permeability, and low core loss. Among 

the magnetic alloys, Fe-Mn-Al system has been one of the most interesting tenary alloys with 

several magnetic phases. The magnetic properties were studied in one particular compound in 

previous works [1,2]. More systematic research of Fe-Mn-Al alloys would contribute to better 

understanding with Al contens. Nanocrystalline Fe 90-xMn 10Al x prepared via mechanical alloying 

using Fe, Mn, and Al powder with 48 hrs milling time. The structural and magnetic properties 

were studied. All peaks of XRD data are broader and shifted to smaller angle with increasing Al 

contents depending on the crystalline size and the lattice paramenter, respectively. All the samples 

exhibit alloys behavior with an average crystallite size around 10 nm. The magnetic saturation, the 

coercivity, and the permeability, obtained from measurements by vibrating sample magnetometer 

showed strong dependence on the Al contents, and these dependences were related to the changes 

in structure and crystallite size. In addition Mossbauer experiments confirm tha Al diffuses into 

Fe bcc grains. Furthermore, these results suggest that, by adjusting the Al content, appropriate 

structural transformation and appropriate magnetization values can be obtained. 

[1] Kontan Tarigan, Yong-Goo Yoo, Dong-Seok Yang, J. M. Greneche, and Seong-Cho Yu, IEEE 

Trans. Mag. 45, No. 6 (2009) 2492-2495. [2] E.A. Vela´squez, L.F. Duque, J. Mazo-Zuluaga, J. 

Restrepo, Physica B 398 (2007) 364-368. 

PM13 

Magnetocaloric effect in Fe doped La 0.67Ba 0.33MnO 3 system. 

Hirofumi Kawanaka 1 *, Hiroshi Bando 1 and Yoshikazu Nishihara 2 

1 Advanced Industrial Science and Technology, Japan 

2 Ibaraki Univ., Japan 

PM14 

PM15 


The perovskite-type oxides of La 0.67Ba 0.33Mn 1-xFe xO 3 were synthesized by the 

conventional solid-state reaction method. The Curie temperature Tc and magnetic 

entropy change (MCE) in these samples are determined and compared to those of Gddoped 

systems. [1,2] The Curie temperature Tc decreases from 350 K to 290 K with 

increasing Fe concentration x from 0 to 0.05. The relatively large MCE with a broad 

peak around Curie temperature compared with other oxides is observed in this system. 

These results suggest this system is a suitable candidate as magnetic refrigerator 

material working at room temperature. 

[1] Z. Juan, W. Gui, J. Magn. Magn. Mater. 321 (2009) 43-46 [2] M. H. Phan, S. C. Yu, J. Magn. 

Magn. Mater. 308 (2007) 325-340 

Study of magnetic transition and magnetic entropy changes of 

La 0.7Sr 0.3MnO 3 and La 0.7Ca 0.1Sr 0.2MnO 3 

Anwar Mohammad Shafique, Shalendra Kumar, Faheem Ahmed, G. W. Kim and Bon 

Heun Koo* 

School of Nano & Advanced Materials Engineering, Changwon national university, 

Korea 

Magnetocaloric effect (MCE) and its most straightforward application, magnetic 

refrigeration, are becoming fields of increasing research interest. On the one hand, 

there are reasonable expectations that these subjects will give rise to energy-efficient, 

environmentally friendly technological applications. On the other hand, the study 

of some model materials gives some more insight into the physics underlying these 

phenomena. In this paper, complex magnetic materials La 0.7Sr 0.3MnO 3, La 0.7Ca 0.3MnO 3 

and La 0.7Ca 0.1Sr 0.2MnO 3, suitable for the magnetic refrigeration, has been investigated. 

We have found that the substitution of the Sr with Ca leads to an important decrease 

of the Curie temperature (TC) from 374 K to 345 K. The magnetocaloric study 

exposes a quite large value of the magnetic entropy changes for La 0.7Ca 0.3MnO 3 

and La 0.7Ca 0.1Sr 0.2MnO 3. In cooling applications, another important parameter is 

relative cooling power (RCP), a good indicator of cooling efficiency of a magnetic 

refrigerant. For an applied magnetic field of 2 T, the RCP value is found to be 203 J/ 

kg for La 0.7Ca 0.1Sr 0.2MnO 3. As a result, the studied compounds could be considered as 

potential material for magnetic refrigeration near and above room temperature. 

Perpendicular magnetic anisotropy of amorphous ferromagnetic 

CoSiB multilayer 

Sol Jung 1 , H. I. Yim 1 *, Ahri Kim 2 and Sumin Kim 2 

1 Physics, Sookmyung Women's University, Korea 

2 Nano-Physics, Sookmyung Women's University, Korea 

Perpendicular magnetic anisotropy (PMA) is worthy of notice in both fields of science 

and industry due to its high integrate. In the previous study, we used CoSiB (75:15:10, 

atm%) and CoSiB/Pt multilayer showed the strong dependence on both the thicknesses 

of CoSiB and Pt. For the [CoSiB 3A/ Pt 14A]x5 multilayer, the maximum coercivity 

was ~ 224 Oe and the maximum PMA constant was obtained as ~ 2 × 10 6 erg/cm 31 . 

In addition, this film has the coercivity (Hc) and the saturation magnetization (Ms) 

with respect to 1.6 Oe and 407 emu/cm 3 . Considering this result, we suggest the new 

idea of CoSiB/Au/CoSiB sandwich structure and CoSiB/Pd multilayer. 1 mono-layerthick 

of Au and Pt are 144pm, 139pm and they are diamagnetic and ferromagnetic 

materials, respectively. CoSiB/Au/CoSiB sandwich structure and CoSiB/Pd multilayer 

is expected to show PMA and it can be developed to the magnetic random access 

memory (MRAM). 

[1] J. Y. Hwang, S. S. Kim, and J. R. Rhee, J. Magn. Magn. 310, 1943 (2007). [2] J. S. Park, H. I. 

Yim, J. Y. Hwang, S.B. Lee, T. W. Kim, J. Phys. Soc. 57, 1672 (2010). [3] S. Jeong, H. I. Yim, J. Phys. 

soc. 60, 450 (2012). 





PM16 

Thickness dependence of magnetic induction in inhibitor-free 3% 

silicon steels 

Sang-beom Kim 1 *, Joon-young Soh 1 , Sang-yun Lee 1 , Heejong Jung 2 and Jongryoul 

Kim 2 

1 Korea Electric Power Corporation Research Institute, Korea 

2 Department of Metallurgy and Materials Science, Hanyang University, Korea 

Cold-rolled sheets of differing thicknesses were prepared through the conventional 

hot and cold rolling process. After annealing at 1200°C, final texture greatly varied 

with heating rate and sheet thickness. The 0.2 mm thick samples contained no or 

few {110} grains within the tested range of heating rates, yielding a poor magnetic 

induction. On the contrary, the 0.15 mm thick samples consisted entirely of {110} 

grains, and consequently resulted in a very high magnetic induction of over 1.95 Tesla. 

The 0.1 mm samples were also composed of {110} grains either at a very slow or at a 

very fast heating rate, but they unexpectedly exhibited a poor magnetic induction due 

to the deviated direction of {110} grains from rolling direction. Orientation 

distribution functions of the samples taken from each cold rolling pass revealed that 

initial {111} texture components started to move toward {111} at a 

thickness of 0.13 mm. According to the nucleation and selective growth mechanism [1], 

primarily recrystallized texture takes after cold rolling texture, and hence the deviated 

final texture was obtained. This study indicates that there exists an optimum thickness 

for obtaining high magnetic induction and low iron loss. 

[1] N. H. Heo et al., Acta Mater. 51 (2003), 4953-4964. 

PM17 

Effect of M (= Ge, Y, Hf) addition on soft magnetic properties of Fe-B- 

Si-M metallic glass alloys 

Juho Lee 1 , Hwijun Kim 1 , Jungchan Bae 1 and Dohyang Kim 2 * 

1 Korea Institute of Industrial Technology, Korea 

2 Center for noncrystalline Materials, Yonsei University, Korea 

Fe-based metallic glass (MG) alloys exhibit good soft magnetic properties such as 

low coercivity and core loss but have the limits for industrial application because of 

low saturation flux density below 1.5T. Therefore, Fe-based MG alloys with high 

saturation flux density above 1.7T are very attractive soft magnetic alloy systems. In 

order to investigate the effect of M(= Ge, Y, Hf) addition on soft magnetic properties 

of Fe-B-Si-M metallic glass alloys, structural variations and magnetic properties 

of Fe 83-XB 10Si 7M X (X=1~5 at atomic percent) MG alloys were examined by X-ray 

diffraction(XRD) and vibration sample magnetometer(VSM) after fabricating 

Fe 83-XB 10Si 7M X MG ribbons by a single-roller melt-spinning technique under 

argon atmosphere. The thermal stability was measured by Differential Scanning 

Calorimetry(DSC) at a heating rate of 20K/min. Fe 83-XB 10Si 7M X MG alloys added Ge, 

Y or Hf exhibited a fully amorphous structure. Saturation flux density and coercive 

force of these alloys were Bs = 1.6~1.8T and Hc = 20~40 A/m, respectively. After 

annealing for 1 hr at 773K, Fe80B10Si7Ge3 MG alloy displayed excellent soft 

magnetic properties such as saturation flux density of 1.8T and corecivity of 20A/m. 

PM18 

Effects of film composition and substrate temperature on the structure 

and magnetic properties of FeCoB alloy films formed on MgO singlecrystal 

substrates 

Yugo Asai*, Mitsuru Ohtake, Tetsuroh Kawai and Masaaki Futamoto 

Chuo University, Japan 

Tri-layer films consisting of FeCoB and MgO layers have been investigated for MTJ applications. 

Theoretical studies show that the TMR ratio of MTJ prepared using epitaxial layers is one order of 

magnitude greater than that obtainable with amorphous layers [1,2]. The structure of bulk FeCoB 

alloy changes from crystalline to amorphous as the B content exceeds around 10 at. %. However 

in a form of thin film, there is a possibility of crystallization for B rich compositions. In the present 

study, (Fe 0.7Co 0.3) 100-xB x (x = 0-15 at. %) films were sputter deposited on MgO substrates of (100), 

(110), and (111) orientations at different substrate temperatures to investigate the effects of film 

composition, temperature, and substrate orientation on the structure and magnetic properties. 

Epitaxial films were obtained for all compositions by adjusting substrate temperature. For example, 

(FeCo) 95B 5 and (FeCo) 85B 15 epitaxial films were respectively obtained at temperatures higher than 

200 and 600 °C, while amorphous films were formed below these temperatures. The epitaxial 

films formed on MgO (100), (110), and (111) orientations consisted of bcc(100), bcc(211), and 

bcc(110) crystals, respectively. The magnetocrystalline anisotropy decreased with increasing the B 

content. Improved soft magnetic properties were realized in films with high B contents. 

[1] W. H. Butler, X.-G. Zhang, T. C. Schulthess, and J. M. MacLaren: Phys. Rev. B., 63, 054416 

(2001). [2] J Mathon and A Umerski: Phys. Rev. B., 63, 220403 (2001). 


PM19 

Arrangement of different magnetic alloy sheets for effective magnetic 

shielding 

Sang-yun Lee, Yun-seog Lim, Ho-seong Ahn, Dong-il Lee and Sang-beom Kim* 

Korea Electric Power Corporation Research Institute, Korea 

The purpose of this study is to provide an effective shielding method for power 

frequency magnetic field emanating from a neutral ground reactor (NGR). The 

0.35 mm thick commercial grade grain-oriented electrical steel (GO), non-oriented 

electrical steel (NGO), and permalloy (PC) were used as shielding materials. The area 

of 1200x1200 mm2 was blocked with the alloy sheets at a place 600 mm away from 

the NGR. In a weak magnetic field, PC is the best in shielding performance, whereas 

GO is the best in a strong magnetic field. NGO is worse than GO, but is better than PC 

in a very strong magentic field. For multi-layered shields, it was observed that GO/PC 

pair (GO is close to source) was most effective, yielding a shielding factor less than 

0.06 in the wide range of magentic fields. These results are explained by variation of 

shielding effectiveness of a magnetic material with magnitude of magnetic field. The 

inner GO sheet effectively shields a strong magnetic field first, and then the outer PC 

sheet effectively shields the weakened field. Furthermore, this study demonstrates 

some spacing between laminations is essential to achieve best shielding performance in 

the ‘shunt’ mechanism of magnetic shielding. 

PM20 

Fabrication of pariculated Fe-Mg thin films by selective oxidation and 

their magnetic properties 

Pyungwoo Jang* 

College of Science and Engineering, Cheongju university, Korea 

It is impossible to manufacture Fe-Mg bulk alloys even in vacuum melting system 

because of very low melting temperature, high affinity with oxygen, and very high 

vapor pressure of Magnesium. However, it is very easy to fabricate Fe-Mg thin films 

by sputtering. Becasue of big difference of enthalpy of Fe-O and MgO, Mg can be 

selectively oxidized in a mixture atmosphere of hydrogen and water vapor. 10 - 200 

nm thick sputtered Fe-Mg films were selectively oxidized in a damp atmosphere and 

annealed at 800-900oC for 10 - 200 min. With increasing oxidation time, saturatio 

magnetizatin of Fe-Mg films increased due to selective oxidation of Mg. Furthermore, 

Initial permeability as well as the slope of magnetizatio loops of the films decreased, 

which was attributed from the facts that morphology of the films were changed from 

continuous type to pariculated type. when the films were annealed in pure hyderogen 

atmosphere the rate of change is very slow. The reason for the expedited change is 

probably due to energy transfer to Fe atoms during migration of Mg atoms to film 

surface . 

PM21 

Optimum spacing of magnetic alloy strips in open-type magnetic 

shielding 

Yun-seog Lim, Sang-yun Lee, Ho-seong Ahn, Dong-il Lee and Sang-beom Kim* 

Korea Electric Power Corporation Research Institute, Korea 

This study suggests an effective shielding method for power frequency magnetic 

field in open-type magnetic shielding, which secures the clear view of field sources 

by aligning magnetic alloy strips sparsely. A neutral ground reactor (NGR) was used 

as a field source. The 0.35 mm thick commercial grade grain-oriented electrical steel 

(GO) and permalloy (PC) were cut into a size of 50x1200 mm2 and then placed 

vertically 600 mm away from the center of the NGR. In a weak magnetic field, PC 

was the best in shieldng performance, whereas GO was the best in a strong magnetic 

field due to change in hierachy of material permeability with increasing magnetic field 

strength. In case of multi-layered shields, it was observed that combination of GO/PC/ 

GO was more effective than the triple-layered shield of the same material. However, 

closely conjoined GO/PC/GO shield showed worse shielding performance than the 

same layered shield seperated from each other, which demonstrates it acts as one 

body regardless of presence of thin surface insulation layers. This study reports that 

introducing air gap between laminations of each layered shield is important to obtain 

desired shieding performances and optimum spacing between alloy strips exits in opentype 

magnetic shielding.

PM22 

Magnetocaloric effect in Ni 2.27Mn 0.73Ga Heusler alloy 

Mikhail Drobosyuk, Vasiliy Buchelnikov, Sergey Taskaev and Rafael Fayzullin 

Chelyabinsk state university, Russia 

Drobosyuk Mikhail, Buchelnikov Vasiliy, Taskaev Sergey, Fayzullin Rafael 

Chelyabinsk State University, Chelyabinsk, Russia m.syuk@mail.ru type of 

presentation: poster There are many theoretical and experimental works devoted 

a possibility any magnetic materials to change its temperature after applying an 

external magnetic field. This effect is called the magnetocaloric effect (MCE). 

Recent experimental studies have shown that Ni-Mn-Ga Heusler alloys have 

unique properties such as the shape memory effect, the large magnetostriction, the 

large magnetoresistance and other magnetic properties. In this work we present the 

experimental studies of the MCE for Ni 2.27Mn 0.73Ga Heusler alloy. Polycrystalline 

ingot was prepared by a conventional arc-melting method. Samples for measurements 

were cut from the middle part of the ingot. The magnetocaloric measurements were 

performed by the Magnetocaloric Measuring Setup produced by AMT&C. The results 

of measurements will be shown on the poster. 

PM23 

Soft magnetic properties of Fe-6.5wt.%Si alloy sheets fabricated by 

powder hot-rolling 

Hunju Lee 1 , Hwijun Kim 2 and Mooyoung Huh 1 * 


2 Korea Institute of Industrial Technology, Korea 

It is widely known that Fe-6.5 wt.% Si alloys have excellent soft magnetic properties. 

In this work, Fe-6.5 wt.% Si sheets were rolled by powder hot-rolling process without 

cracking and soft magnetic properties were investigated with microstructural defects. 

The cylindrical preforms were prepared by inert gas atomization and subsequent spark 

plasma sintering of Fe-6.5 wt.% Si powders at 1223K. The Fe-6.5 wt.% Si sheets were 

fabricated by hot rolling of copper canned preforms at 1173K with total reduction of 

70%, 80% and 90%, respectively. The hot rolled sheets were annealed at 1073K in an 

argon atmosphere. Microstructures and magnetic properties (magnetic flux density, 

coercivity and core loss) of the hot rolled and annealed Fe-6.5 wt.% Si sheets were 

examined by scanning electron microscopy (SEM), vibration sample magnetometer 

(VSM) and B-H analyzer. The hot rolled Fe-6.5wt.% Si sheet with reduction of 90% 

and subsequent annealing exhibited soft magnetic properties such as magnetic flux 

density of 1.8 T and coercivity of 20 A/m. This result is due to the elimination of 

microstructural defects and the increase of the average grain size and density. 

PM24 

Structure and magnetic properties of nano/micro-sized Mn-Al alloy 

powders produced by plasma arc-discharge and gas atomization 

Junggoo Lee 1 *, Younkyoung Baek 1 , Hwijun Kim 2 and Chuljin Choi 1 

1 Powder & Ceramics Division, Korea Institute of Materials Science, Korea 

2 Eco-Materials and Processing Division, Korea Institute of Industrial Technology, 

Korea 

The τ-phase in the Mn-Al system has attracted great attention due to the remarkable magnetic properties 

superior to the Alnicos and hard ferrites, low cost, as well as good machinability and corrosion resistance. 

Due to these reason, several methods have been employed to produce τ-phase Mn-Al alloy powder until 

now. On the other hand, plasma arc-discharge and gas-atomization method has been widely used for the 

production of nano-sized and micro-sized powders, respectively. To our best knowledge, however, there is 

no comparison study of Mn-Al alloy powder produced by these two methods. In the present study, Mn-Al 

alloy powders were prepared by the methods of plasma arc-discharge and gas-atomization and influence of 

process parameters on composition, particle size, and magnetic properties of the powders was systematically 

investigated. Mn-Al powder produced by plasma arc-discharge was smaller than its single magnetic domain 

and exhibited the coercivity of 5.6 kOe, which is the highest among the values reported until now. It was 

also confirmed that the magnetic properties of micro-sized powder produced by gas-atomization have been 

improved by subsequent treatments such as annealing and mechanical milling Based upon these results, the 

magnetic properties of these two types of Mn-Al alloy powders will be discussed. 

This research was supported by a grant from the Fundamental R&D Program for Core Technology of 

Materials funded by the Ministry of Knowledge Economy, Republic of Korea. 

PM25 

PM26 

PM27 


Ultra high speed pm type synchronous motor-generator with 

amorphous core for micro turbine 

Do-kwan Hong*, Yeon-ho Jeong, Dae-suk Joo, Byung-chul Woo and Dae-hyun Koo 

Electric Motor Research Center, Korea Electrotechnology Research Institute, Korea 

Temperature dependence of magnetic domains in grain-oriented 

silicon steel 

H. L. Park 1 , R. Schaefer 2 , O. Y. Kwon 3 and Y. H. Jeong 1 * 

1 Physics, POSTECH, Korea 

2 IFW Dresden, Institute for Metallic Materials,, Germany 

3 Pohang Iron and Steel Company, Korea 

WITHDRAWN 

Abstract: Silicon steels are essential for transformers and the reduction of loss in them 

is of utmost importance in this green age. Since the loss in steels are closely related 

to their magnetic domain structures, the magnetic domain structures in turn are of 

exceeding interest. We studied magnetic domains of 3% silicon steel single crystals 

with (110) [001] texture as a function of temperature via magnetooptical Kerr effect 

(MOKE) microscopy. Generally, the silicon steels (110) [001] have 180° main domains 

oriented along the [001] axis, and they also have complimentary Lancet domains in 

case of misorientation. [1, 2, 3] The MOKE images shown in Figure 1 clearly reveal 

that the domain patterns change as temperature is changed. The width of the 180° 

main domains, for instance, decreases with increasing temperature. In order to go 

one step further from mere qualitative observations, we analyzed the MOKE images 

quantitatively, and, in particular, investigated temperature dependence of the 180° 

domain width and the Lancet domain density. These temperature characteristics will be 

interpreted from the standpoint of total energy minimization. 

[1] A. Hubert, R.Schaefer, Magnetic domains(1998),Springer [2] Y. Ushigami, J. Magn. Magn. 

Mater. 254-255(2003), 307-314 [3] M. Imamura, Physica Scripta. T 24 (1988) 

A tri-layer stress impedance sensor using amorphous magnetostrictive 

thin film 

Bodong Li*, Ahmed Alfadhel and Jurgen Kosel 

KAUST, Saudi Arabia 

Mechanical stress sensors have a wide area of applications in strain and torque 

measurements. Thin film stress impedance (SI) sensors have several advantages over 

other stress sensors such as high sensitivity in small stress range, miniaturization 

possibility as well as the integration capability with other devices. Stress sensors 

that utilize amorphous magnetostrictive thin films have been proposed previously. 

The permeability change of the magnetostrictive material upon the applied external 

stress was evaluated throughout an impedance measurement. In this work, a tri-layer 

thin film stress sensor is fabricated and analyzed. The sensor has a Fe 40Ni 38Mo 4B 18/ 

Ti/ Fe 40Ni 38Mo 4B 18 tri-layer structure with 900 nm thickness each and dimensions of 

10×0.1 mm2. After the deposition, the sensor is annealed at 300 °C with a magnetic 

field of 500 Oe applied in the transverse direction to induce an in-plane transverse 

anisotropy. The magnetic behavior is studied with a vibrating sample magnetometer 

and the crystallographic structure is studied with using X-ray diffraction. The sensor 

is tested by applying compressive and tensile stresses and the sensor response was 

obtained from an impedance analyzer. The results show high sensitivity at strains 

between 0-80 ppm with a maximum impedance change of 16% at 50 MHz. 

Frommberger, M.; Glasmachers, S.; Schmutz, C.; McCord, J.; Quandt, E., IEEE Trans. Magn., vol. 

41, pp.3691 - 3693, 2005 





PM28 

Magnetoimpedance(GMI) effect in the NiFe shell/Cu core wires 

fabricated by electrodeposition 

Dong Young Kim, Sung Jae Jeon, Jung Dong Kim and Seok Soo Yoon* 

Physics, Andong National University, Korea 

Microwires with NiFe shell on Cu core of 90 μm diameter were fabricated by 

electrodeposition method. The thickness of NiFe shell was well controlled by 

deposition time in the range of 4 μm ~18 μm. Giant magnetoimpedance(GMI) effect 

in the NiFe/Cu core shell wire was measured in frequency range of 10 kHz ~ 10 MHz 

and in the magnetic field range of -300 Oe ~ 300 Oe. The variations GMI ratio with 

frequency and NiFe shell thickness were analyzed in terms of magnetic relaxation and 

skin depth at ac field. We obtained maximum GMI ratio of 250 % at 300 kHz in the 

wire with NiFe shell of 11.5 μm thickness. 

PN01 

SQUID, XRD and Raman studies of Mn implanted gallium nitride at 

elevated temperature 

N. S. Pradhan 1 , Sheshmani K. Dubey 2 , A. D. Yadav 1 , B. K. Panigrahi 3 , K. G. M. Nair 4 

and M. Roy 5 

1 

Department of Physics, University of Mumbai, Mumbai, India 

2 

Deparment of Physics, University of Mumbai, India 

3 

Materials Science Division, Indira Gandhi Centre for Atomic Research, 

Kalpakkam-603 102, India 

4 

Materials Science Division,, Indira Gandhi Centre for Atomic Research, 

Kalpakkam-603 102, India 

5 

Chemistry Devision, Bhabha Atomic Research Center, Mumbai - 400 005, India 

The magnetic and structural properties of GaN samples implanted with 325 keV Mn 2+ 

ions at 350 0C substrate temperature for various fluences varying from 1.75 x 1015 

to 2.0 x 1016 ions cm-2 were studied using SQUID, XRD and Raman scattering 

techniques. Magnetic properties were found to vary with the ion fluence.The 5 MeV 

Si + ion irradiation with fluence of 1 x 1016 ions cm-2 was performed on the sample 

implanted for ion fluence 2 x 1016 cm-2.The Curie temperature estimated for asimplanted 

and after irradiated with 5 MeV Si++ ion samples was found to 301 and 

326 K respectively. XRD spectra showed GaN peak at (002) reflection, this peak 

shifted toward lower angle indicated the incorporation of Mn ion in GaN film.Raman 

spectra of the samples showed bands at ~300 and 670 cm-1 were attributed to the local 

vibration modes of gallium and nitrogen vacancies related defects respectively. 

PN02 

Oxidation of monovacancies in graphene by oxygen 

Thaneshwor Prashad Kaloni and U. Schwingenschlögl 


We study the oxidation of monovacancies in graphene by oxygen molecules using 

first principles calculations. In particular, we address the local magnetic moments 

which develop at monovacancies and show that they remain intact when a molecule 

is adsorbed such that the dangling carbon bonds are not fully saturated. The observed 

value of magnetic moment is 1.35 Bohr Magneton for monovacancy and it becomes 

1.86 Bohr Magneton by oxygen adsorption on monovacancy in graphene. However, 

the lowest energy configuration does not maintain dangling bonds and is found to 

be semiconducting. Our data can explain the experimentally observed behavior of 

graphene under exposure to an oxygen plasma. 


PN03 

Structural , compositional and magnetic study of bulk Fe doped ZnO 

system and impurity phase formation 

Shumaila Karamat 1 *, Rajdeep Singh Rawat 2 , Paul Lee 3 , Tan Tuck Lee Augustine 4 and 

Muhammad Ghaffari 5 

1 

Physics, 1. NIE, Nanyang technological University, Singapore 2. COMSATS 

Islamabad, Pakistan, Pakistan 

2 

NSSE-NIE, Nanyang Terchnological University, Singapore, Singapore 

3 

NSSE-NIE, Nanyang Technological Unievrsity Singapore, Singapore 

4 

Physics, Nanyang Technological University, Singapore, Singapore 

5 

EEE, Nanyang Technological University, Singapore, Singapore 

Structural, compositional, optical, vibrational and magnetic properties have been studied for (ZnO) 1x(Fe 

2O 3) x≤0.10 series of bulk samples. The ZnO based ceramic samples with different doping percentage 

of Fe 2O 3 were prepared by ball milling process. The phase composition of the pellets was determined via 

X-ray diffraction analysis. Raman spectroscopy give information about the additional modes appear in the 

ZnO spectrum having Fe doping which assures the presence of Fe in the ZnO matrix. The de-convolution 

of XPS spectra of core peaks of different elements indicated the presence of different bond breakage due 

to Fe substitution in ZnO lattice. The appearance of shaking satellites in XPS spectra also confirmed the 

presence of different valance states of Fe ions. The red shift in energy band gap estimated from reflectance 

UV-VIS spectroscopy was observed for all bulk samples. The magnetic behavior of the samples was 

examined by using Vibrating Sample Magnetometer (VSM) indicating ferromagnetic behavior at room 

temperature. The effective magnetic moment per Fe atom decreases with the increase in doping percentage 

which indicates that ferromagnetic behavior is due to substitution of Fe ions in the ZnO lattice. 

PN04 

Enhanced magnetization and spin injection in Co/ZnO films by Al 

doping 

Zhiyong Quan, Wei Liu and Xiaohong Xu* 

School of Chemistry and Materials Science, shanxi normal university, China 

An important hurdle in the development of semiconductor spintronic devices is 

the inefficient injection of spin polarized currents from metallic ferromagnets 

into semiconductors due to the large conductivity mismatch. Inserting a magnetic 

semiconductor at the interface was regarded as an effectively route for spin injection 

into semiconductors. In this work, we investigate the magnetism and electrical spin 

injection into ZnO and Al-doped ZnO (Al 2at.%) matrix from Co particles in Co/ 

ZnO and Co/ZnAlO films, which were prepared by depositing ultrathin Co layers 

and semiconductor layers at room temperature. The films consist of Co particles 

dispersed in the semiconductor matrix. The graded magnetic semiconductors were 

formed at the transition region between metallic Co particles and semiconductor matrix 

with the substitution of Zn 2+ with Co 2+ ions. The increasing of magnetization of Co/ 

ZnAlO films compared to the corresponding Co/ZnO films is probably due to the 

enhanced magnetization of graded magnetic semiconductors with Al enhancing carrier 

concentration. The room temperature magnetoresistance of Co/ZnAlO film with 1.0 

nm of ZnAlO layer reaches -12.3% which is higher than -8.4% of the corresponding 

film without Al, probably due to the large spin filter effect occurring in the graded 

magnetic semiconductors having a relative lager polarization. 

PN05 

Structure, magnetic, and transport properties in Cu 1-xMn xO 

compounds 

Jinzhu Cai, Li Li, Bin Lv, Shen Wang, Wenqin Zou, Fengming Zhang* and Xiaoshan 

Wu 


By annealing at air, O 2, N 2 atmosphere, the polycrystalline Cu 1-xMn xO powders, 

which are prepared by sol-gel method with the concentration range of 0≤x≤0.2, are 

synthesized. The phase component and atomic structure of the main phase are obtained 

by X-ray diffraction (XRD) with Rietveld refinements. The bond length of Cu(Mn)-O 

decreases, and the bond-angle of Cu(Mn)-O-Cu(O) increases, with increasing the 

dopant. Magnetism measurements (SQUID) show that the ferromagnetic transition 

temperature, Tc, and the saturation moment, Ms, increase with the doped concentration 

of Mn, although all the samples show that the Tc is less than 100 K. All samples show 

the well defined thermal active mechanism with the thermal active energy varying with 

the annealing atmosphere. Results reveal that annealed in O 2 may increase the carrier 

concentration of the prepared samples while annealed in N 2 the reverse.

PN06 

A probe into the structural, magnetic and dielectric properties of 

barium and lithium substituted pseudobrookites 

Pushpinder Gupta Bhatia 1 * and Radha Srinivasan 2 

1 Physics, Department of Physics, Guru Nanak college, Mumbai-37, India 

2 Physics, Department of Physics, University of Mumbai, Mumbai-98, India 

The versatile nature of the Fe-Ti oxides makes them attractive candidates in 

applications in which their coupled semiconductor, magnetic and dielectric properties 

can be exploited and they appear to be good candidates for emerging technologies 

such as spintronics, magneto-electronics, and radar electronics. In the present work, 

pure pseudobrookite Fe 2TiO 5 and its lithium and barium substituted varieties namely 

Ba 2y Fe 2-x Li 3xTi 1-yO 5 and Ba 3x/2 Fe 2-x Li 4yTi 1-yO 5 (x = y = 0.05) are synthesized by the 

solid-state reaction method. Powder x-ray diffraction studies show the single phase 

orthorhombic structure. Substitution has reduced the crystallite size but enhanced the 

grain size. A new intense plane (122) is observed in the barium-substituted sample. 

Lithium intercalation is also observed. Room temperature dielectric studies have 

confirmed the Maxwell- Wagner interfacial polarization and space charge is seen to 

have almost doubled with doping. The magnetic hysteresis loops show an asymmetric 

shift and constriction of loops. Variation of normalised susceptibility with absolute 

temperature is plotted. Presence of barium and lithium have also brought about a long 

range magnetic ordering in the pseudobrookite. Susceptibility measurements also 

show that the Curie temperature in the barium-rich pseudobrookite approaches room 

temperature making it a potential switch material. 

PN07 

Oxygen vacancy and magnetism of a room temperature ferromagnet 

Co-doped TiO2 Ikuo Nakai 1 *, Masashi Sasano 1 , Yingjie Li 2 , Ken Inui 1 , Tomoya Korekawa 1 , Hiroyuki 

Ishijima 1 , Hisashi Katoh 1 and Makio Kurisu 3 

1 

Department of Electrical and Electronic Engineering, Graduate School of 

Engineering, Tottori University, Japan 

2 

Inner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials, 

Inner Mongolia Normal University, China 

3 

Department of Physics, Graduate School of Science and Engineering, Ehime 


We report the magnetic and local structural study of a room temperature ferromagnetic 

Co-doped TiO 2 prepared by the solid state reaction. The ferromagnet with 5% Co 

shows a rutile-type structure and has a saturation magnetization of 0.005 JT-1kg-1 

and a coercive force of 0.02 T. We have found that it has some oxygen vacancy sites 

around a Co atom only from the extended x-ray absorption fine structure (EXAFS) 

measurement. The charge compensation makes the oxygen vacancy around Co 2+ and/ 

or Co 3+ substituted with Ti 4+ . 

PN08 

Effect of annealing on the magnetic anisotropy of GaMnAs film with 

low Mn concentration 

Hyehyeon Byeon 1 , Yoonjung Gwon 1 , Jaehyuk Won 1 , Taehee Yoo 1 , Sanghoon Lee 1 *, X. 

Liu 2 and J. K. Furdyna 2 

1 Physics Department, Korea University, Korea 

2 Physics Department, University of Notre Dame, USA 

We have investigated the effect of annealing on the magnetic anisotropy of a GaMnAs 

film with a low Mn composition of 2 %. Three pieces of samples were cleaved from 

the sample and two of them we are annealed at 200 and 300 °C, respectively, for 

3 hours in air. In case of as-grown sample, abrupt transitions in the Hall resistance 

appeared with a negative coercive field, when field strength was swept at a fixed 

direction in the film plan. The phenomenon turned out to be related to the presence of 

magnetic domains with a vertical easy axis in the film, which was identified via the 

Hall measurement that was performed with a field direction that was normal to the 

plane. The portion of domain with dominant out-of-plane magnetic anisotropy in the 

GaMnAs film was systematically decreased with an increasing annealing temperature. 

Especially, the negative coercive field disappeared in the sample annealed at 300 °C 

and two abrupt positive switching fields we are observed in the field scan of the planar 

Hall resistance. This indicates that the annealing significantly affects the magnetic 

anisotropy of GaMnAs film by changing from out-of-plane dominant to in-plane 

dominant anisotropy. 

PN09 

PN10 

PN11 


Low field magnetization reversal behavior of ferromagnetic GaMnAs 

film 

Yoonjung Gwon 1 , Hyehyeon Byeon 1 , Jaehyuk Won 1 , Hakjoon Lee 1 , Sanghoon Lee 1 *, 

X. Liu 2 and J. K. Furdyna 2 



We have investigated magnetization reversal process of a GaMnAs film by using 

planar Hall effect. The angle-dependent measurements of the planar Hall resistance 

(PHR) showed sinusoidal behavior without hysteresis between clockwise and counter 

clockwise rotation with strong field. However, the magnetization reversal behavior 

changes significantly by showing abrupt transition at the directions as the field 

strength reduced to 200 Oe. Furthermore, when a smaller field is used, the PHR displays 

four stable values arising from the formation of four different multidomain states during 

the rotation of the external field direction over 360°. Two of these states, showing 

maximum and minimum values of the PHR, correspond to the sample fully magnetized 

along one of the easy axes. Other two intermediate states are multi-domain states in 

which a fraction of the domains populates one easy [100] direction, and the remaining 

fraction populates an orthogonal easy [010] direction. We showed that the relative 

populations of the magnetic domains corresponding to the two orthogonal easy axes 

can be controlled by the value of the applied field during the process of magnetization 

reversal. This phenomenon was understood by considering the differences in domainpinning 

fields and their distributions required for crossing the two hard axes. 

Half-metallic antiferromagnetism in the ordered Cr 1-xCa xSb alloy from 

first-principles calculations 

Guoying Gao* and Kailun Yao 

School of Physics, Huazhong University of Science and Technology, China 

Compared to half-metallic ferromagnets, half-metallic antiferromagnets (precisely 

called half-metallic fully compensated ferrimagnets) are more promising candidates 

for spintronic applications since their zero magnetization leads to lower stray fields and 

thus tiny energy losses. Using the first-principles calculations, we have systematically 

investigated the electronic and magnetic properties of the ordered Cr 1-xCa xSb alloy. 

It is found that Cr 1-xCa xSb with x = 0.125, 0.25, 0.5 and 0.75 all are half-metals like 

zinc-blende CrSb and CaSb which have been fabricated experimentally or predicted 

theoretically. Interestingly, Cr 0.25Ca 0.75Sb is a half-metallic antiferromagnet with 

complete spin polarization, and the half-metallic antiferromagnetism is robust against 

the lattice compression and expansion and the choice of electronic exchange and 

correlation functional. 

[1] H. Akai, M. Ogura, Phys. Rev. Lett. 97, 026401 (2006). [2] B.-G. Liu, Phys. Rev. B 67, 172411 

(2003). [3] M. Sieberer, et al., Phys. Rev. B 73, 024404 (2006). [4] G.Y. Gao, et al., Phys. Rev. B 75, 

174442 (2007); [5] J.H. Zhao, et al., Appl. Phys. Lett. 79, 2776 (2001). [6] G. Y. Gao, J. Chen, and 

K.L. Yao, Phys. Lett. A 375, 4053 (2011). 

Translation & rotation of diamagnetic material induced by a low field 

of a permanent magnet and terminal identification of a micron-sized 

particle 

Keiji Hisayoshi and Chiaki Uyeda 

Osaka university, Japan 

It has been generally believed that field-induced motion of an ordinary diamagnetic 

material can be induced only at high field above several Tesla. However, translations 

were recently observed on various diamagnetic crystals in a direction of monotonously 

decreasing field produced by a permanent magnet [1]; the crystals were released in 

diffused micro-gravity area. In a given field distribution, terminal velocity of translation 

is uniquely determined by intrinsic susceptibility of material; the velocity is independent 

to mass of particle. Rotational oscillation, caused by diamagnetic anisotropy energy, was 

also reported for the crystals [1]. When the above motions are observable, diamagnetic 

susceptibility & anisotropy of a small particle can be detected, irrespective of its size, 

since the measurements are both free from interference of a sample holder and from 

mass measurement of sample. Material identification of particle is easily performed 

by comparing the obtained susceptibility (& anisotropy) with published values. A 

simple and nondestructive method to identify the material of a small particle is desired 

in various fields of nano-science. By introducing a compact NdFeB magnet, the 

measurement was realized in an ordinary laboratory using a chamber-type drop shaft. 

[1] C. Uyeda et al: Jpn. Phys. Soc. Jpn. 79, 064709 (2010). 246 




PN12 


Magnetoresistance effect in electron-injected p-type silicon 

Michael P. Delmo*, Eiji Shikoh, Teruya Shinjo and Masashi Shiraishi 


Magnetoresistance (MR) effect in silicon has gained a renewed interest in recent 

years because it is large and non-saturating [1-3]. It is known that the presence of 

“static” inhomogeneity, like phosphorus in low-doped silicon, generates large and 

non-saturating MR effect [2,4]. Inhomogeneity can also be introduced “dynamically” 

by injecting electrons or holes into a low-doped silicon [1,3]. In n-type silicon (n-Si), 

electron injection generates space-charge effect [1], whereas, the hole injection induces 

the formation of a hole-electron (p-n) boundary [3]. These dynamic inhomogeneities 

induce large MR effect even up to room temperature. Most of the silicon devices used 

in inhomogeneity-induced MR effect studies are n-type, and no study has ever been 

reported for p-type, so far. In this study, we investigated the MR effect in indium (In)/ 

p-type silicon (p-Si)/In devices. Current (I)-voltage (V) characteristic of the device 

shows an Ohmic and non-Ohmic I-V regime (I is proportional to the square root of 

V), which indicates electron space-charge injection into p-type silicon [5]. MR of the 

In/p-Si/In device is small (10%) compared to that of In/n-Si/In device (1,000%) for 

the same condition (3 T, 300 K). This suggests that the electron-hole compensation or 

recombination suppress inhomogeneity formation in the silicon device. 

[1] Delmo, M.P. et al. Nature 457, 1112 (2009). [2] Porter, N.A. & Marrows, C.H., arXiv:1105.2174 

[cond-mat.mtrl-sci]. [3] Wan, Caihua et al. Nature 477, 304 (2011). [4] Herring, C. J. Appl. Phys. 

31, 1939 (1960). [5] Roberts, G.G. Phys. Stat. Sol. 27, 209 (1968). 

PN13 

First-principles investigation of the influence of adsorbed atom on the 

defect and impurity substitute graphene 

Kengo Nakada 1 and Akira Ishii 2 

1 JST-CREST, Japan 

2 Department of Applied Mathematics and Physics, Tottori University, Japan 

Graphene is well-known to be two-dimensional material made of carbon atoms. 

Graphene is a substance that attracts attention not only as parts of the nanocarbons 

but also for its own interesting electronic and mechanic properties. It is important 

for the application that charge and magnetic are controlled by defect and impurity 

in the graphene. Furthermore, influence of defect and the impurity are important in 

the growth of the compound on the graphene. The technological uses of controllable 

charge and magnetic carbon systems are extensive, and it is important that the 

mechanism is known. In previous study, we investigated the adsorption energies and 

magnetism in adsorption sites on graphene from atomic number 1 to 83, using the 

DFT. We discussed the charge transfer and the magnetism. When several adatoms is 

adsorbed, the defect graphene develops magnetic. In this study, we performed atom 

substitute in the graphene and atomic adsorption on the graphene with the defect. The 

aim of the research is discussion about the magnetic and stability when several adatoms 

adsorbed on defects and impurities substitue in graphene. In addition, we discuss the 

growth mechanism of the nitrided compounds. We used a band calculation technique 

based on the DFT calculation. 

PN14 

Room-temperature fabrication of highly transparent magnetic 

nanocomposite systems by aerosol deposition 

Jae-hyuk Park* and Akedo Jun 

National Institute of Advanced Industrial Science and Technology (AIST), Japan 

Nanocomposite systems, materials containing particles of nanometer dimensions have shown 

interesting properties related to its extremely small size. Some of their optical, magnetic, electronic, 

mechanical, and chemical properties are different from those exhibited by the same composition in 

bulk material[1]. We have proposed novel concept for materializing nanoocmposite systems using 

aerosol deposition (AD) process[2-3]. Our concept can apply various sizes of nanoparticles, and 

achieves desirable distribution of nanoparticles in host matrix because the structure of deposited 

layer is similar to that of composite powder. In this report, we developed highly transparent 

magnetic nanocomposite thick films consisting of cobalt nanoparticles embedded in a host matrix 

of ferroelectric lead zirconate titanate (PZT) by AD process at room temperature. Transparent 

thick nanocomposite cobalt/PZT films display very dense without any pores as well as any cracks. 

As the wt% of nanocobalt increased, magneto-optic effect measured in the transmission mode, 

especially Faraday rotation effect of nanocomposite layers gradually increases with good linearity. 

The 0.1 wt% nanocobalt -containing nanocomposite film acquired the Faraday rotation angle of 

approximately 0.2 degree. These results would strongly show potential of optical multiferroics on 

transparent nanocomposite systems. 

[1] M. Abe, M Gomi, and F. Yokoyama, J. Appl. Phys., Vol. 57, pp. 3909-3911, 1985. [2]J. Akedo, 

J. Am. Ceram. Soc., Vol. 89, pp. 1834-1839, 2006. [3] Jae-Hyuk Park, Jun Akedo and Masafumi 

Nakada, Jpn. J. Appl. Phys., Vol.45, pp. 7512-7515, 2006 


PN15 

Effect of transition metal (Co, Ni and Cu) doping on lattice volume, 

band gap, morphology and saturation magnetization of ZnO 

nanostructures 

Faheem Ahmed, Shalendra Kumar, Nishat Arshi, M S Anwar and Bon Heun Koo* 

Changwon National University, Korea 

The interest in transition-metal (TM)-doped ZnO has increased because of promising 

applications in the field of semiconductor spintronics, which seeks to extend the 

properties and applications of established electronic devices by using the spin of 

electrons in addition to their charge. In this work, the effect of different TM (Co, Ni 

and Cu) doping on structural, optical and magnetic properties of ZnO nanostructures 

have been studied. Zn 1-xTM xO (TM=Co, Ni and Cu) nanostructures were prepared by a 

microwave assisted chemical route and characterized by X-ray diffraction (XRD), field 

emission scanning electron microscopy (FESEM), transmission electron microscopy 

(TEM), Raman spectroscopy, UV-Vis and magnetization measurements. The X-ray 

diffraction (XRD) and TEM analysis showed that the TM-doped nanostructures had 

single phase nature with the wurtzite structure. There is a strong correlation between 

changes in the lattice parameters, bandgap energy, morphology and the saturation 

magnetization of Zn 1-xTM xO nanostrutures. Lattice volume and bandgap determined 

from XRD and UV-Vis, respectively, were found to decrease as the atomic number 

of the dopant moved away from Co. Magnetic studies showed that all the TM-doped 

ZnO exhibit room temperature ferromagnetism and the decreasing trend of saturation 

magnetization was observed with the increase of 3d electrons number from Co to Cu. 

PN16 

Functionalized graphene as a room-temperature ferromagnetic 

semiconductor 

Jeongmin Hong 1 *, Sandip Niyogi 2 , Elena Bekyarova 2 , Mikhail E. Itkis 2 , Palanisamy Ramesh 2 , 

Claire Berger 3 , Walt A. Deheer 4 , Robert C. Haddon 2 and Sakhrat Khizroev 5 

1 Electrical and Computer Engineering, Florida <strong>International</strong> University, USA 

2 Department of Chemistry, Department of Chemical Engineering, Center for Nano Scale Science 

and Eng, University of California-Riverside, USA 

3 CNRS, Institut Neel, France 

4 School of Physics, Georgia Institute of Technology, USA 

5 Department of Electrical and Computer Engineering, Florida <strong>International</strong> University, USA 

Low-temperature magneto-transport and vibrating sample magnetometry (VSM) combined with superconducting 

quantum interference device (SQUID) measurements indicated that graphene, when functionalized with aryl 

radicals, behaved as a room-temperature ferromagnet and therefore might form the basis for a new approach to 

semiconducting ferromagnetism. After radical functionalization, epitaxially grown graphene samples became 

semiconductors and at the same time displayed high-density magnetism, with a room temperature saturation 

magnetization of approximately 0.1 Bohr magnetons per carbon atom. The bulk measurements with VSM and 

SQUID were corroborated with local studies using atomic force microscopy (AFM), electrostatic force microscopy 

(EFM), magnetic force microscopy (MFM), scanning tunneling microscoy (STM), and Raman Spectra 

measurements. Both local and bulk measurements indicated a strong dependence on the degree of coverage of the 

graphene surface with functionalized sites. The measurements showed the presence of a superparamagnetic order 

in the graphene regions with a relatively low-density of functionalized sites in the entire temperature range from 2 to 

300 K. In contrast, the regions with a relatively high-density of functionalized sites displayed a ferromagnetic order 

even at room temperature. In summary, the measurements indicated that aryl radical functionalied multi-layered 

graphene on Silicon Carbide could simultaneously be a semiconductor and a ferromagnet at room temperature. 

PN17 

Tuning of the curie temperature by varying reduction potential in 

electrochemically prepared thin films of Prussian blue analogue based 

molecular magnets 

Pramod Bhatt*, M. D. Mukadam and S. M. Yusuf 

Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India 

The quest for molecular magnets with ordering temperature at or above room 

temperature is highly desirable for their practical applications at ambient conditions. 

In order to increase the ordering temperatures, many efforts have been devoted 

to synthesizing compounds with appropriate choice of organic/inorganic ligands, 

their valence modulation and spin centers, and alkali metal ion doping, etc., using 

organometallic and/or coordination chemical methods. However, we have shown 

that, the magnetic ordering temperature in PBAs (Prussian blue analogues) can be 

enhanced by varying reduction potential in electrodeposition method. In this regard, 

the electrochemically prepared films of PBAs, XjFeIIk[CrIII(CN)6]l.mH2O with 

varying reduction potential are investigated using dc magnetization measurements. The 

magnetization data for film deposited at lower reduction voltage shows ferromagnetic 

ordering with TC (Curie temperature) of ~ 21 K, similar to previously reported 

ordering temperature for this compound. However, an increase in TC up to ~50 K has 

been observed for film deposited at higher reduction potential. The observed variation 

in TC is mainly attributed to the inclusion of potassium ion (K+) at higher reduction 

potential, which changes stoichiometry of the film. The ability of tuning TC just by 

changing reduction potential could be useful for designing future device applications.

PN18 

Evolution of multifunctional behavior in site specific cation substituted 

Na 0.5Bi 0.45Gd 0.05Ti 0.95Mn 0.05O 3 ceramics 

T Karthik 1,2 and Saket Asthana 1 * 

1 Advanced Functional Materials Laboratory, Department of Physics, 

Indian Institute of Technology Hyderabad, Andhra Pradesh - 502205, India 

2 Department of Materials Science and Engineering, 

Indian Institute of Technology Hyderabad, Andhra Pradesh - 502205, India 

A novel multifunctional behavior was observed by site specific cation substitution in 

NBT ceramics prepared by conventional solid state reaction technique. X-ray diffraction 

studies revealed the co-existence of orthorhombic reflections in co-substituted NBT 

system along with the primary R3c phase. Raman spectroscopy of NBT-GM ceramics 

reveals a substantial change in all phonon modes in terms of suppression and shift 

indicates that the substitution affects nature of the cation displacement, octahedral tilt 

and hybridization. Reduced polarization value in NBT-GM ceramics with non-saturated 

hysteresis loops gives evidence for the suppression of ferroelectricity. Temperature 

dependent magnetization measurements from R.T to 2.5K in NBT-GM ceramics show 

the occurrence of spin-paramagnetic behavior. Susceptibility plots show some evidence 

for weak interaction between Mn 4+ ions at low temperatures below 30K. UV-Vis 

spectroscopy measurements reveal the indirect transition allowed band gap nature for 

both NBT and NBT-GM ceramics with a slight increase in band gap (E g) value for NBT- 

GM ceramics. Photoluminescence measurements show a strong blue emission at ~390nm 

(3.18 eV) in Gd-Mn substituted NBT system, which corresponds to radiative transition 

from 4 T 1g → 4 A 2g energy levels of Mn 4+ -ions. 

PN19 

Magnetic doping effect on physical properties of PbPdO 2 

Kyujoon Lee, Seongmin Choo and Myung-hwa Jung* 

Sogang University, Korea 

The exotic features of gapless semiconductors have attracted many researchers in solid 

state physics. Materials such as HgCdTe have been studied as a gapless semiconductor. 

Recently PbPdO 2 has been theoretically proposed to be a gapless semiconductor. 

In addition, by substituting Co for Pd ions the material becomes a spin gapless 

semiconductor which has full spin polarization. In this study we have experimentally 

shown the changes in the physical properties of PbPdO 2 by doping different magnetic 

ions such as Co, Mn, and Zn. PbPdO 2 shows a metal-insulator-like transition at 

TMI=100 K in the resistivity vs. temperature measurements. The magnetic properties 

show a diamagnetic behavior at high temperatures and a ferromagnetic behavior at 

low temperatures. The TMI increases to 150 K by Co doping and the diamagnetic 

behavior changes to paramagnetic behavior. By Mn doping, the TMI decreases 

to 73 K and the magnetic behavior changes drastically to show antiferromagnetic 

ordering at low temperatures. However no difference has been found by Zn doping. 

The common feature for all materials is that the charge carrier density increases with 

doping. The easily tuned properties of PbPdO 2 show evidence that PbPdO 2 is a gapless 

semiconductor and could be tuned to be a spin gapless semiconductor. 

PN20 

An experimental approach using EPR and XMCD to explore hydrogen 

mediated ferromagnetism 

Seunghun Lee 1 , Bun-su Kim 1 , Yong Nam Choi 2 , Naoki Ishimatsu 3 , Masahiro Sawada 3 , 

Won-kyung Kim 1 , Ji Hun Park 1 , Yong Chan Cho 1 and Se-young Jeong 1 * 

1 Cogno-Mechatronics Engineering, Pusan National University, Korea 



Since the ferromagnetism of III-VI based DMS materials such as GaMnAs was turned out to be based 

on carrier induced model, much progress has been made in developing its applicability but low operation 

temperature has limited the approach to functional devices[1]. Among other materials, Co doped ZnO has 

been regarded as strong candidate for room temperature DMS but the origin of ferromagnetism has been on 

controversy[2]. Previously, we reported experimental results on Co-H-Co responsible for ferromagnetism 

depending on hydrogen contents and position[3-5]. Here, in order to apply these phenomena for new 

functional devices, more convincing experimental evidence for Co-H-Co is necessary. In this study, we 

show the experimental approaches to hydrogen mediated ferromagnetic spin ordering in ZnCoO through 

electron paramagnetic resonance(EPR) and x-ray magnetic circular dichroism(XMCD). The signal intensity 

of ferromagnetic resonance is attributed to hydrogen contents and spin/angular magnetic moments compared 

with theoretical model of Co-H-Co are calculated from XMCD spectrum. In addition, the results of 

photoluminescence and spectrum of magnetic circular dichroism within UV-Vis range suggests the possibility 

for creating and manipulating spin-polarized carrier using hydrogenated ZnCoO. Through advanced theoretical 

calculation for Co-H-Co model, we are expecting to obtain the direct evidence for Co-H-Co unit. 

[1] D. A. Allwood et al., Science, 309, 1688 (2005) [2] S. Lee et al., Appl. Phys. Lett. 94, 212507 (2009) [3] Y. C. Cho et al., Appl. 

Phys. Lett. 95, 172504 (2009) [4] S. J. Kim et al., Phys. Rev. B 81, 212408 (2009) [5] S. Lee et al., J. Appl. Phys. (in press, 2012) 

PN21 

PN22 

PN23 


A role of mobility in hydrogen mediated ferromagnetism of ZnCoO 

Ji Hun Park 1 , Seunghun Lee 1 , Won-kyung Kim 1 , Jong Moon Shin 2 , Yong Chan Cho 1 , 

Chae Ryong Cho 2 , Hideomi Koinuma 1 and Se-young Jeong 1 * 

1 Dept. of Cogno-Mecatronics Engineering, Pusan National University, Korea 

2 Dept. of Nano Fusion Technology, Pusan National University, Korea 

Diluted magnetic semiconductors (DMSs) have recently been attracting much attention for 

their potential as spin manipulation layers [1]. Although there have been reported several 

authorized DMSs, such as Mn doped GaAs, their limited operating temperature requires new 

DMS materials with high Curie temperature. Up to now, many theoretical and experimental 

studies about hydrogen mediated ferromagnetism in ZnCoO have been introduced [2- 

3]; however, the interaction between such magnetic units as Co-H-Co complexes has not 

yet been confirmed. Delocalized electron in ZnCoO lattice is possibly considered to play 

a crucial role in the correlation [4]. In this work, we investigated the correlation between 

carrier mobility and ferromagnetic spin ordering in ZnCoO. Electron mobility was artificially 

controlled with the manipulation of crystallinity and hydrogen contents. Hydrogen treatment 

is carried out using hot isostatic pressing (HIP) system. The correlation between carrier 

mobility and ferromagnetic spin ordering was analyzed in terms of Co-H-Co magnetic units. 

Mobility-dependent ferromagnetic spin ordering is discussed in our experiment. 

[1] H. Ohno, Science, 281, 951 (1998). [2] C. H. Park and D. J. Chadi, Phys. Rev. Lett. 94, 127204 

(2005). [3] S. Lee et al., Appl. Phys. Lett. 94, 212507 (2009); Y. C. Cho et al., Appl. Phys. Lett. 95, 

172514 (2009); S. J. Kim et al., Phys. Rev. B 81, 212408 (2010). [4] Z. Lu et al., Appl. Phys. Lett. 

94, 152507 (2009). 

Magnetic and magneto-optical properties of TiO2:V semiconductor 

oxide films with various resistivity 

Andrey F Orlov 1 , Leonid A Balagurov 1 , Ivan V Kulemanov 1 , Elena A Petrova 1 , Nikolai Perov 2 *, Elena 

A Gan'shina 2 , Leonid Yu Fetisov 2 , Anna S Semisalova 2 , Anastasia D Rubacheva 2 , Andrey Rogalev 3 , 

Alevtina G Smekhova 4 and Lada V Yashina 2 

1 

Institute for Rare Metals, Moscow, 119017, Russian Federation, Russia 

2 

Lomonosov Moscow State University, Russia 

3 

European Synchrotron Radiation Facility, Grenoble Cedex, France 

4 

European Synchrotron Radiation Facility, Grenoble Cedex, France; Lomonosov Moscow State University, Russia 

We present the investigation results of semiconducting films TiO2:V with 3-18%at. of vanadium, which 

develop our previous research of doped titanium oxide [1,2]. The films have been grown by RF magnetron 

sputtering on either LaAlO3 or rutile TiO2 substrates and revealed the room temperature ferromagnetic 

ordering in the wide range of resistivity (10-3-106 Ω•cm). For degenerate semiconductors the values of 

magnetization were found to be lower. Magnetization of TiO2 doped with vanadium is maximum for all 

semiconductor oxides doped with transition metal impurities. Maximum values of magnetization were 

observed in the films with a small content of V impurity and corresponded to 4.8 Bohr magneton per V atom. 

The V impurity was found to be utterly in the oxidized state only in the films with a small V concentration. 

The magneto-optical response in the 1.5-3.0 eV energy range was observed in samples with a high magnetic 

moment only. The results are discussed within the model of charge-transfer ferromagnetism suggested by 

Coey et al. [3,4]. Supported by RFBR and Ministry of Science and Education No.16.513.11.3088. 

[1] A.F. Orlov et al., JMMM, 320, 895 (2008); [2] E.A. Gan’shina et al., JMMM, 321, 723 (2009); [3] J.M.D. Coey et al., J. Phys. D: Appl. Phys., 

41, 134012 (2008); [4] J.M.D. Coey et al., New J. Phys., 12, 053025 (2010). 

Magnetic properties and electrical conductivity on oxygen-deficient 

europium monoxide 

Jun-young Kim 1 *, Pedro M.d.s. Monteiro 1 , Kiyoung Lee 1 , Adrian Ionescu 1 , Stuart N Holmes 2 , Crispin H.w. 

Barnes 1 , Peter J Baker 3 , Sean Langridge 3 , Zaher Salman 4 , Andreas Suter 4 and Thomas Prokscha 4 

1 

Department of Physics, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, 

CB3 0HE, United Kingdom 

2 

Toshiba Cambridge Research Laboratory, 208 Cambridge Science Park, Milton Road, Cambridge, CB4 

OGZ, United Kingdom 

3 

ISIS, Harwell Science and Innovation Campus, STFC, Oxon OX11 0QX, United Kingdom 

4 

Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland 

Pristine europium monoxide (EuO) is a ferromagnetic semiconductor with a Curie temperature (Tc) of 70 

K. Below Tc, the conduction band is 100% spin-polarised [1] while at Tc it undergoes a metal-to-insulator 

transition [2]. These properties render it a promising material for future spintronic devices such as spin injection 

electrodes or filters [3]. Tunable control of magnetic properties is obtained by doping with oxygen vacancies. 

We present results on co-sputtered EuO 1-x films with Tc as high as 140 K. The films were characterized by 

SQUID magnetometry, x-ray and polarized neutron reflectometry. The magnetic moment was found to increase 

monotonically with oxygen vacancy concentration. Density-functional theory calculations of EuO 1-x show 

that oxygen vacancies act as n-type dopants and that the excess electrons preferentially populate the majority 

spin branch of the conduction band [4]. We also present thickness-dependent magnetic properties of EuO 1-x 

thin films, where surface-induced changes were observed in films with below 5 nm thickness [5]. Muon 

spin rotation measurements investigated microscopic magnetic behaviour and magnetic volume fraction as a 

function of temperature. Electrical transport measurements in the Hall geometry will also be presented. 

[1] R. P. Panguluri, T. S. Santos, E. Negusse, J. Dvorak, Y. Idzerda, J. S. Moodera, and B. Nadgorny, Phys. Rev. B 78, 125307 (2008) 

[2] G. Petrich, S. von Molnar, and T. Penney, Phys. Rev. Lett. 26, 885 - 888 (1971) [3] A. Schmehl et al., Nature Materials 6, 882 - 

887 (2007) [4] M. Barbagallo et al., Phys. Rev. B 81, 235216 (2010) [5] M. Barbagallo et al., Phys. Rev. B 84, 075219 (2011) 




PN24 


Magnetism and optical properties of diluted magnetic semiconductor 

superlattice GaGdAs/GaAs with GaGdAs nanograins 

Miyagawa Hayato*, Yuuki Uda, Shoutaro Matsumoto, Nakaba Funaki and Shyun 

Koshiba 

Faculty of Engineering, Kagawa University, Japan 

We found ferromagnetic coupling in the rare earth elements Gd doped GaAs DMS, 

abbreviated as GaGdAs, which was grown by molecular beam epitaxy (MBE). 

However, GaGdAs is easy to have distortions or dislocations, because the atomic size 

of Gd is large compared to GaAs matrix, and also there is lattice mismatch between 

GaGdAs layer and substrate. Superlattice (SL) structure of GaGdAs/GaAs, in which 

GaGdAs layers are interleaved with a few ML thick GaAs layer, is considered to 

have a good crystallinity. We fabricate magnetic semiconductor superlattice GaGdAs/ 

GaAs and mono layer GaGdAs by MBE and analyze the crystal structure by means of 

Transmission Electron Microscopy (TEM) and measured the macroscopic magnetic 

properties by Alternating Gradient Magnetometer (AGM). In high resolution TEM 

images, there are GaGdAs grains of 2-3 nm, which has high Gd concentration and 

lattice-matching in GaAs Matrix. The result of magnetic measurements shows that 

superlattice structures have larger saturated magnetization and smaller coercive field 

than that of monolayers. We think that the GaGdAs grains, which are observed only 

in SL structures, possibly has main contribution to generate ferromagnetism in room 

temperature. We also measured Photoluminescence of GaGdAs samples and found the 

energy band gap is larger than GaAs. 

PN25 

Ferromagnetism in hydrogenated fullerene 

Kyu Won Lee, Gi-wan Jeon and Cheol Eui Lee* 

Physics, Korea University, Korea 

We identify Stoner ferromagnetism in fcc C 60Hn (n=odd) by using a local density 

approximation in the framework of the density functional theory. Hydrogen 

chemisorption on fullerenes creates quasilocalized π-electrons on the fullerene surface, 

overlapping of their wave functions giving rise to a narrow half filled impurity band in 

the fcc C 60Hn. The Stoner-type ferromagnetic exchange between the itinerant electrons 

leads to spin-split impurity bands. The magnetic moment per C 60Hn molecule is 1 μB 

(for n=odd) or 0 (for n=even, including zero), only one of the hydrogens contributing 

to the spin-split states. Direct overlapping of the quasilocalized π-electron orbitals is 

essential for the ferromagnetism. 

1. T. L. Makarova, B. Sundqvist, R. Ho¨hne, P. Esquinazi, Y. Kopelevich, P. Scharff, V. A. Davydov, 

L. S. Kashevarova, and A.V. Rakhmanina, Nature (London) 413, 716 (2001). 2. T. L. Makarova, B. 

Sundqvist, R. Ho¨hne, P. Esquinazi, Y. Kopelevich, P. Scharff, V. Davydov, L. S. Kashevarova, and 

A.V. Rakhmanina, Nature (London) 440, 707 (2006). 3. S. Okada and A. Oshiyama, Phys. Rev. B 68, 

235402 (2003). 

PN26 

Enhancement of the magneto-optical effect by an addition of Co in 

pseudo-quaternary II-VI magnetic semiconductor CdMnCoTe films 

Masaaki Imamura* and Keisuke Ninomiya 

Electrical Engineering, Fukuoka Institute of Technology, Japan 

Magneto-optical properties with pseudo-quaternary magnetic semiconductor 

CdMnCoTe films deposited on quartz glass substrates by using MBE equipment [1] 

have been studied at a visible wavelength region at room temperature. Deposition 

was made at an average rate of ~1 Å/sec for 8h using a 4N Co target sputtered by an 

electron gun having an emission-current of 20 mA, a 5N CdTe effusion cell heated at 

490˚C and a 4N MnTe cell at 1020˚C. Using this system, ~2-μm-thick CdMnTe and 

CdMnCoTe films were prepared on 0.5-mm-thick QG substrates. These films exhibited 

the preferred (111) growth and paramagnetic characteristics. The magnetization 

intensity at 15 kOe at room temperature was approximately 2.5x10-4 emu for the 

Cd 0.65Mn 0.35Te film and 2.8x10-4 emu for the Cd 0.56Mn 0.39Co 0.05Te film, showing the 

values that were almost the same for two films. Faraday rotation measured at 620 nm 

in the CdMnCoTe film was -0.32 deg/cm-G and that in the CdMnTe film was -0.10 

deg/cm-G. Thus the Faraday rotation in the CdMnCoTe films was largely enhanced 

compared to that in the CdMnTe films. A direct ac Faraday rotation observation under 

1.27 kHz ac fields generated by a ring magnet [2] has successfully been carried out for 

the CdMnCoTe films. 

[1] A. Okada et al., IEEE Trans. Magn. 39, 3175 (2003). [2] A. Okada et al., J.Magn. Soc. Jpn., 31, 

328 (2007). 


PN27 

Origin of ferromagnetism in Co-doped (La,Sr)TiO 3 diluted magnetic 

semiconductors 

Xuefeng Wang 1 , Fengqi Song 2 , Yi Shi 1 , Rong Zhang 1 and Jianbin Xu 3 

1 School of Electronic Science and Engineering, Nanjing University, China 

2 Department of Physics, Nanjing University, China 

3 Department of Electronic Engineering, The Chinese University of Hong Kong, 

China 

Diluted magnetic semiconductors (DMSs) are one of the important supporting materials 

for the new-generation of spintronic devices. We prepared (La,Sr)TiO 3 (LSTO) and Codoped 

LSTO DMS nanocrystals through solvothemal technique combined with postannealing 

process. After that, the effects of concentration of Co dopant, the annealing 

atmosphere, temperature, duration and other conditions on the microstructures and 

magnetic properties were investigated. When the doping concentration is lower than 

5 at.%, the observed room-temperature ferromagnetism (RTFM) of our samples is 

of intrinsic property. Meantime, it is found that the magnetism has the close relation 

with the concentration of Co dopant and the amorphous carbon which is remained 

after annealing. Through controlling the annealing atmosphere and duration, we can 

synthesize single-phase Co-doped LSTO nanocrystals. It is demonstrated that the RTFM 

is correlated with the structural defects induced in the Ar annealing process. It is also 

shown that Co-doped LSTO nanocrystals will have the CoO secondary phase when the 

Co doping concentration is higher than 5 at.%. According to the interesting exchange 

biasing phenomenon, the RTFM of our samples is ascribed to the collection of the CoO 

nanophase or amorphous Co metallic impurities. 

PN28 

Two dimensional growth of Nb doped SrTiO 3 thin films and its 

superlattices 

Abhijit Biswas, Yong Woo Lee, Min Hwa Jung and Yoon Hee Jeong* 

Department of Physics, Pohang University of Science and Technology, Korea 

Two dimensional growth modes were obtained for Nb doped SrTiO 3 thin films grown 

on TiO 2 terminated SrTiO 3 (001) substrates; as monitored by in-situ reflection highenergy 

electron diffraction (RHEED). At low substrate temperature ordinary RHEED 

oscillation was observed, indicating layer by layer growth. At high temperature, 

recovery of RHEED intensity after switching off laser pulses indicated the step flow 

growth mode. In both cases, films show metallic behavior with resistivity (ρ)~10-3 

Ω-cm. Nb:SrTiO 3/SrTiO 3 (NSTOm/STOn) superlattices were also being fabricated 

at low temperature containing five unit cell thick NSTO layers with various stacking 

sequences. Film surfaces were characterized by atomic force microscopy (AFM), 

showing high crystalline quality having steps of 3.9 A. At room temperature, resistivity 

was found to be 1~2 Ω-cm. The oxide superlattice growth approach might provide a 

useful way to control the charge carrier and resistivity for novel device applications. 

PN29 

Anomalous hall effect in ferromagnetic nanocomposite FeGa/Fe 3Ga 

thin films 

Dang Duc Dung 1 , Duong Anh Tuan 2 , Yooleemi Shin 2 and Sunglae Cho 2 * 

1 Department of General Physics, School of Engineering Physic,Ha Noi University of 

Science and Technology, 1 Dai Co Viet road, Ha Noi, Viet Nam 

2 Department of Physics, University of Ulsan, Ulsan 680-749,, Korea 

The anomalous Hall effect (AHE) is a central topic in the study of the ferromagnetic materials because 

it exhibit one of the strong evidence for spin polarization [1]. There are three main mechanisms for AHE 

including intrinsic deflection, side jump and skew scattering. The AHE in intrinsic homogeneous magnetic 

material is related to spin polarize due to difference state of spin up and spin down at the Fermi energy 

level and matched to the Berry phase theory [2]. In inhomogeneous magnetic material, AHE implies the 

presence of spin dependent scattering mechanism. The skew scattering dominates at low temperature, 

while the side jump becomes important at high temperature [3]. Recently, we reported the observation of 

weak AHE in FeGa epitaxial thin film on GaAs(001) substrate where FeGa displayed the A2 structure [4]. 

The FeGa were recently rapidly studied because of its giant magnetostrictive characteristics [5, 6]. In this 

work, we report the observation of AHE in nanocomposite FeGa/Fe cGa epitaxial thin film on GaAs(001). 

Unlike FeGa (A2-structure), the strong AHE were shown up to 400 K. Interestingly, the nanocomposite 

FeGa/Fe 3Ga film exhibited strong out-of-plane magnetization. We suggest that the origin of strong AHE 

are magnetization orientation of epitaxial Fe 3Ga (DO3-structure). 

[1] N. Nagaosa et al., Rev. Mod. Phys. 82, 1539 (2010). [2] M. V. Berry, Proc. Roy. Soc. of London 392, 45 (1984). [3] P. 

Xiong et al.,Phys. Rev. Lett. 69, 3220 (1992). [4] D. A. Tuan et al., to be printed in JAP. [5] J. Atulasimha et al., Smart Mater. 

Struct. 20, 043001 (2011). [6] O. M. J. van’t Erve et al., Appl. Phys. Lett. 91, 122515 (2007), and reference therein.

PN30 

MnAs nanoclusters embedded in GaAs: Magnetism and transport 

properties 

Duong Van Thiet 1 , Dang Duc Dung 2 , Yooleemi Shin 3 and Sunglae Cho 3 * 

1 

Department of Physics, University of Ulsan, Ulsan 680-749, Republic of Korea, 

Korea 

2 

Department of General Physics, School of Engineering Physics,Ha Noi University of 

Science and Technology,1 Dai Co Viet road, Ha Noi, Viet Nam 

3 

Department of Physics, University of Ulsan, Ulsan 680-749,, Korea 

The fabrication of magnetic nanocluster embedded in conventional semiconductor is a research trend 

because of their unique physical properties in electronics, optics and magnetism. The understanding of 

magnetic clusters effect on the transport and magnetic properties in semiconductor is timely demanded for 

the spintronic device application. In this work we embedded MnAs nanoclusters in GaAs(001) by growing 

MnAs/GaAs multilayer structure using molecular beam epitaxy. After growing 2000 A GaAs buffer layer 

on GaAs (100) substrate, the [MnAs (20 A)/GaAs (tGaAs)]4 multi-layer configurations were grown at 

400 oC, finally followed by the growth of 200 A-thickGaAs capping layer to avoid the oxidation of inner 

layer. The tGaAs was selected as 100, 200 and 300 A. The reflection high energy diffraction (RHEED) 

exhibited spotty patterns, indicating the island-growth of MnAs nanocluster. The result of cross-sectional 

TEM measurement also showed that MnAs nanocluster are embedded in GaAs matrix successfully. The 

resistance was increased rapidly with decreasing temperature, indicating that the samples demonstrate 

semiconductor behavior. The magnetic properties were carried out by the superconductor quantum interface 

devices (SQUID) measurement, which showed the TC above room temperature. The detail sample growth, 

and magnetic and transport properties of MnAs nanocluster embedded on GaAs will be discussed. 

PN31 

Half-metallic and ferromagnetic properties of carrier doping in Zn1 xCuxO Byung-sub Kang 1 , Kie-moon Song 1 , Yong-sik Lim 1 , Kyeong-sup Kim 2 , Young-yeal 

Song 2 and Seong-cho Yu 2 

1 

Dept. of Nano science and Mechanical engineering, Konkuk University, Korea, 

Democratic Peoples’ Republic 

2 

Dept. of Physics and BK21 Physics Program, Chungbuk National University, Korea, 

Democratic Peoples’ Republic 

Diluted magnetic semiconductors (DMSs) have attracted a great deal of attention because of the 

possibility of incorporating magnetic degrees of freedom in traditional semiconductors. However, 

it is one of the primary challenges to create the ferromagnetic semiconductors due to the difficulty 

in the spin-injection into the semiconductors to form DMSs at room temperature or above room 

temperature. Since ZnO is a direct wide-band gap semiconductor which is piezoelectric, ZnO-based 

DMS would be useful for transparent thin film transistors, blue and UV light-emitting diodes and 

laser diodes. The precipitates of nonmagnetic Cu dopants do not contribute to the magnetism. In 

our work, the stability of ferromagnetic state in ZnO-based DMSs with a concentration of 2.77%, 

5.55%, and 8.33% has been investigated by first-principles calculations. The magnetic moments 

are not affected by changing the doping concentrations, while the band gap is decreased as for 

increasing of Cu concentration. The band gaps in Cu-doped ZnO are 0.65, 0.22, and 0.08 eV for the 

Cu concentration of 2.77%, 5.55%, and 8.33%, respectively. The half-metallic character shows at 

low Cu concentration, while it is disappeared as for increasing of Cu concentration. The effects on 

the electronic state by the hole (Nitrogen) doping have been investigated. 

PO01 

Synthesis and characterization of surface functionalized magnetic 

polymer microspheres with multi-shell structure 

Zuli Liu*, Qing Li and Kailun Yao 

physics, Huazhong university of science and technology, China 

We synthesize magnetic polymer microspheres with amino/ carboxyl groups 

on the surface. We also fabricate the microspheres by incorporating magnetite 

nanoparticles(MPs) into a silica shell around preformed polystyrene(PSt)/SiO 2 

core/shell microspheres. Due to the silanization reaction with 3-aminopropyl 

triethoxysilane(APTES), the outermost silica shell is formed and linked with amino 

group at the same time. And we use PEG diacid to obtain carboxyl functionalized 

microspheres via the reaction between -NH2 and -COOH. Optical microscope and 

scanning electron microscopy(SEM) show that the microspheres are monodisperse 

with the average diameter about 2um; vibrating sample magnetometer(VSM) 

indicates that the synthesized sample with amino-group on the surface exhibits 

superparamagnetism with the saturation magnetization 7emu/g; thermogravimetry(TG) 

reveals that the microspheres are thermally stable when temperature is below 300°C 

and the Fe 3O 4 content is 20.68%. Last, the fluorescence microscope shows that the 

microspheres obtained can be successfully conjugated with biomolecular, including 

streptavidin and antibody. 

PO02 

PO03 

PO04 


Production of Fe 3-xZn xO 4 nanoparticles for agents in hyperthermia 

treatment 

Hiromasa Takeuchi*, Akinobu Kurokawa, Takuya Yanoh, Shinya Yano and Yuko 

Ichiyanagi 

Yokohama National University, Japan 

Fe 3-xZn xO 4(x=0.2, 0.4, 0.6, 0.8, 1) nanoparticle with average diameters 12nm were 

produced by our novel wet chemical method. The crystal structure and magnetic 

property of the obtained particle were investigated by X-ray diffraction and SQUID 

magnetometer. DC magnetization measurement showed that the coercive force Hc and 

saturation magnetization Ms decreased as the composite parameter x increased. This 

phenomenon suggests that Zn 2+ ions located on A-sites weaken the superexchange 

interaction between A and B sites. From the AC magnetic susceptibility, a sample with 

composition of x=0.4 is expected for heating by external field. Temperature increase 

depending on the magnetic field strength and frequency supported that samples 

with composition of x=0.2, 0.4 were appropriate for use as an agent in hyperthermia 

treatment. 

Gene delivery using polyethylenimine-coated magnetic nanoparticles 

by static and oscillating magnetic field 

Yoshiyuki Takahashi 1 , Satoshi Ota 1 , Asahi Tomitaka 1 , Tsutomu Yamada 1 , Daisuke 

Kami 2 , Shogo Takeda 3 , Masatoshi Watanabe 3 and Yasushi Takemura 1 

1 Electrical and Computer Engineering, Yokohama National University, Japan 

2 Kyoto Prefectural University of Medicine, Japan 

3 Materials and Chemical Engineering, Yokohama National University, Japan 

Recently gene delivery without viral vectors attracts rising attention. Low transfection 

efficiencies of nonviral gene vectors such as transfection reagent limit their utility in gene 

therapy. To overcome this disadvantage, we report a transfection method using cationic 

polymer polyethylenimine(PEI)-coated magnetic nanoparticles and an external magnetic field. 

It shows high transfection efficiency as well as low cytotoxicity. In this study, transfection 

efficiency of plasmid DNA in complex with PEI-coated magnetic nanoparticles was studied. 

HeLa cells were seeded the day before transfection. Immediately before transfection, the PEIcoated 

magnetic nanoparticles (γ-Fe 2O 3) were mixed with plasmid DNA. The complexes were 

incubated and added to HeLa cells on a NdFeB magnet and a coil. After 48 hours, transfection 

efficiency of plasmid DNA to HeLa cells was evaluated by the average percentage of the 

fluorescent cells imaged by a fluorescent microscope in triplicate. The optimal amount of 

magnetic nanoparticles was 3.0 μg/sample on a magnet for 4 h. The transfection efficiency was 

increased five-times compared without magnetic nanoparticles (only PEI). Higher transfection 

efficiency was obtained by applying an ac magnetic field. Further analysis on other parameters 

of an applied magnetic field and endocytosis are reported. 

Fabrication of QD-anchored magnetic nanocomposites for biomedical 

applications 

Hangdeok Oh and Sang-wha Lee* 

Department of Chemical and Bio Engineering, Kyungwon University, Korea 

WITHDRAWN 




PO05 


Determination of biomolecule interaction in magnetic particle by 

voltammetry and ac impedance 

Hoon Song and D. G. Park* 


Magnetic biochip based immunoassay have potential in many fields, such as 

environmental immunoassay, diagnostic immunoassay, and biochemical studies 

and immunosensors [1]. In the field of immunoassays, cyclic voltammetry (CV) 

technique have become known independently as methods suitable for the detection 

of immunological reactions. CV measurements are the current signals based on the 

electrochemical species consumed and/or generated during a biological and chemical 

interaction process of a biologically active substance and substrate. To apply to the real 

biomarker and verify the sensitivity of CV-based sensor, we used the biomarker scheme 

using the applied the real protein on the gold surface. The capture antibodies (P21 

mono antibody) are first immobilized on the positive gold sensor surface. The samples 

with biomarkers (P21 recombination protein) to give antibody and antigen reaction 

are applied on gold surface. After the non specific binding labels were successfully 

removed through the washing progress, only the chemically bounded bio molecules 

were remained on the Au surface. This enables to increase the sensitivity of the sensor 

for the binding of biomolecules on the gold surface. The difference in the CV represents 

the quantity of the antigen of interest and could be applied to the biosensor. 

[1] Choi JW, Chun BS, Oh BK, Lee W, Lee WH (2005) Fabrication of DNA-protein conjugate layer 

on gold-substrate and its application to immunosensor. Coll Surf B 40:173-177 

PO06 

The effects of pulsed magnetic field stimulus on electromyographic 

activity 

Juyeon Seo 1 , Yongjin Kim 1 , Jaehyun Kim 1 , Sunghyun Kim 1 , Do Gwen Hwang 1 , Yunyeop 

Cha 2 and Hyun Sook Lee 1 * 

1 Department of Oriental Biomedical Engineering, Sangji University, Korea 

2 Department of Oriental rehabilitation medicine, Sangji University, Korea 

Pulsed magnetic fields (PMF) conducting impulses toward the deep tissues as well as transcutaneous 

tissues are well known to be alternative non-invasive medical treatment for influencing human 

physiology as compared with acupuncture. In traditional Chinese medicine, acupuncture is used 

clinically to relieve myalgia and many studies have attempted to elucidate its mechanism of 

action [1]. The aim of the present study was to examine the immediate effects of PMF stimulus 

on the electromyographic (EMG) activity at acupoint HT2, Quingling, which is a trigger point as 

hyperirritable spots in biceps brachii muscle on the arm [2]. Six healthy volunteers were asked to 

perform four repetitions of withstanding maximal isometric contraction with 5-kg load and an elbow 

angle of 90o to cause fatigue in biceps brachii muscle on the arm. Analyzing power density spectrum 

from fast Fourier transformation of EMG signal, we observed that median power frequency (MDF) 

decreased and median power increased due to muscle fatigue during isometric contractions. It was 

proved that PMF stimulus on acupoint was effective in relieving muscle pain by means of increased 

MDF and amplitude probability distribution of RMS EMG shifted to high amplitude. Therefore, it 

may be concluded that appropriate PMF stimulus affects neuromuscular function. 

[1] K. Toma, R. Conatser, R. Gilders, and F. Hagerman, J. Strength & Condit. Res. 12(4), 253- 

257(1998). [2] J. Majlesi & H. Unalan, Curr Pain Headache Rep 14,353-360(2010) 

PO07 

Magnetic anisotropy of Co dFe 3-dO 4 nanoparticles for applications in 

magnetic hyperthermia 

Costica Caizer* 

Electricity and Magnetism, West University of Timisoara, Romania 

The magnetic behaviour of the Co dFe 3-dO 4 (d = 0 ~ 1.5) nanoparticles strongly depends on the 

concentration (d) of the cobalt ions within the spinelic ferrite structure; this is a superparamagnetic 

behaviour for low d, a soft magnetic behaviour for moderate d, and a hard magnetic behaviour for high 

d. The d parameter determines a certain value of the magnetocrystalline anisotropy [1]. The effective 

magnetic anisotropy in the case of nanoparticles is a very important intrinsic parameter (besides their 

diameter) to obtain the magnetic hyperthermia (MHT), with a great influence on the specific absorption 

rate (SAR), in the case of their usage in medicine to obtain tumour magnetic hyperthermia (to destroy 

tumour cells) [2,3]. The purpose of this research is to determine the magnetic anisotropy of the Co dFe 3dO 

4 nanoparticles, having the diameters of 2 ~ 17 nm, to identify its origin (magnetocystalline or/ 

and other nature (surface anisotropy or/and shape anisotropy)), and also to establish, based on the 

experimental results, the most suited nanoparticles (as anisotropy and diameter) in order to use them in 

intracellular MHT [4]. The obtained results are presented and discussed in detail in the paper. 

Acknowledgement: This work was supported by PCCA-2012 project from the UEFISCDI-ANCS 

Romania. References [1] R. Valenzuela, Magnetic Ceramics (Cambridge Univ. Press, Cambridge) 

(1994). [2] C.L. Ondeck, A.H. Habib, P. Ohodnicki, K. Miller, C.A. Sawyer, P. Chaudhary, M.E. 

McHenry, J. Appl. Phys. 105 (2008) 07B324. [3]. C. Caizer, N. Hadaruga, D. Hadaruga, G. 

Tanasie, P. Vlazan, 7th Int. Conf. on Inorganic Materials, 12 - 14 Sept. 2010, Biarritz, France. [4] J.P. 

Fortin, F. Gazeau, Eur. Biophys. J. 37 (2008) 223. 


PO08 

Magnetic nanoemulsion as advanced drug delivery system applied to 

synergic procedures in the photodynamic therapy and hyperthermia 

trials using human mesenchymal stem cells as biological model 

Fernando Lucas Primo 1 , Daniela Regina Jardim 1 , Paulo Cesar Morais 2 and Antonio Claudio Tedesco 1 * 

1 Chemistry, Nanotechnology and Tissue Engineering Center, FFCLRP, Sao Paulo University, Ribeirao Preto, SP, Brazil 

2 Physical, Brasilia University - UnB, Physical Institute, Brasilia-DF, 70910-900., Brazil 

Tissue engineering and nanotechnology are important research fields in the future development of biological models 

useful for the understanding of wound healing processes, extracellular matrix activity and other biological skin 

activities[1]. This study reports on the synthesis and characterization of advanced drug delivery system with magnetic 

properties useful to Photodynamic Therapy (PDT) and Hyperthermia (HPT). Magnetic-Nanoemulsion (MNE) was 

obtained from spontaneous nanoemulsification to entrapment/controlled-release of lipophilic drugs as described by 

Siqueira-Moura[2]. The results demonstrated appropriated physical-chemistry stability to MNE biomaterial with size 

< 200 nm, exhibited a narrow size distribution (polydispersity index < 0.1) and zeta potential with modular value 

> Ι40Ι mV. Biological studies were carried out on human bone mesenchymal stem cells determination of in vitro 

biocompatibility after incubation with MNE which shown a safe concentration drug specific for each cellular type. 

Besides, the in vitro synergic effect of PDT and HPT were evaluated after simultaneous induction of photodynamic 

effects and magnetic field (40 Oe) application. These results confirmed that the use of nanotechnology associated 

with PDT and HPT procedures led to in vitro tumor inactivation by advanced protocols that can be useful to future 

oncological treatment. Financial grant CNPq (D.R.J.) and FAPESP projects 2009/15363-9 and 2008/53719-4 (F.L.P.). 

[1] Primo, F L.; Reis, M. B. C.; Porcionatto, M. A.; Tedesco, A. C. In vitro Evaluation of Chloroaluminum Phthalocyanine 

Nanoemulsion and Low-Level Laser Therapy on Human Skin Dermal Equivalents and Bone Marrow Mesenchymal 

Stem Cells. Current Medicinal Chemistry, 18, 3376-3381, 2011. [2] Siqueira-Moura, M.P.; Primo, F.L.; Peti, A.P.F.; 

Tedesco, A.C. Validated spectrophotometric and spectrofluorimetric methods for determination of chloroaluminum 

phthalocyanine in nanocarriers. Pharmazie, 65, 1-6. 2010. 

PO09 

The morphological change of red blood cells in the hand exposed to the 

stimulus of strong pulse magnetic field 

Jinyong Lee 1 , Hyun Sook Lee 1 , Jun Sang Yu 2 and Do Guwn Hwang 1 * 

1 Oriental Medical Engineering, Sangji University, Korea 

2 Oriental Medical, Sangji University, Korea 

The influence of magnetic field on human body has been studied to use as application of 

therapeutic equipment for a long time. Some studies have carefully suggested that vascular 

blood flow volume can be increased by an electromagnetic field stimulus [1-3]. In this 

study, live blood analysis (LBA) of blood collected in the hand stimulated by strong pulsed 

magnetic field was used in vitro to get the morphological change of red blood cells before 

and after magnetic stimulus. The LBA is a test methodology to approach the risk factors of 

illness, states of immunity, nutritional states of cells, degrees of hidden lesions, or treatments 

over time. The analysis can accomplish these goals functionally and preventively by 

observing morphological changes of ingredients constituting blood, which is alive without 

being chromated and collect through peripheral blood vessel. Our system was designed to 

generate a pulsed magnetic field that had a maximum intensity variation of 0.48 T and a 

transition time of 0.102 msec. LBA were done in the blood collected before and after the 

stimulation of 10 minutes in the hand. As a result, the hemadsorption (adhesion of red blood 

cells) observed before stimulus were normally distributed after stimulus of blood. 

[1] D. Roland, M. Ferder, R. Kothura, T. Faierman, and B. Strauch, Plast. Reconstr. Surg. 105, 1371 

(2000). [2] H. N. Mayrovitz and P. B. Larsen, Wounds 4, 197 (1992). [3] H. N. Mayrovitz and P. B. 

Larsen, Wounds 7, 90 (1995). 

PO10 

An analytical comparison in electoencephalography and 

electrocardiography during stimulus of pulsed magnetic field and 

acupuncture on acupoint PC9 

Jinyoung Lee 1 , Do Guwn Hwang 1 , Yun-Yeop Cha 2 and Hyun Sook Lee 1 * 

1 Department of Oriental Biomedical Engineering, Sangji University, Korea 

2 Department of Oriental rehabilitation medicine, Sangji University, Korea 

With recent increasing attention on the pulsed magnetic field stimulus as non-invasive medical 

treatment, diverse studies are being conducted to elucidate its effects on human physiology 

[1]. Among several bio-signals obtained from human body, electroencephalography and 

electrocardiography are known to have no side effect and provide real-time information on 

autonomic nervous activity with spectral analysis. The aim of the present study was to compare the 

changes of EEG and ECG during the PMF and acupuncture stimulus on acupoint, which is known to 

sedation and tonification point. In order to compare qualitatively the effect of PMF and acupuncture 

stimulus, the difference of alpha activities are calculated from EEG spectra compared with before, 

during and after stimulus, and the spectrum curves of ECG were analyzed in the frequency domain 

of heart rate variability. The increase of alpha activities after both stimuli could be explained that the 

impulse of stimulus on PC9 might pass through sensory nerve following meridian and approach the 

cerebral cortex, causing the CNS to be activated for pacifying emotion and calming the mind [2]. 

The decrease in index of sympathovagal activity after both stimuli indicates that parasympathetic 

nerves were activated and the sympathetic nerves were in constrained condition. 

[1] N.M. Shupak, F.S. Prato, and A.W. Thomas, Neurosci. Lett. 363, 157 (2004). [2] H.S. Lee, S.W. 

Kim, D.G. Hwang, IEEE transaction on Magn. 47(10), 3060 (2011).

PO11 

Reliability of a head movement compensation method based on 

minimum norm estimation for magnetoencephalographic recordings 

Sanghyun Lim and Kiwoong Kim* 

brain and cognition measurement lab, KRISS, Korea 

Non-invasive multi-channel recordings of neuronal activity of brain play an important 

role in brain research fields. Magnetoencephalography (MEG) which measures 

magnetic field generated by synchronous firing of group of neurons, has superior 

spatial and temporal resolutions with quick and easy recording procedures. However, 

a movement of subject’s head during recordings makes significant data distortions, 

since the array of multi-channel sensors is not physically fixed to subject’s head. 

One approach compensating these distortions is to utilize a singular-value-truncated 

minimum norm estimation (MNE) method to generate virtual MEG signals at a 

common reference head position. Since MNE is biased to minimize the total output 

power, this approach can be applied to signals which have a number of distinct sources 

generating event related fields (ERF), but not to spontaneous neuronal recordings. 

In this study, we calculated compensation errors of ERF recordings and spontaneous 

neuronal recordings, by comparing real sensor signals to virtually-generated signals, to 

see the reliability of the method for spontaneous recordings. MEG data were recorded 

using a 152-channel whole head helmet MEG system (KRISS MEG system) within a 

magnetically shielded room, and each channel was simulated and compared with each 

time trials. 

PO12 

The effect of small quantities of irradiation damage on the magnetic 

properties of Steel 316. 

Robert Aldus 1 , Jack Muir 1 , Greg Lumpkin 2 and Paolo Imperia 1 * 

1 bragg institute, ANSTO, Australia 

2 IME, ANSTO, Australia 

The Steel 300 series is often used in applications where a non-magnetic steel is 

required. The materials take the austentite FCC crystal structure as opposed to the 

ferrite structure common in magnetic steels. It has previously been suggested that 

large doses of radiation (approximately 1022 ions/cm2) can cause a change in the 

local crystal structure of steel-316 to the ferrite structure and thus creating a magnetic 

signal [1]. We have performed x-ray absorption, x-ray dichroism and neutron scattering 

using WOMBAT at ANTSO where we also commissioned the new ANSTO Oxford 

Instruments cryomagnet. The samples of steel-316 were irradiated to only about 10 15 

ions/cm2 using He + ions. This level of irradiation should not be enough to change the 

bulk crystal structure and yet we observe some magnetic signal. We present our results 

and explanation for our findings. 

PO13 

Study of a hybrid magnet array for an electrodynamic maglev control 

Chan Ham 1 , Kurt Lin 2 , Younghoon Joo 3 and Wonsuk Ko 4 * 

1 Mechatronics Engineering, Southern Polytechnic State University, USA 

2 Mechanical, Materials, and Aerospace, University of Central Florida, USA 

3 Kunsan Nat’l University, Korea 

4 Kyungwon.Univ, Korea 

This paper introduces an innovative hybrid array consisted of both permanent and electro magnets 

that would enable us to develop an active control mechanism for underdamped EDS Maglev 

systems. The proposed scheme is based on the Halbach array configuration in order to take the 

major technical advantage from the original Halbach characteristics: a strongly concentrated 

magnetic field on a side of the array and a cancelled field on the opposite side. The magnetic force 

produced by the proposed hybrid array can also be actively controlled. This force controllability 

resulted from a variable magnetic field is instrumental to provide a dynamic damping force to 

compensate the instability of EDS Maglev system caused by external perturbations and guideway 

irregularities. In this study, the magnetic characteristics and capability of the proposed array 

compared to the basic Halbach concept are focused. The results show that the proposed array is 

capable to produce an equivalent suspension force of the basic Halbach permanent magnet array but 

in a controlled mode. The effectiveness of the proposed array confirms that this study can be used as 

a technical framework to develop an active control mechanism for an EDS Maglev system. 

[1] Donald M. Rote and Yigang Cai, “Review of Dynamic Stability of Repulsive-Force Maglev Suspension Systems,” IEEE 

Transactions On Magnetics, Vol. 38, No. 2, 1383-1390, March 2002 [2] R. F. Post and D. D. Ryutov, “The Inductrack: A 

Simpler Approach to Magnetic Levitation,” IEEE Transactions on Applied Superconductivity, Vol. 10, 901-904, 2000 

PO14 

PO15 

PO16 


FEM simulation of magnetic treatment of surface vessel 

Yongmin Kim 1 , Hwiseok Kim 2 , Kwan-seob Yoon 3 , Seon-ho Lim 3 , Jaewon Doh 2 , 

Young-hak Kim 4 and Kwang-ho Shin 1 * 

1 

Dept. of Information and Communication Engineering, Kyungsung University, 

Korea 

2 

S/W R&D Center, Project 5 team, LIGNex1, Korea 

3 

S/W R&D Center, Project 4 team, LIGNex1, Korea 

4 

Dept. of Information and Communication Engineering, Pukyong National 

University, Korea 

Since most of surface vessels and submarines are constructed with ferromagnetic materials, mainly 

Fe-C, Magnetic treatment (Deperm) of surface vessels and submarines is required to camouflage 

them against magnetic detection from enemy marine force. We investigated whether we could 

analyze practically magnetic treatment process of a surface vessel with FEM simulation. Because 

a surface vessel has non-linear ferromagnetic property as well as complicated structure with very 

large dimension, it is impossible to analyze the magnetic treatment process through conventional 

FEM using scalar material constants. We tried to do the FEM analysis a hysteresis model. The 

magnetic property including hysteresis of the constructing material of the submarine was calculated 

with the hysteresis model, and compared with the material property measured with the ferrite yoke 

method. The alternating magnetic field applied to the submarine in FEM analysis had several tens 

steps, and the maximum field was 1000 A/m. The analysis results showed that overall magnetic 

remanence was almost the same with that of hysteresis model. However, it was found that the 

magnetization in the endpiece of the vessel was changed non-linearly. The simulated results could 

be analyzed with the ferromagnetic exchanging coupling of magnetic nodes in FEM model. 

Magnetically exchange-coupled nanoparticles as efficient heat inductor 

Seung Ho Moon, Jung-tak Jang, Seung-hyun Noh, Jae-hyun Lee and Jinwoo Cheon* 

Chemistry, Yonsei University, Korea 

The conversion of electromagnetic energy into heat by nanoparticles has the potential 

to be a powerful, non-invasive technique for biotechnology, but poor conversion 

efficiencies have hindered practical applications so far. We demonstrate a significant 

increase in the efficiency of magnetic thermal induction by nanoparticles. We 

take advantage of the exchange coupling between a magnetically hard core and 

magnetically soft shell to tune the magnetic properties of the nanoparticle and 

maximize the specific loss power (SLP), which is a gauge of the conversion efficiency. 

We simulated SLP as a function of magnetocrystalline anisotropy K, diameter of the 

nanoparticle D, and magnetization M. The dependency on K chiefly results from the 

internal magnetic spin fluctuation (Neel relaxation), and the dependency on D is due 

to both Neel and Brownian relaxation. Our simulation indicates the optimal range of 

K and D for nanoparticles with high SLP values. High magnetization M is beneficial, 

too. The optimized core-shell magnetic nanoparticles have SLP values that are an order 

of magnitude larger than conventional iron-oxide nanoparticles. We also perform an 

antitumour study in mice, and find that the therapeutic efficacy of these nanoparticles is 

superior to that of a common anticancer drug. 

Nature Nanotech. 2011, 6(7), 418-422 

Theranostic magnetic nanoparticles 

Seung-hyun Noh, Dongwon Yoo, Jae-hyun Lee, Jung-tak Jang, Seung Ho Moon and 

Jinwoo Cheon* 

center for evolutionary nanoparticles, Korea 

The property of magnetic materials can be defined using some parameters such as 

saturation magnetization(Ms), coercivity(Hc), and magnetocrystalline anisotropy(K). 

Understanding the interplay of these parameters is critical for optimizing magnetic 

characteristics we need for their effective use. We can control these parameters by 

changing the shape, size and composition of nanoparticles. Because there are various 

species of application of nanoparticles and magnetic properties needed to be optimized 

in each field of application are all different flexible tuning of magnetic parameters 

is very important. Important capabilities of magnetic nanoparticles are the external 

controllability of magnetic heat generation and magnetic attractive forces for the 

transportation and movement of biological objects. We show that these functions can 

be utilized not only for therapeutic hyperthermia of cancer but also for controlled 

release of drugs through the application of an external magnetic field. Additionally, the 

use of magnetic nanoparticles to drive mechanical forces is demonstrated to be useful 

for molecular-level cell signaling and for controlling the ultimate fate of the cell. The 

wide range of accessible features of magnetic nanoparticles underscores their potential 

as the most promising platform material available for theranostics. 




PO17 


Ion-texturing & Dynamics in Layered Compounds: From Electric Automobiles to Frustrated Magnetism 

Martin Mansson 1 *, Jun Sugiyama 2 , Kazuhiko Mukai 2 , Yutaka Ikedo 3 , Hiroshi Nozaki 2 , Kazuya Kamazawa 2 , 

Masashi Harada 2 , Marisa Medarde 4 , Fanni Juranyi 5 , Jorge Gavilano 5 , James S. Lord 6 , Isao Watanabe 7 , Ekaterina 

Pomjakushina 4 , Kazimierz Conder 4 , Vladimir Pomjakushin 5 , Tsutomu Ohzuku 8 and Tsunehiro Takeuchi 9 



3 Muon Science Laboratory, KEK, Japan 

4 LDM, Paul Scherrer Institut, Switzerland 

5 Lab. for Neutron Scattering, Paul Scherrer Institut, Switzerland 

6 ISIS, Rutherford Appleton Laboratory, United Kingdom 

7 Muon Science Laboratory, RIKEN, Japan 

8 Department of Applied Chemistry, Osaka City University, Japan 

9 Department of Applied Physics, Nagoya University, Japan 

The drastic change from an antiferromagnetic to a superconducting state in cuprates exemplifies how a slight change in 

carrier-density strongly governs magnetic and electronic properties. In cuprates the intermediate ion-layers are thought 

to only serve as 'passive' charge-reservoirs. However, it has become increasingly clear that also ion-order within these 

layers is of great importance [1]. Further, it was recently demonstrated that also ion-dynamics needs to be considered. In 

the Na 0.8CoO 2 compound it was shown that the low-T magnetic properties could be connected to Na dynamics a much 

higher temperatures [3,4]. From the context of rechargeable Li-ion batteries for electrical cars, our group has recently 

presented a novel experimental method [5] to investigate microscopic ion-dynamics in lithium-transition-metal-oxides 

(Li-TMO). By using the μSR technique we have obtained results regarding ion-dynamics in a wide range of Li-TMO's 

[6-7]. We will here give an overview of the method/results as well as discuss their importance for the development of 

thin-film batteries for the future. Finally, we will also present our latest results regarding Na-dynamics in magnetically 

frustrated compound Na xCoO 2. With the use of μSR, neutron quasi-elastic neutron scattering and diffraction, we show 

how solid state dynamics is imperative for tuning this compound's magnetic/electronic/thermoelectric properties. 

[1] Y. Sassa et al., PRB 83, 140511(R) (2011) [2] W. Bao et al., arXiv:1102.3674v1 (2011) [3] T. F. Schulze et al., PRL 100, 026407 (2008) [4] 

M. Weller et al., PRL 102, 056401 (2009) [5] J. Sugiyama et al., PRL 103, 147601 (2009) [6] J. Sugiyama et al., PRB 82, 224412 (2010) [7] J. 

Sugiyama et al., PRB 84, 054430 (2011) Funding Source: Swiss National Science Foundation (Project 6, NCCR MaNEP) and Toyota CRDL. 

PO18 

Large resistive switching phenomenon induced by magnetic field in 

nano conduction path formed in SiO 2 

Shintaro Otsuka, Tomohiro Shimizu*, Takashi Kato, Takuya Kyomi and Shoso 

Shingubara 

Kansai University, Japan 

A large magnetoresistance (MR) exceeded 800% was observed in a nano conduction 

path (NCP) formed in SiO 2 layer sandwiched between Co film and Si substrate. 

Applied a high voltage of 20 MV / cm between the Co film and the backside of 

Si substrate, the NCP was formed by dielectric breakdown of SiO 2 layer. The 

Magnetoresistance of the NCP in in-plane magnetic field for NCP was measured. 

Using Ni layer instead of Co, the large MR also appeared, but could not be observed 

in the case of using non-magnetic materials. The structure of the device was similar to 

the resistive switching memory device, regarding Co layer and Si substrate as top and 

bottom electrode. Therefore we also measured I-V characteristic of the NCP device, 

and the resistive switching effect was observed. We haven’t fully understood the 

mechanism of this large MR switching phenomenon yet. However, it is speculated that 

the atomic scale NCP consisted of Co atoms was formed due to dielectric breakdown 

of SiO 2, and the nano gap in NCP was formed by magnetic field. 

Jpn. J. Appl. Phys., 50 (2011) 06GG15. 

PO19 

Size dependence simulation of saturated field in circular permalloy 

Xinghao Hu, Byunghwa Lim, Ilgyo Jeong and Cheolgi Kim* 

Department of Materials Science and Engineering, Chungnam National University, 

Korea 

Manipulation of magnetic beads for biomoleculars and cells separation, purification and 

sensing application is of great fundamental and practical interest [1]. On-chip magnets 

of soft magnetic structure of permalloy is a classic manipulation systems for magnetic 

beads, which utilizes external magnetic fields for control of the magnetic beads [2]. 

The maximum of magntic force generated by on-chip magnet in an applied field should 

be obtained for transportation of magnetic beads. We present a simulation method that 

is available to enable a maximum value of magnetic force under an advisable field. As 

shown in simulations, when the applied field is gradually increased to 130 Oe on the 

on-chip magnet of 5 um radius, the magnetization of the on-chip magnet is saturated 

that means a maximum value of magnetic force is obtained. Therefore, this simulation 

method can assist researchers to obtain the advisable field for maximum of magntic 

force in designing variform on-chip magnets. 

[1] J. Dobson, Nat. Nanotech., 2008, 3, 139. [2] K. Gunnarsson, P. E. Roy, S. Felton, J. Pihl, P. 

Svedlindh, S. Berner, H. Lidbaum, and S. Oscarsson, Adv.Mater., 2005, 17, 1730. 


PO20 

A new definition of magneto-mechatronics and applications 

Sung Hoon Kim*, Jaewon Shin, Shuichiro Hashi and Kazushi Ishiyama 

Research Institute of Electrical communication, Tohoku University, Japan 

Recently, magnetic wireless sensors and actuators have been developed for use in biomedical fields. In 

particular, their mechanisms depend on magnetics, such as magnetic material and physical phenomena. 

However, their research boundary has not been clear. Researchers talk of magnetic micro-robots, magnetic 

actuators and sensors, and so on [1-3]. Therefore, a new and correct definition is required. Magneticmechatronics 

is synergistic integration of magnetic engineering, mechanical engineering, and electronics/ 

computer engineering in the design, manufacturing, and control process. In particular, magneticmechanical 

mechanisms are directly controlled by external magnetic fields. Magneto-mechatronics is 

offered as a new definition of magnetic sensors and actuators. In this study, we introduce and investigate 

methods of magnetic field control and their suitable magnetic mechanisms. In general, the control methods 

and mechanisms are determined according to the types of magnetic field: gradient, alternating, and 

rotating magnetic fields. Because the magnetic field controls are suitable for use in the restricted spaces, 

magnetic devices based on magneto-mechatronics can be widely used medical applications. In magnetomechatronics, 

the combination of magnetic, mechanical, and computer engineering provides physical 

hardware, system modeling, and analysis, whereas the combination of magnetic, electrical, and computer 

engineering provides control methods and its algorithm, and an interface, and so on. 

[1] K. Ishiyama, M. Sendoh, A. Yamazaki, and K. I. Arai, “Swimming Micro-machine driven by Magnetic Torque,” Sens. 

Actuators A, Phys. 91, 141-4, 2001. [2]L. Zhang, J. J Abbott, L. Dong , K. E. Peyer, B. E. Kratochvil, H. Zhang, C. Bergeles. 

and B. J. Nelson, “Characterizing the Swimming Properties of Artificial Bacterial Flagella,” Nano Letters 9, 3663-3667, 

2009. [3]S. Hashi, M. Toyoda, M. Ohya, Y. Okazaki, S. Yabukami, K. Ishiyama, and K. I. Arai, “Magnetic motion capture 

system using LC resonant magnetic marker composed of Ni-Zn ferrite core,” J. Appl. Phys. 99, 08B312, 2006. 

PO21 

AC magnetic field frequency dependence of drug release characteristics 

for magnetic hyperthermia based polymer-drug encapsulate system 

for cancer treatment applications 

Tejabhiram Yadavalli 1 , Shivaraman Ramasamy 1 , Gopalakrishnan Chandrasekaran 1 

and Ramasamy R 2 

1 Nanotechnology Research Centre, SRM University, India 

2 School of Pharmacy, SRM University, India 

Ferromagnetic nickel, cobalt and gadolinium ferrite nanomaterials with Curie 

temperature values in the range of 40-50°C have been synthesized by wet chemical 

routes. These nanoparticles were then coated with Poly n-isopropyl Acrylamide 

thermo-sensitive polymer and doxorubicin drug forming a drug-polymer-nanoparticle 

conjugate. The conjugate was then tested for the drug release characteristics invitro 

by the application of alternating magnetic field to it. The study was conducted 

to understand the heating rate of the nanoparticles in the conjugate system and the 

quantitative drug release due to the heating of the nanoparticle. The quantitative study 

was conducted using a homemade magnetic hyperthermia setup and High Precision 

Liquid Chromatography (HPLC) with doxorubicin standards. The study was conducted 

in the range of 100 to 1000 kHz with 20 W power rating. The maximum heating 

rate and the drug release rate per minute was seen at around 900 kHz which was in 

concurrence with the theoretical calculations done using the hysteresis loop area of the 

material. These results will later be useful for testing on animal models to analyze invivo 

drug release characteristics of the conjugate. 

PO22 

Account of the image forces in the Bi 1-xSb x-insulator film structures. 

Konstantin Nicolaevich Kashirin 

The Russian State Agrarian University-Moscow Timiryasev Agricultural Academy, 

Kaluga Branch, Russia 

Semiconducting alloy Bi 1-xSb x (x=0,11) films of the different fixed thickness with a thin layer 

of insulating coating (SiO 2) of variable thickness are investigated. The measuring of kinetic 

parameters was conducted in a superconducting solenoid gap (with magnetic induction to 9 T) and 

on the different temperatures (4,2÷200 K). The calculations of magnetic resistance, of the carries 

mobility and the Hall coefficient was done. The resistance oscillations is observed depending on 

the thickness of insulating coating for all films. The kinetic parameters oscillations was observed 

as function of coating thickness at different temperature and on magnetic field. So, the following 

should be noted by the results of experimental investigations: - the resistance oscillations of all 

investigated bismuth-antimony alloy films is observed depending on the thickness of dielectric 

coating and the period of oscillations is amounts 80-100 A average; - the magnetic resistance and 

the Hall coefficient oscillate with the variation of the dielectric coating thickness in antiphase 

with the analogous oscillation resistance; - the sphere of negative magnetic resistance is observed. 

One of the possible mechanisms accounting for the oscillations of the kinetic parameters of 

semiconducting films with insulator coating is taking into accounts the image forces. 

Semiconducting alloy Bi 1-xSb x (x=0,11) films of the different fixed thickness with a thin layer of insulating coating 

(SiO 2) of variable thickness are investigated. The measuring of kinetic parameters was conducted in a superconducting 

solenoid gap and on the different temperatures. The calculations of magnetic resistance, of the carries mobility and the 

Hall coefficient was done. The assumptions that the one of the possible mechanisms accounting for the oscillations of the 

kinetic parameters of semiconducting films with dielectric coating is taking into accounts the reflection forces were done.

PO23 

Time-resolved pump-probe measurement of polarization rotation in 

nano-structured chiral metamaterial 

J. H. Woo 1 , H. -y. Shin 1 , M. J. Gwon 1 , M. Vomir 2 , M. Barthelemy 2 , D. -w. Kim 1 , S. 

Yoon 1 , J.-y. Bigot 2 and J. W. Wu 1 * 

1 Department of Physics & CNRS- Ewha <strong>International</strong>, Ewha Womans University, Korea 

2 CNRS-IPCMS, University of Strasbourg, France 

In this study, we performed time resolved pump-probe measurement in two nano-structured 

metamaterials with opposite chirality which were fabricated by e-beam lithography on 30nm thick 

gold film. Transient absorption was measured to investigate the temporal behavior of the polarization 

rotation in metamaterial. It is well known that surface plasmonic resonances in metamaterial 

are originated from its structure rather than composition [1,2]. Surface plasmonic resonances in 

metamaterials which were used in this study were located in the visible spectral range with resonance 

peaks at 625nm and 670nm and an optical rotatory dispersion was observed. Time resolved pumpprobe 

measurements were carried out with 35fs Ti:sapphire laser operating at 800nm. BBO crystal was 

used to generate a 400nm pump pulses. For the probe, a sapphire crystal plate was used to generate a 

white light continuum. With linearly polarized pump beam, the electron dynamics in the metamaterial 

structure was studied. Also with right and left circularly polarized pump, we investigated the time 

dependent rotation of polarization of the probe beam in a polarization bridge configuration. 

[1] V. A. Fedotov, M. Rose, S. L. Prosvirnin, N. Papasimakis, and N. I. Zheludev, “Sharp trapped-mode resonances in 

planar metamaterials with a broken structural symmetry”, Phys. Rev. Lett. 99, 147401 (2007). [2] Boyoung Kang, E. 

Choi, Hyun-Hee Lee, E.S. Kim, J. H. Woo, J. Kim, Tae Y. Hong, Jae H. Kim, and J.W. Wu, “Polarization angle control 

of coherent coupling in metamaterial superlattice for closed mode excitation”, Opt. Express 18, 11552 (2010). 

PO24 

Structural and magnetic properties of glassy like carbon synthesized 

by pyrolysis of sucrose 

Shivaraman Ramaswamy* and C Gopalakrishnan 

Nanotechnology Research Center, SRM University, India 

The structure and properties of glassy carbon (GC), a technologically important and 

widely used material, is still not well established. The glassy carbon samples were 

produced by a low-temperature pyrolysis of sucrose. The thermal destruction occurred 

in five stages to minimize carbon losses. At the first stage (175 °C, 3 h) a viscous melt 

was obtained due to detachment of volatile components and water. After the second 

and the third stages (300 °C, 1 h and 400 °C, 0.5 h, respectively) the material becomes 

solid. The next stage (525 °C, 1h) and the last stage (700 °C, 1 h) are performed to 

complete removal of all volatile impurities. The samples were then characterized using 

AFM and SEM to determine its structure and morphology. The magnetic properties 

were studied using vibrating sample magnetometer. It was found that the glassy carbon 

sample has an inherent fullerene like morphology whose concentration increases 

with increased heat treatment. Further, the samples also exhibited a distinct change in 

magnetic properties based on the pyrolysis. Paramagnetic and diamagnetic properties 

were found in the samples. The same has been explained based on the composition of 

the samples and structural properties. 

[1] A.A. Ovchinnikov and V.N. Spector, “Organic ferromagnets. New results,” Synth. Met., vol. 27, 

pp. 615-624, Dec. 1988. [2] H. Ohldag, et al., “Electron Ferromagnetism in Metal-Free Carbon 

Probed by Soft X-Ray Dichroism”, Phys. Rev. Lett., vol. 98, May 2007. 

PO25 

Simulation of energy dispersive mode for RITA-type cold neutron 

triple axis spectrometer SIKA 

Guochu Deng 1 *, Peter Vorderwisch 2 , Chun-ming Wu 2 , Garry Mcintyre 1 and Wenhsien 

Li 2 

1 Bragg Institute, Australian Nuclear Science and Technology Organization, Australia 

2 Department of Physics, National Central University, Jhongli 32054, Taiwan, 

Australia 

SIKA is a high flux cold-neutron triple axis spectrometer in Bragg Institute. Equipped with a multiblade 

analyser system (13 PG(002) blade) and position sensitive detector, SIKA possesses high 

flexibility to efficiently run in a traditional step-by-step mode or various mapping (or dispersive) 

modes by changing the configuration of analysers and detectors. In this study, the energy dispersive 

modes, namely the so-called E1 mode [1] at two different energy transfers is simulated using Monte 

Carlo ray-trace package SIMRES. [2] The simulated results show that SIKA could effectively work 

on E1 mode at low and intermediate energy transfer with reasonable energy and Q resolutions. The 

energy resolution is around 0.23meV at Ei=5meV while it increases to1.8meV at Ei=15meV. This 

simulation shows SIKA has the potential in operation flexibility and data-acquisition efficiency, and 

provides valuable references to the future inelastic neutron scattering experiments on SIKA. 

[1] Lefmann K, McMorrow D F, Ronnow H M et al. 2000 Physica B 283 343 [2] ©aroun J and 

Kulda J 1997 Physica B, 234-236 1102 [3] Shirane G, Shapiro Stephen M, and Tranquada John 

M, 2002, Neutron scattering with a triple-axis spectrometer, (Cambridge University Press) p 123 

[4] Clausen K N et al. 1998 Physica B 241-243 50 [5] Demmel F, Grach N and Ronnow H M 2004 

Nuclear Instruments & Methods in Physics Research Section A 530 404 

PO26 

PO27 

PO28 


Efficiency of Energy base deperm protocol 

Yongmin Kim 1 , Young-hak Kim 2 and Kwang-ho Shin 1 * 

1 Dept. of Information and Communication Engineering, Kyungsung University, 

Korea 

2 Pukyong National University, Korea 

Magnetic treatment of surface vessels and submarines (Deperm) is a required to 

camouflage them against magnetic detection from enemy marine force. So far, deperm 

has been accomplished by applying an alternating magnetic field of which amplitude 

decreases linearly. However, the reduction of the residual flux density in the direction 

of magnetic field is not linear in the case of the linear protocol, since the ferromagnetic 

material used to construct a surface vessel, mainly Fe-C, shows a nonlinear behavior in 

an alternating magnetic field. This is one of main reasons to make an ordinary deperm 

protocol inefficient. In this paper, we propose an energy base deperm protocol which 

calculated by an algebraic hysteresis model, and present how to optimize the deperm 

protocol with the minor loops of magnetic hysteresis. We found out that step number 

could be reduced in the energy base deperm protocol compare with in the linear 

protocol, because the larger numbers of deperm steps are dedicated in the irreversible 

domain process region on the magnetic hysteresis. 

Effect of a magnetic field on mixed convection of a nanofluid in a 

square cavity 

G. A. Sheikhzadeh 1 *, S. Mazrouei Sebdani 1 , M. Mahmoodi 2 , Elham Safaeizadeh 3 and 

Sayed Ebrahim Hashemi 1 

1 Mechanical Engineering Department, University of Kashan, Iran 

2 Mechanical Engineering Department, Amirkabir University of Technology, Iran 

3 Department of Mathematics, Payame Noor University, Najafabad, Isfahan, Iran 

The problem of mixed convection in a differentially heated lid-driven square cavity 

filled with Cu-water nanofluid under effect of a magnetic field is investigated 

numerically. The left and right walls of the cavity are kept at temperatures of Th and 

Tc respectively while the horizontal walls are adiabatic. The top wall of the cavity 

moves in own plane from left to right. The effects of some pertinent parameters such as 

Richardson number (ranging from 0.1 to 10), the volume fraction of the nanoparticles 

(ranging 0 to 0.1) and the Hartmann number (ranging from 0 to 100) on the fluid flow 

and temperature fields and the rate of heat transfer in the cavity are investigated. It 

must be noted that in all calculations the Prandtl number of water as the pure fluid is 

kept at 6.8, while the Grashof number is considered fixed at 10 4 . The obtained results 

show that the rate of heat transfer increases with an increase of the Rayleigh number, 

while but it decreases with increase in the Hartmann number. Moreover it is found 

that by increase in volume fraction of the nanoparticles the rate of heat transfer can be 

enhanced or deteriorated compared to the based fluid. 

Magnetohydrodynamic free convection in a square cavity heated from 

below and cooled from other walls 

Ali Akbar Abbasian Arani*, Mostafa Mahmoodi and Saeed Mazrouei Sebdani 

Mechanical Engineering, University of Kashan, Iran 

Magnetohydrodynamic free convection fluid flow and heat transfer in a square cavity 

filled with an electric conductive fluid with Prandtl number of 0.7 has been investigated 

numerically. The horizontal bottom wall of the cavity was kept at Th while the side 

and top walls of the cavity were maintained at a constant temperature Tc with Th>Tc. 

The governing equations were solved numerically while the SIMPLER algorithm was 

used. A parametric study was performed, and the effects of the Rayleigh number and 

the Hartman number on the fluid flow and heat transfer were investigated. The results 

showed that temperature distribution and flow pattern depended on both strength of the 

magnetic field and Rayleigh number. For all cases two rotating eddies were formed. 

Using the longitudinal magnetic field results in a force (Lorentz force) opposite to the 

flow direction that tends to decrease the flow velocity. The magnetic field decreased the 

free convection and flow velocity. Also it was found that for higher Rayleigh numbers 

a relatively stronger magnetic field was needed to decrease the heat transfer. Moreover 

for low Rayleigh numbers, by increase in the Hartman number, free convection is 

suppressed and heat transfer occurs through conduction mainly. 




PO29 


Interaction of a magnetic field and buoyancy force in a square cavity 

filled with a fluid with low Prandtl number 

G. A. Sheikhzadeh 1 *, S. E. Hashemi 1 , S. Mazrouei Sebdani 1 , M. Mahmoodi 2 and 

Elham Safaeizadeh 3 

1 

Mechanical Engineering Department, University of Kashan, Iran 

2 

Mechanical Engineering Department, Amirkabir University of Technology, Tehran, 

Iran 

3 

Department of Mathematics, Payame Noor University, Najafabad, Isfahan, Iran 

In this paper, influences of Lorentz force due to a magnetic field on buoyancy 

driven heat transfer in a square cavity containing a fluid with low Prandtl number is 

investigated numerically. The left and right walls of the cavity are kept at temperatures 

of Tc and Th respectively, while the horizontal walls are kept adiabatic. Effect of 

existence of an adiabatic body in the middle of the cavity is considered too.The 

dimensionless governing equations associated with the boundary conditions are solved 

numerically using the finite volume method. Streamlines and isotherms are shown 

for Grashof number (ranging from 10 5 to 10 7 ), Hartman number (ranging from 0 to 

100) and Prandtl number (ranging from 0.005 to 0.1). The results show that variations 

of magnetic field donot have noticeable effect on buoyancy force, while increase 

in magnetic field increases Lorentz force. Moreover buoyancy and Lorentz forces 

increase by increase in Grashof number in a constant Hartman and Prandtl numbers. 

PO30 

Numerical study of magnetic field effects on flow field and heat 

transfer in a cavity filled with porous materials 

G. A. Sheikhzadeh*, M. Aliakbari Miyan Mahaleh, A. A. Abbasian Arani and S. 

Mazrouei Sebdani 


Natural convection flows in a square cavity filled with a fluid-saturated porous medium 

under the effect of magnetic field has been studied numerically. A square hot body 

with length W is placed in the center of the cavity (with length L). The ratio of W/L is 

assumed to be 0.5. Continuity, momentum and energy equations are solved using the 

finite volume technique under the boundary conditions. The two vertical sides of the 

cavity are cooled and two horizontal bottom and top walls are adiabatic. The Prandtl 

number is 0.71, the Rayleigh number changes from 10 4 to 10 6 , the Darcy number 

varies from 10 -5 to 10 -3 and the Hartmann number alters from 0 to 100. Numerical 

results are presented in terms of stream functions, temperature profiles. The results 

say increasing the braking effect of magnetic field as increasing the Hartman number; 

lead to decreases the heat transfer. Also at low Darcy number, fluid circulation is weak 

due to high hydraulic resistance offered by porous medium for Darcy number down 

to 10 -5 . Average Nusselt number increases with enhancement of Rayleigh number and 

decreasing the Hartmann number. 

PO31 

Numerical simulation of magnetohydrodynamic Benard convection in 

a shallow enclosure 

G. A. Sheikhzadeh*, M. Mahmoodi and S. Mazrouei Sebdani 


In this paper the problem of magnetohydrodynamic Benard convection in a shallow 

rectangular enclosure with aspect ratio of 10 (width to height ratio) has been 

investigated numerically. The enclosure is filled with an electric conductive fluid with 

Prandtl number of 1. The bottom and the top walls of the cavity are maintained at a 

constant temperature Th and Tc respectively, with Th > Tc, while; the side walls of the 

cavity are kept insulated. The governing equations written in terms of the primitive 

variables are solved numerically using the finite volume method and the SIMPLER 

algorithm is employed to couple velocity and pressure fields. Using the developed 

code, a parametric study is performed, and the effects of the Rayleigh number and 

the Hartman number on the fluid flow and heat transfer inside the enclosure are 

investigated. The results show that temperature distribution and flow pattern inside 

the enclosure depend on both the strength of the magnetic field and Rayleigh number. 

Moreover it was found that at low Rayleigh number with increase in Hartman number 

the flow intensity decreases and fluid becomes stagnant. At high Rayleigh numbers 

number of the Benard cell decreases by increase in Hartman number. 


PO32 

Near-electrode effcets of magnetic fields in electrochemistry 

Michael Coey and Peter Dunne 

Physics, Trinity College dublin, Ireland 

Remarkable influences of magnetic fields have been discovered on the diffusion layer 

and on the electrochemical double layer. The former are mainly due to magnetic 

pressure, which allows the patterning of deposits from both paramagnetic and 

diamagentic ions (using a nonelectroactive paramagnetic species such as Dy 3+ ). 

The effects of small cylindrical [1] and linear magnet arrays are demonstrated. The 

magnetic patterning is estimated to be effective down to about the 100 micron scale. 

The essential requirement for patterning of this type are orthogonal concentration 

gradients and magnetic field gradients. More surprising is the evidence we have found 

for an influence of a static magnetic field on the electrochemical double layer, a poorly 

understood region about 1 nm thick at the cathode. Using a nitrobenzene model redox 

system, we show that the double layer capacitance can be modified by a factor of two 

at an appropriate potential. The influence of Maxwell stress on the free radicals in 

solution is discussed as a possible explanation. More remarkable are 

[1] P. Dunne, L. Mazza and J. M. D. Coey, Phys Rev Letters 107 042501 (2011) 

QA01 

Resonant magnetic x-ray scattering: Beamline P09 at PETRA III at 

DESY 

Joerg Strempfer, Sonia Francoual, Dinesh K. Shukla and Arvid Skaugen 

DESY, Germany 

Resonant and non-resonant magnetic scattering are complementary tools to magnetic 

neutron diffraction for the investigation of magnetic properties in solids. Resonant 

magnetic x-ray scattering opens the possibility to investigate magnetic order in single 

crystals and layered systems element selectively. Also the interference of magnetic 

order with orbital or charge order can be determined through the polarization properties 

of the x-ray and the special form of the scattering cross sections, describing the 

variation of the polarization states through the scattering process. The new beamline 

for Resonant Scattering and Diffraction (RSD), P09 at PETRA III, is designed 

especially to address the above mentioned issues. Low temperature cryostats and high 

magnetic fields of up to 14T allow the investigation of magnetic properties of materials 

as function of polarization, temperature and field. Two diffractometers are available to 

conduct experiments using the highly brilliant synchrotron beam available at PETRA 

III. The polarization of the incident x-ray beam can be varied arbitrarily through x-ray 

phase-plates and the polarization of the scattered beam is analyzed by a polarization 

analyzer. Examples for the performance of the beamline and experimental results on 

magnetic scattering from multiferroic systems will be presented. 

QA02 

Magnetic and dielectric properties of FeTiO 3 

Takayasu Kiyokawa 1 *, Shigeki Yamada 1 and Takatsugu Masuda 2 

1 Nanosystem Science, Yokohama City University, Japan 


The magnetic and dielectric properties of single crystal iron ilmenite FeTiO 3 have been 

investigated. The temperature dependence of the magnetization for H parallel to the c 

axis (M//c) has a sharp peak at 58 K (T N) and abruptly decreases below T N, while the 

magnetization for H perpendicular to the c axis (M┴c) is almost independent of the 

temperature. These features indicate that the ground state is Neel state with the easy 

axis in the c direction. Above T N the value of M//c is larger than that of M┴c due to the 

magnetic anisotropy. These results are consistent with previous report by Kato et al.. 

The temperature dependence of the dielectric constant for E parallel to the c axis also 

shows a kink at T N. Furthremore the dielectric polarization for E parallel to the c axis 

abruptly increases at T N. Hence this kink is ascribed to ferroelectric phase transition. 

These results indicate that FeTiO 3 is a strong candidate for a new type of multiferroic 

materials.

QA03 

Theoretical study of tuning polarization and magnetism of BiCoO 3 

Yu-jun Zhao and Xing-yuan Chen 

Department of Physics, South China University of Technology, China 

QA04 

QA05 

WITHDRAWN 

Soft x-ray synchrotron radiation spectroscopy study of 

Co 0.6Fe 0.9Mn 1.5O 4 spinel with nano-checkerboard patterns 

D.h. Kim 1 , Jihoon Hwang 1 , Eunsook Lee 1 , S.-w. Cheong 2 , B.-g. Park 3 , J.-y. Kim 3 and 

J.-s. Kang 1 * 


2 Department of Physics and Astronomy, Rutgers University, USA 

3 Pohang Accelerator Laboratory, POSTECH, Korea 

In the AB 2O 4-type spinels, transition-metal ions occupy either the tetrahedral (Td) A 

site or the octahedral (Oh) B site. Recently, nano-checkerboard (CB) patterns have 

been observed in ZnMnGaO 4, MgMn 1.5Fe 0.5O 4, and Co 0.6Fe 0.9Mn 1.5O 4 [1]. When 

properly annealed, these spinels show two different structures with different chemical 

phases, where one is cubic and the other is tetragonal or orthorhombic. This structural 

and chemical phase separation has been explained by the Jahn-Teller (JT) distortion. To 

confirm this idea, it is important to determine the valence states of the transition-metal 

ions that constitute these spinel oxides. In this work, we have studied the electronic 

structure of checkerboard Co 0.6Fe 0.9Mn 1.5O 4 single crystal by employing soft x-ray 

absorption spectroscopy (XAS) and soft x-ray magnetic circular dichroism (XMCD). 

The measured T 2p XAS spectra (T=Co, Fe, Mn) of Co 0.6Fe 0.9Mn 1.5O 4 reveal that the 

valence states of Co, Fe, and Mn ions are nearly divalent (Co 2+ ), trivalent (Fe 3+ ), and 

mixed-valent (Mn 2+ -Mn 3+ ), respectively. Very weak XMCD signals are observed in 

checkerboard Co 0.6 Fe 0.9 Mn 1.5 O 4. *Corresponding Author : kangjs@catholic.ac.kr 

[1] C.L. Zhang, et al., Appl. Phys. Lett. 91, 233110 (2007). 

Zn-substitution effects in multiferroic Cu 3Mo 2O 9 

Haruhiko Kuroe 1 *, Kento Aoki 1 , Ryusuke Itoh 1 , Tomohiro Hosaka 1 , Takuya 

Hasegawa 1 , Suguru Hachiuma 1 , Mitsuru Akaki 1 , Hideki Kuwahara 1 , Tomoyuki 

Sekine 1 , Masashi Hase 2 , Kunihiko Oka 3 , Toshimitsu Ito 3 and Hiroshi Eisaki 3 


2 National Institute for Material Science (NIMS), Japan 

3 National Institute of Advanced Industrial Science and Technology (AIST), Japan 

We present the Zn substitution effects on the quasi-one dimensional frustrating spin 

system Cu 3Mo 2O 9. This material has S = 1/2 distorted tetrahedral spin chains and 

undergoes the multiferroic phase below 7.9 K without magnetic field [T. Hamasaki 

et al., Phys. Rev. B 77 (2008) 134419, H. Kuroe et al., J. Phys. Soc. Jpn. 80 (2011) 

083705]. The S = 0 Zn 2+ ions substitute for the S = 1/2 Cu 2+ ions at the three 

crystallographically different sites, namely Cu 1, Cu 2, and Cu 3. The spins at the Cu 2 and 

Cu 3 sites form nearly spin-singlet spin dimers at the bisectors of the nearest neighbor 

C u1 sites in the quasi-one dimensional spin chain [H. Kuroe et al., J. Phys.: Conf. Ser. 

200 (2010) 022028, H. Kuroe et al., Phys. Rev. B 83 (2011) 184423]. In this study, 

we focus on the magnetic, electric, and thermodynamical properties of the single 

crystal of (Cu,Zn) 3Mo 2O 9. Comparing our previous results in polycrystalline samples 

[M. Hase et al., J. Phys. Soc. Jpn. 77 (2008) 034706], we discuss the reduction of the 

antiferromagnetic correlation and the singlet-pair breaking effect on the Cu 2-Cu 3 spin 

dimers. The dielectric constant and the specific heat in (Cu,Zn) 3Mo 2O 9 will also be 

discussed in this study. 

QA06 

QA07 

QA08 


Effects of bismuth substitution on the magnetic properties of BixCo2 xMnO4 Maria Elenice Dos Santos 1 , Paulo Noronha Lisboa-filho 2 and Octavio Pena 1 

1 

Institut des Sciences Chimiques de Rennes, Universite de Rennes 1, France 

2 

Laboratorio de Materiais Eletronicos, Universidade Estadual Paulista, Brazil 

Coexistence of magnetism and ferroelectricity, along with coupling between them, ensures many 

technological applications of materials named multiferroics. Transition metal and/or rare earth 

oxides with ABO 3 perovskite and AB 2O 4 spinel structures are good candidates due to the substitution 

of magnetic and non-magnetic ions at the A and/or B sites [1]. Bi-substituted Bi xCo 2-xMnO 4 

multiferroic samples, well-characterized structurally by XRD and Rietveld refinement together with 

SEM-EDX techniques, were synthesized by a polymeric precursors method. A gradual expansion 

of the lattice parameter due to the substitution of Co 3+ by Bi 3+ is observed for x = 0.1, 0.2 and 0.3. 

Magnetic characterization was carried out by SQUID measurements. The inverse susceptibility 

exhibited ferrimagnetic behaviour, as also proved by the strong antiferromagnetic and ferromagnetic 

interactions shown by the ZFC and FC curves. The M(H) loops performed at various temperatures 

below T C showed larger loop areas when decreasing the temperature, indicating an increasing 

ferromagnetism. The inclusion of Bi in Co 2MnO 4 creates fluctuating valence states of both Co 

and Mn ions (Co 2+ /Co 3+ , Mn 2+ /Mn 3+ /Mn 4+ ) which occupy the tetrahedral and octahedral sites [2]. 

Magnetization measurements showed that T C and M S increase with increasing Bi 3+ concentration 

due to the redistribution of the magnetic cations, in particular the Mn 3+ and Mn 4+ ones. 

[1] P. Barahona, et. al. J. Chil. Chem. Soc. 50. N 2 (2005) 495. [2] N. E. Rajeevan, et. al. Mater. Sci. 

Eng. B 163(2009) 48. 

Cross-correlation effects in multiferroic Cu 3Mo 2O 9 

Ryusuke Itoh 1 *, Tomohiro Hosaka 1 , Takuya Hasegawa 1 , Haruhiko Kuroe 1 , Tomoyuki 

Sekine 1 , Masashi Hase 2 , Kunihiko Oka 3 , Toshimitsu Ito 3 and Hiroshi Eisaki 3 

1 Sophia University, Japan 



We present the cross correlation effects in a multiferroic material Cu 3Mo 2O 9. This 

material contains spin tetrahedra made from the Cu 2+ ions which form a edge 

sharing spin chain. The quasi-one dimensional magnon dispersion curve, the 

ferroelectric properties caused by the geometrical magnetic frustration, and a strong 

magnetocapacitance effect have been reported [H. Kuroe et al., Phys. Rev. B 83 

(2011) 184423, H. Kuroe et al., J. Phys. Soc. Jpn. 80 (2011) 083705]. In this study, we 

focus on the change of the longitudinal magnetization under the electric field. Using 

a SQUID magnetometor which has two electric leads, we measured the longitudical 

magnetization Ma along the a axis and the electric polarization Pc along the c axis of 

a plate-like single crystal of Cu 3Mo 2O 9 simultaneously. We measured the longitudinal 

magnetization along the a axis (Ma-Ha loop) under the static electric field Ec along the 

c axis, and the Ma-Ec loop under the static Ha. The details of our results including the 

change of the Ma-Ha loop under the static electric field and butterfly-loop in the Ma-Ec 

loop will be presented in this study. 

Nonlinear current-voltage characteristics of (La 0.5Eu 0.5) 0.7Pb 0.3MnO 3 

Single crystals: Possible manifestation of the internal heating of charge 

carriers 

Kirill Shaykhutdinov* 

Kirensky Institute of Physics, Russia 

Current--voltage characteristics of the polycrystalline substituted lanthanum manganite 

La 0.7Ca 0.3MnO 3 were experimentally studied at Т = 77.4 K in magnetic fields up to 13 

kOe. In these characteristics, a portion of negative differential resistivity was observed 

above a certain threshold value of critical current density j caused, in our opinion, 

by nonequilibrium heating of the electron gas due to low thermal conductivity of the 

manganite material. Because of the nonlinearity of the current--voltage characteristics, 

the field dependences of resistivity ρ(H) appear extremely sensitive to the value of a 

transport current. In this case, the ρ(H) dependences reveal both ordinary negative and 

positive magnetoresistance. 


Poster Tuesday

Poster Tuesday 


QA09 

High field phase diagram in multiferroic Cu 3Mo 2O 9 

Haruhiko Kuroe 1 *, Ryo Kino 1 , Ryusuke Itoh 1 , Tomohiro Hosaka 1 , Takuya Hasegawa1, 

Tomoyuki Sekine 1 , Takumi Kihara 2 , Masashi Tokunaga 2 , Masashi Hase 3 , Kanji 

Takehana 3 , Hideaki Kitazawa 3 , Kunihiko Oka 4 , Toshimitsu Ito 4 and Hiroshi Eisaki 4 





We present the multiferroic behavior in the quasi-one dimensional antiferromagnet Cu 3Mo 2O 9. 

This material has spin chains of the distorted spin tetrahedra made from S = 1/2 Cu 2+ ions. 

In ICM2009, we have presented that the magnon dispersion relation in Cu 3Mo 2O 9, which is 

well explained by the hybridization effects between a magnon excitation from the quasi-one 

dimensional spin system and that from the isolated spin dimers [H. Kuroe et al., J. Phys.: Conf. 

Ser. 200 (2010) 022028, H. Kuroe et al., Phys. Rev. B 83 (2011) 184423]. Recently, we found 

that this material shows a multiferroic behavior [H. Kuroe et al., J. Phys. Soc. Jpn. 80 (2011) 

083705]. We proposed that the origin of the multiferroic behaviors in Cu 3Mo 2O 9 is the charge 

redistribution effect in a frustrated Mott insulator studied by Bulaevskii et al.[L. N. Bulaevskii 

et al., PRB 78 (2008) 024402.], which is presented by Khomskii as an invited talk in ICM2009 

[D. I. Khomskii, J. Phys.: Condens. Matter 22 (2010) 164209]. In this study, we present 

the magnetic-field-temperature phase diagram up to 55 T obtained from the temperature 

and magnetic-field dependences of the magnetization, the dielectric constants, the electric 

polarization, the pyroelectric current, and the specific heat. 

QA10 

Magnetoelectric effect in Ca 2FeAlO 5 

Nobuyuki Abe 1 *, Khanh Duy Nguyen 2 , Yoichi Nii 2 , Yutaro Kitagawa 3 and Taka-hisa 

Arima 1 



3 Department of Applied Physics, The University of Tokyo, Japan 

Ca 2FeAlO 5 has the same crystal structure as mineral Brownmillerite. The oxygen deficient 

perovskite type structure is constructed by the alternate stacking of (Fe,Al)O 6 octahedra and 

(Fe,Al)O 4 tetrahedra. An early structure analysis showed that Ca 2FeAlO 5 belongs to a noncentrosymmetric 

space group Ibm2 [1], which originats from the in-phase stacking of (Fe,Al) 

O 4 tetrahedra. This compound shows antiferromagnetic order below 350 K. Mossbauer 

spectroscopy measurements conclude that the magnetic moments of Fe 3+ align along the 

a-axis[2]. Because the crystal structure lacks the inversion symmetry, Ca 2FeAlO 5 is a 

candidate material which has a magnetoelectric coupling. Here we show the measurements 

of magnetoelectric effect in single crystalline Ca 2FeAlO 5. The field dependence of the 

magnetization along the a-axis shows a metamagnetic transition caused by the spin flop of 

Fe 3+ moments. Moreover, the dielectric constant and electric polarization show an anomaly 

at around the phase transition. These results indicate that Ca 2FeAlO 5 shows magnetoelectric 

effect in a magnetic field induced spin flop phase, which is one example of a new route to 

realize a magnetoelectric coupling above the room temperature. 

[1] A. A. Colville and S. Geller, Acta Cryst, B27, 2311(1971) [2] R. W. Grant et.al. , J. Appl. Phys. 

39, 1122 (1968) 

QA11 

Electronic and magnetic phase separation in the semimetallic 

ferromagnet EuB 6 

Pintu Das 1 , Adham Amyan 1 , Jens Brandenburg 1 , Jens Mueller 1 *, Peng Xiong 2 , 

Stephan Von Molnar 2 and Zachary Fisk 3 

1 Institute of Physics, Goethe University Frankfurt, Germany 

2 Dept. of Physics, Florida State University, Tallahassee, USA 

3 Dept. of Physics, University of California, Irvine, USA 

EuB 6 is a low-carrier semimetal, which undergoes a unique paramagnetic to ferromagnetic 

transition displaying two consecutive features at T c1= 15.5 K and T c2 = 12.6 K in electrical 

transport, magnetization and specific heat. Its structural and electronic simplicity makes EuB 6 

an ideal model system for studying the effect the magnetic state of a system has on its electronic 

transport properties. In particular, the fundamentals of intrinsic electronic and magnetic phase 

separation can be studied, which play a critical role for the colossal magnetoresistance (CMR) 

in magnetic semiconductors and manganites. In explaining CMR in EuB 6, being largest at 

T c1, the concept of magnetic polaron (MP) percolation has been invoked. We report resistance 

noise and weakly nonlinear transport measurements, being sensitive to the microgeometry of 

the electronic system. We find direct evidence for electronic phase separation when cooling 

through T c1 and a diverging noise level at T c2, which we interpret as magnetically-driven 

percolation resulting from the overlap of spatial inhomogeneities in conductivity produced 

by MP. Interestingly, MP percolation can be induced also by applying magnetic fields in the 

paramagnetic region. We find that the density of MP can be described by a universal scaling 

function, being related to a single critical magnetization. 


QA12 

Study of magnetic and magnetodielectric properties of perovskite 

YbCrO 3 

Jong-suck Jung, Ayato Iyama*, Hiroyuki Nakamura, Yusuke Wakabayashi and 

Tsuyoshi Kimura 

Division of Materials Physics, Osaka University, Japan 

Perovskite YbCrO 3 shows the G-type antiferromagnetic ground state for Cr 3+ moments 

(T N ~ 118 K). Because of the Dzyaloshinskii-Moriya interaction, the G-type structure 

becomes canted, and then YbCrO 3 exhibits weak ferromagnetism. When weak 

magnetic fields are applied (B ≤ 0.3 T), temperature-induced magnetization reversal is 

observed. The magnetization reversal is probably associated with a keen competition 

between antiferromagnetically coupled Cr 3+ - Yb 3+ moments. Recently, a distinct 

magnetodielectric effect was observed in another perovskite SmMnO 3 which also 

shows temperature-induced magnetization reversal due to the competition between 

antiferromagnetically coupled Mn 3+ - Sm 3+ moments [1]. Thus, it is intriguing to study 

magnetodielectric properties of YbCrO 3. In this study, we investigated magnetic and 

magnetodielectric properties for single crystals of YbCrO 3 grown by the flux method. 

The comparison of magnetodielectric properties between YbCrO 3 and SmMnO 3 

provides useful information to understand the distinct magnetodielectric effect 

observed in SmMnO 3. 

[1] J.-S. Jung et al. Phys. Rev. B 82, 212403 (2010) 

QA13 

Interplay among spin, orbital, and lattice degrees of freedom in a 

frustrated spinel Mn 3O 4 

Yoichi Nii 1 *, Hiroshi Umetsu 1 , Hajime Sagayama 2 , Nobuyuki Abe 2 , Kouji Taniguchi 2 

and Taka-hisa Arima 2 

1 Dept. of Phys., Tohoku University, Japan 

2 Dept. of Advanced Mater. Sci., The University of Tokyo, Japan 

Spinel oxides, AB 2O 4, are one of the typical systems for studying the effects of geometrical 

frustration and the possible coupling among spin, orbital and lattice degrees of freedom. Mn 3O 4 

exhibits the cooperative Jahn-Teller (JT) transition from cubic to tetragonal structure at 1443 K with 

the 3z2-r2 ferro-orbital order at B-site Mn 3+ . The gigantic JT distortion (~16 %) would encourage 

the formation of one-dimensional (1D) antiferromagnetic spin chains at B-site Mn 3+ normal to the 

c-axis. A macroscopic degeneracy of the arrangements of 1D-spin-chains still remains, even if one 

considers the magnetic interaction between the nearest neighbor 1D-chains. It was reported that 

Mn 3O 4 exhibits successive magnetic phase transitions from paramagnetic to Yafet-Kittel (43 K), 

incommensurate (IC) (40 K) and commensurate (C) phase (34 K)[1], which is an indicative of the 

surviving magnetic frustration. Another phase transition is induced by applying magnetic field in the 

low-temperature C phase [2]. In order to elucidate the magnetic-field induced phase transition, we 

have measured synchrotron x-ray diffraction and neutron scattering in a magnetic field along [100] 

c. We propose a scenario of the magnetic-field induced phase transition, where the rearrangement of 

1D-spin-chains is triggered by orbital hybridization at B-site Mn 3+ through the spin-orbit coupling. 

[1] R. Tackett et al., Phys. Rev. B 76, 024409 (2007). [2] T. Suzuki et al., Phys. Rev. B 77, 220402(R) (2008) 

QA14 

Structural and dielectric study of hexagonal Y 0.8Sr 0.2MnO 3 Compound 

Rajesh K. Thakur 1 *, Rasna Thakur 2 , A. Bharathi 3 and N.k. Gaur 2 

1 Department of Physics, Barkatullah University,Bhopal, India 

2 Department of Physics, Barkatullah University, Bhopal, India 

3 Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre 

for Atomic Research, Kalpakkam, India, India 

Strontium doped YMnO 3 compound have been prepared in single-phase form by 

using high temperature solid sate reaction method. The structural and dielectric 

properties of the prepared sample have been carried out in the wide range of 

temperature and frequency. Temperature and frequency variations of dielectric 

permittivity measurements show that the present hole doped YMnO 3 compound 

exhibits a competing interaction in between the ferromagnetic double - exchange 

and antiferromagnetic super-exchange interactions, further a weak signature of 

ferromagnetic ordering at lower temperature has been witnessed. Our resistivity 

measurement reveals that the material is highly insulating at lower temperature just 

below the reported AFM transition in this class of materials.

QA15 

Controlling the superparamagnetic limit using the magnetoelectric 

effect 

Hyungsuk K. D. Kim 1 , Laura Schelhas 2 , Sarah Tolbert 2 and Gregory P. Carman 3 * 

1 Department of Materials Science and Engineering, UCLA, USA 

2 Department of Chemistry and Biochemistry, UCLA, USA 

3 Department of Mechanical and Aerospace Engineering, UCLA, USA 

MRAM (Magnetic Random Access Memory) is attracting considerable attention as a possible candidate 

for next generation of non-volatile memory devices. Major challenges facing scientists today are 

overcoming thermal instability and reducing the writing energy. As bit density increases, this requires 

smaller magnetic regions to be written magnetically at small scales and external energies become 

a dominant feature. For example in the small scale, thermal energy becomes larger than magnetic 

anisotropy, resulting in superparamagnetic behavior. For a given small scale size, the temperature 

above which superparamagnetism begins is referred to as the blocking temperature. Superparamagnetic 

behavior is undesirable due to limits it places on the size of a bit of information. Recently, researchers 

have begun to study magnetoelectric (ME) memory related to some issues with memory. Their focus 

has been on writing processes using electric field-induced strain rather than addressing the more 

challenging topic of controlling superparamagnetism. Here we report experimental results showing the 

introduction of a magnetoelectric anisotropy energy to alter the blocking temperature and thus control the 

superparamagnetic behavior. This is achieved via an electric field-induced strain in a ME composite. Our 

results show 50 K increase of the blocking temperature with the application of an electric field. 

1. Y. Jun, J. Seo, J. Cheon, Accounts of chemical research 41, 179 (2008). 2. F. Zavaliche et al., Nano letters 7, 1586 (2007). 

3. T. Wu et al., Applied Physics Letters 98, 012504 (2011). 4. M. Bibes, A. Barthelemy, Nature Materials 7, 425 (2008). 

QA16 

Magneto-Capacitance Effect and Electric Polarization in Spinel 

Co 2MnO 4 

Sun Hee Kang 1 , San Youn Park 2 , Ill Won Kim 1 , Yoon Hee Jeong 3 and Tae Yeong 

Koo 4 * 

1 Physics Department, Ulsan University, Korea 

2 Physics Department, Pohang Univsersity of Science and Technology, Korea 

3 Physics Department, Pohang University of Science and Technology, Korea 

4 Pohang Accelerator Laboratory, Korea 

Structural phase diagram of spinel Co 3-xMn xO 4 (1.0 ≤ x≤ 2.0) was reexamined at the 

room temperature with a focus on the cubic-tetragonal phase boundary. A specific 

composition of Co 2MnO 4 (x=1.0) was selected from the phase diagram study under 

the requirement of both high ferrimagnetic transition temperature (Tc) and non-mixed 

structural phase condition. Experimental result of magnetization measurements and 

local distortions due to the Jahn-Teller Mn 3+ ions support the stabilization of Yafet- 

Kittel type magnetic configuration in the cubic inverse spinel Co 2MnO 4. Correlation 

between the observed forced magnetization - a continual increment of magnetization 

above the saturation field - and magneto-capacitance effect (MCE) was clarified. MCE 

of up to 7 % at 8 T around Tc was observed without an appreciable hysteresis and 

nonlinearity in the field variation. Diffraction-spectroscopy techniques were also used 

to identify the local chemical and structural environments of both Co and Mn ions at 

two crystallographic sites of the spinel structure. 

QA17 

Magnetically induced polarization in copper metaborate CuB 2O 4 

Khanh Duy Nguyen 1 , Nobuyuki Abe 2 , Masashi Tokunaga 3 , Mitsuru Saito 1 and Takahisa 

Arima 2 * 

1 Deparment of Physics, Tohoku University, Japan 



Intriguing electro-magneto optic effect of non-centrosymmetric magnet copper metaborate has 

attracted huge consideration during last time [1]. In here we report the magneto-electric behavior of 

CuB 2O 4 under external magnetic field. It is well known that CuB 2O 4 undergoes a phase transition 

from paramagnetic state to canted-antiferromagnet at 21 K, then followed by a second transition 

to spiral order around 10 K. Although the magnetic structure at low temperature below 10 K has 

not completely been made clear yet, some evidences of incommensurate helical order in this 

range of temperature have been observed [2]. Result of magnetization measurement points out 

the existence of an anomaly around 1, 3 T at 2 K, then disappeared when increasing temperature 

above 10 K, which may be attributed to the transition from commensurate to incommensurate 

phase. Furthermore, electric polarization was also observed by applying a magnetic field along the 

[110] and [1-10] axes without poling electric field in low temperature regime. The magnitude of 

polarization in static field was found to be compatible with the measurement in pulse magnetic field. 

Besides novel optical characteristic, these results show the ability of generation and control electric 

polarization by magnetic field in CuB 2O 4 as well as application to opto-electronic devices. 

[1] M. Saito, K. Ishikawa, S. Konno, K. Taniguchi and T. Arima, Nature Mater. 8, 634 (2009) [2] M.Boehm, B. Roessli, J. 

Schefer, A. S. Wills, B. Ouladdiaf, E. Lelievre-Berna, U. Staub and G. A. Petrakovskii, Phys. Rev. B 68, 024405 (2003) 

QA18 

QA19 

QA20 


Impedance spectroscopy of ferromagnetic oxide: Pr 0.6Sr 0.4MnO 3 

D V Maheswar Repaka 1 and Mahendiran Ramanathan 2 

1 PHYSICS, National University of Singapore, Singapore 

2 Physics, National University of Singapore, Singapore 

In recent years, coupling between electrical and magnetic polarizations in multiferroicmagnetoelectrics 

have become a topic of considerable interest due to novel applications and 

fundamental physics involved [1]. Impedance spectroscopy has been extensively used to 

investigate cross coupling between magnetic and electrical dipole ordering. Anomalies in lowfrequency 

(f = 1-10 kHz) dielectric constant at magnetic transition have been reported in YMnO 3 

[2], BiMnO 3 [3] etc. However, measurement in MHz range has been hardly reported. In this work, 

we report temperature, frequency and magnetic field dependence of impedance in Pr 0.6Sr 0.4MnO 3 

which shows ferromagnetic transition near room temperature (T C= 303 K). It is found that with 

increasing frequency of the ac current, an anomaly in the form of a sharp peak appears at the 

Curie temperature. A second anomaly in the form of an abrupt decrease occurs at T= 100 K much 

below the Curie temperature. These anomalies are suppressed under external magnetic field. It is 

suggested that the observed anomalies are not necessarily caused by ordering of electrical dipoles. 

The observed features in impedance closely correlate with the magnetization. We suggest that 

impedance spectroscopy in these materials can probe magnetization dynamics, which is often 

neglected in studies of magnetocapacitance effect in multiferroic materials. 

[1] S.W. Cheong and M. Mostovoy, Nat.Mater. 6 (2007) 13. [2] S. Lee, A. Pirogov, M. Kang, K.H. 

Jang, M. Yonemura, T. Kamiyama, S.W. Cheong, F. Gozzo, N. Shin, H. Kimura, Y. Noda, and J.G. Park, 

Nature (London) 451, (2008) 451. [3] R. Seshadri and N. A. Hill, Chem.Mater. 13, (2001) 2892. 

Structures and magnetic properties of Tm 1-yY yMn 1-xCo xO 3 

Toshiyuki Tanaka, Yusuke Amakai, Naoki Momono, Shigeyuki Murayama and 

Hideaki Takano* 

Department of Applied Sciences, Muroran Institute of Technology, Japan 

The structure and magnetic properties of Tm 1-yY yMn 1-xCo xO 3 with 0≤x≤0.5 and 

0≤y≤0.3 were investigated by X-ray diffraction, specific heat and magnetization 

measurements. A thulium manganite TmMnO 3 prepared by the solid state synthesis 

method in ambient pressure is hexagonal and antiferromagnetic with Neel temperature 

T N=86 K. The substitution of Y for Tm in TmMnO 3 does not largely affect the 

fundamental hexagonal structure. We can roughly understand the results of the 

magnetization and the specific heat of Tm 1-yY yMnO 3 in terms of a dilution effect of 

Tm by Y. On the other hand, the structure of TmMn 1-xCo xO 3 gradually changes from 

hexagonal to orthorhombic with the substitution of Co for Mn and hexagonal and 

orthorhombic phases coexist in samples for x≤0.3, and TmMn 0.6Co 0.4O 3 become almost 

orthorhombic single phase. The magnetization of TmMn 0.6Co 0.4O 3 in a field of 250 

Oe increases rapidly below about 60 K with decreasing temperature. The discrepancy 

of the zero-field-cooled (ZFC) and the field-cooled (FC) magnetization remarkablely 

expands below about 60 K. Moreover, temperature dependence of ZFC and FC 

magnetization show peaks at 40 K and 27 K, respectively. TmMn 1-xCo xO 3 we obtained 

shows complicated magnetic properties. 

Complex magnetic and electric orders in multiferroic Co 3TeO 6 

Chin-wei Wang1, Chih-jen Wang1, Wen-hsien Li1*, Chih-chieh Chou2, Hung-duen Yang2, Yang 

Zhao3, Sung Chang3, Jeffrey W. Lynn3 and Helmuth Berger4 

1 Department of Physics and Center for Neutron Beam Applications, National Central University, Taiwan 

2 Department of Physics and Center for Nanoscience and Nanotechnology, National Sun Yat-Sen 

University, Taiwan 

3 NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, USA 

4 Institute of Physics of Complex Matter, EPFL, Lausanne, Switzerland 

Multiferroics, where both ferroelectric and magnetic order coexist, are quite uncommon, but 

are of particular interest both to understand the fundamental interactions between the two 

types of order as well as for the potential for practical applications. The novel metal tellurates 

M3TeO6, where M is a first-row transition metal, have been shown to be rich in crystalline 

chemistry. Ferroelectricity and magnetic-field-driven polarization have been observed. Here, we 

report on the results of neutron diffraction, magnetic susceptibility, specific heat, and dielectric 

constant measurements made on a single crystal Co3TeO6 to study the interplay between 

the ferroelectricity and magnetic order. A strong interplay between the order parameters of 

ferroelectricity and both commensurate and incommensurate magnetic order are observed. Long 

range incommensurate magnetic order develops below TM1=26 K, which is followed by three 

additional zero-field phase transitions at TM2=19.5 K, TM3=18 K, and TM4=16 K where the 

incommensurate order changes and commensurate order develops. In magnetic fields up to 14 T 

we find that the magnetic intensities and incommensurate wave vector are dramatically altered 

as ferroelectricity develops, with a fifth abrupt transition around 10 T. The overall behavior 

characterizes Co3TeO6 as a type-II multiferroic. 


Poster Tuesday



QA21 

Annealing induced colossal magnetocapacitance and colossal 

magnetoresistance in in-doped CdCr 2S 4 

Zhaorong Yang* 

Institute of Solid State Physics, Chinese Academy of Sciences, China 

Colossal magnetocapacitance (CMC) and colossal magnetoresistance (CMR) induced 

by annealing polycrystalline Cd 0.97In 0.03Cr 2S 4 are reported. In agreement with the 

appearance of CMR near the Curie temperature Tc, a insulator-metal transition is 

observed with decreasing temperature at zero magnetic field. On the contrary, after 

the same annealing treatment, CdCr 2S 4 displays typical semiconductor behavior and 

does not show magnetic field dependent dielectric and electric transport properties. 

Accordingly, the simultaneous occurrence of CMC and CMR effects implies that the 

CMC in the annealed Cd .97In 0.03Cr 2S 4 could be explained qualitatively by a combination 

of CMR and Maxwell-Wagner effect. 

QA22 

Critical dynamics in LiCuVO 4 

Christoph Grams 1 *, Maximilian Schalenbach 1 , Daniel Niermann 1 , Petra Becker 2 and 

Joachim Hemberger 1 

1 II. Physikalisches Institut, University of Cologne, Germany 

2 Institut fur Kristallographie, University of Cologne, Germany 

QA23 

WITHDRAWN 

High quality crystal growth and Low temperature diffuse scattering 

studies 

Shilpa Adiga*, Yixi Su, Jrg Persson and Manuel Angst 

PGI-4, Forschungszentrum Juelich, Germany 

The 120 K Verwey-transition [1] in magnetite Fe 3O 4 is the classical example for charge 

ordering, but the complex low-temperature structure was unresolved during decades. 

Early experimental studies and recent calculations suggest ferroelectricity (FE) due 

to charge ordering, which would be significant if confirmed. Very recent structural 

refinement [2] supports the necessary polar structure. Recently, signatures of relaxor 

FE were observed below 40 K [3] . Specific diffuse scattering would be expected in 

such a case [4], best resolved on high quality single crystals. The Verwey transition 

depends sensitively oxygen stoichiometry [5] and the high quality crystals are obtained 

by the direct synthesis in an appropriate CO/CO 2 flow [6].We have grown high quality 

single crystals of magnetite under the tailored growth conditions by optical floating 

zone method and characterized them primarily by specific heat measurement. We 

present the results of high energy x-rays and neutrons diffuse scattering experiments, 

performed to test the proposed relaxor FE. The presence of weak diffuse scattering at 

very low temperature is observed only by neutron scattering, and thus likely magnetic, 

not supporting relaxor FE. Proof of the latter would require time resolved scattering. 

1.E.J.W.Verwey, Nature 144, 327 (1939). 2.Mark S.Senn et al, Nature Letter (2011). 3.F.Schrettle et 

al, Phys. Rev. B. 83 195109 (2011). 4.Grace Yong et al , Phys. Rev. B. 62, 14763 (2000). 5.P.Shepherd 

et al., Phys. Rev. B 43, 8461 (1991). 6.R.Aragon et al., J. crystal growth, 61, 221 (1983) 


QA24 

Anomalous magnetodielectric and magnetostrictive effect via spin 

reorientation in terbium iron garnet 

Ki-myung Song 1 , Seongsu Lee 2 and Namjung Hur 1 * 

1 Dept. of physics, Inha univ., Korea 

2 Neutron Science Division, Korea Atomic Energy Research Institute, Korea 

We have investigated the relationship among the magnetic, dielectric and 

magnetostrictive properties of terbium iron garnet (TbIG). In this presentation, we 

report experimental observations which are extraordinary magnetostriction and 

magnetodielectric effects in TbIG with a non-collinear spin structure in a single 

unit cell. The distinct effects of magnetism on the lattice are also demonstrated by 

the unprecedented magnetostriction with a negative poisson ratio. We attribute the 

observed magnetodielectric effects and the huge magnetostriction to the magnetic field 

induced spin reorientation from non-collinear to collinear. In this study, we analyzed 

crystallographic and spin structure of TbIG in various temperatures by the Fullprof 

program. We investigated the effect of the non-collinear spin structure on the crystal 

structure of TbIG to elucidate the relation between them through analyzing neutron 

diffraction data. 

QA25 

Template based synthesis of multiferroic BiMnO 3 nanotubes and shape 

dependent study of its magnetic properties 

Geo George Phillip, Anuraj Sundar, Mahdiyar Bagheri, Helen Annal Therese* and 

Gopalakrishnan Chandrasekaran 

Nanotechnology Research Centre, SRM University, India 

The synthesis of Bismuth manganite nanotubes was done by templating precursors of 

bismuth and manganese on titanium dioxide nanotubes. The yield was post treated to 

remove the template material and sintered at 400 C. The resulting powders were studied using 

X-ray Diffractometer and Scanning Electron Microscope, which revealed the formation of 

perovskite nanotubes . The BiMnO 3 nanotubes were characterized for its magnetic properties 

by Vibrating sample magnetometer that revealed the intrinsic ferromagnetic nature with 

increase in its magnetic saturation that could have been due to the shape anisotropy of the 

nanotubes. The magnetization under field cooled and zero-field cooled was also found to 

differ significantly with applied magnetic field. These results indicate the co-existence of 

antiferromagnetic behavior at higher temperatures along with its intrinsic ferromagnetic nature 

which deviate from its bulk counterpart that only exhibits ferromagnetic nature. 

1. Srikala, D., Singh, V.N., Banerjee, A., Mehta, B.R.Effect of induced shape anisotropy on magnetic properties of 

ferromagnetic cobalt nanocubes (2010) Journal of Nanoscience and Nanotechnology, 10 (12), pp. 8088-8094. 2. 

Tajiri, T., Harazono, M., Deguchi, H., Mito, M., Kohno, A., Kohiki, S. Synthesis and magnetic property of multiferroic 

BiMnO3 nanoparticles in the pores of mesoporous silica (2010) Japanese Journal of Applied Physics, 49 (6 PART 2), 

pp. 06GH041-06GH044. 3. Xu, E., Qian, T., Zhang, G., Zhang, T., Li, G., Wang, W., Li, X. Fabrication and magnetic 

properties of multiferroic BiFeO3 nanotube arrays (2007) Chemistry Letters, 36 (1), pp. 112-113. 

QA26 

Solitary reentrant superconductivity prediction in asymmetrical 

ferromagnet-superconductor-ferromagnet trilayer 

Yurii N. Proshin*, Marat M. Khusainov, Arthur Minnullin and Mansur G. Khusainov 

Theoretical Physics Department, Kazan Federal University, Russia 

The theory of proximity effect for thin bilayer FS, trilayer FSF and fourlayered system 

FSFS, where F is a ferromagnetic metal, and S is superconductor, is proposed on the 

base of new boundary-value problem for the Eilenberger function. For all systems the 

dependencies of critical temperature on an exchange field of the F metal, electronic 

correlations in the S and F metals, and thicknesses of layers F and S are derived. It 

is shown that the possibility of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state 

observation is especially increased in the asymmetrical systems (FSF' and FSF'S') for 

which solitary reentrant superconductivity is predicted. On the basis of a proximity 

effect we propose new method of probe of electronic parameters of contacting 

materials. If well known BCS superconductor S is used as a probe, one can determine 

the exchange field, the electron-electron constant in various magnetics F for the FS 

structures. It allows us to predict the sign and value of the constant of electron-electron 

interaction in gadolinium and to explain a surprisingly high critical temperature Tc ~ 

5K in the short-periodic Gd/La superlattice [1]. 

P.P. Deen, et al. J. Phys.: Cond. Matt. 17, 3305 (2005).

QA27 

Tuning magnetic order, electromagnons and exchange bias by epitaxial 

strain in BiFeO3 thin films 

Manuel Bibes 1 *, Daniel Sando 1 , Arsene Agbelele 2 , Maximilien Cazayous 3 , Ingrid Infante 4 , Wei 

Ren 5 , Sergey Lisenkov 6 , Cecile Carretero 1 , Agnes Barthelemy 1 , Laurent Bellaiche 5 , Jean Juraszek 2 

and Brahim Dkhil 4 

1 Unite Mixte de Physique CNRS/Thales, France 

2 Universite de Rouen, France 

3 Universite Paris Diderot, France 

4 Ecole Centrale Paris, France 

5 University of Arkansas, USA 

6 Universiy of South Florida, USA 

With a ferroelectric Curie temperature of 1100 K and a Neel temperature of 640K, BiFeO3 is one 

the very few room-temperature multiferroics [1]. Its ferroelectric polarization is as high as 100 μC/ 

cm² and in the bulk it is a G-type antiferromagnet, with a superimposed cycloidal modulation. In 

addition to showing magnetoelectric coupling between its ferroic orders, BiFeO3 also exhibits coupling 

between dynamic lattice and spin excitations (electromagnons), enabling an electrical control of spin 

waves [2]. We have explored the influence of epitaxial strain [3] on the antiferromagnetic properties 

of BiFeO3 thin films. Combining Mossbauer spectroscopy and Raman scattering, we have found that 

the harmonic cycloidal order is stable at low strain but is replaced at higher strain by conventional 

antiferromagnetism. This is accompanied by strong changes in the electromagnon spectra and on their 

dependence on external stimuli. In addition, the mean antiferromagnetic vector progressively rotates as 

strain varies, offering novel strategies to control exchange bias with ferromagnetic overlayers. 

[1] G. Catalan et al, Adv. Mater. 21, 2463 (2009) ; [2] P. Rovillain et al, Nature Mater. 9 975 (2010) ;[3] I.C. Infante et 

al, Phys. Rev. Lett. 105, 057601 (2010) 

QB01 

Magnetic-enhanced electron-phonon coupling and vacancy effect in 

'111' type iron pnictides from first-principles calculations 

Mei Liu 1 and Bin Li 2 

1 Dept. of Physics, Southeast University, China 

2 Department of Physics, Southeast University, China 

We investigate the lattice dynamics in both nonmagnetic and striped antiferromagnetic 

states of '111' type iron pnictides using the density-functional perturbation theory. 

The anisotropic spin-phonon effects lead to the softening of phonon frequencies 

and the renormalization of electron-phonon matrix elements, so as to increase the 

electron-phonon couplings by 68%, 65%, and 0.9% for LiFeAs, NaFeAs, and LiFeP, 

respectively. Taking into account the vacancy effects in the three iron pnictides, we 

find that the electron-phonon couplings are further enhanced by hole doping, yielding 

superconducting transition temperatures close to their experimental values. 

QB02 

Penetration depth and knight shift in iron-based superconductor Ba1 xKxFe2As2 Kazuki Ohishi 1 *, Yasuyuki Ishii 2 , Isao Watanabe 3 , Taku Saito 4 , Hideto Fukazawa 4 , 

Yoh Kohori 4 , Kunihiro Kihou 5 , Chul-ho Lee 5 , Hijiri Kito 5 , Akira Iyo 5 and Hiroshi 

Eisaki 5 

1 

Research Center for Neutron Science and Technology, CROSS, Japan 

2 

Department of Physics, Tokyo Medical University, Japan 

3 

Advanced Meson Science Laboratory, RIKEN, Japan 

4 

Department of Physics, Chiba University, Japan 

5 AIST, Japan 

We have observed temperature and magnetic field dependence of penetration depth λ 

in single crystalline samples of Ba 1-xK xFe 2As 2 (x = 0.27, 0.64, 0.7, 0.8, 0.94 and 1.0) in 

order to clarify the superconducting gap mechanism. We have found that T dependence 

of 1/λ^2 in KFe 2As 2 with H//c and H┴c are completely different. While the T 

dependence of 1/λ^2 observed with H//c is well fitted by a two-full-gap model, T-linear 

behavior is clearly observed below ~T_c/2 with H┴c, suggesting the existence of line 

node. These results are well interpreted when we take into account the horizontal line 

node (line node in ab-plane) in KFe 2As 2. At the presentation, we will also report the T 

and H dependence of λ and Knight shift over a wide x region of Ba 1-xK xFe 2As 2. 

QB03 

QB04 

QB05 


Raman scattering study of the lattice dynamics in LiFeAs and Fe1+yTe1 xSex Youngje Um 

Max-Planck institute, Stuttgart, Germany 

Following the recent discovery of superconductivity in F doped LaFeAsO with Tc of 

26 K, numerous families of the Fe-based superconductors such as REFeAs(O 1-xF x) 

(RE = rare earth), MFe 2As 2 (M = Ba, Ca, Sr, K, ...), LiFeAs/NaFeAs and Fe 1+yTe 1xSe 

x have been found and investigated. Most of these compounds have closely related 

phase diagrams and present an antiferromagnetic parent compound at low temperature, 

which turns superconductor upon doping. A noticeable exception is LiFeAs, in which 

superconductivity is observed already in the parent compound. Recent ARPES results 

suggest strong electron-phonon coupling in LiFeAs, but so far no experimental study 

of its lattice dynamics is available. Here, we present first Raman light scattering 

investigations of lattice dynamics on superconducting LiFeAs. Five of the six expected 

phonon modes are observed, and show a conventional anharmonic behavior. No clear 

evidence for coupling of electron with zone center phonon is observed. Then, we 

present a systematic study of the lattice dynamics in Fe 1+yTe 1-xSe x as a function of Se 

and excess Fe contents, with special emphasis on the Fe phonon. A peculiar doping 

dependence of the mode is observed, which suggests an original coupling of this 

phonon to the low energy spin excitations induced by excess iron. 

Magnetism and Superconductivity in Rb xFe 2-ySe 2 

Kazuki Ohishi 1 *, Shouhei Kototani 2 , Shunsuke Saiki 2 , Yoshiaki Kobayashi 2 , Masayuki 

Itoh 2 and Masatoshi Sato 1 

1 Research Center for Neutron Science and Technology, CROSS, Japan 

2 Department of Physics, Nagoya University, Japan 

The recent discovery of superconductivity in A xFe 2-ySe 2 (A = alkali metal), with 

transition temperatures up to Tc ~ 32 K, has led to a renewed interest for iron based 

chalcogenide systems. A remarkable observation is that, beside the superconducting 

state, a strong antiferromagnetic (AFM) state with magnetic moments up to 3.3μB 

per Fe ion is observed below TN~550 K. The key issue in A xFe 2-ySe 2 is whether AFM 

order and superconductivity cohabit due to phase separation or share a microscopic 

coexistence. We have performed muon spin relaxation/rotation measurements in 

single crystalline samples of superconducting (SC) Rb 0.8Fe 1.6Se 2 (Tc = 29 K) and non- 

SC Rb 0.8Fe 1.6Se 2, which doesn’t show superconductivity, in order to elucidate whether 

there is difference of magnetic state between SC and non-SC samples. In SC sample, 

we found that SC volume fraction is only ~6% and the rest of amount is AFM ordered 

phase, suggesting SC and AFM ordered phases are separated. We found that muon 

spin depolarization increases with decreasing temperature in non-SC sample, while no 

change was observed in SC sample. It suggests the appearance of new magnetic state 

below 40 K in non-SC sample. 

Magnetic Resonant mode in the Spin-Excitation Spectrum of 

Superconducting Rb2Fe4Se5 Single Crystals 

Jitae Park 

Max-Planck-Institute for Solid State Research, Germany 

WITHDRAWN 


Poster Tuesday



QB06 

Magnetic field-induced superconductivity in the canted 

antiferromagnet Eu(Fe0.81Co0.19) 2As2 Vinh Hung Tran 1 *, T A Zaleski 2 , Z Bukowski 1 , L M Tran 1 and A J Zaleski 1 

1 

Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 

50-950 Wroclaw, Poland 

2 


50-950, Poland 

We present results of ac-magnetic susceptibility, dc-magnetization, specific heat and 

magnetotransport measurements on a single crystal of magnetic Eu(Fe 0.81Co 0.19) 2As 2 

superconductor. The compound undergoes multiple phase transitions; from 

paramagnetic to a spin-density-wave (SDW) at TSDW = 80 K, to canted 

antiferromagnetic (C-AF) state at TN = 16.5 K and superconducting (SC) state at Tc 

= 5.15 K at zero field. Upon applying fields both the C-AF and SC states evolve in an 

unconventional manner. Magnetic field distinctly affects the spin canting, resulting in 

separation of the C-AF into two a new C-AF and ferromagnetic phases. The unusual 

behavior of the SC state deserves the observation that Tc can be increased up to 6.5 K 

with magnetic fields applied parallel to the ab-plane of crystals. The observed fieldinduced 

superconductivity is interpreted as a result of a weakening of the orbital pairbreaking 

effect. From the experimental data we propose the field-temperature phase 

diagrams for Eu(Fe 0.81Co 0.19) 2As 2. 

QB07 

Superconductivity and spin fluctuations in Ca 1-xPr xFe 2As 2 

superconductors studied by 75As NMR 

Long Ma 1 *, Gaofeng Ji 1 , Jia Dai 1 , S. R. Saha 2 , J. Paglione 2 and Weiqiang Yu 1 

1 Department of Physics, Renmin University of China, China 

2 Center for Nanophysics and Advanced Materials, Department of Physics, University 

of Maryland, USA 

The observation of superconductivity in the rare earth doped CaFe 2As 2 with Tc as 

high as 47 K is still not understood. Here we report the first NMR study on the newly 

discovered Ca 1-xPr xFe 2As 2 (x=0.075, 0.15) single crystals. The magnetization shows 

superconductivity at ~25 K with a small volume ratio for both samples. A first order 

structural transition from the tetragonal to the collapsed tetragonal phase in both 

crystals is shown by 75As spectra. Residual tetragonal phase is seen in the x = 0.075 

sample with a finite volume, but not seen in the x = 0.15 sample. We also observed 

a sharp drop of Knight shift below Ts in both samples, suggesting a suppression of 

local moments in the collapsed phase. However, the 1/75T1 is enhanced below 50 

K and shows a prominent peak at about 25 K. Such behaviors indicate strong lowenergy 

antiferromagnetic spin fluctuations, with static or quasi-static magnetic ordering 

at low temperatures, which is probably caused by Pr 3+ doping. The absence of the 

residual tetragonal phase and the observation of antiferromagnetic spin fluctuations in 

the x=0.15 sample suggest that superconductivity in Ca 1-xPr xFe 2As 2 is not tied to the 

tetragonal phase and may have a magnetic origin. 

QB08 

Importance and details of the spin excitation spectra in high-Tc 

pnictide superconductors 

Tanmoy Das and A. V. Balatsky 

Theoretical Division, Los Alamos National Laboratory, USA 

One common feature that underlies all high-Tc superconductor families is the development 

of a magnetic resonance peak at or around the antiferromagnetic ‘hot-spot’ vector. This 

feature has proven to give valuable information about the pairing symmetry, and bulk 

Fermi surface properties. We provide a random-phase approximation (RPA) based BCS 

susceptibility calculation using material specific band structure for 122 family of ironpnictide 

and layered iron selenide superconductors. (i) In iron-pnictide, we show that 

when two hole-pockets at Gamma point and the electron pockets at M point are present 

on the Fermi surface, the spin-excitation spectra split into two distinct resonance branches. 

[1] The energy separation between the two resonances is related to the differences in the 

superconducting gaps on two hole-pockets. Again, the momentum resolution between the 

two modes comes from the differences in Fermi surface areas of the two hole-pockets. (ii) 

We also show that when one hole-pocket disappears, one of the resonances disappears. 

Furthermore, when both hole pockets vanish, the magnetic scattering between the 

remaining electron-pockets lead to a change in the gap symmetry from s± to d-wave. The 

latter is observed in the newly discovered iron-selenide superconductors. [2] Finally, we 

will present the resulting spin-excitation spectra for both materials. 

[1] T. Das, and A. V. Balatsky, Phys. Rev. Lett. 106, 157004 (2011). [2] T. Das, and A. V. Balatsky, 

Phys. Rev. B 84, 014521 (2011). 


QB09 

Angular dependence of the resistive upper critical field of an ironbased 

superconductor Fe(Te,Se) in high magnetic fields 

Takanori Kida 1 , Yoshikazu Mizuguchi 2 , Yoshihiko Takano 3 and Masayuki Hagiwara 1 

1 KYOKUGEN, Osaka university, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan 

2 Grad. Sch. Sci. Eng., Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Japan 

3 National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan 

The 11-system FeCh (Ch=S, Se, Te) superconductors are of great importance in 

understanding the mechanism of superconductivity in iron-based superconductors owing 

to their simple structures. Previously, we have reported the temperature dependence of the 

resistive upper critical field (Hc2) on Fe 1.05Te 0.85Se 0.15, which exhibits superconductivity 

at T = 14 K [1,2]. The Hc2 of this compound at low temperature is considerably smaller 

than that expected from the Werthamer-Helfand-Hohenberg model, manifesting the Pauli 

limiting behavior. It suggests that this compound shows the spin-singlet pairing in the 

superconducting state. The anisotropy coefficient of Hc2 decreases from 2.4 near Tc to 

~1 (nearly isotropic) at low temperatures. In this study, we have investigated an angular 

dependence of Hc2 of a single crystal of Fe 1.05Te 0.85Se 0.15 in pulsed high magnetic fields up 

to 52 T. At T = 10 K, the Hc2 increases with increasing Θ, which is the angle between the 

c-axis and applied magnetic fields direction. We have found that the angular dependence of 

Hc2 is well agreement with the Gintzbrug-Landau effective-mass prediction. 

[1] T. Kida et al., J. Phys. Soc. Jpn. Vol.78 (2009) 113701. [2] T. Kida et al., J. Phys. Soc. Jpn. 

Vol.79 (2010) 074706. 

QB10 

Ab initio evidence of strong correlation and large Mott proximity in 

iron-based superconductors 

Takahiro Misawa, Kazuma Nakamura and Masatoshi Imada 

Dept. Appied Physics, Univ. of Tokyo, Japan 

Recently discovered iron-based superconductors have attracted much interest in their 

high superconducting critical temperatures (Tc). Although it is believed that electron 

correlations mediate the unconventional high-Tc superconductivity, their roles are 

not fully understood yet. To clarify electron correlation effects from a microscopic 

point of view, we study the ab initio low-energy effective model for iron-based 

superconductors by using multi-variable variational Monte Carlo method. From 

this ab initio calculations, we show that iron-based superconductors discovered near 

d6 configuration (5 Fe 3d orbitals filled by 6 electrons) is located on the foot of an 

unexpectedly large dome of correlated electron matter centered at the Mott insulator 

at d5 (namely, half filling). The d5 Mott proximity extends to subsequent emergence 

of incoherent metals, orbital differentiations due to the Mott physics and Hund’s-rule 

coupling, followed by antiferromagnetic quantum criticality, in quantitative accordance 

with available experiments. 

QB11 

As-NQR study of LaFeAsO 1-xF x 

Toshihide Oka 1 *, Z Li 2 , S Kawasaki 1 , G F Chen 2 , N L Wang 2 and G -q Zheng 1 

1 Department of Physics, Okayama uiversity, Japan 

2 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, 

Chinese Academy of Science, China 

The discovery of superconductivity in LaFeAsO 1-xF x at superconducting transition 

temperature Tc=26K, followed by that in ReFeAsO 1-xF x(Re:Ce,Pr,Nd,Sm) with 

Tc as high as 55K, has gained much attention. We have performed systematic Asnuclear 

quadrupole resonance(NQR) measurements on LaFeAsO 1-xF x to elucidate 

its superconducting gap structure and mechanism of the Cooper pair formation. 

For x=0.03, we find the spin-lattice relaxation rate(1/T1) exhibits a small upturn at 

TN=58K, below which the spectra become broadened due to the internal magnetic 

field attributed to an antiferromagnetic ordering. Above TN, 1/T1T increases with 

decreasing T due to the antiferromagnetic spin fluctuation(AFSF), which persists in 

the x=0.04,0.06, and 0.08 compounds. A dome-shaped x dependence of Tc is found, 

with the highest Tc=27 K at x=0.06, which is realized under significant AFSF. With 

increasing x further, AFSF decreases, and so does Tc. These features resemble the 

cuprates La 2-xSr xCuO 4, which suggests that AFSF is also important in producing high 

Tc superconductivity in LaFeAsO 1-xF x . In the superconducting state, we find that 1/T1 

decreases exponentially below Tc down to 0.13Tc for x=0.06, which suggests that the 

energy gaps are fully opened. Meanwhile, 1/T1 below Tc decreases nonexponentially 

for x either smaller or larger than 0.06, which is accounted for by impurity scattering.

QB12 

Interplay between 3d- and 4f-electrons in ReFe 1-xCo xAsO (Re = Ce,Gd) 

T. Shang 1 , L. Yang 1 , Y. Chen 1 , L. Jiao 1 , J. L. Zhang 1 , J. Chen 1 , H. Q. Yuan 1 *, N. 

Cornell 2 , A. Howard 2 , A. Zakhidov 2 , M. B. Salamom 2 , F. Ronning 3 , E. D. Bauer 3 and J. 

D. Thompson 3 

1 Department of Physics and Center for Correlated Matter, Zhejiang University, China 

2 UTD-NanoTech Institute, The University of Texas at Dallas, USA 


In order to study the evolution from a high Tc superconductor to a strongly correlated system 

with largely enhanced effective mass in iron pnictides, we have synthesized a series of ReFe 1xCo 

xAsO (x=0-1) polycrystalline samples and characterized their physical properties by 

means of electrical resistivity, magnetization and specific heat. It is shown that, for CeFe 1xCo 

xAsO, the SDW transition of the 3d-electrons is quickly suppressed upon substituting Fe 

with Co and superconductivity appears in a narrow doping range of 0.05



QB18 

Spectroscopy and anisotropies in the magnetic state of iron pnictides 

Belen Valenzuela, Maria Jose Calderon, Gladys Leon, Noel A. Garcia and Elena 

Bascones* 

Theory and Simulations of Materials, Instituto de Ciencia de Materiales de Madrid, 

Spain 

QB19 

QB20 

WITHDRAWN 

Magnetic interactions in iron pnictides 

Maria Jose Calderon, Gladys Leon, Belen Valenzuela and Elena . Bascones* 

Theory and Simulations of Materials, Instituto de Ciencia de Materiales de Madrid, 

Spain 

WITHDRAWN 

Te-doped K 0.80Fe 1.81Se 2-xTe x single crystals 

C T Lin* 

Crystal Growth, Max Planck Institute for Solid State Research, Germany 

We report the growth a serious of Te-substituted K 0.80Fe 1.81Se 2-xTe x (x~0, 0.09, 0.16, 0.34 

and 0.55) single crystals using optical floating-zone technique under application of 8 

bar of argon pressure. Study of XRD indicated that the undoped single crystals contain 

a significant intergrowth of two sets of the c-axis characterized by slightly different 

lattice constants, i.e., the phase separation phenomenon. Our results demonstrate that 

the partial substitution of Se by Te atoms can lead to the expansion of the c-lattice 

constant, whereas the phase separation phenomenon is suppressed continuously with 

the increase of substitution level and vanished at x~0.55. The magnetization data show 

the superconducting transition temperature is gradually depressed for Tc ~32, 27, 25, 

15, and 0 K with the substitution level x~0, 0.09, 0.16, 0.34 and 0.55, respectively. 


QB21 

High-pressure resonant x-ray emission study of Fe 1.01Se 


Jin-ming Chen, S. C. Haw, J. M. Lee, S. A. Chen, K. T. Lu, N. Hiraoka, H. Ishii and K. 

D. Tsuei 

National Synchrotron Radiation Research Center, Taiwan 

The Fe 3d valence states, electron structures and spin states of iron-chalcogenide 

Fe 1.01Se superconductors under pressure up to 45 GPa were probed by resonant 

x-ray emission spectroscopy (RXES) and and x-ray absorption spectra. The Fe 1s3p- 

RXES spectra of Fe 1.01Se at ambient pressure, 6 GPa and 45 GPa were measured to 

deduce the variation of Fe 3d valence states. The 1s3p-RXES data obtained at the Fe 

K edge clearly reveal that unoccupied Fe 3d states exhibit a relatively delocalized 

character, stemming from hybridization of the Fe 3d states with the Fe 4p orbitals. 

The pronounced pre-edge peak at ~7112.7 eV in Fe K-edge x-ray absorption spectra 

of Fe 1.01Se predominantly originates from the dipole transition of a Fe 1s electron to 

unoccupied Fe 3d-Se 4p hybrid bands. The larger compression accompanied with a 

significant distortion around the Fe atoms along the c axis in Fe1.01Se upon applying 

pressure suppresses the Fe 3d-Se 4p and Fe 4p-Se 4d hybridization. The applied 

pressure suppresses the nearest-neighbor ferromagnetic superexchange interaction 

and enhances spin fluctuations on the Fe sites in Fe 1.01Se. Fe1.01Se shows a small net 

magnetic moment of Fe 2+ at ambient pressure. 

QB22 

Microscopic coexistence and competition of magnetism and 

superconductivity in Ba 1-xK xFe 2As 2 : A structural, magnetic, and 

superconducting phase diagram 

Gwendolyne Pascua 1 , Hubertus Luetkens 1 , Erwin Wiesenmayer 2 , Zurab Shermadini 1 , 

Rustem Khasanov 1 , Alex Amato 1 , Hans-henning Klauss 3 and Dirk Johrendt 2 

1 Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland 

2 Department Chemie,, Ludwig-Maximilians-Universitaet Muenchen, D-81377 Muenchen,, Germany 

3 Institut fuer Festkoerperphysik,, TU Dresden, DE-01069 Dresden, Germany 

It is widely believed that in contrast to its electron-doped counterparts, the hole-doped 

compound Ba 1-xK xFe 2As 2 exhibits a mesoscopic phase separation of magnetism and 

superconductivity in the underdoped region of the phase diagram. Here, we report a combined 

high-resolution X-ray powder diffraction and volume-sensitive muon spin rotation (μSR) 

study of Ba 1-xK xFe 2As 2 showing that this paradigm does not hold true in the underdoped 

region of the phase diagram (0 ≤ x ≤ 0.25). Instead, we find a microscopic coexistence 

of the two forms of order. A competition of magnetism and superconductivity is evident 

from a significant reduction of the magnetic moment and a concomitant decrease of the 

magnetoelastically coupled orthorhombic lattice distortion below the superconducting phase 

transition. The doping dependence of structural, magnetic, and superconducting properties is 

completed in a phase diagram (0≤ x ≤ 1) herein presented and discussed. 

[1] E. Wiesenmayer, H. Luetkens et al., Phys. Rev. Lett. 107, 237001 (2011). [2] M. Rotter et al., Nature Physics 5, 141 

(2009). [3] A. A. Aczel et al., Phys. Rev. B 78, 214503 (2008). [4] T. Goko et al., Phys. Rev. B 80, 024508 (2009). 

QB23 

Anomalous superconducting phase in LaFeAsO 1-xH x studied via 75As 

NMR 

N. Fujiwara 1 *, S. Tsutsumi 1 , S. Iimura 2 , S. Matsuishi 2 and H. Hosono 2 

1 Gradutate School of Human & Environmental Studies, Kyoto University, Japan 

2 Frontier Research Center (FRC), Tokyo Institute of Technology, Japan 

LaFeAsO 1-xF x ( La1111 series ) is a prototype of high-Tc pnictides and has been 

investigated extensively by means of various experimental techniques. The 

electronic phase diagram is unique compared to other high-Tc pinctides in that the 

antiferromagnetic ( AF ) phase hardly overlaps the superconducting ( SC ) phase, 

and the optimal doping level is located away from the AF phase boundary. The latter 

feature is common to the R1111 series ( R = Ce, Nd, etc. ). Recently, an exotic phase 

diagram has been obtained in LaFeAsO 1-xH x in which a high Tc is maintained even 

in an overdoping regime, and the second SC dome emerges upon excess H doping. 

To investigate the exotic electronic state on a microscopic level, we performed 75As 

NMR measurements for 20% and 40% doped samples. The former doping level 

corresponds to the boundary between two SC domes, and the latter corresponds to the 

optimal doping level of the second dome. The relaxation rates for 20% doped samples 

are comparable with those of LaFeAsO 1-xF x (x = 14%) , however rates for 40% doped 

samples enhanced at a fixed temperature implying that some spin fluctuations return 

and some magnetic ordering would occur upon excess H doping.

QB24 

Multi-frequency ESR in EuFe2As2 Masami Ikeda 1 , Tatsuya Kobayashi 2 , Wataru Hirata 2 , Shigeki Miyasaka 2 , Setsuko 

Tajima 2 and Masayuki Hagiwara 1 

1 

KYOKUGEN, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, 

Japan 

2 

Dep. of Phys., Faculty of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, 

Osaka 560-0043, Japan 

One kind of the iron based superconductors is called ‘122’ system. Most parent 

materials of the ‘122’ system exhibit a spin-density wave (SDW) transition that 

is accompanied by a structural phase transition [1]. EuFe 2As 2 shows the SDW 

transition at TSDW=190 K, and the large local moment Eu 2+ (S =7/2, L =0) orders 

antiferomagnetically below TN=19 K. Above TSDW, it is believed that Eu 2+ localized 

magnetic moments interact with itinerant electrons. Below TSDW, the interlayer 

interaction turns to be weak and the system becomes anisotropic [2]. To study the 

above natures of EuFe 2As 2 in more details, we have performed multi-frequency (20- 

35 GHz) electron spin resonance (ESR) measurements. Above TN, the resonance 

signal can be fitted with the Dysonian function, and the temperature dependence of the 

linewidth obtained by this fitting obeys the Korringa relation above TSDW as observed 

at X-band ESR [2]. From this relation, we will discuss the exchange interaction 

between Eu 2+ moments and conduction electron spins. 

[1]Y. Xiao et al., Phys. Rev. B 80 (2009) 174424. [2]E. Dengler et al., Phys. Rev. B 81 (2010) 

024406. 

QB25 

Analysis of the critical current density and flux pinning properties in 

iron-based Ba 0.55K 0.45Fe 2As 2 high T c superconductor 

Dawood Ahmad 1 , I S Park 1 , G C Kim 1 , Rock Kil Ko 1,2 , J H Lee 1 , and Y C Kim 1 

1 Department of Physics, Pusan National University, Korea 

2 Korea Electrotechnology Research Institute, Changwon 641-120, Korea 

The critical current density and flux pinning properties of the Ba 0.55K 0.45Fe 2As 2 high 

Tc superconductor with T c = 37K are studied using field and time dependence of 

the magnetization. The temperature dependence of the critical current density J c(T) 

have been found to follow the form J c ∝ (1-T/T c ) n and is consistent with δ T c type 

pinning due to the randomly distributed defects larger than the coherence length ξ. 

The temperature dependence of the magnetic relaxation rate S exhibits a peak at 

much lower temperature which corresponds to the smaller pinning energy in the 

Ba 0.55K 0.45Fe 2As 2 superconductor. Moreover, the effective pinning potential U o increases 

with the increase in temperature this behavior is in agreement with those of high T c 

cuprate superconductors. 

QB26 

In-plane anisotropy of magnetic and electric properties of the Fe 

pnictide Ba(Fe 1-xCo x) 2As 2 

Yoshiaki Kobayashi 1 *, Akihiro Ichikawa 1 , Masayuki Itoh 1 and Masatoshi Sato 2 


2 Research Center For Neutron Science And Technology, CROSS, Japan 

The anisotropy of electronic and magnetic properties within FeAs-planes of Co(2%)doped 

BaFe 2As 2 was investigated by 75As-NMR measurements of the As sites As0 

with all four nearest neighbor sites occupied by Fe. Interestingly, even in the tetragonal 

phase (T >100 K), two sets of NMR spectra with two fold symmetry of in-plane 

Knight shifts and electronic nuclear quadrupole frequencies were observed. They 

originate from the existence of two domains with their symmetry axes lying at rightangles 

to each other. The anisotropy of the electronic and magnetic properties become 

pronounced on cooling at ~140 K, below which the in-plane anisotropy was reported to 

appear for the electrical resistivity under the pressure along one of Fe-Fe directions [1]. 

75As-NMR was also carried out at the As site As1 surrounded by one Co and three Fe. 

From the data, we can see that the spin susceptibility at As1 is ~1/3 of the value at As0 

and that the antiferromagnetic spin fluctuation at As1 is fairly suppressed as compared 

with the value at As0. We discuss these behaviors of the FeAs layer in connection with 

the impurity-induced local orbital ordering suggested by the theoretical studies. 

[1] J.-H. Chu, J. G. Analytis, K. D. Greve, P. L. McMahon, Z. Islam, Y. Yamamoto and I. R. Fisher 

:Science 329 (2010) 824. 

QB27 

Vortex tunneling spectra of iron-pnictide superconductors 

Yuhei Kikuchi* and Hiroki Tsuchiura 

Applied Physics, Tohoku University, Japan 

QB28 

QB29 


Symmetry and structure of the superconducting gap functions in iron-pnictides have 

been still under spirited debate. Quasi-particle states around surfaces/interfaces or 

impurities have played a crucial role for identifying the gap functions in several 

unconventional superconductors such as cuprates or Sr 2RuO 4. However, the gap 

symmetry of iron-pnictide is believed to be s-wave, and the point at issue is to identify 

whether the gap structure has inter-band sign reversal (s+-) or not (s++). Thus, it 

will be difficult to distinguish these gap structures based on surfaces/interfaces 

information. There exist several studies on impurity-induced states in iron-pnictides. 

However, because of the complex band-structures of such systems, theoreticalmodeling 

of impurities in iron-pnictide is not free of ambiguity. Vortex core states can 

be another “probe” to identify the gap symmetries and structures in unconventional 

superconductors. Since a vortex core is not a chemical substance, there are no 

ambiguities in theoretical modeling. Thus, in this work, we theoretically study the 

quasi-particle states induced around a vortex core in iron-pnictides using two- or five- 

band effective two-dimensional lattice models [1][2] within the Bogoliubov-de Gennes 

theory. We will also examine the impurity-induced quasi-particle states, and discuss the 

relation between present results and recent STM/S experimental results. 

[1]T. Kariyado and M. Ogata, J. Phys. Soc. Jpn. 79, 083704 (2010). [2]S. Raghu et al., Phys. Rev. B 

77, 220503 (2010). 

Direct observation of superconducting gaps and their anisotropies in 

Ba 1-xK xFe 2As 2 

Y. Ota 1 *, K. Okazaki 2 , Y. Kotani 2 , T. Shimojima 3 , T. Kiss 4 , C. - T. Chen 5 , S. Watanabe 6 , K. Kihou 7 , C. H. Lee 7 , A. 

Iyo 7 , H. Eisaki 7 , T. Saito 8 , H. Fukazawa 9 , Y Kohori9 and S. Shin 10 

1 ISSP, Japan 

2 ISSP, JST-CREST, Japan 

3 Univ. of Tokyo, Japan 

4 Osaka Univ., Japan 

5 CAS, China 

6 Tokyo Univ. of Sci., Japan 

7 AIST, JST-TRIP, Japan 

8 Chiba Univ., Japan 

9 JST-TRIP, Chiba Univ., Japan 

10 ISSP, JST-CREST, JST-TRIP, RIKEN, Japan 

Among the iron-pnictides, (Ba,K)Fe 2As 2 (BaK122) system is the most interesting: while the 

optimally-doped BaK122 has a full gap (no node in the superconducting(SC) gap), the extremely 

hole-doped KFe 2As 2 (K122), which has no electron pocket, has been suggested to have SCgap 

nodes from several experiments. From the previous studies of laser-excited angle-resolved 

photoemission spectroscopy (laser ARPES), the optimally doped BaK122 has no anisotropy and 

Fermi surface (FS) sheet dependence in SC-gap sizes on the three hole FS around the Brillouin 

zone center. On the other hand, we found that K122 has clear anisotropies and sheet dependence. 

In addition, we found that the middle hole FS has eight nodes and identified their Fermi momenta. 

It should be important to investigate doping dependence of anisotropies and FS-sheet dependence 

of SC-gap sizes, and node existence to clarify the paring mechanism at each doping level. We have 

directly observed superconducting gaps and their anisotropies in the overdoped BaK122 utilizing 

laser ARPES. We will discuss these results and contrast them with other experimental and theoretical 

results available in literature. 

Contrasting superconducting property in Fe-based superconductors 

(Ca4Al2O6-y)(Fe2Pn2)[Pn=As and P] 

Hiroaki Kinouchi 1 , Hidekazu Mukuda 1 , Mitsuharu Yashima 1 , Yoshio Kitaoka 1 , Chulho 

Lee 2 , Parasharam M. Shirage 2 , Hiroshi Eisaki 2 and Akira Iyo 2 

1 

Department of Materials Engineering Science, Graduate School of Engineering 

Science, Osaka University, Japan 

2 

National Institute of Advanced Industrial Science and Technology (AIST), Japan 

We report As-nuclear quadrupole resonance (NQR) study on (Ca 4Al 2O 6-y)(Fe 2As 2) with 

Tc=27K, and P-nuclear magnetic resonance (NMR) study on (Ca 4Al 2O 6-y)(Fe 2As 2) with 

Tc=17K. (Ca 4Al 2O 6-y)(Fe 2As 2) possesses the characteristic structural parameters such as short 

a-axis length, high pnictgen height, narrow As-Fe-As angle, and thick perovskite-type blocking 

layer. A measurement of the nuclear spin relaxation rate 1/T1 revealed a significant evolution of 

antiferromagnetic (AFM) spin fluctuations in normal state, which originates from the possible 

well nested hole and electron Fermi surfaces. Below Tc, the 1/T1 decreases steeply upon cooling 

without any trace of Hebel-Slichter peak, which is consistently accounted for within the framework 

of nodeless s(+-)-wave multiple gap model. On the other hands, (Ca 4Al 2O 6-y)(Fe 2As 2) is 

characterized by lower pnictgen height and wider As-Fe-As angle than that of (Ca 4Al 2O 6-y)(Fe 2As 2), 

where FeP_4 forms nearly regular tetrahedron. The P-NMR- 1/T1 measurement revealed the 

presence of AFM spin fluctuations in normal state and gapless SC state. These facts indicate the 

close relationship between the local structural characters of FePn_4 and the SC properties. 

H. Kinouchi, H. Mukuda, M. Yashima, Y. Kitaoka, P. M. Shirage, C-H. Lee, H. Eisaki, and A. Iyo 


Poster Tuesday



QB30 

Superconducting properties of FeTe 1-xSe x single crystals: impact of 

disorder and hydrostatic pressure 

Roman Puzniak*, Dariusz J. Gawryluk, Marek Berkowski, Piotr Dluzewski, Jaroslaw 

Pietosa, Aleksander Wittlin and Andrzej Wisniewski 

Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02-668 

Warsaw, Poland 

It was found that chemical and structural disorder in superconducting single crystals 

of Fe(Te,Se), originating from kinetics of crystal growth process, strongly influences 

superconducting properties. The sharpness of a transition to the superconducting state is 

evidently inversely correlated with crystallographic quality. Ions inhomogeneous spatial 

distribution seems to enhance the superconductivity and inhomogeneous distribution of 

host atoms might be an intrinsic feature of superconducting chalcogenides. Small disorder 

introduced into magnetic sublattice, by partial replacement of Fe ions by slight amount 

of nonmagnetic ions of Cu or by magnetic ions of Ni and Co with spin value different 

than that of Fe ion, completely suppresses superconductivity. Even if superconductivity is 

observed in the system containing magnetic ions it can not survive when the disorder in 

magnetic ions sublattice is introduced. We have found pressure-induced enhancement of 

all of the superconducting state properties of FeTe 0.5Se 0.5 single crystals, which entails a 

growth of the density of superconducting carriers. We noticed more pronounced increase 

in superconducting carrier density under pressure than that in the critical temperature what 

may indicate an appearance of a mechanism limiting the increase of Tc with pressure. The 

critical current density increases under pressure by at least one order of magnitude. 

QB31 

The influence of superconductivity with magnetism in superconductor/ 

magnetic heterostructures 

Jeehoon Kim*, R. Baumbach, N. Haberkorn, J. Lee, L. Civale, Q. Jia, A. J. Taylor, E. 

Bauer, J. D. Thompson and R. Movshovich 

Los Alamos National Laboratory, USA 

Interplay between superconductivity and magnetism continues to be one of the 

central themes in Condensed Matter Physics. We have investigated a variety of 

superconductor/ferromagnetic heterostructures, such as YBCO/LSMO, Nb/GCMO, 

and Nb/CeRu 2Al 2B using low temperature magnetic force microscopy, addressing 

mainly magnetic pinning and domain wall superconductivity. In YBCO/LSMO, we 

focused on the critical state and observed effects of magnetism on superconductivity. 

In Nb/GCMO, we found that magnetic domains provide weak pinning centers, and 

act as magnetic templates. A recently discovered CeRu 2Al 2B system shows a variety 

of magnetic phases such as antiferromagnetic, ferromagnetic, and ferrimagnetic 

domains in the field/ temperature plane. We will discuss how we can manipulate 

superconducting domains in superconducting film (Nb) via these magnetic phases in 

close proximity. 

QC01 

The influence of the magnetic moment on the atomic distance in 

amorphous CexRu 100-x 

Yingjie Li 1 , Nakai Ikuo 2 *, Amakai Yusuke 3 and Shigeyuki Murayama 3 

1 1Inner Mongolia Key Laboratory for Physics and Chemistry of Functional 

Materials, Physics and Electronic Information College, Inner Mongolia Normal 

University, Hohhot 010022, China 

2 Department of Electrical and Electronic Engineering, Graduate School of 

Engineering, Tottori University,Tottori 680-8552, Japan 

3 Department of Materials Science and Engineering, Muroran Institute of Technology, 

Hokkaido 050-8585, Japan 

The extended x-ray absorption fine structure (EXAFS) measurement was performed 

in amorphous alloys CexRu 100-x (x=9, 43 and 80). We found that the Ce-Ce interatomic 

distance increases with increasing the Ce content while those of Ce-Ru and Ru-Ru 

pairs are unchanged and that the Ce-Ce interatomic distance is exactly proportional 

to the Ce effective magnetic moment. We discuss the relation between the Ce-Ce 

atomic distance and the effective magnetic moment 1) from the point of view of the 

magnetovolume effect. 

1) Y. Amakai et al., J. Phys. : Conf. Ser. 150 (2009) 042004. 


QC02 

Theoretical studies of the superconductivity and antiferromagnetism 

coexistence and the divergence of effective electron mass near quantum 

critical point in CeRhIn 5 

Valery V. Val'kov and Anton O. Zlotnikov 

Laboratory of Theoretical Physics, L.V. Kirensky Institute of Physics, Russia 

Competition and coexistence of superconductivity and antiferromagnetism have been studied in the framework 

of the periodic Anderson model taking into account the superexchange interaction between localized 4f 

electrons. It has been shown that pressure-induced energy change of the localized states leads to modifying 

antiferromagnetic and superconducting order parameters. This modification of the order parameters develops 

in such way that a strong competition is suggested between antiferromagnetism and superconductivity. It has 

been proposed that the energy increase is caused by pressure growth. In spite of the competition mentioned 

above, conditions have been found for the coexistence of superconductivity and antiferromagnetism in the 

model. Theoretical results of the pressure effects on the ground state character of the heavy-fermion systems 

are in good agreement with specific heat data for CeRhIn 5 [1, 2]. In the coexistence phase there occur two 

types of Cooper pairing due to the antiferromagnetic exchange field. The divergence of the effective electron 

mass produced by suppressing antiferromagnetic order has also been analyzed in the same framework. Further 

it has been shown that at quantum critical point there occurs the transition from small to large Fermi surface. 

Such features have been found in the de Haas-van Alphen experiments for CeRhIn 5 [3]. 

1. H. Hegger, C. Petrovich, E.G. Moshopoulou, M.F. Hundley, J.L. Sarrao, Z. Fisk, J.D. Thompson, 

Phys. Rev. Lett. 84, 4986 (2000). 2. T. Park, J.D. Thompson, New Journal of Physics 11, 055062 

(2009). 3. H. Shishido, R. Settai, H. Harima, Y. Onuki, J. Phys. Soc. Jap. 74, 1103 (2005). 

QC03 

Josephson effect between UPt 3 and Nb under pressure 

Akihiko Sumiyama 1 *, Jun Gouchi 1 , Gaku Motoyama 1 , Akira Yamaguchi 1 , Noriaki 

Kimura 2 , Etsuji Yamamoto 3 , Yoshinori Haga 3 and Yoshichika Onuki 4 

1 Univ. of Hyogo, Japan 

2 Tohoku Univ., Japan 

3 JAEA, Japan 

4 Osaka Univ., Japan 

The heavy-fermion compound UPt 3 is an odd-parity superconductor and possesses a complex 

field-temperature (H-T) phase diagram with three phases: A (low H and high T), B (low H and 

low T) and C (high H and high T) phases. We have investigated the Josephson effect between UPt 3 

and Nb and observed an anisotropic temperature dependence of Josephson critical current Ic at 

the transition from A to B phases[1]. However, the Josephson effect, which is easily destroyed by 

a small magnetic field, has not been measured in C phase. Considering that C phase appears even 

in zero field by applying pressure[2], we have investigated the pressure dependence of Josephson 

effect together with resistance and Meissner effect of UPt 3. The superconducting transition occurs 

at lower temperature and becomes broader by applying pressure. As the pressure is increased, the 

Josephson effect appears at lower temperature than the zero-resistivity temperature of UPt 3, while 

Ic increases more rapidly; the increasing rate -dIc/dT is a linear function of pressure. Although 

the Josephson effect in C phase has been observed for the first time, an abrupt change in the 

temperature dependence of Ic caused by the transition to C phase has not been found yet. 

[1] A. Sumiyama et al.: Phys. Rev. Lett. 81 (1998) 5213; A. Sumiyama et al.: Jpn. J. Appl. Phys. 

Series 11 (1999) 47. [2] M. Boukhny et al. : Phys. Rev. Lett. 73 (1994) 1707. 

QC04 

Hidden order in URu 2Si 2 --- Analysis based on the first-principles 

approach 

Hiroaki Ikeda 1 *, Michi-to Suzuki 2 , Ryotaro Arita 3 , Tetsuya Takimoto 4 , Takasada 

Shibauchi1 and Yuji Matsuda 1 

1 Department of Physics, Kyoto university, Japan 

2 CCSE, Japan Atomic Energy Agency, Japan 

3 Department of Appliced Physics, University of Tokyo, Japan 

4 Asia Pacific Center for Theoretical Physics, POSTECH, Korea 

The so-called 'hidden-order' phase transition at $T_{HO}=17.5$K in the heavy-electron metal 

URu 2Si 2, specified by a clear jump in the specific heat measurement, is a long-standing mystery 

in the condensed-matter physics since the discovery in 1985. In spite of every effort, it remains 

still dark what kind of symmetry is broken below $T_{HO}$. So far, there are no evidence 

for magnetic/structural and any low-rank multipole orders. Recent advanced angle-resolved 

photo-emission spectroscopy indicates that $5f$ electrons appears to be itinerant rather than 

localized. Thus, the detailed analysis of the complicated band structures including the spinorbit 

coupling has been strongly desired. We show here the first report of the complete set of 

itinerant multipole correlations up to the fifth rank within the random-phase approximation and 

beyond. The itinerant Hamiltonian is obtained by the advanced Wannier method from the firstprinciples 

calculations. From the most divergent correlations, we obtain nearly degenerate two 

staggered-ordered states of rank-1 dipole with $A_2^-$ and rank-5 dotriacontapole with $E^- 

$; the former corresponds to the antiferromagnetic state realized under high pressures, and the 

latter the hidden-order state. This novel high-rank electronic state provides natural explanations 

of the key features for the hidden order including spontaneous fourfold symmetry breaking.

QC05 

Sb NQR study of filled skutterudite CeFe 4Sb 12 synthesized under high 

pressure 

Ko-ichi Magishi 1 *, Hitoshi Sugawara 2 , Masahiro Takahashi 1 , Takahito Saito 1 , 

Kuniyuki Koyama 1 , Takashi Saito 3 , Sho Tatsuoka 3 , Kenya Tanaka 3 and Hideyuki Sato 3 

1 Institute for Socio-Arts and Sciences, The University of Tokushima, Japan 

2 Graduate School of Science, Kobe University, Japan 

3 Graduate School of Science, Tokyo Metropolitan University, Japan 

Among filled skutterudites, the influence of the filling fraction of R ion on the 

physical properties has been argued, especially in Sb-based filled skutterudites with 

a large pnictogen cage. On RFe 4Sb 12 system, the drastic effect of the R-site vacancy 

on the basic properties has been pointed out. Recently, it has been reported that 

CeFe 4Sb 12synthesized under high pressure (HP) in order to increase the Ce-site filling 

fraction shows the semiconducting transport property at low temperatures, in contrast 

that the sample synthesized under ambient pressure (AP) shows the metallic behavior. 

At the presentation, we report on the result of the Sb NQR measurements for the HP 

sample of CeFe 4Sb 12, and compare with that for the AP sample in order to understand 

the influence of the Ce-site filling fraction. In the high temperature range, the nuclear 

spin-lattice relaxation rate for the HP sample decreases on cooling, and follows the 

exponential decrease above 100 K with the energy gap of 270 K. The value of the 

gap for the HP sample is larger than that for the AP sample, which suggests that the 

hybridization is enhanced by increasing the Ce-site filling fraction. More detailed 

results and analyses will be presented at the conference. 

QC06 

High-mobility magnetotransport of the narrow-gap semiconductor 

FeSb 2 

Hidefumi Takahashi*, Ryuji Okazaki, Yukio Yasui and Ichiro Terasaki 

Department of Physics, Nagoya University, Japan 

Recently, a huge Seebeck coefficient S (-45 mV/K at 10 K) was reported for singlecrystalline 

FeSb 2 samples. Such a huge value seems beyond conventional semiconductor 

physics, indicating a novel mechanism to enhance the Seebeck coefficient such as a strong 

electron correlation expected in so-called 'Kondo insulators'. We study the magnetotransport 

properties of FeSb 2 single crystals to investigate its electronic state at low temperatures[1]. 

The conductivity tensor is well analyzed using a two-carrier model, leading to proper 

evaluation of the mobility and carrier concentration. The mobility significantly increases 

with decreasing temperature and reaches 28000 cm2/Vs at 4 K. The carrier concentration 

decreases from 1 down to 10-4 ppm/unit cell with decreasing temperature from 30 down 

to 4 K, which is well described by thermal activation with a small gap of 6 meV. We also 

find that the magnetoresistive behavior dramatically changes from positive to negative 

at lower temperatures. The negative magnetoresistance is generally observed in doped 

semiconductors and derives from a weak localization of carriers, indicating a considerable 

impurity level in the electronic structure. Our magnetotransport measurements, as well as 

the impurity-effect study[2], strongly suggest that the low-temperature transport is well 

understood within an extrinsic semiconductor picture with ppm-level impurity. 

[1] H. Takahashi et al. Phys. Rev. B 84, 205215 (2011). [2] H. Takahashi et al. J. Phys. Soc. Jpn. 80, 

054708 (2011). 

QC07 

A possible ferromagnetic quantum critical point in CeFe 1-x Ru xPO 

Tetsuro Nakmura 1 , Takashi Yamamoto 2 , Masanori Matoba 1 , Yasuaki Einaga 2 and 

Yoichi Kamihara 1 

1 Department of Applied Physics and Physico-Informatics, Keio University., Japan 

2 Department of Chemistry, Keio University., Japan 

Many materials have their own magnetic transition temperature, and it is controllable by the application 

of a pressure, field or through chemical substitution. In particular, phase transitions which take place at 

absolute zero are called quantum phase transitions, and the transition point is called a quantum critical 

point. Quantum critical points have attracted much attention since some materials exhibit superconductivity 

in proximity to a magnetic quantum critical point. [1] Both CeFePO and CeRuPO are heavy-fermion 

materials containing Ce 4f-electron’s sublattice inducing Kondo effects. Although CeFePO exhibits no 

magnetic transition down to 0.4 K, CeRuPO is one of rare examples of a ferromagnetic Kondo lattice, 

whose transition temperature is 15 K [2]-[5]. In this study, we synthesized CeFe 1-xRu xPO by a solid 

reaction to quantify a chemical composition which is a boundary between ferromagnetic phase and 

paramagnetic phase indicating the quantum critical point. Electrical resistivity and magnetic susceptibility 

are measured at temperatures from 4 K to 300 K. Furthermore, 57Fe Mossbauer spectroscopy was applied 

to CeFe 1-xRu xPO to confirm the ordering of the magnetic sublattice. Our results tentatively indicate that 

CeFe 1-xRu xPO is heavy-fermion metal, and the magnetic quantum critical point exists at x~0.15. 

1) A. J. Millis: Phys. Rev. B 48 7183 (1993). 2) E. M. Bruning, C. Krellner, M. Baenitz, A. Jesche, F. Steglich, 

and C. Geibel: Phys. Rev. Lett. 101 117206 (2008). 3) S. Kitagawa, H. Ikeda, Y. Nakai, T. Hattori, K. Ishida, Y. 

Kamihara, M. Hirano, and H. Hosono: Phys. Rev. Lett. 107 277002 (2011). 4) Y. Kamihara, H. Hiramatsu, M. 

Hirano, H. Yanagi, T. Kamiya and H. Hosono: J. Phys. Chem. Solids. 69 2916 (2008). 5) C. Krellner, N. S. Kini, E. 

M. Bruning, K. Koch, H, Rosner, M. Nicklas, M.Baenitz, and C.Geibel: Phys. Rev. B 76 104418 (2007). 

QC08 

QC09 

QC10 


Ru doping evolution of magnetic properties in Ce(Fe 1-xRu x)PO studied 

by 31P-NMR 

Shunsaku Kitagawa 1 *, Yusuke Nakai 2 , Kenji Ishida 1 , Hiroaki Ikeda 3 , Kensuke Iritani 4 , 

Masanori Matoba 4 , Youichi Kamihara 4 , Masahiro Hirano 5 and Hideo Hosono 6 

1 Department of Physics, Kyoto University JST-TRIP, Japan 

2 Department of Physics, Kyoto University JST-TRIP *present address Graduate School of Science, 

Tokyo Metropolitan Univers, Japan 

3 Department of Physics, Kyoto University, Japan 

4 Departments of Applied Physics and Physico-Informatics, Keio University, Japan 

5 Frontier Research Center, Tokyo Institute of Technology, Japan 

6 Frontier Research Center, Materials and Structures Laboratory, Tokyo Institute of Technology, Japan 

CeFePO and CeRuPO have the same layered crystal structure as iron pnictide superconductors RFeAs(O 1-xF x) (R: 

rare earth). CeFePO is a paramagnetic down to 80 mK and possesses a large Sommerfeld coefficient gamma ~ 

700 mJ/mol K2 at low temperatures, indicating that CeFePO is a heavy fermion compounds originated from Ce 

4f electrons[1]. On the other hand, CeRuPO is a ferromagnetic Kondo lattice system with TCurie = 15 K and 

coherent temperature TK ~ 10 K[2]. We have performed 31P-NMR on Ce(Fe 1-xRu x)PO system to investigate 

the evolution of magnetic properties at low temperatures. Knight shift and spin-lattice relaxation rate 1/T1 

shows extremely large anisotropy. In CeFePO, we found a metamagnetic transition at around mu0H = 4 T and 

below 5 K characterized by the sudden increase in Knight shift when fields are applied perpendicular to the c 

axis[3]. As far as we know, this is the first example of the metamagnetic behavior in a heavy fermion observed 

with XY spin anisotropy. Moreover, Ce(Fe 0.75Ru 0.25)PO shows ferromagnetic ordering at ~ 3 K with strong two 

dimensional ferromagnetic fluctuations. We will show the phase diagram in Ce(Fe 1-xRu x)PO and discuss how 

two dimensional ferromagnetic fluctuations are changed with the Ru doping. 

[1] E. M. Bruning et al., Phys. Rev. Lett. 101, 117206 (2008). [2] C. Krellner et al. J. Cryst. Growth 

310, 1875 (2008). [3]S.Kitagawa et al., Phys. Rev. Lett. 107, 277002 (2011). 

Determining the orientation of the 4f ground state orbital in CeCu2Si2 with vector q dependent non-resonant inelastic X-ray scattering (NRIXS). 

Thomas Willers 1 *, Fabio Strigari 1 , Yong Cai 2 , Nozomu Hiraoka 3 , Ku-ding Tsuei 3 , Yen-fa Liao 3 , Maurits Wim 

Haverkort 4 , Silvia Seiro 5 , Christoph Geibel 5 , Frank Steglich 5 , Liu Hao Tjeng 5 and Andrea Severing 1 

1 

Institute of Physics II, University of Cologne, Germany 

2 

Brookhaven National Laboratory, USA 

3 

National Synchrotron Radiation Research Center, Hsinchu, Taiwan 

4 

Max Planck Institute for Solid State Research, Stuttgart, Germany 

5 

Max Planck Institute for Chemical Physics of Solids, Dresden, Germany 

WITHDRAWN 

Possible superconducting fluctuation in pressure-induced heavyfermion 

superconductor CeRhSi 3 

Noriaki Kimura*, Tetsuya Sugawara, Hiroki Iida and Haruyoshi Aoki 


CeRhSi 3 is a heavy fermion antiferromagnet whose transition temperature is 1.6K. 

The itinerant f electron is thought to be responsible for the magnetism in this material. 

Application of pressure suppresses the magnetism and simultaneously induces 

the superconductivity. At pressures from 0.2GPa to 2.4GPa, the superconductivity 

coexists with the antiferromagnetism. In this pressure region, a broad drop of the 

electrical resistivity and weak shielding in the ac-susceptibility are observed at the 

superconducting transition temperature. We argue a possibility of the superconducting 

fluctuation realized in the coexisting region of the superconductivity and 

antiferromagnetism. 


Poster Tuesday



QC11 

Thermoelectric power in a single-crystalline CeRhSi 3 

Hidekazu Tanaka 1 *, Naofumi Aso 2 , Yoshinao Takaesu 1 , Masato Hedo 2 , Takao 

Nakama 2 , Hiroki Iida 3 , Noriaki Kimura 3 and Haruyoshi Aoki 3 

1 Graduate School of Engineering and Science, University of the Ryukyus, Japan 

2 Faculty of Science, University of the Ryukyus, Japan 

3 Graduate School of Science, Tohoku University, Japan 

CeRhSi 3 is a non-centrosymmetric heavy fermion superconductor.[1] The a- and c-axis 

thermoelectric power S_a and S_c of a single-crystalline CeRhSi 3 were measured under 

pressure up to around 2.7 GPa in the temperature range from 1.5 K to 300 K. Both S_a 

and S_c exhibit a large positive value up to around 60 μV/K, which is characteristic of 

heavy-fermion systems. S_a and S_c show a maximum in its temperature dependence 

due to the Kondo effect and its maximum temperature T_Smax gradually moves to 

higher temperatures from about 90 K (at ambient pressure) to about 130 K (at 2.7 

GPa) by applying the pressure. In both directions, such behaviors of thermoelectric 

power are very similar to those in the CeIrSi 3.[2] In the conference, we will discuss 

the anisotropy of the thermoelectric power in connection with the superconductivity in 

CeRhSi 3. 

[1] N.Kimura et al., Phys. Rev. Lett. 95 (2005) 247004. [2] Y.Takaesu et al., J. Phys. Soc. Jpn. 80 

(2011) SA068. 

QC12 

Valence of CeM2Al10 (M=Ru, Os, and Fe) determined with hard X-ray 

photo emission spectroscopy (HAXPES). 

Fabio Strigari 1 , Thomas Willers 1 , Ku Ding Tsuei 2 , Yen Fa Liao 2 , Arata Tanaka 3 , K. 

Yutani 3 , Y. Muro 3 , Toshiro Takabatake 3 , Liu Hao Tjeng 4 and Andrea Severing 1 * 

1 

University of Cologne, Germany 

2 


3 

ADSM, Hiroshima University, Japan 

4 


QC13 

WITHDRAWN 

Studies on novel tetragonal Ce 2RhGa 12 heavy fermion compound. 

Ramamoorthi Nagalakshmi 1 *, Sengodan Nallamuthu 1 , Varadharajan Krishnakumar 2 , 

Celine Besnard 3 , Hans Hagemann 4 and Marian Reiffers 5 

1 Physics, National Institute of Technology, Tiruchirappalli, India 

2 Physics, Periyar University, Salem, India 

3 Laboratory of Crystallography, Laboratory of Crystallography, University of Geneva, 24 Quai 

Ernest-Ansermet, CH-1211 Geneva 4, Swit, Switzerland 

4 Physical Chemistry, University of Geneva, Geneva, Switzerland, Switzerland 

5 Physics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice, Slovakia, Slovak 

Single crystals of Ce 2RhGa 12 have been synthesized using Ga flux and their structure was determined by 

single-crystal X-ray diffraction. The Ce 2RhGa 12 crystallizes in the tetragonal P4/nbm space group (No. 

125), which is isostructural to Ce 2PdGa 12, with Z = 2 and lattice parameters a 6.0405 A and c= 15.706 A. 

Data were collected at the Swiss Norwegian Beam Line at the European Synchrotron Facility, Grenoble 

France. Also the Laue diffraction was carried out to confirm the single crystal quality possessing 

tetragonal symmetry. The tetragonal structure of Ce 2RhGa 12 is composed of Ce-Ga and PdGa8/2 layers 

similar to CePdGa 6 [1] . The structure is isomorphous to Ce 2MGa 12 M=(Ni, Cu[2], Pd). Along the c axis 

slabs of edge-sharing rectangular prism of RhGa8 alternates with Ga rich areas in which Ce atoms occupy 

cavities made of Ga atoms. The bulk anti ferromagnetic transition of Ce 2RhGa 12 at 3.5 K is exhibited 

by a big jump up to12 J/mol K. The value of γ above magnetic transition in specific heat measurements 

suggests that it is a heavy-fermion system with γ = 420 mJ mol-1 K-2. The magnetic measurements are in 

progress to confirm the consistency of the ordering temperature and the further studies are in progress. 

1. Robin T. Macaluso, S. Nakatsuji, H. Lee, Z. Fisk, M. Moldovan, D.P. Young, and Julia Y. Chana 

Journal of Solid State Chemistry 174, 296-301(2003) 2. J.Y. Cho, J.N. Millican, C. Capan, D.A. Solokov, M. 

Moldovan, A.B. Karki, D.P.Young, M.C. Aronson, J.Y. Chan, Chem. Mater. 20, 6116-6123(2008) 


QC14 

Electronic structures of plutonium compounds with the NaCl-type 

monochalcogenides structure 

Takahiro Maehira 1 *, Yasutomi Tatetsu 2 and Eijiro Sakai 1 

1 

Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan, 

Japan 

2 

Graduate school of Engineering and Science, University of the Ryukyus , Nishihara, 

Okinawa 903-0213, Japan, Japan 

Some of the uranium and the transuranium compounds are characterized as strongly 

correlated f electron systems and have attracted particular interest because of rich 

variety of anomalous physical phenomena such as the valence fluctuation, the Kondo 

lattice, exotic magnetism, unconventional superconductivity, etc. Among such 

compounds, the plutonium monochalcogenides display a variety of anomalous physical 

properties. For PuX (X=S, Se, Te) have been studied intensively both theoretically 

and experimentally[1,2]. To understand the electronic properties of these materials, 

the features of the ground state should be first clarified. The calculations for the energy 

band structure have been done by using the relativistic linear augmented-plane-wave 

(RLAPW) method. Note here that relativity should be taken into account, because of 

large atomic numbers of the constituent atoms. In the presentation, we try to understand 

what the key issues are to construct the energy band structures around the Fermi energy 

for PuS, PuSe and PuTe. 

[1] A. Hasegawa, and H. Yamagami, J. Magn. Magn. Mater. 104-107, 65 (1992). [2] P. M. 

Oppeneer, T. Kraft, and M. S. S. Brooks, Phys. Rev. B61, 12825 (2000). 

QC15 

Electronic property of ThSn 3 in comparison with uranium and 

transuranium compounds 

Yasutomi Tatetsu 1 *, Takahiro Maehira 2 and Eijiro Sakai 2 

1 Graduate school of Engineering and Science, University of the Ryukyus, Japan 

2 Faculty of Science, University of the Ryukyus, Japan 

Recent rapid expansion of the research frontier of condensed matter physics from 

uranium to transuranium compounds has stimulated renewed attention and much 

interest on exotic properties of actinides and related compounds. It is a challenge to 

modern electronic-structure theory to understand the appearance of a large number 

of exceptionally complicated crystal structures of actinide metal. It is important to 

clarify electronic structure of actinide compounds which exhibit exotic magnetism 

and unconventional superconductivity. By using a relativistic linear augmentedplane-wave 

(RLAPW) method with the one-electron potential in the local-density 

approximation, we investigate energy band structures and the Fermi surfaces of 

transuranium compounds ThSn 3, USn 3, NpSn 3 and PuSn 3. It is found in common 

that the energy bands in the vicinity of the Fermi level are mainly due to the large 

hybridization between 5f and Sn 5p electrons. Thorium contains no occupied 5f states, 

thorium compounds provide good comparative systems for investigating the role of 5f 

electrons. In the presentation, we try to understand what the key issues are to construct 

the energy band structures around the Fermi energy for ThSn 3, USn 3, NpSn 3 and PuSn 3, 

we attempt to unveil 5f electron properties purely originating from actinide atoms. 

QC16 

Multipolar phase transition of the 4f2 nonmagnetic doublet in a caged 

compound PrRh 2Zn 20 

Nagasawa Naohiro 1 , Matsumoto T Keisuke 1 , Wakiya Kazuhei 1 , Onimaru Takahiro 1 , 

Umeo Kazunori 1 , Kittaka Shunichiro 2 , Sakakibara Toshiro 2 and Takabatake Toshiro 1 


2 The University of Tokyo, Japan 

The caged compound PrIr 2Zn 20 with the Pr 3+ ion in the Γ3 doublet ground state exhibits a 

superconducting transition at TSC=0.05K in the presence of an antiferroquadrupolar (AFQ) 

order below TQ=0.11K [1, 2]. The entropy release up to TQ is only 20% of Rln 2 which 

is expected for the Γ3 doublet with the quadrupolar degrees of freedom. It suggests that 

quadrupolar degrees of freedom remain active even below TQ and quadrupole fluctuations 

play an important role in forming the Cooper pair in the superconducting state. In the 

present work, we have focused an isostructural and isoelectronic compound PrRh 2Zn 20. The 

electrical resistivity shows a hysteretic behavior between 140K and 470K, suggesting a firstorder 

structural transition. In spite of the possible structural transition, a Schottky-like peak 

at around 10K in the specific heat and anisotropic behavior of the isothermal magnetization 

at 1.8K indicate the crystalline electric field ground state to be the Γ3 doublet. The specific 

heat exhibits a peak at TQ=0.06K, where the entropy release is evaluated to be only 6% of 

Rln 2. Because of the increment of TQ in the magnetic fields and the anisotropic B-T phase 

diagram, the phase transition at TQ should be an AFQ order. 

[1] T. Onimaru et al., J. Phys. Soc. Jpn. 79 033704 (2010). [2] T. Onimaru et al., Phys. Rev. Lett. 

106 177001 (2011).

QC17 

Crystal growth and low temperature properties of non-centrosymetric 

heavy-fermion comound CeTAl 3 (T = Cu, Ag, Au) 

Christian Franz, Alexander Regnat, Andreas Bauer and Christian Pleiderer 

Department fur Physik, Technische Universitat Munchen, Germany 

For a long time full inversion symmetry was thought to be a precondition for heavyfermion 

superconductivity. The discovery of heavy-fermion superconductivity in 

the antiferromagnetic state of CePt 3Si at ambient pressure and CeRhSi 3, CeIrSi 3 and 

CeCoGe 3 at high pressure contradicted these paradigms. All compounds in this class 

crystallize in a P4mm or subclass crystal structure. Here we report on the single crystal 

growth of CeTAl 3 (T = Cu, Ag, Au) with crystal structure I4mm, being isostructural 

to CeRhSi 3 and CeIrSi 3. High purity elements (>5N) have been used as starting 

materials. A special build image furnace was used for crystal growth. Crystal quality 

was determined by Laue x-ray scattering, x-ray powder diffraction and edx. Low 

temperature properties have been investigated by measurements of bulk properties 

including magnetisation, heat capacity and electrical resistivity. 

QC18 

Enhancement of the hall coefficient under pressure in CeCu 2Si 2 

Shingo Araki 1 *, Naoto Nishiumi 1 , Minami Hayashida 1 , Takafumi Shinohara 1 , Yoichi 

Ikeda 1 , Tatsuo C. Kobayashi 1 , Silvia Seiro 2 , Christoph Geibel 2 and Frank Steglich 2 


2 Max Planck Institute for Chemical Physics of Solids, Germany 

CeCu 2Si 2 is the heavy fermion superconductor discovered in 1979. The unconventional 

superconductivity with Tc ~ 0.6 K at ambient pressure is believed to be mediated 

by antiferromagnetic spin fluctuation around the AFM quantum critical point. 

With increasing pressure, Tc increases to reach the maximum at 4.2 GPa, although 

antiferromagnetic spin fluctuation decreases. The existence of the critical valence 

fluctuation around the critical valence transition is proposed to explain the enhancement 

of Tc under pressure [1]. However, there is no direct evidence to reveal the existence of 

the valence fluctuation. In this study, we investigated the Hall effect on single crystal 

of CeCu 2Si 2 under high pressure. The temperature dependence of the Hall coefficient at 

ambient pressure shows a peak at TmL = 4 K for H // [001] and [100]. In addition, the 

Hall coefficient shows the other peak at T1max for H // [100]. The magnitude of the 

Hall coefficient at TmL increases with increasing pressure and reaches the maximum 

at around 4 GPa, coincident with the enhancement of Tc. We will discuss the relation 

between the enhancement of the Hall coefficient and Tc. 

[1] K. Miyake et al.: J. Phys.: Condens. Matter 19 (2007) 125201. 

QC19 

Saturation moment in the ferromagnetic state of EuB6 Vladimir V. Glushkov 1 *, Alexey V. Bogach 1 , Alexey V. Semeno 1 , Sergey V. Demishev 1 , Vsevolod Yu. 

Ivanov 1 , Nickolay E. Sluchanko 1 , Alexey V. Kuznetsov 2 , Sergey Yu. Gavrilkin 3 , Kirill V. Mitsen 3 , Natalja Yu. 

Shitsevalova 4 , Vladimir B. Filipov 4 , Johan Vanacken 5 and Victor Moshchalkov 5 

1 

Low Temperatures and Cryogenic Engineering Dept., A.M.Prokhorov General Physics Institute of 

RAS, Russia 

2 

National Research Nuclear University MEPhI, Russia 

3 

P.N.Lebedev Physical Institute of RAS, Russia 

4 

I. Frantsevich Institute for Problems of Materials Science NASU, Ukraine 

5 

Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Belgium 

Two consequtive phase transitions featuring the onset of ferromagnetism in europium hexaboride [1-4] are 

commonly associated with percolation in the system of linked magnetic polarons at T_M~15.6 K and with 

long range magnetic ordering below T_C=12.6-13.9 K [1]. However, the recent study of high frequency 

electron spin resonance [5] showed neither magnetic phase separation nor MP formation features in the 

system of localized magnetic moments of Eu 2+ . To shed more light on the nature of ferromagnetism we 

studied the magnetic and thermal properties of the EuB 6 single crystals in pulsed (up to 40 T) and steady 

(up to 9 T) magnetic fields at temperatures 2-40 К. The estimated saturation moment M_{sat}~7.4μ_B is 

found to exceed noticeably the magnetic moment of Eu 2+ ion. The difference is shown to be induced by 

an additional contribution to magnetization due to the formation of intermediate magnetic phase below T_ 

M. The observed renormalization of M_{sat} is discussed in terms of the effects of the spin polarization 

in 5d-band and the short range magnetic ordering in the system of Eu 2+ ions. Support from RFBR 11-02- 

00623 project, Federal Programme “Scientific and Educational Human Resources of Innovative Russia” 

and the Methusalem Funding by the Flemish Government is acknowledged. 

[1] U.Yu, B.I.Min, Phys. Rev. B, v.74, p.094413 (2006). [2] S.Sullow et al., Phys. Rev. B, v.57, p.5860 

(1998). [3] V.V.Glushkov et al., JETP v.105, p.32 (2007). [4] J.Kim et al., Phys Rev B, v.78, p.165120 

(2008). [5] A.V.Semeno et al., Phys Rev B, v.79, p.014423 (2009). 

QC20 

QC21 

QC22 


Magnetization of Tm1-xYbxB12 in strong pulsed and steady magnetic 

fields. 

Alexey Bogach 1 *, Nickolay Sluchanko 1 , Vladimir Glushkov 1 , Sergey Demishev 1 , 

Andrey Azarevich 1 , Vladimir Filipov 2 , Natalia Shitsevalova 2 , Slavomir Gabani 3 , Karol 

Flachbart 3 , Johan Vanacken 4 and Victor Moshchalkov 4 

1 

Low temperature and cryogenic engineering, A.M.Prokhorov General Physics 

Institute RAS, Russia 

2 

Institute for Problems of Materials Science NASU, Ukraine 

3 

Institute of Experimental Physics, Slovak Academy of Sciences, Slovak 

4 

Institute for Nanoscale Physics and Chemistry of KUL, Belgium 

The magnetization of solid solutions Tm 1-xYb xB 12 (00.7. Comparison between the steady and pulsed field magnetization behavior provides 

additional arguments in favor of magnetic nanoclusters formation, short range ordering and 

electron phase separation effects in Tm 1-xYb xB 12. 

Stabilization of ferromagnetism and existence of ferromagnetic 

quantum criticality in UCo 1-xRu xGe system 

Michal Valiska*, Jiri Pospisil, Martin Divis, Jan Prokleska and Vladimir Sechovsky 

DCMP, Charles University, Ke Karlovu 5, 121 16, Prague, Czech Republic 

We have prepared polycrystalline samples of UCoGe doped by Ru on the Co-site about 

nominal stoichiometry UCo 1-xRu xGe where x = 0.01-0.35 with step 0.01 to studied 

the magnetic state and ferromagnetic instability in UCoGe. The whole series of doped 

materials keeps the orthorhombic TiNiSi-type structure. The evolution of the lattice 

parameters well follows Vegard’s law respecting the pure parent UCoGe and URuGe. 

While the UCoGe is well known ferromagnetic superconductor (TC = 2.5 K, TSC = 

0.6 K) the URuGe is paramagnetic down the lowest temperatures. Nevertheless the 

ruthenium doping of UCoGe leads to surprising stabilization of the ferromagnetic 

state when the maximum TC = 8.5 K has been found in 12 % Ru doped sample. The 

further increase of the Ru content destabilizes previous ferromagnetic state and it is 

terminated by ferromagnetic quantum critical point at concentration of 30 % of Ru. We 

have prepared single crystal of the UCo 0.88Ru 0.12Ge and UCo 0.70Ru 0.30Ge for detail study 

of the ferromagnetic state, individual contributions of the U, Co and Ru components to 

total magnetic moment, magnetic anisotropy and destabilization of the ferromagnetism 

in UCoGe in relation to superconductivity. The results are discussed on the basis of the 

change of electronic structure. 

Thermal properties of RB 6 (R-La, Ce, Pr, Nd) 

M. A. Anisimov 1 *, A. V. Bogach 1 , V. V. Glushkov 1 , S. V. Demishev 1 , N. A. Samarin 1 , S. Gavrilkin2, N. 

Yu. Shitsevalova3, A. V. Levchenko3, V. B. Filipov3, S. Gabani4, K. Flachbart4 and N. E. Sluchanko1 

1 Low Temperatures and Cryogenic Engineering Dept., A.M.Prokhorov General Physics Institute of RAS, Russia 

2 P.N.Lebedev Physical Institute of RAS, Russia 

3 Institute for Problems of Materials Science NAS, Ukraine 

4 Institute of Experimental Physics of SAS, Slovak 

Rare earth (RE) hexaborides RB_6 represent a class of compounds with variety of magnetic properties including 

antiferromagnetic (R-Ce, Pr, Nd, Gd, Dy, Tb, Ho), ferromagnetic (EuB_6), intermediate valence (SmB_6) 

and heavy fermion behavior (CeB_6). Here we investigate the heat capacity C_P(T) on the high quality single 

crystals of light hexaborides (R-La, Ce, Pr, Nd) in the wide range of temperatures 2-300K. The data obtained 

allow to estimate correctly (i) the electronic component with γ(LaB_6)~2.4mJ/(mol•K), (ii) contribution from 

quasilocal vibrational mode of R^{3+} ion with Θ_E~119 - 152K, (iii) the Debye-type term from rigid boron 

cage with Θ_D~1160K. Our data also suggest the additional (iv) defect mode component which is provided by 

the contribution of the boron vacancies. The estimated values of residual concentration N_{vac}~1-4% agrees 

with the results of X-ray studies of RB_6 [1], [2]. The analysis of magnetic contribution shows that magnetic 

entropy S=∫ΔC_{mag}/TdT reaches the value corresponding to the ground state of 4f-multiplet in the range 

2-4T_N. Taking into account the results of previous thermal investigations [3] we conclude in favour of the spinpolaron 

formation (see [4], [5] for details) in the paramagnetic vicinity of Neel temperature. 

[1] V.A.Trunov, A.L.Malyshev et al., J. Phys.: Cond. Mat. v. 5, p. 2479 (1993). [2] M.M.Korsukova, V.N.Gurin et al., J. Less- 

Common. Met. v. 117, p. 73 (1986). [3] M.Sera, S.Kobayashi et al., Phys. Rev. B v. 54, p. R5207 (1996). [4] N.E.Sluchanko, 

A.V.Bogach et al., JETP v. 104, p. 120 (2007). [5] M.A.Anisimov, A.V.Bogach, V.V.Glushkov et al., JETP v. 109, p. 815 (2009). 


Poster Tuesday



QC23 

Magnetic penetration depth and skin depth study of superconductivity 

and quantum criticality in Ce 1-xR xCoIn 5 (R=La and Nd) 

H. Kim 1 , M. A. Tanatar 1 , K. Cho 1 , J. Murphy 1 , R. Hu 2 , C. Petrovic 2 and R. Prozorov 1 * 

1 The Ames Laboratory, USA 

2 Brookhaven National Laboratory, USA 

A heavy fermion superconductor CeCoIn 5 shows different responses to Nd- or La- 

substitutions for Ce, with the former inducing long range magnetic order coexisting 

with superconductivity. To understand the origin of the differences, we studied the 

temperature and field dependent in-plane magnetic penetration depth, $\lambda(T)$, 

in single crystals of (Ce,R)CoIn 5 (R=La, Nd). Measurements were performed with a 

tunnel diode resonator down to 50~mK in a dilution refrigerator, in magnetic field up 

to 14 T parallel to the $c$-axis. These low-temperature and high field measurements 

allowed for the exploration for the full domain of superconductivity and quantum 

criticality in the T H phase diagram. Some previously unreported features were observed 

and will be discussed from the point of view of measured differential magnetic 

susceptibility. These measurements bring new insight into the interplay between 

superconductivity and magnetism as well as field-tuned quantum critical behavior of 

doped 115 systems. 

QC24 

Low energy spin excitations in single-crystalline CeCu 2Ge 2 in magnetic 

fields up to 10T 

Astrid Schneidewind 1 *, Michael Loewenhaupt 2 , Oliver Stockert 3 and Enrico 

Faulhaber 1 

1 Helmholtz-Zentrum Berlin fur Materialien und Energie, Germany 

2 IFP, TU Dresden, Germany 

3 MPI-CPfS Dresden, Germany 

CeCu 2Ge 2 is Kondo lattice with a moderately enhanced Sommerfeld coefficient of the 

specific heat γ =140 mJ/molK2. It exhibits antiferromagnetic order below TN = 4.1 K. 

The incommensurate magnetic structure can be explained by the nesting properties of 

the calculated Fermi surface when taking into account an itinerant component of the 

Ce 4f-moments in addition to their local character. We performed low-energy inelastic 

neutron scattering experiments on a 2g single crystal of CeCu 2Ge 2 using the cold threeaxes 

spectrometer PANDA at FRM II. Data were taken at 1.5 K and in magnetic fields 

up to 10T applied perpendicular to the (110/001) scattering plane. At zero field the 

spin excitations show an energy gap of 0.5 meV at the magnetic zone center. Away 

the magnetic excitations become dispersive merging into a band of excitations around 

1 meV. For increasing magnetic fields, the gap energy is lowered indicating opposite 

action of external and internal fields. The results will be discussed in the framework of 

local, crystal-field related, and non-local, spin-wave-like, magnetic excitations. 

QC25 

Magnetization measurements under high pressure on incommensuratecommensurate 

phase transitions on UPd 2Si 2 

Hiroyuki Hidaka, Hideki Igarashi, Yusei Shimizu, Chihiro Tabata, Tatsuya 

Yanagisawa and Hiroshi Amitsuka 

Graduate School of Science, Hokkaido University, Japan 

UPd 2Si 2 has the ThCr 2Si 2-type body-centered tetragonal structure. This compound 

shows an incommensurate-antiferromagnetic (IC-AFM) ordering with a propagation 

vector Q = 0.73c* at 135 K (= TNh), and successively undergoes a simple 

commensurate (C) type-I AFM ordering at 108 K (=TNl). It is known that the phase 

transitions are of second order at TNh and of first order at TNl. In addition, an antiphase 

ordering state (Q = 2/3c*) becomes stable in high magnetic field applied along 

the c-axis. The magnetism of UPd 2Si 2 is phenomenologically well explained in terms 

of the one-dimensional Ising model assuming localized 5f spins, whereas Fermi liquid 

behavior with a moderately large electric-specific-heat coefficient ~ 30 mJ/molK2 is 

also seen at low temperature [1]. In the present study, we have measured magnetization 

of UPd 2Si 2 under high pressure up to 5.5 GPa and high magnetic field up to 7 T in 

order to investigate the duality between the localized and the itinerant features of 

the 5f-electronic states in U compounds. From the results of the magnetization and 

previous resistivity measurements under high pressure [2], we will discuss about the 

5f-electronic states of the compound. 

[1] H. Honma et al., J. Phys. Soc. Jpn. 67 (1998) 1017. [2] H. Hidaka et al, J. Phys.: Conf. Ser. 273 

(2011) 012032. 


QD01 

Fe doping and magnetic field effect in the valence fluctuating heavy 

fermion system α-YbAlB 4 

Kentaro Kuga, Keita Sone, Yosuke Matsumoto, Eoin Conor O'farrell and Satoru 

Nakatsuji 

Institute for Solid State Physics, Japan 

The Yb-based heavy fermion system, α-YbAlB 4, has a noncentrosymmetric 

crystal structure, while the structure of the isostoichiometric system, β-YbAlB 4 is 

centrosymmetric [1]. β-YbAlB4 is a unique example of the Yb based heavy fermion 

systems that shows pronounced non Fermi liquid behaviors and a superconducting 

transition at 80 mK under ambient pressure and field [2,3,4]. On the other hand, 

α-YbAlB 4 at low temperatures is well fit to a Fermi liquid type description. Both α and 

β-YbAlB 4 are valence fluctuating systems with the Yb valence of 2.73 for α-YbAlB 4 

and 2.75 for β-YbAlB 4 [5]. We succeeded in substituting Fe for Al in α-YbAlB 4, 

and found an antiferromagnetic order at 10 K. By a small substitution to α-YbAlB 4, 

we also succeeded in inducing non-Fermi liquid behaviors. The antiferromagnetic 

ordering temperature is suppressed by magnetic field and non-Fermi liquid behaviors 

are induced where the Neel temperature vanishes. In this presentation, we will discuss 

the difference of the two non-Fermi liquid behaviors in Fe doped α-YbAlB 4 showing 

thermodynamic and transport properties. 

[1] R. T. Macaluso et al, Chemistry of Materials 19, 1918 (2007). [2] S. Nakatsuji et al, Nature Physics 4, 

603 (2008). [3] K. Kuga et al, Physical Review Letters 101, 137004 (2008). [4] Y. Matsumoto et al, 

Science 21, 316 (2011). [5] M. Okawa et al, Physical Review Letters 104, 247201 (2010). 

QD02 

Magnetic and electric properties of single crystal SmBaMn 2O 6 

Youichi Maeda 1 *, Shigeki Yamada 1 and Takahisa Arima 2 

1 Yokohama city univercity, Japan 

2 Univercity of Tokyo, Japan 

We have succeeded in growth of single crystals of an A-site ordered perovskite 

manganese oxide, SmBaMn 2O 6, and investigated the magnetic and electric properties. 

Since Sm and Ba ions alternately occupy the perovskite A-site, it is expected that 

the magnetic and electric properties should be anisotropic. Moreover, the anisotropy 

may be modified with the charge orbital ordering. We also found that a peak in 

magnetic susceptibility of polycrystals at about 250 K. The magnetic susceptibility 

of a single crystal shows an anomaly which is accompanied by a hysteresis between 

170 K and 210 K. This anomaly is caused by a rearrangement of charge orbital 

ordering. A clear magnetic anisotropy is observed below this temperature indicating 

that this rearrangement of charge orbital ordering accompanies the simultaneous 

antiferromagnetic spin ordering. Temperature dependence of the dielectric constant 

along the c axis also shows an anomaly at the rearrangement temperature, while no 

clear anomaly is observed for E perpendicular to the c axis. This result is consistent 

with the rearrangement of the stacking of the charge- and orbital-ordered sheets along 

the c axis. 

QD03 

Phase diagram and Eu valence state in EuPtP 1-xAs x 

Masaki Sugishima 1 , Akihiro Mitsuda 1 , Hirofumi Wada 1 *, Masahiko Isobe 2 and Yutaka 

Ueda 2 

1 Department of Physics, Kyushu University, Japan 


EuPtP is known to exhibit two valence order transitions at T 1 = 235 K and T 2 = 190 K 

[1]. At T > T 1, the Eu ions have a single valence state with the mean valence of 2.16. At 

T 2 < T < T 1, the Eu valence state is ordered with the sequence of -Eu 2+ -Eu 2+ -Eu 3+ -Eu 2+ - 

Eu 2+ -Eu 3+ - along the c-axis. Moreover, the stacking is replaced by another sequence 

with -Eu 2+ -Eu 3+ -Eu 2+ -Eu 3+ - below T 2 [2]. Consequently, the successive valence order 

transitions are accompanied by increase in the Eu mean valence upon cooling. The 

substitution of As for P expands the lattice and decreases both T 1 and T 2 [3]. In this 

study, we report a phase diagram and the Eu valence state in EuPtP 1-xAs x. For 0

QD04 

Investigation of crystal structure, magnetism and transport properties 

of SrFe 1-xTi xO 3-δ systems 

Sendilkumar A 1 , Babu P. D. 2 , Manivelraja M 3 , R.reddy V. 4 and Srinath S 1 * 

1 School of Physics, University of Hyderabad, India 

2 UGC-DAE Consortium for Scientific Research, R-5 Shed, B.A.R.C,Mumbai, 400 085,India, India 

3 School of Physics, Advanced Magnetics Group ,DMRL,Hyderabad, 500 046 ,A.P ,India, India 

4 4UGC-DAEF ,Khandwa Road, Indore, 425017, M.P, India, India 

SrFeO 3 has attracted lot of attention in the recent past due to the exciting electric and magnetic properties 

that can be achieved by varying oxygen stoichiometry. In this investigation, partial replacement of Fe 4+ 

with a non-magnetic ion of Ti 4+ in SrFeO 3-δ is carried out to reduce the magnetic complexity of the helical 

structure and determine the resulting chemical and magnetic structure using neutron powder diffraction 

and Mossbauer spectroscopy. Rietveld refinement of the neutron data indicated the presence of 

tetragonal symmetry with I4/mmm space group in δ~0.125. Our neutron and Mossabauer measurements 

confirm that Fe exists in three different sites both crystallographically as well as magnetically in all four 

compositions. oxygen deficient SrFe 1-xTi xO 3-δ (x = 0 to 0.3) show an insulating behavior with a canted 

antiferromagnetic spin ordering, in comparison to a metallic, helical spin arrangement of x=0. Resistivity 

of x = 0 to 0.3 follows the Mott’s 2-dimensional variable range hopping (VRH), ρ= ρ0 exp(T0/T)- 

1/3. The composition dependence of ac conductivity is carried out in the frequency range 40 Hz to 1 

MHz and the cole-cole plots show a single semicircular arc representing the grain contribution. The 

temperature coefficient of resistance (TCR) changes from negative to positive (PTCR) for x = 0.2. 

[1] J.P.Hodges , S.Short, J.D.Jorgensen, X.Xiong,B.Dabrowski, S.M.Mini and C.W.Kimball Journal of Solid State Chemistry 151,(2000) 

190-209. [2] P.K.Gallagher ,J.B.Mac Chesney and D.N.E.Buchanan, The Journal of Chemical Physics 41, 8(1964) 2429. [3] Y.Takeda, 

K.Kanno ,T.Takada, O.Yamamoto, M.Takano, N.Nakayama and Y.Bandol J.Solid State Chemistry 63,(1986) 237-249. [4] M.Takano, T.Okita, 

N.Nakayama, Y.Bando, Y.Takeda, O.Yamamoto and J.B.Goodenough J.Solid State Chemistry 73,(1988) 140-150. [5]A.Lebon, P.Alder, 

C.Bernhard, A.V.Boris, A.V.Pimenov, A.Maljuk, C.T.Lin, C.Ulrich and B.Keimer Phy.Rev.Lett. 92,3(2004) 037202 [6]Peter Alder and Sten 

Eriksson , Z.Anorg. Allg. Chem. 626 (2000) 118-214. [7] S. Srinath, M. Mahesh Kumar, M. L. Post, and H. Srikanth, Phys. Rev. B 72 (2005) 

QD05 

Evolution from a localized to an intermediate valence regime in 

Ce 2Cu 2-xNi xIn 

Adam Pikul* and Dariusz Kaczorowski 


Poland 

Ce 2Cu 2In and Ce 2Ni 2In crystallize in a primitive tetragonal structure of the Mo 2FeB 2 

type. The former compound orders antiferromagnetically at the Neel temperature of 

5.5 K, while the latter one is a system with fluctuating valence [1]. Here we report 

on low temperature physical properties of the solid solution Ce 2Cu 2-xNi xIn studied by 

means of x-ray powder diffraction, magnetic susceptibility and electrical resistivity 

measurements, using polycrystalline specimens. We show that partial substitution 

of Cu by Ni results in a quasi-linear decrease of the lattice parameters and unit cell 

volume of the system. The lattice compression leads to an increase in the exchange 

integral and yields a reversal in the order of the magnetic 4f1 and nonmagnetic 4f0 

states, being in line with the Doniach phase diagram. In the localized regime, where an 

interplay of the Kondo scattering and the crystalline electric field effect occurs, the rise 

in the hybridization strength is accompanied by a relative reduction in the scattering 

conduction electrons on excited crystal field levels. 

[1] D. Kaczorowski, P. Rogl and K. Hiebl, Phys. Rev. B 54 (1996) 9891. 

QD06 

Substitution effect in CeFe 2Al 10 

Takashi Nishioka 1 , Yuta Oogane 1 , Daishi Hirai 1 , Harukazu Kato 1 , Masahiro 

Matsumura 1 , Yukihiro Kawamura 2 and Chihiro Sekine 2 

1 Physics, Kochi University, Japan 

2 Physics, Muroran Institute of Technology, Japan 

CeFe 2 Al 10 is an important reference material as CeRu 2 Al 10 which indicates a 

mysterious phase transition. We have performed the electrical resistivity and magnetic 

susceptibility of substiututed systems, i.e., (Ce,La)Fe 2 Al 10 and Ce(Fe,Co)Ru 2 Al 10 . 

The former system reveals the effect of periodicity and the latter one reveals that of 

electron number. A broad peak, which is attributed to Kondo effect, monotonically 

shifts to higher and lower temperatures with La- and Co-substitution, respectively. 

The electrical resistivity of CeFe 2 Al 10 shows a broad peak at 60 K and sharp increase 

below 15 K. A slight substitution of Ce by La and Fe by Co site remove the broad peak 

and the increase at low temperatures. These results indicate the broad peak is due to 

coherence effect and the increase is due to a semiconducting gap. 

QD07 

QD08 

QD09 


Fermi surface and electronic correlations in a valence fluctuating Eusystem: 

an experimental and theoretical study of EuIr 2Si 2 

Silvia Seiro 1 , Oleg Ignatchik 2 , Violeta Guritanu 1 , Vivien Petzold 1 , Takuya Iizuka 3 , 

Kathrin Gotze 2 , Jorg Sichelschmidt 1 , Shin-ichi Kimura 3 , Horst Borrmann 1 , Jochen 

Wosnitza 2 , Helge Rosner 1 and Christoph Geibel 1 * 


2 High Magnetic Field Laboratory Dresden, Helmholtz Center Dresden-Rossendorf, Germany 

3 Institute for Molecular Science, UVSOR Facility, Okazaki 444-8585, Japan 

Electronic correlations can induce strong changes in electronic states, especially those at the Fermi level. These 

effects are presently the subject of intense theoretical and experimental investigations, especially on Ce- and 

U-based heavy fermion systems as well as on High Tc cuprates. In contrast valence fluctuating Eu-systems 

have yet not been investigated in this respect, although the valence fluctuations of Eu should have a strong 

impact. We have recently grown high quality single crystals of the valence fluctuating compound EuIr 2Si 2 and 

started a thorough investigation of its electronic properties. From previous Moessbauer studies the valence 

v of Eu in EuIr 2Si 2 was reported to decrease continuously with temperature, from v = 2.3 at 300 K to v = 

2.8 below 20 K [1, 2]. Our T-dependent XRD, susceptibility, resistivity, and specific heat measurements on 

these single crystals confirm such a strong evolution of the valence and give insight into global effects of the 

strong correlations. These single crystals allowed the first observation of de Haas-van Alphen oscillations in a 

valence fluctuating Eu-system, as well as the first determination of the optical conductivity in such a system. 

Comparing these results with DFT-based calculations give a deeper insight into the correlation effects. 

[1] B. Chevalier, J.M.D Coey, B. Lloret, and J. Etourneau; J. Phys. C: Solid State Phys. 19 (1986) 4521. [2] S. 

Patil, R. Nagarajan, L.C. Gupta, R. Vijayaraghavan, and B.D. Padalia; Solid State Comm. 63 (1987) 955 

Heat capacity and electrical resistivity of CeNi5-xGex Mariana Zapotokova 1 , Ivan Curlik 2 , Marian Reiffers 3 and Mauro Giovannini 4 

1 

Institute of Experimental physics, Watsonova 47, SK 043 53 Kosice, Slovakia, Slovak 

2 

Centre od Low Temperature Physics, Institute of Experimental Physics, Watsonova 

47, SK 043 53 Kosice, Slovakia, Slovak 

3 

Centre od Low Temperature Physics, Institute of Experimental Physics, Slovak 

Academy of Sciences, Kosice, Slovakia, Slovak 

4 

CNR-SPIN and Department of Chemistry, CNR-SPIN and Department of Chemistry, 

University of Genova I-16146 Genova, Italy, Italy 

Metallic Ce compounds are of great interest for the intriguing physical properties 

associated with the 4f electrons. One notable example of compound intensively studied 

for many years is CeNi 5 crystallizing in the hexagonal CaCu 5 type, which results to 

be a Stoner enhanced paramagnet characterized by a spin fluctuation contribution on 

its transport properties. Here the effect of the Ni/Ge substitution on the ground state 

of CeNi 5 is presented. Several ternary germanides CeNi 5-x Gex (x=0.1, 0.2, 0.5, 0.8) 

were prepared by arc melting method. All the alloys crystallize in the CaCu 5 structure. 

Single phase of the polycrystalline samples was confirmed by X ray diffraction. The 

measurements of resistivity between 2-300 K and heat capacity between 0.4-300 K 

were provided and the results are presented. The resistivity measurements show typical 

metallic behaviour. No phase transition was observed in resistivity and heat capacity 

measurements. 

Antiferromagnetic order in Yb5Rh4Ge10 Kazunori Umeo 1 *, Kenichi Katoh 2 and Toshiro Takabatake 3 

1 

N-BARD, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, 

Japan 

2 

Department of Applied Physics, National Defense Academy, Yokosuka 239-8686, 

Japan 

3 

AdSM and IAMR, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 

739-8530, Japan 

The titled compound has three Yb sites in the tetragonal Sc 5Co 4Si 10-type structure. 

The magnetization process shows strong anisotropy [1]. At 2 K, M (B//a) is saturated 

to 4.5 μB/f.u. in 5 T, whereas M (B//c) increases linearly up to 0.9 μB/f.u. at 5 T. The 

effective magnetic moment for B//a is 4.25 μB/Yb, which is close to the value of 4.53 

μB/Yb expected for the Yb 3+ free-ion [1]. The continuous increase in the specific heat 

down to the lowest measured temperature 2 K suggests a magnetic order below 2 K 

[1]. Therefore, we have measured the temperature dependence of the magnetization 

M, specific heat C and resistivity down to 0.3 K. A cusp in M (B//a) and sharp peak 

in C(T) were observed at 0.5 K, both of which were suppressed by applying magnetic 

fields up to 0.8 T. These findings indicate an antiferromagnetic order at TN = 0.5 K. 

However, the magnetic entropy Sm at TN is only 60 % of Rln 2. This observation 

suggests a heterogeneous mixed valence state where three of five Yb ions in formula 

unit are in trivalent state and the rest two are in divalent state. 

[1] K. Katoh et al., Physica B 373 (2006) 111. 


Poster Tuesday



QD10 

Magnetic field dependence of the resistivity minimum of nanosized YbAl 3 

C. Echevarria-Bonet 1 *, D. P. Rojas 2 , L. Fernandez Barquin 1 , J. C. Gomez Sal 1 , S. N. 

Kaul 3 , B. Coqblin 4 , S. G. Magalhaes 5 and E. Bauer 6 

1 CITIMAC, Universidad de Cantabria, Spain 

2 Departamento de Fisica, Universidad Carlos III de Madrid, Spain 

3 School of Physics and Centre for Nanotechnology, University of Hyderabad, India 

4 Laboratoire de Physique des Solides, CNRS-Universite Paris-Sud, France 

5 Instituto de Fisica, Universidade Federal Fluminense, Brazil 

6 Institute of Solid State Physics, TU Wien, Austria 

Yb-based alloys follow the Doniach phase diagram where the competition between RKKY and Kondo 

interaction plays a predominant role. Among them, a simple cubic compound (Pm-3m) YbAl 3 is a fine example 

of strong electron correlations leading to intermediate valence behavior [1]. Recently, we have investigated 

the effect of crystallite size on the electronic and magnetic properties of the nanometric samples of this 

alloy, prepared by high-energy milling of arc-melted ingots. Milling yields massive quantities of 4f-alloys in 

nanocrystalline (nc-) form with a relatively narrow size distribution [2]. In nc-YbAl 3, the variation of valence is 

due to a modification of the fraction of surface atoms compared to the total number of particles. This affects both 

specific heat and susceptibility data [3]. Here, we present a magnetic field (H)-dependent study of the electrical 

resistivity, ρ, of annealed and pressed pellets of nc-YbAl 3. The XRD Rietveld refinements yield particle sizes 

of maximum ~10 nm whereas slightly smaller values are detected by HRTEM. The results are striking in that 

the physical properties change drastically compared to the bulk [4] and an unexpected minimum in ρ(T) occurs 

around 15 K. With increasing H, the minimum becomes more pronounced and shifts to higher temperatures. 

[1] E. Bauer et al., Phys. Rev. B 52, 4327 (1995). [2] D. P. Rojas et al., J. Phys: Cond. Matter 19, 186214 (2007). [3] 

D. P. Rojas et al., Phys. Rev B 78, 094412 (2008). [4] D. M. Rowe et al., J. Phys. D: Appl. Phys. 35, 2183 (2002). 

QD11 

Electronic states of Eu 4As 3 under high pressure 

Hisao Kobayashi 1 *, Yoshitaka Yoda 2 and Akira Ochai 3 


2 Japan Synchrotron Radiation Institute, Japan 


The mixed valence Eu 4As 3 compound with an anti-Th 3P 4 structure shows the charge ordering 

at 345 K and ambient pressure accompanied by trigonal distortion, which is similar to those in 

Yb 4As 3 and Sm 4Bi 3 [1-3]. The hybridization of a narrow 4f band with broad conduction bands 

is one of the important parameters in these charge-ordering compounds, which is possible to be 

controlled by hydrostatic pressure. We observed the melting of the static charge order at about 

10 GPa and room temperature without structural change using high-pressure X-ray diffraction 

[4]. We have carried out 151Eu nuclear forward scattering (NFS) measurements using 

synchrotron radiation under high pressures at low temperatures to investigate the magnetic 

properties of Eu 4As 3. Clear quantum beats due to magnetic hyperfine field were observed 

in 151Eu NFS spectra at 6 K under pressure up to 14.5 GPa. The results of temperature 

dependences of 151Eu NFS spectra reveal that a magnetic ordering temperature increases 

linearly with pressure up to 10 GPa. Above 10 GPa, the magnetic ordering temperature 

decreases gradually with pressure. Consequently, the pressure dependence of the magnetic 

ordering temperature is related to the melting of the static charge order. 

[1] A. Ochiai, et al., J. Phys. Soc. Jpn. 72, 3174 (2003). [2] A. Ochiai, et al., J. Phys. Soc. Jpn. 59, 

4129 (1990). [3] A. Ochiai, et al., J. Magn. Magn. Mater. 52, 13 (1985). [4] H. Kobayashi, et al., J. 

Phys.: Condens. Matter 20 415217 (2008). 

QD12 

Pressure effect on intermediate valence semiconductor SmB6 : 

11B-NMR 

Kouhei Nishiyama 1 , Gabriel Pristas 2 , Takeshi Mito 1 , Takao Kohara 1 , Slavomir 

Gabani 2 , Marian Reiffers 2 , Yasuhiro Komaki 3 , Mitutane Kokubu 3 , Hideto Fukazawa 3 , 

Yoh Kohori 3 , Nao Takeshita 4 and Natalia Shitsevalova 5 

1 

Graduate school of Material Science, University of Hyogo, Japan 

2 

Institute of Experimental Physics, Slovak Academy of science, Slovak 

3 

Graduate School of Science, Chiba University, Japan 

4 

Nanoelectronics Research Institute, National Institute of Advanced Industrial 

Science and Technology, Japan 

5 

Institute for Problems of Material Science, National Academy of science of Ukraine, 

Ukraine 

The intermetallic compound SmB 6 is one of the most famous compounds in terms of the physics of 

intermediated valence state, heavy Fermion systems and Kondo insulators. Recent high pressure measurements 

of 149Sm nuclear forward scattering and resistivity revealed that a pressure-induced insulator-metal transition 

of SmB 6 is intimately connected with a long-range magnetic order, which has renewed interest in this 

compound. In order to investigate variations of the ground state and magnetic properties in SmB 6, we have 

carried out 11B-NMR measurement under pressure. While our group had reported the results of 11B-NMR 

measurements up to 2.6 GPa with a piston-cylinder type pressure cell, the use of a Bridgman Anvil Cell has 

recently enabled us to perform NMR measurements at higher pressures than 4.5 GPa. Spin-lattice relaxation 

rate 1/T1 above 20 K roughly follows an exponential function of temperature, Exp(-Eg/2kBT), consistent with 

previous reports. 1/T1 between 20 and 100 K increases with increasing pressure, indicating a reduction of the 

insulating gap. We will discuss detailed pressure dependences of the energy gap and the Sm valence. 


QD13 

Magnetic properties of ytterbium fluoride sulfide Yb3F4S2 Masashi Kosaka 1 , Takuya Kobiyama 1 , Hiroko Aruga Katori 2 and Naoki Shirakawa 3 

1 

Graduate School of Science and Engineering, Saitama University, Japan 

2 

Division of Advanced Frontier Applied Physics, Tokyo University of Agriculture and 


3 

Nanosystem Research Institute, National Institute of Advanced Industrial Science 

and Technology, Japan 

The ternary ytterbium fluoride sulfide Yb 3F 4S 2 crystallizes in the tetragonal structure 

with space group I4/mmm. This structure can be described as an alternative stack of 

one layer of YbF 2 and two layers of YbFS along the c-axis. In a previous paper, it was 

suggested that there are two different ytterbium cations (Yb2 +) (Yb 3+ )2(F - )4(S 2- )2 present 

[1]. An anomaly with the long-range magnetic order has not been observed down to 0.4 

K by magnetization measurements, and the magnetic susceptibility exhibits a Curie- 

Weiss behavior above 50 K. However, it has become clear that the estimated value of 

the effective magnetic moment cannot be explained by a model which assumes that 

Yb 2+ and Yb 3+ occupy the two different crystallographic sites. A Schottky anomaly is 

found in the temperature dependence of the specific heat around 1.0 K at zero magnetic 

field. This anomaly is shifted towards higher temperatures with increasing applied 

magnetic field, and a release of the residual entropy is observed simultaneously. 

[1] T. Schleid et al., Z. Anorg. Allg. Chem. 626 (2000) 2429. 

QD14 

Physical properties of the layered oxypnictides (CeO)MnPn; Pn=As, 

Sb 

Morosawa Yasuhiro 1 , Takase Koichi 1 *, Onizawa Manami 1 , Moriyoshi Chikako 2 , 

Kuroiwa Yoshihiro 1 , Watanabe Tadataka 1 and Takano Yoshiki 1 

1 Nihon University, Japan 


Recently, the layered iron oxypnictides (LaO)FePn ; Pn = P, As, Sb, which belong to the tetragonal system, 

have attracted much attention due to the discovery of the superconductors (LaO)FeP [1] and (LaO)FeAs [2]. 

Many efforts have been dedicated to explore the superconductor with the highest transition temperature. 

In this tidal stream, many new materials with different physical properties have been found. In case of 

selection of the cerium atom as a rare earth element, these materials of (CeO)FeP [3], (CeO)FeAs [4], 

(CeO)CoP [5], (CeO)CoAs [6] show the typical metallic properties and the Fermi liquid behaviors at 

low temperature. In these systems, the 3d electrons of the iron and cobalt have finite density of state at 

the Fermi energy, and the cerium atom provides the f electrons as carriers at the same time. Namely, it is 

difficult to know which effects are dominant. In our group, the semiconductor based materials (LaO)MnPn 

have been focused and the substitution effects of the rare earth elements on the physical properties have 

been investigated. (CeO)MnAs and (CeO)MnSb indicate metallic character and the Fermi liquid behaviors 

below 30K and 8 K, respectively due to the valence fluctuation of the Ce f electrons. 

[1] Y.Kamihara et al., PHYSICAL REVIEW B 77, 214515 (2008). [2] Y.kamihara et al., J. AM. CHEM. SOC. 

130, NO. 11, 3296-3297 (2008). [3] Y.Kamihara et al., Journal of Physics and Chemistry of Solids 69 2916- 

2918 (2008). [4] G. F. Chen et al., PHYSICAL REVIEW LETTERS 100, 247002 (2008). [5] C. Krellner et al., 

PHYSICAL REVIEW B 404, 3206-3209 (2009). [6] Rajib Sarkar et al., Phys. Rev. B 82, 054423 (2010). 

QD15 

31P-NMR study of valence fluctuating compound EuPtP 

Takeshi Mito 1 , Koji Nishitani 1 , Takehide Koyama 1 , Koichi Ueda 1 , Takao Kohara 1 , 

Akihiro Mitsuda 2 , Masaki Sugishima 2 and Hirofumi Wada 2 


2 Kyushu University, Japan 

We report the results of the first 31P-NMR measurements on the hexagonal layered 

compound EuPtP. This compound exhibits two valence transitions at T1= 235 K 

and T2= 190 K. Various experiments, including magnetization, Eu Mossbauer, and 

x-ray diffraction measurements [1-5], have been carried out in order to investigate the 

valence transitions so far, however the ordered structures below T1 and T2 have not 

been fully clarified. We observed 31P-NMR signals in all three phases. They show 

anomalies at T1 and T2, and the Knight shift of the 31P-NMR lines reach ~ 20 % at 

low temperatures due to large effective moments of magnetic Eu 2+ ions. Below T2, 

three resonance lines of 31P-NMR were observed, which should reflect local symmetry 

at the P-site. Based on these information obtained from the NMR measurements 

(spectrum and spin lattice relaxation time T1, and so on), we discuss possible ordered 

structures at low temperatures of EuPtP. 

[1] N. Lossau et al., Z. Phys. B 74, 227 (1989). [2] N. Lossau et al., Z. Phys. B 77, 393 (1989). [3] G. 

Michels et al., Z. Phys. B 98, 75(1989). [4] A. Mitsuda et al., J. Phys: Condens. Matter 22, 226003 

(2010). [5] T. Inami et al., Phys. Rev. B 82, 195133 (2010).

QD16 

Magnetic behavior of polycrystalline Eu 5Si 3 compound 

Sujata M. Patil 1 *, P. L. Paulose 2 and E. V. Sampathkumaran 2 

1 Wilson College, Mumbai 400007, India 

2 Tata Institute of Fundamental Research, Colaba, Mumbai 400005, India 

The series R 5X 3 (R= light rare earth and X = Ga,Si,Ge,Sn,Sb), form in Cr 5B 3-type 

tetragonal structure. There are two inequivalent ‘R’ sites in this structure, one of them 

showing a very short distance between rare-earth atoms. Single crystal studies of Ce 5Si 3 

show that metamagnetic transition temperature is different along ‘a’ axis and ‘c’ axis, 

which was attributed to the two inequivalent sites of Ce atoms. Studies of R 5X 3 have 

been extensively reported for different rare earths with exception of Eu 5Si 3. Rietveld 

analysis of x-ray diffraction shows the formation Eu 5Si 3 in the Cr 5Br 3-type tetragonal 

structure (space group I4/mcm). Magnetization display a prominent cusp around 

32K corresponding to antiferromagnetic ordering. Zero field cooled and field cooled 

magnetization is different below 30K, thereby showing a complex magnetic structure. 

Magnetization for applied magnetic fields up to 12 T shows that this sample does not 

undergo metamagnetic transition like that in Ce 5Si 3. Heat capacity shows a peak below 

32K which shifts to lower temperatures upon application of magnetic fields, like in a 

typical antiferromagnet. Specific heat also shows a strong magnetic field dependence 

below 20K, revealing the complex nature of magnetic ordering. 

1. R. Pottgen et. al.Z. Anorganische und allgemeine Chemie, 624, 1998, 945. 2. Y. Ushida, M. 

Kontani, Physica B, 281-282, (2000), 86-87. 3. Y. Ushida et. al. J. Phys. Soc. Japan, 70, (2001) 513. 

4. F. Canepa et al J. Alloys and Comp. 203, (1994) L11. 

QD17 

Valence fluctuation study by using X-ray absorption and emission 

spectroscopies at Yb L3-edge in YbNi 3X 9 (X=Al and Ga) 

Naomi Kawamura 1 , Masaichiro Mizumaki 1 , Hisashi Hayashi 2 , Noriko Kanai 2 , 

Kazuyuki Matsubayashi 3 , Yoshiya Uwatoko 3 , Tetsuro Yamashita 4 and Shigeo Ohara 4 

1 Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Japan 

2 Department of Chemical and Biological Science, Japan Women's University, Japan 


4 Department of Engineering Physics, Nagoya Institute of Technology, Japan 

Quantum criticality of Ce- and Yb-based heavy fermion system has been recently 

discussed from a viewpoint of valence fluctuation [1], thus the estimation of valence 

guides in the solution for several anomalies observed near the quantum critical point 

(QCP). Recently, high-quality YbNi 3X 9 (X = Al and Ga) is newly synthesized [2,3] and is 

desired to investigate the electronic states including the valence state as a heavy fermion 

system. In order to clarify the Yb valence state in YbNi 3X 9, X-ray absorption and emission 

spectroscopies at the Yb L3-edge have been performed at BL39XU of SPring-8. For 

YbNi 3Ga 9, the Yb valence of 2.71 at room temperature almost linearly decreases to 2.60 at 

55 K with decreasing temperature, and then the valence maintains a constant value at 2-55 

K, while the valence of YbNi 3Al 9 is almost trivalent in a temperature range of 2-300 K. 

Moreover, the XES spectra for YbNi 3X 9 give us detail information of Yb electronic states 

by comparison with the result in several Yb-based compounds. 

[1] S. Watanabe, et al., Phys. Rev. Lett. 105, 186403 (2010). [2] S. Ohara, et al., J. Phys.: Conf. Ser. 

273, 012048 (2011). [3] T, Yamashita, et al., J. Phys. Soc. Jpn. 81, 034705 (2012). 

QD18 

Angle-resolved photoemission spectroscopy of mixed-valence Sm1-xYxS Keiichiro Imura 1 *, Tetsuya Hajiri 2 , Masaki Kaneko 2 , Yusuke Nishi 2 , Hiroyuki S. 

Suzuki 3 , Noriaki K. Sato 2 , Takahiro Ito 2 , Masaharu Matsunami 1 and Shin-ichi Kimura 1 

1 

UVSOR Facility, Institute for Molecular Science, Japan 

2 


3 

National Institute for Materials Science, Japan 

It is known that samarium mono-sulfide (SmS) exhibits an insulator-to-metal transition, 

so called Black-to-Golden phase transition, by the application of pressure or by the 

substitution of Sm ions [1,2]. Although extensive studies to investigate the mechanism 

of this transition as well as the ground state of golden phase have been made, the phase 

transition has net been perfectly clarified yet. In this study, we focus on Sm 1-xY xS 

system in order to investigate the electronic structure of these two phases by an angleresolved 

photoemission spectroscopy (ARPES). Single crystals of Sm 1-xY xS (x = 0, 0.17, 

0.33) were grown by the Bridgman technique using a high-frequency induction furnace 

installed in NIMS. Photoemission spectroscopy measurement on these crystals was 

performed at UVSOR-II BL5U end station. The obtained ARPES spectrum of pure 

SmS (x = 0) has an energy gap of about 0.4 eV which is consistent with a previous 

report [3]. This energy gap decreases with increasing x, and the top of the Sm 2+ 4f band 

touches the Fermi level in x = 0.33. This result suggests that the Golden phase induced 

by the yttrium substitution is a mixed-valence state. 

[1] A. Jayaraman, et al., Phys. Rev. Lett. 25 (1970) 1430. [2] L. J. Tao and F. Holtzberg Phys. Rev. 

B 15 (1975) 3842. [3] T. Ito, et al., Phys. Rev. B 65 (2002) 155202. 

QE01 

QE02 

QE03 


Critical behavior of a spin-1 triangular lattice Ising antiferromagnet 

Milan Zukovic* and Andrej Bobak 

Department of Theoretical Physics and Astrophysics, Faculty of Science, P. J. Safarik 

University, Slovakia 

We employ Monte Carlo simulations in order to investigate critical behavior of a 

frustrated spin-1 Ising antiferromagnet on a triangular lattice in the presence of a 

single-ion anisotropy. It has been previously found that no long-range order can exist 

in the system with spin 1/2 [1] but it can occur if the spin is larger than some critical 

value estimated as 11/2 [2]. We demonstrate that even small amount of the singleion 

anisotropy can change this scenario. More specifically, we show that long-range 

order can exist in the low-temperature region even below this critical value, namely 

for spin 1, within a certain range of the single-ion anisotropy strength. At higher 

temperatures we identify another phase of the Berezinsky-Kosterlitz-Thouless type 

characterized by a power-law decay of the spin correlation function. We perform finitesize 

scaling analyses to calculate the correlation decay exponent. Subsequently, we 

estimate the critical boundaries of both phases and plot the phase diagram as a function 

of the single-ion anisotropy strength. This work was supported by the Scientific Grant 

Agency of Ministry of Education of Slovak Republic (Grant No. 1/0234/12). 

[1] G.H. Wannier, Phys. Rev. 79 (1950) 357. [2] Y. Yamada et.al., J. Magn. Magn. Mater. 140-144 

(1995) 1749. 

Selectively diluted triangular lattice Ising antiferromagnet in an 

external magnetic field 

Andrej Bobak*, Michal Borovsky and Milan Zukovic 

Department of Theoretical Physics and Astrophysics, Faculty of Science, P.J. Safarik 

University, Slovakia 

It is well known that the pure Ising model with nearest-neighbor antiferromagnetic 

interactions on a triangular lattice shows no long-range ordering due to a high degree 

of frustration. Dilution of one out of three sublattices with nonmagnetic impurities 

can relieve the geometrical frustration globally and, above a certain dilution threshold, 

the system starts showing long-range magnetic ordering characterized by the secondorder 

phase transitions [1]. Within the effective-field theory with correlations we 

demonstrate that the presence of a finite external field in the selectively diluted system 

can dramatically change its critical behavior. In particular, above a certain field value 

the system starts displaying tricritical behavior, i.e., as the dilution increases the phase 

transition becomes initially of first order and only upon further dilution changes to 

the second order. We confirm the existence of the first-order transition in the region 

of moderate dilution and relatively high fields by Monte Carlo simulations. An Ising 

antiferromagnet on a honeycomb lattice is treated as a special case when one sublattice 

is completely removed by dilution. This work was supported by the Grant VEGA No. 

1/0234/12. 

[1] H. Kaya, A.N. Berker, Phys. Rev. E 62 (2000) R1469. 

Possible magnetic transition observed in S=1/2 kagome 

antiferromagnet volborthite by high field ESR 

Hitoshi Ohta 1 *, Wei-min Zhang 1 , Susumu Okubo 1 , Takahiro Sakurai 2 , Yoshihiko 

Okamoto 3 , Hiroyuki Yoshida 4 and Zenji Hiroi 3 





Due to the recent discovery of model substances, such as ZnCu 3(OH) 6C l2 

(herbertsmithite), Cu 3V 2O 7(OH) 2∙ 2H 2O(volborthite) and BaCu 3V 2O 8(OH) 2(vesignieite), 

S=1/2 kagome antiferromanet has attracted much interest experimentally, and we 

suggested a gapless spin liquid state in vesignieite [W. Zhang et al, J, Phys. Soc. Jpn. 

79 (2010) 023708.]. In this paper we will report on high field ESR results of volborthite 

powder sample. For the spin dynamics volborthite shows the g-shift below around 20 K 

similar to vesignieite [H. Ohta et al., Phys. Status Solidi B 247(2010) 679.]. However, 

it shows two modes at 1.8 K, mode A with a very small gap of about 40 GHz (1.9 K) 

and mode B with no gap. Existence of mode B may suggest the spin liquid state with 

no spin gap at 1.8 K. Moreover, two modes cross at around 4.5 T, which corresponds 

to magnetization anomaly at 4.3 T. Detailed frequency dependence measurement up to 

30 T at 1.8 K shows also new anomaly at 14 T. Possible magnetic transitions at 4.3 and 

14 T will be discussed in connection with recent NMR result on volborthite powder. 

Finally very recent high-filed ESR result using single crystal of volborthite will be also 

presented. 


Poster Tuesday



QE04 

Field-induced staggered moment stabilization in frustrated quantum 

magnets 

Burkhard Schmidt*, Mohammad Siahatgar and Peter Thalmeier 

Max-Planck-Institut fur Chemische Physik fester Stoffe, Germany 

For low-dimensional frustrated magnets, the dependence of the staggered moment 

on a magnetic field is nonmonotonic: For small and intermediate fields, quantum 

fluctuations are gradually suppressed, leading to an increase of the staggered moment 

as function of the field strength. For large applied magnetic fields, the classically 

expected field dependence is recovered, namely a monotonous decrease with increasing 

field strength. The staggered moment is eventually suppressed when reaching the 

fully polarized state at saturation. The quantitative analysis of this behavior is an 

excellent tool to determine the frustration parameter of magnetic compounds. We have 

developed a general finite-size scaling scheme for numerical exact-diagonalization 

data of low-dimensional frustrated magnets, which we apply to the recently measured 

field dependence of the magnetic neutron scattering intensity of Cu(pz) 2(ClO 4) 2 in 

the framework of the S=1/2 two-dimensional J _1-J 2 Heisenberg model. We also apply 

linear spin-wave theory to complement our numerical findings. Our results show 

that Cu(pz) 2(ClO 4) 2 is a quasi-2D antiferromagnet with intermediate frustration J_2/ 

J_1=0.2. A self-consistent RPA theory for the magnetic ordering temperature shows 

that with this ratio the observed reentrant behavior of the latter as function of the 

applied magnetic field can be understood as a consequence of the reduced quantum 

fluctuations as well. 

QE05 

Structural and magnetic properties of single crystals of volborthite 

comprising a distorted spin-1/2 kagome lattice 

Hajime Ishikawa 1 *, Yoshihiko Okamoto 1 , Junichi Yamaura 1 , Hiroyuki Yoshida 2 , 

Gøran J. Nilsen 1 and Zenji Hiroi 1 

1 ISSP, the University of Tokyo, Japan 

2 NIMS, Japan 

In geometrically frustrated magnets, exotic ground states such as a spin liquid 

are expected to realize as a result of competing magnetic interaction. Volborthite 

Cu 3V 2O 7(OH) 2∙2H 2O has drawn attention as a model compound for the distorted spin- 

1/2 kagome antiferromagnet. Previous studies using powder samples showed a peculiar 

magnetic transition at 1 K. Recently, H. Yoshida et al. synthesized a small single 

crystal, and found a structural phase transition at 310 K and two magnetic transitions at 

around 1 K, which have not been observed in powder samples. To clarify the physical 

properties of volborthite at low temperatures, we tried to synthesize a large and highquality 

single crystal and obtained large single crystals of 2.5×1.5×0.1 mm in size as a 

result of improving synthesis conditions. By means of single crystal XRD, we found 

a new crystal polymorph at room temperature which crystallizes in space group C2/ 

c, not in C2/m as reported before. There is a phase transition upon cooling at around 

290 K to an I2/a phase, similar as in the C2/m phase. In this presentation, we show the 

differences of structure and magnetic properties between various polymorphs. 

QE06 

High-field study of multiferroic Ni 3V 2O 8 

Junfeng Wang 1 , Masashi Tokunaga 2 , Zhangzhen He 3 and Koichi Kindo 2 

1 Wuhan National High Magnetic Field Center, China 

2 The Institute for Solid State Physics (ISSP), The University of Tokyo, Japan 

3 Fujian Institute of Research on the Structure of Matter, Chinese Academy of 

Sciences, China 

WITHDRAWN 


QE07 

Gapless spin excitation of the triangular-lattice antiferromagnet 

Hiroki Nakano 1 * and Toru Sakai 2 


2 JAEA, SPring8, Japan 

Two-dimensional frustrated magets including the triangular-lattice antiferromagnet 

(TLA) have attracted much attention. However, a useful method among unbaised 

computational methods is limited to being the numerical-diagonalization method that 

can treat only small systems. In spite of such situation, great efforts have been done for 

studies of the TLA; it is widely believed that the ground state of TLA has a long-range 

order of 120-degree structure. The existence of this order indicates that spin excitation 

is gapless; however, the system size (N) dependence of the singlet-triplet energy 

difference of finite-size clusters shows a peculiarity that a nonzero spin gap seems to 

survive in the extrapolation with respect to N[1]. Under circumstances, we calculate the 

singlet-triplet energy difference of possible all the finite-size clusters up to 39 sites by 

our MPI-parallelized code of the numerical-diagonalization method. The analysis used 

in the study of the spin-gap issue of the kagome-lattice antiferromagnet[2] is applied 

to the TLA. The present examination successfully confirms a gapless spin excitation, 

which is consistent with the existence of the long-range order. 

[1] J. Richter et al.: Phys. Rev. B 70 (2004) 174454. [2] H. Nakano and T. Sakai: J. Phys. Soc. Jpn. 

80 (2011) 053704. 

QE08 

Magnetic properties of the spin-1/2 kagome antiferromagnets: 

vesignieite BaCu 3V 2O 8(OH) 2 and CdCu 3(OH) 6Br 2 

Yoshihiko Okamoto 1 *, Makoto Yoshida 1 , Hajime Ishikawa 1 , Gøran J. Nilsen 1 , 

Hiroyuki Yoshida 2 , Masashi Takigawa 1 and Zenji Hiroi 1 

1 Institute for Solid State Physics, Univ. of Tokyo, Japan 


An ideal model system for the spin-1/2 kagome antiferromagnet has not yet been 

obtained and the search for that is still going on. Here we report the magnetic 

properties of two Cu minerals, vesignieite BaCu 3V 2O 8(OH) 2 and CdCu 3(OH) 6Br 2, both 

of which comprise spin-1/2 kagome lattices. Vesignieite has a nearly isotropic kagome 

lattice and was found to show neither Neel order nor a spin-glass transition above 2 

K [1]. However, the intrinsic ground state has remained unsolved, because previous 

samples contained many impurity spins caused by the low crystallinity. Recently, we 

succeeded in improving the sample quality by optimizing preparation parameters under 

hydrothermal conditions. The magnetic susceptibility of the new sample increases 

steeply below 15 K, followed by a sharp peak at 9 K that is indicative of long-range 

antiferromagnetic order. CdCu 3(OH) 6Br 2 has an isotropic kagome lattice made of Cu 2+ 

ions. The compound is an antiferromagnet with a Weiss temperature of -48 K and 

shows long-range antiferromagnetic order at 7 K. Thus, both the compounds show 

long-range order at rather high temperatures, which may be due to significantly large 

interlayer magnetic interactions. 

[1] Y. Okamoto et al., J. Phys. Soc. Jpn. 78, 033701 (2009). 

QE09 

Spin dynamics of triangular spin tubes 

Hirotaka Manaka 1 * and Yoko Miura 2 

1 Graduate School of Science and Engineering, Kagoshima University, Japan 

2 Suzuka National College of Technology, Japan 

Triangular spin tubes belong to a new category of one-dimensional Heisenberg 

antiferromagnets along the tubes coexisting with geometrically frustrated spin systems 

in the triangular plane. Recently, we discovered that chromium fluoride CsCrF 4 forms 

ideal equilateral triangular spin tubes with S=3/2[1]. All Cr ions are at equivalent sites, 

and each angle of Cr-Cr-Cr in the triangular plane is 60 deg.[2] Because superexchange 

interactions through the three Cr-F-Cr paths in each equilateral triangle may be kept 

in equilibrium at 0 K, we propose resonating spin-singlet pairs in each equilateral 

triangle. From DC magnetic susceptibility and adiabatic heat capacity data above 1.5 K, 

we concluded that there is no magnetic phase transition. Therefore, CsCrF 4 consists of 

a gapless spin-liquid ground state encompassing resonating spin-singlet pairs not only 

in each equilateral triangle but also along the tubes[2]. To clarify spin dynamics of the 

spin-liquid ground state, we performed linear and nonlinear AC magnetic susceptibility 

measurements on CsCrF 4. As a result, temperature dependence of a linear susceptibility 

exhibits a positive peak at around 4 K, while a nonlinear susceptibility exhibits a broad 

and negative peak at around 3.5 K. We found that a spin-glass like state was realized 

below 4 K. 

[1] H. Manaka et al., J. Phys. Soc. Jpn. 78, 093701 (2009). [2] H. Manaka et al., J. Phys. Soc. Jpn. 

80, 084714 (2011).

QE10 

Origin of field induced magnetic ordering in frustrated honeycomb 

lattice antiferromagnet 

Susumu Okubo 1 *, Tomonari Ueda 2 , Wei-min Zhang 3 , Takahiro Sakurai 4 , Masashi Fujisawa 1 , Hitoshi 

Ohta 1 , Nozomi Ohnishi 5 , Masaki Azuma 6 , Yuichi Shimakawa 5 and Nobuhiro Kumada 7 



3 Center for Collaborative Research and Technology Development, Kobe University, Japan 


5 Institute for Chemical Research, Kyoto University, Japan 


7 Graduate School of Medicine and Engineering, University of Yamanashi, Japan 

The ground state of honeycomb lattice antiferromagnet (HLAF) have been considered theoretically 

to be the Neel state similar to the square lattice antiferromagnet because both antiferromagnets 

are bipartite lattices. However, the honeycomb lattice has smaller coordination number 3 than 

the square lattice of 4 and it is close to the one dimensional chain. Therefore, the stronger spin 

fluctuation is expected in the HLAF. Actually, anomalous spin dynamics are reported in S=1/2 

HLAF InCu 3/2V 1/3O 3 [1]. On the other hand, the spin liquid state is expected in S=3/2 HLAF 

Bi 3Mn 4O 12(NO 3) due to no long range order down to 0.4K despite of the large Weiss temperature. 

Although no spin gap has been observed in the magnetic susceptibility of Bi 3Mn 4O 12(NO 3), 

it shows the field-induced magnetic ordering (FIMO) above around 6 T. Neutron diffraction 

measurements confirmed FIMO state and suggested that Dzyaloshinski-Moriya (DM) interaction 

plays an important role in the FIMO state. In order to estimate the DM interaction, high-field ESR 

measurements have been performed. The D-term of DM interaction is estimated to be 1.3K from 

the analysis of observed antiferromagnetic resonance mode. Origin of FIMO will be discussed in 

connection with the DM interaction and the other magnetic anisotropy. 

[1] S. Okubo et al, J. Phys. Soc. Jpn. 80 (2011) 023705 

QE11 

Semi-classical spin-liquid state as a low-energy excited state in 

frustrated quantum spin systems on triangle-based lattice system 

Makoto Isoda 1 , Hiroki Nakano 2 and Tôru Sakai 3 

1 Kagawa University, Japan 


3 JAEA SPring-8, Japan 

The magnetic and the thermal properties of the spin-1/2 Heisenberg antiferromagnets on the trianglebased 

lattice are summarized , focusing on the realization of the semi-classical spin-liquid state of 

the resonating doublet trimers formed on triangles, through the calculations for various systems 

such as the triangular , the kagome, the triangulated-kagome1), the Sierpinski-gasket like2) and the 

spatially anisotropic triangular lattices, which interpolates the triangular and the kagome lattices. 

The calculations have been performed by the numerical diagonalization method. On these systems, 

the peculiar behaviors have been found in the Heisenberg3,4) and the Ising5) models for spin- 

1/2 on those triangle-based lattices with nearest neighbor (nn) antiferromagnetic interaction. The 

peculiarities are the bending of the magnetic susceptibility as a function of temperature, the more than 

two peaks structure on the specific heat and the 1/3 magnetization plateau under magnetic field. Each 

of these peculiarities appears at the characteristic temperature or magnetic field corresponding to the 

magnitude of nn interaction, suggesting the predominance of the doublet trimer low energy excited 

state. The peculiarities reveal as an intrinsic character of the systems with the nn antiferromagnetic 

interaction depending on whether the lattice is formed by the equilateral triangle as a unit cell or not. 

1) M.Gonzalez et al., Mol. Cry. Liq. Cry. 233 (1993) 317. 2) T. Stosic et al., Phys. Rev. E 49 (1994) 1009. 3) M.Isoda, 

H.Nakano and T.Sakai, Mod. Phys. Lett. B 25 (2011) 909. 4) M.Isoda, H.Nakano and T.Sakai, J. Phys. Soc. Jpn. 80 (2011) 

084704. 5) M.Isoda, J. Phys.: Condens. Matter 20 (2008) 315202. 

QE12 

High pressure and low-temperature 31P NMR study of the twodimensional 

frustrated square lattice compound BaCdVO(PO4) 2 

Yuji Furukawa 1 , Beas Roy 1 , Ramesh Nath 2 , David C Johnston 1 , Yasuhiro Komaki 3 , 

Hideto Fukazawa 3 and Yoh Kohori 3 

1 

Department of Physics and Astronomy, Iowa State University / Ames Laboratory, 

USA 

2 

Indian Institute of Science Education and Research, India 

3 

Department of Physics, Chiba University, Japan 

We report first NMR study under pressures on BaCdVO(PO 4) 2, a S = 1/2 frustrated 

square-lattice (FSL) compound with a nearest neighbor exchange coupling J1 ~ - 3.36 

K and a next-nearest neighbor exchange coupling J2 ~ 3.53 K bearing J2/ J1 ~ 1.05. 

Based on the J2/J1 ratio, the system is known to be located close to the disordered 

ground state (known as 'nematic state') regime of the phase diagram. We have 

carried out 31P-NMR measurements under high pressure (up to ~ 2 GPa) and at low 

temperatures (down to ~0.1 K) using a dilution refrigerator to investigate the pressure 

effects on the magnetic properties of the system from microscopic point of view. Under 

ambient pressure, we observed a sharp peak in 31P spin lattice relaxation rate (1/T1) 

at TN ~ 1.05 K at H = 2.67 T, which corresponds to the antiferromagnetic ordering 

temperature. With increasing pressure, the peak position of 1/T1 shifts to lower 

temperature. This indicates that TN decreases with the application of pressure. We will 

discuss pressure effects on magnetic state based on the temperature dependence of the 

NMR spectra and of the 1/T1 under different magnetic fields and pressures. 

QE13 

QE14 

QE15 

Strong geometrical frustration in Fe oxychalcogenide 

Sungdae Ji 1 , K. Horigane 2 and K. Yamada 3 

1 CROSS, Japan 

2 University of Virginia, USA 

3 Tohoku University, Japan 


Kasteleyn transitions in the spin ice Dy2Ti2O7 Hiroaki Kadowaki 1 *, Naohiro Doi 1 , Hiroshi Takatsu 1 , Ryuji Higasginaka 1 , Yuji Muro 2 , Kiyoichiro 

Motoya 3 , Rei Morinaga 4 , Taku J Sato 4 , Takashi Tayama 5 , Toshiro Sakakibara 4 , Kazuyuki Matsuhira 6 

and Zenji Hiroi 4 

1 


2 

Toyama Prefectural University, Japan 

3 

Department of Physics, Tokyo University of Science, Japan 

4 

Institute for Solid State Physics, University of Tokyo, Japan 

5 

Department of Physics, University of Toyama, Japan 

6 

Department of Electronics, Kyushu Institute of Technology, Japan 

The spin ice model in the pyrochlore lattice, e.g. Dy 2Ti 2O 7, consisting of corner sharing tetrahedra 

has attracted much attention because of its intriguing frustration mechanism. The ground states of this 

system are macroscopically degenerate with the finite zero-temperature entropy, and the spins freeze 

in this manifold at low temperatures. The macroscopic degeneracy of the ground states is partly lifted 

under magnetic fields, where degrees of the degeneracy depend on direction and strength of the field. 

Interesting theoretical predictions, which have not been seriously investigated to date by experiments, 

are Kasteleyn transitions [1] in three and two space dimensions, which may occur under magnetic 

fields along a [100] direction [2] and fields tilted slightly from a [111] direction [3]. These transitions 

are classified into topological phase transitions which are characterized by line (string) defects. We 

have investigated these possibilities in the spin ice compound Dy 2Ti 2O 7 using magnetization and 

specific heat measurements. 

[1] P. W. Kasteleyn, J. Math. Phys. 4, 287 (1963). [2] L. D. C. Jaubert et al. Phys. Rev. Lett. 100, 

067207 (2008). [3] R. Moessner, S. L. Sondhi, Phys. Rev. B 68, 064411 (2003). 

Novel frustrated quantum antiferromagnets in the solid-solution 

Cs 2CuCl 4-xBr x through site-selective halide substitution 

Bernd Wolf*, Pham Thanh Cong, Natalia Kruger, Franz Ritter, Wolf Assmus and 

Michael Lang 

Physics Institute, Goethe-University Frankfurt (M), SFB/TR 49, D-60438 Frankfurt 

(M), Germany, Germany 

We report on the magnetic properties of tetragonal and orthorhombic single crystals of the solid 

solution Cs 2CuCl 4-xBr x (0 ≤ x ≤ 4). Two phase regions, namely an A-type orthorhombic and a 

B-type tetragonal structure, were detected in this system depending on the growing conditions. 

The two known orthorhombic end-member compounds Cs 2CuCl 4 and Cs 2CuBr 4 are classified 

as quasi-two-dimensional quantum antiferromagnets with different degrees of magnetic 

frustration. By measurements of the magnetic susceptibility χ(T) on orthorhombic single 

crystals with different Br concentrations, we found that the in-plane and out-of-plane magnetic 

correlations, probed by the position and height of a maximum in χ(T), respectively, do not show 

a smooth variation with x. Instead three distinct concentration regimes can be identified, which 

are separated by critical concentrations xc1 = 1 and xc2 = 2. This unusual magnetic behaviour 

can be explained by considering the structural peculiarities of the materials, which support a 

site-selective replacement of Cl- by Br- ions [1]. Consequently, the critical concentrations xc1 

(xc2) mark particularly interesting systems, where one (two) halide-sublattice positions are fully 

occupied. The magnetic properties of the tetragonal phase of Cs 2CuCl 4-xBr x differ strongly from 

those of the orthorhombic variants, reflecting changes in the Cu-coordination. 

[1] P. T. Cong et al., PRB 83, 064425, (2011) 

After Fe-based superconductors have emerged, it has generated a lot of controversies 

regarding to low ordered moments in parent compounds which have been explained 

by itinerant magnetism with Fermi surface nesting vs. magnetic frustration and/ 

or fluctuation effects in a large-local-moment system [1]. Very recently, Feoxychalcogenide 

has drawn attention, because it has been identified as a layered 

insulating antiferromagnet with the geometrically frustrated, so-called, “double 

diagonal stripe” spin structure which is realized only in Iron telluride among the 

family of Fe-based superconductors [2,3]. Here, we report elastic and inelastic neutron 

scattering study on La 2O 2Fe 2OSe 2. Our elastic neutron measurement at 5 K shows that 

magnetic Bragg peaks are diffusive and a obtained magnetic moment is 2.2 μ_B, which 

is smaller than a localized spin, S=5/2. Inelastic neutron scattering measurement shows 

that a strong magnetic fluctuation survives even at 300 K far above magnetic transition 

temperature, T_N = 90 K. Moreover, observed dispersive excitation reveals that the 

3rd nearest neighbor interaction is the key to explain a magnetic ground state on the 

geometrically frustrated lattice. 

[1]. David C. Johnston, Adv. in Phys. 59, 803 (2010). [2]. Jian-Xin Zhu et al., Phys. Rev. Lett. 104, 

216405 (2010). [3]. David G. Free and John S. O. Evans, Phys. Rev. B 81, 214433 (2010). 


Poster Tuesday



QE16 

Magnetic properties of the frustrated magnet Cu5(PO4) 3(OH) 4 on a 

peculiar spin network composed of pentagons and triangles 

Hikomitsu Kikuchi 1 , Nguyen Thi Tinh Y 1 , Yutaka Fujii 2 , Masashi Fujisawa 3 , Akira 

Matsuo 4 and Koichi Kindo 4 

1 

Department of Applied Physics, University of Fukui, Japan 

2 

Research Center for Development of Far-Infrared Region, University of Fukui, 

Japan 

3 

Research Center for Low Temperature Physics, Tokyo Tech, Japan 

4 

ISSP, The University of Tokyo, Japan 

Orthorombic Cu 5(PO 4) 2(OH) 4 (pseudomalachite) is a layered compound. Each Cu-O 

layer in this compound is well separated by PO 4 tetrahedrons. Spin network in bcplane 

of pseudomlachite is composed of triangles and pentagons, which will induce the 

spin frustration effect. This network can be a new type of geometrically frustrated spin 

lattice. Magnetic susceptibility, specific heat, high field magnetization are measured to 

study magnetic properties of Cu 5(PO 4) 2(OH) 4 using natural mineral samples. Magnetic 

ordering is observed at around 4.2 K. Spin entropy change at the transition temperature 

is about one fifth times smaller than that expected for a usual long range order. 1/5 

magnetization plateau is observed in the high field magnetization curve. The plateau 

can be explained based on the simple model in which the spin network is assumed to 

be composed of chain, dimer and monomer units. 

QE17 

Single crystal growth and magnetic properties of novel kagome 

compound KMn3Ge2O9 

Shigeo Hara* and Hirohiko Sato 

Department of Physics, Chuo-univ, Japan 

We have succeeded in synthesizing single crystals of a novel manganese oxide 

KMn 3Ge 2O 9 by a hydrothermal method. This compound has a hexagonal unit cell 

with lattice constants a = 11.77 Å and c = 13.77 Å. In this structure, edge-shared 

MnO 6 octahedra form layers separated by GeO 4 tetrahedra. In each layer, Mn ions 

with S = 2 spin form a rippled kagome lattice. Therefore, we can expect a frustrated 

magnetism. We measured temperature dependence of the magnetic susceptibility on a 

single crystal. The result suggests the existence of a strong magnetic frustration. The 

Curie constant and Weiss temperature are estimated at 3.4 emu K/mol Mn and - 84 

K, respectively. The negative Weiss temperature indicates that the nearest-neighbor 

exchange interaction among Mn ions is antiferromagnetic. At low temperatures, the 

susceptibility suggests the existence of multiple magnetic phases. For example, the 

susceptibility shows an antiferromagnetic like transition at 40 K and a spin-glass like 

transition at 20 K under 0.5 T of magnetic field perpendicular to the kagome lattice. 

The successive transitions are also observed in other conditions of magnetic field. We 

consider that these behaviors are driven from the strong magnetic frustration of the 

kagome lattice. 

QE18 

Specific heat study of geometrically frustrated magnet botallackite 

Cu 2(OH) 3Cl 

Hiroki Morodomi 1 , Yuji Inagaki 1 , Tatsuya Kawae 1 , Masato Hagihala 2 and X.g. Zhen 3 

1 Department of Applied Quantum Physics, Kyushu University, Japan 

2 Department of Physics, Saga University, Japan 

3 Department of Physics, Saga University, Japan 

Specific heat measurements have been performed in the geometrically frustrated 

magnets botallackite, Cu 2(OH) 3Cl with the triangular structure of the Cu 2+ ions. This 

is a different polymorphic form of clinoatacamite with the corner-sharing tetrahedral 

structure, which exhibits the coexistence of spin fluctuation and long range ordering 

below 6.2 K[1]. The specific heat of botallackite shows a sharp peak at TN=7.0K and 

approximately exhibits T3-dependence with lowering temperature in zero magnetic 

field. When a magnetic field is applied, TN shifts to lower temperatures and the peaks 

disappears at H=8 T. Moreover, no residual entropy is observed at lower temperatures. 

[1] X.G. Zheng, et. al., Phys. Rev. Lett. 95 057201 (2005). 


QE19 

Order and excitations in the frustrated quantum spin ladder BiCu 2PO 6 

P. Merchant 1 , S. Wang 2 , O. Zaharko 3 , Ch. Niedermayer 3 , L. P. Regnault 4 , M. Boehm 4 , 

M. Kenzelmann 2 and Ch. Ruegg 3 

1 London Centre for Nanotechnology, University College London, United Kingdom 

2 Laboratory for Developments and Methods, Paul Scherrer Institute, Switzerland 

3 Laboratory for Neutron Scattering, Paul Scherrer Institute, Switzerland 

4 Institut Laue-Langevin, France 

Quantum spin ladders are exceptional model systems showing non-trivial phenomena 

ranging from complex spin correlations in the ground state to rich phase diagrams with 

several quantum critical points. A fully quantitative understanding of their magnetic 

and thermodynamic properties may be achieved e.g. by powerful computational 

methods (DMRG, ED, bond operators) [1, 2] and comparison with high-precision 

experimental data, which may only be possible in such model systems [3]. BiCu 2PO 6 

is a new prototypical model material in which the spin ladders are frustrated by nextnearest 

neighbour exchange along the ladder legs, furthermore it can be doped with 

non-magnetic Zn 2+ impurities. The results of comprehensive neutron scattering studies 

on single crystals are presented of the elementary excitations and spin Hamiltonian of 

this frustrated ladder compound, as well as of the Zn-induced magnetic order and phase 

diagrams. The physics in this system is dominated by incommensurate correlations on 

all energy scales. 

[1] P. Bouillot et al., Phys. Rev. B 83, 054407 (2011). [2] B. Normand and Ch. Ruegg, Phys. Rev. B 

83, 054415 (2011). [3] e.g. see B. Thielemann et al., Phys. Rev. Lett. 102, 107204 (2009). 

QE20 

Melting of the spin ice state in Dy 2(Ti 1-xZr x) 2O 7 without dilution of rareearth 

ion 

Yuta Kodama, Kousuke Tsuruta, Daisuke Akahoshi and Toshiaki Saito* 

Department of Physics, Faculty of Science, Toho University, Funabashi City, Chiba 

274-8510, Japan 

The pyrochlore Dy 2Ti 2O 7 is a spin ice material, in which the spins reside on the lattice of 

corner-sharing tetrahedra with single-ion anisotropy along each local axis. The effective 

ferromagnetic interaction between spins leads to a highly degenerate ground state. Earlier 

researches [1][2] reported that the magnetic relaxation shows three successive processes; 

thermally activated Arrhenius process above 13 K, quantum tunneling process between 4 K 

~ 13 K, and process with strong spin correlation below 4 K. The relaxation in the medium 

temperature regime is the Davidson-Cole type [3] characterized by a wide distribution 

of relaxation time τ with a cut-off τ. The dilution of Dy causes disappearance of the ac 

susceptibility 15 K peak [1] due to a speeding up of relaxation [2]. In this talk, we examined the 

magnetic relaxation of Dy 2(Ti 1-xZr x) 2O 7 through ac magnetic susceptibility measurements in 

order to study B-site disorder effect. We found, for x above about 0.01, disappearance of the 15 

K peak, small frequency dependence, and substantial change of the magnetic relaxation from 

the Davidson-Cole type into the Cole-Cole one having no cut-off τ, indicating a major effect of 

B-site disorder on the spin ice state toward melting without dilution of Dy ion. 

[1] J. Snyder et al., Phys. Rev. B 70 (2004) 184431. [2] G. Ehlers et al., J. Phys. Condens. Matter 15 

(2003) L9. [3] K. Matsuhira et al., J. Phys. Condens. Matter 13 (2001) L737. [4] L.D.Jaubert and 

P.C.Holdsworth, J. Phys. Condens. Matter 23 (2011) 164222. 

QE21 

Unusual magnetic ordering of kagome lattice magnet 

[Cu3(CO3) 2(bpe) 3]•2ClO4 Hikomitsu Kikuchi 1 , Hayato Nakata 1 , Yutaka Fujii 2 and Toshifumi Taniguchi 3 

1 


2 


Japan 

3 


Cu 2+ ions in a hexagonal compound [Cu 3(CO 3) 2(bpe) 3]• 2ClO 4 (space group; P-6) 

form slightly distorted kagome lattice in its c-plane. Former study1) reported that the 

magnetic susceptibility increased rapidly below about 7 K indicating an occurrence 

of the ferromagnetic transition. Surprisingly, however, no anomaly in the specific heat 

was observed at the transition temperature in this compound. In order to scrutinize 

the magnetic properties, we measure the specific heat of this compound using single 

crystals under an applied magnetic field up to 7 T. 1H-NMR measurement is also 

carried out. NMR spectra-broadening and a divergent behavior of the spin-lattice 

relaxation rate are observed at around 7 K. Slight anomaly in the specific heat is 

observed and the anomaly temperature is found to depend on the magnetic field. These 

results suggest that entropy change associated with the magnetic ordering of this 

compound is vanishingly small. 

1) P. Kanoo et al. Dalton Trans. 2009, 5062.

QE22 

Field-induced staggered moments in the spin-gapped antiferromagnet 

on a deformed kagome lattice, Rb 2Cu 3SnF 12 

Hiroshi Tashiro 1 *, Masahide Nishiyama 1 , Akira Oyamada 1 , Tetsuaki Itou 1 , Satoru 

Maegawa 1 , Midori Yano 2 , Toshio Ono 3 and Hidekazu Tanaka 2 

1 Graduate School of Human and Environmental Studies, Kyoto University, Japan 


3 Department of Physical Science, Osaka Prefecture University, Japan 

Rb 2Cu 3SnF 12 is a kagome lattice antiferromagnet in which Cu 2+ ions with spin 1/2 interact with four 

exchange interactions, J1~200K>J2>J3>J4~100K. The ground state of this compound is a valence bond 

solid owing to the quantum and frustration effects, so that no magnetic ordering occurs [1,2]. We have 

performed 19F-NMR experiments on a single crystal of Rb 2Cu 3SnF 12 in order to clarify the microscopic 

property of the ground state. One sharp 19F-NMR spectrum at high temperature splits to several peaks at 

low temperatures due to different magnetic sites of 19F. The shifts of these peaks increase steeply below 

around 70K, whereas the static susceptibility decreases exponentially below this temperature owing to 

the singlet ground state with the spin-gap. The shifts are proportional to the applied field. These results 

strongly suggest that the local fields are produced by the staggered moments induced by the external field 

through Dzyaloshinsky-Moriya interaction. The staggered moments become dominant below 70K, while 

the parallel moments are remarkably small because of the large exchange interaction. This characteristic 

temperature differs from the spin-gap of 20K obtained from the susceptibility, because the large density of 

state in the dispersion curve around 70K contributes to the generation of the staggered moments [3]. 

[1] K. Morita, M. Yano, T. Ono, H. Tanaka, K. Fujii, H. Uekusa, Y. Narumi, and K. Kindo, J. Phys. Soc. Jpn. 77, 043707 (2008). [2] 

K. Matan, T. Ono, Y. Fukumoto, T. J. Sato, J. Yamaura, M. Yano, K. Morita, and H. Tanaka, Nature Phys. 6, 865-869 (2010). [3] H. 

Tashiro, M. Nishiyama, A. Oyamada, T. Itou, S. Maegawa, M. Yano, T. Ono, and H. Tanaka, J. Phys.: Conf. Ser. 320, 012052 (2011). 

QE23 

Magnetic order in finite size domains of the honeycomb lattice 

compound InCu2/3V1/3O3 E. Vavilova 1 *, M. Yakovleva 1 , M. Yehia 2 , R. Klingeler 3 , V. Kataev 2 , T. Taetz 4 , U. Loew 5 , A. Moeller 6 

and B. Buechner 2 

1 

Zavoisky Physical Technical Institute, RAS, Kazan, Russia 

2 

IFW Dresden, Dresden, Germany 

3 

Heidelberg University, Heidelberg,, Germany 

4 

Institut fur Anorganische Chemie, Universitaat zu Koln, Germany 

5 

Technische Universitaat Dortmund, Germany 

6 

University of Houston, Department of Chemistry and Texas Center for Superconductivity, USA 

The results of high field electron spin resonance, nuclear magnetic resonance, nuclear 

quadrupole resonance and magnetization studies addressing the ground state of the 

quasi two-dimensional spin-1/2 honeycomb lattice compound InCu 2/3V 1/3O 3 are 

reported. Uncorrelated finite size structural domains occurring in the honeycomb planes 

are expected to inhibit long range magnetic order. Surprisingly, magnetic resonance 

data show the development of two collinear antiferromagnetic (AFM) sublattices below 

35K and the presence of the staggered internal field. Magnetization data evidence a 

spin reorientation transition at 5.7T. Quantum Monte-Carlo calculations show that 

switching on the coupling between the honeycomb spin planes in a finite size cluster 

yields a Neel-like AFM spin structure with a substantial staggered magnetization at 

finite temperatures. ESR, NMR and NQR data allow to retrace the development of 

staggered magnetization during the crossover to ordered ground state. 

A. Yehia, et al., Phys. Rev. B 81, 060414 (2010) 

QE24 

Z_2 vortices in frustrated background of cuprates 

Maciej Fidrysiak and Paweł Rusek* 

Wroclaw University of Technology, Poland 

La 2-xSr xCuO 4 (LSCO) in the underdoped regime (x=0.02 - 0.05) is a non-collinear 

quantum antiferromagnet. The relevant order parameter is a triad of orthonormal 

vectors. The topology of the order parameter space allows the existence of Z_2 

vortices. Randomly distributed Sr dopants introduce holes into the Cu-O planes which 

are the source of fluctuating dipolar fields resulting in frustrated spin background. We 

study Z_2 vortices in the system in the framework of non-linear sigma-model coupled 

to SO(3) gauge fields which represent fluctuating frustrated background. In this model 

we describe explicitly not only spin degrees of freedom, but also the distribution of 

frustrations as opposed to pure spin systems. We have found explicitly a finite energy 

Z_2 vortex solution. Frustrations are concentrated in the soft core of Z_2 vortices and 

exponentially decrease at large distances. The chirality of spin system changes its sign 

in the vortex core as expected. Our vortex seems to be more relevant to the study of 

frustrated Heisenberg spin systems and the charge transport by vortices in cuprates than 

Z_2 vortices in pure spin degrees of freedom. 

QE25 

First-principles study of S=1/2 Kagome antiferromagnet 

Chung-yuan Ren* 

National Kaohsiung Normal University, Taiwan 

QE26 

Exotic phases in the frustrated hexagonal lattice 

Daniel C. Cabra* 

Physics Department, National University of La Plata, Argentina 

QE27 


3-D systems with interacting spins usually develop static long-range order when they 

are cooled. However, quantum fluctuations are enhanced in low dimensionality system 

with low spin value and lead to suppress the long-range ordering, and can show some 

extremely subtle, complex, and sometimes even useful magnetic behavior in solids. 

Here, using first-principles calculations, we investigated the atomic structural and 

magnetic properties of S=1/2 Kagome antiferromagnet A xCu 4-x(OH) 6Cl 2 (A=Zn, alkali 

metal ion). Cu ions are indeed found to locate at the tetragonally elongated intralayer 

site and Zn ions favorably rest on the higher symmetry interlayer site, in support of 

experimental contention. The intra- and inter-layer exchange interactions are studied 

in details. The effect of Dzyaloshinskii-Moriya interaction on the magnetic structure is 

also discussed. 

[1] M. P. Shores, E. A. Nytko, B. M. Bartlett, and D. G. Nocera, J. Am. Chem. Soc 127, 13462, (2005) 

[2] S. Chu, T.M McQueen, R. Chisnell, D.E. Freedman, P. Muller, Y.S. Lee, and D.G. Nocera, J. Am. 

Chem. Soc. (2010). 

We study the phase diagram of the Heisenberg model on the Honeycomb lattice with 

antiferromagnetic interactions up to third neighbors along the line J2=J3, close to the 

point where it has macroscopic degeneracy at the classical level. Using the Schwinger 

boson technique followed by a mean field decoupling and exact diagonalization 

for small systems we find an intermediate phase with a spin gap and short range 

Neel correlations even in the strong quantum limit 1/2. We have also studied the 

magnetization curve for J3=0, close to J2/J1 = 1/2 where the classical ground state is 

also highly degenerate. The properties of the magnetization curve and phase transitions 

are studied by means of Montecarlo, which shows many interesting transitions. 

Light scattering in spin liquid systems 

Dirk Wulferding 1 *, Peter Lemmens 1 , Vladimir Gnezdilov 2 , Tianheng Han 3 , Young S. 

Lee 3 , Hiroyuki Yoshida 4 , Yoshihiko Okamoto 5 and Olga Volkova 6 

1 IPKM, TU-BS, Braunschweig, Germany 

2 ILTPE NAS, Ukraine 

3 MIT, Massachusetts, USA 

4 NIMS, Tsukuba, Japan 

5 ISSP, Tokyo, Japan 

6 MSU, Moscow, Russia 

When quantum spin systems are restricted in dimensionality and coordination they 

realize spin liquid states with enhanced quantum fluctuations and exotic correlation 

functions. We compare the experimentally determined excitation spectra of different 

spin liquid candidates such as the s=1/2 Heisenberg antiferromagnet on a kagome 

lattice and weakly coupled spin chain system in Herbertsmithite and (NO)Cu(NO 3) 3 

using Raman scattering. This technique is sensitive to fractional spinon excitations. The 

effect of the crystal’s lattice structure and defects on the spin dynamics is investigated. 

The data is also compared with recent theoretical modelling. Work supported by DFG, 

B-IGSM and NTH School for Contacts in Nanosystems. 

D. Wulferding, et al., Phys. Rev. B 82, 144412 (2010) V. Gnezdilov, et al., arXiv:1203.2818 (2012) D. 

Wulferding, et al., arXiv :1111.2167 (2012) 


Poster Tuesday


QF01 


Molecular nanomagnets as quantum simulators 

Paolo Santini 

University of Parma. Italy 

Quantum simulators (QSs) are controllable quantum systems that can be used to 

simulate other quantum systems. QSs can tackle problems intractable on classical 

computers. Here we focus on the dynamics of qubits encoded in chains of molecular 

nanomagnets. For istance, we have shown that Cr 7Ni rings are good candidates qubits 

and can be linked to each other either directly or through magnetic complexes [1,2]. 

We theoretically show that the dynamics of such chains can be controlled by means of 

uniform magnetic pulsed fields and used to mimic the coherent time evolution of other 

quantum systems (e.g., spin-one chains) [3]. We propose two significant proof-ofprinciple 

experiments [3]. 

[1] G.A. Timco et al., Nature Nanotechnology 4, 173 (2009) [2] A. Candini et al., Phys. Rev. Lett. 

104, 037203 (2010) [3] P. Santini, S. Carretta, F. Troiani, G. Amoretti, Phys. Rev. Lett. 107, 230502 

(2011) 

QF02 

ESR signature of the next-nearest-neighbor interactions in the S = 1/2 

chain compound (6MAP)CuCl3. M. Ozerov 1 , A. A. Zvyagin 2 , E. Cizmar 3 , F. Xiao 4 , C. P. Landee 4 , J. Wosnitza 1 and S. A. 

Zvyagin 1 

1 

Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 

Dresden, Germany 

2 

Institut fur Festkorperphysik, Technische Universitat Dresden, Dresden, Germany 

3 

Centre of Low Temperature Physics, P.J. Safarik University, Kosice, Slovak 

4 

Department of Physics and Carlson School of Chemistry, Clark University, 

Worcester, Massachusetts, USA 

Electron spin resonance (ESR) studies of the S = 1/2 chain material (6MAP)CuCl 3 

[6MAP = C 6H 9N 2] are presented. Two modes with asymmetric with respect to a 

simple gapless Zeeman splitting resonance positions have been observed in the 

low-temperature ESR spectrum. This shows that the simple S = 1/2 Heisenberg 

antiferromagnet chain model, employed so far, is not sufficient for a complete 

description. The frequency-field diagram of magnetic excitations is interpreted in 

the frame of the recently developed theory for S = 1/2 chains with nearest- and nextnearest-neighbor 

interactions [A.A. Zvyagin, Phys. Rev. B 79, 064422 (2009)]. A good 

qualitative agreement with experiment has been achieved. The work was supported in 

part by DFG and EuroMagNET II (EU Contract No. 228043). 

QF03 

Electron spin resonance in the spin-ladder compound BPCB 

S. Zvyagin 1 , E. Cizmar 2 , M. Ozerov 1 and J. Wosnitza 1 

1 

Dresden High Magnetic Field Laboratory (HLD) Helmholtz-Zentrum Dresden- 

Rossendorf, Dresden, Germany 

2 

Centre of Low Temperature Physics, P.J. Safarik University, Kosice, Slovak 

Magnetic excitations in the spin-ladder material (C5 2H 12N 2)CuBr 4 (known as BPCB) 

are probed by means of electron spin resonance (ESR) spectroscopy in magnetic 

fields up to 16 T. The gap between the ground state and the first excited state, 16.5 

K (or 1.42 meV), is detected directly. In addition, our experiments provide clear 

evidence for a pronounced anisotropy (~ 5% of the dominant exchange interaction), 

responsible for a shift of the observed ESR line and a specific angular dependence of 

resonance absorptions. The results are explained in frame of the recently developed 

theory for ESR in spin-ladders (Furuya et al., arXiv: 1107.5965). The work was done 

in collaboration with B. Thielemann, K. W. Kramer, Ch. Ruegg, O. Piovesana, M. 

Klanjsek, M. Horvatic, and C. Berthier. The work was supported in part by DFG and 

EuroMagNET II (EU Contract No. 228043). 


QF04 

Non-magnetic impurity effect of S=1/2 spin ladder system (pipdH) 2Cu1 xZnxBr4 Chiori Yokoyama 1 , Weimin Zhang 2 , Takahiro Sakurai 3 , Susumu Okubo 4 *, Hitoshi Ohta 5 , Eiichi 

Matsuoka 6 , Hitoshi Sugawara 7 and Hikomitsu Kikuchi 8 

1 

Kobe University, Japan 

2 

Center for Collaborative Research and Technology Development, Kobe University, Japan 

3 

Center for Supports to Research and Education Activities, Kobe University, Japan 

4 

Molecular Photoscience Research Center, Kobe University, Japan 

5 

Molecular Photoscience Research, Kobe University, Japan 

6 

1Graduate School of Science, Kobe University, Japan 

7 

Graduate School of Science, Kobe University, Japan 

8 


Low dimensional spin system shows fruitful magnetic properties such as the Bose-Einstein condensation 

of magnon or the spin liquid state. Non-magnetic impurity effect in a quantum spin chain, which arises 

as an appearance of magnetic moment with spin correlation at around the impurity, is one of typical 

quantum effects of correlated spins. (pipdH) 2CuBr 4 is known as a model substance of weakly coupled 

spin 1/2 Heisenberg antiferromagnetic ladder system. Recently, we succeeded in synthesizing Zn-doped 

(pipdH) 2Cu 1-xZn 1-xBr 4 single crystal. Samples were confirmed to be in a single phase and have the same 

crystal structure as the pure system (pipdH) 2CuBr 4 by X-ray diffraction measurements. To check magnetic 

properties, the magnetic susceptibility and the magnetization measurements are performed by the SQUID 

magnetometer. The magnetic susceptibility shows a maximum related to the spin ladder and the Curie 

increase at low temperature related to the doping of Zn. The Curie term increases as the Zn concentration 

increase. Observed non-magnetic impurity effect of S=1/2 spin ladder system will be discussed in 

connection with AKLT model. 

QF05 

High-field multi-frequency ESR in the S=2 Heisenberg 

antiferromagnetic chain compound MnCl3(bpy) Masayuki Hagiwara 1 *, Shojiro Kimura 2 , Yuichi Idutsu 1 and Zentaro Honda 3 

1 


2 


3 


QF06 

MOVED 

High field magnetization of bimetallic chain with alternating ising and 

Heisenberg spins 

Yibo Han 1 , Jozef Strecka 2 , Takanori Kida 1 , Zentaro Honda 3 , Masami Ikeda 1 and Masayuki 

Hagiwara 1 * 

1 

KYOKUGEN, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan 

2 

Department of Physics, Faculty of Science, P. J. Safarik University, Park Angelinum 9,040 01 

Kosice, Slovakia, Slovak 

3 

Department of Functional Materials Science, Graduate School of Science and Engineering, 

Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan 

3d-4f bimetallic chain [Dy(NO3)(DMSO)2Cu(opba)(DMSO)2] built from alternating 

dysprosium(3+) and copper(2+) ions has been synthesized and magnetically studied. 

Magnetic susceptibility as well as high-field magnetization of the polycrystalline sample 

was measured under the temperature down to 1.3 K and the magnetic field up to 52 T. After 

performing correction for the temperature independent paramagnetism, the magnetization 

curve recorded at 1.3 K shows a rapid increase with the magnetic field in the low-field 

range 0-3 T, followed up with a less steep increase in the field range 5-34 T before tending 

towards its saturation value at 34 T. The observed magnetization process can be interpreted 

in terms of the spin-1/2 chain model with alternating Ising and Heisenberg spins, which 

accounts for both parallel and perpendicular Zeeman's energy of Dy and Cu ions. The good 

fitting of the experimental data by using the above theoretical model suggest the effective 

antiferromagnetic exchange constant J/kB= -26 K, the highly anisotropic g-factor of Dy 

ions and almost isotropic g-factor of Cu ions. It was concluded that a new type of onedimensional 

Ising-Heisenberg spin chain was found.

QF07 

Thermal conductivity and magnetic susceptibility of the 4-leg spinladder 

system (La 1-xY x) 2Cu 2O 5 and the 5-leg spin-ladder system (La 1- 

XEu x) 8Cu 7O 19 

Takayuki Kawamata*, Takashi Noji and Yoji Koike 


We have measured the thermal conductivity and magnetic susceptibility of the 4-leg spin-ladder 

system (La 1-xY x) 2Cu 2O 5 (x = 0.01) and the 5-leg spin-ladder system (La 1-xEu x) 8Cu 7O 19 (x = 0, 

0.01). It has been found that the temperature dependence of the thermal conductivity along 

the spin-ladders of (La 0.99Y 0.01) 2Cu 2O 5, La 8Cu 7O 19 and (La 0.99Eu 0.01) 8Cu 7O 19 shows only one 

peak originating from the thermal conductivity due to phonons at ~15K. That is, the thermal 

conductivity due to spins, κspin, has not been observed in these compounds, though κspin 

was expected to be large owing to the exchange interaction along the spin-ladders as large as 

~1000K. Since the antiferromagnetic transition temperature, TN, is as large as 137K and 103K 

in La 2Cu 2O 5 [1] and La 8Cu 7O 19 [2], respectively, it has been concluded that the comparatively 

large exchange interaction between spin-ladders disturbs the thermal conduction due to 

spins along the spin-ladders. Moreover, it has been found that the temperature dependence 

of the magnetic susceptibility below TN is clearly different between (La 0.99Y 0.01) 2Cu 2O 5 and 

(La 0.99Eu 0.01) 8Cu 7O 19, which may be related to the difference of the ground state between the 

odd- and even-leg spin-ladder systems. 

[1] K. Kudo et al., J. Phys. Soc. Jpn. 72 (2003) 2551. [2] I. A. Zobkalo et al., Physica B 234-236 

(1997) 734. 

QF08 

Magnetic susceptibility of the quasi one-dimensional spin system 

Sr 2V 3O 9 

Takayuki Kawamata*, Masanori Uesaka, Mitsuhide Sato and Yoji Koike 


According to the magnetic susceptibility of polycrystalline samples of the quasi onedimensional 

spin system Sr 2V 3O 9, this compound undergoes a weak ferromagnetic 

transition due to the Dzyaloshinsky-Moriya (DM) interaction at TN ~ 5K [1]. We have 

grown single crystals of Sr 2V 3O 9 [2] and measured the magnetic susceptibility along 

the [101] direction, χ[101], along the [10-1] direction, χ[10-1], and along the b-axis, 

χb. It has been found that temperature dependences of χ[101], χ[10-1] and χb show 

Bonner-Fisher-type behavior and that the anisotropy is very small at high temperatures 

above TN, indicating that Sr 2V 3O 9 is regarded as an isotropic one-dimensional 

Heisenberg spin system. At low temperatures below TN, however, both χ[10-1] and 

χb increase with decreasing temperature, while χ[101] decreases. This anisotropic 

behavior is consistent with the canted spin state proposed from the ESR measurements 

[3]. 

[1] E. E. Kaul et al., Phys. Rev. B 67 (2003) 174417. [2] M. Uesaka et al., J. Phys.: Conf. Ser. 200 

(2010) 022068. [3] V. A. Ivanshin et al., Phys. Rev. B 68 (2003) 064404. 

QF09 

Magnetic property of a single crystal of spin-1/2 triple-chain magnet 

Cu3(OH) 4SO4 Yutaka Fujii 1 *, Yuya Ishikawa 2 , Hikomitsu Kikuchi 2 , Yasuo Narumi 3 , Hiroyuki 

Nojiri 3 , Shigeo Hara 4 and Hirohiko Sato 4 

1 


Japan 

2 


3 


4 

Department of Physics, Chuo University, Japan 

A spin-1/2 triple-chain magnet Cu 3(OH) 4SO 4 (antlerite) is a candidate 'idle-spin' system in 

which magnetic moments on central spin chain seem to disappear, while the rest exhibit 

a long-range order below TN=5.5 K [1]. Our previous proton NMR study with a powder 

sample almost supported this scenario, although it was difficult to determine the spin 

structure [2]. Recently, successive phase transitions and anisotropy of phase diagram were 

found from the results of magnetization measurements with high-quality single crystals 

of Cu 3(OH) 4SO 4 [3]. In order to study phase transitions in the present compound in detail, 

we have performed specific heat measurements under magnetic fields up to 7 T and in the 

temperature range down to 2 K and proton NMR experiments at several frequencies with 

single crystals. We found at least three successive phase transitions at zero field around 

TN. Complicated phase diagrams involving changes of spin structures were suggested. 

[1] S. Vilminot et al., J. Solid State Chem., 170, (2003) 255. [2] Y. Fujii et al., J. Phys.: Conf. Ser., 

145, (2009) 012061. [3] S. Hara et al., J. Phys. Soc. Jpn., 80, (2011) 043701. 

QF10 

QF11 

QF12 

Thermal conductivity of anisotropic spin ladder 

Hamed Rezania* 

razi university, Iran 


Thermal conductivity due to magnons in high-quality single crystals of 

the two-leg spin ladder system (Ca,Sr,La) 14Cu 24O 41 

Koki Naruse 1 *, Takayuki Kawamata 1 , Mitsuhide Sato 1 , Masumi Ohno 1 , Kazutaka Kudo 2 , Norio 

Kobayashi 3 and Yoji Koike 1 

1 Department of Applied Physics, Tohoku University, Japan 



In order to enhance the thermal conductivity due to magnons, κmagnon, in the two-leg spin 

ladder system (Ca,Sr,La) 14Cu 24O 41, we have grown single crystals using high-purity raw materials, 

improved the quality of the single crystals by annealing in O2 and measured the thermal 

conductivity along the spin ladders. In both Ca 9La 5Cu 24O 41 and Sr 9La 5Cu 24O 41, the thermal 

conductivity shows a very large peak around 150K owing to the contribution of κmagnon along 

the spin ladders[1,2]. However, no enhancement of κmagnon has been observed in spite of the 

increase of the purity of the raw materials and the O2-annealing. In Sr 14Cu 24O 41, on the other hand, 

a large enhancement of κmagnon has been observed through the O2-annealing. These results 

indicate that the mean free path of magnons, lmagnon, has already limited by the disorder of the 

atomic arrangement due to the substitution of Ca and La for Sr in Ca 9La 5Cu 24O 41 and Sr 9La 5Cu 24O 41, 

while lmagnon is enhanced owing to the decrease of spin defects through the O2-annealing in nonsubstituted 

Sr 14Cu 24O 41. Accoringly, it is necessary for the enhancement of κmagnon to remove the 

disorder of the atomic arrangement in the spin ladders in (Ca,Sr,La) 14Cu 24O 41. 

[1] K. Kudo, S. Ishikawa, T. Noji, T. adachi, Y. Koike, K. Maki, S. Tsuji, and K. Kumagai: J. Phys. 

Soc. Jpn. 70, 437 (2001). [2] C. Hess C. Baumann, U. Ammerahl, B. Buchner, F. Heidrich-Meisner, W. 

Brenig, and A. Revcolevschi: Phys. Rev. B 64, 184305 (2001). 

Magnetic property of Ni 2+ antiferromagnetic perfect triangle cluster 

Emika Takata 1,2 *, Minoru Sanda 1 , Katsutaka Kubo 2 , Takayuki Asano 2 , Akira Matsuo 1 , 

Koichi Kindo 1 and Masaki Oshikawa 1 



The magnetic properties of spin systems with frustration have attracted much attention 

for a long time. The fundamental structure causing the frustration is “triangle”. The 

magnetic properties of the antiferromagnetic perfect triangular cluster (APTC) with 

half-integer spins have been already studied well. [1] By contrast, there are little 

experimental data on the APTC with integer spins. Such an APTC is expected to 

possess a non-magnetic, singlet ground state. Recently, Liu et al. have investigated 

magnetic properties of S=1 APTC, [Ni 3(μ 1,3-N 3) 3(2,2'-bpy) 3](ClO 4) 3•3H 2O. It is 

believed as one of model materials for the S=1 APTC. [2] We synthesized it and 

measured the magnetization process (M(H)) and the temperature dependence of the 

magnetic susceptibility (χ(T)) of the material. We calculated M(H) and χ(T) in the 

simple ISOTROPIC S=1 APTC. However, the experimental results clearly cannot 

be accounted for by the calculated results. When the spin is greater than or equal to 

1, generally a single ion anisotropy D can present. Thus we consider an anisotropic 

model Hamiltonian by including D. We will discuss the experimental data based on 

calculations using the new Hamiltonian with D. 

[1] for example T. Yosida et al., J. Phys. Soc. Jpn. 57 (1988) 1428. [2]J.L. Liu et al., Aust. J. Chem. 

63 (2010) 1111. 

We have studied the thermal conductivity of anisotropic spin ladder model with 

antiferromagnetic coupling constants between spins on the both rung and ladder 

directions. Kubo formalism has been applied to study temperature dependency of 

thermal conductivity of this model hamilltonian. The bond operator formalism is 

used to transform the spin model to a hard core bosonic gas. We have used the green's 

function approach to obtain the temperature dependence of spin excitation spectrum. 

We have found the temperature dependence of the thermal conductivity for various 

exchange coupling constants and anisotropies in both coupling strengths. We have 

obtained the increase of coupling constant along ladder direction leads to decrease 

of thermal conductivity. Furthermore the effect of local anisotropy anisotropy on the 

thermal conductivity has more significant in comparison with other one. 

1)E. Dagootto and T. M. Rice, Science 271, 618 (1996) 2)A. Klumper and D. C. Johnston, Phys. 

Rev. Lett, 84, 4701 (2000) 3)A. V. Sologubenko and K. Gianno, H. R. Ott, U. Ammerahl and A. 

Revolevschi, Phys. Rev. Lett, 84, 2714(2000) 4)X. Zotos, F. Naef, P. Prelovse, Phys. Rev. B, 55, 

11029 (1997) 5)K. Louis, P. Prelovse and X. Zotos, Phys . Rev. B 74, 235118(2006) 


Poster Tuesday


QF13 


The magnetic properties of the newly synthesized trinuclear copper 

complex 

A. N. Ponomaryov 1 *, K. Y. Choi 1 , N. Kim 2 , S. Yoon 2 , B. J. Suh 3 and Z. H. Jang 4 

1 Department of Physics, Chung-Ang University, Seoul, Korea 

2 Department of Chemistry, Kookmin University, Seoul, Korea 

3 Department of Physics, The Catholic University of Korea, Bucheon, Korea 

4 Department of Physics, Kookmin University, Seoul, Korea 

We present magnetic properties of a newly synthesized single molecule magnet (SMM) 

Cu 3(μ 3-OMe)(μ-OMe)(μ-O 2CAr 4F-Ph ) 2(O 2CAr 4F-Ph) 2(HOMe) 3. In this compound, three 

copper ions with s=1/2, connected by one μ 3-bridged methoxide, form a spin triangle, 

whereby two Cu 2+ ions are 5 coordinated and the other Cu 2+ ion is 4 coordinated. By 

means of SQUID magnetometer, temperature dependence of magnetic susceptibility 

χ(T) was measured in the range from 2 K to 300 K at the external field of 100 Oe 

and field dependence of magnetization M(H) was measured at 2 K and 300 K in the 

range from 0 to 7 T. From an analysis of the magnetization data of the polycrystalline 

powder sample using ITO (Irreducible Tensor Operator) method, we obtain the 

antiferromagnetic exchange coupling constants of J 1 = -143.65 K, J 2 = -143.78 K, J 3 = 

-143.61 K and the g-factor of g = 2.66. A further analysis with a model Hamiltonian 

including anisotropic exchange interactions is on-going. 

QF14 

Magnetization process of S=1/2 diamond chain compound 

Na 2Cu 3Ge 4O 12 

Minoru Sanda 1 *, Keisuke Matsuura 1 , Takayuki Asano 1 , Junfeng Wang 2 , Akira Matsuo 2 , Koichi 

Kindo 2 , Hiroki Morodomi 3 , Yuji Inagaki 3 and Tatsuya Kawae 3 



3 Department of Applied Physics, Kyushu University, Japan 

Frustrated magnetism is one of the most fascinating systems because these systems have a great variety of 

quantum phenomena, and a lot of research activities are going on. Diamond chain in which spins exist on 

the Diamond-shaped lattice is one of examples of 1D-frustrated magnet. In this system, it is theoretically 

expected that not only the frustration but also low-dimensionality induces the quantum phenomena. 

Experimentally, Cu 3(CO 3)(OH) 2 was reported as an S=1/2 Diamond chain compound, and its magnetic 

properties are studied actively [1]. Recently, Mo et al. reported the crystal structure of Na 2Cu 3Ge 4O 12, 

which has magnetic ions Cu 2+ (3d9:S=1/2) arranging in Diamond chain [2]. This compound has a shortrange 

order at T(SLO)~10K and a long-range order at T(N)=2K by means of magnetic susceptibility and 

heat capacity measurements [2][3]. We performed high field magnetization measurement using pulse 

magnetic field up to 55T at T(N)

QF19 

Spectral signatures of magnetic Bloch oscillations in 1D ferromagnets 

Sergey Shinkevich and Olav F. Syljuasen 

Department of Physics, University of Oslo, Norway 

Domain walls in a one-dimensional gapped easy-axis ferromagnet can exhibit Bloch 

oscillations in an applied magnetic field. We investigate how exchange couplings 

modify this behavior within an approximation based on non-interacting domainwall 

bound states. In particular we obtain analytical results for the spectrum and the 

dynamic structure factor, and show where in momentum space to expect equidistant 

energy levels, the Wannier-Zeeman ladder, which is the spectral signature of magnetic 

Bloch oscillations. We compare our results to previous calculations employing a single 

domain-wall-approximation, and make predictions relevant for the material cobalt 

chloride dihydrate (CoCl 2•2H 2O). 

1) Jordan Kyriakidis and Daniel Loss, Phys. Rev. B 58, 5568 (1998). 2) W. Montfrooij, G. E. 

Granroth, D. G. Mandrus, and S. E. Nagler, Phys. Rev. B 64, 134426 (2001). 3) N.B. Christensen, K. 

Lefmann, I. Johannsen, and O. Jørgensen, Physica B 276, 784 (2000). 

QF20 

Quasi-one-dimensional magnetic phase as a competing ground state in 

a frustrated magnet 

Krunoslav Prsa 1 , Mark Laver 2 , Martin Mansson 1 , Ivica Zivkovic 3 , Peter Derlet 4 , Sebastian Guerrero 4 , 

Christopher Mudry 4 , Oksana Zaharko 2 , Sang-wook Cheong 5 , Hee-taek Yi 5 , Jorge Gavilano 2 , Joachim 

Kohlbrecher 2 , Michel Kenzelmann 6 and Joel Mesot 2 

1 

Laboratory for Solid State Physics, ETH Zurich, Switzerland 

2 

Laboratory for Neutron Scattering, Paul Scherrer Institute, Switzerland 

3 

Institute of Physics, Croatia 

4 

Condensed Matter Theory, Paul Scherrer Institute, Switzerland 

5 

Department of Physics and Astronomy, Rutgers University, USA 

6 

Laboratory for Developments and Methods, Paul Scherrer Institute, Switzerland 

Low-dimensional physics is interesting because it is driven by fluctuations and it may result in exotic 

phenomena, like the fractionalization of quantum numbers and spinons in magnetic chains. In magnetic 

systems, the reduction of dimensionality occurs due to anisotropic short-ranged interactions. Generally, 

transition metal oxides order at low temperatures. Here, in geometrically frustrated Ca 3Co 2O 6, we 

show that by geometric frustration a stable quasi--one--dimensional (Q1D) magnetic phase emerges 

from a competition of degenerate ground states. This phase coexists and competes with the 3D 

antiferromagnetism in a large range below the 3D ordering temperature. We show that (i) constituent 

entities of this Q1D phase are shaped as rods in real space with alternating up and down magnetized 

sections (d=15A, l=320A at 15 K) along the chain axis where (ii) the sections belong to a degenerate 

ferrimagnetic class of ground states, (iii) these magnetic rods are arranged randomly in the frustrated 

triangular plane, (iv) they occupy a significant volume fraction (estimated 25% of moments at 15K) and 

(v) they are correlated with the magnetic response of this material. These results provide a new general 

possibility of a frustration--stabilized one--dimensional phase in physics. 

QF21 

Crossover of magnetic relaxation from 2D-spin ice like state to ordered 

state in layered single molecular magnet networks 

Yuta Kodama 1 , Rikako Ishii 2 , Chihiro Kachi-terajima 2 , Hitoshi Miyasaka 3 , Daisuke 

Akahoshi 1 and Toshiaki Saito 1 * 

1 Dept. of Phys., Fac. of Sci., Toho Univ., Funabashi , Chiba 274-8510, Japan 

2 Dept. of Chem., Fac. of Sci., Toho Univ., Funabashi , Chiba 274-8510, Japan 

3 Dept.of Chem., Div. of Mat. Sci., Grad. Sch. of Nat. Sci. and Tech., Kanazawa Univ., 

Ishikawa 920-1192, Japan 

Layered 2D single molecular magnet (SMM) network [Mn(saltmen)]4[M(CN) 6]ClO 4•nH 2O (M=Mn, 

Fe[1]) is a strongly frustrated system. The each SMM unit [Mn(saltmen) ] (ST =4) is ferromagnetically 

connected through the [M(CN)6] unit (S=1 for Mn, and S=1/2 for Fe) within a layer. The origin of 

the frustration [2] is a competition between the orthogonally oriented two uniaxial axes of the SMM 

unit and the ferromagnetic interaction, leading to a macroscopically degenerated ground state as the 

pyroclore 3D-spin ice. Our previous work [2] for M=Mn showed no transition down to 2 K through 

the Weiss temperature Θ= 8.3 K and Davidson-Cole (DC) type magnetic relaxation as 3D-spin ice 

[3]. However, for M=Fe, a distinct anomaly of relaxation time is observed at 2.6 K (Θ = 7.5 K), and 

the relaxation is the Cole-Cole (CC) type, suggesting a magnetic order. In this work, we measured 

ac susceptibility of M = Mn1-xFex (x = 0 ~ 1.0). We found that the relaxation is not the DC type for 

x=0.1, and changes into CC type for x > 0.3 accompanying the distinct anomaly of relaxation time. The 

results suggest that 2D-spin ice-like state is ordered into a randomly frozen state above x ~ 0.1. 

[1] H. Miyasaka et al., J. Am. Chem. Soc. 118 (1996) 981. [2] T. Saito et al. (2012), in preparation 

(partly presented in ICM 2009). [3] K. Matsuhira et al., J. Phys. Condens. Matter 13 (2001) L737. 

QF22 

QF23 

QF24 


Magnetic properties of the novel low-dimensional spin-1/2 magnet α-Cu 2As 2O 7 

V. Kataev 1 *, Y. C. Arango 1 , E. Vavilova 2 , M. Abdel - Hafiez 1 , O. Janson 3 , A. Tsirlin 3 , H. Rosner 3 , S.-l. 

Drechsler 1 , M. Weil 4 , G. Nenert 5 , R. Klingeler 6 , O. Volkova 7 , A. Vasiliev 7 and B. Buechner 1 

1 Leibniz Institute for Solid State and Materials Research IFW Dresden, Germany 

2 Zavoisky Physical Technical Institute of the Russian Academy of Sciences, 420029, Kazan, Russia 

3 Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany 

4 Institute for Chemical Technologies and Analytics, Vienna University of Technology, A-1060 Vienna, Austria 

5 Institut Laue-Langevin, Boıte Postale 156, 38042 Grenoble Cedex 9, France 

6 Kirchhoff Institute for Physics, University of Heidelberg, D-69120 Heidelberg, Germany 

7 Low Temperature Physics Department, Moscow State University, Moscow 119991, Russia 

In copper pyroarsenate α-Cu 2As 2O 7, the quantum spins S = 1/2 localised at the Cu sites in the 

structurally well defined dimer chains interact predominantly in one spatial dimension (onedimensional 

spin systems). Magnetic properties of this new material have been thoroughly 

investigated by means of magnetization, heat capacity, electron spin resonance, and nuclear magnetic 

resonance techniques, as well as by density functional theory (DFT) calculations and quantum Monte 

Carlo (QMC) simulations. The data reveal that the magnetic Cu-O chains in the crystal structure 

represent a realization of a quasi-one-dimensional (1-D) coupled alternating spin-1/2 Heisenberg 

chain model with relevant pathways through nonmagnetic AsO4 tetrahedra. Owing to residual 3-D 

interactions, antiferromagnetic long range ordering at TN ~10 K takes place. The experimental data 

suggest that substantial quantum spin fluctuations take place at low magnetic fields in the ordered 

state. DFT calculations and QMC fits enable quantitative evaluation of the exchange couplings. We 

conclude that the electronic state of the central ion in the nonmagnetic AsO 4 side groups plays a 

crucial role for determining the relevant interchain pathways which makes α-Cu 2As 2O 7 distinct in its 

magnetic properties from other representatives of this class of compounds [1]. 

[1] Y.C. Arango, E. Vavilova, M. Abdel-Hafiez et al., Phys. Rev. B 84, 134430 (2011) 

Low temperature magnetic properties of the dilutable frustrated spinladder 

Bi(Cu1-xZnx) 2PO6 Shuang Wang 1 , Krunoslav Prsa 2 , Neda Nikseresht 2 , Christian Ruegg 3 , E. Pomjakushina 4 , Kazimierz 

Conder 4 and Henrik M Ronnow 2 

1 

Laboratory for Quantum Magnetism/Laboratory for Developments and Methods, Ecole Polytechnique 

Federale de Lausanne, 1015 Lausanne Paul Scherrer Institut, 5232 Villigen, Switzerland 

2 

Laboratory for Quantum Magnetism, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne, 

Switzerland 

3 

Laboratory for Neutron Scattering, Paul Scherrer Institut,5232 Villigen, Switzerland 

4 

Laboratory for Developments and Methods, Paul Scherrer Institut,5232 Villigen, Switzerland 

Quantum antiferromagnets with a spin-ladder magnetic network show an energy gap in the spin excitation 

spectrum and may possess an intrinsically disordered (spin liquid) ground state. BiCu 2PO 6 (BCPO) 

shows a structure where Cu 2+ magnetic ions (S=1/2) form two-leg zigzag ladders along the b-axis, which 

closely corresponds to theoretical quasi-1D AF spin ladder model. We can reveal quantum nature of low 

temperature behavior by studying the effect of non-magnetic impurities (e.g. Zn 2+ , Ni + ) introduced at 

magnetic Cu-sites. Recently, single crystals of Bi(Cu 1-xZn x) 2PO 6 (0≤x≤0.05) were successfully synthesized 

and studied by NMR for the first time [1,2]. We present here the specific heat Cp (H,T), ac susceptibility 

(f,T) and dc magnetization M(H,T) on single crystal sample of the undoped BCPO and 5% Zn-doped 

BCPO (Zn005BCPO) with field applied along main crystallographic axes focusing on low temperatures 

T < 10 K. We argue that the ground state of the Zn doped compound (Zn005BCPO) has features of both 

spin-glass and long range magnetic order, and that glassiness is lost under application of higher magnetic 

fields. We show the H-T magnetic phase diagram. 

[1] S.Wang., E. Pomjakushina, T. Shiroka, G. Deng, N. Nikseresht, Ch. Ruegg, H.M. Rønnow, and K. Conder. J.Crystal.Growth.313, 

51-55 (2010) [2 ]F. Casola, T. Shiroka, S. Wang, K. Conder, E. Pomjakushina, J. Mesot and H.-R. Ott, Phys. Rev. Lett. 105, 067203 

(2010) 

51V-NMR study of the quasi-one-dimensional antiferromagnet 

BaCo2V2O8 Yukiichi Ideta 1 , Yu Kawasaki 1 , Yutaka Kishimoto 1 , Takashi Ohno 1 , Yoshitaka 

Michihiro 1 , Zhangzhen He 2 , Yutaka Ueda 3 and Mitsuru Itoh 4 

1 

Institute of Technology and Science, The University of Tokushima, Japan 

2 

Fujian Institute of Research on the Structure of Matter, Chinese Academy of 


3 


4 

Materials and Structures Laboratory, Tokyo Institute of Technology, Japan 

The double rectangle-like powder pattern has been observed in the 51V-NMR 

spectrum for the quasi-one dimensional antiferromagnet BaCo 2V 2O 8 below TN = 5.4 

K. The powder pattern indicates the existence of two V sites with different internal 

field, 2.1 and 3.8 kOe, although V atoms occupy only one magnetically symmetric site 

where the scalar type transferred field from the surrounding Co 2+ magnetic moments is 

zero. The internal field at V site is explained by taking into account of the classical and 

the pseudo-dipolar fields from Co 2+ magnetic moments. In the paramagnetic state, the 

nuclear spin-lattice relaxation is dominated by the antiferromagnetic spin fluctuation 

via the dipolar field, which is proved by the linear relation between the nuclear spinlattice 

relaxation rate divided by temperature 1/T1T and the magnetic susceptibility. 

The change in the slope of 1/T1T against the magnetic susceptibility around 150 K 

suggests the change in the antiferromagnetic spin fluctuation spectrum. Below 60 K, 1/ 

T1 shows the thermal activation-type temperature dependence signaling the formation 

of spin gap. 


Poster Tuesday


QF25 


Magnetic properties of one-dimensional chain of O2 confined in 

nanospaces of MFI-zeolite 

Akihiro Hori 1 , Kanako Kuwana 2 , Tatsuo C Kobayashi 2 , Yasushi Wanikawa 3 , Yoshiki Kubota 3 , 

Kenichi Kato 1 , Masaki Takata 1 , Ryotaro Matsuda 4 and Susumu Kitagawa 1 

1 

RIKEN SPring-8 Center, Japan 

2 

Okayama University, Japan 

3 

Osaka Prefecture University, Japan 

4 

Exploratory Research for Advanced Technology (ERATO), Japan 

We have studied the molecular arrangement and the magnetic properties in O 2 adsorbed in nanoporous 

compounds [1-3]. We found that the O 2 adsorbed in MFI zeolite form a one-dimensional chain. The O 2 

adsorption isotherm shows a plateau and the step, indicating a phase transition. It is found by means of the 

x-ray diffraction measurements that the zeolite deforms from monoclinic to orthorhombic corresponding 

to the step of adsorption isotherm.In the low-adsorption case, the adsorbed O 2 aligns linearly in the straight 

and sinusoidal channels in MFI zeolite. In the high-field magnetization measurements, the magnetization 

process does not show the linear field dependence characteristic to one-dimensional Heisenberg 

antiferromagnet and presents the metamagnetic transition similar to the case of O 2-O 2 dimer reported 

previously [1, 2]. This result may suggest that the singlet ground state is realized at low fields and the fieldinduced 

orientational change of molecular axis occurs. In the high-adsorption case, the adsorbed O 2 seems 

to align in rows of two. The temperature dependence of susceptibility shows the first-order transition with 

large hysteresis. By XRD measurement, the structural phase transition from orthorhombic to monoclinic 

with decreasing temperature was found, which is not observed in N 2 adsorbed compound. 

[1] T. C. Kobayashi et al., Prog. Theor. Phys. Suppl. 159 (2005) 271. [2] A. Hori et al., J. Phys. 200 (2010) 0022018. [3] 

A. Hori et al., J. Low. Temp. Phys. 159 (2010) 122. 

QF26 

Quantum spin transport in a Heisenberg spin chain 

Nan-hong Kuo 1 , Sujit Sarkar 2 and Chong Der Hu 1 * 

1 Physics, NationalTaiwan University, Taiwan 

2 PoornaPrajna Institute of Scientific Research, India 

QG01 

WITHDRAWN 

Magnetic transition of plastic deformed Si-doped Ni 3Mn alloy 

Kowan-young Ko 1 *, Sung-won Ko 2 and John Graham Booth 3 

1 Faculty of mechanical engineering, Ulsan College University, Korea 

2 Department of biological science, Sungkyunkwan University, Korea 

3 School of computing, science and engineering, Salford University, United Kingdom 

Structural and magnetic properties of plastic deformed Si-doped Ni 3Mn alloy were 

studied and compared with those of undeformed specimen investigated by powder 

neutron diffraction and diffuse purely magnetic scattering measurements in which 

coexistences of ferromagnetic and antiferromagnetic interactions were still existing 

even far above Neel temperature. Two specimens showed spin glass properties and 

disordered face-centered cubic structure but lattice parameters were a little different 

value of 3.5961 Å and 3.5890 Å. Magnetic properties showed very different Neel 

temperatures of 87.5 K and 62.5 K respectively. The paramagnetic Curie temperature 

appeared by -325 K and 125 K and therefore effective magnetic moments were 

calculated by 3.51 μB and 0.41 μB respectively. The reasons for different magnetic 

transition could be introduced by the elongation of ferromagnetic clusters and change 

of atomic environments effect after plastic deformation. This report shows two kinds of 

magnetic properties by plastic deformation. 


QG02 

Incommensurate-commensurate phase transition in TbNi 5 induced by 

external magnetic field. 

Elena Sherstobitova 1 *, Alexander Pirogov 1 , Vadim Sikolenko 2 , Savva Bogdanov 1 and 

Roland Schedler 3 

1 Institute of Metal Physics of UD of RAS, Russia 

2 Joint Institute for Nuclear Research, Dubna, Russia 

3 Hahn-Meitner Institute, Berlin, Germany 

The rare earth intermetallic RNi 5 compounds are attractive subjects for the study of 

the exchange and crystal field interactions due to their simple crystal and magnetic 

structures. The magnetic ordering in TbNi 5 compound has been interpreted in terms 

of FAN-like incommensurate structure at temperatures between 23 K and 10 K. On 

cooling sample down to T = 10 K order-order type magnetic phase transition from the 

incommensurate phase to a “lock-in' phase takes place. In the present work we report 

the results of neutron diffraction experiment on TbNi 5 single crystal sample in external 

magnetic field up to μ0H = 1T. Abrupt change of the intensity of (001) Bragg peak and 

satellites (001)± occurs within temperature interval 7 K -10 K due to magnetic phase 

transition from the incommensurate phase to a “lock-in' phase. It has been found that 

the application of external magnetic field up to μ0H = 0.1T at the temperature T = 11K 

along [100]-axis of TbNi 5 single crystal recovers zero-field low temperature 'lockin' 

magnetic structure. The external magnetic field increase up to μ0H = 0.4T leads to 

transformation of the modulated magnetic structure to a ferromagnetic structure. 

QG03 

First-principles dynamical CPA study of ferro- and antiferromagnetism 

of transition metals 

Yoshiro Kakehashi* and Sumal Chandra 

Department of Physics, University of the Ryukyus, Japan 

Quantitative explanation of the finite-temperature properties of 3d transition metals and 

alloys has been a long standing problem in metallic magnetism because their Coulomb 

interactions are comparable to the band widths and simple perturbation approach is 

not applicable to such systems. We present here the first-principles dynamical CPA 

combined with the LDA+U Hamiltonian toward quantitative calculations of magnetic 

properties at finite temperatures and explain quantitatively or semi-quantitatively the 

finite-temperature magnetism of 3d transition metals from V to Ni. We obtained the 

Curie-Weiss spin susceptibility with meff=1.8 muB (Expt. 2.1 muB) in V, the Pauli 

paramagnetic susceptibility in Cr being in agreement with the experimental data, as 

well as the Curie-Weiss susceptibilities in Fe, Co, and Ni whose meff quantitatively 

agree with the experimental data (3.2, 3.2, and 1.6 muB). Calculated ground-state 

magnetizations are 2.58, 1.72, and 0.64 muB for Fe, Co, and Ni, being in good 

agreement with the experimental data (2.2, 1.74, and 0.62 muB). On the other hand we 

obtained the Curie temperatures 1900K, 2100K, and 620K for Fe, Co, and Ni which 

are somewhat overestimated because of the single-site approximation. We also clarify 

the systematic change of the single-particle DOS in these systems. 

QG04 

High-coercive metastable ferromagnetic state induced in the Ising 

antiferromagnet Fe 0.5TiS 2 

Nikolay Baranov 1 *, Elizaveta Sherokalova 2 , Alexey Volegov 2 , Alexey Proshkin 3 , 

Nadezshda Selezneva 2 , Andrey Gubkin 4 and Ekaterina Proskurina 2 

1 Micromagnetic laboratory, Institute of Metal Physics, Russia 

2 Institute of Natural Sciences, Ural Federal University, Russia 

3 Laboratory of ferromagnetic alloys, Institute of Metal Physics, Russia 

4 Laboratoty of neutron studies of matter, Institute of Metal Physics, Russia 

The transition metal (T) dichalcogenides TX2 (X = S, Se, Te) with a layer crystal structure being 

intercalated with 3d-transition (M) metals demonstrate different magnetic states depending on the 

type and concentration of M-atoms as well as on the parent TX2 matrix [1]. In the present work, the 

magnetic susceptibility, magnetization, electrical resistivity, magnetoresistance and powder neutron 

diffraction measurements have been performed for the Fe intercalated compound Fe 0.5TiS 2. It has been 

shown that this compound exhibits an antiferromagnetic (AF) ground state below the Neel temperature 

TN = 140 K. Application of the magnetic field at T < TN induces a metamagnetic phase transition to 

the ferromagnetic (F) state, which is accompanied by the large magnetoresistance effect (~ -27 %). 

The field-induced AF-F transition is found to be irreversible below 100 K. At low temperatures, the 

magnetization reversal in the metastable F state is accompanied by substantial hysteresis (up to 100 

kOe) which is associated with the Ising character of Fe ions. This work was supported by the RFBR 

(project 12-02-00778) and by the program of the Ural Branch of RAS (project № 12-T-1012). 

[1] Baranov N. V. et al. J. Phys. Condens. Matter. 17 (2005) 5255

QG05 

Magnetic and thermoelectric properties of the solid solutions Mn 1- 

XNi XS 

Sergey Aplesnin 1 , Oksana Romanova 1 , Ludmila Ryabinkina 1 , Olga Demidenko 2 , 

Anatoly Galyas 2 and Kazimir Yanushkevich 2 

1 L.V. Kirensky Institute of Physics, Russia 

2 Scientific-Practical Materials Research Centre NAS of Belarus, Belarus 

In connection with intensive development of a microelectronics and spintronics, interest 

of researchers to the magnetic semiconductor materials showing magnetoresistivity 

effect and metal-insulator transition has increased. New sulphide solid solutions 

Mn 1-XNi XS (0 TN. The effective magnetic moment are found to be μef. 

f=5,04 μВ for Х=0,05 and μeff.=5,16 μВ for Х=0,1. Change in the conductivity type 

from the hole to the electronic at Х=0,05 is revealed on the basis of measurements of 

thermoelectric power. 

QG06 

Field induced anisotropy in NiMn and NiMnPt alloys 

Yildirhan Oner 

Department of Physics, Istanbul Technical University, Dept. of Physics, 34469, 

Istanbul, Turkey 

We report the detailed characterization of the magnetic properties of polycrystalline 

disks of Ni 72Mn 28 and Ni 72-xMn 28Pt x (x=1.0, 4.0, and 10.0) at 4.2 K induced by field 

cooling (FC). It is found that the FC-induced anisotropy field ,HK and coercivity , HC 

are strongly enhanced by the addition of nonmagnetic Pt impurities. The remanent 

magnetization in the direction of the initial applied field (in the disk plane) for each 

samples can be rotated from 0° to 1800 and back to 0° in various stationary fields above 

and below HK and the parallel component of the rotated remanents are measured. 

From the analysis of the angular dependence of ML, we show that these results can be 

accounted for by the coexistence of Mn(Ni)-rich and /or Mn(Ni)-deficient nano scale 

regions coupled antiferromagnetically. It is found that the unidirectional anisotropy 

originates from interfacial exchange interactions between these regions. Up to some 

critical angle rotation (θC) relative to H, the unidirectional anisotropy field turns 

rigidly with the sample, while above θC, the coupled regions become unstable and 

magnetically rearrange such that a unidirectional anisotropy is induced along H . 

QG07 

X-ray-absorption near-edge structure and X-ray magnetic circular 

dichroism studies of a Lu 2Fe 16.5Ru 0.5 single crystal 

E. A. Tereshina 1 , A. Smekhova 2 , O. Isnard 3 , A. V. Andreev 4 and A. Rogalev 5 

1 Institute of Physics, Academy of Sciences, 18221 Prague, Czech Republic 

2 Faculty of Physics, Moscow State University, 119991 Moscow, Russia 

3 Universite Joseph Fourier/Institut Neel (CNRS), 38042 Grenoble Cedex, France 

4 Institute of Physics, Academy of Sciences, Czech Republic 

5 European Synchrotron Radiation Facility (ESRF), 38043 Grenoble Cedex, France 

The magnetism of R 2Fe 17 with the smallest rare-earth R=Lu (hexagonal Th 2Ni 17 structure type) is essentially 

associated with its Fe sublattice behavior. Strong contribution of the local antiferromagnetic (AF) Fe-Fe 

interactions in the overall ferromagnetic (F) exchange considerably lowers the ordering temperature (TN=274 

K) and balances the non-collinear antiferromagnetic phase above the Curie temperature TC=130 K. Generally, 

various doping elements (M) in Lu 2Fe 17- xM x suppress fully the AF states by strengthening the ferromagnetic ones 

accompanied by a dramatic TC increase. However, recently a unique case of antiferromagnetism stabilization in 

the whole range of magnetic ordering in Lu 2Fe 17- xRu 1x was reported [1], and this work is dealing with the local 

studies of intrinsic magnetic properties of Lu 2Fe 16.5Ru 0.5. A single-crystalline sample of Lu 2Fe 16.5Ru 0.5 has been 

investigated by X-ray-absorption (XANES) and X-ray magnetic circular dichroism (XMCD) techniques in the 

applied magnetic field up to ±3 T at 7 K. By probing the lutetium L2,3-, iron K- and ruthenium L2 absorption 

edges, information on magnetic states of the constituents of Lu 2Fe 16.5Ru 0.5 is obtained. Small but noticeable 

induced magnetic moments with an antiparallel orientation to Fe moments have been registered on Lu and Ru 

sites. 

[1] E.A. Tereshina et al., J. Appl. Phys. 105 (2009) Art. No. 07A747. 

QG08 

QG09 

QG10 

The magnetovolume effect of Y 2Fe 17-xGa x 

Daiki Haruna and Tatsuo Kamimori 

Ehime University, Japan 


Study of the metamagnetic behavior of Ni-Co-Mn-Sb alloy in high 


Rie Y Umetsu 1 *, Xiao Xu 2 , Wataru Ito 3 , Takumi Kihara 4 , Masashi Tokunaga 4 , Kohki 

Takahashi 1 and Ryosuke Kainuma 2 


2 Department of Materials Science, Graduate School of Engineering, Tohoku University, Japan 

3 Department of Materials and Environmental Engineering, Sendai National College of Technology, Japan 

4 <strong>International</strong> MegaGauss Science Laboratory, Institute for Solid State Physics, The University of Tokyo, 

Japan 

In order to investigate metamagnetic behavior and temperature dependence of equilibrium magnetic field 

of the martensitic transformation for Ni-Co-Mn-Sb, magnetization experiments up to 18 T static magnetic 

field and up to 40 T pulsed magnetic field were performed. Polycrystalline specimen of Ni 41Co 9Mn 39Sb 11 

was prepared by induction melting, and annealed at 1173 K for 1 day. Transformation temperatures, TM, and 

entropy change, ΔS, between the martensite phase and parent phase were examined with DSC. Magnetic 

measurements were performed with using a SQUID magentometer up to 5 T, by extracting method up 

to 18 T static magnetic fields, and also by induction method up to 40 T pulsed magnetic fields. In the 

thermomagnetization curves, it was observed that TM decreased with increasing the applying magnetic field, 

H, with a rate of dTM/dH = 3.8 K/T. An estimated value of ΔS from the Clausius-Clapeyron relation, is about 

15.8 J/K-kg, being in good agreement with the value obtained by the DSC. For the isothermal magnetization 

curves, metamagnetic behavior associated with the magnetic field induced martensitic reverse transformation 

was observed. Arresting behavior of the martensitic transformation was confirmed in lower temperature, as 

similar to the Ni(Co)-Mn-Z (Z = In, Sn, Ga) alloys. 

Magnetic Transition and Thermal Expansion in LaFe13-x-yCoySix Jianli Wang 1 , Stewart James Campbell 2 *, Shane J Kennedy 3 , Precious Shamba 4 , Rong 

Zeng 4 , Shixue Dou 4 and Guang Heng Wu 5 

1 

Institute for Superconducting & Electronic Materials, The university of Wollongong, Australia 

2 

School of PEMS, The University of New South Wales, Canberra, Australia 

3 

Bragg Institute, ANSTO, Australia 

4 

Institute for Superconductivity and Electronic Materials, The University of Wollongong, Australia 

5 

National Laboratory for Condensed Matter Physics, Institute of Physics,, Chinese Academy of 


Materials with a large magnetocaloric effect (MCE) continue to attract significant attention for cooling 

applications with particular interest in the isothermal entropy changes at first-order magnetic transitions [1]. 

The large entropy change in LaFe 13-xSi x is associated with negative lattice expansion and metamagnetic 

transition behaviour [2]. We have investigated LaFe 13-x-yCo ySi x to clarify the influence of magneto-structural 

coupling on the MCE. The Curie temperatures of LaFe 13-xSi x increase with Si content from TC=219 K for 

x=1.6 to TC=250 K for x=2.6 with further enhancement to TC=281 K on substitution of Co to LaFe 9.4CoSi 2.6. 

A pronounced positive spontaneous volume magnetostriction has been observed below TC and the anomalous 

thermal expansion attributed to the volume dependence of the magnetic energy. Our results show that the 

magnetic transition changes from first order for LaFe 11.4Si 1.6 to second order for LaFe 10.4Si 2.6 and LaFe 9.4CoSi 2.6. 

The different natures of the magnetic transitions in LaFe 13-x-yCo ySi x have been discussed in terms of the 

classical model for itinerant ferromagnets and the volume dependence of the magnetic energy. 

[1] KA Gschneidner, Jr., VK Pecharsky and AO Tsoko, Rep. Prog. Phys. 68, 1479 (2005) [2] FX Hu, 

BG Shen, JR Sun, ZH Cheng, GH Rao, X Zhang, Appl. Phys. Lett. 78, 3675 (2001) 

The unit cell volume and the Curie temperature of Y 2Fe 17 increases by substitution of 

Ga for Fe. This phenomenon is understood as a property of Invar materials, dTc/dV > 

0, because the compounds R 2Fe 17 have Invar properties. However, in the substitution 

of Si for Fe, dTc/dV is negative. Kamimori et. al. proposed damping of the Invar 

properties by these substitutions. In this work, the magnetovolume effect of Y 2Fe 17xGax 

was investigated by measuring temperature dependence of unit cell volume 

and forced volume magnetostriction. X-ray diffraction was used to measure unit cell 

volume at under R.T. and thermal expansion meter at above R.T.. The forced volume 

magnetostriction was measured by three terminals capacitacne method under magnetic 

field up to 1.5T. The forced volume magnetostriction at R.T. is positive. This shows 

Y 2Fe 17-xGa x compounds have Invar property. However, the magnitude of the forced 

volume magnetostriction decreases violently by the substitution of Ga for Fe. This 

tells us the substitution of Ga for Fe in R 2Fe 17 decreases magnetovolume effect and 

attenuates Invar characters of the compounds. 


Poster Tuesday



QG11 

Pressure effect on the electrical resistivity of La1.09(Fe0.845Si0.155) 13 

compound 

Makio Kurisu 1 *, D. T. K. Anh 2 and Go Nakamoto 3 

1 

Department of Physics, Ehime University, Japan 

2 

School of Materials Science, Japan Advanced Institute of Science and Technology, 

Japan 

3 

School of Materials Science, Japan Advansed Institute of Science and Technology, 

Japan 

QG12 

QG13 

WITHDRAWN 

One- and two-magnon and exciton raman scattering in 

antiferromagnetic CoF2: Experiment and theory 

Eric Meloche 1 , Michael Cottam 1 and David Lockwood 2 

1 Department of Physics and Astronomy, University of Western Ontario, Canada 

2 Institute for Microstructural Sciences, National Research Council, Canada 

Experimental data are reported for the temperature and polarization dependence of the 

one- and two-magnon Raman light scattering in the rutile-structure antiferromagnet 

CoF 2 (Neel temperature = 38 K). A detailed analysis of the one-magnon Stokes and 

anti-Stokes Raman spectra is presented resulting in comprehensive experimental data 

for the temperature variation of the one-magnon frequency, line width, and integrated 

intensity. A similar analysis was carried out for the two-magnon scattering. The lowlying 

excitons were also investigated at low temperatures and comparisons are made 

with results from earlier Raman, infrared, and neutron scattering work. The Green’s 

function equation of motion method was employed to derive the excitation energies 

and spectral intensities over a broad range of temperatures for the magnetic excitations 

in a spin S = 3/2 anisotropic antiferromagnet with strong spin-orbit coupling. Results 

were obtained using RPA for the product of operators at different sites while the singleion 

anisotropy terms were treated exactly by generating a closed set of coupled Green’s 

function equations. The numerical results are in good agreement with one-magnon 

Raman light scattering data. Results were deduced for some exchange and anisotropy 

parameters and the relative magnitudes of the magneto-optical coefficients in the 

interaction Hamiltonian. 

Thermodynamic and transport properties of Ru 2-xFe xCrSi (1.3 ≤ x ≤ 

1.8) 

Masakazu Ito*, Toru Hisamatsu, Tsugumi Rokkaku, Iduru Shigeta and Masahiko 

Hiroi 

Department of Physics and Astronomy, Graduate School of Science and Engineering, 

Kagoshima University, Japan 

Full-Heusler compounds with the generic chemical formula X 2YZ (X and Y are 

transition elements, Z is sp element) attract much interests because this system shows a 

number of physical properties and some of them have a potential for the technological 

applications. The ferromagnetic Heusler compound Ru2-xFexCrSi is one of candidate 

materials expected a half metallicity1] and this system has relatively high Curie 

temperature TC~500 K for x > 1.4 2]. We have carried out electric resistivity ρ(T) and 

specific heat Cp(T) measurement of Fe-rich Ru 2-xFe xCrSi ( x = 1.3, 1.6, and 1.8 ). For 

all samples, ρ(T) shows metallic behavior ( ∂ρ/∂T ) in 20 < T < 300 K, and upturn 

at around 20 K. In low-temperature range, Cp(T) can be described by Debye’s law. 

Although a coefficient of lattice specific heat β is insensitive for Fe concentration x, a 

electronic specific heat part γ decreases slightly with increasing x. For each x sample, 

we estimated total density of states (DOS) at the Fermi level D(EF) from γ. 

1]S. Mizutani et al., Mater. Trans. 47, 25 (2006). 2]M. Hiroi et al., Phys. Rev. B 79, 224423 (2009) 


QG14 

Magnetic structure and excitations of the one-dimensional quantum 

antiferromagnet RbCoCl3 Mattia Mena 1 *, Eva Hirtenlechner 2 , Nora Haenni 3 , Simon Ward 4 , Karl Kraemer 3 , 

Christian Ruegg 4 and Des Mcmorrow 1 

1 

London Center for Nanotechnology, UCL, United Kingdom 

2 

Institut Laue-Langevin, France 

3 

University of Bern, Switzerland 

4 

Paul Scherrer Institut PSI, Switzerland 

RbCoCl 3 is a hexagonal perovskite in which the Co 2+ ions have an effective spin S = 1/2 and form onedimensional 

(1D) chains perpendicular to the basal plane. Measurements of the magnetic susceptibility 

confirm its antiferromagnetic behaviour; the difference between the maximum of the susceptibility and the 

Neel temperature indicates 1D magnetic correlation. Isostructural materials, such as CsCoCl 3 and TlCoCl 3, are 

quasi-1D Ising-like spin systems[1][2]. The lowest-lying magnetic modes in their spectrum consist of pairs 

of domain-wall excitations and are described by a strongly anisotropic Heisenberg Hamiltonian[3]. Here we 

report the first results of a comprehensive neutron scattering study of the magnetic structure and excitations in 

RbCoCl 3. A neutron diffraction experiment on HRPT (SINQ,PSI,Switzerland) revealed the existence of two 

phase transitions at TN1=28K and TN2=14K. At TN1 there is a paramagnetic-to-antiferromagnetic transition, 

while at TN2 a low-temperature phase with a new propagation vector develops. Inelastic neutron scattering 

experiments were performed on LET (ISIS,RAL,UK) and IN22 (ILL,Grenoble,FR). Between TN1 and TN2, 

as well as above TN1, excitations characteristic for an Ising magnet are observed. Below TN2 an additional 

splitting of the modes is discovered. Results and analysis of the data from LET will be presented and discussed. 

[1] J. P. Goff, D. A. Tennant and S. E. Nagler, Phys.Rev. B 52, 15992 (1995). [2] A. Oosawa, Y. Nishiwaki, T. Kato 

and K. Kakurai, J. Phys. Soc. Jpn. 75, 15002 (2006). [3] N. Ishimura and H. Shiba, Progr. Theor. Phys. 63, 743 (1980). 

QG15 

Antiferromagnetic transition in Ru 2CrSi in magnetic fields 

Masahiko Hiroi 1 *, Kaori Uchida 1 , Iduru Shigeta 1 , Masakazu Ito 1 , Keiichi Koyama 1 , 

Shojiro Kimura 2 and Kazuo Watanabe 2 

1 Department of Physics and Astronomy, Kagoshima University, Japan 


Heusler compounds Ru 2-xFe xCrSi for Fe-rich region were recently found to be 

ferromagnetic and to be candidates for a half-metal, where conduction electrons are 

fully spin-polarized.[1] In the Heusler compound Ru 2CrSi, on the other hand, an 

antiferromagnetic (AF) transition at TN =14 K was revealed by specific heat and 

magnetization measurements.[2] In this study electrical resistivity is measured in 

magnetic fields up to 14.5 T and the AF transition in magnetic fields is investigated. In 

the temperature dependence of the resistivity at zero field a clear kink is observed at 

TN =14 K. With decreasing temperature the resistivity turns upward from the kink at 

TN. This kink can be regarded as an indication of the AF transition. With increasing 

magnetic field the resistivity only slightly changes and even at 14.5 T the clear kink is 

observed. From the kink TN is found to decrease just a little in high magnetic fields. 

TN at 14.5 T is lower than TN at zero field by 0.5 K. These results demonstrate that the 

AF state in Ru2CrSi is unusually unaffected by strong magnetic field. 

[1] M. Hiroi et al., Phys. Rev. B 76, 132401 (2007). [2] M. Hiroi et al., to be published in J. Phys.: 

Conf. Series. 

QG16 

Assessment of Curie temperature by magnetization vs. temperature 

(M-T) scans in a granular magnetic Cu-Fe-Ni alloy 

Sung Kang 1 , Atsuki Takano 2 , Dong-hae Lee 2 , Mahoto Takeda 2 *, Zenji Hiroi 3 and 

Masaki Takeguchi 4 

1 

Research Institute of Industrial Science & Technology (RIST), Korea 

2 

Yokohama National University, Japan 

3 

University of Tokyo, Japan 

4 

National Institute for Materials Science (NIMS), Japan 

The present study has investigated the Curie temperature of Cu-Fe-Ni ternary alloy which is known as a 

granular giant magneto-resistance (GMR) material with a high magneto-resistance (MR) ratio. At first, we 

surveyed the relationship between the microstructure and the aging temperature of precipitates formed in Cu- 

Fe-Ni alloys isothermally annealed at 873K and 1073K for various aging times, using a transmission electron 

microscopy (TEM). According to TEM observations, we have revealed that two or more nano-scale particles 

with a cubic shape and rod shape precipitates were formed at 873K and 1073K, respectively. The critical 

temperature of the drastic change of the microstructure coincides with the Curie temperature of magnetism 

of the alloy. And, the Curie temperature has been determined by the magnetization (M) vs. temperature (T) 

scans, using the SQUID magnetometer. The experimentally determined temperature of 1028K was as high as 

a bulk Fe-Ni alloy, even though nano-scale ferromagnetic particles are finely distributed in copper matrices. 

The high Curie temperature has, however, well explained the temporal evolutions in both microstructure and 

magnetic properties occurring during isothermal annealing. 

[1] S. Kang, M. Takeda, Z. Hiroi, G. W. Kim, C. G. Lee, and B. H. Koo, J. Phys. D: Appl. Phys. 43, 

415001 (2010) [2] S. Kang, M. Takeda, M. Takeguchi, and D. S. Bae, J. Alloy. Compds. 496, 196 (2010)

QG17 

Design strategy for strongly coupled diradicals: Systematic Approaches 

of intramolecular magnetic interactions 

Kyoung Chul Ko, Daeheum Cho and Jin Yong Lee* 

Department of Chemistry, SungKyunKwan University, Korea 

A new series of neutral radicals (DP1-DP6) based on diazaphenalenyl were designed 

via heteroatomic modifications. As spin sources, the designed radicals were 

implemented in four different diradical model systems (Model I, II, III, and IV) 

by changing the reference radical and the linkage, and their magnetic interactions 

between the designed radicals and the reference radical were investigated by using 

density functional theory calculations. The trend in strength of magnetic interactions 

of radicals was found to be identical in different model systems. In particular, as a new 

family of spin source radical, DP3 could be a potential candidate in designing new 

organic magnetic materials due to its strong magnetic coupling and high stability in 

diradical systems.(1) We divided 8 monoradicals into α-group and β-group according 

to Mulliken spin density values of the connected atoms. The overall trends in the 

strength of magnetic interactions of diradicals were found to be identical in three 

different model systems (Model I, II and V). NN-ethylene-PO was calculated to have 

the strongest magnetic coupling constant with ferromagnetism, and even stronger (more 

than twice) than NN-ethylene-NN which was reported to have strong antiferromagnetic 

interactions in a previous experiment. 

(1) Ko, K. C.; Son, S. U.; Lee, S.; Lee, J. Y. J. Phys. Chem. B 2011, 115, 8401. 

QG18 

Single crystal growth and physical properties of metalic 

antiferromagnet (Mn,Fe) 3Si 

So Nara 1 , Sun Chang Che 1 , Haruhiro Hiraka 2 , Kenji Ohoyama 2 , Yasuo Yamaguchi 2 , 

Hiroyuki Miki 3 and Kazuyoshi Yamada 4 

1 Dept. of Physics, Tohoku University, Japan 

2 IMR,Tohoku University, Japan 

3 IFS,Tohoku University, Japan 

4 WPI,Tohoku University, Japan 

Heusler alloys Mn 3-x Fe x Si(x=0~3) have a face centered cubic (DO3 type) structure in the whole 

x-region from the antiferromagnet Mn 3 Si(TN~23K) to the ferromagnet Fe 3 Si(TC~850K). As a 

characteristic point, Mn3Si shows anomalous magnetic excitations so-called “chimney-type” ones, 

which is difficult to understood by normal spin waves, while Fe3Si shows typical ferromagnetic 

spin wave excitations. Our final goal is to clarify how the spin dynamics qualitatively changes from 

antiferromagnet to ferromagnet in this (Mn,Fe)3Si system, so that a deep insight into the origin 

of magnetism would be gained. The purpose of current work is to grow high quality large single 

crystals of Mn 3-x Fe x Si for inelastic neuron scattering experiments, which can reveal generalized 

magnetic susceptibility directly. Besides, for accurate measurement of bulk properties, such as 

electric resistivity ρ(T) and magnetic susceptibility χ(T) , minimizing amount of impurities is 

important. So far, we have succeeded in growing large single crystals of x=0, 0.2, 0.6, 1.0, and 

1.5 by the Bridgman method. At present, an impurity phase (several-% order) is still observable 

in X-ray powder diffraction patterns. In this work, we report the details of single crystal growth of 

Mn 3-x Fe x Si, assignment of impurity phase,and resultant χ(T), and ρ(T). 

QG19 

AC magnetic measurement of LiFeAs at pressures up to 5.2 GPa: 

Verification of the relation between Tc and structural parameters 

Shuhei Yamaguchi 1 , Nobuhiro Yamaguchi 1 , Masaki Mito 1 , Hiroyuki Deguchi 1 , 

Michael. J. Pitcher 2 , Peter. J. Baker 3 , Stephen. J. Blundell 3 , Dinah. R. Parker 2 and 

Simon. J. Clarke 2 

1 Fac. of Eng, Kyushu Inst. of Tech, Japan 

2 Dep. of Chem, Univ. of Oxford, United Kingdom 

3 Dep. of Phys, Univ. of Oxford, United Kingdom 

We have already conducted AC susceptibility measurements at pressures up to 1.5 

GPa and X-ray diffraction experiment up to 20 GPa for a 111 type of iron-based 

superconductor, LiFeAs[1]. Now, we have enlarged the pressure range of the AC 

susceptibility measurement for the same sample up to 5.2 GPa. The superconducting 

transition temperature Tc decreased from 17 K at 0 GPa to 10 K at 5.2 GPa. Tc has 

been related to two structural parameters, an As-Fe-As bond angle α and the height of 

As from the Fe layers (hAs): Lee et al. have suggested that Tc has the highest value 

at the optimal α of 109.47°[2]. Kuroki et al. have suggested that Tc increases with 

increasing hAs[3]. According to our previous study, α changes from 101.5° at 0 GPa to 

97.8° at 17 GPa, and hAs changes from 0.154 nm at 0 GPa to 0.156 nm at 17 GPa. The 

present pressure-induced decrease in Tc is not explained by the change in hAs, but is 

qualitatively consistent with the change in α. 

[1] M. Mito et al., J. Am. Chem. Soc., 131 (2009) 2986. [2] C.H. Lee et al., J. Phys. Soc. Jpn. 77 

(2008) 083704. [3] K. Kuroki et al., Phys.Rev.B 79 (2009) 224511. 

QG20 

QG21 

QG22 


Fundamental Magnetism of Fe-P Alloys and Fe3P Compounds: A 

density functional study 

Won Seok Yun, Jee Yong Lee and In Gee Kim* 

Graduate Institute of Ferrous Technology, POSTECH, Korea 

Phosphorus (P) is quite harmful on the mechanical properties of steel. For instance, 

the decrease of the strength and plastic properties of G13L steel is nearly half when it 

contains 0.065 wt.% P compared to the case of 0.028 wt.% P steel. On the contrary, P 

is an important component in the making phosphor bronze which enhances wear and 

water corrosion resistant. On the purpose of solid solution strengthening, P containing 

interstitial free steel is very important in the automotive industry due to their excellent 

deep drawability. However, there is no systematic first-principles study done for 

understanding the Fe-P alloys and Fe3P compounds. Thus, we investigated fundamental 

magnetic and thermodynamic properties of ferrites with the various P concentrations 

(Fe 1-xP x alloys, x = 0.037, 0.0625, and 0.125) and (L12, D03, and I-4 structured) Fe 3P 

compounds using the highly precise all-electron full-potential linealized augmented 

plane wave method. As a result, the ferromagnetic state for I-4 structured Fe 3P 

compound is more stable than the nonmangetic one by energy difference of about 

809 meV. The calculated magnetic moments are rather overestimated compared to the 

neutron diffraction study. Detailed discussion on the magnetic and thermodynamic 

properties of Fe 1-xP x alloys and Fe 3P compounds will be given. 

Analysis of spin-polaron formation in Hund lattices 

Yesenia Arredondo 1 *, Emmanuel Vallejo 2 , Oracio Navarro 1 and Michel Avignon 3 

1 Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Mexico 

2 Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Coahuila, Mexico 

3 Institut Neel, CNRS and Universite Joseph Fourier, France 

The ferromagnetic Kondo lattice model, also known as Hund lattice model, is a well-established model to 

study the interplay between charge and spin degrees of freedom in strongly correlated fermionic systems 

such as transition-metal oxides. Their electronic, magnetic and transport properties have displayed interesting 

physics such as the phenomenon of magnetoresistance [1]. Their properties depend as well strongly on the 

doping of the materials, which leads to formation of magnetically ordered regimes [2]. In our work, we study 

numerically the formation of spin-polarons in one-dimensional systems. We consider a Hund lattice model 

where a conducting band is coupled to a background of localized spins interacting antiferromagnetically with 

coupling constant J. Even though the zero-temperature of such lattice model has been intensively studied [3 

,4], the physics of its phase diagram is still not exhausted. We investigated the ground state phase diagram 

as a function of the exchange coupling J and as a function of the band filling and found different evolving 

magnetic orderings. We report measurements of static properties such as spin structure factor. We study the 

quasi-particle formation and phase separation using the density-matrix renormalization group method, which 

is a highly efficient method to investigate quasi-one-dimensional strongly correlated systems[5]. 

1. D. D. Sarma, P. Mahadevan, T. Saha-Dasgupta, S. Ray, A. Kumar, Phys. Rev. Lett. 85, 2549(2000). 2. T. 

Kumar, M. Greenblatt. In Functional Oxides, John Wiley & Sons, 2010. 3. E. Vallejo, F. Lopez-Urias, O. 

Navarro, M. Avignon, Solid State Commun. 149, 126(2009). 4. D. J. Garcia, K. Hallberg, B. Alascio, M. 

Avignon, Phys. Rev. Lett. 93, 177204(2004). 5. U. Schollwock, Rev. Mod. Phys. 77, 259(2005). 

Chiral magnetic orders in chiral helimagnet Cr1/3NbS2 Yoshihiko Togawa 1 *, Tsukasa Koyama 2 , Shigeo Mori 2 , Yusuke Kousaka 3 , Jun 

Akimitsu 3 , Sadafumi Nishihara 4 , Katsuya Inoue 4 , Alexander Sasha Ovchinnikov 5 and 

Jun-ichiro Kishine 6 

1 

Nanoscience and Nanotechnology Research Center (N2RC), Osaka Prefecture 


2 


3 

Department of Physics, Aoyama Gakuin University, Japan 

4 

Department of Chemistry, Hiroshima University, Japan 

5 

Department of Physics, Ural Federal University, Russia 

6 

Graduate School of Arts and Sciences, The Open University of Japan, Japan 

We directly present that chiral magnetic orders emerge in chiral helimagnet Cr 1/3NbS 2 in small magnetic fields 

by means of low-temperature Lorenz transmission electron microscopy and small-angle electron diffraction 

technique. Based on precise analyses in both real and reciprocal space, we undoubtedly demonstrate that chiral 

magnetic soliton lattice (CSL) develops from chiral helimagnetic structure (CHM) with increasing the spatial 

period from 48 nm toward infinity in rising magnetic fields perpendicular to the helical axis. CSL and CHM do 

not exhibit any structural dislocation, indicating their high stability and robustness. This is because chiral magnetic 

orders are macroscopically induced by the uniaxial Dzyaloshinkii-Moriya (DM) exchange interactions that is 

allowed in Cr 1/3NbS 2 hexagonal crystals belonging to noncentrosymmetric chiral space group. Theoretical sides 

of this talk will be given in this topic category by Prof. Jun-ichiro Kishine from the Open University of Japan. 

[1] Y. Togawa, T. Koyama, K. Takayanagi, S. Mori, Y. Kousaka, J. Akimitsu, S. Nishihara, K. Inoue, A. 

S. Ovchinnikov, and J. Kishine, to appear in Phys. Rev. Lett. 


Poster Tuesday



QG23 

ESR study of AFM - Ordering in the orthorhombic CuMnAs 

Yuriy Vladimirovich Goryunov 1 * and Alexandr Nikolaevich Nateprov 2 

1 

Russian Academy of Sciences, Kazan Physical-Technical Institute of the Russian 

Academy of Sciences, Russia 

2 

Academy of Sciences of Moldova, Institute of Applied Physics, Moldova 

At the present time the Mn based compounds with elements of I or V group were 

studied intensively as advances materials for spintronic. One from such compounds 

is CuMnAs. CuMnAs is ordered antiferromagneticaly above room temperature. We 

have studied electronic spin resonance (X-band) in this compound at temperature 

range 10 - 400 K At all temperature we observed symmetric Lorentz’s shape resonance 

lines from Mn 2+ ions with g - factor 2.00. The lineswidth increase in 2 times at 

temperature decreasing to 10 K. The second line with a g-factor of 2.55 has appeared 

in the spectrum at temperatures below 60 K Non resonant absorption was observed 

for powder samples. We interpreted our results in terms Mn-Cu-Mn and Mn-As- 

Mn indirect superexchange interaction. Work was supported by Grants of RFBR and 

Presidium of the RAS. 

[1] F. Maca, J. Masek,O. Stelmakhovych, et al., ArXiv: 1102.5373v1 [cond-mat. matrl-sci] 25 

Feb 2011 [2] T. Jeong, Ruben Weht,W. E. Pickett, Phys.Rev. B 71, 184103 (2005) [3] J. Boeuf, C. 

Pfleiderer, A. Faißt, Phys.Rev. B 74, 024428 (2006) [4] T. Jungwirth, V. Novak, X. Martı, M. Cukr, et 

al., Phys.Rev. B 83, 035321 (2011) 

QG24 

Elastic properties and stability of Heusler compounds 

S.-c. Wu*, S. S. Naghavi, G. H. Fecher and C. Felser 

Max Planck Inst. for Chem. Phys. of Solids; Inst. for Inorg. and Analy. Chem., Uni. 

Mainz, Germany 

The physical properties of Heusler compounds which are promising materials for 

spintronics are important. Various Heusler compounds are investigated with respect 

to their malleability and stability. The elastic constants are calculated by applying 

isotropic strain in different ways to the cubic crystal. We used FP-LAPW implemented 

in Wien2K to calculate the elastic constants as well as further physical properties 

(bonding, hardness, velocity of sound, Debye temperature, etc.) that can be derived 

from the elastic constants. The result of the cubic elastic anisotropy can be used to 

decide the structural stability. Zener's ratios of the most stable compounds are in the 

range of 1.0 < Ae < 2.5. Ae < 0 is not stable and Ae = 0 is isotropic. We observed phase 

transitions in some of Heusler compounds with Ae < 0. It is shown that calculating 

elastic constants provides an estimate for studying phase transitions. 

QG25 

Electronic and magnetic properties of ferromagnet/dilute-magnetic 

semiconductor interfaces 

Alessandra Continenza* and Gianni Profeta 

Physics, Universita' degli studi dell'Aquila, Italy 

A. Continenza and G. Profeta Experimental findings [1-4] report exchange-bias effects 

at the Fe/GaMnAs together with interesting possible magnetic prossimity effects at the 

interface between the ferromagnetic (FM) material and the dilute semiconductor (DMS). 

In this work we perform ab-initio calculations of different FM/DMS geometries 

(superlattice systems and periodic slab) for Fe/Ge:Mn and Fe/GaAs:Mn interfaces. We 

examine different interfaces to assess the most stable structures, the magnetic coupling 

between the magnetic overlayer and the Mn dopant atoms and how the ferromagnetic 

overlayer affects the interaction between two Mn atoms dispersed in the semiconductor 

matrix. An antiferromagnetic coupling between the overlayer Fe and the Mn is found 

for Mn close to the interface layers, fading away with the distance of the Mn atom 

from the interface. A study of how the magnetic coupling between overlayer and dilute 

Mn and between dilute Mn's at different locations is performed and discussed. We find 

a rather large magnetic coupling enhancement in the case of Ge while the situation for 

GaAs looks to be much more complex due to chemical effects at the GaA/Fe interface. 

Results are discussed in terms of local densities of states, magnetic moments and total 

energies. 

[1] Phys. Rev. Lett. 101, 267201 (2008) [2] Phys. Rev. B 81, 104402 (2010) [3] Phys. Rev. B 

81.035211 (2011) [4] J. Appl. Phys. 109, 07C505 (2011) 


QG26 

Mn-Sublattice of YbMn2Si2 Stewart J Campbell 1 *, Michael Hofmann 2 , Richard A Mole 3 , Karel Prokes 4 , Jianli Wang 5 and Dirk Wallacher 6 

1 

School of Physical, Environmental and Mathematical Sciences,ADFA, The University of New South 

Wales, Australia 

2 

Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitat Munchen, Germany 

3 

Bragg Institute,, ANSTO, Australia 

4 

Helmholz Zentrum Berlin, Lise Meitner Campus, Germany 

5 

Institute for Superconducting & Electronic Materia, University of Wollongong, Australia 

6 

Helmholz Zentrum Berlin,, Lise Meitner Campus, Germany 

The instability of the f shell in Yb and the small energy difference between the Yb 2+ divalent and 

Yb 3+ trivalent states, has led to the wide range of physical and magnetic properties exhibited by ytterbiumbased 

intermetallic compounds. The ranges of effects are linked with many physical states such as: mixed 

valence, Kondo effect, heavy fermions, spin wave excitations, superconductivity and magnetic quantum 

critical point [e.g. 1]. Trivalent YbMn 2Si 2 exhibits a collinear antiferromagnetic AFil structure below TN1 = 

526(4) K with a doubling of the magnetic c-lattice below TN2 = 30(5) K; this structure of the Mn-sublattice 

would therefore be expected to result in different environments for Yb atoms in the doubled unit cell [2]. 

However 170Yb Mossbauer studies led to the conclusion that the observed spectra are inconsistent with the 

cell-doubling [3]. To clarify this discrepancy, we have re-investigated the magnetic behaviour of YbMn2Si2 

over the temperature range ~0.4-50 K using the E6 neutron diffractometer, HZB. The high density of 

diffraction patterns confirm the cell doubled magnetic behaviour of the Mn-sublattice below 27.3(2) K with 

the onset of the satellite reflections (propagation vector k = 00½) described well by a power law. 

[1] C. Klingner, C. Krellner, M. Brando, C. Geibel, F. Steglich, D. V. Vyalikh, K. Kummer, S. Danzenbacher, S. L. Molodtsov, and C. 

Laubschat, T. Kinoshita, Y. Kato, and T. Muro, Phys. Rev. B 83, 144405 (2011). [2] M. Hofmann, S.J. Campbell, A.V.J. Edge and A.J. Studer, J. 

Phys.: Condens. Matter 13, 9773 (2001). [3] D. H. Ryan, J. M. Cadogan, and A.V.J. Edge, J. Phys.: Condens. Matter 16, 6129 (2004) 

QG27 

Electronic structures and magnetic properties of full and half Fe-Mn- 

Ga Heusler alloys 

Y. V. Kudryavtsev 1 , N.v. Uvarov 1 , J. Dubowik 2 , I.n. Glavatskyy 3 , Y. J. Yoo 4 and Y. P. Lee 4 * 

1 G.V.Kurdumov Institute of Metal Physics NAS of Ukraine, Ukraine 

2 Institute of Molecular Physics, PAS, Poland 

3 Helmholtz Centre Berlin for Materials and Energy, Germany 

4 Dept. of Physics, Hanyang University, Korea 

Electronic and magnetic structures of bulk and film Fe 2MnGa and FeMnGa alloys near 2:1:1 and 1:1:1 

stoichiometric compositions have been investigated theoretically and experimentally. It was experimentally 

found that unlike most of full stoichiometric Heusler compounds, bulk Fe 50,4Mn 24,2Ga 25,4 alloy with 

the Curie temperature of 800 K and saturation magnetization of 4.86 μB/f.u. crystallizes in the facecentered-cubic 

(FCC) ordered lattice of L12 (Cu 3Au)-type with small admixture of B2-phase. According 

to results of our first-principle calculations of full electron energy ferromagnetic metallic FCC phase 

(μFCC=6.11 μB/f.u.) is energetically more preferable than ferrimagnetic half-metallic phase with L21 type 

of structure (μL21=2.04 μB/f.u.) or ferrimagnetic metallic FCC phase (μFCC=0.48 μB/f.u.). Metamagnetic 

transition in Fe 50,4Mn 24,2Ga 25,4 alloy from antiferromagnetic to ferromagnetic phase was observed at low 

temperatures. Bulk Fe 33.5Mn 32.0Ga 34.5 alloy has hexagonal structure and saturation magnetization at T=15 

K of μ=3.00 μB/f.u. and the Curie temperature of 453 K. Magnetic properties of Fe 33.6Mn 32.9Ga 32.8 alloy 

films strongly depend on their structure. Atomic disorder in amorphous state significantly reduces the film 

magnetization nearly to zero at room temperature. Depending on deposition conditions, unlike the bulk 

alloy, crystalline Fe 33.6Mn 32.9Ga 32.8 alloy films exhibit BCC- or FCC-ordering that result in anomalous 

temperature dependencies of magnetization in low-temperature region. 

QG28 

Microscopic analysis of magnetic orders in MnP single crystals 

Tsukasa Koyama 1 , Shin-ichiro Yano 2 , Yoshihiko Togawa 3 , Yusuke Kousaka 2 , Shigeo 

Mori 1 , Jun-ichiro Kishine 4 and Jun Akimitsu 2 

1 


2 

Department of Physics, Aoyama Gakuin University, Japan 

3 

Nanoscience and Nanotechnology Research Center, Osaka Prefecture University, 

Japan 

4 

Graduate School of Arts and Sciences, The Open University of Japan, Japan 

Manganese phosphide (MnP) has been extensively studied because of its richness of magnetically 

ordered phases in the magnetic phase diagram. In this study, as a first step to understand the mechanism 

of the magnetic phase transition from the ferromagnetic (FM) phase to the proper screw spiral phase 

or FAN phase, we have studied FM structures in the FM phase of MnP single crystals by means of 

low-temperature Lorentz transmission electron microscopy and small-angle electron diffraction[1]. 

In Lorentz Fresnel micrographs, striped FM domain structures were observed in external magnetic 

field less than 10 Oe in the specimens with the ab-plane in the plane of the specimen. From real- and 

reciprocal-space analyses, it was undoubtedly identified that striped FM domains oriented to the c-axis 

appear with Bloch-type domain walls in the b direction and arrange regularly along the a-axis with 64 

nm separation. Moreover, the magnetic chirality reverses in alternate FM domain walls. These specific 

spin configuration of striped FM domains will affect the magnetic phase transition from the FM phase 

to the proper screw spiral phase at the low temperature or the FAN phase in the magnetic field in MnP. 

[1] T. Koyama, S. Yano, Y. Togawa, Y. Kousaka, S. Mori, K. Inoue, J. Kishine, and J. Akimitsu, 

submitted.

QH01 

Structural and magnetic properties of Fe2Mn0.5Cu0.5Al Nanocrystalline 

Alloys 

Dwi Nanto 1 , Dong-seok Yang 2 , Suhk-kun Oh 1 and Seong-cho Yu 1 * 

1 

Dept. of Physics, BK 21 Physics Program and Dept. of Physics, Chungbuk National 

University, Cheongju, 361-763, Korea 

2 

Dept. of Physics Education, Physics Division, Chungbuk National University, 

Cheongju, 361-763, Korea 

We synthesized Fe 2Mn 0.5Cu 0.5Al nanocrystalline alloys by mechanical alloying 

technique and studied as a function of milling time. The milling times were 1, 3, 6, 9, 

and 24 hrs. The effect of milling time on structure formation was investigated by X-ray 

Diffraction (XRD), and magnetic properties was investigated using vibration sample 

magnetometer (VSM). Alloy nature of Fe 2Mn 0.5Cu 0.5Al was confirmed after 24 hrs. The 

crystallite size after 24 hrs of milling time was estimated using Scherer formula, and 

the value was 24 nm. Magnetic saturation was decreased with increased milling time, 

which seemed be due to co-existence of Mn and Cu atoms. The magnetic saturation 

was 86.19 (emu/gr) and the coercivity was 376.59 Oe after 24 hrs of milling time. The 

coercivity (Hc) was increased with milling time presumably due to magnetic domain 

growth towards stable structure. Keywords: Heusler compound, nanocrytalline 

References: [1] Tanja Graf, Claudia Felser, Stuart S.P. Parkin, Progress in Solid State Chemistry 

39 (2011) 1-50 [2] Shane Stadler1, Mahmud Khan1, Joseph Mitchell1, Naushad Ali1, Angelo M. 

Gomes2, Igor Dubenko3, Armando Y. Takeuchi3, and Alberto P. Guimaraes3 Appl. Phys. Lett. 88, 

192511 (2006) 

QH02 

Antiferromagnetic resonance in the one-dimensional magnet 

IPACu(Cl 1-xBr x) 3 (x=0.83) 

Takahito Fujita 1 , Masayuki Hagiwara 1 and Hirotaka Manaka 2 

1 KYOKUGEN, Osaka university, KYOKUGEN, Osaka university, 1-3 

Machikaneyama, Toyonaka, Osaka 560-8531, Japan 

2 Graduate School of Science and Engineering, Kagoshima University, Graduate 

School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, 

Kagoshima 890-00, Japan 

Low-dimensional antiferromagnets with a small spin value exhibit various fascinating 

properties. IPACuCl 3 and IPACuBr 3 (IPA: isopropyl-amine) having magnetic Cu 2+ (spin 

S=1/2) ions form the ladder chain in the b plane. The ground states of IPACuCl 3 and 

IPACuBr 3 are considered to be the Haldane state [1] and the singlet dimer state [2]. It 

was reported that IPACu(Cl xBr 1-x) 3 (0.44 < x



QH07 

Effect of doped Mn ions in thermoelectric material of Mg 3Sb 2 

Soo Hyun Kim 1 , Chung Man Kim 1 , Junpei Kajino 2 , Toshiro Takabatake 2 and Myunghwa 

Jung 1 * 

1 Physics, Sogang university, Korea 

2 Physics, Hiroshima University, Japan 

Spin caloritronics is about the physics that control of heat, charge and spin currents in 

structures, devices, and materials. Here we focus on the spin-related thermoelectric 

properties and study the effect of magnetic ion doping on the thermoelectric material 

of Mg 3Sb 2. We have synthesized single crystals of Mg 3Sb 2 and Mn-doped Mg 3Sb 2 by 

using Bridgeman method. The X-ray diffraction data show that the crystals are singlephased 

and c-axis oriented. In order to illustrate the thermoelectric performance, we 

have measured the seebeck coefficient (S), electrical conductivity (σ), and thermal 

conductivity (κ) as a function of temperature. The efficiency of thermoelectric 

performance is dominated by the figure of merit, ZT=S 2 ∙σ∙T/κ. The obtained S, σ, 

and κ values at 300K are 600 μV/K, 16 S/m, and 3.5 W/mK, respectively for Mg 3Sb 2. 

Because of the lower σ, the ZT value is estimated to be small. However, by doping 

Mn ions into Mg 3Sb 2, we find the electrical properties to be improved. We will 

discuss more about the optimal condition of Mn doping rate in Mg 3Sb 2 to promote the 

thermoelectric performance. 

QH08 

X-ray diffraction study on crystal structure of Mn 1.8Co 0.2Sb under high 


Hiroki Orihashi 1 *, Daisuke Mitsunaga 1 , Masahiko Hiroi 1 , Yoshifuru Mitsui 2 , Kohki 

Takahashi 2 , Kazuo Watanabe 2 and Keiichi Koyama 1 

1 Graduate School of Science Engineering, Kagoshima University, Japan 

2 HFLSM, IMR, Tohoku University, Japan 

Measurements of magnetization, electrical resistivity and high field X-ray powder 

diffraction (XRD) were carried out for polycrystalline Mn 1.8Co 0.2Sb in magnetic 

fields up to 5 T in 4.2-300 K temperature range, in order to investigate the structural 

properties affected by magnetic fields. In a zero field, the compound shows the firstorder 

magnetic transition from the ferrimagntetic (FRI) to antiferromagnetic (AFM) 

states at Tt = 145 K with decreasing temperature. By applying magnetic fields of 5 T, 

Tt decreased to 60 K with thermal hysteresis of 35 K. From the XRD measurements, 

not only the AFM phase but also the residual FRI phase was confirmed even at 10 K 

in cooling process under 5 T. Results obtained indicate that the residual FRI phase is 

kinetically arrested [1]. 

[1] H. Orihashi et al. Mater. Trans. [Selected Papers from JIM Fall Meeting(2011)] 76 (2011) in 

press 

QH09 

Emergence of Ferromagnetism under pressure in (Mn 1-xFe x) 3GaN 

S. Iikubo 1,6 , T. Inagaki 2 , K. Takenaka 2 , K. Matsubayashi 3 , Y. Uwatoko 3 , H. Takagi 4 , 

and H. Ohtani 5,6 

1 Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology 

2 Department of Crystalline Materials Science, Nagoya University 

3 Institute for Solid State Physics University of Tokyo 

4 RIKEN (The Institute of Physical and Chemical Research) 

5 Department of Materials Science and Engineering, Kyushu Institute of Technology 

6 JST, CREST 

The recent development of “metallic” antiperovskite nitrides Mn 3AN, where A is a metal or a 

semiconducting element, has promoted research toward practical use. We found an intimate 

relationship between the large magneto-volume effect (MVE) in cubic Mn 3AN and the Γ 5g -type 

antiferromagnetic (AF) ordering. As a tunable thermodynamic parameter, the external pressure 

may play an important role in this system, because it can affect not only the crystal structure but 

also the magnetic structure. We report the pressure effect on the stability of magnetic structure of 

(Mn 1-xFe x) 3GaN. 

In this system, it was reported that a few percent of Fe dopants at the Mn sites alters the AF spin 

structure of Mn 3GaN and induces a first-order antiferromag-netic-ferromagnetic phase transition. 

We have measured the magnetization of (Mn 1-xFe x) 3GaN with x=0, 0.05 and 0.07 and Mn 3Ga(N 1yC 

y) with y=0, 0.05 and 0.1 under pressure up to 1.3 GPa. A magnetic transition from an AF to an 

ferromagnetic (FM) state with spontaneous magnetization is observed under pressure. Especially, 

a spontaneous magnetization in Mn3GaN is 0.24 μB per Mn under pressure. The application of 

pressure increases the magnetization in the FM phase for all these compounds. 


QH10 

First-principles-calculations of the magnetic anisotropy energy of 

FeCo and FeNi alloys 

Masanori Enoki 1 , Satoshi Iikubo 2 and Hiroshi Ohtani 3 

1 

Graduate School of Engineering, Kyushu Institute of Technology, Japan Science and 

Technology CREST, Japan 

2 

Graduate School of Life Science and Systems Engineering, Kyushu Institute of 

Technology, Japan Science and Technology CREST, Japan 

3 

Department of Materials Science, Kyushu Institute of Technology, Japan Science 

and Technology CREST, Japan 

The calculations of T.Burkert et at. predict an unusually large magnetic anisotropy energy (MAE) 

of ~700 μeV/atom for the Fe 0.4Co 0.6 random alloy at a ratio of 'c/a'[1]. This result suggests that other 

transition metal alloys are also candidate for emerging a high MAE with altering the 'c/a'. In order 

to seek new design of materials, we research MAE and electronic structures for Fe-Co and Fe-Ni 

alloys with using the first-principles-calculations. The calculations were carried out using the VASP 

code. At first, we optimized the length of lattice constant 'a' against the fixed 'c/a' at range of 1.10- 

1.35. The MAE were evaluated by subtracting the energy with polarized spin direction parallel to 

[100] from that to [001]. For the Fe-Co alloy, the estimated MAE has maximum at c/a~1.25 and 

Fe 0.5Co 0.5, which is roughly consistent with the previous result of Burkert et al. On the other hand, 

Fe-Ni system has the high MAE (~300 μeV/atom) is found at the Fe 0.75Ni 0.25. We will present the 

origin of the large MAE from the electronic structures in these systems. 

[1]T. Burkert et al. Phys. Rev. Lett. 93 027203 (2004) 

QH11 

Tuning the magnetic properties of amorphous FeZr thin by hydrogen 

implantation 

Atieh Zamani 1 *, Anders Hall 2 , Per Nordblad 3 , Bjorgvin Hjorvarsson1 and Petra 

Jonsson1 

1 Physics and Astronomy,Material Physics, Uppsala University, Sweden 

2 School of Information and Communication Technology (ICT), KTH, Sweden 

3 Department of Engineering Sciences,, Uppsala University, Sweden 

Amorphous FeZr alloys order ferromagnetically, with a maximum in the ferromagnetic 

transition temperature near 240K for Zr contents between 10-20 at.% . Interestingly, 

hydrogen can be introduced into the alloy, enhancing its Curie temperature, magnetic 

moment and soft magnetic properties. In order to understand the magnetism of the 

Fe(Zr) binary system, and the e ect of hydrogen on the magnetic interaction, we have 

investigated in details the magnetic properties of amorphous thin lms of Fe(Zr). Fe1 

xZrx lms with compositions x=7.5, 9.5, 11.5, 12.5 and 13.5 at.% were grown by cosputtering 

on Si substrate in ultra high vacuum (UHV) conditions. The compositions, 

structural and magnetic properties of the lms were investigated by Rutherford 

Backscattering spectrometry (RBS), X-ray di raction, and SQUID magnetometery 

respectively before and after hydrogenation. The hydrogen implanted samples show 

an increased value of the Curie temperature with increasing hydrogen content. The 

magnetization curves at low temperature show a continuous increase with increasing 

eld also at quite high temperature con rming the presence of random anisotropy. This 

anisotropy is heavily suppressed by hydrogen implantation. Keywords: Amorphous 

Fe(Zr), Magnetization, H-implantation 

QH12 

Normal and intrinsic anomalous Hall effect in NbFe 2 

Sven Friedemann 1 *, William J Duncan 2 , Andreas Neubauer 3 , Manuel Brando 4 , 

Christian Pfleiderer 3 and F Malte Grosche 1 

1 Cavendish Laboratory, University of Cambridge, United Kingdom 

2 Department of Physics, Royal Holloway University of London, United Kingdom 

3 Physik Department E21, Technical University Munich, Germany 

4 Max Planck Institute for Chemical Physics of Solids, Dresden, Germany 

Hall effect studies are a powerful probe of the Fermi surface of metals via the normal 

contribution whilst the anomalous contribution may give substantial insight into spinorbit 

interactions. Here, we present Hall effect measurements on selected samples of 

the band magnet system NbFe 2. In the dilution series Nb 1-yFe 2+y composition tuning 

allows to access various magnetic ground states including a complete suppression at 

a quantum critical point. We observe normal and anomalous contributions in the Hall 

effect. Consistent analysis of the anomalous contribution, however, is only possible 

for Fe-rich Nb 0.985Fe 2.015 featuring a ferromagnetic ground state. Here, a positive 

normal Hall coefficient is found at all temperatures with a moderate maximum at the 

spin-density-wave transition. The anomalous Hall effect is covered by an intrinsic 

(Berry-phase) contribution which is constant below the ordering temperature TC and 

continuously vanishes above TC. For samples with antiferromagnetic ground state, i.e., 

stoichiometric NbFe 2 and Nb-rich Nb 1.01Fe 1.99, an additional contribution to the Hall 

resistivity impedes a complete analysis and indicates the need for more sophisticated 

models of the anomalous Hall effect in itinerant antiferromagnets.

QH13 

Magnetovolume effect in the itinerant-electron frustrated magnet 

Fe 3Mo 3N 

Yoshikazu Tabata 1 *, Masaki Yamamoto1 1 Shinsuke Terazawa 1 , Takeshi Waki 1 , Kenji 

Ishida 2 and Hiroyuki Nakamura 1 

1 Department of Materials Science and Engineering, Kyoto University, Japan 


The η-carbide-type compound Fe 3Mo 3N, including the frustrated stella-quadrangula 

Fe-sublattice, is a novel itinerant-electron frustrated magnet and exhibits intriguing 

features such as non-Fermi-liquid behavior without parameter-tuning and sharp 

metamagnetic transition [1]. We performed thermal expansion and magnetostriction 

measurements of Fe 3Mo 3N up to 15 T. A large volume expansion is found at the 

metamagnetic transition field and the magnetovolume coupling constant is estimated 

as about 4 × 10 -3 μB -2 , being the same of magnitude of those of Co Laves phase 

compounds [2]. It indicates that the metamagnetic transition of Fe 3Mo 3N is a typical 

moment-induced-type in nonmagnetic itinerant electron systems. The nonmagnetic 

ground state of Fe 3Mo 3N at zero field is emergent due to the frustration effect built into 

the stella quadrangula lattice. 

[1] T. Waki et al., J. Phys. Soc. Jpn. 79, 043701 (2010).; T. Waki et al., Europhys. Lett. 94, 37004 

(2011). [2] Y. Muraoka et al., J. Phys. Soc. Jpn. 53, 331 (1984). 

QH14 

NMR studies of magnetic properties in the spinel-type Cu(Cr 1-xHf x) 2S 4 

Haruo Niki 1 *, Morihito Oshiro 1 , Saori Nakamura 1 , Ayaka Uechi 1 , Mamoru Yogi 1 , 

Shuji Ebisu 2 and Shoichi Nagata 2 

1 Department of Physics, Faculty of Science, University of the Ryukyus, Japan 

2 Muroran Institute of Materials Research, Japan 

A chalcogenide tiospinel CuCr 2S 4 is a metallic ferromagnet with Tc = 380 K. The 

increase of x for the mixed spinel Cu(Cr 1-xHf x) 2S 4 shows a successive change from 

a ferromagnetic, a re-entrant spin-glass, a spin-glass, and finally to a paramagnetic 

state. A step-like anomaly in magnetization is also found around 160 K in the range 

of 0.50 ≤ x ≤ 0.70 due to a spin crossover phenomenon [1]. In order to investigate 

the magnetic properties of Hf rich side in Cu(Cr 1-xHf x) 2S 4 from a microscopic point 

of view, 63Cu NMR have been carried out between 4.2 and 300 K. Temperature 

dependences of resonance line-width, Knight shift and spin-lattice relaxation time (T1) 

have been measured. Knight shift in the range of 0.50 ≤ x ≤ 0.70 gradually shifts to 

negative side down to 130 K, but rapidly shifts to negative side below 130 K due to 

the core polarization of d conduction electrons. Temperature dependence of 1/T1T in 

the range of 0.50 ≤ x ≤ 0.70 obeys the Korringa relation (T1T = constant) down to 130 

K, as expected in a Pauli-paramagnetic metallic state. However, the values of 1/T1T 

=constant abruptly change between 130 and 90 K, and keep constant below 90 K. 

[1] F. Kariya, K. Ebina, K. Hasegawa, K. Koshimizu, B. Wuritunasitu, K. Hondou, S. Ebisu and S. 

Nagata, J. Solid State Chem. 182 (2009) 2018. 

QH15 

Relationship between microstructure and magnetic properties of nanoscale 

magnetic particles formed in a Cu-Ni-Co alloy 

Donghae Lee 1 , Mahoto Takeda 1 *, Sung Kang 2 and Takahiro Moriki 1 

1 Department of materials engineering,Yokohama national university, Japan 

2 Research Institute of Industrial Science & Technology(RIST), Korea 

The discovery of Giant Magnetic Resistance (GMR) has invoked strong interest to relationship 

between microstructure and magnetic properties of nano-scale particles. The magnetic 

properties of nano-scale particles are strongly dependent on their structures, particle sizes, 

shapes, and interparticle distances particularly in granular magnets. The present study aimed 

to investigate the relationship between the microstructure and the magnetic properties of 

granular Cu-Ni-Co alloys, using transmission electron microscope (TEM), a superconducting 

quantum interference device (SQUID) magnetometer and thermo gravimetric-differential 

thermal analysis (TG-DTA). The present TEM observations revealed a specific feature that 

spherical ferromagnetic precipitates are transformed into cubic ones, and subsequently two 

or more cubic precipitates are aligned along the orientation of a Cu matrix, which 

feature was significantly different from previous recognition to conventional precipitation. 

SQUID measurements shows that the magnetic property of the specimen changes from superparamagnetism 

to ferromagnetic in character with increasing isothermal annealing period 

from M-T curves. The present TG/DTA curves showed that a ferromagnetic to paramagnetic 

transition occurred at low temperatures (~950K) but paramagnetic to ferromagnetic transition 

at high temperatures(600~700K). This suggests that the coalescence of magnetic atoms and 

accordingly the Curie point are sensitive to annealing temperature. 

QH16 

QH17 

QH18 


Magnetic study of mechanically deformed FeAlSi alloys 

Estibaliz Legarra 1 , Estibaliz Apinaniz 2 , Damian Martin-rodriguez 3 , Jose Javier 

Garitaonandia 4 and Fernando Plazaola 1 

1 Department of Electricity and Electronics, Basque Country University, UPV/EHU, p. c. 644, 48080, 

Bilbao, Spain 

2 Department of Applied Physics I, Basque Country University, UPV/EHU, Alameda Urquijo s/n, 48013, 

Bilbao, Spain 

3 Julich Centre for Neutron Science and Institute for Complex Systems, Forschungszentrum Julich GmbH, 

52425 Julich, Germany 

4 Department of Applied Plysics II, Basque Country University, UPV/EHU, p. c. 644, 48080, Bilbao, Spain 

The mechanical deformation of Fe-Al alloys produces order-disorder transition that induces an enlargement 

of the magnetism of the alloys. It has been demonstrated that this enlargement is related to atomic disorder and 

cell volume increase [1]. The behaviour of the saturation magnetization with milling and Si content in Fe 75Al 25xSi 

x anf Fe 70Al 30-xSi x alloys is similar to the behaviour shown by the mean magnetic hyperfine field. Their 

values increase with disordering in alloys with low Si content, but decrease in alloys with higher Si content. 

The behaviour observed indicates clearly that the introduction of Si in the binary Fe 75Al 25 and Fe 70Al 30 alloys 

opposes the magnetic behaviour induced by Al in the magnetism of Fe. These opposite behaviours are related to 

the lower increase of the lattice parameter with disorder for FeSi alloys. Besides, when plotting the normalized 

variation of lattice parameter produced by the disorder versus the normalized variation of magnetization we 

observe a linear relationship, showing that lattice parameter and magnetic properties are related. The study of 

the hyperfine fields also indicates that there is a redistribution of non-ferrous atoms around Fe atoms with the 

disordering, indeed, there is an inversion of the behaviour of the hyperfine fields. 

[1] A. Hernando, X. Amils, J. Nogues, S. Surinach, M. D. Baro, and M. R. Ibarra, Phys. Rev. B 58 11864 (1998). 

The propagation of electromagnetic waves in magnetic with 

ferromagnetic spiral 

Igor Valer'evich Bychkov 1 , Vasily Dmitrievich Buchelnikov 1 , Dmitry Aleksandrovich 

Kuzmin 1 and Vladimir Grigor'evich Shavrov 2 

1 Cheliabinsk State University, Russia 

2 The Institute of Radioengineering and Electronics of RAS, Russia 

Recently, spiral magnetic materials have attracted researchers' attention for their 

unusual physical properties. However, the spectrum and dynamic properties of magnets 

in a phase are not studied enough. In the present work the 

spectrum of the coupled spin and electromagnetic waves in spiral magnetic structure of 

type is investigated. Also the reflection of electromagnetic 

waves from a layer of magnetic having the ferromagnetic spiral and the Faradey effect 

are considered. We use approach L >> a, where L - the spiral period, a - the lattice 

constant. Studies showed that the spectrum of the coupled waves has band structure. 

The band gap depends on the angle of the ferromagnetic spiral, and hence on the 

external magnetic field. The frequency dependence of the reflection coefficient of 

electromagnetic waves from the plate of the magnetic with a ferromagnetic spiral at 

different angles of the helix has been calculated. As the angle increases the opacity 

region broadens and shifts to higher frequencies. Thickening of the plate also leads to 

broadening of the opacity region. The Faraday effect has been observed for different 

frequencies. The angle of plate-of-polarization rotation increases near the band gap. 

The Verdet constant has been calculated. 

Magnetism of sigma-phase Fe-Mo and Fe-Re systems 

Jakub Cieslak 1 *, Stanislaw M Dubiel 1 , Michael Reissner 2 and Janusz Tobola 1 

1 

Academy of Mining and Metallurgy, AGH al. Mickiewicza 30, 30-059 Krakow, 

Poland 

2 

Institute of Solid State Physics, Vienna University of Technology, A-1040 Wien, 

Austria 

Sigma phase exists in five binary systems of the Fe-X type viz. for X = Cr, V, Mo, 

Re and Tc. It is characterized by a lack of chemical order on all five sublattices of the 

tetrahedral unit cell. Until now, the magnetic properties have been known only for 

sigma-FeCr and sigma-FeV systems. The newly discovered low temperature magnetic 

properties of sigma-FeMo and sigma-FeRe phases will be presented and analyzed in 

detail in the whole concentration range in which this phase occurs. In particular, in both 

cases, the observed increase in an average magnetic moment and magnetic ordering 

temperature with increasing of Fe content is evident. Differences in Zero-Field Cooling 

and Field Cooling magnetization measurements suggest the magnetic ordering of 

spin-glass type or a large magnetic anisotropy in the measured samples. Electronic 

structure calculations using the KKR method were carried out for more than a dozen 

semi-ordered unit cells. The results of these calculations show a linear dependence of 

magnetic moments and hyperfine fields of Fe atoms at different sites versus the number 

of Fe atoms being their nearest neighbors. They also suggest a noncollinear magnetic 

structure in some sublattices. 


Poster Tuesday



QH19 

Second order magnetization effects in bcc Fe 

Dominik Legut*, Jaroslav Hamrle and Jaromir Pistora 

Nanotechnology Centre, VSB-Technical University of Ostrava, Czech Republic, Czech 

Republic 

Second order effect in magnetization are becoming an important way of 

characterization of the magnetic samples. One of the examples of second order effect 

in magnetization are anisotropic magnetoresistance (AMR), Voigt effect, quadratic 

magneto-optical Kerr effect (QMOKE) or X-ray magnetic linear dichroism (XMLD). 

All those effects are originating from conductivity (or permittivity) tensor, which 

elements are varying with direction of the sample magnetization. This dependence 

is determined by symmetry arguments describing break of the symmetry by 

magnetization in the crystal. From first principles we have calculated the complete 

angular dependence of all elements of the permittivity tensor with respect to the change 

of magnetization axis in a wide spectral range (from dc to ultraviolet) for a bodycentered 

cubic Fe. The correctness of calculations are verified by careful comparison 

with expected dependences provided by symmetry arguments. The calculations are 

based on density functional theorem utilizing one of the most accurate full potnetial 

augmented plane-wave code. The effect of the spin-orbit interaction for valence and 

semicore states is included as well. 

QH20 

Magnetic structure of nearly equiatomic MnRh alloy 

Yuki Matsuoka 1 and Aya Takasaki 2 

1 Nara Women's University, Japan 

2 Graduate School of Humanities and Sciences, Nara Women's University, Japan 

MnRh shows various kind of magnetic state. The magnetic structure and the transition 

temperature of MnRh are expected to be very sensitive to the atomic composition. 

At the equiatomic composition, this alloy shows antiferromagnetic - paramagnetic 

transition. By increasing Mn ratio, this alloy shows complicated magnetic property, 

ferromagnetic - weak ferromagnetic transition.[1] Yamada et.al. reported that 

antiferromagnetic structure is most stable in this alloy.[2] To determine the magnetic 

structure, we performed neutron diffraction measurements and observed some magnetic 

scattering peaks. The intensities of magnetic scattering peaks were almost same even 

just below the phase transition temperature. On the other hand, magnetization curve of 

same component alloy suggests magnetic phase transition. We attempt to determine the 

magnetic structure and to make magnetic phase diagram of nearly equiatomic MnRh. 

[1] Matsuoka Y, 1995 MA Thesis [2] Yamada H, Shimizu H, Yamamoto K, Uebayashi K, 2006 J.Alloys 

Comp. 415 31 

QH21 

Magnetic and transport properties of Pd 2Mn 1+xIn 1-x Heusler alloys 

Hironari Okada 1 *, Yohei Yamazaki 2 , Takashi Yasuda 1 and Takeshi Kanomata 1 


2 Division of Engineering, Graduate School of Tohoku Gakuin University, Japan 

Recently, it was reported that Ni-Mn-In and Ni-Mn-Sn Heusler alloys having a 

ferromangetically ordered L21 type structure show a magnetic-field-induced reverse 

martensitic transformation associated with a metamagnetic transition [1]. The interplay 

between the martensitic transformation and the magnetic transition gives rise to a 

magnetic-field-induced shape recovery effect and a magnetoresistance effect. Pd 2MnIn 

has an antiferromagnetically ordered L21 type Heusler structure [2], which is different 

from the magnetic ordered state of Ni 2MnIn. In this work, in order to investigate 

the magnetic and transport properties of the antiferromagnetic Heusler alloys, we 

performed magnetization and electrical resistivity measurements for Pd 2Mn 1+xIn 1-x. 

In Pd 2Mn 1+xIn 1-x with x > 0.2, a sudden increase of the resistivity was observed. 

The temperature at which the anomaly of the resistivity appears shifts to the higher 

temperature with increasing Mn content, and no anomaly was detected for the Mn 

content with x = 0.55. The results of powder X-ray diffraction experiment indicate 

that a martensitic phase appears for the Mn content with x = 0.55 at room temperature. 

Therefore, it is considered that the anomalous behavior of the resistivity results from 

the martensitic transformation. 

[1] R. Kaimuma et al, Nature 439 (2006) 957. [2] P. J. Webster and R. S. Tebble, Phil. Mag. 16 (1967) 

347. 


QH22 

Structural and magnetic properties of (Co, Fe, Ni), (Fe, Mg, Zn) and 

(Fe, Mn, Zn) alloys deposited onto Al 2O 3 and SiO 2 

Lonzeche Jean Augustin Lodya 1 *, Adli Beck 2 , Rudelle White 3 , Bongani Xaba 1 , 

Siyanda Lubhelwane 1 , Khuselwa Vundisa 1 and Jeanette Ngubane 1 

1 Research & Development, Sasol Technology, South Africa 

2 Chemistry Department, University of Stellenbosch, South Africa 

3 Chemistry Department, North-West University, South Africa 

Structural and magnetic properties of (Co, Fe, Ni), (Fe, Mg, Zn) and (Fe, Mn, Zn) alloys 

deposited onto Al 2O 3 and SiO 2 supports are reported. The samples were synthesised by ball 

milling and characterised using magnetic measurements (MM), Mossbauer spectroscopy (MS), 

XRD, SEM, TPR and (BET). Granular and irregular shaped particles were formed. MM, MS 

measurements and XRD data revealed the formation of peculiar solid solutions some of them 

having spinel structures. In all the samples small crystallites in a superparamagnetic (SPM) 

state at room temperature were found to coexist with larger ones, their fractions depending on 

the energy imparted during the ball milling process. That is, crystallites were predominantly in 

a SPM state at a relatively high ball-to-powder ratio while larger crystallites were prevalent at 

a relatively low ball-to-powder ratio. The ball milling process resulted also in low surface areas 

and collapse of pores. Further, the existence of strong metal support interactions (SMSI) was 

inferred in all the samples; this rendered reduction difficult and/or led to incomplete reduction. 

Fittings of the Curie-Weiss model to the experimental temperature dependences of AC 

magnetic susceptibility were used to determine the effective magnetic moments associated with 

magnetic cations and the nature of their interactions. 

QH23 

Structure disorder effect of L1 0 FePt within supercell method 

Kazuhiko Uebayashi 

Section of Natural Science, Akita National College of Technology, Japan 

L1 0 FePt alloy is famous for a good candidate of high density magnetic recording 

media. In my previous work[1], I have performed energy-band calculations for the 

L1 0 bulk alloy FePt by using the linear muffin-tin orbital method with atomic sphere 

approximations. This previous calculated study shows that the calculated lattice 

constants and magnetic moments are good agreement with observed ones. The 

experimental stable-magnetic state is ferro magnetic, but in the calculation one of 

the anti-ferro magnetic state is most stable, and the second is ferro magnetic above 1 

mRy/ f.u. The difference between the experimental and calculated result for L1 0FePt 

is known by another work[2]. To improve the difference, I carry out structure-disorder 

band calculation for FePt with supercell method. I assumed that the supercell is as 8 

times large as a formula unit. In the supercell with only one substitution Fe and Pt, 

the most stable state becomes ferro and the difference between ferro and anti-ferro 

magnetic state is about 10 2 mRy. The result indicate that the structure disorder of L1 0 

FePt in the supercell makes ferro magnetic stable with observed lattice constants. 

[1] K. Uebayashi, JOURNAL OF APPLIED PHYSICS 107, 09A733 (2010) [2] G. Brown, 

PHYSICAL REVIEW B 68, 052405 (2003) 

QH24 

Itinerant antiferromagnetism in high-quality single crystal CrB2 

Andreas Bauer 1 *, Alexander Regnat 1 , Christian Blum 2 , Saskia Gottlieb-schoenmeyer 1 , 

Bjoern Pedersen 3 , Sabine Wurmehl 2 , Bernd Buechner 2 and Christian Pfleiderer 1 

1 

Physik-Department E21, Technische Universitaet Muenchen, D-85748 Garching, 

Germany 

2 

Leibniz Institute for Solid State and Materials Research IFW, D-01171 Dresden, 

Germany 

3 

Forschungsneutronenquelle Heinz-Maier Leibniz, Technische Universitaet 

Muenchen, D-85748 Garching, Germany 

Transition metal and rare earth diborides with the hexagonal AlB 2 structure form a series 

of compounds with a remarkably wide range of different electronic ground states. We 

report the properties of isotopically enriched high-purity single crystals of CrB 2 grown by 

optical float-zoning. The temperature dependence of the electric resistivity and specific 

heat provide unambiguous evidence of spin density wave type order with a slightly 

anisotropic charge gap Δ(001) = 230 K and Δ(100) = 212 K, respectively. We also find 

that the Neel temperature of 88.5 K remains unchanged under magnetic fields up to 14 

T, the highest field studied. A detailed neutron scattering study, made possible through 

the use of 99% isotopically enriched 11B, provides for the first time unambiguous 

evidence of antiferromagnetic order, and identifies CrB 2 as a textbook example of itinerant 

antiferromagnetism. In comparison to the properties of other high-quality single crystal 

transition metal and rare earth diborides we have prepared, our studies of CrB 2 shed an 

unexpected new light on the properties of this exciting series of compounds.

QH25 

Magnetic orderings in Fe-intercalated TiX 2 (X=S, Se) 

Seung Ill Hyun and J.h. Shim* 

Chemistry, POSTECH, Korea 

Titanium dichalcogenides shares the same layered structure, except TiO 2. Their 

physical properties, however, are different from each other. TiSe 2, for example, is the 

only compound that bears an unconventional charge-density wave (CDW) transition 

under 200K, whereas the others show no distinct structural distortion.[1] Furthermore, 

Iron-intercalated TiS 2 and TiSe 2 exhibit different types of magnetism. Fe 0.5TiS 2 displays 

a ferromagnetic ordering under 80K, Fe 0.5TiSe 2 shows an antiferromagnetic ordering 

under 135K.[2,3] In order to describe the magnetic interactions between Fe atoms, we 

apply the first principle calculation on Fe 0.5TiX 2 (X=S, Se) and explain the experimental 

observations correctly. We also discuss the origin of different magnetic behaviors based 

on the structural & elemental effect. 

[1] K. C. Woo, F. C. Brown, W. L. McMillan, R. J. Miller, M. J. Schaffman, and M. P. Sears, Phys. 

Rev. B 14, 3242 (1976) [2] N. V. Selezneva, N. V. Baranov, V. G. Pleshchev, N. V. Mushinikov, and 

V. I. Maksimov, Phys. Solid State 53 (2), 329 (2011) [3] N. V. Baranov, V. G. Pleshchev, E. M. 

Sherokalova, N. V. Selezneva and A. S. Volegov, Phys. Solid State 53 (4), 701 (2011) 

QH26 

Non-Stoner Itinerant Ferromagnetism of a Transition Metal Monomer 

Hanhim Kang, Geunsik Lee, P. Dua, Ji-hoon Shim and Kwang S Kim* 

Department of Chemistry, POSTECH, Korea 

We investigated the one-dimensional monomer chain of 3d transition metals ( Fe, Co, 

and Ni ) by ab-initio band structure calculation with quasiparticle GW method [1]. 

We also studied the role of pair hopping interaction on the magnetic properties using 

the extended Hubbard model [2][3]. GW calculation of transition metal monomer 

shows the spin-dependent band width changes as well as spin-dependent transport 

properties in ferromagnetic phase. Such behavior is well described by the extended 

Hubbard model, where the pair hopping enhances the metallic ferromagnetism in onedimension. 

We suggest that the electron correlation effect such as pair hopping usually 

has important role in the metallic ferromagnetism of low dimensional system. 

[1] T. Kotani, M. van Schilfgaarde, and S. Faleev, Phys. Rev. B, 76 (2007). [2] J. Hirsch, Phys. Rev. B. 

59, 6256 (1999) [3] J. Hirsch, Phys. Rev. B. 43, 701 (1991) 

QH27 

Magnetic structure variation with structural phase transition in 

SrMnSb 2 

M. Arshad Farhan, Geunsik Lee and Ji Hoon Shim* 


RMnSb 2 system (R = Alkali Earth Metal) is analyzed by first principle DFT calculation 

using full potential linearized augmented plane wave method while PBE-GGA is used 

to account for the Exchange-Correlation potential. SrMnSb 2 has zig-zag chains of Sb 

ions while BaMnSb 2 has square planes of it. The application of pressure on SrMnSb 2 

leads to a phase transformation from chain like semi-metal phase to BaMnSb 2 like 

Square planner structure showing metallic properties. The density of states for AFM 

SrMnSb 2 changes with the structural phase change indicating a magnetic transition. 

While for a similar chain to square transition in BaMnSb2 accompanying an Insulator 

to Metal transition, no such variation in magnetic structure is observed. 

QH28 

QH29 

QI01 


Magnetoresistance effect of Heusler-type Fe 2VAl single crystal 

Rika Hamada 1 , Hidetoshi Miyazaki 2 * and Yoichi Nishino 1 

1 Department of Frontier Materials, Nagoya Institute of Technology, Japan 

2 Center for Fostering Young and Innovative Researchers, Nagoya Institute of 


The Heusler-type intermetallic compound Fe 2VAl has attracted strong attention because 

of a semiconducting behavior of ρ and a large electronic specific heat coefficient γ, 

14 mJ/(K2mol). The band calculation revealed that the Fe 2VAl was a semimetal and 

nonmagnetic with a pseudogap around the Fermi level [2]. Endo et al. discovered 

the giant magnetoresistance (GMR) effect in the Heusler type alloys Fe 2+xV 1-xAl poly 

crystal of about 30 % for Fe 2.1V 0.9Al at 4.2 K in the field of 55 kOe [3]. Recently we 

have succeeded in fabricating single crystals of Fe 2.1V 0.9Al using Czochralski method 

and investigated their electric and magnetic properties. The temperature dependence of 

GMR is negative below the Curie temperature (TC). The maximum value of GMR is 

about 35 % around the TC. The value of GMR in Fe 2.1V 0.9Al single crystal is similar in 

that of poly crystal. 

[1] Y. Nishino et al., Phys. Rev. Lett. 79, 1909 (1997). [2] G. Y. Guo, G. A. Bottom and Y. Nishino, 

J. Phys.: Condens. Matter 10 L119 (1998). [3] K. Endo et al., J. Magn. Magn. Mater. 177-181 1437 

(1998). 

Electronic structures and magnetic properties of antiferromagnetic 

BaFe 2As 2 

Jae Kyung Chang, Ju Young Kim, Chang Hyun Yi and Joo Yull Rhee* 

Department of physics, Sungkyunkwan university, Korea 

In low dimensional metals the electrons can be organized into regular patterns, 

which is known to be the charge-density wave(CDW) or spin-density wave(SDW). 

The parent compound of iron-based superconductors, BaFe 2As 2, undergoes both 

structural and magnetic phase transitions. The crystal structure changes from tetragonal 

to orthorhombic, and the magnetic ground state changes from paramagnetic to 

antiferromagnetic at ~140 K and neutron scattering measurements show the magnetic 

moment of 0.87μB per Fe in antiferromagnetic state. SDW anomaly at 140 K, which 

is believed to be an important prerequisite for high-Tc superconductivity in ironbased 

superconductors, was also observed. We performed the electronic-structure 

calculation for the BaFe 2As 2 compound in various antiferromagnetic states, and the 

electronic structures and Fermi surfaces are carefully investigated. While there have 

been considerable debates as to whether the antiferromagnetism is due to the Fermisurface 

nesting or the second-neighbor superexchange, via comparing our results with 

experimental and hypothetical cases, we can deduce the correlation between the SDW 

and the Fermi-surface nesting. 

Development of magnetic order in the TbNi(Al,In) series and 

magnetocrystalline anisotropy in TbTX compounds 

Milan Klicpera 1 *, Pavel Javorsky 1 , Ines Puente Orench 2 , Eva Santava 3 and Stanislav 

Danis 1 

1 

Department of Condensed Matter Physics, Charles University in Prague, Faculty of 

Mathematics and Physics, Czech Republic 

2 

Institut Laue-Langevin, Grenoble, France 

3 

The Academy of Sciences of the Czech Republic, Czech Republic 

We present recent study of magnetocrystalline anisotropy in TbNi(Al,In) series, crystallizing in hexagonal 

ZrNiAl structure. The properties of this series were investigated by magnetic measurements, lowtemperature 

x-ray diffraction in magnetic field and mainly by powder neutron diffraction. Parent compounds 

of our series were previously studied. TbNiAl orders antiferromagnetically with propagation (1/2,0,1/2) and 

at lower temperatures undegoes another magnetic phase transition when one third of magnetic moments is 

reduced to almost zero. TbNiIn shows complex magnetic ordering with propagation vector (0,0,0) and other 

propagation (1/2,0,1/2) occurs at lower temperatures. Our data reveal suppression of the antiferromagnetic 

structure of TbNiAl with substitution of 10% Al by In. Instead, dominant ferromagnetic order appears, 

while the direction of Tb magnetic moments along the c-axis is retained. Additional weak antiferromagnetic 

components arranged within the basal plane and described by k=(1/2,0,1/2) appear at low temperatures. 

This antiferromagnetic component is presented in the whole rest of series. Dominant component described 

by (0,0,0) propagation then undergoes change from c-axis ferromagnetic order to a more complex basalplane 

structure around 40% of In. Anisotropy change in this series is related to strong change of the c/a ratio 

of lattice parameters. This behaviour can be generalized for other hexagonal Tb-based compounds. 


Poster Tuesday


QI02 


Magnetic properties of Ho 1-xLu xB 12 solid solutions 

Slavomir Gabani 1 , Emil Gazo 1 , Gabriel Pristas 1 , Marian Reiffers 1 , Iveta Takacova 1 , 

Natasha Shitsevalova 2 , Konrad Siemensmeyer 3 , Nickolay Sluchanko 4 and Karo l 

Flachbart l * 

1 Institute of Experimental Physics of Slovak Academy of Sciences, Kosice, Slovak 

2 Institute for Problems of Materials Sciences, NASU, Kiev, Ukraine 

3 Helmholtz Zentrum Berlin, Berlin, Germany 

4 General Physics Institute, RAS, Moscow, Russia 

Rare earth dodecaborides (REB 12) have attracted considerable attention in recent 

years, above all due to the wide variety of their physical properties. In our contribution 

we present the magnetic properties of the geometrically frustrated antiferromagnet 

HoB 12 (with ordering temperature T_N = 7.4 K) modified by substitution of magnetic 

Ho atoms through nonmagnetic Lu ones. In this case, in the so-called solid solution 

Ho 1-xLu xB 12, both chemical pressure (as Lu 3+ ions and Ho 3+ ions have different radii) 

and magnetic dilution take place with the increasing content of Lu that change the 

properties of the system. The received results show strong indication for the existence 

of a quantum critical point close to x = 0.9. This critical point separates the region of 

magnetic order (starting with HoB 12 for x = 0) and the nonmagnetic region (ending 

with superconducting LuB 12 for x = 1). The work was supported by the Slovak 

Scientific Agency VEGA (0148-10), the Slovak Research and Development Agency 

APVV, and by the Center of Excellence of the Slovak Academy of Sciences. 

QI03 

High-field magnetization of Tm2Fe17 and its deuteride 

A. V. Andreev 1 *, O. Isnard 2 , M. D. Kuz'min 3 , Y. Skourski 4 , D. I. Gorbunov 1 , J. 

Wosnitza 4 , N. V. Kudrevatykh 5 , A. Iwasa 6 , A. Kondo 6 , A. Matsuo 6 and K. Kindo 6 

1 

Institute of Physics ASCR, 18221 Prague, Czech Republic 

2 

Institut Neel CNRS and Universite Joseph Fourier, BP166X, Grenoble, France 

3 

IFW, 01171 Dresden, Germany 

4 

High Magnetic Field Laboratory, 01314 Dresden, Germany 

5 

Ural Federal University, 620083 Ekaterinburg, Russia 

6 

ISSP, Tokyo University, 277-8581 Kashiwa, Japan 

A magnetization study of a Tm 2Fe 17 single crystal and aligned powder of the deuteride 

Tm 2Fe 17D 3 has been carried out in steady (14 T) and pulsed (60 T) magnetic fields at 1.5- 

300 K. Tm 2Fe 17 is a ferrimagnet with T C=295 K and a spontaneous moment of 21 μ B/f.u. 

Due to competing magnetic anisotropy of the Tm and Fe sublattices, a spin-reorientation 

occurs at 70-100 K, from the easy-axis to the easy-plane type via a cone of easy axes. 

Two metamagnetic transitions, at 41 and 53.5 T, are observed at 2 K in fields applied 

along the c axis. At 60 T the magnetization reaches 43 μ B/f.u., i.e. the sublattices are not 

yet parallel (M Fe+M Tm= 49 μ B). In the basal plane a wide S-shape magnetization curve is 

observed. The high-field behavior of Tm 2Fe 17 is compared with that of two other easyaxis 

R 2T 17 compounds, Tm 2Co 17 and Er 2Co 17. Hydrogenation (deuteration) stabilizes easyplane 

anisotropy in Tm 2Fe 17D 3 over whole ferrimagnetic range (up to T C=465 K). Despite 

different types of magnetic anisotropy, the high-field behavior of the deuteride and the 

parent compound is qualitatively similar. The transitions along the c axis occur in the same 

fields, being less pronounced in the deuteride. 

QI04 

RKKY interaction and magnetic properties in (Y-Gd)Ni compounds 

Kazuo Yano 1 *, Katsuhiko Nishimura 2 , Eiji Kita 3 , Tsuyoshi Ohta 4 and Kiyoo Sato 5 

1 

College of Science and Technology, Nihon University, Japan 

2 

Graduate Scool of Science and Engineering for Research, University of Toyama, 

Japan 

3 

Applied Physics, University of Tsukuba, Japan 

4 

Quatum Desighn Japan, Japan 

5 

Faculty of Engineering, Yokohama National University, Japan 

CeNi is well known as one of the most famous heavy fermion compounds and shows 

a peculiar behavior as an enhanced Pauli-paramagnet. That is, both Ce and Ni seem to 

be non-magntetic in CeNi. On the other hand, GdNi, which has the same structure as 

that of CeNi, is a ferri-magnet and not only Gd but also Ni are magnetic. It follows that 

the result that Ni is non-magnetic in CeNi becomes not self-evident and the mechanism 

of disappearance of Ni magnetic moment is important and interesting problem. Based 

on such scenario, we have been investigating a (Ce-Gd)Ni compound system. One of 

the results obtained is a linear relationship in M(T) in Gd-poor content (Gd

QI08 

Giant magnetoresistance and field-induced phase transitions in Tb 7Rh 3 

single crystal 

Takanori Tsutaoka 1 *, Koji Shimomura 1 , Nikolay V. Baranov 2 , Alexey V. Proshkin 2 , 

Evgeny G. Gerasimov 3 and Pavel B. Terentev 3 

1 Graduate School of Education, Hiroshima University, Japan 

2 Institute of Natural Sciences, Ural Federal University, Russia 

3 Institute of Metal Physics, Ural Branch of RAS, Russia 

The rare earth intermetallic compound Tb 7Rh 3 crystallizes in the Th 7Fe3 type hexagonal 

structure with the space group P63mc in which Tb occupies three non-equivalent sites. 

Tb 7Rh 3 enters an antiferromagnetic (AF) state below TN = 91 K and shows further magnetic 

transformations with decreasing temperature below ~ 73 K [1]. Unusual negative temperature 

coefficient of the resistivity in a wide temperature range above TN [1] and the large 

magnetoresistance even in paramagnetic state [2] were observed for this compound. In this 

study, we have performed high field magnetization (up to 350 kOe) and magnetoresistance 

(up to 120 kOe) measurements on a Tb 7Rh 3 single crystal. The metamagnetic transition along 

the b-axis is observed to be accompanied by the giant magnetoresistance effect (~ 65 %) in the 

field interval (70 -110) kOe. The magnetization measurements along the c-axis have revealed 

multiple phase transitions at fields above 200 kOe. The magnetization curves measured in 

the paramagnetic state along the c-axis show an inflection point up to 140 K, which may be 

indicative of the persistence of antiferromagnetic short-range magnetic order in the c-plane. 

[1] Y. Nakamori et al. Physica B, 304 (2001) 1. [2] K. Sengupta et al. Solid State Comm., 39 (2006) 

351 

QI09 

Magnetic properties of a GdFe 5Al 7 single crystal 

D. I. Gorbunov 1 *, A. V. Andreev 1 and M. D. Kuz'min 2 

1 Institute of Physics ASCR, 18221 Prague, Czech Republic 

2 IFW, 01171 Dresden, Germany 

A magnetization study of a GdFe 5Al 7 single crystal has been carried out in static 

magnetic fields up to 14 T at temperatures between 2 and 300 K. The compound is 

found to order ferrimagnetically at T C = 266 K. The spontaneous magnetic moment 

is 0.56 μ B at 2 K. There is no compensation point in GdFe 5Al 7, as distinct from 

isomorphic compounds DyFe 5Al 7 and HoFe 5Al 7. GdFe 5Al 7 is endowed with an 

appreciable magnetic anisotropy, the 4-fold axis being a hard magnetization direction. 

The easy direction is [110] and the anisotropy within the basal plane is also rather 

strong. The latter is quite remarkable for a system devoid of significant orbital 

moments. The possible cause of the in-plane anisotropy in GdFe 5Al 7 could be the 

unusually large crystal field parameter B 44, as observed in other compounds with the 

ThMn 12-type structure, e.g., in DyFe 11Ti. The crystal field effect could be mediated 

by a small admixture of the 4f 8 configuration to the ground state 4f 7 . The exchange 

field on the Gd sublattice is determined from the high-field slope of the basal-plane 

magnetization curves to equal 62 T. 

QI10 

Study of multipole ordering in CePd3S4 by resonant X-ray diffraction 

with full polarization analysis 

Sinji Michimura 1 *, Toshiya Inami 1 , Toru Otsubo 2 , Takeshi Matsumura 2 , Hiroshi 

Tanida 2 , Masafumi Sera 2 , Eiichi Matsuoka 3 , Masanori Watahiki 4 , Katsumi Tanigaki 4 

and Hideya Onodera4 

1 

Condensed Matter Science Division, Japan Atomic Energy Agency, Japan 

2 

AdSM, Hiroshima University, Japan 

3 


4 


In rare-earth palladium bronzes RPd 3S 4 (R = La-Yb) compounds with a cubic structure, it is expected that 

the multipole interactions dominate the low temperature properties because the degeneracy of the orbital 

degree of freedom remains in the crystalline electric field ground states of R 3+ in RPd 3S 4 except for R = 

Tm.[1] CePd 3S 4 orders ferromagnetically below the transition temperature TC = 6.3 K.[2] Recently we 

revealed that the O20-type quadrupole moments order below TC, and infered that the magnetic structure 

is a ferrimagnetic structure by resonant x-ray diffraction (RXD) experiments.[3] Since the symmetry of the 

magnetic and O20-type quadrupole moments differs from each other, simultaneous order of them below 

TC suggests the involvement of the octupole interaction. We performed full polarization analysis of RXD 

experiments in magnetic fields to study the contribution of an octupole interaction. The experiments were 

performed at the Ce-L 3 absorption edge using a single crystal at BL22XU in SPring-8. In our presentation, 

we will discuss the contribution of multipole interactions for the low temperature properties in detail. 

[1] K. abe et al.: Phys. Rev. Lett. 76 (1999) 5366. [2] E. Matsuoka et al.: J. Phys. Soc. Jpn. 77 (2008) 

114706. [3] S. Michimura et al., submitted to J. Phys. Soc. Jpn. 

QI11 

QI12 

QI13 


Effect of temperature and magnetic field history on magnetization 

behavior of NdVO 3 polycrystalline 

Zhengcai Xia* 

wuhan national high magnetic field center, huazhong university of science and 

technology, China 

The magnetic properties of NdVO 3 polycrystalline have been studied in the 

temperature range from 300 to 1.8K and in magnetic fields up to 16 T. It is found 

that in an applied field less than 1 T remarkable magnetization reversals occurred 

in field cooling mode: a diamagnetic behavior was observed below a compensation 

temperature Tcomp. Most interestingly, the diamagnetic behavior was dependent to 

both the temperature and applied magnetic field, where the temperature window is 50- 

100K, and magnetic field below 1T. Beyond the temperature window and above the 

magnetic field, the diamagnetic behavior disappeared. That is the magnetization always 

switches to the opposite direction if the sample is cooled through the temperature 

window in a field less than 1 T. However, the temperature dependence of the resistance 

has an almost independent to the applied magnetic field in the range from 0 to 16T. A 

possible mechanismbased on the competition of the single-ion magnetic anisotropy 

and the antisymmetric Dzyaloshinsky-Moriya interaction accompanied by a change of 

orbital ordering is discussed. 

Phase diagram and transport properties of Y1-xNdxCo2 pseudo-binary 

alloys 

Alexander T Burkov 1 , Masataka Takeda 2 , Ai Nakamura 2 , Yoshinao Takaesu 2 , 

Kiyoharu Uchima 3 , Masato Hedo 2 , Takao Nakama 2 *, Katsuma Yagasaki 2 and Yoshiya 

Uwatoko 4 

1 

A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, Russia 

2 

Department of Physics and Earth Sciences, Faculty of Science, University of the 

Ryukyus, Japan 

3 


4 


Electrical resistivity ρ and thermopower S of pseudo-binary Y 1-xNd xCo 2 alloys have been measured at 

temperatures from 2 K to 300 K, under pressures up to 3.5 GPa. NdCo 2 is a ferromagnet with Curie 

temperature TC of 99 K. In ferromagnetic phase it undergoes 4f spin-reorientation transition at TR = 40 K. 

At this transition the easy direction of 4f magnetization is changed from [100] above TR to [110] below 

TR. The system phase diagram TC(x,P) and TR(x,P) is inferred from the temperature dependencies of the 

electrical resistivity and thermopower. The Curie temperature of the alloys, TC decreases with decreasing 

Nd concentration x and vanishes around xc=0.3. Above xc the Curie temperature decreases with pressure. 

The spin-reorientation temperature is weakly dependent on composition and on pressure until it merges 

with TC. There is a large region of the phase diagram, partly overlapping with the ferromagnetic phase, 

where cobalt 3d electron system is non-uniformly magnetized due to spatial fluctuations of the 4f-3d 

exchange field, related to random distribution of Nd 4f magnetic moments over R-sublattice. In this region, 

spanning the range 0 < x < xm, large static 3d magnetic fluctuations govern the electronic transport. 

Effect of partial magnetic order on resistivity and thermopower of 

Ho(Co1-xAlx) 2 alloys 

Takao Nakama 1 *, Chojun Zukeran 1 , Ai Nakamura 1 , Atsushi Teruya 1 , Sentaro 

Hirakawa 1 , Shintaro Watanabe 1 , Masataka Takeda 1 , Yoshinao Takaesu 1 , Kiyoharu 

Uchima 2 , Masato Hedo 1 , Katsuma Yagasaki 1 and Alexander T Burkov 3 

1 

Department of Physics and Earth Sciences, Faculty of Science, University of the 

Ryukyus, Japan 

2 


3 

A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, Russia 

The electrical resistivity ρ and thermopower S of Ho(Co 1-xAl x) 2 alloys (x = 0, 0.15 and 

0.2) were measured from 2 K to 300 K in magnetic fields up to 10 T and under pressures 

up to 3 GPa. While ρ(T) and S(T) of the pure HoCo 2 reveal abrupt changes at the 

magnetic ordering temperature TC, indicating the first order transition, the temperature 

variation of both properties across the ordering temperature in Ho(Co 1-xAl x) 2 alloys 

clearly show that the type of the magnetic transition changes under substitution of Al for 

Co from the first order to the second order. ρ(T ) of the Al substituted samples (x = 0.15 

and 0.2) has a very unusual variation below TC. Usually, the resistivity of an itinerant 

ferromagnet decreases below TC with decreasing temperature at higher rate than above 

TC, its temperature derivative having positive “lambda” anomaly at the ordering point. 

In contrast, ρ(T ) of Ho(Co 1-xAl x) 2 alloys (x=0.15 and x=0.2) increases below TC. 

Moreover, the magnetoresistance of these alloys is positive around TC, this is also in a 

sharp contrast to usually observed negative magnetoresistance. 


Poster Tuesday


QI14 


Breakdown of Hund’s third rule for intrinsic magnetic moments 

Julia Herrero-albillos 1 *, Fernando Bartolome 2 , Luis Miguel Garcia 2 and A. T. Young 3 

1 

CUD, Centro Universitario de la Defensa, Ctra. de Huesca s/n, E-50090 Zaragoza, 

Spain, Spain 

2 

ICMA, ICMA and Dpto. de Fisica de la Mat. Cond. CSIC - Universidad de 

Zaragoza, Pedro Cerbuna 12, Spain, Spain 

3 

Advanced Light Source, Lawrence Berkeley National Laboratory, University of 

California Berkeley, CA, USA 

Hund’s rules were originally developed in an atomistic picture, and it is therefore 

surprising that they also hold, almost universally, for molecules and solids. Here we 

report the first experimental example of a breakdown of Hund’s third rule in an intrinsic 

magnetic moment: the Co 3d moment of the unorthodox ferrimagnet ErCo 2. The 

application of magneto-optical sum rules to X-ray magnetic circular dichroic spectra 

allows for the determination of the Co orbital and spin magnetic moments both in the 

ferrimagnetic and paramagnetic phases of ErCo 2. In agreement with the predictions 

of Hund’s third rule, Co orbital and spin moments are parallel throughout the overall 

temperature range, except in a narrow temperature window within the paramagnetic 

phase, in which they are overall coupled antiparallel. A qualitative consideration of 

the balance between the interatomic and intra-atomic interactions acting on the cobalt 

atoms explains the phenomenon. This situation also leads to the observation of other 

exotic forms of magnetism in solids, such as a “pure” spin or a “pure” orbital moment 

on the same compound at selected temperature and fields. 

QI15 

Magnetic properties of Y substituted TbB4 Boyoun Kang 1 , Sungsu Lee 1 , Juyoung Kim 2 and B. K. Cho 1 * 

1 

School of Materials Science & Engineering, Gwangju Institute of Science and 

Technology, Korea 

2 

Advanced matallic materials research department, Research Institute of Industrial 

Science & Technology, Korea 

We synthesized the single crystals of Tb 1-xY xB 4 (x=0.0, 0.1, 0.2, 0.3, 0.35, 0.4, 0.5, 

and 0.6)using metallic flux method. The lattice parameters of these crystals are 

confirmed by powder x-ray diffraction using Fullprof program. The lattice parameters 

are decreased with increasing substituted Y ratio, according to Vegard’s law. The 

measurements of temperature-dependent magnetization M(T) is carried out for the 

single crystals of Tb 1-xY xB 4 (x=0.0, 0.1, 0.2, 0.3, 0.35, 0.4, 0.5, and 0.6) in 1 Tesla. 

The compounds reveal antiferromagnetic ordering and its Neel temperatures are 

decreased with increasing Y ratio. We confirm the spin direction of antiferromagnetic 

contribution in Tb 0.65Y 0.35B 4 using single crystal neutron scattering. The direction of Tb 

spin magnetic moment is tilted from a axis. 

QI16 

High pressure effects on antiferroquadrupolar orders in RB 2C 2 (R = 

Dy and Ho) 

Hiroki Yamauchi 1 *, Toyotaka Osakabe 1 , Masashi Kosaka 2 , Eiichi Matsuoka 3 and 

Hideya Onodera 4 

1 Quantum Beam Science Directorate, Japan Atomic Energy Agency, Japan 

2 Graduate School of Science and Engineering, Saitama University, Japan 


4 Department of Physics, Graduate School of Science, Tohoku University, Japan 

Single-crystal neutron diffraction experiments under 10 GPa class pressure were performed 

on tetragonal DyB 2C 2 and HoB 2C 2 compounds showing antiferroquadrupolar (AFQ) and 

antiferromagnetic (AFM) orders. Both magnetic structures in the ground state phases are 

basically same and described mainly by the propagation vectors k1 = (1, 0, 0) and k2 = (0, 1, 

1/2) for an AFM alignment in the c-plane and an orthogonal arrangement along the c-axis. This 

characteristic zigzag structure is attributed to the competitive coexistence of the underlying 

AFQ order with the AFM order. Our purpose is to investigate pressure effects on the AFQ and 

AFM orders through the alteration of the magnetic structures with k1 and k2. The high pressure 

experiments revealed that applying pressure enhanced the AFM interactions and simultaneously 

suppressed the AFQ orders in the both compounds. In addition, we found that applying pressure 

shranks the crystal volumes more greatly in the direction of the c-axis even under hydrostatic 

pressure. Therefore, we presume that the volume shrinkage by applying pressure constrains the 

buckling accompanied by the AFQ orders, which means a local atomic displacement of (B-C) 

layers along the c-axis, and leads to the suppression of the AFQ orders in the both compounds. 


QI17 

Antiferromagnetism of TbPd 2Ge 2 Single Crystals 

Takahiro Hasegawa 1 *, Fujiwara Tetsuya 1 , Matsubayashi Kazuyuki 2 , Uwatoko 

Yoshiya 2 and Shigeoka Toru 1 

1 Grad. Sch. Sci. and Eng. Yamagnchi Univ., Japan 

2 ISSP. Univ. Tokyo., Japan 

The compound TbPd 2Ge 2, having the tetragonal ThCr 2Si 2-type crystal structure, 

exhibits an antiferromagnetic order below TN=4 K [1]. The details are not clear. In 

order to clarify magnetic behavior, we have grown TbPd 2Ge 2 single crystals, and 

carried out magnetic and specific heat measurements using the single crystals. The 

magnetic susceptibility shows an anomaly at 13 K in susceptibility vs. T curves, 

indicating an antiferromagnetic order. The appearance of anomaly at 13K is confirmed 

in specific heat. This transition temperature is fairly higher than one reported previously 

[1]. The easy magnetization direction is the [100] direction in the basal plane within 

this experimental magnetic field up to 7 T. Three metamagnetic transitions appear in 

the process at low temperatures. In the [110] magnetization process, two metamagnetic 

transitions are observed. In magnetization curves along the all directions, downward 

curvatures can be seen, suggesting a precursor of further transition. From these results, 

the magnetic behavior of this compound is discussed in detail. 

[1] A.Szytula et al., Solid State Commun.66 (1988) 309. 

QI18 

Multi-step metamagnetic processes in PrPd 2Si 2 single crystal 

Toru Shigeoka 1 *, Tetsuya Fujiwara 1 , Kazuyuki Matsubayashi 2 , Yoshiya Uwatoko 2 , 

Shoji Kimura 3 and Kazuo Watanabe 3 

1 Yamaguchi University, Japan 

2 ISSP., University of Tokyo, Japan 

3 IMR., Tohoku University, Japan 

Magnetic studies have been performed in detail on a PrPr 2Si 2 single crystal which is 

crystallized in the tetragonal ThCr 2Si 2-type structure. The temperature dependence 

of magnetic susceptibility indicate the compound orders antiferromagnetically 

below TN=3.0 K. The transition has been confirmed by specific heat. Magnetization 

measurements up to 18 T have been performed and obtained following results. The easy 

magnetization direction is the [100] direction in the basal plane. In the magnetization 

process, four metamagnetic transitions appear; it is a four-step metamagnetic one. The 

[110] magnetization process is a three-step one. A strong magnetic anisotropy between 

the [100] and [110] directions is observed within the basal plane in high magnetic 

fields. Along the hard magnetization direction of the c-axis, a metamagnetic transition 

appears. A magnetic anisotropy between the [100] and [001] directions is also strong. 

These behaviors are discussed from an analysis of crystal field effects. 

QI19 

Anisotropic properties of Tb 2Pd 2In single crystal 

Silvie Maskova 1 , Ladislav Havela 1 , Olexander Kolomiets 2 , Alexander V. Andreev 3 and 

Pavel Svoboda 1 * 

1 Department of Condensed Matter Physics, Charles University, Czech Republic 

2 Department of Physics, Lviv Polytechnic National University, Ukraine 

3 Institute of Physics, ASCR, Czech Republic 

Tb 2Pd 2In (tetragonal Mo 2FeB 2 structure type) was reported to be an antiferromagnet 

with the Neel temperature TN = 32 K and metamagnetic transition at μ0Hc = 4 T [1]. 

On the contrary, our magnetization measurements on polycrystalline sample indicate 

that the magnetization curve of Tb 2Pd 2In has 4 metamagnetic features in the field range 

to 14 T. We have succeeded to prepare singe-crystalline sample of Tb 2Pd 2In using 

Czochralski method. The magnetic susceptibility measured on single-crystal in various 

crystallographic directions shows that magnetic properties of Tb 2Pd 2In are highly 

anisotropic. c-axis was found to be an easy magnetization direction. The magnetization 

curve along the c-direction at T = 2 K shows two metamagnetic transitions (μ0Hc 

= 5 and 8 T). The magnetization is completely saturated at 14 T (Ms = 19.1 μB/ 

f.u.). We have also observed another metamagnetic transition along the a-direction. 

The magnetization in the a-direction does not show any tendency to saturation in the 

highest available fields. 

[1] M. Giovannini et al., J. Alloys Compd. 280, 26 (1998).

QJ01 

Successive magnetic transitions of PrRh 2Ge 2 single crystal 

Okawara Yuu 1 *, Cui Jingwei 1 , Fujiwara Tetsuya 1 , Matsubayashi Kazuyuki 2 , Uwatoko 

Yoshiya 2 , Kimura Shoji 3 , Watanabe Kazuo 3 and Shigeoka Toru 1 

1 Grad. Sch. Sci. and Eng. Yamagnchi Univ., Japan 

2 ISSP. Univ. Tokyo., Japan 

3 IMR. Tohoku Univ., Japan 

The ternary compound PrRh 2Ge 2, having the tetragonal ThCr 2Si 2-type crystal structure, 

shows an interesting magnetic behavior; it orders antiferromagnetically below TN=45 

K and exhibits an additional magnetic transition at Tt=30 K [1]. The details have been, 

however, unknown yet. In order to elucidate its magnetic behavior, measurements of 

magnetization and specific heat have been performed on a PrRh 2Ge 2 single crystal. A much 

large magnetic anisotropy with the easy magnetization direction of c-axis is observed. 

Four anomalies appear in the temperature dependence of magnetic susceptibility along the 

c-axis; a cusp at TN=52 K, a high peak at T3=38 K, a shoulder at T2=33 K and a small 

peak at T1=4 K are observed. Specific heat also shows four anomalies at corresponding 

temperatures where magnetic anomalies appear, confirming an occurrence of successive 

magnetic transitions. A clear two-step metamagnetic process appears along the easy 

magnetization direction of the c-axis at low temperatures. The magnetization in the first 

step is almost flat and is corresponding to (1/5) Ms, indicating this field-induce phase has a 

long period magnetic structure. This behavior is discussed as one of characteristic features 

for Ising-like system with competing exchange interactions. 

[1] A. Szytula et al., Intermetallics 18 (2010) 1766. 

QJ02 

Phase diagram of the magnetically frustrated system SmPd2Al3 studied 

by neutron diffraction 

Jiri Pospisil 1 *, Gwilherm Nenert 2 , Hideaki Kitazawa 3 , Martin Divis 1 , Jan Prokleska 1 

and Vladimir Sechovsky 1 

1 

DCMP, Charles University, Ke Karlovu 5, 121 16, Prague, Czech Republic 

2 

Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, F-38042 Grenoble Cedex 9, 

France 

3 

National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan 

SmPd 2Al 3 represents a distinctive example of Sm magnetism exhibiting a complex magnetic behavior [1]. 

The complexity of magnetism is caused by specific features of the Sm 3+ ion, namely by nearness of the 

ground-state multiplet J = 5/2 and the first excited multiplet J = 7/2 in conjunction with strong crystal field. We 

have established a magnetic phase diagram based on magnetization data. Detailed information regarding the 

magnetic structure of each magnetic phase was lacking and neutron diffraction was highly desirable. To reduce 

the neutron absorption by the Sm we have performed an experiment at the ILL Grenoble D9 diffractometer with 

the short wavelength neutrons which are much less absorbed by the natural Sm. The four successive magnetic 

phases have been detected within the neutron diffraction experiment providing the values of the critical 

temperatures 3.5, 4, 4.5 and 12.4. Despite the still strong Sm neutron absorption and the low effective magnetic 

moment we have determined the magnetic k-vector (1/3 1/3 0) of the phase existing in the temperature interval 

12.4-4.5 K which classifies the SmPd 2Al 3 to the unique group of magnetically frustrated systems. Discussion 

will be drawn in the context of recent theoretical approaches to geometrically frustrated magnetic systems. 

[1] J. Pospisil, M. Kratochvilova, J. Prokleska, M. Divis, V. Sechovsky; Phys. Rev. B 81, 024413 

(2010) 

QJ03 

Interplay of rare-earth and iron sublattices in NdFeAsO 

Gwendolyne Pascua 1 , Hubertus Luetkens 1 , Yurii G. Pashkevich 2 , Hemke Maeter 3 and 

Hans-henning Klauss 3 

1 

Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen 

PSI, Switzerland 

2 

A.A. Galkin Donetsk Phystek,, NASU, 83114 Donetsk,, Ukraine 

3 

Institut fur Festkorperphysik,, TU Dresden, DE-01069 Dresden,, Germany 

We report zero-field (ZF) muon spin relaxation (μSR) measurements on NdFeAsO 

polycrystalline samples. We investigate the interaction of the Fe magnetic sublattice with 

the RE (rare-earth) paramagnetic moment in the nonsuperconducting magnetically ordered 

Nd oxypnictide by a detailed analysis of the hyperfine fields at the muon site. At high 

temperatures, the fluctuations of the Nd moments are evident from the observed exponential 

depolarization of the μSR signal. Microscopic evidence of static commensurate magnetic 

order of Fe moments is revealed by μSR at temperatures below TΝ(Fe) = 136K. Drastic 

slowing down of RE moment fluctuations is observed only below TΝ(RE) = 2K. In the 

intermediate temperature range, a Schottky-like polarization of the Nd magnetic sublattice by 

the ordered Fe system is observed. In the Fe system, a transition between a high- and a low- 

temperature magnetic structures is proposed on the basis of a detailed symmetry analysis and 

magnetic dipole-field calculations at the muon site. The observed behavior resembles the one 

of the spin reorientation in the structurally-related Nd 2CuO 4. 

[1] H. Maeter, H. Luetkens, Y. Pashkevich, et.al. Phys. Rev. B. 80 094524 (2009). [2] W. Tian, et.al. 

Phys. Rev. B. 82, 060514 (2010). [3] Y. Qiu, et.al. Phys. Rev. Lett. 101, 257002 (2008). 

QJ04 

QJ05 

QJ06 


Magnetic properties of C15 laves phase compound SmRu 2 

Yusuke Amakai*, Mototsugu Sato, Naoki Momono, Hideaki Takano and Shigeyuki 

Murayama 

Graduate School of Engineering, Muroran Institute of Technology, Japan 

We report the magnetic properties of polycrystalline C15 laves phase rare-earth 

compound SmRu 2. The sample of SmRu 2 was made by an arc-melt method and was 

annealed at 500 °C in vacuumed quartz tube for 50 hours. The susceptibility χ of 

SmRu 2 follows a typical Curie-Weiss law above 80 K. The effective magnetic moment 

peff is 1.39 μB/Sm-atom, and the Weiss temperature θ is a positive value of 42 K. The 

low-temperature χ for T < 70 K increases rapidly with decreasing temperature. In the 

resistivity ρ and the specific heat Cp, we found a small anomaly and a jump at about 

55 K. Furthermore, we observed a hysteresis in the magnetic field dependence of 

magnetization at 2 K. These experimental results suggest that C15 laves phase SmRu 2 

is ferromagnetic material on Tc ~ 55 K. Detailed discussion will be presented at the 

conference. 

Pressure effect on the electrical resistivity of a ferromagnetic clathrate 

Eu8Ga16Ge30 T Iizuka 1 , K Umeo 2 *, M A Avila 3 and T Takabatake 1 

1 

AdSM, Hiroshima Univ., Kagamiyama 1-3-1, Higashi-Hiroshima 739-8530, Japan 

2 

N-BARD, Hiroshima Univ., Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, 

Japan 

+ Federal University of ABC, Santo Andre, SP, 09210-170, Brazil 

Eu 8Ga 16Ge 30 is a unique intermetallic clathrate in which the guest sites are fully 

occupied by a rare-earth element. The Eu 2+ ions in the tetrakaidecahedral cages in the 

type-I structure are rattling among off-center positions [1]. This compound exhibits a 

ferromagnetic transition at Tc=36K. Both the electrical resistivity ρ and the temperature 

deviative of magnetization exhibit peaks at Tc and T*. Upon applying pressure of 

6GPa at 290K, the off-center rattling state of Eu ions changes to the on-centered state. 

Furthermore, at Ps=14GPa, a structural transition occurs with the volume reduction 

of about 4% [2]. In order to examine the pressure dependence of Tc and T*, we have 

measured the temperature dependence of ρ under various pressures up to 15GPa, by 

using a Bridgman anvil cell made of sintered diamond. With increasing pressure, Tc 

shifts to higher temperatures. Broading of the peak at T* for P≥4GPa is attributed to 

the change from the off-center to on-center state. At 290K, ρ(P) jumps at 13GPa, which 

must be the manifestation of the structural transition. 

[1] B. C. Sales, et al., Phys. Rev. B 63, 245113 (2001). [2] T. Kume et al., unpublished. 

Magnetic transitions under pressure in GdCo 2B 2 

Guanghui Hu 1 *, Izuru Umehara 1 , Lingwei Li 2 and Katsuhiko Nishimura 3 

1 Department of Physics, Yokohama National University, Japan 

2 Institute of Materials Physics, Hangzhou Dianzi University, China 

3 Graduate School of Science and Engineering, University of Toyama, Japan 

The pressure effect on magnetic transitions of GdCo 2B 2 compound was studied by dc susceptibility and ac 

heat capacity in the temperature range 2 K ~ 300 K. The temperature dependence of dc susceptibility for 

GdCo 2B 2 under various pressure in 0.1 T magnetic field show two information. First, the Antiferromagnetic 

transition temperature TN decrease with pressure increasing from 12.5 K in 0GPa decrease to 6.3 K in 1.07 

GPa and disappeared near to 1.30 GPa with a slope of dTN/dP about -5.8 K/Gpa. Second, ferromagnetic 

transition TC increases alightly with pressure increasing from 20.4 K in 0 GPa to 22.1 in 1.27 GPa with 

a slope of dTC/dP about 1.5 K/Gpa. They were also found in ac heat capacity measurements. It can be 

understand that there is a strong interaction in the ferromagnetic state and a very weak interaction in 

antiferromagnetic state which can easily be destroyed by pressure and magnetic field. The transitions 

are proved to be the second-order transition. In addition, a transition temperature TM which comes from 

domains of ferromagnetism in heat capacity measurements was found increase from 17.5 K under 0 GPa 

to 22.0 K under 2.36 GPa with a ratio dTM/dP about 2.2 K/GPa. 

[1] L. Li, K. Nishimura, and H. Yamane, Appl. Phys. Lett. 94 (2009) 102509 [2] L. Li, D. Huo, Z. 

Qian, and K. Nishimura, J. Phys.: Conf. Ser. 263 (2011) 012017 [3] I. Felner, Sol. Sta. Comm. 52 

(1984) 191-195 [4] V. K. Pecharsky, and K. A. Gschneidner, Jr., Int. J. Refrig, 29 (2006) 1239 [5] 

I. Umehara, F. Tomioka, A. Tsuboi, T. Ono, M. Hedo, Y. Uwatoko, J. Magn. Magn. Mater. 272-276 

(2004) 2301-2302. 


Poster Tuesday


QJ07 


New ferromagnetic compounds with noncentrosymmetric crystal 

structures 

Yoshihiko Inada 1 *, Guizhi Bao 2 and Akiko Ono 1 

1 Graduate School of Education, Okayama University, Japan 


Recently, physical properties in noncentrosymmetric crystal structures have attracted 

considerable attentions. The broken inversion symmetry in the crystal causes finite 

antisymmetric spin orbit coupling (ASOC). A spin-polarized electrons that originates 

from the ASOC effect is formed even for nonmagnetic materials. Generally, the 

electronic states of opposite spin orientation are considered to be degenerate in 

nonmagnetic materials due to the presence of both time-reversal and space-inversion 

symmetries. However, this degeneracy will be solved by the ASOC in broken spaceinversion 

symmetries with noncentrosymmetric crystal structures. A pair of split bands 

is produced in the k-space. Ferromagnetic compounds with noncentrosymmetric 

crystal structures are interesting materials, because the time-reversal symmetries 

also broken. We discovered new ferromagnetic compouds, Pr 4Bi 3 and Nd 4Bi 3, with 

noncentrosymmetric crystal structures. They are crystalized in anti-Th 3P 4 structure 

(space group I-43d), which has no inversion center. Curie temperature T_C are 48K 

and 94K, respectively. Large ASOC is expected caused by heavy material of Bi. We 

will report further results in detail. 

QJ08 

Singlet-triplet crossover in the two-dimensional dimer spin system 

YbAl 3C 3 

Shunichiro Kittaka 1 *, Tomoyoshi Sugiyama 1 , Yasuyuki Shimura 1 , Toshiro 

Sakakibara 1 , Saori Matsuda 2 and Akira Ochiai 2 



YbAl 3C 3 has the hexagonal ScAl 3C 3 type structure in which magnetic Yb 3+ ions form a 

two-dimensional triangular lattice. At 80 K, it exhibits a structural phase transition to an 

orthorhombic structure with a slight displacement of the Yb atoms [1]. Interestingly, a 

dimer ground state with the singlet-triplet energy gap of about 15 K has been suggested 

from the magnetic susceptibility and the specific heat at low temperatures [2]. Indeed, a 

direct observation of the singlet-triplet excitations has been reported from the inelastic 

neutron experiments [3]. To investigate the variation of the ground states in magnetic 

fields, we measured magnetization of a single crystal of YbAl 3C 3 down to 0.07 K and 

in fields up to 14.5 T. At low temperatures below 0.8 K, several magnetization steps 

were clearly observed for H||c in 6 T < μ0H < 9 T, whereas only two transitions were 

observed at 4.7 and 6.6 T for H||ab. At fields above 9 T, the magnetization becomes 

almost saturated for both H||c and H||ab. Our results indicate that the singlet-triplet 

crossover occurs in a relatively narrow field range, suggesting a rather weak interdimer 

interaction in spite of the nearly triangular lattice of Yb ions. 

[1] T. Matsumura et al., J. Phys. Soc. Jpn. 77, 103601 (2008). [2] A. Ochiai et al., J. Phys. Soc. Jpn. 

76, 123703 (2007). [3] Y. Kato et al., J. Phys. Soc. Jpn. 77, 053701 (2008). 

QJ09 

Magnetic structure transition in PrPd 3 

Hiroyuki S. Suzuki 1 *, Noriki Terada 1 , Akiko Kikkawa 1 , Koji Kaneko 2 and Naoto 

Metoki 2 


2 Japan Atomic Energy Agency, Japan 

A complex magnetic phase diagram of PrPd 3 with AuCu 3-type structure was reported 

[1]. The specific heat shows double peaks at TN = 0. 88 K and 0.77 K, which are 

relatively low compared with the Curie-Weiss temperature Θp ~ 17 K. The temperature 

of the peak at higher temperature is increased but another decreased with the magnetic 

field. A large tail above TN in the specific heat is also observed. Considering no 

geometric frustrations in the simple cubic structure of the Pr site, these behavior suggest 

a competition of inter-site interactions. The magnetic field dependence of the peak at 

higher temperature, which is typical in the quadrupole ordering system, also suggests 

an importance of the multipole effect arising from the crystalline electric field ground 

state. We have investigated the multipole effect using the single crystal by specific heat, 

magnetic susceptibility, ultra-sonic and also neutron scattering measurements. In this 

report, we focus on the magnetic structure and its transition. We have found first the 

1st transition of the magnetic phase at 0.5 K. The propagation vector observed in the 

neutron scattering is changed from the incommensurate to commensurate one. We will 

discuss the complex magnetic phase based of the multipole effect. 

[1] S. Zhang, et al., Journal of Physics : <strong>Conference</strong> Series, 15 (2009) 042074 


QJ10 

Competition between magnetic ordering and random spin freezing in 

Dy 2PtSi 3 

D. X. Li 1 *, T. Yamamura 1 , S. Nimori 2 and T. Shikama 1 


2 Tsukuba Magnet Laboratory, National Research Institute for Metals, Japan 

We have been paying special attention to a new family of the ternary intermetallic compounds 

R 2PtSi 3. The spin-glass or cluster-glass-like effect can be observed in some R 2PtSi 3 compounds 

with heavy rare earth element, which have been confirmed to crystallize in the ordered hexagonal 

structure [1]. The mechanisms of the anomalous magnetic behaviors are very interesting in 

physics. Recently, we prepared a polycrystalline Dy 2PtSi 3 sample and systematically measured 

its magnetic properties including ac susceptibility (Χac), FC and ZFC magnetization, magnetic 

relaxation, electrical resistivity and specific heat. The most important observation is the evident 

peak in Χac(T) curve near Tc~6 K, which shifts to high temperature with increasing frequency 

suggesting the presence of random spin freezing effect. The observed long-time magnetic 

relaxation and the low temperature irreversible magnetism give further evidence for this 

conclusion. However, specific heat measurement shows an evident peak at Tc and the electrical 

resistivity drops rapidly as decreasing the temperature just below Tc. In this sense, the long-range 

magnetic exchange interactions have also important influence on the magnetic behavior. Thus it 

seems to be appropriate to classify the Dy 2PtSi 3 sample as a large magnetic cluster system with 

competition between magnetic ordering and random spin freezing. 

[1] D. X. Li , S. Nimori, Y. Homma and Y. Shiokawa, J. Phys. Soc. Jpn., 71 (2002) Suppl. 211. 

QJ11 

Dilatometric investigations on the semimetallic ferromagnet EuB6 Rudra Sekhar Manna 1 , Frank Schnelle 1 , Mariano De Souza 1 , Michael Lang 1 , Pintu 

Das 1 , Adham Amyan 1 , Jens Mueller 1 , Stephan Von Molnar 2 , Peng Xiong 2 and Zachary 

Fisk 3 

1 


(M), Germany 

2 

Department of Physics, Florida State University, Tallahassee, Florida 32306, USA 

3 

Department of Physics, University of California, Irvine, California 92697, USA 

EuB 6 is a semimetallic correlated electron system, which exhibits a complex 

sequence of electronic and magnetic phase transitions at ~ 15.5 K (Tc1) and 12.5 K 

(Tc2). The material also shows a colossal magnetoresistance effect which is largest 

at Tc1. A percolative transition of magnetic polarons, i.e., clusters of ordered Eu 2+ 

moments polarized by the spins of localized charge carriers (holes), is involved in the 

paramagnetic to ferromagnetic transition. Thermal expansion and magnetostriction 

measurements have been performed on this material to explore to which extent lattice 

degrees of freedom are involved in these phase transitions. We find two corresponding 

anomalies in the thermal expansion, the one occurring at Tc2 being much larger than 

that at Tc1. By applying a small magnetic field of less than 50 mT, the anomaly at 

Tc1 is fully suppressed, while the lower-temperature anomaly at Tc2 shifts to higher 

temperature as the field is increased and finally fades out at a field B > 5 T. These 

measurements are complemented by magnetostriction measurements for a set of 

temperatures from below Tc2 to above Tc1, highlighting the extraordinarily large 

magnetoelastic effects in this material. 

QJ12 

The magnetic anisotropy and magnetostriction of RAl 2 (R= rare earth) 

compounds 

Masashi Ohashi, Yusuke Araki and Kazuma Sawami 

Kanazawa University, Japan 

The RAl 2 (R : rare earth element) intermetallic compounds crystallize in the MgCu 2 

cubic Laves phase structure. In most of these compounds the R ions are trivalent 

3+ and ferromagnetic ordering has been observed with Curie temperature TC up 

to 170 K. It is expected that some of structural transition occurs due to magnetic 

symmetry braking below TC. In the present work, spontaneous magnetostriction of 

ferromagnetic RAl 2 compounds are studied from the X-ray diffraction measurement at 

low temperature and the thermal expansion of the single crystal. The X-ray diffraction 

pattern shows the d-spilliting at several peaks of TbAl 2 and DyAl 2 due to the large 

magnetic anisotropy below TC. From these results, the crystal structures are estimated 

at ferromagnetic phase of TbAl 2 and DyAl 2. The anisotropic magnetoelastic constants 

have been calculated by using the results of the magnetization and the magnetostriction 

at the ferromagnetic phase and at the magnetic field up to 2 T.

QJ13 

Influence of weak-magnetic, non-magnetic and disoriented grains on 

remagnetization processes of Nd-Fe-B alloys 

Anna Starikova*, Alexey Lileev and Olga Arinicheva 

National University of Science and Technology 'MISIS' (MISIS), Russia 

The uniaxial high-anisotropic materials, in which magnetostatic interaction between 

volumes have a significant influence were investigated. The analysis of domain 

structure formation during magnetization reversal these materials in the presence of 

weak-magnetic, non-magnetic and disoriented grains was carried out. The modeling 

ensemble simulating magnetic properties of sintered alloy neodymium- iron - boron 

(Nd 15Fe 77B 8) was selected. Research of influence of inclusions was conducted on the 

basis of model experiments with the received ensemble. The program, devised for 

uniaxial high-anisotropic ferromagnetics, in which the sample is presented by ensemble 

from 1000 particles having transitive domain structure and following individual 

characteristics was used. After selection of all parameters of the ensemble simulating 

this material, for researching the influence of inclusions on magnetic reversal processes, 

key parameters of some microvolumes (Мs, Номах, Нs, Angle) were changed. It was 

concluded that magnetic reversal is realized by the channels formed at the expense 

of directed magnetostatic interaction. Weak-magnetic, non-magnetic and disoriented 

grains are the magnetic reversal centers, i.e. they are the beginning of formation of the 

channel of magnetic reversal. 

QJ14 

Cobalt magnetism in HoCo 2 under pressure 

Jaroslav Valenta, Jiri Prchal*, Marie Kratochvilova, Martin Misek and Vladimir 

Sechovsky 

Department of Condensed Matter Physics, Charles University in Prague, Czech 

Republic 

HoCo 2 belongs to a group of RCo 2 (R = rare earth metal) compounds forming in the 

cubic Laves phase structure. The Ho localized 4f-electron magnetic moments coexist 

together with the itinerant Co 3d moments, which appear on the verge of magnetism, 

similar to the ErCo 2 system [1]. Below TC, the large exchange field due to the 

ferromagnetically ordered Ho moments polarizes the Co 3d-electron states and the 

emerged moments in the Co sublattice orient antiparallel to the Ho sublattice. Weak 

Co moments survive rather far above TC (= 79,5 K) in Co magnetic clusters remaining 

coupled antiparallel to paramagnetic Ho moments forming a parimagnetic phase. This 

causes a susceptibility anomaly at the parimagnetic transition temperature Tf (= 125 K). 

At low temperatures the easy magnetization direction changes at the spin-reorientation 

temperature TR = (16,4 ± 0,5) K. We will present variations of the three transition 

temperatures with applying hydrostatic pressure up to 3 GPa. TC and TR coincidently 

decrease with increasing pressure whereas TR increases. The results will be discussed 

in term of suppressing the Co magnetic moments and varying the exchange and crystalfield 

interactions with applying the hydrostatic pressure. 

[1] J. Herrero-Albillos et al., Phys.Rev.B 76 (2007) 094409. 

QJ15 

High-field magnetization study of ErCo2 Maurice Guillot 1 and Yildirhan Oner 2 * 

1 

1. Grenoble High Magnetic Field Laboratory, CNRS, BP166, 38042 Grenoble 

Cedex 9, France,, France 

2 

Department of Physics, Istanbul Technical University, Turkey 

In this work are presented new results on the magnetic properties of the ErCo 2 

compound in which three magnetic phases (ferrimagnetic, parimagnetic and 

paramagnetic) were proposed very recently. This study is based on the investigation 

of the magnetization under continuous high magnetic fields (up to 330 kOe at 4.2K 

and up to 230 kOe in the 4.2-300K respectively). At low temperatures the stability of 

the ferrimagnetic structure is shown although the saturation was never found. Special 

attention was paid to the 35-100K temperature range where the transitions between 

the different magnetic phases occur confirming of the parimagnetic” orderings. 

The transition temperature Tc from the ferrimagnetic to the parimagnetic phase 

increases from ? 34 to 62 K with the applied field. For the values of H smaller than 

100 kOe. At H values greater than this Tc remains constant at (62 ±5) K. The atomic 

magnetic moment of Co is independent of the magnetic structure is and in the order of 

1μBatom-1. 

QJ16 

QJ17 

QJ18 


Resonance, magnetic and neutron investigations of magnetic structures 

in Pr 1-xY xFe 3(BO 3) 4 system 

A Pankrats 1 , V Tugarinov 1 *, C Ritter 2 , D Velikanov 1 , I Gudim 1 and V Temerov 1 

1 Kirensky Institute of Physics SB RAS, Krasnoyarsk, Russia 

2 Institute Laue-Langevin, Grenoble, France 

The rare earth borates RFe 3(BO 3) 4 with the structure of the huntite mineral are interesting as materials with 

two magnetic subsystems with competing anisotropy. In this work we present data on antiferromagnetic 

resonance (AFMR), magnetic properties and neutron investigation of Pr 1-xY xFe 3(BO 3) 4 system. Our AFMR 

and neutron investigations [1-3] show that the last points of the system, YFe 3(BO 3) 4 and PrFe 3(BO 3) 4, 

are easy-plane (EP) and easy-axis (EA) antiferromagnets, respectively, confirming the magnetic data 

for R=Pr [4]. A dilution of the Pr 3+ subsystem by diamagnetic yttrium reduces the magnetic anisotropy 

of the Pr subsystem and can lead to a transition from EA to EP state at some yttrium content. The single 

crystals Pr 1-xY xFe 3(BO 3) 4 with x=0.25, 0.325, 0.5 and x=0.75 were grown. Magnetic and resonance 

investigations show that the crystals with x = 0.25 and 0.325 are EA antiferromagnets with the energy gap 

at T=4.2 K close to 75 and 60 GHz, respectively, but the crystals with x=0.5 and 0.75 are EP ones. Neutron 

investigations showed that the concentration transition from EP to EA state occurs via an inclined magnetic 

structure which was found for x=0.325.The concentration dependency of AFMR energy gap is studied at 

T=4.2 K. This work was supported by RFBR grant #10-02-00765. 

[1] A.I. Pankrats, G.A. Petrakovskii, L.N. Bezmaternykh, V.L. Temerov, Physics of Solid State, 2008, 

Vol. 50, p. 79. [2] Ritter C., Vorotynov A., Pankrats A., et al., J. Phys.: Cond. Matter., 2008, V. 20, 

p. 365209. [3] Ritter C., Vorotynov A., Pankrats A., et al., J. Phys.: Cond. Matter, 2010, V. 22, p. 

206002. [4] A. M. Kadomtseva, Yu. F. Popov, G. P. Vorob’ev et al, JETP Lett., 2008, V. 87, p. 45. 

Anisotropic transport and magnetic properties of PrGe single crystal 

Pranab Kumar Das, Neeraj Goyal, Ruta Kulkarni, Arumugam Thamizhavel and 

Sudesh Kumar Dhar 

Department of Condensed Matter Physics and Materials Science, Tata Institute of 

Fundamental Research, Mumbai, India 

The compounds RGe (R = La, Ce, Pr and Nd) crystallize in the two closely related CrB and 

FeB-type orthorhombic crystal structures, depending upon R and heat treatment. We have 

recently reported the anisotropic magnetic properties of CeGe in detail which crystallizes 

in the FeB-type crystal structure [1]. In continuation of our studies on RGe compounds, 

we report here the anisotropic properties of a single crystal of PrGe grown by Czochralski 

method. PrGe exhibits dimorphism in which the high temperature FeB-type structure 

transforms into CrB-type structure at lower temperatures [2]. From the powder X-ray 

diffraction we have confirmed that the grown single crystal of PrGe possesses CrB-type 

crystal structure with the space group Cmcm(#63). The anisotropic magnetic properties 

have been studied along the three principal crystallographic directions. From the magnetic 

and transport properties we find that PrGe exhibits two magnetic transitions at 44 K and 

41.6 K along [100] and [010] directions, whereas along [001] direction only a ferromagnetic 

ordering at 44 K is observed. The susceptibility data clearly indicate that the high temperature 

ordering is antiferromagnetic and the low temperature one is ferromagnetic. The specific heat 

capacity data also confirm the two magnetic transitions in PrGe. 

[1] Pranab Kumar Das, Neeraj Kumar, Ruta Kulkarni, S.K. Dhar and A. Thamizhavel, arXiv: 

1108.1291 [2] D. Hohnke and E. Parthe, Acta Crys. 20 (1966) 572. 

Theoretical investigation of the phase transition and the spin-gap 

behavior of the triangular antiferromagnet YbAl 3C 3 

Changhoon Lee 1 *, Myung-hwan Whangbo 2 , Juergen Koehler 3 and Ji-hoon Shim 1 

1 Chemistry, Postech, Korea 

2 Chemistry, North Carolina State University, USA 

3 MPI for Solid State Research, Stuttgart, Germany 

Ytterbium aluminum carbide YbAl 3C 3, first reported in 1992,[1] has recently attracted much attention 

concerning the nature of its phase transition at T* = 77 K.[2-4] YbAl 3C 3 containing triangular sheets of 

magnetic ions Yb 3+ (f13) undergoes a phase transition at T* = 77 K and exhibits a spin-gap behavior. 

The two model structures of YbAl 3C 3, proposed to explain these observations, give unreasonably 

short C-Al distances. These model structures were optimized by density functional calculations to 

find that the Model 2 structure is more stable than the Model 1 structure, with chemically reasonable 

C-Al distances, and that the phase transition at T* is a cooperative second-order Jahn-Teller distortion 

involving the layers of corner-sharing CAl5 trigonal bipyramids. The spin exchanges between nearestneighbor 

Yb 3+ ions, evaluated by density functional calculations for the optimized Model 2 structure, 

show that YbAl 3C 3 has a two-dimensional spin lattice described by three antiferromagnetic exchanges, 

but exhibits a spin-gap behavior because one exchange is substantially stronger than the other two. 

(1) Gesing, T. M.; Pottgen, R.; Jeitschko W.; Wortmann, U. J. Alloys Compd. 1992, 186, 321. (2) Kosaka, 

M.; Kato, Y.; Araki, C.; Mori, N.; Nakanishi, Y.; Yoshizawa, M.; Ohoyama, K.; Martin C.; Tozer, S. W. J. 

Phys. Soc. Jpn. 2005, 74, 2413. (3) Ochiai, A.; Inukai, T.; Matsumura, T.; Oyamada A.; Katoh, K. J. Phys. 

Soc. Jpn. 2007, 76, 123703. (4) Kato, Y.; Kosaka, M.; Nowatari, H.; Saiga, Y.; Yamada, A.; Kobiyama, T.; 

Katano, S.; Ohoyama, K.; Suzuki, H. S.; Aso N.; Iwasa, K. J. Phys. Soc. Jpn. 2008, 77, 053701. 


Poster Tuesday


QJ19 


First Principle Analysis for Pressure Effect on Charge Density Wave 

Phases of SmNiC 2 

Jae Nyeong Kim and Ji-hoon Shim* 

chemistry, POSTECH, Korea 

Using a first principles calculation, we have investigated pressure effect on the electronic 

structure anisotropies, Fermi surface properties, and transport properties of SmNiC 2 to 

check their effects on the charge density wave instabilities. Both band structure and electric 

conductivity results show that SmNiC 2 has quasi 1D electronic structure by Ni 1D chain 

along a axis. However hybridization between nearest Sm 1D chain makes its charge density 

wave (CDW) properties 2D like with CDW vector q 1=(0.5, 0.5, 0) and another weak CDW 

vector q R=(0.5, 0.5, 0.5) at -6 GPa. With increasing pressure, highly anisotropic change 

of lattice induces these CDW vector to become incommensurate with flattening Fermi 

surface (FS) in the [110] plane and suppressing FS in [111] plane. The FS nesting vector 

q 1 is gradually shifted from q 1=(0.5, 0.50, 0) at -6 GPa to q 1=(0.5, 0.56, 0) at 14 GPa, while 

q1=(0.5, 0.52, 0) at 0 GPa, coincide with experimental results. Also, q R=(0.5, 0.5, 0.5), which 

is significant local maximum at -6GPa, becomes almost saddle point like with its nesting 

vector shifting another points. We conclude that CDW strength along q 1 vector become 

stronger with flattening (more 1D like) FS, but CDW strength along q R vector become weak 

with highly anisotropic change of lattice. 

[1] S. Shimomura, C. Hayashi, G. Asaka, N. Wakabayashi, M. Mizumaki, and H. Onodera, Phys. Rev. Lett. 102, 076404 

(2009). [2] Alexander Wolfel, Liang Li, Susumu Shimomura, Hideya Onodera, and Sander van Smaalen, Phys. Rev. B 82, 

054120 (2010). [3] J. Laverock, T. D. Haynes, C. Utfeld, and S. B. Dugdale, Phys. Rev. B 80, 125111 (2009). 

QK01 

The magnetoresistance of sandwich-structure organic spin-valve 

Feng Li*, Fapei Zhang and Yu Xiao 

High Magnetic Field Laboratory, Chinese Academy of Science, China 

We studied the magnetoresistance (MR) effect in an organic spin-valve structure 

of ferromagnetic/organic semiconductor/ferromagnetic system theoretically using 

the spin-diffusion theory and Ohm’s law. Spin polarons and spinless bipolarons are 

assumed to be the main carriers in organic semiconductors. From the calculation, it 

is obtained that MR value increases with the increase of the polaron proportion and 

rapidly decreases with the increase of the thickness of organic layer. MR ratio can 

be enhanced remarkably when the interfacial resistances are spin related. We also 

investigated MR value dependence of the effects of the matching conductivity and the 

spin-polarization of ferromagnetic layer. 

QK02 

First-principles calculations investigation of interfacial roles in spindependent 

transport properties in OMTJs 

Shiheng Liang 1 , Dongping Liu 1 , Lingling Tao 1 , Hong Guo 2 and Xiufeng Han 1 * 

1 

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, 

Chinese Academy of Sciences, China 

2 

Department of Physics and Center for the Physics of Materials, McGill University, 

Montreal, Quebec, Canada 

Organic spin valves and organic magnetic tunnel junctions (OMTJs) are new and promising 

research fields and show advantages for spin-dependent transport due to relatively weak 

spin-orbital coupling and hyperfine interaction. Long-chain alkanoic acids usually form 

close-packed monolayer films with alkyl chains highly oriented on substrates. The 

characterization of stearic acid adsorbed on Ni(111) surface has been studied. Our results 

suggest that the stearic acid is chemically adsorbed on the Ni surface via a bidentate 

interaction with a distance of about 1.8 A. We also investigated spin-dependent transport 

characterization through two kinds of organic magnetic tunneling junctions (OMTJs), as 

Ni/1-stearic acid radical (1-SAR)/Ni and Ni/1,18-stearic diacid radical (1,18-SDR)/Ni. We 

found magnetoresistance (MR) of Ni/1-SAR/Ni is -19.6%, and it is 13.7% for Ni/1,18- 

SDR/Ni OMTJ. There is a magnetic proximity effect in the interface, and the magnetic 

decay rate is dissimilar in different interfaces. Due to interaction at hybrid organic/magnetic 

interface, the electronic properties of interfacial atoms are modified. These effects influence 

the spin-dependent transport properties, and there appears positive or negative tunneling 

magnetoresistance (TMR) due to different interface. Our results suggest, the interface 

between organic barrier and FM electrode play an important role in the transport behavior. 


QK03 

GMR properties on flexible polymer film with bending stress 

Joonhyun Kwon, Seungha Yoon, Seungkyo Lee, Jeonghyeon Lee and B. K. Cho* 

School of Materials Science and Engineering, Gwangju Institute of Science and 

Technology (GIST), Korea 

Recently, demands and researches about variable flexible devices have been 

constant. In other to satisfy such demands, researches about magnetic properties in 

flexible environment also have been continued. In these researches, the simple giant 

magnetoresistance (GMR) spin valve structure was deposited on flexible polymer films, 

then was induced by external tensile stress from repetitive bending fatigue. As bending 

samples, bending directions were decided whether parallel or transverse directions to 

easy axis directions of GMR structure. As a result, when increasing parallel bending 

times, switching field interval range of free layer also increased, inversely as increasing 

transverse bending times, coercivity of free layer also increased. Such tendency had 

opposite properties to inverse magnetostriction effect theory from the view of bending 

direction, because flexible films had larger elastic recovery forces than tensile forces 

after bending. Therefore we anticipate that such elastic recovery forces was the reason 

of opposite tendency from the aspect of direction. Based on these results, we clarified 

possibilities that the coercivity could be controlled without curvature, moreover axis 

behavior, e.g., easy axis or hard axis, also could be controlled without curvature and 

extra annealing processes. 

QK04 

Giant magnetoresistance in graphene nanoribbons: Geometry, 

interface and dephasing effects 

Stefan Krompiewski* 

Institute of Molecular Physics, Polish Academy of Sciences, Poznan, Poland 

Motivated by the ongoing debate on the role of external contacts on electronic transport 

through carbon nanostructures [1-3], we theoretically estimate the combined effects 

- due to (i) geometry, (ii) the way the external contacts are attached and (iii) possible 

dephasing processes - in graphene nanoribbon (GNR). The method is based on the 

tight binding model, the Green function technique and the Landauer-type formalism. 

It is shown that giant magnetoresistance in GNRs depends strongly not only on the 

aspect ratio of the sample and the current direction, but also on whether ferromagnetic 

electrodes are attached in the end- or side-contacted manner. Typically the former 

attachment is favorable for conductivity. However the observed tendency is that the 

higher conductive systems reveal the lower giant magnetoresistive effect, and vice 

versa. Accordingly, the dephasing usually decreases conductivity, thereby increasing 

the GMR. 

[1] X. Song et al, Nanotechnology 20 195202 (2009). [2] Y. Matsuda et al, J. Phys. Chem. C, 114, 

17845 (2010). [3] S. Krompiewski, Nanotechnology, 22, 445201 (2011). Acknowledgment This work 

was supported by the Polish Ministry of Science and Higher Education as a research project No. N 

N202 199239 for 2010-2013. 

QK05 

Negative magnetoresistance in ferromagnet/semiconductor/ 

ferromagnet structures with cubic dresselhaus spin-orbit-interaction 

Kenji Kondo* 

Laboratory of Quantum Electronics, Research Institute for Electronic Science, Japan 

We have investigated the spin transport in Ferromagnet (FM)/Semiconductor (SC)/ 

Ferromagnet (FM) structures with a central SC barrier exhibiting cubic Dresselhaus 

spin-orbit-interaction (SOI). The energy profile of the barrier is assumed to be a square 

with height V and thickness d along z-direction. The magnetoresistance (MR) ratio has 

been calculated for three different barriers, GaAs, GaSb, and GaAs without SOI as a 

function of barrier thickness. Both ferromagnets are assumed to be Fe. Intriguingly, 

MR ratios exhibit negative values for two different barriers in some range of thickness. 

For GaAs, the MR ratio is negative when the thickness is larger than 0.03 nm. For 

GaSb, the MR ratio is negative in the range of 0.02 to 0.9 nm, changing the sign 

gradually from negative to positive at a thickness of about 0.9 nm. Afterwards, its value 

increases monotonically and reaches a constant value at a thickness of 2.5 nm. We can 

attribute these phenomena to spin filtering effects caused by both the spin precession 

and the energy-splitting in the central SC region. Without SOI, the MR ratio shows 

positive value in all the range since the spin does not rotate in the barrier.

QK06 

Spin valve effect of NiFe/graphene/NiFe junctions 

Muhammad Zahir Iqbal, Muhammad Waqas Iqbal and Jonghwa Eom* 

Department of Physics & Graphene Research Institute, Sejong University, Korea 

Novel linear dispersion in graphene makes unique electronic properties such as 

ambipolar transport and Dirac particle quantum Hall effect. Although graphene was 

previously considered to be a physically unstable form until it was shown to exist 

on the Si substrate, various methods to synthesize graphene have been developed. 

Exploiting such superior electronic properties combined with recently developed large 

scale growth of graphene by chemical vapor deposition (CVD), has led to field effect 

devices integrated on a wafer scale showing promise for future electronic applications. 

In this paper, CVD-grown graphene is used as intervened spacer between two 

ferromagnetic electrodes. The device is composed of 55 nm thick NiFe film, graphene 

and 75 nm thick NiFe film. The current-to-perpendicular-to-plane magnetoresistance 

(MR) shows the spin valve effect. The increased resistance in the antiparallel 

configurations of magnetizations is due to the spin dependent scattering inside the 

magnetic films or at interfaces. A positive MR ratio of the order of 0.045% has been 

observed at 300 K and this signal grows up to 0.14 % at 10 K. The junction resistance 

is found to be monotonically increasing with temperature. Graphene functions as not a 

tunnel barrier but a resistive thin film between two NiFe electrodes. 

QK07 

Giant magnetoimpedance and photoinduced magnetoresistance effects 

in ferromagnet/SiO2/p-Si hybrid structures 

N. V. Volkov*, A. S. Tarasov, E. V. Eremin, A. V. Eremin, S. N. Varnakov and S. G. 

Ovchinnikov 

L.V. Kirensky Institute of Physics SB RAS, Russia 

We report the electron transport properties in the Fe/SiO 2/p-Si hybrid structure. The 

results of dc studies show that the features of the transport properties of the structure 

are caused by a metal/insulator/semiconductor transition with a Schottky barrier 

formed at the SiO 2/p-Si in-terface [1]. The magnetoresistance effect is determined by 

contributions of the processes occurring in the volume of a semiconductor and in a 

inversion layer near the SiO 2/p-Si inter-face. Study of the impedance Z = R + iX and 

magnetoimpedance allows separating the dynamic contributions determined by charge 

and spin transport in different regions of the hybrid structure. The strongest effect of a 

magnetic field on R and X is caused by the presence of magnetic impurity centers in 

the semiconductor near the SiO 2/p-Si interface. Magnetoimpedance originates from 

spin-dependent tunneling between a ferromagnetic electrode and magnetic impurity 

centers via a potential barrier (SiO 2). The magnetic impurity centers determine also 

the change in photoconductivity in a magnetic field. The structure, as a matter of fact, 

exhibits giant magnetoresistance induced by optical radiation. As a mechanism of 

this effect, we consider the spin-dependent tunnel photocurrent, i. e., the current of 

photoexcited electrons, from p-Si to Fe via the SiO 2 barrier. 

1. N.V. Volkov, A.S. Tarasov, E.V. Eremin, et al., J. Appl. Phys. 109, 123924 (2011). 

QK08 

Charge imbalance with the same decaying length as spin accumulation 

Yao-hui Zhu* 

Physics Department, Beijing Technology and Business University, China 

Starting from the Valet-Fert theory of the current-perpendicular-to-plane giant 

magnetoresistance, we study the charge imbalance in ferromagnetic metals by 

solving Poisson's equation. Our results show that, in ferromagnetic layers, the charge 

imbalance has two exponential terms with different decaying lengths: the Thomas- 

Fermi screening length (on the order of angstrom) and the spin diffusion length (tens 

of nm in 3d ferromagnetic metals). The charge imbalance on the scale of the screening 

length has been well studied and it is also present in spin-unpolarized transport in 

nonmagnetic multilayers. However, the charge imbalance on the scale of the spin 

diffusion length has never been studied before and it shows up only in ferromagnetic 

layers with spin accumulation, which also decays on the scale of the spin diffusion 

length. This charge imbalance is essential to the giant magnetoresistance effect and 

thus one should be cautious when using quasi-neutrality condition, which neglects the 

charge imbalance. 

[1] T. Valet and A. Fert, Phys. Rev. B 48, 7099 (1993). [2] Y.-H. Zhu, B. Hillebrands, and H. C. 

Schneider, Phys. Rev. B 78, 054429 (2008). [3] S. Zhang, Phys. Rev. Lett. 83, 640 (1999). 

QK09 

QK10 

QK11 


Simulation of spin-dependent transport in GaAs: Effect of electronelectron 

interactions 

Matthew Hodgson, Gionni Marchetti, Roy W. Chantrell and Irene D'amico 

Physics, University of York, United Kingdom 

We investigate the effect of electron-electron interaction on electronic spin transport in 

bulk GaAs. We use Ensemble Monte Carlo (EMC) techniques to simulate the electron 

and spin dynamics. EMC has been successfully used in the study of charge transport 

and more recently in spin transport. However electron-electron interactions are often 

neglected, also due to computational costs. Here, in addition to electron-electron 

scattering we include scattering from optical and acoustic phonon, and charged defect 

scattering. Spin decoherence occurs due to the spin-orbit interaction (Dresselhaus 

term), which arises from the lack of inversion symmetry in GaAs. The electron-electron 

interaction is described by the screened Coulomb potential. At variance with previous 

simulations, we implement both spin dependent (Mott) and spinless (Rutherford) 

scattering. We also propose a new, more realistic, method for choosing partners 

undergoing electron-electron collisions which properly accounts for the dependence on 

the distance between electrons. We show that, in EMC simulations, electron-electron 

interactions should not be discarded, as doing so may result in an anomalous drop in 

the spin relaxation time at temperatures as high as 100K. 

Electrical detection of spin-polarized current in InAs quantum point 

contacts 

Taeyueb Kim 1, 2 , Sungjung Joo1, Jinki Hong 1 *, Kungwon Rhie 1 , Hyuncheol Koo 2 *, 

Jindong Song 3 , Joonyeon Chang 2 , Sukhee Han 2 , Kyungho Shin 2 

1 Department of Applied Physics, Korea University, Chochiwon, Korea 

2 Spin device research center, Korea Institute of Science and Technology, Seoul 136-791, Korea 

3 Nano Photonics research center, Korea Institute of Science and Technology, Seoul 136-791, Korea 

The controlled generation, manipulation and detection of spin-polarized currents in semiconductor 

is an important issue in spintronic devices [1]. The Rashba spin-orbit interaction has been focused to 

manipulate spin currents. Furthermore, the quantum point contact (QPC) having the Rashba interaction 

was recently proposed as a spin-current generator. [2], [3] In this work QPCs were fabricated from InAs 

quantum well. Gates were installed on the sides of the quantum well, and narrow conducting channels, i.e. 

QPC, were formed by application of voltages on theses gates. Two QPCs were connected in series and the 

distance between them was less than 1.6 micro-meter. An external magnetic field was applied in parallel 

with the line connecting the two QPCs. Oscillations of resistance according to the magnetic field have 

been observed in this device at 1.8K. We believe that these data can be an evidence for our QPCs to work 

as a spin polarizer with a following scenario; the first QPC works as a spin-polarizer, and the second does 

as a detector. The spin-current produced by the first QPC precesses by the external magnetic field, which 

makes the oscillatory resistance as the magnetic field changes. 

[1] Mikio Eto, Tetsuya Hayashi and Yuji Kurotani, J. Phys. Soc. Jpn. 74, 7, 193(2005) [2] P. Debray, S. M. S. 

Rahman, J. Wan, R. S. Newrock, M. Cahay, A. T. Ngo, S. E. Ulloa, S. T. Herbert, M. Muhammad and M. Johnson, 

Nature Nanotech. 4, 759 (2009) [3] A. Reynoso, Gonzalo Usaj, and C. A. Balseiro , Phys. Rev. B. 75, 085321 (2007) 

Gate dependence of spin-orbit interaction in a two-dimensional hole 

gas structure 

Youn Ho Park 1 , Hyun Cheol Koo 1 *, Sang-hoon Shin 1 , Jin Dong Song 1 , Hyung-jun 

Kim 1 , Joonyeon Chang 1 , Suk Hee Han 1 and Heon-jin Choi 2 

1 Spin Device Research Center, Korea Institute of Science and Technology, Korea 

2 Department of Materials Science and Engineering, Yonsei University, Korea 

In order to implement spin-Field Effect Transistor (spin-FET), gate control of spinorbit 

interaction parameter (α) is a key factor in a quantum well structure because spin 

precession is influenced by strength of the α [1]. Many papers utilized n-type channel 

for the spin transport, however, for the complementary logic device p-type channel 

should be also necessary. We have investigated the spin-orbit interaction parameter 

and the effective mass using the Shubnikov-de Haas (SdH) oscillation measurement 

in a GaSb two-dimensional hole gas (2DHG) structure. The α of 1.71 × 10^11eVm 

and effective mass of 0.98m0 are obtained at T = 1.8 K, respectively. We also found 

the gate dependence of the α and the hole concentration at 1.8 K. As increasing the 

gate voltage both the α and the hole concentration are reduced, which indicates the α 

increases with the carrier concentration in p-type channel. On the order hand, n-type 

channel shows opposite gate dependence [1, 2]. Therefore, the combined device of p 

and n-type channel spin transistor would be a good candidate for the complimentary 

logic device. 

[1] H. C. Koo, J. H. Kwon, J. Eom, J. Chang, S. H. Han, and M. Johnson, Science, 325, 1515 (2009). 

[2] J. Nitta, T. Akazaki, and H. Takayanagi, Phys. Rev. Lett. 78, 1335 (1997). 


Poster Tuesday



QK12 

Perpendicular spin transport in ferromagnet/MgO/GaAs structures 

Joohyung Bae 1 , Kyung-ho Kim 1 , Hyun Cheol Koo 1 *, Hyung-jun Kim 1 , Joonyeon 

Chang 1 , Suk Hee Han 1 and Sang Ho Lim 2 



The electrical spin transport from TbFeCo/CoFeB into GaAs using MgO tunnel barrier 

is investigated. The 20 nm thick TbFeCo layer produces perpendicular magnetization 

and the 0.8 nm thick CoFeB layer, which contacts the MgO/GaAs layer, enhances the 

spin polarization of the injector. The MgO layer has a role of spin filter for efficient 

spin injection. In order to reduce the contact resistance, the heavily doped GaAs 

layer is inserted between TbFeCo/CoFeB/MgO and GaAs substrate. We measured 

spin accumulation and spin lifetime using three-terminal Hanle measurements with 

temperature range from 1.8 K to 300 K. In this geometry, the bias current is applied 

from the top TbFeCo layer to the GaAs channel and the voltage is measured at the 

interface. The perpendicular spin is injected so the in-plane magnetic field is swept to 

observe the spin relaxation at the interface. For a bias current of 1.5 mA, the spin signal 

of 0.12 mV and 0.03 mV are obtained at T = 1.8 K and 300 K, respectively. From the 

analysis of the Hanle curve, a spin life time of 0.4 ns is extracted at 300 K. 

QK13 

Spin hall effect in 2DEG in the presence of Rashba spin-orbit 

interation 

Won Young Choi, Hyung-jun Kim, Joonyeon Chang, Suk Hee Han and Hyun Cheol 

Koo* 

Korea Institute of science and technology, Korea 

Spin Hall effect using an InAs-based 2DEG system with a strong Rasba effect is 

researched. To make all electric devices, permalloy is used as spin injector on Hall 

bar geometry. Two kinds of equivalent measurement, inverse and direct spin Hall, are 

performed. Inverse and direct spin Hall are the conversion of spin to charge and charge 

to spin, respectively. Also to confirm the effect of precession, dependences of channel 

length and magnetization direction are systematically investigated. The bias current 

between ferromagnet and neutral region of channel induces the injection of in-plane 

spin. Inside the channel, spin precession occurs and then spin orientation is changed to 

the perpendicular direction at the Hall cross. The spin signal as a function of channel 

length shows oscillation behavior which is also evidence of spin precession. At 1.8K, a 

spin Hall voltage of 4 μV is detected for a bias current 0.1 mA and a channel length of 

0.64 μm. From this experiment, we confirm the spin Hall effect and spin precession at 

the same time. 

[1] J. Wunderlich, B. G. Park, and A. C. Irvine et al, Science 330, 1801 (2010) [2] L. Sheng, D. N. 

Sheng, and C. S. Ting, PRL 94, 016602 (2005) [3] H. C. Koo, J. H. Kwon, J. Eom, J. Chang, S. H. 

Han, and M. Johnson, Science 325, 1515 (2009). 

QK14 

Spin transport and spin injection into turbostratic graphene 

June Seo Kim 1 , Sebastian Schweitzer 2 , Ajit K Patra 2 , Yenny Hernandez 3 , Klaus 

Muellen 3 , Xinliang Feng 3 and Mathias Klaeui 1 * 

1 Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, Germany 

2 Fachbereich Physik, Universitaet Konstanz, Germany 

3 Max Planck Institute for Polymer Research, Germany 

The remarkable physical properties of graphene, a monolayer of carbon atoms packed into a twodimensional 

hexagonal lattice, make it a promising material for applications, In particular, the high 

electron mobility [1] and the relatively long spin lifetime (weak interaction of the electrons spin 

and orbital degree of freedom [2]) resulting in long spin diffusion lengths λ up to 2 μm [3], make 

it an interesting candidate for spintronics. However, λ is currently limited by the strong interaction 

between graphene and the underlying substrate and by the intrinsic corrugation of mechanically 

exfoliated graphene sheets. This can be overcome by using turbostratic graphene (TG), a multilayer 

graphene stack consisting of tens of electronically decoupled layers. TG combines the exciting 

properties of graphene with the higher robustness to environmental influences and the absence of 

inner corrugations of a microstructured material [4]. In this study, we have successfully performed 

spin injection from ferromagnetic electrodes into TG discs and detected the spin transport using a 

non-local spin valve configuration [3]. Moreover we can also investigate the correlation between 

the charge carrier transport properties and the spin injection efficiency. 

[1] A. K. Geim et al., Nature Materials 6, 183 (2007), Science 324, 1530 (2009). [2] Hernando et 

al., Phys. Rev. B 74, 155426 (2006). [3] N. Tombros et al., Nature 448, 571 (2007). [4] M. Orlita et 

al., Phys. Rev. Lett. 101, 267601 (2008). 


QK15 

Spin signal in metallic lateral spin valves made by a shadow 

evaporation technique 

Piotr Laczkowski, Laurent Vila, Williams Savero-torres, Van Dai Nguyen, Juan Carlos 

Rojas-sanchez, Murat Cubukcu, Alain Marty, Lucien Notin, Cyrille Beigne and Jeanphilippe 

Attane 

Universite Joseph Fourier, BP 53, 38041, Grenoble and INAC/ CEA Grenoble, 

France 

Amidst the large variety of proposed spin structures, Lateral Spin Valves (LSV) devices attracted 

recently an increasing attention. These lateral devices consist in two ferromagnetic electrodes 

connected by a non-magnetic metallic wire allowing to tune the transport properties according to the 

respective magnetic states of the two ferromagnetic electrodes. They allow realizing non-local transport 

measurements, by separating the spin current from the charge current using a four probe connections 

to an interface. We are developing non-local spin injection and detection technique in lateral spin valve 

structure made by electron beam lithography and angle evaporation techniques with a special emphasis 

on the study of the spin Hall effect. The spin signal depends mainly on the geometry of the LSV, on the 

quality of the interfaces, and on the choice of the used materials. We present a method used to optimize 

the spin signal of lateral spin valves using a technique to form and connect nanowires in a single step 

in vacuum, avoiding interface contamination and oxidation. By using different evaporation angles of 

materials through a resist mask and by reducing the devices geometry, we succeeded in obtaining spin 

signals close to 25 mΩ at 77K in devices with transparent interfaces. 

P. Łaczkowski et al., Applied Physics Express, Volume 4, Issue 6, pp. 063007-063007-3 (2011) 

QK16 

Hanle effect with in-plane magnetic fields in metallic lateral spin valves 

Juan-carlos Rojas Sanchez, Laurent Vila, Matthieu Jamet, Piotr Laczkowski, Murat 

Cubukcu, Williams Savero-torres, Van Dai Nguyen, Alain Marty, Cyrille Beigne and 

Jean-philippe Attane 


France 

When a charge current crosses the interface between a ferromagnetic (FM) and a nonmagnetic 

(NM) material, a spin current appears that occurs on the length scale of the 

spin diffusion. It is possible to detect this spin accumulation by measuring the voltage 

between the NM wire and the other FM wire. We show that the spin signal amplitude 

can be enhanced by inserting a natural Al oxide between the interface of Py and Al, 

achieving spin signals above 150 mOhms at 77 K (instead of 24mOhms with transparent 

contacts) and 38 mOhms at RT. When the magnetic field is applied perpendicularly to 

the LSV plane, the injected spins in the normal channel precess around an axe parallel 

to H. The decoherence and/or the precession induced by the magnetic field can lead to 

oscillations and disappearance of the spin signal (Hanle effect). Hanle measurements 

are usually performed by applying H perpendicular to the sample plane [1], the spin 

precessing in plane. Here we show that it is possible to carry out Hanle measurements 

by applying H in the sample plane, generating out-of-plane spin precession, and thus 

gaining a degree of freedom for the control of the spin current. 

[1] “Electrical detection of spin precession in a metallic mesoscopic spin valve” F.J. Jedema, H.B. 

Heersche, A.T. Filip, J.J.A. Baselmans and J. van Wees, Nature 416, 713 (2002). 

QK17 

Detecting the magnetization switching of a ferromagnetic dot using 

non local spin injection by means of lateral spin valve structures 

Williams Savero-torres, Laurent Vila, Alain Marty, Piotr Laczkowski, Van Dai 

Nguyen, Murat Cubukcu, Juan-carlos Rojas Sanchez, Lucien Notin and Jean-philippe 

Attane 


France 

In most researches on Spin Torque, the charge and spin currents cannot be separated. To solve 

this problem, spin injection using lateral spin-valves, made of magnetic and non magnetic 

materials, have been proposed [1]. In this context, we study the spin torque generated by pure 

spin current on a ferromagnetic dot, using lateral spin-valve structures. The nanostructure 

is composed of two parallel ferromagnetic electrodes, one transversal metallic channel, and 

one ferromagnetic dot at the middle of the structure. The width of wires and dots is 50 nm. 

To detect the dot magnetization switching, non-local measurements are performed. The spin 

polarised current is injected on one side using a ferromagnetic electrode. The spin accumulation 

produces the splitting of the electrochemical potential, enabling the diffusion of the pure spin 

current along the channel. The pure-spin current is found to be adsorbed by the ferromagnetic 

dot, decreasing the spin signal amplitude, which is detected using the second ferromagnetic 

electrode. The non local geometry enables the spin current and the charge current separation, 

giving the possibility to test the magnetization switching induced by a pure spin current. 

[1] T. Yang, T. Kimura, and Y. Otani, Giant spin-accumulation signal and pure spin-current-induced 

reversible magnetization switching, Nat. Phys. 4, 851 (2008).

QK18 

Perfect spin filter and highly spin-polarized current induced by fano 

antiresonance effect in the multiple-quantum-dot nanodevices 

Hua-hua Fu 1 , Kai-lun Yao 2 * and Zu-li Liu 2 

1 

Department of Physics, Huazhong University of Science and Technology, Wuhan 

430074,, China 

2 

Physics Department, Huazhong University of Science and Technology, Wuhan 

430074,, China 

To realize perfect spin filter or to generate highly spin-polarized current is one of the fundamental 

requirements of any applications on spintronics, and in what material or model structure to achieve this 

goal effectively is still one of the central issues in spintronics. To realize these aims, multiple-quantumdot 

system which can be man-made in a controllable way have been attracted much attention. In this 

report, we propose a practical design to realize perfect spin filter in a periodic diamondlike network 

composed of multiple quantum dots (QDs). In our design, by producing an energy difference between 

the site energy between the upper and down QDs in the network, the conductance spectra show 

a valley structure with a zero point due to the Fano antiresonance effect. As the energy difference 

increases or the network size increases to a not very large value, the antiresonance valley changes to a 

well-defined insulating band. Moreover, the conditions for the occurrence of the Fano antiresonance 

and its relation with the formation of the well-defined insulating band are determined. By a Zeeman 

effect, the spin-splitting conductance spectra show several highly to 100% spin-polarized windows, 

strongly proposing that this network can be applied as a perfect spin filter. 

1. H. H. Fu, K. L. Yao, Appl. Phys. Lett. 110, 013502, 2012. 2. H. H. Fu, K. L. Yao, J. Chem. Phys. 

134, 054903 (2011). 3. H. H. Fu, K. L. Yao, J. Appl. Phys. 108, 084510 (2010); 110, 094502 (2011). 

QK19 

Transmission of spin polarized photoelectrons across ferromagnet/ 

semiconductor interfaces using oblique Hanle effect 

Yasuhiro Shirahata 1 , Toshiyuki Isozaki 1 , Ippei Suzuki 1 , Eiji Wada 1 , Mitsuru Itoh 1 , 

Masahito Yamaguchi 2 and Tomoyasu Taniyama 1 


2 Department of Electrical Engineering and Computer Science, Nagoya University, 

Japan 

We demonstrate spin-dependent transmission of photoelectrons from a GaAs quantum 

well (QW) into a ferromagnetic FeGa layer under optical spin orientation in a small 

oblique magnetic field. The application of the oblique magnetic field enables us to 

measure the spin-dependent electron transmission across the interface due to the inplane 

spin component of photoelectrons caused by the Larmor precession of electron 

spins about the magnetic field. A clear field dependence of the spin-dependent 

photocurrent is observed for a 20-nm-thick FeGa/GaAs QW sample, showing that 

the filtering of in-plane polarized electron spins which are generated by the Larmor 

precession occurs at the interface. To get concrete evidence for the spin filtering effect, 

we measure the magnetic field dependence of the phase shift between the circular 

polarization of light irradiated and the spin-dependent photocurrent. The phase shift 

exhibits a hysteresis behavior as a function of magnetic field, in compatible with the inplane 

magnetization process of the FeGa layer. These results clearly demonstrate that 

a very efficient spin filtering effect occurs at the FeGa/GaAs interface even at a low 

magnetic field, providing a promising basis for designing spin detection technology 

based on spin filtering effect. 

QK20 

Electric field tunning and spin coulomb drag in spin field effect 

transistors (spin-FETs) 

George Alexandru Nemnes, Lucian Ion and Stefan Antohe 

University of Bucharest, Faculty of Physics, Romania 

The quasi-bound states which appear as a consequence of the Rashba spin-orbit (SO) coupling, 

introduce a strongly irregular behavior of the spin-FET conductance at large Rashba parameter 

[1]. However, by introducing stray electric fields in addition to the SO couplings, the effect 

of the SO induced quasi-bound states can be tuned. The oscillations of the spin-resolved 

conductance become smoother, resulting the possibility to control the spin-FET characteristics 

[2]. Besides these effects, the Coulomb interaction gives rise to new and interesting manybody 

phenomena. D'Amico et al. discussed recently the physical origin of spin Coulomb drag 

effect (SCD) in rather general three-, two- and one dimensional systems. Here, a step closer to 

a realistic device is made: the SCD effect will be investigated in a nanowire spin-FET structure 

within the framework of self-consistent calculations for the open quantum system [3]. The spin 

drag trans-resistivity as a measure for SCD effect will be obtained, in the context of adjusting 

the spin injection efficiency from the contacts. In addition, the SCD effect in the presence of 

Rashba spin-orbit coupling will be analyzed. The Coulomb interaction will also be introduced 

in an exact manner for a few electron system, using the exact diagonalization method [4]. 

[1] M. M. Gelabert et al., Phys. Rev. B 81, 165317 (2010). [2] G. A. Nemnes, A. Manolescu, V. 

Gudmundsson, IOP - JPCS (to be published, 2012). [3] G. A. Nemnes, L. Ion, and S. Antohe, J. 

Appl. Phys. 106, 113714 (2009). [4] C. Yannouleas and U. Landman, Rep. Prog. Phys. 70, 2067 

(2007). 

QK21 

QK22 

Geometry effect on quasi-twodimensional electron system 

Kuo-chin Chen, Hsin-han Lee and Ching-ray Chang* 

National Taiwan University, Taiwan 

QK23 


The Rashba-type Spin splitting in Pb monolayer on Si and Ge 

surfaces: a First-principles study 

Hyungjun Lee 1 and Hyoung Joon Choi 2 * 

1 Department of Physics, Yonsei University, Korea 

2 Department of physics, Yonsei University, Korea 

Rashba spin-orbit splitting of the surface states due to structural inversion asymmetry 

is a rapidly growing field of research. Specifically, owing to a technological importance 

in spin-dependent electronics, spin-polarized metallic surface states on semiconductor 

surfaces would be highly interesting. Along this line, we have performed first-principles 

calculations of electronic structures of monolayer of heavy element deposited on 

semiconductor surfaces, Pb/Si(111) and Ge(111)-√3×√3 surfaces, by including the 

spin-orbit coupling in the form of additional nonlocal pseudopotential projectors. 

We investigate and compare energy band dispersions and spin polarizations of these 

systems and simulate angle-resolved photoemission spectra for direct comparison 

with experimental results. We also discuss our results focusing on the difference from 

the Rashba splitting in the Shockley surface states on Au(111) surface. This work 

was supported by the NRF of Korea (Grant No. 2011-0018306), and computational 

resources have been provided by KISTI Supercomputing Center (Project No. KSC- 

2011-C3-06). 

We calculate the local charge density and local spin density in a deformed square lattice 

system with Rashba spin orbital interaction. Use nonequilibrium Keldysh Green’s 

function formalism, within the tight-binding framework. The system consists of normal 

metal lead and deformed central part. We treat the deformed system as adding effective 

magnetic field that introduces Zeeman effect. We also present the charge and spin 

current. The deformation we adopt is hemispherical shape and Gaussian shape. We will 

compare the result with the case that deformation vanished. 

Electrical measurement of spin accumulation and transport in Fe/ 

AlGaAs heterostructures 

Joon-il Kim 1 *, Jennifer Misuraca 1 , Kangkang Meng 2 , Jun Lu 2 , Lin Chen 2 , Jianhua 

Zhao 2 , Stephan Von Molnar 1 and Peng Xiong 1 

1 

Physics, Department of Physics, Florida State University, Tallahassee, Florida, 

USA, USA 

2 

Physics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, 

China 

Utilizing the persistent photoconductivity effect, we report on spin accumulation and transport 

in AlGaAs at different carrier densities under the same experimental conditions without the 

necessity for making replicas to access different doping levels. We conducted non-local 3 

and 4 terminal Hanle effect measurements in AlGaAs to measure spin accumulation and 

spin transport respectively at different carrier densities. We will present our recent results, 

especially the carrier density dependence of the spin lifetime derived from our non-local spin 

measurements. We also report the bias current dependence of the spin lifetime. From optical 

studies, the spin life-time at zero bias and at low temperature was reported to be larger than 100 

ns in n-GaAs on the insulating side and ~80 ns on the metallic side [1]. Based on our non-local 

3 terminal measurement in Si:Al 0.3Ga 0.3As, the extrapolated spin life-time at zero bias and at 5 

K was found to be as large as ~2 ns on the insulating side and decreased with increasing bias 

current. This work was supported by NSF DMR-0908625 and NSFC 10920101071. 

[1] M. Furis, D.L. Smith, and S.A. Crooker and J.L. Reno, Appl. Phys. Lett. 89, 102102 (2006). 


Poster Tuesday



QK24 

Pure spin current injection into a Gd wire 

Seiji Nonoguchi, Tatsuya Nomura and Takashi Kimura* 

Kyushu University, Japan 

In magnetocaloric effects, the spin entropy is transformed to the thermal entropy 

because of an interaction between spin and heat. Since the spin entropy can be 

controlled by the external magnetic field, the environment temperature also can 

be tuned by the external magnetic field. Although such methods can be operated 

efficiently, it is difficult to reduce the size of the entire system. An effective magnetic 

field can be produced also by injecting spin currents via the interaction between the 

conduction electrons and localized magnetic moments. Therefore, when a pure spin 

current is injected into the magnetocaloric material, we may control the spin entropy 

because of the spin transfer torque and/or spin accumulation. Such a cooling effect has 

a possibility for a highly efficient nanosized refrigeration device. To demonstrate this 

effect, we prepared a lateral spin valve with the Gd middle wire, which is a magnetocaloric 

material. We observed the reduction of nonlocal spin signal by inserting the 

middle Gd wire, meaning the pure spin current was injected into the Gd wire. We 

also found that the background resistance decreases with increasing DC current. This 

implies that the device was cooled by the pure spin current injection into the Gd wire. 

QL01 

Synthesis and characterization of Ba 3Co 2Fe 24O 41 by the proteic sol-gel 

process 

Bruna Andrade, Petrucio Silva and Marcelo Macedo* 

Physics, Federal University of Sergipe, Brazil 

In this work, we show the production of hexagonal Z-type barium ferrite ( 

Ba 3Co 2Fe 24O 41) prepared via the proteic sol-gel process as well as their structural 

characterization and magnetic properties. The precursor materials were iron nitrate, 

cobalt nitrate and barium carbonate which formed a sol after being stoichiometrically 

dissolved in coconut water. We carried out a heat treatment at 100°C/24 h for the 

formation of an amorphous xerogel and a calcination at 1000°C/1 h for phase formation 

of Z-type barium ferrite. The material exhibited a magnetization curve as a function of 

temperature characteristic of ferrimagnetic material with Tc > 300 K and a hysteresis 

at room temperature with low coercive field (142 Oe) and saturation magnetization 

around 48 emu/g for a field of 7 T. Our results indicate that the proteic sol-gel process 

may be a route of great potential for obtaining Z-type ferrites. 

QL02 

Ferromagnetism in vanadium doped ZnO thin films grown by pulsed 

laser deposition 

Shumaila Karamat 1 *, Rajdeep Singh Rawat 2 , Paul Lee 3 , Tan Lee Augustine 4 , Raju V 

Ramanujan 5 and H.d Sun 6 

1 

Physics, 1. NIE, Nanyang Technological University, Singapore 2. COMSATS,Islamabad, Pakistan, 

Pakistan 

2 

Physics, National Institute of Education, Nanyang Technological University, Singapore, Singapore 

3 

Physics, NIE-NTU, Singapore, Singapore 

4 

Physics, NIE-NTU Singapore, Singapore 

5 

Material Science, MSE-NTU Singapore, Singapore 

6 

SPMS, SPMS-NTU, Singapore 

This paper investigates the structural, compositional and magnetic properties of vanadium doped ZnO films 

((ZnO) 1-x(V 2O 5) x where x = 0.02, 0.03 and 0.05) deposited by pulsed laser technique (PLD). Thin films were 

deposited for a constant duration of 1 hr at 2×10-2 mbar O2 ambient gas pressure by using frequency doubled 

Nd:YAG laser at 750 °C substrate temperature. The preferred orientation in thin films is along the (002) plane of 

ZnO. The lattice parameter c derived from the (002) diffraction peak increases as vanadium content increases, 

suggesting that vanadium substitutes for Zn in ZnO lattice. The PL measurement at low temperature shows 

the emission peak at 3.30 eV which is usually caused by acceptor-related transitions such as free electron to 

neutral acceptor (FA) and donor-acceptor-pair (DAP). The XPS results show that vanadium exist in V 2+ and 

V4+ valence state which is in agreement with the XRD and PL results and points to the fact that the ZnVO 

phase, desirable in DMS, is formed in thin film samples. Furthermore, the hysteresis curves exhibiting the 

ferromagnetism for all thin films samples further support the formation of ZnVO phase in thin films samples. 


QL03 

The magnetic and dielectric properties of multiferroic Bi 1-xGd xFeO 3 

Takuya Yanoh*, Naoki Sakai, Liming Zhu, Akinobu Kurokawa, Hiromasa Takeuchi, 

Shinya Yano, Kazuki Onuma, Takaya Kondo, Kazunari Miike, Toshiki Miyasaka and 

Yuko Ichiyanagi 

Physics, Yokohama National University, Japan 

BiFeO 3 is known as multiferroic material with antiferromagnetic and ferroelectric 

properties. Especially, ferroelectricity at room temperature is remarkable and BiFeO 3 is 

expected for new device materials. However, BiFeO 3 has antiferromagnetic ordering, 

as the result, magnetic values such as remanent magnetization Mr and coercive force 

HC are rather small for further application. In this study, in order to improve magnetic 

property and to evaluate dielectric property, we tried to synthesize Bi 1-xGd xFeO 3 

particles where x = 0 to 1.0 by our original wet chemical method. The structural, 

magnetic and dielectric properties of prepared samples were investigated. Crystal 

structure change from rhombohedral to orthorhombic was found around x = 0.2 from 

the X-ray diffraction (XRD) measurement. Lattice constants a and c estimated by XRD 

decreased as Gd ion increased, supporting that Gd ions were doped exactly in BiFeO 3. 

The magnetic properties of Bi 0.9Gd 0.1FeO 3 which has rhombohedral (BiFeO 3 type) 

structure exhibited canted antiferromagnetism at 5 K. Both remanent magnetization 

Mr and coercive force HC significantly increased as Gd ion increased compared with 

BiFeO 3. The dielectric properties of Bi 0.9Gd 0.1FeO 3 showed that dielectric loss (tanδ) 

has been drastically improved compared with that of BiFeO 3 for about 90%, while real 

dielectric constant ε’ decreased about 15%. 

QL04 

Double-exchange interaction in heavily Mn-doped CuO thin films 

Li Li, Bin Lv, Shen Wang, Jinzhu Cai, Wenqin Zou, Fengming Zhang* and Xiaoshan 

Wu 


RKKY exchange, double-exchange interactions are two main mechanisms which are 

proposed to explain the origin of ferromagnetism of Mn-doped CuO films. Consider 

that double-exchange interactions cannot produce long-range magnetic order at 

concentrations of magnetic cations of low percent, Heavily Mn-doped CuO films have 

been prepared by PEVCD in air and in O 2. The M-T and M-H curves show that the 

average magnetic moment of the films prepared in O 2 is larger than those prepared 

in air, which may attribute to the variation of Mn chemical valence state. Doubleexchange 

between Mn 2+ and Mn 3+ can be used to understand the ferromagnetism of 

CuO under heavily Mn-doping.. The Curie temperature varies slightly with the growth 

atmosphere. The structure and magnetic properties vary with the annealing parameters 

obviously, which may indicate that the strain and carriers may play roles on the double 

exchange. 

QL05 

Magnetic properties of Cu-doped GaN films grown by MBE 

Philipp R. Ganz 1 , Christoph Suergers 2 *, Gerda Fischer 3 and Daniel M. Schaadt 4 

1 

Institut fur Angewandte Physik and DFG-Center for Functional Nanostructures, 

Karlsruhe Institute of Technology (KIT), Germany 

2 

Physikalisches Institut and DFG Center for Functional Nanostructures, Karlsruhe 

Institute of Technology (KIT), Germany 

3 

Physikalisches Institut, Karlsruhe Institute of Technology (KIT), Germany 

4 

Institute for Energy Research and Physical Technologies, Clausthal University of 

Technology, Germany 

The magnetic properties of Cu-doped GaN films have been investigated in dependence 

of Cu doping level and film thickness. The films were epitaxially grown at different Cuto-Ga 

beam-equivalent-pressure ratios (BEPR) by molecular beam epitaxy on sapphire 

substrates with an AlN buffer and were characterized by scanning electron microscopy, 

energy dispersive x-ray spectroscopy, and x-ray diffraction. Within a narrow range of 

BEPR around 1 %, a ferromagnetic behavior with a Curie temperature higher than 400 

K is observed. For BEPR > 1 %, nonferromagnetic Cu-Ga islands are predominantly 

formed at the surface. The saturation magnetization of ferromagnetic films with BEPR 

= 1 % decreases with increasing film thickness. This suggests that the ferromagnetic 

behavior is due to defects created during the growth process and by the incorporation 

of Cu into GaN for BEPR ≤ 1 % leading to a long-range magnetic polarization.

QL06 

Magnetism and electronic transport of MnAs single nanostructures 

Federico Fernandez Baldis 1 , Marina Tortarolo 2 , Martin Sirena+, Laura Steren 3 , Victor 

Etgens 2 and Mahmoud Eddrief 2 

1 Centro Atomico Bariloche, Argentina 

2 Institut des NanoSciences de Paris, France 

3 Centro Atomico Constituyentes, Argentina 

The magneto-structural properties of MnAs thin films grown onto GaAs have recently 

drawn much attention due to its potential application in spintronics devices. The MnAs 

thin films exhibit a coexistence of a low-temperature ferromagnetic hexagonal phase (α) 

and a paramagnetic orthorhombic (β) one in a finite temperature range below the Curie 

temperature. When MnAs is grown onto GaAs[100], both phases are self-organized in a 

regular stripes array. This pattern is affected when the MnAs films are confined laterally 

to micrometric sizes and depends on the direction of the confinement. In this work, 

we present an investigation of the temperature dependence of the magnetic domain 

structure and magneto-transport properties of MnAs nanoribbons in order to determine 

the anisotropic response of the system, regarding both the magnetism and electronic 

transport. The confinement effects were examined at the low-temperature pure 

ferromagnetic phase and at the α-β phase-coexistence regime. Nanoribbons confined 

along the (I) α-MnAs[1120] and (II) α-MnAs[0001] directions were fabricated by 

e-beam lithography combined with optical lithography. The magnetic domain imaging 

was performed with a MFM, home-adapted for variable temperature measurements 

between 284K and 320K. The magneto-resistance and Hall effect measurements were 

made between 50K and 320K using a 9 Tesla superconducting magnet. 

QL07 

The generated antiferromagnetic and ferromagnetic states in 

nanocrystalline Cu-Cu 2O system and the consequences for spin 

chemistry 

Anatoly Yermakov 1 *, Michael Uimin 1 , Alexandre Korolyov 1 , Ilya Byzov 1 , Alexey 

Mysik 1 , Vladislav Maikov 1 and Mamoru Senna 2 

1 Institute of Metal Physics, Ural Branch of RAS, Russia 

2 Faculty of Science and Technology, Keio University, Japan 

Under investigations of nanocrystalline Cu-Cu 2O oxides it has been established that they 

actually possess heterogeneous magnetic states in nanoscale range. In nano-structured Cu-Cu 2O 

oxides, ferromagnetic (FE) and anti-ferromagnetic (AF) states are coexisting at above room 

temperature. The new idea based on the magnetic phase transformation from AF to FE state 

at an external field was suggested as a hypothesis to understand the variation of chemical rate 

transformations. The point is that a metamagnetic phase transition is accompanied by a variation 

of an electronic state of carrier from localized to delocalized one which can result in a variation 

of nanoreagents reactivity. In fact, the influence of magnetic field on the rate of chemical 

transformations, e.g. Cu ammonium complex formation using Cu-Cu 2O nanomaterials, as 

magneto-controlled reagents, has been reliably observed. Thus, the nanocrystalline copper 

oxides having a liquid-like potential are a remarkable example of energy-wise degenerated 

different magnetic states that can be operated by fairly weak external magnetic fields to control 

a rate of chemical transformations and other properties. We think the principle we here propose 

could be extended to other transition metal oxide nanoparticles with a similar electronic states. 

Thanks to RFBR Grants # 10-02-00323 and # 10-02-546 for support. 

QL08 

Unidirectional anisotropy observed in Fe film grown on GaAs at low 

temperature 

Seonghoon Choi 1 , Taehee Yoo 1 , S. Khym 1 , Sanghoon Lee 1 *, X. Liu 2 and J. K. 

Furdyna 2 



The magnetic anisotropy properties of Fe films have been investigated by planar 

Hall effect (PHE) measurements. A 4 nm thick Fe film was grown on a (001) GaAs 

substrate by MBE technique at room temperature. The field scans of the planar Hall 

resistance (PHR) at room temperature show an abrupt transition with hysteresis 

centered at zero field during the magnetization reversal, indicating the presence of 

symmetric magnetic easy axes in the film plane. However, the hysteresis in the PHR 

appeared to be shifted toward one field direction when the temperature decreased to 3 

K. This asymmetry in the magnetization reversal process at 3 K can be understood by 

introducing an unidirectional anisotropy field H ud. Interestingly, the direction of the H ud 

directly follows the direction of the cooling field. This indicates that the direction of the 

H ud is not fixed but can be changed by the cooling field. For the case of the cooling field 

along the [-1-10] direction, we obtained the values of cubic, uniaxial and unidirectional 

anisotropy fields by analyzing angular dependence of PHR. The magnitude of H ud 

was one order of magnitude smaller than other anisotropy fields although it caused a 

significant asymmetry in the PHR hysteresis. 

QL09 

QL10 

QL11 


Magnetic properties of hydrothermally synthesized ZnO 

nanostructures 

H Hadiyawarman, Kadek J. Parwanta, Bowha Lee and Chunli Liu* 

Department of Physics, Hankuk University of Foreign Studies, Korea 

We report the study on the ferromagnetism in ZnO nanostructures fabricated by 

hydrothermal method at low temperature and with three different pH values. No posttreatment 

was applied to all samples. X-ray diffraction shows that the samples possess 

typical wurtzite structure and have no other impurity phases. Magnetization properties 

of ZnO samples were measured. With the defect analysis based on low temperature 

photoluminescence spectroscopy, the effective defects contributed to the magnetic 

properties were investigated. The result suggests that oxygen defects and synthesis 

conditions play an important role in mediating the magnetic property in the undopped 

ZnO nanostructures. 

Electrical, magnetic and magnetoimpedance studies of LSMO thin 

film prepared by sol gel method 

Pawan Kumar and Ramanathan Mahendiran 

Physics, NUS, Singapore 

In this work, we have prepared La 0.7Sr 0.3MnO 3 by sol-gel method using Si (100) 

substrate and characterized the sample by XRD,dc magnetization, dc magnetoresistance, 

and atomic force microscopy. The sample is found to be ferromagnetic below 367 K 

from the magnetic measurement. Impedance spectroscopy study has been reported 

on the thin film for the first time. We have studied the ac electrical impedance (Z) in 

LSMO thin film as function of Temperature (T) and magnetic field in response to radio 

frequency (f=0.1-5MHz) ac current flowing directly through the sample. DC resistivity 

and Z (T) shows transition around 365K which is correspond to Tc of LSMO thin film. 

In Z (T) peaks around Tc decreases in magnitude with applied field (1KOe), which 

is not affected much in DC resistivity. Magnetoimpedance ΔZ/Z= -30% is observed 

in MHz frequency range. It is suggested that observed magnetoimpedance results 

from suppression of the high frequency transverse permeability by an external field. 

Our study suggests that magnetoimpedance in manganite thin films might find new 

application in radio frequency regime. 

References: (1). Gang Zou , Xian You, Pingsheng He, Materials Letters 62 (2008) 1785-1788. 

Differential conductance measurements in Ni nanoscale contact 

fabricated by electromigration 

Junya Sakai 1 *, Koichiro Ienaga 1 , Yuji Inagaki 1 , Hiroyuki Tsujii 2 , Ryuya Nomura 3 , 

Seiji Nonoguchi 3 , Takashi Kimura 4 and Tatsuya Kawae 5 

1 Department of Applied Quantum Physics, kyushu university, Japan 

2 Faculty of Education, Kanazawa university, Japan 

3 INAMORI Frontier Research Center, Kyushu University, Japan 

4 INAMORI Frontier Research Center, Kyushu University, Japan 


A zero-bias anomaly in differential conductance has been reported in atomic-size 

contacts fabricated from the ferromagnets, Fe, Co and Ni, which is considered to come 

from the Kondo effect [1]. This is interesting because the Kondo effect usually requires 

two species of atom and is thought to be incompatible with ferromagnetic interaction. 

In order to clarify the origin of Kondo effect in atomic ferromagnetic contact, we have 

studied the size dependence of the zero-bais anomaly in Ni nanoscale contacts by 

mechanical controllable break junction technique and observe the anomaly in a large 

size where the ferromagnetism appears[2]. In this presentation, we study differential 

conductance in Ni nanoscale contacts with decreasing the size by electromigration. 

In large size contacts, zero-bias anomaly is not observed. When the conductance is 

smaller than 200G0 (G0=2e2/h), the anomaly is clearly observed. 

[1]M. Reyes-Calvo et al., Nature 458, 1150 (2009) [2]K. Ienaga et al., to be published. 


Poster Tuesday



QL12 

Magnetoresistance measurements in Pd atomic-scale contact at 4.2K 

Koichiro Ienaga 1 *, Naoya Nakashima 1 , Yuji Inagaki 1 , Hiroyuki Tsujii 2 and Tatsuya 

Kawae 1 


2 Faculty of Education, Kanazawa University, Japan 

QL13 

QL14 

WITHDRAWN 

Differential conductance measurements in Cu-Mn atomic-scale 

contacts 

Koichiro Ienaga 1 , Naoya Nakashima 1 , Yuji Inagaki 1 , Hiroyuki Tsujii 2 and Tatsuya 

Kawae 1 * 

1 Dapartment of Applied Quantum Physics, Kyushu University, Japan 

2 Faculty of Education, Kanazawa University, Japan 

WITHDRAWN 

Tuning the magnetic interaction in carbon nanotube/NiO 

nanocomposite system 

S Chattopadhyay, S Giri and S Majumdar* 

Department of Solid State Physics, Indian Association for the Cultivation of Science, 

India 

We have prepared a series of nanocomposite materials with multi-walled CNTs and 

NiO nanoparticles by varying the concentration of nickel nitrate solution. Transmission 

electron microscopy shows that the average size of the nanoparticles is about 10 nm 

and they are predominantly embedded either on the inner or the outer wall of the 

multi-walled CNTs forming a quasi one dimensional arrangement. It is also observed 

that the particles are well separated and density of the product NiO nanoparticles 

increases systematically with increasing concentration of the nickel nitrate 

solution. DC magnetization measurement shows the presence of thermomagnetic 

irreversibility in the temperature variation of the magnetization data. In contrary to the 

antiferromagnetic bulk NiO, field dependence of magnetization reveals the presence 

of strong ferromagnetic interaction along with prominent exchange bias effect. These 

materials also show magnetization relaxation which is an indication of non-ergodicity 

in the magnetic ground state. This system provides a rare opportunity to externally 

fabricate the degree of isolation among the particles and to tune the interparticle 

magnetic interactions as well for performing a systematic investigation on the evolution 

of the magnetic ground state with the variation of the interaction strength. 


QL15 

Bias-voltage dependence of magnetotransport properties in codeposited 

Co-C granular thin films 

Jun-goo Kang 1 *, Masaki Mizuguchi 1 , Shiro Entani 2 , Seiji Sakai 2 and Koki Takanashi 1 



Granular systems consisting of ferromagnetic nanoparticles dispersed in a nonmagnetic 

matrix exhibit giant magnetoresistance (MR) due to spin dependent transport. Carbon-based 

nanocomposite thin films have large application potential as spin transport materials because 

long spin relaxation time is expected due to its weak spin-orbit interaction [1]. We have found 

that co-deposited Co-C films exhibit a large negative magnetoresistance (MR: 27.6% at 2 K) 

[2]. It is expected that the bias voltage dependence of MR includes significant information on 

the mechanism of the MR. In this study, the bias-voltage dependence of magneto-transport 

properties for Co-C granular thin films has been investigated. Co-C granular thin films were 

fabricated by a co-sputtering technique. The current (I)- bias-voltage (V) characteristics and the 

MR behavior of the Co-C films were measured at temperatures of 2-30 K in a two-terminal 

geometry with the electrical current and magnetic fields (up to 70 kOe) in the in-plane direction. 

It was found that the magnitude of the MR ratio changed remarkably with bias voltage. A clear 

increase in the MR ratio with bias voltage was observed, and it reached 66.6 % for V= 25 V. 

[1] S. Sakai, K. Yakushiji, S. Mitani, K. Takanashi, H. Naramoto, P. V. Avramov, K. Narumi, V. 

Lavrentiev, and Y. Maeda, Appl. Phys. Lett. 89, 113118 (2006). [2] R. Tang, M. Mizuguchi, H. Wang, 

R. Yu, and K. Takanashi, IEEE Trans. Magn. 46, 2144 (2010). 

QL16 

Switchable voltage control of the magnetic anisotropy in 

heterostructured nanocomposites of CoFe/NiFe/PZT 

Thang D. Pham 1 *, Hong T. M. Nguyen 2 , Dong H. Kim 3 , Tiep H. Nguyen 2 and Cuong V. 

Le 2 

1 Faculty of Engineering Physics and Nanotechnology, University of Engineering and 

Technology, Vietnam National University, Hanoi, Viet Nam 

2 Laboratory for Micro and Nanotechnology, University of Engineering and 

Technology, Vietnam National University, Hanoi, Viet Nam 

3 Department of Physics, Chungbuk National University, South Korea, Korea 

Heterostructures of nanostructured ferromagnetic (FM) and ferroelectric (FE) layers are 

of increasing interest due to the coupling between the magnetic moment and electric 

polarizations. In particular electric voltage, rather than the conventional magnetic field, can 

be directly used to control the magnetic properties of the magnetic layers. This magneticelectric 

coupling may open promising applications towards novel spin electronic devices 

with low power consumption and high-speed data access. In this article, we study on the 

crystallographic structure and magnetic properties of CoFe/NiFe/PZT heterostructures. In 

these nanocomposites, the magnetic behaviors, such as magnetization significantly changes 

in the presence of an applied voltage. The change also depends on the FM layer thickness, 

the magnetic field direction and it can reaches up to more than 100%. Furthermore we 

observed the switching in magnetization at suitable applied voltage. Besides, we present 

a phenomenological approach to investigate stress-induced magnetic anisotropy, which 

originated from magnetoelectric coupling between two FM and FE phases. 

QL17 

Origin of the ferromagnetism in scandium-doped ZnO thin films 

Mohammed Benali Kanoun*, Souraya Goumri-said, Udo Schwingenschlogl and 

Aurelien Manchon 

1 King Abdullah University of Science and Technology(KAUST), Saudi Arabia 

In recent years, there have been more startling discoveries in diluted magnetic semiconductors [1] 

achieving possible room-temperature ferromagnetism in undoped (ZnO [2]) and non-transition metaldoped 

(ZnO:C [3]) systems. ZnO--based materials serve as model systems for the dilute magnetic 

oxides and are among the most intensely studied systems so far [4]. Interestingly, Venkatesan et al [5] 

have shown that room temperature ferromagnetism is observed in Sc-doped ZnO films. We note that 

in the bulk phase Sc has different crystal structures and nonmagnetic properties. How different are their 

magnetic properties when doped in ZnO thin films? Why do experimental results differ so much? To 

answer these questions, we have carried out comprehensive first-principles theoretical investigations 

of energetics, electronic structure, and magnetic properties of Sc-doped ZnO (11-20) thin films. In this 

work, the ZnO thin film was modeled by a (1×2) seven-layer slab supercell having a wurtzite structure 

along the [11-20] surface orientation. Each slab was separated from the other by a vacuum region of 10 

A along the [11-20] direction. Even though Sc is not magnetic in its natural phase, we found that it is 

likely to order ferromagnetically in ZnO thin film, in agreement with experiment [5]. 

[1] T. Dietl et al., Science 287, 1019 (2000). [2] Q. Xu et al., Appl. Phys. Lett. 92, 082508 (2008). 

[3] C. Liu et al., J. Mater. Sci. 16, 555 (2005). [4] Q. Ma, D. B. Buchholz, and R. P. H. Chang, Phys. 

Rev. B 78, 214429 (2008). [5] M. Venkatesan, C. B. Fitzgerald, J. G. Lunney, and J. M. D. Coey, 

Phys. Rev. Lett. 93, 177206 (2004).

QL18 

Magnetic control of the hydrogen storage of hydrogen-injected ZnCoO 

Bum-su Kim 1 , Seunghun Lee1 1 Jong Moon Shin 2 , Yong-chan Cho 1 , Yong Nam Choi 3 , 

Hee-ju Lee 3 , Chae Ryong Cho 2 , Hideomi Koinuma 1 and Se-young Jeong 1 * 

1 Cogno-Mechatronics Engineering, Pusan National University, Korea 

2 Nano fusion technology, Pusan National University, Korea 


Many researchers have tried to apply ZnO for hydrogen storage through additional doping and nanostructure 

which increase hydrogen capability[1]. It has been regarded for Zn-O bond center and oxygen vacancy 

as practicable position for hydrogen storage. Co-Co dimer in ZnCoO has been suggested as appropriate 

position for its reversibility, and hydrogen placed in Co-Co dimer mediates ferromagnetic spin ordering by 

Co-H-Co complex[2,3]. In our recent research, we have reported the correlation between hydrogen content 

and ferromagnetism in Co doped ZnO (ZnCoO) and suggested that ZnCoO can be exploited for hydrogen 

storage and the tools for the measurement of hydrogen[4]. In this study, ZnCoO powder was fabricated by 

sol-gel method and annealing process was performed at 300 °C and subsequently 800 °C for removing 

organic compound. Pt was coated on ZnCoO powder as hydrogen catalyst. The hydrogen absorption and 

change in structure are characterized by the press composition and temperature (PCT) system and neutron 

diffraction, in-situ. We investigate the correlation between hydrogen contents and magnetism in ZnCoO and 

discuss its applicability for hydrogen storage. We also show the hydrogen contents in ZnCoO depending on 

the Pt layer and the spillover effect between Pt layer and ZnCoO nanocrystal. 

[1] Q. Wan et al., Appl. Phys. Lett. 84, 124 (2004). [2] S. Lee et al., Appl. Phys. Lett. 94, 212507 

(2009). [3] Y. C. Cho et al., Appl. Phys. Lett. 95, 172514 (2009). [4] S. Lee et al., J. Appl. Phys. (in 

press, 2012). 

QL19 

Ferromagnetism in Co-doped TiO2 films probed by low-energy muon 

spin rotation 

Hassan Saadaoui 1 *, Jiabao Yi 2 , Zaher Salman 1 , Thomas Prokscha 1 and Elvezio 

Morenzoni 1 

1 

Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, 5232 Villigen PSI, 

Switzerland 

2 

School of Materials Science and Engineering, University of New South Wales, 

Kensington, NSW, 2052, Australia 

Ferromagnetic semiconductors have been widely studied recently for potential 

applications in spintronics. In this experiment, we probe the magnetism in Co-doped 

TiO 2 ferromagnetic semiconducting films using Low-energy muon spin rotation (LEμSR). 

This technique is very powerful to probe the magnetic properties of thin films 

and interfaces on a nanometer length scale. We investigated Co-doped (5%) TiO 2-δ 

films grown in different oxygen pressures. We find the internal magnetism in these 

films to be strongly dependent on the oxygen pressure during growth. The oxygen 

vacancies, modified by pressure, act as electron donors and alter the electron density. 

As the pressure increases, the magnetic volume fraction is strongly reduced. In this 

work, we present the temperature, magnetic field and depth dependence of the internal 

magnetism, and discuss its origin. 

QL20 

Structural and magnetic changes induced by high energy ball milling 

of CdFe 2O 4 oxide 

Justice Msomi and Ta Nhlapo 

School of Chemistry and Physics, University of KwaZulu-Natal, South Africa 

Bulk CdFe 2O 4 ferrite nanoparticles have been synthesized by solid state reaction. 

The fine powders of CdFe 2O 4 oxide were produced by high energy ball milling. The 

structural and magnetic changes induced by high energy ball milling are investigated. 

The oxides have been characterised by XRD, Mossbauer spectroscopy and VSM 

measurements. A general decrease in lattice constant with increasing milling time is 

observed. The Mossbauer spectra indicate paramagnetic spin state in all the samples. 

Magnetization increases with reduction in particle size. This can be explained by the 

redistribution of Cd ions in both tetrahedral (A) and octahedral (B) sites. The coercive 

field of the milled CdFe 2O 4 oxide are highly sensitive to temperature compared to that 

of the bulk compound. An increase in coercive field for 50 hours milled oxide from 

about 9 Oe at 300 K to 520 Oe at 10 K has been observed. A smaller increase from 

9 Oe at 300 K to 200 Oe at 10 K occurs in the coercive field of the bulk oxide. The 

variation of magnetization as a function of measuring temperature is also presented. 

An anomalous variation of field cooled magnetization as a function of temperature has 

been observed. 

QL21 

QM01 

QM02 


Room temperature ferromagnetism in Zn 1-xNi xS diluted magnetic 

semiconducting nanocrystalline thin films 

M A El-hagary 1 *, Soltan Soltan 2 , M Emam-ismail 1 and S Althoyaib 1 

1 Physics Department, Qassim University, Saudi Arabia 

2 Physics Department, Helwan University, Helwan, Cairo, Egypt, Egypt 

We have investigated the magnetic properties of Ni doped Zn 1-xNi xS diluted magnetic 

semiconducting nanocrystalline thin films for different doping concentrations (0.005 

≤ x ≤ 0.2) synthesized by electron beam evaporation technique. X-ray diffraction 

patterns confirm the existence of single phase nature in all the Ni doped Zn 1-xNi xS 

samples with cubic zinc blend type structure. Evidence of nanocrystalline nature of 

the films was observed from the investigation of surface morphology using scanning 

electron microscopy and atomic force microscopy. Magnetic domains were observed 

by using magnetic force microscopy at room temperature indicating the existence 

of ferromagnetism over the film surface. The temperature and field dependent 

magnetization measurements by using superconducting quantum interface device 

showed ferromagnetic behavior between room and low temperatures (5 K) with a Tc 

at or above room temperature for the nanostructure samples with 0.1 ≤ x ≤ 0.2. The 

saturation magnetization for Zn 1-xNi xS system is found to increase with the dopant 

concentration (x). The exchange interaction between local spin polarized electrons (Ni 

ions) and conductive electrons according to RKKY mechanism, rather than from the 

Ni oxide impurities, is proposed to be the possible mechanism for ferromagnetism. 

Extraordinary hall measurements of Co/Ni multilayers 

Chih-yung Chen 1 , James C Eckert 1 , Natalia Fear 1 , Sheena K. K. Patel 1 , Richard 

Sayanagi 1 , Patricia D Sparks 1 , E Shipton 2 and Eric E Fullerton 2 

1 Physics, Harvey Mudd College, USA 

2 University of California, San Diego, USA 

Interest in Co/Ni multilayers is driven by their unusual magnetic properties. They 

exhibit perpendicular magnetic anisotropy, relatively low magnetic damping and 

unusual magneto-transport characteristics making them well suited for spintronic 

devices. To understand their magnetic and magneto-transport properties we measured 

the temperature dependence of the Hall effect for a series of sputtered Ni/Co films: 

SiO2/Ta(40A)/Pd(40A)/[Co(2A)/Ni(Y)]x10/Ta(40A)), with Ni thicknesses from Y=2- 

14 A. Because the signs, and the temperature dependence, of the extraordinary Hall 

effects (EHE) differ for Co and Ni, the behavior for the multilayers is complex. At 

room temperature the sign of the EHE changes as the Ni thickness increases from 4 to 

5A. For Y=4A, the sign of the EHE is temperature dependent, going to zero near 220K 

and changing sign for lower temperatures. The magnitude of the EHE increases with 

increasing temperature for Y6A. We used the EHE to measure the magnetization properties finding a decrease 

in the coercive field for increasing Y. For Y



QM03 

Cross over from anisotropic magnetoresistance to magnon 

magnetoresistance in PLD grown permalloy nanowires 

Vineeth Mohanan Parakkat and Anil P. S Kumar 

Physics, Indian Institute of Science, India 

We are able to observe and distinguish Anisotropic-Magnetoresistance(AMR) and 

Magnon Magnetoresistance(MMR) [1] contributions clearly in Permalloy nanowires by 

varying their width thereby tuning their shape anisotropy. Nanowires of thickness 20nm 

and varying widths down to 160nm were prepared by e-beam lithography and Pulsed 

Laser Deposition. A linear non-saturating longitudinal MR observed in high field regime 

for NiFe nanowires could never be explained using AMR but only MMR can account 

for it. MMR follows as ρ=α(M/Ms)B, where M is magnetization along the easy axis, 

Ms saturation magnetization, B magnetic field applied along the easy axis, α=(dρ/dB) is 

the slope of ρ(B) at magnetic saturation. A cross over in magnetoresistance at low field 

from AMR-dominant to MMR-dominant one was observed as wire width reduces since 

the AMR value is getting reduced from 1.2% for 650nm wide wire to 0.26% for 160nm, 

however the contributions from the electron-magnon interactions still persist. At 280nm 

itself the AMR contribution to the longitudinal MR has substantially reduced so that 

only magnon effect is visible. The MMR proves to be an excellent way of determining 

M/Ms, understanding the magnetization reversal mechanisms in nanostructures, domain 

wall dynamics and also fundamental problems like electron magnon interactions. 

1. A. P. Mihai et al Phy. Rev. B 77, 060401 (2008). 

QM04 

Investigation of magnetic anisotropy of ferromagnetic GaMnAs film 

by planar Hall effect 

Jaehyuk Won 1 , Jinsik Shin 1 , Yoonjung Gwon 1 , Hyehyeon Byeon 1 , Sangyeop Lee 1 , 

Sanghoon Lee 1 *, X. Liu 2 and J. K. Furdyna 2 



Magnetic anisotropy properties of the GaMnAs ferromagnetic film have been 

investigated by using planar Hall effect measurements. The field scan of the planar 

Hall resistance (PHR) showed a two-step switching behavior indicating a strong cubic 

anisotropy along the directions. The difference in the behavior of the PHR for the 

two applied field directions between the [11 0] and the [110] was understood via wellknown 

uniaxial anisotropy along the [110] direction. In addition to such known effects, 

we also found the presence of asymmetry for the field directions between the [010] and 

the [100] directions. This new asymmetry phenomenon was explained by introducing an 

additional uniaxial anisotropy field H U2 along the [100] and the [100] directions, which 

coincides with the two directions of cubic anisotropy. The values of the anisotropy fields, 

cubic (H c), first uniaxial (H U1), and second uniaxial (H U2), were obtained by analyzing 

the angle dependence of the PHR. Although the value of is small, its effect is clearly 

observed at high temperature above 25 K, where the transition of magnetization occurred 

before the field direction is reversed during the magnetization reversal process. 

PACS number: 73.50.-h; 75.50.Pp; 75.30.Gw 

Keywords: Ferromagnetic semiconductor, Magnetic anisotropy, Planar Hall effect 

QM05 

A crossover between magnetic vortex state and strip domains in 

electrodeposited nanogranular nickel films 

Alexander Sergeevich Samardak 1 *, Ekaterina Sukovatitsina 1 , Alexey Ognev 1 , Ludmila 

Chebotkevich 1 , S. M. Janjan 2 and Farzad Nasirpouri 2 

1 

School of Natural Sciences, Far Eastern Federal University, Institute of Automation 

and Control Processes FEBRAS, Russia 

2 

Department of Materials Engineering, Sahand University of Technology, Iran 

We have investigated the change of magnetization mode of nanogranular nickel films 

electrodeposited on silicon. The electrodeposition of nickel at a distinct potential starts with the 

formation of isolated nanogranules with size of 130÷190 nm which subsequently tend to coalesce 

forming a continuous nanogranular film. Assuming nickel nanogranules as oblate spheroids 

and calculating the critical size for single domain state, we find that the nickel nanogranules are 

magnetized under vortex ground state. Micromagnetic simulations calculated for this isolated 

nanogranules and MFM images confirm the magnetic vortex states for electrodeposited nickel 

nanogranules. Upon the nanogranules joining each other, coercivity increases due to the reduction 

of intergranular space and strengthening of magnetostatic interaction. Further growth leads to the 

formation of continuous nanogranular film which is associated with decrease in coercivity and 

rotation of the easy axis of magnetization to in- plane mode which is characterized by the domain 

wall displacement and strip-like multidomain pattern. The crossover between vortex ground state 

and multidomain magnetic pattern leads to the significant decrease in coercive force. Continuous 

nickel films electrodeposited on silicon have anisotropic magnetoresistance the value of which 

increases as the thickness and, appropriately, uniformity of film is increased. 


QM06 

Non-linear susceptibility of nanogranular FeAg films at the verge of 

superferromagnetism 

D. Alba Venero 1 , L. Fernandez Barquin 1 *, S. N. Kaul 2 , J Alonso 3 and M. L. Fdezgubieda 

3 

1 

CITIMAC, Universidad de Cantabria, Santander 39005, Spain., Spain 

2 

School of Physics and Centre for Nanotechnology, University of Hyderabad, 

Hyderabad - 500046, India, India 

3 

Electricidad y Electronica, Universidad del Pais Vasco, Bilbao 48080, Spain, Spain 

A detailed magnetization study of Fe xAg 100-x films, comprising nanoparticles (3 nm) of Fe embedded in a Ag 

matrix, has recently revealed [1] a crossover from superspin glass state to superferromagnetic state at x?30. This 

changeover is presumably caused by an interplay between the direct exchange, dipolar and RKKY interactions 

operating between the particle magnetic moments. In order to gain further insight into the nature of inter-particle 

interactions and their role, first five harmonics χ1- χ5 of the ac magnetic response were measured at several 

frequencies and magnetic fields over the temperature range 5-300 K on DC-sputtered Fe xAg 100-x (x = 25, 35, 

below and above the percolation threshold, respectively) 100 nm thick films. Susceptibilities χ1- χ5 measured 

in the absence of the superposed dc magnetic field, Hdc, exhibit features that are characteristic of a spin glass 

and a ferromagnet in x = 25, 35. The ferromagnetic fingerprints in the temperature variations of the linear and 

nonlinear susceptibilities become all the more apparent when Hdc is applied. The data are analyzed on the same 

lines as those in the previous works on magnetically disordered CMR manganites [2, 3] and LiNiO insulators [4]. 

[1] J. Alonso et al., Phys. Rev. B 82, 54406 (2010). [2] Y. Bitla and S. N. Kaul, EuroPhys. Lett. 96, 

37012 (2011). [3] L. Fernandez Barquin and R. Garcia Calderon, J. Phys.: Conf. Ser. 17, 87 (2005). 

[4] A. Bajpai and A. Banerjee, Phys. Rev. B 62, 8996 (2000). 

QM07 

Dynamics of Ni-Fe elliptical dot arrays based on CPW-FMR 

measurements 

Yasushi Endo, Naomi Skashita*, Yutaka Shimada and Masahiro Yamaguchi 

Graduate School of Engineering, Tohoku University, Japan 

The dynamics of nanomagnets have been studied intensively for high-frequency 

applications in spintronic devices. The dynamics closely correlate with the damping 

constant α which determines the strength of damping torque in nanomagnets. α has 

been evaluated by exciting ferromagnetic resonance (FMR) in nanomagnets using 

microwave cavities and coplanar waveguides (CPWs). Advantages of CPW-FMR 

measurements are a wide range of radio frequencies and external field intensity and 

micron-scale samples. Herein to clarify the dynamics of nanomagnets, we employed 

FMR measurements with CPW to evaluate α in 50-nm-thick Ni-Fe elliptical dot 

arrays. Effective in-plane anisotropy field Hk,eff increases markedly as the dot size 

decreases, which may be attributed to enhanced magnetostatic energy. Eeffective 

saturation magnetization 4πMs,eff decreases slightly as the dot size decreases because 

the demagnetization field coefficient changes as the dot size decreases. Additionally, α 

increases monotonically from 0.01 to 0.02 as the dot size decreases in a 500 Oe external 

magnetic field applied in the longitudinal axial direction of the dots. Their values are 

higher than that of the Ni-Fe film (α= 0.009) likely because the inhomogeneity of the 

demagnetization field distribution near dot edges. Therefore, these results propose that 

CPW-FMR measurements can evaluate the dynamics of nanomagnets in detail. 

QM08 

Structure and magnetic properties of SiO 2(Co) granular film on GaAs substrate. 

Victor Ukleev 1 *, Natalya Grigoryeva 2 , Ekaterina Dyadkina 1 , Alexei Vorobiev 3 , Dieter Lott 4 , 

Leonid Lutsev 5 , Alexandr Stognij 6 , Dirk Menzel 7 , Nicolay Novitskiy 6 and Sergei Grigoriev 1 

1 Petersburg Nuclear Physics Institute, Russia 

2 Saint-Petersburg State University, Russia 

3 European Synchrotron Radiation Facility, France 

4 Helmholtz-Zentrum Geesthacht, Germany 

5 Ioffe Physical-Technical Institute, Russia 

6 Scientific and Practical Materials Research Centre of NAS of Belarus, Belarus 

7 Institut fur Physik der Kondensierten Materie, TU Braunschweig, Germany 

The effect of giant injection magnetoresistance (GIMR) was recently observed in a granular SiO 2/ 

(54 - 75 at.% Co) film on a semiconductor GaAs substrate in a temperature range near T = 300 K. The 

magnetoresistance reaches the value of 10000% in the magnetic field of 1.9 T and at the voltage of 90 

V [1]. The grazing-incidence small-angle X-ray scattering (GISAXS) data indicated the layer of lower 

concentration of cobalt particles at the granular film/semiconducter interface if compared to the SiO 2(Co) 

granular film itself. The thickness of this interface layer is about 70 A [2]. The polarized neutron reflectometry 

confirms the existence of the additional layer on the granular film/substrate interface. The temperature 

dependence of the magnetization M(T) shows the presence of two types of magnetic nanoparticles with 

different blocking temperatures and magnetization dynamics. The hysteresis curve of the magnetization 

demonstrates two-loop structure in region of the fields 0 - 80 mT and 80 - 200 mT. Data obtained by 

polarized neutron reflectometry, GISAXS and SQUID measurements are well correlated with each other 

and give the possibility to develop the GIMR effect theory paying attention to the interface features. 

[1] L.V. Lutsev, A.I. Stognij, and N.N. Novitskii, Phys. Rev. B, 184423 (2009). [2] N. Grigor'eva, A. Vorob'ev, V. 

Ukleev, E. Dyad'kina, L. Lutsev, A. Stognij, N. Novitskii, and S. Grigor'ev, JETP Letters, 92:767 - 773, 2010.

QM09 

Magnetic properties and structure of electrodeposited nickel on thin 

niobium film 

Huei-ying Ho 1 *, Wei-yan Lin 1 , Shih-jia Chen 1 , Hong-wen Cheng 1 and Yung Liou 2 

1 Department of Science Education, National Taipei University of Education, Taiwan 


Cyclic voltammetry, chronopotentiometry, atomic force microscope, magneto-optical 

Kerr effect, and X-ray diffraction were used to investigate the magnetic property and 

structure of thin Ni films electrodepositing onto a 100 nm Nb. Constant-current method 

was used to grow the Ni films in this study. During the reduction process of Ni, a small 

amount of β-Ni(OH) 2 is formed; it becomes intense when the applied potential is more 

cathodic. The average size of the Ni grains grows and the coercivity of the Ni film 

decreases during the steady-state depositing process. The preferred orientations of the 

electrodeposited Ni film are fcc-(111) and fcc-(200), the easy axis of the magnetization 

of it is in the in-plane direction, however. This may due to the formation of the 

β-Ni(OH) 2. The effects of current density on the magnetism and structure were also 

studied. The high current density does not make any significant change in the magnetic 

property if the current density is higher than 5.2 mA/cm 2 . This may due to the intense 

hydrogen evolution reaction during the high current density deposition. These results 

could be the foundation of further research in the hydrogen energy area. 

QM10 

Characterization of epitaxial EuS(111) thin films on BaF2(111) and 

SrF2(111) substrates grown by molecular beam epitaxy 

Shinya Senba 1 *, Naoki Matsumoto 2 , Mitsuhiro Jomura 2 , Hironori Asada 2 , Yasuhiro 

Fukuma 3 , Tsuyoshi Koyanagi 2 and Kengo Kishimoto 2 

1 Ube National College of Technology, Japan 

2 Graduate School of Science and Engineering, Yamaguchi University, Japan 

3 Faculty of Computer Science and Systems Engineering, Kyushu Institute of 


A ferromagnetic insulating EuS thin film has received considerable attentions in fundamental studies of spin 

injection devices because of its very high spin filter efficiency[1]. It has been reported that EuS thin films 

on Si(100) and GaAs(100) substrates become insulating at a growth temperature(Ts) of 300°C and above, 

and the resistivity of that decreases with decreasing Ts due to the sulfur deficiency[2]. In this study, we have 

successfully grown EuS(111) epitaxial films on BaF2(111) and SrF2(111) substrates using molecular beam 

epitaxy at Ts=100~500°C. Pole figures of x-ray diffraction indicate a high degree of in-plane orientation, and 

all of the samples show very high resistivity. The arithmetic mean deviation of the surface for 10 nm-thick 

EuS films on BaF2(111) and SrF2(111) substrates measured by AFM are 0.122 and 0.092 nm, respectively. 

The Curie temperature of EuS films increases up to ~16 K with increasing Ts. In order to achieve an antiparallel 

state between two ferromagnetic layers in spin injection devices, we try to manipulate the coercive 

force by Te doping. The obtained coercive force of Te-doped film (110 Oe) is large compared with that of 

undoped one (20 Oe).Optical properties such as a magnetic circular dichroism are also presented. 

[1] P. LeClair et al., Appl. Phys. Lett. 80, 625 (2002). [2] I. J. Guilaran et al., Phys. Rev. B 68, 

144424 (2003). 

QM11 

The cation distribution and electrical hopping in Fe 3-xCo xO 4 (0



QM15 

Parallel spin wave resonance in exchange-biased NiFe/FeMn/NiFe 

trilayers 

Fernando Pelegrini 1 *, Valberto Pedruzi Nascimento 2 , Armando Biondo 2 , Edson 

Caetano Passamani 2 and Elisa Baggio-saitovitch 3 

1 Instituto de Fisica, Universidade Federal de Goias, Brazil 

2 Departamento de Fisica, Universidade Federal do Espirito Santo, Brazil 


The Ferromagnetic Resonance (FMR) technique was used to study the magnetic properties of asymmetrical 

NiFe 30nmFeMn 15nmNiFe 10nm trilayers magnetron sputtered under working pressures of 2, 5 and 10 mTorr, in the 

presence of a 460 Oe magnetic field to set the unidirectional anisotropy. The FMR experiments were done at 

room temperature using a commercial spectrometer operating with microwave frequencies of 9.79 and 34.0 

GHz, swept static magnetic field and the usual detection techniques. At a microwave frequency of 34.0 GHz, 

the parallel FMR spectra reveal that spin wave and uniform resonance modes are excited by the microwave 

field. The study of the in-plane angular dependences of the resonance fields reveals for both modes the effect 

of the unidirectional anisotropy. The dependences of the absorption fields on cosθ, where θ is the field angle 

with respect to the anisotropy axis, give for the spin wave and uniform modes of the sample produced under 

the pressure of 2 mTorr the anisotropy fields of 66 and 37 Oe, respectively. The parallel FMR results and spin 

wave resonance theory imply for this sample the exchange constant of 0.92 x 10-6 erg/cm. This result agrees 

with perpendicular FMR measurements at a microwave frequency of 9.79 GHz. 

[1] V. P. Nascimento, E. Baggio-Saitovitch, F. Pelegrini, L. C. Figueiredo, A. Biondo and E. C. 

Passamani, J. Appl. Phys. 99 (2006) 08C108. [2] W. Stoeklein, S. S. Parkin and J. C. Scott, Phys. 

Rev. B 38 (1988) 6847. [3] M. Nisenoff and R. W. Terhune, J. Appl. Phys. 36 (1964) 733. 

QM16 

Studies on local structures and magnetism at buried Fe/ Fe3O4 interfaces using synchrotron-radiation Mössbauer spectroscopy 

Ko Mibu 1 *, Hideto Yanagihara 2 , Takaya Mitsui 3 , Ryo Masuda 3 , Shiori Hori 1 , Atsushi 

Murata 1 , Masaaki Tanaka 1 , Kazuya Suzuki 2 , Eiji Kita 2 and Makoto Seto 4 

1 

Graduate School of Engineering, Nagoya Institute of Technology, Japan 

2 

Institute of Applied Physics, University of Tsukuba, Japan 

3 

Japan Atomic Energy Agency, Japan 

4 

Research Reactor Institute, Kyoto University, Japan 

Strong antiparallel magnetic coupling was found recently in Fe/ Fe 3O 4 bilayers [1], 

and attention has been paid as a new and noble-metal-free “synthetic antiferromagnet” 

for magnetic recording devices. In order to clarify the mechanism of this interfacial 

magnetic coupling, it is important to elucidate the local crystallographic structure 

and magnetism at the buried interface experimentally. Mössbauer spectroscopy is a 

useful method to obtain such information through absorption spectra of gamma-rays 

(or X-rays) by the constituent Fe nuclei. In this presentation, we report the results 

we have obtained using recently developed synchrotron-radiation-based Mössbauer 

spectroscopy with a nuclear Bragg monochromator at BL11XU, SPring-8 [2]. The 

structures and magnetism at the buried Fe/ Fe 3O 4 interface are discussed on the basis of 

the obtained spectra. 

[1] H. Yanagihara et al., Appl. Phys. Express 1 (2008) 111303. [2] T. Mitsui et al., J. Synchrotron 

Radiation 19 (2012), in press. 

QM17 

Dependence of in-plane magnetic anisotropy of Au/Co/Au 

heterostructures on thickness of Co-component layer: An FMR study 

Leszek Gladczuk, Pavlo Aleshkevych and Piotr Przysłupski 

Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, PL02-668 

Warsaw, Poland., Poland 

Recently, there was a lot of interest in magnetic tunnel junctions built from electrodes 

characterized by in-plane magnetic anisotropy. In the present study; ultrathin Mo/Au/ 

Co/Au heterostructures where the cobalt layer is of the wedge shape (i.e. with thickness 

gradually changing along the sample) were grown on a sapphire substrate by molecular 

beam epitaxy. Room temperature ferromagnetic resonance (FMR) measurements 

were used to evaluate the resonance field as a function of (i) the in-plane and the outof-plane 

orientation of external magnetic field and of (ii) the cobalt layer thickness. 

The experiments demonstrates an interesting effect of enhancement of the in-plane 

anisotropy for heterostructures with wedge-shaped Co layer. This finding provides a 

method to modify the magnetic anisotropy, which can be of a great importance for the 

application in magnetic tunneling junctions. A comparison of the obtained results with 

earlier data on Co anisotropy will be presented. 


QM18 

Depth dependent chemical and magnetic information of CoFeB/ 

MgO multilayered thin films studied by x-ray and polarized neutron 

reflectometry 

Ki Yeon Kim 1 *, Il Jae Shin 2 , Byoung Chul Min 2 , Hyeok Cheol Choi 3 , Chun Yeol 

You 3 , Jeong Soo Lee 1 , Surendra Singh 4 , M. R. Fitzsimmons 4 and Sungkyun Park 5 

1 

Neutron Science Division, Korea Atomic Energy Research Institute, Korea 

2 

Center for Spintronics Research, Korea Institute of Science and Technology, Korea 

3 

Department of Physics, Inha University, Korea 

4 


5 

Department of Physics, Pusan National Laboratory, Korea 

Magnetic Tunnel Junctions (MTJs), consisting of a crystalline MgO barrier sandwiched by amorphous CoFeB 

layers, have received much attention owing to novel magnetic and transport properties such as perpendicular 

magnetic anisotropy and large tunneling magneto-resistance at room temperature [1-2]. With a combined study 

of x-ray (XRR) and polarized neutron reflectometry (PNR), depth-dependent chemical and magnetic profiles 

in Co 40Fe 40B 20/MgO multilayered thin films were investigated. The annealing was done at 400°C for half an 

hour in an applied field of 4 kOe after sample growth. In addition to XRR and PNR, structure characterization 

was also conducted using high-angle theta/2theta x-ray diffraction, and high resolution tunneling electron 

microscopy (HR-XTEM); the magnetic property was studied using vibrating sample magnetometer. The 

boron diffusion and magnetic moment around both CoFeB/MgO interfaces will be discussed in detail. 

[1] S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma, H. D. Gan, M. Endo, S. Kanai, H. Hasegawa, J. Hayakawa, 

F. Matsukura, and H. Ohno, Nature Mater. 9, 721 (2010). [2] D. D. Djayaprawira, K. Tsunekawa, M. Nagai, H. 

Maehara, S. Yamagata, N. Watanabe, S. Yuasa, Y. Suzuki, and K. Ando, Appl. Phys. Lett. 86, 092502 (2005). 

QM19 

Depth-resolved rotational hysteresis of exchange-coupled Fe/Cr 

multilayers 

Tatyana Guryeva, Kai Schlage, Hans-christian Wille and Ralf Roehlsberger 

HASYLAB, Deutsches Elektronen-Synchrotron (DESY), Germany 

QM20 

WITHDRAWN 

Magnetization reversal behavior in exchange-coupled NiFe/FeMn/ 

CoFe trilayers: vectorial MOKE & PNR study 

Ki Yeon Kim 1 *, Ji Wan Kim 2 , Hyeok Cheol Choi 3 , Anke Teichert 4 , Chun Yeol You 3 , 

Sungkyun Park 5 , Sung Chul Shin 2 and Jeong Soo Lee 1 

1 Neutron Science Division, Korea Atomic Energy Research Institute, Korea 

2 Department of Physics and Center for Nanospinics of Spintronic Materials, Korea 

Advanced Institute of Science and Technology, Korea 


4 Helmholtz Zentrum Berlin fur Materialien und Energie, Germany 

5 Department of Physics, Pusan National Laboratory, Korea 

With a combination of vector magneto-optic Kerr effect (MOKE) magnetometry and polarized neutron 

reflectometry(PNR), the detailed magnetization reversal mechanism of the exchange-biased Py(30-nm)/ 

FeMn[t_AF=0-30nm]/CoFe(30-nm) trilayers was studied.[1] We found that Py/FeMn(15-nm) and FeMn/ 

CoFe bilayers show completely different magnetization reversal modes, whereas they become very similar 

to each other in the corresponding Py/FeMn/CoFe trilayers. This is convincing evidence that the 15nm 

FeMn layer mediates the magnetization reversal behaviors of Py and CoFe layers through interlayer 

exchange bias coupling. Furthermore, magnetization reversal of Py and CoFe layers are decoupled for t_ 

AF=30 nm, indicating that both Py and CoFe layers separated by an intermediate FeMn layer are exchangecoupled 

within 30 nm distance. This is in reasonable agreement with the theoretically predicted domain-wall 

width such as 28 nm for the polycrystalline FeMn/Co bilayers and 50 nm for the perfect Fe 50Mn 50 crystal. 

[1]Ki-Yeon Kim, Ji-Wan Kim, Hyeok-Cheol Choi, A. Teichert, Chun-Yeol You, Sungkyun Park, Sung- 

Chul Shin, and Jeong-Soo Lee, Phys. Rev. B. 84,144410 (2011).

QM21 

Uniaxial magnetic anisotropy of La 0.7Sr 0.3MnO 3 film grown on stepterrace 

surface SrTiO 3 (100) substrate 

Byeong-geon Kim, Sanghoon Ki and Joonghoe Dho* 

Kyungpook National University, Korea 

In this work, we used the step-terrace surface STO (100) substrates to control the spin 

direction of the La 0.7Sr 0.3MnO 3 (LSMO) film in the atomic level. The shape magnetic 

anisotropy in the nano scale was induced by using step-terrace surface STO (100) 

substrates with small vicinal angle of 0.1 degree. Atomically flat STO substrate was 

prepared by annealing after etching by HCL (hydrochloric acid), and the surface 

morphology of the STO substrate with molecular step-and-terrace was observed by 

atomic force microscopy. Here, we simultaneously deposited two La 0.7Sr 0.3MnO 3 films 

on the processed and unprocessed STO substrates by using pulsed laser deposition. 

The direction dependence of magnetic hysteresis within the film plane was investigated 

by using SMOKE (Surface Magneto-Optical Kerr Effect) system. The magnetic 

hysteresis loops of the LSMO film on the unprocessed STO substrate showed weak 

direction dependence within the plane, while those on the step-terrace surface STO did 

a significant uniaxial magnetic anisotropy along the longitudinal direction of the stepterrace 

of the STO substrate. 

QM22 

The effect of compositional ratio on the magnetocaloric effect 

Ho-sup Kim 1 , Sang-soo Oh 1 , Kiran Shinde 1 , Seung-kyu Baik 1 , Kook-chae Chung 2 and 

Bhavesh Bharat Sinha 2 

1 Korea Electrotechnology Research Institute, Korea 

2 Korea Institute of Materials Science, Korea 

Film type Ni-Mn-Ga alloys were prepared using co-evaporation method in order to 

investigate the effect of compositional ratio on magnetocaloric effect (MCE). In the 

deposition process on the metal substrate, Ni was evaporated by an induction heating, 

and Mn and Ga were evaporated by a resistive heating. The deposition rate of each 

element was measured by Quartz Crystal Microbalance and the rate was controlled 

up to 0.1 mm / hour to get a thick Ni-Mn-Ga film. Three crucibles of Ni, Mn, and Ga 

were arranged triangularly to form the composition gradient of Ni-Mn-Ga film on the 

surface of whole substrate. Long tape samples with different composition of Ni, Mn, 

and Ga along the length were prepared. The magnetic property of prepared sample at 

around transition temperature was continuously evaluated by a reel to reel Hall probe 

measurement system with a temperature controller. The Hall probe signal is related to 

the relative value of MCE so that the optimal composition ratio could be obtained by 

analyzing it. The section which exhibited the highest value in Hall probe measurement 

was cut and analyzed by XRD and followed by MCE measurement using PPMS 

equipment. Detailed experimental results will be reported in the presentation. 

1. V. Recarte et al.,Appl. Phys. Lett., 95, 141908, 2009. 2. Yuepeng Zhang et al.,Smart Mater. Struct., 

18 , 025019, 2009. 3. V A Chernenko et al.,J. Phys.: Condens. Matter ,17,5215-5224, 2005. 

QM23 

Magnetocaloric effect in Ni doped Zn ferrite nanoparticles grown by 

the combustion method 

Kyungdong Lee, Rahul Chandrakant Kambale and Namjung Hur* 

Department of Physics, Inha university, Korea 

We studied the magnetocaloric effect (MCE) in two different compositions of Ni- 

Zn ferrite nanoparticles (Ni xZn 1-xFe 2O 4, x=0.2 and 0.3) which were prepared by 

the combustion method. From the temperature and the magnetic field dependent 

magnetization curves, the magnetic entropy changes (ΔS) and the adiabatic temperature 

changes (ΔT) were evaluated. Magnetocaloric effect in these nanoparticles is compared 

to that in bulk system with the same compositions to study the effects of grain size. 

Although the values of ΔS and ΔT at 2 T magnetic fields in these nanoparticles are 

lower than the values in the bulk one, wider effect transition windows were observed 

in nanoparticle systems. As the domain size of Ni-Zn ferrite nanoparticles affects the 

temperature and magnetic field dependence of magnetization, the maximum ΔS and ΔT 

are also influenced by the grain size around the magnetic transition temperature (TC). 

Therefore, the field dependence of ΔT at TC, which can be analyzed by the mean field 

approximation denoted by the exponential p, was found to be different from the typical 

one. 

QM24 

QM25 

QM26 


Interlayer interaction In ReCoPO (La, Nd and Sm): 31P NMR Study 

M Majumder 1 , K Ghoshray 1 *, A Ghoshray 1 , A Pal 2 and V. P. S Awana 2 

1 ECMP Division, Saha Institute of Nuclear Physics, Kolkata, India 

2 QPA Division, National Physical Laboratory (CSIR) Dr. K.S. Krishnan Marg, New 

Delhi-110012, India 

31P NMR result is presented in Co based non-superconducting members of pnictides 

family revealing the importance of the interlayer interaction, a key factor that 

determines the ground state. In ReCoPO (Re = rare earth) series, La and Ce show 

only PM → FM transition, whereas Nd and Sm show successive PM → FM → AFM 

transition with varying degree of TC and TN. 31P NMR spectrum in polycrystalline 

La, Nd and SmCoPO respectively corresponds to a powder pattern for a spin 1/2 

nucleus with axially symmetric local magnetic field showing varying degree of shift 

parameters. In particular, Nd and Sm compound show large temperature dependent 

shift anisotropy with similar magnitude of Kiso and Kax. However, relaxation rate (1/ 

T1T) in Sm is atleast two orders of magnitude higher than that observed in other two 

compounds. Our earlier 31P and 139La NMR [1] measurements in LaCoPO (quasi 2D 

Fermi surface) reveal dominant 2D spin fluctuation of 3d electrons in PM state with 

non negligible 3D part and in the FM state spin fluctuation is 3D in nature. Whereas, 

in SmCoPO the present result is able to distinguish the FM in plane spin-correlations 

from the AFM type out of plane spin-correlations. 

1. M. Majumder, K. Ghoshray, A. Ghoshray, B. Bandyopadhyay, M. Ghosh , Phys. Rev. B 82, 054422 

(2010). 

Jahn-teller distortion and enhancement of curie temperature of Mn 3xNi 

xO 4 films on MgO (001) by molecular beam epitaxy 

Der-sheng Lee 1 , K. M. Kuo 2 and Gung Chern 2 * 

1 Electrical Engineering Department, DA-YEH University , Chunghua, Taiwan 

2 Physics Department and SPIN Research Center, National Chung Cheng 

University,Chia-Yi, Taiwan 

We report on x-ray diffraction, scanning electron micrograph, and magnetization 

measurements vs. external field and temperature of Mn 3-xNi xO 4 (x=0, 0.25, 0.5, 

0.75, 1) films grown on MgO (001) and (011) substrates by molecular beam 

epitaxy. Magnetization vs. temperature measurements reveal that Curie temperature 

increases from 43 K to 103 K as the Ni composition increasing. This increase of Tc 

is qualitatively understood as a result of the decrease of the exchange coupling of the 

cations between B site and B site (JBB). The Jahn-Teller distortion also reduces as the 

Ni composition increasing and the cubic structure is estimated to be recovered as x 

approaches ~ 1.2. The cation distribution in the present films is different from the bulk 

and can be described as [Mn²+1-xMn³+2x/3Ni²+x/3]A[Ni²+2x/3Mn³+2-2x/3]BO 4. 

Anomalous switching of in-plane magnetic anisotropy of Fe and Co 

thin films grown on curved Pt(001) surface 

Wondong Kim 1 *, Chanyong Hwang 1 and Z.-q. Qiu 2 


2 Physics Department, University of California at Berkeley, USA 

We investigated the step-induced magnetic anisotropy of Fe and Co thin films grown 

on the curved Pt(001) surface using Surface Magneto-Optical Kerr Effect(SMOKE) 

and Scanning Tunneling Microscopy(STM). The continuous variation of step density 

of the curved Pt(001 surface are confirmed by STM experiment. From SMOKE 

measurements on both of Fe and Co thin films, we observed the switching of the 

magnetic easy axis from the parallel-to-step direction to the step-normal direction with 

increase of the step-density. We attributed The origin of this anomalous transition to the 

abrupt change in the step structure at high-step density position, which was revealed by 

STM measurements. 


Poster Tuesday



QM27 

Magnetic-field and temperature-dependent relaxation in ferrofluids 

characterized with a high-Tc SQUID-based nuclear magnetic 

resonance spectrometer 

Hong-chang Yang 1 *, Chieh-wen Liu 2 , Shu-hsien Liao 3 , M.j. Chen 1 , K.l. Chen 1 , Hsinhsien 

Chen 3 , Herng-er Horng 3 , L.m. Wang 1 and S.y. Yang 3 

1 Department of physics, National Taiwan University, Taiwan 

2 Department of Physics, National Taiwan University, Taiwan 

3 Institute of Electro-Optical Science and Technology, National Taiwan Normal 

University, Taiwan 

In this work the magnetic-field and temperature dependent spin-lattice relaxation 

rate, 1/T1, and spin-spin relaxation rate, 1/T2, of ferrofluids are characterized using a 

high-Tc SQUID-based magnetometer as the detector. The ferrofluids are consisted of 

detrain-coated Fe 3O 4 dispersed in phosphate buffer saline solution. It was found that 1/ 

T1 measured in a magnetic field of 56.8 mT is significantly higher than 1/T2 measured 

in a magnetic field of 102 μT. We attribute this to the magnetic-field gradients from 

magnetic nanoparticles that accelerate the T1-relaxation more in a high strength of 

magnetic fields than they are in a low strength of magnetic fields. Furthermore, 1/T1 

and 1/T2 decrease when temperature increases. We attribute this to the improved fieldhomogeneity 

seen by protons’ spins under the influence of enhanced Brownian motion 

of magnetic nanoparticles at high temperatures than they are at low temperatures. 

Characterizing the relaxation rates of ferrofluids in low concentration regimes will be 

helpful for their future applications such as the low field MR imaging. 

QM28 

Influence of metal precursor on synthesis and magnetic properties of 

nanocrystalline strontium hexaferrite thin films 

S. M. Masoudpanah, S. A. Seyyed Ebrahimi* and M. Khodaei 

Center of Excellence for Magnetic Materials, University of Tehran, Iran 

The effects of starting metal salts on the structure and magnetic properties of strontium 

hexaferrite thin films synthesized by sol gel process have been investigated. Fourier 

transform infrared and thermal analyses were conducted to determine the chelated 

species and thermal decomposition of the gels, respectively. X-ray diffraction, 

scanning electron microscopy and vibrating sample magnetometery techniques were 

also applied to evaluate the microstructure, composition, crystallite size and magnetic 

properties of the thin films. The results showed the film prepared from nitrate precursor 

offered a single phase strontium hexaferrite with nanocrystalline structure and higher 

saturation magnetization after calcination. However, the films obtained from hydroxide 

and chloride precursors had higher coercivity due to smaller crystallite size. 

QM29 

Planar Hall effects measurements of sensitive magnetization response 

in epitaxial Fe thin films 

Anis Faridah Md Nor 1 *, Tatsuya Matsumoto 2 , Teppei Takashima 2 , Terumitsu Tanaka 2 

and Kimihide Matsuyama 2 

1 Physics Department, University of Malaya, Malaysia 

2 Department of Electronics, ISEE, University of Kyushu, Japan 

The Fe thin film is a promising candidate for future magnetic microwave devices, owing to 

the high ferromagnetic resonance frequency with an order of 10 GHz [1-2]. A high sensitive 

magnetization response is crucial for the low power device operation. In the present study, we 

prepared Fe(100) thin films deposited on MgO(100) substrates using magnetron sputtering 

system and investigate the magnetization process using the planar Hall effect (PHE).The 

PHE measurements were carried out with several Fe thicknesses and temperatures. In the 

PHE measurements, alternating external magnetic fields along vertical easy axis were applied 

with various amplitudes and the sense current was applied along the horizontal easy axis. 

With increase of alternating magnetic field, the PHE voltage increased due to the disposition 

of Fe magnetization from easy axis. When the alternating magnetic field exceed a threshold 

value, the PHE voltage decreased rapidly. The threshold value depend on the thickness of Fe 

film and the PHE voltage decreased with decreasing temperature. These results suggest that 

the magnetization rotates exceeding the hard axis direction and reversible susceptibility can 

be realized. The stochastic aspect of the magnetization process also appears at 10 K. 

[1] E. Schloeman et al., J. Appl. Phys., 63, 3140 (1988). [2] N. Cramer et al., J. Appl. Phys., 87, 

6911 (2000). 


QN01 

Antiferromagnetic order and domains in Sr 3Ir 2O 7 

S. Boseggia 1 , R. Springell 1 , H. C. Walker 2 , A. T. Boothroyd 3 , D. Prabhakaran 3 , D. 

Wermeille 4 , L. Bouchenoire 4 , S. P. Collins 5 and D. F. Mcmorrow 1 

1 Physics and Astronomy, London Centre for Nanotechnology, UCL, United Kingdom 


3 Clarendon Laboratory, University of Oxford, United Kingdom 

4 5XMaS, UK-CRG, European Synchrotron Radiation Facility, France 

5 Diamond Light Source, Didcot, Oxfordshire, United Kingdom 

Resonant scattering at the Ir L2, 3 edge has been used to determine that Sr 3Ir 2O 7 is a 

long-range ordered antiferromagnet below TN~230 K with an ordering wavevector, 

q = (½, ½, 0). The energy resonance at the L3 edge was found to be a factor of ~30 

times larger than that at the L2. This remarkable effect has been seen in the single 

layer compound Sr 2IrO 4 and has been linked to the observation of a Jeff= 1/2 spin-orbit 

insulator. Our result shows that despite the modified electronic structure of the bilayer 

compound, caused by the larger bandwidth, the effect of strong spin-orbit coupling 

on the resonant magnetic scattering persists. Using the programme SARAh, we have 

determined that the magnetic order consists of two domains with propagation vectors 

k1 = (½, ½, 0) and k2 = (½,-½, 0), respectively. A raster measurement of a focussed 

x-ray beam across the surface of the sample yielded images of domains of the order 

of 100 μm size, with odd and even l components, respectively. Fully relativistic, 

monoelectronic calculations (FDMNES) have been employed to calculate the relative 

intensities of the L2, 3 edge resonances, comparing the effects of including spin-orbit 

coupling and the Hubbard, U, term. 

QN02 

High frequency permeability of Fe-Co and Co granular composite 

materials 

Teruhiro Kasagi 1 *, Aiko Tsurunaga 2 , Takanori Tsutaoka 2 and Kenichi Hatakeyama 3 

1 Tokuyama College of Technology, Japan 

2 Graduate School of Education, Hiroshima University, Japan 

3 Graduate School of Engineering, University of Hyogo, Japan 

Relative complex permeability and permittivity spectra of Fe 50Co 50 (Permendur) 

and Co granular composite materials have been studied in the microwave frequency 

range up to 18 GHz. Particles were heat-treated in air using an electric furnace 

in order to suppress the eddy current effect in the composite structure containing 

percolated particles. Composite materials were prepared by mixing these particles 

with Polyphenylene sulfide resin. The 78 vol.% Fe 50Co 50 granular composite has 

the larger relative permeability value than that of the 79 vol.% Co composite at 100 

MHz. The negative frequency dispersion of permeability was observed above 7 and 

8 GHz for Fe 50Co 50 and Co composites, respectively. The dc magnetic field effect on 

the permeability spectra revealed that the permeability dispersion of Co composites in 

the microwave range is mainly attributed to the gyromagnetic resonance. The relative 

permittivity spectra of 78 vol.% Fe 50Co 50 and 79 vol.% Co composites show the 

insulating property up to several GHz; the permittivity value increases with increasing 

particle content in both composites. 

QN03 

Magnetic carbonyl iron suspension with nanoclay additive and its 

magnetorheological properties 

Cheng Hai Hong, Ying Dan Liu and Hyoung Jin Choi* 

Department of Polymer Science and Engineering, Inha University, Korea 

Soft magnetic carbonyl iron (CI) based magnetorheological (MR) fluids with different 

loadings of nanoclay were prepared, in which the MR fluid is a complex colloidal 

suspension consisting of magnetic particles dispersed in a liquid, showing its rapid, 

reversible and tunable change between a liquid-like and solid-like state with an applied 

external magnetic field. The MR characteristics were measured via rotational tests, in 

which the flow curves exhibited a non-Newtonian behavior for all investigated samples 

under applied magnetic fields. Flow curves showed not only the dynamic yield stress 

change measured as a function of magnetic field strength using a power law fit but also 

the existence of a solid-like character. Sedimentation of the MR fluid with and without 

an additive was also examined.

QN04 

Hysteresis analysis: A study on the demanetization by using M-B 

preisach model for improved stability of numerical analysis 

Hyuk Won and Gwan Soo Park* 

School of Electrical Engineering, Pusan National University, Korea 

It is necessary to describe the hysteresis characteristic of magnetic material precisely 

for the analysis of design of system with ferromagnetic materials. Although 

Preisach model is regarded as the most accurate method to describe the hysteresis 

characteristics, it is not applied widely to the real systems because of some difficulties. 

The conventional Preisach model shows the numerical instabilities during the iterative 

computations because the density distribution obtained from the sets of M-H curves 

are strongly localized. To remove such numerical instabilities, if we use a M-B variable 

instead of M-H variable would be better the results. In this paper, we suggest method 

for a M-H variable to change a M-B variable, and also, from the computed results of 

used normal Preisach, M-H cure method and M-B curve method, we shows better than 

numerical stabilities by using two dimensional finite element method. 

QN05 

A study on the design of transmitting coils and receiving coils on active 

magnetic snesor using finite element method 

Hye Sun Ju and Gwan Soo Park* 

Pusan National University, Korea 

Proximity magnetic sensor is able to detect the object target accurately in close range 

and it has been widely used in the underwater guided weapon system because there 

is no countermeasures from the target. In order to increase the damage of target by 

shock wave due to explosion of the underwater guided weapon system, the maximum 

detection range of the proximity magnetic sensor needs to be increased. In this paper, 

we describe the techniques of the optimum transmitting and receiving coils design 

using the Finite Element Method for the output power enhancement of the transmitter 

and the sensitivity improvement of the receiver. Finally, the proposed design techniques 

of the transmitter and the receiver were verified using a experimental setup and a 

prototype. 

QN06 

What can we learn from isothermal remanent magnetization curves on 

diluted nanoparticle assemblies? 

Florent Tournus*, Arnaud Hillion, Alexandre Tamion and Veronique Dupuis 

LPMCN, CNRS & Univ. Lyon 1, France 

Isothermal remanent magnetization (IRM) and direct-current demagnetization (DcD) 

curves are mainly used to characterize interactions in a granular magnetic media and to 

determine the switching field distribution. These curves are only sensitive to irreversible 

changes, i.e. to the particle magnetization switching for samples made of clusters 

embedded in a matrix. Moreover, at remanence there is no unsuitable contribution 

(superparamagnetic, diamagnetic or paramagnetic) to the signal. This makes IRM/DcD 

curves of great interest in the investigation of the intrinsic properties of nanoparticles. The 

underlying process, i.e. macrospin switching by applying a field, is complementary to the 

thermal switching observed with ZFC/FC curves where the particle size distribution has a 

critical influence. Interestingly, IRM curves have a high sensitivity to other characteristics 

such as an anisotropy constant distribution, non-uniaxial terms of the anisotropy, and of 

course inter-particle interactions. We show how IRM/DcD curves can be modelled for an 

assembly of randomly oriented and non-interacting macrospins, thus allowing efficient 

and realistic simulations of experimental curves (taking into account the size distribution, 

temperature, etc). This modelling is then confronted to a series of measurements on diluted 

Co nanoparticle samples prepared by low-energy cluster-beam deposition. Experiment/ 

theory comparison can provide new insights on their magnetic properties. 

QN07 

QN08 

QN09 


On real-time hysteresis compensation for magentostirictive sound 

transducers 

Hae Jung Park and Young-woo Park* 

Department of Mechatronics Engineering, Chungnam National Univers, Korea 

Magnetostrictive actuators show inherent hysteresis, and it hinders wide applications. 

To solve this problem, in the literature, ‘Jiles-Atherton model’ and ‘Preisach model’ 

have been used mostly. But the methods require huge CPU time, or need complex 

mathematics. Thus, for real-time, ability of hysteresis compensation using capacitor 

is proposed by park et al [1]. In this paper, class-D amplifier containing capacitor as 

hysteresis compensator is proposed. The Class-D amplifier consists of comparator, 

current supplier and R-C circuit. Hysteresis compensator is implemented by a 

R-C circuit, because the output voltage of capacitor has similarity to a hysteresis 

compensated input, and the process of development is as follows: 1. Generation of 

Hysteresis compensated input by Preisach model; 2. Comparison between hysteresis 

compensated input and R-C circuit model by non-linear regression; 3. Application 

found capacitance to the class-D amplifier. Experimental setup is consisted of a 

capacitance displacement sensor, a digital oscilloscope and a function generator. 

Hysteresis loss observed about 19 percent before application of hysteresis compensator, 

and hysteresis loss observed less than 13 percent after application of hysteresis 

compensator at 10 Hz by using the 3 uF of capacitor. 

[1] Ki-Hyun Ji, Hae-Jung Park, and Young-Woo Park, “Semiempirical Approach to Compensate 

Hysteresis in Magnetostrictive Actuator”, IEEE <strong>International</strong> Magnetics <strong>Conference</strong> 2011, 2011 

The investigation on structural and magnetic properties of Ni-Cu-Zn- 

Mn-Mg-Li ferrites 

Chih-wen Chen*, Mean-June Tung and Shi-Yuan Tong 

Industrial Technology Research Institute, Taiwan 

In this work, addition of seven raw materials inclusive of nickel oxide, copper oxide, 

zinc oxide, manganese oxide, magnesium oxide, lithium oxide, and iron oxide to form 

a new multi-component ferrite system. The Ni-Cu-Zn-Mn-Mg-Li substituted ferrites 

were prepared by conventional solid-state-reaction process and sintered at 1100°C 

for 2 h in air atmosphere. The influences of Ni-Cu-Zn-Mn-Mg-Li substitution on 

structural and magnetic properties were investigated by scanning electron microscopy, 

RF impedance/material analyzer, B-H curve loop tracer, and vibrating sample 

magnetometer. The experimental results show that the additives with low melting point 

form precipitates at the grain boundaries.[1] The average grain size of sintered ferrites 

decreases with a decrease of Ni/Mn ratio. The sintered ferrites, Ni/Mn=0.79, showed 

largest initial permeability (μi=85), largest saturation magnetism (Bs=3930 gauss), and 

better saturation magnetization (Ms=74.91 emug-1). 

[1]Guiqing Wang, Xiufang Bian, Weimin Wang, Junyan Zhang,Mater. Lett., 57 (2003) 4083-4087. 

Magnetorheology of xanthan gum coated soft magnetic carbonyl iron 

microspheres and their polishing characteristics 

Seung Hyuk Kwon 1 , Hyoung Jin Choi 1 *, Jung Won Lee 2 , Kwang Pyo Hong 2 and 

Myeong Woo Cho 2 

1 Department of Polymer Science and Engineering, Inha University, Korea 

2 Department of Mechanical Engineering, Inha University, Korea 

Magnetorheological fluids, complex colloidal suspensions consisting of magnetic particles 

dispersed in a liquid, showing their rapid, reversible change between a liquid-like and solidlike 

state with an applied magnetic field. Among these applications, MR polishing arrests 

a lot of attention due to its smart controlling polishing characteristics for dedicated MEMS 

applications. In order to improve polishing characteristics of MR fluids, in this study, 

carbonyl iron (CI) microspheres coated with xanthan gum (XG) were fabricated via solvent 

casting method. The morphologies and densities of both pure CI and CI/XG particles were 

characterized via SEM and pycnometer, respectively. In addition, rheological characteristics 

of the MR fluids under applied magnetic field strengths were examined via a rotational 

rheometer, in which shear viscosity, storage modulus, normal force the variation in MR 

performance under applied magnetic fields. Especially, the normal force was measured 

for different gap distances to simulate the work condition of MR polishing. MR polishing 

characteristics were conducted using an MR polishing machine to investigate the surface 

roughness from the MR polishing with nano ceria slurry abrasives. A series of experiments 

were performed for fused silica glass using prepared slurry by changing the processing 

parameters such as a rotating wheel speed and polishing time. 


Poster Tuesday



QN10 

Cluster-glass-like magnetic state in rare-earth intermetallic compound 

Tb 5Pd 2 

Andrey F. Gubkin 1 *, Pavel E. Terent'ev 2 , Elena A. Sherstobitova 1 and Nikolai V. 

Baranov 3 

1 Laboratory of neutron scattering, Institute of Metal Physics, Russia 

2 Laboratory of ferromagnetic alloys, Institute of Metal Physics, Russia 

3 Laboratory of micromagnetic materials, Institute of Metal Physics, Ural Federal University, Russia 

The rare-earth intermetallic Tb 5Pd 2 compound crystallizes in a cubic crystal structure with site disorder 

and magnetic frustrations due to triangle-like arrangement of Tb atoms [1]. In this work the DC and AC 

magnetic susceptibility measurements together with powder neutron diffraction have been performed 

in order to study the Tb 5Pd 2 magnetic state. The susceptibility measurements on a polycrystalline 

Tb 5Pd 2sample have revealed a complex highly irreversible behaviour below 58 K, which can be associated 

with the existence of a spin-glass-like magnetic state. According to our neutron diffraction data the Tb 5Pd 2 

compound doesn’t exhibit a long-range magnetic down to 5 K. However below and above the freezing 

temperature TG ? 58 K, the appearance of the broad diffuse maxima of magnetic origin has been detected 

in the low angle region. The second anomaly of the susceptibility was observed at TB ? 25 K, which can 

be ascribed to the blocking process of uncompensated magnetic moments of antiferromagnetically shortrange 

correlated regions. The results obtained allow us to suggest that the Tb 5Pd 2 compound exhibits a 

complex non-ergodic magnetic state of a cluster-glass type associated with frustrations of the RKKY-type 

exchange interaction. This work was supported by the program of RAS (Projects RAS UB 11-2-НП-265). 

1. M. L. Fornasini, A. Palenzon, J. Less-Common Metals, 38, (1974) 77-82. 

QN11 

Microwave absorption properties of polymer composites with 

amorphous Fe-B and Ni-Zn-Co ferrite nanoparticles 

Kazuaki Shimba*, Shozo Yuki, Nobuki Tezuka and Satoshi Sugimoto 

Materials Science, Tohoku University, Japan 

Recently, many communication devices use GHz-range microwave. It causes serious 

issue, such as electromagnetic interference and multipath interference. To prevent these 

problem, microwave absorbers (MA) consisting of polymer composites of magnetic 

powders are paid attention. With the current trend being to miniaturize devices, thinner 

MA are now required. We reported that polymer composites with amorphous Fe-B 

particles (AFBP) and Ni-Zn ferrite nanoparticles showed high permeability of μ'r = 

9.5 at 1.0 GHz and good microwave absorption properties at 0.6-1.1 GHz and resulted 

in thinner MA than reported MA [1]. However, they cannot used as MA over 1.1 

GHz, because of their low resonant frequency (fr = 1.2 GHz). In this study, Ni-Zn-Co 

ferrite nanoparticles (NZCFN) were mixed with AFBP for increasing fr in polymer 

composites. XRD analyses show that NZCFN exhibit typical spinel structure. The fr 

of NZCFN increases from 0.7 to 3.6 GHz with increasing Co contents. It indicates 

that the magnetocrystalline anisotropy of NZCFN is increased by Co addition. The fr 

of polymer composites with AFBP and NZCFN can be increased to 2.6 GHz. They 

exhibites good microwave absorption properties at 0.8-1.4 GHz with thicknesses of 

2.4-3.9 mm and resulted in thin MA at 1-1.4 GHz. 

[1] K. Shimba, N. Tezuka, S. Sugimoto; Materials Science and Engineering B 177 (2012) 251-256 

QN12 

Magnetostrictive properties of Mn substituted sintered cobalt ferrite 

derived from nanocrystalline materials 

Khaja Mohaideen Kamal and P A Joy* 

Materials chemistry division, National Chemical Laboratory, India 

Magnetostrictive smart materials are of great importance for sensor applications. Cobalt 

ferrite is well known for its highest magnetostrictive strain at room temperature among 

the oxide based magnetostrictive materials. The substitution of manganese for iron in 

cobalt ferrite, CoFe 2O 4, increases the strain derivative even though the magnetostriction 

value is decreased for the material synthesized through the conventional ceramic route 

[1,2]. In the present study we have investigated the influence of the initial particle 

size of the powders of manganese substituted cobalt ferrite on the magnetostrictive 

coefficient of the sintered ferrite samples with compositions 0≤x≤0.3 in CoFe 2xMn 

xO 4. Nanoparticles of CoFe 2-xMn xO 4 of size less than 10 nm were synthesized by 

an autocombustion method and the resulting powders were sintered in air at 1300° C. 

Magnetic characteristics of the nanocrystalline powders and sintered products have 

been studied. Magnetostriction measurements were performed on the sintered samples 

to determine the influence of initial particle size of the starting powders. Higher 

magnetostriction at low fields is obtained along with enhanced strain derivative for the 

sintered Mn substituted cobalt ferrite derived from nanocrystalline materials compared 

to the bulk counterparts. 

1. J.A. Paulson et al. J. Appl. Phys., 97, 44502 (2005). 2. S.D. Bhame and P.A. Joy, J. Appl. Phys., 

100, 113911 (2006). 


QN13 

Magnetic Properties of Co 2Z Ferrite Densified through High BET 

Powders 

Ji Yeon Song and Young Ho Han* 

Materials Engineering, Sungkyunkwan University, Korea 

Co 2Z is a planar hexagonal ferrite that exhibits high permeability (μi) and high 

resonance frequency (fr) up to the GHz region. Z-type Ba 3Co 2Fe 24O 41 hexagonal 

ferrite was prepared by two-step calcinations [1]. Single phase Co 2Z ferrite powders 

were possible after post-calcination at 1300°C. Various sintering aids improved 

densification of ceramic bodies, but lowered magnetic permeability due to nonmagnetic 

characteristics of sintering additives. In order to increase permeability, Co 2Z 

specimen was sintered without sintering aids. The densities of sintered bodies increased 

with increasing specific surface area (BET) of calcined powders, and Co 2Z with BET 

7.80m2/g led to significantly high densification(5.23g/cm3, 97% theoretical density). 

Permeability of Co 2Z gradually increased with increasing density, whereas their 

resonance frequencies decreased with increasing permeability, where the product of μi 

x fr was estimated to be ~10.3GHz. It was thus confirmed that the calcined powders 

with high BET could enhance sintering kinetics of Co 2Z hexagonal ferrites without 

sintering additives and significantly increase magnetic permeability. 

[1] J. Jeong, K.W. Cho, D.W. Hahn, B.C. Moon, Y.H. Han, Mater. Lett. 59 (2005) 3959-62 

QN14 

Magnetic properties of Cr 3+ substituted Mg-Cd ferrites 

S A Masti 1 *, A. K Sharma 2 and P. N. Vasambekar 3 

1 Physics, Dr. Ghali College, Gadhinglaj, India 

2 Physics, Shivaji University, Kolhapur, India 

3 Electronics, Shivaji University, Kolhapur, India 

Magnetization and susceptibility of polycrystalline ferrites with general formula Cd x 

Mg 1-x Fe 2-y Cr y O 4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0; y = 0, 0.05 and 0.10) were studied. 

Study of saturation magnetization reveals that the Neels two sublattice model exists 

up to x = 0.4, for y = 0, 0.05 and 0.1 and a three sublattice model (YK-model) is 

predominant for x > 0.4, y = 0, 0.05 and 0.10. The saturation magnetization and 

magnetic moment were found to decrease with the increase of Cr 3+ contents, which is 

attributed to the dilution of B-B site interaction. Temperature dependence normalized 

AC susceptibility study reveals that MgFe 2O 4 exibits single domain(SD) structure. On 

substitution of Cd 2+ , single to multi domain transition takes place. Curie temperature 

decreases with Cd 2+ ,was attributed to decrease in A-B intraction. On substitution of 

Cr 3+ , peak obtained in MgFe 2O 4 was supressed which is attributed to decrease in grain 

size and further decrease 

QN15 

Docking Speaker Based on Magnetostrictive Sound Transducer 

Han Sam Kang, Jin Hong Min and Young Woo Park* 

Department of Mechatronics Engineering, Chungnam National University, Korea 

All docking speakers available in the market are equipped with iDevice cradle and 

with cone-type sound unit. This paper presents a novel docking speaker without them. 

It is based on the magnetostrictive sound transducer (MST), which transforms any flat 

surface into speaker. The docking speaker consists of one MST, two circuit boards, and 

aluminum housing. One circuit board contains a Bluetooth module, a power amplifier 

module, Aux, and a recharge adapter. The other board is called a control board, which 

ATmega128 is used to control a digital clock, a LCD module, four control switches, 

and a power amplifier module. The reluctance concept is utilized to the magnetic circuit 

for the MST. Allowable current and number of coil turns are determined through this 

procedure. The result is compared with the simulation result. Then, circuit board and 

housing are designed. The assembled docking speaker is subjected to the experiments. 

For the experiments, the MST is placed and bolted between the wood and glass panels. 

An accelerometer sensor, ADXL001, is firstly located beneath the center of the MST. 

Then, the location is placed away by 50 mm from the center of the MST. It is proved 

that the developed docking speaker works well.

QN16 

Characteristics of composite materials Ba 0.5Sr 0.5Fe 11.7Mn 0.15Ti 0.15O 19/ 

La 0.7Ba 0.3MnO 3 as a microwave absorber 

V. Vekky R. Repi* and Azwar Manaf 

Graduate Program of Materials Science Study, Universitas Indonesia, Indonesia 

QN17 

The effect of shape anisotropy to acoustical performance of 

magnetostrictive sound transducer 

Hae Jung Park, Young Woo Park* and Ok Kyun Oh 

Department of Mechatronics Engineering, Chungnam National Univers, Korea 

This paper presents the experimental approach to investigate the effect of the 

shape anisotropy of magnetostrictive material (MM) to acoustical performance of 

magnetostrictive sound transducer. The assumption is that the volume of MM is kept 

constant. In the experiments, four MM samples are used with a volume of 295 mm^3 

and input currents are swept from 20 Hz to 20 kHz. The diameters of MM samples 

are 4, 5, 6 and 10 mm and the lengths are 23.5, 15, 10.5 and 3.5 mm, respectively. The 

displacements are measured from 2.1 to 0.8 um at 20 Hz. Forces are measured from 

81 to 120 N at 20 Hz. Among the samples, the MM sample of 23.5mm length shows 

the largest displacement and force. SPL is obtained from forces of MM and a area 

of vibration panel. The largest SPL is observed at 20 Hz and the SPL is measured to 

115dB. Also, the SPL of the samples show the level from 103 dB at 1 kHz to 81 dB at 

20 kHz. The displacement and force are measured from 0.36 um and 29N at 1 kHz to 

15.3 nm and 2.5 N at 20 kHz. 

QN18 

WITHDRAWN 

Size effects on magnetic properties of nanocrystalline Sr 2CuCo 2Fe 24O 41 

prepared by Co-precipitation method 

K Praveena and K Sadhana 

Materials Research Centre, Indian Institute of Science, India 

The nanocrystalline z-type hexaferrite powders were synthesized by Co-precipitation 

method using aqueous solutions of strontium, copper, cobalt iron and nitrates. The 

as synthesized powders were characterized using XRD, TEM and TG/DTA. The 

average particle size of the powders was found to be 48nm.The effect of calcinations 

temperature on crystallinity, morphology and magnetic properties have been 

investigated. The sintered samples were characterized using XRD, FE-SEM and EDS. 

The hexagonal ferrite formation was observed around 900°C which is confirmed with 

the TG/DTA curves. The plate shape grains were observed in FE-SEM at 950°C. The 

grain sizes of sintered hexaferrites are in the range of 220nm to 850nm. The value of 

Ms= 70 emu/g and Hc=540 Oe was obtained at 900°C/5h. 

QN19 

QN21 


Structural and magnetic properties of Mn 2Rh 1-xCo xSn Heusler alloys 

Olga Meshcheriakova 1 , Jurgen Winterlik 1 , Gerhard H. Fecher 2 , Benjamin Balke 1 and Claudia Felser 3 

1 Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Germany 

2 Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Max 

Planck Institute for Chemical Physics of Solids, Dresden, Germany 

3 Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Max 

Planck Institute for Chemical Physics of Solids, Dresden,, Germany 

Mn 2-based Heusler compounds are promising candidates for spintronic applications as they are 

known to crystallize with cubic and tetragonal structures or exhibit cubic-tetragonal phase transitions. 

Sn-containing compounds have only a small lattice mismatch with MgO thus providing higher 

symmetry correlation between magnetic film and tunneling barrier. Quaternary Mn 2Rh 1-xCo xSn 

and Mn 2+xRh 1-xSn Heusler alloys have been synthesized with a step of x = 0,1 and their magnetic 

properties were experimentally investigated. In the present work the structural and magnetic properties 

are discussed depending on the Rh and Co content. The frst series undergoes a cubic-tetragonal 

transition at x = 0,5, while the latter one experiences a hexagonal-tetragonal change of structure. The 

presence of Co increases the Curie temperature keeping the magnetic moment unchanged. This work 

is supported by the Graduate School of Excellence Materials Science in Mainz (MAINZ). 

[1] Simple Rules for the Understanding of Heusler Compounds, Tanja Graf, Stuart S. P. Parkin, and Claudia Felser, 

Progress in Solid State Chemistry 39 (2011) 1-50, invited review. doi:10.1016/j.progsolidstchem.2011.02.001. [2] 

Electronic, magnetic, and structural properties of the ferrimagnet Mn2CoSn, Jurgen Winterlik, Gerhard H. Fecher, 

Benjamin Balke, Tanja Graf, Vajiheh Alijani, Vadim Ksenofontov, Catherine A. Jenkins, Olga Meshcheriakova, and 

Claudia Felser 83 (2011) 174448. [3] Quaternary half-metallic Heusler ferromagnets for spintronics applications, 

V Alijani, J. Winterlik, G. H. Fecher, S. S. Naghavi, C. Felser, Phys. Rev. B 83 (2011) 184428 

QN20 

Magnetic properties of Mn 2Sb 1-xGe x (0.05 ≤ x ≤ 0.2) in high magnetic 

fields 

Daisuke Shimada 1 *, Hiroki Orihashi 1 , Daisuke Mitsunaga 1 , Kohki Takahashi 2 , 

Masahiko Hiroi 1 , Masakazu Ito 1 , Kazuyuki Matsubayashi 3 , Yoshiya Uwatoko 3 and 

Keiichi Koyama 1 

1 Kagoshima University, Japan 

2 Tohoku University, Japan 

3 Tokyo University, Japan 

The Mn 2Sb compound with a Cu 2Sb-type tetragonal structure is ferromagnetic (FRI) below TC ~ 

550 K. The substitution of various elements (V, Cr, Co, Cu and Zn) for Mn as well as (As, Ge and 

Sn) for Sb results in a first-order magnetic (FOM) transition from the ferromagnetic (FRI) to an 

antiferromagnetic (AFM) states with decreasing temperature [1]. Mn 2-xCoSb, it has been reported 

that the FOM transition occurs accompanied with large change in unit cell volume, resistivity and 

magnetization etc. However, detailed results on Mn2Sb 1-xGe x have not been reported yet. In this 

study, magnetization and electrical resistivity measurements were carried out for polycrystalline 

Mn 2Sb 1-xGe x (0.05 ≤ x ≤ 0.2) in magnetic fields up to 16 T in 4.2-600 K temperature range, in order 

to investigate the magnetic and electrical properties affected by magnetic fields. Mn 2Sb 0.92Ge 0.08 

showed the Curie temperature Tc of 532 K and the FOM transition at Tt = 230 K in a zero magnetic 

field. With increasing x, Tc decreased and Tt increased. For Mn 2Sb 0.92Ge 0.08, we observed a 

matamagnetic transition from the AFM to FRI with a hysteresis of 0.5 T at 200 K. 

[1] O. Beckman and L. Lundgren: Handbook of Magnetic Materials vol 6, ed K H J Buschow 

(Amsterdam: Elsevier) chapter 3, (1991) p 181-287 

Microwave magnetic properties of FeNi films prepared by 

electrodeposition 

Dong Zhou1, Wei Li 1 , Minggang Zhu 1 *, Yanfeng Li 1 , Wei Sun1 and Fashen Li 2 

1 Central Iron & Steel Research Institute, China 

2 Lanzhou University, China 

With the development of computers and communication devices using the 

electromagnetic wave of GHz range, the serious electromagnetic interference (EMI) 

have been emerged. The electromagneic wave absorbers have been widely investigated 

to eliminate the EMI problems. Electrodeposition is one of the simplest, most 

flexible, and cheapest processes available for the fabrication of single component and 

multilayered thin films. In this study, FeNi alloys thin films have been successfully 

electrodeposited on Ag films. The morphology, structure, composition, and magnetic 

property of the FeCo films were characterized by scanning electron microscopy, 

x-ray diffraction, energy dispersive spectrometer, vibrating sample magnetometer and 

network analyzer. With the increase of depostion time, the coercivity of deposited 

FeNi films reduce until getting a minimum value and the the real part of permeability 

increase. At the same time, the increase of the thickness leads to the decrease of 

resonance frequency. We also study the effect of the compostion on the coercivity and 

microwave magnetic properties. By changing the compositon of FeNi alloy films, the 

effective permeability and the resonance frequency can be adjusted. 


Poster Tuesday



QN22 

Preparation and characterization of ferromagnetic fluid and magnetorheological 

fluid 

Tae Min Hong 1 , Jong Hee Kim 2 , Cheolgi Kim 3 and Seung Goo Lee 1 * 

1 

Advanced Organic Materials & Textile System Engineering, Chungnam National 


2 

Research Center for Advanced Magnetic Material, Chungnam National University, 

Korea 

3 

Materials Science & Engineering, Chungnam National University, Korea 

Ferromagnetic fluid and magneto-rheological fluid are liquids that nanometer-sized 

particles of iron dispersed in the medium. PEG(polyethylene glycol) and silicon 

oil were used as the fluidic media. Fluids are flexible dispersion state under a nonmagnetic 

field. But, under a magnetic field, particles are oriented in the direction of the 

magnetic field and the fluid shows the solid-like behavior. In this study, we studied to 

know how the magnetic field impacts the yield stress of ferromagnetic and magnetorheological 

fluids. Yield stress of the fluid is evaluated by the viscosity measurement. 

Viscosity behaviors of ferromagnetic and magneto-rheological fluids are measured 

with a magneto-rheological viscometer (MCR 301, Anton paar, Austria) with applying 

magnetic field from the plate. Two types of experiment were conducted. One is a static 

test in which the viscosity of fluids is measured with increasing shear rate while the 

applied magnetic field is fixed. The other one is a dynamic test in which the viscosity 

of fluids is measured with increasing magnetic field while shear rate is fixed. As the 

results, viscosity of ferromagnetic fluid and magneto-rheological fluid increased largely 

by applying magnetic field in all conditions. 

QN23 

Microwave magnetic and absorbing properties of the planaranisotropy 

Ce 2Fe 17N 3-δ powder composite 

Jianqiang Wei, Wenliang Zuo, Tao Wang and Fashen Li* 

Key Laboratory of Magnetism and Magnetic Materials of Ministry of Education, 

Lanzhou University, China 

Ce 2Fe 17N 3-δ powders were prepared by arc-melting, milling and nitrogenation. The microstructure 

and static magnetic properties of the powders were analyzed by x-ray diffraction (XRD) and 

vibrating sample magnetometer (VSM), respectively. The c-plane alignment of Ce 2Fe 17N 3-δ was 

evaluated with the XRD data of an aligned composite sample. The effective complex permeability 

of Ce 2Fe 17N 3-δ powders/epoxy resin composite was measured in the frequency range of 0.1-15 GHz. 

The intrinsic static permeability of Ce 2Fe 17N 3-δ powder was calculated by Bruggerman (BG) effective 

medium theory. The natural resonance frequency of Ce 2Fe 17N 3-δ was obtained using Landua-Lifshitz- 

Gilbert (LLG) equation. The Snoek's product of the effective static susceptibility and the resonance 

frequency is much larger than the Snoek's limit of the composite. The reflection loss of the composite 

sample was determined by simulation and by measuring the S11 parameters after rear face of 

sample was terminated by metal. The minimum reflection loss was found moving towards the lower 

frequency region with increasing the sample thickness. Quantitatively analysis reveals that the peak 

frequencies (fp) of the dips (minimum reflection loss), the μ(fp), the ε(fp) and the sample thickness 

obey the quarter-wavelength (λ/4) formula. Accordingly, the quarter-wavelength formula have been 

successfully applied to explain and predict the microwave absorbing properties. 

This work is supported by the National Basic Research Program of China (Grant No. 

2012CB933101) and the National Natural Science Foundation of China (Grant No. 11144008). 

QN24 

Co 2Y-NiCuZn ferrite composites for high frequency applications 

Ruei-lin Lin and Hsing-i Hsiang* 

Resources Engineering, National Cheng Kung University, Taiwan 

The most commonly used materials in inductors for high-frequency applications are 

NiCuZn ferrites, or non-magnetic materials such as low-temperature cofired ceramics. 

The non-magnetic materials are used for high-frequency applications because NiCuZn 

ferrites (ferroxcube) typically exhibit severe property changes above 200MHz due to 

the Snoek limit. The maximum quality factor frequency in chip inductors made of nonmagnetic 

material is over 500 MHz. However, the quality factors at frequencies around 

200-300MHz are much lower than those at higher frequencies. Because chip inductors 

are prepared by winding a wire around a non-magnetic material core it is necessary 

to have a larger number of coil winding turns to obtain the desired inductance; thus 

limiting miniaturization. Therefore, it is desirable to develop a magnetic material that 

has a higher initial permeability and quality factor than non-magnetic materials at 200- 

300 MHz, for use in making high frequency inductors. In this study, a Co 2Y-NiCuZn 

ferrite composite with high permeability was prepared by coating NiCuZn ferrites onto 

the surface of Co 2Y ferrites using heterogeneous nucleation process. The effects of 

NiCuZn ferrites addition on the densification behavior, micro-structure and magnetic 

property of Co 2Y-NiCuZn ferrite composites were investigated. 


QN25 

A novel low-temperature-fired multifunctional varistor-magnetic 

NiCuZn ferrites 

Wei-hung Hsu, Hsing-i Hsiang* and Li-then Mei 

Resources Engineering, National Cheng Kung University, Taiwan 

A novel low temperature-fired(950°C) multifunctional varistor-magnetic ferrite 

materials can be obtained by adding Bi 2O 3 into Zn 0.5Ni 0.3Cu 0.19Nb 0.01Fe 2.02O 4 ferrites. 

The relationship between the microstructure and varistor properties were investigated 

using scanning electron microscopy (SEM), X-ray Diffraction (XRD), and impedance 

analysis. For Zn 0.5Ni 0.3Cu 0.19Nb 0.01Fe 2.02O 4 ferrites with 2.5wt% Bi 2O 3 content 

sintered at 950°C for 2h, the nonlinearity exponent (α) can reach 5.1 and the initial 

permeability(μ) is about 200 to 250. Moreover, the αvalue can be promoted to 67.8 for 

the Zn 0.5Ni 0.3Cu 0.19Nb 0.01Fe 2.02O 4 ferrites added with 9Bi 2O 3-CuO sintered at 950°C for 

2h. 

QN26 

Synthesis and magnetic properties of transition metal ferrite 

nanoparticles 

Tejabhiram Yadavalli 1 , Shivaraman Ramaswamy 1 , Gopalakrishnan Chandrasekaran 1 

and Ramasamy R 2 

1 Nanotechnology Research Centre, SRM University, India 

2 School of Pharmacy, SRM University, India 

The use of ferromagnetic metal ferrite particles for magnetic hyperthermia application 

has been extensively studied by many scientists. The use of ferromagnetic particles with 

low curie temperatures result in the formation of self regulated magnetic hyperthermia. 

In this context, multiple experiments on synthesizing ferrite nanoparticles with varying 

cobalt and nickel oxide concentrations have been done. The products were analyzed 

using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction 

and vibrating sample magnetometer. The microscope images indicated the formation 

of nanoparticles while the spectroscopy and diffraction patterns indicated the formation 

of nickel and cobalt ferrite nanoparticles along with additional nickel oxide and cobalt 

oxide. Magnetometer analysis conducted on the samples indicated a reduced magnetic 

saturation and hysteresis. Hysteresis loss energy was determined by calculating the area 

under the hysteresis loop, frequency of the magnetic field and the curie temperature of 

the material. The results indicated a two-fold decrease in the hysteresis energy giving a 

hint for their use in controlled magnetic hyperthermia treatment. 

QO01 

High room temperature power factor (Z) in K xRhO 2 

Nirpendra Singh, Yasir Saeed and Udo Schwingenschlog l * 

King Abdullah University Science and Technology Thuwal, Saudi Arabia 

We discuss the thermoelectric and optical properties of layered K xRhO 2 by means of 

the electronic structure determined by first principles calculations as well as Boltzmann 

transport theory. The main contribution to the optical spectra are due to intra and interband 

transitions between the Rh 4d and O 2p states. Our results of transport perproties 

of K xRhO 2 at room temperature show highest value among hole-type materials. 

Specially at 100 K, the Z value of K xRhO 2 is 3x10 -3 K -1 . Our results show that the 

electronic and optical properties of K xRhO 2 are similar to Na xCoO 2 with an enhanced 

transport properties.

QO02 

Optimized Halbach array based magnet systems for Lorentz force 

velocimetry purposes 

Michael Werner 1 * and Bernd Halbedel 2 

1 University of Technology Ilmenau, Germany 

2 Department of Inorganic-Nonmetallic Materials, University of Technology Ilmenau, 

Germany 

Lorentz Force Velocimetry (LFV) is in research since 2003. The Lorentz force acting 

on a source magnet system is providing a velocity dependent signal. The efficiency of 

the magnet system (ratio of generated Lorentz forces to the mass of the system) is an 

essential parameter for sufficient resolutions of the whole LFV sensor device. The full 

article will propose a very efficient combination of permanent magnet arrays, where 

the particular permanent magnets have different magnetization directions. Here an 

iron yoke is not necessary, respectively ineffective, and so the arrays can be assembled 

with a very light carbon fiber composite fixture in order to reduce the overall mass 

further. The underlying principle of this array combination will be presented and the 

geometric optimization with commercial software, as well as the assembling method, 

will be explained. On an experimental test channel for LFV on electrolyte flows the 

magnet system is tested and compared to another simple standard magnet system with 

single permanent magnet blocks instead of the arrays. From previous finite element 

simulations an increase of a factor of three in efficiency is estimated and will be proven 

in the experiment. Further improvement using cladding technique will be introduced 

too. 

QO03 

Growth and characterization of SmFe 6Ge 6 single crystals 

Rodrigo S. Monteiro, Lucas K. Piquini, E. Thizay Magnavita, Raquel A. Ribeiro and 

Marcos A. Avila* 

Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Brazil 

Hexagonal single crystal plates of SmFe 6Ge 6 have been grown by the flux method 

using a 4th flux element (Sn), extending the range of members in the RFe 6Ge 6 family 

of magnetic compounds, whose physical properties have so far been described 

only for rare earths R = Gd-Lu [1]. This family exhibits antiferromagnetic (AF II) 

ordering at 450 K of the layered Fe honeycomb sublattice, and independent ordering 

(or no ordering) of the R sublattice moments below 30 K. Here we present a basic 

characterization of the structural, magnetic and transport properties of the SmFe 6Ge 6 

crystals and compare the general anisotropic behavior with other members of the 

family. We thank the support of Brazilian agencies FAPESP and CNPq. 

[1] G. Venturini, R. Welter and B. Malaman, J. Alloys Comp. 185 (1992) 99-107. 

QO04 

Anomalous magnetic and related properties of Nd 5Ge 3 

Bibekananda Maji 1 *, K G Suresh 1 and A K Nigam 2 

1 Physics, Indian Institute of Technology Bombay, Mumbai- 400076, India 

2 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai- 400005, 

India 

We have observed that the stoichiometric intermetallic compound Nd 5Ge 3 shows many 

anomalies in the magnetization, resistivity and heat capacity data. This compound 

undergoes an antiferromagnetic (AFM) transition at 46 K and another one at 30 K on 

cooling. It is found that the strengths of these two antiferromagnetic states are different. 

Ultra-sharp jumps are seen in the low temperature isotherms of magnetization, heat 

capacity and electrical resistivity. Another important anomaly is the field-induced 

irreversibility in all these three properties, which suggests that the spin, electronic and 

lattices states are strongly coupled in this compound. The memory effect seen here is 

quite remarkable and is consistently seen in various measurements. Another striking 

observation is the spontaneous evolution of the ferromagnetic (FM) phase as a function 

of time, at a fixed temperature and at the critical field. Sweep rate and cooling field 

dependencies point towards the role of martensitic strains in the anomalous behavior. 

The compound appears to show the coexistence of FM and AFM components at low 

temperatures. The features seen in this compound indicate the presence of disorder in 

influencing the magnetic and related properties considerably. The correlation of various 

properties as seen from the martensitic scenario will be presented. 

QO05 

QO06 

QO07 


Magnonic meta- and meta-meta-materials 

Rostislav V. Mikhaylovskiy 1 *, Michal Mruczkiewicz 2 , Maciej Krawczyk 2 and 

Volodymyr V. Kruglyak 1 

1 School of Physics, University of Exeter, United Kingdom 

2 Faculty of Physics, Adam Mickiewicz University, Poznan, Poland 

We report on magnonic metamaterials represented by a system of magnetic layers 

separated by those of a dielectric non-magnetic material. In such a metamaterial, the 

constituent elements are made from a magnetic material that provides an easy way 

to control its electromagnetic response by tuning the bias magnetic field. Firstly, we 

report a theory of the effective permeability of planar multilayered metamaterials 

containing thin ferromagnetic layers with magnetization pinned on either one or both 

surfaces. The pinning of the magnonic modes at film surfaces facilitates their coupling 

to the uniform magnetic field of the incident electromagnetic wave. We demonstrate 

that such structures, for magnetic parameters characteristic for conventional transition 

metal alloys, exhibit a negative refractive index at sub-THz frequencies. Furthermore, 

we show how the constituent magnetic layers of such systems could themselves be 

nanostructured into planar magnonic crystals, with the whole structure therefore 

representing a meta-metamaterial. Due to the additional nanostructuring, the negative 

permeability at sub-THz frequencies can be achieved as a result of a small lattice 

constant and lateral quantization of spin waves. Finally, we discuss the prospects for 

fabrication of such metamaterials and their experimental studies. 

Understanding the nature of magnetic phase transition in relevance to 

magnetic refrigeration 

S M Yusuf* 

SOLID STATE PHYSICS DIVISION, BHABHA ATOMIC RESEARCH CENTRE, 

MUMBAI 400085, India 

It is important to understand the nature of magnetic phase transition for a material suitable for magnetic 

refrigeration. With this aim, we have studied a wide class of intermetallic compounds with diversity in their nature 

of magnetic ordering and phase transition, such as ferromagnetic ordering, ferrimagnetic ordering, coexistence 

of ferromagnetic and antiferromagnetic ordering, metamagnetic transition, and magnetostructural transition. The 

dependences of the nature of magnetic phase transition on temperature, magnetic field and chemical substitutions 

have been investigated. The role of the nature of exchange interaction and universality class in determining 

magnetocatoric effect (MCE) has been brought out by investigating the intermetallic compounds TbCo 2-xFe x and 

Mn 4FeGe 3-xSi x. A phase coexistence of ferromagnetic and antiferromagnetic phases has been observed in Cu 1xNi 

xMnSb semi-Heusler alloys around x = 0.15 where a large MCE is found as a low applied magnetic field 

causes an AFM to FM phase transformation. A broad operating temperature range due to coexistence of AFM 

and FM phases, and quenched disorder has also been obtained. The role of other interesting phenomena, such as 

metamagnetic transitions and domain wall pinning in obtaining a large MCE and an inverse MCE, respectively, 

has been brought out through the investigation of the intermetallic compounds NdMn 2-xCo xSi 2. 

[1] M. Halder, S. M. Yusuf, M. D. Mukadam, and K. Shashikala, Phys. Rev. B 81, 174402 (2010). [2] M. 

Halder, S. M. Yusuf, A. Kumar, A. K. Nigam and L. Keller, Phys. Rev. B 84, 094435 (2011). [3] M. Halder, S. 

M. Yusuf and A. K. Nigam, J. Appl. Phys. 110, 113915 (2011). [4] M.D. Mukadam, and S.M. Yusuf, Physica B: 

Cond. Matter 405, 686 (2010). [5] M. D. Mukadam and S. M. Yusuf, J. Appl. Phys. 105, 063910 (2009). 

Specific heat study on successive magnetic transitions in α-Dy 2S 3 single 

crystal under magnetic fields 

Shuji Ebisu*, Yuji Ushiki and Shin Takahashi 

Division of Applied Sciences, Muroran Institute of Technology, Japan 

Specific heat measurements in magnetic fields have been performed on α-Dy 2S 3 single 

crystal which shows successive magnetic transitions at TN1 = 11.5 K and TN2 = 6.4 

K¹. The specific heat in no magnetic field exhibits sharp peaks at both temperatures 

of TN1 and TN2. The change of magnetic entropy at each transition is estimated as 

N0kBln 2 per mole of Dy 2S 3, which suggests Dy moments on only one site between two 

crystallographically inequivalent Dy sites order at each transition temperature. When 

the magnetic field is applied along the b-axis of the orthorhombic system, two peaks of 

the specific heat shift toward lower temperatures. On the other hand, the magnetic field 

perpendicular to the b-axis shifts the peaks toward higher temperatures. The transition 

temperature TN1 shifts to 9.6 K (H//b) and 12.5 K (H┴b) with keeping sharpness of 

the peak under the magnetic field of μ0H=2 T. The peak of TN2 broadens gradually 

with increasing the magnetic field for each direction, and the peak is consequently 

obscure under the field of 2 T. 

¹ S. Ebisu, M. Narumi, M. Gorai and S. Nagata, J. Magn. Magn. Mater. 310, 1741 (2007). 


Poster Tuesday



QO08 

Magneto-inductive wave in periodic chains of ferrite cores and chip 

capacitors 

Yongmin Kim and Kwang-ho Shin* 

Dept. of Information and Communication Engineering, Kyungsung University, Korea 

In this paper, we present a new magneto-inductive wave generated in a chain of 

resonators fabricated with ferrite cores and chip capacitors. RF signal propagates to 

neighbor resonator one by one as a consequence of the magnetical coupling between 

two resonators in our device. The magnetical coupling is due to the mutual inductances 

along chains of resonators. So, the signal amplitude (? coupling intensity) is inversely 

proportional to the distance between two elements. In order to design the device, some 

electromagnetic simulations and experiments have been carried out systemically. 

The transmission characteristics of a magneto-inductive wave could be controlled by 

applied external magnetic field. For, the device composed of 5 resonance elements, 

the center frequencies were estimated to be 41.1 MHz and 34.8 MHz with the external 

magnetic flux density of 750.72 G and 2680 G, respectability. The reported result 

opens a promising way to a high variety of applications in one- and two-dimensional 

functional devices, such as transducers, delay lines, power dividers and couplers. 

QO09 

Large refrigerant capacity in Ni2.9Co0.1MnIn type-Heusler alloy 

Catalina Salazar Mejia 1 , Angelo M Gomes 1 , Ana Lima Sharma 2 and Fivos R 

Drymiotis 3 

1 

Instituto de Fisica, Universidade Federal do Rio de Janeiro, Brazil 

2 

Materials Physics Department, Sandia National Laboratory, Livermore, CA, United 

States, USA 

3 

Department of Physics and Astronomy, Clemson University, Clemson, SC, United 

States., USA 

Magnetic refrigeration (MR) is a cooling method that is based on the magnetocaloric effect (MCE). Our 

research effort focuses on identifying magnetic structures that may have improved efficiency with suitable 

characteristics for MR i.e. good magnetocaloric properties with small or zero thermal and magnetic 

hysteresis. Some Heusler alloys may meet these criteria. The Ni 2MnIn full-Heusler alloy exhibits a secondorder 

paramagnetic to ferromagnetic transition at 300 K, but its MCE is small [1,2]. However, we observe 

a large improvement in the refrigerant capacity (RC) value when the Ni 2MnIn is Co and Ni-doped. In this 

paper, we present the study of the magnetic, structural and magnetocaloric properties of the Ni 2.9Co 0.1MnIn 

Heusler-type alloy. The samples crystallizes in a cubic structure. Magnetization measurements show a 

ferromagnetic transition at 207 K. The transition is almost 40 K wide, and thermal hysteresis is negligible. 

The magnetic entropy change, ΔSM, for ΔH=5T, was calculated from heat capacity data and the maximum 

value found is -2.75 J/kg K, with broad temperature range which leads to RC=261.3 J/kg. The large RC 

value found and the absence of thermal hysteresis makes this material a good candidate for magnetic 

refrigeration applications. C.S.M. and A.M.G. would like to thank CNPq and FAPERJ. 

[1] T. Krenke, et al., Phys. Rev. B 73, 174413 (2006). [2] C. Salazar Mejia, et al., unpublished. 

QO10 

Reduction of weak localization strength on controlling oxygen defects 

by ex-situ annealing 

Seong-min Choo 1 , Kyujoon Lee 1 , Sungmin Park 1 , Gwang-seo Park 1 , Jungwon Jang 2 , 

Jinhee Kim 2 and Myung-hwa Jung 1 * 

1 Department of Physics, Sogang university, Korea 

2 Korea Research Institute Standard Science, Korea 

We have studied Pb-based gapless semiconductors, which are very sensitive to external 

parameters such as temperature, pressure, magnetic field, electric field, etc [1]. Based 

on the theoretical paper, this material has a strong spin-orbit interaction. So, we have 

fabricated pure PbPdO 2, Co- and Mn-doped PbPdO 2 thin films. Because a Pb is an 

easily vaporized element when we grow the films, the films have a lot of oxygen 

vacancies. It may induce other problems. For example, Pd is unstable state as Pd+1 

and the oxygen vacancies act as additional hole carriers. To study intrinsic properties 

of doped PbPdO 2 thin films, we tried to various methods to enhance the films quality. 

Because Pb is hard to handle in growth process, we have annealed thin films with 

different annealing time, temperature, and environments after deposition. The carrier 

densities for all the samples are deceased with annealing time while the electric 

resistivities are changed in different way. More importantly, weak localization strength 

is most likely to be reduced by ex-situ annealing. Furthermore, magnetoresistance ratio 

is also reduced by increasing ex-situ annealing time. 


QO11 

Reconstruction of cubic rs-ZnO on MgO (200) substrate through 100 

plane of w-Zn for transparent electronic application 

Chungman Kim 1 , Santosh M Bobade 1 , Seong-min Choo 1 , Suhyun Kim 1 , Kyung Ho 

Shin 2 and Myung-haw Jung 1 * 

1 Sogang University, Korea 

2 Korea Institute of Science and Technology, Seoul, Korea 

ZnO crystallizes in various crystallographic forms. However, wurtzite (w) ZnO is 

generally observed structure while the rock salt (rs) structure of ZnO appear at high 

pressure. We present rs-ZnO structure grown on MgO (200) substrate at certain 

growth environments, not high pressure. The lattice constant of MgO. The possible 

configurational path for transformation is proposed, so that the compression of w-ZnO 

along c-axis and movement of Zn or O sublattice along (110) direction and (110)plane. 

These results are confirmed by X-ray diffraction and X-ray photoemission spectrum 

experiments. It has also been observed that rs-ZnO on MgO substrate is stable for 

certain minimum thickness (in this case, it is 150nm) and possible be stabilize at lower 

temperature for few nm thickness 

QO12 

Magnetic cooling machine prototype based on cold rolled Gd foil 

Sergey V. Taskaev*, Vasiliy D. Buchelnikov, Victor V. Nikolenko, Ivan A. Chernets 

and Andrey N. Denisovsky 

Physics department, Chelyabinsk State University, Russia 

With the discovery of the “giant magnetocaloric effect“ (Pecharsky and Gschneidner, 1997) 

the development of magnetic refrigeration gained increased momentum [1]. One of the 

ways of engineering MCE materials is tightly connected with preparing very thin (a few 

microns) ribbons of high value MCE alloys with good mechanical properties. At present rapid 

solidification is the main technique for producing this kind of materials [2]. In our work we 

present magnetic cooling device which is used Gd cold rolled samples of different thickness as 

a working body. Magnetocaloric, mechanical and other properties of this material are discussed 

Morphology of the surface was investigated by AFM methods. Magnetocaloric effect was 

measured by direct method on AMT&C setup. Mechanical properties was investigated on 

Netzsch DMA 242C. Magnetic properties was measured on SQUID magnetometer. X-ray 

analysis was performed on Brucker D8 Advance difractometer. Several axial magnetic systems 

are proposed as the source of high gradient magnetic field. Depending on the air gap of 

magnetic system the residual magnetic induction is in 600 mT..1900 mT range. It is shown, that 

cold rolling technique is the alternative way for producing thin ribbons of MCE materials with 

good mechanical properties for magnetocaloric application. 

1.Gschneidner K.A. Jr. et al. Thirty years of near room temperature magnetic cooling: Where we are 

today and future prospects, Int. J. Refrig, 31, 945 (2008). 2.P. M. Shan et al. Magnetic behavior of 

melt-spun gadolinium, Phys. Rev. B. 77, 184415 (2008). 

QO13 

Research on the orbital state of IrO2 with resonant x-ray scattering 

method 

Yasuyuki Hirata 1 , Kenya Ohgushi 1 , Junich Yamaura 1 , Hiroyuki Ohsumi 2 , Soshi 

Takeshita 2 and Takahisa Arima 3 

1 


2 

RIKEN SPring-8, Japan 

3 

Department of Advanced Materials Science, University of Tokyo, Japan 

In the 5d electron systems of iridium oxides, the crystal fields, the Coulomb repulsion, and 

the spin-orbit interaction compete with each other, which results in various exotic physical 

properties. For example, magnetic iridium oxides Sr 2IrO 4 and CaIrO 3 are known to be 

spin-orbit-induced Mott insulators: the reported resonant x-ray scattering experiments 

showed that 5d t2g orbitals of Ir are reconstructed by the spin-orbit interaction and realize 

the complex Jeff=1/2 orbital states, which form a narrow band and enhance the electron 

correlation.[1] On the other hand, the orbital states of metallic iridium oxides like IrO 2, 

which is attracting attention for a gigantic spin-Hall effect, are yet to be investigated. We 

performed a resonant X-ray scattering measurement for metallic iridium oxide IrO 2 which 

has a rutile-type structure, and observed the 0 0 3 reflection coming from the anisotropic 

tensor of susceptibility (ATS). In the energy spectrum the peak corresponding to the 

excitation to 5d t2g orbitals appeared around the L3 absorption edge, but did not appear 

around the L2 absorption edge. These results indicate that the complex Jeff=1/2 states of 

5d t2g orbitals are realized even in metallic iridium oxides IrO 2. 

[1] B. J. Kim et al., Science 323, 1329 (2009).

QO14 

Investigation of magnetic-field tunable properties of 

magnetorheological elastomers 

Nikolai Perov 1 *, Anna Semisalova 1 , Elena Yu Kramarenko 1 , Alexey R Khokhlov 1 and 

Gennady V Stepanov 2 

1 Lomonosov Moscow State University, Russia 

2 State Research Institute for Chemistry and Technology of Organoelement 

Compounds, Moscow, Russia 

In this work we present the results of investigation of magnetic field influence on the 

value of dielectric permittivity and magnetic susceptibility in magnetorheological 

elastomers (MRE) based on the powders with various magnetic properties - Fe, FeNdB 

and Fe 3O 4. Both magnetic susceptibility and dielectric permittivity have been found to 

be considerably changed under magnetic field, the changing of permittivity value up to 

150% has been observed. The field dependence of the dynamic dielectric permittivity 

was significantly non-linear. The anisotropy of field influence on the permittivity and 

susceptibility was observed as well. The saturation magnetization and coercivity of the 

magnetic fillers have been shown to be the most important factors affecting the field 

dependence of permittivity. In addition, the size and concentration of particles as well as 

conductivity of magnetic material have significant influence on the type of field effect. 

The influence of named parameters on the permittivity and susceptibility changing is 

discussing; we consider the mechanisms determining the features of magnetic field 

influence on studied physical properties in detail. It is shown that MRE based on various 

magnetic particles can be considered as promising materials with magnetic-field tunable 

properties. Supported by Russian Foundation for Basic Research. 

QO15 

Disagreement between modification methods for magnetism-absorbing 

agent 

Wu Chao, Lv Xuliang*, Zeng Zhaoyang, Wen Xiaodi and Wen Liuqiang 

PLA University of Science and Technology, China 

Two methods are widely used to improve absorbing properties of the microwave 

magnetism-absorbing agent: mixing with the other material such as resistance 

carbon fiber absorbent, or wrapping the microwave magnetism-absorbing agent 

in that material. However, do these two methods coincide with each other? If not, 

which method should be used as better way to represent the absorbing properties of 

magnetism-absorbing agents? To answer these questions, both methods are carried out 

on the same magnetism-absorbing agents, of which the results are compared. Distinct 

difference between these measured results is found, and the possible reasons for the 

difference are also discussed. 

QO16 

Ordered magnetic arrays of cobalt SMM: properties and the 

relationship with crystal symmetry and SMM environment 

Milagros Tomas 1 , Cristina Saenz De Pipaon 2 , Elena Forcen-vazquez 2 , Isabel Mayoral 2 , 

Larry Falvello 3 , Javier Campo 2 and Fernando Palacio 4 * 

1 Instituto de Sintesis Quimica y Catalisis Homogenea (ISQCH), Consejo Superior de 

Investigaciones Cientificas and University of Zaragoza, Spain 

2 Instituto de Ciencia de Materiales de Aragon, Consejo Superior de Investigaciones 

Cientificas and University of Zaragoza, Spain 

3 Departamento de Quimica Inorganica and Instituto de Ciencia de Materiales de Aragon, 

Consejo Superior de Investigaciones Cientificas and University of Zaragoza, Spain 

4 Instituto de Ciencia de Materiales de Aragon (ICMA), Consejo Superior de 

Investigaciones Cientificas and University of Zaragoza, Spain 

The modulation of the magnetic properties of SMMs and their organization in extended magnetic arrays 

are, at the present, some of the top areas in the field of molecular magnetism for the implication in the 

improvement of the physical properties of the SMM and the potential use in devices such as for data 

storage. Few polymers of SMM have been structurally characterized in spite of the number of known 

SMM. [Co4citrate4]8- cubanes can behave as SMM.(1) We have reported recently(2) the union of 

these cubanes through “Co(H 2O) 2ETG” (ETG=ethylene glycol) bridges and the formation of anionic 

2D layers. These layers crystallize in the tetragonal system, P-421c space group, with counterions (Cs + 

or Rb + ), water and ETG molecules connecting the layers though electrostatic interactions and hydrogen 

bridges. The magnetic studies show the co-existence of two magnetic nets: the SMM net and the one 

formed by the bridged cobalt atoms and also shows the influence of the counterions in the layer magnetic 

properties. Two intriguing relaxation processes with different characteristics timescales are observed. 

Moreover, [Co4citrate4]8- cubanes can also organize in 3D, diamond-like structural arrays showing 

SMM magnetic behaviour below 6K with an energy barrier of 54K and magnetic ordering below 2.7K. 

1- M. Murrie, Chem. Soc. Rev. 2010, 39, 1986 -1995. 2- E. Burzuri, J. Campo, L. Falvello, E. Forcen-Vazquez, F. 

Luis, I. Mayoral, F. Palacio, Cristina Saenz de Pipaon, M. Tomas. Chem. Eur. J. 2011, 17, 2818-2822. 

QO17 

QO18 

QO19 


Enhancement of the refrigerant capacity in Gd 65Fe 20Al 10B 5 alloys by 

partial crystallization of melt-spun amorphous ribbons 

Jozef Marcin 1 , Zbigniew Sniadecki 2 , Jozef Kovac 1 , Peter Svec 3 , Bogdan Idzikowski 2 

and Ivan Skorvanek 1 * 

1 Institute of Experimental Physics SAS, Kosice, Slovak 

2 Institute of Molecular Physics PAS, Poznan, Poland 

3 Institute of Physics SAS, Bratislava, Slovak 

The magnetocaloric effect (MCE) is attracting a great deal of scientific interest because it is a basis of the 

environmentally friendly magnetic refrigeration technology. Among the recently developed magnetic 

refrigerant materials, the Gd(Fe,Mn)Al-based glassy alloys combine good magnetic entropy characteristics 

with sufficiently high effective magnetic moment per volume, which makes them promising candidates 

for magnetic refrigeration in the operating temperatures around 150 K [1,2]. In this work, we report on the 

beneficial effect of partial crystallization on magnetocaloric properties of melt-spun Gd 65Fe 20Al 10B 5 alloys. The 

magnetic entropy changes, ΔSm, were calculated from the magnetization versus applied field dependences 

measured in the temperature range from 5 to 390 K. The value of the maximum magnetic entropy change 

under 50 kOe for the Gd 65Fe 20Al 10B 5 ribbon reached 5.01 J/kg K at 185 K. The corresponding value of the 

refrigeration capacity, RC, determined as the area below the ΔSm peak with the integration limits at its half 

maximum is 647 J/kg. We have found that this value can be further enhanced by suitable heat treatment 

of melt-spun ribbons leading to a formation of hexagonal Gd particles with higher Curie temperature. The 

observed improvement is discussed in relation with two-phase character of partially crystallized samples. 

[1] S. Gorsse, B. Chevalier, G. Orveillon, Appl. Phys. Lett. 92 (2008) 122501 [2] Y.K. Fang, C.H. 

Lai, C.C. Hsieh, X.G. Zhao, H. W. Chang, W.C. Chang W.Li, J. Appl. Phys. 107 (2010) 09A901 

Chemical pressure effects on half-metallic properties in single crystals 

of A 2FeMoO 6 (A = Ca, Sr, and Ba) 

Akira Isayama* and Takao Sasagawa 


An ordered double perovskite oxide Sr 2FeMoO 6 has been predicted and widely studied 

as a half-metal, in which electrons with only one spin direction present at the Fermi 

level (100% spin polarization), above room temperature. In this study, in order to 

improve the half-metallic properties, the chemical pressure effects, through A-site 

substitution, on the magnetic and electronic properties have been examined using single 

crystalline samples of A2FeMoO 6 (A = Ca, Sr, and Ba) grown by the floating zone 

method. In the A = Ca crystal, every property related to the half-metallic performance 

was found to be degraded as compared with the A = Sr and Ba crystals: the saturation 

magnetization and the Curie temperature were significantly decreased, metallic 

conductivity became more than twice larger, and the spin polarization (evaluated by 

Andreev reflection spectroscopy) was reduced below 50%. From the results in the 

A = Sr and Ba crystals, it is suggested that the optimized half-metallic performance 

will be obtained in between these two compositions. Optical measurements were also 

performed to gain insight into the change of electronic structures with respect to the 

A-site substitution. 

Magnetic label field collector of biochip sensor 

Sunjong Oh, Brajalal Sinha, Jaein Lim and Chelgi Kim* 

Department of Materials Science and Engineering, Center for NanoBioengineering 

and Spintronics, Chungnam National University, Korea 

We have proposed a new method called stray field collector (SFC) of magnetic labels 

for signal enhancement in the magnetoresistive biosensors. The proposed design related 

to qualitative as well as quantitative detection of magnetic beads. The integration of 

SFC in magnetic sensor will increase the amount of stray field via the increase of active 

surface area. Therefore, this SFC may have great potential to improve the performance 

of magnetic biosensor. 

[1] Adarsh Sandhu, et al, “High efficiency Hall effect micro-biosensor platform for detection 

of magnetically labeled biomolecules,” Biosensors and Bioelectronics, 22, 2115-2120, 2007. 

[2] Guanxiong Li, et al, “Spin valve sensors for ultrasensitive detection of superparamagnetic 

nanoparticles for biological applications,” Sens Actuators A Phys., 126(1), 98-106, 2006. [3] W. 

Clark Griffith, et al, “Miniature atomic magnetometer integrated with flux concentrators,” Applied 

Physics Letters, 94, 023502, 2009. 


Poster Tuesday



QO20 

Cogging torque cancellation technique for dual rotor type motor using 

adjustment between outer and inner rotor magnet angle. 

Tae Won Jeong 1 , Hyun Rok Cha 1 *, Dae Yeong Im 1 , Kwang Heon Kim 2 and Hyoung 

Uk Nam 1 

1 Automotive components R&D group, korea institute of industrial technology, Korea 

2 Department of Electrical Engineering University of the Chonnam, Korea 

In this paper, we design the IPM motor and discuss the design method of double rotor permanent 

magnet motor for cancelling the cogging torque. According to downsizing the electric motor, high torque 

and power density are the most serious requirements for electric machines. Double rotor permanent 

magnet motor is proposed to solve the problem. But it has a large cogging torque that generates the 

large acoustic noise. A variety of techniques exist for reducing the cogging torque of conventional radial 

flux IPM machines. This paper introduces a new cogging torque minimization technique for radial flux 

multiple IPM motors. Optimization of the adjustment magnet angle between outer rotor and inner rotor 

which results in offset cogging torque and assessment of the effect on the maximum available torque 

using Finite Element Analysis (FEA) is investigated. In our experiments, Prototype dual rotor type 

motor has achieved the outer rotor and inner rotor cancellation of cogging torque by 70 percent. 

[1] R. Qu and T. A. Lipo, 'Dual-rotor, radial-flux, toroidally wound, permanent-magnet machines', 

IEEE Transactions on Industry Applications, Vol. 39, No.6, Nov/Dec 2003, pp.1655-1673. [2] R. 

Qu, and T. A. Lipo, 'Design and parameter effect analysis of dualrotor, radial-flux, toroidally wound, 

permanent-magnet machines', IEEE Transactions on Industry Applications, Vol. 40, No.3, May/ 

June 2004, pp.771-779 [3] R. Qu and T. A. Lipo, 'Sizing Equations and Power Density Evaluation 

of Dual-Rotor, Radial-Flux, Toroidally Wound, Permanent-Magnet Machines,' XVI <strong>International</strong> 

<strong>Conference</strong> on Electrical Machines, ICEM 200r, Cracow, Poland, Sept 2004. 

QO21 

A broadband circuit analog absorber based on printed dipole antenna 

Li Xiaopeng 1 , Cui Chuan'an 1 , Lv Xuliang 1 * and Lin Shaofeng 2 

1 Engineering Institute of Corps of Engineers,PLA University of Science and 

Technology, China 

2 Xi'an Communication Institute, China 

Based on the equivalent transmission line theory, a composite absorber with broadband 

planar array antenna is designed. The first layer is an array antenna, which uses 

printed dipole with balun feed as basic unit. The second layer a PIN diode array, 

which corresponded with antenna feeding units. The impedance match characteristic 

of the absorber can be adjusted by setting the microstrip balun. And the reflection 

characteristic of the absorber can be adjusted by adjusting the bias voltage of the PIN 

diode array. Simulated by electromagnetic simulation software HFSS, the results show 

that the absorber reflection coefficient is below -10dB at 3.5-15GHz.The experimental 

result, which replace PIN diodes with surface mount device resistors, is in good 

agreement with simulation data. 

QO22 

Effect of oxygen pressure to magnetism and transport properties of 

epitaxial Fe 3O 4 grown by molecular beam epitaxy 

Dang Duc Dung 1 , Wuwei Feng 2 , Duong Van Thiet 3 , Duong Anh Tuan 3 and Sunglae 

Cho 3 * 

1 Department of General Physics, School of Engineering Physics,Ha Noi University of 

Science and Technology,1 Dai Co Viet road, Ha Noi, Viet Nam 

2 Department of Physics, University of Ulsan, Ulsan 680-749,, Korea 

3 Department of Physics, University of Ulsan, Ulsan 680-749, Korea 

Fe 3O 4 is predicted to possess as half-metallic nature, ~ 100% spin polarization, and has a high Curie temperature 

and an ultrahigh room temperature magnetoresistance (MR) for tunneling magnetoresistance (TMR) junctions 

with Fe 3O 4 electrodes [1]. However, for the TMR junction, a highly conductive under layer and the sharp between 

interfaces are required because the poor conductivity and roughness of films may lead to a non-uniform current 

distribution [2]. In addition, the Verwey transition (TV, a first order metal-insulator transition) of 120 K in bulk 

Fe 3O 4 is still under controversy because many parameters such as orientation of substrate, buffer layer, thickness, 

pressure, and thermo-chemical treatment affect the TV [3, 4]. Epitaxial Fe 3O 4 films were grown on MgO(001) 

substrates via molecular beam epitaxy. The growth modes, magnetism, and transport properties of the thin films 

were strongly dependent on the oxygen pressure during film growth. The average roughness decreased from 1.021 

to 0.263 nm when the oxygen pressure was increased from 2.3x10-7 to 8.2x10-6 Torr, respectively. In addition, 

the saturation magnetic moment reduced as increasing the oxygen pressure during grown. Moreover, the Verwey 

transition in the Fe 3O 4 disappeared for a sample grown at a high oxygen pressure. 

[1] Z. Zhang et al., Phys. Rev. B 44, 13319 (1991). [2] P. H. Huang et al., J. Appl. Phys. 97, 10C311 (2005). [3] E. J. W. 

Verwey et al., Physica 8, 979 (1941). [4] A. R. Muxworthy et al., Geophys. J. Int. 140, 101 (2000), and reference therein. 


QO23 

Magnetism and transport properties of epitaxial Mn 5Ge 3 thin films on 

GaAs(001) and GaSb(001) 

Dang Duc Dung 1 , Doji Odkhuu 2 and Sunglae Cho 2 * 

1 Department of General Physics, School of Engineering Physics, Ha Noi University 

of Science and Technology,1 Dai Co Viet road,Ha Noi, Viet Nam 

2 Department of Physics, University of Ulsan, Ulsan 680-749, Korea 

The epitaxially ferromagnetic Mn 5Ge 3 thin films were grown on GaSb(001) and 

GaAs(001) substrates using molecular beam epitaxy. Our result revealed that the 

substrate facilitates to modify magnetic and electrical properties due to tensile strain 

effect. The Curie temperature was remained above 350 K for samples grown on 

GaAs(001), while was about 320 K for samples grown on GaSb(001). The anomalous 

Hall effect were observed up to 370 K and 320 K for films grown on GaAs(001) 

and GaSb(001), respectively, which are strong evidence for spin polarization. Our 

electronic calculation indicated that the difference in Mn-Mn bond length in Mn 5Ge 3 

modified the magnetization and spin polarization. The strains are promised to control 

both magnetic properties and spin polarization. 

QO24 

Current-driven domain wall motion in artificial magnetic domain structures 

Ke Wang 1 , Murali Krishnan Hari 1 *, Simon Bending 1 , Erhan Arac 2 , Del Atkinson 2 , 

Serban Lepadatu 3 , J S Claydon 3 and Chris Marrows 3 

1 Department of Physics, University of Bath, United Kingdom 

2 Department of Physics, University of Durham, United Kingdom 

3 School of Physics and Astronomy, University of Leeds, United Kingdom 

We report progress towards optimisation of artificial magnetic domain structures for efficient spin transfer torque 

domain wall (DW) motion [1]. Co/Pt multilayer samples have been sputtered on (100) Si/SiO 2 substrates and 

perpendicular magnetic anisotropy confirmed using polar magneto-optical Kerr effect (MOKE) measurements. 

The influence of the thickness of Co and Pt layers on the coercivity and switching behaviour was systematically 

investigated and the conditions established for realising well-suited structures with medium coercivity (~100 

Oe) and sharp switching fields [2]. Optimised Co/Pt multilayer films were lithographically patterned into 

nanowire devices for time-resolved extraordinary Hall effect (EHE) measurements. Our devices are based on 

50 W coplanar waveguides incorporating single and double Hall cross structures. The coercivity of the region 

surrounding the Co/Pt Hall crosses was reduced by local focussed ion beam (FIB) irradiation [3] allowing 

the controlled nucleation of domain walls at the edges of these regions by application of an appropriate field 

sequence. We describe polar MOKE experiments that show how DC currents lead to asymmetric switching of 

these artificial domains due to current-assisted DW motion across them. We will also present preliminary results 

of time-resolved EHE and MOKE measurements of current-driven DW motion in these structures. 

[1] O. Boulle et.al, Phys. Rev. Lett. 101, 216601 (2008); I.M. Miron, P.-J. Zermatten, G. Gaudin, S. Auffret, B. 

Rodmacq, and A. Schuhl, Phys. Rev. Lett. 102, 137202 (2009); L. San Emeterio Alvarez, K.Y. Wang, S. Lepadatu, S. 

Landi, S. J. Bending, and C. H. Marrows, Phys. Rev. Lett. 104, 137205 (2010) [2] K. Wang, M-C. Wu, S. Lepadatu, J. S. 

Claydon, C.H. Marrows, and S. J. Bending, J. Appl. Phys. 110, 083913 (2011). [3] A. Aziz et.al, J. Appl. Phys. 98, 

QO25 

The cellular uptake mechanism of SPIONs: an in-vitro study 

Yasmin Khan 1 and Radha Srinivasan 2 * 

1 Department of Life Sciences, Sophia College, Mumbai, India 

2 Department of Physics, University of Mumbai, India 

The Superparamagnetic Iron Oxide Nanoparticles of sizes ranging from 10-50 nm 

are being used in a large number of biological studies because of their peculiar 

characteristics of inducing local hyperthermia, MR imaging, specific targeting and 

drug delivery. An in-vitro study of the cytotoxicity and an understanding of the specific 

pathway of cellular uptake will enable manipulation of conditions for optimal cellular 

uptake of SPIONs for targeted therapy. The objective of the present study was to 

identify the endocytotic pathway through which the SPIONs are taken up by C6 glioma 

cells. The cells were pre-incubated with different concentrations of pharmacological 

inhibitors and then exposed to SPIONs for a few hours. The endocytosed particles were 

localized and quantitatively estimated using Perl's or Prussian Blue reaction. There 

was significant reduction in the uptake of SPIONs when incubated with the inhibitor 

indicating the uptake of nanoparticles is being inhibited.This reduction in SPION 

uptake was found to be dependent on the concentration of the inhibitors and also the 

nature of the inhibitors. By a systematic study of choosing various inhibitors, the data 

can be narrowed down to the final pathway that may be involved in the SPION uptake.

QO26 

Theoretical and experimental studies of valence states in Fe-Mo 

compounds 

Francisco Estrada 1 *, Reginaldo Mondragon 1 , Humberto Noverola 2 , Jaime Raul 

Suarez 3 , Martha Teresita Ochoa 1 , Francisco Espinosa 1 , Lorena Alvarez 1 , Ricardo 

Morales 4 , Jose Lemus 4 , Oracio Navarro 2 and Michel Avignon 3 

1 

Centro de Investigacion en Materiales Avanzados, S. C, Mexico 

2 

Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de 

Mexico, Mexico 

3 

Institut Neel, CNRS and Universite Joseph Fourier, France 

4 

Instituto de Investigaciones Metalurgicas, UMSNH, Mexico 

The half-metallic ferromagnetic double perovskite compound Sr 2FeMoO 6 is considered as an 

important material in view of its potential spintronic applications. It appears to be fundamental to 

understand the role of electronic parameters controlling the half-metallic ground state. In particular, 

half-metallic ferromagnetic compounds have been searched as a source of spin polarized currents. In 

this work, we study the valence states of cations in Fe-Mo based double perovskites from theoretical 

and experimental point of view. In the experimental case, we apply the electron energy-loss 

spectroscopy (EELS) technique. For transition metals, L2,3 edges of EELS are characterized by two 

sharp peaks, known as white lines. EELS experiments have shown that the change in valence states 

of cations introduces significant modification in the energy and shape of the white lines, leading to the 

possibility of identifying cation valence states. These results are compared with those coming from 

theoretical calculation using the Green functions and the renormalization perturbation expansion 

method. The theoretical model is based on a correlated electron picture with localized Fe-spins and 

conduction electrons interacting with the local spins via a double-exchange-type mechanism. 

QO27 

Structural modifications in magnetic MWCNT by 100 MeV SHI 

irradiations 

Sanjeev Gautam 1 , Keun Hwa Chae 1 , Jong Han Song 1 , Saji Augstine 2 , J.k. Kang 2 and K. 

Asokan 3 

1 

Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Korea 

2 

Material Science and Engineering, Korea Advanced Institute of Science and 

Technology (KAIST), Korea 

3 

Material Science Center, Inter-University Accelerator Center, New Delhi, India 

Carbon nanotubes (CNTs) possess unique mechanical and electronic properties suitable for 

fabricating the nano-scale building blocks of nanodevices [1]. One of the requirements for 

applications is to cut the CNT in small dimensions in the order of few nanometers. To this 

respect, we investigate the effect of heavy ion beams, namely, 100 MeV of O and Ni ion beam 

on CNT synthesized by chemical vapor deposition (CVD) technique[2]. The ion fluence 

selected for this study was 1e13 ions per cm 2 . High energy heavy ion irradiation was carried out 

at Inter-University Accelerator Centre, New Delhi, India. This paper reports the experimental 

results obtained from X-ray diffraction pattern and images of scanning electron microscopy 

(SEM) and transmission electron microscope (TEM) measured at Nano Materials Analysis 

Center, KIST, Korea. These results show that heavy ions can induce damage or cut in an 

ordered periodicity of few nanometers. Apart from above studies, we also carried out near-edge 

x-ray absorption spectroscopy investigations for electronic structure modifications. 

[1] E. Wohlfarth, in: G. Rado, H. Suhl (Eds.), Magnetism,Vol. 3 (Acad Press, New York, 1963). [2] 

Gautam S, Thakur P, Augustine S, Kang JK, Kim JY, et al. arXiv: 1111.5416v1 (Nov. 23 2011). 

QO28 

Magnetic and magneto-transport properties of (Mn 0.8, Zn 0.2) 1-xGa xFe 2O 4 

ferrites 

Hyo-jin Kim and Sang-im Yoo* 

Department of Materials Science and Engineering, Seoul National University, Korea 

A significant enhancement of low-field magnetoresistance (LFMR) could be achieved 

from polycrystalline samples of Ga 2O 3-doped Mn-Zn ferrites. For this study, the 

magnetic and magnetotransport properties of samples with two different nominal 

compositions of (Mn 0.8, Zn 0.2) 1-xGa xFe 2O 4 (x = 0.05, 0.1) were carefully investigated. 

The X-ray diffraction analyses revealed that all Ga 2O 3-doped Mn-Zn ferrites of the 

spinel structure were a pure phase without the second phase. By doping Ga 2O 3 to the 

pure Mn-Zn ferrite, the resistivity level was abruptly decreased over four orders of 

magnitude. The 5 mol% Ga 2O 3-doped Mn-Zn ferrite sample exhibited the LFMR ratio 

over 1.7 % at 300 K in 0.5 k Oe without appreciable increase in its resistivity. Detailed 

doping effects of Ga 2O 3 on the magnetic and maneto-transport properties of the Mn-Zn 

ferrite will be presented and discussed in this paper. 

QP01 

QP02 

QP03 

Effect of the external fields on SpinRAM switching time 

Mitsuhiro Shiomi* and Yoshinobu Nakatani 

Univ. of Electro- Communications, Japan 


Magnetic coupling at the CoO/Ni interface 

Sergiy Grytsyuk*, Fabrizio Cossu and Udo Schwingenschlogl 

Physical Sciences and Engineering, King Abdullah University of Science & 


We study the CoO/Ni interface. Since the lattice mismatch between Ni and CoO is 

21%, we use a large supercell for our first principles calculations which reduces the 

lattice mismatch to 0.8%. We investigate the structural, electronic, and magnetic 

properties of two interface configurations: (1) An O layer mediates the coupling 

between Ni and Co and (2) a direct Ni-Co contact. Our results indicate that the 

magnetization is reduced by 19% in the first case, while in the second case it increases 

by 100% as compared to bulk Ni. The magnetic moments obtained at the interfaces 

can be explained by the local environment of the interface atoms. In addition, we find 

effects of charge transfer between the interface atoms. 

Electronic, structural, and magnetic properties of O and Py deficient 

CoO/Py interfaces. 

Sergiy Grytsyuk* and Udo Schwingenschlogl 

Physical Sciences and Engineering, King Abdullah University of Science & 


The development of magnetic devices, which are based on coupling between 

ferromagnet and antiferromagnet (such as spin-valves), depends strongly on the 

interfacial magnetic structure. Since vacancies at the interface are expected to be 

important in determining the macroscopic properties of such systems, a quantitative 

determination of their influence on the interfacial magnetization is essential. We 

therefore investigate the CoO/Py interface (Py = Ni 80Fe 20, Permalloy). Py has a high 

permeability, low magnetostriction, and high anisotropic magnetoresistance. It is a 

good conductor for spin-majority electrons and poor conductor for spin-minority 

electrons. At the same time the Neel temperature of CoO is approximately room 

temperature and its magnetocrystalline anisotropy is high. Since the lattice mismatch 

between Py and CoO is about 20%, we use a large supercell for our first principles 

calculations which reduces the lattice mismatch to less than 0.1%. We describe the 

dependence of the interface magnetization on the amount of O and Py vacancies and 

address the exchange bias. 

Spin current driven magneto resistive random access memory (SpinRAM) is one of the 

candidates for the next generation non volatile memory. There are still many problems 

to realize it. One of the problems is the switching speed. The method for fast switching 

with lower current is required. Field assist switching is one way. In this paper, the 

effect of the DC and AC external field on the switching time of the SpinRAM with 

perpendicular anisotropy is investigated by simulation. The effect of the thermal noise 

is also investigated. From the results without thermal noise, the switching time was 

decreased by both of the DC and AC field. However, AC field is effective for fast 

switching compared with DC field. From the results with thermal noise, the switching 

time was not decreased by weak DC field and more strong DC field was required to 

reduce the switching time. On the other hand, the switching time was decreased by 

weak AC field. From these results, it was found that AC field is more effective than 

DC field to reduce the switching time. This study was supported by New Energy and 

Industrial Technology Development organization (NEDO) partly. 


Poster Tuesday


QP04 


A study on the perpendicular toggle-MRAM system by using new 

combined hysteresis method for high Gb/Chip 

Hyuk Won and Gwan Soo Park* 

School of Electrical Engineering, Pusan National University, Korea 

Conventional (toggle) MRAM has unlimited read/write endurance but has a low 

capacity than flash technology. A lot of work has been done for the commercialization 

of submicrometer MRAM in recent years. A low-power 1Mb MRAM with copper 

interconnects and cladding layer, and about 35 ns access and cycle times tested in the 

previous work show the potential of this technology. A new multibit MRAM cell of 

toggle switching type has been reported and also, a heat interaction investigation in 

thermally assisted MRAM has been reported. In this paper we presents a new design 

that has advantages conventional MRAM on injected current and cell size. It is pole 

type perpendicular MRAM (PTP MRAM). PTP MRAM uses perpendicular magnetic 

field in order to change the state of the free layer in a perpendicular magnetic tunnel 

junction (pMTJ). In this paper, new efficient algorithm to combine two models are 

presented and tested. This approach reduces computing time and gives more precise 

results because the result of 2 dimensional Preisach model becomes an initial values of 

3 dimensional micromagnetics. 

QP05 

Room temperature exchange bias in the multiferroic BiFe 0.8Mn 0.2O 3 

nanoparticles with a core-shell structure 

S M Yusuf* and P K Manna 



The compound BiFeO 3 shows a multiferroic character. We have shown that the 

BiFeO 3-based compound viz. BiFe 0.8Mn 0.2O 3 nanoparticle system exhibits other 

important multifunctional behaviour as well. We have observed the exchange 

bias effect, in the form of a shift in the field-cooled hysteresis loop, and a training 

effect in a dc magnetization study. From transmission electron microscopy, neutron 

diffraction, thermoremanent magnetization, and isothermoremanent magnetization 

measurements, the nanoparticles are found to be core-shell in nature, consisting of 

an antiferromagnetic (AFM) core, and a two-dimensional diluted AFM (DAFF) shell 

with a net magnetization under a field. Our calculation using the Binek’s model on the 

training effect yields a theoretical understanding of the observed loop shift which arises 

entirely due to an interface exchange coupling between core and shell. The intrinsic 

contribution of the DAFF shell to the total loop shift is zero. The present study is useful 

to understand the origin of exchange bias in other DAFF-based systems as well. The 

significantly high value of the exchange bias field (~ 0.16 kOe), observed at room 

temperature, in the present nanoparticle system has made it a blue-eyed candidate for 

the next generation advanced nano-technological applications in the area of magnetic 

storage devices. 

QP06 

Magnetic and Transport Properties of Mn 3-xGa/MgO/Mn 3-xGa 

Magnetic Tunnel Junctions: A First-Principles Study 

Zhaoqiang Bai, Yongqing Cai, Lei Shen, Guchang Han and Yuanping Feng* 

Physics, National University of Singapore, Singapore 

Magnetic and transport properties of Mn 3-xGa/MgO/Mn 3-xGa (0≤x≤1) magnetic tunnel 

junctions are studied using first-principles approach based on density functional theory 

and non-equilibrium Green's function. Perpendicular magnetization, of which the 

magnetic anisotropy energy reaches more than 1 meV/unit-cell, is confirmed to be 

energetically favoured by both Mn 2Ga and Mn 3Ga thin films. Furthermore, despite 

high spin-polarization at Fermi energy for both these compounds as reported, our 

transport calculation shows considerable disparity in the transmission behaviour 

between Mn 2Ga/MgO/Mn 2Ga(001) and Mn 3Ga/MgO/Mn 3Ga(001) magnetic tunnel 

juctions: huge optimistic tunneling magnetoresistance ratio ~ 1000% for the former, 

and nevertheless, no tunneling magnetoresistance effect absolutely for the latter. This 

phenomenon is attributed to the spin symmetry filtering effect of the MgO spacer. 

On this premise, Mn 3-xGa compounds with low Mn concentration are predicted to be 

promising candidate materials to serve as the electrodes of spin-transfer toque devices 

in 


QP07 

Concomitant memory effect in CrO 2/Cr 2O 3 core-shell nanorods 

Ashish Chhaganlal Gandhi and Sheng Yun Wu* 

Department of Physics, National Dong Hwa University, Taiwan 

The concomitant memory effects are intensively studied in last few decades and are mostly observed in 

spin-glass and superparamagnetic systems [1-3]. The memory effects were observed in the interacting 

permalloy nanoparticles [4] and isolated nanoparticles [5], providing us interesting information 

about the investigation of nature of the low temperature phase. In the present work, we succeeded 

in preparing CrO 2/Cr 2O 3 core-shell nanorods using the chemical vapor deposition method. The 

magnetic properties of CrO 2/Cr 2O 3 core-shell nanoparticles can be treated as a ferromagnetic-CrO 2core 

and antiferromagnetic-Cr 2O 3O-shell compound coupled by an exchange interface coupling and 

raised magnetic anisotropy energy between them. The evolution of core shell magnetization triggered 

by an applied magnetic field at 1.8 K was observed, and a core-shell anisotropic energy model was 

applied to simulate the competition between the surface magnetic anisotropy and exchange interface 

coupling. Memory and aging effects were observed and overcame the superparamagnetic limit [3] up 

to sufficiently high temperature which makes it an important candidate in magnetic data storage, as 

an application. Acknowledgments: This research was supported by a grant from the National Science 

Council of Taiwan, the Republic of China, under Grant Number NSC-100-2112-M-259-003-MY3. 

[1] M. Sasaki, P. E. Jonsson, H. Takayama, and H. Mamiya; Phys. Rev. B 71, 104405 (2005). [2] 

Malay Bandyopadhyay and Sushanta Dattagupta; Phys. Rev. B 74, 214410 (2006). [3] V. Skumryev, 

S. Stoyanov, Y. Zhang, G. Hadjipanayis, D. Givord and J. Nogues Nature 423, 850 (2003). [4] 

Young Sun, M. B. Salamon, K. Garnier and R. S. Averback; Phys. Rev. Lett. 91, 167206 (2003). [5]M. 

Sasaki, P. E. Jonsson, H. Takayama, and P. Norblad, Phys. Rev. Lett. 24, 139701 (2004). 

QP08 

High resolution probes for magnetic force microscope 

Xiaoxi Liu*, Shinsaku Isomura and Akimitsu Morisako 

Department of Information Engineering, Shinshu University, Japan 

Magnetic force microscopy is a convenient and efficient method to detect magnetic 

domain structures in magnetic recording media or nano-magnet. In this work, we 

present a simple process to fabricate probes for magnetic force microscopy with 

sub-ten nanometer resolution. A thin layer of FeCo is deposited onto commercially 

available silicon probes by a facing targets sputtering system. We choose facing targets 

sputtering because this kind of system can minimize the damage of the films from high 

energy particle bombardment. The radius of the curvature of the probes is depended on 

the FeCo film thickness. High resolution scanning microscope image show the radius 

of the curvature is less than 20 nm for a 20 nm thick FeCo coating. Magnetic force 

microscopy images show our probes have resolution better than 10 nm. Due to the high 

magnetic moment of FeCo, we can get magnetic contrast for FeCo coating as thin as 

10 nm. Micromagnetic simulations indicate than the formation of a magnetic vortex at 

the apex of the probe is crucial for the high resolution. 

QP09 

Selective magnetization switching by microwave assistance for layered 

magnetic pillar 

Terumitsu Tanaka 1 *, Yuto Otsuka 1 , Yoshitoki Furomoto 1 , Kimihide Matsuyama 1 and 

Yukio Nozaki 2 

1 ISEE, Kyushu University, Japan 

2 Department of Physics, Keio University, Japan 

Microwave assisted magnetization reversal (MAMR)[1] is a promising candidate for 

future magnetic recording technology. In MAMR, magnetization switches only when DC 

and microwave fields are applied to magnetic material at particular microwave frequency. 

Utilizing such a feature, possibility of selective switching of magnetizations was estimated by 

micromagnetic calculation for realizing 3-dimensional magnetic recording. In the calculation, a 

magnetic pillar composed of 3 layered materials was considered. Pillar diameter is 11 nm, and 

thickness of the 1st, 2nd, and 3rd layers are 5, 13, and 14 nm, respectively. Hk 1 (= 24kOe), Ms 1 

(= 600 emu/cc), Hk 2 (= 13kOe), Ms 2 (= 400 emu/cc), and Hk 3 (= 6 kOe), Ms 3 (= 800 emu/cc) 

represent anisotropy fields and saturation magnetizations of 1st, 2nd, and 3rd layers. These values 

give sufficient thermal stability indices (greater than 60 at 300 K) for every layer. Magnetization 

switching probabilities equal to 1 were obtained at particular microwave frequencies for every 

layer; selective switching occurs at 1st, 2nd, and 3rd layer when microwave frequency is 8, 

18, and 28 GHz, respectively. In this calculation, the single pillar has shown to store 3 bits 

information. These results imply MAMR has a potential in 3-dimensional magnetic recording. 

[1] J. -G. Zhu, X. Zhu and Y. Tang, IEEE Trans. Magn. 44, 125 (2008)

QP10 

Thermal effect in microwave assisted magnetization reversal 

Yoshitoki Furomoto, Yuto Otsuka, Terumitsu Tanaka* and Kimihide Matsuyama 

ISEE, Kyushu University, Japan 

Microwave assisted magnetization reversal (MAMR)[1] has potential application 

in future magnetic recording. The critical curves for MAMR in a single-domain 

particle is theoretically estimated by Bertotti et al.[2, 3], which well explains steady 

state magnetization switching at 0 K and the equations allow three solutions “stable”, 

“unstable” and “saddle”. In this study, MAMR properties in a single-domain particle 

were simulated solving the Landau-Lifshitz-Gilbert equation taking account of 

temperature elevation due to ferro-magnetic resonance. Magnetization switching 

probability at 400 K widely distributes in HMW in unstable region. The critical values 

of HMW are greater than that at 0 K nevertheless thermal activation decreases energy 

barrier height. This implies stochastic thermal fields reduce efficiency in MAMR in 

the region. On the other hand, thermal activation gives 25-35 % of reduction in critical 

value of HMW in stable region, which is achievable for recording head of recent hard 

disk drive. 

[1] J. O. Artman, S. H. Charap, and D. J. Seagle, IEEE Trans. Magn. MAG-19, 1814 (1983). [2] G. 

Bertotti, C. Serpico, and I. Mayergoyz, Phys. Rev. Lett. 86, 724 (2001). [3] S. Batra and W. Scholz, 

IEEE Trans. Magn. 44, 3392 (2008). 

QP11 

Stable magnetization switching with microwave assistance for 

exchange coupled composite grain 

Terumitsu Tanaka*, Yoshitoki Furomoto, Yuto Otsuka and Kimihide Matsuyama 


Microwave assisted magnetization reversal (MAMR)[1] is a promising candidate for 

future magnetic recording. Li et al. proposed ECC medium for solving the potential 

problems in microwave power and frequency for MAMR[2]. Bertotti et al. theoretically 

analyzed MAMR process taking a single spin for example[3], which showed the LLG 

equation can be written in the other forms[4]. The equation allows three solutions 

“stable”, “unstable” and “saddle”. However, the theory cannot be applied to exchange 

coupled composite (ECC) structured grain. In this study, distributions of the regions 

defined by the three solutions were estimated for an ECC grain. In the ECC grain, 

stable switching region, in which magnetization reversal modes are hardly affected by 

disturbance such as thermal fluctuation, distributes at lower fields region comparing 

to that for the single spin particle. This result means that stable magnetization reversal 

occurs with relatively weak magnetic fields even for ultra high Hk materials assigned 

to future high density recording. 

[1] J. -G. Zhu, X. Zhu and Y. Tang, IEEE Trans. Magn. 44, 125 (2008). [2] S. Li, B. Livshitz, H. N. 

Bertam, M. Schabes, T. Schrefl, E. E. Fullerton and V. Lomakin, Appl. Phys. Lett. 94, 202509 (2009). 

[3]Giorgio Bertotti , Claudio Serpico , and Isaak D. Mayergoyz , Phys. Rev. Lett. 86, 724 (2001) [4] 

Werner Scholz and Sharat Batra , J. Appl. Phys.103, 07F539 (2008) 

QP12 

Low-temperature epitaxial growth of FePt on glass substrates for 

ultrahigh magnetic recording densities 

Thanassis Speliotis 1 *, George Giannopoulos 1 and Dimitris G Niarchos 2 

1 Institute of Materials Science, NCSR DEMOKRITOS, Greece 

2 Institute of Materials Science, NCSR Demokritos, Greece 

Magnetic FePt alloy thin film with ordered L10 structure is a promising material 

for perpendicular magnetic recording (PMR) application, duo to its huge uniaxial 

magnetocrystalline anisotropy (Ku), high saturation magnetization (Ms), high coercivity (Hc) 

and outstanding corrosive resistance. Ku value of L10 FePt is about 7 MJ/m3 which sets the 

superparamagnetic limit of L10 FePt as small as 2.8 nm. In PMR application the preferred 

orientation has to be transformed into (001) that makes the [001]-axis perpendicular to the 

film. Accordingly, developing an effective way to prepare L10 FePt (001) thin film with 

perpendicular magnetic anisotropy at low order-disorder transformation temperature is the 

concern of first priority.Although excellent properties can be obtained in sputtered FePt on 

single crystal MgO (001) much effort is needed to obtain PMR properties of sputtered FePt 

films on glass substrates. A number of underlayers have been used to induce texture such 

as CrRu, MgO and very recently TiN. Here we report a systematic study of the system { 

Hoya glass/CrRu/MgO/FePt/Ta} and through optimization of layer thickness, deposition 

temperature and sputtering power , we achieved perpendicular anisotropy, coercivity in 

excess of 1 T and deposition temperatures around 400 0C. 

Supported by the project TERAMAGSTOR of the EU 

QP13 

QP14 

QP15 


Controlling nanostructure in FePt films: Co-sputtering of FePt and C 

or SiO 2 

George Giannopoulos*, Thanassis Speliotis and Dimitris G Niarchos 

Institute of Materials Science, NCSR DEMOKRITOS, Greece 

Achieving magnetic recording densities in excess of 1Tbit/in2 requires not only 

perpendicular media with anisotropy larger than 7 MJ/m3, which makes the FePt alloy 

as the best choice , but also narrow distribution and small sizes below 10 nm for a 

reduced S/N ratio along with high thermal stability. Previous work has shown that the 

L10 FePt grain size can be controlled by alloying FePt with materials such as C, Ag, 

and insulator like AlOx, MgO act to segregate and magnetically decouple the FePt 

grains. Better results were obtained with C with respect to the uniformity of grains and 

SiO 2 with respect to the shape, but far from optimization. We present our results by cosputtering 

FePt with C or SiO 2 (up to 30 vol % ) on MgO (001) single crystal substrates 

at 350 and 500 0C. With C or SiO 2 addition we achieved the grain size reduction, the 

shape control and isolated structure formation, by producing continuous films with 

high uniformity and narrow main size distribution down to 10 nm. This also reflected 

in the variation of coercivity as a function of the additional phase, thus giving us a 

possibility to simultaneously control the coercivity and the S/N ratio. 

Retention time under currents and magnetic fields in a CoFeB/MgO 

perpendicular magnetic tunnel junction 

Michihiko Yamanouchi*, Hideo Sato, Katsuya Miura, Shoji Ikeda, Fumihiro 

Matsukura and Hideo Ohno 

Center for Spintronics Integrated Systems, Tohoku University, Japan 

CoFeB/MgO based magnetic tunnel junctions with perpendicular anisotropy (p-MTJs) 

[1,2] have been investigated extensively because of their potential for realization 

of nonvolatile logic circuits and random access memories [3-6]. For ensuring their 

nonvolatility, effects of current (I) and magnetic field (H) on cumulative distribution of 

retention time (tr) of magnetization direction in the recording layer should be clarified. 

Theoretical expression for the distribution under I and H has been proposed [7]. However 

it has not been compared with experimental results in CoFeB/MgO p-MTJs. In this work, 

we investigated tr under I and perpendicular H in the same CoFeB/MgO p-MTJ with 40 

nm in diameter and compared it with the theoretical expression [7]. It was found that the 

cumulative distribution of tr under I (H) can be fitted well with the theoretical expression 

in the range of tr = 30 μs - 100 s (5 - 960 s). From tr under I (H), thermal stability factor 

is evaluated to be 44 (39), which agrees well with previous results in similar MTJs [1,4]. 

This work was supported by the FIRST program from JSPS. 

[1] M. Endo et al., Appl. Phys. Lett. 96, 212503 (2010). [2] S. Ikeda et al., Nature Mater. 9, 721 

(2010). [3] D. C. Worledge et al., Appl. Phys. Lett. 98, 022501 (2011). [4] H. Sato et al., Appl. Phys. 

Lett. 99, 042501 (2011). [5] H. D. Gan et al., Appl. Phys. Lett. 99, 252507 (2011). [6] J. J. Nowak et 

al., IEEE Magn. Lett. 2, 3000204 (2011). [7] Z. Li et al., Phys. Rev. B 69, 134416 (2004). 

Thermal diffusion in magneto-optic collinear volumetric hologram 

memory 

Seungmin Baek, Hiroyuki Sakurai, Pang Boey Lim and Mitsuteru Inoue 

Toyohashi University of Technology, Japan 

Collinear holography memory is a good candidate of the next generation of optical 

memory. Recently we have investigated the magneto-optical recording with thick 

polycrystalline magnetic garnet films by collinear holography. Rewritable properties 

and shift multiplexing of the magnetic holograms were confirmed experimentally. 

However, it has still high noise level in the retrieved image. We investigated the 

suppression method of thermal diffusion in magnetic hologram recording numerically 

and experimentally. The recording principles of the magnetic holography are 

basically similar with thermomagnetic recording. The interference patterns with 

signal information are recorded as magnetization patterns. Due to thermal diffusion 

in recording process, the interference patterns were in disorder. It could be shown in 

results of the low diffraction efficiency and high noise level. Numerical simulation 

result shows the influence of thermal diffusion was suppressed with below 10-9 second 

of laser pulse width. Experimental result with two-beam interferometer also shows 

over 200 % higher diffraction efficiency recorded by 50 ps pulse width laser than 25 ns 

one in high spatial frequency range. 


Poster Tuesday


QP16 


Resolution of magnetic garnet films for magneto-optic collinear 

volumetric hologram memory 

Seungmin Baek, Hiroyuki Sakurai, Naoto Sagara, Pang Boey Lim and Mitsuteru 

Inoue 

Toyohashi University of Technology, Japan 

Collinear holography memory is promising optical memory of the next generation. 

The photopolymer materials have received much attention because of high sensitivity, 

high dynamic range and low costs as recording materials. On the other hands, 

magnetic garnet films have the advantage of rewritable, no necessity of shading, and 

no shrinkage, as compared to photopolymer which has write-once property. In this 

study, we fabricated the different grain sizes of magnetic garnet films by annealing 

time. The fundamental properties of samples and the SNR of the retrieved images with 

single hologram were investigated. Bi-substituted iron garnet films (3.3 μm thick) were 

fabricated by RF magnetron sputtering on SGGG substrates. Samples were annealed 

at 750 °C in air for several annealing time. The retrieved images were evaluated by 

collinear holographic system. The resolution of magnetic recording media was related 

with the grain size of magnetic recording media. The results show SNR of the retrieved 

image was improved by reduction of the grain size. 

QP17 

Room temperature ordering perpendicular magnetic anisotropy L11 

CoPtCu thin film on glass substrate 

Chiuan-fa Huang 1 , Long-jie Li 1 , An-cheng Sun 1 *, Fu-te Yuan 2 , Jen-hwa Hsu 2 , S. N. 

Hsiao 3 and H. Y. Lee 3 

1 Department of Chemical Engineering & Materials Science, Yuan-Ze University, Taiwan 

2 Department of Physics, National Taiwan University, Taiwan 

3 National Synchrotron Radiation Research Center (NSRRC), Taiwan 

Rhombohedral unit cell of L11 CoPt films have attracted a lot of attention due to their large magnetocrystalline 

anisotropy (Ku ~ 107 erg/cm3) as well as relatively low ordering temperature (~ 200 oC) [1,2]. The addition of 

Cu significantly improves the alignment of c-axis, chemical ordering and enhances perpendicular coercivity (Hc┴) 

of L11 CoPtCu phase deposited at 350 oC [3-5]. In this study, Co 27Pt 50Cu 23 films with a Pt underlayer were 

deposited on glass substrates at room temperature (RT) to 500 oC by sputtering. The thickness of the film was 5 

nm. Interestingly, the high perpendicular magnetic anisotropy (PMA) was observed when the film was deposited 

at RT. Furthermore, PMA was maintained until the substrate temperature (Ts) exceeded 450 oC. Hc was largely 

enhanced from 0.25 to 2.6 kOe when Ts was increased from RT to 350 oC. Beyond 350 oC Hc started to decline. 

The appearance of high PMA suggests that the ordered L11 structure is formed in CoPtCu film even prepared at 

room temperature. This finding promotes the applications of L11 CoPtCu films in future perpendicular magnetic 

recording and spintronic device. The variation of phase structure and microstructure with Ts will be presented. 

[1] S. Iwata, S. Yamashita, S. Tsunashima, IEEE Trans. Magn. 33 (1997) 3670. [2] F.T. Yuan, A.C. Sun, J.H. Hsu, Scripta Materialia 

62 (2010) 762. [3] F-T. Yuan, A-C. Sun, J-H. Hsu, C.S. Tan, P.C. Kuo, W.M. Liao, H.Y. Lee J. Appl. Phys. 108 (2010) 113909. [4] 

F-T. Yuan, A-C. Sun, J-H. Hsu, C.S. Tan, P.C. Kuo, W.M. Liao, H.Y. Lee J. Appl. Phys. 109 (2011) 07B714. [5] Fu-Te Yuan, L. J. Li, 

Jen-Hwa Hsu, S. N. Hsiao, H. Y. Lee, Hsi-Chuan Lu, Sea-Fue Wang, C. Y. Shen, and An-Cheng Sun, J. Appl. Phys. (accepted) 

QP18 

Magnetic anisotropy and chemical ordering in Fe-Pt films prepared by 

low-temperature growth technique 

Nyun Jong Lee 1 , Jae Young Ahn 1 , Yu Jeong Bae 1 , Dominique Eyidi 2 *, Anny Michel 2 * 

and Tae Hee Kim 1 * 

1 Department of Physics, Ewha Womans University, Korea 

2 Departement de Physique et Mecanique des Materiaux, Institut Pprime, UPR 3346, 

CNRS-Universite de Poitiers-ENSMA, F86962 Futuroscope-Chasseneuil cedex, 

France 

We investigated the chemical ordering and perpendicular magnetic anisotropy (PMA) 

in L1 0 FePt and L1 2 FePt 3 films. FePt films with different thickness of 35 and 70 A were 

grown, at the substrate temperature T s = 300 °C by MBE co-evaporation and layer-by-layer 

growth, onto a MgO layer deposited on Si wafer. In order to optimize the growth of highly 

ordered FePt(001) films in conditions of low-temperature fabrication, the influence of a 

thin (001)-oriented fcc Pt buffer layer on the c-axis oriented texture was explored by high 

resolution TEM and X-ray diffraction (XRD). Our results showed a strong enhancement 

of PMA without high-temperature annealing, for 35 A thick FePt films, while a decrease in 

PMA was observed for L1 2 FePt 3. By introducing a small percentage of Boron into the L1 2 

ordered FePt 3, enhanced structural ordering was seen in XRD. However, no significant 

change of magnetic properties was observed, in contradiction with the expectation to 

induce PMA by altering the chemical ordering in FePt 3 L1 2 phase. In this work, we discuss 

the origin of spin reorientation transition phenomena related to our results. *corresponding 

authors : taehee@ewha,ac,kr; Anny.S.Michel@univ-poitiers.fr 


QP19 

Nanoscale ion beam etching process for reducing damage and leakage 

path of magnetic tunnel junction 

Daehong Kim 1 , Bongho Kim 1 , Sungwoo Chun 1 , Hyungyu Kim 1 , Seonjun Choi 1 and 

Seung-beck Lee 2 * 

1 Department of Electronic Engineering, Hanyang University, Seoul, Korea 

2 Institute of Nano Science and Technology, Hanyang University, Seoul, Korea 

To integrate ultrahigh density spin-transfer torque magnetic random access memory (STT-MRAM), 

a stable process to pattern metallic magnetic tunnel junctions (MTJs) is required. [1] We investigated 

the ion milling process to fabricate the MTJ cells for perpendicular STT-MRAM application with 

minimized redeposition layer by a gradational stage tilting process and low damage of MTJ by 

reduced beam supply voltage. The hard mask used a 30nm diameter negative electron-beam resist 

patterned by electron beam lithography. Thereafter, ion milling process was conducted through 

regulation of beam/accelerate supply voltage and stage tilting angle. We found that the highest 

MTJ slope angle was attained at the stage tilt angle of 80° which was the angle of the incident ion 

flux to the stage surface. However, high angle etching resulted in a thick redeposition layer. For 

reducing redeposited layers, we have utilized variable-angle multi-step ion milling process. Also 

for reduced MTJ sidewall damage by high beam supply voltage, reduced the beam supply voltage. 

Consequently, sidewall damage of MTJ layer was minimized. The TMR ratio and the resistance of 

the fabricated MTJ cells were 13% and 1kΩ respectively. Our results showed the potential of using 

optimized ion milling for fabricating nanoscale MTJs for ultrahigh density STT-MRAMs. 

[1] M. Hosomi, H. Yamagishi, T. Yamamoto, K. Bessho, Y. Higo, K. Yamane, H. Yamada, M. Shoji, H. 

Hachino, C. Fukumoto, H. Nagao,and H. Kano: IEDM Tech. Dig., 2005, p. 459. 

QP20 

A new planer patterned media with anti-ferro / ferro transformation 

Hiroaki Ono and Hiroyuki Awano 

Toyota Technological Institute Information Storage Material Lab., Japan 

For next-generation HDD, the planer patterned media which need neither pattern 

etching nor smoothing processing is attractive.1),2) As a proposal of the new media, 

ferro-magnetized patterned area in the flat anti-ferro-magnetized layer has been 

prepared by using near field laser irradiation or masked ion implantation. On the ferromagnetized 

area, required data can be recorded. We prepared several kinds of TbFeCo/ 

Rh/TbFeCo tri-layers. When the Rh thickness is some period, strong anti-ferromagnetic 

coupling (AFC) is realized. In the combination, Rh thickness of the 1st peak 

of the anti-ferro-coupling was 0.45nm. Since the thickness of the TbFeCo was thick 

and Rh thickness was very thin, the transformation from AFC to FC can be control 

easily. The coercive force was 1.5kOe. Also the Hc can be designed by controlling Tb 

concentration. For example, in this case, the transformation temperature was 100 °C.It 

is also easy to control by changing TbFeCo thickness. Moreover, the patterned media 

can be applied as a write once HDD, since it is impossible to change recorded area for 

the ferro-magnetized area. 

1) I. Nakatani,T. Takahashi,M. Hijikata, T. kobayashi, K. Ozawa, and H. Hanaoka: Japanese Patent 

No.888363, filed in June 1989. 2) T.Kato et al., J. Appl. Phys., 105, 07C117 (2009) 

QP21 

Topology optimization of perpendicular magnetic recording head 

considering magnetic saturation effect 

Park Soon Ok* 

Yonsei University Graduate school, Korea 

The topology optimization method is an attractive scheme for magnetic device design 

because an initial conceptual design can be obtained without any prototype model. However, 

studies concerning the three-dimensional magnetic device design by topology optimization 

are rare. Even more, topology optimization of magnetic systems has been generally 

accomplished by using the two-dimensional finite element method while the nonlinear 

saturation effect of the material property between magnetic field strength and magnetic flux 

density has not been fully considered. This study proposes a topology optimization technique 

of the three-dimensional design as well as the two-dimensional design based on the density 

method considering the nonlinear saturation effects. The proposed method makes it possible 

to provide useful and practical process for magnetic system design and may lead to improved 

design with light system weight. The proposed method is applied to the optimization 

problem of a magnetic recording system. During the design process, the reluctivity of 

magnetic material is changed according to the nonlinear B-H relationship during magneto 

static analysis. The sensitivity analysis and the update of design variables are accomplished 

by the adjoint variable method and the sequential linear programming, respectively. 

Topology optimization; finite element analysis; magnetic saturation effect; three dimensional 

design; density method; adjoint variable method.

QP22 

The effect of capped layer thickness on switching behavior in coupled 

granular/continuous media 

Weimin Li 1 , Jun Ding 1 * and Jianzhong Shi 2 

1 

Department of materials science and engineering, National University of Singapore, 

Singapore 

2 

Data Storage Institute, Agency for Science, Technology and Research (A*STAR), 

Singapore 

Coupled granular/continuous (CGC) media (a CoPtCrB continuous layer exchange coupled to a granular 

oxide CoPtCr: SiO 2TiO 2Ta 2O 5 layer) exhibited improvement of SNR, thermal stability and switching 

field distribution (SFD)[1, 2]. TEM images together with intrinsic SFD for capped structure are studied to 

investigate the mechanism of the SFD reduction in CGC media. We find out that in the bottom part, CoPtCr 

magnetic grains are separated by nonmagnetic oxide grain boundaries. The amorphous grain boundary 

phase in the granular layer propagates to the top surface of the capped layer. The grain size increases with 

capped layers thickness. A critical capped thickness exists. At thinner capped thickness, capped layer inherits 

structural irregularity from the granular layer, while at thicker layer, the upper portion of capped layer is less 

influenced by the granular layer. ReportedΔH (M, ΔM) method[3] is used to calculate intrinsic SFD. Both 

intrinsic and macroscopic SFD decrease linearly with capped layer thickness. As we know, the intrinsic 

SFD is due to the local variations of the grains properties. The reduction of macroscopic SFD is caused by 

homogenous grains and uniform exchange coupling at thicker capped layer. 

1. H. S. Jung, E. M. T. Velu, S. S. Malhotra, U. Kwon, D. Suess and G. Bertero, Magnetics, IEEE Transactions on 43 (6), 2088- 

2090 (2007). 2. H. Nemoto, I. Takekuma, H. Nakagawa, T. Ichihara, R. Araki and Y. Hosoe, Journal of Magnetism and Magnetic 

Materials 320 (22), 3144-3150 (2008). 3. A. Berger, B. Lengsfield and Y. Ikeda, Journal of Applied Physics 99 (8), 08E705-706 (2006). 

QP23 

The effect of magnetic field on FePt nanoparticles during annealing 

process 

A. Khajehnezhad 1 , S. A. Sebt 1 , R. S. Dariani 2 and M. Akhavan 3 * 

1 

Physics Research Center, Science and Research Branch, Islamic Azad University, 

Tehran, Iran, Iran 

2 

Physics, Alzahra University, Tehran, Iran 

3 

Physics, Sharif University of Technology, Iran 

FePt, L10 nanocrystals are expected as one of promising candidates for the magnetic recording media with 

ultrahigh densities. The 3nm FePt NPs have been synthesized by the polyol method and analysed by TEM 

analysis. The composition of the films was estimated to be approximately Fe 62.40Pt 37.60 by EDXS. Surface of 

Si and SiO 2 wafers have been covered by FePt nanoparticles and heated in 600°C for 1h to form L10 phase 

nanoparticles [1]. FE-SEM and XRD analyses show uniform surface distributions of FePt, L10 nanoparticles. 

The SiO 2 [2] substrate prevents nanoparticles from coalescence during annealing and prevents them from 

growth [3], hence, causing their size not to become more than 40nm. SiO 2 wafer is more suitable than Si wafer 

in separating the nanoparticles, which may be due to oxygen of surface bonding with nanoparticles. Presence 

of 30mT magnetic field controls the size of nanoparticles around 25nm, which can be related to the reduction 

of random mobility in magnetic field and causes the nanoparticles to self-organize directionally. The larger 

I(001)/I(111) for perpendicular magnetic field indicates that the easy axis of nanoparticles is aligned in this 

direction [4]. The magnetic field also controls the surface distribution during heating process. 

1. S. Sun, Adv Matter 18, 393-403 (2006). 2. T. Ichitsubo, S. Tojo, T. Uchihara and E. Matsubara, Phys. 

Rev. B 77, 094114 (2008). 3. Y. C. Wu, L. W. Wang, and C. H. Lai, Appl. Phys. Lett. 93, 242501 (2008). 4. M. 

I. J. Beale, N. G. Chew, M. J. Uren, A.G. Cullis, and J.D. Benjamin, Appl. Phys. Lett. 46, 86(1985). 

QP24 

Novel soft lithography technique for fabrication of Ni nanodots for use 

as bit patterned media 

Shivaraman Ramaswamy 


Magnetic disk drive technology has successfully reduced the size of multi-grain bits 

to ~30 nm, and there are intensive industrial efforts to shrink the bit size further. This 

work reports the development of a cheap, scalable polymer template lithography 

technique of fabricating large arrays of magnetic nanostructures towards use as bit 

patterned media, one of the prominent next generation data storage technologies. 

The technique has been standardized and physical properties such as bit sizes, pitch 

sizes and the storage densities have been calculated. Critical magnetic properties 

such as magnetization reversal have also been studied and discussed to ascertain the 

plausibility of its use in futuristic high density magnetic data storage devices 

[1] Park. S, Lee. D.H, Xu. J, Kim. B, Hong. S. W, Jeong. U, Xu. T, and Russell. T.P, 2009, 

“Macroscopic 10-Terabit-per-Square-Inch Arrays from Block Copolymers with Lateral Order,” 

Science, vol. 323, pp. 1030-1033. [2] Kikitsu. A, Kamata. Y, Sakurai. M and Naito. K, 2007, 

“Recent progress of patterned media,” IEEE Transactions on Magnetics, vol. 43,pp. 3685-3688. [3] 

Speliotis. D, 1984,'Media for high density magnetic recording', IEEE Transactions on Magnetics, 

20, 5, 669 - 674. 

RA01 

RA02 

RA03 


Magnetic resonance and ferroelectricity of BaTi 1-xFe xO 3 

Dianta Ginting 1 , N. V. Dang 2 , V. D. Lam 2 , S. C. Yu 1 and T. L. Phan 1 * 

1 Phyisch, Bk 21, chungbuk national university, Korea 

2 Institute of Materials Science, Vietnamese Academy of Science and Technology, 

Hanoi, Viet Nam 

BaTiO 3 is known as an excellent candidate for multiferroics. In this work, we present magneticresonant 

and ferroelectric properties of polycrystalline BaTi 1-xFe xO 3 ceramics (0 ≤ x ≤0.12) prepared 

by conventional solid-state reaction. Measurements have been based on an X-ray diffractometer, 

electron spin resonance (ESR) spectroscopy, and Precision Premier-Radiant. X-ray diffraction 

patterns reveal the tetragonal-hexagonal phase transformation as increasing Fe-doping content. ESR 

spectra prove that many samples to be ferromagnetic, excepting for the x = 0.02-0.06 samples, which 

are paramagnetic. Such the results are in good agreement with the previously report on the magnetic 

behavior. Room-temperature P-E hysteresis loops of BaTi 1-xFe xO 3 reveal that with increasing Fe 

concentration, the feature of ferroelectric P-E loops changes in the shape to the paraelectric regime, 

indicating the decrease in ferroelectricity. Consequently, the values of the remnant polarization Pr and 

the coercive field Ec gradually are also decreased. Keywords: Fe-doped BaTiO 3; Magnetic phase 

separation; Ferroelectricity *Electronic mail: ptlong2512@yahoo.com Phone: 

Daniel Khomskii, Physics,2.20 (2009) W. Eerenstein, N.D. Mathur & J.F. Scott, Nature 442(17) (2006) N.V Dang, 

Thanh, L.V.Hong, V.D Lam, The-Long Phan, Applied Physics 110, 043914, (2011). QIU Shen-Yu, LI Wang, LIU 

YU, LIU GUi Hua, WU Yi-Qiang, Chen Nan, Trans. Nonferrous Met.Sos. China 20,1911-1915(2010). Manfred 

Fiebig, J. Phys. D: Apply.Phys.38, R123-R152. S.Angappane, G Rangarajan, and K.Sethupathi, J. Apply. 

Phys.93,8334 (2003).F. Lin, D. Jiang, X. Ma, and W. Shi, Physica B 403, 2525 (2008). S. Ray, P. Mahadevan, S. 

Mandal, S. R. Krishnakumar, C. S. Kuroda, T. Sasaki, T. Taniyama, and M. Itoh, Phys. Rev. B 77, 104416 (2008). 

Growth of high pure BiFeO3 single crystals 

Kai Feng 1 , Jun Lu 2 * and Yicheng Wu 1 

1 

Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 

100190, China, China 

2 

State Key Laboratory of Magnetism, Technical Institute of Physics and Chemistry, 

Chinese Academy of Sciences, Beijing 100190, China, China 

BiFeO 3(BFO) is a heavily beaten compound in recent publications. BFO exhibits 

simultaneous polar and magnetic order at room temperature, promising important 

applications, but growth of pure BFO single crystals is really a great challenge. To 

grow extremely pure BFO single crystals, we have systematically investigated Bi 2O 3- 

Fe 2O 3 pseudo-binary system from the long-term crystal growth experiments, high 

performance powder X-ray diffraction analysis and high temperature differential 

thermal analysis instrument. The peritectic transition temperature of BFO was 

determined to be 852±5˚C and Other typical characteristic temperatures in Bi 2O 3-Fe 2O 3 

pseudo-binary phase diagram were reevaluated. It has been found that purity of grown 

BFO single crystals depends greatly on crucible materials. When suitable kind of 

crucibles were used, extremely high pure BFO single crystals could be easily obtained 

with maximum size above one centimeter. 

[1] J. Lu et al., Eur. Phys. J. B, 75(4), 451-60(2010) (as cover story) [2] J. Lu et al., J. Cryst. 

Growth,318, 936-41(2011) [3] J. Lu et al., A method of growing centimeter pure BiFeO3 single 

crystals, Chinese Patent, 201110252660.5 

Structural, electrical and magnetic properties of La-doped BiFeO 3 

ceramics. 

M. Roy, S. Jangid, S. K. Barbar and Indu Bala Thakur 

Department of Physics, M. L. Sukhadia University, Udaipur, India 

Polycrystalline ceramic samples of Bi 1-xLa xFeO 3 (x=0.0, 0.1 and 0.2) have been 

prepared by standard solid state reaction method using high purity oxides and 

carbonates. The structure and formation of the compounds have been checked by X-ray 

diffraction followed by energy dispersive X-ray microanalysis (EDAX) techniques. 

There is a good agreement between observed and calculated X-ray diffraction patterns 

obtained by performing the Rietveld refinement with a structural model using the noncentrosymmetric 

space group R3c. The lattice parameters have been refined but the 

over all structure remained the same. The microstructural studies have been carried 

out using scanning electron microscopy. The dc conductivity of all the samples has 

been measured and their activation energies were calculated from logσ vs 103/T 

curves. Vibrating sample magnetometer (VSM) has been used to study the magnetic 

behaviour of the compounds. It has been observed that with the increase of substitution 

concentration of La, the insulating behaviour of the materials have been improved 

and showing the antiferromagnetic to weak ferromagnetic behaviour. The results are 

discussed in detail. 


Poster Tuesday

Poster Thursday 


RA04 

In situ X-ray absorption spectroscopy study on BaTiO 3 

J.-s. Lee* and C.-c. Kao 

SSRL, SLAC National Accelerator Laboratory, USA 

Ferroelectric systems are under intensive study for both the point of view of 

fundamental materials physics and the potential applications such as memories, sensors, 

and transducers. The Ti 4+ (d0-ness) systems which are the generally well known 

ferroelectric as form ATiO 3 structure (A=Ba and Pb), inter alia, have been extensively 

investigated. To understand this system, both of structural and electronic investigations 

must be completed together. Structurally, Ti ions in the TiO 6 octahedra are moved 

along the applied electric (E)-field, resulting in a symmetry lowing. However, we still 

do not understand much about a change in the electronic structure between Ti 3d and 

O 2p states. Although the soft x-ray spectroscopy study at the oxygen absorption edge 

that is regarded as a good approach for exploring the electronic structure, such study 

accompanies an experimental difficulty; electron motion distortion under in situ E-field 

condition. In this work, we introduce an approach for overcoming such difficulty in 

conventional x-ray absorption spectroscopy (XAS) measurement. By looking at the O 

K-edge XAS of BaTiO 3 via a fluorescence yield, we studied electronic structure and 

reveal that the observed spectra features are related with the structural changes under 

the applied E-field. 

RA05 

Chiral skyrmions and magnetic bubbles in multiferroic materials 

Xiuzhen Yu 1 *, Y. Tokunaga 1 , S. Seki 2 , Y. Kaneko 3 , S. Ishiwata 2 , M. Mostovoy 4 , N. 

Nagaosa 5 and Y. Tokura 6 

1 

The Institute of Physical and Chemical Research, Japan 

2 

University of Tokyo, Japan 

3 

Japan Science and Technology Agency, Japan 

4 

University of Groningen, Netherlands 

5 

University of Tokyo, The Institute of Physical and Chemical Research, Japan 

6 

University of Tokyo, The Institute of Physical and Chemical Research, JST, Japan 

Nanometric chiral skyrmions and magnetic bubbles have been successfully realized in multiferroic 

materials Cu 2OSeO 3 and Sc-doped barium ferrite by means of Lorentz transmission electron microscopy. 

Under the normal magnetic fields, chiral skyrmions with a topological number of -1 and a unique chirality, 50 

nm in diameter, emerge in a non-centrosyemmetric helimagnet Cu 2OSeO 3. In analogy with the transition 

from a helical spin structure to chiral skyrmions, a normal magnetic field turns the magnetic stripes into 

a bubble lattice with a positional order and random chiralities in a hexaferrite BaFe 0.79Sc 0.16Mg 0.05O 19 

with uniaxial anisotropy. By systematically investigating the dependences of magnetic configurations on 

magnetic field, temperature and sample thickness, we reveal the differences between the spin textures of 

chiral skyrmions and magnetic bubbles. First, the magnetic bubbles determined by the ratio of dipolar and 

exchange interactions show strong size dependence on magnetic field and sample thickness. The chiral 

skyrmions induced by Dzyaloshinskii-Moriya interaction, however, show less size dependence on the 

external factors. Second is a difference in chirality. The chiral skyrmions have a unique chirality determined 

by the crystal chirality, while magnetic bubbles have two opposite chiralities, resulting in a variety of 

zoological magnetic structure with varying external magnetic field. 

RA06 

Studies on Bi 1-xLa xFeO 3 crystals in pulsed high magnetic fields 

Masashi Tokunaga 1 , Mitsuru Akaki 2 , Hideki Kuwahara 2 , Kengo Oka 1 and Takumi 

Kihara 1 



BiFeO 3 is known as the unique material that shows multiferroic nature at room temperature [1,2]. 

Application of high magnetic fields to this material induces a magnetic transition accompanied by a 

significant change in the electric polarization [3-5]. Although the occurrence of this transition is explained 

in the framework of the Ginzburg-Landau theory, in detail study is highly desirable to understand the 

microscopic origin of the magnetoelectric effects in this material. In this work, we synthesized crystals 

of Bi 1-xLa xFeO 3 with using the flux method, and studied their magnetic and dielectric properties in 

pulsed magnetic fields up to 55 T. Early experiments on the polycrystalline samples showed that partial 

substitution of La for Bi reduces the magnetic field needed to cause the magnetic transition [6]. Our 

isothermal magnetization measurements showed that the transition field at 4.2 K changes from 18 T to 15 

T by La substitution. Our dielectric study revealed that the electric polarization shows significant change 

accompanied with this magnetic transition. Therefore, the phenomena observed in BiFeO 3 are reproduced 

in the reduced field scale in the La substituted system, which enables us more systematic studies to clarify 

the microscopic origin of the magnetoelectric effects associated with the magnetic transition. 

[1] J. Wang et al., Science 299, 1719 (2003). [2] G. Catalan and J. F. Scott, Adv. Mater. 21, 2463 

(2009). [3] Yu. F. Popov et al., JETP Lett. 57, 69 (1993). [4] A. M. Kadomtseva, et al., JETP Lett. 

79, 571 (2004). [5] M. Tokunaga et al., J. Phys. Soc. Jpn. 79, 064713 (2010). [6] G. Le Bras et al., 

Phys. Rev. B 80, 134417 (2009). 


RA07 

Enhanced magnetic properties of Ni-doped BiFeO 3 compounds 

Y. J. Yoo 1 , J. S. Park 1 , J. H. Kang 2 , J. Kim 3 , B. W. Lee 3 , M. S. Seo 4 and Y. P. Lee 1 * 

1 Physics, Hanyang University, Korea 

2 Nano & Electronic Physics, Kookmin University, Korea 

3 Physics, Hankuk University of Foreign Studies, Korea 

4 Division of Materials Science, Korea Basic Science Institute, Korea 

The structure and the magnetic properties of polycrystalline BiFeO 3 and BiFe 0.95Ni 0.05O 3 

bulk ceramic compounds, which were prepared by solid-state reaction and rapid sintering, 

were investigated. High-purity Bi 2O 3, Fe 3O 4 and NiO powders were mixed with the 

stoichiometric proportions, and calcined at 450°C for 24 h to produce BiFe 1-xNi xO 3. The 

crystalline structure of samples was investigated at room temperature by using a Rigaku 

Miniflex powder diffractometer. The field-dependent and the temperature-dependent 

at high temperatures magnetization measurements were performed with a vibratingsample 

magnetometer. The temperature-dependent magnetization at low temperatures 

was analyzed with Quantum Design superconducting quantum-interference-device 

(SQUID) magnetometer. The x-ray diffraction study demonstrates the compressive stress 

due to the Ni substitution at the Fe site. The lattice constant of BiFe 0.95Ni 0.05O 3 is smaller 

than of BiFeO 3 because of the smaller ionic radius of Ni 3+ than that of Fe 3+ . The fielddependent 

magnetization of BiFe 0.95Ni 0.05O 3 exhibits a clear hysteresis loop at 300 K. The 

magnetic properties of BiFe 0.95Ni 0.05O 3 were improved at room temperature because of the 

existence of structurally compressive stress. The zero-field-cooled temperature-dependent 

magnetization reveals that the magnetic transition temperature and the magnetic moment 

of BiFe 0.95Ni 0.05O 3 are higher than those of BiFeO 3. 

RA08 

Magnetic modulation of electrical impedance in Bi-doped 

La 0.7Sr 0.3MnO 3 

Sujit Kumar Barik, M Aparnadevi and Ramanathan Mahendiran* 

Physics, National University of Singapore, Singapore 

In recent years, magnetic control of dielectric polarization in multiferroics and 

magnetoelectrica has become a topic of considerble interest. Dielectric studies in these 

materials are often done using an impedance analyzer in the frequency range f = 10 

to 10 kHz. As the frequency increase, dieletric permitivity decreses. Here, we show 

that an interesting phenomenon occurs in MHz range in Bi doped La 0.7Sr 0.3MnO 3. 

With increasing freqeuncy of the ac current or ac voltage, both in- and out-of phase 

compnents of electrical impedance show an abrupt increase that is accompanied by a 

peak around the Curie temperature. The peak decreases in magnitude and is suppressed 

in a field of 1 kOe. This results in a huge ac magnetoresistance (30-35 % for H = 1 

kOe) and magnetoreactance (= 30-40 %). The origin of the magnetoreactance is not 

necessarity due to change in capacitance but but it is suggested to magnetoindutance 

effect, which has not been seriously considered so far. The combination of huge ac 

magneoresistance and magnetonductance in a single material provides multifunctional 

capabilities. Results from our studies are compared to magnetocapacitance behavior 

found in BiMnO 3[1] 

[1] T. Kimura, S. Kawamoto,I. Yamada, M. Azuma, M.Takano, Y. Tokura, Phys. Rev. B 2003, 67, 

R180401 2003 

RA09 

Theoretical study of PCAR measurement with d-wave 

superconductors. 

Hiroyuki Ohtori 1 and Hiroshi Imamura 2 * 

1 Univ. of Tsukuba, NRI-AIST, Japan 

2 NRI-AIST, Japan 

High spin polarization ferromagnetic metals are essential for creating high 

performance spintronics devices, therefore it is important to estimate the value of 

spin polarization quickly and efficiently. Point contact Andreev reflection (PCAR) 

spectroscopy is a powerful method for measuring spin polarization of ferromagnetic 

metals. However, most PCAR measurement were performed at very low temperatures, 

around 1.5 K, since the conventional s-type superconductor is used. If we use high- 

Tc superconductors, PCAR measurement can be performed at higher temperature. In 

this study, we theoretically analyze the Andreev reflection in the ferromagnetic metal 

(FM) / insulator (I) / d-wave superconductor (dS) junctions. The superconducting 

gap in momentum space is not uniform in the d-wave superconductor, therefore 

the conductance suppression due to the insulator is affected by the difference of the 

Fermi wave number between the ferromagnetic metal and superconductor. Especially, 

in the case of d x2-y2 model, we found that the bias voltage at which the normalized 

conductance of the FM/I/dS junction drops is expressed as a function of the exchange 

field of the ferromagnetic metal.

RA10 

T C Evolution of Bulk and Optical Spectra of Nanocolloidal Fe-doped 

Manganate CaMn 1-xFe xO 3 (x = 0, 0.01, 0.03, 0.05) 

Huyen-yen Duc Pham, Duc-thang Pham, Nam-nhat Hoang* and Duc-tho Nguyen 

Faculty of Technical Physics and Nanotechnology, Vietnam National University, 

University of Engineering and Technology, Viet Nam 

Recently, the effect of magnetic reversal at low magnetic field was observed with the 

multiferroic Fe-doped CaMnO 3 [Sol. Stat. Commun. 142 (2007) 525]. We report here the 

optical behaviors of this class of compounds (CaMn 1-xFe xO 3, x = 0, 0.01, 0.03, 0.05) which 

were prepared by using traditional ceramic method with parent oxides as precursors. The 

analysis of structure showed the predominant orthorhombic phase with slight increased 

cell constants according to doping content (from 3.743 to 3.746 Å). The investigation of 

the Raman spectra also agreed with the increased Mn-O bond length according to doping, 

therefore suggested the weakening of ferromagnetic exchange between Mn 3+ and Mn 4+ 

cations (exactly, from 0.61 to 0.52 eV). This weakening also developed together with 

the reduction of Curie temperature (T C) (from 155 to 135 K), the shifts of infra-red (IR) 

absorption maxima towards the longer wavelengths and the narrowing of band-gaps (from 

0.45 to 0.14 eV). The absorption spectra also showed a clear absorption line near 1.2 eV 

which is characteristic for Fe, and is composed mainly from 3d electron transition with a 

change in spin. 

PACS number: 75.47.Lx; 75.50.Ee; 74.25.Fy; 75.30.Kz 

Keywords: perovskite, manganate, structure, optical 

RA11 

Evidence of magnetic phase separation in LuFe2O4 Julie Bourgeois 1 , Gilles Andre 2 , Sylvain Petit 2 , Julien Robert 2 , Maria Poienar 3 , Jerome 

Rouquette 3 , Erik Elkaim 4 , Maryvonne Hervieu 1 , Christine Martin 1 , Antoine Maignan 1 

and Francoise Damay 2 

1 

Laboratoire CRISMAT, CNRS UMR 6508, 6 bvd Marechal Juin, 14050 CAEN CEDEX, France 

2 

Laboratoire Leon Brillouin, CEA-CNRS UMR 12, 91191 GIF-SUR-YVETTE CEDEX, France 

3 

Institut Charles Gerhardt, UMR CNRS 5253, Place Eugene Bataillon, cc1503, 34095 MONTPELLIER 

CEDEX 5, France 

4 

Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin BP 48, 91192 GIF-SUR-YVETTE CEDEX, France 

The magnetic properties of a polycrystalline sample of multiferroic LuFe 2O 4 [1] have been investigated 

by means of magnetization measurements combined with neutron scattering, between 1.5 and 300K 

[2]. Magnetic Bragg peaks appear below T N = 240K, and can be indexed using two propagation vectors, 

corresponding to either a ferromagnetic or an antiferromagnetic stacking of the iron bilayers. The magnetic 

arrangement in the ab plane follows a 1:2 pattern, which obeys the charge ordering one observed in 

transmission electron microscopy [3]. Neutron inelastic scattering data confirm the strong easy-axis 

single-ion anisotropy of the iron spin in its trigonal environment, of about 8 meV at 5 K. Modeling of the 

diffraction data, based on a CO-type modulation of the spin ordering, shows coexisting magnetic phases 

with opposite signs of the intra-bilayer interaction, corresponding to two distinct magnetic transition 

temperatures. Coexisting antiferromagnetic and ferrimagnetic phases, along with the enlarged axial 

magnetic anisotropy, are necessary to describe the macroscopic magnetic properties of this compound. 

[1] N. Ikeda et al., Nature (London) 436, 1136 (2005) [2] J. Bourgeois et al., submitted to Phys. Rev. 

B (2012) [3] J. Bourgeois et al., to appear in Phys. Rev. B (2012) 

RA12 

Magnetoelectric effect in mechanically mediated structure of TbFe 2, 

Pb(Zr,Ti)O 3, and nonmagnetic flakes 

Yin-gang Wang* and Ke Bi 

Nanjing University of Aeronautics and Astronautics, China 

For most investigations on layered ME composites with excellent ME effect compared 

to single phase materials and multiphase bulk composites, the classical structure is 

constructed layer by layer through interface bonding. In this work, the proposed ME 

structure is made up of two magnetostrictive TbFe 2 alloys, one piezoelectric PZT 

ceramic and two nonmagnetic glass flakes. When an external ac magnetic field Hac is 

applied along the length direction of magnetostrictive TbFe 2 flakes, the TbFe 2 flakes 

will produce an extensional strain. The strain then transfer to the PZT flake because 

of the end parts of PZT and TbFe 2 flakes bonded with glass slides in a vertical plane. 

Due to the piezoelectric effect, the PZT flake will induce a charge output. The interface 

between magnetostrictive and piezoelectric phases is not required to achieve ME 

coupling. Increasing H dc from zero, α E,31 increases linearly until a maximum value is 

reached at 350 Oe, and then decreases subsequently. With further increase in Hdc, 

α E,31 reaches a maximum value, and then decreases subsequently. There are several 

resonance peaks at 200 Oe and 1



RA16 

Enhancement of multiferroic properties of solid state prepared La 

doped BiFeO 3. 

Suresh P and Srinath S* 

School of Physics, University of Hyderabad, India 

BiFeO 3 (BFO) has generated widespread interest since it is a room-temperature 

multiferroic. La xBi 1-xFeO 3 (x= 0.05-0.4) are prepared through solid state reaction 

method. X-ray diffraction for x ≤ 0.15 shows R3c and for x> 0.15 the structure 

changes to Pbnm. The percentage of these phases present is estimated through Rietveld 

analysis. Raman spectra for x ≤ 0.15 exhibit 8 peaks (4A+4E modes). There is no 

shift in Raman modes indicating that La substitutes Bi in BFO. The dielectric constant 

increases and leakage current decreases with x. The enhanced polarization may be due 

to the distortion of the crystal lattice with La doping. With increase in La doping the 

T N decreases. The magnetization (M) decreases up to 250 K and increases on further 

cooling indicating the spin reorientation. A cusp in M-T is observed close to 50 K 

indicating the spin glass behavior. M-H loops do not saturate even for field up to 6 T. 

With La doping, H C and the magnetization increases dramatically in comparison to 

x=0. Both Hc (~ 1.6 T) and Mr (0.27 emu/g) have maximum values for x =0.2 at 5 K. 

The increase in the magnetic parameters is attributed to the break in the spin cycloid 

structure. 

(1) H. Fukamura et.al. J. Magn.Magn. Mater. 310, e367 (2007) (2) Manoj K. Singh et.al. Phys. Rev. 

B. 77, 144403 (2008) 

RA17 

Magnetostructural coupling at the metal-insulator transition in 

YBaCo 2O 5.5 as seen by synchrotron x-ray diffraction and absorption 

Jessica Padilla-pantoja, Javier Herrero-martin, Carlos Frontera and Jose Luis Garciamunoz 

Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Spain 

In LnBaCo 2O 5.5 (Ln: lanthanide) cobaltites Ln and Ba cations order in alternating planes along the 

c-axis yielding an ordered arrangement of CoO 5 pyramids and CoO6 octahedra. The presence of two 

local environments for Co may be at the origin of proposed Co spin-state changes whose interplay 

with the structural and electronic changes at metal-insulator transitions (MIT) are currently attracting 

much attention [1-5]. We present a study of the magnetic, structural and thermoelectric properties of 

YBaCo 2O 5.5 as a function of temperature. Our results evidence the presence of three magnetic transitions 

with a strong magnetostructural coupling. We have used synchrotron x-ray powder diffraction to show 

that the Pmmm orthorhombic structure transforms (on cooling) into a monoclinic (P112/a) phase 

below T MI ~ 295 K by doubling the a-axis [6]. Concomitantly a ferromagnetic moment appears and 

the Seebeck coefficient is enhanced. A further cooling leads to the successive appearance of Co AFM 

structures (T N1 ~ 267 K, T N2 ~ 231 K), the crystal structure becoming again orthorhombic. Finally, we 

present temperature dependent soft x-ray absorption data at the Co L 3 edge. They discard the possibility 

of a high to low spin state change in Co ions at octahedral sites across the MIT [7]. 

[1] A. Maignan et al., J. Solid State Chem. 142, 247 (1999). [2] E. Suard et al., Phys. Rev. B 61, R11871 

(2000). [3] C. Frontera et al., Phys. Rev B 74, 054406 (2006). [4] V.P. Plakhty et al., Phys. Rev. B 71, 

214407 (2005). [5] M. Soda et al., J. Phys. Soc. Jpn. 72, 1729 (2003). [6] J. Padilla-Pantoja et al., Phys. 

Rev. B 81, 132405 (2010). [7] J. Padilla-Pantoja et al., J. Appl. Phys. 111, 234291 (2012) (In press). 

RA18 

Magnetic field dependence of dielectric properties in LuFe 2O 4 

Takashi Kambe*, Yukimasa Fukada, Tomoko Nagata and Naoshi Ikeda 

Physics, Okayama university, Japan 

The multiferroic properties in LuFe 2O 4 are of interest, in which contains equal amount 

of Fe 2+ and Fe 3+ in triangular lattice. This material shows a ferri-magnetic transition at 

240K and three-dimensional charge ordering at around 320K. The dielectric property 

of this material is suggested with a valence fluctuation process of iron ions in the polar 

charge ordered domain. Here we report a magnetic field variation of the dielectric 

constant of single crystal LuFe 2O 4, and discuss with the valence fluctuation process of 

iron charges in the magnetic domain wall. 


RA19 

Pressure studies of LaAgSb 2 utilizing new integrated pressure cell 

Sven Friedemann 1 *, Zhou Feng 1 , Takao Ebihara 2 , Christophe Thessieu 3 and F Malte 

Grosche 1 


2 Department of Physics, Shizuoka University, Shizuoka 422-8529, Japan 

3 easyLab Technologies Ltd., Earley Gate, Whiteknights Road, Reading, RG6 6BZ, 

United Kingdom 

RA20 

Crystal & Magnetic structure studies of doped BiFeO 3 multiferroic 

compound 

Seongsu Lee 

Neutron Science Division, KAERI, Korea 

Multiferroics, materials combining multiple order parameters, offer an exciting way of coupling 

phenomena such as electronic and magnetic order. The coexistence of different order parameter 

permits potential applications in information storage, spintronics, and magnetic or electric field 

sensors. The perovskite BiFeO 3(BFO) is known to be antiferromagnetic below the Neel temperature 

of 640 K and ferroelectric with a high Curie temperature of 1100 K. According to the previous 

doping studies of BFO, it is likely that non-stoichiometry and second-phase formation are the factors 

responsible for leakage current in BFO. It has been suggested that oxygen nonstoichiometry leads 

to valence fluctuations of Fe ions in BFO, resulting in high conductivity. To reduce the large leakage 

current of BFO, one attempt is to make donor-doped BFO compounds. In this study, we have tried to 

generate the new multiferroric material functioning on at room temperature. The candidate systems 

are BiFeO 3+ BaMnO 3 and BiFeO 3+ BaTiO 3. These system have been fabricated by a solid-state 

reaction method and flux method, respectively. The crystal and magnetic structure of these systems 

are studied using XRD and neutron powder diffraction as functions of temperature. We will discuss 

the magnetic and electric property of new multiferroic system working on at room temperature. 

1. T. Choi, S. Lee, Y. J. Choi, V. Kiryukhin, and S-W. Cheong Science 324, 63 (2009) 2. Junghwan 

PARK, Sang-Hyun LEE, Seongsu LEE, Fabia GOZZO,Hiroyuki KIMURA, Yukio NODA, Young Jai 

CHOI, Valery KIRYUKHIN, Sang-Wook CHEONG, Younjung JO, Eun Sang CHOI, Luis BALICAS, 

Gun Sang JEON, and Je-Geun PARK Journal of the Physical Society of Japan 80, 114714(2011) 

RA21 

WITHDRAWN 

The analysis of structure, magnetic and ferroelectric properties of Ba1 xBixTi0.95Fe0.05O3 Widi Yansen 1 , Kadek Juliana Parwanta 1 , Jaeyeong Kim 1 , Min Gyu Kang 2 , Chong Yun 

Kang 2 and Bo Wha Lee 1 * 

1 

Physics, Hankuk University of Foreign Studies, Korea 

2 

Physics, Korea Institute of Science and Technology, Korea 

The multiferroic material is a material which shows more than one primary ferroic order parameter 

simultaneously and can be made by introducing the magnetic impurities into ferroelectric material 

[1]. BaTiO 3 is known as a classical ferroelectric material, whereas the Fe-doped BaTiO 3 is reported 

to have a magnetic ordering. Although the Fe doping can induce the ferromagnetism in BaTiO 3, 

the ferroelectricity of this material is suppressed. In this report, we analyze the structure, magnetic 

and ferroelectric properties of Ba 1-xBi xTi 0.95Fe 0.05O 3 (0 ≤ x ≤ 0.05). XRD results indicate that the 

tetragonal phase is merged with the hexagonal phase for x < 0.05. At x = 0.05, the pure tetragonal 

phase is observed. The magnetic field dependence of magnetization at room temperature for x 

= 0 shows a kind of antiferromagnetism. Introducing 2 % Bi doping, it shows the ferrimagnetic 

properties. However, with the 5 % doping of Bi, the ferrimagnetic loop is disappeared and 

becomes paramagnetic. It suggests that the superexchange between Fe 3+ ions in octahedral 

and pentrahedral sites associated with oxygen vacancy produces the ferromagnetism [2]. The 

ferroelectric hysteresis loop with low leakage current is only observed for x = 0.02. These results 

indicate that the multiferroic properties are observed in Ba 0.98Bi 0.02Ti 0.95Fe 0.05O 3 sample. 

[1] Y. Shuai, S. Zhou, D. Burger, H. Reuther, and I. Skorupa, J. Appl. Phys. 109, 084105 (2011). [2] F. 

Lin, D. Jiang, X. Ma, and W. Shi, J. Magn. Magn. Mater. 320, 691-694 (2008).

RA22 

Spin dynamics of multiferroic BiFeO 3 single crystal 

Jaehong Jeong 1 , E. A. Goremychkin 2 , T. Guidi 2 , K. Nakajima 3 , Gun Sang Jeon 4 , Shin-ae Kim 5 , S. 

Furukawa 6 , Yong Baek Kim 6 , Seongsu Lee 5 , V. Kiryukhin 7 , S-w. Cheong 7 and Je-geun Park 1 * 

1 FPRD Department of Physics & Astronomy, Center for Strongly Correlated Materials 

Research, Seoul National University, Seoul 151-747, Korea 

2 ISIS Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX, United Kingdom 

3 Neutron Science Section, MLF Division, J-PARC Center, Tokai, Ibaraki 319-1106, Japan 

4 Department of Physics, Ewha Womans University, Seoul 120-750, Korea 

5 Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353, Korea 

6 Department of Physics, University of Toronto, Toronto M5S 1A7, Canada 

7 Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers 

University, Piscataway NJ 08854, USA 

Multiferroic compounds are one of most challenging topics in the condensed matter physics [1] not only for 

its fundamental importance but also for huge future applications. Although several systems are known to have 

multiferroic behavior, there are few multiferroic materials that have both magnetic and ferroelectric transition 

temperatures above room temperature. BiFeO 3 is probably the only exception with Neel temperature at T N=650 

K and Curie temperature at T C=1100 K [2]. In order to understand the spin dynamics of BiFeO 3, we have carried 

out inelastic neutron scattering experiments on ten co-aligned single crystals of BiFeO 3 using AMATERAS 

beamline at J-PARC and MERLIN beamline at ISIS. In particular, we used a so-called sample rotation method on 

MERLIN to map out the full three-dimensional spin wave [3]. We have also calculated the spin wave dispersion 

using Heisenberg Hamiltonian with two exchange parameters between the nearest and next nearest neighbors. 

A Dzyaloshinskii-Moriya term that arises from the spiral magnetic structure of BiFeO 3 was also examined. By 

carefully examining the AMATERAS and MERLIN data, we could find, for the first time, the full spin wave 

dispersion of BiFeO 3 and determine the exchange parameters that are consistent with the experimental results. 

1) S-W. Cheong and M. Mostovoy, Nature Materials 6,13 (2007) 2) I. Sosnowska et al., J. Phys. C: Solid 

State Phys. 15, 4835 (1982) 3) Jaehong Jeong et al., Phys. Rev. Lett. 108, 077202 (2012) 

RA23 

Magnetic and dielectric properties of the single crystals Sm 1xHo 

xFe 3(BO 3) 4 and Sm 1-xLa xFe 3(BO 3) 4 

Evgeniy Eremin*, Irina Gudim, Vladislav Temerov and Alexander Eremin 

Kirensky Institute of Physics SB RAS, Russia 

The trigonal rare-earth ferroborates with hantit ctructures is interested due to very 

strong of the electric polarization induced by magnetic field. The research of single 

crystals with double rare-earth subsystems such as Sm 1-xR xFe 3(BO 3) 4 (R = Ho, La) is 

important for analysis microscopic mechanism of magnetoelectric interaction. The 

single crystals of Sm 1-xHo xFe 3(BO 3) 4 with x = 0; 0.3; 0.5 and Sm 1-xLa xFe 3(BO 3) 4. with 

х = 0.25; 0.5 were grown by a flux method. The magnetic and magnetodielectric 

properties have been investigated. It has been revealed what magnetic behaviour and 

magnetodielectric effect essential depended on x. The magnetic field influence on the 

change in degree of dielectric penetrability is decreased with increasing x for both 

under study families. The decreasing of magnetodielectric effect is probably related 

with influence of the racemic twinning. 

RA24 

Far infrared spectroscopy of EuFe 3(BO 3) 4 

Kirill N. Boldyrev 1 *, Taras N. Stanislavchuk 2 , Marina N. Popova 1 and Sergey A. 

Klimin 1 

1 Solid State Spectroscopy, Institute of spectroscopy RAS, Russia 

2 Physics, New Jersey Institute of Technology, USA 

We present the results on the polarized far infrared absorption spectra of EuFe 3(BO 3) 4 

crystal in a wide range of temperature (3.5 - 300K). Rare-earth iron borates RFe 3(BO 3) 4 

undergo the antiferromagnetic phase transition at temperatures below 40 K, and some 

of them exhibit a significant magnetoelectric and magnetoelastic effect. EuFe 3(BO 3) 4 

is known to exhibit two phase transitions, the structural one at T C = 58 K [1], and the 

antiferromagnetic ordering at T N = 34 K [2]. The phonon frequencies demonstrate 

pronounced changes at T C, consistent with the observed peculiarities in the dielectric 

constant and thermal expansion [3]. Smaller but clearly visible phonon shift were 

registered below T N, thus evidencing the spin-lattice interaction in the title compound. 

[1] M.N. Popova, Journal of Rare Earths, 27, 607 (2009). [2] M.N. Popova, Journal of Magnetism 

and Magnetic Materials, 321, 716 (2009). [3] A.M. Kadomtseva, Yu.F. Popov, G.P. Vorob’ev, A.P. 

Pyatakov, S.S. Krotov, K.I. Kamilov, J. Low Temp. Phys., 36(6), 640 (2010). 

RA25 

RA26 

RA27 


Electric polarization, toroidal moments, spin chirality, spin canting at 

avoided level crossing induced by Dzyaloshinsky-Moriya interaction in 

V 3 nanomultiferroics in transverse magnetic field 

Moisey Belinsky 

School of Chemistry, Tel-Aviv University, Tel Aviv, Israel 

The spin-frustrated V 3 and Cu 3 nanomagnets with the Dzialoshinsky-Moriya (DM) interaction have 

received great attention for potential application in quantum computation [1-8]. V 3 with the out-of-plane 

Dz and in-plane Dn DM interactions demonstrates the multiferroic behavior in longitudinal magnetic field 

Bz||Z: field-induced polarization Pz(Bz) and toroidal moments Tz(Bz), which depend on the vector Κz(Bz) 

[scalar χ(Bz)] chirality, and complicated individual spin dynamics at avoided level crossing (ALC) [7]. 

In order to investigate the multiferroic behavior in transverse field Bx┴Z and B-reversal/rotation effects, 

P(Bx), Tn(Bx), M(Bx)magnetization, Κz(Bx), χ(Bx) and spin canting were calculated for B┴Z. The spin 

current P~Is mechanism [9] is the driving force of Pz(Bx) with a maximum at ALC that corresponds to 

Is(max). The in-plane DM leads to the in-plane Tn(Bx) which exhibits T-flop under B-rotation/reversal. 

Tn(B), χ(B), orbital moment M'(B), circular orbital current Io~χ [Pz(B), Κz(B), Is] show the switch on/off 

[reduction] under B-rotation within vertical XZ plane. Field behavior Pz(Bx), Tn(Bx) , M(Bx), Κz(Bx), 

Is, Io, and individual spin dynamics for Bx┴Z strongly differ from that for Bz||Z. V 3 exhibits non-linear 

reduction of Κz(Bx)vector chirality, χ(Bx)=0, and the entanglement effect. The V 3 nanomultiferroics 

demonstrate magnetically controlled anisotropic Pz(B), Tn(B), M(B), Κz(B), χ(B), M', Is, Io characteristics. 

1. T. Yamase et al., Inorg. Chem. 43, 8150 (2004). 2. Y. Kohama et al., J. Solid. State. Chem. 182, 1468 (2009). 3. K.-Y. Choi et 

al., Phys.Rev.Lett. 96, 107202 (2006); Phys. Rev. B 77, 024406 (2008). 4. M. Trif et al., Phys.Rev Lett. 101, 217201 (2008). 5. M. 

Trif et al., Phys.Rev. B 82, 045429 (2010). 6. M. F. Islam et al., Phys. Rev. B 82, 155446 (2010). 7. M.I. Belinsky, Phys. Rev. B 

84, 064425 (2011). 8. M.I. Belinsky, Chem. Phys. 361, 137, 152 (2009). 9. H. Katsura et al ., Phys. Rev. Lett. 95, 057205 (2005). 

Mössbauer studies of bismuth ferrite 

Seungkyu Han, Yong Hui Li, Minseon Kim, Sam Jin Kim and Chul Sung Kim* 

Physics, Kookmin University, Korea 

Perovskite bismuth ferrite (BiFeO 3) is a multiferroic material, having ferroelectric order 

(T C = 1,103 K) and antiferromagnetic order (T N = 643 K) [1]. It is a possible candidate for 

information storage, spintronics, and sensors applications [2]. Here, we have measured the 

magnetic properties of BiFeO 3 using x-ray diffractometer, field emission scanning electron 

microscope (FE-SEM), vibrating sample magnetometer, and Mössbauer spectroscopy. 

Single phased BiFeO 3 was synthesized by a low-temperature hydrothermal method. FE- 

SEM results showed that the grain sizes of microsphere and microcube were about 80 μm 

and 50 μm, respectively. BiFeO 3 powder showed weak-ferromagnetic behavior with a small 

magnetization value (Ms ~ 100 memu/g) at 295K. Rietveld refinement analysis showed that 

Fe-site and O-site splits into two pairs, respectively. The Mossbauer spectra of BiFeO 3 were 

analyzed with 2-set sextet. Isomer shift (δ) values showed that Fe 3+ ions existed in octahedral 

site. Electric quadrupole shift (EQ) values suggested different lattice distribution at octahedral 

site. Based on EQ values (0.02 ~ 0.1 mm/s), splitting into two partially occupied sites results 

in a distorted FeO 6 octahedral. The weak ferromagnetism observed in the hydrothermallyprepared 

BiFeO 3 particles comes from distorted FeO 6 octahedral, leading to incomplete 

counterbalance between the antiferromagnetic sublattices of the Fe ions. 

[1] G. A. Smolenskii and I. chupis, Sov. Phys. Usp. 25, 475 (1982). [2] J. Wang, J. B. Neaton, 

H. Zheng, V. Nagarajan, S. B. Ogale, B. Liu, D. Viehland, V. Vaithyanathan, D. G. Schlom, U. V. 

Waghmare, N. A. Spaldin, K. M. Rabe, M. Wuttig, and R. Ramesh, Science 299, 1719 (2003). 

Synthesis and electrical characterization of Bi 1-xY xFeO 3 ceramics 

Vikash Singh*, Manoj Kumar and R. K. Dwivedi 

Physics & materials science & engg., Jaypee institute of information technology, 

India 

Compositions within range 0.05 ≤ x ≤ 0.20 in the system Bi 1-xY xFeO 3 (BYFO) have 

been synthesized by solid state reaction method. Structural and electrical properties of 

yttrium doped bismuth ferrite ceramics have been investigated. Single-phase formation 

has been confirmed by x-ray diffraction, which has shown rhombohedral symmetry 

with R3c space group at room temperature. Temperature dependent dielectric behavior 

of BYFO ceramics with in composition range 0.05 ≤ x ≤ 0.20 at few frequencies 

have shown an anomaly near the temperature which corresponds to magnetic phase 

transition ‘T N’ for pure BiFeO 3 material (i.e.370 o C). Substitution of yttrium in BFO has 

shown a shift in T N. The temperature dependence of ac conductivity indicates that the 

conduction process may be influence by defects which occurs due to oxygen vacancies. 

1. N. A. Hill, Why are there so few magnetic ferroelectrics, J. Phys. Chem. B 104, 669 (2000). 2. 

H. Singh, K.L. Yadav, Dielectric, magnetic and magnetoelectric properties of La and Nb codoped 

bismuth ferrite, J. Phys.: Condens. Matter 23, 385901 (2011). 


Poster Thursday



RA28 

Lattice engineering on transition metal oxide thin film 

Chang Uk Jung* 


Transition metal oxide having a perovskite structure showed a large spectrum of 

physical properties. YBa2Cu3O7 showed high temperature superconductivity, 

(La,Ca,Sr)MnO3 showed ferromagnetism with half metallicity, Pb(Zr,Ti)O3 showed 

Ferroelectricity, and BiFeO3 showed coexistence of antiferromagnetism and 

ferroelectricity. Recent advance in interface control revealed a 2d electron gas, interface 

superconductivity, interface magnetism, oribital reordering, interface thermoelectric 

effect at the interface of transition metal oxide. The effect of lattice distortion has been 

studied for a long time and recently showed that lattice distortion during thin film 

growth can create new ground state. Especially ATiO3, (A=Sr, Y, Eu) was interesting. [In 

bulk state, YTiO3 and EuTiO3 are magnetic insulator, and SrTiO3 is not ferroelectric.] 

I will introduce the some current research on the progress on these materials In this 

case, only lattice mismatch between substrate and film was used. On the contrary 

the available substrate is rather narrow. I will also introduce efforts to overcome this 

problem. 

[1] A. Ohtomo & H. Y. Hwang, Nature 427, 423 (2004), [2] N. Reyren et al., Science 317, 1196 

(2007). [3] J. Chakhalian et al., Science 318, 1115 (2007). [4] S. C. Chae,et al., Appl. Phys. Lett. 89, 

182512 (2006). [5] J. H. Haeni et al., om, Nature 430, 758 (2004). [6] June Hyuk Lee et al., Nature 

466, 954 (2010). [7] C. U. Jung et al.,, Appl. Phys. Lett., 84, 2590 (2004). [8] B. W. Lee et al., J. of 

Appl. Phys., 104, 103909 (2008). [9] B. W. Lee et al.,, APL 96, 102507 (2010). 

RB01 

Structural and magnetic properties of doped iron oxo-selenides 

Sven Landsgesell 1 , Karel Prokes 1 and Dimitri Argyriou 2 

1 M-I1, Helmholtz-Zentrum Berlin, Germany 

2 European Spallation Source, Sweden 

In the Cu oxide superconductors the Cu resides in a square planar geometry[1], while in the 

Fe pnictide superconductors the Fe ion resides in a tetrahedrally coordinated position[2]. 

Both compounds may show a separating LaO layer between the superconducting sheets. 

La 2O 3Fe 2Se 2 shows square planar Fe O sheets and offers a direct super exchange pathway 

to the next nearest Fe neighbour via the Se, comparable to the iron arsenides[3]. These super 

exchange pathways are similar to the superconductors despite the difference and provide 

a similar local environment for the Fe as is known for the Fe-superconductors[4]. We 

investigated the changes in the physical properties in the iron oxo-selenides by varying the 

electron density and structural components. We doped the parent compound with F, Cd and 

rare earths with smaller radii (La 2O 3-xFxFe 2Se 2, and La 2-x(Cd/RE) xO 3Fe 2Se 2, respectively). 

Temperature dependent neutron diffraction of the samples mostly show an antiferromagnetic 

order along the a-direction with a propagation of (0.5 0 0.5). We find indications for an 

evolving transition in the physical properties, as decreasing TN for fluorine and rare earth 

samples. This is comparable to the known doped iron superconductors and in contrast to the 

electron deficient Cd doped samples that show an in creasing TN. 

1 D. Vaknin et al., Phys. Rev. Lett. 58, 2802 (1987) 2 Y. Kamihara et al., J. Am. Chem. Soc. 130, 

3296 (2008) 3 E. Manousakis et al., Solid State Comm. 150, 62 (2010) 4 D.G. Free and J.S.O. 

Evans, Phys. Rev. B 81, 214433 (2010) 

RB02 

Phase separation of antiferromagnetism and superconductivity in 

Rb xFe 2-ySe 2 observed by Rb NMR 

Yoshiaki Kobayashi 1 *, Shunsuke Saiki 1 , Shouhei Kototani 1 , Masayuki Itoh 1 and 

Masatoshi Sato 2 


2 Research Center For Neutron Science And Technology, CROSS, Japan 

The observation of the superconducting (SC) transition in A xFe 2-ySe 2 (A: alkali metal 

elements; Tc of ~30K) has been one of surprising things, because the transition was 

found in the antiferromagnetic (AF) system with a large AF moment of ~3.3 μB/ 

Fe. Moreover, their electrical resistivity just above Tc is too large to conceive the 

occurrence of the superconductivity. Here, to clarify whether the AF and SC states 

are microscopically coexistent or just phase-separated, we have carried out NMR 

measurements on both crystals with and without SC transition. The Rb-NMR spectra 

below 300 K observed for these crystals are clearly separable into two parts with 

different widths. The broader spectrum can be explained by the presence of the 

region with the “blocked” antiferromagnetic spins proposed by the neutron magnetic 

scattering studies [1]. The narrower spectrum for the crystal with SC transition can 

be understood from its temperature dependence and spectral shape to stem from 

the superconducting region without Fe-vacancy ordering [1]. Thus, we can clearly 

conclude that the superconductivity and the antiferromagnetism in the present system 

are phase-separated. 

[1] W. Bao, et al., Chin. Phys. Lett. 28, No. 8 (2011) 086104. 


RB03 

Superconductivity of EuFe 2As 2 under high pressure 

Shugo Ikeda and Hisao Kobayashi 

Graduate School of Material Science, University of Hyogo, Japan 

EuFe 2As 2 with the tetragonal ThCr 2Si 2-type structure exhibits a spin density wave 

(SDW) transition at 190 K, with a simultaneous structural change [1]. The SDW 

transition is suppressed by applied pressure and bulk superconductivity appears around 

2.5 GPa [1-3]. Furthermore, magnetic moments of Eu sublattice order magnetically 

at To = 19 K. The value of To reveals no changes at pressures of up to 3 GPa [1-3]. 

We have studied the superconductivity and the magnetism of EuFe 2As 2 by measuring 

dc magnetization and 57Fe nuclear forward scattering (NFS) under high pressure. 

Magnetization at 2.6 GPa rapidly increases below 24 K and then gradually decreases 

by the appearance of superconductivity. The size of the drop at low temperatures is 

consistent with nearly 100 % shielding. Namely, bulk superconductivity appears under 

the magnetic ordered state of Eu sublattice. The pressure dependence of 57Fe NFS 

spectra shows the decrease of the hyperfine field Bhf of Fe sublattice with increasing 

pressure. Furthermore, it is found that the direction of Bhf varies around 2.6 GPa, 

implying the changes of magnetic structure. In this presentation, we will discuss the 

relation between the superconductivity and the magnetism of EuFe 2As 2, considering 

these results. 

[1] K. Matsubayashi et. al : Phys. Rev. B 84 (2011) 024502. [2] N. Kurita et. al : arXiv: 

1103.4209v1. [3] T. Terashima et. al : J. Phys. Soc. Jpn. 78 (2009) 083701. 

RB04 

Superconductivity in 4d, 5d pnictides 

Tomohiro Takayama 1 *, Daigorou Hirai 1 , Keisuke Kuwano 1 and Hidenori Takagi 2 

1 Department of Advanced Materials, University of Tokyo, Japan 

2 Department of Physics, University of Tokyo, Japan 

After the discovery of the iron arsenide superconductors, a tremendous effort has 

gone into the search for new high-Tc superconductors. We explored 4d, 5d pnictides, 

hoping to find superconductors which share important characteristics with Febased 

superconductors. We report two new superconducting systems with such 

characteristics, but sufficiently different from Fe pnictides. (i) APt 3P (A = Ca, Sr and 

La) The new compounds APt 3P crystallize in an antiperovskite structure with distorted 

PPt6 octahedra. All of them display superconductivity below 6.6, 8.4 and 1.5 K for 

Ca-, Sr- and LaPt 3P, respectively. The highest-Tc compound SrPt 3P exhibits strongcoupling 

s-wave superconductivity. The presence of multiple pocket Fermi surface 

was inferred in SrPt 3P, which might enhance the coupling with low-energy phonons. 

(ii) RuPn (Pn = P, As) Binary RuPn crystallize in an orthorhombic MnP-type structure. 

RuP and RuAs were found to show a metal to non-magnetic insulator transition at 270 

and 200 K, respectively. The structural analysis evidenced another phase transition at 

higher temperatures, indicative of pseudogap formation. The two transitions can be 

suppressed by Rh-doping. We discovered superconductivity with a maximum Tc = 3.7 

K and 1.8 K at the critical doping level for suppressing the pseudogap-phase in Ru1xRhxP 

and Ru1-xRhxAs, respectively. 

D. Hirai et al., arXiv:1112.0604 

RB05 

Elastic softening and electric quadrupole in iron pnictide 

superconductor Ba(Fe 1-xCo x) 2As 2 

Ryosuke Kurihara 1 , Koji Araki 1 , Keisuke Mitsumoto 1 , Mitsuhiro Akatsu 1 , Yuichi 

Nemoto 2 , Terutaka Goto 2 , Yoshiaki Kobayashi 3 and Masatoshi Sato 4 

1 Graduate School of Science and Technology, Niigata University, Japan 

2 Graduate School of Science and Technology, Niigata University, JST-TRIP, Japan 

3 Department of Physics, Nagoya University, JST-TRIP, Japan 

4 Department of Physics, Nagoya University, CROSS, JST-TRIP, Japan 

We have performed ultrasonic measurements on iron based superconductor Ba(Fe 1-xCo x) 2As 2 in order 

to investigate the mechanism of the superconductivity. The end-material BaFe 2As 2 shows structural and 

antiferromagnetic simultaneous transitions at~140K. With increasing Co concentration x, the temperatures of 

these transition are lowered and separated from each other. The superconductivity appears at x>0.03. In our 

recent work [1], the softening of the elastic constant C66 as large as 21% was observed for optimized samples 

Ba(Fe 0.9Co 0.1) 2As 2 with decreasing temperature from 300K down to superconducting transition temperature 

of TSC=23 K, while other elastic constants do not show softening. Here, we have measured elastic constants 

of Ba(Fe 1-xCo x) 2As 2 samples with x=0,0.03 and 0.07, where only the C66 shows huge softening larger than 

70% with decreasing temperature down to the structural transition temperature. The large softening of C66 

in Ba(Fe 1-xCo x) 2As 2 with several Co concentration x≤0.10 has been reported by other groups [2,3]. This huge 

elastic softening of C66 is caused by the quadrupole fluctuation associated with the degenerate dy’z and dzx’ 

band aslant Γ and X points of the Brillouin zone. Quadrupole effects on the superconductivity in the present 

system are discussed in relation to the s++ type symmetry of the superconductivity [4,5,6]. 

[1] T. Goto, et al., JPSJ 80 (2011) 073702. [2] R. M. Fernandes et al., PRL 105 (2010) 157003. [3] 

M. Yoshizawa et al., JPSJ 81 (2012) 024604. [4] Y. Yanagi et al., JPSJ 79 (2010) 123707. [5] H. 

Kontani et al., PRB 84 (2011) 024528. [6] T. Kawamata et al JPSJ 80 (2011) 084720.

RB06 

Concentration dependence of magnetic and transport characteristics 

in EuFe 2As 2-xP x single crystals 

Takanari Kashiwagi*, Takuya Ishikawa, Tomoki Goya, Youhei Jono, Akihiko 

Nozawa, Kasumi Tashima and Kazuo Kadowaki 

Univ. of Tsukuba, WPI-MANA, JST-CREST, Japan 

EuFe 2As 2 exhibits the spin-density wave of Fe spins at TSDW=190 K and 

subsequently magnetic order of Eu 2+ moment at TN=19 K. It is also known that this 

compound shows the superconductivity by isovalent substitution of As to P and the 

Tc value increases up to 28 K. We have studied magnetic and transport properties in 

single crystal of the EuFe 2As 2-xP x system grown by the self-flux method. From the 

magnetization measurements at 5 K, we observed a saturation of magnetization of Eu 2+ 

at HM ~ 1 T and a spin-flop like behavior at Hsf ~ 0.6 T for H||ab-plane. These fields 

seem to decrease as x is increased, indicating reduction of the exchange interaction and 

the uniaxial anisotropy. We also performed electron spin resonance measurements at 

X-band on single crystals of EuFe 2As 2-xP x. The result shows that the resonance field 

increases with decreasing temperature toward to TN=19 K below which a new line was 

observed. We will discuss these results including electron spin resonance experiments 

with emphasis on the phase diagram of magnetism and superconductivity in EuFe 2As 2xP 

x. 

RB07 

Resonance-like response in antiferromagnetically ordered 

Fe 1.02Te 0.95Se 0.05, studied by polarized inelastic neutron scattering 

Karel Prokes 1 *, Arno Hiess 2 , Wei Bao 3 , Sven Landsgesell 1 , Elisa Wheeler 4 and Dimitri Argyriou 2 

1 M-I1, Helmholtz Zentrum Berlin, Germany 

2 European Spallation Source ESS AB, 22100 Lund, Sweden 

3 Renmin University of China, 100872 Beijing, China, China 

4 M-I1, Institut Laue-Langevin, 38042 Grenoble Cedex, France 

Unconventional superconductivity in iron pnictides and chalcogenides [1] shows intriguing similarities with 

both copper-oxide- and rare-earth-based superconductors. Common is a proximity to a magnetic order and an 

existence of magnetic fluctuations [2]. Magnetic fluctuations change below the superconducting transition and 

are readily detectable by neutron inelastic scattering. The character of these has been shown to be related to the 

pairing mechanism and gap symmetry [3]. In all superconducting pnictides and chalcogenides one finds welldefined 

magnetic excitations centered close to the Q = (0.5, 0.5, 0) reciprocal position that strongly disperse 

with increasing energy and peaking in the 6.5-9.8 meV range [2]. Polarization neutron experiment allows for a 

determination of the in-plane and out-of-plane inelastic responses that are proportional to the relevant imaginary 

parts of the dynamical susceptibility. While the fluctuations in FeTe 1-xSe x, x = 0.40 are nearly isotropic with a 

slightly enhanced component along the c axis [4,5], in BaFe 1.9Ni 0.1As 2 they are have an in-plane 2D character 

[6]. In this contribution we report on a polarized neutron study showing that similar fluctuations also exist also in 

antiferromagnetically ordered Fe 1.02Te 0.95Se 0.05 above the magnetic phase transition. 

[1] F.-C. Hsu, et al., Proc. Nat Acad. Sci. USA 105, 14262 (2008). [2] D. C. Johnston, Advances in Physics 59, 803 

(2010). [3] M. M. Korshunov and I. Eremin, Phys. Rev. B 78, 140509 (R) (2008). [4] P. Babkevich, et al., Phys. Rev. B 

83, 180506 (R) (2011). [5] K. Prokes et al., to be published [6] O. J. Lipscombe, et al., Phys. Rev. B 82, 064515(2010). 

RB08 

Influence of filament diameter on superconducting properties of MgB 2 

multi-core wires 

Michael Reissner 1 *, Lukas Bulla 1 , I Husek 2 , T Melisek 2 and P Kovac 2 

1 Institute of Solid State Physics, Vienna Universtity of Technology, Austria 

2 Institute of Electrical Engineering, Slovak Academy of Sciences, Slovak 

Multi-core MgB 2 wires with 19 filaments of different diameter were produced [1]. The 

filaments are covered by a Ti shell and embedded in a Cu matrix. From outside the 

wires are stabilized by stainless steel tubes. Critical current densities were determined 

from hysteresis loops using Bean's model [2]. Magnetic relxation measurements were 

performed at 1, 3, and 5 T both in increasing and decreasing field for up to 30 min. 

From these measurements mean effective activation energies were determined within 

the flux creep theory of Anderson [3]. All samples were prepared in identical way. They 

only differ in diameter of the filaments, which ranges between 30 and 15 μm. Influence 

of the filament diameter on the superconducting properties, like critical current density, 

irreversibility line and activation energies are discussed. 

[1] P Kovac, I Husek, T Melisek, L Kopera, M Reissner Supercond. Sci. Technol 23 (2010) 065010 [2] 

C P Bean Phys. Rev. Lett. 9 (1962) 250 [3] P W Anderson Phys. Rev. Lett. 9 (1962) 309 

RB09 

RB10 

RB11 


Kinetic energy density of cooper pairs in Sr doped YBa 2Cu 3O 7-δ single 

crystals 

Ana Paula Aguiar De Mendonca 1 *, Rovan Fernandes Lopes 1 , Valdemar Das Neves 

Vieira1, Fabio Teixeira Dias 1 , Douglas Langie Da Silva 1 , Paulo Pureur 2 , Jacob Schaf 3 , 

Mauro Melchiades Doria 4 and Frederik Wolff-fabris 5 

1 Universidade Federal de Pelotas, Brazil 

2 Universidade Federal do Rio Grande do Sul, Brazil 

3 Universidade Federal do Rio Grande so Sul, Brazil 

4 Universidade Federal do Rio de Janeiro, Brazil 

5 HZ Dresden-Rossendorf, Germany 

The kinetic energy, K(T) is a relevant tool to sort the distinct proposal for the normal state and their 

consequent paring mechanisms in HTSC.[1,2] Motivated by this potential we report on reversible DC 

magnetizations as a function of temperature of a series of YBa 2-xSr xCu 3O 7-δ (x = 0, 0.02, 0.10, 0.25, 0.37 

and 0.50) single crystals with the purpose to study the role of ion size chemical introduced disorder on the 

average kinetic energy density (AKED) of Cooper pairs in the YBa 2Cu 3O 7-δ superconducting state.[3] The 

Sr ion size chemical disorder is introduced in YBa 2Cu 3O7-? structure by lattice distortion. The valuation 

of the AKED from reversible dc magnetization data is supported by viral theorem of superconductivity. 

[1,2,4] The AKED preliminary results of the YBa 1.9Sr 0.1Cu 3O 7-δ single crystal show that the series of the 

isofield K(T) curves, obtained to the H = 10 kOe, scales in a common behavior that smoothly develops as 

the temperature is increasing toward to the Tc, disappearing inside a common background for T > Tc. This 

interested AKED behavior strongly suggests an existence of a unique superconducting condensate state. At 

this time the dc magnetization measurements in additional samples are in progress. 

1. S. Salem-Sugui, Jr., M. M. Doria, A. D. Alvaraga, V. N. Vieira, P. F. Farinas and J. P. Sinnecker, Phys. Rev. B 76, 132502 

(2007). 2. M. M. Doria, S. Salem-Sugui, I. G. de Oliveira, L. Ghivelder and E. H. Brandt, Phys. Rev. B 65, 144509 (2002). 3. V. N. 

Vieira and J. Schaf , Phys. Rev. B 65, 144531 (2002). 4. M. M. Doria, J. E. Gubernatis and D. Rainer Phys. Rev. B 39, 9573 (1989). 

Interplay between superconductivity and antiferromagnetism in BaFe 2xNi 

xAs 2 single crystals studied by 57Fe Mossbauer spectroscopy 

Julian Andres Munevar Cagigas 1 , Hans Micklitz 2 , Chenglin Zhang 3 , Hui Quian Luo 4 , 

Pengcheng Dai 5 and Elisa Baggio-saitovitch 1 * 

1 Brazilian Center for Research in Physics, Brazil 


3 Department of Physics, University of Tennessee, USA 

4 Beijing National Laboratory for Condensed Matter Physics, China 

5 Department of Physics and Astronomy, University of Tennessee, USA 

We have performed magnetic susceptibility and 57Fe Mossbauer spectroscopy measurements on single 

crystal mosaics of BaFe 2-xNi xAs 2 (x=0.065, 0.075, 0.085). Our findings show antiferromagnetic order below 

TN obtained from magnetic hyperfine field phase diagram, with superconductivity below TC obtained by 

susceptibility measurements. Careful analysis of our Mossbauer data show that a decrease in the magnetic 

hyperfine field is observed below TC and the effect is proportional to the difference between TN and TC, being 

the largest when both temperatures become close. We argue this is caused by coexistence of superconductivity 

and magnetism, since both phenomena come from the same Fe 3d electrons, and two possible scenarios are 

presented. Magnetic volume fraction does not show any variation at or below TC, but a strong dependence 

with doping level, most likely due to short range magnetic order that cannot be sensed by our 57Fe local probe, 

probably caused by local inhomogeneities. A phase diagram is shown to illustrate how the variation of the 

magnetic volume fraction and the crossover between magnetism and superconductivity are related. 

M. Wang, H. Luo, J. Zhao, C. Zhang, M. Wang, K. Marty, S. Chi, J. W. Lynn, A. Schneidewind, S. Li and P. Dai, 

Physical Review B 81, (2010) 174524. M. Alzamora, J. Munevar, E. Baggio-Saitovitch, S. L. Bud'ko, Ni Ni, P. C. 

Canfield and D. R. Sanchez, Journal of Physics: Condensed Matter 23, (2011) 145701. arXiv:1111.5853 

Magnetism in superconducting Ba0.78K. 22Fe2As2 and EuFe2As1.4P0.6 single crystals studied by Mossbauer spectroscopy 

Elisa Baggio-saitovitch 1 , Julian Munevar 1 , Hans Micklitz 1 , Genfu Chen 2 , Chenglin 

Zhang 3 , Huiqian Luo 4 and Pengcheng Dai 5 

1 

Brazilian Center for Research in Physics, Brazil 

2 

Renmin University of China, China 

3 

Department of Physics and Astronomy, University of Tennessee, USA 

4 

Beijing National Laboratory for Condensed Matter Physics,, China 

5 

Department of Physics and Astronomy, University of Tennessee Neutron Scattering Division, ORNL, USA 

We studied magnetism in superconducting Fe-pnictide single crystals using 151Eu and 57Fe Mossbauer 

Spectroscopy. Neutron studies on Ba 1-xK xFe 2As 2 single crystals revealed a decrease in Bragg peak intensity due 

to iron moment or magnetic volume fraction reduction. 57Fe Mossbauer measurements on Ba 0.78K 0.22Fe 2As 2 

single crystal mosaics were performed down to 1.5 K, revealing a decrease in the magnetic hyperfine field 

below Tc, without change in magnetic volume fraction. Our data confirm a reduction of Fe magnetic moment 

below Tc explaining also the neutron results. Such a decrease is caused by a spectral weight transfer when 

entering the superconducting state. For EuFe 2As 1.4P 0.6 compound, magnetism originates from Eu 2+ moments. 

Mossbauer spectra reveal magnetic hyperfine fields below TM = 18 K of Eu 2+ moments. Data analysis 

shows coexistence of ferromagnetism, from Eu 2+ moments ordered along crystallographic c-axis, and 

superconductivity below TSC ~ 15 K. We find indications for a change of small Fe magnetic moment dynamics 

(~ 0.07 μB) at superconductivity onset: below TSC the Fe magnetic moments seem to be “frozen” within the 

a,b-plane. In both compounds we show a change in the Fe magnetic moment state when entering the SC state, 

and discussion about coexistence of magnetism and superconductivity will be provided. 

[1] Z. Ren et al., Chin. Phys. Lett. 25, 2215 (2008) [2] M. Lumsden et al., J. Phys: Cond. Mat. 22 

(2010) 203203. [3] H.H. Luetkens et al., Nat. Mater. 8 (2009) 305. 


Poster Thursday


RB12 


Doping evolution of the in-plane London penetration depth in 

Fe1+y(Te1-xSex) single-crystals 

Andrei Diaconu 1 , Jin Hu 2 , Tijiang Liu 2 , Bin Qian 2 , Zhiqiang Mao 2 and Leonard Spinu 1 

1 

Advanced Materials Research Institute and Physics Department, University of New 

Orleans, USA 

2 

Department of Physics, Tulane University, USA 

Our work focuses on the doping evolution of the superconducting properties as derived 

from penetration depth measurements as a function of temperature in single crystals 

of Fe 1+y(Te 1-xSe x) with y

RB18 

Monte Carlo study of the magneto-elastic effects in Fe pnictides 

Cesar Jose Calderon Filho 1 *, Alex Antonelli 1 , David Vaknin 2 and Gaston Eduardo 

Barberis 1 

1 IFGW, State University of Campinas - UNICAMP, Brazil 

2 Ames National Laboratory and Department of Physics, Iowa State University, USA 

A (J1, J2) model of the infinite square lattice of classical spins coupled by Heisenberg 

exchange interactions that includes a spin-lattice interaction of the form A (Exx - Eyy) 

(Sx2- Sy2) is used in Monte-Carlo simulations to determine a phase diagram in the 

J1, J2, and A parameter-space. To facilitate phase transitions in the 2D system, we 

also include a weak out-of-plane coupling to spins in adjacent planes (Jz). This phase 

diagram is relevant to the parent materials of the newly discovered iron-pnictides 

superconductors. Using first principles band calculations, both for the low and high 

temperatures, we obtain realistic parameters to the model that allow the prediction of 

pressure induced magnetic transitions. 

RB19 

Geometrical Vortex Transition in the iron pnictide SmFeAs(O,F) 

Philip J.w. Moll 1 *, Luis Balicas 2 , Janusz Karpinski 3 , Nikolai Zhigadlo 4 and Batlogg 

Bertram 5 

1 Solid State Physics Laboratory, ETH Zurich, Switzerland 

2 National High Magnetic Field Laboratory, Florida State University, USA 

3 Solid State Physics, ETH Zurich, Switzerland 

4 Solid State Laboratory, ETH Zurich, Switzerland 

5 Solid State Theory, ETH Zurich, Switzerland 

We have observed a distinct vortex matter transition in SmFeAs(O,F) (Tc~50K) upon 

cooling below T*~41K(=0.81Tc) into a highly mobile state for fields well aligned with the 

FeAs layers. Below T*, the vortex core is confined between two adjacent FeAs planes by 

periodic modulations of the superconducting order parameter within the unit cell. Vortex 

motion parallel to the planes is even more pronounced at lowest temperatures, well below 

Tc and Hc2, as the vortex cores avoid the highly effective pinning sites located in the FeAs 

layers. For fields slightly out-of-plane (10 6 A/cm 2 

@5K, 14T[1]). These results indicate strong pinning localized in the FeAs layer to be the 

dominant factor for the highly effective pinning and thus show the pathway to improve the 

technological prospect of the pnictides. 

[1] P.J.W. Moll et al., 'High magnetic field scales and critical currents in SmFeAs(O,F) crystals. 

Nature Materials 9, 628 (2010) 

RB20 

SmFeAsO 1-xF x: Raman scattering and x-ray diffraction study under 

low temperature and high pressure conditions 

Sofia Michaela Souliou 1 *, Mathieu Le Tacon 1 , Andrew C. Walters 1 , Chengtian Lin 1 , 

Karl Syassen 1 , Bernhard Keimer 1 , Gaston Garbarino 2 , Michael Hanfland 2 , Wilson 

Crichton 2 , Janusz Karpinski 3 and Nicolai Zhigaldo 3 

1 Max-Planck-Institut fur Festkorperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany, Germany 

2 European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France, France 

3 Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland, Switzerland 

We present a comparative low-temperature Raman study on single crystals of the parent non-superconducting 

SmFeAsO and the fluorine-doped superconducting SmFeAsO 0.6F 0.35 [1]. As in the compounds from the 122 

family [2], clear renormalization of the c-axis polarized A1g(Sm) and the B1g(Fe) Raman-active modes 

are observed through the magneto-structural transition in the parent compound. Splitting of the in-plane 

Eg modes is also observed (like the reported in [3,4]). In the fluorine-doped compound, x-ray diffraction 

measurements reveal the retention of the structural transition (similar to the one reported in [5]). Despite the 

absence of a coupled magnetic transition, a renormalization of the c-axis polarized modes similar to the one 

seen in the parent compound is observed, followed at lower temperature by an anomalous increase of the 

linewidth of these phonons below the superconducting transition temperature. The effects of the structural 

transition on the phonon modes are further investigating by applying high pressure on the parent compound, 

allowing a direct comparison of the effect of pressure and doping on the lattice dynamics of the system. 

[1] Z.-A. Ren et al., Chinese Physics Letters 25 (6), 2215 (2008) [2] M. Rahlenbeck et al., Phys. 

Rev. B 80, 064509 (2009) [3] T. Yildirim, Phys. Rev. Let. 101, 057010 (2008) [4] L. Chauviere et al., 

Phys. Rev. B 80, 094504 (2009) [5] A. Martinelli et al., Phys. Rev. Let. 106, 277001 (2011) 

RB21 

RB22 

RB23 


Mass renormalization in isostructural Ru- and Fe-pnictides 

Philip J.w. Moll 1 *, Jakob Kanter 1 , Ross Mc.donald 2 , Fedor Balakirev 2 , Peter Blaha 3 , 

Karlheinz Schwarz 3 , Zbigniew Bukowski 1 , Nikolai D. Zhigadlo 1 , Sergiy Katrych 1 , 

Kurt Mattenberger 1 , Janusz Karpinski 1 and Bertram Batlogg 1 

1 Solid State Physics Laboratory, ETH Zurich, Switzerland 

2 National High Magnetic Field Laboratory, Los Alamos National Laboratory, USA 

3 Institute of Materials Chemistry, Vienna University of Technology, Austria 

We have studied the angular-dependent de Haas-van Alphen oscillations of LaRu 2P 2 using 

magnetic torque in pulsed magnetic fields up to 60 T. The observed oscillation frequencies are 

in excellent agreement with the geometry of the calculated Fermi surface. The temperature 

dependence of the oscillation amplitudes reveals effective masses m*(α) = 0.71 and m*(β) = 

0.99 me, which are enhanced over the calculated band mass by λcyc of 0.8. We find a similar 

enhancement of λγ ~ 1 in comparing the measured electronic specific heat (γ =11.5mJ/mol 

K 2 ) with the total density of states from band-structure calculations. Remarkably, very similar 

mass enhancements have been reported in other pnictides, LaFe 2P 2, LaFePO (Tc ~ 4 K), and 

LaRuPO, independent of whether they are superconducting or not. This is contrary to the 

common perceptions that the normal-state quasiparticle renormalizations reflect the strength 

of the superconducting pairing mechanism. To separate mass enhancement due to electron 

correlations from e.g. electron-phonon interactions, high energy bandwidth measurements such 

as ARPES would be highly desirable, thus leading to new questions about competing pairing in 

isostructural and isoelectronic Ru- and Fe-pnictide superconductors. 

PHYSICAL REVIEW B 84, 224507 (2011) 

The role of spin fluctuation for the high Tc superconductivity in 

LiFeAs, LiFeP, NaFeAs 

Geunsik Lee, Hyo Seok Ji and Ji Hoon Shim* 


Based on fully self-consistent density functional theory and dynamical mean field 

theory (DMFT) methods, we have studied the electronic spectrum of three isovalent 

111 compounds, LiFeAs, LiFeP, NaFeAs. It has been known that while both LiFeAs 

and LiFeP are intrinsic superconductors with the nodeless and nodal gap symmetries 

respectively, NaFeAs exhibits spin density wave phase where superconducting 

transition occurs with chemical doping. With our simulated electronic spectrums, we 

examine the spin fluctuation mechanism for the high Tc superconductivity. 

DFT+DMFT study on the electronic structure and anisotropy of 

Sr 2VO 3FeAs superconductor. 

Hyo Seok Ji and Ji Hoon Shim* 


Electron correlation effect on Fe 3d orbital has very important role in describing 

electronic structure and anisotropy of iron-based superconductors.[1] By using 

combination of the density functional theory (DFT) and dynamical mean field theory 

(DMFT), the electron correlation effect can be described well. In this study, we have 

investigated the electronic structure and anisotropy of Sr 2VO 3FeAs superconductor. 

Simple DFT result shows mixed band structures of Fe 3d and V 3d orbital, but the 

experimental result shows only Fe 3d band near the Fermi level.[2] The DFT+U 

method explains insulating V layer structure correctly[2, 3] but it cannot describe 

whole electronic structure such as renormalized Fe 3d bands. So we apply the electron 

correlation effect on the V 3d orbital as well as the Fe 3d orbital using DFT+DMFT. 

With antiferromagnetic(AFM) ordering, V 3d bands split into -1 eV and 1 eV region, 

which is consistent with experimental ARPES result.[2] Also we calculate electrical 

anisotropy γ=σ_xx/σ_zz which is important for determining dimensionality effect in 

iron-based superconductors. Calculated anisotropy value is much smaller than simple 

DFT result and the result is well consistent with recent experimental result. This trend 

is also consistent with the trend of previous work[1]. 

[1] H. S. Ji, G. Lee, and J. H. Shim, Phys. Rev. B 84, 054542 (2011). [2] T. Qian et al., Phys. Rev. B 

83, 140513(R) (2011). [3] H. Nakamura and M. Machida, Phys. Rev. B 82, 094503 (2010). 


Poster Thursday


RB24 


Behaviour of Magnetic and structural transitions upon Sr doping in 

CaFe 2As 2 and EuFe 2As 2 

Neeraj Kumar*, Ruta Kulkarni, Sudesh Kumar Dhar and Arumugam Thamizhavel 

Condensed Matter Physics and Materials Science, Tata Institute of Fundamental 

Research, Mumbai, India, India 

We have grown single crystals of Ca 1-xSr xFe 2As 2 and Eu 1-xSr xFe 2As 2. Our aim was to 

study the progression of SDW transition and the effect of dilution on Eu magnetism 

in EuFe 2As 1-xSr xFe 2As 2. CaFe 2As 2 and SrFe 2As 2 undergo magneto-structural transition 

at 170 K and 205 K respectively[1,2]. With introduction of Sr in the CaFe 2As 2, 

magneto-structural transition temperature increases, and it reaches 200 K in nominal 

Sr 0.5Ca 0.5Fe 2As 2 indicating that Sr dominates Ca in determining the SDW and structural 

transition. Doping Fe with Co induces superconductivity in Ca 0.5Sr 0.5Fe 2As 2 below 12 K, 

which surprisingly shows a signature of SDW transition at a high temperature of 170 

K. In Eu 1-xSr xFe 2As 2 series the AFM ordering temperature of Eu sublattice decreases 

with increasing x while the structural/SDW transition temperature gradually varies 

from 190 K to 200 K. Field induced ferromagnetic behaviour of the parent EuFe 2As 2 

is also observed in the Sr doped compounds, the magnetic field needed to induce 

ferromagnetism decreases with increasing Sr. 

[1] Neeraj et. al. Phys. Rev. B, 79, 012504 (2009). [2] Krellner et al, Phys. Rev. B, 78, 100504(R) 

(2008) 

RB25 

Specific heat of the vortex lattice in iron-pnictide superconductors 

Miguel Araujo 1 and Pedro Sacramento 2 

1 

CFIF, Instituto Superior Tecnico, TU Lisbon and Department of Physics, Universitiy 

of Evora, Portugal 

2 

CFIF, Instituto Superior Tecnico, TU Lisbon, Portugal 

We study a vortex lattice in a three-orbital model for iron-pnictide superconductors. A 

gauge transformation, first introduced by Vafek-Tesanovic [1], is employed in order 

to obtain an effective spatially periodic Hamiltonian that produces a spectrum of 

Bloch states and automatically includes quantum effects, such as the Berry phase and 

Doppler shift of quasi-particles, without resorting to semi-classical approximations. We 

calculate the energy spectrum and specific heat as function of applied magnetic field. 

The effect of disorder due to impurities and positional disorder of the vortices is also 

addressed. 

[1] O. Vafek, A. Melikyan, M. Franz and Z. Tesanovic, Physical Review B 63, 134509 (2001) 

RB26 

Hexagonal superconducting pnictide SrPtAs: an ab initio study 

Sonny S. H. Rhim 1 , S. J. Youn 2 , Daniel Agterberg 3 , Michael Weinert 3 and Arthur J 

Freeman 1 

1 Physics and Astronomy, Northwestern University, USA 

2 Physics Education and Research Institute of Natural Science, Gyeong Sang National 


3 Physics, U. Wisconsin-Milwaukee, USA 

We present an ab initio study on SrPtAs, a recently discovered hexagonal pnictide 

superconductor. SrPtAs is distinct from other pnictides: (i) it has a hexagonal structure 

and (ii) a large spin-orbit interaction, whose consequence is not trivial. Based on 

electronic structure calculations, a tight-binding Hamiltionian is constructed to analyze 

the character of the spin-orbit interaction associated with the crystal structure. Further, 

the pairing mechanism by phonon and spin fluctuation are analyzed from phonon 

dispersion and susceptiblity with matrix element fully taken into account. Finally, 

based on the band structure, we propose that electron doping could increase TC. 


RB27 

Josephson effect in BaKFeAs inter-grain boundary junctions 

Sung-hak Hong 1 , Sung Hoon Lee 1 , Soon-gul Lee 1 *, Soon-gil Jung 2 , Nam Hoon Lee 2 

and Won Nam Kang 2 


2 BK21 Physics Division and Department of Physics, Sungkyunkwan University, 

Korea 

We have studied superconducting transition properties of Ba 0.6K 0.4Fe 2As 2 intergrain 

junctions. The junctions were fabricated by focused ion beam (FIB). Prior to FIB 

patterning, films were prepatterned into microbridges by a standard photolithography 

and argon ion milling technique. The lowest-possible beam current of 1.5 pA was 

used for the FIB pattern to minimize the etching damage to the bridge. The nominal 

dimensions were 200 nm in width and 100 nm in length. Resistive transition, currentvoltage 

(I-V) characteristics, the temperature-dependent critical current (Ic), and the 

normal state resistance (Rn) were measured. Measured transition properties indicated 

that the junctions were dominated mainly by Josephson coupling, showing resistivelyshunted-junction 

(RSJ) behaviors. At higher currents, multiple transitions were 

observed, which might be due to dynamics of Josephson vortices driven by transport 

currents. Details of the measurement results will be discussed. 

RB28 

Coexistence of different electronic phases in the K 0.8Fe 1.6Se 2 

superconductor: a bulk-sensitive hard x-rays spectroscopy study. 

Laura Simonelli 1 *, Naurang L. Saini 2 , Marco Moretti Sala 1 , Y. Mizuguchi 3 , Y. 

Takano 3 , H. Takeya 3 , T. Mizokawa 4 and Giulio Monaco 1 

1 ESRF, France 

2 Dipartimento di Fisica, Universitá di Roma “La Sapienza” - P. le Aldo Moro 2, 00185 Roma, Italy 

3 National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan and JST-TRIP, 1-2-1, Japan 

4 Department of Physics, and Department of Complexity Science and Engineering, University of Tokyo, Japan 

In A xFe 2-ySe 2 (11)-type chalcogenides superconductivity appears to occur only in Fe-deficient samples, 

where the alkali metals are intercalated between the FeSe layers [1-3]. It has been demonstrated how 

the ordering of the Fe vacancies can be correlated to superconductivity and how it can be controlled 

by temperature treatments [2-6]. In particular the superconductivity can be tuned on a single sample 

from an insulating state by post-annealing and fast quenching, and it is tempting to conclude that the 

superconductivity is achieved when the Fe-vacancies are in a disordered state [6]. Here we report on the 

electronic and magnetic structure of K 0.8Fe 1.6Se 2 superconductor by x-ray emission and high resolution 

absorption spectroscopy. We report a study where the electronic and magnetic properties are investigated 

at the same time as a function of temperature in several consistent thermal cycles. We discuss the 

effects of ordered and disordered Fe vacancies on the electronic and magnetic structure, the existence 

of memory effects on thermal cycles, and the relation between electronic and magnetic properties and 

superconductivity. The results obtained are finally compared with the electronic and magnetic properties of 

(11)-type chalcogenides [7]. 

[1] Jing Guo, et al, arXiv: 1101.0092; Y. Kawasaki, et al, arXiv: 1101.0896; J J Ying et al., New J. Phys. 13, 033008 (2011). [2] D. 

M.Wang, et al, arXiv: 1101.0789 . [3] A. M. Zhang, et al, arXiv: 1101.2168v1. [4] Ricci et al. Supercond. Sci. Technol. 24, 082002 (2011). 

[5] Bao Wei et al., Chin. Phys. Lett. 28, 086104 (2011) . [6] F. Han et al., arXiv :11031347. [7] L.Simonelli et al., submitted to PRB. 

RB29 

Step towards a ferromagnetic Josephson junction in YBCO/LCMO 


Soltan Soltan 1 *, Magdy El-hagary 2 , Hanns-ulrich Habermeier 3 and Nasser Alzayed 4 

1 

Physics Department, Faculty of Science, Helwan University, 11792 Helwan, Cairo, 

Egypt 

2 

Physics Department, College of Science,Qassim University, P.O. Box 6644 Buraidah 

51452, Saudi Arabia 

3 

Max-Planck-Institute FKF, Heisenbergstrasse 1, 70569-Stuttgart,, Germany 

4 

Physics Department, King Saud University, Saudi Arabia 

High quality high-Tc superconductor/half metal ferromagnet/high-Tc superconductor 

YBCO/LCMO/YBCO trilayers (SFS) with different orientation of CuO 2 planes in 

superconducting electrodes and different thicknesses of LCMO layers have been 

successfully fabricated by employing pulsed laser deposition techniques. It has been 

found that a LCMO barrier with thickness of 2-3 unit cells is ferromagnetic with a 

Curie temperature close to the bulk value. The strong difference in magnetization loops 

for different SFS-structures measured at T = 5K and the magnetic field parallel to the 

F-layers is caused by the presence of a superconducting current across the ferromagnet 

in the (110) oriented SFS-structure with a thickness of the ferromagnetic layer =1nm. 

This has been confirmed by measuring current-voltage characteristics in patterned 

structures. This sample structure fulfils all prerequisites for the realization of high-Tc 

SFS-Josephson junctions.

RC01 

DMFT study of the correlation effects on a topological insulator 

Tsuneya Yoshida*, Satoshi Fujimoto and Norio Kawakami 

Department of Physics, Kyoto University, Japan 

Recently, topological insulators are theoretically proposed in correlated electron 

systems (e.g. Iridium oxides, Heusler compounds, and filled skutterudites)[1]. The 

correlation effects on the topological insulators are expected to produce exotic states [2] 

and are extensively studied. The strong Coulomb interaction could drive the non-trivial 

band insulator into a Mott insulator. In this paper, we study an extended Bernevig- 

Hughes-Zhang model[3] including the on-site Coulomb interaction with DMFT. 

We calculate the double occupancy at each orbital and the spin-Hall conductivity 

which clearly distinguishes the trivial and non-trivial phases in our model. From the 

analysis of these quantities, it is concluded that the topological insulator changes into 

a trivial nonmagnetic Mott insulator via a first-order transition [4]. Therefore, the 

gap closing does not occur at the transition. In the presentation, we also address the 

antiferromagnetic instability. 

[1] A. Shitade et al., Phys. Rev. Lett. 102, 256403 (2009), S. Chadov et al., Nature Materials 9 541- 

545 (2010), B. Yan et al., arXiv 1104.0641. [2] D. A. Pesin et al., Nature Physics 6, 376 - 381 (2010) 

. [3] B. A. Bernevig et al., Science 314 1757 (2006). [4] T. Yoshida et al., arXiv 1111.6250. 

RC02 

Self-consistent treatment of fully relativistic effect in the small bismuth 

clusters Bin (2≤ n ≤ 7) 

Ely Aprilia 1 *, Haruki Katou 2 , Junpei Gotou 2 , Shinya Haraguchi 2 , Suprijadi Haryono 3 

and Tatsuki Oda 4 

1 

Double Degree Program of Kanazawa university-Bandung Institute of Technology, 

Indonesia 

2 

Graduate School of Natural Sciences and Technology, Kanazawa University, Japan 

3 

Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Indonesia 

4 

Institute of Science and Engineering, Kanazawa University, Japan 

The energy scale of spin-orbit (SO) interaction reaches to the order of 0.1-1eV at the elements in the fifth low 

of periodic table. Such interaction could cause effects on structural properties as well as on electronic ones. 

Bismuth has been investigated by many researchers due to its largeness of SO coupling. Rashba effect, which 

appears as the spin state splitting of surface bands, has been discussed intensively in the system which consists of 

bismuth [1]. The phenomena which are related with new physics of topological insulator have been investigated 

in a lot of bismuth systems [2]. In this context, bismuth clusters are interesting to investigate including relativistic 

effects. In this work, we have studied structural and electronic properties in small bismuth clusters; Bi_n (2 ≤ n 

≤7). The Car-Parrinello molecular dynamics [3] and self-consistent fully relativistic calculations [4,5] have been 

employed to investigate effects of SO coupling effects. It has been found that the clusters of odd number atoms 

were found to carry magnetic moment with non-collinear magnetic configuration. 

[1] Yu. M. Koroteev et al., Phys. Rev. Lett. 93, 046403 (2004). [2] Hsieh et al., Nature 452, 970 (2008). 

[3] R. Car and M. Parrinello, Phys. Rev. Lett. 55, 2471 (1985). [4] T. Oda, A. Pasquarello, and R. 

Car, Phys. Rev. Lett. 80, 3622 (1998). [5] T. Oda and A. Hosokawa, Phys. Rev. B 72, 224428 (2005). 

RC03 

Hidden topological order in URu 2Si 2 

Tanmoy Das 

Theoretical Division, Los Alamos National Laboratory, USA 

UPGRADED 

RC04 

RC05 

RC06 


Ground-state properties of a two-dimensional correlated topological 

insulator 

Yuto Takenaka* and Norio Kawakami 

Department of Physics, Kyoto University, Japan 

Recently, the topological band insulator (TBI) has attracted much interest in condensed 

matter physics. The TBI is characterized by a nontrivial band structure, which has a 

full insulating gap in the bulk and gapless edge states on the boundaries. While the 

essential features of the TBI can be described as a one-body problem, there is much 

interest in the correlation effects on the TBI. In this study, we investigate a generalized 

Bernevig-Hughes-Zhang model having electron correlations with the variational 

Monte Carlo (VMC) method. In order to study how interactions affect the edge states 

and bulk states, it is important to consider inhomogeneous nature due to the lack of 

translational symmetry perpendicular to the boundaries. For this purpose, we introduce 

spatially-dependent variational parameters. We calculate the ground-state energy and 

the momentum distribution to discuss how the correlation effects affect electronic 

properties in the TBI. 

[1] B. A. Bernevig, T. L. Hughes and S. C. Zhang, Science 314, 1757 (2006). 

Magnetic impurity doping effect on bulk Rashiba spin splitting system 

BiTeI 

Jeongdae Seo and Jong- Soo Rhyee* 

Applied Physics, Kyung Hee Universty, Korea 

WITHDRAWN 

Topological charge pumping effect by the magnetization dynamics on 

the Surface of 3D Topological Insulators 

Hiroaki T Ueda 1 *, Akihito Takeuchi 1 , Gen Tatara 1 and Takehito Yokoyama 2 

1 Department of Physics, Tokyo Metropolitan University, Japan 


We discuss a current dynamics on the surface of a 3-dimensional topological insulator 

induced by magnetization precession of a ferromagnet attached. It is found that the 

magnetization dynamics generates a direct charge current when the precession axis is 

within the surface plane. This rectification effect is due to a quantum anomaly and is 

topologically protected. The rectified current is useful in the sense that a direct current 

is easy to detect experimentally. To see the effect of the fast-varying exchange field, we 

study the current dynamics by the topological field theory. We adopt the dimensional 

regularization to regularize the ultraviolet divergence, which is inevitable to study an 

electromagnetic response of a topological insulator. As a result, the robustness of the 

rectification to the fast-varying exchange field is confirmed. 


Poster Thursday



RC07 

Tuning of carrier type in Mn-doped Bi 2Se 3 

Young Ha Choi 1 , Nahyun Jo 1 , Kyujoon Lee 1 , Jumpei Kajino 2 , Toshiro Takabatake 2 

and Myung- Hwa Jung 1 * 


2 ADSM, Hiroshima University, Japan 

Bi 2Se 3 is a good candidate for studying thermoelectric material as well as topological insulator. 

[1] In order to promote the thermoelectric performance, it is good to connect two materials in 

series with different charge carrier type. In Bi 2Se 3, the Se vacancies are dominant, which leads 

to n-type charge carriers.[2] In order to tune the carrier type and carrier density, we have doped 

Mn into Bi 2Se 3 and have studied their physical properties, mainly focusing on the thermoelectric 

properties. The single crystals of MnxBi 2-xSe 3 (x=0.03, 0.05, 0.09 and 0.15) were grown by 

melting the stoichiometric elements in an evacuated quartz ampoule. The Hall and thermoelectric 

measurements illustrate the change of carrier type from n to p type between x=0.03 and 0.05. The 

transport measurements have shown the metallic behavior for x≤0.03 and nonmetallic behavior for 

x≥0.05 at low temperatures. This supports that the Fermi level of p-type samples lies in the surface 

state between the bulk valence band maximum and the bulk conduction band minimum.[3] The 

Seebeck coefficient increases linearly up to ~100μV/K at room temperature both n- and p-type 

samples. This implies that Mn-doped Bi 2Se 3 is possible materials for thermoelectric application. 

[1] D.M. Rowe, in : D.M. Rowe (Ed.), CRC Handbook of Thermoelectrics, CRC Press, Boca Raton, FL, 1995, p 90. [2] N. 

P. Butch, K. Kirshenbaum, P. Syers, A. B. Sushkov, G. S. Jenkins, H. D. Drew, and J. Paglione, Phys. Rev. B. 81, 241301(R) 

(2010). [3] Y. L. Chen, J.-H. Chu, J. G. Analytis, Z. K. Liu, K. Lgarashi, H.-H. Kuo, X. L. Qi, S. K. Mo, R. G. Moore, D. H. 

Lu, M. Hashimoto, T. Sasagawa, S. C. Zhang, I. R. Fisher, Z. Hussain, and Z. X. Shen, Science 329, 659 (2010). 

RC08 

Magnetic edge profile in the Kane-Mele-Hubbard model 

Hyeong Jun Lee 1 , Moo Young Choi 1 and Gun Sang Jeon 2 * 

1 

Department of Physics and Astronomy and Center for Theoretical Physics, Seoul 

National University, Korea 

2 

Department of Physics, Ewha Womans University, Korea 

We investigate the magnetic state on the edge of the Kane-Mele-Hubbard model. The 

ferromagnetic edge states are induced in a graphene nanoribbon by electron-electron 

interactions while certain spin-orbit interactions are known to give rise to a gapless 

current-flowing state on the edge without electron-electron interactions. We use the 

Hartree-Fock approximation to examine the nature of edge states in the presence of 

the Hubbard interaction in the Kane-Mele model. Computing the local magnetization 

of a nanoribbon with various widths, we obtain the edge phase diagram with four 

different phases for the ribbons of finite width and study how the magnetic properties 

are affected by electron-electron interactions. In particular, we show that the edge 

magnetic order survives for weak spin-orbit interactions in the thermodynamic limit. 

The edge magnetic order penetrates towards the ribbon center. The resulting magnetic 

profile gives its characteristic length which is found to be strongly affected by both 

electron-electron and spin-orbit interactions. Variations of its characteristic length turn 

out to be closely related to the phase transition between the topological insulator and 

the antiferromagnetic insulator. Electron dispersions are also discussed. 

RC09 

Theoretical study of spin texture in the Bi thin film 

Hiroki Kotaka 1 *, Fumiyuki Ishii 2 and Mineo Saito 2 


2 Faculty of Mathematics and Physics, Kanazawa University, Japan 

The Spin-Orbit interaction (SOI) is very important effect for heavy atom like Bismuth. 

Recently, first-principles study revealed that significant SOI effects on the electronic 

structure and lattice bistability of Bi nanofilms.[1] In this study, we perform firstprinciples 

electronic structure calculations under the electric field for Bismuth thin film 

and Bi (001) multi-layer surface. We revealed that the SOI combined with electric field 

(so called Rashba effect) is very important in Bi surface state and Bi edge state.[2] We 

calculate spin polarization and spin direction for each band and k-points. Recently, 

giant out-of-plane spin component on Bi (001) surface is discovered SR-ARPES 

experiment.[3] We also calculate the spin structure of multi-layer Bi (001) surface, and 

our calculated result shows the detail of spin features at each k-point. 

[1] H. Kotaka et al., e-JSSNT, Vol.7, pp.13-16, (2009). [2] H. Kotaka, F. Ishii, M. Saito, T. Nagao, 

and S. Yaginuma, JJAP (2012). [3] A. Takayama et al., Phys. Rev. Lett. 106, 166401 (2011). 


RC10 

A recipe for new Topological Insulators based on bonds, bands, 

symmetry and heavy atoms 

Lukas Muechler 1 , Binghai Yan 2 , Stanislav Chadov 3 , Haijun Zhang 4 , Frederick Casper 1 , 

Shoucheng Zhang 4 and Claudia Felser 3 * 

1 Inst. fuer Anorg. Chemie, Johannes Gutenberg - Universitaet Mainz, Germany 

2 Bremen Center for Computational Materials Science, Germany 

3 Max-Planck-Institut fur Chemische Physik fester Stoffe, Germany 

4 Department of Physics, Stanford University, USA 

In this work we will present a recipe to find new Topological Insulators (TIs) based 

on bonds, bands, symmetry and heavy atoms. A big issue concerning the compounds 

known up to now is the control of the bulk carrier density to produce truly insulating 

samples in the bulk. Using concepts from chemistry and supported by densityfunctional 

calculations, we want to motivate an extended search for new compounds 

with tunable bulk properties. 

RC11 

Optimizing the Bi 2-xSb xTe 3-ySe y solid solutions to approach the intrinsic 

topological insulator regime 

Zhi Ren*, Alexey Taskin, Satoshi Sasaki, Kouji Segawa and Yoichi Ando 

ISIR, Osaka University, Japan 

Three dimensional (3D) topological insulators represent a new quantum state of mater 

realized in band insulators, which are predicted to present novel surface transport phenomena. 

In reality, while a number of materials have been identified to be 3D TIs, most of them are 

poor insulators in the bulk. Given this situation, search for new TI materials better suited for 

achieving the bulk insulating state is of obvious importance. In this presentation, we show 

that there exist a series of “intrinsic” compositions for Bi 2-xSb xTe 3-ySe y solid solutions where 

the acceptors and donors compensate each other and present a maximally bulk-insulating 

behavior. At such compositions, the resistivity can become as large as several Ωcm at low 

temperature, and one can infer th role of the surface-transport channel in the nonlinear 

Hall effect[1]. In particular, in the composition of Bi 1.5Sb 0.5Te 1.7Se 1.3, one can achieve a 

surface-dominated transport where the surface channel contributes up to 70% of the total 

conductance[2]. In addition, angle-resolved photoemission spectroscopy reveal that the Dirac 

cone dispersion changes systematically so that the Dirac point moves up in energy with 

increasing x, leading to a sign change of the Dirac carriers at x~0.9[3]. 

[1] Z Ren, A.A. Taskin, S. Sasaki, K. Segawa, and Y. Ando, Phys. Rev. B 84, 165311 (2011). (Editors’ 

Suggestion) [2] A.A. Taskin, Z. Ren, S. Sasaki, K. Segawa, and Y. Ando, Phys. Rev. Lett. 107, 016801 

(2011). [3] T. Arakane, T. Sato, S. Souma, K. Kosaka, K. Nakayama, M. Komatsu, T. Takahashi, Z. 

Ren, K. Segawa, and Y. Ando, Nat. Commun., in press. 

RC12 

Exploration of Three-dimensional Rashba Materials 

Manabu Kanou* and Sasagawa Takao 


Strong spin-orbit interactions under the broken space inversion symmetry can induce 

spontaneous spin polarization without external magnetic fields, which is known as 

the (surface/interface) Rashba effect. On the other hand, due to the lack of a model 

compound, the Rashba effect in three-dimensions (bulk) has been poorly explored. 

In this study, it is demonstrated that ternary compounds of bismuth tellurohalides, 

BiTeX (X = Cl, Br, and I), are promising candidate compounds as ideal threedimensional 

Rashba materials. As the essential backbone for both fundamental and 

applied research, this study established the growth of their sizable single crystals (> 

1 × 1 × 0.2 mm 3 ). Furthermore, it was found that, for BiTeI, that electronic state (the 

carrier concentration) can be adjusted from metallic to insulating ones by the choice 

of the growth techniques. Realization of the 3D Rashba states, including the Fermi 

surface topology for the corresponding carrier concentrations of the obtained crystals, 

was confirmed by relativistic first-principles calculations. We will discuss that our 

3D Rashba materials can be a leading player in spin-involved novel phenomena, 

ranging from the metallic extreme (unconventional superconductivity) to the transport 

intermediate (spin Hall effects) to the novel insulating variant (3D topological 

insulating states).

RC13 

Quantum phase transition from normal to topological insulator phase 

in Na 2IrO 3 

Choong H. Kim 1 , Heung Sik Kim 1 , Hogyun Jeong 2 , Hosub Jin 3 and Jaejun Yu 1 * 

1 Department of Physics and Astronomy, Seoul National University, Korea 

2 Korea Institute of Science and Technology Information, Korea 

3 Department of Physics and Astronomy, Northwestern University, USA 

Na 2IrO 3 has been suggested to have a possible quantum spin Hall effect based on 

the novel jeff=1/2 state arising from the 5d Ir states. From the electronic structure 

calculation analysis of the band topology of Na 2IrO 3, however, it turns out that Na 2IrO 3 

as it is should be a trivial insulator. We investigated the electronic structure of by 

employing a tight-binding model for the layered iridium oxides with honeycomb 

lattice. Our analysis for the layered iridates reveals that the topological nature of the 

spin-orbit coupled ground state depends on the trigonal crystal field and long-range 

hoppings. From the first-principles-derived tight-binding Hamiltonian we determine 

the phase boundary through the parity analysis and predict a quantum phase transition 

from normal to topological insulator. It is suggested that Na 2IrO 3 can be a candidate 

material which can have both non-trivial topology of bands and strong electron 

correlations. 

RC14 

Self-assembled nanowire with giant Rashba spin splitting 

Jewook Park, Min-cherl Jung, Sung Won Jung and Han Woong Yeom* 

Department of physics, POSTECH, Center for atomic wires and layers(CAWL), 

Korea 

We found gaint Rashba-type split bands for Pt-induced nanowires on the Si(110) 

surface by angle resolved photoemission spectroscopy (APRES) measurements. The 

observed Rashba parameter is about 2.1eVA, which is among the largest ever reported 

for Rashba systems and is unique in one-dimensional systems. Pt-induced nanowires 

were also investigated by scanning tunneling microscopy (STM) and scanning 

tunneling spectroscopy (STS) at low temperature (78K). High resolution STM 

topography images show that the wire has a width of 1.6nm and a X3 superstructure 

along the wire. On the other hands, the STS measurements reveal well resolved local 

density of states (LDOS) with a peak at -200meV and a characteristic dip at -300meV 

on the nanowire. These peak and dip energies corresponds well to the ARPES data; the 

top edge and the Dirac-like crossing point energy of the Rashba-type spin split bands, 

respectively. Furthermore, based on the dI/dV spectroscopic mapping, we confirmed 

noticeable one-dimensional electron channels along the nanowire edges, which are 

related to the gaint Rashba band. This implies a future application of the Pt-induced 

nanowire structure in silicon-based spintronics devices. 

RC15 

Ab initio study of topological surface state on Sb (111) surface with 

iron impurities 

Jinhee Han, Hyungjun Lee and Hyoung Joon Choi* 

Department of Physics and IPAP, Yonsei University, Korea 

We study iron impurities on Sb (111) surface and their effects on topological surface 

state by using an ab-initio pseudopotential density-functional method. We implemented 

the spin-orbit interaction into the SIESTA in a form of additional fully non-local 

projectors. To calculate electronic structure of topological surface states, we consider 

a slab of Sb using a supercell containing 20 atomic layers with experimental bulk Sb 

lattice parameters. We determine atomic positions of Fe impurities on Sb (111) surface 

by minimizing the total energy, and calculate surface band structures near the Fermi 

level. To find the impurity effects on the electronic structure of the surface states, we 

simulate ARPES spectra as a function of impurity density on the surface and calculate 

local density of states (LDOS) near the Fermi level. From the results, we find that Fe 

impurity states are present near Fermi level and they strongly interact with the surface 

states and produce a characteristic feature in LDOS on the top surface Sb layer. This 

work was supported by the NRF of Korea (Grant No. 2011-0018306) and KISTI 

Supercomputing Center (Project No. KSC-2011-C3-06). 

RC16 

RC17 

RC18 


Topological insulating phase in cubic system: tight-binding approach 

Hosub Jin, Jino Im and Arthur J. Freeman 

Department of Physics and Astronomy, Northwestern University, USA 

Recently, much attention has focused on three-dimensional strong topological 

insulators as a new quantum state of matter, such as Bi 2Se 3 and Bi 2Te 3. Here we suggest 

topologically non-trivial electronic structures in cubic systems based on the tightbinding 

analysis. Assuming the well separated s and p states and hopping parameters, 

we can set up an 8x8 tight-binding Hamiltonian, and the trivial to non-trivial 

topological phase transition occurs by tuning the hopping parameters or spin-orbit 

coupling strength. Our tight-binding Hamiltonian is reduced to a 4x4 continuum model 

which is the minimal model to describe the topological phase transition. Topologically 

protected surface states in the slab geometry are also shown within our model. 

Supported by the U.S. D.O.E. 

Topological insulator phase and Kitaev-like anisotropic exchange 

interactions in Li 2IrO 3 

Heung-sik Kim 1 , Choong H. Kim 1 , Hogyun Jeong 2 , Hosub Jin 3 and Jaejun Yu 1 * 


2 Korea Institute of Science and Technology Information, Korea 

3 Department of Physics and Astronomy, Northwestern University, USA 

From first-principles electronic structure calculations results, we set up an effective 

tight-binding Hamiltonian for Li 2IrO 3 by constructing Wannier orbitals of lowenergy 

states near the Fermi level. The Wannier orbitals are found to be quite close 

to the $j_{eff}=1/2$ state, which are recently suggested to exist in many other iridate 

compounds. The model Hamiltonian is characterized bythe nontrivial second and third 

nearest neighbor hopping inside Ir honeycomb lattice as well as relatively small but 

significant inter-layer hopping terms. It is shown that the ratio between the nearest and 

third nearest neighbor hopping determines the $Z_2$-invariant of this material, and 

that it can be controlled by the lattice strain in our first-principles calculations. We also 

suggest realistic exchange interactions from effective Hamiltonian, which has various 

nontrivial terms including the most strong Kitaev-type anisotropic exchange terms 

within the same sublattice, rather small but significant Dzyaloshinskii-Moriya terms, 

and Heisenberg exchange interactions. 

Structural and electrical properties of (111) oriented half-Heusler La- 

Pt-Bi thin films 

Nozomi Sugimoto 1 *, Yohei Niimi 1 , Tetsuya Miyawaki 1 , Tatsuhiko Yoshihara 1 , Naoto 

Fukatani 1 , Kenji Ueda 1 , Nobuo Tanaka 2 and Hidefumi Asano 1 

1 Department of Crystalline Materials Science, Nagoya University, Japan 

2 EcoTopia Institute, Nagoya University, Japan 

Topological insulators are candidate materials for low-power and high-speed spintronics 

devices, due to the dissipation less and spin-polarized electrons on the surface state. 

Recently, we have reported structural properties of LaPtBi(001) thin films, one of 

candidate materials of half-Heusler topological insulator[1-2], grown by three-target 

co-sputtering[3]. In this paper, we report preparation and properties of LaPtBi with 

different crystalline orientation.By optimizing deposition rate for each element, (111) 

oriented LaPtBi thin films were obtained below 500°C on Sapphire-C substrates. On 

the other hand, for films on YAlO 3 substrates, both (001) and (111) orientations were 

observed below 500°C. X-ray photoelectron spectroscopy study is revealed that (111) 

oriented films exhibited chemical shifts and appearance of satellite peaks of La 3d, 

which are attributed to charge transfer from Bi p and Pt d states to La d and f states due 

to the mixture of these states in the valence band. Investigation and comparison of the 

behaviors of LaPtBi thin films with different orientations will enable us to uncover the 

electron and spin transport properties in the surface state due to the topological nature. 

[1] S. Chadov et al., Nat. Mater. 9, 541 (2010). [2] H. Lin et al., Nat. Mater. 9, 546 (2010). [3] T. 

Miyawaki et al., J. Appl. Phys., accepted. 


Poster Thursday



RC19 

First-principles study of spin texture in the multilayer graphene on 

Ni(111) 

Fumiyuki Ishii 1 *, Hiroki Kotaka 2 , Keisuke Sawada 3 and Mineo Saito 1 



3 Graduate School of Natural Science and Technology,, Kanazawa University, Japan 

Graphene, a two-dimensional honeycomb lattice consisting of C atoms, shows useful 

properties for spintronics applications. Recently, spin-split electronic states in the 

graphene on Ni(111) is discussed extensively [1-3]. By using noncollinear spindensity 

functional theory implemented in openmx code[4], we predict spin-polarized 

electronic states of the graphene on Ni(111) in real- and momentum-space. The Diraccone 

shaped band structure was broken by strong hybridization between monolayer 

graphene and substrate Ni(111). On the other hand in the bilayer graphene on Ni(111), 

the Dirac-cone shaped band recover only in minority spin. The relativistic spin-orbit 

effect make non-collinear spin vortex (Rashba Effect) in the momentum space. This 

spin noncollinearity in momentum space may make significant effects on the electrical 

transport properties of the graphene/Ni(111). 

[1] Yu. S. Dedkov, M. Fonin, U. Rudiger, and C. Laubschat, Phys. Rev. Lett. 100, 107602 (2008). [2] 

O. Rader, A. Varykhalov, and J. Sanchez-Barriga, D. Marchenko, A. Rybkin, and A. M. Shikin, Phys. 

Rev. Lett. 102, 057602 (2009). [3] K. Sawada, F. Ishii, M. Saito, Phys. Rev. B 82, 245426 (2010). [4] T. 

Ozaki, H. Kino, J. Yu, M. J. Han, N. Kobayashi, M. Ohfuti, F. Ishii, T. Ohwaki, H. Weng, M. Toyoda, 

and K. Terakura, http:// www.openmx-square.org/ 

RD01 

Single Crystal Growth, Electrical and Magnetic Properties in ROs 2Al 10 

(R=rare earth) 

Masahito Sakoda 1 *, Kazuhiro Kubota 1 , Eiichi Matsuoka 1 , Hitoshi Sugawara 1 , 

Takahiro Sakurai 2 , Hitoshi Ohta 3 , Tatsuma D. Matsuda 4 and Yoshinori Haga 4 

1 Department of Physics, Kobe University, Kobe 657-8501, Japan, Japan 

2 Center for Supports to Research and Education Activities, Kobe University, Kobe 657-8501, Japan, Japan 

3 Molecular Photosciece Research Center, Kobe University, Kobe 657-8501, Japan, Japan 

4 Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan, Japan 

The ternary rare-earth compounds ROs 2Al 10 (R = rare earth) crystallize with orthorhombic structure 

[1]. Among them, CeOs 2Al 10 have attracted much attention because of the heavy-fermion behavior 

accompanied by a novel long-range order (LRO) at 28.7 K [2]. In order to understand the mechanisms 

of LRO, the information of physical properties of the reference compounds LaOs 2Al 10 and PrOs 2Al 10 

is required. In this work, we have succeeded in growing single crystals of LaOs 2Al 10 and PrOs 2Al 10 

by Al self-flux method, and investigated the physical properties by the X-ray diffraction, electrical 

resistivity, Hall effect and magnetic susceptibility. Both of LaOs 2Al 10 and PrOs 2Al 10 show the typical 

metallic temperature dependence of electrical resistivity without any indication of phase transitions. 

LaOs 2Al 10 exhibits the Pauli paramagnetism with small temperature dependence, while PrOs 2Al 10 

exhibits the Van Vleck paramagnetism with the Curie-Wiess behavior at high temperature with a large 

magnetic anisotropy, which is most probably due to the crystalline electric field effect. All of these 

results indicate that the electronic structure of CeOs 2Al 10 is different from those of LaOs 2Al 10 and 

PrOs 2Al 10, and suggest that the 4f-electrons in CeOs 2Al 10 are related to the unusual ordering. 

[1] V. M. T. Thieder et al., J. Mater. Chem. 8 (1998) 125. [2] T. Nishioka et al., J. Phys. Soc. Jpn. 78 (2009) 123705. 

RD02 

Anisotropic transport and magnetic properties of CeZn 11 single 

crystals^1$ 

H. Hodovanets, S. L. Bud'ko and P. C. Canfield* 

Department of Physics and Astronomy, Ames Laboratory/Iowa State University, Ames 

IA, USA 

Anisotropic measurements of the magnetic and transport properties have been 

performed on single crystals of CeZn 11 in three different crystallographic directions. 

M(H) for H$\perp c$ shows a broad metamagnetic transition at about 1.9 T with 

Ms~ 1.6 $\mu_B$ per Ce. Analysis of the temperature dependence of M/H indicates 

strong magnetic anisotropy. Zero-field resistivity of CeZn 11 shows a broad maximum, 

characteristic of that of Kondo compounds, at around 10 K followed by a sharp 

change of the slope and a kink corresponding to antiferromagnetic (AF) transition 

at 2.0 K. Anisotropic temperature and field dependent magnetoresistance and H-T 

phase diagrams will be discussed. $^1$ Work at the Ames Laboratory was supported 

by the Department of Energy, Basic Energy Sciences under Contract No. DE-AC02- 

07CH11358. 


RD03 

Shubnikov-de Haas oscillation in PuIn 3 

Yoshinori Haga 1 , Oscar Ayala-valenzuela 2 , Ross Mcdonald 2 , Chuck Mielke 2 , Eric D. 

Bauer 2 , J N Mitchell 2 , P. H. Tobash 2 , Joe D. Thompson 2 and Zachary Fisk 1 



RD04 

Quadrupolar ordering in a caged compound PrOs 2Zn 20 

Kazuhei Wakiya 1 , Naohiro Nagasawa 1 , Keisuke T Matsumoto 1 , Takahiro Onimaru 1 , 

Kazunori Umeo 2 and Toshiro Takabatake 1 

1 AdSM, Hiroshima University, Higashi-Hiroshima, Japan 

2 N-BARD, Hiroshima University, Higashi-Hiroshima, Japan 

Pr-based intermetallic compounds with cubic crystal structures are expected to 

show various phenomena arising from quadrupolar degrees of freedom, when the 

crystal electric field (CEF) ground state of Pr 3+ ion is the nonmagnetic Γ3 doublet. 

Recently, it has been found that a caged compound PrIr 2Zn 20 with the Γ3 doublet 

ground state undergoes a superconducting transition at Tc=0.05 K in the presence of 

antiferroquadrupolar order below TQ=0.11 K [1, 2]. We have studied the isostructural 

compound PrOs 2Zn 20, with 5d electron one less than in PrIr 2Zn 20, by the measurement 

of the electrical resistivity ρ, magnetic susceptibility χ, and specific heat C in the 

temperature range from 0.4 K to 300 K. On cooling below 5 K, χ(T ) approaches a 

constant value, indicating a nonmagnetic CEF ground state. C(T ) shows a peak at 

To=0.6 K, where no anomaly appears in the χ(T ). These findings strongly suggest a 

nonmagnetic phase transition at To arising from the quadrupolar degrees of freedom. 

Furthermore, the To is five times higher than TQ in PrIr 2Zn 20, which is possibly 

attributed to enhancement of quadrupolar exchange interaction. 

[1] T. Onimaru et al., J. Phys. Soc. Jpn. 79 033704 (2010). [2] T. Onimaru et al., Phys. Rev. Lett. 

106 177001 (2011). 

RD05 

UPGRADED 

Spin-triplet superconductivity induced by ferromagnetic fluctuations 

in UCoGe 

Taisuke Hattori 1 *, Yoshihiko Ihara 1 , Kosuke Karube 1 , Yusuke Nakai 2 , Kenji Ishida 2 , Yasuhiro Tada 1 , 

Satoshi Fujimoto 1 , Norio Kawakami 1 , Kazuhiko Deguchi 3 , Noriaki K Sato 3 and Isamu Satoh 4 


2 Department of Physics, Graduate School of Science, Kyoto University. TRIP, JST, Japan 



After the discovery of superconductivity in the ferromagnetic (FM) UGe 2 under pressure, FM 

superconductors have attracted much interest, since in an itinerant FM superconductor with the presence 

of a large energy splitting between the majority and minority spin Fermi surfaces, exotic spin-triplet 

superconductivity has been anticipated. Among such FM superconductors, UCoGe [1] is one of the most 

readily explored experimentally, because of its high superconducting transition temperature ~ 0.7 K and low 

Curie temperature ~ 2.5 K at ambient pressure. Large anisotropic behaviors of superconductivity [2, 3] and 

longitudinal FM fluctuations along the c axis (direction of the ordered moment) [4] are thought to link with 

the mechanism of the superconductivity. From precise angle-resolved NMR and Meissner measurements 

we found that the magnetic field along the c axis strongly suppresses the FM fluctuations and that the 

superconductivity is observed in the limited magnetic field region where the FM spin fluctuations are active. 

These results combined with model calculations strongly suggest that the longitudinal FM spin fluctuations 

tuned by H || c induce the unique spin-triplet superconductivity in UCoGe. As far as we know, this is the first 

clear experimental example that FM fluctuations are intimately related with superconductivity. 

[1] N. T. Huy et al., Phys. Rev. Lett. 99 (2007) 067006. [2] N. T. Huy et al., Phys. Rev. Lett. 100 (2008) 077002. [3] 

D. Aoki et al., J. Phys. Soc. Jpn. 78 (2009) 113709. [4] Y. Ihara et al., Phys. Rev. Lett. 105 (2010) 206403.

RD06 

Competitive magnetic properties between the different anisotropic 

SDW phases in heavy-fermion system Ce 0.87La 0.13(Ru 1-xRh x) 2Si 2 

Hiroaki Okamoto 1 , Eiichiro Harada 1 , Yusuke Amakai 1 , Shigeyuki Murayama 1 *, 

Hideaki Takano 1 , Naoki Momono 1 , Kazuyuki Matsubayashi 2 and Yoshiya Uwatoko 2 



Typical heavy-fermion compound CeRu 2Si 2 shows an SDW transition by the 

substitution of La at the Ce site with the gap perpendicular to the c-axis and the moment 

along the c-axis(1). It shows another SDW transition with the gap and moment both 

parallel to the c-axis by the substitution of Rh at the Ru site(2). In order to investigate 

the two different SDW phases, we have measured the susceptibility χ and resistivity ρ 

on single-crystalline Ce 0.87La 0.13(Ru 1-xRh x) 2Si 2 for 0 ≤ x ≤ 0.4 in directions perpendicular 

(∠) and parallel (//) to the c-axis(3). The ρ∠ for 0 ≤ x < 0.05 shows a gap-type anomaly 

at TN, whereas the ρ// for 0 ≤ x < 0.05 indicates a downward inflection or a shoulder 

at around TN, suggesting the transverse SDW transition. For 0.05 ≤ x ≤ 0.075 these 

anomalies become very small and a hysteresis is further seen between temperature 

decreasing and increaseing process below TN. For 0.075 < x ≤ 0.3 the gap-type anomaly 

in ρ∠ disappears and a clear gap-type jump has been detected in ρ// at TN, suggesting 

the longitudinal SDW transition. These behaviors would suggest that a competitive 

magnetic phase occurs between the two anisotropic SDW phases. 

(1) S. Quezel et. al., J. Magn. & Magn. Mater., 76 & 77, 403 (1988). (2) S. Murayama et. al., Phys. 

Rev. B 56, 11092 (1997). (3) Y. Amakai et. al., J. Phys. Soc. Jpn. 80, SA062 (2011). 

RD07 

Elastic constant of SmOs 4Sb 12 under high magnetic field 

Tatsuya Yanagisawa 1 *, Shota Mombetsu 1 , Mitsuhiro Akatsu 2 , Yuichi Nemoto 2 , Shadi 

Yashin 3 , Sergei Zherlitsyn 3 and Joachim Wosnitza 3 

1 Department of Physics, Hokkaido University, Japan 


3 Dresden High Magnetic Field Laboratory, Forschungszentrum Dresden-Rossendorf, 

Germany 

The filled skutterudite compound SmOs 4Sb 12 exhibits a large electronic specific heat coefficient Υ 

~ 820 mJ K -2 mol -1 , which is insensitive to an applied magnetic field H || , and also shows a 

phase transition at 2.5 K with tiny ferromagnetic moment. The origin of the magnetically robust 

heavy fermion state and an exotic phase transition are unsolved issues. The crystalline electric field 

(CEF) ground state of this compound has also not been settled, thus far. Owing to clarified whether 

the CEF ground state is the Γ_8 quartet or Γ_7 doublet for Sm 3+ ionic configurations, we have 

measured the elastic constant C_11 on single crystalline SmOs 4Sb 12 by using pulsed magnetic 

fields up to 62 T. As a result, C_11 shows a minimum at around 10 T and gradually increase with 

increasing magnetic field at 4.2 K. In the cubic symmetry, C_11 can be described as the sum of 

the bulk modulus C_B and the Γ_3-type quadrupole susceptibility. Assuming that C_B is only 

dominated by magneto-elastic effects of the weak ferromagnetic moment in the low magnetic 

field region, the increasing tendency of C_11 at high magnetic field region could be explained by a 

quadrupole susceptibility with Γ_8 quartet CEF ground state. 

[1] S. Sanada et al., J. Phys. Soc. Jpn. 74 (2005) 246, [2] W. M. Yuhasz et al., Phys. Rev. B 71 (2005) 104402, [3] 

Y. Aoki et al., Physica B 378-380 (2006) 54, [4] T. Yanagisawa et al., J. Phys. Soc. Jpn. 80 (2011) 043601. 

RD08 

27Al-NMR study for critical phenomena of metamagnetic transition in 

UCoAl 

Kosuke Karube 1 *, Taisuke Hattori 1 , Kenji Ishida 1 , Takuya Asai 2 , Takemi 

Komatsubara 3 and Noriaki Kimura 2 


2 Department of Physics, Graduate School of Science, Tohoku University, Japan 

3 Center for Low Temperature Science, Tohoku University, Japan 

UCoAl shows a first-order paramagnetism (PM)-ferromagnetism (FM) transition (metamagnetic 

transition) in small external magnetic field about 0.6 T applied only along its easy magnetization 

axis, c-axis [1]. This first order transition line terminates at a “critical-end-point” at Tcr ~ 13 K. 

Above Tcr the first order transition from PM to FM changes to crossover. This feature is apparently 

similar to gas-liquid transition, where the order parameter and the tuning parameter are density of 

molecules and pressure, respectively. In fact, a gas-liquid transition is regarded to be mathematically 

equivalent to 3D-Ising FM transition [2], therefore we expect the metamagnetic transition in 

UCoAl has the same physical framework as a gas-liquid transition. In order to investigate static and 

dynamic properties in the critical phenomena on UCoAl, we performed 27Al-NMR measurement 

for a single-crystal UCoAl and measured Knight-shift K and nuclear spin-lattice relaxation rate 1/ 

T1 by varying temperature T and c-axis magnetic field Hc. In the poster presentation, I will show 

the result of c-axis magnetization Mc (order parameter) and c-axis dynamical susceptibility Sc 

(fluctuations of order parameter) calculated from K and 1/T1T, as a function of (T, Hc) and discuss 

similarities and differences from comparison with gas-liquid transition. 

[1] N. V. Mushinikov et al., Phys. Rev. B 59, 6877 (1999). [2] T. D. Lee et al., Phys. Rev. 87, 410 (1952). 

RD09 

RD10 

RD11 


Hybridization gap and the hidden order in the heavy fermion Kondo 

lattice URu 2Si 2 

Wan Kyu Park 1 *, Paul H. Tobash 2 , Filip Ronning 2 , Eric D. Bauer 2 , John L. Sarrao 2 , 

Joe D. Thompson 2 and Laura H. Greene 1 

1 University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA 

2 Los Alamos National Laboratory, Los Alamos, NM 87545, USA 

What drives the second order phase transition that occurs at 17.5 K in the Kondo lattice 

heavy fermion URu 2Si 2 remains unknown after two and half decades of research despite 

ubiquitous observation of gap-like behaviors. Determining the nature of the extracted 

gaps, whether they are the order parameter or not, is a crucial task to resolving this hidden 

order enigma. Quasiparticle scattering spectroscopy (QPS), better known as pointcontact 

spectroscopy, is a powerful technique to probe the bulk electronic properties by 

exploiting a ballistic junction between two electrodes. Employing QPS, we have carried 

out conductance measurements on URu 2Si 2 [1]. The differential conductance data exhibit 

a distinct double-peak structure with pronounced asymmetry, a signature for a Fano 

resonance in a Kondo lattice [2]. The extracted gap, a hybridization gap between the 

renormalized bands, opens well above the hidden order transition temperature, indicating 

this hybridization gap is not the hidden order parameter. Our results place severe 

constraints on the origin of the hidden order transition in URu 2Si 2. The work at UIUC is 

supported by the U.S. DOE under Award No. DE-FG02-07ER46453. The work at LANL 

is carried out under the auspices of the U.S. DOE, Office of Science. 

[1] W. K. Park et al., PRL 108, 246403 (2012) [2] M. Maltseva, M. Dzero, P. Coleman, PRL 103, 206402 (2009). 

Resonant Raman effect on LaRu2Al10 and CeRu2Al10 Katsuaki Nagano 1 , Takumi Hasegawa 1 , Norio Ogita 1 , Masayuki Udagawa 1 , Hiroshi 

Tanida 2 , Daiki Tanaka 2 , Masafumi Sera 2 , Takashi Nishioka 3 and Masahiro Matsumura 3 

1 

Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi- 

Hiroshima 739-8521, Japan, Japan 

2 

Institute for Advanced Material Research, Hiroshima University, Higashi-Hiroshima 

739-8530, Japan, Japan 

3 

Graduate School of Advanced Sciences of Matter, Kouchi University, Kochi 780- 

8520, Japan, Japan 

LaRu 2Al 10 and CeRu 2Al 10 with space group Cmcm have the orthorhombic YbFe 2Al 10 type structure [1], where 

the number of Raman active phonons is estimated as 10Ag + 9B1g + 6B2g + 8B3g by group theory. CeRu 2Al 10 

shows the transition at T0 = 27 K [2, 3, 4], while LaRu 2Al 10 shows no anomaly. We reported the temperature 

dependence of the phonon Raman spectra at the SCES 2011, where we could not observe all phonon modes by 

only 514.5 nm excitation and no anomaly at T0 in CeRu 2Al 10. We concluded that the transition at T0 does not 

accompany with the structural change. Recently we have employed several excitations light at 488.0 nm, 514.5 

nm, 568.2 nm, and 647.1nm. We have observed the B1g mode missed by only 514.5 nm, that is, we observe all 

phonon modes by changing the excitation energy. In the guest atoms modes, the vibration along b axis shows 

the intensity enhancement at 647.1 nm, but that along a or c axis does not show the case. Remarkable difference 

between LaRu 2Al 10 and CeRu 2Al 10 is observed for the phonons at around 100 cm-1 in (y, z) polarization. These 

differences are originated by the difference of the electronic states between them. 

[1] Thieda V M T, et al, 1998 J. Mater. Chem. 8 125. [2] Strydom A M 2009 Physica B 404 2981 [3] 

Nishioka T, et al 2009 J. Phys. Soc. Jpn. 78 123705 [4] Muro Y, et al 2010 J. Phys.: Conf. Series 200 012136 

Magnetic properties of β-US2 single crystals 

Etsuji Yamamoto 1 *, Shugo Ikeda 2 , Hironori Sakai 1 , Tatsuma D. Matsuda 1 , Naoyuki 

Tateiwa 1 , Yoshinori Haga 1 , Yoshichika Onuki 3 and Zachary Fisk 4 

1 ASRC, Japan Atomic Energy Agency, Japan 




Uranium chalcogenides compounds UXS (X:S, Se and Te) have the same orthorhombic 

(Pnma) structure and those electronic state can easily be modified by changing the 

constituting elements. UTeS is an Ising-type ferromagnet with a Curie temperature 87 

K and shows metallic conductivity at all temperatures. USeS shows a semimetallic 

resistivity. Electrical resistivity of USeS decreases with decreasing temperature 

but increases steeply below 50 K, with an anomaly at the ferromagnetic ordering 

temperature 24 K.US2 is similar to USeS at high temperature and the electrical 

resistivity of US2 decreases with decreasing temperature and increases steeply below 

about 80 K, but US2 does not order magnetically. The electrical resistivity of US2 at 

low temperature suppresses under a high pressure or a high magnetic field [1]. We 

study the magnetic properties of US2 in detail by measuring magnetic susceptibility 

and electric resistivity under a magnetic field. 

[1] S. Ikeda et al., J. Phys. Soc. Jpn.76 (2009) 114704. 


Poster Thursday



RD12 

Evidence of nodal gap structure in the skutteride superconductor 

PrPt 4Ge 12 

Jing Lei Zhang 1 , Lin Jiao 1 , Michael Nicklas 2 , Roman Gumeniuk 2 , Ye Chen 1 , Lu Kai 

Guo 1 , Li Na Wang 1 , Bin Hao Fu 1 , Walter Schnelle 2 , Helge Rosner 2 , Andreas Leithejasper 

2 , Yuri Grin 2 , Frank Steglich 2 and Hui Qiu Yuan 1 * 

1 Department of Physics, Zhejiang University, China 

2 Max Planck Institute for Chemical Physics of Solid, Germany 

In order to study the gap function of the newly discovered skutterudite superconductor 

PrPt 4Ge 12 (T_{c}=7.9K), we have measured the London penetration depth Δλ(T) of the 

single crystalline PrPt 4Ge 12 down to 0.05Tc by using a tunnel diode oscillation (TDO) 

based technique. Observation of a quadratic temperature dependence of Δλ below 

0.3Tc indicates the existence of point nodes in the superconducting gap. The derived 

superfluid density ρ_{s}(T) can be nicely fitted by the A-phase gap function of 3He 

(Δ(θ,φ)=Δ_{0} |K_{x}+iK_{y}|) with a fitting parameter of Δ_{0}=2.2k_{B}T_{c}, 

providing new evidence for a possible p-wave superconductivity in PrPt 4Ge 12. 

RD13 

Mossbauer spectroscopy of Fe doping valence fluctuating α-YbAlB 4 

Yui Sakaguchi1*, Shugo Ikeda1, Kentaro Kuga2, Keita Sone2, Satoru Nakatsuji2 and 

Hisao Kobayashi1 



Valence fluctuating YbAlB 4 compounds have two different crystal structures; α-YbAlB 4 

andβ-YbAlB 4 [1].β-YbAlB 4 is the first compound which shows a Yb-based heavy fermion 

superconductor with Tc = 80mK [2] and exhibits a pronounced non-Fermi-liquid behavior 

above Tc. Meanwhile, α-YbAlB 4 shows normal metallic behaviorsat low temperature. 

Recently, the small substitution of Al by Fe in α-YbAlB 4 revealed a breakdown of 

the Fermi-liquid behavior with an antiferromagnetic order. We have studied magnetic 

properties of α-Yb(Al 0.75Fe 0.25)B 4 at low temperatures using 57Fe Mossbauer spectroscopy. 

The observed Mossbauer spectrum at room temperature using single crystalline samples 

is typical for a paramagnetic state. We analyzed the spectrum using a doublet. From 

the intensity ration of the doublet, the principle z-axis of the diagonalized electric-field 

gradient tensor is perpendicular to the c-axis. We observed a small magnetic hyperfine 

field at 4.5K whitch comes from the antiferromagnetic ordering of Yb magnetic moments. 

This small magnetic hyperfine field disappears around TN (~ 9K). These results indicate 

that the magnetic structure is not simple in α-Yb(Al 0.75Fe 0.25)B 4. Above TN, the observed 

spectra change drastically with increasing temperature. Some of changes in the spectra 

were related to anomalies in the temperature dependence of magnetization. 

[1] R. T. Macaluso et al., Chem. Mater. 19. 1918 (2007) [2] S. Nakatsuji et al., Nature Phys. 4, 603 (2008) 

RD14 

Neutron scattering study on f-electron states of PrCu 4Au 

Hiroki Kobayashi 1 , Kazuaki Iwasa 1 *, Kotaro Saito 1 , Keisuke Tomiyasu 1 , Daichi 

Kawana 2 , Shuai Zhang 3 , Yosikazu Isikawa 4 , Jean - Michel Mignot 5 , Gilles Andre 5 , 

Alexander I. Kolesnikov 6 , Andrei T. Savici 6 and Garrett E. Granroth 6 

1 Department of Physics, Tohoku University, Sendai 980-8578, Japan 

2 Condensed Matter Research Center and Photon Factory, Institute of Materials Structure 

Science, KEK, Tsukuba 305-0801, Japan 

3 Department of Applied Chemistry, Hiroshima University, Higashi-Hiroshima 739-8527, Japan 

4 Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan 

5 Laboratoire Leon Brillouin, CEA-CNRS, CEA/Saclay, 91191 Gif sur Yvette, France 

6 Neutron Sciences D., Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 

Pr-based compounds have recently been studied for heavy electron properties originating from 4f 2 

electron configuration, as in PrFe 4P 12 [1]. We extracted a large electronic-specific-heat-coefficient of 

0.77 J/mol K 2 from specific heat measurements on PrCu 4Au [2]. This material is expected to undergo 

an antiferromagnetic transition below 2.4 K. We investigate the role that f-electron states play in these 

properties using neutron scattering techniques. We used the spectrometers SEQUOIA at ORNL, 4F1 at 

LLB, and TOPAN at JAEA to measure the temperature dependence, between 1.6 K and 100 K, of the 

magnetic excitations in PrCu 4Au. The spectra are composed of several inelastic peaks. The crystal-fieldsplitting 

scheme with the triplet ground state, as suggested from the magnetization result [2], is a fair match 

to the observed spectra. A quasielastic component was also detected. The temperature dependences of the 

spectral intensity and width are similar to those in other heavy electron systems. Diffraction experiments 

for the powdered sample on the diffractometer G4-1 at LLB reveal antiferromagnetic peaks characterized 

by the wave vector (1/2, 1/2, 1/2). This result can be interpreted as the type-II magnetic ordering on the fcc 

sub-lattice of Pr ions. To summarize, PrCu 4Au exhibits localized and strongly-hybridized f-electron states. 

[1] H. Sugawara et al.: Phys. Rev. B 66 (2002) 134411. [2] S. Zhang et al.: J. Phys.: Condens. Matter 21 (2009) 205601. 


RD15 

Effect of pressure on the YbNi 3Ga 9 single crystal 

T. Hirayama 1 , K. Matsubayashi 1 , T. Yamashita 2 , S. Ohara 2 and Y. Uwatoko 1 * 


2 Nagoya Institute of Technology, Japan 

We have investigated the effect of pressure on the physical properties of singlecrystalline 

YbNi 3Ga 9. This compounds crystallize in a trigonal ErNi 3Al 9-type structure 

(space group R32). From the thermal, magnetic and transport study, YbNi 3Al 9 turns 

out to be an intermediate valence compound with r = 30 mJ/molK [1]. The electrical 

resistivity and ac susceptibility of nonmagnetic heavy fermion compound YbNi 3Al 9 

have been measured under hydrostatic pressure up to 11 GPa. With increasing pressure, 

the ferromagnetic ordering state was appeared over 9 GPa. These results suggested 

that nonmagnetic Yb state change to the localized magnetic state, via quantum critical 

point, by tuning the pressure. In this paper, we will discuss the electrical state of 

YbNi 3Al 9 under pressure. 

[1]T. Yamashita and S. Ohara; submitted to J. Phys. Soc. Jpn. 

RD16 

Fermi surfaces in the mixed valent Yb system 

Hisatomo Harima* 


Many Yb-compounds have been crystalized recently in good quality, so that the de 

Haas-van Alphen effect is detected in those including the Yb-based heavy fermion 

compounds, i.e., YbCu 2Si 2, YbAlB 4. Non-magnetic Yb compounds are regarded 

mostly as divalent Yb system, in which Fermi surfaces are well reproduced by using 

conventional band structure calculations. In some of non-magnetic Yb compounds, 

such as YbAl 3, the valence of Yb-ion is diverted from Yb 2+ . Actually, the Fermi 

surfaces of YbAl 3 are very different in topology from those of divalent YbIn 3. This is 

the clear evidence of the 4f electrons really affect the formation of the Fermi surfaces 

in YbAl 3[1]. In Yb compounds, the dispersion of the 4f bands are very flat, then the 

Fermi surfaces are very sensitive to the role of the 4f electrons. Recently the LDA+U 

approach has shown that only the doublet ground states participate the Fermi surfaces 

in YbCu 2Si 2[2]. The role of 4f electrons in mixed valent Yb system is discussed, for 

YbAlB 4 , YbCoGa 5 and the related compounds. 

[1] T. Ebihara, et.. al., J. Phys. Soc. Jpn. 69 (2000) 895. [2] Nguyen Duc Dung, et. al., J. Phys. Soc. 

Jpn. 78 (2009) 084711. 

RD17 

Unusual heavy fermion behavior in PrTr 2Al 20 (T = Nb, Ta) associated 

with Γ_3 quadrupolar degrees of freedom 

Ryuji Higashinaka, Akihiro Nakama, Ryoichi Miyazaki, Yuji Aoki and Hideyuki Sato 


Recently, PrTr 2X 20 (Tr = transition metal, X = Zn, Al) compounds have attracted 

much attention as a new candidate for investigating the quadrupolar Kondo effect 

because PrTr 2Al 20 (Tr = Ti, V) show non Fermi liquid behaviors and multipolar 

orderings attributed to nonmagnetic Γ_3 doublet ground state[1]. Recently, we found 

that PrNb 2Al 20 also has a nonmagnetic Γ_3 doublet ground state and does not show 

any phase transitions down to 0.15 K[2]. In addition, this compound has a large 

Sommerfeld coefficient γ(~ 1.2 J/molK 2 ). This result suggests a possibility of the 

formation of unusual heavy fermion state attributed to the quadrupole moments of 

Γ_3 state. In order to investigate the quadrupole-induced strongly correlated electronic 

properties in PrTr 2Al 20 systematically we have grown single crystals of other Pr based 

compound, PrTa 2Al 20, and performed specific heat, magnetization and electronic 

transport measurements. In C/T, PrTa 2Al 20 shows a peak around 0.6 K attributed to 

the ordring of quadrupole moment and has a large gamma value of 1.6 J/molK 2 at low 

temperatures with little field dependence. In this presentation, we show recent results 

for PrT 2Al 20 (T = Nb, Ta) and discuss the possibility of the formation of heavy fermion 

formation induced by quadrupolar degrees of freedom. 

[1] A. Sakai and S. Nakatsuji: J. Phys. Soc. Jpn. 71 063701 (2011). [2] R. Higashinaka et al.: JPS 

Autumn meeting 23pPSA-37 (2010), JPS Spring meeting 28aEC-11 (2011).

RD18 

Tuning of the heavy-fermion ground state in YbNi 3X 9 (X=Al, Ga) by 

substitution 

Shigeo Ohara*, Hiroshi Kono and Tetsuro Yamashita 

Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, 

Japan 

We have succeeded in synthesizing new Yb-based Kondo lattice systems YbNi 3X 9 (X =Al, Ga) 

which crystallizes in the trigonal ErNi 3Al 9-type structure [1]. YbNi 3Al 9 shows typical features 

of a heavy-fermion antiferromagnet with Neel temperature of TN=3.4K and Sommerfeld 

coefficient γ~100mJ/(molK2). In contrast, YbNi 3Ga 9 is an intermediate valence compound with 

γ=30mJ/(molK2) and a high characteristic temperature of TK~600K. YbNi 3X 9 (X =Al, Ga) 

is a great opportunity to investigate the tunability of heavy-fermion ground states in Yb-based 

compound for using external control parameters such as pressure or doping. In this regard, we 

are investigating physical properties of mixed crystals of YbNi 3Al 9-YbNi 3Ga 9, doping system of 

Yb(Ni 1-xM x) 3X 9 (M=3d transition-metal) and dilute system of (Yb 1-xLu x)Ni 3X 9. Here we report 

Ni-site substitution effects on the antiferromagnetism of YbNi 3Al 9. For YbNi 3Al 9, the resistivity 

shows a -logT dependence below 100K and a broad peak at about 40 K arising due to the Kondo 

effect combined with the CEF excited state. In the lower-temperature region, a strong reduction 

in the extent of magnetic scattering associated with the antiferromagnetic ordering was observed 

below TN=3.4 K. By Fe-substitution TN is decreased, while is increased by Cu-substitution. The 

tunability of TN in Yb(Ni 1-xM x) 3X 9 will be discussed. 

[1] S. Ohara et al., J. Phys.: Conf. Series 273, 012048 (2011); T. Yamashita et al., to be published in 

J. Phys. Soc. Jpn. 

RD19 

Pressure effect studies in Ce 2T 3Ge 5 (T=Rh, Pd, Ir) by electrical 

resistivity 

Miho Nakashima 1 , Toshiyuki Uchiyama 1 , Toru Kawata 1 , Yasushi Amako 1 , Yusuke 

Hirose 2 , Honda Fuminori 2 , Rikio Settai 2 and Onuki Yoshichika 2 

1 Department of Physics, Faculty of Science, Shinshu University, Japan 


In the Ce 2T 3Ge 5 system (T: transition metal) with the orthorhombic crystal structure, Ce 2Ni 3Ge 5 

is an antiferromagnet with a Neel temperature T N = 5.2 K. T N decreases with increasing pressure 

and becomes zero at a critical pressure P c = 3.9 GPa. The A and ρ 0 values in the Fermi liquid 

relation (the low-temprature electrical resistivity ρ = ρ 0 + AT 2 ) increase steeply above 3 GPa. 

It seems to be the heavy fermion state around Pc, in which pressure region superconductivity 

was found below 0.26 GPa [1]. We measured temperature dependence of electrical resistivity 

of Ce 2Rh 3Ge 5, Ce 2Ir 3Ge 5 and Ce 2Pd 3Ge 5 under pressure in this study. These theree compounds 

are all antiferromagnets at ambient pressure, showing kinks of resistivity at T N (=4.7, 9.5 and 

3.8 K respectively)[2, 3, 4]. In Ce 2Rh 3Ge 5 and Ce 2Ir 3Ge 5 T N decreases with increasing pressure 

and seems to be zero at a critical pressure P c=0.4 and 2.0 GPa, while T N increases in Ce 2Pd 3Ge 5 

by pressure. We also found another anomaly at lower temperature, indicating T N splits into 

two ordering T N1 and T N2 under pressure more than 0.2 GPa. T N 1 and T N 2 are both increasing 

monotonously with increasing pressure up to 2.3 GPa. 

[1] M. Nakashima, et al., J. Phys.: Condens. Matter 17 (2005) 4539. [2] C. Godart, et al., Solid 

State Commun. 67 (1988) 677. [3] B. Becker, et al., Phys. B 230-232 (1997) 253. [4] Z. Hossain, et 

al., Phys. Rev. B 60 (1999) 10383. 

RD20 

Photoemission study on new Kondo lattice compounds YbNi 3(Ga 1-xAl x) 9 

Yuki Utsumi 1 , Hitoshi Sato 2 , Shigeo Ohara 3 , Tetsuro Yamashita 3 , Kojiro Mimura 4 , 

Satoru Motonami 4 , Masashi Arita 2 , Shigenori Ueda 5 , Keisuke Kobayashi 5 , Kenya 

Shimada 2 , Hirofumi Namatame 2 and Masaki Taniguchi 2 

1 Graduate School of Science, Hiroshima University, Japan 

2 Hiroshima Synchrotron Radiation Center, Hiroshima University, Japan 

3 Graduate School of Engineering, Nagoya Institute of Technology, Japan 

4 Graduate School of Engineering, Osaka Prefecture University, Japan 

5 NIMS Beamline Station at SPring-8, National Institute for Materials Science, Japan 

Recently, new Kondo lattice compounds YbNi 3X 9 (X=Al, Ga) were discovered [1]. YbNi 3Al 9 is a heavyfermion 

antiferromagnetic compound (TN=3.4 K), while YbNi 3Ga 9 is a valence fluctuating compound from 

the magnetic susceptibility measurements. These compounds are considered to be very suitable for research 

of Yb-based Kondo lattice systems because they both possess the ErNi 3Al 9-type crystal structure, and the Al 

and Ga ions are isovalent. In this study, we have carried out hard x-ray (hν~6 keV) and low energy (hν~7 eV) 

excited photoemission spectroscopy (HAXPES and LEPES) on YbNi 3X 9 and mixed crystals YbNi 3(Ga 1-xAl x) 9 

to investigate the Yb valence and the Kondo resonance behavior. The Yb 3d HAXPES experiments revealed 

that the Yb ion in YbNi 3Al 9 exists with almost trivalent state while that in YbNi 3Ga 9 strongly fluctuates with 

the averaged Yb valence of ~2.5. The Al substitution for YbNi 3Ga 9 (x~0.1) changes the Yb ion toward trivalent 

state. The LEPES spectra of YbNi 3Ga 9 clearly exhibit the Kondo resonance peak near the Fermi level (EF), 

and the peak is shifted toward EF and the intensity increases with lowering temperature. The extrapolated peak 

energy at zero temperature provides TK~600 K for YbNi 3Ga 9 and the Al substitution lowers TK. 

[1] S. Ohara et al., J. Phys.: Conf. Series 273, 012048 (2011); T. Yamashita et al., to be published in J. Phys. Soc. Jpn. 

RD21 

RD22 

RD23 


Heavy-fermion properties of YbCu5-xAux (x = 0.5, 0.6, 0.7) 

Ivan Curlik 1 *, Mauro Giovannini 2 , Mariana Zapotokova 3 and Marian Reiffers 1 

1 

Institute of Experimental Physics, Slovak Academy of Science, Watsonova 47, 040 

01, Kosice, Slovakia, Slovak 

2 

CNR-SPIN and Department of Chemistry, University of Genoa, Via Dodecaneso 31, 

16 146, Genoa, Italy, Italy 

3 

Institute of Experimental Physics, Slovak Academy of Science, Watsonova 47, 040 

01, Kosice, Slovakia, Slovak 

Yb compounds are very attractive for research because of their low temperature 

anomalous behaviour. Recently, emphasis was given to the investigation of the solid 

solution YbCu 5-xM x (M = Ag, Au, In) crystallizing in the cubic AuBe 5-type structure. 

The substitution of Cu by M offers the possibility of studying the different evolutions 

of the ground state depending on the M element (e.g. a valence transition in M = In, 

Kondo-lattice behavior in M = Ag, magnetic ordering in M = Au) [1,2,3]. Here we 

present the measurements of heat capacity and resistivity in the temperature scale 0.4 

-300 K for different applied magnetic fields 0 - 9 T of the YbCu 5-xAu x (x = 0.5, 0.6, 0.7) 

system. The polycrystalline samples were prepared by induction-melting method, heattreated 

and then quenched in cold water. Phase purity was checked by electron probe 

microanalysis (EPMA) and X-ray diffraction (XRD) 

[1] K. Yoshimura et al., J. Alloys Comp 262-263 (1997) 118 [2] M. Galli, E.Bauer, St. Berger, Ch. 

Dusek et al. Physica B 312-313 (2002) 489 [3] J. He, N. Tsujii et al., J. Phys. Soc. Jpn 66 (1997) 

2481 

Magetic properties of heavy-fermion compounds Ce 1-xLu xRu 2Si 2 

Toru Sekiguchi 1 , Yusuke Amakai 1 , Shigeyuki Murayama 1 *, Hideaki Takano 1 , Naoki 

Momono 1 , Kazuyuki Matsubayashi 2 and Yoshiya Uwatoko 2 



Typical heavy-fermion compound CeRu 2Si 2 with a tetragonal structure shows an 

antiferromagnetic transition by the substitution of La at the Ce site due to the negative 

chemical pressure by the larger La ion(1). The substitution of Y introduces a decrease 

of the specific heat coefficient γ and an increase of the Kondo temperature TK due to 

the positive chemical pressure by the smaller Y ion(2). In order to study substitution 

effect of Lu with the closed f-electron shell and the ion smaller than Y, we have 

measured the susceptibility χ and resistivity ρ on single-crystalline Ce 1-xLu xRu 2Si 2 for 

0≤x≤0.2 perpendicular (∠) and parallel (//) to the c-axis.The χ// shows a maximum 

and the Tmax increases with x. Since the Tmax is supposed to be the heavy-fermion 

formation temperature proportional to 1/γ, the effective mass meff is considered 

to increase with x. The resistivity ρ shows a shoulder by the Kondo effect and the 

Tshoulder increases with x. This indicates an increase of TK due to the positive 

chemical pressure by Lu. The low temperature resistivity follows the T 2 law and the 

coefficient A decreases with x. Since A is proportional to γ 2 , meff is again considered to 

increase with x. 

(1) S. Quezel et. al., J. Magn. & Magn. Mater., 76 & 77, 403 (1988). (2) M.J. Besnus et. al., J. Magn. 

& Magn. Mater., 63 & 64, 323 (1987). 

Moment-bearing Tb substitution in CePt 2Si 2 

Moise Bertin Tchoula Tchokonte 1 *, Zwelithini Melford Mahlubi 1 , Paul De Villiers Du 

Plessis 2 , Andre Michael Strydom 2 and Dariuzs Kaczorowski 3 

1 Physics, University of the Western Cape, South Africa 

2 Physics, University of Johannesburg, South Africa 

3 Physics, Institute of Low Temperature and Structure Research, Polish Academy of 

Sciences., Poland 

The effects of substituting moment-bearing Tb in CePt 2Si 2 are reported through X-ray 

diffraction (XRD), electrical resistivity (ρ(T)), magnetic susceptibility (χ(T)) and 

magnetization (σ(μ0H)) measurements. XRD results for all compositions of the (Ce 1xTb 

x)Pt 2Si 2 system indicate a tetragonal CaBe 2Ge 2-type structure with space group P4/ 

nmm. ρ(T) results indicate the evolution from a coherent Kondo lattice to incoherent 

single-ion Kondo behavior up to 90% Ce substitution. χ(T) data at higher temperatures 

follow the Curie-Weiss relation for all alloy compositions and given effective moment 

values μeff which increase gradually from the expected value of 2.54 μB for the Ce 3+ 

-ion to the expected value of 9.72 μB for the Tb 3+ -ion. At low temperature χ(T) data 

exhibit antiferromagnetism in the concentration range 0.7≤ x ≤ 1. No evidence of 

metamagnetic behavior was observed from σ(μ0H) data for all compositions. 


Poster Thursday



RD24 

Heavy Fermion Behavior of Yb 2Ni 12P 7 Studied by 31P NMR 

Takehide Koyama 1 , Kyohei Sugiura 1 , Koichi Ueda 1 , Takeshi Mito 1 , Takao Kohara 1 , 

Tomohito Nakano 2 , Ryohei Satoh 3 , Katsuhiko Tsuchiya 3 and Naoya Takeda 2 


2 Faculty of Engineering, Niigata University, Japan 


We present results of the nuclear magnetic resonance measurement (NMR) of Ybbased 

intermetallic compound Yb 2Ni 12P 7, which crystallizes in the hexagonal Zr 2Fe 12P 7type 

structure [1]. Yb 2Ni 12P 7 does not order magnetically down to 50 mK and forms the 

heavy fermion state. The electronic specific heat of Yb 2Ni 12P 7 is markedly enhanced at 

low temperatures (200 mJ/K2 mol-Yb). The magnetic susceptibility shows the Curie- 

Weiss like behavior at high temperatures and has a noticeable hump at around 50 K. 

We have performed NMR measurement to investigate the electronic properties of 

Yb 2Ni 12P 7. The observed NMR line shows a complicated shape, reflecting the presence 

of three non-equivalent P sites and local symmetries around them. The nuclear-spin 

lattice relaxation rate (1/T1) shows nearly T1T=const. behavior, which is consistent 

with the delocalization of the 4f electrons. 

K. Zeppenfeld and W. Jeitschko, J. Phys. Chem. Solids, 54 (1993) 1527. 

RD25 

Electronic structure of RCu2Si2 (R=Yb, Y) studied by soft x-ray angleresolved 

photoemission spectroscopy 

Akira Yasui 1 , Shin-ichi Fujimori 1 , Ikuto Kawasaki 2 , Tetsuo Okane 1 , Yukiharu 

Takeda 1 , Yuji Saitoh 1 , Hiroshi Yamagami 3 , Akira Sekiyama 4 , Rikio Settai 5 , Tatsuma D 

Matsuda 6 , Yoshinori Haga 6 and Yoshichika Onuki 5 

1 

Condensed Matter Science Division, Japan Atomic Energy Agency, Japan 

2 

Advanced Meson Science Laboratory, RIKEN Nishina Center for Accelerator-Based Science, Japan 

3 

Department of Physics, Kyoto Sangyo University, Japan 

4 

Division of Materials Physics, Osaka University, Japan 

5 

Department of Physics, Osaka University, Japan 

6 

Advanced Science Research Center, Japan Atomic Energy Agency, Japan 

In recent years, electronic structure of YbCu 2Si 2, which is a classical example of Yb-based valence fluctuation 

compounds, has been studied by various experimental methods such as a quantum oscillation measurement 

[1] and an angle-integrated photoemission spectroscopy (AIPES) [2]. However, these results are inconsistent 

each other. In fact, the band structure calculation which well describes the results of the quantum oscillation 

measurement [1] cannot explain the AIPES spectrum. In the present study, we have performed the soft x-ray 

angle-resolved photoemission spectroscopy (SX-ARPES) for YbCu 2Si 2 to understand the valence band 

structure and the Fermi surface (FS) in a unified way. The SX-ARPES measurements were recorded in 

BL23SU of SPring-8. We have observed that hybridized bands of Yb 4f electrons and conduction states cross 

the Fermi level at 20 K, which is well below the Kondo temperature of TK = 50 K, in line with the valencefluctuating 

state of YbCu 2Si 2. We will discuss effects of Yb 4f electrons on its band structure by comparing 

the ARPES spectra with those of a non-4f reference compound YCu 2Si 2. 

[1] N. D. Dung et al., J. Phys. Soc. Jpn. 78, 084711 (2009). [2] M. Matsunami et al., Phys. Rev. B 78, 195118 (2008). 

RD26 

Anomalous increase of TC in UGa 2 under pressure 

Ladislav Havela 1 , A. Kolomiets 2 , J. Prchal 1 and A. V. Andreev 3 



3 Institute of Physics, Academy of Sciences of the Czech Pepublic, Czech Republic 

UGa 2 belongs to compounds quite thoroughly studied, although there is still no 

consensus about the character of the 5f states. In particular, 5f 2 or 5f 3 localized and 

band-like 5f states were considered, none of those being able to explain all its features 

[1]. Response of magnetic properties to external pressure is an important indicator of 

the situation of the 5f states. While band systems tend to a suppression of magnetic 

moments and their ordering, magnetism based on localized states has insensitive size 

of moments and their ordering temperatures can weakly increase. Previous experiments 

[2] indicated a quite rapid increase (approx. 3 K/GPa) of the Curie temperature from 

TC = 126 K up to p = 0.8 GPa. New resistivity experiments on UGa 2 single crystal, 

extending the pressure range up to 8 GPa, reveal a continuous linear increase, reaching 

160 K without any sign of saturation. Such anomalously large increase can be only 

understood in the framework of a two-band model, in which the compression leads to a 

stronger hybridization of the 5f and other conduction-electron states. 

[1] T. Honma et al., J. Phys. Soc. Japan 69 (2000) 2647. [2] A.V. Kolomiets et al., Physica B 259- 

261 (1999) 238. 


RE01 

Engineered p-d exchange interaction of coupled double diluted 

magnetic quantum dots 

Eun-young Kim 

Seoul National University, Korea 

This paper presents the effects of inserting a thick InGaN layer which was grown 

between n-GaN and active layer by MOCVD. By adding the thick InGaN layer, we 

expected the compensation of lattice mismatch between n-GaN and active layer. From 

AFM results, QDs (Quantum Dots) were formed at around 200 A InGaN thickness 

by TD (Threading Dislocation) termination effect. According to the result of TD 

termination, the electrical and optical properties were improved due to the decrease 

of non-radiative recombination area in active layer. The result of PL data shows PL 

intensity increased by inserting the thick InGaN layer. 

RE02 

Quasi-particle localization by disorder in an incompressible fractional 

quantum Hall state 

Partha Goswami* 

Physics department, D.B.College(University of Delhi),New Delhi, India, India 

The strongly correlated electrons, together with disorder, organize themselves in a nontrivial 

way to form incompressible collective states for the filling fraction ν = 5/2 in 

a dirty bi-layer semi-conductor quantum well system. The theoretical analysis of the 

quantum phase transition(QPT) exhibited by this system has been carried out including 

the single-particle quantum lifetime sensitive to the long range scattering and the usual 

zero field short-range Drude scattering (transport lifetime). Since the tunneling terms 

can be controlled by changing gate voltages, we find that, in principle, a completely 

reversible sequence of events, viz. a crossover from the bi-layer fractional quantum 

Hall state to the single-layer one followed by an entry to quantum critical state (and 

the QPT to the bi-layer state beyond) and eventually a crossover to the single-layer 

state, could be realized with the increase in inter-layer tunneling. The sequence, which 

is manifestation of quasi-particle localization by disorder, could prove to be useful in 

performing memory function and gating operation. 

RE03 

NpCoGe, near quantum criticality? 

Eric Colineau*, Rachel Eloirdi, Jean-christophe Griveau, Piotr Gaczynski and 

Alexander Shick 

European Commission, Joint Research Centre, Institute for Transuranium Elements, 

Germany 

The orthorhombic isostructural series AnTGe (An = actinide ; T = transition metal) 

offers a unique opportunity to study the properties and trends of a system where 

ferromagnetism and superconductivity coexist at ambient pressure in URhGe (TC = 

9.5K, TSC = 0.26K) [1] and UCoGe (TC = 3K, TSC = 0.7K) [2]. However, due to 

the difficulty to handle them, transuranium systems are much less documented. In an 

effort to bridge this gap, we have undertaken the study of the neptunium analogues 

and have previously reported that NpRhGe exhibits an antiferromagnetic ground 

state (TN = 21K, μNp = 1.14μB) [3]. In the present work, we have investigated 

NpCoGe by dc magnetization, ac susceptibility, specific heat, electrical resistivity, 

237Np Mossbauer spectroscopy and LSDA calculations. We find that NpCoGe orders 

antiferromagnetically at TN=13K with an average ordered moment = 0.8 μB. 

The weak antiferromagnetic interactions (θp = -5.5K) are overcome by the application 

of a moderate magnetic field (B ~ 3T) that induces a metamagnetic phase. NpCoGe 

appears as a more delocalized antiferromagnet than NpRhGe, which is consistent 

with the trend observed in UTGe analogues. The proximity of NpCoGe to a quantum 

critical point and its implications will be discussed.

RE04 

Pressure and magnetic-field induced non-Fermi-liquid behavior in 

YbCo 2Zn 20 

Kazuyuki Matsubayashi 1 *, Rina Yamanaka 1 , Yuta Saiga 2 , Tatsuya Kawae 3 and 

Yoshiya Uwatoko 1 


2 Institute for Advanced Materials Research, Hiroshima University, Japan 

3 Department of Applied Quantum Physics, Faculty of Engineering, Kyushu 


In heavy fermion systems, applying pressure and magnetic field controls the electronic 

configuration, and thus anomalous behaviors appear at around magnetic quantum critical point 

(QCP), such as an unconventional superconductivity and Non-Fermi-liquid behavior. Recently, 

YbCo 2Zn 20 have attracted much attention because of their heavy fermion state and proximity to 

the pressure-induced QCP [1]. It is worth noting that the critical pressure of YbCo 2Zn 20 is lower 

than that of other Yb based compounds. Therefore YbCo 2Zn 20 has an advantage of investigating 

the behavior of Yb- based compounds near QCP. More interestingly, it is reported that a 

metamagnetic crossover appears at H ~ 0.6 T [2], however, the origin of this metamagnetic 

behavior remains unclear. In order to shed light on the nature of the pressure- and field-induced 

quantum critical behavior, we have measured the specific heat of YbCo 2Zn 20 under pressure 

and magnetic field. We found that the low temperature specific heat in the vicinity of the critical 

region exhibits the power-law divergence. The temperature-pressure-magnetic field phase 

diagram will be presented to sum up the physical properties. 

[1] Y. Saiga et al., J. Phys. Soc. Jpn 77 (2008) 053710 [2] M. Ohya et al., J. Phys. Soc. Jpn 79 (2010) 083601 

RE05 

Relationship between single-particle excitation and spin excitation at 

the Mott transition 

Masanori Kohno* 

WPI Center for Materials Nanoarchitectonics, National Institute for Materials 

Science, Japan 

The Mott transition in the one- and two-dimensional Hubbard models is investigated 

using the Bethe ansatz, dynamical density-matrix renormalization group method, 

cluster perturbation theory, and random-phase approximation. I will show that the 

dispersion relation of single-particle excitation in a metallic phase leads continuously 

to that of spin excitation of the Mott insulator. 

RE06 

Quantum criticality in Kondo quantum dot coupled to 2D topological 

insulator 

Chung-hou Chung* and Salman Silotri 

Electrophysics Dept.,, National Chiao-Tung University, HsinChu, Taiwan, R.O.C., 

Taiwan 

We investigate theoretically the quantum phase transition between the one-channel 

Kondo (1CK) and two-channel Kondo (2CK) fixed points in a quantum dot coupled 

to edge states of interacting 2D topological insulators (2DTI) with Luttinger parameter 

0


RE10 


Magnetic phase diagram of UCoAl 

Tatsuma D. Matsuda 1 , Dai Aoki 2 , Naoyuki Tateiwa 1 , Etsuji Yamamoto 1 , Yoshinori 

Haga 1 , Yoshichika Onuki 3 , Jacques Flouquet 2 and Zachary Fisk 4 

1 

ASRC, JAEA, Japan 

2 

INAC/SPSMS, CEA-Grenoble, France 

3 


4 

University of California, USA 

Heavy fermion UCoAl is known to be a unique system with metamagnetic transition 

from paramagnetic to ferromagnetic ground states in uranium-based compounds. This 

kind of metamagnetism and quantum criticality in strongly correlated electron systems 

have attracted much attention because of expectation of new quantum phases. Recently, 

we succeeded to grow a high quality single crystal of UCoAl by the Czochralski 

pulling method and performed the magnetic measurements. In this presentation, we 

will show the magnetic phase diagram of UCoAl in detail. 

RE11 

Renormalization-group exponents for competitions between interelectronic 

and phonon-mediated interactions in ladder systems 

Wen-min Huang 1 *, Yiwei Cai 2 and Hsiu-hau Lin 2 

1 Physics Division, National Center for Theoretical Sciences, Taiwan 

2 Department of Physics, National Tsing Hua University, Taiwan 

After developing a scaling ansatz for electron-electron interactions under 

renormalization group transformation[1], we show that, with the inclusion of phononmediated 

interactions the ansatz, characterized by the divergent logarithmic length and 

a set of renormalization-group exponents, also works rather well. The superconducting 

phases in a doped two-leg ladder are studied and classified by these renormalizationgroup 

exponents as demonstration. Finally, nontrivial constraints among the exponents 

are derived and explained. 

[1] H.-Y. Shih, W.-M. Huang, S.-B. Hsu and H.-H. Lin, Phys. Rev. B 81, 121107(R) (2010). 

RE12 

Crystal Growth and Magnetic Order of Ni-doped CePdAl 

Veronika Fritsch 1 *, Sarah Woitschach 2 , Oliver Stockert 2 , Michael M. Koza 3 , Silvia 

Capelli 3 and Hilbert V. Loehneysen 4 

1 

Physikalisches Institut, Karlsruher Institut fuer Technologie, 76131 Karlsruhe, 

Germany 

2 

Max-Planck-Institut fuer Chemische Physik fester Stoffe, 01187 Dresden, Germany 

3 

Institut Laue-Langevin, 38042 Grenoble, France 

4 

Physikalisches Institut and Institut fuer Festkoerperphysik, Karlsruher Institut fuer 

Technologie, 76131 Karlsruhe, Germany 

CePdAl is a stoichiometric, antiferromagnetic compound (Neel temperature = 2.7 K) which 

can be tuned to a quantum critical point (QCP) by hydrostatic [T. Goto et al., J. Phys. Chem. of 

Solids 63, 1159 (2002)] or chemical pressure [Y. Isikawa et al., J. Phys. Soc. Jpn. 65, 117 (1996)]. 

The latter can be achieved by substituting Ni for Pd. Neutron-scattering experiments [A. Doenni 

et al., J. Phys.: Condens. Matter 8, 11213 (1996)] pointed towards a partial frustration of the Ce 

moments in CePdAl, making this system a promising candidate for investigating the influence 

of frustration on quantum criticality. We have grown large single crystals of Ni-doped CePdAl 

by the Czochralski method. The samples were characterized by x-ray powder diffraction, atomic 

absorption spectroscopy and x-ray Laue diffraction. Specific heat and inelastic neutron scattering 

data of CePdAl yield a Kondo temperature of approximately 5 K. Magnetization measurements 

display a strong magnetic anisotropy which is preserved in the Ni-doped compounds, where 

the magnetic order is suppressed. Neutron-diffraction experiments indicate that short-range 

correlations are present well above the Neel temperature. Below the Neel temperature, one third 

of the Ce moments display short-range order only, confirming the frustration in this system. 


RE13 

Transport properties of Ho 1-XLu XB 12 solid solutions 

Slavomir Gabani1*, Ivan Batko1, Marianna Batkova1, Karol Flachbart1, Emil Gazo1, 

Gabriel Pristas1, Iveta Takacova1, Alexey Bogach2, Nickolay Sluchanko2 and 

Natalya Shitsevalova 3 

1 Centre of Low Temperature Physics, Institute of Experimental Physics SAS, Slovak 

2 General Physics Institute RAS, Russia 

3 Institute for Problems of Materials Science NASU, Ukraine 

Recent studies of Ho 1-xLu xB 12 solid solutions have shown [1] that the antiferromagnetic 

(AF) order in geometrically frustrated system of HoB 12 (x = 0, TN = 7.4 K) is linearly 

suppressed to zero temperature, i.e. TN → 0, as lutetium concentration increases to 

x → xC 0.9. In this contribution, we present original results of electrical resistivity 

measurements on Ho 1-xLu xB 12 single crystalline samples with x = 0, 0.2, 0.5, 0.7, 0.9, 1 

in the temperature range 0.05 - 300 K and in magnetic fields (B) up to 8 T. Complex B 

vs TN phase diagrams were received from precise temperature and field dependences 

of resistivity with more AF phases for x ≥ 0.5 pointing to a possible quantum critical 

point at xC 0.9. The scattering of conduction electrons in the AF phase and in the 

paramagnetic phase as well as Hall effect results are analyzed and discussed for various 

concentrations x, when magnetic dilution increases with the increasing content of 

nonmagnetic Lu ions in the Ho 1-xLu xB 12 system. 

[1] S. Gabani, I. Batko, M. Batkova, K. Flachbart, E. Gazo, M. Reiffers, N. Shitsevalova, K. 

Siemensmeyer and N. Sluchanko, 17th <strong>International</strong> symposium on boron, borides and related 

materials, Sept 11-17, 2011, Istanbul, Turkey. 

RE14 

Low temperature thermal and electrical transport properties of ZrZn 2 

in high magnetic field 

Yang Zou 1 *, Michael Sutherland 1 , Stephen Hayden 2 and F. Malte Grosche 1 

1 Department of Physics, University of Cambridge, United Kingdom 

2 Department of Physics, University of Bristol, United Kingdom 

RE15 

WITHDRAWN 

Non fermi liquid behaviour in YFe 2Ge 2 

Yang Zou*, Zhuo Feng, Sven Friedemann and F. Malte Grosche 

Department of Physics, University of Cambridge, United Kingdom 

WITHDRAWN

RF01 

Magnetic orderings at the interface between Mott insulator and band 

insulator 

Suguru Ueda 1 *, Norio Kawakami 1 and Manfred Sigrist 2 


2 Theoretische Physik, ETH Zurich, Switzerland 

Recent experimental progress in crystal growth techniques enables us to investigate the complex oxide 

hetrostructures as a new frontier for studies of strongly correlated electron systems. In such systems, 

the main interest is put toward the metallic state around the interface, which is realized between 

two different insulating compounds, such as SrTiO 3/LaTiO 3 and SrTiO 3/LaAlO 3 [1]. Intriguingly, 

magnetism and superconductivity are also reported in such metallic interfaces [2]. Stimulated by these 

findings, we theoretically study the magnetic properties of the strongly correlated heterostructure 

composed a Mott insulator and band insulators. For this purpose, the single-band Hubbard model 

with long-range Coulomb interaction is investigated using the Hartree-Fock approximation [3]. We 

find the electronic and magnetic phases specific to the interface, including a canted anttiferromagnetic 

state and a charge-ordered state with checkerboard charge distribution. We elucidate the origin of 

these phases is closely related to the spatial inhomogeneity which induces unconventional couplings 

between spin and charge degrees of freedom. Additionally, the applied magnetic fields also reveal 

other aspects of correlated heterostructures; a first order metamagnetic transition and field-induced 

checkerboard charge-ordered state, which are also driven by the non-uniform charge distribution. 

[1] A. Ohtomo, et al., Nature 419, 378 (2002), A. Ohtomo, and H. Y. Hwang, Nature 427, 423 (2004). 

[2] A. Brinkman, et al., Nat. Mater. 6, 493 (2006), J. Biscaras, et al., Nat. Commun. 1, 89 (2010). [3] 

Okamoto, and Millis, Phys. Rev. B 70, 075101 (2004). 

RF02 

Strong Electron Correlation in Cu-doped CaO Nanocolloid 

Nguyen Thuy Trang 1 , Pham Thanh Cong 2 , Hoang Nam Nhat 3 * 

1 

Faculty of Physics, Vietnam National University, University of Natural Sciences, Viet 

Nam 

2 

Physikalisches Institut, Goethe-Universitat Frankfurt, Germany 

3 



Theoretical prediction of magnetism induced by defects or doping in non-metallic 

colloids has gained a renewed interests recently. In this work, we investigated the 

possible appearance of magnetism in Cu doped CaO nanocolloids activated by 

SPAN-80 in the framework of density functional theory (DFT). Despite of strong 

antiferromagnetic super-exchange interaction between Cu2+ ions, the local magnetic 

moment of Cu may appear due to colloidal agent attachment onto the surface of CaO 

nanocluster (surface modification). The ferromagnetism attributes to the degeneration 

of Cu 3d orbitals in CaO crystal fields, the aspects of electron correlation and quantum 

spin fluctuation. 

PACS number: 42.30.R, 42.40.Ht, 42.30.Kq 

Keywords: DFT, band-gap, CaO, calcium-oxide, mBJ, PBE, functional 

RF03 

The book-keeping fermion analysis of the double exchange model with 

antiferromagnetic background 

Kyohei Nakano 1 *, Robert Eder 2 , Yukinori Ohta 1 and Piotr Wrobel 3 


2 Institute for Solid State Physics, Karlsruhe Institute of Technology, Germany 

3 Institute for Low Temperature and Structure Research, Poland 

We analyse the double exchange model with antiferromagnetic background by the 

book-keeping fermion method. First, we consider the motion of a single conduction 

electron. We assume that the localized spins form the Neel state and the added 

conduction electron forms only three types of states under the strong Hund-coupling 

assumption and we regard these states as the book-keeping fermion. Under these 

assumptions, we calculate the spectral functions which show good agreement with the 

results given by the exact diagonalizations for finite size clusters. We also study the 

relation between the strength of the Hund coupling and the bandwidth in the lowerenergy 

region. The results show that the bandwidth approaches a finite value as the 

Hund-coupling constant becomes close to infinity. The bandwidth even increases with 

increasing the Hund coupling, which is in strong contrast to the expectation from the 

semi-classical theory. Next, we consider the situation where there are finite numbers of 

spin flips occurring in the down-spin sublattice in the Neel ordered state. Considering 

the effects of the spin defects, we add a new book-keeping fermion and estimate the 

energy of the spin defects by a perturbation theory. This theory gives the phase diagram 

comparable with the numerical results. 

RF04 

RF05 

RF06 


Phonon Induced Thermodynamic Properties of La 1-xCa xCoO 3 

Rasna Thakur*, Rajesh K. Thakur and N.k. Gaur 

Department of Physics, Barkatullah University, Bhopal, India 

Perovskite type cobaltate, La 1-xCaxCoO 3 (0 ≤ x ≤ 0.3) have been studied intensively 

because of their wide range of unique physical properties. The fact that rare-earth 

perovskite-type cobaltate are most suitable as a cathode material in solid oxide fuel 

cells (SOFC), makes the thermal behavior of these compounds highly important. As 

these compounds are predominantly ionic in nature hence the lattice contributions to 

the specific heat at constant volume (C v(lattice)) of pure and Ca doped LaCoO 3 has been 

studied and thereby thermal expansion is computed as function of temperature by 

means of Rigid Ion Model (RIM). We have systematically investigated the effect of 

phonons on thermal properties, Debye temperature (θ D), molecular force constant (f), 

Reststrahlen frequency (υ), cohesive energy (φ), and gruneisen parameter (γ) for La 1xCaxCoO 

3 (0 ≤ x ≤ 0.3). Also the effect of phonons on the bulk modulus is studied 

using the atoms in molecules (AIM) theory for pure and ca doped LaCoO 3. We have 

found that the computed properties reproduce well with the available experimental 

data, implying that RIM represents properly the perovskite cobaltate La 1-xCa xCoO 3 (0 

≤ x ≤ 0.3). To our knowledge some of the properties for these complicated compounds 

are reported for the first time. 

Dynamical antiferromagnetic phase transition after the quantum 

quench in the fermionic Hubbard model 

Naoto Tsuji* and Philipp Werner 

Institute for Theoretical Physics, ETH Zurich, Switzerland 

Spontaneous symmetry breaking is a universal concept in physics that stretches widely 

from condensed matter to cosmology. Recently it is getting feasible to study in detail 

how symmetry is dynamically broken in correlated electron systems using an ultrafast 

optical spectroscopy technique [1], which works as a key probe for electron correlation 

and fluctuations. Theoretically the phenomenon has been discussed with the Ginzburg- 

Landau (GL) theory, a macroscopic phenomenology. To capture the evolution of 

the electronic structure, however, one needs a microscopic description, which is not 

well understood. Here we take the fermionic Hubbard model, a typical microscopic 

model for correlated electrons, and study how the antiferromagnetic order develops 

from a paramagnetic initial state after the quantum quench using the nonequilibrium 

dynamical mean-field theory. The system shows a multistep time evolution: (i) a fast 

thermalization within the paramagnetic phase, (ii) an exponential growth of the order 

parameter, and (iii) decay of collective excitations. We show how these features are 

reflected in the single-particle and optical-conductivity spectrum, and discuss the 

nature of antiferromagnetic fluctuations. 

[1] R. Yusupov et al., Nat. Phys. 6, 681 (2010). 

Itinerant magnetism in the hubbard model within the dynamical 

cluster approximation 

Unjong Yu* 

GIST college, Gwangju Institute of Science and Technology, Korea 

There have been a lot of efforts to understand the itinerant magnetism because 

ferromagnetism in many metallic magnets like iron, cobalt, and nickel is due to the 

itinerant magnetism. However, the mechanism and the stability of the itinerant magnetism 

are not clear yet because the strong quantum mechanical correlation in time and space is 

crucial in the itinerant magnetism. The Stoner model, which is the most popular model for 

the itinerant magnetism, ignores those correlation effects and so is inadequate [1]. In this 

paper, we studied the itinerant magnetism within the dynamical mean-field theory (DMFT) 

and its cluster extension, dynamical cluster approximation (DCA). These two methods 

are non-perturbative and fully include strong correlation effects [2]. Particularly, the DCA 

incorporates spatial correlation (nonlocal effects) systematically and gives numerically 

exact solution for the many-body problem [3]. We applied these two methods to study the 

ferromagnetic and antiferromagnetic instability of the Hubbard model in the 2-dimensional 

square lattice, the 3-dimensional cubic lattice, and the face-centered-cubic (fcc) lattice. We 

show that the correlation in time and space reduces the critical temperature remarkably 

and is essential to understand the itinerant magnetism. 

[1] N. Majlis, The Quantum Theory of Magnetism, 2nd ed. (World Scientific Publishing, Singapore, 

2007), pp. 195-237. [2] D. Vollhardt et al., in Band-Ferromagnetism, edited by K. Baberschke et al. 

(Springer-Verlag, Berlin, 2001), p. 191. [3] U. Yu et al., Phys. Rev. Lett. 104, 037201 (2010). 


Poster Thursday


RF07 


First Principles DFT+U Method for Strongly Correlating Electronic 

Structure Systems 

Tomoyuki Hamada 1 , Takahisa Ohno 2 and Sadamichi Maekawa 3 

1 Central Research Laboratory, Hitachi Ltd., JST-CREST, Japan 

2 National Institute of Materials Research, Japan 

3 ASRC, JAEA, JST-CREST, Japan 

First principles density functional+U pseudopotential (DFT+U PP) method free 

from any empirical parameters has been developed and applied to the electronic 

structure calculations of strongly correlating electronic structure systems such as 

FeO and LaVO 3. The method can calculate the electronic structure of the systems 

from first principles, being contrary to the conventional DFT+U PP method, which 

uses empirical Ueff paramaters. The method primary calculates the Hubbard on-site 

interaction parameter Ueff for localized electrons, using an approximate constrained 

DFT technique, and then uses the calculated parameter in the DFT+U PP electronic 

structure calculation. Examples of calculations resulted in Ueff of Fe 3d electrons of 

anti-ferromagnetic FeO to be 5.11 eV (the empirical value is 5eV) and Ueffs of La 

4f and V 3d electrons of paramagnetic LaVO 3 to be 15.6 and 0.47 eV, respectively 

(the empirical values are 20.0 and 0 eV, respectively). The band gap structure of 

these materials was correctly described. Our method seems to be a promising tool 

for investigating strongly correlating electronic structure systems for spintronics 

applications, correctly describing the localized and itinerant nature of electrons of the 

systems from first principles. 

RF08 

Correlation effect in ferromagnetic 3d transition metals 

Muneyuki Nishishita 1 , Sudhakar Pandey 2 and Dai Hirashima 1 * 


2 APTPC, Korea 

RF09 

MOVED 

Mott transition in frustrated Hubbard model with spatial anisotropy: Cellular 

dynamical mean field study 

Tomoko Kita 1*, Yuta Furukawa 1, Takuma Ohashi 2 and Norio Kawakami 1 



Geometrical frustration has attracted much interest in the field of strongly correlated 

electron systems. In the frustrated systems, a lot of intriguing phenomena such as 

the heavy fermion behavior in LiV 2O 4, spin liquid ground state in organic materials, 

etc. have been observed and they have stimulated theoretical investigations of 

frustrated electron systems. In particular, the reentrant behavior in the Mott transition 

in moderately frustrated systems, the heavy Fermi-liquid behavior around the Mott 

transition, etc. are new aspects of the Mott transition and very interesting. In our recent 

study on the kagome lattice system with spatial anisotropy [1] and also Ref. [2], it has 

been found that the anisotropy is strongly enhanced around the Mott transition, which 

stabilizes antiferromagnetic spin configurations. In this study, we apply the cellular 

dynamical mean field theory combined with a continuous-time quantum Monte Carlo 

solver [3] to the Hubbard model on the anisotropic kagome and triangular lattices. 

We systematically investigate the effects of the enhanced anisotropy around the Mott 

transition on the quasiparticle spectra and spin correlation functions. 

[1] Y. Furukawa et al.: Phys. Rev. B 82 (2010) 161101. [2] A. Yamada et al.: Phys. Rev. B 83 (2011) 

195127. [3] G. Kotliar et al.: Phys. Rev. Lett. 87 (2001) 186401; P. Werner et al.: Phys. Rev. Lett. 97 

(2006) 076405. 


RF10 

Spin-nematic and -singlet states in the Mott insulator phase of the S=1 

two-dimensional Bose-Hubbard model 

Yuta Toga 1 , Hiroki Tsuchiura 1 , Makoto Yamashita 2 and Hisatoshi Yokoyama 3 


2 NTT Basic Research Laboratories, NTT Corporation, Japan 


Because of the recent development in experimental cold-atom physics, a quantum gas microscope technique 

has opened the door for detecting and manipulating single bosonic atoms at single site level in an optical 

lattice, just like scanning tunneling microscopy in solid-state physics. Quite recently, Endres et al [1]. used this 

technique to track the superfluid-Mott insulator (SF-MI) transition of spinless bosonic-atoms on an optical 

lattice in more detail, and found that correlated pairs of a doubly populated site and an unpopulated site which 

representing the excitations in the MI, fundamentally determine the properties of the SF-MI transition, which 

is consistent with recent numerical studies [2,3]. Theoretically, spin-1 bosonic atoms on a two-dimensional 

lattice is also of prime importance because it is a bosonic analogue of the two-dimensional fermionic (S=1/2) 

Hubbard model, which has been exhaustively studied in the context of magnetism and high-temperature 

superconductivity. Thus in this work, we study the ground state properties and quantum phase transitions of 

S=1 two-dimensional Bose-Hubbard model, focusing on correlated pairs excitations based on a variational 

Monte Carlo approach. We discuss the spin-structures in the MI, and present a consistent description of the 

transition from the spin-nematic state to the spin-singlet state beyond mean-field theory. 

[1]M. Endres, M. Cheneau, T. Fukuhara, C. Weitenberg, P. Schauß, C. Gross, L. Mazza, M. C. Banuls, L. Pollet, I. 

Bloch, and S. Kuhr, Science 334 (2011) 200. [2] M. Capello, F. Becca, M. Fabrizio, and S. Sorella, Phys. Rev. 

Lett. 99 (2007) 056402; Phys. Rev. B 77 (2008) 144517. [3] H. Yokoyama and M. Ogata, J. Phys. Chem. Solids 

69 (2008) 3356; H. Yokoyama, T. Miyagawa, and M. Ogata, J. Phys. Soc. Jpn 80 (2011) 084607. 

RF11 

Dynamical instability in two-component bosonic systems in an optical 

lattice 

Rui Asaoka 1 , Yuta Toga 1 , Hiroaki Tsuchiura 1 and Makoto Yamashita 2 

1 Depertment of Applied Physics, Tohoku University, Japan 

2 NTT Basic Research Laboratories, NTT Corporation, Japan 

Because of the recent development in experimental technique, there has been an emerging 

interest in dynamical properties of Bose-Einstein condensates (BEC) on an optical lattice. 

In particular, quantum gas microscope technique has opened the door for real-time 

observation of single bosonic atoms at single site level in an optical lattice, which can act 

as scanning tunneling microscopy in solid state physics. Quite recently, Greiner and his 

co-workers used this technique to track the superfluid-Mott insulator (SF-MI) transition 

of bosonic-atoms in real-space and time [1,2]. Further studies for dynamical properties 

of BEC may be only a matter in time. Dynamical analysis of BEC in strongly correlated 

bosonic systems is also of interest in theoretical point of view. In particular, the dynamical 

instability of SF in multi-component bosonic systems is of prime importance because 

there would be entangled interplay among superfluidity, Mott physics, and possibly also 

Anderson localization. Thus, in this work, we study the dynamical instability of the SF 

phase of the two-component Bose-Hubbard model based on the dynamical Gutzwiller 

approximation. We mainly focus on the effects of the dispersive current of one-component 

on the stability of SF current of another component. 

[1] W. S. Bakr et al., Science 329, 547 (2010). [2] M. Endres et al., Science 334, 200 (2011). 

RF12 

Mechanism for the high Neel temperature in SrTcO3 

Ashis Kumar Nandy 1 , S. Middey 1 , Priya Mahadevan 2 * and D. D. Sarma 3 

1 

Centre for Advanced Materials, Indian Association for the Cultivation of Science, 

India 

2 

S.N. Bose National Centre for Basic Sciences, India 

3 

Solid State and Structural Chemistry Unit, Indian Institute of Science, India 

The microscopic origin [1] of the high Neel temperature observed experimentally 

in SrTcO 3 [2] and CaTcO 3 [3] has been examined using a combination of ab-initio 

electronic structure calculations and mean-field solutions of a multi-band Hubbard 

model. The G-type anti-ferromagnetic state is found to be robust for a large region 

of parameter space, with large stabilization energies found, surprisingly, for small 

values of intra-atomic exchange interaction strength as well as large bandwidths. 

The microscopic origin of this is traced to specific aspects associated with the d3 

configuration at the transition-metal site. Considering values of interaction strengths 

appropriate for SrTcO 3 and the corresponding 3d oxide SrMnO 3, we find a ratio of 4:1 

for the Neel temperatures as well as magnitudes consistent with experiment. 

1. S. Middey, Ashis Kumar Nandy, Priya Mahadevan, D.D. Sarma, arXiv:1112.5587 2. E. E. 

Rodriguez et. al., Phys. Rev. Lett. 106, 067201 (2011). 3. M. Avdeev et. al., J. Am. Chem. Soc. 133, 

1654 (2011).

RF13 

Spin-spectral-weight distribution and energy range of the parent 

compound La 2CuO 4 

Jose Carmelo 1 , Miguel Araujo 2 , Steven White 3 and Maria Sampaio 1 

1 Departament of Physics, University of Minho, Portugal 

2 Departament of Physics, University of Evora, Portugal 

3 Departament of Physics, University of California, USA 

The spectral-weight distribution in recent neutron scattering experiments on the parent 

compound La 2CuO 4 (LCO) [1], which are limited in energy range to about 450 meV, 

is studied in the framework of the Hubbard model on the square lattice [2]. We find 

that the higher-energy weight extends to about 566 meV and is located at and near 

the momentum [pi,pi]. Our results confirm that the U/t value suitable to LCO is in the 

range between U/t=6 and U/t=8. The continuum weight energy-integrated intensity 

vanishes or is extremely small at momentum [pi,0]. This behavior of the intensity is 

consistent with that of spin waves, which are damped at [pi,0]. Our study combines 

a number of theoretical and numerical approaches, including, in addition to standard 

treatments [3], a new spinon approach for the spin excitations [4,5] and density matrix 

renormalization group (DMRG) calculations for Hubbard cylinders [6]. 

[1] - N. S. Headings, S. M. Hayden, R. Coldea, and T. G. Perring, Phys. Rev. Lett. 105, 247001 (2010). 

[2] - M. A. N. Araujo, J. M. P. Carmelo, M. J. Sampaio, and S. R. White, cond-mat.str-el.1201.5940. 

[3] - N. M . Peres and M. A. N. Araujo, Phys. Rev. B 65, 132404 (2002). [4] - J. M. P. Carmelo, 

Nucl. Phys. B 824, 452 (2010); Nucl. Phys. B 840, 553 (2010), Erratum. [5] - J. M. P. Carmelo, 

Ann. Phys. 327, 553 (2012). [6] - S. Yan, D. A. Huse, and S. R. White, Science 332, 1173 (2011). 

RF14 

J 1J 2 anti-ferromagnetic heisenberg model on bilayer honeycomb lattice 

Mojtaba Shoja Shabankah and Farhad Shahbazi 

Physics, Isfahan University Of Technology, Iran 

Recent experiment on spin-3/2 bilayer honeycomb lattice antiferromagnet Bi 3 Mn 4 

O 12 (NO 3) shows a spin liquid behavior down to very low temperatures. This behavior 

can be ascribed to the frustration effect due to competitions between first and second 

nearest neighbor antiferromagnet interaction. Motivated by the experiment, we study 

J 1J 2Antiferromagnet Heisenberg model, using Mean field theory and Monte Carlo 

simulation. This calculation shows highly degenerate ground state. We also calculate 

the effect of second nearest neighbor through z direction and show these neighbors 

also increase frustration in these systems. In addition calculation of the effect of third 

nearest neighbor shows that this interaction can lift the degenerate ground state to four 

discrete states. The next step of these calculations is to consider quantum effect of these 

interactions by Word line quantum Monte Carlo method. 

[1] S. Okumura, H. Kawamura, T. Okubo, Y. Motome J. Phys. Soc. Jpn. 79, 114705 (2010) [2] J. 

N. Reimers, A. J. Berlinsky, and A.-C. Shi , Phys. Rev. B 43, 865-878 (1991) [3] Hem C. Kandpal 

and Jeroen van den Brink, PHYSICAL REVIEW B 83, 140412(R) (2011) [4] M Azuma, M Matsuda, 

N Onishi, S Olga, Y Kusano, M Tokunaga, Y Shimakawa and N Kumada, Journal of Physics: 

<strong>Conference</strong> Series 320 (2011) 012005. [5] L. Balents, Nature (London) 464, 199 (2010). 

RF15 

A hybrid exchange density functional study of La 1-xCa xMnO 3 

Romi Kaur Korotana 1 , Leandro Liborio 1 , Giuseppe Mallia 1 , Zsolt Gercsi 2 and 

Nicholas Harrison 1 

1 Chemistry, Imperial College London, United Kingdom 

2 Physics, Imperial College London, United Kingdom 

Manganites exhibit a rich variety of crytallographic, electronic and magnetic properties 

[1] manifested in ferromagnetic-, antiferromagnetic (collinear and canted)-, metallic-, 

insulating-,charge- and orbital-ordered states. An insight into the competition and coupling 

between various degrees of freedom in doped manganites is of interest for the optimisation 

of the magnetocaloric effect [2, 3] in such materials. In this work, hybrid-exchange density 

functional theory (DFT) calculations have been carried out to determine the effects of A-site 

doping on the structural, electronic and magnetic properties of perovskite-type manganites 

La 1-x A x MnO 3 , where A=Ca and x=0, 0.25, 0.50, 0.75 and 1. A magnetic stability plot for 

La 1-x Ca x MnO 3 is complied, in which the ferromagnetic (F), antiferromagnetic A-type (A-AF), 

G-type (G-AF) and C-type (C-AF) configurations are considered. At this level of theory, the 

structural, magnetic ground states and electronic states at each of the compositions studied 

are compared to available experimental data. This provides a basis for a first principles 

description of the magnetocaloric effect in La 1-x Ca x MnO 3 systems. 

[1] J. B. Goodenough, in Handbook on the Physics and Chemistry of Rare Earths, vol 33, edited by K. A. 

Gschneidner, Jr. et al. (Elsevier 2003), p. 249. Elsevier, Amsterdam (2003). [2] V. K. Pecharsky and K. A. 

Gschneidner, Jr., J. Magn. Magn. Mater., 200, 44 (2002). [3] A. M. Tishin, in Handbook of Magnetic 

Materials, edited by K. H. J. Buschow (North Holland, Amsterdam, 1999), Vol. 12, pp. 395-524. 

RF16 

RG01 


Magnetic properties of GdFe 11Ti via first principal calculations. 

E. E. Kokorina*, M. V. Medvedev and I. A. Nekrasov 

Laboratory of Theoretical Physics, Institute of Electrophysics, Russia 

RF17 

WITHDRAWN 

Mott transition of ultracold Fermi-Fermi mixtures in optical lattices 

Takahiro Ooi* and Seiichiro Suga 

University of Hyogo, Japan 

WITHDRAWN 

Anisotropy in a high Landau level due to effective electron-electron 

interactions 

Orion Ciftja 

Prairie View A&M University, USA 

Quantization of Hall resistivity in strongly correlated two-dimensional electronic 

systems at high magnetic fields generally indicates the stabilization of novel electronic 

quantum liquid phases of matter. This is the nature of the integer and fractional 

quantum Hall states that stabilize at integer and fractional odd-denominator (not 

always, though) filling factors of the Landau level. Away from certain filling factors 

that represent quantum Hall liquid states, different phases, some of them with 

unusually high magneto-transport anisotropy have been known to stabilize specially in 

high Landau levels. In this work, we try to understand the anisotropy of such quantum 

phases in terms of effective electron-electron interaction potentials. To this effect, we 

implement a full projection of the original Coulomb interaction potential in the suitable 

Landau level. We find out that, in high Landau levels, thus for relatively weak magnetic 

fields, a semi-classical description of the interaction potential between electrons appear 

to be an adequate choice. The features of this semi-classical interaction potential in 

this limit suggest ways how the energetic balance between density waves and/or liquid 

crystalline phases might be sensitively affected. 

[1] R. B. Laughlin, Phys. Rev. Lett. 50, 1395 (1983). [2] P. K. Lam and S. M. Girvin, Phys. Rev. B. 

30, R473 (1984). [3] O. Ciftja and C. Wexler, Phys. Rev. B 67, 075304 (2003). 


Poster Thursday



RG02 

Bipolaron-Bipolaron interaction in many electron Holstein-Hubbard 

model 

Monodeep Chakraborty and B. I. Min 


Polarons and bipolarons have been long-term subjects of interest in many areas 

of condensed matter. The Holstein model describing the strong electron-phonon 

interaction and the Hubbard model describing the strong electron-electron interaction 

have played pivotal roles in various important physical systems, such as high Tc 

superconductors and the CMR manganites. In real systems, the polaron-polaron and 

polaron-bipolaron interactions might be of crucial importance. In order to investigate 

the physics of polaron and bipolaron systematically, we have studied the combined 

Holstein-Hubbard model treating both the electron-phonon and the electron-electron 

interaction on an equal footing. We present our study on polaron-bipolaron and 

bipolaron-bipolaron interactions as a function of the electron-phonon coupling strength 

and the electron-electron interaction U . We have calculated the ground state energy 

and wave functions of the system by applying the conjugate-gradient technique on 

a variationally constructed basis. The obtained correlation functions, the bipolaron 

binding energy, and the effective mass enables us to capture the intricate mechanisms 

at play and their consequences. 

RG03 

Partial disorder in an Ising-spin Kondo lattice model on a triangular 

lattice 

Hiroaki Ishizuka* and Yukitoshi Motome 

Department of Applied Physics, University of Tokyo, Japan 

Partial disorder, that is coexistence of paramagnetic and magnetically ordered sites, 

is an intriguing example of exotic orders induced by geometrical frustration [1]. 

Experimentally, several metallic magnets with a triangular lattice structure, such as 

UNi 4B and Ag 2CrO 2, were reported to present such unique order. On the other hand, 

theoretical attempts to explore the partial disorder in two-dimensional localized spin 

systems turned out to be unsuccessful so far; it is fragile against thermal fluctuations 

[2] and only exists as a quasi-long-range order at most [3]. To explore the possible 

realization of the true long-range partially disordered phase in two dimensions, here 

we theoretically investigate the effect of the coupling of localized moments to itinerant 

electrons in an Ising-spin Kondo lattice model on a triangular lattice. We study the 

low-temperature magnetic phases by a real-space Monte Carlo technique. As a result, 

we obtained a long-range order of the partially disordered state at finite temperatures 

in the vicinity of electron density n=1/3, where a two-sublattice stripe-type order and 

three-sublattice ferrimagnetic order compete with each other and an electronic phase 

separation takes place at a lower temperature. Further details on the phase diagram and 

the partially disordered phase will be given in the presentation. 

[1] M. Mekata, J. Phys. Soc. Jpn. 42, 76 (1977). [2] S. Fujiki et al., J. Phys. Soc. Jpn. 53, 1371 (1984). 

[3] T. Takagi and M. Mekata, J. Phys. Soc. Jpn. 64, 4609 (1995). 

RG04 

Basis reduction in the exact diagonalization method for the dynamical 

mean-field theory 

Hyeong-do Kim* 

Beamline Division, Pohang Accelerator Laboratory, Korea 

The exact diagonalization (ED) method for the dynamical mean-field theory is nearly 

the only method to calculate electron spectra involving core levels, such as core-level 

photoemission spectra, x-ray absorption/emission spectra, resonant inelastic x-ray 

scattering, etc., in a strongly correlated electron systems. In order to overcome the 

problem of the exponentially increasing Hilbert-space dimension by the number of 

sites, the number of configurational bases for the ED method for the single-impurity 

Anderson model is systematically reduced by their perturbative expansion starting 

from the lowest-energy configuration and consecutively allowing the hopping between 

an impurity level and a conduction band. Comparison of resulting Green's functions 

with exact ones in an imaginary frequency axis shows that bases up to the fourth 

order is enough to render reliable results. Since the reduced Hilbert-space dimension 

increases according to the power law, the available size of involved sites could be 

greatly enhanced to simulate core-level-related spectra with a large spin-orbital degree 

of freedom. 


RG05 

Electronic Structure of ternary stannides RRu4Sn6 (R=Y, La, Pr, Ce, 

and Gd) compounds 

Saad Elgazar 1, A. M. Strydom 1 and P. M. Oppeneer 2 

1 Physics, Johannesburg University, South Africa 

2 Physics, Uppsala University, Sweden 

We report density functional calculations of the band structure and density of states 

of the RRu4Sn6 (M=Y, La, Ce, and Gd) compounds. Our investigation is carried 

out within the framework of the local density approximation, using a relativistic, 

full-potential band-structure method. For the Ce-146 compound we find that LSDA 

calculations predict a semiconducting ordered ground state whereas the other 

compounds ordered in metallic states, in accordance with available experimental 

measurements 

RG06 

Local correlation effects in Mn doped GaAs 

Igor Di Marco*, Olle Eriksson and Patrik Thunstrom 

Physics and Astronomy - Materials Theory, Uppsala University, Sweden 

RG07 

WITHDRAWN 

First-principles study on noncollinear magnetism and effects of spinorbit 

coupling in 5d pyrochlore oxide Cd 2Os 2O 7 

Hiroshi Shinaoka, Takashi Miyake and Shoji Ishibashi 

Nanosystem Research Institute, National Institute of Advanced Industrial Science and 


Recently, increasing attention has been focused on 5d pyrochlore oxides A 2B 2O 7 (B=Ir, Os, etc.) in search 

for unconventional phenomena induced by strong spin-orbit coupling. Cd 2Os 2O 7 is a typical member of 

these compounds. Experimentally, it exhibits a metal-insulator transition at 227 K, below which a Neel order 

appears [1]. Despite many experimental attempts, the nature of the low-temperature phase remains to be 

clarified; e.g., the magnetic structure is unknown. Furthermore, several peculiar properties have been reported 

experimentally: (1) The transition temperature is the highest among pyrochlore oxides. (2) No clear charge 

gap is seen in the temperature dependence of the resistivity despite the high transition temperature. Motivated 

by these experiments, we investigate electronic structure of Cd 2Os 2O 7 [2] using the local spin density 

approximation + U method. We use a fully relativistic two-component first-principles computational code 

[3] based on the projector augmented-wave method. We show that the so-called all-in/all-out magnetic order 

is the most stable in a wide range of U. By analyzing an effective spin model, we show that the local 

easy-axis anisotropy removes geometrical frustration to stabilize this non-collinear magnetic order. We also 

compute the density of states and the electronic band structure and compare the results with experiments. 

[1] A. Sleight et al., Solid State Comm. 14, 357 (1974); D. Mandrus et al., Phys. Rev. B 63, 195104 

(2001); A. Koda et al., J. Phys. Soc. Jpn. 76, 063703 (2007); Y. H. Matsuda et al., Phys. Rev. B 84, 

174431 (2011). [2] H. Shinaoka, T. Miyake, and S. Ishibashi, arXiv:1111.6347. [3] QMAS (Quantum 

MAterials Simulator) [http://qmas.jp/].

RG08 

Nonequilibrium states and I-V characteristics in one-dimensional band 

and Mott insulators attached to electrodes 

Yasuhiro Tanaka* and Kenji Yonemitsu 

Institute for Molecular Science, Japan 

Nonequilibrium states induced by an applied bias voltage (V) and the corresponding 

current-voltage characteristics of one-dimensional models describing band and Mott 

insulators are investigated theoretically by using nonequilibrium Green's functions[1]. 

We attach the models to metallic electrodes whose effects are incorporated into the 

self-energy. Modulation of the electron density and the scalar potential coming from 

the additional long-range interaction are calculated self-consistently within the Hartree 

approximation. For both models of band and Mott insulators with length L_C, the bias 

voltage induces a breakdown of the insulating state, whose threshold shows a crossover 

depending on L_C[2]. It is determined basically by the bias V_{th}~Δ for L_C smaller 

than the correlation length ξ=W/Δ where W denotes the bandwidth and Δ the energy 

gap. For systems with L_C ξ, the threshold is governed by the electric field, V_{th}/ 

L_C, which is consistent with a Landau-Zener-type breakdown, V_{th}/L_C Δ^2/ 

W. We demonstrate that the spatial dependence of the scalar potential is crucially 

important for this crossover by showing the case without the scalar potential, where the 

breakdown occurs at V_{th} Δ regardless of the length L_C. 

[1] K. Yonemitsu, J. Phys. Soc. Jpn. 78 (2009) 054705. [2] Y. Tanaka and K. Yonemitsu, Phys. Rev. 

B 83 (2011) 085113. 

RG09 

Enhancement of charge ordering by Zeeman effect in one-dimensional 

molecular conductors 

Hideo Yoshioka 1 , Hitoshi Seo 2 and Yuichi Otsuka 3 

1 Department of Physics, Nara Women's University, Japan 

2 Condensed Matter Theory Laboratory, RIKEN, Japan 

3 Advanced Institute for Computational Science, RIKEN, Japan 

A recent experiment observes increase of resistance with increasing the external 

magnetic field in one-dimensional molecular conductor TPP[Co(Pc)(CN)_2]_2 [1]. The 

positive magnetoresistance is independent of the direction of the magnetic field, and 

then the origin of it is considered to be the Zeeman effect. Therefore, the experiment 

indicates that charge ordering (CO) is enhanced by the Zeeman effect. Stimulated by 

the experiment, we theoretically investigate effect of uniform magnetic field on CO 

in one-dimensional extended Hubbard model. In a previous study, the ground state 

with coexistence of CO and 2k_F-SDW was investigated, but the amplitude of CO 

does not show noticeable enhancement under the uniform magnetic field [2]. In the 

present study, the parameter region where only CO appears is studied. We find the 

following results; (1) The amplitude of CO shows continuous enhancement under the 

external magnetic field. (2) Enhancement of CO is accompanied by both uniform and 

staggered (4 k_F) component of magnetic moment. Our conclusion is consistent with 

experimental finding in TPP[Co(Pc)(CN)_2]_2. 

[1] N. Hanasaki et al., J. Phys. Soc. Jpn. 75 (2006) 104743. [2] K. Kishigi and Y. Hasegawa, J. 

Phys. Soc. Jpn. 69 (2000) 2145. 

RG10 

Contribution of electron-lattice and spin-orbit coupling to the 

insulator-metal transition in VO2 and Sr2IrO4 Jongseok Lee 1 , K. Shibuya 2 , Y. Krockenberger 2 , K. S. Takahashi 2 , M. Kawasaki 3 and Y. 

Tokura 3 

1 

Department of Photonic and Applied Physics, Gwangju Institute of Science and 


2 

Cross-Correlated Materials Research Group (CMRG) and Correlated Electron 

Research Group (CERG), RIKEN, Japan 

3 

Department of Applied Physics, University of Tokyo, Japan 

Mott insulating state in the strongly correlated electron system is often realized in 

competition and/or cooperation with interactions other than the on-site Coulomb 

repulsion energy, such as the electron-lattice coupling and the spin-orbit coupling 

One of representative examples is VO 2 where the electron correlation and the Peierls 

instability have been debated as a driving force to realize its metal-insulator transition 

near room temperature. Another example is Sr 2IrO 4 which is now believed to have a 

spin-orbit-induced Mott insulator ground state. In this presentation, we discuss based 

on optical spectroscopy of thin films how the insulating ground states of each system 

evolve into the metallic states with a decrease of Peierls instability and the spin-orbit 

coupling strength which together can give an insight in to the complex phases in 

strongly correlated electron system [1,2]. 

[1] J. S. Lee, Y. Krockenberg, K. Takahashi, M. Kawasaki, and Y. Tokura, Phys. Rev. B 85, 035101 

(2012). [2] J. S. Lee, K. Shibuya, M. Kawasaki, and Y. Tokura, submitted. 

RG11 

RG12 

RG13 


Multipole moments at Pr-site and electric field gradients at Sb-site in 

PrOs_4Sb_12_ 

Takeshi Goho* and Hisatomo Harima 

Department of Physics, Kobe University , Nada , Kobe 657-8501, Japan 

PrOs_4Sb_12_ is well known as an unusual superconductor with Tc = 1.85 K [1]. 

The superconductivity might be related with the multipole moments of 4f^2 electrons 

of Pr, because the antiferro-quadrupole ordering is realized under applied magnetic 

fields [2]. So, it is important to study a role of the multipole moments of Pr to make 

clear the system of unusual superconductor PrOs_4Sb_12_. The NQR frequency at 

Sb site shows temperature dependence corresponding to the crystalline electric field 

splitting below 10 K, associated with the Pr^3+^(4f^2)-derived ground state [3]. 

This experimental result suggests that the change of multipole components affect the 

electronic field gradients (EFG) at Sb-site. The LDA + U calculations have described 

the Fermi surfaces of PrOs_4Sb_12_ well [4]. It has been shown that EFG at Sb-site 

can be calculated by using an FLAPW method and the calculated EFG reproduce well 

the experimental NQR frequency [5]. Moreover, the multipole moments of Pr can be 

classified from the density matrix, which is used in the LDA + U method. we have 

analyzed how each multipole component affects the EFG at Sb-site. Then we discuss 

the relationship between multipole moments at Pr-site and EFG at Sb-site. 

[1] E. D. Bauer et al., Phys. Rev. B 65 (2002) 100506. [2] M. Kohgi et al., J. Phys. Soc. Jpn. 72 (2003) 

1002. [3] M. Yogi et al., Phys. Rev. B 67 (2003) 180501(R). [4] H. Sugawara et al., Phys. Rev. B 66 

(2002) 220504(R). [5] H. Harima, Physica B 378-380 (2006) 246. 

The effect of pairing fluctuations and disorder on the BCS-BEC 

crossover 

Pinaki Majumdar 

Harish-Chandra Research Institute, India 

A fermi liquid with weak attractive interaction undergoes a BCS transition to a 

superconductor with reducing temperature. With increasing interaction strength the 

transition temperature displays non-monotonic behaviour as the system heads towards 

Bose condensation of preformed pairs. We use a new Monte Carlo tool, incorporating 

amplitude and phase fluctuations of the pairing field, to map out this BCS-BEC 

crossover in the attractive Hubbard model on large (40 X 40) two dimensional lattices. 

Havingestablished this benchmark we discuss the role of disorder in this system. This 

includes (i) the role of non-magnetic impurities where we track the superconductor 

to insulator transition with increasing disorder, and (ii) the emergence of `gapless' 

superconductivity, the suppression of T_c, and the induced correlation between 

scatterers themselves, in the case of magnetic impurities. Our method reproduces the 

standard results in all these cases but allows unprecedented spatial resolution, and 

access to the dynamical response. We compare the results to imaging experiments on 

disordered films. 

Transport properties of ferromagnetic material with Anderson- 

Hubbard centers 

Yuriy Skorenkyy*, Oleksandr Kramar and Leonid Didukh 

Physics Department, Ternopil National Technical University, Ukraine 

A competition between itinerant behavior and localization effects in strongly 

correlated electron system of periodically spaced Anderson-Hubbard centers 

introduced into narrow-band metal is studied. The configurational representation for 

localized subsystem is used and the effective Hamiltonian is obtained by canonical 

transformation. Besides the spin-spin interactions and strong on-site Coulomb 

interaction, the model takes into account the hybridization with conduction band which 

results in the indirect hopping and indirect exchange interactions. Lattice deformation 

under the external pressure is taken into account and equilibrium value of lattice 

strain is found, having effect on both electrical and magnetic properties of the system. 

Green functions for band and localized electrons are calculated. On this base, the 

energy spectrum and magnetization are investigated as function of model parameters, 

temperature and external pressure. For temperatures close to Curie temperature and 

partial filling of conduction band the peculiarities of electronic conductivity are studied. 

Concentration dependence of static conductivity exhibits different transport regimes. 

Our results show that in the considered model the effects of localization are enhanced 

even if external pressure promotes electrical conductivity. 


Poster Thursday



RG14 

First principles studies of organic charge transfer salts 

Harald O. Jeschke, Anthony Jacko and Roser Valenti 

Institut fur Theoretische Physik, Universitat Frankfurt, Germany 

We study a number of BEDT-TTF based charge transfer salts in the framework of ab 

initio density functional theory and determine the parameters of the effective Hubbard 

Hamiltonian describing the low energy excitations[1]. For the spin liquid candidate 

kappa-(BEDT-TTF)2Cu 2(CN) 3, we investigate the question if the structures determined 

at various temperatures lead to different effective Hamiltonian representations[2]. For 

the Fabre salts (TMTTF)2X, we compare the properties of the underlying Hamiltonian 

for a series of different anions X. 

[1] H.C. Kandpal, I. Opahle, Y.-Z. Zhang, H. O. Jeschke, R. Valenti, Phys. Rev. Lett. 103, 067007 

(2009). [2] H. O. Jeschke, M. de Souza, R. Valenti, R. S. Manna, M. Lang, J. A. Schlueter, Phys. Rev. 

B 85, 035125 (2012) 

RG15 

Dynamics of strongly correlated Fermi systems: The efffects of pairexcitations 

and exchange 

Martin Panholzer 1 *, Eckhard Krotscheck 2 , Helga M Boehm 2 , Robert Holler 2 and 

Thomas Lichtenegger 2 

1 Johannes Kepler University Linz, Austria 

2 Institut for Theoretical Physics, Johannes Kepler University Linz, Austria 

Understanding the emergent properties of many body systems from the underlying microscopic 

interactions is the major goal of condensed matter physics. Recent progress, in the understanding 

of the dynamics of strongly correlated systems, has been made by approximating the excited 

wave function by a superposition of correlated particle-hole and 2-particle-2-hole excitations. 

The amplitudes, describing these excitations, are obtained by minimizing the action integral. A 

surprising result of this approach is the confirmation/prediction of the reemergence of collective 

mode below the PHB in two dimensional 3He for density fluctuations. By including exchange the 

agreement of the calculated spectrum with the experiment was further improved for 3He. The next 

step is to apply this tool to spin-density fluctuations, which are of inherent exchange character. Due 

to the proximity of the ferromagnetic phase transition the fluctuations are at very low energies for 

long wavelenth. This experimental finding is also present in a first implementation of our theory. 

The presented approach is also applicable to other correltated fermi systems e.g. electrons and 

dipols in two dimensions. We predict this transition of the collective mode seen in 3He also for two 

dimensional electrons. The capability in describing these systems is investigated. 

Bohm, H. M., Holler, R., Krotscheck, E. & Panholzer, M. Dynamic many-body theory: Dynamics of 

Strongly Correlated Fermi Fluids. Phys. Rev. B 22, 224505 (2010). 

RG16 

The induced effects of the Dzyaloshinskii-Moriya interaction on the 

thermal entanglement 

Saeed Mahdavifar* 

Department of Physics, University of Guilan, Iran 

The pairwise thermal entanglement in one-dimensional (1D) spin-1/2 XX model with 

added Dzyaloshinskii-Moriya interaction and transverse magnetic field is studied 

through fermionization technique. We have showed that, for fields less than quantum 

critical point, the thermal entanglement decreases by increasing the temperature and 

vanishes at a field-independent critical temperature. On the other hand for fields 

more than quantum critical value of the magnetic field (Fig. (1)(b)), NN spins are 

not entangled at $T=0$. By increasing the temperature from zero, NN spins remain 

unentangled up to the first critical temperature $T_{c_{1}}(h)$. As soon as the 

temperature increases from $T_{c_{1}}$, the thermal entanglement regain and 

takes a maximum value and then decrease and reaches to zero at the second critical 

temperature $T_{c_{2}}(h)$. 


RG17 

Magneto-polaronic effects in molecular transistors as the consequence 

of quantum uncertainty of the displacement of vibrating quantum dot. 

Glib A(alexandrovich) Skorobagatko 1 *, Sergey I. Kulinich 2 , Ilya V. Krive 3 and Robert 

I. Shekhter 4 

1 

Department of Theoretical Physics, B.Verkin ILTPE of NAS of Ukraine, Kharkov, 

Ukraine, Ukraine 

2 

Department of Theoretical Physics, B.Verkin ILTPE of NAS of Ukraine, Kharkov, 

Ukraine, Ukraine 

3 

Department of Theoretical Physics, B.Verkin ILTPE of NAS of Ukraine, Ukraine 

4 

Department of Physics,, University of Gothenburg, SE-41296, Gothenburg, Sweden, 

Sweden 

The influence of magneto-polaronic effects induced by the quantum uncertainty of 

the displacement of quantum dot on electron transport through a single-level vibrating 

quantum dot subjected to a transverse (to the current flow) magnetic field is considered 

. It is shown that the effects are most pronounced in the regime of sequential electron 

tunneling, where a polaronic blockade of the current at low temperatures and an 

anomalous temperature dependence of the magnetoconductance are predicted. 

1. G. A. Skorobagatko, S. I. Kulinich, I. V. Krive, R. I. Shekhter, and M. Jonson, Low Temp. Phys. 37, 

1032 (2011). 

RG18 

Defect states and electron correlations in multi-orbital Mott insulators 

Adolfo Avella 1 *, Peter Horsch 2 and Andrzej Oles 3 

1 Dipartimento di Fisica 'E.R. Caianiello', Universita degli Studi di Salerno, Italy 

2 Max Planck Institute for Solid State Research, Stuttgart, Germany 

3 Jagellonian University, Krakow, Poland 

We address the role played by defects in doped Mott insulators with active orbital 

degrees of freedom. We observe that defects are characterized by rather complex 

and rich physics which is well captured by a degenerate Hubbard model extended by 

several terms that describe crystal-field splittings, the orbital-lattice coupling, as well 

as local terms generated by defects such as the Coulomb potential terms that act both 

on a doped hole and orbitals of undoped sites (orbital polarization). We show that 

the multiplet structure of excited states generated in such systems by strong electron 

interactions is well described in an optimized unrestricted Hartree-Fock approximation, 

taking into account the usual symmetry breaking by the onset of magnetic and orbital 

order. More importantly, we show that defect states are responsible for new features 

that arise within the Mott-Hubbard gap and in the multiplet spectrum at high energy. 

These states involve active orbital flavors at atoms b eing nearest neighbors of the 

defect state, which are modified by the local defect-orbital Coulomb interactions. 

The present study suggests a new mechanism for the Coulomb gap realized in the 

presence of defect states and investigates the dependence of the orbitals on the orbital 

polarization. 

RH01 

Magnetism of the noncentrosymmetric compound CeNiC 2-pressure 

effects 

Susumu Katano*, Toshiaki Kobayashi and Tohru Yoshida 

Graduate School of Science and Engneering, Saitama University, Japan 

The system RNiC 2 (R=Rare-earth element) has a simple but a characteristical 

noncentrosymmetric crystal structure, and shows various novel physical properties such 

as charge density waves (CDW) and complex magnetic structures. In the system the 

compound of R=La shows unconventional superconductivity, and has been intensively 

studied very recently. For CeNiC 2 a few reports indicated that the incommensurate 

antiferromagnetic state (ICAF) appears at around 20 K and this changes to the 

commensurate antiferromagnetic structure (CAF) at about 10 K, then a ferromagnetic 

state (F) takes place at around 2 K [1, 2]. However, since there are some clear 

discrepancies in these studies the magnetism of this compound has been reinvestigated 

in detail using a carefully prepared polycrystalline sample. It is found that there are 

definite magnetic moments in the paramagnetic state. With these moments the complex 

antiferromagnetic states undergo, which replaces to a ferromagnetic state at low 

temperatures. To investigate these magnetic states further, their pressure effects have 

been studied up to 2.5 GPa. The results show that the IC and CAF states at the higher 

temperatures is fairly stable, whose transition temperatures increase at a rate of about 2 

K/GPa. On the other hand the F state is changed little. 

[1] K. Motoya, et al. J. Phys.Soc. Jpn. 66 (1997) 1124. [2] V.K. Pecharsky, et al. Phys. Rev. B 58 

(1998) 497.

RH02 

Atomic scale disorder driven bicritical region in Sm0.5(Ca 1xSrx)0.5MnO 

3 

Saurav Giri 1 *, Sk. Sabyasachi 1 , S. Majumdar 1 , S. Das 2 and V. S. Amaral 3 

1 Solid State Physics, Indian Association for the Cultivation of Science, India 

2 Department of Physics and CICECO, University of Aveiro, Portugal 

3 Department of Physics and CICECO, University of Aveiro, India 

On the verge of collapse of charge and orbital ordering a bicritical region occurs in hole doped 

manganites which displays rich electronic phase diagrams in R0.5(Ca,Sr)0.5MnO 3 [1]. Here, 

we demonstrate a fascinating consequence of A-site disorder in intermediate members of a 

new series Sm0.5(Ca 1-xSrx)0.5MnO 3. The Rietveld refinement of X-ray diffraction studies 

reveal maximum structural distortions at x = ½. This is indicated by the highest value of ε [= 

√2b/(a+c), a, b, c being lattice constants] and most deviation of Mn-O-Mn bond-angle from 

180° compared to end compounds. An unusual behaviour in magnetic field-induced ultrasharp 

transition to ferromagnetic metallic (FMM) state and collapse of charge ordering is 

observed both in magnetization and magnetoresistance curves for intermediate compositions 

at much lower field compared to end compounds. When magnetic field is applied above 

a critical field, FMM state appears and it retains high-field state, although magnetic field 

decreased to zero. With decreasing field sweep rate, the transition shifts to higher field 

indicating a meta-magnetic transition. The atomic-scale local inhomogeneity/distortion arising 

from the difference in ionic radii and/or the random Coulomb potential from ion mixture is 

supposed to be critical behind such striking phenomena. 

[1] Y. Takura, Rep. Prog. Phys. 69, 797 (2006). 

RH03 

11B-NMR study on Shastry Sutherland system TbB4 Tomoki Muto 1 , Takayuki Goto 1 , Akira Oosawa 1 , Shunsuke Yoshii 2 , Takahiko Sasaki 3 , Shinji 

Michimura 4 , Fumitoshi Iga 4 and Toshiro Takabatake 4 

1 

Department of Physics, Sophia University, Japan 

2 

CINTS Tohoku University, Japan 

3 


4 

ADSM, Hiroshima University, Japan 

In TbB 4, the arrangement of Tb ions within the c-plane is topologically equivalent to the 

Shastry Sutherland (S-S) lattice with geometrical frustration [1]. A well-known example 

of S-S lattice is SrCu 2(BO 3) 2 which shows the characteristic magnetization plateaus 

caused by the frustration. However, in TbB 4, due to the quadrupole interaction and 

RKKY interaction between classical spins, the appearance of the novel magnetism quite 

different from SrCu 2(BO 3) 2 is expected. The magnetization of TbB 4 for H // c-axis shows 

field-induced multi-step jump while the magnetization in the c-plane on which we focus 

attention shows only one large jump at Hc = 15.9 and 12 T for H//[100] and H//[110] 

respectively [2]. In order to investigate the magnetic structure in high magnetic fields for 

H//[100], we performed 11B-NMR experiments up to 17.5T for the single crystalline 

TbB 4. 11B-NMR spectra observed at low magnetic field changes drastically at Hc = 15.9 

T, where the magnetization jump occurs. This result indicates the change of the magnetic 

structure at the field-induced magnetic phase transition. In order to determine the 

magnetic structure, we have compared the observed NMR spectra with the calculation 

based on the classical dipole-dipole interaction. 

[1] B.S.Shastry et al., Physica B 208 (1981) 1069. [2] S.Yoshii et al., Phys. Rev. Lett. 101 (2008) 087202. 

RH04 

Magnetotransport Property of the Hole-doped Delafossite 

CuCr 0.97Mg 0.03O 2 with a Spin-3/2 Antiferromagnetic Triangular 

Sublattice 

Tetsuji Okuda 1 *, Satoshi Oozono 1 , Takumi Kihara 2 and Masashi Tokunaga 2 


2 The University of Tokyo, ISSP, Japan 

Magnetotransport property of a hole-doped delafossite CuCr 0.97Mg 0.03O 2 with a spin- 

3/2 antiferromagnetic (AF) triangular sublattice was investigated by a pulsed high 

magnetic field up to about 56 Tesla. [1] A dramatic change of magnetoresistance (MR) 

was observed with a variation of temperature (T), which is due to a development of 

an AF correlation with a decrease in T. A negative MR is observed and the ratio is 

well proportional to a square of magnetization above a Curie-Weiss temperature (θ), 

which seems to suggest that the magnetic state above θ is well explained by a Kondolattice 

model [2] with a weak ferromagnetic Hund’s coupling between itinerant holes 

and localized spins. However, below θ, the negative MR gradually deviates from the 

scaling relation with a decrease in T and is much enhanced around an AF transition 

temperature (TN). Furthermore, a component of positive MR appears around TN. Such 

a MR behavior is due to a critical enhancement of spin fluctuation around TN, which 

may cause a nontrivial promotion of a 120° AF state by the Mg substitution [3,4]. 

[1] T. Okuda, S. Oozono, T. Kihara, and M. Tokunaga, in preparation. [2] N. Furukawa, J. Phys. Soc. 

Jpn. 63, 3214 (1994). [3] T. Okuda, N. Jufuku, S. Hidaka, and N. Terada, Phys. Rev. B 72, 144403 (2005). 

[4] T. Okuda, Y. Beppu, Y. Fujii, T. Onoe, N. Terada, S. Miyasaka, Phys. Rev. B 77, 134423 (2008). 

RH05 

RH06 

RH07 


Lifshitz transition with interactions in high magnetic fields: application 

to CeIn 3 

Pedro Schlottmann* 

Department of Physics, Florida State University, USA 

MOVED 

Novel colossal magnetoresistance in NaCr 2 O 4 

Hiroya Sakurai 1 *, Taras Kolodiazhnyi 1 , Yuichi Michiue 2 and Eiji Takayamamuromachi 

2 

1 Superconducting Properties Unit, National Institute for Materials Science, Japan 


We recently discovered new chromium oxide, NaCr 2 O 4 , to have calcium ferrite 

type structure, in which spin frustration is expected. The compound shows cantedantiferromagentic 

transition at TN = 125 K and Arrhenius-type temperature dependence 

of electrical resistivity. The resistivity below TN is greatly suppressed by magnetic field 

and it remains to be a finite value at 0 K under H = 9 T. Thus, the magnetoresistance 

ratio, {rho(H)-rho(0)}/rho(0), becomes closer to -100% at low temperatures. The 

similar behavior has been observed in some manganites, such as Pr 0.7Ca 0.3MnO 3 and 

Nd 0.5Sr 0.5MnO 3, for which the competition between charge-ordered insulating phase 

and ferromagnetic metallic phase causes colossal magnetoresistance (CMR) through 

the first-order transition. Unlike them, however, NaCr2O4 shows no thermal or field 

hysteresis in its physical properties, and there is no ferromagnetic metallic phase 

compositionally close to NaCr 2O 4. Therefore, CMR of the compound is considered to 

be caused by a new mechanism. The magnetism of Ca1-xNaxCr 2O 4 strongly suggests 

unusual electronic state of Cr 4+ ions. We will present a possible mechanism of CMR in 

NaCr 2O 4, in which spin frustration and the electronic state of Cr 4+ ions play a key role. 

Low field study of Hall effect in GdB6 M. A. Anisimov 1 *, A. V. Bogach 1 , V. V. Glushkov 1 , S. V. Demishev 1 , N. A. Samarin 1 , N. 

Yu. Shitsevalova 2 , A. V. Levchenko 2 , V. B. Filipov 2 and N. E. Sluchanko 1 

1 

Low Temperatures and Cryogenic Engineering Dept., A.M.Prokhorov General 

Physics Institute of RAS, Russia 

2 

Institute for Problems of Materials Science NAS, Ukraine 

GdB 6 plays the important role for understanding of the mechanisms responsible for the 

antiferromagnetic (AF) state formation in the rare earth hexaborides. However the magnetic 

structure of GdB 6 which is characterized by two successive AF transitions (AF(I) ordering 

below T_N~15.5K, and AF(II) phase at T^*~4.7K) is still the subject of discussion [1]. In 

current work we present the comprehensive study of Hall effect on the high quality single 

crystals of GdB 6 in the wide temperature interval (2-120K) at low magnetic fields (H≤1T). In 

paramagnetic state Hall coefficient R_H is practically temperature independent and value of 

R_H~-4•10^{-4}cm^3/C detected with the high accuracy is in accord with the results of light 

hexaborides RB 6 (R-La, Ce, Pr, Nd) published previously [2],[3]. The temperature decrease 

below T_N induces the drastic enhancement of negative Hall coefficient (ΔR_H/R_H~ 64%). 

The magnetic ordering at T^* (AF(I)-AF(II) transition) is accompanied by the appearance of 

anomalous Hall effect which is detected in GdB 6 for the first time. The complex analysis of 

charge transport parameters suggests the possible effect of 5d-states spin density polarization 

in AF and PM states of GdB 6. 

[1] M.Amara, S.E.Luca et al., Phys. Rev. B v. 72, p. 064447 (2005). [2] Y. Onuki, A.Umezawa et al., Phys. Rev. B v. 

40, p. 11195 (1989). [3] M.A.Anisimov, A.V.Bogach, V.V.Glushkov et al., arxiv cond-mat:1006.0124v1 


Poster Thursday



RH08 

Theoretical study of structures and mechanical properties of M-type 

hexagonal ferrites BaFe 12O 19 

Wonha Moon*, Soyeon Kim, Heejung Lee, Jaehoon Yeom, Sangwon Lee and Seok 

Bae 

LG innotek, Korea 

M-type hexagonal ferrite, BaFe 12O 19, has extensively studied in a wide range of 

applications such as microwave devices and permanent magnets due to high Curie 

temperature, large saturation magnetization and good chemical stability. In this paper, 

we have investigated the structure and elastic modulus of BaFe 12O 19 using atomistic 

simulations. An interatomic potential based on the shell model is used for the structure 

and properties of BaFe 12O 19. The shell model has been extensively used to a wide range 

of oxide materials since it is a simple and useful potential with the Coulomb interaction 

incorporated with the short-ranged term for ionic characteristics, though it is incapable 

of describing the elemental components. The calculated results are in agreement 

with experiments and previous theoretical studies. To our knowledge, although many 

theoretical investigations have so far played an important role in understanding the 

properties of magnetic materials, there have been few theoretical studies using the 

interatomic potential for the structure and properties of BaFe 12O 19. The interatomic 

potential employed has been shown to be capable of describing the Ba-based hexagonal 

ferrites. 

1. P. Shepherd, K. K. Mallick and R. J. Green, J. Magn. Magn. Mater. 311 (2007) 683. 2. G. V. Lewis and C. R. A. 

Catlaw, J. Phys. C: Solid State Phys. 18 (1985) 1149. 3. P. Novak and J. Rusz, Phys. Rev. B 71 (2005) 184433. 

RH09 

Nonlinear susceptibility of gadolinium near curie temperature 

Takashi Shirane* and Shohei Sakurai 

Sendai National College of Technology, Japan 

The ac linear and nonlinear susceptibilities of an elemental ferromagnetic gadolinium 

have been studied near the Curie temperature, to clarify the feature of the magnetic 

phase transition with special emphasis on the behavior below the Curie temperature. 

The temperature dependence of linear susceptibility is in good agreement with that of 

an experimental result reported in ref. [1]. The first observation for the critical behavior 

of the nonlinear susceptibility in gadolinium has been made at various field amplitudes. 

The behavior of the nonlinear susceptibility is very sensitive to the field amplitude. The 

field dependence of the susceptibilities are explained on the basis of a mean field theory 

taken into account the domain structure[2]. The detailed discussion will be shown the 

full paper in comparison with magnetization curves at various temperature below the 

Curie temperature. 

[1] J. M. D. Coey, K. Gallangher, and V. Skumryev, J. Appl. Phys. 87 (2000) 7028. [2] T. Shirane, 

Statistical and Condensed Matter Physics: Over the Horizon, ed. S. Fujita, T. Obata, and A. Suzuki 

(New York: Nova Science), p. 189-197, (2007). 

RH10 

Electron correlation and dynamical Jahn-Teller effect in orbitally 

degenerate system 

Joji Nasu and Sumio Ishihara* 


Quantum spin liquid state is one of the attractive subjects in correlated electron 

systems. Recently, a possibility of the quantum spin liquid state is experimentally 

reported in a layered copper oxide Ba 3CuSb 2O 9 where the orbital degree of freedom 

in a Cu ion and the dynamical Jahn-Teller effect (DJTE) are suggested to play some 

roles on an origin of the spin liquid state. Motivated from these recent experimental 

results, we study the DJTE in a spin-orbital coupled system. In particular, we focus 

on competitive or cooperative phenomena between the superexchange interaction and 

the DJTE. A superexchange interaction part is derived from the d-p model and the 

DJTE part for the low lying vibronic states is described by the orbital pseudo-spin and 

the lattice vibration. We analyze the model which combines the two interactions on 

a honeycomb lattice by using the Bethe approximation and the exact diagonalization 

method. We find that the magnetic order is unstable in a wide parameter region and a 

spin-singlet dimer state associated with an orbital order is realized. With increasing the 

DJTE, furthermore, the orbital order is strongly suppressed and a resonance state of the 

spin-orbital dimers appears. 

H. D. Zhou, et.al., Phys. Rev. Lett., 106 (2011) 147204. 


RH11 

High-field NMR study on the charge in stability in quantum spin 

system Cu 3Mo 2O 9 

Keita Misoka 1, Takayuki Goto 1*, Haruhiko Kuroe 1, Tomoyuki Sekine 1, Takahiko Sasaki 2, Masashi 

Hase 3, Kunihiko Oka 4, Toshimitsu Ito 4 and Hiroshi Eisaki 4 

1 Department of Phisics, Sophia University, Japan 


3 Department of Phisics, National Institute for Materials Science, Japan 

4 National Institute of Advanced Industrial Science and Technology, Japan 

The quasi-one-dimensional quantum spin system Cu 3Mo 2O 9 with the two spin-degrees of 

freedom, antiferromagnetic chain and dimer-like sites clinging around the chain undergoes 

the long-range antiferromagnetic order at 7.9 K, associated with a weak ferromagnetic 

moment. The system shows a small magnetization jump of 0.0033 μB at H* = 8.2 T, where 

the anomalous charge instability appears [1], suggesting an existence of tight coupling 

between spin and charge. In order to inverstigate the microscopic spin and charge states in 

the high magnetic field, we have utilized Cu-NMR technique, which separately probes the 

spin and charge in the chain site Cu 1, the dimer like sites Cu 2 and Cu 3 through hyperfine 

coupling and electric quadruple interaction respectively. In this presentation, we show by 

detailed analyses of spectra taken under a wide range of filed up to 17.5 T that the ordered 

antiferromagnetic moment is dominated by Cu 1, while the dimer-like sites only feel a 

uniform hyperfine field but staggered one, and that the change inhomogenization takes 

place in Cu 2 and Cu 3 in the vicinity of the field of magnetization jump H*. 

1 T. Hamasaki et al., Phys. Rev. B77 134419 (2007). 

RH12 

Anisotropic spin excitations in spin-Peierls CuGeO3 Kazuhiko Ikeuchi 1 , Fumio Mizuno 2 , Ryoichi Kajimoto 1 , Yasuhiro Inamura 3 , Mitsutaka Nakamura 3 , 

Kenji Nakajima 3 , Masaki Fujita 4 , Kazuya Aizawa 3 and Masatoshi Arai 3 

1 

Research Center for Neutron Science and Technology, Comprehensive Research Organization for 

Science and Society, Japan 

2 


3 

Neutron Science Section, J-PARC Center, Japan 

4 

Institute for Material Research, Tohoku University, Japan 

Even though CuGeO 3 is a well-known 1-dimensional quantum spin system that shows magnetic 

transition into a dimerized state with a spontaneous lattice distortion, it is not clear whether it is 

an archetypal material of a spin-Peierls system. In fact, neutron scattering experiment has still not 

succeeded in assignment of the soft phonon mode accompanying the magnetic transition. Actually, 

due to an antiferromagnetic coupling between the neighboring spin chains, the dimerization in the 

spin chain is close to the critical state [1][2][3], and it should not have a strong effect on a phonon. In 

this time, we performed inelastic neutron scattering experiment on CuGeO 3 with the Fermi chopper 

spectrometer 4SEASONS at MLF/J-PARC in Japan. In order to further understand the inter-chain 

coupling, we measured intensity-maps in a 4-dimensional (q,ω) space including the inter-chain 

direction due to rotation of the aligned 17.2 g CuGeO 3 single crystals in horizontal plane. In this 

experiment, we have clarified an anisotropy of the magnetic excitations below the spin-Peierls 

transition temperature. This result suggests the inter-chain coupling correlates with the dimerization 

in the spin-Peierls state on CuGeO 3. We will present the detail of the magnetic excitations together 

with new other features recently discussed in several theoretical models. 

[1] M. Nishi et al., PRB, 50,6508 (1994). [2] J. Riera et al., PRB, 51,16098 (1995). [3] M. C. Martin et al., PRB, 56, 3173 (1997). 

RH13 

Neutron inelastic scattering on spin-peierls system TiOBr 

Tetsuya Yokoo 1 , Shinichi Itoh 1 , Daichi Kawana 1 and Jun Akimitsu 2 

1 High Energy Accelerator Research Organization, Japan 

2 Aoyama Gakuin University, Japan 

Newly proposed spin-Peierls system TiOX (X: Cl, Br) has been revealed showing 

exotic structural and magnetic properties such as a successive phase transition, onedimensional 

(1D) nature associated with orbital ordering of Ti ions and super-lattice 

structure being related to the Peierls instability. It is pointed out that resulting only from 

an arrangement of Ti dxy orbital, the formation of 1D spin chains and the spin-Peierls 

transition will be realized. Recently, it has been demonstrated that TiOBr also exhibits 

two successive phase transitions similar to TiOC l at Tc1=27K and Tc 2=47K. Here we 

carried out inelastic neutron experiments in order to see the evidence of spin-Peierls 

transition. The inelastic spectrum with a large amount of poly crystalline sample of 

TiOBr shows the localized signal in the vicinity of the magnetic zone center Q=0.9A-1. 

Observed spin gap like signal lies at energy of ΔE=10meV. The gap energy in TiOBr is 

expected much higher from measured thermodynamic properties and by analogy with 

TiOCl. Constant Q cuts of the observed S(Q,E) map show some Q-dependent structure 

in its intensity indicating the signal is sample oriented. The Q structure quite reveals 

the intensity is well explained by the powder averaged dynamical structure.

RH14 

Physical properties of the novel triangular-lattice silver oxides Ag 2MO 2 

(M = Co, Ga, Rh) 

Hiroyuki Yoshida and Masaaki Isobe 


Triangular antiferromagnets have been extensively studied by many scientists in terms 

of geometrical frustration. According to current theories, triangular antiferromagnets 

show various exotic magnetic properties, e.g. chirality order, Kosterlitz-Thouless 

transition, a partially disordered state, etc. A series of layered Ag 2MO 2 compounds, 

where M is a transition metal, are possible model compounds of triangular 

antiferromagnets. The crystal structure of Ag 2MO 2 consists of alternate stacks of an 

M 3+ O 2 layer and a (Ag 2)+ layer. The former includes a triangular lattice of the M 3+ ions, 

while the latter provides itinerant electrons from the quarter-filled Ag 5s band. The 

triangular lattices are well separated from each other by the non-magnetic double Ag 

layer. A path does not exist for superexchange interaction between the M 3+ spins on the 

adjacent triangular lattices. In addition, no cation disorder is expected between the M 

and Ag ions. Ag 2MO 2 is, therefore, considered a suitable system to study the magnetic 

properties of triangular antiferromagnets. We recently succeeded in synthesizing 

Ag 2MO 2, M = Co, Ga, Rh, for the first time using a high-pressure technique. The 

details of physical properties of Ag 2MO 2 will be reported. 

RH15 

Electrical and thermal transport properties of the polycrystalline 

(Cr 86Ru 14)1-xVx alloy system 

Leelakrishna Reddy, Aletta Roletta Prinsloo, Charles Johannes Sheppard and Andre 

Micheal Strydom 

Physics, University of Johannesburg, South Africa 

Thermopower (S) and electrical resistivity (ρ) measurements on the (Cr 86Ru 14)1xVx 

alloy system with 0≤x≤0.144 reveal unique behaviour[1,2,3]. The onset of a 

commensurate (C) itinerant-electron antiferromagnetic spin-density-wave (SDW) 

structure is marked by anomalies in ρ(T) and S(T), associated with the Neel temperature. 

Focus is on the thermopower as it is more sensitive to the changes in the electronic 

structure and scattering mechanisms that are of importance at the SDW transition[2]. 

For this series S(T) shows a broad valley for x≤0.032. The valley gradually becomes 

more shallow with increasing x and is eventually replaced by a surplus of positive 

thermopower for x=0.074, for which parallelism is seen between ρ(T) and S(T) as 

in the case of Cr-V[2]. The size of the magnetic contributions to S and ρ strongly 

correlates and decreases with increasing x; attributed to the addition of V to the system 

that destabilizes the CSDW structure. The effect of the addition of V will be explained 

in terms of a model that relates the behaviour of S(T) to the energy dependence of the 

decrease in the scattering rate of electrons by phonons and an increase in the resistivity 

on decreasing temperature due to a decrease in the Fermi surface area[3]. 

[1] L. Reddy et al., J. Appl. Phys. 103 (2008) 07C903-1. [2] E. Fawcett et al., Rev. Mod. Phys. 66 

(1994) 25. [3] A. L. Trego et al., Phys. Rev. 166 (1968) 495. 

RH16 

Magnetic properties of the layered triangular-lattice antiferromagnets 

CsM(MoO 4)2 (M=V, Fe) 

Masahiko Isobe and Yutaka Ueda 

ISSP, Univ. of Tokyo, Japan 

Two-dimensional triangular lattice antiferromagnets are of great interest concerning 

the ordering in frustrated spin system. We have prepared powder samples of the 

layered triangular-lattice antiferromagnets CsFe(MoO 4)2 and CsV(MoO 4)2 and have 

investigated the magnetic properties. In CsFe(MoO 4)2, a structural phase transition at 

around 365K from P3m1 to P3 was detected. Also we observed the magnetic transition 

at 4.4 K for CsFe(MoO 4)2 and 26 K for CsV(MoO 4)2. The magnetic properties of 

CsFe(MoO 4)2 are similar to that of the multiferroic RbFe(MoO 4)2. 

RH17 

RH18 

RH19 


Kitaev-Heisenberg magnetism in honeycomb iridates A 2IrO 3(A=Li,Na) 

Akihiko Kato 1, Tomohiro Takayama 2* and Hidenori Takagi 3 

1 Department of Applied Chemistry, University of Tokyo, Japan 

2 Department of Advanced Materials Science, University of Tokyo, Japan 

3 Department of Physics, University of Tokyo, Japan 

5d transition-metal oxides can have unique properties because of the strong spin-orbit coupling and 

relatively weak electron correlations. Layered perovskite iridate Sr 2IrO 4, for example, was revealed 

to be Jeff=1/2 Mott-insulator where spin and orbital degrees of freedom are entangled with including 

complex phase i[1]. The magnetism of such Jeff=1/2 Mott-insulator might be different from 3d 

transition-metal Mott-insulator.Indeed in iridates, the superexchange coupling between Ir-O-Ir was 

proposed to be anisotropic ferromagnetic when IrO 6 octahedra form edge-sharing network, due 

to the complex phase[2]. As a consequence, the spin-liquid state based on the Kitaev-model was 

theoretically predicted when such edge-shared IrO 6 octahedra compose a honeycom network. Such 

unique lattice topology can be found in layered iridatesA 2IrO 3(A=Li,Na). Na 2IrO 3 is a frustrated 

antiferromagnet with Tn=17K, and the θw=-125K. The strong antiferromagnetic interaction is 

likely due to direct interaction between Ir 5d electrons. Meanwhile, Li 2IrO 3 exhibited less frustrated 

magnetism with Tn=12K and θw=-12K, even with the similar structure. We argue that this seemingly 

non-frustrated magnetism of Li 2IrO 3 likely originates from a coexistence of direct antiferromagnetic 

and ferromagnetic superexchange interaction, exemplifying the Kitaev-Heisenberg model[3]. The 

difference might come from the local structure, the honeycomb of Na 2IrO 3 is distorted but that of 

Li 2IrO 3 is closer to ideal honeycomb. 

[1] B.J.Kim et al., Science 323,1329(2009) [2]G.Jackeli and G.Khaliullin, Phys.Rev.Lett. 102,017205(2009) [3] 

J.Chaloupka et al., Phys.Rev.Lettt. 105,027204 (2010) 

Effects of the annealing conditions on the magneto-transport 

properties of La 0.7Sr 0.3Mn 1+dO 3-manganese oxide composites 

Sang-im Yoo 1 * and Hyo-jin Kim 2 

1 Department of Materials Science and Engineering, Seoul national university, Korea 

2 Department of Materials Science and Engineering, Seoul National University, Korea 

The effects of the annealing conditions on the magneto-transport properties of 

the pure La 0.7Sr 0.3MnO 3(LSMO) and LSMO-manganese oxide composites were 

carefully investigated in this study. While the ferromagnetic-paramagnetic transition 

temperatures of all polycrystalline samples were insignificantly varied in the range 

of 359~368 K, low field magnetoresistance (LFMR) properties and dMR/dH values 

were remarkably improved for the composite samples annealed at relatively high 

temperature. For instance, with increasing the annealing temperature from 1300 to 

1450°C, the LFMR ratios of 95 mol% LSMO - 5 mol% Mn2O3 composite sample 

were increased from 0.8 % to 1.1 % at 300 K in 0.5 kOe, suggesting that a magnetic 

disorder at the LSMO grain boundary, known as a key factor suppressing effective 

spin-dependent scattering, could be greatly improved by high temperature annealing 

process. Detailed annealing effects on the magneto-transport properties of samples 

will be presented for a discussion. This work was supported by the Korea Research 

Foundation Grant funded by the Korean Government (MOEHRD, Basic Research 

Promotion Fund) (KRF-0417-20100021) 

Temperature dependence of spin lattice relaxation time of proton 

NMR in mixed antiferromagnets A 1-xBxC l2-2H 2O 

Tatsuichi Hamasaki 1 , Kazuko Zenmyo 2 and Hidenori Kubo 2 

1 Physics Department, Kyushu Sangyo University, Japan 

2 Fukuoka Institute of Technology, Japan 

In the mixed antiferromagnet systems Ni 1-xCoxC l2_2H 2O and Ni1-xMnxC l2_2H 2O, 

the Co substitution increases a little the transition temperature and the Mn substitution 

decreases the transition temperature rapidly. In Ni-Co system, the concentration 

dependence of the phase transition temperature is well explained by simple molecular 

field theory. But, in Ni-Mn system, molecular field theory cannot explain it sufficiently. 

Thus Mn spins in NiC l2_2H 2O crystal show the peculiar behavior. Then, we have 

measured the temperature dependence of the spin-lattice relaxation time of proton 

NMR, in order to understand the specificity of the Mn spins. We have prepared the 

mixed antiferromagnets A 1-xBxC l2-2H 2O (A, B=Co, Mn, Ni). In Co-M (M=Ni, 

Mn) system, in comparison with the Ni substitution, the Mn substitution induces a 

significant impact on the relaxation time. In Mn-M (M=Ni, Co) system, the relaxation 

time is affected by a small amount of substitution. In Mn-Co system, the reentrant 

spin-glass phase appears at low temperature. The strange behavior of the relaxation 

time at low temperature is believed to reflect that. A similar trend is seen at the low 

temperatures in the case of Ni substitution, too. We suppose that this may be attributed 

to a kind of the instability of Mn spins. 


Poster Thursday



RH20 

Electronic Structure and magneto-optical properties of Co 2MnX alloys 

where X = Ge, Sn and Pb: a first-principles investigation in LDA+U 

approach 

Tran Van Quang 1 , Jae Il Lee 2 and Miyoung Kim 3 

1 Dept. of Physics, Ajou University, Suwon 443-749, Korea 

2 Dept of Physics, Inha University, Incheon 402-751, Korea 

3 Division of Energy System Research, Ajou University, Suwon 443-749, Korea 

We report our ab initio calculational results on the electronic structures and magnetooptical 

(MO) properties of the ferromagnetic Co 2MnX alloys where X= Ge, Sn and 

Pb. Employing the +U corrections for the 3d valence bands of transition metal atoms 

in addition to the conventional local density approximation (LDA), we investigate the 

correlation effect on the MO spectra in polar geometry as well as the detailed electronic 

structures using the all-electron FLAPW [1] method. Results show that the correlation 

effect results in a blue-shift of the peak positions and the large enhancement of the MO 

spectra compared to the LDA results. We find that our results can be attributed to the 

increased t2g-eg splitting of spin minority d-bands of both Co and Mn atoms, which 

indicates the suppression of diagonal elements of optical conductivity at energy region 

of 1~2 eV where the interband transitions are forbidden.[2] 

[1] E. Wimmer, K. Krakauer, M. Weinert, and A. J. Freeman, Phys. Rev. B 24, 864 (1981). [2] 

Support by Basic Science Research Program (NRF-2010-0005387) and Priority Research Centers 

(2010-0029617) through the National Research Foundation of Korea. 

RH21 

2D Heisenberg antiferromagnetism in spin-orbit Mott insulator Sr 2IrO 4 

Akiyo Matsumoto 1 , Tomohiro Takayama 1 and Hide Takagi 2 * 

1 Department of Advanced Materials, The University of Tokyo, Japan 

2 Department of Physics, The University of Tokyo, Japan 

In 5d iridates, the interplay between spin-orbit coupling and modest electron correlation 

produces novel electronic phases. Sr 2IrO 4 was recently found to be a Jeff =1/2 Mott 

insulator where spin and orbital degrees of freedom are entangled[1]. The magnetic 

coupling between such Jeff = 1/2 state, which could be critically different from that in 

3d-based Mott insulators, is of particular interest. For example, the magnetic coupling 

between Ir was theoretically proposed to be isotropic Heisenberg-type when IrO 6 octahedra 

form corner-sharing network[2]. We focused on Sr 2IrO 4 to reveal the magnetism of such 

spin-orbit Mott insulator. Sr 2IrO 4 crystallizes in a K2NiF4-type perovskite structure, and 

magnetically orders at 240K. We investigated the detailed magnetic susceptibilities on 

the single crystals. The ground state was found to be antiferromagnetism, and the inplane 

susceptibility steeply increases just above the transition temperature likely due to 

Dzialloshinski-Moriya interaction. Meanwhile, at higher temperatures, the in- and out-ofplane 

susceptibilities were almost isotropic. By analyzing the susceptibilities, we found that 

they can be well described by the 2D Heisenberg antiferromagnetism. This indicates that 

even in the limit of strong spin-orbit coupling, Sr 2IrO 4 displays the isotropic Heisenberg 

magnetism. This situation contrast with the 3d oxides, where spin-orbit coupling is 

responsible for magnetic anisotropy. 

[1] B. J. Kim et al., Science 323,1329 (2009) [2] G.Jackeli and G. Khaliullin, Phys. Rev. Lett. 102, 017205 (2009) 

RH22 

Magnetoresistance and magnetic properties of oxygen deficient (Sr,Y) 

(Fe,Co)O3 perovskites 

Jean-marie Le Breton 1 *, Youssef Rizki 1 , Yohann Breard 2 , Luc Lechevallier 1 and 

Antoine Maignan 2 

1 

Groupe de Physique des Materiaux - UMR 6634, CNRS - Universite de Rouen, 

France 

2 

CRISMAT, UMR 6508 CNRS, ENSICAEN - Universite de Caen, France 

The magnetic and magnetoresistive properties of oxygen deficient (Sr,Y)(Co,Fe) 

O 3 perovskites have been investigated in relation with the composition. The valence 

state of Fe has been probed by 57Fe Mossbauer spectrometry. Sr 1-xYxFe 0.8Co 0.2O 3-d 

and Sr 0.8Y 0.2Co 1-xFexO 3-d series were more particularly investigated. It appears that the 

progressive replacement of Sr2+ by Y3+ and the Co/Fe substitution lead to a change 

of the valence state of Fe and to a drastic change of the magnetic and magnetoresistive 

properties, in relation with the variation of the Fe4+/Fe3+ ratio and the change in 

the oxygen content. It is shown that the Sr 0.8Y 0.2Co 0.5Fe 0.5O 3-d reveals the highest 

magnetoresistance effect, in relation with the fact that the magnetic field induced 

ferromagnetic alignement of the Fe/Co magnetic moments allows more metallic 

pathaways to be created. This work was supported by the French Agence Nationale de 

la Recherche (project ANR-08-BLAN-0005-01). 


RH23 

High field element selective magnetometry in erbium iron garnet 

Cornelius Strohm*, Thomas Roth, Peter J. E. M. Van Der Linden, Olivier Mathon and 

Sakura Pascarelli 

European Synchrotron Radiation Facility, 6 rue Jules Horowitz 38000 Grenoble, 

France 

Ferrimagnets play an important role for applications as well as from a fundamental point 

of view. The rare earth iron garnets for example were at the heart of the demonstration 

of the local molecular field theory [1] and later used for bubble memories, microwave 

devices and optival isolators. The ferrimagnetic superexchange between the rare earth 

and iron cations being mainly determined by bond angles and distances in the oxygen 

polyhedra, results in molecular fields of the order of tens of Tesla [2, 3]. We have perfomed 

element selective magnetometry on samples of Erbium Iron Garnet, using energy 

dispersive x-ray magnetic circular dichroism at the Fe K-edge and the Erbium L-edges. 

Pulsed fields of 30 T were generated by a high duty cycle miniature coil [4] and the signal 

was acquired using a multiframe detection scheme exploiting the entire pulse duration of 

1 ms [5]. Here we discuss mainly the results obtained at the Fe K-edge. At 65 K, below 

the compensation point, two successive field induced phase transitions and the reversal of 

the net magnetization of the Fe sublattices in the intermediate canted phase were observed, 

while the Fe signal remains unchanged at 100 K, above the compensation point. 

[1] L. Neel Science 174, 985 (1971). [2] A. E. Clark and E. Callen J. Appl. Phys. 39, 5972, (1968). [3] K. 

Nakao, T. Goto and N. Miura J. of Magn. Magn. Mat. 54, 1363, (1986). [4] P. J. E. M. van der Linden 

et al. Rev. Sci. Instrum. 79, 075104, (2008). [5] C. Strohm et al. J. of Synchrotron Rad. 18, 224, (2011). 

RH24 

THz and infrared excitation spectrum below the Jahn-Teller transition 

in Sr 3Cr 2O 8 

Zhe Wang 1 *, Michael Schmidt 1 , Franz Mayr 1 , Diana Quintero-castro 2 , A. T. M. 

Nazmul Islam 2 , Bella Lake 2 , Hans-albrecht Krug Von Nidda 1 , Alois Loidl 1 and 

Joachim Deisenhofer 1 

1 Experimental Physics 5, Intitute for Physics, Augsburg University, Germany 

2 Helmholtz-Zentrum Berlin fur Materialien und Energie, Germany 

We report on optical excitations observed recently in Sr 3Cr 2O 8 by THz and infrared 

spectroscopy. Low-energy excitations below 3 THz are detected by THz time domain 

spectroscopy including the spin singlet to triplet excitations.[1] These excitations 

can be divided into two different classes according to the temperaturedependent 

properties. One is emergent right below the Jahn-Teller transition temperature, which 

is determined by specific heat measurement to occur at 285 K. [1,2] The other appears 

only below 100 K, where the fluctuations are sufficiently suppressed, consistent with 

the temperature dependence of low-energy Raman modes. [3] Infrared transmission 

measurements reveal a broad crystal-field excitation, which can be associated with an 

electronic transition from E to T 2 orbital states. 

[1] Zhe Wang et al., Phys. Rev. B 83, 201102 (2011) [2] D. L. Quintero-Castro et al., Phys. Rev. B 

81, 014415 (2010) [3] D. Wulferding et al., Phys. Rev. B 84, 064419 (2011) 

RH25 

High-field multi-frequency ESR in the S=2 Heisenberg 

antiferromagnetic chain compound MnCl3(bpy) Masayuki Hagiwara 1 *, Shojiro Kimura 2 , Yuichi Idutsu 1 and Zentaro Honda 3 

1 


2 


3 


We report the results of high-field multi-frequency ESR experiments at 1.3 K on a 

powder sample of MnCl 3 (bpy) (bpy=2, 2'-bipyridine). This compound is one of the 

rare examples of the spin 2 quasi-one-dimensional Heisenberg antiferromagnets, and 

the magnetic properties on tiny single crystal samples were reported previously [1]. 

In our previous paper on this compound [2], we attained good agreement between 

experiment and calculation on the temperature dependence of magnetic susceptibility 

and the high-field magnetization process at 1.3 K. In this work, we have observed 

some high-frequency resonance modes with a zero-field gap of about 800 GHz that 

may correspond to the excitation modes at q=0 in the energy dispersion higher than the 

triplet excitation mode of about 50 GHz at q=pi expected from the evaluated exchange 

constant and the g-value. 

[1] G.E. Granroth et al., Phys. Rev. Lett. Vol. 77 (1996) 1616. [2] M. Hagiwara et al., to be 

published in J. Phys.: Conf. Ser.

RI01 

Distribution of magnetization in the random ising models. 

Kazuyuki Matsumoto 1 , Tatsuya Yoshimoto 1 , Hiroki Mizuno 1 , Takuya Okada 1 , Yosuke 

Ishikawa 1 and Yasuhiro Akutsu 2 

1 Department of Applied Sciences, Muroran Institute of Technology, Japan 

2 Department of Physics, Graduate School of Sciences, Osaka University, Japan 

We investigate the two- and three-dimensional random Ising models by the Monte 

Carlo method. The integrated distribution functions of site-magnetization are calculated 

above and below the lower Griffith temperature. It is found that these functions have 

distinct character above or below this temperature for the two-dimensinal random Ising 

model. However, for the three-dimensional random Ising model, this distinction cannot 

be observed on contrast to the two-dimensional random Ising model. This behavior 

may be explained by the percolation theory. 

RI02 

Berezinskii-Kosterlitz-Thouless trasition in two-dimensional p-state 

clock model 

Yuta Kumano*, Yusuke Tomita and Masaki Oshikawa 

ISSP, Japan 

In two dimensions, the Berezinskii-Kosterlitz-Thouless (BKT) transition occurs in 

models with the U(1) symmetry. The helicity modulus, which measures the rigidity 

against a global twist across the system, is useful for a detection of the transition 

because of its distinctive feature, the universal jump at the transition point. Meanwhile, 

in the p-state clock model which has the Z_p symmetry, it is believed that the BKT 

transition occurs when p is greater than 4 since the study by Jose et al. in 1977[1]. 

However, a recent numerical study by Baek et al. in 2010[2] detects an absence of the 

universal jump in the helicity modulus for p=5. This contradicts the Jose’s result. In this 

study, we show that the helicity modulus as defined by Baek (HMB) remains finite for 

any p with the high-temperature expansion. Therefore, the universal jump in the HMB 

cannot be observed whether the transition is the BKT or not. This casts a question on 

the physical meaning of the HMB. We will present a systematic study of the helicity 

modulus to clarify the universality class of the transition for p=5. 

[1] J. V. Jose, L. P. Kadanoff, S. Kirkpatrick and D. R. Nelson, Phys. Rev. B 16, 1217 (1977) [2] S. K. 

Baek and P. Minnhagen, Phys. Rev. E 82, 031102 (2010) 

RI03 

Influence of interplanar coupling on the entropy and specific heat of 

the bilayer ferromagnet 

Karol Szalowski and Tadeusz Balcerzak* 

Department of Solid State Physics, University of Lodz, Poland 

The Ising-Ising and Ising-Heisenberg bilayer with a simple quadratic lattice in 

each plane is studied using the pair approximation (PA) method. The foundation 

of formalism used has been developed in [1], where the phase diagrams for the 

anisotropic bi- and multilayer system have been obtained. In this paper the method 

(leading to a complete self-consistent thermodynamics) is adopted for the entropy 

and magnetic specific heat calculations. An interesting case is demonstrated when the 

exchange integrals in both planes are of unequal strength, and the interplanar coupling 

(Ising or Heisenberg) is relatively weak. In such a case, two peaks in the temperature 

dependence of the specific heat can be observed. The isothermal change of the entropy 

caused by application of the external magnetic field has been additionally calculated 

for a wide temperature range. The entropy change in the field also shows a double 

peak structure, similarly to the specific heat. Such a phenomenon may be of potential 

interest for investigations of the magnetocaloric effect. The results of the PA method 

have been compared with those obtained for two Ising-type planes by means of exact 

diagonalization for finite clusters. 

[1] K. Szalowski, T. Balcerzak, Physica A 391 (2012) 2197-2208. 

RI04 

RI05 

RI06 


Nontrivial ferrimagnetism of the heisenberg model on the union jack 

strip lattice 

Tokuro Shimokawa* and Hiroki Nakano 

University of Hyogo, Japan 

In low-dimensional quantum spin systems with frustration, nontrivial magnetic 

phenomena occur due to strong quantum fluctuation. One of the phenomena is a non- 

Lieb-Mattis (NLM) ferrimagnetism[1][2], which is different from the well-known 

Lieb-Mattis (LM) ferrimagnetism[3][4]. In contrast to the LM ferrimagnetism, 

the spontaneous magnetization of the NLM ferrimagnetism changes gradually 

with respect to the strength of frustration. Incommensurate modulation with longdistance 

periodicity in local magnetizations is also a characteristic behavior of the 

NLM ferrimagnetism. However, there are only a few cases revealing the NLM 

ferrimagnetism, which prevents us with understanding the mechanism of the 

occurrence of the NLM ferrimagnetism. In this study, we examine the ground-state 

properties of the S=1/2 Heisenberg model on the Union Jack strip lattice. We find the 

existence of the NLM ferromagnetism by the numerical diagonalization and density 

matrix renormalization group methods. We also discuss the relationship between the 

NLM ferromagnetic state of this strip lattice and the intermediate canted state of the 

S=1/2 Heisenberg model on the two-dimensional Union Jack lattice[5]. 

[1] S. Yoshikawa and S. Miyashita: J. Phys. Soc. Jpn. 74 (2005) Suppl. 71. [2] K. Hida: J. Phys.: Condens. Matter 

19 (2007) 145225. [3] W. Marshall: Proc. Roy. Soc. A 232 (1955) 48. [4] E. Lieb and D. Mattis: J. Math. Phys. 3 

(1962) 749. [5] R. F. Bishop, P. H. Y. Li, D. J. J. Farnell, and C. E. Campbell: Phys. Rev. B 82 (2010) 024416. 

Control of quantum critical points in bond disordered spin ladder 

materials 

S Ward 1 *, H Ryll 2 , D Biner 3 , K W Kramer 3 , K Kiefer 2 , D F Mcmorrow 1 and Ch Ruegg 4 

1 

London Centre for Nanotechnology, University College London, United Kingdom 

2 

Helmholtz Zentrum Berlin, Germany 

3 

Chemistry and Biochemistry, University of Bern, Switzerland 

4 

Laboratory for Neutron Scatering, Paul Scherrer Institut, Switzerland 

Spin ladders are model systems of low dimensional quantum spins. There is now 

considerable interest in materials which realise these ideal systems with solvable 

Hamiltonians and rich phase diagrams. An archetypal spin ladder material in the lowenergy 

regime is (C 5H 12N)2CuBr 4 whose phase diagram is completely accessible in 

laboratory magnetic fields. The rung (Jr) and leg (Jl) exchange are 12.8 K and 3.4 

K, respectively, and two field-controlled quantum critical points (QCPs) exist at 6.9 

T and 14.5 T. (C 5H 12N)2CuC l4 is a related spin ladder material. The superexchange 

between quantum Cu 2+ spins is controlled by the halide atoms and is lowered to 

Jr=3.4 K and Jl=1.3 K. The QCPs appear at the lower fields of 1.7 T and 4.3 T. A 

common structure and rich chemical flexibility in the superexchange pathways allows 

for partial halide substitution to create the bond disordered spin ladder materials 

(C 5H 12N)2CuBr 4(1-x)Cl4x, while retaining ideal spin ladder geometry. We present 

recent neutron scattering work and measurements of the magnetic and thermodynamic 

properties on the substitution series, and demonstrate explicitly substitution-controlled 

modification of exchange interactions as well as the effects of bond disorder on the 

spin ladder physics and QCPs. 

Triangular spin tubes with bond randomness 

Yoko Miura 1 * and Hirotaka Manaka 2 

1 Suzuka National College of Technology, Japan 

2 Department Graduate School of Science and Engineering, Kagoshima University, 

Japan 

We studied X-ray diffraction and magnetic susceptibility experiments on nonequilateral 

triangular spin tubes composed of α-KCr 1-xFexF 4 (x=0-0.13), which 

consists of one-dimensional Heisenberg antiferromagnets coexisting with geometrically 

frustrated spin systems with bond randomness. For x=0, an antiferromagnetic longrange 

order occurred at TN1 = 2.5(1) K and another phase transition occurred at TN 2 

= 4.0(1) K, because superexchange interactions through the three Cr-F-Cr paths in 

each non-equilateral triangle lost their equilibrium at low temperatures [1]. As a result, 

the values of spin-flop transition field drastically decreases with increasing x. This is 

probably due to the close correlation between the spin structure in the antiferromagnetic 

ordered state and the crystal structure as theoretically predicted by Nenert and Palstra, 

i.e., a magnetoelectric linear effect in which a magnetic field in an antiferromagnetic 

ordered state induces electrical polarization. Thus we carefully verified the crystal 

structure for x = 0-0.13. 

[1] H. Manaka et al., J. Phys. Soc. Jpn. 80, 084714 (2011). [2] G. Nenert and T. T. M. Palstra, J. 

Phys.: Condens. Matter 19, 406213 (2007). 


Poster Thursday


RI07 


A new approach to the characterization of aging, rejuvenation, and 

memory effects in magnetic systems 

Hiroaki Mamiya* and Shigeki Nimori 


We introduce a new approach to study non-equilibrium dynamics in magnetic systems. We 

found that simple ferromagnets such as pure terbium and nickel aluminide foils actually 

resembles typical spin glasses such as Cu 97Mn 3 and Cd 55Mn 45Te, in behavior of out-of-phase 

component of ac susceptibility and magnetic viscosity, when they are thermally perturbed 

after isothermal aging. Briefly, it is not enough to conventionally measure such dissipative 

properties for characterizing the non-equilibrium dynamics of these systems. In contrast, 

in the spin glasses, the relaxations of the uniform magnetization were accelerated at a 

constant magnetic field, when the spin glasses were cooled/heated after the isothermal aging. 

Surprisingly, such relaxations were reversed when they were subsequently reheated/recooled 

to the original temperature, despite the persistence of the magnetic field. Because the uniform 

magnetization mirrors the global evolution of the spin configuration, these reversions 

indicate that the spin configurations are spontaneously restored to the original [1,2]. On the 

other hand, such reversions were never observed in the ferromagnets. This fact indicates that 

ferromagnetic correlations are unaffected by the thermal perturbations, unlike rejuvenation in 

spin glasses. Thus, the observations of the uniform magnetization would be an additional key 

to clarifying the features of non-equilibrium dynamics in magnetic systems. 

[1] H. Mamiya and S. Nimori, New J. Phys. 12 (2010) 083007. [2] H. Mamiya and S. Nimori, J. 

Appl. Phys, in press. 

RI08 

The linear soliton generated by Z 2 vortex in quantum antiferromagnet 

Pawel Rusek 

Institute of Physics, Wroclaw University of Technology, PL, Poland 

The order parameter of noncollinear Heisenberg antiferromagnet is a triad of 

orthonormal vectors,i.e. the space of available states is isomorphic to SO 3 group. The 

topology of SO 3 manifold allows the existence Z 2 vortices in a system. We show that 

the anisotropy essentially changes the structure of Z 2 vortex in 2D spin system. On 

the scale larger than the scale la defined by weak anisotropy energy the Z 2 vortex is a 

termination of a linear soliton with the topological charge π1 (R) = Z 2 . In the soft core 

of this soliton the rotation angle of triad θ rapidly changes from the anisotropy locked 

value θa to θ = π, jumps on the line to θ = -π, and then decreases to the value θa on the 

la distance from the line. The linear soliton can terminate on the other Z 2 vortex or it 

should go out to surface sample. The rapid change of θ in the soft core of linear soliton 

causes the change of plaquette chirality there- the chirality change the sign on the line 

initiating the creation of the chirality domain. 

RI09 

Exact results of a mixed spin-1/2 and spin-1 Ising model with bilinear 

and three-site four-spin interactions on decorated planar lattices 

Michal Jascur 1 *, Viliam Stubna 1 , Karol Szalowski 2 and Tadeusz Balcerzak 2 

1 Institute of Physics, P.J. Safarik University in Kosice, Park Angelinum 9, 040 13 Kosice, Slovak 

2 Department of Solid State Physics, University of Lodz, ul. Pomorska 149/153, 90-236 Lodz, Poland 

A mixed spin-1/2 and spin-1 Ising model on decorated planar lattices is investigated 

using a generalized decoration-iteration transformation technique [1]. In addition to the 

standard bilinear nearest-neighbor interactions, we also consider three-site four-spin 

interactions and the crystal field effects. In this contribution, exact expressions for the 

partition function, critical temperatures and other thermodynamic quantities are obtained 

and analyzed. Performing numerical calculations, we have found that in addition to the 

standard ferromagnetic and paramagnetic phases there exists in the system also a peculiar 

partly ordered phase, which possesses non-zero entropy at T = 0 and appears only for zero 

bilinear exchange interaction. In this phase, the decorating atoms occupy spin states ±1 and 

0 with equal probability at all temperatures, while the nodal spins-1/2 are perfectly aligned 

along easy axis and generate non-zero magnetization. Our calculations primarily clarify 

the influence of many-body interactions in localized spin systems, which is apparently very 

different from the standard pair interactions due to the different symmetries of relevant 

terms in Hamiltonian. However, the presented results may be of wider interest since the 

origin of the three-site four-spin interaction is related to the magnetoelastic effect [2]. 

This work has been supported under grant VEGA No. 1/0234/12. [1] M. Jascur, Physica A 252 (1998) 

217. [2] T. Iwashita, N. Uryu, J. Phys. C: Solid State Phys. 17 (1984) 855. 


RI10 

Anomalous spin diffusion on the two-dimensional percolating network 

in Rb 2Mn 0.6Mg 0.4F 4 

Shinichi Itoh* 

Institute of Materials Structure Science, High Energy Accelerator Research 

Organization, Japan 

Inelastic neutron scattering experiments were performed on a two-dimensional dilute 

antiferromagnet, Rb 2Mn 0.6Mg 0.4F 4, with the magnetic concentration being close to the 

percolation concentration, c_p = 0.593, well above the Neel temperature, and with 

a high energy-resolution of ΔE = 17.5 μeV. The energy spectrum obtained from the 

observed dynamical structure factor S(q,E) integrated over wave number, q, throughout 

almost the entire Brillouin zone, showed a power law dependence, S(E) ~ E^{-x}. 

The diffusion on a percolating network is anomalous and it has been predicted that the 

mean square displacement of a random walker is described by ~ t^{2/(2+θ)} 

with an exponent, θ, as a function of the time, t. The exponent in S(E) is described as 

x = 1 - Df/(2+θ) with Df being the fractal dimension of the medium. The observed 

exponent, x, was in good agreement with a theoretical value. 

RI11 

Quantum phase transitions in 1/3 plateau of the quantum spin tube 

Kouichi Okunishi 1 *, Masahiro Sato 2 , Toru Sakai 3 , Kiyomi Okamoto 4 and Chigaku 

Itoi 5 

1 Department of Physics, Niigata University, Japan 

2 Department of Physics and Mathematics, Aoyama Gakuin University, Japan 

3 Japan Atomic Energy Agency, SPring-8 and University of Hyogo, Japan 


5 Department of Physics, Nihon University, Japan 

We study quantum phase transitions in the 1/3 plateau state of the three-leg spin-1/2 

tube, where the low-energy effective chirality degree of freedom plays an essential 

role. Using density matrix renormalization group and the effective chirality model, 

we find that the chirality liquid, a novel spin imbalance phase and the vector-spinchirality 

ordered phase emerge without closing the plateau spin gap, as the leg coupling 

increases. We also report the role of S_3-symmetry of the spin tube behind these 

quantum phase transitions in detail. 

K. Okunishi, M. Sato, T. Sakai, K. Okamoto and C. Itoi, arXiv:1109.0063 

RI12 

Cs 2CoC l4 - an effective XY-spin-½ compound in transverse magnetic 

fields 

Oliver Breunig 1 *, Eran Sela 2 , Benjamin Buldmann 2 , Markus Garst 2 , Petra Becker 3 , 

Ladislav Bohaty 3 , Ralf Muller 1 and Thomas Lorenz 1 

1 II. Physikalisches Institut, University of Cologne, Germany 

2 Institut fur Theoretische Physik, University of Cologne, Germany 

3 Institut fur Kristallographie, University of Cologne, Germany 

Cs 2CoCl 4 is a model system for studying the magnetism of one-dimensional spin 

chains with XY anisotropy. It contains CoCl 4 tetrahedra, which form one-dimensional 

chains along the crystallographic b-axis. The orbital groundstate of Co 2+ is split by 

the crystal field into doublets and an easy-plane anisotropy of the magnetization is 

established. The ground-state doublet is separated from the first excited doublet state 

by approximately 15 K, such that at temperatures between 0.3 and 4 K the compound 

is well described by the one-dimensional XXZ model. We compare experimental data 

of specific heat and thermal expansion to numerical calculations of the XXZ model 

for transverse magnetic fields; i.e., fields applied within the XY planes. Decreasing 

temperature below 0.3 K, magnetic order arises at field-dependent temperatures 

TC(H). Measuring thermodynamic properties with a magnetic field applied along the 

crystallographic b-axis, we observe a series of magnetic transitions within the ordered 

state. This work was supported by the DFG through SFB 608.

RI13 

Critical phenomena at the antiferromagnetic phase transition of 

Azurite Cu 3(CO 3)2(OH)2 

Pham Thanh Cong, Bernd Wolf*, Rudra Sekhar Manna, Andreas Bruhl, Sebastian 

Kohler and Michael Lang 


(M), Germany, Germany 

The natural mineral Azurite, Cu3(CO3)2(OH)2, has been considered as a model substance 

for the 1D distorted diamond chain, where unconventional magnetic properties result 

from the interplay of strong quantum fluctuations, low dimensionality and frustrating 

interactions. The system exhibits 3D long-range antiferromagnetic order at TN = 1.88 K. 

Our measurements of the sound velocity, ultrasonic attenuation and thermal expansion show 

pronounced signatures at TN indicating a strong coupling to the lattice degrees of freedom. 

We present a detailed investigation of the critical behavior of the sound velocity v22 and 

ultrasonic attenuation α in the vicinity of TN. Our analyses reveal a power-law behavior 

of the critical contributions v22cr ~ t-ζ and αcr ~ t-η over a decade of reduced temperature 

t = (T - TN)/TN both above and below TN. While the value of η = 1.21, obtained above 

TN, is close to the theoretical prediction for an anisotropy 3D Heisenberg antiferromagnet, 

the critical exponent derived from the sound velocity of ζ = 0.056, being identical for 

temperatures above and below TN, is at odds with this universality class. However, this value 

is consistent with the critical exponent observed in recent neutron scattering measurements [1]. 

[1] M. C. R. Gibbs et al., PRB 81, 140406(R), 2010 

RI14 

Dynamical Properties of Supersolid States in Spin Systems 

Yuta Murakami*, Takahi Oka and Hideo Aoki 

Physics, University of Tokyo, Japan 

It has been recognized that spin systems can be effectively thought of as boson models 

as in magnon BEC[1]. Specifically, a possibility to realize supersolid(SS) states (in 

the boson language) in spin systems is attracting recent attention, where a candidate is 

a frustrated spin-1/2 dimer model[2]. Here we study how the SS state accommodates 

collective excitations with the spin-wave theory. [3] We find that the excitation 

spectrum changes discontinuously as we go from a superfluid phase to an SS phase (that 

accompanies an SDW; CDW in boson language). Quantitatively, an analytic relation 

between the velocity of the Goldstone mode and the superfluid density is given. We 

also calculate the spin-spin correlation function, Szz(q, ω), which translates to the 

dynamical structure factor in cold-atom systems. We find the intensity of the mode as 

estimated from the peaks in Szz(q, ω) sharply blows up toward the boundary of SS, 

which is accompanied by a drastic change in the character of the roton mode. We also 

mention the possibility to enlarge the SS phase region. These results obtained in the 

effective boson model should also be directly applicable to cold bosonic atoms. 

[1] T. Giamarchi, C. Ru egg, and O. Tchernyshyov, Nat. Phys. 4, 198 (2008). [2] P. Chen, C. -Y. Lai, 

and M.-F. Yang, Phys. Rev. B(R) 81, 020409 (2010). [3]T. Sommer, M. Vojta, and K.W. Becker Eur. 

Phys. J. B 23, 329-339 (2001). 

RI15 

Magnetic phase transition of antiferromagnetic Cs 3V 2Cl 9 

Hikomisu Kikuchi 1 , Takashi Tanaka 1 , Yutaka Fujii 2 , Akira Matsuo 3 and Koichi Kindo 3 

1 Department of Applied Physics, University of Fukui, Japan 

2 Research Center for Development of Far-Infrared Region, University of Fukui, 

Japan 

3 ISSP, The University of Tokyo, Japan 

Cs3V2Cl9 belongs to the family of hexagonal compounds A3M2X9 (A=Cs, Rb, 

3- 

M=transition metal ions, X=Cl, Br) in which M2X9 dimers are oriented along 

crystallographic c-axis. Former work 1) on polycrystalline sample of Cs3V2Cl9 reported 

that intradimer interaction is ferromagnetic although ground state is nonmagnetic 

because of relatively large zero-field-splitting. Dimers of Cs3V2Cl9 form triangular 

lattice in their c-plane so that the geometrical spin frustration effect is expected to occur 

if interdimer interactions are antiferromagnetic. We measured magnetic susceptibility, 

specific heat, high field magnetization and 133 Cs-NMR using single crystal to study 

magnetic properties of Cs3V2Cl9. The specific heat shows two anomalies at around 15 

and 4 K suggesting successive phase transitions. Results will be discussed in terms of 

the spin frustration. 

1) B. Leuenberger et al. Inorg. Chem. 25, (1986) 2930. 

RI16 

RI17 

RI18 


Novel Field-Induced Quantum Phase Transition of the Kagome- 

Lattice Antiferromagnet 

Toru Sakai 1 * and Hiroki Nakano 2 

1 SPring-8, Japan Atomic Energy Agency, Japan 


The kagome-lattice antiferromagnet is investigated using the numerical exact diagonalization 

up to 42-spin clusters. From our investigation of the magnetization process, we found a 

novel field-induced quantum phase transition, called the ``magnetization ramp'', at 1/3 of 

the saturation magnetization [1]. The finite-size scaling analysis of the critical exponents[2] 

indicated a significant difference of the magnetization ramp from the magnetization plateau 

observed in the triangular-lattice antiferromagnet. The critical magnetization behavior at 

lower-field side of the magnetization ramp is same as that of the one-dimensional spin liquid. 

In order to clarify a difference between the magnetization ramp and plateau, we study a 

generalized anisotropic triangular-lattice model including the regular-triangular- and the 

kagome-lattice antiferromagnets in the parameter space. It revealed a quantum phase transition 

between the triangular- and kagome-lattices at 1/3 of the saturation magnetization. It means 

that the magnetization ramp of the kagome-lattice antiferromagnet is an essentially different 

phenomenon from the magnetization plateau of the triangular-lattice one. The relation to the 

recent magnetization measurements on the volborthite and vesignieite[3] is also considered. In 

addition we discuss about the spin gap issue of the kagome-lattice antiferromagnet [4]. 

[1]H. Nakano and T. Sakai: J. Phys. Soc. Jpn. 79 (2010) 053707. [2]T. Sakai and H. Nakano: Phys. Rev. B 83 (2011) 

100405(R). [3]Y. Okamoto, M. Tokunaga, H. Yoshida, A. Matsuo, K. Kindo and Z. Hiroi: Phys. Rev. B 83 (2011) 

180407(R). [4]H. Nakano and T. Sakai: J. Phys. Soc. Jpn. 80 (2011) 053704. 

Antiferromagnetic phase transition of K-Rb alloy nanoclusters 

incorporated in sodalite 

Takehito Nakano*, Yuko Ishida, Atsufumi Hanazawa and Yasuo Nozue 

Department of Physics, Graduate School of Science, Osaka University, Japan 

Aluminosilicate sodalite possesses a bcc arrangement of nanospaces (beta-cages). 

Alkali-metal nanocluster (A4)3+ can be formed in each beta-cage, where an s-electron 

is shared by four alkali cations. (Na4)3+ clusters in sodalite are known to show 

antiferromagnetism below the Neel temperature of 48 K [1]. By substituting heavier 

alkali atoms for Na ones, the Neel temperature systematically increases, namely, 72 K 

in (K4)3+ and 80 K in (K3Rb)3+ clusters [2]. In the present work, we have succeeded 

in preparing K-Rb alloy clusters with a higher Rb concentration, (K1.5Rb2.5)3+. 

Magnetic susceptibility obeys Curie-Weiss law and shows a peak at ~ 100 K. ESR 

spectrum is suddenly broaden below ~ 90 K to be an asymmetric shape which can 

be explained by powder pattern of antiferromagnetic resonance. These results clearly 

indicate that the present sample exhibits an antiferromagnetic phase transition at 

approximately 90 K which is higher than that in (K3Rb)3+. Substituting Rb for K 

makes the size of s-electron wave function of the cluster larger because of the larger ion 

size and the lower ionization energy of Rb. This reduces the U/t in the Mott-Hubbard 

insulating state resulting in an increase in the kinetic exchange coupling between the 

adjacent clusters. 

[1] V.I. Srdanov et al., Phys. Rev. Lett. 80, 2449 (1998). [2] T. Nakano et al., J. Phys. Soc. Jpn. 79, 

073707 (2010). 

A novel scaling method for critical phenomena studies: finite size 

effects 

Joao S Amaral 1 *, Jouke R Heringa 2 , Ekkes Bruck 2 and Vitor S Amaral 1 

1 CICECO and Dept. of Physics, Universidade de Aveiro, Portugal 

2 Delft University of Technology, Faculty of Applied Sciences, 2626 Delft, Netherlands 

We present a novel approach for critical phenomena studies. By quantifying scaling plot 

data overlap, we introduce a ‘goodness of scaling’ parameter, allowing an iterative search for 

the ‘best’ critical exponent values for a given set of magnetization data. The main advantage 

of this method is going beyond the usual power-law fits of the critical isotherm or low field 

susceptibility curve, by considering the complete equation of state and all data within the critical 

region. We consider Monte-Carlo simulated data of the 3D Ising model, and evaluate finitesize 

effects using our scaling method. Our results are in good agreement with the bibliography, 

including the dependence of pseudo-critical exponents on system size [1]. Interestingly, we 

have found that even with a strong dependence of these pseudo-critical exponents on system 

size, the equation of state is not affected by finite-size effects. The resulting scaling function is 

in good agreement with recent theoretical predictions for both exponent values and equation 

of state [2,3]. Our results suggest that while some effects may change the values of observed 

critical exponents of a given magnetic system, the state equation may retain its identity. In a 

sense, the state equation can be more universal than exponent values. 

[1] Haggkvist R., Rosengren A., Lundow P. H., Markstrom K., Andren D., Kundrotas P., Adv. Phys. 

56, 653-755 (2007). [2] Campostrini M., Pelissetto A., Rossi P., E. Vicari, Phys. Rev. E 65, 066127 

(2002). [3] D. O'Connor, J. A. Santiago, and C. R. Stephens, J. Phys. A 42, 045003 (2009). 


Poster Thursday


RI19 


The transverse-field quantum Ising model on infinite-dimensional 

structures using quantum Monte Carlo method and finite-size scaling 

Su Do Yi 1 , Seung Ki Baek 2 , Jaegon Um 2 and Beom Jun Kim 1 * 

1 1 

Department of Physics and BK2 Physics Research Division, Sungkyunkwan 

University, Suwon 440-746, Korea 

2 

School of Physics, Korea Institute of Advanced Study, Seoul 130-722, Korea 

In a number of classical statistical-physical models, there exists a characteristic 

dimensionality called the upper critical dimension above which one observes the meanfield 

critical behavior. Instead of constructing high-dimensional lattices, however, 

one can also consider infinite-dimensional structures, and the question is whether 

this mean-field character extends to quantum-mechanical cases as well. We therefore 

investigate the transverse-field quantum Ising model on the globally coupled network 

and on the Watts-Strogatz small-world network by means of quantum Monte Carlo 

simulations and the finite-size scaling analysis. We confirm that both of the structures 

exhibit critical behavior consistent with the mean-field description. In particular, 

we show that the existing cumulant method has difficulty in estimating the correct 

dynamic critical exponent and suggest that an order parameter based on the quantummechanical 

expectation value can be a practically useful numerical observable to 

determine critical behavior when there is no well-defined dimensionality. 

RI20 

Study of cluster heterogeneity scaling in the two-dimentional Ising 

model. 

Woo Seong Jo 1 , Su Do Yi 1 , Seung Ki Baek 2 and Beom Jun Kim 1 * 

1 

Department of Physics and BK21 Physics Research Division, Sungkyunkwan 

University, Suwon 440-746, Korea 

2 

School of Physics, Korea Institute of Advanced Study, Seoul 130-722, Korea 

The cluster heterogeneity, defined as the number of distinct cluster sizes, was suggested 

in [1] as an indicator of the phase transition in the percolation model. Noh et al. [2] 

found that the conventional finite-size scaling(FSS) form using the correlation-length 

exponent ν does not describe the scaling of the cluster heterogeneity in the percolation 

model and that the other exponent ν_H should be used instead. We apply the FSS form 

suggested in [2] for cluster heterogeneity in the Ising model. Since there are two types 

of clusters, (+) and (-) spin clusters, we calculate the heterogeneity of each type (H+ 

and H-, respectively), and carry out FSS near critical temperature. We find that total 

heterogeneity (H ≡ H+ + H-) scales with the exponent ν_H, as expected from [2] for 

the percolation model. 

[1] H.K. Lee, B.J. Kim, and H. Park, Phys. Rev. E 84, 020101(R) (2011). [2] J.D. Noh, H.K. Lee, 

and H. Park, Phys. Rev. E 84, 010101(R) (2011). 

RI21 

Zero-temperature phase transition in a one-dimensional Ising 

ferromagnet using Glauber dynamics with a synchronous update 

Il Gu Yi and Beom Jun Kim* 

Physics, Sungkyunkwan University, Korea 

Resently Glauber dynmaics for the one-dimensional Ising spin system at lowtemperature 

is studied variously not only experimentlly but also theoritically in the 

nano molecular system. Sznajd-Weron [Phys. Rev. E 82, 031120 (2010)] study the 

ferro anti-ferro phase transition of the density of active bonds, and the behavior 

of the relaxtion time which means the time needed to reach to steady state in the 

generalized zero temperature Glauber dynamcis. They suggested in that paper that the 

one-dimensional Ising model subject to the zero-temperature synchronous Glauber 

dynamics exhibits a discontinuous phase transition. We show here that the phase 

transition instead of a continuous nature, and we identify critical exponents, \beta 

\approx 0, \nu \approx 1, and z \approx 2 via a systematic finite-size scaling analysis. 

1. K. Sznajd-Weron, Phys. Rev. E 82, 031120 (2010). 2. N. Goldenfeld, Lectures on Phase 

Transitions and the Renormalization Group (Addison-Wesley, Boston, 1992). 


RI22 

Stochastic treatment of magnetic moment relaxation in spin echo 

models 

Maxim Pavlovich Shlykov 

National Research Centre 'Kurchatov Institute', Russia 

The method of nuclear spin-echo amplitude calculation based on the density matrix technique is 

improved. Spin echo model [1] was supplemented with stochastic consideration of the magnetic 

moment relaxation provided by the interaction nuclear spin with fluctuating magnetic field. The 

theory of reducible systems [2] was applied for solving stochastic differential equations. This 

mathematical approach was adapted to find the solution of the Schrodinger equation for the timeevolution 

operator which describes behavior of a nuclear spin in the presence of a radiofrequency 

pulsed magnetic field and fluctuating magnetic field. NMR spin echo for I = 1/2 is considered as 

the simplest illustration of the method. Unlike classical approaches [3,4], It allows to calculate 

spin-echo amplitude correctly over whole period of relaxation without any estimates. The 

possibility of application of well-known Ito calculus [5] is also discussed. It was obtained more 

accurate formulae for spin-lattice relaxation time T1 and spin-spin relaxation time T2 . 

[1] Kravchenko E. A., Orlov V. G., Shlykov M. P., Magnetic properties of bismuth(III) oxy 

compounds, Russian Chemical Reviews, 2006, 75 (1), 77-93 [2] Erougin N., Reducible systems, 

Travaux Inst. Math. Stekloff, 1946, 13, 3-96 [3] Redfield A.G., On The Theory of Relaxation 

Processes, IBM Journ. Res. Develop., 1957, 1, 19-31 [4] Bloembergen N., Purcell E. M., Pound R.V., 

Relaxation Effects in Nuclear Magnetic Resonance Absorption, Phys. Rev., 1948, 73, 679-712 [5] 

Gardiner, C. W., Handbook of stochastic methods for physics, chemistry and the natural sciences, 

Springer, 1994, 13, 442 

RJ01 

Vortex core switching on notched circular disks 

Tomonori Sato* and Yoshinobu Nakatani 

University of Electro-Communications, Japan 

The vortex core manipulation by field has been frequently reported. However, the 

minimization of switching field is still being debated. In general, the vortex core 

switching is performed by annihilation of vortex and anti-vortex, however the 

nucleation of the pair requires large magnetic field. In this report, we proposed the 

new switching mechanism to decrease switching field by using circular disks with 

V-shaped notch. When the in-plane pulse field is applied, the vortex core moves to the 

notch and annihilates automatically. After the field is switched off, the vortex core gets 

back by demagnetizing field. The vortex core polarity is controlled by the external field 

perpendicular to the disk. In this switching mechanism, the vortex core switching is 

performed by only the annihilation and nucleation of the vortex, therefore the switching 

field is decreased compared with the circular disks without notch. We investigated the 

vortex core switching by micromagnetic simulation. A Permalloy disk with 200nm 

diameter and 40nm thickness is used in the simulation. The field perpendicular to the 

disk was fixed at 50 Oe. The result reveals that the minimum switching field decreases 

60% compared with the case using the circular disk without notch. 

RJ02 

Effect of oersted field on magnetic vortex core gyration 

Tomonori Sato 1 *, Yoshinobu Nakatani 1 and Teruo Ono 2 

1 University of Electro-Communications, Japan 

2 Kyoto University, Japan 

Recently, the vortex core manipulations by spin current are studied intensively. 

Because spin current creates the Oersted field, there are some reports, which study 

the effect of the field on the vortex core motion. When the vortex core is manipulated 

by the current, the electrodes are usually attached on top of the disk. Therefore, the 

current goes in and out from the top surface of the disk mainly. It makes the current 

non-uniform, and it makes the Oersted field complex. In this work, we report the effect 

of the Oersted field and the current distribution on the vortex core gyration by AC 

current by micromagnetic simulation. A Permalloy circular disk with 1.5μm diameter 

and 40nm thickness is used in the simulation. The AC current density is 2.66x1011A/ 

m2 mainly. The current frequency is varied around the resonant frequency of the 

disk. The result reveals that the effect of the Oerstead field changes by the current 

density, however the percentage of the effect of the Oersted field on the driving force 

is 8% in maximum. Furthermore, the vortex core is affected by not only the in-plane 

components but also the out-of-plane component.

RJ03 

Mutual spin-transfer torque in vortex nano-oscillators 

Xiaolei Wang, Ning Wang and Antonio Ruotolo 

Department of Physics and Materials Science, City University of Hong Kong, Hong 

Kong 

We studied the emission response of spin transfer vortex oscillators with dynamic 

polarizer. In these systems, mutual spin transfer torque between the two ferromagnetic 

layers is at the origin of a very rich dynamics. By changing the injected current, we 

could gain access to up to three dynamic modes. At high currents, mutual spin transfer 

torque is at play and high-frequency dynamics is simultaneously excited in both layers. 

The detected mode corresponds to a Slonckzewski’s windmill-like mode, which is 

stable in a large range of experimental conditions. The mode observed at low currents 

corresponds to the commonly observed dynamics in nano-contact vortex oscillators, in 

which the vortex core is far away from the contact and current-in-plane spin-transfer 

torque is at play. Surprisingly, we could gain access to a third mode at intermediate 

currents, which we ascribe to the precession of a vortex in the thin ferromagnetic layer 

under the contact area. This mode is of particular scientific interest because it allows 

one to experimentally study the vortex dynamics in the small amplitude limit. 

RJ04 

Key role of temperature in ferromagnetic bloch point simulations 

Kristof M. Lebecki 1 *, Denise Hinzke 1 , Oksana Chubykalo-fesenko 2 and Ulrich 

Nowak 1 

1 Department of Physics, University of Konstanz, Germany 

2 Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, 

Spain 

A Bloch point (BP) is known to play a crucial role during vortex core switching process [1]. 

Vortices themselves attract recently much attention since it was suggested to use them as a 

magnetic storage medium. For such an application BP-related vortex core properties like the 

switching speed or stability of the final state are essential. This makes the BP an important 

object of study. We present here results of numerical simulations, where the BP at elevated 

temperature is investigated. Our approach makes it possible to model its behavior without 

problems related to its singular character [1,2] - as opposed to all BP simulations presented 

in the literature so far. We have included temperature effects via Landau-Lifshitz-Bloch 

equation [3]. Our implementation, basing on the OOMMF code, allow us to compare results 

of analytical theories with modern numerical approach. We focus our attention on permalloy 

and conduct studies in the full temperature range. Firstly, we will present results of modeling 

an artificially pinned BP. This reveals details of its geometry, including its temperaturedependent 

radius. Secondly, we will present results of dynamical studies, where the vortex 

core switches via nucleation, propagation and annihilation of a BP. 

1. S. Gliga, Y. Liu, and R. Hertel, J. Phys.: Conf. Ser., 303, 012005 (2011). 2. A. Thiaville, J. M. Garcia, R. 

Dittrich, J. Miltat, and T. Schrefl, Phys. Rev. B 67, 094410 (2003). 3. D. A. Garanin, Phys. Rev. B 55, 3050 (1997). 

RJ05 

Polarization-selective signal propagation in a chain of vortices 

Andreas Vogel 1 *, Michael Martens 1 , Markus Weigand 2 and Guido Meier 1 

1 

Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, 

Universitaet Hamburg, Germany 

2 

Max-Planck-Institut fuer Intelligente Systeme, Germany 

Dynamics on the subnanosecond time scale and potential technological applications give rise to 

a broad scientific interest in the dynamic properties of ferromagnetic microstructures with vortex 

magnetization configuration. An excitation of the low frequency mode of gyration can be transferred 

via dipolar interaction between neighboring ferromagnetic elements with the transfer efficiency 

strongly depending on their separation and the relative configuration of the vortex-core polarizations [1]. 

The dependence on the core polarizations can be understood considering the time-dependent shape 

of the external stay field. We employ time-resolved scanning transmission x-ray microscopy to study 

the vortex-core dynamics in a chain of three stray-field coupled permalloy squares. After exciting the 

first element via a short in-plane magnetic field pulse, the excitation can be transferred through the 

chain. No response is observed in the third square for equal core polarizations of all elements but the 

excitation can be transferred through the chain just by changing the polarization in the central element. 

For alternating polarizations, a transfer efficiency of about 56% to the third square is achieved. The 

chain can be switched back and forth between the transmitting and a locking state [2]. 

[1] A. Vogel, T. Kamionka, M. Martens, A. Drews, K. W. Chou, T. Tyliszczak, H. Stoll, B. Van 

Waeyenberge, and G. Meier, Phys. Rev. Lett. 106, 137201 (2011); H. Jung, K.-S. Lee, D.-E. Jeong, Y.-S. 

Choi, Y.-S. Yu, D.-S. Han, A. Vogel, L. Bocklage, G. Meier, M.-Y. Im, P. Fischer, and S.-K. Kim, Sci. Rep. 1, 

59 (2011). [2] A. Vogel, M. Martens, M. Weigand, and G. Meier, Appl. Phys. Lett. 99, 042506 (2011). 

RJ06 

RJ07 

RJ08 


Theoretical study on frequency of vortex-antivortex pairs rotation in a 

magnetic thin-film with multi-contacts 

Hiroshi Tsukahara, Hiroko Arai and Hiorshi Imamura* 

AIST, Japan 

Spin transfer torque (SST) induced magnetization dynamics is one of the key concepts 

in spintronics and intensive studies have been conducted in the last two decades to 

realize STT based memories (Spin-RAM) and microwave oscillators. Finocchio et 

al. studied the STT induced magnetization dynamics in magnetic thin-film nanopillar 

which has one aperture and found that the rotational dynamics of a vortex-antivortex 

(VA) pair produces the resistance oscillation [1]. Therefore, it is interesting to study 

how the VA-pair dynamics in a multi-contacts system is influenced by the distance 

between contacts. We performed micromagnetic simulations of a magnetic thin-film 

where the spatially localized spin-polarized current was injected through two nanocontacts 

and found the rotation of VA pairs. If the distance between two contacts is 

so large that the VA pair cannot interfere with each other, they independently rotate 

around each contact. In contrast, when the distance becomes small, the single VA pair 

rotates around a large area in which the two contacts are included and the rotation 

frequency drops down to about 60% of that of a single contact. Our results show that 

we can control the frequency of the VA pair rotation by changing the distance between 

the contacts. 

[1] G. Finocchio, O. Ozatay, L. Torres, R. A. Buhrman, D. C. Ralph and B. Azzerboni, Phys. Rev. B 

78 174408 (2008) 

Parametric excitation and subcritical phase-locking in spin-transfer 

vortex oscillators 

Paolo Bortolotti 1 *, C. Serpico 2 , E. Grimaldi 1 , J. Grollier 1 , V. Cros 1 , A. Fukushima 3 , H. 

Kubota 3 , K. Yakushiji 3 , S. Yuasa 3 , K. Ando 3 and A. Fert 1 

1 Unite Mixte de Physique CNRS/Thales, France 

2 Dipartimento di Ingegneria Elettrica,Universita di Napoli 'Federico II', Italy 


In the last decade several systems have been proposed to design low power consuming nano-oscillators. 

One promising example is a MgO tunnel junction with a vortex free layer[1,2] (STVO). Classically, 

oscillations at its natural frequency f_0 are obtained for currents larger than a critical value Ic. However, by 

applying a rf-excitation current at 2f_0, i.e., parametric excitation[3,4], it is possible to force the system into 

oscillation even in the subcritical current regime (I


RJ09 


Stability of the vortex structure on the core switching by AC current 

Tomonori Sato* and Yoshinobu Nakatani 

University of Electro-Communications, Japan 

Recently, magnetic disks with a vortex core have been considered as one of the 

candidates for the storage devices, and many reports relating to the core switching by 

spin current have been reported. Because the storage capacity depends on the magnetic 

disk size, it is important to investigate the stability of the vortex structure on its size. 

Until now, the disk size that the core can switch stable has not been reported. In this 

work, we investigate the stability on the core switching by micromagnetic simulation. 

In the simulation, two methods are used, the method by the core switching simulation 

by AC spin current and the method by the evaluation of the magnetic energy. The 

switching simulation reveals that the core does not switch around the transition 

dimension of magnetic disks between single-domain structure and the vortex structure 

on a remanent state, and the disk diameter needs to be increased about 20 to 80 nm 

for the stable core switching compared with the stability limit on the remanent state. 

Furthermore, the result of the energy evaluation agreed with the result obtained by the 

switching simulation. Therefore, the stability on the core switching can be estimated by 

the magnetic energy. 

RJ10 

Time-averaged observation of magnetic vortex resonated in squareshaped 

NiFe films 

Motoi Kodama 1 , Koji Sekiguchi 2 and Yukio Nozaki 3 * 


2 Department of Physics, Keio University, JST PRESTO, Japan 

3 Department of Physics, Keio University, JST CREST, Japan 

A dynamics of magnetic vortex confined in a patterned ferromagnetic thin film attracts 

much attention for both the fundamental and the technological points of view. The 

observation of the trajectory of magnetic vortex core excited with an application of 

ac magnetic field or ac current is significant for the quantitative understanding of spin 

dynamics. In this study, a time-averaged observation of magnetic vortex resonated 

in square-shaped NiFe thin film was demonstrated by means of magnetic force 

microscopy (MFM) to obtain the trajectory. A 30 nm-thick NiFe film with the lateral 

size of 1x1um 2 was fabricated on a coplanar waveguide that generates an ac magnetic 

field of 1mT in amplitude. The resonant frequency of the magnetic vortex formed in the 

NiFe film was calculated to 260 MHz that is much higher than the sampling frequency 

of MFM. When the ac magnetic field with a frequency of 260 MHz was applied, a 

circular pattern with a uniform magnetic contrast appeared in the vicinity of center of 

the NiFe film. The diameter of the circle is comparable with that of the trajectory of 

magnetic vortex core calculated with micromagnetic simulation. 

RJ11 

Diverging-converging spin vortex pairs in biquadratically interlayer 

exchange coupled elements 

Sebastian Wintz 1 *, Christopher Bunce 1 , Anja Banholzer 1 , Michael Koerner 1 , Sibylle 

Gemming 1 , Artur Erbe 1 , Joerg Raabe 2 , Christoph Quitmann 2 and Juergen Fassbender1 

1 Helmholtz-Zentrum Dresden-Rossendorf, Germany 

2 SLS, Paul Scherrer Institut, Switzerland 

Spin structures have been an interesting topic of magnetism research for many years. 

Within this field, magnetic vortices have attracted much attention, due to their nontrivial 

topology and the various dynamic modes they exhibit [1]. A magnetic vortex 

consists of a planar, flux-closing magnetization curl that turns out of the plane in the 

central nanoscopic core region. In a single layer structure, the curl’s radial components 

typically cancel each other out. Recent investigations show that this also holds true 

for multilayer vortex systems with bilinear interlayer exchange coupling [2]. Here 

we report on pairs of diverging-converging spin vortices occurring in biquadratically 

coupled systems. Using magnetic scanning transmission x-ray microscopy (STXM) 

we directly observe that the individual vortices of such pairs possess a residual radial 

magnetization component, i.e. ∇Mxy≠0. This implies an additional perpendicular 

magnetization divergence ∇Mz, for which we compare a continuous model with 

discrete micromagnetic simulations. 

[1] S.-B. Choe et al., Science 304, 420 (2004). [2] S. Wintz et al., Appl. Phys. Lett. 98, 232511 (2011). 


RJ12 

Magnetic vortex dynamics in exchange-biased micron-sized structures 

Sofia De Oliveira Parreiras 1 *, Flavio Garcia 2 and Maximiliano Delany Martins 1 

1 Applied Physics Laboratory, CDTN/CNEN, Brazil 

2 Laboratorio Nacional de Luz Sincrotron, Brazil 

The study of magnetic dots with magnetic vortex spin configuration has recently 

attracted great scientific interest [1]. The great potential of applications of magnetic 

vortices (as for example magnetic memories and nanoparticles for cancer treatment) 

draws attention for the investigation of vortex proprieties. In this work, we studied the 

dynamics proprieties of exchange-biased vortex using the code OOMMF (NIST) [2] 

that applies the Landau-Lifshitz-Gilbert equation to simulate the spin configuration and 

compute the energy and magnetization of microstructures. A series of micromagnetic 

simulations for Permalloy/Fe 50Mn 50 disks with 0.5 ?m of diameter was done varying 

the magnetic coupling constant between the layers. We had observed that the vortex 

gyrotropic movement has a variable frequency that increases with the time, which is 

not observed when exchange bias is absent. Under a rotating magnetic field acting in 

the disks, the critical velocity for vortex polarity reversion increases with the coupling 

constant and frequency. Our results show that the critical velocity can be adjusted in a 

wide range by selecting the magnetic coupling constant and the oscillating frequency, 

i.e., it is possible to control the critical velocity for vortex polarity inversion through 

the exchange bias coupling. 

[1] C. L. Chien, F. Q. Zhu, and J.-G. Zhu, Physics Today 60, 40 (June, 2007) [2] M. J. Donahue and 

D. G. Porter, http://math.nist.gov/oommf/ 

RJ13 

Magnetic Vortex Echo 

Flavio Garcia1*, Joao Paulo Sinnecker2, Erico Novais2 and Alberto Passos 

Guimaraes2 

1 Brazilian Sinchrotron Light Laboratory, Brazil 


The interest of magnetic vortices has greatly grown in the last years since these systems 

present a myriad of promising applications, which are mainly related on their dynamics 

aspects. When the vortex core is excited from its equilibrium position, it relaxes in 

a spiral motion, with a very well defined frequency, which is inversely proportional 

to the disk aspect ratio. The sense of the gyrotropic motion is determined by the core 

polarity. So, controlling the polarity, it is easy to control the sense of gyrotropic motion. 

In this work, we analytically shown that, properly manipulating the dynamic properties 

of the vortex, namely its polarity, in an analogous way as it is done in Nuclear 

Magnetic Resonance, it is possible to generate a magnetic vortex echo (MVE). This 

echo is similar to the spin echo, and it may provide fundamental information about the 

dynamic properties of real arrays of vortices, e.g., magnetic coupling, inhomogeneities, 

magnetic stability etc. To illustrate the MVE, we performed micromagnetic simulation 

of arrays of nanodisks, where it has been varying their most significant parameters to 

prove that the MVE can give significant information about the dynamic properties of 

the real array of disks. 

ArXiv:1201.3553 

RJ14 

Origin of the dipolar coupling between vortex-state disks 

Ki-suk Lee and Sang-koog Kim* 

Seoul National University, Korea 

Coupled vortex gyrations in spatially separated nanodisks have been studied theoretically[1,2], 

experimentally[3-8], and numerically[9] owing to their possible applications as an alternative to current 

signal processing devices with the advantage of negligible energy loss[7]. Fundamental phenomena 

such as eigenfrequency splitting and its dependence on dot-to-dot interdistance[3,4,7] have been verified 

experimentally and explained well by the normal mode representation[7,9]. In this work, we studied dynamic 

dipole interaction of coupled vortex gyrations observed in two disks by micromagnetic simulation and 

analytical approaches. Shibata et al.[1] reported that, based on rigid vortex model [10], the dynamic dipolar 

interaction of the coupled vortex gyrations originates from the magnetostatic interaction that is induced by the 

side surface charges of each disk during the gyrations [1,2]. We extracted the interaction energies of the two 

dipolar-coupled disks and compared those that are obtained directly from the micromagnetic simulations and 

obtained from spin configurations based on two different side-charge-free[10] and rigid-vortex models. The 

simulation result is in better agreement with the side-charge-free-model-based spin configurations than the 

rigid-vortex-model one. These results imply that the dipolar energy of the coupled gyrations of neighboring 

vortex-state disks originates dominantly from not the side surface charges of each disk, but the volume charges. 

This work was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded 

by the Ministry of Education, Science and Technology(No. 20110000441). [1] J. Shibata et al.,Phys. Rev.B 67,224404(2003). 

[2] O.V. Sukhostavets, et al.,Appl. Phys. Express 4,065003(2011). [3] A. Vogel et al.,Phys. Rev. Lett.105,037201(2010). [4] S. 

Sugimoto et al.,Phys. Rev. Lett.106,197203(2011). [5] A. Barman et al.,J. Phys. D.43,422001(2010). [6] H. Jung et al.,Appl. 

Phys. Lett.97,222502(2010). [7] H. Jung et al.,Sci. Rep. 1,59;DOI:10.1038/srep00059(2011). [8] A. Vogel et al.,Phys. Rev. 

Lett.106,137201(2011). [9] K.-S. Lee et al.,J. Appl. Phys.110,113903(2011). [10] K. Y. Guslienko et al.,J. Appl. Phys.91,8037(2002).

RJ15 

Switching dynamics of vortex cores in nanodots by azimuthal-spinwave-mode 

excitation 

Myoung-woo Yoo, Jehyun Lee and Sang-koog Kim* 

National Creative Research Initiative Center for Spin Dynamics & Spin-Wave Devices & Nanospinics 

Lab, Research Institute of Adv. Materials, Dep. of Materials Sci. & Eng., Seoul Nat'l Univ., Seoul, Korea 

Owing to a possibility of implementations of magnetic vortices in future information-storage devices, 

vortex-core reversals have attracted much attention [1]. Very recently, ultrafast, low-power-driven core 

switching by azimuthal spin-wave mode was experimentally demonstrated [2]. Since their quantitative 

interpretation and deeper understanding remain elusive, we start to elucidate the underlying physics of the 

switching dynamics. In this study, we performed micromagnetic simulations on a Permalloy disk of 302 

nm diameter and 50 nm thickness. We correlate the critical velocities (vc) and gyrofields (hz,cri) to the core 

switching driven resonantly by azimuthal mode excitations. For given disk’s dimensions and geometry 

used here, the vc increases to ~400 and ~700 m/s for m = -1 (clockwise) and +1 (counter-clockwise) 

modes, respectively, although vc is known to be ~330 m/s for the gyration-mode-assisted-core-switching 

mechanism [3]. This difference originates from the difference of hz,cri between the gyration mode and 

azimuthal mode driven core switching mechanisms because the magnetization dip of mz = -1 is necessary 

for the switching. From our calculations, hz,cri are estimated to be ~7 kOe and ~11 kOe for CW and CCW 

azimuthal mode excitations, compared to the value of hz,cri = 3.3 kOe for the gyration mode excitation [4]. 

*Corresponding author: sangkoog@snu.ac.kr [1] B. Van Waeyenberge et al., Nature (London) 444, 461 (2006); 

S. -K. Kim et al., Appl. Phys. Lett. 92, 022509 (2008). [2] M. Kammerer et al., Nat. Commn. 2:279 doi: 10.1038/ 

ncomms1277 (2011). [3] K.-S. Lee et al., Phys. Rev. Lett., 101, 267206 (2008). [4] M.-W. Yoo et al., Phys. Rev. B, 82, 

174437 (2010). [5] This work was supported by the Basic Science Research Program through the National Research 

Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (No. 20110000441). 

RJ16 

Logic operations based on magnetic-vortex-state networks 

Hyunsung Jung 1 , Youn-seok Choi 1 , Dong-soo Han 1 , Young-sang Yu 1 , Ki-suk Lee 1 , 

Mi-young Im 2 , Peter Fischer 2 and Sang-koog Kim 1 * 

1 National Creative Research Initiative Center for Spin Dynamics & Spin-Wave 

Devices & Nanospinics Lab, Research Institute of Adv. Materials, Dep. of Materials 

Sci. & Eng., Seoul Nat'l Univ., Seoul, Korea 

2 Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA 

94720, USA 

Logic operations based on coupled magnetic vortices were experimentally demonstrated. We utilized a 

simple chain structure consisting of three physically separated but dipolar-coupled vortex-state Permalloy 

disks as well as two electrodes for application of the logical inputs. We directly monitored the vortex 

gyrations in the middle disk, as the logical output, by time-resolved full-field soft X-ray microscopy 

measurements. By manipulating the relative polarization configurations of both end disks, two different 

logic operations are programmable: the XOR operation for the parallel polarization, and the OR operation 

for the antiparallel polarization. This work paves the way for new-type programmable logic gates based 

on the coupled vortex-gyration dynamics achievable in vortex-state networks. The advantages are as 

follows: a low-power input signal by means of resonant vortex excitation, low-energy dissipation during 

signal transportation by selection of low-damping materials, and a simple patterned-array structure. 

*Corresponding author: sangkoog@snu.ac.kr This research was supported by the Basic Science Research Program through 

the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science, and Technology (grant 

no. 20110000441). The operation of the microscope was supported by the Director, Office of Science, Office of Basic Energy 

Sciences, Materials Sciences and Engineering Division, U.S. Department of Energy, under contract no. DE-AC02-05-CH11231. 

RJ17 

Vortex-gyration-mediated magnonic crystals 

Dong-soo Han and Sang-koog Kim* 

National Creative Research Initiative Center for Spin Dynamics & Spin-Wave Devices 

& Nanospinics Lab, Research Institute of Adv. Materials, Dep. of Materials Sci. & 

Eng., Seoul Nat'l Univ., Seoul, Korea 

Recently, mutual energy transfer between spatially separated magnetic disks has been studied and interpreted 

based on a coupled-vortex-oscillator model [1-5]. This novel energy-transfer mechanism provides the 

advantages of tunable energy transfer rate, low-power input signal, and extremely low energy dissipation 

for the case of using negligible damping materials. Here, we extended this study into magnonic crystals of 

one-dimensional (1D) and 2D arrays of dipolar-coupled magnetic disks. We analytically and numerically 

explored the fundamental modes of collective vortex-gyration excitations in such 1D and 2D disk-array 

magnonic crystals of four different ordering of vortex polarization (p) and chirality (C) states. Both the 

analytical and numerical calculations show excellent quantitative agreement on contrasting dispersion 

branches for different orderings of p and C states. Such collective vortex-gyration modes can be understood 

in terms of the energy variation of dynamic dipolar interaction between the neighboring vortex-state disks. 

These results provide for the possibility of vortex-gyration-mediated magnonic crystals as applications for 

future signal processing devices, offering the advantages of low energy dissipation and low power input. 

This work was supported by Basic Science Research Program through the National Research Foundation of 

Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 20110000441). 

*Corresponding author: sangkoog@snu.ac.kr [1] J. Shibata et al., Phys. Rev. B 67, 224404 (2003). [2] J. 

Shibata et al., Phys. Rev. B 70, 012404 (2004) [3] S. Barman et al., IEEE Trans. Mag. 46, 1342 (2010) [4] H. 

Jung et al., Appl. Phys. Lett. 97, 222502 (2010); H. Jung et al., Sci. Rep. 1, 59 ; DOI:10.1038/srep00059 (2011); 

A. Vogel et al. Phys. Rev. Lett. 106, 137201 (2011); S. Sugimoto et al. Phys. Rev. Lett. 106, 197203 (2011). [5] 

K.-S. Lee et al., J. Appl. Phys. 110, 113903 (2011); O.V. Sukhostavets, Appl. Phys. Express 4, 065003 (2011). 

RJ18 

RJ19 

RJ20 


Vortex-gyration transfer rate and energy attenuation in coupled 

nanodisks 

Ji-hye Kim, Ki-suk Lee, Hyunsung Jung, Dong-soo Han and Sang-koog Kim* 




One of the most important research goals in current information-signal processing technologies is to enhance 

signal-processing speed and to reduce energy loss[1]. In recent electronic devices, information-signal transports 

are based on the motion of electron charges. Interestingly, coupled vortex oscillations in nanodots can be used 

as an alternative mechanism of information-signal processing[2-4]. Here, we report a study of, by analytical 

and micromagnetic numerical calculations, information-signal transfer in vortex-state nanodisks that is 

available with assistance of vortex-gyration transfer through the dynamic dipolar interaction. We analytically 

derived the vortex-gyration transfer rate and energy attenuation that are both technologically essential 

parameters for controlling signal processing speed and energy loss in signal processing devices. It is found that 

the transfer rate can be controlled by the relative polarization configuration p1p2, the saturation magnetization 

Ms, and the radius (R)-to-thickness (L) ratio R/L of given magnetic disks as well as interdistance. The energy 

attenuation is governed by not only the intrinsic damping constant of a given material, but also the values of 

Ms, L, and R. The analytical results are in reasonable agreements with micromagnetic simulation results. This 

work provides a foundation of manipulating information-signal processing between vortex-state networks. 

* Corresponding author : sangkoog@snu.ac.kr. [1] K. Bernstein et al., Proc. IEEE 98, 2169 (2010). [2] H. Jung et al., Appl. Phys. 

Lett. 97, 222502 (2010). [3] H. Jung et al., Sci. Rep. 1, 59; DOI:10.1038/srep00059 (2011). [4] S. Barman et al., IEEE Trans. Magn. 

46, 1342 (2010). [5] A. Vogel et al., Phys. Rev. Lett. 106, 137201 (2011). [6] This work was supported by the Basic Science Research 

Program through the NRF of Korea funded by the Ministry of Education, Science and Technology (Grant No. 20110000441). 

Effect of spin-motive force and spin-diffusion on a vortex dynamics 

Jung-hwan Moon 1 , Aurelien Manchon 2 and Kyung-jin Lee 1 * 

1 

Department of Materials Science and Engineering, Korea University, Seoul 136- 


2 

Materials Science and Engineering, Division of Physical Science and Engineering, 

KAUST, Thuwal 23955, Saudi Arabia, Saudi Arabia 

Theoretically, it is known that the dynamics of magnetic texture highly depends on 

damping (α) and non-adiabatic parameter (β). However, the value of β is controversial 

both theoretically and experimentally. Moreover, it was recently reported that α and β are 

also affected by the spin configuration. The former comes from spin-motive force(SMF) 

[1, 2] and the latter comes from torque which is exerted from spin-diffusion [3]. In order 

to understand the spin dynamics under complex spin texture, it is needed to study the 

effect of SMF and spin-diffusion on α and β. In this work, we performed micromagnetic 

simulation using LLG equation with spin torque term, SMF, and spin-diffusion. The currentinduced 

dynamics of a vortex core is micromagnetically modeled using a computational 

framework based on the fourth-order Runge-Kutta method. The model system is a circular 

Permalloy disk with the thickness of 20 nm and the diameter of 270 nm which is vortex 

favored dimension. Initial trajectory with spin-diffusion was shifted along y-axis direction 

compared to that without spin-diffusion. It is because that the initial motion of a core motion 

is governed by non-adiabaticity [4]. The further studies will be discussed in detail. 

[1] S. Zhang and S.-L. Zhang, Phys. Rev. Lett. 102, 086601 (2009). [2] J.-H. Moon, S,-M. Seo, and K.-J. Lee, IEEE Trans. Magn., 

vol. 46, p.2167 (2010) [3] A. Manchon, W.-S. Kim, and K.-J. Lee, unpublished. [4] J.-H. Moon et al., Phys. Rev. B 79, 134410 (2009). 

Soft X-ray microscopy of non-linear magnetic vortex core motion 

Peter Fischer 1 , Brooke Mesler 1 , Mi-young Im 1 and Kristen Buchanan 2 

1 CXRO, LBNL, USA 

2 Colorado State U, USA 

Magnetism on the nanometer length scale and its fast spin dynamics is a scientfically 

highly attractive and technologically relevant topic. It addresses fundamental magnetic 

length scales e.g. magnetic exchange lengths in the sub-10nm range and fast time 

scales in the sub-ns regime where precessional and relaxation phenomena, domain 

wall motion and vortex dynamics occur [1,2]. New technological concepts such as 

spintronics require precise control the electron spin on a nanoscale with psec timing. 

We use time magnetic soft X-ray microscopy providing a spatial resolution down 

to 10nm and a temporal resolution below 100ps [3]. As one example, we report 

experimental results showing non-linear behavior in the resonant excitation of 

magnetic vortex cores with increasing amplitude of the exciting magnetic AC fields 

[4]. Supported by the Director, Office of Science, Office of Basic Energy Sciences, 

Materials Sciences and Engineering Division, of the U.S. Department of Energy. 

[1] L. Bocklage, et al. Phys Rev B 81, 054404 (2010) [2] S. Kasai, et al Phys Rev Lett 101, 237203 

(2008) [3] P. Fischer, Materials Today 13(9) 14 (2010) [4] B. Mesler et al J.Appl. Phys. (2012) in 

print 


Poster Thursday



RK01 

Dynamics of Successive Minor Hysteresis Loops 

Alexander Gerber and Yoav W Windsor 

School of Physics and Astronomy, Tel Aviv University, Israel 

Cumulative growth of successive minor hysteresis loops in Co/Pd multilayers with 

perpendicular anisotropy was studied in the context of time dependent magnetization 

reversal dynamics. We show that in disordered ferromagnets, where magnetization 

reversal involves nucleation, domains’ expansion and annihilation, differences between 

the time dependencies of these processes are responsible for accumulation of nuclei for 

rapid domain expansion, for the asymmetry of forward and backward magnetization 

reversals and for the respective cumulative growth of hysteresis loops. Loops stop 

changing and become macroscopically reproducible when populations of upward 

and downward nucleation domains balance each other and the respective upward and 

downward reversal times stabilize. 

RK02 

Gilbert damping constants of exchange biased NiFe/FeMn bilayers 

Jungbum Yoon, Hyeok-cheol Choi and Chun-yeol You* 

Department of Physics, Inha Universirty, Korea 

The physics of exchange bias effect has been studied intensively for the past decades, 

however, a few experiments have been reported about the spin dynamics and damping 

mechanism for the exchange biased systems. Recently, the vector network analyzer 

ferromagnetic resonance (VNA-FMR) is employed to research the spin dynamics of 

ferromagnetic thin films with wide range microwave frequencies. In this study, the 

dynamics magnetic properties of the NiFe/FeMn bilayers is investigated by VNA-FMR 

with various external static field. The exchange bias is verified by vibrating sample 

magnetometer and VNA-FMR with varying the thickness of FeMn. Spin dynamics and 

the Gilbert damping constants of exchange biased NiFe/FeMn bilayers are investigated 

by the analysis of FMR spectra. The exchange bias field induced asymmetry in the 

magnetization hysteresis loops. It implies the spin dynamics must be asymmetry 

for positive and negative field region. We perform VNA-FMR measurement for 

positive and negative fields. In results, we find that the apparent damping parameters 

are different in the both field directions in the exchange biased NiFe/FeMn bilayers. 

Therefore, we conjecture that the exchange bias layer acts differently, depends on the 

relative direction of the ferromagnetic layer magnetization to the exchange bias field. 

RK03 

Non-linear susceptibility and influence of the applied magnetic field on 

ZFC/FC curves 

Florent Tournus*, Arnaud Hillion, Alexandre Tamion and Veronique Dupuis 

LPMCN, CNRS & Univ. Lyon 1 , France 

ZFC/FC curves are widely used to characterize assemblies of magnetic nanoparticles. 

They reflect the crossover between the blocked and superparamagnetic (SP) regime 

with increasing temperature. With a low applied field a linear response can be assumed, 

the shape of the curves is then independent of the applied field H, and a simple 

theoretical modeling is possible: this allows efficient theoretical fits of experimental 

curves. We have studied the influence of the applied field magnitude on the ZFC/ 

FC curves shape, both theoretically and experimentally. While the effect of H on the 

energy barriers has already been discussed, its effect on the response of SP particles 

has not been considered. However, this non-linearity manifests itself much before 

the modification of the switching energy distribution. In addition to experimental 

measurements on a diluted Co nanoparticle assembly, we have simulated ZFC/FC 

curves for different applied fields, including the third-order susceptibility in the SP 

response. The later depends on the anisotropy and does not at all correspond to a 

Langevin function around the blocking temperature. We find that the curves can be 

significantly affected (in particular the low temperature limit of the FC) for quite low 

applied fields, which are usually used in experiments. 


RK04 

On the relation between the magnetoelastic effect and the damping 

constants of (Ni-Fe) 1-xM x (M = Ag, Cr, Ga, Au, Pd, and Pt) films 

Yasushi Endo*, Yoshio Mitsuzuka, Yutaka Shimada and Masahiro Yamaguchi 

ECEI, Graduate School of Engineering, Tohoku University, Japan 

The dynamics of magnetic thin films have received attention in magnetic device 

applications such as recording heads, media, and MRAM. Although the dynamics 

significantly depend on the damping constant α, which determines the strength of 

damping torque in magnetic thin films, details about their damping mechanism, 

especially the magnetoelastic effect on damping remain unclear. Herein to clarify the 

effect of λs on α in (Ni-Fe) 1-xM x films in detail, we evaluated α and λs in these films. 

For M= Au, Pd, and Pt, α increases linearly and negative λs increases as x increases. In 

contrasts, α and positive λs tend to increase almost linearly with x when M=Ag, Cr, and 

Ga. These results provide clear evidence that α is correlated with λs in (Ni-Fe)-M films. 

Furthermore, increments of α and the absolute value of λs to x are markedly enhanced 

in the order of M = Pt, Au, Pd, Cr, Ag, and Ga, suggesting that 5d transition metal 

dopants are more influential on both α and λs than 3d and 4d transition metal dopants 

due to the strong spin-orbit interaction of 5d dopants. Consequently, these results 

demonstrate that a change in magnetostriction energy via transition metal dopants can 

effectively control α. 

This work is partly supported by KAKENHI (No. 23686047) from MEXT, Japan, A-STEP from JST, 

Japan, and SRC. 

RK05 

Ultrafast magnetization dynamics of ferromagnetic systems induced 

by mid infrared laser pulses 

Amani Zagdoud, Mircea Vomir, Michele Albrecht and Jean-yves Bigot 

IPCMS, France 

The aim of the present study is to show how the ultrafast demagnetization and the 

subsequent rapid re-magnetization occur when exciting a ferromagnetic material with 

low energy infrared pulses. We have used mid-infrared femtosecond laser pulses (λ= 

[3-10 μm]) to excite CoPt3, Ni and Co ferromagnetic thin films. The magneto-optical 

response is then probed in the visible (λ = 798nm). Our results show that even though 

only intraband transitions occur, the demagnetization process and its subsequent 

relaxation to the lattice and to the environment are still the dominant processes 

involved in the magnetization dynamics. We also show that the material band structure 

is important to interpret the thermalization dynamics of the spins that occur before 

the heating of the lattice. For specific experimental configurations, we show that it is 

possible to induce a motion of precession of the magnetization around the effective 

magnetic field and observe it while it is damped. The magnetization dynamics induced 

at 6.5 μm in nickel shows an oscillatory behaviour with a period of 2 ps. We attribute 

this result to the excitation of a two-magnons mode on the NiO by an acoustic mode 

generated in nickel. 

RK06 

Ferromagnetic resonance of bilayer CoFeB/NiFeSiB thin film 

Sanghoon Jung 1 , Chang Ho Choi 1 , Jungbum Yoon 2 , Chun-yeol You 2 , Seung Hyun 

Kim 3 , Young Keun Kim 3 and Myung-hwa Jung 1 

1 Sogang University, Korea 

2 Inha University, Korea 


Spin transfer torque magnetic random access memory (STT-MRAM) is one of the 

candidates for next generation random access memory. For practical application, the 

device should have high thermal stability and low critical current density. They have 

strong correlation with saturation magnetization (Ms) and damping constant (α) so that 

we need to determine Ms and α. To study the damping mechanism of the thin films, we 

have performed ferromagnetic resonance (FMR) experiments through vector network 

analyzer with bilayer thin films of CoFeB(10-x nm)/NiFeSiB(x nm) (x=0,1,2,….,10). 

We have fitted the FMR data with Lorentz function to get the information of resonance 

frequency and line width. From these two fitting parameters, we could get Ms and α by 

Kittel formula and Full Width at Half Maximum. As increasing x values, the Ms tends 

to increase, whereas the α suddenly decrease and then saturate. This implies that the 

added NiFeSiB layer in CoFeB plays a role to prevent the spins align along the field 

direction.

RK07 

Observation of non-kittel ferromagnetic resonance in Co/Cu 

multilayer system 

Faris B. Abdul Ahad 1 , Yu-che Chiu 1 , Shang-fan Lee 2 * and Dung S Hung 3 


2 Institute o Physics, Academia Sinica, Taiwan 

3 Information and Telecommunications Engineering, Ming Chuan University, Taiwan 

In this research, we study the ferromagnetic resonance behavior (FMR) of Co/Cu multilayer system. 

The samples stacking Ta (5nm) / [Co (4nm) / Cu (t)]*10 / Ta (5nm) with t = 0.5 ? 6 nm were prepared 

by dc magnetron sputtering in a multitarget sputtering chamber at room temperature and 1 mTorr of pure 

Ar-pressure. The magnetoresistance (MR) was measured by the standard four point measurement with 

current in plane (CIP) configuration using Quantum Design Physical Properties Measurement System 

(PPMS). The magnetic hysteresis loops were recorded using a Vibrating Sample Magnetometer (VSM). 

FMR responses were measured at microwave frequencies by means of a Vector Network Analyzer (VNA) 

equipped with a low pass filter circuit. Clear FMR responses were recorded for all samples, however, 

the noise increased for samples with thicker spacer. Then resonance frequencies (fr) acquired from FMR 

responses. Theoretically, this FMR should follow Kittel frequency given by: fr=(γ/2π)√H(H+4πM). 

However, our results shows that the resonace linewidth and the deviation of resonance frequency from 

kittel behavior will increases as the spacer thickness increased. This behavior is the result of RKKY 

interaction evident by the increased GMR and will be dicussed within the manuscript. 

1. N. Smith and P. Arnett, Appl. Phys. Lett. 78, 1448 (2001). 2. N. Smith, J. Appl. Phys. 90, 5768 (2001). 3. J. C. Jury, et.al, 

IEEE Trans. Magn. 38, 3545 (2002). 4. Z. Jin and H. N. Bertram, IEEE Trans. Magn. 38, 2265 (2003). 5. Abdul Ahad F. 

B., Hung D. S., Chiu C. Y. and Lee S. F., IEEE Trans. Mag. 47, 4227 (2011). 6. Hung, D. S.; Fu, Y. P.; Lee, S. F.; Yao, Y. D.; 

Abdul Ahad, Faris B, J. Appl. Phy. 107, 09A503 (2010). 7. B. Heinrich and J.F. Cohran, Adv. Phys. 42, 523 (1993). 

RK08 

Neighboring layer dependence of ultrafast thermo-magnetic property 

in GdFeCo films 

Arata Tsukamoto*, Tetsuya Sato, Shingo Toriumi, Ryutarou Shimizu and Akiyoshi Itoh 

Electronics & Computer Science, College of Science and Technology Nihon 


Femtosecond pulsed laser light allow excitation of magnetic systems much shorter than the time scale of 

thermal diffusion represented by conventional Fourier's law. In this time scale, heating and demagnetization 

phenomena arise via strongly non-equilibrium non-adiabatic way, and cannot be explained by conventional 

equilibrium thermo dynamics description[1]. In this study, we investigated the neighboring layer dependence 

of ultrashort laser-induced thermal/magnetic response in layered GdFeCo films by all-optical pumpprobe 

method. Simultaneously, change of normalized reflectivity was measured for monitoring the time 

evolution of electron temperature Te. We designed layered structures as same 20 nm thick GdFeCo with 

different neighboring layers (conductive AlTi and insulating SiN). We found two characteristic time region 

from magnetic behavior: (A) rapid step-like demagnetization and (B) following recovering process with 

precessional motion. The time scale of (A) is conformed as within picoseconds range (time constant ~100 

fs) independently with film structure, which is much shorter than ferromagnetic resonance (period ~0.1 ns at 

10 GHz ) and hundreds fs delayed with respect to the increase of Te. Following regime (B), film structural 

dependency of precessional magnetic motion was appeared. The difference of precession frequency and 

damping properties indicate the different time evolution of lattice temperature in magnetic layer. 

[1] I. Radu, K. Vahaplar, C. Stamm, T. Kachel, N. Pontius, H. A. Durr, T. A. Ostler, J. Barker, R. F. L. Evans, 

R. W. Chantrell, A. Tsukamoto, A. Itoh, A. Kirilyuk, Th. Rasing and A. V. Kimel, Transient ferromagnetic-like 

state mediating ultrafast reversal of antiferromagnetically coupled spins, Nature, 472 (2011) 205. 

RK09 

Magnetization dynamics in perpendicular magnetic anisotropy CoFeB/ 

MgO system 

Jeong Woo Sohn 1 , Ji-wan Kim 1 , Kyeong-dong Lee 1 , Hyon-seok Song 1 , Il-jae Shin 2 , 

Byoung-chul Min 2 , Chun-yeol You 3 and Sung-chul Shin 4 * 

1 

Department of Physics, Center for Nanospinics of Spintronic Materials, KAIST, 

Korea 

2 

Center for Spintronics Research, KIST, Korea 

3 


4 

Center for Nanospinics of Spintronic Materials, KAIST, Department of Emerging 

Materials Science, DGIST, Korea 

We study the ultrafast magnetization dynamics of perpendicularly magnetized MgO/CoFeB/Ta 

and Ta/CoFeB/MgO stack structures which gains wide attention from a viewpoint of perpendicular 

magnetic tunnel junctions. An all-optical time-resolved magneto-optical Kerr effect measurement 

reveals that effective Gilbert damping α stays unchanged at ~0.02 in high external field regardless 

of pump fluence, but it declines drastically with the increase of pump fluence in weak external field. 

This can be explained by the enlarged apparent relaxation time due to slow remagnetization. Genuine 

damping tends to attract the precessing magnetization vector towards the effective equilibrium axis, 

while the tip of the reduced magnetization vector after pump pulse heating recovers growing away 

from the effective axis. These two competing contributions determine the apparent relaxation time. 

In a weak field regime, slow recovery of the magnetization vector results in the increased relaxation 

time and low effective Gilbert damping. We believe that low Gilbert damping found in CoFeB/MgO 

structure will be expected to reduce the critical current for current-induced magnetization switching. 

RK10 

RK11 

RK12 


Composition dependence of the gilbert damping constant for co-based 

heusler alloy 

Yuichi Kasatani 1 , Shinya Yamada 2 , Masanobu Miyao 3 , Kohei Hamaya 4 , Hiroyoshi Ito 5 and Yukio Nozaki 6 * 


2 Department of Electronics, Kyushu University, Japan 

3 Department of Electronics, Kyushu University / CREST, JST, Japan 

4 Department of Electronics, Kyushu University / PREST, JST, Japan 

5 Department of Pure and Applied Physics, Kansai University / CREST, JST, Japan 

6 Department of Physics, Keio University / CREST JST, Japan 

Spin polarized current attracts much attention to operate the magnetic memory devices. To reduce the 

spin current density, the materials with small Gilbert damping are needed. Recently, it is reported that the 

Gilbert damping constant of Co-based Heusler alloy known as half-metallic ferromagnet is less than 0.01[1], 

although the Gilbert damping factor of Co-based Heusler alloy are closely related to crystalline structure 

and concentration ratio. In this study, to understand the damping mechanism in high-quality L 21-type Cobased 

Heusler alloy we measured ferromagnetic resonance (FMR) and estimated the Gilbert damping 

factor. 25 nm thick L2 1-type Co 2-xFe xSi (x=0, 1, 1.5) films for which degree of crystalline order were found 

to be about 70%[2] were grown on Si(111) substrates. The saturation magnetization of Co 2-xFe xSi with 

x=0, 1, 1.5 are 1106, 1023 and 980 emu/cm 3 , respectively. SiO 2 insulating layer and coplanar waveguides 

(CPW) which consists of Ti (5 nm)/Au (60 nm) were prepared. Following that, FMR was measured 

using a vector network analyzer. The results show the Gilbert damping constant inversely proportional 

to saturation magnetization. Considering the electron density of state from the ab initio calculation, the 

broadening of FMR spectra is considered to be related to the electron density of state. 

[1] T. Kubota, S. Tsunegi, M. Oogane, S. Mizukami, T. Miyazaki, H. Naganuma and Y. Ando, Appl. Phys. Lett., 94 122504 

(2009). [2] S. Yamada, K. Hamaya, K. Yamamoto, T. Murakami, K. Mibu and M. Miyao, Appl. Phys. Lett., 96, 082511 (2010). 

Detection of picosecond magnetization dynamics of 50 nm magnetic 

dots down to the single nanodot regime 

Bivas Rana, Dheeraj Kumar, Saswati Barman, Semanti Pal, Yasuhiro Fukuma, 

Yoshichika Otani and Anjan Barman* 

Condensed Matter Physics and Material Sciences, S. N. Bose National Centre For 

Basic Sciences, India 

We present the detection of the picosecond dynamics in arrays of 50 nm permalloy dots 

down to the single nanodot regime by an all-optical time-resolved magneto-optical Kerr 

effect microscope. The inter-dot separation (S) varies from 200 to 50 nm and simulated 

magnetostatic fields shows a transition from magetostatically isolated to strongly coupled 

regime as S decreases. Consequently, we observe a single precessional mode for S down to 

75 nm, whose frequency increases with the decrease in S. At the smallest separation S = 50 

nm, we observe a mode splitting. The simulated mode profile reveals that the dynamics of 

a single 50 nm dot is dominated by the edge mode. In sparsely packed arrays we primarily 

observe the isolated dynamics of the constituent dots in phase. For S = 50 nm, we observe an 

additional backward volume magnetostatic mode of the array. The damping is minimum for 

S = 200 nm but increases linearly with the decrease in S as a result of the dynamic dephasing 

of the precession of the weakly interacting dots. At S = 50 nm, the dephasing due to the 

superposition of two resonant modes results in a sudden increase in the apparent damping. 

1. B. Rana, S. Pal, S. Barman, Y. Fukuma, Y. Otani, and A. Barman, Appl. Phys. Express 4, 113003 (2011). 2. A. 

Barman, S. Wang, J. D. Maas, A. R. Hawkins, S. Kwon, A. Liddle, J. Bokor, H. Schmidt, Nano Lett. 6, 2939 (2006). 

3. B. Rana, D. Kumar, S. Barman, S. Pal, Y. Fukuma, Y. Otani, and A. Barman, ACS Nano 5, 9559 (2011). 

Femtosecond demagnetization in Ni: Electron-phonon spin flip 

scattering from first principles 

Karel Carva 1 , Marco Battiato 2 and Peter M Oppeneer 2 

1 DCMP, Charles University in Prague, Czech Republic 

2 Uppsala University, Sweden 

The femtosecond demagnetization discovered in 1996 [1] represents a critical test of magnetization 

dynamics theories and may lead to many interesting applications. It is still far from being understood 

on a microscopic level. Electron-phonon spin-flip scattering in Ni was suggested to be the microscopic 

explanation of its femtosecond laser-induced demagnetization [2]. We have calculated the spin-flip 

Eliashberg function [3] based on ab initio electron-phonon coupling matrix elements, which allows us 

to obtain the spin-flip probability with much higher accuracy. We extend this method also to the regime 

of non-equilibrated electron distributions relevant for ultrafast processes. We have found that the spinflip 

probability depends strongly on electron energy. We consider two cases for system excited by a laser: 

thermalized very hot electron distributions, as well as highly non-equilibrium electron distributions that are 

expected to be present immediately after the fs laser excitation. Employing this approach we compute the 

electron-phonon SF rates. We find that the demagnetization rate is very low for any thermalized electron 

distribution as compared to non-equilibrium distributions present within first femtoseconds following the 

pump laser [3]. This is due to the density of states and the specific energy-dependence of SF probability. 

[1] E. Beaurepaire, J.-C. Merle, A. Daunois J.-Y. Bigot, Phys. Rev. Lett. 76, 4250 (1996). [2] B. Koopmans, 

G. Malinowski, F. Dalla Longa, D. Steiauf, M. Fahnle, T. Roth, M. Cinchetti, M. Aeschlimann, Nature 

Mater. 9, 259 (2010). [3] K. Carva, M. Battiato, P. M. Oppeneer, Phys. Rev. Lett., 107, 207201 (2011) 


Poster Thursday



RK13 

Ultrafast magneto-acoustic pulses in a nickel film 

Jiwan Kim, Mircea Vomir and Jean-yves Bigot* 

Physics, IPCMS, CNRS, France 

We report about the ultrafast magnetization dynamics induced by magneto-acoustic 

pulses in a 200-nm-thick Ni film generated with femtosecond laser pulses. The 

magneto-acoustic pulses result from the coupling between the magnetization and 

the acoustic waves generated by the laser pulses. In order to distinguish between 

dynamical magnetic effects induced either by the thermal excitation or by the magnetoacoustic 

pulse, the spin dynamics is measured from both the front and rear sides of the 

film via the magneto-optical Kerr technique. It is found that the acoustic pulses excite 

the magnetization on both sides of the film and the perturbation of the magnetization 

is very efficient at the rear side (10% of the static one). Using a detailed modeling 

of magneto-acoustic pulses combining the concepts of acoustic pulse propagation 

and ultrafast magnetization dynamics, we reproduce the magnetization dynamics on 

both sides of the film. In addition, our results imply that the magnitude of magnetoacoustic 

pulses can be controlled and maximized by selecting proper substrates with 

same ferromagnetic materials. We forecast that our results will have a strong impact 

for making ultrafast magneto-acoustic devices, with the capability of sensing the 

magnetization at relatively long distances from acoustic pulses generated by the laser 

pulses. 

RK14 

Minimal precessional and switching currents for relaxing-precessional 

magnetization reversal within a spin valve 

Jui-hang Chang*, Hao-hsuan Chen and Ching-ray Chang 

Physics, National Taiwan University, Taiwan 

The relaxing-precessional magnetization reversal [1] is studied from the point of view 

of nonlinear dynamics. The solution of the Landau-Lifshitz-Gilbert equation with 

spin-transfer toque [2] shows that there are two critical values, α_cs and α_cp, for the 

damping constant, and α_cs < α_cp. Above α_cs the minimal switching current a_ 

s is the same as the modified Stoner-Wolfarth (SW) limit [3] a_cs for the switching, 

and above α_cp the minimal precessional current a_p is the same as the modified SW 

limit a_cp for the onset of precession. For a given magnetic anisotropy and an arbitrary 

in-plane bias field, condition a_s < a_cs < a_p < a_cp always happen, where a_s, a_ 

p are functions of α_s, α_p, respectively. These investigations will be of importance 

for the design of spin-torque-transfer magnetic random access memories [4] and nano 

oscillators [5]. 

[1] H. Morise and S. Nakamura, J. Magn. Magn. Mater. 306, 260 (2006). [2] J. C. Slonczewski, 

J. Magn. Magn. Mater. 159, L1 (1996). [3] J. H. Chang, H. H. Chen, and C. R. Chang, Phys. Rev. 

B 83, 054425 (2011). [4] U. Ebels, D. Houssameddine, I. Firastrau, D. Gusakova, C.Thirion, B. 

Dieny, and L. D. Buda- Prejbeanu, Phy. Rev. B 78, 024436 (2008). [5] D. Houssameddine, U. 

Ebels, B. Delaët, B. Rodmacq, I. Firastrau, F. Ponthenier, M. Brunet, C. Thirion, J. -P. Michel, L. 

Prejbeanu-Buda, M. -C. Cyrille, O. Redon, and B. Diney, Nature Mater. 6, 447 (2007). 

RK15 

Time dependent dichroism induced near the Surface Plasmon of Au 

nanoparticles 

Jean-yves Bigot 1 * and Minji Gwon 2 

1 Institute de Physique et Chimie des Materiaux de Strasbourg, CNRS, Universite de 

Strasbourg, Korea 

2 Ewha Womans University, Korea 

We have studied the Surface Plasmon (SP) dynamics of Au Nanoparticles, with a 

diameter of 50 nm, excited by circularly polarized femtosecond laser pulses. We report 

about a new effect observed in a time resolved pump-probe experiment, analyzing 

the polarization state of the probe pulses. It manifests as a circular dichroism and an 

optical rotation induced in the vicinity of the SP when pumping with left (σ+) or right 

(σ-) circularly polarized pulses. We attribute this effect to a time dependent change of 

the orbital momentum of conduction electrons as the effect is more pronounced when 

the nanoparticles are excited with a pump wavelength -pump = 800 nm as compared to 

400 nm. Indeed, in that case the interband transitions from the d-band to the conduction 

band are minimized with respect to the Drude electrons. The induced dichroism is 

resonant on the SP (560 nm). Its lifetime is comparable to the energy relaxation time 

of the quasiparticles to the lattice. It suggests that the electron-phonon interaction 

is the main mechanism for the dissipation of this pump induced orbital momentum. 

The detailed behavior of the SP dynamics as a function of probe wavelength, pump 

polarization and pump-probe delay will be discussed. 


RK16 

The effect of surface anisotropy on the switching of a particle magnetic 

moment 

Shuang Guo and An Du* 

Physical department, Northeastern University, China 

The effect of surface anisotropy on the switching of a particle magnetic moment 

Shuang Guo, An Du* College of Sciences, Northeastern University, Shenyang 110004, 

China * Corresponding author(du_an_neu@126.com) The dynamic precession 

of the moment for a spherical particle in a microwave field was studied by using 

Landau-Lifshitz-Gilbert (LLG) equation. The spins inside the particle have singleion 

anisotropy and the ones on the surface of the particle have the surface anisotropy 

normal to the surface. The switching field threshold was calculated for different surface 

anisotropy with definite microwave frequency. It is found that the surface anisotropy 

influences the switching field threshold, with the increase of the surface anisotropy, the 

threshold increases, the switching speed of the magnetic moment increases obviously. 

1. K. Rivkin, and J. B. Ketters, Appl. Phys. Lett. 89, 252507(2006). 2. J.G. Zhu, X. Zhu, and Y. 

Tang, IEEE Trans. Magn. 44, 125(2008). 3. S. Okamoto, N. Kikuchi et al, Appl. Phys. Lett. 93, 

102506(2008). 4. S. Okamoto, N. Kikuchi, and O. Kitakami, Appl. Phys. Lett. 93, 142501(2008). 5. M. 

Lgarashi, Y. Suzuki et al, J. Appl. Phys. 105, 07B907(2009). 

RK17 

Magnetization dynamics of GdFeCo nanostructures revealed with 

PEEM 

Souliman El Moussaoui 1 *, Loic Le Guyader 1 , Michele Buzzi 1 , Elena Mengotti 1 , 

Laura J. Heyderman 1 , Frithjof Nolting 1 , Thomas A. Ostler 2 , Joe Barker 2 , Richard F. 

L. Evans 2 , Roy Chantrell 2 , Arata Tsukamoto 3 , Akiyoshi Itoh 3 , Andrei Kirilyuk 4 , Theo 

Rasing 4 and Alexey V. Kimel 4 

1 

Paul Scherrer Institut, Switzerland 

2 

Department of Physics, University of York, United Kingdom 

3 

Nihon University, Japan 

4 

Radboud University Nijmegen, Institute for Molecules and Materials, Netherlands 

The manipulation of spins is a very exciting topic from fundamental point of view as well as for practical 

applications. Combining experiments and simulation, we have been able to demonstrate that a fs-optical 

excitation is sufficient to trigger magnetization reversal in GdFeCo nanostructures on very short timescales. 

Employing a photoemission electron microscope (PEEM) at the SIM beamline, we have proved that we can 

manipulate the magnetization of nanostructures by using a heat pulse only. Performing time resolved X-ray 

magnetic circular dichroism (TR-XMCD) measurement we have observed that the magnetization reversal 

within the structures occurs on a timescale faster than 100 ps and evidenced that the reversal occurs against 

an external applied magnetic field. In our experiment the reversal happens only by heating the system on the 

time scale of the exchange interaction of the two sublattices and does not require any other external stimulus. 

'Ultrafast heating as a sufficient stimulus for magnetization reversal' T. A. Ostler, J. Barker, R. F. L. Evans, R. Chantrell, U. Atxitia, O. 

Chubykalo-Fesenko, S. El Moussaoui, L. Le Guyader, E. Mengotti, L. J. Heyderman, F. Nolting, A. Tsukamoto, A. Itoh, D. Afanasiev, 

B. A. Ivanov, A. M. Kalashnikova, K. Vahaplar, J. Mentink, A. Kirilyuk,Th. Rasing and A. V. Kimel, Nature Comm. 3, 666 (2012). 

RK18 

A study of magnetic domain and magnetization reversal in L-shaped 

Py 

S.s. Lee, Wondong Kim, Byong Sun Chun and Chanyong Hwang* 


The evaluation of characteristic of nanometer-sized magnetic domain is one of the 

most important issues in the fields of spintronics. We made the Py stripe with and 

without the L-shaped edge structure. First, magnetic domain and its reversal reversal 

behavior were simulated with the use of OOMMF program. Depending on the 

thickness, width of this L-shaped structure, magnetic domain and its reversal behavior 

could be classified in several groups. We also used scanning electron microscope with 

polarization analysis(SEMPA, or spin-SEM) to probe the magnetic domain pattern 

predicted in the simulation.

RK19 

Ultrafast dynamics of ferromagnetic copd thin film by various 

polarized probe beam 

S. H. Jung 1 , M. H. Jung 1 , Jin Pyo Hong 2 , Won Dong Kim 3 , Chanyong Hwang 3 * and 

Joo In Lee 3 


2 Department of Pysics, Hanyang University, Korea 

3 Center for Nano-imasing Technology, Korea Research Institute of Standards and 


We study ultrafast dynamics of the ferromagnetic CoPd thin film by using timeresolved 

magneto-optical Kerr effect. In the case of using linearly polarized probe 

beam, the spin precession is observed in the frequency of about 14 GHz in the range 

of large time scale. On the other hand, when the probe beam changes to circular 

polarization, the large time scale precession disappears, and ultrafast precession 

(~100GHz) is observed in short time scale. We suppose that these result from the 

momentum change of probe beam from 0 to 1, and the ultrafast precession is related to 

interaction between spin and circularly polarized photon. 

1. J.-Y. Bigot, Physics 5, 11 (2012) 2. J.-Y. Bigot, M. Vomir, E. Beaurepaire, Nature Physics 5, 515 

(2009) 

RK20 

Low temperature time domain THz spectroscopy of terbium gallium 

garnet crystals 

Rostislav V. Mikhaylovskiy*, Euan Hendry, Feodor Y. Ogrin and Volodymyr V. 

Kruglyak 

School of Physics, University of Exeter, United Kingdom 

We have used the terahertz (THz) time domain spectroscopy to study high frequency 

magnetic excitations in terbium gallium garnet (TGG) crystals cut along 

and crystallographic planes. We demonstrate that a THz bandwidth transient 

electromagnetic pulse can efficiently couple to magnetic moments in TGG. By 

comparing the spectrum of the pulse before and after transmission through the crystal, 

we are able to isolate the absorption corresponding to magnetic resonance modes 

of TGG. We measure and discuss the dependence of the observed modes upon the 

temperature and the strength and orientation of the bias magnetic field with respect 

to the crystallographic axes of the crystals. The magnetic modes are present at 

temperatures above the Neel point, which is interpreted in terms of the field-induced 

magnetic ordering. The illumination of the crystal with intense optical pulses with 

wavelength close to the TGG absorption band destroys the magnetic ordering. Thus, 

the light induced demagnetization of TGG is observed. Our findings demonstrate that 

the time domain THz spectroscopy can be a powerful tool by which to study high 

frequency properties of dielectric magnetic materials. 

RK21 

Ferromagnetic resonance of a single micron dot using vector network 

analyzer 

Kazuto Yamanoi 1 , Satoshi Yakata 2 , Takashi Kimura 2 and Takashi Manago 1 * 

1 Department of Applied Physics, Fukuoka University, Japan 

2 Inamori Frontier Research Center, Kyusyu University, Japan 

Magnetization dynamics of small ferro-magnets in the gigahertz region have been 

investigated intensively for the applications in microwave devices. It is based on the 

precessional motion of magnetization and it is necessary to control one of each small 

magnets in devices. In this paper, we investigated ferromagnetic resonance (FMR) of 

a single miconscale dot of permalloy (Py) using a vector network analyzer (VNA). A 

micron-scale Py dot and a coplanar wave guide were fabricated using electron beam 

lithography, electron beam evaporation and lift off technique. The thickness of the Py 

dots was 30 nm, and the shapes were square and rectangle with a width and length of 

1~10 um and 1~40 um, respectively. The FMR measurement was performed using 

the VNA and probe station. In the square shape dot of 10 um, the resonant frequency 

depends on magnetic fields, which was good agreement with the Kittel’s equation 

of a thin film. In the rectangle shape dots, the resonant frequency shifted to higher 

frequency with increasing length. This tendency was remarkable for 1 um-width dots. 

It means that demagnetization effect becomes large when the width is less than 1 um 

for a thin film. 

RK22 

RK23 

RK24 


Relation between gilbert damping constants and perpendicular 

magnetic anisotropy in Ti buffered Co/Ni multilayers 

Hyonseok Song 1 , Kyeong-dong Lee 1 , Jeong-woo Sohn 1 , See-hun Yang 2 , Stuart S.p. 

Parkin 2 , Chun-yeol You 3 and Sung-chul Shin 4 * 

1 Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, Daejeon 305-701, Korea 

2 IBM Research Division, Almaden Research Center, San Jose, California 95120, USA 

3 Department of Physics, Inha University, Incheon 402-751, Korea 

4 Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, Daejeon 305-701, 

Department of Emerging Materials Science, DGIST, Daegu 711-873, Korea 

Recently, there has been a growing interest in spin-transfer-torque magnetic random access memory utilizing 

perpendicularly magnetic anisotropy (PMA) materials in order to overcome thermal stability problems. 

Since the critical current density depends on the Gilbert damping parameter, it has been an important 

issue to understand and manipulate the Gilbert damping parameter in the PMA materials. In this work, 

we have investigated PMA [Co/Ni] multilayers with Ti buffer layers by an all-optical pump-probe time 

resolved magnetic optical Kerr effect (TR-MOKE). In particular, we have studied the variation of Gilbert 

damping constant (α) and PMA as a function of the thickness of Ti buffer layer thickness (t). Since the PMA 

and damping constant are strongly related with the spin-orbit coupling, both physical quantities must be 

correlated. Clear damped oscillations of the magnetization are observed in TR-MOKE measurements. After 

background subtraction, the signal is fitted with a damped harmonic function, from which the precession 

frequency (f) and the decay time (τ) are deduced. We obtained f and τ by fitting with Landau-Lifshitz- 

Gilbert equation, and we could be estimated α. We find that The α and PMA values increased monotonically 

with increasing of t. This result clearly shows close relationship between PMA and α. 

Chaotic motion of magnetic domain structure under alternate field 

Michinobu Mino* and Yousuke Yamamoto 

Department of Physics, Okayama University, Japan 

Magnetic domain motion in a garnet thin film under alternate magnetic fields up to 

5000 Hz has been investigated at room temperature. Domain structures and motions are 

observed by using a high-speed video camera with the help of magneto-optical Faraday 

effect. When a field frequency is low, the magnetization changes periodically and a 

domain pattern has a labyrinth structure. By increasing the field amplitude and driving 

frequency, irregular oscillations of a magnetization appear. Under a rapidly oscillating 

field, chaotic motions of domain are observed. In this region, domain structures have 

a disk-like shape. These disks grow from some crystal defects. And a growing point 

shows a branch-like form. 

Demagnetization dynamics observed by spin-resolved ultrafast x-ray 

photoemission 

Thomas Michlmayr 

Physics, ETH Zurich, Switzerland 

We report on the experiment and the results of time- and spin-resolved photoemission. 

Ultrafast demagnetization was first observed by Beaurepaire et al. in 1996 and many 

approaches where done to support these findings. Our method allows for measuring 

the whole valence band mediated by the cascade electrons emerging from the 

sample and therefore gives a direct measure of the sample's magnetization. Ultrafast 

demagnetization is observed on thin films of Fe on W(110) by optical pumping at 800 

nm and x-ray probing at 7 nm. The measured demagnetization time of 450 fs is limited 

by the experiment. Although space charge effects limits the photoelectron gain the 

measured spin asymmetry stays almost constant with increasing x-ray flux and only 

drops at very high x-ray fluxes (> 4 nJ/pulse). We also show the feasibility of single 

shot magnetic measurement. The experimental setup consists of a completely mobile 

two chambers ultra-high vacuum system (preparation and measurement chamber) with 

Mott-polarimeter which can be brought to the free electron laser FLASH, Hamburg. 


Poster Thursday


RL01 


Synchronized modes of in-plane/out-of-plane spin-torque oscillators in 

MTJ with synthetic ferrimagnetic free layer 

Masahiko Ichimura 1 *, Ryoko Sugano 1 , Saburo Takahashi 2 and Sadamichi Maekawa 3 

1 Central Research Lab., Hitachi, Ltd. and JST-CREST, Japan 

2 IMR, Tohoku University and JST-CREST, Japan 

3 Advanced Science Research Center, Japan Atomic Energy Agency and JST-CREST, 

Japan 

There has been considerable interest in the phenomena of spin-torque oscillators (STO) in 

magnetic tunnel junctions (MTJs) for device applications, as well as the current induced 

magnetization switching (CIMS) resulting from the spin transfer torque (STT). In particular, 

the MTJs with synthetic ferrimagnetic (SyF) free layer is important since we can expect 

the cooperation and/or competition of the magnetization dynamics due to the interlayer 

coupling between magnetizations in the ferromagnetic bilayer. We analyze the magnetization 

dynamics self-consistently in the MTJs with SyF layer by iterative calculation following 

two steps. The STT in the ballistic regime is estimated, and the magnetization reversal is 

simulated by the LLG method at the finite temperature. We discuss the effect of the interlayer 

coupling on the STO. As the interlayer coupling increases, the change of the STO mode is 

observed, where the STO mode moved from the out-of-plane precession (OPP) to in-plane 

precession (IPP). From the mapping of the STO behavior on the plane with applied current 

and interlayer coupling, synchronized mode of STO appears in the region where the effective 

filed corresponding to the interlayer coupling is larger than the anisotropy field. These results 

suggest that the STO appears even without external magnetic field. 

RL02 

Interface material effects on magnetic anisotropy and its electric field 

induced variation in thin films 

Yuusaku Taguchi 1 *, Haruki Kato 1 , Shinya Haraguchi 1 , Masahito Tsujikawa 2 , 

Masafumi Shirai 3 and Tatsuki Oda 4 

1 

Graduate School of Natural Sciences and Technology, Kanazawa University, Japan 

2 

CSIS, Tohoku University, Japan 

3 

CSIS, Tohoku University & RIEC, Tohoku University, Japan 

4 

Institute of Science and Engineering, Kanazawa University, Japan 

The spintronics has grown up intensively to realistic applications in the technology of magnetic random access 

memory (MRAM) development. Such development has been remarkable in memory density, reading-writing 

speed, and non-volatile property in cooperation with the technologies of spin-injection and physics of spin 

transfer torque. The basic physics about magnetism has been developing in the response to electric field (EF). 

This has emerged as the connection with low power consumption device and small energy scale of magnetoelectric 

effects. For the thin films [1,2] as a memory, sensitivity and large response may be required in device 

applications. Due to the limitation of EF penetration into the thin film, interface with a few metallic layers is 

critical to determine the response to the EF. We have investigated MgO/Fe/M(001) (M = Au, Pt) [3,4] with using 

the density functional calculation, in which the substrate of Pt was found to enhance the EF effect on magnetic 

anisotropy. In this work, in order to investigate influences of stacking structure for the interface, we investigate 

MgO/Fe/Pt/Au(001) and MgO/Fe/Pd/Au(001). In addition, results in MgO/Au/Fe/Au(001) are also discussed 

in the connection with segregation effects of film preparation, which may be expected in experiments. 

[1] Y. Shiota et al., Appl. Phys. Express 2, 063001 (2009). [2] T. Nozaki et al., Appl. Phys. Lett. 96, 022506 (2010). 

[3] M. Tsujikawa et al., J. Appl. Phys., 109, 07C107 (2011). [4] M. Tsujikawa et al., submitted for publication. 

RL03 

Effect of spin relaxation rate on the interfacial spin depolarization in 

ferromagnet/oxide/semiconductor contacts 

Kun-rok Jeon 1 , Byoung-chul Min 2 , Youn-ho Park 2 , Young-hun Jo 3 , Hun-sung Lee 1 , 

Chang-yup Park 1 and Sung-chul Shin 1 * 

1 Korea Advanced Institute of Science and Technology (KAIST), Korea 

2 Korea Institute of Science and Technology (KIST), Korea 

3 Korea Basic Science Institute (KBSI), Korea 

The electrical injection and detection of spin-polarized carriers in semiconductors (SCs) has been 

successfully achieved by employing spin tunnel contacts and the Hanle effects. However, many aspects 

of the spin phenomena in these systems, e.g., (i) the location, magnitude, and sign of the induced 

spin accumulation, (ii) the unusual bias and temperature-dependence of the spin signal, and (iii) the 

unexpected short spin lifetime and its weak variation with temperature, require additional investigation. 

Here, we report the effect of spin relaxation rate on the interfacial spin depolarization (ISD) from 

the local fields in ferromagnet (FM)/oxide/SC contacts [1]. The combined measurements of normal 

and inverted Hanle effects reveal the effect of spin relaxation rate on the ISD [2] in CoFe/MgO/ 

Si and CoFe/MgO/Ge contacts. We have observed, despite the similar amplitudes of the interfacial 

roughness and local magnetic fields, significant differences of the ISD [2] depending on the host SC; 

the spin accumulation exposed to similar local fields in different SCs give rise to a clearly different 

ratio of the inverted Hanle signal to the normal one. This can be understood in terms of two competing 

mechanisms in the host SCs, namely the spin relaxation and spin precession due to the local fields. 

[1] K. R. Jeon et al., arXiv:1110.5978v1. [2] S. P. Dash et al., Phys. Rev. B 84, 054410 (2011). 


RL04 

Spin-pumping and revelation of inverse spin-Hall effect in n-type Si at 

room temperature 

Mariko Koike*, Eiji Shikoh, Teruya Shinjo and Masashi Shiraishi 


Since spin-orbit interaction in n-type Si is very week due to its band structure and 

lattice inversion symmetry, observation of the spin-Hall effect in n-type Si has been 

believed to be difficult. Here, we report successful observation of the inverse spin-Hall 

effect (ISHE) in n-type Si at room temperature. The sample composes of a Ni 80Fe 20/ 

n-type Si film with a doping concentration of 1.0×10 19 1/cm 3 . The n-type Si surface 

was etched by hydrofluoric acid to remove the naturally-oxidized Si. A ferromagnetic 

Ni 80Fe 20 was formed by using electron beam lithography and deposition methods on 

the n-type Si. Two electrode-pads were attached to the n-type Si layer to detect the 

electromotive force in the Si. In a ferromagnetic resonance condition of the Ni 80Fe 20, 

a pure spin current was injected into the n-type Si layer by the spin pumping. If ISHE 

is induced in the n-type Si, the spin current is converted to a charge current. Here, the 

ISHE in the n-Si was observed. The output voltage due to the ISHE was estimated to 

be 0.4μV. The voltage sign was inverted by the magnetization reversal of the Ni 80Fe 20. 

In this presentation, we discuss details of the inverse spin-Hall effect in the n-type Si. 

RL05 

Critical current density and domain wall mobility in nanowires with 

exchange coupled hard-soft magnetic layers 

Xiaoxi Liu 1 *, Liangqiu Gao 2 and Akimitsu Morisako 2 

1 Department of Information Engineering, Shinshu University, Japan 

2 Shinshu University, Japan 

In this study, critical current density and domain wall mobility of current driven 

domain wall motion in nanowires composed of TbFeCo and NiFe layers have been 

studied. TbFeCo layer has perpendicular magnetic anisotropy. Wires and electrode are 

fabricated by photolithographic method. Current pulses with width less than 100 ns 

are applied to drive the domain wall in the wires. The domain structure is observed by 

a high resolution Kerr microscope. We found critical current density decreases in the 

soft-hard bi-layered structure compared to a single TbFeCo layer. Nanowires of single 

TbFeCo layer have critical current density of 5×10 6 A/cm 2 ; however, the critical current 

density in bi-layered structure has critical current density as small as 2 ×10 6 A/cm 2 . The 

domain wall mobility is deduced from the dependence of domain wall velocity on the 

applied current density. We found that the domain wall mobility improved by almost 

two times with the introducing of the NiFe layer. Of particular interesting is that, 

micromagnetic simulations show that the Bloch walls in perpendicular TbFeCo wires 

change to Neel walls with the introducing of NiFe layer. Our experimental results 

suggest nano-wires composing of soft-hard layers suitable for race track memory. 

RL06 

Spin Seebeck Effect in SiO2/Py structures 

Sang-il Kim 1 , Seung-young Park 2 , Byoung-chul Min 3 , Younghun Jo 2 , Kyung-jin Lee 1 * 

and Kyung-ho Shin 3 

1 

Department of Materials Science and Engineering, Korea University, Seoul 136- 


2 

Nano Material Research Team, Korea Basic Science Institute, Daejeon 305-333, 

Korea, Korea 

3 

Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea, Korea 

Recently, spin version of Seebeck effect, the spin-Seebeck effects (SSE) was observed 

experimentally at room temperature[1]. For the SSE, it is expected that the voltage sign at the 

hot end is opposite to that at the cold end and the absolute magnitudes of the voltages at the 

hot and cold ends are the same. However, it is often observed that an asymmetric magnitude 

of the voltage at the hot and cold ends [2]. The origin of this asymmetric behavior is 

attributed to an additional temperature gradient along the thickness direction, which generates 

an additional voltage signal due to the anomalous Nernst-Ettingshausen effect(ANE) [2]. In 

this study, we investigated the dependence of the SSE and the ANE on the thickness of the 

ferromagnetic layer in SiO 2/Py samples. In our results, the sign change in the voltage signal 

between the hot and cold ends was not observed. Instead, we obtained an offset voltage 

due to the mixture of SSE and ANE signals. We attribute this offset to the longitudinal SSE 

caused by an additional temperature gradient along the thickness direction of Py layer. A 

possible origin of the dependence of offset voltage on Py thickness will be discussed in detail. 

[1] K. Uchida et al., Nature, 455, 778-781 (2008). [2] S. Bosu et al., Phy. Rev. B 83, 224401 (2011).

RL07 

Domain wall pinning by stray field from NiFe on Co/Ni nano-wire 

Ryo Hiramatsu 1 , T. Koyama 1 , D. Chiba 1 , S. Fukami 2 , N. Ishiwata 2 , Y. Nakatani 3 and T. 

Ono 1 * 


2 Green Innovation Research Laboratories, NEC Corporation, Japan 

3 University of Electro-communications, Japan 

Control of a magnetic domain wall (DW) displacement in a ferromagnetic nano-wire 

is essential in its potential application for nonvolatile magnetic memories. Parkin et 

al. demonstrated a race track memory device by controlling DW displacement in a 

NiFe nano-wire with notch structure [1]. However, the structure with notch has two 

problems such as i) transformation of DW structure and ii) increase of current density 

due to the change of the wire width between notch and wire part. Here, to make new 

DW pinning method without the change of wire width, we focus on the DW pinning 

in Co/Ni nano-wire by the stray field from ferromagnetic stack.We prepared two types 

of devices; one was a simple wire of Ta/Pt/[Co(0.2 nm)/Ni(0.6 nm)] 4/Co(0.2 nm)/Pt/ 

Ta, and the other was a wire of Ta/Pt/[Co(0.2 nm)/Ni(0.6 nm)] 4/Co(0.2 nm)/Pt/Ta on 

which NiFe/SiO 2 was stacked partly. To investigate an influence of the stray field from 

the NiFe stack, DW depinning field (H dep) was measured for both types of wires. H dep 

of the wire without the NiFe stack was 200 Oe, while the wire with that had larger H dep 

of 700 Oe, indicating the effectiveness of the use of the stray field to control the DW 

position. 

[1] S. S. P. Parkin, et al., Science 320, 190 (2008). 

RL08 

Compositional dependence of critical current density for spin transfer 

torque switching of amorphous GdFeCo for thermally assisted MRAM 

Bing Dai 1 *, Takeshi Kato 1 , Satoshi Iwata 1 and Shigeru Tsunashima 2 

1 Department of Quantum Engineering, Nagoya University, Nagoya 464-8603, Japan 

2 Department of Research, NISRI, Yotsuya-dori 1-13, Chikusa-ku, Nagoya, 464-0819, 

Japan 

Spin transfer torque (STT) switching has been demonstrated in magnetic tunneling junctions 

(MTJ) with perpendicular magnetic anisotropy (PMA), which exhibits a low critical current 

density compared to their in-plane counterparts [1]. In this paper, we fabricated giant magnetoresistance 

(GMR) devices consisting of bottom electrode/ [Pd (1.6)/Co (0.4)] 6/Co 40Fe 40B 20 

(0.5)/Cu (3)/ Gd x(Fe 90Co 10)100-x (10)/Cu (5)/top electrode (thickness in nanometer). The R-I 

loops were measured for 120×180 nm 2 cell with Gd x(Fe 90Co 10) 100-x memory layers, and the 

STT switching property of these devices was estimated from the resistance measurement after 

applying current pulses with a duration of 100 ms. In TM-rich compositions, the average value 

of the critical current density Jc increased from 2.0×10 7 A/cm 2 for x = 22.3 at.% to 4.5×10 7 A/ 

cm 2 for x = 24.0 at.% with increasing x, while the Jc reduced to 1.4×10 7 A/cm 2 for RE-rich 

Gd 28.9(Fe 90Co 10) 71.1. It is noted that the values of Jc are comparable to the results in conventional 

MTJs[2]. The difference of Jc values may be due to the difference of the effective perpendicular 

anisotropy and/or the Curie temperature of the GdFeCo layer. The dependence of Jc on the 

current pulse width and temperature will be discussed in the presentation. 

[1]S. Ikeda, et al. Nature Materials 9, 721-724 (2010). [2]Y. Huai, et al. Appl.Phys.Lett. 82, 222510 (2005). 

RL09 

Microscopic theory of magnon-drag thermodynamic transport in 

ferromagnetic metals 

Daisuke Miura* and Akimasa Sakuma 


We study the thermodynamic transport carried by magnons in ferromagnetic metals. 

In this study, the Peltier effect caused by a magnon heat current (magnon-drag Peltier 

effect) is described in a microscopic model. Magnons can indirectly interact with 

electric fields via electron-magnon interaction; we evaluate the magnon heat current 

perturbatively with respect to the electron-magnon interaction in the 2nd order. As a 

consequence, we found out that the magnon heat current is proportional to the spin 

current carried by the spin polarized electric current drifted by the electric filed, that is, 

the magnon-drag Peltier coefficient is governed by the spin polarization of the electric 

current. This is in contrast to the phenomenological result derived by Grannemann and 

Berger [1] in which the coefficient is proportional to the electric current directly. In 

addition, we show the temperature dependence of the Peltier coefficient is T 5/2 in low 

temperature. These results indicate that, in the inverse effect (Seebeck effect) of the 

Peltier effect, the magnon heat current caused by a temperature difference induces the 

spin current, and the temperature dependence of the Seebeck coefficient is T 3/2 . 

[1] G. N. Grannemann and L. Berger, Phys. Rev. B 13, 2072 (1976). 

RL10 

RL11 

RL12 


Electric-field control of magnetic properties in cobalt by means of electric double layer 

Kazutoshi Shimamura 1 , Daichi Chiba 2 , Masashi Kawaguchi 1 , Shimpei Ono 4 , Shunsuke Fukami 5 , 

Nobuyuki Ishiwata 5 , Kensuke Kobayashi 3 and Teruo 1 * 


2 Institute for Chemical Research, Kyoto University and PRESTO JST, Japan 

3 Institute for Chemical Research, Kyoto University and Osaka University, Japan 

4 Central Research Institute of Electric Power Industry, Japan 

5 NEC Corporation, Japan 

Electric-field effect on magnetism using a capacitance structure (gate electrode/insulator/ferromagnetic) 

has actively investigated to open up a new technology for an electrically manipulation of magnetization [1- 

10]. Here, we show electric field control of magnetic properties in Co using an electrical double layer (EDL) 

formed at the interface between the Co layer and a polymer film containing an ionic liquid. The polymer 

film containing the ionic liquid was put on a 0.4-nm-thin-Co-film and Pt-thin-film was placed on the top 

of the polymer film as a gate electrode. For the direct detection of the magnetization under the gate-voltage 

(Vg), superconducting quantum interference device [6] was used. Magnetization curves were measured 

at 300 K under the application of Vg from -2.0 V to +2.0 V. Dramatic change of coercivity was observed 

depending on Vg. To investigate the mechanism of this, we measured temperature dependences of the 

remanent magnetization under the different Vg. The significant increase of Curie temperature from ~320 K 

at Vg = 0 V to ~370 K at 2.0 V was observed. Thus, the dramatic change in corecivity at 300 K presented 

here is attributed to this large modulation of Curie temperature [10]. 

[1] H. Ohno et al., Nature 408, 944, (2000). [2] D. Chiba, M. Yamanouchi, F. Matsukura and H. Ohno, Science 301, 943 (2003). [3] M. 

Weisheit et al., Science 315, 349 (2007). [4] D. Chiba et al., Nature 455, 515 (2008). [5] T. Maruyama et al., Nature Nanotechnol. 

4, 158 (2009). [6] M. Sawicki et al., Nature Phys. 6, 22 (2009). [7] M. Endo et al., Appl. Phys. Lett. 96, 22515 (2010). [8] H. Ohno, 

Nature Mater. 9, 952 (2010). [9] Y. Yamada et al., Science 332, 1065 (2011). [10] D. Chiba et al., Nature Mater. 10, 853 (2011). 

Spin-torque magnetic resonance of superparamagnetic Fe nanoparticles 

in Fe/MgO/Fe magnetic tunnel junctions 

Shinji Miwa, Norikazu Mizuochi, Teruya Shinjo and Yoshishige Suzuki 


During the past decade, electric detection and manipulation of submicron-scale 

magnet have been conducted by using magnetoresistance (MR) effect and spin-torque. 

Now, a great deal of interests in manipulating nano-scale magnets (or single-spin) 

and physics of spin-torque in such a small system are taken. In this study, we employ 

superparamagnetic Fe nano-particles and the single-crystal MgO based magnetic tunnel 

junctions (MTJs) [1]. The magnetic resonance of super-paramagnetic Fe nano-particles 

is electrically excited by spin-torque and detected by the spin-torque diode effect [2,3]. 

The structure of the MTJs is as follows: MgO(100) substrate/Fe film (50 nm)/MgO 

(1.35 nm)/Fe nano-particles (2.1 nm)/capping layer. All of the layers were grown by 

molecular beam epitaxy. The RF detection mechanism is explained as the homodyne 

detection of the applied RF current because of the oscillation of resistance at the same 

frequency. In the measurements, the resonant peak was observed around 5 GHz under 

a magnetic field of 5 kOe at room temperature, for example. This represents that the 

magnetic resonance of superparamagnetic Fe nano-particles was electrically excited and 

detected. We thank Y. Shiota, H. Tomita, G. Shiomi for valuable discussions. This work 

is supported by Grant-in-Aid for Scientific Research (S), MEXT, Japan. (No. 23226001) 

[1] S. Yuasa et al., Nature Mater. 3, 868 (2004). [2] A. A. Tulapurkar et al., Nature 438, 339 (2005). 

[3] S. Ishibashi, S. Miwa et al., submitted. 

Spin Coulomb drag and optical excitations in low dimensional systems 

Irene D'amico 1 and Carsten A. Ullrich 2 

1 Physics, University of York, United Kingdom 

2 Physics, University of Missouri-Columbia, USA 

Within the remit of new quantum technologies, an intense effort is devoted to 

improving our understanding of spin dynamics, with the aim of building novel 

spintronics devices. In this context the theory of spin Coulomb drag (SCD) was 

recently developed. It shows that Coulomb interactions are an intrinsic decay 

mechanism for spin currents. As confirmed by experiments, SCD can be substantial 

in semiconductors, and it is bound to become one of the most serious issues in spin 

polarized transport, since, due to its intrinsic nature, it cannot be avoided even in the 

purest material. More recently the influence of SCD on optical spin-injection and spinresolved 

optical experiments has been considered. Here we report on SCD effects 

on intersubband optical spin excitations in III-V quantum wells, where SCD may 

contribute substantially to the linewidth of spin plasmons. By going beyond the usual 

local density functional approximation and properly including the effects due to the 

inhomogeneity of the system in the growth direction, we show that the quantization of 

states in the growth direction may strongly reduce the intrinsic plasmon linewidth. 


Poster Thursday


RL13 


Perpendicular magnetic property and magnetic damping of very thin 

CoFeB films 

Mikihiko Oogane*, Miho Kubota, Kei Sato, Hiroshi Naganuma and Yasuo Ando 

Applied Physics, Tohoku University, Japan 

A very thin CoFeB film with a perpendicular magnetic anisotropy is a promising material 

for applications of spintronics devices, such as Spin-RAM and spin-logic circuit [1]. 

Development of materials with high magnetic anisotropy and low magnetic damping 

is an important issue to achieve high thermal stability and low power consumption 

in the spintronics devices. However, the relationship between magnetic damping and 

perpendicular anisotropy has not been systematically investigated. In this work, we have 

investigated capping layer dependence of perpendicular magnetic property and magnetic 

damping in very thin CoFeB films. The films were prepared by sputtering system. The 

structure of the films were SiO 2-sub./Ta(5)/MgO(0.9)/CoFeB(d)/X(5 nm), (X = Ta, Pd, 

Cu, Ru, V, MgO). After the deposition of the films, annealing process was carried out at 

250 - 350 o C. Magnetic property and magnetic damping were respectively characterized by 

SQUID and FMR [2]. Perpendicular magnetic anisotropy and damping strongly depends 

on the capping layer material. For the Ta capping layer, CoFeB film below 1.4 nm showed 

a perpendicular anisotropy. However, magnetic damping was drastically enhanced for 

the films with perpendicular anisotropy. Similar behavior was observed in the films with 

capping layers of Pd and Ru. This work was supported by the FIRST program. 

[1] S. Ikeda et al., Nature Material 9, 721 (2010). [2] S. Mizukami et al., Jpn. J. Appl. Phys. 40, 580 (2001). 

RL14 

Perpendicular magnetic tunnel junctions with TbFeCo-based pinned 

layer and CoFeB-MgO free layer 

Jungmin Han 1 *, Byoung-chul Min 1 , Kyung-jin Lee 2 and Kyung-ho Shin 1 

1 

Spin Device Research Center, Korea Institute of Science and Technology, Seoul 136- 

791, Korea 

2 

Department of Materials Science, Korea University, Seoul 136-701, Korea 

We have fabricated perpendicular magnetic tunnel junctions (pMTJs) with a CoFeB/ 

TbFeCo pinned layer and Ta/ CoFeB/ MgO free layer using in-situ annealing 

process. The TbFeCo-based hybrid pinned layer is a useful approach to obtain a high 

perpendicular magnetic anisotropy (PMA). However, a high temperature annealing, 

often required for MgO-based MTJs to obtain a high tunneling magnetoresistance 

(TMR), may deteriorate the PMA of TbFeCo films. Our experimental results show a 

possibility to obtain a reasonable TMR and high PMA simultaneously by conducting 

an annealing process to achieve a grain-to-grain epitaxy in CoFeB/MgO/CoFeB layers 

before depositing the TbFeCo layer. The pMTJs prepared by this process show a 

tunneling magnetoresistance (TMR) ratio of 15% to 19 % at room temperature. 

[1] S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma, H. D. Gan, M. Endo, S. Kanai, J. Hayakawa, F. 

Matsukura & H. Ohno, Nature Materials 9, 721-724 (2010). [2] N. Nishimura,T. Hirai, A. Koganei, 

T. Ikeda, K. Okano, Y. Sekiguchi, and Y. Osada J. Appl. Phys. 91, 5246 (2002). [3] Il-Jae Shin, 

Byoung-Chul Min, Jin Pyo Hong, and Kyung-Ho Shin, Appl. Phys. Lett. 95, 222501 (2009). 

RL15 

Thickness and magnetic anisotropy dependence of anomalous Nernst 

effect in L1 0-FePt films 

Kota Hasegawa, Masaki Mizuguchi*, Ken-ichi Uchida, Eiji Saitoh and Koki 

Takanashi 

Institute for Materials Research (IMR), Tohoku University, Japan 

The anomalous Nernst effect (ANE) is a thermomagnetic effect which gives rise to an 

electric field perpendicular to both temperature gradient and saturation magnetization. 

Although ANE has been known phenomenologically for a long time, only a few 

studies have been reported, and the mechanism has not fully been understood. L1 0- 

FePt with high magnetic anisotropy (K u) attracted much attention for recent years as a 

promising material for “spin caloritronics” [1]. In this paper, we have made systematic 

investigation on the thickness and Ku dependence of ANE in perpendicularly 

magnetized FePt(001) films. FePt(001) films were deposited on MgO(001) single 

crystal substrates at 500°C. The thickness was varied in the range from 7 to 40 nm. 

Ku was changed in the range from 3.0×10 6 to 2.7×10 7 erg/cc, depending on the degree 

of L10 order which was controlled by the deposition temperature from 300 to 500°C. 

It is found that the anomalous Nernst coefficient (Q s) does not depend on the film 

thickness. On the other hand, Qs increases with decreasing K u. These results suggest a 

contribution of spin wave in ANE. 

[1] T. Seki et al., Solid State Comm., Vol. 50, 496 (2010). 


RL16 

Spin-torque efficiency and magnetization reversal in three-dimensional 

Rashba materials 

Kazuhiro Tsutsui and Shuichi Murakami* 

Dept. of Physics, School of Science, Tokyo Institute of Technology, Japan 

In addition to the magnetization reversal by the spin-transfer torque, the magnetization 

reversal driven by a strong spin-orbit coupling has been intensely investigated 

experimentally and theoretically [1,2]. In this presentation, we focus on 3D Rashba 

models coupled with localized spins, and study the spin torque theoretically. This is 

motivated by the recent discovery of BiTeI as 3D Rashba systems [3]. As a result, 

we find that the spin torque in 3D Rashba models is largely enhanced in the highcarrier-density 

regime compared with 2D Rashba models. We also find that the spintorque 

efficiency defined as the ratio between the spin torque and the electric current is 

enhanced when the Fermi energy lies on only lower band, both in 3D and 2D. As we 

change the Rashba spin-orbit coupling, the spin-torque efficiency becomes maximum 

when the Rashba spin-orbit coupling is comparable to the exchange coupling to the 

localized spins. The optimum spin-torque efficiency becomes large when the Rashba 

spin-orbit coupling is large, and it is preferable for the magnetization reversal with 

smaller amount of current injection. 

[1] A. Manchon and S. Zhang, Phys. Rev. B 78, 212405 (2008). [2] I. M. Miron et al., Nature Mater. 

9, 230 (2010). [3] K. Ishizaka et al., Nature Mater. 10, 521 (2011). 

RL17 

A new circuit model for spin-torque oscillator including the 

perpendicular torque of magnetic tunnel junction 

Hyein Lim, Sora Ahn, Miryeon Kim, Jihye Shin, Jinju Lee, Seungjun Lee and 

Hyungsoon Shin* 

Electronic Engineering, Ewha Womans University, Korea 

Spin-torque oscillator (STO) is a promising new technology for the future RF oscillator, which is 

based on the spin transfer torque (STT) effect in magnetic multilayered nanostructure. It is expected 

to overcome the limitations of the semiconductor-based device technology. In our previous work, 

we have proposed a circuit-level model of the Giant Magneto-Resistance (GMR) STO. In this paper, 

we present a physics-based circuit-level model of the Magnetic Tunnel Junction (MTJ)-based STO. 

The new model includes the effect of perpendicular torque that has been ignored in the GMR STO 

model. The variations of three major characteristics, generation frequency, mean oscillation power, 

and generation linewidth of an MTJ STO are investigated by changing the amount of perpendicular 

torque. The model is fully compatible with circuit-level simulators such as SPICE. The accuracy of 

new model was verified by HSPICE simulation. The simulation results show an excellent agreement 

with the experimental data. With our circuit model, we could compose a current mirror circuit that 

contains an STO element and a multi-stage amplifier for signal amplification, such that a full circuitlevel 

simulation of MJT STO was accomplished for the first time. 

1. HyeIn Lim, Sora Ahn, Seungjun Lee, and Hyungsoon Shin: SSDM (2011) p. 1466. 2. A. Slavin, and V. Tiberkevich: IEEE 

Trans. Magn. 45 (2009) 1875. 3. P. Villard, U. Ebels, D. Houssameddine J. Katine, D. Mauri, B. Delaet, P. Vincent, M.-C. Cyrille, B. 

Viala, J.-P. Michel, J. Prouvee, and F. Badets: IEEE J. Solid-State Circuits 45 (2010) 214. 4. Z. M. Zeng, P. Upadhyaya, P. Khalili 

Amiri, K. H. Cheung, J. A. Katine, J. Langer, K. L. Wang, and H. W. Jiang: Appl. Phys. Lett. 99 (2011) 032503. 

RL18 

Current induced localized domain wall oscillators in NiFe /Cu /NiFe 

nano-stripe 

Liang-juan Chang 1 , Pang Lin 2 and Shang-fan Lee 1 * 


2 Department of Materials Science & Engineering, National Chiao Tung University, 

Taiwan 

We study domain wall (DW) oscillations induced by the injection of a dc current through 

a nanowires containing artificial symmetric protrusions with Permalloy based pseudo 

spin valve (NiFe 12 nm/Cu 8 nm/NiFe 24 nm). An experimental analysis was carried out 

to describe the variation of differential resistance dV/dI by applying in-plane dc current 

with pinned DWs. When the DWs are pinned at the traps, we have observed a reversible 

motion of the DWs by changing the applied in-plane dc current. The peak in dV/dI 

associated with the reversible change of magnetoresistance has been taken as evidence of 

current induced coherent DW oscillation between the pinned regimes which gives rise to 

the peak. The excited critical current shifts symmetrically with respect to H. It is expected 

from the DW trap with symmetrical potential landscape. The dynamics of localized DW 

oscillations under application of dc current was examined by micromagnetic simulations 

(OOMMF). The frequency f of DW oscillation decreases from 1.5 GHz to 0.95 GHz as H 

increasing. This simple concept of DW based oscillators could be used as radio frequency 

assisted writing in magnetic recording technology. 

* Corresponding author e-mail: leesf@phys.sinica.edu.tw

RL19 

Current induced transverse field versus Joule heating in Co/Pd 

nanowires 

Mahdi Jamali, Xuepeng Qiu, Kulothungasagaran Narayanapillai and Hyunsoo Yang* 


There has been a tremendous effort in understanding of the electric current effect in 

the ultra thin film of ferromagnetic materials[1, 2]. We have recently found that in the 

nanowire made of a multilayer structure of Co/Pd, there is a current induced transverse 

magnetic field[3]. Electric current could also cause Joule heating especially in the high 

current densities. The Hall resistance has been measured at different current densities 

for the magnetic fields in the easy axis direction. By increasing the current density, 

there is a reduction in the switching field of the nanowire. We further performed the 

measurement at different angles of the magnetic field with respect to the easy axis 

of the sample. From the asymmetry of the switching fields, one can approximate the 

current induced transverse field. Furthermore, by using four-probe measurements, the 

nanowire resistance has been measured at different temperatures and the temperature 

coefficient of the Co/Pd nanowire has been extracted. By measuring the resistance 

of the nanowire at different current densities, we can approximate the nanowire 

temperature during the measurement and its effect on the switching dynamics. 

[1] I. M. Miron, G. Gaudin, S. Auffret, B. Rodmacq, A. Schuhl, S. Pizzini, J. Vogel, and P. 

Gambardella, Nat. Mater. 9, 230 (2010). [2] T. Suzuki, S. Fukami, N. Ishiwata, M. Yamanouchi, 

S. Ikeda, N. Kasai, and H. Ohno, Appl. Phys. Lett. 98, 142505 (2011). [3] K. Narayanapillai, M. 

Jamali, and H. Yang, MMM conference, Arizona (2011). 

RL20 

Improvement of generation efficiency of pure spin current using multiterminal 

spin injection 

Shaojie Hu, Tatsuya Nomura, Seiji Nonoguchi and Takashi Kimura* 

Advanced Electronics Research Division, INAMORI Frontier Research Center, 

Kyushu University., Japan 

Lateral spin valve structures have several advantages for the generation, manipulation 

and injection of the spin current because of their flexible probe configurations. 

Particularly, nonlocal spin injection techniques enable us to create a pure spin current 

which carries the spin information with extremely low propagation loss. However, in 

general, the generation efficiency of the pure spin current is quite low. To solve this 

serious obstacle, we propose a nonlocal spin injection with multi spin injectors. In 

the present study, we fabricated the lateral valve structure consisting of a quadruple 

Permalloy spin injectors and nonmagnetic Cu strip and show that the developed device 

has two advantages. One is that the maximum generated spin current is strongly 

enhanced. The other one is that the efficiency for generating a certain quantity of the 

spin current is significantly improved. We also show that the optimization of the device 

dimension yields the further enhancement of the maximum generating spin current. 

M. Johnson and R. H. Silsbee, Phys. Rev. Lett. 55, 1790 (1985). T. Kimura, T. Sato, and Y. Otani, 

Phys. Rev. Lett. 100, 066602 (2008). T. Kimura et al., Appl. Phys. Lett. 85, 3501 (2004). 

RL21 

Electrical transport properties of Co2MnSi Schottky diode 

In-bok Baek 1 , Xianhong Li 1 , Seongjae Lee 1 *, Chil Seong Ah 2 , Jong-heon Yang 2 , Chan 

Woo Park 2 , Han Young Yu 2 , Moongyu Jang 2 and Gun Yong Sung 2 

1 

Department of Physics, Research Institute for Natural Sciences,, Hanyang University, 

Seoul, 133-791,, Korea 

2 

Electronics and Telecommunications Research Institute (ETRI), Daejon, 305-700,, Korea 

Recently, the spintronic device has attracted considerable attentions due to its possibility to lead a new 

generation of electronic devices by utilizing spin degree-of-freedom. Especially, silicon is a very attractive 

material for the spin channel of spintronic devices due to a weak spin-orbit coupling [1] and a long spin 

lifetime of ~ 10 ns [2, 3], while Co 2MnSi being a half-metallic Heusler compound is regarded as a promising 

candidate for the spin injection/detection electrodes due to a possible complete spin polarization. [4, 5] In this 

work, the electonic transport chracteristics of Co 2MnSi/Si Schottky diodes are studied for the investigation of 

spin electrode/channel interface quality, in which Co 2MnSi was prepared under various process conditions. 

We found that the Schottky barrier height of Co 2MnSi decreased from 0.56 to 0.52 eV and 0.44 to 0.36 eV 

for electron and hole, respectively, with increasing RTA temperature from 450 to 550°C. Also, the ideality 

factor close to unity for RTA temperature of 450°C significantly degraded as it changed to 550°C, indicating 

the increase of interface trap density. Deduced from our electrical results, the manufactured Co 2MnSi is 

expected as a promising ferromagnetic material for the applications in silicon spintronic devices. 

[1] I. Zutic, J. Fabian, and S. C. Erwin, Phys. Rev. Lett. 97, 026602 (2006). [2] G. Lancaster, J. A. V. Wyk and E. E. 

Schneider, Proc. Phys. Soc. London 84, 19 (1964). [3] J. Fabian, A. Mathos-Abiague, C. Ertler, P. Stano, and I. Zutic, 

Acta Phys. Slov. 57, 565 (2007). [4] Y.ohdaira, M. Oogane, H. Naganuma, and Y. Ando Appl. Phys. Lett. 99, 132513 

(2011). [5] P. J. Brown, K. U. Neumann, P. J. Webster and K. R. A. Ziebeck, J. Phys.: Condens. Matter 12, 1827 (2000). 

RL22 

RL23 

RL24 


Negative electron-beam resist hard mask ion beam etching process for 

the fabrication of nanoscale spin transfer torque magnetic random 

access memory device 

Hyungyu Lee 1 , Daehong Kim 1 , Bongho Kim 1 , Sungwoo Chun 1 , Seonjun Choi 1 and 


1 Department of Electronic Engineering, Hanyang University, Korea 

2 Institute of Nano Science and Technology, Hanyang University, Korea 

To conduct MTJs etching process, Ta[1] hard masks are generally used for reactive 

ion etching and ion beam etching (IBE) process due to relatively good selectivity over 

magnetic metals. However, tapering of the Ta mask is unavoidable which results in the 

underlying MTJ to become trapezoidal. Here we utilized negative electron-beam resist 

(NER) hard mask process to overcome the hard mask induced nano-patterning difficulties. 

Arrays of 30 nm dot patterns 200 nm apart were defined by electron beam lithography 

with a NER thickness of 90 nm. The IBE was performed using the NER as the hard mask 

layer. During the IBE process, The IBE etch rate of the NER was 3 nm/min and since the 

total MTJ etching thickness was 36 nm with 2.1 nm/min etch rate, a 30 nm diameter NER 

pillar with 90 nm thickness was enough to produce the 30 nm diameter MTJ nanopillars. 

And redeposition of the etched material on side walls of the NER protects the resist from 

tapering, resulting in vertical side profiles in the etched MTJs. 

[1] X. Peng, S. Wakeham, A. Morrone, S. Axdal, M. Feldbaum, J. Hwu, T. Boonstra, Y. Chen, J. 

Ding, Vacuum. 83. 1007 (2009) 

Magnetization reversal process of a Py nanodot under pure spin 

current injection 

Tatsuya Nomura, Seiji Nonoguchi and Takashi Kimura* 

Kyushu University, Japan 

A new type lateral spin valve structure based on a pair of closely located Permalloy 

nanopillars has been developed. This structure enables us to flow a large amount of 

current, resulting in the injection of a large pure spin current into a ferromagentic 

nanodot entirely. We investigated the magnetization reversal process of the Permalloy 

nanodot under dc pure spin current injection from the field dependence of the nonlocal 

spin valve signal. The dc pure spin current was generated by flowing the dc current 

with an ac excitation current in the nonlocal current terminal. The nonlocal spin valve 

signal without the dc current exhibits a clear bipolar signal typically observed in the 

conventional lateral spin valve.[1,2] The nonlocal signal curve shows the systematic 

changes with increasing the dc pure spin current and its variation strongly depends on 

the current intensity and polarity. This means that the reversal process of the Py dot is 

strongly modified by the pure spin current injection. 

[1] F.J.Jedema,A.T.Filip,B.J.vanWees,Nature410(2001)345. [2] T. Kimura et al. Appl. Phys. Lett. 

85, 3501~3503 (2004) 

Spin transfer effect in FePt nanowires: controlling the stochasticity of 

domain wall depinning using constrictions 

Jean-philippe Attane 1 , Van Dai Nguyen 1 , Alain Marty 1 , Lucien Notin 1 , Cyrille Beigne 1 , 

Juan Carlos Rojas-sanchez 1 , Stefania Pizzini 2 and Laurent Vila 1 

1 

Universite Joseph Fourier, BP 53, 38041, Grenoble and INAC/ CEA Grenoble, 17 

avenue des Martyrs, France 

2 

Institut Neel, CNRS, 25 avenue des Martyrs, 38042 Grenoble, France 

In this contribution, we present dynamic measurements of domain wall (DW) depinning from structural 

defects, in nanowires processed from single FePt layers and FePt/Pd(Pt)/FePt spin-valves. Statistical 

analysis reveals that in such systems, the DW depinning is stochastic, and that this stochasticity has two 

origins. The first one is thermal activation, which helps the wall to cross the energy barrier associated 

to the defect. The second one originates from the ability of the DW to get pinned randomly along 

different micromagnetic configurations, each one corresponding to a given depinning fields. We study 

the influence of different constriction types on the dynamic of DW depinning, using spin-valve-based 

nanowires. The depinning probability function is found to exhibit very different behaviors, which depend 

on the types of constriction: it is partially possible to control the stochastic behavior of DW depinning by 

tuning the shape of constrictions. Additionally, we showed that the probability function of DW depinning 

can be varied by applying a DC current, the effect of the spin torque on thermal and configurational 

stochasticities being similar to those of a field. The measured spin transfer torque efficiency is very high 

(~10-13T.m 2A -1 ), and is similar for single FePt layers and FePt-based spin-valves. 

C. Burrowes et al., Nat. Phys. 6, 17 (2010) A. Mihai et al., Phys. Rev. B 84, 014411 (2011) 


Poster Thursday


RL25 


Electric field effect on magnetic coercivity of Fe3O4/BaTiO3 


Tomoyasu Taniyama*, Taiichiro Nozaki, Yasuhiro Shirahata, Gorige Venkataiah and 

Mitsuru Itoh 


Electric field control of the magnetic coercivity of half metallic Fe 3O 4 epitaxial thin films 

on BaTiO 3(001) is demonstrated at room temperature, with a view to developing a new 

type of highly spin polarized electron source, where the magnetization orientation of the 

spin source can be controlled by electric field. Fe 3O 4 films were grown on BaTiO 3(001) 

substrates by reactive molecular beam epitaxy in an oxygen atmosphere at a pressure of 

1×10 -6 Torr. The Fe 3O 4 films show a clear Verwey transition at ~120 K, ensuing the high 

quality of the films grown. The electric field variation of the in-plane magnetic coercivity 

of Fe 3O 4 films was measured using Kerr effect, exhibiting a hysteretic behavior, where the 

magnetic coercivities for positive and negative electric fields at ±10 kV/cm show distinct 

values. Since a possible strain effect due to ferroelectric domain switching of BaTiO 3 

should be equivalent for both electric field polarities over the switching field, another 

possible mechanism such as polarization charge accumulation at the interface likely has 

its origin in the electric field effect, associated with carrier induced modulation of the 

electronic states of Fe 3O 4. Work supported in part by Industrial Technology Research 

Grant Program in 2009 from NEDO, Japan. 

[1] G. Venkataiah, Y. Shirahata, M. Itoh, and T. Taniyama, Appl. Phys. Lett. 99, 102506 (2011). 

RL26 

Dependence of current-induced effective rashba field and 

perpendicular magnetic anisotropy on annealing temperature 

Ki-seung Lee 1 , Byung Chul Min 1 , Kyung Jin Lee 2 * and Kyung-ho Shin 1 

1 

Spin Convergence Research Center, Korea Institute of Science and Technology, 

Korea 

2 

Departments of Materials Science and Engineering, Korea University, Korea 

Manipulation of local magnetization using electrical current has attracted considerable interest 

due to its rich physics and potential applications for a new class of spintronic devices. It was 

theoretically proposed that Rashba-type spin-orbit coupling (SOC) caused by inversion symmetry 

breaking yields a new type of current-induced effective magnetic field [1], i.e. Rashba field of 

which direction is perpendicular to both the direction of current-flow and that of the inversion 

symmetry breaking. The existence of this Rashba field in the structure consisting of non-magnetic 

metal | ferromagnetic metal | oxide was recently confirmed experimentally [2]. We previously 

investigated the effect of the ferromagnetic film thickness on the Rashba spin transfer torque 

(STT), as well as its effect on the perpendicular magnetic anisotropy. The magnetic anisotropy 

clearly showed surface properties, while the surface nature of the Rashba field remained elusive. 

In this work, we further investigate the dependence of current-induced effective Rashba field and 

perpendicular magnetic anisotropy on annealing temperature. Experiments were carried out on 

Pt(3nm)|Co(0.6nm)|MgO(2nm) samples with the annealing temperature from 300 O C up to 450 

O C. In this presentation, the effect of annealing treatment will be discussed. 

[1] A. Manchon and S. Zhang, Phy. Rev. B 78, 212405 (2008) ; Phys. Rev. B 79, 094422 (2009). [2] I. 

M. Miron et al., Nature Mater. 9, 230 (2010). 

RL27 

Spin motive force driven by magnetization dynamics 

Junichiro Ohe 

Toho University, Japan 

The current-induced magnetization dynamics realized in spintronics devices involve 

both of charge and spin degrees of freedom. Recently, it has been pointed out that the 

magnetization dynamics induces an effective electric field acting on the conduction 

electrons through the spin Berry phase. The effective electric field, or a 'spin motive 

electric field', was investigated for a simple one-dimensional domain wall. It is 

difficult to estimate analytically this effective electric field in actual systems, because 

the magnetization dynamics obeys the non-linear Landau-Lifshitz equation. In this 

report, we investigate the the spin motive force and the measurable voltage by solving 

Landau-Lifshitz-Gilbert equation numerically. We propose several structures that 

show measurable spin motive force. We also compare the our numerical results and 

experimental results. 

J. Ohe and S. Maekawa, J. Appl. Phys. 105, 07C706 (2008) J. Ohe et al., Appl. Phys. Lett., 95, 

123110 (2009) Y. Yamane et al, Phys. Rev. Lett. 107, 236602 (2011) M. Hayashi et al, Phys. Rev. 

Lett. (2012) in press 


RL28 

Electrical detection of the spin Hall effects in the InAs quantum well 

structure 

Tae Young Lee, Joonyeon Chang*, Hyun Cheol Koo, Hyung-jun Kim and Suk Hee 

Han 

Korea Institute of Science and technology, Korea 

Spin Hall effect (SHE) becomes intriguing because it generates and manipulates carrier 

spins in non-magnets without external magnetic field. Use of perpendicularly polarized 

spin currents for spin field effect transistor is a quite promising because precession of 

perpendicularly polarized spins can be manipulated by Rashba spin orbit coupling in the 

absence of the applied field along momentum direction [1]. The SHEs are electrically 

measured for an InAs quantum well (QW) structure where Rashba field of 8.5 Tesla 

is induced. The device is composed of an InAs channel and Pd/CoFe multilayers with 

perpendicular magnetization, which allows to detection of spin Hall voltages. The spinpolarized 

electrons with perpendicular orientation cause a charge accumulation at the 

edge of the InAs channel probed by spin Hall voltage. This charge accumulation induces a 

transverse voltage. We observe large spin Hall resistance up to 9.3 mΩ and spin Hall angle 

is found to be about 0.01. According to the theoretical reports [2, 3], one of its origins is 

spin-orbit scattering of conduction electrons through side-jump or skew scattering. The 

SHEs are emerging from the side-jump scattering of flowing spins in the InAs QW and the 

scattering direction is determined by spin orientation with spontaneous magnetization. 

REFERENCES [1] Koo et al., Science. 325, 1515 (2009). [2] J. E Hirsch, Phys. Rev. Lett. 83, 1834 

(1999). [3] J. Zhang, Phys. Rev. Lett. 85, 393 (2000). 

RL29 

Bias-voltage controlled tunneling resistance in a ferromagnet-metalinsulator-ferromagnet 

tunneling junction 

Sui-pin Chen* 

Department of Electrophysics, National Chiayi University, Taiwan 

We adopt the spin-polarized free-electron model [1-3] and extend our previous work [4] 

to study the tunneling resistance change in a ferromagnet/metal/insulator/ferromagnet 

magnetic tunneling junction [5], and find a method for changing the tunneling 

resistance. Unlike the traditional method of varying the magnetizations configuration 

between the two ferromagnetic layers, the proposed method uses the polarity of a 

bias voltage with a small strength to change the tunneling resistance. Under suitable 

conditions, we show that both tunneling resistance changes resulting from the polarity 

of the bias voltage and from the magnetizations configuration are equal in magnitude, 

and are larger than that in a conventional ferromagnet/insulator/ferromagnet magnetic 

tunneling junction. 

[1] S. Zhang and P. M. Levy, Phys. Rev. Lett. 81, 5660 (1998). [2]J. Yang, J. Wang, Z. M. Zheng, D. 

Y. Xing and C. R. Chang, Phys. Rev. B 71, 214434 (2005). [3] S.-P. Chen and C.-R. Chang, IEEE 

Trans. Magn. 45, 2410 (2009). [4] S.-P. Chen, J. Appl. Phys. 107, 09C716 (2010). [5] S. Yuasa, T. 

Nagahama and Y. Suzuki, Science 297, 234 (2002). 

RL30 

A highly (001) textured Ge/MgO/bcc-ferromagnet system prepared by 

ultra-high vacuum sputtering 

Soogil Lee 1 , Sanghoon Kim 1 , Jungho Ko 1 , Sangho Lee 1 , Jangyup Son 1 , Seung-heon 

Chris Baek 2 , Seok-hee Lee 2 and Jongill Hong 1 * 

1 Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea, Korea 

2 Dept. of Electrical Engineering, Korea Advanced Institute of Science and Technology 

(KAIST), Daejeon, 305-701, Korea, Korea 

Observation of spin accumulation in semiconductor is very fascinating for fundamental physics and applications 

as well. Many important progresses have recently been made in this field. For example, the insertion of a tunnel 

barrier at the interface between ferromagnet (FM) and semiconductor has increased the chemical potential 

difference at the interface [1]. Ge/MgO/bcc-FM has been intensively studied because of an epitaxial growth of 

MgO on a Ge substrate due to small lattice mismatch (~4%) between Ge(001)[100] and MgO(001)[110]. As 

a result, the symmetry-related spin-dependent tunneling is expected to occur at the Ge/MgO/bcc-FM junction. 

The successful growth of the single-crystal Ge(001)/MgO(001)/bcc-FM(001) stack has been reported [2,3]. 

However, these results have been obtained using a molecular beam epitaxy technique which may not be 

suitable for applications in the industry. Here, we show that a highly (001) textured Ge/MgO/CoFeB junction 

can be achieved by an ultra-high vacuum sputtering technique. We will discuss the effect of various deposition 

conditions on the (001) texture of MgO/CoFeB deposited on (001) Ge. The quantitative and qualitative analyses 

of the structures of MgO/CoFeB layers will be presented based on the results of x-ray diffractometry and 

transmission electron microscopy. Finally, we will examine the tunneling characteristics of the junction. 

[1] Abert Fert and Henry Jaffres, Physical Review B 64, 184420 (2001) [2] Wei Han, et al., Journal of 

Crystal Growth 312, 44 (2009) [3] Kun-Rok Jeon, et al., Crystal Growth and Design 10, 1346 (2010)

RL31 

Electrical spin injection and detection in GaAs with ferromagnetic 

metal/MgO junctions 

Seong Hoon Shim 1 , Kyung-ho Kim 1 , Hyung-jun Kim 1 , Yun-hi Lee 2 and Joonyeon 

Chang 1 * 

1 

Spin Convergence Research Center, Korea Institute of Science and Technology, 

Korea 

2 

Department of Physics, Korea University, Korea 

The intrinsic conductance mismatch between ferromagnetic metals (FM) and 

semiconductors is a critical obstacle in spin injection, and inserting a thin tunnel 

barrier, especially MgO, is expected to hurdle this problem. [1] In this study, we report 

electrical measurements of spin polarization in GaAs coming from efficient spin 

injection through MgO tunneling barrier. The whole epitaxial layers of FM/MgO/GaAs 

structures were prepared in-situ process using cluster MBE. To reduce the depletion 

layer of Schottky barrier, doping modulated GaAs layer has been inserted in the 

vicinity of the interface between GaAs and MgO layers. Large voltage drop (ΔV = 6.3 

mV at 10 K when I = -0.9 mA in Fe/MgO/GaAs structure) between the baseline and 

the dip of Hanle curve is observed at various temperatures up to 400 K in a 3-terminal 

Hanle measurement geometry. The Lorentzian fitting of the Hanle curve gives 234 ps 

spin lifetime of n-doped GaAs and 952 nm spin diffusion length at 300 K. 

[1] G. Schmidt, D. Ferrand, L.W. Molenkamp, A.T. Filip and B.J. van WeesPhys. Rev. B 62, R4790 

(2000). 

RL32 

Transistorless 3D STT-MRAM Architecture 

Weizhong Wang* 

University of Wisconsin - Milwaukee, USA 

The MTJ based devices are fabricated through thin film deposition and patterning 

which are intrinsically capable for 3D vertical multiple layers integration. However, 

current MRAM architecture requires at least one isolation transistor in each MRAM 

cell(1). Since there is no mature 3D CMOS technology available, isolation transistor 

prevent the progress on developing 3D MRAM. Therefore the races on MRAM area 

density improvements are all based on aggressive horizontal cell size scaling. This 

paper introduces a new transistor-less MRAM architecture to enable vertical 3-D 

integration. Since the MTJ devices are essentially two terminal resistors, an array 

of MTJ devices form a connected resistor network. We introduce a 3D architecture 

with new read/write operation to address individual MTJ cells. Comparing with 

conventional STT-MTJs, our preliminary simulation results show (1) little penalties on 

both speed and power consumption during read operation;(2) little penalty on writing 

speed; and (3) 2x to 3x penalty on writing power consumption depending on TMR ratio 

of MTJs. The proposed STT-MRAM architecture can greatly enhance the area density 

of STT-MRAM and beat CMOS or any single layer based memory technologies. 

(1) Tehrani, S.; Slaughter, J.M.; Deherrera, M.; Engel, B.N.; Rizzo, N.D.; Salter, J.; Durlam, M.; 

Dave, R.W.; Janesky, J.; Butcher, B.; Smith, K.; Grynkewich, G.; 'Magnetoresistive random access 

memory using magnetic tunnel junctions', Proceedings of the IEEE, Volume: 91 , Issue: 5, 2003 , 

pp.703 - 714 

RM01 

Collision of cobalt atom with Alq3 molecule thin film: a molecule 

dynamics study 

Yun-peng Wang, Ling-ling Tao and Xiu-feng Han* 

Institute of Physics, Chinese Academy of Sciences, China 

Yun-Peng Wang, Xiu-Feng Han and Ling-Ling Tao Beijing National Laboratory 

of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, 

Beijing 100190, China Hai-Ping Cheng Department of Physics and Quantum Theory 

Project, University of Florida, Gainesville, Florida 32611, USA Molecular dynamics 

simulations on deposition of cobalt atom onto tris(8-hydroxyquinoline) aluminum 

(Alq3) molecule thin film are presented. A Lennard-Jones potential calibrated by firstprinciple 

calculations was used to describe Alq3-Co interactions. Microscopic collision 

process was analyzed by looking into one trajectory. Statistics of final positions and 

penetration depths of cobalt atoms show that cobalt atoms with low initial energy 

penetrate little into Alq3 thin film and stay near the surface of Alq3 thin film while 

cobalt atom with high initial energy penetrates significantly into Alq3 thin film. 

Consequently, thickness of Alq3/cobalt interface is equal to roughness of Alq3 surface 

if initial energies of cobalt atoms are small, but 1 nanometer larger than roughness of 

Alq3 thin film if initial energies of cobalt atoms are large. Injected cobalt atoms lose 

their kinetic energies via collision with 8-hydroxyquinoline ligands of Alq3 molecules. 

DFT calculations show hybridization of carbon and oxygen due to cobalt and sizable 

charge transferred from cobalt to nearest Alq3 molecule. 

RM02 

RM03 

RM04 


Magnetism and Electronic Structures of SiC nanoribbons: Role of 

defects 

Gul Rahman 1 * and J. M. Morbec 2 

1 Department of Physics, Quaid-i-Azam University,Islamabad, Pakistan 

2 Instituto de Ciencias Exatas, Universidade Federal de Alfenas, 37130-000, Alfenas, 

MG, Brazil, Brazil 

Magnetism in diamagnetic materials such as defective SnO2, ZnO, or SiC got 

particular attention to probe and understand the source and nature of magnetism in 

these materials. Particularly, the role of intrinsic defects, e.g. a vacancy which is the 

main source of magnetism, motivated many scientists around the world. The defect 

formation energies of vacancies in these diamagnetic materials are very large which 

limit its experimental synthesis. Here, we focused on SiC nanoribbons (NRs) to probe 

the native defects and their interacations with the alien light element impurities, e.g., 

B, N, in terms of magnetism. Using ab-initio calculations based on density-functional 

theory (DFT), our extensive results indicate that silicon or carbon vacancy per cell 

induces magnetic moment in SiCNRs, whereas SiCNR with Si+Si divacancy has 

almost zero magnetic moment. The half-metallic behavior, which is very important for 

spintronics devices, of SiC NRs is maintained in the presence of one C or Si vacancy 

per cell. The Si or C vacancies have high defect formation energies, howevere, we 

found that foreing impurities B or N significantly reduced the defect formation energy 

of vacancies in SiCNRs. 

Bulk and surface half-metallic ferromagnetism in transition-metal 

chalcogenides with rocksalt phase from first-principles calculations 

Guoying Gao* and Kailun Yao 

School of Physics, Huazhong University of Science and Technology, China 

In the past decade, most of transition-metal pnictides and chalcogenides with metastable zincblende 

structure were predicted to be half-metallic ferromagnets. So far, however, only four of 

them, zinc-blende CrAs, MnAs, CrSb, and CrTe, have been realized experimentally in the form 

of thin films or multilayers because of the instability of the zinc-blende phase. Here we predict 

with first-principles calculations that all three rocksalt CrTe, VPo, and CrPo are half-metallic 

ferromagnets with the half-metallic gaps of 0.03, 0.18, and 0.31 eV, respectively. Importantly, 

the rocksalt phases are approximately 0.19-0.33 eV per formula unit lower in energy than the 

corresponding zinc-blende phases for these three half-metallic compounds, which indicate it is 

more possible to fabricate these binary compounds with rocksalt phase than the zinc-blende phase 

in the form of thin films or multilayers. We also study the (111) surface properties of rocksalt CrTe 

and CrPo, and find the Te- (Po-)terminated (111) surface is more stable than the Cr-terminated (111) 

surface, and both Cr- and Te- (Po-)terminated (111) surfaces preserve the bulk half-metallicity. 

The present work will not only add to the understanding of these binary half-metals, but will also 

stimulate experimental efforts toward fabrication and utilization of these systems in spintronics. 

[1] T. Graf, C. Felsler, and S. P. P. Parkin, Prog. Solid State Chem. 39, 1 (2011). [2] C. Felser, G. H. Fecher, and B. Balke, 

Angew. Chem. Int. Edn 46, 668 (2007). [3] M. I. Katsnelson, et al., Rev. Mod. Phys. 80, 315 (2008). [4] S. K. Bose and J. 

J. Kudrnovsky, Phys. Rev. B 81, 054446 (2010). [5] G. Y. Gao and K. L. Yao, Appl. Phys. Lett. 91, 082512 (2007). [6] J. J. 

Deng, et al., J. Appl. Phys. 99, 093902 (2006). [7] G.Y. Gao, K.L. Yao, N. Li, J. Phys.:Condens. Matter 23, 075501 (2011). 

Magneto-transport properties of Fe thin films in an external electric 

field 

Kohji Nakamura 1 *, T. Akiyama 1 , T. Ito1, M. Weinert 2 and A. J. Freemnan 3 

1 Physics Engineering, Mie University, Japan 

2 Physics, University of Wisconsin-Milwaukee, USA 

3 Physics and Astronomy, Northwestern University, USA 

UPGRADED 


Poster Thursday



RM05 

Role of interfacial B impurity in magnetocrystalline anisotropy at 

MgO/Fe interface 

Koji Hotta*, Kohji Nakamura, Toru Akiyama and Tomonori Ito 

Mie University, Japan 

An interface induced-perpendicular magnetocrystalline anisotropy (MA), as observed 

in the MgO/CoFeB,[1] has attracted much attention in magnetic application. From 

first-principles, previously, we demonstrated a perpendicular MA at the MgO/Fe 

interface due to a weak Fe d_z-O p_z hybridization[2], but it still need to discuss a 

role of interfacial B impurity. Here, we extend investigation to include the interfacial B 

impurity. Calculations were carried out by using FLAPW method[2]. First, the phase 

stability at the MgO/Fe interface was determined based on calculated total energy with 

a model of an MgO monolayer on a five-layer Fe, where the B were incorporated in 

interstitial positions at top, second, and third Fe-interface-layers. Results indicate that 

the B favors to segregate to the interface so as to form an MgO/FeB/Fe interface. Then, 

the MA energy (E_(MA)) was calculated by using the second variation SOC method 

and the force theorem. The calculated E_(MA) has a large positive value of 0.69 eV for 

the ideal MgO/Fe, indicating a perpendicular MA. For the MgO/FeB/Fe, the E_(MA) 

turns out to be almost zero (-0.02 eV), which indicates no interface MA, due to an 

enlargement of the Fe-MgO interlayer distance by the interfacial B atoms. 

[1] S. Ikeda, et.al. , Nature Mater. 9, 721 (2010) . [2] K. Nakamura, et.al. , Phys. Rev. B81, 220409 

(2010) . 

RM06 

First-principles study on magnetic anisotropy of Co/Pt(111) film in 

electric field 

Sho Yasuda* and Shugo Suzuki 

Division of Materials Science, Faculty of Pure and Applied Sciences, University of 

Tsukuba, Japan 

Electric field (EF) control of magnetism is attractive for spintronics devices. In 

recent research, it has been shown that EF affects not only magnetic moment but also 

spin conduction and magnetic anisotropy[1-4]. In particular, it has been found that 

combination of the 3d and 5d metals in EF causes large effects on magnetic anisotropy. 

In this study, we investigate the dependence of the magnetic anisotropy energy (MAE) 

and the magnetic moment of Co/Pt(111) on EF by first-principles calculations. We 

employ the fully relativistic full-potential linear-combination-of-atomic-orbitals method 

based on the density-functional theory within the local-spin-density approximation. 

The exchange-correlation energy functional is the Perdew-Wang parameterization of 

the Ceperley-Alder results. We have found that the magnetic moment of the Co atom 

is in proportion to EF. The results of the calculations of the MAE and the other details 

will be shown at the conference. 

[1]T. Maruyama, Y, Shiota, T. Nozaki, K. Ohta, N. Toda, M. Mizuguchi, A. Tulapurkar, T. Shinjo, M. 

Shiraishi, S. Mizukami, Y. Ando and Y. Suzuki: Nature. Vol.4 (2008) 158 [2]D. Chiba, S. Fukami, 

K. Shimamura, N. Ishiwata, K. Kobayashi, and T. Ono: Nature Mater. Vol.10 (2011) 853. [3]M. 

Tsujikawa and T. Oda: Phys. Rev. Lett. Vol.102 (2009) 247203. [4]K. Nakamura, T. Akiyama, and T. 

Ito: Phys. Rev. B Vol.81 (2010) 220409. 

RM07 

Magnetic ground state of TM/Graphene/TM films 

Dongyoo Kim, Arqum Hashmi and Jisang Hong* 

Department of Physics, Pukyong National University, Korea 

Using the full potential linearized augmented plane wave (FLAPW) method, we have 

investigated the magnetic properties of transition metal (TM)/Graphene/transition 

metal (TM) structure. We have explored magnetic properties of metal/grapheme/ 

metla systems, which is Co(1 ML)/Graphene/Ni(1 ML). Co(1ML)/Graphen/Ni(1ML) 

film have the AFM ground state. The calculated magnetic moment of Ni is -0.22 μB, 

while the Co layer has 1.50 μB. In calculation of optimized structure, we have that 

the distance between carbon and Co is 2.07 A and it is 2.04 A for carbon and Ni. The 

relative height difference between two carbon atoms in grapheme layer is 0.29 A. 

To understand the effect of buckling geometry of graphene, we have performed the 

calculation whithout any buckling factor of graphene layer. The magnetic ground state 

is not changed, and calculated magnetic moment of Ni and Co are -0.60 and 1.70, 

respectively. This implies that the AFM coupling is an intrinsic property of Co(1ML)/ 

Gr/Ni(1ML) system. Also, we will present the magnetic properties of Co(2ML)/Gr/ 

Ni(1ML) and Co(1ML)/Gr/Ni(2ML) systems. This work was supported by KCAP 

located in Sogang University funded by the Ministry of Education, Science, and 

Technology (MEST) through the National Research Foundation of Korea (NRF-2011- 

C1AAA001-2011-0030278) and by KOSEF (No. R01-2008-000-20014-0). 


RM08 

A model of chain of ellipsoid-rings for magnetic nanotubes 

Sen Yang*, Junfeng Gong and Xiaoping Song 

Department of Materials Physics, Xi'an Jiaotong University, China 

Numerical calculation of magnetic properties is a very effective way to understand the 

whole magnetic behavior of nanotubes. Currently, the most studies of calculation of 

magnetic properties of nanotubes are mainly grounded on the Stoner-Wohlfarth (S-W) 

model, starting from an elongated prolate ellipsoid with single-domain. But, it is hard 

to imagine how such an ellipsoid is arranged in the hollow tubular structure and hence 

the realization of predicted magnetic properties has been hindered by the experimental 

difficulties. In the present article, an alternative model of chain of ellipsoid-rings is 

proposed to calculate the magnetic properties of nanotubes, where the chain of rings 

with ellipsoid particles is assumed to compose nanotube. Based on this new model, 

we calculate the magnetic properties of nanotube and further discuss the influence 

of tubular geometric parameters on the magnetic properties. All the results are well 

consistent with the experimental data of Ni nanotube and moreover are available for 

the Ni nanowire. Consequently, our model provides an easy and general approach to 

both magnetic nanotubes and magnetic nanowires. 

RM09 

First-principles GGA+U calulations of half-metallicity in wurtzite 

NiO/ZnO(0001) superlattices 

X. H. Zhou 

National Laboratory for Infrared Physics,, Shanghai Institute of Technical Physics, 

Chinese Academy of Sciences, China 

Wurtzite NiO has been predicted to display half-metallicity and have only small 

lattice mismatch with wutzite ZnO [1]. It is interested to explore the possibillity of 

the so-called all oxides spintronics obtained by the hybrid structrues consisted of the 

wurtize NiO and ZnO [2]. In this contribution, the structural, electronic, and magnetic 

properties of wurtzite NiO/ZnO(0001) superlattice were investigated by means of 

density functional calculations using spin-polarized generalized gradient approximation 

GGA and GGA+U schemes. We demonstrate that these superlattices retain their halfmetallic 

behavior leading to a complete, i.e., 100%, spin polarization of the conduction 

electrons.This property makes the wurtzite NiO/ZnO(0001) heterostructures to be 

excellent candidates for high-efficiency magnetoelectronic devices. 

[1] R. Q. Wu, G. W. Peng, L. Liu, and Y. P. Feng, Appl. Phys. Lett. 89, 082504 (2006) [2] Z. Chen, L. 

Miao, and X. Miao, AIP ADVANCES 1,022124 (2011) 

RN01 

Magnetic properties of La doped nanocrystalline Z-type ferrite 

nanopowders synthesized via co-precipitation method 

Mohamed M. Rashad 1 *, M. Rasly 1 , H. M. Elsayed 2 , A. A. Satter 2 and I. A. Ibrahim 1 

1 

Advanced Materials Department, Central Metallurgical Research and Development 

Institute, Egypt 

2 

Physics Department, Ain Shams University, Egypt 

Co2Z type hexagonal ferrites powders doped with La 3+ ions (Ba 3-XLaXCo 2Fe 24O 41 

where X=0.0, 0.05, 0.10 and 0.15) were prepared using co-precipitation method. The 

results revealed that single phase CO2Z type ferrite was formed from the precipitated 

precursor in presence of SDS as anionic surfactant and then preheated at 600oC 

for 4h and then post annealed at 1300oC for 6h. Moreover, the crystallite size and 

the porosity,% of the formed powders were increased whereas the unit cell volume 

were decreased by increasing the La 3+ substitution. The microstructure of the formed 

powders appeared as hexagonal platelet like structure. The DC resistivity of the 

obtained CO2Z was decreased as La 3+ content increased. The saturation magnetization 

(Ms= 53.7-55.5 emu/g) was slightly increased with substitution of La 3+ . Moreover, 

two resonance frequencies peaks are observed through the imaginary part of complex 

permeability meanwhile a decrease in the real part of magnetic permeability through 

X-band frequencies. The reasons are discussed using electromagnetic theory. 

1- G. Shihai, Z. Yanghuan, F. Zekun, W. Xinlin, H. Huahui, J. Rare Earths 25(2007)220-225 2-X.Wang, L. Li, S. Su, Z. 

Gui, Z. Yue, J. Zhou, J. Eur. Ceram. Soc. 23(2003)715-720. 3- J. J. Xu, C. M. Yang, H. F. Zou, Y. H. Song, G. M. Gao, B.C. 

An, S. C. Gan, J. Magn. Magn. Mater. 321(2009)3231-3235. 4-L. Qin, H. Verweij, Mater. Lett. 68(2012)143-145.

RN02 

Magnetic properties of Fe-doped NiO nanoparticles 

Akinobu Kurokawa*, Takuya Yanoh, Shinya Yano, Hiromasa Takeuchi, Kazuki 

Onuma, Takaya Kondo, Kazunari Miike, Toshiki Miyasaka and Yuko Ichiyanagi 

Physics, Yokohama National University, Japan 

NiO is known as a P-type semiconductor with wide band gap between 3.2 eV and 

3.5 eV, and expected as a new material of diluted magnetic semiconductor. Magnetic 

properties of NiO nanoparticles with several nanometers were observed and blocking 

temperature(TB) was determined to be 17 K, while Neel temperature of NiO bulk 

crystal exhibits TN=523 K. In this study, Fe ions were doped into NiO nanoparticles in 

order to obtain higher blocking temperature. Ni1-xFexO (x=0, 0.05, 0.1) nanoparticles 

with several nanometers encapsulated with amorphous SiO 2 were prepared by our 

novel preparation method. NiO single phase structure was confirmed from the x-ray 

diffraction measurements. It is considered that Ni ions are replaced to Fe ions exactly. 

This fact was also supported by X-ray absorption fine structure measurements. 

Magnetization measurements were performed by SQUID magnetometer for obtained 

samples. Temperature dependence of magnetization showed that TB shifted from 17 

K to 57 K as the amount of Fe ions increased, and below TB, ferromagnetic behaviors 

were observed. Coercive force (HC) increased from 0.8 kOe to 1.5 kOe as the 

amount of Fe ions increased. This phenomenon can be explained by characteristics of 

extremely small particles in this system. 

RN03 

Uniaxial strain effects on spinel ferrite nanoparticles containing Nd 

and B elements 

Masaki Mito 1 , Seiya Saisho 2 , Hiroyuki Deguchi 1 , Takashi Iwamoto 3 and Atsushi 

Takahara 4 

1 

Department of Basic Science, Kyushu Institute of Technology, Japan 

2 

Department of Applied Science for Integrated System Engineering, Kyushu Institute 

of Technology, Japan 

3 

Institute for Sustainability Research and Education, Hosei University, Japan 

4 

Institute for Materials Chemistry and Engineering, Kyushu University, Japan 

We studied the uniaxial strain effects on spinel ferrite nanoparticles that containined Nd 

and B elements (Nd : Fe : B = 10.4 : 83.5 : 6.1) and had the particle size of 5.1 nm. In 

diffused magnetic nanoparticles, the magnetic easy-axis is distributed randomly, and it 

is impossible to add the strain along a specific structural axis of each particle. However, 

in order to control the magnetic property of the magnetic nanoparticles, the application 

of the uniaxial strain for the particles with the uniform easy-axis vector is preferable 

to that of hydrostatic pressure for randaomly diffused particles. In this study, magnetic 

easy-axis of each particle was arranged by solidifying an epoxy resin containing the 

particle at the dc magnetic field of 1 T, resulting in creating an assembly of uniformly 

oriented nanoparticles. Afterward, the strain was applied along both the magnetic 

easy-axis and hard-axis. In both situations, the magnetic blocking temperature had 

the maxmimum at the strain of about 3-5 kbar. The difference between two strainexpeirments 

appeared at pressure of above 10 kbar. 

RN04 

The magnetic proximity effect in Fe 3O 4 core/γ-Mn 2O 3 shell 

nanoparticles 

S. M. Yusuf* and P. K. Manna 



The phenomenon of ‘proximity effect’ is very popular in the context of superconductor/ 

non-superconductor heterostructures. In the present study, we report the magnetic 

proximity effect in a core-shell nanoparticle system by employing dc magnetization 

and neutron diffraction techniques. In a heterostructure, the substrate, used for its 

deposition, often modifies the magnetic properties of the deposited layers. However, a 

core-shell nanoparticle system, being substrate-free, rules out any such possibility. We 

have observed magnetic proximity effect in a Fe 3O 4 core/γ-Mn2O3 shell nanoparticle 

system, in terms of an enhancement of the Curie temperature (Tc) of the γ-Mn 2O 3 shell 

(~66K) compared to its bulk value (~40K), and the presence of magnetic ordering in 

its so-called paramagnetic region (i.e. above 66K). The origin of these two features has 

been ascribed to the proximity of the γ-Mn 2O 3 shell with a high-Tc Fe 3O 4 core (~858K 

in bulk form) and an interface exchange coupling between core and shell. Interestingly, 

no exchange bias effect is found due to a weak interface exchange coupling between 

core and shell. The present study brings out the importance of the relative strength of 

interface coupling in governing the simultaneous occurrence of the magnetic proximity 

effect and the exchange bias phenomenon in a single system. 

RN05 

RN06 

RN07 


Covalent immobilization of biotin on superparamagnetic nanoparticles 

Long Giang Bach 1 , Md. Rafiqul Islam 2 and Kwon Taek Lim 2 * 

1 

Department of Imaging System Engineering, Pukyong National University, 608-737, 

Busan, Korea, Korea 

2 

Department of Imaging System Engineering, Pukyong National University, Busan, 

Korea, Korea 

Among the magnetic materials, the nano-scale structured magnetite, Fe3O4 is 

widely applicable magnetic nanparticles (MNPs). MNPs offer attractive possibilities 

in biomedicine, biosensor, and separation processes because of their unique 

properties of superparamagnetism, biocompatibility and low toxicity. The ease of 

synthesis and subsequent surface functionalization of MNPs with a desired material 

improve biocompatibility which creates an avenue of delivering multimodal and 

multifunctional MNPs. In this study, a simple protocol of covalent immobilization 

of biotin on the surface of MNPs for improving biocompatibility and cell viability of 

the original MNPs has been demonstrated. MNPs were prepared using a solution of 

ferrous and ferric ions. The anchoring of 3-aminopropyltrimethoxysilane with MNPs 

resulted due to the formation of Fe-O-Si covalent linkage which is quite strong and 

having free amino group. The hydroxyl groups of the biotin were activated by N,N'disuccinimidyl 

carbonate followed by conjugation with MNPs-NH2 to afford Biotin- 

MNPs. The conjugation of biotin to MNPs was confirmed by FT-IR, XPS and EDX. 

The Biotin-MNPs showed superparamagnetic character as investigated by SQUID. 

Fabrication of (Mn-Al)/Pd or Ni with Core-Satellite Structured 

Magnetic Particles 

Youn-kyoung Baek*, Jung-goo Lee and Chul-jin Choi 

Powder & Ceramic Division, Korea Institute of Materials Science, Korea 

WITHDRAWN 

The effect of hydrostatic pressure on the Morin transition in hematite 

nanoparticles 

Luana Caron1*, Davide Peddis2, Lorenza Suber3, Dino Fiorani3 and Per Nordblad4 

1 Fundamental Aspects of Materials and Energy, Faculty of Applied Sciences, TU Delft Mekelweg 

15, 2629JB Delft, Netherlands 

2 Dipartimento di Scienze Chimiche, Universita degli Studi di Cagliari,, Cittadella Universitaria di 

Monserrato 09042 Cagliari, Italy 

3 Istituto di Struttura della Materia, Area della Ricerca di Roma, CNR Via Salaria km 29500, CP 

10-00016 Monterotondo Stazione, Rome, Italy 

4 Department of Engineering Sciences, Uppsala University Box 534, 751 21 Uppsala, Sweden 

Recently, hematite particles have been the subject of intensive studies in areas as diverse as magnetic storage 

media, photo electrodes and catalysis[1,2]. Hematite is an antiferromagnetic system that displays a spin 

reorientation from uniaxial to canted antiferromagnetism at the Morin temperature[3]. Particle shape, size and 

microstructural defects have strong influence on the Morin temperature and thus can be used to tune the system’s 

magnetic response. It is known that the Morin transition temperature decreases along with particle size as a result 

of the increasing lattice spacing[4], whereas an increase of the Morin temperature under hydrostatic pressure is 

observed in the bulk material[5]. In a novel approach, we report on the effect of hydrostatic pressures on hematite 

rhombohedral nanoparticles of narrow size distribution = 93 ± 2 nm[6]. Pressure was found to increase 

the Morin temperature at a rate of ~ 5 K/kbar and considerably decrease thermal hysteresis. These results strongly 

contrast with the effects of pressure on the bulk material where a milder influence of pressure on both the Morin 

temperature and thermal hysteresis is observed. 

[1] Zhihong Jing, Shihua Wu, Mater. Lett. 58, 3637 (2004) [2] K. Sivula, F. Le Formal and M. Gratzel, ChemSusChem 4, 417 (2011) [3] F. J. Morin, Phys. Rev. 78, 819 (1950) [4] D. 

Schroeer and R. C. Nininger, Phys. Rev. Lett. 19, 632 (1967) [5] T. G. Worlton and D. L. Decker, Phys. Rev. 171, 596 (1968) [6] L. Suber et al., Phys. Chem. Chem. Phys. 12, 6984 (2010) 


Poster Thursday



RN08 

Ultra-thin MgO coating of superparamagnetic magnetite nanoparticles 

by combined co-precipitation and sol-gel synthesis 

Laura De Matteis 1 , Laura Custardoy 1 , Rodrigo Fernandez-pacheco 2 , Cesar Magen 3 , 

Jesus M De La Fuente 4 , M R Ibarra 5 and Clara Marquina 6 * 

1 Instituto de Nanociencia de Aragon- INA, Universidad de Zaragoza, Spain 

2 Laboratorio de Microscopias Avanzadas (LMA) - Instituto de Nanociencia de Aragon (INA, 

Universidad de Zaragoza, Spain 

3 Laboratorio de Microscopias Avanzadas (LMA) - Instituto de Nanociencia de Aragon (INA, 

Departamento de Fisica de la Materia Condensada Universidad de Zaragoza Fundacion ARAID, Spain 

4 Instituto de Nanociencia de Aragon- INA, Universidad de Zaragoza Fundacion ARAID, Spain 

5 Instituto de Nanociencia de Aragon (INA)- Laboratorio de Microscopias Avanzadas (LMA), 

Departamento de Fisica de la Materia Condensada Universidad de Zaragoza, Spain 

6 Instituto de Ciencia de Materiales de Aragon-ICMA, Departamento de Fisica de la Materia 

Condensada CSIC-Universidad de Zaragoza, Spain 

Superparamagnetic magnetite nanoparticles coated with an ultra-thin (~1 nm) magnesium oxide (MgO) 

layer have been synthesized by combining co-precipitation and sol-gel methods. A thorough chemical and 

structural characterization has been carried out by means of HRTEM, XRD, EDS, DLS and TGA. Aberration 

corrected HRTEM experiments with sub-angstrom spatial resolution have allowed us to distinguish the ultrathin 

MgO shell that grows epitaxially on the magnetic cores. The capability of the MgO shell to protect the 

magnetic nuclei from oxidation up to 600ºC has been demonstrated. The magnetic properties of the material 

have been studied before and after the coating procedure. The superparamagnetism of the magnetite nuclei 

at room temperature is preserved even after calcination. The possibility of obtaining particles of controlled 

size coated with an isolating layer of nanometric thickness and high thermal stability makes the combination 

of the two synthesis methods used in this work a starting procedure to obtain nanometric powders suitable 

for technological applications, such as high-frequency electronics. These particles, after the appropriated 

functionalization, are also potential candidates to be used in biomedical applications 

RN09 

Synthesis and characterization of ultra-small magnetic FeNi/G and 

NiCo/G nanoparticles 

Mariana Castrillon 1 , Alvaro Mayoral 2 , Cesar Magen 3 , Johan G. Meier 1 , Clara 

Marquina 4 *, Silvia Irusta 5 and Jesus Santamaria 5 

1 

Technological Institute of Aragon (ITA), Zaragoza, Spain 

2 

Instituto de Nanociencia de Aragon (INA)- Laboratorio de Microscopias Avanzadas (LMA), 

Universidad de Zaragoza, Spain 

3 

Instituto de Nanociencia de Aragon (INA)- Laboratorio de Microscopias Avanzadas (LMA), 

Departamento de Fisica de la Materia Condensada Universidad de Zaragoza, Spain 

4 

Instituto de Ciencia de Materiales de Aragon-ICMA, CSIC-U. Zaragoza, Spain 

5 

Instituto de Nanociencia de Aragon- INA, Networking Research Center on Bioengineering, 

Biomaterials and Nanomedicine, CIBER-BBN U. Zaragoza, Spain 

Ultra-small magnetic nanoparticles consisting of NiCo and FeNi alloys coated by graphitic shells (NiCo/G 

and FeNi/G) have been synthesized by a procedure similar to that described by Seo et al. [1]. The cores, which 

retained the face-centered cubic (fcc) symmetry of the original bulk metals, together with the graphitic coating 

have been characterized by means of aberration corrected scanning transmission electron microscopy (STEM). 

The particles have mean sizes of 2.6 nm and 6.2 nm for NiCo/G and FeNi/G, respectively. The samples contain 

a large fraction of superparamagnetic nanoparticles at room temperature. The thermal stability of the particles 

is enhanced by the graphite shell, and the graphite coated FeNi and NiCo are stable under oxygen atmosphere 

up to 170 C. Non-coated bimetallic FeNi and NiCo have also been prepared. Their chemical characterization 

revealed the massive oxidation of the bimetallic nanoparticles in absence of the graphite coating (oxygen content 

higher that 60 at. %). This fact confirms the effectiveness of the graphite shell in preventing the magnetic cores 

from oxidation and therefore preserving their magnetic properties even at high temepratures. 

1.- Seo W. S. et al., Nature Mater. 5 (2006) 971-6 

RN10 

Magnetization measurements and blocking temperature distribution 

in magnetic nanoparticle systems 

Taehoon Lee 1 , Seunghyun Kim 1 , Sungwon Yoon 2 , Byoung Jin Suh 2 *, Zeehoon Jang 1 

and Kyunghyun Kim 3 

1 Department of Physics, Kookmin University, Korea 


3 Biotechnology & Bioinformatics, Korea University, Korea 

We present magnetization measurements on a variety of magnetic nanoparticle 

ensembles. The samples are; (1) Artificailly synthesized Helicobacter Pylori ferritin 

reconstituted with three different Fe ions/ferritin ratio, 160, 2000, and 4000. (2) 

Commercial horse spleen ferritin (3) CoPt nanoparticles with average particle size of 

2 nm. Temperature dependence of magnetization has been measured using a SQUID 

magnetometer. Measurement sequence has been modified from a typical field-cool 

sequence and the measurements have been performed with field “stop-resume” steps 

at the regular temperature interval. Using a phenomenological model, we could extract 

the moment weighted blocking temperature distributions in the samples from the 

experimental data. The model is based on the assumptions that; 1) the particles in the 

ensembles can be uniquely categorized in terms of the blocking temperature. 2) the 

particles with the same blocking temperature will have the same field and temperature 

dependence of the magnetization. 3) the particles are non-interacting with each other. 

With the obtained distributions, the numerical simulations are performed to reproduce 

the field-cool magnetization data and zero-field-cool magnetization data. 


RN11 

Structural and magnetic anomalies in CoAl2O4 nanocrystals 

Koichi Sato 1 , Takashi Naka 1 , Takayuki Nakane 1 , Minori Taguchi 1 , Dinesh Rangappa 2 , 

Satoshi Ohara 3 and Tadafumi Adschiri 4 


2 <strong>International</strong> Advanced Research Centre for Powder Metallurgy & New Materials, India 

3 Joining and Welding Research Institute, Osaka University, Japan 

4 WPI, Advanced Institute for Materials Research, Tohoku University, Japan 

In this study, we investigated magnetic properties of spinel CoAl 2O 4 nanocrystals (NCs) synthesized by a 

supercritical hydrothermal synthesis. We confirmed that all the samples are composed of the single phase 

CoAl 2O 4 by the X-ray diffraction measurements. Crystalline sizes are controlled to be 4 ? 8 nm. We also 

found that the inversion parameters of the samples, describing the cation distribution are more than 0.3 [1,2], 

being much higher than bulk specimens previously reported. We conducted magnetization and, dc- and acsusceptibility 

measurements. All the samples show paramagnetic behavior above 70 K. The effective Bohr 

magnetons and the Weiss temperatures are 2.6 - 2.8 μB and -40 - -50 K. The effective Bohr magnetons are 

smaller than 4.4 - 4.6 μB reported on specimens with the low inversion parameters [3,4]. The susceptibilities 

deviate from Curie-Weiss law below 40 - 50 K. From the results of the magnetization measurements, it was 

found that spontaneous magnetization, 0.1 μB/Co, emerges below 40 K in the samples with the size of 4 

nm. The reduced Bohr magnetons and the emergence of the spontaneous magnetization indicate that in our 

NC samples, a certain magnetic phase, being different from those of bulk specimens, appears below 40 K. 

[1] N. Tristan, J. Hemberger, A. Krimmel, H-A. Krug von Nidda, V. Tsurkan, and A. Loid, Phys. Rev. B 72, 174404 (2005) [2] T. 

Suzuki, H. Nagai, M. Nohara, and H. Takagi, J. Phys. Condensed matter 19, 145265 (2007). [3] H. St. C. O'neill, Eur. J. Mineral. 6, 

603 (1994). [4] A. Nakatsuka, Y. Ikeda, Y. Yamasaki, N. Nakayama, and T. Mizota, Solid State Commun. 128, 85 (2003). 

RN12 

Preparation of chains of single-domain Ni nanoparticles with collinear 

direction of magnetization 

S A Nepijko 1 *, D Kutnyakhov 1 , I E Protsenko 2 , H J Elmers 1 , R Wiesendanger 3 and G 

Schoenhense 1 

1 Institute of Physics, University of Mainz, Germany 

2 Department of Applied Physics, Sumy State University, Ukraine 

3 Institute of Applied Physics, University of Hamburg, Germany 

Networks of ferromagnetic nanoparticles have been proposed to form quantum cellular automata [1]. We 

present a fabrication method based on self-organized growth on stepped surfaces for fairly regular nanoparticles 

arranged in a one-dimensional chain, that are suitable for this application. We studied Ni nanoparticles with 

sizes in the range 80-130 nm on a highly-ordered pyrolytic graphite (HOPG) substrate and succeeded to 

prepare one-dimensional chains of these single-domain particles characterized by the same direction of their 

magnetization. The nanoparticles were found to decorate atomic cleavage steps on the basal surface and their 

distances are small enough to give rise to strong dipolar coupling. The necessary and sufficient conditions are: 

(i) 3D growth mechanism along with non-wetting behaviour, (ii) the dielectric substrate has atomic cleavage 

steps, (iii) the size of the ferromagnetic particles is smaller than the characteristic domain size but still above 

the transition into the superparamagnetic state and, finally, (iv) the distances between the particles are small 

enough for dipolar coupling. The study was carried out using atomic-force (AFM) and magnetic-force (MFM) 

microscopy. The approach of ordering ferromagnetic nanoparticles into one-dimensional chains is of particular 

interest because chains are a basic block for storage and transport of information. 

[1] R.P. Cowburn, M.E. Welland, Science 287 (2000) 1466 

RN13 

Influence of the morphology on the magnetic properties of 

dodecanethiol-capped Au anoparticles 

Daniel Ortega 1 , Eider Goikolea 2 , Jose Javier Garitaonandia 2 , Maite Insausti 2 , Hyodo 

Zhang 3 , Kiyonori Suzuki 3 and Fernando Plazaola 2 

1 Department od Physics and Astronomy, University College London Gower Street 

WCIE 6BT London, United Kingdom 

2 Zientzia eta Teknologia Fakultatea Euskal Herriko Unibertsitatea, Spain 

3 Department of Materials Engineering, Monash University, Australia 

It has been proved that Au nanoparticles (NP) coated with certain molecules can present different magnetic 

characters, ranging from superparamagnetism to permanent magnetism at room temperature (RT) [1-3]. We have 

prepared ferromagnetic dodecanethiol-capped Au NPs with a high magnetic signal of 1.7 emu/gr and coercive 

field of 85 Oe at RT. An analysis by high resolution electron microscopy reveals that the NPs are composed by ~ 

200 atoms forming multi-twinned structured nanocrystals of ~ 2 nm with icosahedral or decahedral morphologies 

where well ordered fcc twinned entities are joined forming an only nanocrystal with a spatial 5-fold symmetry. 

The external morphology is conditioned by the final stabilization of the NP and, with a surface to bulk atoms ratio 

up to ~ 75% and a magnetism located exclusively in the surface atoms, the morphology plays a crucial role in the 

definition of the magnetic character of the NP. In a comparative view with the multidomain structures presented 

in bulk materials, we argue that borders among the twinned nanosized entities would act as pinning centers, 

hindering the alignment of the magnetic moments between entities and promoting the coercive field. 

[1] Y. Yamamoto, T. Miura, M. Suzuki, N. Kawamura, H. Miyagawa, T. Nakamura, K. Kobayashi, T. Teranishi, 

and H. Hori, Phys. Rev. Lett. 93 116801 (2004). [2] P. Crespo, R. Litran, T. C. Rojas, M. Multigner, J. M. de la 

Fuente, J. C. Sanchez-Lopez, M. A. Garcia, A. Hernando, S. Penedes, and A. Fernandez, Phys. Rev. Lett. 93 

087204 (2004). [3] J. S. Garitaonandia, M. Insausti, E. Goikolea, M. Suzuki, J. D. Cashion, N. Kawamura, H. 

Ohsawa, I. Gil de Muro, K. Suzuki, F. Plazaola, and T. Rojo, Nanoletters 8 661 (2008).

RN14 

Structure effects on the magnetic behavior in Fe oxide based 

nanoparticles 

Amilcar Labarta*, Carlos Moya, Nicolas Perez, Arantxa Fraile, Oscar Iglesias and 

Xavier Batlle 

Fundamental Physics, University of Barcelona, Spain 

A key question in magnetic nanoparticles (NP) is how the nanostructure modifies their magnetic and electronic 

properties. As the particle size is reduced, deviations from bulk behaviour have been widely reported and 

attributed to both the appearance of a magnetically disordered surface layer and finite-size effects, thus giving 

rise to a decrease in the particle magnetization, an exchange field acting on the core and an increase in the 

anisotropy. In order to elucidate those phenomena we have carried out STEM, XAS, XMCD and magnetization 

measurements in Fe oxide based NP models, aiming at the real-space characterization at the sub-nanometer 

scale of a single NP to characterize the particle structure, surface magnetization, and the dependence of the 

latter on the strength of the surface bond to a bio-molecule coating. We also aim at the quantification of the 

orbital and spin contributions to the NP magnetic moment. The key role of the crystal quality is thus suggested, 

because particlelike behaviour above about 5 nm in size is observed only when NP are structurally defective. 

These conclusions are supported by Monte Carlo simulations. It is also shown that thermal decomposition is a 

chemical route capable of producing high-crystal quality NP with bulklike properties. 

1. N. Perez, F. Bartolome, L.M. Garcia, J. Bartolome, M.P. Morales, C.J. Serna, A. Labarta and X. Batlle, Applied Physiscs Letters 

94, 093108 (2009). 2. P. Guardia, N. Perez, A. Labarta and X. Batlle, Langmuir , 26, 5843-5847 (2010). 3. X. Batlle, N. Perez, 

O. Iglesias, A. Labarta, F. Bartolome, L.M. Garcia, J. Bartolome, A.G. Roca, M.P. Morales, and C.J. Serna, Journal of Applied 

Physics 109, 07B524 (2011). 4. Work in collaboration with: F. Bartolome, L.M. Garcia, J. Bartolome (ICMA-CSIC, Spain); M.P. 

Morales and C.J. Serna (ICMM-CSIC, Spain); M. Varela, J. Salafranca and J. Gazquez (OAK-Ridge National Laboratory, USA). 

RN15 

Magnetic properties of surface-functionalized nano-particles 

Ann Kathrin Michel 1 , Mathias Kraken 1 , Jochen Litterst 1 *, Yannick Guari 2 , Joulia 

Larionova 2 , Lenaic Lartigue 2 , Jerome Long 2 and Alessandro Lascialfari 3 

1 IPKM, TU Braunschweig, Germany 

2 Institut Charles Gerhardt, Universite Montpellier II, France 

3 CNRNANO, Univ. Milano, Italy 

RN16 

WITHDRAWN 

Study of aqueous dispersions of magnetic nanoparticles by magnetic 

and rheological measurements 

Shalini M 1 , Mahesh Samant 2 , Radha S 3 * and D. C. Kothari 3 

1 Department of Physics and UM-DAE CBS, University of Mumbai, India 

2 National Center for Nanosciences and Nanotechnology, University of Mumbai, India 


The observed magnetic tunability of light transmission through a ferrofluid [1] can be effectively understood 

in terms of the inter-particle interaction that can be estimated from the magnetic and rheological properties of 

these fluids. The present study reports complementary magnetic and rheological measurements of synthesized 

aqueous dispersions of ferrite nanoparticles, using a commercial ferrofluid as a standard. The aqueous 

dispersions of the ferrite nanoparticles were synthesized by co-precipitation using suitable precursors and 

surfactants. The dispersions were stable for reasonably long durations and the particle size was estimated 

to be 10-28 nm from XRD measurements. The room temperature magnetization measured in a SQUID 

magnetometer up to fields of 1 Tesla showed superparamagnetic behaviour of the powder and the dispersion 

with the background signal of the liquid varying from a diamagnetic to a paramagnetic behaviour. The room 

temperature rheological behaviour in zero magnetic field of both the standard and synthesized dispersion 

was investigated by measuring the viscosity as a function of shear rate from 1-1000s-1. The viscosity of 

the dispersion increased with increasing shear rate reaching a constant value at higher shear rates; while the 

standard sample showed almost no change in viscosity with shear rate conforming to a Newtonian behaviour. 

[1] M. Shalini, D. Sharma, A. A. Deshpande, D. Mathur, Hema Ramachandran and N. Kumar, Eur. Phys. Jour. D 66 (2012) 30. 

RN17 

RN18 

RN19 


Magnetodielectric effect of Fe 2O 3 nanoparticles embedded in SiO 2 

glass matrix 

Hung-cheng Wu, Sudip Mukherjee and Hung-duen Yang* 

Department of Physics, National Sun Yat-sen University, Taiwan 

Magnetic iron-oxide (doping 0.5 mole %) nanoparticles (NPs) have been synthesized 

in silica glass matrix, prepared by the sol-gel method with different annealing 

temperatures. XRD, TEM and XANES show the presence of NPs of Fe 2O 3 and Fe 3O 4 

crystalline phase (< 5 nm). An interesting colossal enhancement of dielectric constant 

with diffuse phase transition is observed around room temperature due to the thermally 

activated oxygen vacancies. The magnetodielectric effect observed in the glass 

composites is considered to be associated with magnetoresistance changes, depending 

on NPs size. 

Tuning the concentration of magnetic Co nanoparticles in In 2O 3 with 

oxygen pressure and concentration of tin 

Marzook S. Alshammari 1 *, Mohammed S. Alqahtani 1 , Qi Feng 1 , S. Alfahad 2 , M. Alotibi 2 , A. 

Alyamani 2 , A. M. H. R. Hakimi 3 , S. M. Heald 4 , H. J. Blythe 1 , A. M. Fox 1 and G. A. Gehring 1 

1 Department of physics and astronomy, University of Sheffield, United Kingdom 

2 Nanotechnology center, King Abdulaziz City for Science and Technology, Saudi Arabia 

3 Department of Materials Science and Metallurgy, University of Cambridge, United Kingdom 

4 Advanced Photon Source, Argonne National Laboratory, USA 

This study shows the power of combining magnetic measurements with magnetic circular dichroism (MCD) 

to detect the contribution to the magnetism from metallic Co nanoparticles, and the result that the formation 

of nanoparticles is suppressed by the inclusion of tin. Thin films of (In 1-0.95Co 0.05) 2O 3 were deposited using 

pulsed laser deposition (PLD) on sapphire substrates. The magnetism and the amount of cobalt in nanoparticles 

increased with the oxygen deficiency in the PLD chamber and also after annealing in vacuum as expected and 

as confirmed using Extended X-ray Absorption Fine Structure. The MCD spectra show two features that are 

well fitted by a combination of the spectrum from the nanoparticles in the In 2O 3 matrix, as calculated using 

Maxwell-Garnett theory, and a contribution from polarized carriers [1]. The changes in the magnetization and 

the MCD are used to get a quantitative estimate of the contribution of the nanoparticles magnetization to the 

total magnetization in each sample. Adding 5% of Sn made little difference to the saturation magnetization 

but the signal due to Co nanoparticles was completely suppressed and that from polarized carriers enhanced 

strongly. This indicates that, the magnetization of the carriers in Sn and Co co doped In 2O 3 is particularly high. 

Hakimi, et al, Physical Review B 84, 085201 (2011). 

Synthesis, structural, and magnetic properties of strontrium 

hexaferrite nanoparticles with La, Sm doping and core/shell structure 

by the sol-gel hydrothermal process 

Hue Thi Minh Dang 1 , Dien Xuan Luong 1 , Hoang Duc Tran 1 , Huong Manh Phan 2 and Chinh Dang Huynh 1 * 

1 Department of Inorganic Chemistry, Hanoi University of Science and Technology, Viet Nam 

2 Department of Physics, University of South Florida, USA 

SrFe 12O 19 nanoparticles have been prepared by the sol-gel hydrothermal method. 

These SrFe 12O 19 nanoparticles have been doped with La, Sm and coated with NiFe 2O 4, 

CoFe 2O 4 nanoparticles by the sol-gel and the self-assembly method, respectively. 

Properties of the nanoparticle samples were charaterized by powder X-ray diffraction 

with the Rietveld refinement, transmission electron microscope, scanning electron 

microscopy with energy dispersive spectrometer, and vibrating sample magnetometry. 

SEM micrograhs of the samples showed the spherical shape of NiFe 2O 4, CoFe 2O 4 

nanoparticles located above on the surface of SrFe 12O 19 hexagonal platelet shape. 

TEM micrographs showed the particle size of core and shell. With the core/shell 

nanoparticles, the saturation magnetization was decreased but coercivity was increased 

with SrFe 12O 19/CoFe 2O 4 sample. 

[1.] Alex Goldman, Modern Ferrite Technology, Springer; 2nd edition (2005). [2.] Smit J., Wijn H.P.J, Ferrits-Physical 

properties of ferritmagnetic oxides in relation to their technical application, Philip Technical Library, Eindhoven, (1959). [3.] L.A. 

Garcia-Cerda, O.S. Rodriguez-Fernandez, P.J. Resendiz-Hernandez, Journal of Alloys and Compounds 369 (2004) 182-184. [4.] 

Malick Jean, Virginie Nachbaur, Julien Bran, Jean-Marie Le Breton, Journal of Alloys and Compounds 496 (2010) 306-312. 

[5.] Xiaofeng Yang, Qiaoling Li, Jingxian Zhao, Baodong Li, Yongfei Wang, Journal of Alloys and Compounds 475 (2009) 312- 

315. [6.] T. T.V. Nga , N.P. Duong, T.D. Hien, Journal of Alloys and Compounds 475 (2009) 55-59. 


Poster Thursday



RN20 

A facial fabrication of the superparamagnetic Fe 3O 4@TiO 2 

microspheres and its photocatalytic application 

Kyong-hoon Choi 1 , Eun-mee Kim 2 , Seung-lim Oh 3 , Do-yeon Kim 4 and Jin-seung Jung 4 * 

1 Material R&D Division, H & Global Co. Ltd., Korea 

2 Gangneung Center, korea Basic Science Institute, Korea 

3 Material R&D Division, H & Global Co. Ltd., Korea 

4 Department of Chemistry, Gangneung-Wonju National University, Korea 

Over the past few decades, semiconductor photocatalysts have attracted much attention because of their 

applications in new energy fields where they represent a promising strategy for splitting water to provide 

clean hydrogen energy, and their use in the photocatalytic degradation of polluted atmosphere and wastewater 

in environmental remediation[1,2]. Among the reported photocatalysts, titanium dioxide (TiO 2 ) is one of 

the most studied semiconductors for photocatalytic reactions because of its high activity, chemical stability, 

robustness against photocorrosion, low toxicity and availability at low cost, especially for the detoxification of 

water and air [3,4]. In this study, we have successfully synthesized of multifunctional core/shell (Fe 3O 4/TiO 2) 

submicron particles with controlled shell thickness. In the first step, superparamagnetic Fe 3O 4 submicron 

particles were fabricated by one-step hydrothermal method. In the second step, the surface of Fe 3O 4 submicron 

particles was coated with TiO 2 by atomic layer deposition (ALD) method. Through this method, the thickness 

of shell was accurately tunable. The recyclable Fe 3O 4@TiO 2 particles exhibit excellent catalytic properties for 

the oxidation reaction of 2,4,6-trichlorophenol (2,4,6-TCP) in aqueous solution. 

[1]. A. Fujishima, K. Honda, Nature, 238, 37 (1972) [2]. X. C. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, G. M. 

Garlsson, K. Domen, M. Antonietti, Nat. Mater., 8, 76 (2009) [3]. T. L. Thompson, J. T. Yates Jr., Chem. Rev. 106, 4428 (2006) 

[4].A. C. Rodrigues, M. Boroski, N. S. Shimada, J. C. Garcia, J. Nozaki, N. Hioka, J. Photochem. Photobiol. A 194, 1 (2008) 

RN21 

Synthesis of high moment magnetite (Fe 3O 4) nanoparticles by simple 

modified polyol method 

Mohamed Abbas Ali Ahmed and Cheolgi Kim* 

Material Science and Engineering, Chungnam National University, Korea 

(Synthesis of high moment magnetite (Fe 3O 4) nanoparticles by simple modified 

polyol method) Mohamed Abbas and CheolGi Kim Center for NanoBioEngineering 

and Spintronics, Department of Materials Science and Engineering, Chungnam 

National University, Daejeon 305-764, Korea Abstract Single phase magnetite with 

high saturation magnetization and 50 nm as a medium range particles size has been 

synthesized by in expensive and surfactant-free simple modified polyol method using 

FeCl 2.4H 2O as a precursor of iron and Poly Ethylene Glycol (PEG) as a solvent and 

reducing agent simultaneously. X-ray diffraction (XRD) and EDS analysis indicated 

that, formation of purely magnetite (Fe 3O 4) without presence of any other phase. 

Transmission electron microscopy (TEM) also show that the synthesized nanoparticles 

are almost sphere in shape. The magnetic properties of the synthesized magnetite 

nanoparticles were measured by means Physical Property Measurement System 

(PPMS-VSM) at different temperature and shows that the as-synthesized NPs were 

ferromagnetic with high moment 91.7 emu/g at 5 K. Corresponding author. Tel:- 

+82428216236 E-mail address: cgkim@cnu.ac.kr (Prof/ CheolGi Kim) 

RN22 

Study of Structural, morphological and optical properties of SrFe 12-x 

Co x O 19 (x= 0, 0.1, 0.2) hexaferrite nanoparticles 

Morteza Zargar Shoushtari*, Ebrahim Mousavi Ghahfarokhi and Fereshte Ranjbar 

Physics, Shahid Chamran University of Ahvaz, Iran 

A series of M-type strontium hexaferrite samples having nominal composition SrFe 12-x 

Co x O 19 (x = 0.0, 0.1 and 0.2) with different morphologies have been synthesized via 

sol gel method. For synthesis of samples, first a precursor gel was prepared using the 

sol-gel method. The mixture of KCl and dry-gel was calcined at 1000 ˚C for 2 h to 

obtain the needle-like nano- SrFe 12-x Co x O 19. The rod-like and bubble nano- SrFe 12-x 

Co x O 19 was prepared by calcining the mixture of KBr and dry-gel or KI and dry-gel, 

respectively, and spherical nano- SrFe 12-x Co x O 19 was prepared only by calcined drygel. 

The structure and morphology of samples were systematically characterized by X- 

ray diffraction (XRD), scanning electron microscopy (SEM). The optical properties 

of samples were investigated by UV-Vis. The result of XRD of samples showed that 

the M-type hexagonal structure can be maintained for all the samples without the 

segregation of secondary phases. The FT- IR frequency bands in the range 560 - 580 

cm -1 and 430 - 470 cm -1 in the all of samples corresponds to the formation of tetrahedral 

and octahedral clusters of metal oxides in ferrites, respectively. 


RN23 

Light induced ferromagnetism of nanocrystalline CuCr 2Se 4 particles 

Dongsoo Kim*, Kookchae Chung and Choljin Choi 

Korea Institute of Materials Science, Korea 

A novel method to synthesize ternary chalcogenide nanoparticles was developed with 

microwave-assisted polyol reaction in this study. Copper chloride, chromium acetate and 

metallic selenium were used as precursors with stoichiometric ratios in poly ethylene glycol. The 

system was purged with argon and then the mixed reactants were irradiated for 60 minutes with 

60% of the instrument power. Products were collected, centrifuged, washed with ethyl alcohol 

in order to remove poly ethylene glycol and dried overnight under inert atmosphere. Magnetic 

moment of CuCr 2Se 4 nanoparticles was measured from 300 K to 750 K with external magnetic 

field of 500 Oe in argon atmosphere and Curie temperature was calculated as 445 K. From 

the hysteresis loop, magnetic property was ferromagnetic and its saturation magnetization and 

coercive force were measured to 15 emu/g and 80 Gauss respectively. Nanocrystalline CuCr 2Se 4 

particles were dispersed in the matrix of light transparent resin so as to investigate light induced 

effect on the magnetic properties. Er-laser with the wavelength of 1.5 µm was employed as light 

source. Light illumination in an external magnetic field increased the magnetization and this 

increment of magnetization (δJ) to initial magnetization (J) showed a maximum. 

1. Mingos D.M.P. The application of microwaves in chemistry // Res. Chem. Intermed., 1994, V. 20, P. 85-91. 2. 

Baran M., Szymczak R., Szymczak H., Tsurkan V. Spin glass like behavior of magnetization in anion substituted 

CuCr2Se4 magnetic semiconductor // J. Magn. Magn. Mater., 1995, V. 140-144, P. 2043-2047. 3. Boukari H., 

Kossacki P., Bertolini M., Ferrand D., Cibert J., Tatarenko S., Wasiela A., Gaj J.A., Dietl T. Light and electric 

field control of ferromagnetism in magnetic quantum structures // Phys. Rev. Lett., 2002, V. 88, N. 20, P. 204-207. 

RN24 

Magnetite nanoparticles in hybrid aerogel and PEG encapsulated of 

magnetite nanoparticles for the hyperthermia application 

Eunhee Lee and Chang-yeoul Kim 

KICET, Korea 

Magnetite nanoparticles have received intensive attractions because of their 

applications as magnetic carriers in drug targeting and hyperthermia in tumor 

treatment. However, magnetite nanoparticles with 10 nm in diameter easily aggregate 

themselves to form large secondary particles. To disperse magnetite nanoparticles, 

this research paper suggests the infiltration of magnetite nanoparticles into hybrid 

silica aerogels. The PEG encapsulate of magnetite is to disperse magnetite up in PBS 

solution. The well-dispersion of magnetite is necessary for target the tumor cells 

and hyperthermia treatment. Methyltriethoxysilicate (MTEOS) based hybrid silica 

aerogels were synthesized by a supercritical drying method. To incorporate magnetite 

nanoparticles into the hybrid silica aerogels, we immersed it into magnetite precursor 

solution. The surfaces of magnetite nanoparticles were modified by PEG(polyethylene 

glycol). The infiltration and PEG coating of magnetite nanoparticles were identified 

by XRD, FT-IR and TEM. Vibrating Sample Magnetometer analysis showed that 

the composite of the magnetite and hybrid silica aerogel is superparamagnetic. The 

temperature behaviors of the magnetite composite and the surface coated magnetite 

nanoparticles were discussed in the context of the change of magnetite particles with 

PBS for Hyperthermia application. 

RO01 

Effect of the Cu content on the microstructural and magnetic 

properties of Nd-Fe-B sintered magnets 

Tae-hoon Kim 1 , Seong-rae Lee 1 *, Seok Namkung 2 and Tae-suk Jang 2 


2 Sunmoon University, Korea 

The Cu addition in the Nd-Fe-B sintered magnet improves the coercivity after the post-sintering 

annealing (PSA) because the continuous Nd-rich grain boundary phase (GBP) and the metastable 

C-Nd 2O 3 phase were formed [1-3]. However, the magnetic properties of the commercial magnet 

were deteriorated when the Cu content of the magnet is higher than 0.15 at.% (optimized Cu 

content). In this study, we investigated the Cu content effects on the microstructural and magnetic 

properties of sintered 12Nd-2.7Dy-(76.45-x)Fe-xCu-6B-2.65M (at.%, x=0.2, 0.3, 0.4, 0.5) magnets. 

The coercivity was decreased (28.7→26.1 kOe) with increasing the Cu content, but the remanence 

was unchanged. Two kinds of Cu enriched Nd-rich triple junction phases (Cu-rich TJP), such as 

5~10 at.% Cu containing Nd-rich TJP (Culow-rich) and 35~45 at.% Cu containing Nd-rich TJP 

(Cuhigh-rich), were observed. The Culow-rich TJP was the stable h-Nd 2O 3, but the Cuhigh-rich TJP 

was the metastable C-Nd 2O 3 phase. The thickness and Fe content of Nd-rich GBP was increased 

with increasing Cu content because the oversaturated Cu atoms in the GBP substitutes with the Fe 

atoms near the GBP//Nd 2Fe 14B interfaces. As a result, the magnetic decoupling through the Nd-rich 

GBP was deteriorated and the coercivity was decreased when the Cu content of the magnet is high. 

[1] F. Vial, F. Joly, E. Nevalainen, M. Sagawa, K. Hiraga, and K. T. Park,.J. Magn. Magn. Maters. 242-245, 

1329 (2002). [2] W. F. Li, T. Ohkubo, T. Akiya, H. Kato, K. Hono, J. Mater. Res. 24, 413 (2009). [3] M. Matsuura, S. 

Sugimoto, T. Fukada, R. Goto, N. Tezuka, Journal of Physics: <strong>Conference</strong> Series. 200, 082019 (2010).

RO02 

Effects of the D yH 3 and D y2O 3 powder addition on the magnetic and 

microstructural properties of Nd-Fe-B sintered magnet 

Kyoung-hoon Bae 1 , Tae-hoon Kim 1 , Seong-rae Lee 1 *, Seok Namkung 2 and Tae-suk 

Jang 2 


2 Sunmoon University, Korea 

Effective way for enhancing the magnetic properties as well as saving the Dy content in the Nd-Fe-B based 

magnet is to develop the core-shell microstructure using the Dy 2O 3, DyF 3 or DyH3 powder doping [1, 2]. The 

DyH 3-doped magnet shows the most improved results [2]. However, the role of DyH 3 powder has not been 

identified yet. In this study, we investigated the magnetic and microstructural changes of the DyH 3-doped 

(2.4 wt.%) Nd 27.68Dy 4.89Febal.B 1.0M 2.4 (wt.%) sintered magnet comparing with those of the Dy 2O 3-doped (2.0 

wt.%) magnet. The coercivity of Dy 2O 3-doped magnet slightly increased (30.13→30.71 kOe) with a little 

remanence reduction (11.59→11.56 kG) comparing with the undoped magnet. However, the coercivity of the 

DyH 3-doped magnet increased (30.13→31.9 kOe) without sacrificing remanence (11.59→11.6 kG). Coreshell 

microstructure was well developed when the DyH 3 powders were added comparing with the Dy 2O 3doped 

magnet. The hydride powder doping enhanced the diffusion of Dy because the dissolution of the 

hydrogen in the Nd 2Fe 14B increased the lattice parameter and the point defects. The hydride was also known as 

a solid lubricant role at the grain boundaries [3]. As a result, the core-shell microstructure and the (00L) grain 

alignment of the DyH 3-doped magnet was more developed than those of Dy 2O 3-doped magnet. 

[1] S. E. Park, T. H. Kim, S. R. Lee, D. H. Kim, S. Namkung, and T. S. Jang, IEEE. Tran. Magn. 47, 10 

(2011). [2] G. Yan, P. J. McGuiness, J. P. G. Farr, and I. R. Harris, J. Alloys Compd. 491, L20 (2010). [3] 

S. Guo, R. J. Chen, Y. Ding, G. H. Yan, D. Lee, and A. R. Yan, J. Phys.: Conf. Ser. 266, 012030 (2011). 

RO03 

Magnetic properties of nano-composite Nd-Fe-B thick-film magnets 

prepared by vacuum arc deposition 

Tomoaki Tsutsumi 1 , Masaki Nakano 1 *, Takeshi Yanai 1 , Fumitoshi Yamashita 2 and 

Hirotoshi Fukunaga 1 

1 Nagasaki University, Japan 

2 MInebea Co. Ltd., Japan 

In order to upgrade the torque of the small motor comprising a multi-polarly magnetized 

rotor with isotropic thick-film magnets [1], enhancement in remanence of the isotropic thickfilm 

is indispensable. We, therefore, prepared nano-composite Nd-Fe-B/Alpha-Fe isotropic 

thick-films by using a vacuum arc deposition method [2]. This contribution reports the effect 

of the composition and the power of arc deposition on the magnetic properties. Samples 

were prepared by using several targets with the compositions of NdXFe 14B + Nb 0.5 at.% (X 

=1.4~2.0). The voltage and capacitance varied in order to control the power range between 

11 and 44 J. As the power was fixed at 44 J, use of a Nd 1.6Fe 14B + Nb 0.5 at. % target enabled 

us to obtain the highest (BH)max value. Although the deposition rate decreased from 

approximately 20 to 5 microns per hour due to the power reduction from 44 to 11 J, the value 

of (BH)max could be improved by approximately 15 kJ/m3 at the target composition of 

Nd 1.6Fe 14B + Nb 0.5 at. %. Resultantly, we succeeded in obtaining a 29 micron-thick Nd-Fe-B 

thick-films with the remanence, coercivity and (BH)max values of 0.92 T, 390 kA/m and 79 

kJ/m3, respectively. 

[1] F. Yamashita et al., IEEE Trans. Magn. 46, 2012 (2010). [2] M. Nakano et al., J. Appl. Phys. 109, No.7, 07A755-1 (2011). 

RO04 

Corrosion resistance and corrosion behaviors of sintered rare-earth 

magnets in different corrosive environments 

Anhua Li*, Wei Li, Jiajie Li, Haibo Feng, Zhaohui Guo and Minggang Zhu 

Division of Functional Materials, Central Iron & Steel Research Institute, China 

Sintered rare-earth magnets possessing outstanding magnetic properties are widely applied 

in many fields. However, corrosion resistance has been a problem with the magnets owing 

to the high chemical activity of the phases rich in rare earth elements [1]. The Nd-rich 

phases of the Nd-Fe-B magnets can react with water vapor and oxygen in a damp and 

humid atmosphere. The electro-chemical corrosion occurs for Nd-Fe-B magnets in a high 

humidity atmosphere because of the difference of corrosion potential between the matrix 

Nd 2Fe 14B phase and the boundary Nd-rich phase [2]. In this article, Corrosion resistance 

of sintered Nd-Fe-B and Sm-Co magnets was investigated in steady-state damp heat 

(HH), neutral salt spray (NSS) and pressure cooker (PCT) climates. The effects of alloy 

composition and different corrosive environments on magnetic flux loss were discussed. 

It shows that the corrosion rates of sintered Nd-Fe-B magnets in HH and NSS climates 

exhibit a obvious parabolic trend, flux loss in the above three kinds of climates have a 

approximate linear trend. The corrosion resistance of sintered Nd-Fe-B magnets can be 

improved by Dy partially substitution for Nd and minor Co addition. The sintered Sm-Co 

magnets show very good corrosion resistance in the above three kinds of climates. 

Sintered rare-earth magnets; corrosion resistance; corrosion behavior; different corrosive 

environments 

RO05 

RO06 

RO07 


Effects of grain size and interface state on the coercivity in Nd-Fe-B/ 

Nd thin films 

Kunihiro Koike 1*, Takanao Kusano 1 , Daisuke Ogawa 1 , Mizuno Yoshiyuki 1 , Miyazaki 

Takamichi 2 , Yasuo Ando 2 and Hiroaki Kato 1 

1 Graduate School of Science and Engineering, Yamagta University, Japan 


High coercivity in sintered Nd-Fe-B magnets is the crucial subject, especially in view of a 

high demand for developing Dy-saving magnets [1]. In order to approach this matter, the 

grain refinement and the interfacial microstructure control are known long to be the promising 

methods [2, 3]. In this work, the effect of Nd coating on the coercivity has been investigated 

in the Nd 2Fe 14B thin films with different grain sizes. As the Nd 2Fe 14B layer thickness tNFB 

was decreased from 70 nm to 5 nm, the coercivity exhibited a gradual increase behavior from 

6.5 kOe to 16 kOe, and from 17.5 kOe to 26.2 kOe for the Nd-Fe-B and Nd-Fe-B/Nd films, 

respectively. It should be noted that the amount of Hc increase by the Nd coating was about 10 

kOe irrespective of Nd-Fe-B layer thickness tNFB. AFM observations showed that the average 

Nd2Fe14B particle size of the tNFB = 5 nm film is about 60 nm, which is much smaller than 

the critical size for the single domain in the Nd2Fe14B phase. These results therefore suggest 

that a proper interface state is extremely important to achieve high coercivity not only in larger 

grain system but also in smaller particle one. 

[1] S. Sugimoto, Proc. on the 21th Int. Workshop on Rare-earth Permanent Magnet and their 

Applications, Bled, Slovenia (2010) 103. [2] K. H. Muller, D. Eckert, A. Handstein, P. Nothnagel, and J. 

Schneider, J. Magn. Magn. Mater., 83, (1991) 195. [3] J. D. Livingston, J. Appl. Phys., 57, (1985) 4137. 

Interface state and coercivity in Nd-Fe-B/Dy films 

Jin Umezawa 1 , Yoshiki Sakai 1 , Kunihiro Koike 1 *, Daisuke Ogawa 1 , Yoshiyuki 

Mizuno 1 , Takamichi Miyazaki 2 , Yasuo Ando 2 and Hiroaki Kato 1 

1 Graduate School of Science and Engineering, Yamagta University, Japan 


It is believed that the Nd-rich phase plays an important role for the coercivity emhancement 

in the Nd-Fe-B magnets [1-2]. In the case of Dy-diffusion-processed Nd-Fe-B magnets [3], 

however, it is still not clear whether only the Dy-rich shell or both Dy-shell and the Nd-rich 

phase is indispensible for the high coercivity. Therefore, we fabricated a model interface 

system, which consists of the Nd 2Fe 14B layer with the Dy and Nd overlayers in order to study 

the relationship between microstructure near the interface and the coercivity. Nd 2Fe 14B particles 

with the c-axis normal to the film plane were constructed by using HV or UHV sputtering 

systems. We introduced high-melting-point bcc metals, Ta or Mo, as an underlayer on the 

heat-resistant glass or sapphire c-plane single-crystal substrates. When the temperature of the 

substrate during a deposition of the 1 μm thick Nd-Fe-B layer was 620°C, the demagnetization 

curve of this film without rare-earth overlayers exhibited a nice squareness with coercivity Hc = 

3.3 kOe. On the other hand, preliminary experiments on the post-annealed Nd-Fe-B films with 

the Dy overlayer showed a significant increase in Hc of up to above 15 kOe. 

[1] K. H. Muller, D. Eckert, A. Handstein, P. Nothnagel, and J. Schneider, J. Magn. Magn. Mater., 

83, (1991) 195. [2] F. Vial, F. Joly, E. Nevalainen, M. Sagawa, K. Hiraga, and K.T. Park, J. Magn. 

Magn. Mater., 242-245, (2002) 1329. [3] H. Nakamura, K. Hirota, M. Shimao, T. Minowa, and M. 

Honshima, IEEE Trans. Magn., 41 (2005) 3844. 

Investigation on the magnetic and crystalline structures of die-upset 

Nd-Fe-B magnets 

Yikun Fang 1 *, Wei Li 1 , Xiaolu Yin 2 , Zhaohui Guo 1 , Minggang Zhu 1 and Sy-hwang Liou 2 

1 

Division of Functional Materials Research, Central Iron and Steel Research 

Institute,Beijing 100081, China 

2 

Department of Physics and Astronomy and Nebraska Center for Materials and 

Nanoscience, University of Nebraska- Lincoln, Lincoln, NE 68588, USA 

Die-upsetting is used to prepare anisotropic Nd-Fe-B magnets due to high magnetic texture in which the 

c-axis of Nd2Fe14B grains is parallel to the loading direction. [1] Though many papers have reported on the 

structures of high-textured Nd-Fe-B magnets [2-5], there are still some issues needed to be clarified, such as 

how about the uniformity of the magnetic structures and how to improve the uniformity. In this paper, x-ray 

diffraction (XRD) and magnetic force microscopy (MFM) are used to reveal the crystalline and magnetic 

structures of die-upset Nd 13.62Fe 75.70Co 4.45B 5.76Ga 0.47 magnets. It is found that the ratio of the XRD peak intensity 

I(006)/ I(105) from center to edge of the sample decreases from 1.86 to 1.35. The magnetic configurations of 

the central of the sample are typical interaction domains. The interaction domains are formed due to the strong 

inter-granular exchange interaction and magnetostatic interaction between grains. However, on the edge of 

the sample the non-interaction domains present. The XRD and MFM results may relate to the non-uniformity 

of the effective strain that generated during the die-upsetting process. This indicates we need to improve the 

uniformity of the strain distribution for the development of high-performance magnets. 

[1] R. W. Lee, Appl. Phys. Lett. 46, 790 (1985). [2] K. Khlopkov, O. Gutfleisch, D. Hinz, K.-H. Muller, and L. 

Schultz, J. Appl. Phys. 102, 023912 (2007). [3] Y. G. Liu, L. Xu, Q.F. Wang, W. Li, and X. Y. Zhang, Appl. Phys. 

Lett. 94, 172502 (2009). [4]R. Zhao, W. C. Zhang, J. J. Li, H. J. Wang, M. G. Zhu, and W. Li, J. Magn.16, 294 (2011). 

[5] Y. K. Fang, X. L. Yin, R. Zhao, S. Valloppilly, W. Li, M. G. Zhu, S. H. Liou, J. Appl. Phys.(2012) in press. 


Poster Thursday



RO08 

A novel approach -microwave assisted sintering - for preparation of 

high performance permanent magnets 

Dimitrios G Niarchos 1 *, Margarit Gjoka 1 , Eamon Devlin 1 , George Hadjipanayis 2 , 

Amparo Borrell Tomas 3 , Maria Dolores Salvador Moya 3 and Felipe L Penaranda-foix 4 


2 Department of Physics and Astronomy, U of Delaware, Newark, DE, USA 

3 Institute of Materials, Technology Polytechnic University of Valencia, Camino de Vera, s/n 46022, Spain 

4 School of Communication, 4 School of Telecommunication, Polytechnic University of Valencia, Camino 

de Vera, s/n 46022, Spain 

A large portion of the cost for the fabrication of permanent magnets is due to the energy needed for 

sintering. Any improvement for the sintering process with respect to time and energy will reduce the cost 

and will increase the market of permanent magnets considerably. Based on the most recent development in 

microwave applications reported by R. Roy (1) , where it was demonstrated that sintering of metal powders- 

a surprising application- is possible with microwaves (in view of the known fact that bulk metals reflect 

microwaves), we have employed microwaves to sinter Nd-Fe-B at a fraction of time and energy, compared 

to the conventional resistive/radiant heating in excess of 1000 0C for many hours, and in many cases 

homogenizing also at high temperatures. Microwave heating is a volumetric heating involving conversion 

of electromagnetic energy into thermal energy, which is instantaneous, rapid and highly efficient. In this 

work, we will present the emerging possibilities for sintering Nd-Fe-B and Sm-Co permanent magnets as 

well as the opening of new possibilities for metal bonded magnets by employing microwave radiation, that 

is already used for ferrites by various groups. Supported by the project NANOPERMAG of the EU 

RERERENCES 1. R. Roy, D. Agrawal, J. Cheng and S. Gedevanishvili, Nature, 399, pp.668-670, 1999 

RO09 

Preparation of Nd-Fe-B thin films with columnar structure and their 

structure and magnetic properties 

Shota Suzuki, Yuki Hatayama and Toshiyuki Shima 

Tohoku Gakuin University, Japan 

The addition of heavy rare earth elements is essential for Nd-Fe-B sintered magnet 

to obtain high-performance characteristic at high temperature. However, a reduction 

of these additive elements is strongly required since the price of these elements has 

increased in recent years. It was reported that the additive elements such as Cu and 

Ga were diffused and concentrated into the grain boundary phase (GBP) [1, 2], and 

the magnetic coupling between the main phases is thought to reduce by the GBP. 

In order to improve the hard magnetic properties, therefore, the control of the GBP 

is indispensable. In this study, the Nd-Fe-B thin films with well-defined columnar 

structure have been prepared and structure and magnetic properties have been also 

investigated. The samples were prepared by using an ultra-high vacuum sputtering 

system. The thickness of the Nd-Fe-B layer was varied in the range of 50 ~ 300 nm. 

From the X-ray diffraction patterns, the peaks from Nd2Fe14B (004), (006), and (008) 

were observed for all the samples. This indicates that the films grew with a strong (001) 

texture. A good magnetic squareness and relatively high coercivity of 8.3 kOe were 

obtained for the Nd-Fe-B films with t = 100 and 200 nm. 

[1] C. Y. You, Y. K. Takahashi, K. Hono, J. Appl. Phys., 108, (2010) 043901. [2] T. Sato, H. Kato, T. 

Shima, Y. K. Takahashi, K. Hono, J. Magn. Magn. Mater., 323 (2011) 163-166. 

RO10 

Microstructure of (Nd,Dy)-Fe-B permanent magnet by spark plasma 

sintering 

Sun Yong Song, Jin Woo Kim and Young Do Kim* 

Division of Materials Science and Engineering, Hanyang University, Korea 

Sintered (Nd,Dy)-Fe-B magnets are widely used in various parts such as motor, generators, 

actuators, and so on because of their outstanding magnetic properties. (Nd,Dy)-Fe-B sintered 

magnets are generally composed of the Nd 2Fe 14B hard magnet phase as a matrix and a Ndrich 

phase at the triple junction [1,2]. However, typical sintered (Nd,Dy)-Fe-B magnets are 

limited in their applications due to low curie temperature[3]. Many researchers have shown 

that the magnetic properties of (Nd,Dy)-Fe-B magnets are structure sensitive, and dependent 

on the distribution of the rare-earth-rich phases, average grain size and size distribution. 

Particularly the grain size of Nd 2Fe 14B was essentially important for high magnet properties. 

In this study, we focused on controlling of the grain size to enhance magnetic properties 

by the spark plasma sintering process. The starting powder with the composition of 

Nd 13Dy 2Fe 76.2TM 2.8B 6 was prepared by strip casting and jet milling process. The raw powder 

was pre-sintered for preventing collapsibility of anisotropy. After the pre-sintering, (Nd,Dy)- 

Fe-B magnet was fabricated by spark plasma sintering process under 30 MPa with various 

temperatures. Consequently we had made the (Nd,Dy)-Fe-B sintered magnet with grain size 

of 5.9 μm. The grain size was effectively controlled by spark plasma sintering. 

[1] M.Sagawa,S.Fujimura,N.Togawa,H.Yamamoto,Y.Matsuura,J.Appl.Phys.55 (1984)2083-2087. 

[2] H.J.Wang,Z.H.Guo,A.H.Li,X.M.Li,W.Li,J.Magn.Magn.Mater.303(2006) e392-e395. [3] W.F.Li,T. 

Ohkubo,K.Hono,M.Sagawa,J.Magn.Magn.Mater.321(2009) 1100-1105. 


RO11 

Effect of small Dy-alloy powder additions on the coercivity of NdFeB 

sintered magnets 

MINWOO LEE 

Sunmoon University, Korea 

Recently, demand of high performance NdFeB sintered magnets is rapidly increasing 

mostly due to expansion of wind generators and hybrid electric vehicles. For traction 

motors of hybrid electric vehicles, the coercivity of NdFeB sintered magnet is 

required to exceed 25 kOe. For such high coercivity, partial substitution of Dy for Nd 

in Nd 2Fe 14B of NdFeB sintered magnet is practically inevitable, with the sacrifice of 

magnetization value and the increase of material cost. Because the price of Dy is very 

high and keeps increasing due to its scarcity, it is important to reduce the amount of Dy 

in NdFeB magnets as much as possible without losing coercivity. Recent researches on 

NdFeB magnets, therefore, are mainly focused on Dy-saving methods. In this study, as 

an effort to develop a Dy-saving method, small Dy-TM alloy powder was mixed with 

NdFeB magnet powder and then a sintered magnet was fabricated by a conventional 

process. When 1.9 wt% of DyCo powder was mixed, the coercivity of the sintered 

magnet increased about 4 kOe, indicating 20% of Dy saving effect. More experimental 

results will be discussed in this presentation. 

RO12 

Coercivity of near single domain size Nd-Fe-B-type alloy particles 

Hae-woong Kwon 1 and J H Yu 2 


2 KIMS, Korea 

Fine particles of Nd-Fe-B alloy in near single domain size have increasingly found new 

applications for high performance micro-magnet. However, because of high oxygenaffinity 

and high specific surface area, the ultra-fine Nd-Fe-B-type particles are readily 

oxidized in air, hence causing a radical coercivity loss. In the present study, an ultrafine 

Nd-Fe-B-type particles in near single domain size was prepared by ball milling of 

HDDR-treated Nd12.5Fe80.6B6.4Ga0.3Nb0.2 alloy. The prepared near single domain 

size Nd-Fe-B-type powder ( 0.3 um) had high coercivity over 9 kOe. However, the 

coercivity was radically reduced as the temperature increased in air (< 2 kOe at 200 

°C). Room temperature long-term stability of coercivity of the fine powder in air was 

investigated for 1 month, and the coercivity was decreased by rate of 0.5 kOe/week. 

Feasibilty of surface nitrogenation of the fine powder for improving the long-term 

stability of coercivity was studied. Long-term stability of coercivity of the nitrogenated 

fine powder was improved markedly. The nitrogenated powder showed no coercvity 

reduction even after 1 month in air at room temperature. In this article, the surface 

passivation of near single domain size Nd-Fe-B-type particles by nitrogenation for 

improving long-term stability of coercivity is to be discussed. 

RO13 

Effect of annealing temperature on microstructure, magnetic 

properties and corrosion resistance of NdFeB/α-Fe nanocomposite 

magnets 

Minxiang Pan, Pengyue Zhang*, Hongliang Ge, Hangfu Yang and Qiong Wu 

Magnetism key laboratory of Zhejiang Province, China Jiliang University, 310018 

Hangzhou, China, China 

REFeB based nanocomposite alloys have attracted much attention in both the scientific 

community and bonded magnet industry. However, lower coercivity and poor corrosion 

resistance limit their applications. Both the practical coercivity and corrosion resistance 

are sensitive to the character of phase constitute in the microstructure. Sintered NdFeB 

magnet is the poor corrosion resistance due to the presence of the highly corrosive Ndrich 

phase. As no Nd-rich phase is formed in the NdFeB/α-Fe nanocomposite magnets, 

these alloys should be more corrosion resistant than the NdFeB sintered magnet. In this 

work, the effects of annealing temperature on the microstructure, magnetic properties 

and corrosion resistance in NdFeB/α-Fe alloys were investigated. It is shown that 

after heat treatment, the alloys mainly consist of two phases: a hard magnetic phase of 

Nd 2Fe 14B (space group P 42/mnm) and a soft magnetic phase of α-Fe (Im3m), and that 

no other phases are identified. Moreover, the optimum corrosion resistance of NdFeB/ 

α-Fe magnets was observed with the annealing temperature at 610°C. Keywords: 

Nanocomposite, Magnetic property, corrosion resistance 

*E-mail: Zhang_Pengyue@cjlu.edu.cn.

RO14 

Effect of magnetic heat-treatment on magnetic properties and 

corrosion behavior of Nd 6Fe 72-xCo xB 22 (x=10, 20, 30) nanocomposite 

ribbons 

Qiong Wu, P.z. Zhang*, M.x. Pan, Z.s. Wang and H.l. Ge 

China Jiliang University, China 

Nanocomposite rare-earth magnets consisting of a hard and a soft magnetic phase have 

attracted considerable attention because the remanence enhancement in exchange coupled 

nanocomposite alloys has potential importance as a way to achieve high values of the 

maximum energy product (BH)max. It is well established that the magnetic properties of 

nanocrystalline two-phase magnets are strongly dependent on its microstructure. A uniform 

microstructure and a well-coupled grain interface should be two essential conditions 

for a well-performing nanocomposite. Magnetic annealing has been tried to perfect the 

microstructure and enhance the magnetic properties. In this paper, Nd 6Fe 72-xB 22(x=10,20,30) 

ribbons were heat-treated with or without an external magnetic field of 3 kOe in argon 

atmosphere in the temperature range of 600-750°C for 10 min. It is found that magnetic heattreatment 

enhances both coercivity and remanence ratio of the Nd 6Fe 72-xCoxB 22(x=10,20,30) 

ribbon, and decrease the annealed temperature obtained the optimum magnetic properties 

due to the uniform distribution and preferential orientation of α-Fe and Nd 2Fe 14B grains. The 

corrosion behavior of Nd 6Fe 72-xCoxB 22(x=10, 20, 30)nanocomposite ribbons with or without 

an external magnetic field is discussed in detail. 

Q.G. Ji, B.X. Gu, S.L. Tang et al. J.Magn.Magn.Mater. 257 (2003) 146. 

RO15 

Study on magnetization reversal behavior for the annealed Nd2Fe14B/ α-Fe nancomposite alloys 

Pengyue Zhang 1 , Minxiang Pan 1 , Hongliang Ge 1 , Luke Yang 1 , Ming Yue 2 and 

Weiqiang Liu 2 

1 

College of Materials Science & Engineering, China Jiliang University, Hangzhou 

310018, China, China 

2 

College of Materials Science & Engineering, Beijing University of Technology, 

Beijing 100124, Chin, China 

Effect of thermal annealing on the magnetization reversal behavior of α-Fe/Nd 2Fe 14B 

alloys has been investigated. A drastic increase of the remanence Mr from 0.67T up 

to 0.87T and remanence ratio Mr/Ms from 0.66 up to 0.76, respectively, is observed 

in the α-Fe/Nd 2Fe 14B alloys annealed at 610 oC as compared with the as-quenched 

sample. Whereas the further annealing at 680 oC results in a strongly increase of the 

corecivity Hc as high as 491 kA/m but a slight decrease in Mr. The analysis result of 

the magnetization reversal behavior shows that the maximum value of the integrated 

recoil loop area about 1.58 kJ/m 3 is obtained in the α-Fe/Nd 2Fe 14B alloys at the 

annealing temperature of 610 oC, significantly lower than other annealed samples. 

This indicates a significant advantage for the application of this material as permanent 

magnets in electrical machines and generators due to a low energy loss. Keywords: 

Nanocomposite; Magnetization reversal behavior; Recoil loop 

*E-mail: Zhang_Pengyue@cjlu.edu.cn. 

RP01 

Construction of a versatile neutron-scattering spectrometer 

HERMES-E using renovated Ge monochromator crystals 

Haruhiro Hiraka 1 *, Kenji Ohoyama 1 , Manabu Ohkawara 1 , Naoki Murakami 1 , Yasuo 

Yamaguchi 1 , Kazuma Okubo 2 , Michiro Furusaka 2 , Yoshiaki Kiyanagi 2 , Shin Ae Kim 3 , 

Chang Hee Lee 3 , Kohei Morishita 4 , Kazuo Nakajima 4 and Kazuyoshi Yamada 5 

1 


2 

Division of Quantum Science and Engineering, Graduate School of Engineering, 

Hokkaido University, Japan 

3 

HANARO, Korea Atomic Energy Research Institute, Korea 

4 

Graduate School of Energy Science, Kyoto University, Japan 

5 

Advanced Institute for Materials Research, WPI, Tohoku University, Japan 

We propose an efficient way, which increases a number of neutron spectrometers 

in a research-reactor facility. The first key is to making use of a characteristic Gecrystal 

monochromator, which discretely emits Bragg reflections to different scattering 

angles at the same time. The second is to save the instrumental space by using curved 

and deformed Ge-wafer crystals as a monochromator or an analyzer. Indeed, we are 

planning to double a neutron-powder diffractometer of Tohoku University (HERMES 

[1]) that is working at a research reactor JRR-3, Tokai, Japan; a versatile neutronscattering 

spectrometer HERMES-E is now under construction next to HERMES. 

[1] K. Ohoyama et al., Jpn. J. Appl. Phys. vol. 37 (1998) 3319. 

RP02 

NMR study of the phase transition behavior in Ce3Co4Sn13 

Chin Shan Lue, H. F. Liu and C. N. Kuo 

Physics, National Cheng Kung University, Taiwan 

RP03 

RP04 


We present a study of the phase transition behavior in Ce 3Co 4Sn 13 using 59Co nuclear 

magnetic resonance (NMR) spectroscopy. The quadrupole splitting, Knight shift, and 

spin-lattice relaxation rate (1/T1) below and above the phase transition temperature 

To have been identified. All measured NMR quantities exhibit pronounced features at 

around To=155 K except for the Knight shift. It thus excludes the magnetic origin for 

the observed transition. In addition, the x-ray diffraction results below and above To 

confirm the absence of a crystal structural change, suggesting that the peculiar phase 

transition is possibly driven by the charge-density-wave (CDW) formation. As a matter 

of fact, the double-peak feature in the 59Co NMR central line smears out below To 

which can be associated with the spatial modulation of the electric field gradient (EFG) 

due to incommensurate CDW superlattices. Furthermore, a distinct peak found in the 

spin-lattice relaxation rate near To can be accounted for by the thermally-driven normal 

modes of the CDW. 

Analysis of 1/f noise characteristics of magneto-optical Kerr effect 

measured from Co/Pt and NiFe/Pt multilayers thin film 

Djati Handoko, Sang-hyuk Lee and Dong-hyun Kim* 

Physics Department, Chungbuk National University, Korea 

We have investigated 1/f noise characteristic of the polar and longitudinal magnetooptical 

Kerr effect (MOKE). The hand-made MOKE measurement system was set 

using diode laser as a light source. Si photodetector was used as a detector where the 

bias has been systematically controlled. To increase a signal-to-noise ratio, the laser 

light was modulated with the lock-in amplification frequency referenced from the 

mechanical chopper in the frequency ranges up to 4 kHz. Noise characteristics of the 

optical/electrical/mechanical error were systematically examined. To separate the noise 

contribution from the ferromagnetic layer and from the intrinsic measurement error, 

various configurational changes were made for the lock-in frequency as well as the bias 

voltage of the Si photodetector. Magnetic noise properties under a different magnetic 

field were systematically investigated as well. For a perpendicular anisotropy sample, 

Co/Pt multilayer film was investigated while for an in-plane anisotropy sample, NiFe/ 

Pt bilayer film was investigated. The noise characteristics with respect to the multilayer 

thickness variations were examined as well. The 1/f noise characteristics observed for 

a wide range regardless of the lock-in frequency change or the film thickness change 

implies that there might be a universal characteristics in the MOKE signal noise, 

arising from the sample itself. 

Photoemission electron microscopy of three-dimensional magnetization 

configurations in core-shell nanostructures 

Judith Kimling 1 , Florian Kronast 2 , Stephan Martens 1 , Tim Boehnert 1 , Michael 

Martens 1 , Julia Herrero Albillos 2 , Logane Tati Bismaths 2 , Ulrich Merkt 1 , Kornelius 

Nielsch 1 and Guido Meier 1 * 

1 University of Hamburg, Germany 

2 Helmholtz-Zentrum Berlin fuer Materialien und Energie, Germany 

We present a photoemission electron microscopy method that combines magnetic imaging of the 

surface and of the inner magnetization in three-dimensional core-shell nanostructures [1]. The 

structure investigated consists of a cylindrical nickel core that is completely surrounded by a shell of 

iron oxide and silicon oxide layers. The method enables one to image the magnetization configuration 

of the nickel core even though the shell is thicker than the mean-free path of the photoelectrons. 

Characteristic L 3 and L 2 edges can be observed not only in the yield of the photoelectrons emitted 

from the surface of the nanostructure but also in its shadow. X-ray magnetic circular dichroism in 

the electron yield of the x rays absorbed and transmitted by the multilayered nanowire allows for the 

individual imaging of the magnetization configurations of the iron oxide tube and the nickel core. The 

method suggests novel approaches for the characterization of the magnetic and material properties of 

complex three-dimensional nanostructures. Financial support by the DAAD via the Project 50725506 

and by DFG via the SFB 668 and the GrK 1286 as well as the Forschungs- und Wissenschaftsstiftung 

Hamburg via the Exzellenzcluster “Nano-Spintronik” is gratefully acknowledged. 

[1] J. Kimling, F. Kronast, S. Martens, T. Boehnert, M. Martens, J. Herrero-Albillos, L. Tati- 

Bismaths, U. Merkt, K. Nielsch, and G. Meier, Phys. Rev. B 84, 174406 (2011). 


Poster Thursday


RP05 


Development of high-field ESR system using SQUID magnetometer 

and its application to measurement under high pressure 

Takahiro Sakurai 1 *, Kohdai Fujimoto 2 , Susumu Okubo 3 , Hitoshi Ohta 3 and Yoshiya 

Uwatoko 4 

1 Center for Supports to Research and Education Acti, Kobe University, Japan 



4 Institute of Solid State Physics, University of Tokyo, Japan 

We have developed high-field ESR system using commercial SQUID magnetometer, in 

which ESR is observed as a change of magnetization. [J. Phys.: Conf. Ser. 334 (2011) 

012058.] The advantage of this method as compared with conventional high-field ESR is 

that the measurement can be done very easily. Moreover, the macroscopic magnetization 

measurement can be made simultaneously. Although the sensitivity of this system is 

lower than that of ESR system using cavity, it is comparable with that of transmission 

type ESR system. Recently, we have succeeded in performing ESR measurement under 

high pressure by this ESR system. The pressure is generated by a widely used clamped 

type piston-cylinder pressure cell whose cylinder is made of non-magnetic CuBe alloy. 

Since all inner parts are made of zirconium oxide, the electromagnetic wave can be 

introduced into the sample space. Therefore, we can measure the magnetic moment of 

sample and obtain ESR signal under pressure. The pressure is available up to 1.5 GPa. 

This is the easiest ESR system which gives us pressure dependence ESR spectra as far 

as we know. The setup of this system and several results will be shown in detail. 

RP06 

Alternating magnetic force microscopy: direction detectable imaging 

of static and alternating magnetic field with high spatial resolution 

Hitoshi Saito 1 , Ito Ryoichi 1 , Kodai Hatakeyama 1 , Zhenghua Li 2 , Genta Egawa 1 and 

Satoru Yoshimura 1 

1 Graduate School of Engineering and Resource Science, Akita University, Japan 

2 Venture Business Laboratory, Akita University, Japan 

We have developed a new functional MFM named as “Alternating Magnetic Force Microscopy 

(A-MFM)” which enables us to measure static and alternating magnetic fields with the polarity of 

field direction [1-5]. A-MFM utilized the frequency modulation of a cantilever oscillation generated 

by an off-resonance alternating magnetic force between a magnetic sample and a magnetic tip. The 

alternating magnetic force was extracted by a lock-in amplifier for the frequency demodulated signal 

of the cantilever oscillation. For the static magnetic field from a sample, a soft magnetic tip which ware 

driven by an AC magnetic field was used to detect the static magnetic field with high sensitivity. On the 

other hand, for the alternating magnetic field from a sample, such as a magnetic writing head, a hard 

magnetic tip was used. A-MFM can measure a magnetic force without surface short-range forces and 

directly detect the direction of perpendicular magnetic fields. When the tip-sample distance became 

short, spatial resolution was improved. In the conference, we will demonstrate high performance of 

A-MFM and show high-resolution magnetic field images with a resolution of less than 10 nm for highdensity 

recording media and magnetic writing heads. This study was supported by SENTAN, JST. 

[1] H. Saito et al. J. Appl. Phys. 105 (2009) 07D524, [2] H. Saito et al. J. Appl. Phys. 107 (2010) 

09D309, [3] W. Lu et al. Appl. Phys. Lett. 96 (2010) 143104, [4] W. Lu et al. IEEE Trans. Magn. 46 

(2010) 1479, [5] H. Saito et al. J. Appl. Phys. 109 (2011) 07E330 

RP07 

30 T pulsed-high-magnetic-field and element-selective magnetization 

studies using soft x-ray magnetic circular dichroism 

Yasuo Narumi 1 *, Tetsuya Nakamura 2 , Misaki Hayashi 1 , Hiroyuki Nojiri 1 , Kenji Kodama 3 , Toko 

Hirono 2 , Wataru Ito 4 , Rie Umetsu 1 , Ryosuke Kainuma 5 , Koichi Kindo 6 and Toyohiko Kinoshita 2 


2 Japan Synchrotron Radiation Research Institute/SPring-8, Japan 

3 Department of Mechanical Engineering, Nara National College of Technology, Japan 

4 Department of Materials and Environmental Engineering, Sendai National College of Technology, Japan 



We demonstrate the applicability of 30 T pulsed-high-magnetic-field to observe magnetic circular dichroism 

(MCD) of antiferromagnetic compounds in soft x-ray energy regions, in which there are magnetically important 

transition energies, L-edge of 3d transition metal and M-edge of 4f rare earth elements. We have developed a 

specially designed pulse magnet equipped with an ultra-high-vacuum environment and a portable capacitor 

bank for synchrotron soft x-ray experiments [1]. A time-resolved total electron yield method is used to record 

x-ray absorptions in synchronization with pulsed-high-magnetic-fields and periodic switching of circularly 

polarized soft x-rays. We have measured elements-selective magnetizations of Ni, Co and Mn in the NiCoMnIn 

alloy which shows a large field-induced strain accompanied by a drastic change of the magnetization [2]. All 3d 

transition metal elements show steep non-linear increases of the MCD intensities around 15 T corresponding to 

the metamagnetic transition. This high-magnetic-field soft x-ray MCD result directly evidences that all magnetic 

elements contribute to the field-induced shape memory effect in the NiCoMnIn alloy. 

[1] T. Nakamura et al., Appl. Phys. Express 4, 066602 (2011). [2] R. Kainuma et al., Nature 439, 957 (2006). 


RP08 

Imaging magnetic responses of nanomagnets by X-ray PhotoEmission 

Electron Microscopy 

Florian Kronast 1 *, Julia Herrero-albillos 2 , Oliver Sandig 1 , Julia Kurde 1 , T Noll 1 , 

Florian Roemer 3 , Nina Friedenberger 3 and M Farle 3 

1 

Helmholtz Zentrum Berlin fur Materialien und Energie, Albert-Einstein-Str. 15, 

1 

2489 Berlin, Germany 

2 

Centro Universitario de la Defensa, Carretera Huesca s/n, Zaragoza, Spain 

3 

Universitat Duisburg-Essen, Lotharstr.1, 47048 Duisburg, Germany 

The Spin-resolved PhotoEmission Electron Microscope (SPEEM) is a permanently installed setup at 

the X-ray synchrotron radiation source BESSY, Helmholtz-Zentrum Berlin. The capabilities of excellent 

spatial resolution and an energy- and polarization-tunable light source make this end-station ideal for 

magnetic imaging and micro-spectroscopy with quantitative analysis. The application of magnetic fields 

while measuring significantly expands the technique of magnetic imaging. A dedicated magnetic sample 

holder incorporating both DC and AC magnetic field with additional temperature control has recently 

been developed. The SPEEM end-station, in combination with this novel sample holder enables the insitu 

control of the magnetic state and direct observation of the corresponding magnetic response. Two 

selected examples demonstrate these capabilities: magnetization curves of individual Fe nanocubes, 

and the local magnetic ac susceptibility in and microstructures as a function of temperature. In the latter 

example, a surprising onset of finite size effects at the micro-scale has been observed, with a significant 

reduction of the ordering temperature in microstructures compared to the extended film. These results were 

observed specifically as a result of these improvements in the PEEM technique. In combination with other 

possibilities, such as depth resolved imaging, new insights to magnetic nanostructures can be realized. 

RP09 

Development of high-sensitivity cantilever-detected ESR measurement 

using a fiber-optic interferometer. 

Yuki Tokuda 1 , Eiji Ohmichi 2 * and Hitoshi Ohta 3 


2 Graduate School of Science,, Kobe University, Japan 

3 Molecular Photoscienece Research Center, Kobe University, Japan 

Cantilever-detected high-frequency electron spin resonance (ESR) is a powerful method 

for terahertz ESR spectroscopy of a tiny magnetic sample at low temperature [1,2]. In this 

technique, a small magnetization change associated with ESR transition is detected as deflection 

of a sample-mounted cantilever. So far, we have succeeded in ESR detection at 370 GHz using 

a commercial piezoresistive microcantilever. The spin sensitivity was estimated to ~1012 spins/ 

gauss. In order to further increase the sensitivity, we adopt a fiber-optic-based detection system 

using a Fabry-Perot interferometer in place of piezoresistive system. Fabry-Perot cavity is 

formed between an optical-fiber end and microcantilever surface, and a change in interference 

signal, corresponding to the cantilever deflection, is sensitivity detected. This system is suitable 

for low-temperature and high-magnetic field experiments because of its compact setup and less 

heat dissipation. We will combine our fiber-optic detection system with a 15 T superconducting 

magnet and BWO light sources covering a wide frequency range 200-1200 GHz. Test 

measurement with Co Tutton salt is now in process to estimate the system performance. In the 

presentation, details of our experimental setup and test results will be presented. 

[1] E.Ohmichi, N. Mizuno, M. Kimata, and H.Ohta, Rev. Sci. Instrum. 79, 103903 (2008) [2] 

E.Ohmichi, and T.Osada, Rev. Sci. Instrum 73, 3022 (2002) 

RP10 

Study of the epitaxial growth and perpendicular magnetic domain 

structure of ordered FePt thin film on MgO substrate using HRTEM 

and electron holography 

W. H. Lee 1 , J. H. Yoo 2 , J. M. Yang 2 and J. K. Park 1 * 

1 

Department of Materials Science and Engineering, Korea Advanced Institute of 

Science and Technology, Korea 

2 

Measurement and Analysis Team, National Nanofab Center, Korea 

The epitaxial film of ordered FePt, showing the c-axis normal to the film plane, was 

successfully grown on top of MgO substrate using DC-magnetron co-sputtering technique. 

The electron holography study showed that a columnar epitaxial film displayed only a weak 

stray-field signal due to the presence of columnar boundaries. The growth of a continuous 

(full) epitaxial film however revealed characteristic Lorentz TEM images for the perpendicular 

magnetic domains. The electron hologram indicated the presence of the stray-fields of induction 

originating from the perpendicular magnetizations. It was shown that the sense of stray fields 

and thus the sense of perpendicular magnetizations could be determined by analyzing the 

contraction and expansion behavior of hologram fringes which were parallel to the reference 

fringes. Furthermore, direct hologram information was detected in a thicker epitaxial film by 

applying high resolution electron holography. Perpendicular magnetic domain structure was 

directly revealed in the unwrapped phase image and was confirmed by the measurement of the 

line profile of phase-shift. The estimation of the local strength indicated that the perpendicular 

induction strength was varying from about 0.33T to about 0.61T depending on the domain size. 

The variation of induction strength was due to a weak ordering of the film.

RP11 

Asteroid curve of GMR films on the practical substrate under the 

stress 

Kazuhiko Okita 1 , Kazushi Ishiyama 2 and Hideo Miura 3 

1 Industrial Instrumentation Division, Tohoku Steel Co., L7td., Japan 

2 Research Institute of Electrical Communication, Tohoku University, Japan 

3 Department of Nanomechanics, Graduate School of Engineering, Tohoku University, 

Japan 

Magnetic thin films usually have some of magnetostriction effect. After forming electric devices, 

this effect sometimes deteriorates the sensitivity of sensors such as read heads of hard disk drives, 

HDD, or the bit stability of memories such as magnetic random access memories, MRAM, 

through the inverse magnetostriction phenomenon. We need, therefore, to understand the 

magnetostriction effect on a film deposited on an actual wafer and the influence from the stress 

to it. In the previous paper, we showed the novel method of measuring the magnetostriction 

constant on the practical substrate [1]. In this paper, by using this method we measured the 

asteroid curves of the magnetic thin film of the giant magnetoresistance, GMR, on the practical 

wafer with varying applied stress on it. This result showed that the coercive force parallel to the 

easy axis, Hc, of a magnetic thin film with a negative sign of magnetostriction constant was 

decreasing with increasing tensile stress and the coercive force parallel to the hard axis, Ha, 

was also decreasing. For the film with the positive sign one, Hc and Ha were increasing with 

increasing tensile stress. And we showed the Hc was roughly proportional to the applied stress. 

[1] K. Okita, K. Ishiyama and H. Miura, 'Magnetostriction Measurement of GMR Films on the 

practical substrate', Journal of Physics, <strong>Conference</strong> Series 200 (2010) 112008 

RP12 

Micromagnetic study on the perturbative effect of magnetic force 

microscopy probes on 90° asymmetric Neel walls in a soft magnetic material 

Hironori Asada 1 *, Hidenori Kubo 1 , Hazrina Abu Seman 1 , Takashi Manago 2 and 

Hiromi Kuramochi 3 

1 

Yamaguchi University, Japan 

2 

Fukuoka University, Japan 

3 


It is important to clarify the dependence of perturbative effect of MFM probes upon probe parameters and 

experimental conditions[1]. In this study, 3D micromagnetic simulation has been performed to evaluate 

the perturbative effects on magnetization states and force gradient signals of 90° asymmetric Neel walls 

in a 100nm-thick patterned permalloy film. The signals are computed by varying the position of the probe 

assuming the stripe shape. The different signal distortions are observed depending upon the combination 

of the out-of-plane component of the magnetization direction of wall and the magnetization direction of 

the probe. In the parallel case, signal asymmetry originated from the asymmetric wall structure is enhanced 

and the normalized contrast defined as the difference of the maximum and minimum values of the signal 

divided by probe saturation magnetization(Ms) is increased. In the antiparallel case, signal asymmetry 

is suppressed and the normalized contrast is decreased. When probe Ms is increased further (antiparallel 

case), the out-of-plane component direction of wall is reversed being accompanied by the jump of the 

Neel cap positions. The probe Ms dependences of signal distortions such as contrast variation and distance 

change between the signal peaks which correspond to the measured wall width are also presented. 

[1] J. M. Garcia, et al., Appl. Phys. Lett. 79, 656 (2001). 

RP13 

Development of a non-conventional ESR spectrometer with a 

composite antenna system and an electronically controlled tuning and 

matching circuit 

Alexey Ponomaryov 1 , Kwang Yong Choi 2 , Byoungjin Suh 3 and Zeehoon Jang 4 * 

1 

Physics, Chungang University, Korea 

2 

Physics, Chungang, Korea 

3 

Physics, The Catholic University of Korea, Korea 

4 

Physics, Kookmin University, Korea 

We present a new development of non-conventional Electron Spin Resonance (ESR) spectrometer, in which the 

sweeping frequency is available in the wide range of frequency. This is a modification of the previous system 

without using a cavity and with two antennas one for the microwave transmission and the other for the ESR 

signal detection.[1] In contrast to previous work[1], utilization of microstrip antenna as a transmitter provided 

us the capability of wide-frequency operation between 0.8 and 10 GHz. On the other hand, the use of loop 

antenna as a detector with tuning and matching circuit enhanced ESR signal. In order to simplify tuning and 

matching circuit and make resonance condition easily reproducible, conventional capacitors were replaced with 

varactor diodes. This allowed us to avoid any mechanical action during tuning and matching procedure, since the 

capacitance of the diodes was changed by applying different DC voltages. Compared to Ref.[1], such a scheme 

increased S/N ratio several times in a wide frequency range. For testing the developed system, a homemade 

magnet with water-cooling system was used. The efficiency of the ESR spectrometer was checked by measuring 

a signal of 1,1-diphenil-2-picrylhydrazyl (DPPH) sample at different frequencies at room temperature. 

[1] Z. H. Jang, B. J. Suh, M. Corti, L. Cattaneo, D. Hajny, F. Borsa, and M. Luban, Rev. Sci. Instrum. 79, 46101 (2008). 

RP14 

RP15 

RP16 


A new type of spin-polarized scanning tunneling microscopy for 

observing an in-plane magnetization component with high resolution 

Daichi Nara 1 , Takuya Nakamura 1 , Atsuhiko Nakamoto 1 , Ryu Kageyama 1 , Elaiyaraju 

Srinivasan 2 , Kazuyuki Koike 1 and Hideo Matsuyama 1 * 

1 Department of Physics, Faculty of Science, Hokkaido University, Japan 

2 Creative Research Institution (CRIS), Hokkaido University, Japan 

To obtain a high resolution image routinely even from the rough surface of a ferromagnetic 

sample with a spin-polarized scanning tunneling microscope (SP-STM) operating in 

modulating tip magnetization mode [1], we have developed an SP-STM using a micrometersized 

magnetic tip integrated onto the magnetic recording head of a hard disk drive. The tip 

apex was formed into a round shape with a diameter of less than one micrometer by using a 

focused ion beam instrument. Driving the recording head with a signal generator to switch 

the magnetization of the tip apex periodically generates an unnecessary artificial current flow 

into a current-to-voltage (IV) converter through stray capacitance, which prevents detection 

of the spin-polarized tunneling current precisely. To reduce the artificial current, we added a 

homemade circuit that generates a countercurrent against the artificial current into the input 

of the IV converter. We tried to image both the topography and the spin polarization of an 

iron thin film deposited on a magnetic recording medium whose local roughness was on 

the order of several nanometers due to the crystal grains of the medium. This is the first spin 

image of a magnetic thin film having such a rough surface obtained with an SP-STM. 

[1] U. Schlickum, W. Wulfhekel, and J. Kirschner, Appl. Phys. Lett. 83, 2016 (2003). 

Violation of Hund's third rule in structurally disordered ferromagnets 

Vassilios Kapaklis 1 *, Panagiotis Korelis 1 , Bjorgvin Hjorvarsson 1 , Athanasios Vlachos 2 , 

Iossif Galanakis 3 , Panagiotis Poulopoulos 3 , K. Ozdogan 4 , Makis Angelakeris 5 , Fabrice 

Wilhelm 6 and Andrei Rogalev 6 

1 Department of Physics and Astronomy, Uppsala University, Sweden 

2 Department Materials Science, University of Patars, Greece 

3 Department Materials Science, University of Patras, Greece 

4 Department of Physics, Yildiz Technical University, Turkey 

5 Department of Physics, Aristotle University of Thessaloniki, Greece 


Violation of Hund's third rule caused by structural disorder is observed for the induced 

magnetic moment of Zr, using x-ray magnetic circular dichroism. The induced spin 

and orbital magnetic moments are antiparallel in the crystalline state, but parallel in 

an amorphous state of the investigated Co- and Fe-based materials. First-principles 

calculations are used to provide physical insight into the dependency of the spin-orbit 

coupling on the interatomic distance and coordination number. 

V. Kapaklis, P. T. Korelis, B. Hjorvarsson, A. Vlachos, I. Galanakis, P. Poulopoulos, K. Ozdogan, 

M. Angelakeris, F. Wilhelm, and A. Rogalev, Violation of Hund's third rule in structurally disordered 

ferromagnets, Phys. Rev. B 84, 024411 (2011). 

Bulk Cr tips with full spatial magnetic sensitivity for spin-polarized 

scanning tunneling microscopy 

Anika Schlenhoff, Andreas Sonntag*, Stefan Krause, Gabriela Herzog and Roland 

Wiesendanger 

University of Hamburg, Germany 

Spin-polarized scanning tunneling microscopy (SP-STM) is a powerful technique 

to access the magnetic properties of a surface on the atomic scale. Here, magnetic 

tips are usually prepared by extensive in-situ metal evaporation, demanding for a tip 

exchange mechanism inside the microscope. Using magnetic bulk tips is an elegant 

way to circumvent these efforts. For example, bulk chromium tips are reported to be 

suitable for SP-STM, exhibiting an in-plane magnetic sensitivity [1]. Since they are 

antiferromagnetic, their influence on the sample magnetization in terms of stray field 

interaction is negligible. We perform SP-STM experiments on the sample system 

of 1.8 atomic layers Fe/W(110) with the magnetization lying in the plane on the 

monolayer and pointing perpendicular to the plane on the double layer [2]. Our study 

demonstrates that Cr bulk tips can be used to image the complete magnetic structure 

and hence are sensitive to both the in-plane as well as the out-of-plane-component of 

sample magnetization [3]. Analyzing magnetic SP-STM maps enables the full spatial 

characterization of the tip. 

[1] A. L. Bassi et al., Appl. Phys. Lett. 91, 173120 (2007). [2] M. Pratzer et al., Phys. Rev. Lett. 87, 

127201 (2001). [3] A. Schlenhoff et al., Appl. Phys. Lett. 97, 083104 (2010). 


Poster Thursday


RP17 


Polarization state of scattered light in apertureless reflection-mode 

magneto-optical scanning near-field optical microscopy 

Yongfu Cai1, Mitsuharu Aoyagi 1 , Sanyalak Niratisairak 1 , Akira Emoto 2 , Tatsutoshi 

Shioda 3 and Takayuki Ishibashi 1 * 

1 

Department of materials science and technology, Nagaoka University of Technology, 

Japan 

2 

National institute of advanced industrial science and technology (AIST), Japan 

3 

Department of Electrical Engineering, Nagaoka University of Technology, Japan 

Magneto-optical scanning near-field optical microscopy (MO-SNOM) has attracted attention because of its 

high spatial resolution in magnetic imaging. We are developing a reflection-mode apertureless scanning nearfield 

optical microscopy (a-SNOM). The sample is a patterned Chromium film with a thickness of 20nm 

deposited on a glass substrate. The a-SNOM images are measured with Si tip that has an extremity’s radius 

of 7nm, and with an illumination of 408 nm with an incident angle of 45 degree. Scattered light caused by an 

interaction between the near-field wave and the sample was measured as a signal for a-SNOM image. Finitedifference 

time-domain (FDTD) method was used to calculate the polarization state of the scattered light. The 

a-SNOM images of Cr patterns were successfully obtained with a spatial resolution of 30-40nm. In addition, 

we found that the extinction ration of the scattered light back to the same direction with the incidence was 

better than 100, which is an enough polarization property for obtaining MO images. FDTD simulation 

reproduced that the scattered light preserved its polarization state. These results showed that the a-SNOM is a 

promising technique to obtain high-resolution magnetic images with a resolution of several tens nm. 

[1] E. Betzig, et. al., Appl. Phys. Lett. 61,142(1992). [2] Y. Mitsuoka, et. al., J. Appl. Phys. 83, 

3998(1998). [3] T. Yoshida, et. al., J. Magn. Soc. Jpn. 23,1960(1999). 

RP18 

Application of image processing to determine size distribution of 

magnetic nanoparticles 

Udomchok Phromsuwan 1 *, Yaowarat Sirisathitkul 2 , Chitnarong Sirisathitkul 1 and 

Bunyarit Uyyanonvara 3 

1 School of Science, Walailak University, Thailand 

2 School of Informatics, Walailak University, Thailand 

3 School of Information, Computer and Communication Technology (ICT), Sirindhorn 

<strong>International</strong> Institute of Technology (SIIT), Thammasat University., Thailand 

Digital image processing has increasingly been implemented in analyzing micro- and 

nanostructured materials and would be an ideal tool to characterize the morphology and 

position of self-assembled magnetic nanoparticles for high density recording. In this 

work, magnetic nanoparticles were synthesized by the modified polyol process using 

Fe(acac) 3 and Pt(acac) 2 as starting materials. Transmission electron microscopy (TEM) 

images of an as-synthesized product were taken with a resolution of 800 x 800 pixels, 

72 dot per inch and then inspected using image processing algorithms on MatLab. 

The grayscale image was converted to a binary image by using Otsu’s thresholding. 

An individual particle was then detected by using the closing algorithm with disk 

structuring elements and the canny edge detection. The areas of detected particles were 

filled and small objects were removed. A centroid, diameter and area of each particle 

were finally evaluated. The average diameter is 4.62 nm with a standard deviation of 

0.52 nm. The degree of polydispersity of magnetic nanoparticles can then be compared 

using size distribution from the image processing. 

RP19 

Microfabrication of a MEMS cantilever for mechanically detected 

high-frequency ESR measurement 

Eiji Ohmichi 1 *, Yoshimasa Yasufuku 2 and Hitoshi Ohta 3 




Mechanically detected high-frequency electron spin resonance (ESR) is a promising 

tool for high-resolution terahertz (THz) ESR spectroscopy of tiny magnetic samples. 

So far we succeeded in multi-frequency ESR detection for 80-370 GHz and achieved 

a spin sensitivity on the order of 10 9 spins/Gauss[1,2]. In this study, a prototype 

microcantilever is fabricated in order to further improve the sensitivity and flexibility 

of our ESR measurement system. Microcantilevers are fabricated from silicon-oninsulator 

(SOI) wafers using standard MEMS techniques such as lithography, wet 

etching, and RIE. By using commercial SOI wafers, fabrication cost and the number 

of process can be substantially reduced. Two types of cantilevers for capacitive 

and optical detection are fabricated in this study. The former has lateral dimensions 

of 4 mm x 8 mm, and is anodically bonded to a glass substrate to form capacitive 

electrodes. The latter has dimensions of 50 μm x 200 μm, and is equipped with a gold 

mirror for Fabry-Perot detection. Application to high-frequency ESR measurement is 

now in progress and details will be reported in the presentation. 

[1]E. Ohmichi, N. Mizuno, M. Kimata, and H. Ohta, Rev. Sci. Instrum. 79 (2008) 103903. [2]E. 

Ohmichi, N. Mizuno, S. Hirano, and H. Ohta, J. Low Temp. Phys. 159 (2010) 276. 


RP20 

2D reflection-type electron spin filter increasing the detection efficiency 

in spinresolved spectroscopy by 4 orders of magnitude 

D Kutnyakhov 1 , M Kolbe 1 , P Lushchyk 1 , M Jourdan 1 , K Medjanik 1 , S A Nepijko 1 , 

H J Elmers 1 , C Tusche 2 , J Kirschner 2 , F Giebels 3 , H Gollisch 3 , R Feder 3 and G 

Schoenhense 1 * 

1 Institute of Physics, University of Mainz, Germany 

2 Max Planck Institute of Microstructure Physics, Germany 

3 Theoretische Festkoerperphysik, Universitaet Duisburg-Essen, Germany 

Spin-resolved electron spectroscopy is characterized by a low figure of merit FoM= S²I/Io typically 10 -4 ; S 

spin sensitivity, I/Io reflectivity. Electron diffraction from W(001) in the (00) LEED spot facilitates parallel 

detection of 3800 data points in our imaging spin filter behind a PEEM [1], and 960 behind a hemispherical 

energy analyzer [2]. We achieved a “2D FoM” of 1.7 being four orders of magnitude higher than the previous 

value. We further studied the dependence of the spin sensitivity and reflectivity as a function of scattering 

energy and angle of incidence. The experimental setup includes a spin-polarized GaAs electron source, 

hemispherical analyzer and a Delaylinedetector. Intensities, spin-orbit-coupling induced asymmetries and FoM 

were calculated via a relativistic layer KKR SPLEED code [3]. The superior performance of multichannel spin 

detection facilitates experiments on highly reactive surfaces like in-situ prepared Heusler films [4] or radiationsensitive 

organic layers [5] and paves the way to single-shot experiments at ultra bright fs-sources like FELs. 

Funded by DFG (Scho341/9), Stiftung Innovation (project 886) and centre of complex materials COMATT. 

[1] C. Tusche et al., APL 99 (2011) 032505; [2] M. Kolbe et al., PRL 107 (2011) 207601; [3] R. 

Feder, Polarized Electrons in Surface Physics (World Scientific, Singapore, 1985); [4] M. Hahn et 

al., APL 98 (2011) 232503; [5] K. Medjanik et al., JACS 134 (2012) 4694 

RP21 

Element selective magnetization measurements under high magnetic 

field 

Andrei Rogalev* and Fabrice Wilhelm 

European Synchrotron Radiation Facility, France 

X-ray Magnetic Circular Dichroism (XMCD) spectroscopy is a well-established 

experimental tool to study the microscopic origin of magnetism allowing one to determine 

separately spin and orbital magnetic moments of each element in both amplitude and 

direction. So far, XMCD has been extensively used to investigate mainly ferro- or 

ferrimagnetic materials, and only very few studies have been performed on paramagnetic 

compounds. In this presentation we describe first a new experimental set-up dedicated to 

high field XMCD measurements that has been recently installed at the ESRF beamline 

ID12. Static magnetic field of up to 17 Tesla is generated by a superconducting solenoid. 

The sample is mounted on a cold finger of a He continuous flow cryostat allowing to 

set the temperature in the range from 2.2 K to 300 K with a stability of about 100 mK. 

Performances of this set-up are illustrated with results of element selective magnetization 

measurements in various systems: (i) Intrinsic magnetic moment in gold nanoparticles 

grown onto naturally thiol-containing proteinatious archaeal surface layer has been 

evidenced by field dependent XMCD at the Au L2,3-edges[1]; (ii) Extrinsic origin of 

room temperature ferromagnetism in diluted magnetic semiconductors has been proven 

with field and temperature dependent XMCD measurements[2]. 

[1] S. Selenska-Pobell et al., Nanomater. nanotechnol., 1 (2011), 8 [2] A. Ney et al., New J. Phys., 13 (2011) 103001 

RP22 

POLI: The new single crystal polarized neutron diffractometer for 

investigation complex magnetic structures at FRM-II 

Vladimir Hutanu*, Martin Meven, Gernot Heger and Georg Roth 

Institut fur Krystallographie, RWTH Aachen University, Germany 

POLI is a new single crystal polarized neutron diffractometer [1] at the hot source 

of the 'Forschungsneutronenquelle Heinz Maier-Leibnitz' (FRM-II) in Garching, 

Germany. It is designed to perform spherical neutron polarimetry (SNP) in zero field 

as well as classical polarized neutron diffraction (PND) measurements (flipping ratio) 

under applied magnetic fields. Among the intended applications of this instrument are: 

complex magnetic structures and magneto-electric coupling in multiferroics, magnetic 

structure and spatially resolved spin densities in molecular magnets, magnetically 

ordered superconductors, strongly correlated transition metal oxides and spin 

chain compounds. The instrument is unique in the sense that it combines a variable 

wavelength focussing monochromator with the use of 3He spin-filter cells (SFC) to 

create polarized, short wavelength neutrons. A new zero-field polarimeter Cryopad [2, 

3] has been built in cooperation between RWTH and ILL. On the detector side, the 

polarisation-analysis and detection unit DECPOL (again with 3He-spin filter cells) is 

used. This setup called 'POLI-HEIDI' is operational and open for users at FRM-II over 

JCNS proposal system. Its properties will be demonstrated in this talk. 

[1] V. Hutanu, M. Meven, E. Lelievre-Berna, G. Heger, Physica B 404, 2633 (2009). [2] F. Tasset, 

Physica B 156-157, 627 (1989). [3] E. Lelievre-Berna, “Novel polarized neutron tools”, I. Anderson 

& B. Guerard, Editors, Proceedings of SPIE 4785, 112-125 (2002).

RP23 

Observation of the magnetic domain using scanning electron 

microscopy with polarization analysis 

Sang Sun Lee, Moon Seob Bae, Wondong Kim and Chanyong Hwang* 


We have developed a scanning electron microscope with polarization analysis(SEMPA 

or spin-SEM) for the nano-scale observation of magnetic domain structure. A typical 

micro Mott type spin detector with 25 kV operating voltage, shows the effective 

Sherman function in the range between -0.3~-0.35, which is relatively low valued. In 

order to get higher Sherman function, we optimized all geometrical factors and the 

accelerating voltage. First, we tried Monte Carlo simulation by increasing operating 

voltage from 25 kV to 50 kV. At 40 kV of acceleration voltage with optimized 120 

degrees of scattering angle, a better effective Sherman function was obtained compared 

with the value operated at 25 kV(-0.5 : -0.3). Base on this simulation, we have 

developed the high-efficiency Mott spin detector with 40 kV operating voltage. Also 

a secondary electron deflector, and transfer lens system has been optimized. In order 

to test performance of the new spin detector, the thick Fe film sample was prepared on 

Si substrate using an evaporation method. We will show several different images of Fe 

films depending on the oxidation condition. 

RQ01 

Precision broadband ac measurement system for magnetotransport, 

magnetopolarization and magnetoelectric properties 

Jun Lu*, Baogen Shen and Xiaoping Shao 

State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of 


For complex or strongly correlated magnetic materials, broadband ac measurements 

provide much richer dynamic information than static or quasistatic measurements, 

which would help one to understand more clearly how magnetic materials of interest 

respond to various external excitations. After many-year researches, we have developed 

a suite of precision broadband ac magnetic measurement system based on novel 

broadband digital lock-in amplifier techniques, which can work from sub 1 Hz to above 

1 GHz. In addition to multi-channel lock-in amplifier techniques, to realize broadband 

ac transporting and polarizability measurement from sub 1 Hz to above 100 MHz, 

transmission-line bridge compensation techniques have been used so as to measure 

complex ac magnetoresistance and Hall coefficient simultaneously in a precision way. 

Broadband ac magnetoelectric measurement system has also been set up for evaluating 

complex magnetoelectric coupling coefficient, which including not only magnitude but 

also phase lag. For various magnetotransport and magnetoelectric measurements, we 

have developed measuring software which supports fully automatic tests. 

[1] J. Lu et al., Meas. Sci. Technol., 19, 045702-6(2008) [2] J. Lu et al., IEEE Trans. Magn., 44(9), 

2127-9(2008) [3] J. Lu et al., A kind of precision broadband anti-noise lock-in frequencymeter, 

Chinese Patent, 201110380805.X 

RQ02 

Detection of magnetic beads using an extraordinary magnetoresistance 

sensor fabricated with unpatterned semiconductor substrate 

Jian Sun* and Jurgen Kosel 


A strong geometry dependent magnetoresistance effect, the so-called extraordinary 

magnetoresistance (EMR), has been observed in semiconductor/metal hybrid 

structures. It is based on the redistribution of the current from the metal shunt into 

the semiconductor causes by the Lorentz force. A typical EMR device consists of a 

patterned semiconductor mesa and metal shunt. When the dimensions of the device 

are reduced, for example, to increase the sensitivity, the alignment of the metal contact 

with the semiconductor bar becomes more difficult. Furthermore, the patterning 

process inescapably causes some damage to the semiconductor thereby reducing the 

performance. In this work, we report a new EMR device fabrication process, which 

does not require patterning of the semiconductor substrate reducing the complexity of 

the fabrication and omitting any kind of damage of the semiconductor. The sensitivity 

of this device is 0.58 μT/√Hz, which is twice as high as the one of the patterned sensor. 

The device is employed to detect superparamagnetic beads of 2.8 μm in diameter, 

which is the first time this is demonstrated with an EMR sensor. Applying the beads to 

the sensor surface results in a voltage signal of 100 μV. 

RQ03 

RQ04 

RQ05 

Ac Calorimetry under Pulsed High Magnetic Field 

Yuji Inagaki 1 , Tatsuya Kawar 1 , Akira Matsuo 2 and Koichi Kindo 2 

1 applied quantum physics, kyushu university, Japan 

2 institute for solid state physics, the university of tokyo, Japan 


Magnetization of single ferromagnetic-grain obtained from 

observation of field-induced-translation in a chamber-type μg system. 

Chiaki Uyeda 1 , Kenta Kuwada 2 and Keiji Hisayoshi 2 

1 Graduate School of Science, Osaka university, Japan 

2 Graduate school of Science, Osaka university, Japan 

A new principle to measure saturated magnetization Ms of a single ferromagnetic-grain 

is proposed, which is based on free translation of the grain caused by field-gradient force. 

The motions were observed in a diffused (~10Pa) μG condition (0.01G). It is confirmed 

for the first time that a classical conservation rule between field-induced potential and 

kinetic energy is conserved for a translating magnetic-grain. Accordingly, Ms is obtained 

from the relationship between sample velocity and field intensity observed at different 

sample positions. The Ms value is obtained even for a nano-sized sample, provided that 

translation is observed by an ultra-violet fluorescence microscope [1]. This is because the 

method does not require mass measurement; it is also free of the interfering signal emitted 

from a sample holder [1]. The above two factors has been the major problem in detecting 

magnetization of single grain in conventional methods. A chamber-type drop shaft to 

produce μG, which can be introduced in an ordinary laboratory, was newly developed 

to realize routine Ms measurement. Here, size of drop capsule was reduced to 30cm in 

diameter by introducing a magnetic circuit composed of an NdFeB permanent magnet. 

[1] C.Uyeda et al: Jpn. Phys. Soc. Jpn. 79, 064709 (2010). 

application of magnetoimpedance effect for protein biomarker 

detection 

D.g. Park and Hoon Song 


Ultra-low concentration detecting of biomolecules, has gain increasing interest since 

various protein biomarkers for cancer or chronic diseases are present at very low levels 

at the early stages of the disease development [1].In this work, we present the results of 

the development of a sensor prototype working in a principle of label free for monitoring 

the effects on the immobilization of the biomolecular using giant magnetoimpedance. 

Amorphous ribbons were tested in different biomoleculars. The MI response of the 

sensive elements made from ribbons was measured with a various biomolecular in 

order to demonstrate the capacity of monitoring the immobilization of biomolecule. To 

demonstrate the sensitivity and specificity of this GMI sensor platform for biomolecule 

detection and quantification, we have used this platform to successfully detect and 

quantify the biomolecules. To apply to the real biomarker and verify the sensitivity of 

GMI-based magnetic sensor, we used the biomarker scheme using the applied the real 

protein on the magnetic sensor surface. The capture antibodies (P21 mono antibody) 

are first immobilized on the positive magnetic sensor surfaces. The advantage of this 

approach consists in the possibility to design a biosensor with enhanced sensitivity and 

the application for detection of small amounts of biomolecules. 

[1] M. Gomez and G. Silvestri, “Lung cancer screening,” Am. J. Med. Sci., vol. 335, pp. 46-50, 

2008 

Ac calorimetry measurement adapted for use of the pulsed high magnetic field will be 

presented. This technique is quite useful to investigate the thermal properties under 

high magnetic field beyond the steady magnetic field range. In addition, it is also 

possible to capture a transient phenomena under fast sweep magnetic field. Resultant 

examples will be presented in detail. 


Poster Thursday



RQ06 

Specific heat and thermal expansion of Sr 1-xCa xRuO 3 

Rasna Thakur 1 *, Archana Srivastava 2 , Rajesh K. Thakur 1 and N.k. Gaur 1 

1 Department of Physics, Barkatullah University, Bhopal, India 

2 Department of Physics, Sri Satya Sai College for Women, Bhopal, India 

We have investigated the thermodynamic properties of perovskite ruthnate Sr 1xCa 

xRuO 3 (0≤ x ≤1) probably for the first time by means of Rigid Ion Model (RIM). 

The lattice contributions to the specific heat and thermal expansion of pure and Ca 

doped SrRuO 3 as a function of temperature (0 K≤ T ≤ 1000 K) are reported. The 

systematic trend of variation of specific heat and the closer agreement with the 

experimental data reveal the suitability and appropriateness of RIM, for Sr 1-xCa xRuO 3 

(0≤ x ≤1) perovskite ruthnates. The calculated lattice specific heat gives Debye 

temperature (478.4 K) which is consistent with experimental value (480 K). Our 

calculated value of 494.4 K for CaRuO 3 is in very good agreement with the reported 

value of 495 K. The Atoms in Molecules (AIM) theory is used to determine the bulk 

modulus of these compounds. Further, the value of Gruneisen parameter is calculated 

which is within the range 2-3 as reported earlier for perovskite family. In addition, the 

results on cohesive energy (φ), molecular force constant (f), restsrahlen frequency (υ), 

Debye temperature(θ D) and gruneisen parameter (γ) are also presented. Our results 

on cohesive and thermal properties revealed by using RIM reproduces well with the 

available experimental data. 

RQ07 

Voltage-current characteristics of superconductor-normal metal 

contact junctions measured by a picovoltmeter 

Wan-seop Kim*, Mun-seog Kim, Po Gyu Park, Kyu-tae Kim and Danbee Kim 

KRISS, Korea 

A picovoltmeter based on a DC SQUID has been developed for improvement of 

Josephson voltage measurement uncertainty to better than ΔV/V = 50 x 10-12. An 

output to input ratio of 108 is achieved using a proper current feed-back system. 

The performance of the picovoltmeter demonstrated by the Voltage(V)-Current(I) 

measurements on a Cu-wire with a diameter of 0.25 mm and a length of 10 mm shows 

that a voltage resolution is of about 10-12 V (pV) and a corresponding resistance 

resolution is order of 10 μΩ. In addition, the current sensitivity of the picovoltmeter 

was found to be 2x10-7 A/Φ0, where Φ0 is the magnetic flux quantum. Here we 

present voltage steps induced by magnetic flux trap in the V-I curve measurements 

for a bulk cylinder-type Pb wire with a diameter of 0.25 mm. The step height was 

observed to change abruptly in an irregular manner, but in multiple of 6 pV. Moreover, 

dissipation behavior of the remnant voltage observed in the V-I curves for thick films 

of superconductor/normal metal/superconductor contact junctions will be discussed. 

RQ08 

Development of high resolution cryogenic particle detectors using a 

magnetic calorimeter 

W.S. Yoon 1,2 , Y.S. Jang 1 , S.J. Lee 1 , G.B. Kim 1 , H.J. Lee 1,2 , K.B. Lee 1 , M.K. Lee 1 , Y.N. 

Yuryev 1 , Y.H. Kim 1,2 

1 Korea Research Institute of Standards and Science 

2 University of Science and Technology 

Micro-calorimeters operating at low temperatures have become important tools in 

many aspects of science because of their high energy resolution much beyond the limit 

of semiconductor based detectors. These sensitive detectors measure the temperature 

dependent properties of sensor materials such as their resistance or magnetization. 

In metallic magnetic calorimeters, a small concentration of erbium doped in gold 

host provides a paramagnetic system, in which the magnetization is inversely 

proportional to the temperature. A metallic film of the sensor material is fabricated on 

a superconducting meander-type pickup coil connected to an input coil of a SQUID 

current sensor. An absorber, another gold foil, is employed to detect incident alpha 

particles. The gold foil absorber and the magnetic temperature sensor are thermally 

connected by gold bonding wires. The kinetic energy of each particle is converted into 

a temperature increase of the absorber/sensor assembly. In the present report, the recent 

progress on high resolution alpha spectrometers using these detectors is discussed 

together with an application to radionuclide analysis. 


RQ09 

High pressure inductive measurements using microcoils in anvil cells. 

Swee K. Goh 1 *, Thomas Meissner 2 , Patricia Alireza 1 and Juergen Haase 2 

1 University of Cambridge, United Kingdom 

2 University of Leipzig, Germany 

Diamond or Moissanite anvil cells are routinely employed to reach pressures higher 

than 35 kbar. However, due to the presence of the gasket and the limited sample space, 

inductive type measurements have been challenging. To overcome these challenges, 

we place a microcoil inside the gasket hole of the anvil cell. With an increase in the 

filling factor and the close proximity between the sample and the coil, this arrangement 

has so far enabled us to perform AC susceptibility [1], the de Haas-van Alphen effect 

[2], tunnel-diode oscillator [3] and Nuclear Magnetic Resonance [4,5] experiments. 

Technical aspects associated with the preparation of these pressure cells will be 

presented, with particular emphasis placed on recent NMR experiments performed 

using this technique. 

[1] P. L. Alireza et al., Rev. Sci. Instrum. 74, 4728 (2003) [2] S. K. Goh et al., Curr. Appl. Phys. 8, 

304 (2008) [3] S. K. Goh et al., arXiv:1107.0689 (2011) [4] J. Haase, S. K. Goh et al., Rev. Sci. 

Instrum. 80, 073905 (2009) [5] T. Meissner, S. K. Goh et al., Phys. Rev. B 83, 220517(R) (2011) 

RQ10 

Microwave synthesis and characterization of the series of co 4-xfexsb 12 

high temperature thermoelectric materials 

Alexandra Ioannidou 1 *, Margarit Gjoka 2 , Dimitris G Niarchos 2 , A Borrell 3 , M D 

Salvador 4 and F L Penaranda-foix 5 

1 Institute of Materials Science, NCSR Demokritos, Athens, Greece 


3 Instituto de Tecnologia de Materiales (ITM), Universidad Politecnica de Valencia, Camino de Vera,, Spain 

4 Instituto de Tecnologia de Materiales (ITM), Universidad Politecnica de Valencia, Camino de Vera, s/n, 

46022 Valencia, Spain 

5 Instituto de Aplicaciones de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas, 

Universidad Politecnica de Valencia, Camino de Vera, s/n, 46022 Valencia, Spain 

An alternative route has been followed for a rapid synthesis of skutterudites as it was suggested by Biswas et 

al. (1) using microwave assisted synthesis. Microwave heating and sintering (involve microwaves only at 2.45 

GHz and 915 MHz frequencies) is fundamentally different from the conventional sintering, which involves 

radiant/resistance heating followed by transfer of thermal energy via conduction to the inside of the body being 

processed. Microwave heating is a volumetric heating involving conversion of electromagnetic energy into 

thermal energy, which is instantaneous, rapid and highly efficient. The use of microwave energy for materials 

processing has major potential and real advantages over conventional heating. These include: - Time and 

energy savings. - Rapid heating rates (volumetric heating vs. conduction). - Considerably reduced processing 

time and temperature. - Fine microstructures - Lower environmental impact. Using the microwave-assisted 

synthesis, here we report our effort to synthesize the series of Co4-xFexSb12 using this novel approach, 

which gave high quality materials with little or no impurity in a fraction of time compared to the conventional 

synthesis. We will present data for structural, microstructural and thermoelectric properties and compare with 

materials synthesized with conventional approach. Supported by the project NEXTEC of the EU 

1. K. Biswas, et al. MRS Bulletin 46, pp. 2288-2290 (2011). 2288-229 2. R. Roy, et al. Nature 399, pp. 668-670 (1999). 

RQ11 

Development of SI-STM optimized for 3D(x,T,B) phase-diagram-wide 

FTSTS mapping on high Tc superconductors 

Seokhwan Choi 1 , Jimin Kim 1 , Chanhee Kim 1 , Jaewook Kim 1 , Hwansoo Suh 2 and 

Jhinhwan Lee 1 * 

1 Physics, KAIST, Korea 

2 FRL, SAIT, Korea 

We are constructing an SI-STM optimized for 3D(x,T,B) phase-diagram-wide QPI 

mapping on high Tc superconductors, Kondo systems and SCESs. It is based on Panstyle 

STM design for high magnetic field compatibility and yet has enough symmetry 

required for covering a wide temperature range with minimal drift. Also it has multiple 

sample storage at 4K for unlimited reuse of samples with various dopings. Its primary 

goal is to extend the SI-STM measurement coverage over the most significant regime 

of the 3D phase diagram for unique determination of the mechanisms of high Tc 

superconductivity using the fully-phased Green-function-based cross-sectional FTSTS 

analysis method.

RQ12 

Homemade microcalorimetry equipment, with magnetic fields up to 9 

Teslas, for magnetocaloric measurements 

J. V. Leitao*, P. Van Dommelen, F. Naastepad and E. Bruck 

Delft University of Technology, Netherlands 

The magnetocaloric effect (MCE) has gains relevance as a cheap and environmentally 

friendly alternative to the current household vapor cycle refrigerators. The most 

common method for calculating the MCE of a material, due to its technical and 

mathematical practicality, is the application of Maxwell’s thermodynamic equation 

to a set of magnetic isotherms so as to calculate the magnetic entropy change [1]. 

The other current alternative for this calculation is through the adiabatic temperature 

change. Unfortunately, even though a working magnetocaloric refrigerator should rely 

much more on an adiabatic (Brayton) cycle [2], such calculation is usually hindered 

by the lack of a proper measurement system that would allow for reliable specific heat 

measurements with an applied magnetic field. Our group has recently constructed 

such a device, using a 9 Tesla cryostat, allowing for liquid helium temperatures, and 

microcalorimetry chips from the company Xensor Integration. This equipment, besides 

the usefulness in magnetocalorics research, is an invaluable tool in the study and 

investigation of any form of phase transitions where the application of a magnetic field 

may play a significant role. We now report the overall characteristics of this equipment 

and further illustrate it with a few early measurements performed on it. 

[1]Debye P, 1926, Some observations on magnetisation at a low temperature, Ann. Phys. 81: 1154-1160; [2] 

Tishin A.M, Spichkin Y.I, 2003, The Magnetocaloric Effect and its Applications, MPG Books Ltd., Bodmin, 2003; 

RQ13 

Nucleation and development of clustered state in hole doped 

manganites and cobaltites 

A. V. Lazuta 1 , V. A. Ryzhov 1 , V. P. Khavronin 1 , P. L. Molkanov 1 and Ya. M. 

Mukovskii 2 

1 Petersburg Nuclear Physics Institute, Gatchina, St.Petersburg 188300, Russia 

2 Moscow Steel and Alloys Institute, Leninskii prosp. 4, Moscow 117936, Russia 

The origination of the ferromagnetic (F) metallic (M) clusters in a paramagnetic (P) state of the hole 

doped manganites was well established [1-3]. Study of this state in the hole doped cobaltites is the 

topic of the current research activity [4,5]. It is found by measurements of the nonlinear magnetic 

responses (the second and third orders) that an universality exists in the nucleation and development of 

the clustered states (CS) in these systems which proceed into three stages. On cooling, during the first 

stage, the F clusters nucleate at the preferential sites that are likely produced by variation in oxygen and 

doping stoichiometry. Second stage is characterized by a sharp increasing concentration of the isolated 

F clusters. A coalescence of the clusters into large-scale complexes containing some amount of the F 

domains is associated with the third stage that can end with formation of a percolative FM network. 

This scenario is demonstrated by using the data obtained on the single-crystalline manganites Pr1-x 

CaxMnO 3 (x = 0.2, 0.25; the F insulators) and single-crystalline cobaltite La 0.7Sr 0.3CoO 3 (a F metal). A 

new effect is found in the latter, in which the CS in the P metallic regime is observed for the first time. 

[1] M. B. Salamon, M. Jaime, Rev. Mod. Phys.73 (2001) 583. [2] V.A. Ryzhov, A.V. Lazuta, I.D. Luzyanin 

et al., Zh. Eksp. Teor. Fiz. 121 (2002) 678. [3] A.V. Lazuta, V.A. Ryzhov, V. P. Khavronin et al., Funct. 

Mater. 17 (2010) 11 and Ref. therein. [4] C. He, S. El-Khatib, S. Eisenberg et. al., Appl. Phys. Lett. 95 (2009) 

222511. [5] A. V. Lazuta, V.A. Ryzhov, A. I. Kurbakov et al., Solid State Phenom. 168-169 (2011) 457. 

RQ14 

Measurements and analysis of core loss including higher harmonic 

induction waveforms using superposition principle and steinmetz’s law 

Duhyung Yeon and Derac Son* 

Physics, Hannam university, Korea 

Non-oriented electrical steels have been used in rotating electric machines. Magnetic 

induction waveforms of stator cores of induction motors have ac major hysteresis 

loop of driving frequency and ac minor loops due to the slip. Prediction of core loss 

including higher harmonic is one of important task for high efficiency induction 

motor design[1]. In this work, we have constructed core loss measuring system which 

could control waveform of magnetic induction the same as generated from waveform 

synthesizer using analog negative feed-back system and test specimen was used air 

flux compensated ring core. Using the developed measuring system, we can measured 

core losses of ac minor loops which depend on the peak amplitude and position 

in major hysteresis loop and theses core losses obeyed Steinmetz’s law. Core loss 

including minor loops could be calculated superposition principle of the core loss from 

major hysteresis loop and the core losses from minor loops which come from higher 

harmonic induction. 

[1] D. Son “AC hysteresis loop measurement of stator-tooth in induction motor”, IEEE Trans. on 

Magn., Vol.35, No.5, p.3931~3933(1999) 

RQ15 

RQ16 

RQ17 


Highly sensitive cantilever magnetometryin static and dynamic modes 

for micro-scale samples 

Heonhwa Choi 1 , Yun Won Kim 2 and Jae-hyuk Choi 1 * 

1 

Nano Science, University of Science and Technology ; Divison of Physical metrology, 

KRISS, Deajeon 305-340, Korea 

2 

Display and Semiconductor Physics, Korea University, Chungnam 339-800 ; 

Divison of Physical metrology, KRISS, Deajeon 305-340, Korea 

Recently, dynamic modecantilever magnetometriesusing an ultra-soft cantilever with 

attonewton dynamic force sensitivity arebecoming a very powerfultool for measuring 

the magnetic properties of micrometer-sized samples. In spite of its high sensitivity, the 

dynamic mode measuring a cantilever’s resonance frequency shifthas a limitation that 

it requires anisotropic magnetic samples,andhigh or moderate external magnetic fields. 

Therefore, we suggest a new type of a cantilever magnetometry with no limitation on 

magnetic anisotropy and external magnetic field, a cantilever forcemagnetometrywhich 

measuresastatic displacement of a cantilever in a well-defined magnetic field gradient. 

Its principle and experimental details including the magnetometry’sstructure are 

presented, which are accompanied by the results of measurement at T = 3.5 K on a 

small magnetic moment of 1.84 x 10-14 A m 2 using both static and dynamic modes 

revealing the high sensitivity of the static mode. 

Pulsed high magnetic fields for synchrotron and neutron applications 

Fabienne Duc*, Xavier Fabreges, Paul Frings, Marc Nardone, Julien Billette, Jerome 

Beard, Abdelaziz Zitouni and Geert Rikken 

Laboratoire National des Champs Magnetiques Intenses - CNRS Grenoble-Toulouse, 

France 

As is well known, a magnetic field, together with temperature and pressure, is a very 

important and efficient thermodynamic parameter for the investigation of condensed 

matter. It can be used as an external variable to tune the ground and excited states 

properties of a given magnetic system. The last ten years have seen a growing interest 

for the combined use of pulsed high magnetic fields (up to 40 T) at synchrotron and 

neutron sources. Because of the larger flux of synchrotron x-ray sources compared 

to neutron facilities, the development efforts have been first focused on synchrotron 

methods. Neutron diffraction has complementary features to x-ray diffraction, and 

unique capabilities for studying microscopically the magnetic properties of materials. 

Here, we will present the various devices developed by the LNCMI, Toulouse to 

combine pulsed high magnetic fields with synchrotron and neutron techniques. These 

developments are performed in close collaboration with the ESRF, Grenoble for 

synchrotron applications and with the ILL and CEA, Grenoble for neutron diffraction. 

We will discuss the main limitations for the use of pulsed magnetic fields related to 

their low duty cycle. Those instrumental developments will be illustrated by some 

recent results. 

Characteristics of an SQUID system with a superconductive shield for 

biomagnetic measurements 

Kwon Kyu Yu, Kiwoong Kim, Hyuckchan Kwon, Jin Mok Kim and Yong Ho Lee 

Brain and Cognition Measurement Lab, KRISS(Korea Research Institute of Standards 

and Science), Korea 

We have fabricated a magnetoencephalography (MEG) system having a 

superconductive shield helmet. By using the perfect diamagnetic effect of the 

superconductor (Pb), superconducting quantum interference device (SQUID) 

magnetometers inside the Pb enclosure can be shielded from external magnetic 

disturbances, and this effect can be used to enhance the signal quality of biomagnetic 

signals. Along the surface of the helmet, the shielding factor (SF) was from 28 to 57 

dB, depending on the position of the SQUID from the edge. SF reduced rapidly as 

the distance from Pb surface increased. The shielded helmet-shape MEG system has 

a noise level of about 7 fT/Hz1/2 at 1 Hz, and 3 fT/Hz1/2 at 100 Hz. Auditory evoked 

brain signals were measured and were compared in the case of superconductive shield 

and without shield, and confirmed big improvement of the signal quality by using 

superconductive shield. 

[1] Y. H. Lee, “A low noise multichannel magnetocardiogram system for the diagnosis of heart electric activity”, Korean society of 

medical and biological Eng., Vol. 27, pp. 154-163, 2006. [2] R. H. Kraus, “ First Results for a Superconducting Imaging-Surface 

Sensor Array for Magnetocardiography”, Recent Advances in Biomagentism Proceeding, pp. 43-46, 1999. [3] D. B. Hulsteyn, “ 

Superconducting Imaging Surface Magnetometery”, Rev. Sci. Instrum., Vol. 66, pp. 3777-3784. [4] H. Ohta,“A 64-channel whole 

head SQUID system in a superconducting magnetic shield”, Supercon. Sci. Technol., Vol.12, pp. 762-765, 1999. 


Poster Thursday



RQ18 

Radio-frequency atomic magnetometer for sensitive susceptibility 

detection 

Hyun Joon Lee 1 , Han Seb Moon 1 , Yong-ho Lee 2 , Seong-joo Lee 2 , Kwon-kyo Yu 2 and 

Kiwoong Kim 2 * 

1 Pusan National University, Korea 

2 Korea Research Institute of Standards and Science (KRISS), Korea 

Alkali-metal magnetometers use the coherence precession of polarized atomic spins to detect and 

measure magnetic fields. Previously, the interaction between light and atoms allows magnetometers 

to detect and measure magnetic fields, with sensitivity of 10 fT/√Hz [1]. Atomic magnetometers 

such as spin-exchange relaxation free (SERF) regime magnetometer and coherence population 

trapping (CPT) magnetometer have been designed to detect of varying magnetic fields mainly at low 

frequency. Therefore, detection of weak fields at high frequencies up to several megahertz requires an 

alternative detection method. To observe the Nuclear magnetic resonance (NMR) signals at several 

tens of kilohertz, RF (Radio-Frequency) atomic magnetometer can be used. RF magnetometer has a 

fundamental sensitivity limit on the order of 0.01 fT/√Hz [2, 3]. In RF magnetometer, the oscillating 

magnetic field causes the polarization of each spin to rotate along the pumping axis, with the transverse 

spin component increasing until the polarization is perpendicular to the pump axis. The resonant RF field 

eventually makes all of the processing spins coherent. In this study, the measured SNR corresponded to 

a sensitivity of 50 fT/√Hz at 25 kHz and such results will be useful to atomic NMR detector. 

[1] J. C. Allred, R.N. Lyman, T.W. Kornack and M.V. Romalis, Phys. Rev. Lett. 89, 130801 (2002) [2] 

S.-K. Lee, K. L. Sauer, S. J. Seltzer, O. Alem, and M. V. Romalis, Appl. Phys. Lett. 89, 214106 (2006) [3] 

I.M. Savukov, S.J. Seltzer and M.V. Romalis, Journal of Magnetic Resonance 185 (2007) 214-220 

RQ19 

Cancellation coil allows precision magnetic measurements with strong 

magnetization field inside a shielded enviroment 

Seong-min Hwang, Kiwoong Kim*, Chan Seok Kang, Seong-joo Lee and Yong-ho Lee 

Brain and Cognition Measurement Lab., Korea Research Institute of Standards and 


A great number of precision magnetic measurements can benefit significantly from, or in some 

cases, even require strong prepolarization fields (B p) and magnetically shielded environments. 

We devised a cancellation coil (CC) to neutralize the B p on electrically conductive shield walls 

that may otherwise induce currents on the walls to produce a lingering transient residual field (B tr) 

inside the shielded environment and disrupt the measurement operations. The CC was designed 

using the inverse problem method to effectively neutralize magnetic fields generated on the 

shield walls by the B p coil. The implemented CC was evaluated by measuring the resulting B tr 

after strong pulsed B p using a fluxgate magnetometer at different magnetometer positions and 

cancellation coil currents (ICC). We have conducted multi-mode component analysis on the 

B tr measurements to reveal two dominant components, where the component with shorter time 

constant comes from the current induced around the shield side walls and the other with longer 

time constant from the current induced on the ceiling and floor of the MSR. The analysis also 

allows optimization of ICC for each of the top, side, and bottom sections of the CC to enable 

significantly easier fine-tuning of individual sections of the CC to enhance CC performance. 

Seong-min Hwang, Kiwoong Kim, Chan Seok Kang, Seong-Joo Lee, and Yong-Ho Lee, Appl. Phys. Lett. 99, 132506 (2011) 

Seong-min Hwang, Kiwoong Kim, Chan Seok Kang, Seong-Joo Lee, and Yong-Ho Lee, submitted to J. Appl. Phys. 111, 

083916 (2012) 

RQ20 

Development of a SQUID based ultra-low-field MRI system 

Seong-joo Lee, Kiwoong Kim*, Chan Seok Kang, Seong-min Hwang and Yong-ho 

Lee 

Brain and Cognition Measurement Lab., Korea Research Institute of Standards and 


We obtained 2-dimensional Magnetic Resonance Imaging (MRI) image of a phantom 

in fields of a few microtesla by using a dc Superconducting QUantum Interference 

Device (SQUID) based MRI system. Microtesla MRI technique is a challenging 

application based on SQUID technology. The high sensitivity of the SQUID 

magnetometer enables measurement of very weak magnetic resonance signals even 

for the low Larmor frequency in microtesla fields. Measuring the nuclear magnetic 

resonance (NMR) signals at such a low field gives many benefits like development of 

an open-type low-cost surgery-monitoring MRI system, high-contrast cancer detector, 

etc. In this presentation, we introduce experimental details for ultra-low-field (ULF) 

MRI. 


RQ21 

26 T+ steady magnetic field for neutron science at HZB Berlin 

P. Smeibidl, Karel Prokes*, H. Ehmler, O. Prokhnenko and A. Tennant 

M-I1, Helmholtz Zentrum Berlin, Germany 

The Helmholtz Zentrum Berlin is building in collaboration with the National High 

Magnetic Field Laboratory, Tallahassee, FL, USA a new series-connected hybrid 

magnet system for neutron scattering experiments [1]. Two conical endings of 30° 

opening angle enable neutrons to hit the sample and to be detected either in the forward 

or backward direction. To achieve a maximum field with the present technology, a 

13 T superconducting Nb 3Sn cable-in-conduit coil is combined with resistive insert 

coils of 13 T to 19 T, depending on electric power, to give a maximum of 26 to 32 

T. The magnet that provides a 50 mm diameter room temperature bore in horizontal 

orientation will be permanently mounted at the dedicated time-of-flight instrument 

ExED 76 m away from the neutron source. The contribution describes the most 

important design features of the system (the 20 kA, 8 MW power supply, the helium 

refrigerator system for cooling of the superconducting coil and the 4-8 MW water 

cooling system for cooling of the resistive coil), the status of the fabrication of the 

components, the outline of the building for the technical infrastructure and the status of 

the installation of the most important components. 

[1] P. Smeibidl et al., J. Low Temp. Phys. 159, 402 (2010). 

RQ22 

A simple method for measuring blocking temperatures 

Mansor Hashim 1 , Ghazaleh Bahmanrokh 2 and Ismayadi Ismail 1 

1 Institute of Advanced Technology, Universiti Putra Malaysia, Malaysia 

2 Physics Department, Faculty of Science, Universiti Putra Malaysia, Malaysia 

We describe a new method for measuring a blocking temperature, much simpler than 

that involving a SQUID. Nanoparticles of Co, Co coated with Au,Co-Pt and Co-Pt 

coated with Au were prepared by the reverse micelle microemulsion method. The 

four magnetic powder specimens were each pressed to yield a disc. A Hall-effect 

probe blade surface was stuck intimately against one flat surface of the disc. Properly 

analysed, this arrangement allows the probe to detect the normal component, BN, 

projecting from the disc since, at the interface, BN (air) = BN (disc). Use of this 

relation led to the determination of a magnetic moment near the disc surface. By 

simply cooling this arrangement of disc + probe in a probe station to 15K, a graph of 

the magnetic moment was clearly peaked at a temperature which, unmistakably, was 

the blocking temperature, TB. For the four different samples TB lies between 40K and 

45K. 

RQ23 

Optimization of operation condition of orthogonal fluxgate sensor 

fabricated with Co based amorphous wire 

Yongmin Kim 1 , Young-hak Kim 2 , Sang-ho Lim 3 , Cang-seob Yang 4 and Kwang-ho 

Shin 1 * 


Korea 



4 Agency forDefense Development, Korea 

Orthogonal fluxgate (OFG) sensors have an additional advantage comparing with conventional fluxgate sensors 

in their simple structure [1-2]. Because the sensitivity of an OFG is typically proportional to its winding number N, 

cross section area of its magnetic core A, and operation frequency f, the f should be as high as possible to prevent 

reduction of the sensitivity in the case of small-sized OFG sensors in which the N and A are restricted. The f is 

limited due to the LC resonance occurred by inductance and stray-field capacitance of the pickup coil around the 

magnetic core and transmission line, coaxial line in this study, as well as performance of the signal conditioning 

circuit in common. And the sensitivity could be also reduced according to increase of operation frequency due 

to the skin effect if the sensor is operated in the frequency range of near MHz. We present how to optimize 

the operation condition including frequency of the OFG fabricated with a CoFeSiB amorphous wire with the 

diameter of 100 μm in this paper. The LC resonance frequency according to external capacitances was calculated 

with an equivalent circuit and FEM analysis to calculate the magnetization distribution in a high frequency. 

[1] E. Paperno, E. Weiss and A. Plotkin, IEEE Trans. Magn., 44, 4018 (2008). [2] I. Sasada, J. Appl. Phys., 91, 7789 (2002).

RR01 

Preparation of γ-Fe4N and ε-Fe3N particles with high magnetization 

for electromagnetic wave absorption applications 

Ming-fong Tai 1 *, Hsin-tzu Liu 2 , C. M. Lin 3 and Huan-chiu Ku 1 


2 Department of Chemical Engineer, National Tsing Hua University, Taiwan 

3 Department of Applied Science, National Hsingchu University of Education, Taiwan 

High-Ms ferromagnetic iron nitrides have vast applications on microwave absorbing 

and magnetic recording. In this study, we successfully used a simple nitrogen 

treatment to prepare cubic γ-Fe 4N and hexagonal ε-Fe 3N powder. Both kinds of 

powders are synthesized by the nitriding process of the commercial micro-scale Fe 

and Fe 2O 3 powders, at 550°C for 5 hours during a flowing mixture of NH 3 and H 2 

gas. Our pure γ-Fe 4N powder exhibits a high saturation magnetization of 15.03 kG at 

room temperature, which is slightly lower than that of bulk Fe (22.0 kG @ 4 K) but is 

considerably higher than that of γ-Fe 2O 3 (4.0 kG @ 4 K). The ε-Fe 3N powder including 

a slight amount of γ-Fe 4N was also synthesized by heating the commercial Fe 2O 3 

powder with the same procedure. The chemical stabilities of both γ-Fe 4N and ε-Fe3N 

powder are superior to that of the pure Fe and have high level of mechanical hardness. 

The mircostructures and electron spin resonances of our iron nitrides were also studied. 

This work was supported by the National Science Council, Taiwan under the NSC 98-2112-M-007- 

016-MY3 project. 

RR02 

Methods for determining the quality of magnetic fluids 

Viorica Chioran 

University Babes-Bolyai - Cluj Napoca / Romania, Romania 

The conversion parameter of the magnetic properties of magnetic fluids is a physical 

quantity describing the quality of those fluids from a technological point of view. 

This study determines the value of this parameter for three samples of magnetic 

fluid. Many technical applications require magnetic fluids with specific magnetic 

properties such as very high magnetization at saturation point or rheological properties 

involving high fluidity (very low viscosity). The sample with bigger density (1070 kg/ 

m3) also has a larger solid volume fraction (0, 059). Increasing the solid part/ fluid 

volume increases the density and viscosity of that fluid. A magnetic fluid with a larger 

magnetic part/ volume (0,031) has a higher magnetization at saturation point (0,0138 

A/m). The parameter always has sub-unitary values because inside the volume of the 

magnetic fluid, the percentage of the solid part is larger then that of the magnetic part. 

Responsible for this is the nonmagnetic layer at the surface of the particles. For the 

fluid samples studied, regardless of the magnetic and physic diameter, the nonmagnetic 

layer of particles has the same value: a = 0,83 nm. Good quality of a magnetic fluid is 

indicated by a high value of the conversion parameter. 

RR03 

A study on magnetic fluid viscosity 

Viorica Chioran 

University Babes-Bolyai - Cluj Napoca / Romania, Romania 

This paper shows the results of a study of the parameters that the viscosity of magnetic 

fluids depends on, in the absence of magnetic fields. Viscosity’s and shearing tension’s 

dependence on the rheologic component and shearing speed was verified for several 

samples of kerosene based magnetic fluid with the same dimensional distribution 

but various concentrations, at different temperatures. Experimental results show one 

situation where the sample P1 has a non-Newtonian character over a small interval of 

shearing speeds. An increase in fluid viscosity indicates that bonds between particles 

are formed inside the fluid. As shearing speeds increase these bonds disappear. 

Samples P and P 2 show Newtonian character over the shearing speed interval where 

viscosity remains constant. By comparing viscosity values of samples at different 

temperatures and shearing speeds, decreasing viscosity while increasing temperature 

is observed due to the activation energy of viscous flow. A linear increase of shearing 

tension with the increase of shearing speed was observed for the studied samples at 

different temperatures. The slope of this line can be used to determine the dynamic 

viscosity’s value. For the considered samples, viscosity strongly depends on several 

factors: density, concentration, temperature (by Arrhenius’s Law) and shearing speed (by 

Newton’s equation). 

RR04 

RR05 

RR06 

Theoretical design of magnetic energy harvesting module 

Kunihisa Tashiro*, Hiroyuki Wakiwaka and Yu Uchiyama 

Shinshu University, Japan 


Magneto-motive force and torque analysis of squirrel cage induction 

motor with rotor or stator faults 

Cheol Soo Goo 1 , Seok-myeong Jang 2 and Yu Seop Park 2 

1 

Insturmentation and Control Assessment Department, Korea Institute of Nuclear 

Safety, Korea 

2 

Electrical Engineering, Chungnam National University, Korea 

Torque characteristics of high voltage induction motor are simulated under the 

condition of under voltage and broken rotor bars. The motor is high voltage squirrel 

cage induction type for driving force of pumps and valves in nuclear power plant. In 

the simulation, a rotor with health and broken bars, stator winding deterioration and 

voltage drop 25% alone and combination with bar faults were used. Then the results 

were analyzed. The effects of rotor faults on the torque-speed curve were compared 

according to the number of the rotor faults. The results revealed that voltage drop and 

the number of the rotor fault at high speed span is directly proportional to its effect on 

the curve, but the curve indicated the opposite at the low speed span due to the rotor 

impedance increase. In stator, winding faults made a distortion of the phase magnetomotive 

force and reduction of co-energy at the gap which cause vibration, harmonics 

and total power decrease. 

Evaluation of materials degradation of ferromagnetic steels for various 

magnetized states using a hysteresis scaling law 

Satoru Kobayashi*, Yusuke Ishibashi and Ryo Baba 

Department of Materials Science and Engineering, Iwate University, Japan 

We have examined a hysteresis scaling behavior of magnetic minor hysteresis loops 

for ferromagnetic low carbon steels under DC-biased magnetic field and/or remanent 

magnetization state. For all minor loops with dominant contribution of irreversible 

Bloch wall motion, a scaling relation between the hysteresis loss and maximum 

magnetization shows the same curve from very low to high magnetization regime, 

suggesting the invariant pinning mechanism for the irreversible wall motion. In the 

intermediate magnetization regime, the relation follows the usual Steinmetz law with 

a power-law exponent of about 1.5, whose coefficient increases with defect density. 

The method using a hysteresis scaling can be a useful technique of evaluating materials 

degradation of ferromagnetic steels in an unknown magnetic state, which is commonly 

encountered on on-site measurements. 

Energy harvesting is a key technology to build a sustainable society. In previous 

paper, we focused on a magnetic power-line noise as a reusable energy. In this paper, 

we present a theoretical design method of magnetic energy harvesting module. This 

module consists of an air-core coil and resonant capacitor. With a simple RLC circuit 

model, we derive a equation of the harvesting energy as a function of coil size. In 

order to demonstrate the magnetic field, a uniform magnetic field is generated by our 

developed coil system. From the experimeted results, we successfully demonstrated the 

energy harvesting of 100 mW from a magnetic field of 0.09 mT at 60 Hz. This value 

is good in agreement with the estimated results. The harvested energy is proportional 

to the square of the magnetic flux density. However, ICNIRP2010 provide a guide 

line for human helth that an acceptable level in a public space is 0.2 mT at power-line 

frequency. We also reveal the required coil size to harvest a demanded energy. 


Poster Thursday



RR07 

A study on detecting and determining the shape of small axial cracks 

by using magnetic flux leakage in ndt system of pipe 

Hui Min Kim and Gwan Soo Park* 

School of Electronic and Electrical Engineering, Pusan National University, Korea 

There is the source of energy that is used widely all over the world, which is oil and 

natural gas. Oil and gas is supplied for industries or home consumers through pipelines. 

Most pipelines are laid to underground and exposed the external environment. By 

these conditions pipelines have some bad effects like the metal loss, corrosions and 

any other damages. For preventing accidents, these defects have to be detected by the 

Non-destructive testing(NDT). The magnetic flux leakage(MFL) method among the 

NDT methods is suitable for testing pipelines which the magnetic characteristic of 

has high magnetic permeability. The system that MFL method applies to is called the 

pipeline inspection gauge, MFL PIG. The previous MFL PIG has high performance 

for detecting the metal loss and corrosions. But MFL PIG cannot detect the cracks 

which occurred by the difference of pressure between the inside and outside of 

pipelines and the shape of is long and very narrow. Cracks occures frequently in the 

pipelines and the risk of the accident from the cracks is higher than that from the metal 

loss and corrosions. The circumferential MFL(CMFL) PIG performs magnetic field 

circumferentially and can maximize the magnetic flux leakage at the cracks. 

RR08 

Control of working temperature of isothermal magnetic entropy 

change by hydrogen absorption into La 0.8Nd 0.2(Fe 0.88Si 0.12) 13 for magnetic 

refrigerant 

S Fujieda 1 *, A Fujita 2 , K Fukamichi 1 and S Suzuki 1 

1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku Univ., Japan 

2 Dept. of Materials Science, Graduate School of Engineering, Tohoku Univ., Japan 

Hydrogen absorption into La 0.8Nd 0.2(Fe 0.88Si 0.12) 13 has been investigated to obtain large 

magnetocaloric effects (MCEs) near room temperature for applications to magnetic 

refrigeration. La(Fe 0.88Si 0.12) 13 exhibits large MCEs just above the Curie temperature 

T C = 195 K because of the itinerant-electron metamagnetic (IEM) transition [1]. The 

MCEs due to the IEM transition are enhanced by the partial substitution of Nd for La 

[2]. It was confirmed that T C of La 0.8Nd 0.2(Fe 0.88Si 0.12) 13 is increased from 193 K to 318 

K by hydrogen absorption with keeping the IEM transition because the unit cell volume 

is expanded. Note that the isothermal magnetic entropy change ΔSm due to the IEM 

transition in a magnetic field change of 2 T for La 0.8Nd 0.2(Fe 0.88Si 0.12) 13H 1.1 was evaluated 

to be about -23 J/kg K at T C = 288 K, which is larger than ΔSm = -19 J/kg K at T C = 276 

K for La(Fe 0.88Si 0.12) 13H 1.0. The relative cooling power RCP = 179 J/kg of the former 

also is larger than 160 J/kg of the latter. Accordingly, it is concluded that the partial 

substitution of Nd improves the MCEs near room temperature. 

[1] A. Fujita et al., Phys. Rev. B 67 (2003) 104416. [2] S. Fujieda et al., Mater. Sci. Forum 561-565 (2007) 1093. 

RR09 

Characteristic analysis of induction motor for electric vehicle 

according to electric loading and magnetic loading 

Ki Young Sung 1 and Ki-chan Kim 2 * 

1 SPG Co,. Ltd., Korea 

2 Hanbat national university, Korea 

In the paper, an inductive motor for electric vehicle that was designed for compact 

car modification was selected as the basic model, and its performance change was 

examined according to the change in the electric and magnetic loading related to the 

rotor slot. The characteristic changes according to the change in the loading were 

analyzed for two speed ranges: the low speed (near the base speed) and the high speed 

(maximum speed with field weakening control). To provide the characteristic analysis 

conditions according to the change in the slot shape of the reference model, the rotor 

bar depth was changed with the rotor teeth width fixed to vary the electric loading, and 

the rotor teeth width was changed with the rotor bar area fixed to vary the magnetic 

loading. The characteristics of the inductive motor were analyzed via the analysis 

of the characteristics according to the parameters of the equivalent circuit based on 

the magnetic circuit method and via the electromagnetic analysis based on the finite 

element method to consider the nonlinear characteristic of the motor parameters. 

[1] Z.Zhang, F.profmo, a. tenconi, 'Improved design for elelctric vehicle induction motors using an optimisation procedure'. 

Electric Power Applications, IEE Proceedings, vol, 143, pp.410-416, 1996 [2] T. Wang, P. Zheng, Q. Zhang, and S. Cheng, 

'Design Characteristics of the induction motor used for hybrid electric vehicle'. IEEE Tracnsaction on Magnetics, vol. 41, 

pp. 505-508, 2005 [3] I. Boldea and S. A. Nasar, 'The induction machine handbook'. Boca Raton, CRC Press, 2002 


RR10 

Torque characteristics of interior permanent magnet synchronous 

motor for electrical hydraulic power steering system 

Su-jin Hwang 1 and Ki-chan Kim 2 * 

1 Daedong movel company, Korea 

2 Hanbat national university, Korea 

In the paper, a 12 V-DC interior permanent magnet synchronous motor for electric 

hydraulic power steering (EHPS) was designed for the purpose of improving its torque 

performance. The EHPS is a steering system that uses the battery power of the vehicle, 

which is weaker than the power of the hydraulic power steering system. Because of 

the spatial limitation, the IPMSM, which has high-power characteristic and excellent 

performance within the field weakening area at a high rotating speed, is advantageous. 

To improve the torque performance, the average torque was increased by increasing 

the rotor size. In addition, because the torque ripple is detected as vibration when 

the steering wheel is operated, the shape of the barrier was modified to change the 

inductance element of the axis and reduce the torque ripple. The optimally designed 

model characteristics were analyzed using the finite element method to comparatively 

analyze the parameters. It is expected that this study will be important reference data to 

understand the characteristics of the IPMSM as well as of the EHPS. 

[1] Tomy Sebastian, Vineeta Gangla, 'Analysis of Induced EMF Waveforms and Torque Ripple in a 

Brushless Permanent Magnet Machine,' IEEE Trans. on Industrial Applications, Vol. 32, No. 1, 1996. [2] 

A. M. Elrefais, T. M. Jahns and D. W. Novotny, 'Analysis of Surface Permanent Magnet Machines with 

Fractional Slot Concentrated Windings', IEEE Trans on Energy Conversion, vol. 21, no. 1, pp. 34-43, 2006 

RR11 

Edge auxiliary teeth design of stationary discontinuous armature PM- 

LSM with concentrated winding 

Yong-jae Kim 1 , Sung-jin Kim 1 * and Sang-yong Jung 2 

1 Department of Electrical Engineering, Chosun University, Korea 

2 School of Information and Communication Engineering, Sungkyunkwan University, Korea 

Recently, in order to resolve the problem of high cost, we have proposed the stationary discontinuous armature 

PM-LSM in which the armature is engaged only when accelerated and decelerated operations are necessary, 

when PM-LSM is used with long-distance transportation systems in factories [1]. As the armatures are 

arranged discontinuously in the PM-LSM, the number required is dramatically decreased. In this case, several 

stator blocks can be arranged at certain intervals within the overall running route. The space between the 

blocks without the stator is called the free-running section, and the mover in this section drives under its own 

inertia. However, the stationary discontinuous armature PM-LSM contains the edges which always exist as a 

result of the discontinuous arrangement of the armature [2]. For this reason, cogging force generated between 

the “entrance end” and the “exit end” has become a problem. Therefore, we have examined the edge cogging 

force by installing the auxiliary teeth at the armature’s edge in order to minimize the cogging force generated 

when the armature is arranged discontinuously. We obtain the edge cogging force by using 2-D numerical 

analysis with a FEM and also by adjusting the width, height and the length of pitch of auxiliary teeth. 

[1] Yong-Jae Kim, Masaya Watada, Susumu Torii and Daiki Ebihara, “Constant Load Angle Control of the Discontinuous 

Primary Linear Synchronous Motor without Position Feedback”, The Fourth <strong>International</strong> Symposium on LINEAR 

DRIVES FOR INDUSTRY APPLICATIONS, pp.113-116, 2003. [2]Yong-Jae Kim, Masaya Watada, Susumu Torii, Hideo 

Dohmeki and Daiki Ebihara, “The Influence which Outlet edge of the Discontinuous Primary Linear Synchronous Motor 

Exerts on the Drive of Secondary Mover”, The 5th <strong>International</strong> Power Electronics <strong>Conference</strong>, pp.859-864, 2005. 

RR12 

Inductively coupled LC resonators as displacement sensor 

Yongmin Kim and Kwang-ho Shin* 

Dept. of Information and Communication Engineering, Kyungsung University, Korea 

In this paper, we present novel displacement sensor composed of a pair of LC 

resonators. The LC resonator was formed by serial connection of 300-turn Cu wire 

wound on a rectangular NiZn ferrite (20 × 3 × 4 mm) core and SMD capacitor (3.2 × 

1.6 mm). The resonance frequencies of two resonators are adjusted to be identical with 

each other. By this, we could obtain the sensor output linearly dependent of distance 

between two LC resonators, because the mutual inductance is proportional to distance 

between two resonators in a few centimeters. The sensor was designed by a sequence 

of magnetic field simulation with a FEM tool (COMSOL) and circuit calculation with 

a SPICE. The sensitivity estimated by S = fr/D was about 480 kHz/m, where, fr and 

D are resonance frequency and distance between two resonators, respectively. The 

proposed sensor would be a promising displacement sensor when it takes an active part 

in an environment surrounded by serious electrical/magnetic noise, since it could be 

operated in extremely narrow frequency range.

RR13 

Magnetic NDE for sensitization of Inconel 600 alloy 

Hiroaki Kikuchi, Takaki Sumimoto, Yasuhiro Kamada and Satoru Kobayashi 

Faculty of Engineering, Iwate University, Japan 

Inconel 600 alloy, Ni base alloy, is used as steam generators in nuclear power plants, 

and sensitization occurs along grain boundary with heat treatment on this material. The 

sensitization causes a degradation of corrosion resistance and generates stress corrosion 

crack [1], [2]. Therefore nondestructive evaluation (NDE) technique for sensitization 

of Inconel alloy is quite important so as to keep the integrity of plants. Inconel 600 

alloy has usually paramagnetic property, however, it shows ferromagnetic properties 

along grain boundary when sensitization occurs: this means NDE using magnetism 

is possible. Thus, in this study, Inconel 600 alloys were heat treated at 873 K from 0 

to 400 hours and their magnetic properties were investigated in detail. Magnetization 

increases with increasing time of heat treatment and takes a maximum. On the 

other hand, coercivity decreases with the increase in time. We confirmed that only 

characteristics at the grain boundaries changes ferromagnetic by MFM observation. As 

trial for industrial application, heat treated Inconel 600 alloy has scanned by magnetic 

field sensor, and the changes of magnetization nondestructively were successfully 

obtained. The result indicates the feasibility of magnetic NDE for sensitization of 

Inconel 600 alloy. 

[1] M. Kowaka, H. Nagano, T. Kubo, Y. Okada, M. Yagi, O. Takaba, T. Yonezawa and K. Arioka, 

Nuclear Technologies, Vol. 55, pp. 394-404 (1981). [2] J. D. Wang, D. Gan, Materials Chemistry 

and Physics, Vol. 70, pp. 124-128 (2001). 

RR14 

Comparison of characteristics between the PM synchronous motor 

and the induction motor for electric vehicle 

Mi-jung Kim, Ik-sang Jang, Ki-doek Lee, Jae-jun Lee, Jeong-ho Han, Tae-chul Jeong 

and Ju Lee* 

Hanyang University, Korea 

This paper presents the characteristics over a wide speed range of the interior permanent magnet 

synchronous motor(IPMSM) and the induction motor(IM) for an application of electric vehicle 

drive. In generally, IPMSM have higher performance than IM. The performance: torque, 

efficiency, power factor etc. are compared at rated speed of 2,843rpm and maximum speed of 

10,000rpm. The induction motor operating constant speed is not need to consider the control 

property; however, the adjustable speed drive applications such as traction motor are should 

be deliberated for control. In this paper, the characteristics of IPMSM and IM controlled by 

space vector PWM are illustrated and verified by experiment. In case of IPMSM, the efficiency 

map was made up through driving simulation considering the actual control. It was carried out 

MTPA control until constant torque operating region and applied the field weakening control 

under constant power region. In case of induction motor, V/f control maintained a constant ratio 

of voltage versus current was carried out until constant torque operating region and applied 

the constant voltage variable frequency control under constant power region. As illustrated in 

Figure 1, overall efficiency of IPMSM has high level than IM about 5%. 

[1] Z. Q. Zhu and David Howe, 'Electrical Machines and Drives for Electric, Hybrid, and Fuel cell Vehicles', Proceedings of the 

IEEE, Vol. 95, No. 4, pp 746-765, April 2007. [2] J. Herbst, J. Hahne, H. Jordan, H. Liu, A.Gattozzi and Ben Wu, 'Challenges in 

the Design of a 100 kW Induction Motor for a PHEV Application', Vehicle Power and Propulsion <strong>Conference</strong>, pp 408-413, 2009. 

RR15 

Comparison of simultaneously measured pulse waveforms from both 

hands using permanent magnet-hall pulsimeter sensors 

Sang-suk Lee 1 , Jong-gu Choi 2 , Il-ho Son 1 , Keun-ho Kim 1 , Nam-kyu Lee 1 and Hyunsung 

Cho 1 

1 Oriental Biomedical Engineering, Sangji University, Korea 

2 Eastern-Western Biomedical Engineering, Sangji University, Korea 

Two radially arterial pulses of dual hands using the prototype of a clamping clip 

pulsimeter equipped with permanent magnet and Hall device are compared and 

analyzed. The phase difference of two pulse wave signals is dominantly presented 

from the simultaneous measuring clinical pulse wave signals for twenty two male 

participants at their 20’s. It is possible to analyze that the fast and slow pulse wave for 

right hand and left hand depend on the muscle property of arms rather than the total 

length of blood vessel due to cardiovascular circulatory system. 

[1] S. S. Lee, M. C. Ahn, and S. H. Ahn, J. Magnetics. 14, 132 (2009). [2] M. F. P. O’Rourke, R. P. 

Kelly, A. P. Avolio, 'The Arterial Pulse', 1st Ed.; Lea & Febiger: Philadelphia, PA, USA, 1992 [3] S. W. 

Kim, Y, G, Choi, H. S. Lee, D. H. Park, D. G. Hwang, S. S. Lee, G. W. Kim, S. G. Lee, and S. J. Lee, J. 

Appl. Phys. 99, R908 (2006). 

RR16 

RR17 


A study on new permanent magnet configuration for high thrust 

density in permanent magnet synchronous linear motor 

Taewoo Kim and Junghwan Chang* 

Electrical Engineering, Dong-A University, Busan, 604-714, Korea, Korea 

WITHDRAWN 

Design of stationary pole pieces in a coaxial magnetic gear 

Daekyu Jang and Junghwan Chang* 

Electrical Engineering, Dona-A University, Saha-gu, Busan, 604-714, Korea, Korea 

Magnetic gears have been proposed by unique advantage compared with mechanical 

gears, such as contactless power transmission. In addition, they can limit a torque 

under overloaded condition and have excellent performances on noise, vibration and 

reliability [1]. However, their use in industries has been very limited due to poor torque 

density, low transmission ratio and transmitted toque performances. Of magnetic gears, 

a coaxial magnetic gear is a common configuration and extensively studied for its 

relative high performances [2]. It is consist of inner rotor, outer rotor and stationary 

pole pieces in between the rotors. The stationary pole pieces have an important role in 

torque transmission by modulating the air gap flux density distribution adjacent to inner 

and outer rotor. However, they also generate unwanted harmonics resulting in torque 

ripples and vibration. This paper proposes variants of stationary pole pieces to gain 

high performances in torque transmission. It also has mechanical and manufacturing 

advantages in transmitting torque by a structure combining each pole pieces. The finite 

element analysis shows the produced torque has reduced harmonic components in both 

sides of rotors. 

[1] K.Atallah, S.D. Calverley and D. Howe, “Design, analysis and realization of a high performance 

magnetic gear”, IEEE proc.-Electr. Power Appl, vol. 151, No. 2, pp.135-143, March. 2004. [2] 

Noboru Niguchi, Katsuhiro Hirata, Masari Muramatsu and Yuichi Hayakawa, “Transmission 

Torque Characteristics in a Magnetic Gear,” ICEM conf, pp 1-6, sept. 2010. 

RR18 

Design techniques for reducing torque ripple in permanent magnet 

flux switching motor 

Daohan Wang 1 , Xiuhe Wang 2 and Sang-yong Jung 1 * 

1 Sungkyunkwan University, Korea 

2 Shandong University, China 

Permanent magnet flux switching motor (PMFSM) is a novel double salient machine 

which employ the PM instead of the field winding for excitation and contains only one set 

of armature winding so has the advantage of low cost power converter and extreme high 

efficiency. It has a potential for taking place of BLDC in some applications, such as fans 

and air ventilation machines. Due to the different structure and operation principle from 

traditional permanent magnet machine, the generated torque ripple in PMFSM is very 

critical and rather unique compared to the common PM machines. In this paper, the design 

techniques of reducing the torque ripple in PMFSM has been presented. Different kinds 

of design approaches have been presented to reduce the torque ripple with comparing the 

mean output torque. Analytical method is first presented to investigate the influence and 

determine the design parameters thus reduce the computational effort. Then FEA simulation 

is employed to validate the analysis above. Finally, time stepped FEA simulation is being 

employed to investigate the performance with different approaches adopted. 

[1] Z. Q. Zhu, A. S. Thomas, J. T. Chen, and G. W. Jewell, “Cogging Torque in Flux-Switching Permanent 

Magnet Machines,” IEEE Trans. Magn., vol. 45, no. 10, pp. 4708-4711, Oct. 2009. [2] Z. Q. Zhu, J. T. Chen, 

D. Howe, S. Iwasaki, and R. Deodhar, “Design of multi-tooth flux-switching permanent magnet brushless ac 

machines for low speed direct drives,” IEEE Trans. Magn., vol. 44, no. 11, pp. 4313-4316, 2008. 


Poster Thursday



RR19 

The analysis of line-start permanent magnet machine with saliency 

ratio 

Kwang Hee Kim, Jian Li and Yun Hyun Cho* 

Dong-A University, Korea 

RR20 

RR21 

WITHDRAWN 

Analysis of non-linear characteristics of linear compressor 

Park Daegeun and Cho Yunhyun* 

Dong-A University, Korea 

WITHDRAWN 

Torque harmonics and reduction design characteristics of induction 

motor for electric vehicle propulsion 

Kyung-won Jeon 1 , Seungho Lee 1 , Yong-jae Kim 2 and Sang-yong Jung 1 * 

1 School of Electronic and Electrical Engineering, Sungkyunkwan Univ., Korea 

2 Dept. of Electrical Engineering, Chosun University, Korea 

This paper deals with torque harmonic characteristics of induction motor for electric vehicle (EV). 

For calculate phase stator harmonic leakage flux of a three phase induction motor, an analysis method 

is determine relationships with stator teeth design. In particular, torque harmonics including EMF 

harmonics at whole speed ranges are analyzed by the finite element method (FEM). Torque harmonic 

components are identified with Fourier fast transform (FFT). Torque harmonics are generated due 

to the different phase windings interaction and they can be reduced by applying a stator teeth design. 

The electromagnetic field and corresponding harmonics of an electrical machine are calculated using 

the FEM, the harmonic winding factors show how the torque harmonics can be reduced significantly 

by good stator teeth design. The novel design methods to compensate the specified torque harmonics 

are proposed. Then, its effectiveness is clarified according to the representative control strategies for 

induction motor such as maximum torque per ampere (MTPA) and flux-weakening control. 

[1] Lee S., Kim Y.-J., Jung S.-Y., “Numerical Investigation on Torque Harmonics Reduction of Interior PM Synchronous 

Motor With Concentrated Winding”, IEEE Trans on. Magnetics, vol.48, no.2, pp.927-930, Feb. 2012. [2] Yamazaki K., 

Suzuki A., Ohto M., Takakura T., Nakagawa S., “Equivalent Circuit Modeling of Induction Motors Considering Stray 

Load Loss and Harmonic Torques Using Finite Element Method”, IEEE Trans on. Magnetics, vol.47, no.5, pp.986-989, 

May. 2011. [3] Bianchi N., Alberti L., “MMF Harmonics Effect on the Embedded FE Analytical Computation of PM 

Motors”, IEEE Trans on. Industry Applications, vol.46, no.2, pp.812-820, Mar-Apr. 2010. 


RR22 

Numerical analysis on iron loss and pm loss of permanent magnet 

synchronous motor considering the carrier harmonics 

Yun-ho Jeong 1 , Kyung-won Jeon 1 , Yong-jae Kim 2 and Sang-yong Jung 1 * 

1 School of Electronic and Electrical Engineering, Sungkyunkwan Univ, Korea 

2 Dept. of Electrical Engineering, Chosun University, Korea 

In this paper, decisive influences of the inverter harmonic on iron loss characteristic for PMSM (Permanent 

Magnet Synchronous Motor) are numerically investigated with the FEM (Finite Element Method). 

Particularly, analysis is carried out based on a multi-layer buried PMSM, which is newly designed for EV 

drive system and its rotor contains ferrite magnets. First of all, not only the design criteria and the specification 

of the designed PMSM but also the features of the motor like torque ripple, Back-EMF are represented. In 

addition, the remarkable iron loss analysis result, that is obtained using 3-D FEM considering skewed stator 

structure, is covered in priority. Then its each harmonic component is identified using the FFT (Fourier Fast 

Transform) and that is compared with iron loss characteristic in case of sinusoidal input current which is 

not include harmonic component. Finally, the efficiency at each operating point is calculated considering 

loss analysis results. Meanwhile, entire analysis is performed through various operating conditions using 

intrinsically real input current values implemented by testing performance of the manufactured model. 

[1] Z.Q.Zhu, Y.S.Chen, D.Howe, 'Iron Loss in Permanent-Magnet Brushless AC Machines Under Maximum Torque 

Per Ampere and Flux Weakening Control', IEEE Trans. on Magnetics, vol. 38, No. 5,pp. 3285-3287, Set. 2002. [2] 

Katsumi Yamazaki, Shinjiro Watarim 'Loss Analysis of Permanent-Magnet Motor Considering Carrier Harmonics 

of PWM Inverter Using Combination of 2-D and 3-D Finite-Element Method', IEEE Trans. on Magnetics, vol. 41, 

No. 5,pp. 3285-3287, May. 2005. [3] G. Ombach, J. Junak, 'Torque ripple optimization of skewed IPM motor for 

field weakening operation', Electrical Machines and Systems (ICEMS) 2011, pp. 1-7, Aug. 2011. 

RR23 

Defect depth estimation based on the analysis of interference defects 

on the underground gas pipelines 

Min-Ho Kim 1 , Bok-Jin Oh 1 , and Doo-Hyun Choi 2 * 

1 

Graduate School of Electrical Engineering and Computer Science, Kyungpook 

National Univ., Korea 

2 

School of Electronics Engineering, Kyungpook National Univ., Korea 

Underground gas pipelines have corrosions and deformations due to both the natural 

causes such as moisture and ground pressure and the artificial causes such as faulty 

construction, etc. So, periodic pipeline inspection is essential. In NACE (national 

association of corrosion engineers) standard, it is advised to replace the pipeline when 

a defect’s depth is over 50% of the pipeline’s thickness. Therefore, the study to analyze 

the defect’s depth and its progress is meaningful. Especially when defects more than 

two are closely located, the interaction among these defects accelerates the progress of 

defection. In this paper, the interference defects on underground pipelines are analyzed 

and their depths are estimated effectively. Experimental results show that the proposed 

method can effectively estimate the depth of the interference defects. 

RR24 

Comparison on electromagnetic losses of super high speed PM motor/ 

generator with slot and slotless stators 

Jin Hak Jang 1 , Jian Li 2 and Yun Hyun Cho 1 * 

1 Dong-A University, Korea 

2 Dong-A University, China 

WITHDRAWN

RR25 

A study on Voltage-PWM control of switched reluctance generator at 

low speed 

Sun Ning 1 , Dawoon Choi 2 , Jian Li 1 and Yunhyun Cho 2 * 

1 DongA-university, China 

2 DongA-university, Korea 

This paper is a study on switched reluctance generator’s control method---Voltage- 

PWM. It can be used to regulate the current to a desired value by varying the average 

applied voltage in the switched reluctance generator . The advantages of Voltage- 

PWM control at low speed are more than high speed which may make the application 

of PWM difficult. The switched reluctance machine can operate as a generator as well 

as a motor by simply changing the firing angles. Some main control methods we often 

used are Chopped Current Control (CCC), Angular Position Control (APC) and PWM 

Control . The controller could regulate control variables, such as current level, turn-on 

and turn-off angles, supply voltage and so on. Different control methods will be carried 

out by regulating some variables in different conditions. For example, at low speed, the 

d.c link voltage is controlled by varying the set-point current or the duty-cycle and at 

high speed by varying the control angles. Because of excitation current is closely linear 

relation to duty cycle, so many applications determine this control method. 

[1]Miller, T.J.E. Electronic Control of Switched Reluctance Machines. MPG Books Ltd, Bodmin, 

Cornwall. 2001. [2]K.Kannan , Dr.S.Sutha. The 4th <strong>International</strong> Power Engineering and Optimization 

<strong>Conference</strong> (PEOCO2010), ShahAlam, Selangor, Malaysia.23-24 June 2010. [3] Jianzhong Sun, 

Fengxian Bai, Special type electroc machine and control China waterpub press, 2005.137-143. 

RR26 

The measurement procedure of the equivalent core loss in a PM motor 

Guo Jhih Yan 1 *, Ming-hung Jian 1 and Chia-sheng Huang 2 

1 Micro/Meso Mechanical Manufacturing R&D Section, Metal Industries Research & 

Development Centre, Taiwan 

2 Codent Tech Co. Ltd, Taiwan 

For the development of high efficiency motor, the core loss decrease is one of the most important tasks. 

However, the calculated core loss in the design stage is not so accurate because the specification provided 

by material manufacturer usually obtained by ideal test condition in simple geometry, i.e. single sheet tester 

and toroidal tester. Therefore, a method that can measure the core loss with the practical shape of motor 

stator/rotor core includes every aspect of the manufacturing effects is required. This paper proposed a 

refined procedure based on torque metric method. Among several proven measuring methods, it is a directly 

measuring method that can be applied to the actual motor. Typical torque method uses a motor driving a 

specimen at a specific speed and then measures the drag torque. However, it is time consuming and requires 

higher precision torque meter. Instead, the proposed method measures the speed-power characteristic curve 

of the driving motor with/without the test motor. From the difference of the speed-power characteristic, 

the core loss at various speeds can be obtained. Several conventional PM motors are taking as examples to 

demonstrate this procedure and to investigate the core loss influenced by manufacturing. 

[1]N. Stranges, and R. D. Findlay, “Measurement of Rotational Iron Losses in Electrical Sheet,” IEEE 

TRANSACTIONS ON MAGNETICS, Vol. 36, No. 5, Sep, 2000, pp. 3457-3459. [2]W. Arshad, etc, “Incorporating 

lamination processing and component manufacturing in electrical machine design tools,” in Industry 

Applications <strong>Conference</strong>, 2007. 42nd IAS Annual Meeting. <strong>Conference</strong> Records, 2007, pp. 94-102. [3]Youguang 

Guo, etc, “Measurement and Modeling of Rotational Core Losses of Soft Magnetic Materials Used in Electrical 

Machines: A Review,” IEEE TRANSACTIONS ON MAGNETICS, Vol. 44, No. 2,Feb, 2008, pp. 279-291. 

RR27 

MFL signal enhancement based on exponential smoothing 

Su-yeon Jeong 1 , Jong-hwa Kim 2 and Doo-hyun Choi 2 * 

1 

Graduate School of Electrical Engineering and Computer Science, Kyungpook 

National Univ., Korea 

2 

School of Electronics Engineering, Kyungpook National Univ., Korea 

Nowadays, as industrialization is in progress worldwide and economy grows rapidly, 

demand for the energy supply of oil and gas has also increased. Currently, over millions 

of kilometers of underground gas pipeline has been established worldwide. The 

maintenance of pipeline is needed for the efficient supply of energy, but in reality, it is 

impossible for human experts to investigate all the underground pipelines in order to 

confirm whether a pipe has deterioration or damage because of the pipe’s geographical 

position. So, automatic nondestructive testing methods by using MFL (magnetic 

flux leakage) signal are currently studied actively to detect and extract defects on the 

pipeline. The raw signals acquired from MFL sensors contain the signals of defects, as 

well as noise and distortion caused by various underground environments. In this paper, 

MFL signal is enhanced by using several smoothing techniques. Through experiments, 

it is confirmed that the distortion of raw signal by noise canceling can be reduced. 

RR28 

RR29 

RR30 


Electromagnetic separation of the brown coal ash of thermal power 

stations 

Shavkat Malikov 1 , Valeriy Pikul 1 , Nuranya Mukhamedshina 1 , Vladimir Sandalov 2 and 

Elvira Ibragimova 2 * 

1 Muclear physics, Institute of Nuclear Physics, Uzbekistan 

2 Radiation physics of solids and material science, Institute of Nuclear Physics, 

Uzbekistan 

Tens millions of brown coal ash have accumulated near thermal power stations (TPS) in 

Uzbekistan, so their utilization has become quite actual. So far the ash is used for cement. 

However the ash is well known to contain a large amount of valuable elements, including 

~3.13%Fe 2O 3 in Russian coal. Element analyses of the brown coal ash from Angren TPS 

were done with the neutron activation techniques and 3.6%Fe, 0.084%Mn, 0.063%Zr and 

also 0.023% of rare earth elements have been determined. The ash samples were undergone 

to electromagnetic separation, and the magnetic fraction was 3.7%, where the content of 

Fe increased to 58%. Then the magnetic fraction was separated with the standard screen 

grader into 7 classes from 0.4 to 0.05mm. Two times increase of the contents of Fe and rare 

earth elements have been found in the fine fractions of 0.1-0.05mm. Optical absorption 

spectroscopy of water solutions of the magnetic fractions has revealed the presence of Fe 2+ 

and Fe 3+ ions. Microscopic analysis of the fine fractions has shown that there are black iron 

microspheres of 0.02-0.05mm sizes, which can be used for cleaning of technological liquid 

waste by means of the high gradient magnetic field, and powder metallurgy. 

Studies on viscidity in ferrofluids of Fe3O4 Han Gu 1 , Zhaozhen Jiang 2 , Aimei Zhang 3 and Xiaoshan Wu 2 

1 

Advance Functional Materials Lab and Department of Physics, Changshu Institute 

of Technology, Changs, China 

2 

Lab of Solid State Microstructures, Dept Physics, Nanjing University, China 

3 

College of Science, Hohai University, China 

Fe 3O 4 nanoparticles with superparamagnetic properties are synthesized by sol-gel 

approach. Fe 3O 4 nanoparticles are coated using the amorphous silica. The viscidity 

of the coated Fe 3O 4 nanoparticles increases as the particles is incorporated in the 

impregnant, which may due to the magnetic interactions. At room temperature, the 

ferrofluid viscidity increases momotonically with increasing the concentration of 

Fe 3O 4 nanoparticles, the ratio of surface activity. With rising the temperature, the 

ferrofluid viscidity becomes larger. The applied magnetic field has also effects on the 

ferrofluid viscidity. The switching process of the applied magnetic field may increase 

the ferrofluid viscidity, although the ferrofluid viscidity increases with increasing the 

applied magnetic field. Dynamic properties of the magnetic particles in the impregnant 

are also discussed in the present. 

Non-contact magnetic evaluation of ferromagnetic plate and its 

compensation of unknown air gap 

Young-hak Kim 1 and Kwang-ho Shin 2 * 



Korea 

This paper represents a magnetic hysteresis model-assisted measurement method 

for non-contact evaluation of ferromagnetic plates in the case of the air gap between 

the test sample and the sensor probe is unknown. Our method involves measuring 

hysteresis loops from a test sample using a sensor probe in close proximity to the 

sample and measuring inductance spectra according to the various air gap. The sensor 

outputs were simulated based on a magnetic hysteresis model (Jiles-Atherton model) 

to describe the magnetic property of the sample. In this study, the measurement was 

applied to characterize a series of Fe-C samples. However, it is hard to confirm the 

permeability of a sample when the air gap is unknown, since the magnetic resistance 

of magnetic circuit composed of the sample and the sensor probe is affected by air 

gap size. The main idea of our study is that the frequency spectrum of inductance of 

the magnetic circuit is unaffected when the air gap is adequately small, even if the 

amplitude of inductance is directly dependent on air gap. The magnetic hysteresis 

measured with unknown air gap was compensated by measured inductance spectra, 

and was found to agree with nonlinear FEM analysis. 


Poster Thursday

Poster Friday 


RR31 

The several analysis techniques of high speed induction motor for 

copper die casting 

Do-kwan Hong 1 *, Jae-hak Choi 1 , Byung-chul Woo 1 , Dae-hyun Koo 1 and Chan-woo 

Ahn 2 

1 Korea Electrotechnology Research Institute, Korea 

2 Dong-A University, The department of mechanical engineering, Korea 

RR32 

SA01 

WITHDRAWN 

Effect of magnetic reynolds number variation on MHD convection 

inside an enclosure 

Mohsen Pirmohammadi* 

MAPNA Group, Iran 

Numerically investigation is carried out for magnetohydrodynamics natural convection 

in an enclosure. The vertical walls are maintained isothermal at different temperatures 

and the other walls are adiabatic. The magnetic field is applied horizontally. The non 

linear governing equations for the fluid flow and heat transfer are solved for three 

magnetic Reynolds numbers (10-5, 10-3 and 0.1). The Rayleigh number, the Hartmann 

number and the Prandtl number are considered 105, 80 and 0.01, respectively. A 

finite volume code based on Patankar's SIMPLER method is utilized. It is found that 

when the magnetic Reynolds number (Rem) is very low (10-5 and 10-3) the magnetic 

field distribution in the cavity is not affected by flow field and as Rem increases the 

magnetic field in x and y direction is not constant. Also it is observed that as Rem 

increases the rate of heat transfer changes. 

Magnetic annealing effects on properties of the multilayer BaTiO3 / 

CoFe2O4 thin films 

Yuqiang Dai 1 , Jianming Dai 1 *, Xianwu Tang1 and Qiangchun Liu 2 

1 

Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese 

Academy of Sciences, China 

2 

School of Physics and Electronic Information, Huaibei Normal University, China 

Multilayer BaTiO 3/CoFe 2O 4 thin films are prepared via chemical solution deposition 

method with and without magnetic field annealing process, respectively. The 

microstructural, magnetic, dielectric and the ferroelectric properties of the films are 

investigated. It is observed that the dielectric constant, polarizations and magnetizations 

of the multilayer thin films are improved with magnetic field annealing process. 

Moreover, for the magnetic field annealing films, the saturation magnetization with 

measuring magnetic field vertical to the film surface is much higher than that parallel 

to the film surface. 


SA02 

Magnetoelectric CoFe2O4-PZT thin film composites grown by pulsed 

laser deposition 

Ioanna Giouroudi 1 *, Mohammed Alnassar 2 , Roland Groessinger 3 and Juergen Kosel 2 

1 

Institute of Sensor and Actuator Systems, Vienna University of Technology, Austria 

2 

Division of Physical Sciences and Engineering, King Abdullah University of Science 

and Technology, Saudi Arabia 

3 

Institute of Solid State Physics, Vienna University of Technology, Austria 

SA03 

Synthesis and magnetic property of multiferroic DyMnO 3 

nanoparticles in mesoporous silica 

Takayuki Tajiri 1 *, Kenta Hamamoto 2 , Yuhki Ando 2 , Hiroyuki Deguchi 2 , Masaki Mito 2 

and Atsushi Kohno 1 

1 Faculty of Science, Fukuoka University, Japan 


Multiferroic compound DyMnO 3 shows antiferromagnetic ordering with T N ~ 40 K and 

Dy spin ordering below about 6 K. The ferroelectricity is attributed to lattice modulation 

accompanied by the antiferromagnetic order. We are interested in the size effect on 

DyMnO 3 nanoparticles with particle size of a few nano-meters. We synthesized DyMnO 3 

nanoparticles and investigated their magnetic property. The DyMnO 3 nanoparticles were 

synthesized in the pores of a mesoporous silica SBA-15 with pore diameter of about 8 

nm. SBA-15 was used as a template to equalize the particle size in the fabrication of the 

DyMnO 3 nanoparticles. The X-ray diffraction pattern for DyMnO 3 nanoparticles shows 

some broad Bragg peaks corresponding to crystal structure of DyMnO 3 bulk crystals. The 

size of nanoparticles was estimated to be about 10 nm based on the Bragg peaks and using 

Scherrer’s equation. The temperature dependence of DC magnetic susceptibilities for the 

nanoparticles exhibited a magnetic irreversibility between field-cooled susceptibility and 

zero-field-cooled one below about 40 K and an increase in susceptibilities due to magnetic 

ordering among the Dy spins below about 5 K. The magnetization curves exhibited 

hysteresis loop below blocking temperature. DyMnO 3 nanoparticles were successfully 

synthesized with size of about 10 nm and showed superparamagnetic behaviors. 

SA04 

WITHDRAWN 

Magnetic properties of Co 1-xMn xFe 2O 4 (x=0-0.5) - PZT thin films 

fabricated by sol-gel spin coating method 

M. Khodaei, S. A. Seyyed Ebrahimi* and R. Vaghar 

Center of Excellence for Magnetic Materials, School of Metallurgy and Materials,, 

University of Tehran, Iran 

Co (1-x)Mn xFe 2O 4 (x=0-0.5) thin films were fabricated on PZT layer by sol-gel spin 

coating method in order to investigation of influence of Mn-substitution in C oFe 2O4 

on the magnetic properties. The films were fabricated on the PZT layer which was 

previously fabricated on Pt(111)/Ti/SiO 2/Si substrate using the same method. The phase 

identification of the samples was studied by X-ray diffractometry analysis. Magnetic 

properties of the samples were also measured using a vibrating sample magnetometer.

SA05 

M doping element localization by the molecular field theory in the 

Ga xFe 2-xO 3:M thin films 

Christophe Lefevre 1 *, Ran Hee Shin 2 , Ji Hye Lee 2 , Seol Hee Oh 2 , Alexandre 

Thomasson 1 , Francois Roulland 3 , Christian Meny 1 , William Jo 2 and Nathalie Viart 3 

1 CNRS, France 

2 Department of Physics, Ewha Womans University, Korea 

3 Universite de Strasbourg, France 

Magnetoelectric materials open the way towards new applications through controlling 

magnetic or electric polarization with electric or magnetic field, respectively. 

Ga 0.6Fe 1.4O 3 is predicted magnetoelectric with non zero magnetization at room 

temperature. High quality GFO thin films having similar magnetic properties to 

those of the bulk materials have been produced only recently. However their electric 

properties failed to be properly characterized until now because of important leakage 

currents originating from a hopping mechanism between Fe 2+ and Fe 3+ within the 

structure. Recently, we succeeded to strongly lower the leakage currents of these films 

by chemical doping. The determination of the cationic distribution within the structure 

is a key point for the knowledge of these phases, because it is at the origin of the 

evidenced magnetic and electrical properties of these materials. We present here an 

original approach to determine the localization of the M doping element based on the 

molecular field theory. Different modeling associated with the different substitution 

possibilities have been performed within the frame of this theory and are compared 

with the experimental values. 

SA06 

Interplay between magnetization and polarization in epitaxial 

(Ga,Fe) 2O3 thin films with additional ion-substitutions into Fe sites 

R. H. Shin 1 , J. H. Lee 1 , S. H. Oh 2 , W. Jo 2 *, C. Lefevre 3 , F. Roulland 3 , A. Thomasson 3 , C. 

Meny 3 and N. Viart 3 

1 

Department of Physics and CNRS-EWHA <strong>International</strong> Research Center, Ewha 

Womans University, Korea 

2 

Department of Physics, Ewha Womans University, Korea 

3 

Institute of Physics and Chemistry of Materials of Strasbourg, France 

(Ga,Fe) 2O 3 (GFO) is a promising material for room-temperature multiferroic because of high 

magnetic T C as 370 K when Ga = 0.6 and Fe = 1.4. However, multiferroic properties of GFO 

in thin film type is controversial because most of polarization-electric field hysteresis curves 

in GFO showed leaky behaviors due to large leakage current. In this research, we focused on 

the improved magnetic and electric properties of GFO thin films as multiferroic by decreasing 

their leakage current. The main origin probably lies on electron hopping between Fe 3+ and Fe 2+ 

octahedron sites which can co-exist due to charge neutrality by oxygen vacancy. Therefore, we 

tried to decrease leakage current by substituting Fe 2+ site with divalent cation. The ion-substituted 

GFO thin films were epitaxially deposited along the b-axis by pulsed laser deposition at 750°C 

for 15 min in oxygen partial pressure of 200 mTorr on SrRuO 3/SrTiO 3 (111) substrates. The 

films showed the strongly reduced leakage current up to 5~6 order of magnitude. Magnetic 

properties of the doped GFO thin films were investigated by SQUID measurement. Ferroelectric 

polarization as a function of external field was measured in macroscopic and microscopic 

schemes. Magnetoelectric interactions of the epitaxial thin-films will be addressed in this talk. 

SA07 

Fabrication and characterization of heusler-alloy/perovskite 


Kohei Kobayashi, Keita Sakuma*, Naoto Fukatani, Tetsuya Miyawaki, Kenji Ueda 

and Hidefumi Asano 


Multiferroic heterostructures composed of ferromagnetic half-metal and ferroelectric materials have 

attracted significant interest due to the potential applications for nanoscale devices. Heusler-alloy / 

perovskite heterostructures are expected to emerge the interface magnetoelectric1) and tunnel electroresistance 

effect. In this study, to explore the potential of Heusler-alloy / perovskite heterostructures, we 

have investigated multiferroic and transport properties of heterostructures composed of half-metallic 

Heusler-alloy Fe 2CrSi (FCS) and ferroelectric perovskite Ba 0.7Sr 0.3TiO 3 (BSTO). BSTO was firstly 

deposited on MgO and LaAlO 3 substrates by magnetron sputtering, followed by the deposition of 

FCS at 550-750°C. Structural characterization revealed that FCS grew epitaxially on BSTO with the 

relationship of BSTO(001)[100]||FCS(001)[110]. From M-H curve of the BSTO (100 nm) / FCS 

(150 nm) bilayer, saturated magnetization of 417 emu/cc was obtained. The ferroelectric properties 

of La 0.7Sr 0.3MnO 3 (LSMO) / BSTO (100 nm) / FCS (50 nm) were measured, and the maximum 

remaneant polarization was 73 μC/cm 2 . From these results, ferromagnetic and ferroelectric properties 

were preserved in BSTO/FCS heterostructures. From the analysis of I-V characteristics, Schottkyemission 

was found to be a dominant leakage mechanism in LSMO / BSTO / FCS. The BSTO / FCS 

heterostructure is a promising candidate for fabricating multiferroic devices. 

1) K. Yamauchi et al., Appl. Phys. Lett. 91, 062506 (2007) 

SA08 

SA09 

Preperation of hexagonal YFeO 3 powder and thin film 

Hanju Lee, Kyoungchul Kim, Sujin Lee, Sul A Choi and Kiejin Lee* 

physics, Department of physics, Sogang university, Korea 

SA10 


Optical properties of (SrMnO3) n/(LaMnO3) 2n superlattices: An 

insulator-to-metal transition observed in the absence of disorder 

Andrea Perucchi 1 , Leonetta Baldassarre 1 , Alessandro Nucara 2 , Paolo Calvani2, 

Carolina Adamo 3 , Darrell G Schlom 3 , Pasquale Orgiani 4 , Luigi Maritato 4 and Stefano 

Lupi 5 

1 

Sincrotrone Trieste, Italy 

2 

CNR-SPIN and University of Rome 'Sapienza', Italy 

3 

Cornell University, USA 

4 

CNR-SPIN and University of Salerno, Italy 

5 

CNR-IOM and University of Rome 'Sapienza', Italy 

We measure the optical conductivity, σ 1(ω), of (SrMnO 3) n/(LaMnO 3) 2n superlattices (SL) 

for n=1, 3, 5, and 8 and 10 < T < 400 K. Data show a T-dependent insulator to metal 

transition (IMT) for n=3, driven by the softening of a polaronic mid-infrared band. At 

n=5 that softening is incomplete, while at the largest-period n=8 compound the MIR 

band is independent of T and the SL remains insulating. One can thus first observe the 

IMT in a Manganite system in the absence of the disorder due to chemical doping. 

Unsuccessful reconstruction of the SL optical properties from those of the original bulk 

materials suggests that (SrMnO 3) n/ (LaMnO 3) 2n heterostructures give rise to a novel 

electronic state. 

A. Perucchi et al., Nano Letters 10 (12), 4819-4823 (2010) 

In the past few years, multiferroic materials, characterized by coexistence of two or 

more ferroicity, have attracted much attention due to their interesting properties. Among 

the magnetic ferroelectric materials, there is an important class, hexagonal manganese 

oxides (RMnO 3, R: rare-earth element), which have been extensively studied because 

of its unusual property. However, hexagonal iron oxides (RFeO 3), which have a similar 

structure to RMnO 3, have been rarely reported due to a preferred formation to the 

orthombic or garnet phase. Here, we report that the hexagonal phase can be easily 

prepared as a powder and thin film from chemical solution deposition method (CSD). 

The crystallization temperature, crystal structure, magnetic and electric properties of 

the thin film and powder were investigated. The hexagonal phase was observed at 

750-800, and at higher temperature (>850) orthombic phase appeared. The observed 

structure belonged to the paraelectric P63/mmc phase, rather than ferroelectric phase. 

Samples showed paramagnetic property at room temperature caused by geometrically 

fluctuated magnetism in tri-angular spin lattice. 

Magnetic hysteretic effects in LaAlO 3 /SrTiO 3 Heterostructures 

Veerendra Kumar Guduru 1 , Alix Mccollam 1 , Sander Wenderich 2 , Michelle Kruize 2 , 

Uli Zeitler 1 *, Alexander Brinkman 2 , Jan Kees Maan 1 , Mark Huijben 2 , Hans 

Hilgenkamp 2 , Gertjan Koster 2 , Guus Rijnders 2 and Dave Blank 2 

1 HFML/IMM,Radboud University Nijmegen, Netherlands 

2 MESA+ Institute for Nanotechnology, University of Twente, Netherlands 

A two-dimensional electron system (2DES) with remarkable electronic properties can be 

realized at the interface between two band insulators LaAlO 3 and SrTiO 3 (1). Depending 

on growth conditions, this 2DES has been found to show a superconducting ground state 

(2), magnetic ordering (3) and even co-existence of these two properties (4-5). The origin 

of the magnetic behaviour at the interface is still unclear, and to try to understand it we 

have performed magneto-transport studies on LaAlO 3/SrTiO 3 heterostructures in high 

magnetic fields up to 33 T, and low temperatures down to 0.3 K. We observed negative 

magnetoresistance (nMR) which is nearly identical for all field orientations in the temperature 

range from 4 K to 350 mK. This nMR could be related to reduced spin scattering due to the 

alignment of spins at the interface (3). At low magnetic fields, the nMR is very sensitive to 

temperature and at temperatures below 1 K an unusual time dependent magnetic hysteresis 

appears for field below 3 T. We propose a magnetocaloric effect model to explain the 

hysteretic behaviour, and propose that the possible underlying origin of the hysteresis is the 

co-existence of ferro- and antiferromagnetic phases in the spin system. 

1) A. Ohtomo and H.Y. Hwang, Nature 427, 423, 2004. 2) N. Reyren et al., Science 317, 1196, 2007. 3) A. Brinkman et al., 

Nature Materials 6, 493, 2007. 4) L. Li et al., Nat Phys 7 (10), 762-766, 2011. 5) J.A.Bert et al., Nat Phys 7 (10), 767-771, 2011. 


Poster Friday

Poster Friday 

SA11 


Synthesis and magnetoelectric properties of multiferroic composites on 

the cobalt ferrite - pzt system 

C. Miclea 1 *, L. Amarande 1 , L. Trupina 1 , M. Cioangher 1 , C. T. Miclea 2 and C. F. 

Miclea 1 

1 National Institute for Materials Physics, Bucharest, Romania 

2 Hyperion University, Bucharest, Romania 

In the present study we prepared and investigated the properties of bulk particulate 

composites made from cobalt ferrite (COF) and a soft piezoelectric material (PZT). 

We chose COF and soft PZT due to their high magnetic and piezoelectric parameters 

respectively. Composite samples, according to the formula xCOF(1-x)PZT with 0 ≤ x ≤ 

1 were prepared by mixing the COF and PZT powders, pressing them as discs and then 

sintered at 1200 C for 3 hours. Structural, magnetic, piezoelectric and magnetoelectric 

characteristics of the sintered composites were then determined as a function of the 

weight fraction of COF into PZT and magnetic fields. The ME coefficient shows a 

maximum value about 70 mV/cmOe for composites containing 40 % COF and 60% 

PZT, in a DC magnetic field of 3 kOe at a frequency of 1KHz of the ac magnetic field. 

Some of the dielectric and piezoelectric properties of the composite samples, as a 

function of the weight fraction x, were also determined. The results were discussed in 

terms of the recent theoretical cube model of different connectivities of particles of one 

phase embedded into the matrix of the second phase. 

SA12 

Detailed structural study of BiFeO 3/SrRuO 3 heteroestructures grown 

on SrTiO 3 (001) substrates 

Claribel Dominguez 1 , John Edward Ordonez 1 , Maria Elena Gomez 1 , Wilson Lopera 1 and Pedro Prieto 2 

1 Thin Film Group, Department of Physics, Universidad del Valle, A.A. 25360, Cali, Colombia, Colombia 

2 Center of Excellence for Novel Material CENM, Calle 13 # 100-00 320-1026, Cali, Colombia, Colombia 

SA13 

WITHDRAWN 

Lattice engineering on transition metal oxide thin film 

Chang Uk Jung* 


MOVED 


SA14 

Magnetisation in different multiferroic YMO (Yttrium Manganese 

Oxide) thin films 

Manish Kumar*, R.j. Choudhary and D.m Phase 

UGC-DAE CSR, UGC-DAE CSR Indore,Madhya Pradesh, India 

Recently Yttrium manganese oxides (YMO): hexagonal YMnO 3 and orthorhombic 

YMn 2O 5 have attracted considerable attention as both of these compounds exhibit 

multiferrocity but the microscopic origins are different. Here we stabilize thin films of 

different phases of YMO by pulsed laser deposition from a single h-YMnO 3 target and 

characterize them with various techniques and perform magnetization measurements. 

It is observed that the phase stability and crystallinity of YMO thin films depend on 

the substrate used and oxygen partial pressure (OPP). Oriented and polycrystalline 

growth of h-YMnO 3 and O-YMn 2O 5 phase film are observed on different substrates. 

ZFC,FC (Magnetisation verses Temperature ) and MH magnetization measurements 

of these multiferroic films were performed. All the multiferroic thin films show 

the antiferromagnetic transition in ZFC measurements which is forbidden in FC 

measurements. MH behavior at both sides of magnetic transitition is in good agreement 

in these multiferroic thin films. 

1. Bas B. Van Aken, Thomas T. M. Palstra, Alessio Filippetti and Nicola A. Spaldin,Nature 

Materials,Vol 3, 2004, pp.164-170 2 L. C. Chapon, P. G. Radaelli, G. R. Blake, S. Park and S.W. 

Cheong, Phys.Rev.Letter 96, 097601 (2006) 3. W. Prellier, M P Singh and P Murugavel, J. Phys.: 

Condens. Matter 17 (2005) R803-R832 4. A Munoz et al 2002 J. Phys.: Condens. Matter 14 3285 

SA15 

Dependence of magnetoelectric response on magnetostrictive content 

in composite multiferroics 

Mohsin Rafique 1 *, Syed Qamar Ul Hassan 1 , Muhammad Saifullah Awan 2 and Sadia 

Manzoor 1 

1 

Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan, 

Pakistan 

2 

Center for Nano and Micro Devices (CNMD), COMSATS Institute of Information 

Technology, Islamabad, Pakistan, Pakistan 

Magnetoelectric multiferroics exhibit a strong coupling between ferromagnetic and ferroelectric 

ordering. The coupling between these two types of orderings may occur naturally or be mediated via 

mechanically. This coupling is very weak in single phase multiferroics. The design and investigation 

of composites of magnetostrictive and piezoelectric phases have shown magnetoelectric coupling 

orders of magnitude higher than that of single phase multiferroics. The mechanical deformation 

in magnetostrictive and piezoelectric phases results in the coupling between the two constituents. 

The multiferroic CoFe 2O 4-BaTiO 3 (CFO-BTO) composites with nanoscale mixture of the two 

constituents were prepared by solgel process. Four different compositions, with varying percentage 

of constituents, were investigated. X-ray diffraction revealed the coexistence of the two phases. 

Magnetic properties of the CFO-BTO nanocomposites were examined which were consistent with 

the composition. The magnetoelectric coupling between CFO and BTO was demonstrated by an 

external magnetic field induced change in capacitance. The magnetoelectric coupling was found to 

be not only dependent on the applied magnetic field but also on the composition of the composites. 

It has a nonlinear dependence on magnetostrictive content. 

SA16 

Raman analyses of oxygen defects in hexagonal HoMnO 3 thin films 

Xiang-bai Chen 1 , Nguyen Thi Minh Hien 2 , D. Lee 3 , T. W. Noh 3 and In-sang Yang 2 

1 Konkuk University, Korea 

2 Ewha Womans University, Korea 

3 Seoul National University, Korea 

Oxygen defects are usually unavoidable in synthesizing oxide thin films. In this study, 

we investigated the origins of the oxygen defects in hexagonal manganites HoMnO 3 

epitaxial thin films through Raman spectroscopy. We found that the oxygen defects in 

hexagonal HoMnO 3 thin films have different effects on different phonon modes and 

on magnon scattering. Our analyses indicated that the oxygen defects in hexagonal 

HoMnO 3 thin films would be mainly correlated with the basal O 3 and/or O 4 oxygen 

ions. Furthermore, our analyses of oxygen defects predicted that the Mn 3d orbitals 

would be more strongly hybridized with the apical O 1 and/or O 2 2p orbitals than the 

basal O 3 and/or O 4 2p orbitals. This prediction is consistent with our resonant Raman 

scattering study and earlier first-principle calculations of electronic structures of 

hexagonal manganites.

SA17 

Preparation and properties of inverse perovskite Mn 3GaN thin films 

Hiroki Tashiro, Ryosuke Suzuki*, Tetsuya Miyawaki, Kenji Ueda and Hidefumi 

Asano 

Department of engineering, Nagoya University, Japan 

There has been considerable interest in antiperovskite Mn 3GaN because of its intriguing 

physical properties such as negative thermal expansion, magneto-volume effect and 

piezomagnetic effect(1). Mn 3GaN is expected to be advantageous to fabricate thin-film 

hybrid devices with various perovskite oxides, since it has a cubic antiperovskite structure 

virtually identical with the perovskite oxides. However, there is no report on growth 

of Mn 3GaN thin films and heterostructures. In this paper, we report on the preparation 

and properties of Mn 3GaN thin films as well as ferroelectric Ba 0.7Sr 0.3TiO 3/Mn 3GaN 

heterostructutes. Mn 3GaN films were deposited on (001) SrTiO 3 and LaAlO 3 substrates at 

450~650°C by ion beam sputtering of a sintered stoichiometric target. Ba 0.7Sr 0.3TiO 3films 

were prepared at 650~750°C by magnetron sputtering. In-plane and out-of-plane 

X-ray diffraction analysis revealed that on SrTiO 3 substrate Mn 3GaN films were grown 

coherently with the in-plane lattice parameter aMGN of 0.3903 nm. On LaAlO 3 substrate 

a Ba 0.7Sr 0.3TiO 3 layer and subsequently a Mn 3GaN layer were grown epitaxially with the 

relationship of LaAlO 3(001)[100]//Ba 0.7Sr 0.3TiO 3(001)[100]//Mn 3GaN (001)[100]. These 

Mn 3GaN thin films showed a metallic temperature dependence of resistivity with 0.8-0.9 

mΩcm at room temperature. It was found that the Ba 0.7Sr 0.3TiO 3/Mn 3GaN heterostructutes 

exhibited a colossal magnetocapacitance effect. 

(4) P. Lukashev, et al., Phys. Rev. B 78 184414 (2008) 

SA18 

Ferroelectric and magnetic properties of BiMnO 3 thin films 

Min-hwa Jung and Yoon-hee Jeong* 


BiMnO 3 is heralded widely as a rare case of multiferroicity with simultaneous 

existence of both ferroelectricity and ferromagnetism. Ferroelectricity in BiMnO 3, 

however, still remains controversial as various results do not converge on a definite 

conclusion [1-3]. In order to shed light on this issue, we have synthesized BiMnO 3 

thin films on Nb:SrTiO 3 substrates by PLD method. Measurements of various physical 

properties such as dielectric properties, PE hysteresis loop, and piezoelectric d33 do 

not show any significant evidence of ferroelectricity for all films. Thus, we are led to 

conclude that BiMnO 3 is not ferroelectric in accordance with a theoretical calculation 

[4-5]. Also of interest is the ferromagnetism of BiMnO 3 and, in particular, its magnetic 

easy direction. We also investigate the magnetic properties of the films with in and out 

of the plane orientations. From these measurements, the magnetic easy direction is 

inferred for the monoclinic phase BiMnO 3. In conclusion, the present study offers a full 

characterization of the ferroelectric and magnetic properties of multiferroic BiMnO 3. 

[1] T. Kimura, S. Kawamoto, I. Yamada, M. Azuma, M. Takano, and Y. Tokura, Phys. Rev. B 67, 

180401 (2003) [2] M. Grizalez, E. Martinez, J. Caicedo, et al.,, Microelectronics Journal 39, 1308 

(2008) [3] A. A. Belik, S. likubo, T. Yokosawa, et al., J. Am. Chem. Soc. 129.971 (2007) [4] A.J. Hatt 

and N.A. Spaldin, Eur. Phys. J. B 71,435 (2009) [5] Shichidou T, Oguchi T (2006) Multiferroicity of 

BiMnO3 reexamined from first principles. Presented at APS meeting March Meeting, Baltimore, MD. 

SA19 

Ferroelectric polarization induced magnetic anisotropy in Co40Fe40B20/ YMnO3 multiferroic heterostructure 

Jiawei Wang 1 , Yanggang Zhao 1 *, Peisen Li 1 , Sen Zhang 1 , Syed Rizwan 2 , Xiufeng 

Han 2 , Xuefeng Sun 3 , Yuanjun Yang 4 , Qianping Chen 1 and Xin Zhang 1 

1 

Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua 

University, China 

2 

Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, China 

3 

Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and 

Technology of China, China 

4 

National Synchrotron Radiation Laboratory, University of Science and Technology of China, China 

Multiferroic (MF) materials have attracted much attention due to their interesting new physics and potential 

for exploring novel multifunctional devices. The research of magnetic anisotropy in MF heterostucture is an 

important aspect. One of the key issues in the MF heterostructures is the effect of ferroelectric (FE) polarization on 

magnetic anisotropy. So far, however, a lot of work has been carried out on MF heterostructures with crystalline 

ferromagnetic films. Actually, MF heterostructures involving amorphous ferromagnetic materials are also very 

interesting due to the absence of magnetocrystalline anisotropy and low coercive force Hc. We have studied the 

coupling between amorphous magnetic Co 40Fe 40B 20 (CFB) and YMnO 3 (YMO) in the heterostructure with CFB 

film grown on YMO (110) substrates. A large uniaxial magnetic anisotropy (UMA) was observed from room 

temperature to 10 K with magnetic easy axis (MEA) along the polarization direction of YMO. More interestingly, 

the angular dependence of coercive force Hc shows a non-monotonous behavior. The results were discussed 

by considering the coupling between the FE domain in YMO and magnetism in CFB. This work is helpful for 

understanding the effect of FE polarization on magnetic anisotropy in MF heterostuctures. 

SA20 

SA21 

SA22 


Ferroelectric-domain-switching controlled magnetism in CoFeB/PMN- 

PT multiferroic heterostructure 

Peisen Li 1 , Yonggang Zhao 1 *, Sen Zhang 1 , Lifeng Yang 1 , Syed Rizwan 2 , Qianping 

Chen 1 , Jiawei Wang 1 and Xiufeng Han 2 

1 

Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, 

Tsinghua University, China 

2 

Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, China 

Multiferroic materials have attracted much attention due to their interesting new physics and potential 

applications in new multifunctional devices. In multiferroic materials, the magnetization can be tuned by 

electric fields, which open a new way to reach high integration density and low power consumption in 

information storage. In the shorter term, niche applications are more likely to emerge in the two-phase 

systems [1], so there have been lots of work on the electric-field control of magnetism via the piezostrain 

in ferromagnet-ferroelectric heterostructures[2, 3]. However, the reports related to magnetoelectric 

(ME) effect via ferroelectric domain switching are still limited. Thus, we have studied the electric-field 

control of magnetism in Co 20Fe 40B 20/Pb(Mg 1/3Nb 2/3) 0.7Ti 0.3O 3(PMN-PT)(001) two-phase-system. Nonvolatile 

and volatile changes of magnetization related to different types of ferroelectric domain switching 

were found and the ratio between them changes with temperature. The angular-dependence of electricfield 

control of magnetism indicates that some magnetic domains rotate 90°, which is consistent with 

our in situ electric-field-dependent magnetic force microscopy data. The results were explained by 

considering the ferroelectric domain switching induced magnetic anisotropy. This work is helpful for 

understanding the coupling between magnetism and ferroelectric domain switching. 

[1] W. Eerenstein et al., Nature 442, 759 (2006). [2] C. Thiele et al., Phys. Rev. B 75, 054408 (2007). 

[3] J. J. Yang et al., Appl. Phys. Lett. 94, 212504 (2009). 

Multiferroic properties of BaTiO 3 - Zn 1-xCo xO multilayer thin films 

Anuraj S 1 , Shivaraman Ramaswamy 1 *, Helen Annal Therese 1 , C Gopalakrishnan 1 and 

A Karthigeyan 2 

1 Nanotechnology Research Center, SRM University, India 

2 Department of Physics and Nanotechnology, SRM University, India 

Near room temperature ferroelectric and ferromagnetic hysteresis is observed 

in horizontal superlattice system of BaTiO 3 - Zn 1-xCo xO (x > 0.2) [BTO - ZCO] 

multilayered thin films. The multilayered thin films were prepared on Si substrate 

by alternate deposition of BTO and ZCO layers to a thickness of 350 nm using 

pulsed laser deposition technique. Analysis of the prepared thin film by x-ray powder 

diffraction and electron microscopic techniques confirm the polycrystalline nature 

of the multilayered film. Dielectric and the magnetic properties studied on the 

multilayered thin film at different temperatures exemplified the coupling between their 

dual order parameters and it is mediated through an electric field effect at the interface. 

1. Multiferroic properties of Bi0.8La0.2FeO3/CoFe2O4 multilayer thin films. Shan-Tao Zhang, Yi 

Zhang, Zhen-Lin Luo, Ming-Hui Lu, Zheng-Bin Gu, Yan-Feng Chen., Applied Surface Science 255 

(2009) 5092-5095. 2. Multiferroic BaTiO3-CoFe2O4 Nanostructures., H. Zheng, J. Wang, S. E. 

Lofland, Z. Ma, L. Mohaddes-Ardabili, T. Zhao, L. Salamanca-Riba, S. R. Shinde, S. B. Ogale, F. 

Bai, D. Viehland, Y. Jia, D. G. Schlom, M. Wuttig, A. Roytburd, R. Ramesh. Science 303, (2004) 661. 

Study of structural phase transition and multiferroic properties of 

Samarium substituted BiFeO 3 thin films 

Mahdiyar Bagheri, Shivaraman Ramaswamy*, Helen Annal Therese and C 

Gopalakrishnan 


In this study we report the effect of samarium substitution on the structure and 

multiferroic properties of BiFeO 3 thin films. The Bi 1-xSm xFeO 3 thin films of various 

thicknesses were sputter deposited on to Si substrates. Magnetic and electric properties 

of the thin films were studied by vibrating sample magnetometer, impedance analyzer 

and I-V characterizer. Samarium substitution-driven structural phase transition was 

studied by x-ray diffraction at room temperature. Samarium doping was found to 

modify structural properties of Bi 1-xSm xFeO 3 thin film. The phase transition was found 

to destruct cycloid spin structure of BiFeO 3 that resulted in amplified magnetoelectric 

interactions. The substitution of Sm was found to be a promising way to control the 

conductivity and leakage current of film by suppressing the formation of oxygen 

vacancies. 

1. Hiroshi Uchida, Risako Ueno, Hiroshi Funakubo, and Seiichiro Koda, J. Appl. Phys.100, 014106 

(2006) 2. E. Ohshima, Y. Saya, M. Nantoh and M. Kawai Solid State Commun. 116 (2000), p.73. 


Poster Friday

Poster Friday 

SA23 


Study of ferroelectricity in Eu substituted BiMnO 3 films 

Shivaraman Ramaswamy*, Helen Annal Therese and C Gopalakrishnan 


In this paper, we report evidence of ferroelectricity in europium substituted manganite 

(Bi 1-xEu xMnO 3) thin films synthesized via sol gel synthesis and dip coating method 

on a single-crystal (1 0 0) substrates. The films were post treated by annealing at 

500°C. X-ray diffraction measurements were used to analyze the crystal structure 

and phase purity of the thin films. AFM measurements were performed to investigate 

surface morphology; quantitative values of roughness and grain size which are in the 

range between 30 and 150 nm. Ferroelectric characterization was conducted at low 

temperatures and at 300 K. Hysteresis loops (polarization vs. voltage) were obtained, 

showing enhanced ferroelectricity at room temperature in the 10% Eu substituted 

BiMnO 3 film. Resistance vs. temperature measurements were performed, which 

indicated this to be very robust insulating material. Moreover, all films show small 

dielectric dispersion and dielectric loss. 

SA24 

Experimental evidence for Exchange bias in polycristalline BiFeO 3 / 

Ni 81Fe 19 

Tony Hauguel, Souren P Pogossian, David Toyo Dekadjevi*, Jean-philippe Jay, 

Mikhail Indenbom, David Spenato and Jamal Ben Youssef 

Laboratoire de Magnetisme de Bretagne, CNRS-Universite Europeene de Bretagne, 

France 

Multiferroic (MF) materials have been the subject of extensive studies in the past decade since it 

allows a coupling of ferroelectric and magnetic orders in a single phase. Among all the multiferroic 

materials studied so far, BiFeO 3 (BFO) exhibits the coexistence of ferroelectric and antiferromagnetic 

orders at room temperature. Magnetic heterostructures with a ferromagnetic thin film exchange 

biased to an antiferromagnetic-BFO film may allow an electric field influence on the magnetic 

hysteresis properties of the bilayer. The exchange coupling and exchange bias involving MF/ 

F systems has previously been obtained with either epitaxial BFO [1] or BFO bulk materials [2]. 

However, the exchange coupling between a ferromagnetic film and a polycrystalline multiferroic was 

not studied. Furthermore, previous studies have shown that polycrystalline BFO exhibits multiferroic 

properties. We report experimental evidence for exchange bias in polycrystalline BiFeO 3/Ni 81Fe 19 

bilayers, grown by RF sputtering [3]. Our measured 17 Oe shift corresponds to exchange energy per 

unit area of interface coupling the two films of 11×10 -3 erg/cm 2 comparable with similar epitaxial 

grown systems. The azimuthal behavior of longitudinal and transverse components of magnetization 

reveals the presence of induced unidirectional and biquadratic anisotropies. 

[1] H. Bea et al., Phys. Rev. Lett. 100, 017204 (2008) [2] J. Dho et al., J. Appl. Phys. 106, 073914 

(2009) [3] T. Hauguel et al., J. Appl. Phys. 110, 073906 (2011). 

SB01 

Parit variation in the rectangular array of periodic holes on 

superconducting thin film 

Kamran Muhammad 1 * and Qiu Xiang Gang 2 

1 Physics, COMSATS Institute of IT, Islamabad, Pakistan 

2 Institute of Physics, Chinese Academy of Sciences, Beijing, China 

Superconductivity has been full of surprises and wonder. One of the most elegant 

properties of superconductors is the quantization of magnetic flux in units of φ0=h/2e, 

where h is the Planck constant of quantum mechanics, and 2e the electron-pair charge 

serving the fundamental building block of the superconducting condensate. Here we 

report our discovery of a new twist of this phenomenon in a film geometry perforated 

with a periodic lattice of sub-micron holes, a variation of the flux quantization based on 

the parity of the number of the flux quanta. Measured in terms of magneto-resistance 

at temperatures just below the transition temperature of the bulk superconductor, we 

find that superconductivity is most enhanced at odd multiples of the flux quantum. 

We explain the phenomenon by noting that thermal quasi-particles, which see the 

superconducting flux quantum only as half, are in fact suppressed at these flux values. 

In fields larger than the thermodynamic critical field, where quasi-particles dominate, 

magneto-resistance minima only occur at such odd values. 


SB02 

Charge disproportion, spin and orbital states in the tri-layered 

nickelate La 4Ni 3O 8 from first principles 

Hua Wu* 

Department of Physics, Fudan University, Shanghai, China 

Several mixed-valent layered nickelates were synthesized very recently [1,2], in 

the effort to search an analog to the hole doped cuprates. Here we have studied 

the electronic structure and the magnetism of the tri-layered La 4Ni 3O 8, using the 

configuration-state constrained LDA+U calculations. Our results show that La 4Ni 3O 8 

would be a charge homogeneous low-spin half metal in the ferromagnetic state. In 

contrast, the C-type antiferromagnetic state is insulating and has a charge disproportion 

of the formal 2Ni + /Ni 2+ type, thus accounting for several experimental observations. 

The high-spin (S=1) Ni 2+ state and its orbital configuration are found to be against 

the crystal-field level picture. We note that it would be interesting to explore, for 

novel magnetism and superconductivity, the Ni 2+ low-spin S=0 state and the partially 

occupied x 2-y 2 band structure of the Ni + /Ni 2+ mixed-valent nickelate. 

[1] V. V. Poltavets et al., Phys. Rev. Lett. 104, 206403 (2010). [2] V. V. Poltavets, M. Greenblatt, G. H. 

Fecher, and C. Felser, Phys. Rev. Lett. 102, 046405 (2009). 

SB03 

Carrier doping to the novel layered nickelate 

Yoshiki Sakurai, Yoshihide Kimishima and Masatomo Uehara* 

Yokohama national university, Japan 

Recently a series of new layered nickelate (Ln n+1Ni nO 2n+2) (Ln=La, Nd) has been 

synthesized with using CaH 2 as a reducing agent or hydrogen gas. The crystal structure 

is the analogue of so-called Ruddlesden-Popper phase, and basically the same crystal 

structure with high-Tc superconducting cuprate, consisting of insulating block layer 

and two-dimensional NiO 2 layer. Interestingly Ni ions in these materials can have the 

same electronic configuration with Cu 2+ 3d 9 in high-Tc cuprate, suggesting that this is a 

promising candidate for another high-Tc material. Therefore, we have tried to carrierdope 

to Ln and Ni sites of (Ln n+1Ni nO 2n+2) (Ln=La, Nd) with n=2, 3, and ∞ using 

Ca, Cu, Co ions in order to tune the electronic state of Ni. If the Ni electronic state 

is adjusted to 3d 9.15 or 3d 8.85 which are the same cases with those of optimum doping 

level for the emergence of high-Tc in cuprate. We will present the detailed result in the 


SB04 

Occurrence of superconductivity and structural variations in the Sr 1-xT 2- 

2xGe 2 layer system (T = Ni, Pd, and Pt; x ≥ 0) 

H. C. Ku 1 , I. A. Chen 1 , C. H. Hung 1 , C. Y. Lin 1 , S. J. Wang 1 , Y. B. You 1 , M. F. Tai 1 and 

Y. Y. Hsu 2 


2 Department of Physics, National Taiwan Normal University, Taiwan 

Superconducting transition temperature Tc of the body-centered-tetragonal (bct) 

122 Sr(Ni 1-yPdy) 2Ge 2 (0 ≤ y ≤ 1) layer system (space group I4/mmm) increases 

monotonically from 0.87 K for 3d-Ni SrNi 2Ge2 to 3.12 K for 4d-Pd SrPd 2Ge 2. 

However, due to larger atomic radius of 5d-Pt, the bct stoichiometric Sr(Pd 1-yPty) 2Ge 2 

phase (I4/mmm) is unstable and a structural transformation to a vacancy stabilized 

superstructure Sr 1-x(Pd 1-yPty) 2-2xGe 2 with orthorhombic space group Pmna may be 

formed. Trace of superconductivity with Tc ranging from 5-10 K in the Sr 1-xPt 2-2xGe 2 

system was observed but very difficult to be stablized. This structural transformation 

is very similar to the high temperature superconducting system K 1-xFe 2-2xSe 2 with I4/ 

mmm and two superstructure space groups Pmna and I4/m, where superconductivity 

Tc up to 32 K was reported only in the bct I4/m system. This work was supported by 

Grant No. NSC98-2112-M-007-013-MY3 of National Science Council of Republic of 

China.

SB05 

Fermi surface study on the rattling-induced superconductor KOs2O6 Taichi Terashima 1 *, Nobuyuki Kurita 1 , Andhika Kiswandhi 2 , Eun-sang Choi 2 , James S. 

Brooks 2 , Kota Sato 3 , Jun-ichi Yamaura 3 , Zenji Hiroi 3 , Hisatomo Harima 4 and Shinya 

Uji 1 

1 


2 

National High Magnetic Field Laboratory, USA 

3 

ISSP, Univ. of Tokyo, Japan 

4 

Graduate School of Scienece, Kobe Univ., Japan 

SB06 

Transient analysis of the current density and temperature distribution 

of the MgB2 superconductor in the He atmosphere 

H. M. Iftekhar Jaim 1 and Klaus Barner 2 

1 

Department of Mechanical, Material and Aerospace Engineering, University of 

Central Florida, USA 

2 

Department of Physics (4 Physik),, University of Gottingen, F. Hund Platz 1, 37077 

Gottingen, Germany 

SB07 

WITHDRAWN 

In this paper, the transient analysis is carried out for the type II superconductor material 

MgB 2 in liquid Helium atmosphere. The strong nonlinearity of the E-J relationship 

near critical current poses a challenge in such calculations for getting practical values 

in other models employed for Ohmic materials. For this reason, the curl-curl equation 

and the variable magnetic field quantity are employed as the unknown in solving the 

PDE by the finite element method. The temperature distribution by the generated heat 

in the superconductor is calculated by the coupled conduction and convection module. 

Using the nominal experimental values for the exponential current fundamental 

characteristics like the magnetic flux, current distribution density and temperature 

profile in the superconductor are calculated for 2D axis symmetric cylindrical cases. 

The study gives the limiting current values to avoid heat generation and shows the 

development of the mixed state and finally the normal state with the time. Effect of 

changing the magnitude of current and time constant is also studied. Ripple effect at the 

surface is observed due to difference in the inner and outer magnetic flux distribution. 

Meissner-like effect on normal- superfluid interface of imbalanced 

Fermi gas 

Neda Ebrahimian* and Mohammad Mehrafarin 

Physics Department, Amirkabir University of Technology,Tehran 15914, Iran 

The observation of phase separation between the superfluid (SF) core and a normal (N) shell around 

the core in ultra-cold Fermi gases has been reported by the new experiments of MIT and Rice 

groups[1-2]. Much researches have been done about the N-SF interface[3-5]. In this article, we 

examine the N-SF interface of a imbalanced Fermi gas with two spin species, in the presence of a 

weak magnetic field. In our analysis, we consider a constant magnetic field in the N side and anticipate 

the possibility of the Meissner-like effect in the SF side. We take into account the various scattering 

regions of the BCS regime and analytically obtain the transmission coefficients by using the perturbed 

Bogoliubov equations. It suffices to remark that the leading order term in transmission coefficients are 

independent of the energy of incident quasiparticles. Then, we calculate the heat conductivity across 

the interface at sufficiently low temperatures. We describe how the heat conductivity is affected by the 

Meissner effect and the species imbalance. Also the relation between the additional heat conductivity 

and penetration depth is obtained. The corresponding graphs is also plotted and discussed. 

Furthermore, we show the dependence of the heat conductivity on average chemical potential. 

References: [1] G. B. Partridge, W. Li, R. I. Kamar, Y. A. Liao, and R. G. Hulet, Science 311, 503 (2006). [2] M. 

W. Zwerlein, A. Schirotzek, C. H. Schunck, and W. Ketterle, Science 311, 492 (2006). [3] B. Van Schaeybroeck 

and A. Lazarides, Phys. Rev. Lett. 98, 170402 (2007). [4] N. Ebrahimian, M. Mehrafarin, and R. Afzali, 

Physica B 407, 140 (2012). [5] N. Ebrahimian, M. Mehrafarin, and R. Afzali, To be published Physica C: 

Superconductivity (2012). 

SB08 

SB09 

SB10 


Magnetic properties and structure evolution along R 2RhIn 8 series 

Petr Cermak 1 *, Marie Kratochvilova 1 , Jan Prokleska 1 , Marie-helene Lemee-cailleau 2 , 

Bachir Ouladdiaf 2 and Pavel Javorsky 1 

1 Department of Condensed Matter Physics, Charles University in Prague, Czech 

Republic 

2 Institut Laue-Langevin, France 

Intermetallic compounds R 2RhIn 8 (R = rare earth) are structurally related to a class of Ce-based 

heavy-fermion superconductors. Study of their magnetic structure and behavior is important for 

understanding mechanism of the unconventional heavy-fermion superconductivity. We have 

successfully grown single crystals of these compounds with R = Nd, Tb, Dy, Ho, Er and Tm 

from the melt in the In flux. We report the evolution of the magnetic properties of this series. All 

studied compounds exhibit antiferromagnetic behavior with the Neel temperatures up to 43 K 

for Tb compound. Magnetization and specific heat measurements have revealed metamagnetic 

transitions to another antiferromagnetic phase for Tb, Dy and Ho compounds. We show detailed 

magnetic phase diagrams for all these compounds and compare with results reported for 

Nd 2RhIn 8 [1]. Low temperature magnetic structures were studied by neutron diffraction at the 

Institute Laue-Langevin on VIVALDI Laue diffractometer and four-circle D 10 diffractometer. 

From these experiments, propagation vector k = (1/2, 1/2, 1/2) and magnetic structure of studied 

compounds were determined. We present comparison of our results with the magnetic structure 

of Ce 2RhIn 8 and other isostructural compounds from RRhIn5 [2] and R 2CoGa 8 [3] series. 

[1] J. G. S. Duquea, et al., J. Magn. Magn. Mater. 323 (2011) 954-956 [2] N. V. Hieu, et al., J. Phys. 

Soc. Japan 75 (2006) 074708 [3] D. A. Joshi Phys. Rev. B 77 (2008) 174420 

Second magnetization peak and magnetic field distribution in 

superconductor 

Denis Gokhfeld 

L.V. Kirensky Institute of Physics, Russia 

The peak effect on M-H loop of superconductors is analyzed within the framework 

of the extended critical state model (ECSM) [D. M. Gokhfeld, D. A. Balaev, S. I. 

Popkov, K. A. Shaykhutdinov, M. I. Petrov, Physica C 434, 135 (2006)]. The second 

magnetization peak is referred to the vortex lattice transition or the normal phase rise 

occurred at a certain magnetic field value. According to ECSM, these processes extend 

from the surface of a sample (or a granule) to inside due to the magnetic field gradient. 

Any experimental M-H loops are fitted by assigning the appropriate distribution 

of the magnetic field in the sample and the field dependence of the critical current 

density. ECSM predicts that the asymmetry of M-H loop produces the mismatch of the 

peak positions in the field increasing and decreasing branches. The peak in the field 

increasing cycle is situated at lower H value than one in the field decreasing cycle. 

Superconductivity in LuGe2 single crystals 

N. H. Sung 1 , A. I. Coldea 2 , S. K. Choi 2 , H. Kim 3,4 , R. Prozorov 3,4 , and B. K. Cho 1,5 * 

1 

School of Materials Science and Engineering, Gwangju Institute of Science and 

Technology (GIST), Gwangju 500-712, Korea 

2 

Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 

3PU, United Kingdom 

3 

The Ames Laboratory, Ames, Iowa 50011, USA 

4 

Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, 

USA 

5 

Department of Photonics and Applied Physics, Gwangju Institute of Science and 

Technology (GIST), Gwangju 500-712, Korea 

Superconducting binary germanide LuGe 2 single crystals were synthesized using a 

high-temperature metal flux method. Several shiny plate-like single crystals were 

obtained and the compound has the orthorhombic ZrSi 2-type structure (a = 3.9817 Å, b 

= 15.5573 Å, c = 3.8477 Å). Superconducting phase transition temperature at T c = 2.35 

K was confirmed by temperature- and magnetic-field-dependent magnetization, and 

electrical resistivity measurement. In addition, we observed anomalous phase transition 

at around T = 4 K, and confirmed the conventional superconductivity by heat capacity 

measurement. Including these results, we will discuss the nature of LuGe 2 single 

crystals in detail. 


Poster Friday

Poster Friday 

SB11 


Mutual interplay of magnon BEC and superconductivity 

Zygmunt Bak* 

Institute of Physics, Institute of Physics, Jan Dlugosz University, Czestochowa, 

Poland, Poland 

We present a theoretical study of the mutual interplay of magnon Bose-Einstein 

condensate and superconductivity /SC/, provided that they are simultaneously present. 

As a rule these phenomena are treated separately but it is evident that , at least in the 

case of triplet SC, there arises coherence in the electron as well as in the magnetic 

system. Therefore it is reasonable to assess whether magnon BEC can facilitate 

transition to the superconducting state. Such situation should arise when the electron 

pairing arises due to the magnetic interactions . In this case electron pair is accompanied 

by a cloud of magnons and below critical temperature there arises composed electronmagnon 

condensate. We point out that there are experimental evidences that magnetic 

coherence reduces or even switches off the destructive effect of magnetic excitations 

on SC. We prove that in the case of triplet superconductivity there should appear the 

quadrupolar coherence and what’s more quadrupolar interactions contribute to the 

electron pairing. We give arguments that Josephson tunneling and “second sound” 

experiments in magnon and electron condenstes with various junction and setups can 

serve as a cross-tests verifying/falsifying hypothesis that in some systems SC is based 

on magnetic interactions. 

SB12 

Studies of the absolute value of $lambda$ in unconventional 


Jeehoon Kim*, Filip Ronning, N. Haberkorn, L. Civale, J. D. Thompson and Roman 

Movshovich 


The superconducting coherence length ($\xi$), magnetic penetration depth ($\lambda$), and 

their anisotropy are fundamental parameters that characterize superconducting materials. The 

value of $\xi$ can be estimated from the superconducting upper critical field ($H_{c2}$) 

using the Ginzburg-Landau theory. In contrast to $\xi$, precise determination of the absolute 

$\lambda$ value is notoriously difficult. In this talk we present a simple, robust, and modelindependent 

technique to measure $\lambda$ using magnetic force microscopy (MFM), 

and discuss our recent results of the measurements of the absolute value of $lambda$ in a 

variety of unconventional superconductors, such as MgB 2, borocarbides, and pnictides. In 

MgB 2 we will discuss the influence of the intra-band contributions on the superconducting 

properties and scattering effect between the two bands. In a recently discovered Ca 10(Pt 3As 8) 

[(Fe 1-xPt x) 2As 2] 5 (x=0.097) single crystal, we observed large $\lambda$. Large $\lambda$ and 

high anisotropy in this system enhance thermal fluctuation, which leads to a liquid vortex 

phase in this low-temperature (T$_c$= 11 K) superconductor. Also, we will discuss the effect 

of irradiation on the value of $\lambda$ in Ca 0.5Na 0.5Fe 2As 2. Finally, we will present our 

results on the anisotropy of $\lambda$ in a pnictide Ba-122 system, which shows a different 

temperature dependence from that of H$_{c2}$. 

SB13 

Self-consistent calculations of the effects of disorder in d- and s-wave 


Long He and Yun Song* 

Department of Physics, Beijing Normal University, China 

The kernel polynomial method (KPM) [1], as an approach for deriving highly accurate 

spectral properties of large sparse matrices, is very suitable for the numerical study 

on the Anderson localization problem. We investigate the effects of disorder in the 

two-dimensional inhomogeneous superconductors within the KPM by solving selfconsistently 

the Bogoliubov-de Gennes equations [2, 3]. Comparing the behaviors 

of optical conductivity and the time evolutions of single particle Green’s function in 

superconducting phases with different pairing symmetries, we find that the delocalized 

screening effect on the localized quasiparticle states is sufficiently larger in the d-wave 

superconductor than that in the s-wave superconductor. Within a considerable large 

range of disorder strength, the disorder-induced pseudogap state is derived close to the 

s-wave superconductor-insulator transition. 

[1] A. Weisse, G. Wellein, A. Alvermann, and H. Fehske, Rev. Mod. Phys. 78, 275 (2006). [2] L. 

Covaci, F. M. Peeters, and M. Berciu, Phys. Rev. Lett. 105, 167006 (2010). [3] Y. Nagai, Y. Ota, and 

M. Machida, J. Phys. Soc. Jpn. 81, 024710 (2012). 


SB14 

Superconductivity and structural transition of RPt 2Si 2 ( R = Y, La, Lu ) 

Yutaro Nagano 1 *, Nobutaka Araoka 1 , Akihiro Mitsuda 1 , Hirofumi Wada 1 , Masaki 

Ichihara 2 , Masahiko Isobe 2 and Yutaka Ueda 2 



The RPt 2Si 2 compounds, where R stands for a rare-earth element, have a tetragonal 

CaBe 2Ge 2-type structure. LaPt 2Si 2 and YPt 2Si 2 are superconductors with Tc~2 

K[1]. On the other hand, the compounds with R = La and Pr show anomalies in the 

temperature dependence of electrical resistivity[2,3]. These compounds are metallic 

but the resistivity shows a step at T* ~ 110 K, which is attributable to a charge density 

wave (CDW) transition. In order to detect a periodic lattice distortion due to CDW, 

we performed selected area electron diffraction (SAED) and X-ray diffraction (XRD) 

measurements at low temperatures. It was found that (2 2 0) reflection peak was split 

into two sub-peaks with equal intensity below T* in XRD measurements. This fact 

indicates that LaPt 2Si 2 has an orthorhombic symmetry at low temperatures. The SAED 

patterns show (n/3 0 0) superlattice reflections with n = 1 and 2 below T*. These results 

strongly support the formation of CDW in LaPt 2Si 2. In contrast, we did not observe 

any anomalies in the temperature dependence of resistivity except the superconducting 

transition for YPt 2Si 2 and LuPt 2Si 2. These results are suggestive of no significant 

relation between CDW and superconductivity in the RPt 2Si 2 compounds. 

[1] R.N. Shelton et al, Solid State Commun. 52 (1984) 797. [2] F C Ragel, et al , J. Phys. Condens. 

Matter 20 (2008) 055218. [3] M. Kumar et al. Phys. Rev. B 81 (2010) 125107. 

SB15 

Magnetic property in ferromagnetic superconductor UGe 2 above 

ferromagnetic critical pressure 

Naoyuki Tateiwa 1 *, Yoshinori Haga 1 , Tatsuma D Matsuda 1 , Eetsuji Yamamoto 1 , 

Yoshichika Onuki 2 and Zachary Fisk 3 

1 Advanced Science Research Center,, Japan Atomic Energy Agency, Japan 



UGe_2 is a ferromagnet with the Curie temperature of 54 K at ambient pressure. 

The ferromagnetic transition temperature decreases with increasing pressure. The 

superconductivity appears in the pressure region of 1.0-1.6 GPa where UGe_2 is in 

the ferromagnetic state. Ferromagnetic state disappears above P_c =1.6 GPa. Previous 

studies up to 2 GPa showed that the broad maximum appears in the temperature 

dependence of the ac magnetic susceptibility and that the ferromagnetic state is 

induced at metamagnetic field H_m above P_c. These phenomena are resemblance to 

weak ferromagnetic compound in the 3d electron system such as ZrZn_2. In this study, 

we have measured the dc-magnetization up to 4.1 GPa using the ceramic anvil high 

pressure cell. We confirmed the maximum at T_max in the temperature dependence of 

the dc magnetic susceptibility. With increasing pressure, T_max is increased from 24 K 

at 1.9 GPa to 32 K at 2.6 GPa. The peak structure around T_max becomes broader with 

increasing pressure and disappears above 4 GPa. The metamagnetic transition field H_ 

m increases rapidly with increasing pressure. We discuss the experimental results with 

the phenomenological spin-fluctuation theory. 

SB16 

Electron and hole transmission through superconductor - normal 

metal interfaces 

Kurt Gloos* and Elina Tuuli 

Department of Physics and Astronomy, University of Turku, Finland 

We have investigated the transmission of electrons and holes through interfaces 

between superconducting aluminum (T_c = 1.2 K) and various normal metals (copper, 

gold, palladium, platinum, silver) using Andreev-reflection spectroscopy at T = 0.1 K. 

Most of the contacts had the typical Andreev reflection spectra and could be analyzed 

with the modified BTK theory. We included Dynes' lifetime as a fitting parameter 

Γ in addition to superconducting energy gap 2Δ and normal reflection described 

by Z. For contact areas from 1 nm 2 to 10 000 nm 2 the BTK Z parameter was 0.5, 

corresponding to transmission coefficients of about 80%. This is considerably larger 

than estimated based on reports of other experimental methods (proximity effect 

and CPP resistance of multilayers) or expected theoretically. The small variation of 

Z indicates that the interfaces have a negligible dielectric tunneling barrier and that 

Fermi surface mismatch does not depend on the normal metal. Our results contradict 

standard expectations and call for a revision of the interpretation of the BTK theory 

and normal reflection. This is an especially important topic for applying Andreevreflection 

spectroscopy to unconventional superconductors or for measuring the local 

spin polarization of ferromagnets.

SB17 

Magnetic field-induced odd-frequency superconductivity in s-wave 


Masashige Matsumoto 1 *, Mikito Koga 2 and Hiroaki Kusunose 3 

1 Department of Physics, Fuclty of Science, Shizuoka University, Japan 

2 Department of Physics, Fuculty of Education, Shizuoka University, Japan 

3 Department of Physics, Ehime University, Japan 

The wavefunction of the Cooper pair of the conventional BCS state is characterized 

by the even parity (s-wave) and spin singlet state. It is well known that an external 

magnetic field modifies the wavefunction of the Cooper pair and breaks the 

conventional BCS superconducting state. We find that the wavefunction of the 

modified Cooper pair contains a spin triplet component with the s-wave orbital 

symmetry. While the spin triplet s-wave Cooper pair is forbidden owing to the fermion 

property, it is permitted in the generalized theoretical framework containing the oddfrequency 

dependence of the order parameter. We investigate this point on the basis of 

the self-consistent calculation in the Eliashberg theory and find that the odd-frequency 

order parameter coexists with the even-frequency one [1]. We also report how physical 

properties are affected by the induced odd-frequency superconducting order parameter 

[2]. 

[1] M. Matsumoto, M. Koga, and H. Kusunose, J. Phys. Soc. Jpn. Vol. 81, 033702 (2012). 

[2] H. Kusunose, M. Matsumoto, and M. Koga, Phys. Rev. B Vol. 85, 174528 (2012). 

SB18 

Enhanced pinning properties and the zero-resistance state in melttextured 

high-Tc superconductors probed by pulsed magnetic fields 

Fabio Teixeira Dias 1 *, Valdemar Das Neves Vieira 1 , Douglas Langie Da Silva 1 , Sabrina Esperanca 

Nunes 1 , Frederik Wolff-Fabris 2 , Erik Kampert 2 , Jacob Schaf 3 and Joan Josep Roa Rovira 4 

1 Department of Physics, Universidade Federal de Pelotas, 96010-900, Pelotas, Brazil 

2 Dresden High Magnetic Field Laboratory, HZ Dresden-Rossendorf, 01314, Dresden, Germany 

3 Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, Brazil 

4 Universite de Poitiers, 86962, Poitiers, France 

Among several techniques to grow high-temperature superconductors, melt-textured techniques have emerged as an 

alternative way to produce materials with physical properties needed for some technological applications. In this work 

we have studied the correlation between the magnetic irreversibility line and the zero-resistance state in melt-textured 

YBaCuO samples (Y123) with inclusions of Y211 phase particles by performing magnetization and magnetotransport 

measurements in DC and pulsed magnetic fields up to 60 T and temperatures down to 1.5 K [1]. Our results show for inplane 

magnetic fields an irreversibility field higher than 40 T at 77 K which evidences a strong pinning effect due to the 

interface of the Y211 particles embedded in the Y123 phase. We have observed effects of the intrinsic pinning due to the 

anisotropic superconductivity of the Y123 phase. Access to pulsed high magnetic fields reveals a suppression of the lowtemperature 

magnetic irreversibility field relative to BC 2. These results show experimental evidences for field-induced 

microscopic quantum fluctuations as observed in different high-Tc superconductors. Our findings in melt-textured 

YBCO samples exclude the possibility that the zero-resistance state and the magnetic irreversibility merge in this field 

range [2,3,4], showing evidences of weak granularity and providing a good candidate for technological applications. 

[1] J. Schaf, P. Pureur, F. Dias, V. Vieira, P. Rodrigues Jr., and X. Obradors, Phys. Rev. B 77, 134503 (2008). [2] C. Ebner 

and D. Stroud, Phys. Rev. B 31, 165 (1985). [3] P. Pureur, R. Costa, J. Roa-Rojas, and P. Prieto, Phys. Rev. B 61, 12457 (2000). 

[4] J. Rosenblatt, P. Peyral, A. Raboutou, and C. Lebeau, Physica B 152, 95 (1988). 

SB19 

Phenomena of vortex pinning by composite pinning array on Nb films 

Sheng Hao Wang 1 *, Lance Horng 1 , T. C. Wu 2 , Chien-miao Chen 1 , R Cao 1 and J. C. 

Wu 1 

1 Dept. of Physics, National ChangHua University of Education, Taiwan 

2 Dept. of Electronic Engineering, National Formosa University, Taiwan 

In type II superconductor, magnetic fields can penetrate into the superconductor 

inhomogeneously as an array of vortices. The interaction of these vortices and vortexpin 

interactions in the superconductor give rise to a rich variety of static and dynamical 

phases. In our study, smaller pinning sites at the center of every hexagonal cell were 

added when fabricating film with honeycomb array to obtain films with composite 

pinning array. It has been prepared on Si 3N 4-coated Si wafers using electron-beam 

lithography in conjunction with reactive ion etching. Then a dc sputtering completed 

the four-terminal geometry niobium films over the composite array. MR measurements 

were carried out by a four-probe technique. Special matching peaks of critical currents 

are exhibited at different temperatures in the measurements. The positions and structures 

of the matching peaks seem irregular and are very different from the structures of the 

matching peaks for previously explored films, such as films with triangular, square, or 

honeycomb pinning arrays. Considering the multiple-vortex filling of different pinning 

sites, we can give a reasonable explanation to this interesting phenomenon. 

T. C. Wu, R. Cao, T. J. Yang, L. Horng, J. C. Wu, Jan Kolacek, Solid State Commun. 143, 171 (2010) , 

R Cao, Lance Horng, T. J. Yang, T. C. Wu, J. C. Wang, and J. C. Wu, J. Appl. Phys. 107, 09E129 (2010) 

,T. C. Wu, J. C. Wang, Lance Horng, J. C. Wu, and T. J. Yang1, J. Appl. Phys. 97, 10B102 (2005) 

SB20 

SB21 

SB22 


Superconducting fluctuations near the Mott critical point 

Moon-sun Nam 1 , Cecile Meziere 2 , Patrick Batail 2 and Arzhang Ardavan 1 

1 

The Clarendon Laboratory, Department of Physics, University of Oxford, United 

Kingdom 

2 

Laboratoire MOLTECH-Anjou, UMR 6200 CNRS-Universite d'Angers, 2 Boulevard 

Lavoisier, F-49045 Angers, France 

The Nernst effect, the voltage that occurs transverse to crossed temperature gradient and 

magnetic field applied to a conductor, is a sensitive probe of superconducting fluctuations in 

unconventional superconductors such as the high-Tc cuprates [1] and organic superconductors 

[2]. The isostructural kappa-phase organic compounds (BEDT-TTF)2X offer a series of 

materials ranging from weakly correlated superconductors (X = Cu(NCS) 2) through strongly 

correlated superconductors (X = Cu[(N(CN) 2]Br) to Mott insulators (X = Cu[(N(CN) 2] 

Cl) as the bandwidth decreases and the importance of correlations increases. We previously 

showed that while there are no fluctuations significantly above Tc in the weakly correlated 

superconductor, there are strong superconducting fluctuations at temperatures up to 50% above 

Tc in the strongly correlated superconductor [2], suggesting that the proximity of the Mott state 

drives the fluctuating state. Here, by alloying the strongly correlated and the Mott insulating 

materials, we tune the system towards the Mott critical point. Superconductors in the vicinity 

of the critical point exhibit a large and magnetic-field-dependent Nernst effect, characteristic of 

superconducting fluctuations, at even higher temperatures. The effect is apparent over the whole 

temperature range for which the conductivity is metallic, up to 50K, about six times Tc. 

[1] Y. Wang, et al., Phys. Rev. B 73, 024510 (2006) [2] M.-S. Nam et al., Nature 449, 584 (2007) 

Anomalous hall effect in superconductors with spin-orbit interaction 

Pedro D Sacramento 1 , M. A. N. Araujo 2 , V R Vieira 1 , V K Dugaev 3 and J Barnas 4 

1 Departamento de Fisica and CFIF, Instituto Superior Tecnico, TULisbon, Portugal 

2 Departamento de Fisica and CFIF, Universidade de Evora, Portugal 

3 Department of Physics, Rzeszow University of Technology, Poland 

4 Department of Physics, Adam Mickiewicz University, Poland 

WITHDRAWN 

Analysis of the local current density in HTS coated conductors using 

low-temperature scanning laser and hall probe microscopy 

Sang Kook Park, Bo Ram Cho, Hee Yeon Park and Hyeong-cheol Ri* 

Department of Physics, Kyungpook National University, Korea 

Local current density in HTS coated conductors was investigated using Lowtemperature 

Scanning Laser and Hall Probe Microscopy (LTSLHPM). We prepared 

GdBCO and YBCO coated conductors to study the spatial distribution of the current 

density in a single bridge. Inhomogeneity of the local critical temperature in the 

bridge was analyzed from experimental results of scanning laser microscopy near the 

superconducting transition. The local transport and screening current in the bridge were 

also investigated using scanning Hall probe microscopy. From experimental results 

of scanning laser and Hall probe microscopy, we have observed the redistribution of 

current density and the critical temperature caused by defects of the HTS layer. 


Poster Friday

Poster Friday 

SB23 


Cooper pairing between conduction and localized electrons in heavyfermion 

systems 

Keisuke Masuda 1 * and Daisuke Yamamoto 2 

1 Department of Physics, Waseda University, Japan 

2 Condensed Matter Theory Laboratory, RIKEN, Japan 

We study the Cooper pairing between a conduction electron (c electron) and a localized 

f electron, referred to as the c-f paring, as a mechanism of s-wave superconductivity 

in heavy-fermion systems. To describe the physics of heavy-fermion systems, we start 

from the periodic Anderson model. We apply the Schrieffer-Wolff transformation to this 

model considering the situation where the f level is sufficiently deep and the Coulomb 

repulsion is finite but large. The resulting effective Hamiltonian includes direct and 

spin-exchange interactions between c and f electrons, which can be the driving force 

for the formation of the Cooper pairs. Within the mean-field approximation, we show 

that the c-f pairing state with anisotropic s-wave symmetry appears in a large region of 

the phase diagram. Such a pairing state can be realized when the quasiparticle band of 

the f electrons, which is formed by the strong Coulomb repulsion, is located near the 

energy level of the conduction band. We also discuss the relationship between the c-f 

pairing proposed here and the s-wave superconductivity found in the experiments on 

CeRu 2 and CeCo 2. 

SB24 

Low-temperature thermoelectric properties of the electron-doped 

Perovskites Sr 1-xCaxTi 1-yNbyO 3 

Tetsuji Okuda 1 *, Junichi Fukuyado 1 , Kurahito Narikiyo 1 , Mitsuru Akaki 2 and Hideki 

Kuwahara 2 


2 Sophia University, Japan 

Electron-doped perovskite SrTiO 3 is known to be one of candidates for an n-type 

thermoelectric (TE) oxide. [1] In this study, we tried to improve a TE property of a 

lightly-electron-doped SrTiO 3 single crystal below room temperature by substitutions 

of Ca and Nb for Sr and Ti. We found that SrTi 0.99Nb 0.01O 3 shows a large power factor 

of about 90 μW/K2 cm at 50 K and the largest dimensionless TE figure-of-merit (ZT ~ 

0.07) below 40 K among the ever-reported materials. The good n-type TE response is 

due to a distinct electron-phonon interaction which could relate to the superconducting 

state [2], which enlarges a Seebeck coefficient not through an enhancement of effective 

mass, but through a change of relaxation time. On the other hand, a Ca 2+ substitution 

for Sr 2+ increases the ZT at 300 K for Sr 1-xCaxTi 0.97Nb 0.03O 3 from 0.08 to 0.105. The 

enhancement of ZT originates not only in a large reduction of a thermal conductivity 

due to an introduced randomness into the crystal structure, but also in an unexpected 

enhancement of Seebeck coefficient by the Ca substitution. 

[1] T. Okuda, K. Nakanishi, S. Miyasaka, and Y. Tokura, Phys. Rev. B 63, 113104 (2001). [2] H. Suzuki, H. 

Bando, Y. Ootuka, I.H. Inoue, T. Yamamoto, K. Takahashi, and Y. Nishihara, J. Phys. Soc. Jpn. 65, 1529 

(1996). [3] J. Fukuyado, K. Narikiyo, M. Akaki, H. Kuwahara, and T. Okuda, Phys. Rev. B, to be published. 

SB25 

Evolution of pairing potential in ladder materials under 

renormalization group transformations 

Yen-chen Lee 1 *, Wen-min Huang 2 and Hsiu-hau Lin 1 


2 Physics Division, National Center for Theoretical Sciences, Taiwan 

It is generally believed that electron-electron interactions are responsible for pair 

formation in unconventional superconductors. However, how electrons can form 

pairs in the presence of repulsive interactions remains counterintuitive and puzzling. 

Many studies suggest that spin fluctuations provides the “pairing glues” to account for 

the unconventional pairing. Here we take a different route: finding effective pairing 

potential at different length scales by renormalization group approach. We focus on 

the unconventional superconductivity in ladder materials and show how the profile 

of electron-electron interactions evolves under renormalization group transformation. 

Starting with repulsive short-ranged interaction, compelling evidence for spatially 

structured attractive interactions emerges in long-wavelength limit and explains the 

unconventional pairing symmetry naturally. Comparisons with other theoretical 

approaches and potential generalization to two dimensions are discussed at the end. 


SB26 

Evidence for multiband order parameters in the stong-coupling 

LaRu 4As 12 Skutterudite Superconductor 

Tomasz Cichorek 1, Lukasz Bochenek 1, Ryszard Wawryk 1, Roman Puzniak 2 and 

Zygmunt Henkie 1 

1 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 

Wroclaw, Poland 

2 Institute of Physics, Polish Academy of Sciences, Warsaw, Poland 

Superconducting properties of high-purity LaRu 4As 12 single crystals with the highest 

critical temperature Tc = 10.45 K among the fully filled-skutterudite superconductors 

were investigated by dc magnetization, electrical resistivity, torque, and specific heat 

measurements both as a function of temperature and magnetic field. At B = 0 and 

below about Tc/2, the electronic specific heat exhibits two-band features, as concluded 

from an α-model analysis. Multi-band effects are further inferred from a nonlinear 

magnetic-field dependence of the electronic specific heat coefficient in the zerotemperature 

limit as well as from a positive curvature of the upper critical field in the 

vicinity of Tc. Our findings, combined with results of previous de Haas-van Alphen 

experiments, suggest that enhanced superconductivity in LaRu 4As 12appears along with 

a spherical Fermi-surface sheet enclosing a small volume in the center of the Brillouin 

zone. 

SB27 

NMR Study of magnetic order and the FFLO state in CeCoIn 5 

Ken-ichi Kumagai 1 *, Hiroyuki Shishido 2 , Takasada Shibauchi 2 and Yuji Matsuda 2 

1 Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan 

2 Department of Physics, Kyoto University, Kyoto 606-8502, Japan 

A strongly-correlated superconductor, CeCoIn 5 is believed to host a Fulde-Ferrell- 

Larkin-Ovchinnkov (FFLO) state in a restricted region of high field and very low 

temperature. In addition to the field evolution of NMR results for H//a-axis [1], we 

will report recent results of the angle,θ, dependence of external fields with respect to 

the ab planes down to ~50mK. Detail phase diagram for θ-, B-, and T-parameters is 

obtained. The NMR spectra change dramatically upon entering the novel SC phase. 

A well-separated peak structure at the In(2b) site suggests the occurrence of the 

magnetic order which is emerging only in the newly-discovered SC state. The structure 

of the spin density wave (SDW) is modified with angle and field. The Knight shift 

of CeCoIn 5 provides a direct evidence for the emergence of the spatially-distributed 

normal quasiparticle region. The quantitative analysis for the field evolution of the 

paramagnetic magnetization and low-lying energy quasiparticle density of state is 

consistent with the nodal plane formation, which is characterized by an order parameter 

in the FFLO state. 

[1] K. Kumagai et al., Phys. Rev. Lett. 106, 137004 (2011). 

SB28 

MgB2 coated conductors grown at various temperatures by hybrid 

physical-chemical vapor deposition 

Mahipal Ranot 1 , K. H. Cho 1 , Soon-gil Jung 1 , Won Nam Kang 1 *, S. Oh 2 and K. C. 

Chung 3 

1 Physics, Sungkyunkwan University, Suwon, Korea 

2 National Fusion Research Institute, Korea 

3 Korea Institute of Machinery and Materials, Korea 

For practical applications, MgB 2 superconductor (T c~39 K) in the form of wires and 

tapes are required to be produced in long lengths to replace the conventional metallic 

superconductors, such as Nb-Ti and Nb 3Sn. In this work, we have grown MgB 2 coated 

conductors by depositing MgB 2 films directly on the flexible Hastelloy tapes at various 

temperatures ranging from 520 to 600 °C by using HPCVD. The MgB 2 coated conductors 

exhibit critical temperatures ranging from 37.5 to 38.5 K with superconducting transition 

width (T c) of about 0.3?0.8 K. X-ray diffraction analysis revealed that the MgB 2 coated 

conductors are polycrystalline in nature. It was found that the MgB 2 coated conductor 

grown at 520 °C had dense microstructure with good grain connectivity. However, upon 

increasing the growth temperature from 520 to 600 °C deterioration of grain connectivity 

takes place and void formations were observed. The critical current density (Jc) of the 

order of Jc(5 K, 0 T) ~107 and Jc(5 K, 3 T) ~105 A/cm2 was obtained for the MgB 2 coated 

conductor fabricated at 520 °C. The fabrication process, crystallographic orientations, 

surface morphologies and superconducting properties [T c, Jc (H)] of MgB 2 coated 

conductors grown at various temperatures will be discussed in detail.

SB29 

Low temperature properties of the weakly-coupled noncentrosymmetric 

superconductor LaNiC 2 

Jian Chen 1 , Jing Lei Zhang 1 , Lin Jiao 1 , Lin Yang 1 , Tian Shang 1 , Michael Nicklas 2 , 

Frank Steglich 2 and Hui Qiu Yuan 1 * 

1 Physical Department, Zhejiang University, China 

2 Max Planck Institute for the Chemical Physics of Solids, Dresden, Germany 

In a non-centrosymmetric (NCS) superconductor, an asymmetric potential gradient 

yields an antisymmetric spin-orbit coupling (ASOC), which splits the degeneracy of 

conduction electron, and allows the admixture of spin-singlet and spin-triplet pairing 

states, leading to accidental nodes in the energy gap [1,2]. It was shown that the timereversal 

symmetry is broken in the weakly correlated intermetallic compound LaNiC 2 

[3] but its pairing symmetry is still under debate. Here we present the low temperature 

specific heat C(T) and the magnetic penetration depth λ(T) for LaNiC 2. It is found 

that both λ(T) and Ce(T)/T can be well described by a phenomenological two-gap 

model. The Sommerfeld parameter, γ(H), increases steeply at low fields and eventually 

get saturated with increasing magnetic field, being also consistent with the behavior 

of two-gap superconductivity. We argue that the ASOC is weak in LaNiC 2 and the 

spin-singlet state dominates in the pairing states, giving rise to two-gap-like BCS 

superconductivity. 

[1] P. A. Frigeri, D. F. Agterberg, A. Koga, and M. Sigrist, Phys. Rev. Lett. 92, 097001 (2004). [2] H. Q. 

Yuan, D. F. Agterberg, N. Hayashi, P. Badica, D. Vandervelde, K. Togano, M. Sigrist, M. B. Salamon, Phys. 

Rev. Lett. 97, 017006 (2006). [3] A. D. Hillier, J. Quintanilla, R Cywinski, Phys. Rev. Lett. 102, 117007 (2009). 

SB30 

Magnetic penetration depth and $H$-$T$ phase diagram in SrPd 2Ge 2 

H. Kim 1 , N. H. Sung 2 , M. A. Tanatar 1 , B. K. Cho 2 and R. Prozorov 1 * 

1 The Ames Laboratory, USA 

2 School of Materials Science and Engineering, Gwangju Institute of Science and 


In-plane magnetic penetration depth, $\lambda(T)$, was measured in single crystals of 

SrPd 2Ge 2 superconductor down to 50 mK and in magnetic fields up to $H_{dc} = 1$ T by 

using a self - oscillating tunnel diode resonator operating at 16 MHz with amplitude of $H_{ac} 

≈ 20$ mOe. In the pure Meissner state, at $H_{dc}=0$, $ \lambda(T)$ saturates exponentially 

approaching $T\rightarrow 0$ indicating fully gapped superconductivity in SrPd$_2$Ge$_2$. 

In a magnetic field, the measured penetration depth is given by $\lambda^2 = \lambda^2_L + 

\lambda^2_C$, where $\lambda^2_C ~ B/j^2_c$ is the Campbell penetration depth and $j_c$ 

is the critical current density. For $H < 0.4$ T, the shortest $\lambda_C$ (strongest pinning) is 

achieved not at the lowest, but at some intermediated temperature. Additionally, $Δ \lambda(T)$ 

shows hysteresis between zero field cooling and field cooling measurements, which is an 

indication of non - parabolic pinning potential. Another interesting feature is a pronounced 

finite diamagnetic response above bulk superconducting transition, which could be related to 

superconducting fluctuations. Combining all measurements, the entire $H-T$ phase diagram 

of SrPd 2Ge 2 has been constructed. Possible pairing mechanism and the superconducting gap 

structure, unusual vortex response and field - and temperature dependent critical current density 

will be discussed. 

SB31 

Eliashberg function of the overdoped Bi 2212 superconductors deduced 

from the high resolution laser ARPES intensity 

Jin Mo Bok 1 *, Han-yong Choi 1 , Junfeng He 2 , X. J. Zhou 3 and C. M. Varma 4 

1 Department of Physics, SungKyunKwan University, Suwon 440-746, Korea 

2 Institute of Physics, Chinese Academy of Sciences, Beijing 100190., China 

3 Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 

4 Department of Physics and Astronomy, University of California, Riverside, CA 

92521, USA 

We report the diagonal and off-diagonal Eliashberg functions a2F(+) and a2F(-) of 

overdoped Bi2212 supercondcutors deduced from the high resolution laser APRES 

experiments. By fitting the momentum distribution curves of the ARPES intensity 

employing the superconducting Green's function, the diagonal and off-diagonal selfenergies 

along several cuts in the Brillouin zone are extracted. Then, the diagonal and 

off-diagonal Eliashberg functions are deduced by inverting the d-wave Eliashberg 

equation using, respectively, the conrresponding self-energies. We will present the 

momentum and frequency dependences of the Eliashberg function a2F(+) and a2F(-). 

We then compare these results with other experiment and calculation results. 

SB32 

SC01 

SC02 


The momentum and frequency dependences of the self-energy induced 

by the spin fluctuations for the cuprate superconductors 

Seung Hwan Hong and Han-yong Choi* 

Department of Physics, SungKyunKwan University, Korea 

We solve the momentum resolved d-wave Eliashberg equation to investigate the 

consistency of the spin fluctuation induced superconductivity theory for the cuprates. 

The effective interaction between electrons (Eliashberg function) is modeled in terms 

of the magnetic excitation spectrum measured by the inelastic neutron scattering on the 

LSCO superconductors reported by Vignolle et al[1]. The magnetic excitation spectrum 

consists of three parts: the resonance mode near 40-70 meV and the incommensurate 

parts above and below the resonance mode. The resonance mode has a peak at (π,π). 

The low energy incommensurate part makes a nonmonotonic momentum dependence 

of the diagonal and off-diagonal self-energies. On the other hand, the resonance mode 

makes a monotonic momentum dependence of the self-energy. The angle dependence 

of the superconducting gap is influenced by the effects of these two energy scales. 

These results are compared with the ARPES experiments. 

[1] B. Vignolle et al., Natrue Physics 3, 163 (2007) 

Novel non-centrosymmetric superconductors in 113 and 111 crystal structures 

Friedrich Kneidinger 1 *, Ernst Bauer 1 , Herwig Michor 1 , Gerfried Hilscher 1 , Isolde Zeiringer 2 , 

Peter Rogl 2 , Nataliya Melnychenko 3 , Leonid Salamakha 4 and Adrian Hillier 5 

1 Institute of solid state physics, Vienna University of Technology, Austria 

2 Institute of physical chemistry, University of Vienna, Austria 

3 Inorganic Chemistry Department, Ivan Franko National University of Lviv, Ukraine 

4 Ivan Franko Lviv National University, Ukraine 

5 ISIS facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation 

Campus, United Kingdom 

Superconductivity (SC) in materials that don’t possess a center of inversion due to their crystal structure has 

been recently found in materials like CePt_3Si[1]. The lack of inversion-symmetry gives rise to an electrical 

field and therefore leads to an antisymmetric spin-orbit coupling (ASOC) of the Rashba-type[2]. This causes 

a splitting of the Fermi surface, thereby leading to a superposition of spin-singlet and spin-triplet Cooper pairs 

in the SC condensate. Intriguing features like nodes in the superconducting gap, as well as H_c2 exceeding 

the Pauli-Clogston limit, may occur. However, besides Li_2Pt_3B[3], spin-triplet pairing seems only to be 

dominant in heavy fermion systems. In order to study these features in further detail, new ternary compounds 

like BaPtSi_3[4], SrPdSi_3, SrPdGe_3[5], SrPtSi_3 and SrPtGe_3 of BaNiSn_3 type (space group I/4mm) 

as well as promising 111-types like LaPtSi[6,7] and LaIrSi[8] have been investigated, since there is a tuning 

possibility regarding the quadratic atomic number dependency (Z²) of the spin-orbit coupling. Measurements 

of the electrical resistivity and the specific heat have been conducted to analyze the superconducting ground 

state. Additionally, μSR measurements have been performed to proof the microscopic pairing mechanism of 

the Cooper pairs. The results obtained so far indicate s-wave fully gapped BCS SC. 

[1] E. Bauer et al., Phys. Rev. Lett. 92, 027003 (2004) [2] Y.A. Bychkov and E. I. Rashba, JETP Lett 39, 78 (1984) 

[3] M. Nishiyama et al., Phys. Rev. Lett. 98, 047002 (2007) [4] E. Bauer et al., Phys. Rev. B 80, 064504 (2009) 

[5] K. Miliyanchuk et al., Journal of Physics: <strong>Conference</strong> Series 273, 012078 (2011) [6] K. Klepp & E.Parthe, 

Acta Crystallogr. B38, 1105 (1982) [7] J. Evers, G. Oehlinger and A. Weiss, Solid State Communications, Vol. 

50, No. 1, pp. 61-62, (1984) [8] K. Klepp & E.Parthe, Acta Crystallogr. B38, 1541 (1982) 

Non-fermi liquid behavior of d-wave superconductor 

Pankaj Singh*, Ajay Pratap Singh Gahlot, Manju Rani and Partho Goswami 

PHYSICS DEPARTMENT, DESHBANDHU COLLEGE, UNIVERSITY OF DELHI, 

India 

The d+id-density wave (Chiral DDW) order, at the anti-ferromagnetic wave vector 

Q = (π,π), is assumed to represent the pseudo-gap (PG) state of a hole-doped cuprate 

superconductor. The d-wave superconductivity (DSC), driven by an assumed attractive 

interaction, is discussed within the BCS framework together with the d+id ordering. 

The single-particle excitation spectrum in the CDDW + DSC state is characterized by 

the Bogoluibov quasi-particle bands-a characteristic feature of SC state. The coupled 

gap equations are solved self-consistently together with the equation to determine 

the chemical potential (μ). With the pinning of the van Hove-singularities close to μ, 

one is able to calculate the thermodynamic properties of the under-doped cuprates 

in a consistent manner. Apart from the known facts that PG and DSC represent 

two competing orders as the former brings about a depletion of the spectral weight 

available for pairing in the anti-nodal region of momentum space and the depletion 

of the spectral weight below Tc at energies larger than the gap amplitude, we find 

a conspicuous feature that the electronic specific heat displays non-Fermi liquid 

behavior( anomalous temperature dependence) in the CDDW + DSC state. 


Poster Friday

Poster Friday 

SC03 


Low temperature enhancement of the critical current in CeCoIn 5. 

Possible signature of magnetic order. 

C. F. Miclea 1 *, M. Nicklas 2 , A. C. Mota 3 , M. M. Altarawneh 4 , C. Miclea 1 , N. 

Harrison 4 , J. Thompson 4 , F. Steglich 2 and R. Movshovich 4 

1 National Institute for Materials Physics, 077125 Bucharest-Magurele, Romania 

2 Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany 

3 Solid State Laboratory, ETH Zurich, Switzerland 

4 Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA 

We report on vortex dynamics, dc magnetization and RF penetration depth measurements in 

the heavy fermion compound CeCoIn 5 down to low temperatures, T=50 mK. No strong pining 

is observed as expected for a clean limit superconductor which does not break spontaneously 

any additional symmetries besides the U(1)-gauge. CeCoIn 5 display clear logarithmic relaxation 

curves as expected from Kim-Anderson theory. The temperature dependence of the relaxation 

rate, S, with a small but finite residual value indicate that quantum tunneling plays a significant 

role in the vortex creep only at very low temperatures. Remarkably, a new phase transition 

marked by a strong increase in the remnant magnetization, Mrem is observed around T = 0.3 K 

in low magnetic fields just high enough to put the sample in the Bean critical state. Moreover, 

this anomaly is corroborated by the DC magnetization and RF measurements at very low fields. 

We extended the vortex dynamics investigation to Pb irradiated CeCoIn 5. While the defects 

created by irradiation have a clear effect on the relaxation rates the enhancement of Mrem 

still takes place at the same temperature. Our findings are consistent with the existence of a 

magnetically ordered phase, deep inside the superconducting state. 

SC04 

Superconducting phase diagram in fcc phase of Cs 3C 60; A pressure 

dependence of resistivity 

Takashi Kambe*, Yuta Suzuki, Seizi Shibasaki, Keitaro Tomita and Yoshihiro 

Kubozono 

Physics, Okayama university, Japan 

Cs 3C 60 crystallizes three polymorphic phases; A 15, fcc and bco. Two polymorphs, A 15 

and fcc phases, show pressure induced superconducting transitions around 38 K and 

35 K, respectively. Here we report a resistivity for fcc phase of Cs 3C 60 as a function of 

pressure and present a dome-shaped superconducting phase diagram. 

SC05 

The superconducting phases of URu 2Si 2 from sound velocity 

measurements 

B S Shivaram 1 , V W Ulrich 1 and D G Hinks 2 

1 Physics, University of Virginia, USA 

2 Materials Science Division, Argonne National Labs, USA 

High resolution measurements of the changes in the longitudinal sound velocity in 

a magnetic field have been performed in the zero temperature limit in high quality 

single crystals of URu 2Si 2. These measurements reveal two distinct signatures 

attributable to multiple superconducting phases. A step change in the sound velocity, 

for propagation in the basal plane, is observed at the critical field, Bc 2. This step 

broadens considerably as T tends to Tc with a concomitant decrease in magnitude. A 

second step is observed at a field ~0.5 Bc 2 and it's magnitude remains constant at all 

temperatures. Inductive measurements of the transitions in a magnetic field, however, 

reveal only a single signature which coincides with the lower step change in the sound 

velocity. Measurements performed with B oriented at various angles between the a and 

c-axes reveal a weaker angular dependence of the lower step and confirm the rapid fall 

off of Bc 2 close to B||c-axis. A multiple superconducting phase diagram for URu 2Si 2 is 

proposed. 


SC06 

Electronic structure of a superconducting boride, ZrB12 Sangeeta Thakur 1 , Deep Narayan Biswas Biswas 2 , Nishaina Sahadev 3 , Geetha 

Balakrishnan 4 and Kalobaran Maiti 5 * 

1 

Department of Condensed Matter Physics and Materials' Science, Tata Institute of 

Fundamental Research Colaba, Mumbai - 400 005, India 

2 

Tata Institute of Fundamental Research Colaba, Mumbai - 400 005, India 

3 

Tata Institute of Fundamental Research, Colaba, Mumbai - 400 005, India 

4 

Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, United 

Kingdom 

5 

Tata Institute of Fundamental Research Colaba Mumbai 400005, India 

Borides have attracted a great deal of attention followed by the finding of varied interesting 

properties. ZrB 12 is one such compound exhibiting highest superconducting critical 

temperature (Tc = 6 K) in MB12 family. In order to probe the electronic states responsible 

for superconductivity in this compound, we studied the electronic structure of single 

crystalline ZrB 12 using high resolution photoemission spectroscopy and ab initio band 

structure calculations. Zr 3d core level spectra exhibit signature of satellite features indicating 

finite correlation among the conduction electrons. The B 1s spectra appears to be sharp with 

unusual asymmetry, presumably due to surface contributions as found in hexaborides. In 

the valence band spectra, the spectral density of states reveal a dip at the Fermi level, which 

gradually increases with the decrease in temperature down to 10 K. The band structure results 

indicate dominant contribution from the B 2p electronic states in the valence band. However, 

the photon energy dependence in the experimental spectra indicate large contribution from 

the Zr 4d states near Fermi level suggesting their important role in the superconductivity. 

SC07 

On the nature of an energy barrier between (π,0) and (0,π) magnetic 

orders in Fe pnictides 

Alexander Yaresko 1 *, Lilia Boeri 2 , Vladimir Antropov 3 and Ole Krogh Andersen 2 

1 Andersen, Max Planck Institute for Solid State Research, Germany 

2 Max Planck Institute for Solid State Research, Germany 

3 Ames Laboratory, Ames, Iowa, USA 

As temperature is lowered most of undoped Fe arsenides, parent compounds for 

recently discovered Fe based superconductors, undergo a transition into a collinear 

state with stripe-like magnetic order in which anti-ferromagnetic (AFM) Fe chains 

are ferromagnetically ordered along the direction perpendicular to the chains. Two 

such collinear magnetic structures, characterized by ordering vectors (π,0) or (0,π), 

are connected by infinite number of non-collinear states with two AFM sublattices 

of second Fe neighbors rotated by an arbitrary angle with respect to each other. In a 

classical Heisenberg model all these states are degenerate. Band structure calculation 

show, however, that the degeneracy is lifted already at the mean field LSDA level and 

that in Fe arsenides (π,0) and (0,π) magnetic orders are separated by an energy barrier 

comparable to the energy difference between Neel and stripe AFM orders. We discuss 

a microscopic origin of the energy barrier and demonstrate that it is caused by closely 

related to underlying band structure. The results for Fe arsenides are compared to 

BaMn 2As 2 and hypothetical KFe 2Se 2 for which we found that a non-collinear 90-degree 

spin arrangement is more favorable than collinear ones. A doping dependence of the 

barrier is also discussed. 

SC08 

Electronic structures and magnetic properties of LnFeAsO 

Chang Hyun Yi, Ju Young Kim, Jae Kyung Chang, and Joo Yull Rhee 

Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea 

Recently, high transition-temperature superconductivity was discovered in the 

ironpnictide RFeAsO (R=rare-earths) family of materials. Among them, LaFeAsO 

undergoes a tetragonal-to-orthorhombic phase transition at ~160 K followed by an 

antiferromagnetic ordering at ~145 K. This material has also been reported to undergo 

a spin-density wave transition near 150 K. Through first-principles calculations we 

tried to understand the electronic structures and magnetic properties of LaFeAsO. We 

used full-potential linearized-augmented-planewave method in the antiferromagnetic 

ground state with orthorhombic phase. The physical origin of the SDW formation will 

be discussed.

SC09 

Phase transition of a heavy fermion superconductor in a high magnetic 

field : entanglement analysis 

Reza Afzali 1 * and Neda Ebrahimian 2 

1 Physics Department, K. N. Toosi University of Technology, Tehran 15418, Iran 

2 Physics Department, Amirkabir University of Technology, Tehran 15914, Iran 

When the magnetic field is acting on the spin of electrons only, a transition from a normal to a 

modulated superconducting state or FFLO superconductor state may occur at low temperatures[1-3]. 

A FFLO superconducting state, accompany with an order parameter that oscillates spatially, may be 

stabilized by a high applied magnetic field or a molecular field. CeCoIn 5 is a sample of heavy-fermion 

superconductor[4]. Initially experiments on CeCoIn 5 indicate that in this substance a FFLO state in a 

exchange field is realized. Quantum multipartite entanglement is a new procedure for investigating 

quantum phase transition[5-6], which is one of the interesting topics in condensed matter. In this 

article, we deal with to the phase transition of FFLO state of CeCoIn 5 to the normal state by obtaining 

quantum multipartite entanglement of the system. For this purpose, using normal and anomalous Green 

functions and density matrix, concurrence, as a measure of bipartite entanglement, is obtained. Then, 

order parameter and magnetic field dependence of multipartite entanglement in momentum space is 

calculated. The phase transition is determined and the behavior of the system based on order parameter 

is discussed. Furthermore, the phase transitions of both BCS and FFLO states to the normal state are 

compared. 

References: [1]Fulde P and Ferrell R A 1964 Phys. Rev. A 135 550 [2]Larkin A I and Ovchinnikov Y N 1965 

Sov. Phys. JETP 20 762 [3]Takada S and Izuyama T 1969 Prog. Theor. Phys. 41 635 [4]Radovan H A, Fortune 

N A, Murphy T P, Hannahs S T, Palm E C, Tozer S W and Hall D 2003 Nature 425 51 [5] Amico L, Fazio R, 

Osterloh A and Vedral V 2008 Rev. Mod. Phys. 80 517 [6] Brandao F G S L 2005 New J. Phys. 7 254 

SC10 

Spin and charge excitations in antiferromagnetic metallic phase in 

multi-orbital systems: A case study of chromium 

Koudai Sugimoto 1 , Eiji Kaneshita 2 , Kenji Tsutsui 3 and Takami Tohyama 1 * 

1 Yukawa Institute for Theoretical Physics, Kyoto University, Japan 

2 Sendai National College of Technology, Japan 

3 Condensed Matter Science Division, JAEA, Japan 

Since the discovery of Fe-based superconductors, it has been recognized that the 

interplay of spin, charge, and orbital degrees of freedom is the key to understanding 

the physics of multiband itinerant systems. Antiferromagnetic (AF) phase seen in 

the parent compounds of Fe-based superconductors is a good example to study the 

multi-orbital physics in the metallic phase. The AF metallic phase similar to the 

parent compounds is realized in a simple chromium metal with AF order. To make 

a unified view in the AF metallic phase of multi-orbital systems, we study spin and 

charge excitations in AF Cr. We calculate the optical conductivity, neutron scattering 

spectra, and Cr L-edge resonant X-ray scattering (RIXS) spectra based on the meanfield 

theory for the multi-band Hubbard model and the random-phase approximation. 

The calculated results of the optical conductivity and neutron scattering spectra are 

compared with corresponding experimental data. The d etailed polarization and 

momentum dependence in RIXS is also discussed with predictions for the experiments. 

SC11 

The dirty crossover - signature of a robust superfluid in the unitary 

regime. 

IIT Guwahati 

IIT Guwahati, India 

We perform a systematic study of the BCS-BEC crossover in an ultracold fermionic 

gas in presence of a weak white noise-like random disorder which is incorporated 

in our mean-field treatment via Gaussian fluctuations. A careful investigation of 

different mean field quantities as a function of the interparticle interaction reveals a 

nonmonotonic behavior in the the condensate fraction data as disorder is included 

in our calculations. The inflexion point is seen to occur in the unitary regime, and 

afterwards there is a gradual depletion of the condensate density in the BEC side, 

thereby corroborating a robust paradigm of superfluidity in the unitary regime. 

Motivated by this result, we study the spectral gap and the density of states in the 

crossover region and their responses to the disorder. We further include a comparative 

discussion on the role of the pair and phase coherence lengths in this region in presence 

of disorder to assess how these results can be relevant to the ongoing discussion. Due 

to tremendous progress taking place in the experimental front in manipulating atoms 

on an optical lattice in presence of (speckle) disorder, a stable superfluid scenario in the 

unitary limit, as proposed here, may soon be realizable. 

Prof. S.S. Mandal, Indian Association for Cultivation of Science, Kolkata, India Prof. Y. Yanase, 

Niigata University, Japan 

SC12 

SC13 

SC14 


Spin-orbit coupling and the superconductivity in simple-cubic 

polonium 

Chang-jong Kang, Kyoo Kim and B. I. Min* 

Physics, POSTECH, Korea 

Polonium is the only element which has the simple-cubic (SC) structure in the 

periodic table. We have studied its structural stability based on the phonon dispersion 

calculations using the first-principles all-electron full-potential band method. We have 

demonstrated that the strong spin-orbit coupling (SOC) in SC-Po suppresses the Peierls 

instability and makes the SC structure stable. Further, we have investigated the possible 

superconductivity in SC-Po, and predicted that it becomes a superconductor with Tc 

~ 4 K at ambient pressure. The transverse soft phonon mode at q ~ 2/3 R, which is 

greatly affected by the SOC, plays an important role both in the structural stability and 

the superconductivity in SC-Po. We have explored effects of the SOC and the volume 

variation on the phonon dispersions and superconducting properties of SC-Po. 

Stability of FFLO states in optical lattices with layered structure 

Akihisa Koga* and Yasuharu Okawauchi 

Department of Physics, Tokyo Institute of Technology, Japan 

Recently, ultracold fermions with spin-imbalanced populations have attracted much 

interest. One of the interesting questions is how the Fulde-Ferrell-Larkin-Ovchinnikov 

(FFLO) phase, where Cooper pairs are formed with a finite total momentum, is realized 

in the system. In the two dimensional optical lattice with a confining potential, it has 

been pointed out that two kinds of FFLO states are realized[1,2]. On the other hand, 

such FFLO states with a three-dimensional structure have not been studied so well 

although the interlayer coupling should be important for realistic optical lattice systems. 

Motivated by this, we investigate the stability of the superfluid state in a layered 

fermionic optical lattice system with a confining potential, using the Bogoliubov de- 

Gennes equations. It is clarified that in the imbalanced case, the introduction of the 

interlayer hopping stabilizes the radial FFLO state, while makes the angular FFLO 

state unstable. We also discuss the system size dependence of the superfluid ground 

state. It is clarified that in a certain ring region the A-FFLO state is indeed realized in a 

large system. 

[1] Y. Chen, Z. D. Wang, F. C. Zhang, and C. S. Ting, Phys. Rev. B 79, 054512 (2009) [2] Y. Yanase, 

Phys. Rev. B 80, 220510 (2009) 

Flux quantization and its magnetic relaxation in a micrometer-sized 

superconducting ring of niobium 

Jae-hyuk Choi 1 *, Heon-hwa Choi 1 , Yun-won Kim 2 , Soon-gul Lee 2 and Mahn-soo 

Choi 3 

1 

Division of Physical Metrology, Korea Reserach Institute of Standards and Science, 

Korea 

2 

Dep. of Display and Semiconductor Physics, Korea University, Korea 

3 

Dep. of Physics, Korea University, Korea 

We developed a high-sensitivity cantilever force magnetometry, which is capable 

of direct measurement of the magnetic moment of micron-scale samples at low 

magnetic fields and low temperatures, and studied magnetic properties of a 100 nmthick 

Nb superconducting ring with 4 micrometer radius and 2 micrometer width. At a 

temperature of 3.5 K, we observed flux quantization of h/2e period using ac torque and 

dc force magnetometries with attonewton and sub-piconewton sensitivity, respectively, 

determining the magnetic moment of each flux quantum. First demonstration of 

magnetic relaxation at single flux quantum level is also presented, which provides 

information about the dynamics of thermally-activated single flux quantums depending 

on their number. 


Poster Friday

Poster Friday 

SC15 


Measurement of rat biomagnetic signals by using a HTS-SQUID 

system 

In-seon Kim* and San Ahn 

Division of Convergence Technology, Korea Research Institute of Standards and 


We have measured biomagnetic signals in rats by using a high-TC SQUID 

magnetometer system employing a small magnetically shielded box. For the rat cardiac 

magnetic field measurements, healthy Wistar Kyoto rat and spontaneously hypertensive 

rat were anesthetized and fixed on a plastic xyz-stage in supine position inside the 

magnetically shielded box. Well defined P- , QRS- and T-waves were observed on 

the rat cardiac magnetic field measurements. We investigated circular measurements 

based on the hexaxial reference system, i.e., 12 measurement points were determined 

alongside the circumference of a circle centered at the heart position. These results 

were quite promising for use in biomedical applications of heart disease rat model 

study by using the high-TC SQUID magnetometer system. 

SC16 

Evolution of the effective mass approaching the quantum critical point 

in the heavy fermion superconductor CePt 2In 7 

Jakob Kanter 1 *, Philip J. W. Moll 1 , Filip Ronning 2 , Sven Friedemann 3 , Patricia L 

Alireza 3 , Michael Sutherland 3 , P. Tobash 2 , J. Thompson 2 , Eric D. Bauer 2 and Bertram 

Batlogg 1 

1 Laboratory for Solid State Physics, ETH Zurich, Switzerland 

2 Los Alamos National Laboratory, Los Alamos, New Mexico, USA 


We report Shubnikov-de Haas measurements on micro-structured CePt 2In 7 single 

crystals under high pressures. CePt 2In 7 belongs to the Ce mMnIn 3m+2n heavy fermion 

family and orders antiferromagnetically below 5.5 K. Applying pressure induces a 

superconducting phase and suppresses the AFM order with the Neel temperature 

extrapolating to a quantum critical point. The magnetic fluctuations associated with 

the QCP are thought to stabilize the unconventional superconducting phase. The 

evolution of the effective electronic masses approaching the quantum critical point is 

essential to the understanding of the electronic correlation leading to unconventional 

superconductivity. To this end we have developed a method to contact micro-structured 

samples inside a diamond anvil cell allowing for complex sample shapes and several 

electric contacts. 

SC17 

Thermal stability of an epoxy-impregnated HTS racetrack coil without 

turn-to-turn insulation for rotating machines 

Oh Jun Kwon, Kwang Lok Kim, Yoon Hyuck Choi, Hyun-jin Shin and Haigun Lee* 


MOVED 


SC18 

Design, fabrication, and testing of a cooling system using solid nitrogen 

for a 3 T/60-mm RT bore superconducting HGMS 

Jung-bin Song, Kwang Lok Kim, Dong Gyu Yang, Yoon Hyuck Choi, Jongseok Lee 

and Haigun Lee* 


SC19 

Purification of chemical mechanical polishing wastewater using a 2G 

HTS high gradient magnetic separation system 

Dong Gyu Yang, Jung-bin Song, Young-gyun Kim, Jongseok Lee, Yeonjoo Park and 

Haigun Lee* 


SC20 

MOVED 

MOVED 

Effect of liquid cryogen on a 2G HTS magnet using a mixed cryogen 

cooling system 

Kwang Lok Kim, Jung-bin Song, Yoon Hyuck Choi, Dong Gyu Yang and Haigun 

Lee* 


MOVED

SC21 





SC22 

MOVED 





SC23 

MOVED 

Powder neutron diffraction study of HoCoGa5 Riki Kobayashi 1 *, Koji Kaneko 1 , Shuichi Wakimoto 1 , Naoyuki Sanada 2 , Ryuta 

Watanuki 2 , Kazuya Suzuki 2 and Songxue Chi 3 

1 

Quantum beam science directolate, Japan atomic energy agency, Japan 

2 

Department of Advanced Materials Chemistry, Yokohama National University, 

Japan 

3 

Quantum beam science directolate, Oak Ridge National Laboratory, USA 

Ternary compound ACoGa 5(A=rare earth or actinide) attracts a much attention due to high 

temperature superconductivity in PuCoGa 5 and related compounds. In addition, recent 

study on TbCoGa 5 reveals another interesting aspects of this system ; successive transitions 

in TbCoGa 5 could be “components-separated orders” which may arise from a novel type 

of frustration between multipole. HoCoGa5 also exhibits successive transitions at TN1 = 9.6 

K and TN2 = 7.5 K. In order to investigate nature of these transitions in HoCoGa 5, neutron 

powder diffraction experiment were carried out. Appearance of superlattice refractions 

was clearly observed below TN1. In addition, we observed that both peak position and 

intensity of superlattice peaks abruptly change at TN2 on cooling. The observed peak in 

the phase I(T < TN2) and II(TN2 < T < TN1) can be described with q1=(1/2 0 1/2) and 

q2=(1/2 0 τ) with τ=0.35, respectively. The determined propagation vector of the phase 

I is the same as that of TbCoGa5, whereas that of phase II is altered. Detailed magnetic 

structure analysis for both phases are in progress. 

[1] J. L. Sarrao et al., Nature 420, 297 (2002). [2] F. Honda et al., Physica B 359, 1147 (2005). [3] N. 

Sanada et al., J. Phys. Soc. Jpn. 78, 073709 (2009). 

SC24 

SC25 

SC26 


Evidence of two-band gap superconductivity in LaRu 2P 2 

Tetsuya Fujiwara 1 *, Harunobu Sagawa 1 , Kazuyuki Matsubayashi 2 , Yoshiya Uwatoko2 

and Toru Shigeoka 1 



We investigate the electronic transport properties and the superconducting gap characteristics 

of LaRu 2P 2. Superconducting transition was recognized at Tc = 4.4 K in LaRu 2P 2 single 

crystal as reported in ref [1]. Values of upper critical field Hc 2 estimated from the electrical 

resistivity under magnetic field are isotropic in this system. These are good accordance with 

the results by Ying et al.[2]. However, they, although, claimed that LaRu 2P 2 is a conventional 

superconductor, so called BCS type, it was revealed that LaRu 2P 2 single crystal obtained in 

this work shows a remarkably larger Hc 2 than that expected from GL theory at considerably 

low temperature. In addition, we observed two clear discontinuities of specific heat at Tc 1 

= 4.4 K and Tc 2 = 4.0 K, respectively, in specific heat as a function of temperature. Each 

transition temperature vary obeying Hc 2(t)=Hc 2(0)(1-t2)/(1+t2), here, t = T/Tc, indicating 

that both discontinuities at Tc 1 and Tc 2 are attributed to superconducting transitions. So, we 

tried to analyze thermodynamic properties of LaRu 2P 2 by a two-band gap model [3]. In 

consequence, the numerically calculated C(T) curve was well reproduced experimentally 

measured specific heat as a function of temperature when Δ 1/kTc 1 and Δ 2/kTc 2 were 

assumed to be 1.5 and 3.0, respectively. 

[1] T. Fujiwara et al., J. Phys.: Conf. Ser. 273, 012112 (2011). [2] J. Ying et al., Supercond. Sci. 

Technol. 23, 115009 (2010). [3] H. Padamsee et al., J. Low. Temp. Phys. 12, 387 (1973). 

Proximity effect for asymmetrical three layered F/S structures in 

external magnetic field 

Maxim V. Avdeev, Sergey L. Tsarevskii and Yurii N. Proshin* 


We study the critical temperature Tc of the three-layered ferromagnet/superconductor 

(F/S) structures at the external magnetic field H parallel to the film. For the F 1/S/F 2 

and F 1/F 2/S asymmetrical trilayers the triplet superconducting component is generated 

at noncollinear magnetizations of the F layers. Assuming that all S and F layers are 

dirty we solve boundary problem for the Usadel function. The results of numerical 

calculations for Tc as function thicknesses both F 1 and F 2 layers at various parameters 

F/S structure are resented. The application to the spin-switch problem is discussed. We 

found that asymmetry can essentially change the spin-switch observation condition. 

Influence of proximity effect with Umklapp processes on the Josephson 

current in the SFS nanostructure 

Vadim Tumanov and Yurii N. Proshin* 


We consider the Josephson effect in symmetric superconductor-ferromagneticsuperconductor 

(SFS) system. The Josephson current is calculated as a function of the 

ferromagnetic layer thickness d. The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairs 

in the F layer have a nonzero wave vector, and the transformation the BCS pairs to the 

FFLO pairs (and vice versa) at passing through SF (FS) borders may be proceeded 

through the Umklapp processes [1]. To estimate the influence of proximity effect 

we use the expansion of superconductor energy in the powers of an order parameter 

(near the critical temperature Tc). We take into account the dependence of the critical 

temperature Tc from the phase difference φ between the order parameter in the left and 

right S side of the SFS contact. Our results are compared with known data for the Nb/ 

CuNi/Nb nanostructures [2] where the critical Josephson current oscillations due to 

transitions between 0 and π phase state were observed. A good agreement is obtained 

by taking into account the Umklapp processes. 

1. Yu. A. Izyumov, Yu. N. Proshin, and M. G. Khusainov, Physics/Uspekhi 45, 109 (2002) 2. V.V. 

Ryazanov et al., Rev. Low Temp. Phys. 136, 385 (2004) 


Poster Friday

Poster Friday 

SC27 


Superconducting characters under pressure in heavy fermion 

compounds CeIr(In 1-xCd x) 5 studied by In-NQR 

Mitsuharu Yashima 

Engineering Science, Osaka University, Japan 

The heavy fermion compounds CeMIn 5 (M = Co, Rh, Ir) have provided to study the 

relationship between antiferromagnetism and superconductivity. CeCoIn 5 becomes 

superconducting with $T_c$ = 2.3 K at ambient pressure1. This value is the highest 

record in the Ce-based heavy fermion superconductors. Since the existence of 

antiferromagnetic spin fluctuations is confirmed, it is expected that superconductivity 

is induced by antiferromagnetic spin fluctuations in CeCoIn 5. CeRhIn 5 is an 

antiferromagnet with $T_N$ = 3.8 K at ambient pressure. Taking into account the 

lattice parameters of CeIrIn 5, it is speculated that an antiferromagnetic order is realized 

at ambient pressure, but it actually shows superconductivity with $T_c$ = 0.4 K. 

The value of $T_c$ is very low, as compared with the other CeMIn 5 compounds. 

$T_c$ increases with increasing pressure and reaches about 1 K around 3 GPa, but 

antiferromagnetic spin fluctuations are greatly suppressed with the application of 

pressure. These results suggest that the superconducting mechanism of CeIrIn 5 may be 

quite different from that of the other CeMIn 5 compounds. In order to investigate the 

unconventional superconducting characteristics in CeIrIn 5, the nuclear-quadrupoleresonance 

(NQR) measurements were performed under pressure in pure and Cd-doped 

CeIrIn 5. 

SD01 

Giant and twofold oscillations of magnetoresistance in topological 

insulators Sb 2Te 3 and Bi 2Te 3 single crystals 

Zengji Yue, Xiaolin Wang* and Shixue Dou 

Spintronic and Electronic Materials Group, Institute for Superconducting & 

Electronic Materials, University of Wollongong NSW 2522,, Australia 

Topological insulators are quantum materials with an insulating bulk state and a topologically protected 

two dimensional metallic surface states.1,2 Unique electronic properties, such as the quantum spin Hall 

effect, magnetoelectric effects, magnetic monopoles, and elusive Majorana states, are expected from 

topological insulators.3,4 Topological insulators have great potential applications in spintronics and quantum 

information processing, as well as magnetoelectric devices with higher energy efficiency.5,6 To understand 

the macroscopic properties of the topological surface states and to investigate the possibility of their device 

applications, transport and magnetic measurements of high-quality single crystals are indispensable. 

Anisotropic magneto-transport properties were studied in p-type Sb 2Te 3 and n-type Bi 2Te 3 topological 

insulators through angular dependent magnetoresistance (MR) measurements. Giant MR of up to 230% was 

observed, which exhibits linear at high fields without any trend towards saturation. The giant MR displays 

a strong anisotropy, up to 210%, and twofold symmetry at different temperatures and fields. The giant MR 

might be due to intravalley and intervalley scattering, and the strong anisotropy might result from anisotropies 

of Fermi surface. The observed giant anisotropic MR of the Sb 2Te 3 and Bi 2Te 3 topological insulators could 

find applications in magneto-electronic devices based on topological insulators, such as magnetic sensors. 

1. M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 4 (2010). 2. X. L. Qi and S. C. Zhang, Rev. Mod. 

Phys. 83, 1057 (2011). 3. B. A. Bernevig, T. L. Hughes, and S. C. Zhang, Science 314, 1757 (2006). 4. D. 

Hsieh, D. Qian, L. Wray, Y. Xia, Y. S. Hor, R. J. Cava, and M. Z. Hasan, Nature 452, 970 (2008). 5. J. E. 

Moore, Nature 464, 194 (2010) 6. X. L. Wang, S. X. Dou, and C. Zhang, NPG Asia Mater. 2, 31 (2010). 

SD02 

Engineering and manipulating topological qubits in 1D quantum wires 

Panagiotis Kotetes 1 , Alexander Shnirman 2 and Gerd Schon 1 

1 

Institut fur Theoretische Festkorperphysik, Karlsruhe Institute of Technology, 

Germany 

2 

Institut fur Theorie der Kondensierten Materie, Karlsruhe Institute of Technology, 

Germany 

UPGRADED 


SD03 

Angle dependence of the Landau level spectrum in twisted bilayer 

graphene 

Min-young Choi, Young-hwan Hyun and Yoonbai Kim* 

Department of Physics, Sungkyunkwan University, Korea 

In the context of the low-energy effective theory, the exact Landau level spectrum 

of quasiparticles in twisted bilayer graphene with small twist angle is analytically 

obtained by spheroidal eigenvalues. We analyze the dependence of the Landau levels 

on the twist angle to find the points where the twofold degeneracy for twist angles 

is lifted in the nonzero modes and below (above) which massive (massless) fermion 

pictures become valid. In the perpendicular magnetic field of 10 tesla, the degeneracy 

is removed at approximately 3 degrees for a few low levels, specifically approximately 

2.56 degrees for the first pair of nonzero levels and approximately 3.50 degrees for 

the next pair. Massive quasiparticle appears at the angle less than 1.17 degrees in 10 

tesla, which matches perfectly with the recent experimental results. Since our analysis 

is applicable to the cases of arbitrary constant magnetic fields, we make predictions 

for the same experiment performed in arbitrary constant magnetic fields. For example, 

for 40 tesla we get the critical angle of 2.34 degrees and the sequence of angles 

5.11,7.01,8.42,... for the pairs of nonzero energy levels. The symmetry restoration 

mechanism behind the massive (massless) transition is conjectured to be a tunneling 

(instanton) in momentum space. 

SD04 

Surface band structure study of Bismuth-based ternary topological 

insulators 

Madhab Neupane 1 , S.-y. Xu 1 , C. Liu 1 , L. A. Wray 2 , N. Alidoust 1 , A. Fedorov 3 , Y. S. 

Hor 4 , T.-r Chang 5 , H.-t. Jeng 6 , H. Lin 7 , B. Bansil 7 , R. J. Cava 4 and M. Z. Hasan 1 

1 

Physics, Princeton University, USA 

2 

Physics, Princeton University & ALS, Berkeley, USA 

3 

Physics, ALS, Berkeley, USA 

4 

Chemistry, Princeton University, USA 

5 

Physics, National Tsing Hua University,, China 

6 

Physics, National Tsing Hua University & Institute of Physics, Academia Sinica,, 

China 

7 Physics, Northeastern University, USA 

Utilization of topological surface states is expected to lead to new vistas in electronics 

and fundamental physics. However, most of the known topological insulators either do 

not feature necessary band structure conditions (location of Dirac point with respect to 

the bulk band) or lack topological invariants essential for certain class of applications. 

Using angle-resolved photoemission spectroscopy (ARPES), we reveal the electronic 

band structure topology of a family of ternary spin-orbit insulators some of which 

feature functional electronic structure with in-gap Dirac point while others feature 

novel topological invariants (weak Z 2 invariants) in crystalline form. These Bi-based 

ternary topological insulators provide a natural access to lattice matched magnetically 

ordered states to be utilized in future devices. 

SD05 

Topological aspects and transport properties of edge states in the 

multi-band superconductor Sr2RuO4 Yoshiki Imai 1 *, Katsunori Wakabayashi 2 and Manfred Sigrist 3 

1 

Department of Physics, Saitama University, Japan 

2 

<strong>International</strong> Center for Materials Nanoarchitectonics, National Institute for 

Materials Science, Japan 

3 

Theoretische Physik, Eidgenossische Technische Hochschule Zurich, Switzerland 

Motivated by the spin-triplet chiral p-wave superconductor Sr 2RuO 4, we investigate 

the edge state of multi-band superconductor by means of the three band tight-binding 

model including inter-orbital hybridization and spin-orbit coupling effects. These bands 

correspond to the alpha, beta and gamma bands of Sr 2RuO 4 where alpha and beta bands 

have hole- and electron-like characters, respectively. In particular we focus on the 

topological aspects and transport properties in the chiral spin-triplet phase. Although 

a full quasiparticle excitation gap in the bulk system, gapless edge states appear and 

affect both spontaneous spin and charge currents which give rise to anomalous and 

spin Hall effect. In this context, we study the interplay between electron- and hole-like 

particles and the effect of the genuinely two-dimensional gamma band in the formation 

of these edge states and edge currents. The topological aspects and correlation effects 

on this system are also discussed.

SD06 

Influence of geometry on the edge states of Bi Nanoribbons 

Hyun-jung Kim 1 , Gustav Bihlmayer 2 , Stefan Bluegel 2 and Jun-hyung Cho 1 * 

1 

Department of Physics and Research Institute for Natural Sciences, Hanyang 


2 

Peter Gruenberg Institut and Institute for Advanced Simulation, Forschungszentrum 

Juelich and JARA, Germany 

Two-dimensional (2D) topological insulators or 2D quantum spin Hall (QSH) systems 

provide an intriguing physical phenomena in condensed matter physics. The 2D QSH 

phase is a band insulator but has gapless edge states. The salient feature of these edge 

states is that they are topologically protected. Here, using first-principles densityfunctional 

calculations, we investigate the effect of geometry on the edge states in zigzag 

Bi nanoribbon (ZBNR) reported as a 2D QSH system.[1] We consider various edge 

geometries involving the ideal termination, relaxation, and rebonded reconstruction. We 

find that the rebonded reconstruction geometry is thermodynamically more stable than 

other geometries. Since the transition from the reconstruction to the relaxation geometry 

is kinetically feasible, the edge structure of ZBNR is expected to exhibit the orderdisorder 

transition as a function of temperature. We also find that the metallic feature 

of edge states is preserved with respect to the shear distortion and bond alternation, 

but it is dramatically altered to produce a band-gap opening through the rebonded 

reconstruction. We discuss such an influence of geometry on the edge states of ZBNR in 

terms of the penetration depth of the edge states. 

[1] M. Wada, S. Murakami, F. Freimuth, and G. Bihlmayer, Phys. Rev. B 83, 121310(R) (2011). 

SD07 

Magnetotransport measurements in pulsed magnetic fields: a case for 

Fermiology studies in superconductors and topological insulators 

Frederik Wolff-fabris 1 *, Jun Sung Kim 2 , Erik Kampert 1 , Joonbum Park 2 , Man Jim 

Eom 2 , Sergei Zherlitsyn 1 , Thomas Herrmannsdoerfer 1 and Jochen Wosnitza 1 

1 Dresden High Magnetic Field Laboratory (HLD), HZDR, Germany 

2 Department of Physic, Pohang University of Science and Technology, Korea 

Superconductors and Dirac materials, such as graphene and topological insulators, are intensively 

studied in high magnetic fields. In this work, we present the current status of magnetotransport 

measurements at the Dresden High Magnetic Field Laboratory (HLD) and discuss examples of 

phase-diagram and fermiology investigations in different compounds [1,2], as well as the new 

Dirac material [3] SrMnBi 2. Typical experiments in magnetic fields up to 85 T with 25 to 150 ms 

pulse duration in samples spaces up to 16 mm are performed by discharging a 50 MJ capacitor 

bank. We use standard four-probe-technique measurements with AC currents up to 200 kHz and 

the longitudinal and transverse (Hall effect) voltages signals from the samples are digitized with a 

fast recording system. We observed quantum oscillations in magnetotransport measurements up 

to 63 T on crystals of SrMnBi 2 and, together with other techniques, this demonstrates that there 

is a Dirac dispersion in the electronic structure of the double-sized Bi square net. However, in 

contrast to graphene, the Dirac cone in SrMnBi2 is highly anisotropic which suggests that the Bi 

square net can provide a new platform for highly anisotropic Dirac fermions. Aknowledgements 

Work at the HLD was supported by EuroMagNET II (No. 228043). 

[1] V. A. Gaparov, F. Wolff-Fabris, D. L. Sun et al. JETP 93, v.1, p. 29 (2010); [2] M. V. Kartsovnik, T. Helm, K. Putzke et al. 

New Journal of Physics 13, 015001 (2011); [3] J. Park, G. Lee, F. Wolff-Fabris et al. Physical Review Letters 107, 126402 (2011). 

SD08 

First-principles study of spin texture in the multilayer graphene on 

Ni(111) 

Fumiyuki Ishii 1 *, Hiroki Kotaka 2 , Keisuke Sawada 3 and Mineo Saito 1 



3 Graduate School of Natural Science and Technology,, Kanazawa University, Japan 

MOVED 

SD09 

SD10 

Magnetic properties of rare earth doped Bi 2Te 3 

Nahyun Jo, Youngha Choi, Kyujoon Lee and Myung-hwa Jung* 

Physics, Sogang University, Korea 

SD11 


A full quantum study on gapless modes and Axion electrodynamics in 

topological insulator heterostructure systems 

Ken Shiozaki 1 *, Takahiro Fukui 2 and Satoshi Fujimoto 1 

1 Depertment of Physics, Kyoto University, Japan 

2 Depertment of Physics, Ibaraki University, Japan 

Three dimensional topological insulator heterostructure systems show the various novel phenomena 

such as gapless modes localized at defects or the Axion response in three dimensional topological 

insulator-magnetic insulator heterostructures. The origin of these phenomena is the nontrivial 

topology in both momentum and real spaces. Dealing with the spatial coordinates as the adiabatic 

parameter in the heterostructure systems, one can introduce the semiclassical Hamiltonian, which 

describes topological properties of the heterostructure system. On the other hand, in some cases, 

it also happens that semiclassical approaches fail to describe correctly topological features. In this 

study, we present full quantum treatment for three dimensional topological insulator heterostructure 

systems without the semiclassical approximation. We, first, prove the index theorem for gapless 

modes in line defects of the topological insulator-magnetic insulator heterostructure systems. 

Secondly, we demonstrate a full quantum calculation for the surface quantum anomalous Hall 

effect at the interface of the topological insulator-magnetic insulator heterostructure without using 

the Axion effective action. We also show that gapless modes in line defects and the Axion response 

may be governed not only by helical Dirac fermions on the surfaces, but also by gapped bound 

states at the interface, the contribution of which was missed in previous studies. 

Xiao-Liang Qi, Taylor L. Hughes, and Shou-Cheng Zhang, Phys. Rev. B 78, 195424 (2008). Jeffrey C. 

Y. Teo and C. L. Kane, Phys. Rev. B 82, 115120 (2010). 

Bi 2Te 3 is one of 3-dimensional topological insulators together with Bi 2Se 3 and Bi 2Sb 3. 

[1] Recently, Binghai Yan et. al have theoretically reported that LaBiTe 3 is a strong 

topological insulator. [2] We could conjecture that rare-earth materials have fascinating 

magnetic properties, since it has filled outer shell ( 5s25p6 ) and simulataneously 

unfiled inner shell (4f n). [3] Therefore, we made both LaxBi 2-XTe 3 and CexBi 2-XTe 3, 

and measured transport and magnetic properties. LaxBi 2-XTe 3 is diamagnetic, while 

CexBi 2-XTe 3 is paramagnetic at low temperature. From the modified curie-wiess fit, 

we could obtain the effective magnetic moment of 2.56μB. This value demonstrates 

that the Ce ion is in trivalent state. However, the carrier density of CexBi 2-XTe 3 is 

observed to be on order smaller than that of Bi 2Te 3, giving rise to a strong increase 

of carrier mobility. These results support a scenario of strong topological insulator. 

Furthermore, a magnetoresistance ratio of CexBi 2-XTe 3 is 1600% at 70kOe, even 

though ferromagnetic FexBi 2-XTe 3 have 600% magnetoresistance ratio at 70kOe. 

[1] Y.L. Chen et. al., SCIENCE, 325, 178 (2005) . [2] Binghai et. al. PRB, 82, 161108(R) (2010). [3] 

Charles Kittel, Introduction to Solid State Physic (John Wiley & Sons, Inc, New Jersey, 2005 ) . 

Iron doping effect in topological insulator: Bi 2Te 3 

Nahyun Jo 1 , Youngha Choi 1 , Kyujoon Lee 1 , Jungwon Jang 2 , Jinhee Kim 2 , Akio 

Kimura 3 and Myung-hwa Jung 1 * 

1 Physics, Sogang University, Korea 

2 Korea Research of Standards and Science, Korea 

3 Physics, Hiroshima University, Japan 

Bi 2Te 3 is well-known topological insulator with anti-site defects which complicates 

the manipulation of the Fermi level. It has also been reported that surface band of 

topological insulators is open when magnetic ions are doped, because magnetic ions 

are able to break the time reversal symmetry. In this report, we doped magnetic ions 

of Fe into Bi 2Te 3 and studied the properties and the corresponding electronic structure. 

We found that a small amount of Fe ions less than 0.4% do not open the surface gap, 

but reduce the anti-site defects. Thus, Fe-doped Bi 2Te 3 has linear magnetoresistance 

with high mobility (15,074cm2v-1s-1) which is three times higher than Bi 2Te 3 while 

Bi 2Te 3 has a deviation from the linear dependence of magnetoresistance. The reduction 

of anti-site defects enhances the sample quality, so that we could observe quantum 

oscillations such as Shubnikov de Haas and de Haas van Alphen effect. In addition, 

the spin-dependent ARPES data also demonstrate both clear surface state without gap 

opening and canted spin components in the c axis. 


Poster Friday

Poster Friday 

SD12 


Magneto transport properties of topological insulator nanoribbons of 

Bi2Te3 Hong-seok Kim 1 , Hosun Shin 2 , Eun-kyoung Jeon 3 , Kung-won Rhie 1 , Ju-jin Kim 4 , 

Jeong-o Lee 3 , Jaeyong Song 2 and Yong-joo Doh 1 * 

1 

Dept. of Display and Semiconductor Physics, Korea University Sejong Campus, 

Korea 

2 


3 

Korea Research Institute of Chemical Technology, Korea 

4 

Dept. of Physics, Chonbuk National University, Korea 

We report on the magneto transport properties of topological insulator nanoribbons 

of Bi 2Te 3. The Bi 2Te 3 nanoribbons were grown using the electrodeposition processes 

and contacted with 100-nm-thick cobalt electrodes. At low temperature below T = 

10 K, the magnetoreistance increases with a magnetic field, B, which is attributed 

to a weak antilocalization effect. When the magnetic field (B) is applied parallel 

to the ferromagnetic electrodes on top of the nanoribbon, a switching behavior of 

the magnetoresistance is observed near B = 400 Oe. Temperature and gate voltage 

dependences of the spin valve effect is discussed as well. 

SD13 

Structural investigations of the topological insulators Bi 2Se 3-xTex 

Geetha Balakrishnan 1 *, Ravi Singh 1 , Devashibhai Adroja 2 , Kevin Knight 2 and 

Matthias Gutmann 2 

1 Department of Physics, University of Warwick, United Kingdom 

2 ISIS Facility, Rutherford Appleton Laboratory, United Kingdom 

The binary phases Bi 2Se 3 and Bi 2Te 3 have been discovered to exhibit three dimensional 

topological insulating behaviour. However, these compounds are not insulators when 

investigated in the bulk. Bi 2Se 3 is generally known to exhibit n-type conductivity 

and Bi 2Te 3 exhibits n or p-type conductivity depending on the synthesis conditions. 

The bulk conductivity exhibited by these materials are seen as being detrimental 

to the investigation of their surface conducting properties. We have examined the 

intermediate compositions Bi 2Se 3-xTex in order to study the role played by vacancies 

and anti-site defects in determining the bulk conduction mechanisms. We report 

detailed structural refinements obtained by neutron diffraction experiments on several 

of the intermediary phases and draw correlations between the defect structures and 

their conducting / semiconducting / insulating behaviour. 

SD14 

Josephson effects in Bi 2Se 3 topological insulator nanoribbons 

Hyunho Noh 1 , Lee-seul Park 2 , Eun-kyoung Jeon 3 , Hong-seok Kim 4 , Jeong-o Lee 3 , Jin 

Seok Lee 2 , Jinhee Kim 1 and Yong-joo Doh 4 * 


2 Dept. of Chemistry, Sookmyung Women’s University, Korea 

3 Korea Research Institute of Chemical Technology, Korea 

4 Dept. of Display and Semiconductor Physics, Korea University Sejong Campus, 

Korea 

Topological insulators are exotic materials with bulk band gap and metallic edge 

states which are protected on their own boundary topologically. Here, we report on 

the fabrication and measurement results of the superconducting proximity junctions 

of topological insulator nanoribbons of Bi 2Se 3. Single-crystalline Bi 2Se 3 nanoribbons 

are synthesized using the vapor-liquid-solid method, while the superconducting Al 

electrodes are formed on top of the nanowire. When a magnetic field (H) is applied 

along the axial direction, the magneto-resistance data exhibit quasi-periodic oscillations 

with an average periodicity of H* ~ 0.4 T, which is consistent with the Aharonov- 

Bohm oscillations. In the superconducting state, the supercurrent branch with a critical 

current of Ic ~ 90 nA is clearly observed in the current-voltage curve as a result of the 

superconducting proximity effect in Bi 2Se 3 nanoribbon. Quantized voltage steps of the 

Bi 2Se 3 nanoribbon Josephson junction under the microwave irradiation satisfy the ac 

Josephson relation. 


SD15 

Electronic structure and transport properties of pt based heusler 

compounds with C1b structure for topological quantum phenomena 

Siham Ouardi 1 , Gerhard H. Fecher 1 , Shekhar Chandra 2 , Gloskovskii Andrei 3 and 

Felser Claudia 1 

1 

Johannes Gutenberg University and Max Planck Institute for Chemical Physics of 

Solids, Dresden, Germany 

2 


3 

Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 

Mainz, Germany 

Many of the Heusler compounds based on heavy elements with 1:1:1 composition and C1b structure are zero 

band gap insulators and exhibit partially an inverted band structure [1]. Based on a topologically protected 

electronic surface states, this class of materials is supposed to open up innovative directions for future 

technological applications in spintronics, quantum computing and thermoelectrics. The density of states of Pt 

based Heusler compounds PtMZ (M = Y, Gd, Lu and Z= Sb, Bi) were investigated by bulk sensitive hard X-ray 

photoelectron spectroscopy. The measured valence band spectra are clearly resolved and in well agreement with 

the first-principles calculations of the electronic structure of the compounds. Close to the Fermi energy, the linear 

behavior of the measured spectra at high excitation energy where influences of the surface can be neglected 

improve bulk origin of the Dirac-cone type density [2]. Furthermore, the temperature dependence of electrical 

conductivity, Hall mobility, Seebeck coefficient and thermal conductivity were investigated. The promising 

properties of those compounds open a high potential for new technological applications. 

[1] S. Chadov, X. Qi, J. Kubler, G. H. Fecher, C. Felser, and S. Zhang, Nat Mater 9, 541 (2010). [2] S. Ouardi, C. Shekhar, G. 

H. Fecher, X. Kozina, G. Stryganyuk, C. Felser, S. Ueda, and K. Kobayashi, Appl. Phys. Lett. 98, 211901 (2011). 

SD16 

Gapless interface states in topological insulator/semiconductor 


Hugo Aramberri and Carmen Munoz* 

ICMM- Consejo Superior de Investigaciones Cientificas, Spain 

Based on first principles calculations we investigate the existence of topologicallynontrivial 

states at the interface between a topological insulator (TI) and a 

semiconductor (S) in TI/S heterostructures. We find that the emergence of gapless states 

depends on the symmetry of the junction, being protected by mirror symmetry. We 

discuss their characteristic dispersion and spatial distribution and analyze the quantum 

interference between helical states and its influence on the spin texture of the quasi 

two-dimensional states as a function of the semiconductor thicknesses. From the firstprinciples 

calculations, we derive an effective Hamiltonian, which captures the salient 

topological features. The effective model combined with a Green function matching 

method [1] allow us to investigate the evolution of the interaction between interface 

helical Dirac fermions from finite heterostructures to actual seminfinite interfaces and 

therefore to analyze the novel behavior of the spin-charge coupling in two-dimensional 

layered systems with strong spin-orbit coupling. 

[1] M. C. Munoz, V. R. Velasco and F. Garcia-Moliner, Phys. Rev. B. 39 (1989) 1786; M. C. Munoz 

and M. P. Lopez Sancho, Phys. Rev. B. 41 (1990) 8412. 

SD17 

Thermoelectric transport in topological insulators 

Oleg Tretiakov* 

Physics and Astronomy, Texas A&M University, USA 

We study the thermoelectric properties of three-dimensional topological insulators 

with many holes (or pores) in the bulk. We show that at high density of these holes 

the thermoelectric figure of merit, ZT, can be large due to the contribution of the 

conducting surfaces and the suppressed phonon thermal conductivity. The maximum 

efficiency can be tuned by an induced gap in the surface states dispersion through 

tunneling, magnetic impurities, or external magnetic fields. The large values of ZT, 

much higher than unity for reasonable parameters, make this system a strong candidate 

for applications in heat management of nanodevices, especially at low temperatures. 

O. A. Tretiakov, Ar. Abanov, and Jairo Sinova, Applied Physics Letters, 99, 113110 (2011).

SD18 

Topological phase in a one-dimensional interacting fermion system 

Huaiming Guo 

Department of physics, Beihang University, China 

We study a one-dimensional (1D) interacting topological model by means of the 

exact diagonalization method. The topological properties are first examined with the 

existence of the edge states at half-filling. We find that the topological phases are not 

only robust to small repulsive interactions, but also are stabilized by small attractive 

interactions, and also finite repulsive interaction can drive a topological nontrivial 

phase into a trivial one while the attractive interaction can drive a trivial phase into a 

nontrivial one. Next we calculate the Berry phase and parity of the bulk system and 

find that they are equivalent in characterizing the topological phases. With them we 

obtain the critical interaction strengths and construct part of the phase diagram in the 

parameters’ space. Finally we discuss the effective Hamiltonian at the large-U limit and 

provide an additional understanding of the numerical results. These results could be 

realized experimentally using cold atoms trapped in the 1D optical lattice. 

1: Xiao-Liang Qi and Shou-Cheng Zhang, Rev. Mod. Phys. 83, 1057 (2011). 2: J. E. 

Moore, Nature (London) 464, 194 (2010). 3: M. Z. Hasan and C. L. Kane, Rev. Mod. 

Phys. 82, 304 (2011). 4: Huaiming Guo and Shun-Qing Shen, Phys. Rev.B 84, 195107 

(2011). 

SD19 

Robustness of 1D topological superconductors with Majorana edge 

states against lattice modulation 

Masaki Tezuka* and Norio Kawakami 

Department of Physics, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, 

Japan 

SE01 

UPGRADED 

Temperature-pressure phase diagram of quadrupolar order in 

PrTr 2Al 20 (Tr=Ti,V) 

Toshiki Tanaka 1 , Kazuyuki Matsubayashi 2 *, Akihiko Hisada 2 , Akito Sakai 2 , Satoru 

Nakatsuji 2 , Yoshiya Uwatoko 2 and Yasunori Kubo 3 

1 Graduate School,Nihon Univ, Japan 


3 College of Humanities and Sciences,Nihon Univ, Japan 

PrTr 2Al 20 (Tr=Ti,V) crystallizes in a cubic CeCr 2Al 20 type structure with the space group Fd 3 

?m. According to neutron experiment, crystal electric field (CEF) ground state of Pr ion is the 

non-Kramers Γ 3 doublet [1]. Reflecting the non-magnetic ground state, PrTi 2Al 20 and PrV 2Al 20 

exhibit quadrupolar ordering at TQ ~ 2.0 K and 0.6 K, respectively. It is notable that the low 

temperature electrical resistivity of PrV 2Al 20 shows √T dependence, suggesting the quadrupolar 

Kondo effect[2]. In the present study, we have measured electrical resistivity under high 

pressure on PrTr 2Al 20 (Tr=Ti,V) single crystals in order to clarity the pressure dependence of TQ 

and Kondo effect. Electrical resistivity of PrTi 2Al 20 shows the broad maximum centered at ~50 

K due to incoherent Kondo-scattering processes on the ground state and the excited CEF level. 

With increasing pressure, the magnitude of this anomaly increases while the peak position is 

unchanged. At lower temperatures, it is found that a clear resistive drop at TQ ~ 2 K at ambient 

pressure. TQ first increases and shows the maximum under pressure. We will present the phase 

diagram of PrTi 2Al 20 together with that of PrV 2Al 20. 

[1]:T. J. Sato, S. Ibuka, A. Sakai and S. Nakatsuji: Meeting Abst. Phys. Soc. Jpn,Vol.65, Issue 2, Pt. 3, 

(2010) p. 584 [2]:A.Sakai, S.Nakatsuji : J. Phys. Soc Jpn. 80 (2011) 063701 

SE02 

SE03 

SE04 


Soft point contact spectroscopy in the antiferromagnet Ce 2RhIn 8 

Eunsung Park 1 , Xin Lu 2 , Chung Jae Won 3 , Nam Jung Hur 3 , Eric D. Bauer 2 , Joe D. 

Thompson 2 and Tuson Park 1 * 

1 Department of Physics, Sungkyunkwan University, Korea 

2 Condensed Matter & Magnet Science Group, Los Alamos National Laboratory, USA 


We performed soft point contact spectroscopy on the Ce-based heavy fermion systems 

(CeIn 3, CeCoIn 5, CeRhIn 5, CeIrIn 5, and Ce 2RhIn 8) with silver epoxy replacing a 

conventional tip. Unlike CeIn 3 where the conductance dI/dV is enhanced below TN 

(=10K), the conductance of CeRhIn 5 at zero bias voltage is rapidly enhanced below 

8K, which is higher than TN of CeRhIn 5 (=3.8K). Heavy fermion compounds with 

a magnetic order often show intermediate states that are characterized by a broad 

enhancement of conductance at temperatures higher than TN, while heavy fermion 

compounds without magnetic ordering reveal asymmetric conductance line-shape 

below characteristic temperature T*. The antiferromagnet Ce 2RhIn 8 is unique in that 

the intermediate state shows a V-shaped dip around zero biased voltage and is enhanced 

with decreasing temperature below 25K, which is much higher than T*=5K. Below 

TN=2.8K, a symmetric peak at zero bias voltage in the conductance spectra is enhanced 

within the V-shaped dip with decreasing temperature. We interpret the symmetric peak 

and V-shaped dip around zero bias as manifestation of the antiferromagnetic (AFM) 

order and Kondo dip in the Kondo lattice system, respectively, indicating that Ce 2RhIn 8 

is at a boundary between AFM and Kondo states. 

Evidence of a spin gap above the magnetic ordering temperature and 

crystal field excitations in CeOs2Al10 D T Adroja 1 *, P P Deen 2 , A D Hillier 1 , Y Muro 3 , J Kajino 4 , T Takabatake 4 , A M 

Strydom 5 , P Peratheepan 5 , F Demmel 1 , J R Stewart 1 and J Taylor 1 

1 

ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom 

2 

European Spallation Source, St Algatan 4, Box 176 Lund 221 00, Sweden 

3 

Liberal Arts and Sciences, Toyama Prefectural University, Kurokawa 5180, Imizu 939-0398, Japan, Japan 

4 

Department of Quantum matter, ADSM, and IAMR, Hiroshima University, Higashi-Hiroshima, 739-8530, 

Japan, Japan 

5 

Physics Department, University of Johannesburg, PO Box 524, Auckland Park 2006, South Africa, South 

Africa 

Recently, the opening of a spin gap has been reported in the intermetallic compounds CeT 2 Al 10 (T = Ru 

and Os) below TN = 27-29K through heat capacity and magnetic susceptibility measurements. Various 

theoretical models have been proposed to explain the spin gap formation, for example a spin-Peierls and 

RVB models of Hanzawa for CeRu 2Al 10. To understand the nature of the spin gap formation in CeOs 2Al 10, 

we have carried out low and high energies inelastic neutron scattering (INS) measurements between 4.5 and 

65K. Our INS studies reveal a clear sign of a spin gap of 11meV at 4.5K and of 4meV at 35K, while above 

45K the observed response transformed into a quasielastic line with linewdith of ~ 8 meV. The observation 

of a spin gap above TN suggests that its origin is not only due to the gapped spin wave, but also related to 

the hybridization between 4f- and conduction electrons. Moreover the high energy INS study reveals two 

crystal field (CEF) excitations at 37 and 57meV. We have carried out an analysis of the INS data along with 

the single crystal susceptibility based on the CEF model, which gives good fit to both data sets. 

Role of quantum fluctuations in forming heavy-fermions for Ca2 xSrxRuO4 Naoya Arakawa and Masao Ogata 

Department of Physics, The University of Tokyo, Japan 

In order to understand a role of quantum fluctuations in forming heavy-fermions 

for Ca 2-xSrxRuO 4, we investigated the effect of quantum fluctuations on the massenhancement 

on the basis of the three-orbital Hubbard model for the Ru-t2g-orbitals. 

In this presentation, I show the momentum-dependence of both the spin and charge 

susceptibilities for the tight-binding models at x = 2.0 and 0.5 within the random 

phase approximation (RPA). I also present the variation of γe, obtained by using the 

Hellmann-Feynman theorem and the RPA, between x=2.0 and 0.5 and address a role of 

both the spin and orbital fluctuations in enhancing γe for Ca 2-xSrxRuO 4. 


Poster Friday

Poster Friday 

SE05 


Specific heat of structure-disordered heavy-fermion Ce xY 80-xMn 20 

alloys 

Yusuke Amakai 1 *, Shinya Tanaka 1 , Yasuhiro Shiojiri 1 , Naoki Momono 1 , Hideaki 

Takano 1 , Shigeyuki Murayama 1 , Yoshihisa Obi 2 and Koki Takanashi 2 


2 Institute for Material Research, Tohoku University, Japan 

Recently, we have reported physical properties of structure-disordered (a-)Ce xY 80-xMn 20 

alloys which show a heavy fermion state in the non-Bloch system without translation 

symmetry[1]. The specific heat Cp for present alloys follows γT + βT3 down to 

about 10 K. The T-linear coefficient γ shows a large value (~200 mJ/Ce-molK 2) and 

almost independent of the Ce-concentration. However, the Cp/T vs. T2 plot of T < 

10 K deviates from the T-linear relation with decreasing temperature. In this work, in 

order to clarify the factor of the deviation of Cp/T for a-Ce xY 80-xMn 20 alloys, we have 

measured the low-temperature specific heat. We have estimated the temperature TA of 

the deviation from the Cp/T vs. T 2 plot for present alloys. The TA is about 10 K, and 

almost independent of the Ce-concentration. Therefore, the deviation from the Cp/T 

for the present alloys would be considered the crystalline-electric-field splitting of the 

six-fold degenerate level of the Ce 3+ ion. Detailed discussions will be presented at the 


[1] Y. Amakai, et. al., Phys. Rev. B, 79(2009)245126. 

SE06 

Specific heat of structure-disordered heavy-fermion CexY 80-xMn 20 

alloys 

Yusuke Amakai 1 *, Shinya Tanaka 1 , Yasuhiro Shiojiri 1 , Naoki Momono 1 , Hideaki 

Takano 1 , Shigeyuki Murayama 1 , Yoshihisa Obi 2 and Koki Takanashi 2 


2 Institute for Material Research, Tohoku University, Japan 

Recently, we have reported physical properties of structure-disordered (a-)CexY 80xMn 

20 alloys which show a heavy fermion state in the non-Bloch system without 

translation symmetry[1]. The specific heat Cp for present alloys follows γT + βT3 

down to about 10 K. The T-linear coefficient γ shows a large value (~200 mJ/CemolK 

2) and almost independent of the Ce-concentration. However, the Cp/T vs. T2 

plot of T < 10 K deviates from the T-linear relation with decreasing temperature. In 

this work, in order to clarify the factor of the deviation of Cp/T for a-CexY 80-xMn 20 

alloys, we have measured the low-temperature specific heat. We have estimated the 

temperature TA of the deviation from the Cp/T vs. T 2 plot for present alloys. The TA is 

about 10 K, and almost independent of the Ce-concentration. Therefore, the deviation 

from the Cp/T for the present alloys would be considered the crystalline-electric-field 

splitting of the six-fold degenerate level of the Ce 3+ ion. Detailed discussions will be 

presented at the conference. 

[1] Y. Amakai, et. al., Phys. Rev. B, 79(2009)245126. 

SE07 

Synchrotron X-ray diffraction study on crystal structure of URu2Si2 Chihiro Tabata 1 *, Reiji Kumai 2 , Kensuke Kobayashi 2 , Hironori Nakao 2 , Yoichi 

Murakami 2 , Makoto Yokoyama 3 , Hiroyuki Hidaka 1 , Tatsuya Yanagisawa 1 and Hiroshi 

Amitsuka 1 

1 

Graduate School of Science, Hokkaido University, Japan 

2 

CMRC and PF, Institute of Materials Structure Science, High Energy Accelerator 

Research Organization, Japan 

3 

Faculty of Science, Ibaraki University, Japan 

URu 2Si 2 (the tetragonal ThCr 2Si 2 type crystal structure; space group I4/mmm) has 

attracted much interest because of its peculiar phase transition at 17.5 K (≡To) [1- 

3]. Despite more than 25 years of intense research trying to identify the order 

parameter, the intrinsic nature of the phase transition has not been elucidated [4]. The 

ThCr 2Si 2 structure includes a free position parameter, z, of the Si 4(e) site. Since the 

Si ions are located at the second nearest-neighbor position of the U ions, the precise 

determination of the z parameter might provide useful information for evaluation of 

hybridization effects of 5f orbits with Si s, p states, calculations of a band structure, 

analyses for 29Si-NMR spectra, and so on. These pieces of knowledge might offer a 

clue to solving the issue of hidden order in URu2Si2. We will report our latest study 

of structural analyses of a single crystal of this material based on the X-ray diffraction 

measurements performed at BL-8A and B in the Photon Factory KEK. 

[1] T.T.M. Palstra et al., Phys. Rev. Lett. 55, 2727 (1985). [2] M.B. Maple et al., Phys. Rev. Lett. 56, 185 (1986). 

[3] W. Schlabitz et al., Z. Phys. B 62, 171 (1986). [4] J.A. Mydosh and P.M. Oppeneer, arXiv:1107.0258v1 (2011). 


SE08 

Spin-density wave order in the 2D heavy fermion system CePt 2In 7 

Martin Mansson 1 *, Jun Sugiyama 2 , Yasmine Sassa 1 , Bastian M. Wojek 3 , Thomasz 

Durakiewicz 4 , Krunoslav Prsa 1 , Olof Gotberg 3 , Calin Rusu 5 , Daniel Andreica 5 , 

Stephane Pons 6 , Marco Grioni 6 , Oscar Tjernberg 3 and Eric D. Bauer 4 



3 Materials Physics, Royal Institute of Technology, KTH Stockholm, Sweden 


5 Faculty of Physics, Babes-Bolyai University, Romania 

6 Institute of Condensed Matter Physics, EPF Lausanne, Switzerland 

The title compound is a recently discovered heavy fermion material where the spacing between Ce-In 

planes is drastically increased. Consequently, CePt 2In 7 inherit a truly 2D electronic structure. It was recently 

discovered that CePt 2In 7 is not only AF (TN=5.3 K) at ambient pressure but also becomes SC under 

pressure with a maximum transition temperature Tc=2.1 K at P=3.12 GPa. At lower pressures an intriguing 

coexistence of the AF order and SC phase is found, and that with increasing pressure Tc is increasing while 

TN decreases. The growth of the SC on the expense of the AF order suggests a crossover behavior of the Ce- 

4f electrons from localized to itinerant, similar to what is considered for the well-known CeRhIn 5 compound. 

In the presented work the low-temperature microscopic magnetic properties of the quasi-2D heavy fermion 

compound, CePt 2In 7 are investigated by using μSR. Clear evidence for the formation of a SDW order is 

presented. The magnetic order parameter fit well to a modified BSC gap-energy function in a strong-coupling 

scenario, possibly predicting the evolution of unconventional pairing in the pressure induced superconducting 

phase of this compound. Finally, we also present recent pressure dependent μSR data. 

Funding Source: Swiss National Science Foundation (Project 6, NCCR MaNEP), U.S. DOE Oce of 

Sciences, VR Sweden and Toyota CRDL. 

SE09 

Metal-nonmetal transition in Cr partial substituted Ni 0.96S 

Masanori Matoba*, Yoichi Kamihara and Shuichiro Anzai 

Center for Applied Physics and Physico-Informatics, Keio University, Japan 

Hexagonal NiAs-type NiS exhibits a first-order metal-nonmetal transition (MNT) at Tt=263K, 

resulting from the opening of narrow charge-transfer (CT) gap between the S 3p band and the 

upper Hubbard band [1,2]. The low temperature phase is the nonmetallic antiferromagnetic 

state, while the high temperature phase shows metallic and Pauli-paramagnetic behavior 

[3,4]. The substitution of vacancies for Ni atoms in NiS lowers Tt to be suppressed to be 

zero at d=0.035 in Ni 1-dS, so that metallic Ni 0.96S do not exhibit the MNT [5,6]. In this study, 

we synthesized Cr-partial substituted Ni 0.96S or (Ni 1-xCrx) 0.96S by a solid state reaction in an 

evacuated silica tube to reveal the Cr-partial substitution effect on the physical properties 

of metallic Ni 0.96S by the measurements of X-ray diffraction, electrical resistivity, magnetic 

susceptibility, and thermopower. Surprisingly, (Ni 1-xCrx) 0.96S clearly exhibits the MNT, while 

metallic Ni 0.96S do not exhibit the MNT. The Tt increases with x sharply from x=0.025 (Tt=50 

K) to x=0.09 (Tt=260 K) by Cr-partial substitution for Ni in Ni_{0.96}S. At the conference, 

electronic nature of Cr-partial substituted Ni 0.96S or (Ni 1-xCrx) 0.96S with ability for the opening of 

CT-gap will be discussed from the viewpoint of the strongly correlated electron systems. 

[1] A. Fujimori, H. Namatame, M. Matoba and S. Anzai, Phys. Rev. B 42, 620 (1990). [2] M. Imada, A. Fujimori, and Y. 

Tokura, Rev. Mod. Phys. 70, 1039 (1998). [3] J. T. Sparks and T. Komoto, Phys. Lett. A 25, 398 (1967). [4] S. Anzai 

and K. Ozawa, J. Phys. Soc. Jpn. 24, 271 (1968). [5] R. Brusetti, J. M. D. Coey, G. Czjzek, J. Fink, F. Gompf and H. 

Schmidt, J. Phys. F 10, 33 (1980). [6] M. Matoba and S. Anzai and A. Fujimori, J. Phys. Soc. Jpn. 60, 4230 (1991). 

SE10 

A study of ni-substitution and pressure effects on the heavy-fermion 

Superconductor CeCu 2Si 2 

Yoichi Ikeda*, Yuzo Ito, Shingo Araki and Tatsuo C Kobayashi 

Graduate School of Natural Science and Technology, Okayama University, Japan 

The heavy-fermion superconductor CeCu 2Si 2 shows an attractive enhancement of T_c 

around a critical pressure (~ 4.5 GPa), at which the T-linear variation of resistivity, the 

enhancement of the residual resistivity, the rapid decrease of T 2 -coefficient and a sign of 

a valence crossover have been observed [1-3]. These characteristics have been believed 

to be signatures of the critical valence fluctuations associated with a valence transition 

around its critical-end point [4, 5], while we have been requiring more signatures for 

clarification of the fascinating phenomena. Effects of the Ni substitution on CeCu 2Si 2 

are investigated by means of specific heat and electrical resistivity measurements. A 

characteristic T-linear dependence of the resistivity is observed around x ~ 0.1 with a 

fractional resistivity drop due to filamentary superconductivity. In addition, a variation 

of the power index n of a fit to ρ-ρ_0 = aT^n at low temperatures against T_1^max 

at which the resistivity shows a maximum is almost fully identical to the result of the 

high pressure experiment [1]. We would like to discuss for the similarities between Ni 

doping and pressure and the origin of the anomalous Fermi liquid state. 

[1] A. Holmes et al., PRB 69 (2004) 024508. [2] K. Fujiwara et al., submitted to J. Phys.: Conf. Ser. 

(SCES2011) Cambridge. [3] J. -P. Rueff et al., PRL 106 (2011) 186405. [4] K. Miyake, J. Phys.: 

Condens. Matter 19 (2007) 125201. [5] G. Seyfarth et al., arXiv:1111.4873v1.

SE11 

Electrical resistivity measurement under pressure in the heavy fermion 

antiferromagnetic compound Ce2PtGa12 Ryo Sasaki 1 , Kazuyuki Matsubayashi 1 , Takuya Shiraishi 2 , Tetsuro Yamashita 2 , Shigeo 

Ohara 2 and Yoshiya Uwatoko 1 

1 

Institute for Solid State Physics, the University of Tokyo, Kashiwa, Chiba 277-8581, 

Japan 

2 

Department of Engineering Physics, Electronics and Mechanics, Graduate School of 

Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan 

Ce-based heavy-fermion ternary compounds have been of interest because of 

their exotic physical properties under pressure, such as magnetic ordering and 

superconductivity.[1] In these systems, there is a competition between magnetic order 

of f-electrons (RKKY effect) and the screening of magnetic moments (Kondo effect) 

producing large effective electron masses. Ce 2PtGa 12 orders antiferromagnetically at 7 

K, and specific heat measurements suggest that it is a moderate heavy-fermion system 

with γ 191 mJ/mol K 2. For understand of competition between RKKY and Kondo 

effect, We have measured the electrical resistivity under pressure on Ce 2PtGa 12 single 

crystal. In this paper, we will report the suppression of the antiferromagnetic order 

under higher pressure and discuss the electronic state in the vicinity of the critical 

pressure. 

[1] R. T. Macaluso et al., J. Solid State Chem. 178 (2005) 3547. 

SE12 

Anisotropy of URhGe 

Jack M Barraclough 1 *, Edward A Yelland 1 and Andrew D Huxley 2 

1 

School of Physics and Astronomy, University of St Andrews and Scottish Universities 

Physics Alliance (SUPA), United Kingdom 

2 

School of Physics, University of Edinburgh and SUPA, United Kingdom 

The heavy fermion material URhGe has garnered interest in recent years as an 

unconventional superconductor. It shows coexistence of ferromagnetism and p-wave 

superconductivity[1], and superconductivity which is re-entrant in magnetic field[2]. 

We now believe the latter effect to be the result of proximity to a topological change 

in the Fermi-surface[3]. In this poster I report recent resistivity measurements on 

samples of URhGe with well-defined current direction. Most previous works do not 

consider this when reporting resistivity, however we find that some features can vary 

significantly as a function of current direction. We discuss how these findings constrain 

the anisotropy of the Fermi surface, and the possibility of a field dependent and/or 

anisotropic scattering rate. I also present data taken on high quality samples close to the 

quantum critical point. Interestingly, there is no enhancement of the superconducting 

Tc near the QCP compared to that observed with the field applied entirely along the 

crystalline b-axis, where a low temperature tricritical point is present. 

[1] F Hardy and A D Huxley, PRL 94 247006 (2005) [2] F Levy et al, Science 308 1343 (2005) [3] 

E A Yelland et al, Nature Physics 7, 890-894 (2011) 

SE13 

Study of spin wave and spin gap in single crystals of CeRu2Al10 using 

inelastic neutron scattering measurements 

D T Adroja 1 *, E A Goremychkin 1 , A D Hillier 1 , Y Muro 2 , J Kajino 3 and T Takabatake 3 

1 

ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom 

2 

Liberal Arts and Sciences, Toyama Prefectural University, Kurokawa 5180, Imizu 

939-0398, Japan 

3 

Department of Quantum matter, ADSM, and IAMR, Hiroshima University, Higashi- 

Hiroshima, 739-8530, Japan 

We have carried out inelastic neutron scattering (INS) investigations on single crystals 

of CeRu 2Al 10 using the high neutron flux spectrometer MERLIN at ISIS facility. The 

crystals (total mass of 2.4g) were mounted in the b-c scattering plane. We carried out 

measurements using neutron incident energy Ei=20 meV at 4.5 K for b // ki and c // 

ki. We have seen a clear dispersive spin wave type excitations coming out from the 

[1 0 0] and [0 2 0] antiferromagnetic zone centres with a single ion anisotropic gap of 

~4.5 meV. On the other hand along [0 0 L] direction the spin excitations exhibit weak 

dispersion with almost Q-independent gap of 8 meV. The intensity of the peak along 

[0 0 L] is maximum at L = 0 and decreases with increasing L value, like Ce 3+ magnetic 

form factor. These results may suggest that excitations in the ab-plane can be explained 

by the gaped spin wave, but along [0 0 L] is dominated by the hybridization effect. We 

will present a detail analysis of the observed excitations. 

SE14 

SE15 

SE16 


Universal behavior in the nonlinear magnetic response of strongly 

correlated metals 

B S Shivaram 1 , D G Hinks 2 , B Nartowt 3 and Pradeep Kumar 3 

1 Department of Physics, University of Virginia, USA 

2 Materials Science Division, Argonne National Labs, USA 

3 Department of Physics, University of Florida, USA 

A diverse class of strongly correlated electronic materials irrespective of whether 

they order magnetically or not, often exhibit a peak in the temperature dependence 

of the linear magnetic susceptibility, χ 1 . In non-linear susceptibility measurements on 

a number of heavy electron materials including in single crystals of the prototypical 

strongly correlated metal, UPt 3, we find that there exists a peak in the third order 

susceptibility, χ 3 as well. This peak in χ 3 occurs at a temperature T 3, which is roughly 

half the temperature T 1, at which the peak in χ 1 appears. This proportionality between 

T 3 and T 1 also reported previously in other heavy fermion systems implies a universal 

behavior in the nonlinear magnetic response of correlated metals. The observed 

proportionality between T 3 and T 1 can is explained by a model which assumes a singlet 

ground state for the spins present in a crystalline electric field with a concomitant 

doublet excited state, separated from the ground state by an energy Δ. This model also 

yields metamagnetic behavior at a magnetic field corresponding to Δ. 

X-ray absorption studies of the Ce2Rh1-xIrxIn8 intermetallic compounds 

Cris Adriano 1 , Nilmar Silva Camilo 2 , Leandro F Bufaical 3 , Leticie Medonca Ferreira 4 , 

Eduardo N Hering 5 , Pascoal G. Pagliuso 1 and Raimundo Lora-serrano 2 * 

1 

Instituto de Fisica 'Gleb Wataghin' UNICAMP, CP 6165, 13083-970 Campinas, SP, Brazil 

2 

Instituto de Fisica, Universidade Federal de Uberlandia, 38400-902 Uberlandia-MG, Brazil 

3 

Instituto de Fisica, Universidade federal de Goias, Goiania-GO, 74001-970, Brazil 

4 

Instituto de Fisica e Matematica, Universidade Federal de Pelotas (UFPel), CP 354, 96010- 

900 Pelotas, Brazil 

5 

Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de 

Janeiro, RJ, Brazil 

Within the series of heavy fermions Ce 2Rh 1-xIr xIn 8 compounds it has been recently observed the occurrence 

of two low-temperature superconducting (SC) phases as a function of temperature both at ambient pressure 

and under applied pressure for intermediate Ir-content (x~0.25-0.7) with remarkable different behavior of 

both states as a function of pressure and x [1]. The details of the observed results seem to be reminiscent 

of the two SC phases found in the CeRh 1-xIr xIn 5 system, thus related to the higher dimensionality and 

structural disorder for the Ce2-1-8 systems. Here, we report the results of extended x-ray absorption fine 

structure measurements performed on Ce 2Rh 1-xIr xIn 8 (x = 0.0, 0.25, 0.75 and 1.0) at T = 10, 150 and 300 

K at the Rh K-edge and at the Ce and Ir-L 3 absorption edges in order to check the extent of the structural 

disorder at the Rh-Ir atomic sites and their relevance for the SC phases observed in the resistivity and 

specific heat measurements in these compounds. Our results point to the trivalent state of the Ce ions, and 

that there is no evidence of phase separation in the lowest measured temperature. 

[1] E. N. Hering, H. A. Borges et al. Phys. Rev. B 82 184517 (2010) 

Polarized neutron diffraction study on the magnetic ordering in 

UMn2Al20 Przemyslaw Swatek 1 *, Piotr Wisniewski 1 , Arsen Gukasov 2 and Dariusz Kaczorowski 1 

1 

Institute for Low Temperatures and Structure Research, Polish Academy of Sciences, 

Wroclaw, Poland 

2 

Laboratoire Leon Brillouin, CEA-CNRS, CE-Saclay, 91191 Gif sur Yvette, France 

The ternary intermetallic compounds UX 2Al 20 (X = Ti, V, Nb, Ta, and Cr), crystallizing with the cubic 

CeCr 2Al 20-type crystal structure, were characterized in the literature as weak Pauli paramagnets [1-3]. 

In striking contrast, the isostructural phase UMn 2Al 20 was reported to order ferromagnetically due to the 

presence of magnetic moments on the uranium atom sites [4]. In this contribution, we present the results 

of our polarized neutron diffraction study on a high-quality single crystal of UMn 2Al 20, which was also 

carefully characterized by means of X-ray diffraction, microprobe, magnetic, electrical transport and 

heat capacity measurements. The bulk properties were found very similar to those published in Ref. 4. 

In particular, the ferromagnetic transition at TC = 17 K was clearly revealed from the magnetic data, 

while the temperature-dependent specific heat and electrical resistivity were found nearly featureless. The 

magnetization density maps derived from the neutron diffraction data, showed that the ferromagnetism 

in UMn 2Al 20 arises due to the magnetic moments carried on the manganese atoms, while the uranium 

sublattice remains nonmagnetic. This result appears perfectly consistent with the behavior of the UX 2Al 20 (X 

= Ti, V, Nb, Ta, and Cr) compounds, in which the U atoms do not exhibit any magnetic moments. 

[1] S. Niemann and W. Jeitschko, J. Solid State Chem., 114, 337 (1995). [2] K. Okuda et al. J. Phys. Soc. Jpn. 58, 4296 (1989). 

[3] P. Swatek and D. Kaczorowski, J. Solid State Chem., submitted. [4] C. H. Wang et al., Phys. Rev. B 82, 094406 (2010). 


Poster Friday

Poster Friday 

SE17 


Antiferromagnetic ordering in single-crystalline Ce 2IrSi 3 

Maria Szlawska* and Dariusz Kaczorowski 


Wrocław, Poland 

The novel cerium-based ternary silicide Ce 2IrSi 3, crystallizing with fully ordered 

derivative of the hexagonal AlB 2-type unit cell, has recently been characterized as a 

Kondo lattice that orders antiferromagnetically at TN = 1.3 K [1]. An antiferromagnetic 

character of the ordering was inferred merely from the specific heat and electrical 

resistivity data, collected in applied magnetic fields. With the aim at verification of the 

presumed nature of the ground state, we have performed magnetic studies down to 

0.46 K and in external magnetic fields up to 7 T using a SQUID magnetometer. The 

results unambiguously corroborated the antiferromagnetic phase transition at 1.3 K, 

and additionally revealed pronounced magnetic anisotropy in the ordered state. The 

magnetization component measured within the hexagonal ab plane was found much 

larger than that taken along the c axis. This finding indicates that the magnetic moments 

in Ce 2IrSi 3 are confined to the basal plane. In a magnetic field of 0.5 T applied within 

the easy plane, the compound undergoes a metamagnetic-like phase transition. In turn, 

upon applying magnetic field along the hexagonal c axis some complex, yet more 

subtle changes in the magnetic structure seem to occur. 

[1] M. Szlawska and D. Kaczorowski, Phys. Rev. B 84 (2011) 094430 

SE18 

Berezinskii-kosterlitz-thouless transition in heavy fermion superlattices 

Jian-huang She* and Alexander V Balatsky 

T-4, Los Alamos National Lab, USA 

Recently unconventional superconductivity has been observed in epitaxially grown 

heavy fermion superlattices, where Cooper pairs are confined within two-dimensional 

Kondo lattices (Nature Physics 7, 849(2011)). Here we propose to understand these 

experiments within the framework of Berezinskii-Kosterlitz-Thouless Transition. 

The observed behavior of the superconducting transition temperature can be 

understood in terms of phase fluctuations controlled by vortex-antivortex (un)binding. 

Reasonable agreement is found with the experiments. Furthermore, we predict a 

large renormalization of the penetration depth, which can be measured by future 

experiments. Evolution of the gap is explained by invoking effects of the interface. 

SE19 

Basic properties of the intermetallics APd 5Al 2 (An=Ce, Th, U, Np, Pu, 

Am) 

Jean-christophe Griveau*, Krzysztof Gofryk, Eric Colineau, Thomasz Klimczuk and 

Jean Rebizant 

ITU-JRC-EC, Germany 

WITHDRAWN 


SE20 

Study of vibron quasibound state in CeAg1-xCuxAl3, 0

SE23 

Electronic structure studies of UPt 3 using soft x-ray angle-resolved 

photoemission spectroscopy and band calculation 

Hiroshi Yamagami 1 , Ikuto Kawasaki 2 , Shin-ichi Fujimori 2 , Akira Yasui 2 , Tetsuo 

Okane 2 , Yukiharu Takeda 2 , Yuji Saitoh 2 , Yoshinori Haga 3 , Etsuji Yamamoto 3 and 

Yoshichika Onuki 4 

1 Department of Physics, Kyoto Sangyo University, Japan 

2 Condensed Matter Science Division, Japan Atomic Energy Agency, Japan 



Electronic structure and Fermi surface of heavy fermion superconductor UPt3 have 

been studied by de Haas-van Alphen experiments and various theories [1], and it is 

suggested that U5f itinerant band model is more comparable with the experiments. In 

order to observe the valence band structure of UPt3 directly, angle-angle photoemission 

spectroscopy had been done using a discharge lamp [2]. However a 3-dimensional 

band structure of UPt3 has been not understood well. We have carried out soft x-ray 

angle-resolved photoemission spectroscopy experiment with the twin-helical undulator 

beamline BL23SU of SPring-8, and as a result the U5f itinerant bands of UPt3 can be 

detected together with the Pt 5d bands. In the paper we will discuss the band structure 

of UPt3 with a LDA band calculation. 

[1] G. J. McMullan et al., New J. Phys. 10, 053029 (2008). [2] T. Ito et al., Phys. Rev. B 59, 8923 

(1999). 

SF01 

Field-dependent instability of the candidate quantum spin liquid in 

EtMe 3Sb[Pd(dmit) 2] 2 as revealed by NMR. 

Georgios Koutroulakis 1 *, Tong Zhou 2 , Stuart E. Brown 2 , Joe D. Thompson 1 and Reizo 

Kato 3 


2 UCLA, USA 

3 RIKEN, Japan 

SF02 

WITHDRAWN 

Magnetic states in quasi-2-D iridium oxides with large spin-orbit 

coupling 

Masaaki Isobe 1 *, Hirotaka Okabe1 and Jun Akimitsu 2 

1 

Strongly Correlated Materials Group, National Institute for Materials Science 

(NIMS), Japan 

2 

Department of Physics and Mathematics, Aoyama Gakuin University, Japan 

The discovery of the novel Mott insulating state in Sr 2IrO 4 has developed a new research field 

on solid-state physics [1]. The strong spin-orbit coupling with the moderate on-site Coulomb 

interaction in the 5d electron system yields the unconventional Jeff = 1/2 Mott ground 

state. The 'spin-orbit Mott state' is similar to conventional Mott states in 3d or 4d electron 

systems. However, the Jeff = 1/2 state is a considerably complex state hybridizing spin and 

orbital degrees of freedom. Therefore, investigation of this state may give a new insight 

into d-electron physics, and it may lead to possible unusual cooperative phenomena such as 

anisotropic superconductivity. In this presentation, we review electronic and magnetic states 

in the novel K 2NiF 4-type iridate Ba 2IrO 4 [2]. We found that Ba 2IrO 4 is a quasi-2-D (square 

lattice) Heisenberg antiferromagnet (TN ~ 240 K) in which the magnetic moment (~0.34 

mB/Ir-atom) is significantly reduced by the low-dimensional quantum spin fluctuation with 

a large magnetic correlation |J|. Its electronic state undergoes an M-I transition from the Mott 

insulating state to a non-Fermi-liquid state under high pressure (PC ~ 13.8 GPa) [3]. These 

behaviors are very similar to those in low-dimensional cuprates. 

[1] B.J. Kim et al., Phys. Rev. Lett. 101, 076402 (2008); Science 323, 1329 (2009). [2] H. Okabe et 

al., Phys. Rev. B 83, 155118 (2011). [3] H. Okabe et al., Phys. Rev. B 84, 115127 (2011). 

SF03 

SF04 

SF05 


Quantum critical end point in ucoal proved by NMR measurements 

Hisashi Kotegawa 1 , Hiroki Nohara 1 , Hideki Tou 1 , Tatsuma D. Matsuda 2 , Etsuji 

Yamamoto 2 , Yoshinori Haga 2 , Zachary Fisk 3 , Yoshichika Onuki 4 , Valentin Taufour 5 , 

Dai Aoki 5 , Georg Knebel 5 and Jacques Flouquet 5 

1 Kobe University, Japan 

2 JAEA, Japan 



5 CEA-Grenoble, France 

Quantum critical end point (QCEP) emerges in a pressure - temperature - magnetic field phase diagram in 

ferromagnetic (FM) materials with tricriticality.[1-3] In UGe 2,[1,2] a first-order metamagnetic transition, 

which appears above a critical pressure of ~1.5 GPa, possesses a critical end point (CEP) at a finite T_ 

CEP, above which the transition changes to crossover. The T_CEP decreases under pressure, and reaches 

0 K at the QCEP (P_QCEP ~ 3.6 GPa and H_QCEP ~ 18 T). In case of UCoAl, the QCEP is located at 

P_QCEP ~ 1.5 GPa and H_QCEP ~ 7 T.[3] Both systems exhibit the similar wing structures of the firstorder 

plane, but they are quantitatively different. It is an interesting issue what induces such difference 

and what kinds of quantum criticality is involved in the vicinity of QCEP with both instabilities of the 

magnetism and the Fermi surface. In this presentation, we focus on 59Co-NMR measurements for 

UCoAl at ambient pressure [4] and under pressure. A contrasting behavior between the nuclear spin 

relaxation rates 1/T 1 and 1/T 2 demonstrate that strong Ising-type magnetic fluctuation develops at around 

CEP. The drastic pressure evolution of the fluctuations toward the QCEP is also reported. 

[1] V. Taufour et al., Phys. Rev. Lett. 105, 217201 (2010). [2] H. Kotegawa et al., J. Phys. Soc. Jpn. 80, 083703 (2011). 

[3] D. Aoki et al., J. Phys. Soc. Jpn. 80, 094711 (2011). [4] H. Nohara et al., J. Phys. Soc. Jpn. 80, 093707 (2011). 

The metal-insulator transition in ferromagnetic chromium hollandite 

Yutaka Ueda 1 *, Masahiko Isobe 1 , Tooru Yamauchi 1 , Akiko Nakao 2 , Hironori Nakao 2 , 

Yukinori Ohta 3 and Takehisa Konishi 3 


2 Condensed Matter Research Center and Photon Factory, IMSS, KEK, Japan 

3 Chiba University, Japan 

We discovered a metal to insulator transition (MIT), retaining ferromagnetic in the insulator phase, in 

ferromagnetic K 2Cr 8O 16 [1]. The MIT is accompanied by a structural change from a tetragonal to a 

monoclinic structures [2,3]. In the low temperature monoclinic insulator phase, there is no evidence 

of charge separation/order. Instead, the characteristic displacements of the Cr and O sites, resulting in 

Cr-O bond alternations, are observed in the rectangular columns formed by the four chains (the fourchain 

columns). This indicates a lattice-dimerization with the formation of Cr-tetramer in the four-chain 

columns. The observed structural characteristics and electronic structure calcualtions lead us a model 

of MIT caused by the Peierls instability in the quasi-one-dimensional four-chain column [2], namely 

the MIT is a “pure” Peierls transition of spinless fermions (fully spin polarized electrons). On the other 

hand, isostructural RbxCr 8O 16 shows a ferromagnetic transition at Tc= 270 K but does not show any 

distinct MIT. Rb-deficiency could be a reason for the absence of MIT. In a solid solution system, K2yRbyCr 

8O 16, the lattice parameters increase with increase of y. Tc also increases as Rb concentration 

increases. This is consistent with the decrease of Tc with increasing hydrostatic pressure in K 2Cr 8O 16. 

[1] K. Hasegawa et al., Phys. Rev. Lett. 103 (2009) 146403. [2] T. Toriyama et al., Phys. Rev. Lett. 

107 (2011) 266402 [3] A. Nakao et al., J. Phys. Soc. Jpn. to be published. 

Composition and transverse field-tuned quantum criticality in NbFe 2 

Sven Friedemann 1 , Max Hirschberger 1 , Yang Zou 1 , William J Duncan 2 , Andreas Neubauer 3 , 

Thomas Bauer 4 , Louis Pedrero 5 , Manuel Brando 5 , Christian Pfleiderer 3 and F Malte Grosche 1 


2 Department of Physics, Royal Holloway, University of London, United Kingdom 

3 Physik Department E21, TU Munchen, Germany 

4 Max Planck Insitute for Chemical Physics, Dresden, Germany 


The low-temperature band magnet NbFe2 can be tuned by varying composition, magnetic field or pressure, 

providing an attractive candidate system for investigating quantum criticality in a transition metal compound. 

Near the composition-tuned quantum critical point, NbFe2 displays signatures of a logarithmic Fermi liquid 

breakdown: The electronic specific heat diverges logarithmically ΔC~T lnT and the resistivity exhibits 

non-Fermi-liquid forms Δρ~T3/2 at low temperature T [1]. This quantum critical behavior is linked to 

the suppression of an antiferromagnetic phase in slightly Nb-rich samples which is stabilized towards Ferich 

samples. In addition, NbFe2 with slight Fe excess features a ferromagnetic ground state underlying 

the antiferromagnetic phase. We find the ordered moment to point along the crystalline c-direction in 

the ferromagnetic state. Importantly, the transition temperature of this ferromagnetic ground state can be 

suppressed in a magnetic field perpendicular to the direction of the ordered moments, promoting NbFe2 as an 

interesting candidate to study transverse field tuning in an Ising-like metallic system. We report the significant 

suppression of Fermi liquid behavior close to the transverse-field induced quantum phase transition. 

Moreover, we utilize susceptibility measurements to study the nature of this quantum phase transition. 

[1] M. Brando, W. J. Duncan, D. Moroni-Klementowicz, C. Albrecht, D. Gruener, R. Ballou, and F. M. Grosche, Phys. Rev. Lett. 101, 026401 (2008). 


Poster Friday

Poster Friday 

SF06 


Tuning ferromagnetism in Ce 1-xLaxAuGe: A specific heat and magnetic 

susceptibility study 

Buyisiwe M. Sondezi-mhlungu and Andre M. Strydom 


SF07 

WITHDRAWN 

Anomalous hybridization effects in the cubic quadrupole systems 

PrTr 2Al 20 (Tr= Ti, V) 

Akito Sakai*, Eoin O’farrell and Satoru Nakatsuji 

ISSP, University of Tokyo, Japan 

The Kondo effect, the screening process of magnetic dipole moments by conduction(c) electrons, 

is a well-known many-body phenomenon and recognized as a key mechanism which induces a 

lot of interesting phenomena. Interestingly, nonmagnetic version of the Kondo effect, so-called 

quadrupolar Kondo effect, is theoretically predicted for the f 2 Γ 3 crystalline electric field ground 

doublet[1]. In this theory, the ground state is no longer Fermi liquid due to the overscreening of 

the quadrupole moment by c-electrons. However, it is still uncertain what will happen in a real 

system with lattice periodicity. We have revealed that Kondo effect is observed in cubic PrTr 2Al 20 

for the first time in materials which have nonmagnetic Γ 3 ground doublet. Quadrupolar ordering is 

observed at TQ = 2.0 K (Ti) and 0.6 K (V) respectively, and in particular ferroquadrupolar ordering 

in PrTi 2Al 20[2, 3, 5, 6]. Interestingly, anomalous metallic behaviors were observed in PrV 2Al 20 

above TQ, most likely attributed to the quadrupolar Kondo effect. In this presentation, we will 

report the results of low temperature thermal and transport measurements of PrTr 2Al 20 and discuss 

the possibility of the quadrupolar Kondo effect and quantum critical effect of quadrupolar ordering. 

[1] D. L. Cox, Phys. Rev. Lett. 59 (1987) 1240. [2] Akito Sakai and Satoru Nakatsuji, J. Phys. Soc. Jpn. 80 

(2011) 063701. [3] T. J. Sato, S. Ibuka, Y. Nambu, T. Yamazaki, A. Sakai and S. Nakatsuji, arXiv0301828. 

[4] M. Matsunami, M. Taguchi, A. Chainani, R. Eguchi, M.Oura, A. Sakai, S. Nakatsuji and S. Shin, Phys. 

Rev. B 84 (2011) 193101. [5] T U. Ito, W. Higemoto, K. Ninomiya, H. Luetkens, C.Baines, A. Sakai and S. 

Nakatsuji, J. Phys. Soc Jpn. 80 (2011) 113703. [6] M. Koseki et al., J. Phys. Soc. Jpn. 80 (2011) SA049. 

SF08 

Non-fermi-liquid properties of the non-centrosymmetric heavyfermion 

compound CePtSi: a magnetic field study. 

Andre Strydom 


The ternary intermetallic compound CePtSi and its nonmagnetic equivalent LaPtSi 

form in the non-centrosymmetric tetragonal space group I41/md [1]. The structure is 

an ordered variant of the ThSi 2 type which provides dedicated atomic sites for each of 

the rare-earth atom, Pt, and Si. CePtSi is a heavy-fermion compound with a very large 

electronic specific heat coefficient [2] and apparently with no spontaneous magnetic 

ordering. Non-Fermi-liquid (nFL) behaviour found at low temperatures in a Pt-Si 

variational study of CePtSi has been reported [3], as well as aspects of nFL signatures 

at the verge of magnetic ordering in CePtSi doped with Ge [4]. In this work we focus 

on the low-temperature behaviour of magnetic susceptibility, electrical resistivity, and 

specific heat of CePtSi together with comparative properties in LaPtSi. The focus is on 

the influence of applied magnetic fields and the stability of nFL scaling in CePtSi as a 

function of field. 

1. K. Klepp, and E. Parthe, Acta Cryst. B38 (1982) 1105. 2. W. H. Lee, and N. R. Shelton, Phys. Rev. 

B 35 (1987) 5369. 3. T. Goetzfried et al, J. Low Temp. Phys. 127 (2002) 51. 4. F. Steglich et al, J. 

Low Temp. Phys. 95 (1994) 3. 


SF09 

Vibron quasi-bound state in the non-centrosymmetric tetragonal 

heavy-fermion compound CeCuAl 3 

D T Adroja 1 *, A Del Moral 2 , C De La Fuente 2 , A Fraile 1 , E A Goremyhkin 1 , J Taylor 1 , 

A Hillier 1 and F Fernandez-alonso 1 

1 ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX, United Kingdom 

2 Laboratorio de Magnetismo, Depto Fisica Materia Condensada, Universidad de 

Zaragoza & ICMA, Spain 

We have investigated the non-centrosymmetric tetragonal heavy-fermion 

antiferromagnetic compound CeCuAl 3 (TN=2.5 K) using inelastic neutron scattering 

(INS). Our INS results unequivocally reveal the presence of three magnetic excitations 

centred at 1.3, 9.8, and 20.5 meV. These spectral features cannot be explained within 

the framework of crystal-electric-field (CEF) models and recourse to Kramers’ 

theorem for a 4f 1 Ce 3+ ion. To overcome these interpretational difficulties, we have 

extended the vibron model for cubic CeAl 2 of Thalmeier and Fulde to tetragonal pointgroup 

symmetry. This extension provides a satisfactory explanation for the position 

and intensity of the three observed magnetic excitations in CeCuAl3, as well as their 

dependence on momentum transfer and temperature. On the basis of our analysis, we 

attribute the observed series of magnetic excitations to the existence of a vibron quasibound 

state. 

SF10 

Pressure-induced quantum criticality in the heavy-fermion compound 

CeCoGe2.2Si0.8 J. Larrea J. 1 *, K.-a. Lorenzer 2 , M. Muller 1 , S. Paschen 1 , J. Teysser 3 and H. Ronnow 4 

1 

Institute of Solid State Physics, Vienna University of Technology, Wiedner Haupst. 8 - 10, 1040 Vien, Austria 

2 

Institute of Solid State Physics, Vienna University of Technology, Austria 

3 

de Physique de la Matiere Condensee, Universite de Geneve, Quai Ernest-Ansermet 24, 1211 Geneve, 

Switzerland 

4 

Laboratory for Quantum Magnetism, Ecole Polytechnique Federale de Lausanne, 1015 Lausanne, Switzerland 

The pressure-tuned quantum critical point (QCP) of the antiferromagnetic heavy-fermion compound 

CeCoGe 2.1Si 0.9 was claimed to be dominated by different effects on both sides of the QCP: on the magnetic 

side spin fluctuations govern the criticality, while on the non-magnetic side the criticality is dominated by 

disorder that quenches the spin fluctuations [1]. Here we study high-quality CeCoGe 2.2Si 0.8 samples [2], with 

residual resistance ratios four times larger than those of the previously investigated CeCoGe 2.1Si 0.9 samples. 

Interestingly, while DC magnetic susceptibility measurements show that the Neel temperature of TN = 4K 

at zero pressure is only slightly reduced by pressure up to 3.0 kbar, a much stronger decrease is observed for 

the specific heat anomaly. We will present electrical resistivity and specific heat measurements up to 15 kbar 

and down to 0.05 K, and establish the pressure - temperature phase diagram for CeCoGe 2.2Si 0.8. The critical 

behavior shall be compared to the one observed for both CeCoGe 2.1Si 0.9 and the pure reference compound 

CeCoGe 3 [3]. We hope that this investigation will elucidate the role of disorder. Acknowledgement: 'Financial 

support by the European Research Council (ERC Advanced Grant No 227378) is acknowledged.' 

[1] Alzamora M., Fontes M. B., Larrea J., Borges H. A., Baggio-Saitovitch E. M., Medeiros S. N. Phys. Rev. B 76 125106 

(2007). [2] J. Larrea J, J. Teyssier, H. Ronnow, M. Muller, S. Paschen. Submitted to J. Phys: Conf. Ser. [3] G. Knebel, D. 

Aoki, G. Lapertot, B. Salce, J. Flouquet, T. Kawai, H. Murunaka, R. Settai, Y. Onuki . J. Phys. Soc. Jpn. 78, 074714 (2009). 

SF11 

Anomalous thermoelectric effects in the heavy fermion superconductor 

Ce 2PdIn 8 

Marcin Matusiak, Daniel Gnida and Dariusz Kaczorowski* 

Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Poland 

UPGRADED

SF12 

Unusual normal-state magnetotransport in the heavy-fermion 

superconductor Ce 2PdIn 8 

Daniel Gnida*, Marcin Matusiak and Dariusz Kaczorowski 


Poland 

The normal-state behavior in the heavy-fermion superconductor Ce 2PdIn 8 [1,2] has 

been probed by means of Hall coefficient (RH) and transverse magnetoresistivity (MR) 

measurements. Anomalous non-Fermi-liquid-like features, observed below 8 K in 

both RH(T) and MR(T), are related to underlying quantum critical point, previously 

evidenced in the specific heat and the electrical resistivity data [1-5]. Intriguing 

magnetotransport properties observed in this compound exhibit close similarity to those 

reported before for CeCoIn 5 and can be explained in terms of the recently developed 

theory in which anisotropy of the Fermi surface and strong backflow scattering of 

charge carriers on critical AF spin fluctuations are taken into account. What’s more, 

the magnetotransport in Ce 2PdIn 8 is shown to exhibit novel types of scaling that may 

appear universal for similar systems being at the verge of magnetic instability. 

[1] D.Kaczorowski, A.Pikul, D.Gnida, and V.H.Tran, Phys. Rev. Lett. 103 (2009) 027003; ibid 

104 (2010) 059702. [2] D.Kaczorowski, D.Gnida, A.Pikul, and V.H.Tran, Solid State Commun. 

150 (2010) 411. [3] J.K.Dong, H.Zhang, X.Qiu, B.Y.Pan, Y.F.Dai, T.Y.Guan, S.Y.Zhou, D.Gnida, 

D.Kaczorowski, and S.Y.Li, Phys. Rev. X 1 (2011) 011010. [4] Y.Tokiwa, P.Gegenwart, D.Gnida, and 

D.Kaczorowski, Phys. Rev. B 84 (2011) 140507(R). [5] V.H.Tran, D.Kaczorowski, R.T.Khan, and 

E.Bauer, Phys. Rev. B 83 (2011) 064504. 

SF13 

Specific heat and thermal conductivity studies of UCu4+xAl8-x compounds 

Farzana Nasreen 1 , Milton Torikachvili 2 , Karunakar Kothapalli 3 , Yoshimitsu Kohama4, 

Vivien Zapf 5 and Heinrich Nakotte 6 * 

1 

Department of Physics & Astronomy, University of Nevada, Las Vegas, NV 89154, USA 

2 

Department of Physics, San Diego State University, San Diego CA 92182, USA 

3 

Department of Material Science and Engineering, University of Maryland, College Park, MD, 20744, USA 

4 

The Institute for Solid State Physics, The University of Tokyo, Japan 

5 

MPA-National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New 

Mexico 87545, USA 

6 

Department of Physics, New Mexico State University, Las Cruces, NM 88003, USA 

We report the thermal-conductivity and specific-heat measurements for eight UCu 4+xAl 8-x compounds (0 ≤ x 

≤ 2.0) as a function of temperature and magnetic field. Previous studies provided evidence of a transition from 

magnetic to a non-magnetic heavy fermion state at xcr = 1.15. Here we present complementary thermal-property 

studies as a function of temperature (55 mK - 300 K) and applied magnetic field (0 - 15 T). Specific heat data 

of non-magnetic compound at xcr = 1.15 shows logarithmic divergence of low-temperature C/T and this non- 

Fermi liquid (NFL) behavior can be attributed to the proximity of a quantum critical point. Non-magnetic 

compounds with higher Cu content (x > xcr) exhibit unusual temperature scaling in the specific heat possibly due 

to an increase in disorder between Cu and Al. The complete study of magnetic field effect on NFL behavior was 

hampered by high contribution from nuclear Schottky anomaly at low temperatures. The thermal conductivity 

data show stark contrast between the magnetic (x = 0.5) and non-magnetic compound (x = 1.75) - as evidenced 

in Lorentz numbers for example. Our results confirm that a simple free-electron picture is inadequate for the 

description of the low-temperature thermal conductivity properties in non-magnetic UCu 4+xAl 8-x compounds. 

SF14 

Dynamical cluster approximation results of the two-orbital Hubbard 

model 

Hunpyo Lee 1 , Yu-zhong Zhang 2 , Harald Jeschke 1 and Roser Valenti 1 * 

1 Institute for Theoretical Physics, University of Frankfurt, Germany 

2 Physics, Tongji University, China 

The orbital-selective phase transition (OSPT), which is induced by the interplay 

of a narrow band of localized electrons and a wide band of itinerant electrons, has 

been intensively explored in the multi-orbital systems. Using a dynamical cluster 

approximation including the short-range correlation as well as quantum fluctuations, 

we would like to analyze the behaviors of both degenerate two-orbital Hubbard 

model, where both orbitals have equal bandwidths and one orbital is constrained to be 

paramagnetic, while the second one is allowed to have an antiferromagnetic solution 

and two-orbital Hubbard model with different bandwidth at half-filling. The OSPT, 

Fermi-liquid (FL), non-FL, and insulator behaviors are observed in the both cases. 

Finally, we would discuss the implications of the results in the context of the Fe-based 

superconductors. 

Phys. Rev. B 84, 020401(R) (2011). Ann. Phys. 523, No. 8-9, 689 (2011). Phys. Rev. Lett. 104, 

026402 (2010). 

SF15 

SG01 

SG02 


Renormalized parameters and convergence of energy scales on the 

approach to local quantum critical points 

D. J. G. Crow 1 *, Yunori Nishikawa 2 and Alex Hewson 1 

1 Department of Mathematics, Imperial College London, United Kingdom 

2 Graduate School of Science, Osaka City University, Japan 

We consider a two impurity/dot Anderson model, where the impurities, hybridized 

with separate conduction baths, are coupled by antiferromagnetic exchange interaction 

J and a direct interaction U 12. The model has two types of quantum critical points 

associated, respectively, with a transition between Kondo singlet to a local state, and 

a transition to a local charge ordered state. Using exact expressions for the spin and 

charge susceptibilities in terms of renormalized parameters we predict the values of 

the renormalized parameters on the approach to both types of critical point in terms 

of a single energy scale T*, such that at the critical point T*--> 0. From numerical 

renormalization group calculations we give complete phase diagram, and from an 

analysis of the low energy fixed point deduce the renormalized parameters. The results 

confirm the predictions of the renormalized perturbation theory and determine the 

value of T*. The emergence of a single energy scale which goes to zero at a quantum 

critical point may be a general feature which would lead to a natural explanation of E/T 

scaling which has been observed at the quantum critical points of some heavy fermion 

compounds. 

NMR study of magnetic properties of Eu 1-xSrxMnO 3 

Kenji Shimizu 1 , Masanori Yamaguchi 1 , Shujuan Yuan 2 and Shixun Cao 2 

1 Physics, Faculty of Science, University of Toyama, Japan 

2 Physics, Shanghai University, China 

Perovskite-type manganite EuMnO 3 is known to be a compound with narrow eg-band 

width due to small Eu 3+ ionic radius compared to La 3+ . The Eu 1-xSrxMnO 3 shows complex 

magnetic properties, depending on Sr concentration x [1,2]. We have carried out 55Mn 

spin-echo NMR measurements on polycrystalline Eu 1-xSrxMnO 3 (0≤x≤0.5) samples 

at 4.2 or 1.4K, in order to clarify the microscopic local magnetic state of Mn ions and 

the inhomogeneity in the compounds. Typical NMR spectra have been observed in the 

frequency range from 250MHz to 400MHz. For the A-type antiferromagnetic EuMnO 3, 

the resonance frequency is about 260MHz, which is much lower than that observed for 

Mn 3+ in La 1-xSrxMnO 3. For 0.1 ≤ x ≤ 0.4, the resonance lines, corresponding to Mn 4+ and 

Mn 3+ , have been observed around 310MHz and 390MHz, respectively. Furthermore, 

the spectra originated from Mn 2+ have been observed around 590MHz for 0.1≤x≤0.4. 

For Eu 0.5Sr 0.5MnO 3, the NMR spectrum spreads widely with several distinct peaks in the 

frequency range from 250MHz to 410MHz. In Eu 1-xSrxMnO 3, the spin-glass like behavior 

has been observed around x = 0.5[1,3]. The present NMR spectrum for Eu 0.5Sr 0.5MnO 3 

shows that the compound is in the inhomogeneous state due to competition between the 

antiferromagnetic and the ferromagnetic interactions. 

[1] Y. Tomioka et al., Phys. Rev. B 80 (2009) 174414. [2] Y. Tadokoro et al., Solid State Ionics 108 

(1998) 261. [3] A. Sundaresan et al., Phys. Rev. B 55 (1997) 5596. 

NMR study of successive magnetic transitions in A-site ordered 

perovskite LaMn 3Cr 4O 12 

Y. Kawasaki 1 , S. Takase 1 , Y. Kishimoto 1 , T. Ohno 1 , I. Yamada 2 , K Shiro 2 , R. 

Takahashi 2 , K. Ohgushi 3 , N. Nishiyama 4 , T. Inoue 4 and T. Irifune 4 

1 Institute of Technology and Science, The University of Tokushima, Japan 

2 Graduate School of Science and Engineering, Ehime University, Japan 


4 Geodynamics Research Center, Ehime University, Japan 

In a simple ABO3 perovskite, when 75% of the A-site cations are substituted by another 

element, an A-site-ordered perovskite with a chemical formula of A'A 3B 4O 12 can be formed. 

These materials have attracted much attention, because they show a rich variety of physical 

phenomena, such as heavy-fermion behavior in CaCu 3Ru 4O 12 and giant magnetoresistance 

in CaCu 3Mn 4O 12. These features may be related to the A-A and A-B exchange interactions in 

addition to the usual B-B exchange interaction seen in simple perovskite materials. Recently, 

new A-site ordered perovskite, LaMn 3Cr 4O 12, was prepared by using high pressure synthesis. 

The measurements of magnetic susceptibility and specific heat suggest two antiferromagnetic 

transitions at 150 K and 50 K in LaMn 3Cr4O 12. In this conference, we report microscopic 

investigation on the magnetic properties of this material probed by La NMR. The resonance 

line moderately broadens below 150 K and disappears below 50 K. These results are 

consistent with the two antiferromagnetic transitions. The temperature dependence of Knight 

shift indicates that the transition at 150 K is associated with the B-site Cr spin ordering and 

the other at 50 K is due to the A-site Mn spin ordering. 


Poster Friday

Poster Friday 

SG03 


Magnetic properties of single crystalline U 2Fe 3Ge 

Margarida Henriques 1 *, Denis Gorbunov 2 , Ladislav Havela 3 , Alexander Andreev 2 and 

Antonio Goncalves 1 

1 UCQR, Technological and Nuclear Institute, Portugal 

2 Institute of Physics, Academy of Sciences of the Czech Republic, Czech Republic 

3 Department of Condensed Matter Physics, Faculty of Mathematics and Physics, 

Charles University, Czech Republic 

A number of Laves phases exist in intermetallic compounds based on uranium and 

transition metals. The compact structure of such phases, which leads to small U-U 

spacing and high U coordination numbers, gives rise to the 5f band and strong 

hybridization with the non-f states. U 2Fe 3Ge is a new ternary Laves phase [1], 

crystallizing in the Mg 2Cu 3Si-type structure, an ordered variant of the hexagonal 

MgZn 2-type (C14, P6 3/mmc). It exhibits very short U-U distances (below the Hill limit) 

along the c-axis (3.2 Å), still reaching a ferromagnetic order ( T C = 55 K). Surprisingly 

the Fe sub-lattice does not carry any significant ordered moment. A single crystal of 

U 2Fe 3Ge was prepared by the Czochralski method (a = 5.182(2) Å and c = 7.850(1) Å). 

Magnetization isotherms measured along the principal axes indicate that the magnetic 

moments lie in the basal plane of the hexagonal lattice, with the spontaneous magnetic 

moment of 1 μ B/f.u. and no anisotropy within the basal plane. Magnetic moments 

are therefore perpendicular to the nearest U-U link, but the anisotropy values are 

anomalously low comparing e.g. to isostructural UNi 2. 

[1] M.S. Henriques et al., Solid State Commun. 148 (2008) 159. 

SG04 

Magnetic properties of a 5d transition metal oxide AOsO 4 (A = K, Rb, 

Cs) 

Junichi Yamaura, Kenya Ohgushi and Zenji Hiroi 


We investigate the magnetic properties of AOsO 4 (A = K, Rb, Cs) which takes a 5d 1 

electron configuration and would provide us with an interesting playground for spinorbit 

physics. The compound crystallizes in the scheelite structure comprising a 

distorted diamond network of Os atoms. Magnetic susceptibility at high temperatures 

shows Curie-Weiss behavior with Weiss temperatures of -94, -29 and 12 K for the K, 

Rb and Cs compounds, respectively. For the K and Rb compounds, broad humps are 

observed at 55 and 35 K upon cooling and followed by antiferromagnetic transitions 

at 38 and 22 K, respectively. For the Cs compound, in contrast, no antiferromagnetic 

transition is observed down to 2 K, but an anomaly appears at 151 K, below which 

the Weiss temperature is reduced to 3 K. Markedly, the magnetic effective moments 

estimated from the Curie constants are 0.85, 0.84, and 0.86 Bohr magneton for the K, 

Rb, and Cs compounds, which are much smaller than the spin-only value of 1.73 Bohr 

magneton for S = 1/2. Probably a large spin-orbit coupling must be taken into account. 

SG05 

Enhancement of curie temperature due to the coupling between fe 

itinerant electrons and Dy localized electrons in DyFe 2Zn 20 

Yosikazu Isikawa 1 , Toshio Mizushima 1 , Souta Miyamoto 1 , Keigou Kumagai 1 , Mako 

Nakahara 1 , Hiroaki Okuyama 1 , Takashi Tayama 1 , Tomohiko Kuwai 1 and Pascal Lejay 2 

1 Graduate School of Science and Engineering, University of Toyama, Japan 

2 Institute Neel, MCMF, CNRS, France 

The cubic RX2Zn20 has been recently insensitively examined, where R is rare 

earth atom and X is Fe, Co, Ru, etc. The exchange interaction between R-R is weak 

because R atoms are diluted in this compound. In fact, for X = Co and Ru, Tc is less 

than 10 K for any R. In the case of Fe, however, Tc is significantly enhanced, and 

the origin of this high Tc is suspected to be involved the magnetism of Fe atoms. But 

the origin is not clear at present. We examined the magnetic properties and specific 

heat of DyFe2Zn20, and revealed experimentally unusual magnetic anisotropies, i.e., 

large magneto-crystalline anisotropy at 2 K, which nature, however, disappears in the 

temperatures above 30 K below Tc. We analyzed these anomalous properties based on 

the three assumptions: (1) crystalline electric field and exchange interaction between 

R and R, (2) simplified Moriya theory for Fe, and (3) exchange interaction between 

R and Fe. As a result, the enhancement of Tc, the strong magnetic anisotropy at low 

temperatures, the disappearance of the magnetic anisotropy below Tc down to 30 K, 

and no anomaly of magnetic specific heat at Tc, etc. were well reproduced by this 

calculation. 


SG06 

Anomalous increase of TC in UGa 2 under pressure 

Ladislav Havela 1 , A. Kolomiets 2 , J. Prchal 1 and A. V. Andreev 3 



3 Institute of Physics, Academy of Sciences of the Czech Pepublic, Czech Republic 

SG07 

Phase transition between paramagnetic and spin polarized states in 

MnSi 

Sergey Demishev*, Vladimir Glushkov, Inna Lobanova, Vsevolod Ivanov, Nickolay 

Sluchanko and Alexey Semeno 

Low Temperatures and Cryogenic Engineering, General Physics Institute of RAS, 

Russia 

The of high-field region of the magnetic phase diagram of MnSi is probed by magnetization, 

resistivity and magnetoresistance measurements carried out in the temperature range 1.8-300 K 

for magnetic fields up to 8 T [1]. It is shown that the phase boundary between paramagnetic (PM) 

phase and spin-polarized (SP) phase is well-defined, has no positive slope as it was suggested 

previously, and appears to be practically vertical corresponding to transition temperature Tc~30 K. 

We argue that broad maxima of the resistivity and magnetization derivatives, which develops in 

the diapason T >Tc, are not associated with a “diffuse” SP-PM transition and are a consequence 

of the specific form of functional dependences of these quantities in the paramagnetic phase. It 

is found that in the paramagnetic phase of MnSi a universal relation between magnetoresistance 

and magnetization, Δρ/ρ= a0M 2 , holds in a wide range where magnetoresistance vary by 

more than two orders of magnitude. The analysis of the transport and magnetic resonance data 

favors the explanation of magnetic properties of MnSi by Heisenberg-type localized magnetic 

moments rather than by itinerant magnetism approach. A low temperature anomaly at T~15K 

corresponding to magnetoresistance and g factor changes is reported. 

1. S.V.Demishev et al., Phys. Rev.B 85, 045131 (2012) 

SG08 

ESR in mnsi: Heisenberg localized magnetic moments and spin 

polarons 

Sergey Demishev*, Alexey Semeno, Vladimir Glushkov, Nickolay Sluchanko and 

Nickolay Samarin 

Low Temperatures and Cryogenic Engineering, General Physics Institute of RAS, 

Russia 

High frequency (60 GHz) electron spin resonance (ESR) has been studied in 

manganese monosilicide, MnSi, single crystals [1]. The measurements performed 

within the 4.2-300 K temperatures range at the applied magnetic field up to 70 

kOe have demonstrated that the magnetic resonance in MnSi is due to localized 

magnetic moments of the Heisenberg type with the g factor depending only slightly 

on temperature, g ~ 1.9-2. At the same time, it has been found that the ESR linewidth 

is determined by spin fluctuations and can be quantitatively described in the wide 

temperature range (4.2 K < T < 60 K) in the framework of the Moriya theory using 

the SL(T) function. The revealed deviations from the model of weak itinerant electron 

magnetism commonly used for the description of the magnetic properties of MnSi 

indicate a possible spin-polaron nature of the unusual magnetic properties of this 

strongly correlated metal. 

1. S.V.Demishev et al., JETP Letters, 93, 213 (2011) 

UPGRADED

SG09 

Magnetic susceptibility measurements at high pressures down to T=0.5 

K with SQUID magnetometer 

Yoshiaki Sato 1 *, Shun Makiyama 1 , Yasutaka Sakamoto 1 , Tadahiko Hasuo 1 , Yuji 

Inagaki 1 , Tetsuya Fujiwara 2 and Tatsuya Kawae 1 



We develop a 3He-insert attached to MPMS SQUID magnetometer and a pressure 

cell in order to measure magnetic susceptibility and magnetization precisely at high 

pressures down to T=0.5 K[1]. The 3He insert is made by stainless steel pipe with the 

inner diameter of 6.2mm and outer diameter of 6.5 mm. The liquid 3He is condensed 

in the stainless pipe. The vacuum jacket made of a copper pipe with the outer diameter 

of 8.6 mm is soldered to the stainless pipe, which is also used for the heat exchange 

between 3He gas and 4He bath at T=1.7K. The temperature was measured by RuO 2 

thermometer mounted on the 3He container. A main body of piston-cylinder pressure 

cell is made from Be-Cu. The outer diameter of the cell is 6 mm, while the inner 

diameter is 1.8mm which corresponds to the size of the teflon cell. 

[1] Y. Sato, Y. Nakamura, H. Morodomi, T. Hasuo, Y.Inagaki, T. Kawae, H. S. Suzuki and T. Kitai: 

To be appeared in Journal of Physics: <strong>Conference</strong> Series. 

SG10 

Extinction of photo-luminescence of Mn-doped ZnS nanocolloids in 

weak magnetic field 

Hong-van Bui 1 , Van-ben Pham 1 , Nam-nhat Hoang 2 * and Van-chau Dinh 2 

1 

Faculty of Physics, Vietnam National University, University of Natural Sciences, Viet 

Nam 

2 



The extinction of light passing through a nanocolloidal medium containing ferromagnetic oxide 

(such as Fe 3O 4) putting inside a cavity of weak magnetic field has been observed [1-3]. Here for 

the first time we report the extinction of photo-luminescence of Mn-doped ZnS nanocolloid under 

the applied field of 270 Gauss. The Mn-doped ZnS nanopowders have been synthesized by using 

the hydrothermal method from zinc acetate and natri thiosulfat as the precursors (with SPAN-80 

as the surfactant). The particle size was determined to be within 10-20 nm; the lattice constant a 

= 5.41(2) A. The exitation wavelength was 623.8 nm from a He-Ne laser. We have observed a 

systematic reduction of photo-luminescence of a given liquid nanocolloid with time at applied field 

of 270 Gauss, despite of the field direction and field development (upwards or downwards). The 

50% extinction was achieved after 30 min and the saturation extinction after 1 hour. The memory 

effect was shown to preserve for more than 2 hours. We have measured the temperature of the 

sample during the experiment which was kept constant at 70 oC. We believe the PL extinction was 

associated with the magnetic ordering but the ordering inside a liquid medium is a surprise. 

1. John Philip, J. M. Laskar and Baldev Raj. Appl. Phys. Lett. 92, 221911 (2008). 2. Rajesh Patel. Pure Appl. Opt. 11 (2009) 

125004 (5pp). 3. R.V. Mehta, Rajesh Patel, Rucha Desai, R.V. Upadhyay and Kinnari Parekh. Phys. Rev. Lett. 96,127402 (2006). 

SG11 

Electronic structure of A-site ordered perovskite CaCu3Ti4O12 studied 

by angle-resolved photoemission spectroscopy 

H. J. Im 1 *, M. Tsunekawa 2 , T. Sakurada 1 , K. Kawata 1 , T. Watanabe1, K. Takegahara 1 , 

H. Miyazaki 3 and S. Kimura 4 

1 

Department of Advanced Physics, Hirosaki University, Japan 

2 

Faculty of Education, Shiga University, Japan 

3 

Department of Environmental and Materials Engineering, Nagoya Institute of 


4 

UVSOR Facility, Institute for Molecular Science, Japan 

We present angle-resolved photoemission spectroscopy (ARPES) results of A-site 

ordered perovskite CaCu 3Ti 4O 12 (CCTO), which shows extremely high-dielectric 

constant over a wide range of temperature from 100 to 600 K and has an insulator 

phase in contrast to a metal phase from the result of LDA band calculation. We have 

observed the clear band dispersions, located in the higher binding energy than that 

expected in the LDA calculation, and the negligible spectral weight at the Fermi level 

in agreement with the results of electrical resistivity measurements. From the ARPES 

results, we suggest that CCTO is Mott-insulator caused by the strong correlation effects 

of the electrons in Cu 3d - O 2p hybridization bands. 

SG12 

SG13 

SG14 


Evidence of rattling transition in caged compounds LaRu 2Zn 20 and 

LaIr 2Zn 20: La-NMR studies 

Hideki Tou 1 *, Kenji Asaki 1 , Hisahi Kotegawa 1 , Takahiro Onimaru 2 , Keisuke T. 

Matsumoto 2 , Yukihiro F Inoue 2 and Toshiro Takabatake 2 


2 ADSM, Hiroshima University, Japan 

Recently, RT 2Zn 20 (R = Pr, La; T = Ir, Ru) has attracted much attention because of the coexistence of 

superconductivity and a quadrupole ordered state observed in PrIr 2Zn 20[1,2] Superconductivity is also observed 

in LaRu 2Zn 20 (Tc=0.2 K) and LaIr2Zn20 (Tc=0.6 K), but not in PrRu 2Zn 20[1]. PrRu 2Zn 20 and LaRu 2Zn 20 

undergo first-order structural phase transition at Ts=138 and 150 K, respectively, whereas LaIr 2Zn 20 undergoes 

second-order structural phase transition at Ts=200 K. To investigate the structural phase transition in RT 2Zn 20, 

139La(I=7/2) nuclear magnetic resonance (NMR) measurements have been carried out for LaRu 2Zn 20 and 

LaIr 2Zn 20. For both compounds, quite narrow La-NMR line-widths less than 5 kHz without nuclear quadrupole 

splittings above Ts changes their spectral shape with broad tails distributed over the frequency range of 0.8 MHz, 

evidencing the lowering of the symmetry at La site[3]. Around Ts, the nuclear spin-lattice relaxation rate (1/T1) 

show an unusual enhancement associated with the slowing down of the EFG fluctuations[3].To gain further 

insights, we have measured the nuclear spin-spin relaxation rate (1/T2) for both compounds. We have found that 

the temperature dependence of 1/T2 has maximum around Ts associated with the structural phase transition. We 

will discuss low-energy spin dynamics in RT 2Zn 20 from microscopic points of view. 

[1] T. Onimaru, K. T. Matsumoto, Y. F. Inoue, K. Umeo, Y. Saiga, Y. Matsushita, R. Tamura, K. Nishimoto, I. 

Ishii, T. Suzuki, and T. Takabatake: J. Phys. Soc. Jpn. 79 (2010) 033704. [2] T. Onimaru, K. T. Matsumoto, 

Y. F. Inoue, K. Umeo, T. Sakakibara, Y. Karaki, M. Kubota, and T. Takabatake: Phys. Rev. Lett. 106 (2011) 

177001. [3] K. Asaki, H. Kotegawa, H. Tou, T. Onimaru, K. T. Matsumoto, Y. F. Inoue, T. Takabatake 

Unconventional magnetic ordering in spin-orbit mott insulator with 

honeycomb lattice 

Soham Manni 1 *, Yogesh Singh 2 and Phlipp Gegenwart 1 

1 I. Physikalisches Institut, Georg-August-Universitaet Goettingen, Germany 

2 IISER Mohali, India 

Iridates have recently attracted much attention due to a novel $S_{\rm eff}=1/2$ Mott insulating state, 

driven by the interplay of moderate electronic correlations with strong spin-orbit coupling. We have 

synthesized A 2IrO 3 (A=Na,Li) which is a layered system with Ir moments sitting on a Honeycomb lattice. 

Theoretically, this system has been proposed as solid-state realization of the Heisenberg-Kitaev(HK) 

model, treating the superposition of isotropic antiferromagnetic exchange and highly anisotropic Kitaev 

type ferromagnetic nearest neighbor exchange. HK model predicts gapless spin-liquid ground state with 

Majorana fermionic excitations in Kitaev Limit[1]. Na 2IrO 3 shows a Mott insulating state of $S_{\rm 

eff}=1/2$ moments with predominant antiferromagnetic coupling, indicated by a Weiss temperature of 

$\Theta_W=-116$ K[2]. A bulk antiferromagnetic transition occurs at a much reduced temperature of 

$T_N = 15$ K, indicates substantial frustration. Resonant X-ray magnetic scattering for the Na system 

indicates an unconventional most-likely zig-zag magnetic structure[3]. For Mott insulating Li 2IrO 3 we 

observe a similar ordering temperature of 15 K, while the $\Theta_W$ is drastically reduced to $-33K$. 

These observations are compatible with an enhancement of the Kitaev contribution compared to the 

Na-system, suggesting that Li 2IrO 3 is located closer to the Kitaev limit[4]. Work supported by Erasmus 

Mundus EURINDIA project and the AvH foundation. 

[1] J. Chaloupka et al., Phys. Rev. Lett. 105, 027204 (2010). [2] Y. Singh and P. Gegenwart, Phys. Rev. B 82, 064412 (2010). [3] X. 

Liu et al., Y.Singh et al., Phys. Rev. B {\bf 83}, 220403(R) (2011). [4] Y. Singh, S. Manni, P. Gegenwart, arXiv:1106.0429 

YCr 6Ge 6: A kagome metal? 

Yui Ishii 1 *, Yoshihiko Okamoto 1 , Junichi Yamaura 1 , Hisatomo Harima 2 and Zenji 

Hiroi 1 

1 ISSP, Univ. Tokyo, Japan 

2 Dept. of Physics, Kobe Univ., Japan 

Itinerant electrons on a kagome lattice are known to generate a flat band without 

dispersion. It is expected that the flat band causes exotic phenomena induced by the 

kagome geometry such as a flat-band ferromagnetism. However, this has not been 

experimentally observed in real compounds, possibly because the flat band tends to 

be located far from the Fermi level. We have been looking for a candidate compound 

to realize “kagome metal” and recently focused on YCr 6Ge 6. It crystallizes in the 

HfFe 6Ge 6-type structure (space group P6/mmm) where Cr atoms form a kagome lattice. 

Band-structure calculations show that a flat band really exists slightly below EF 

near the Γ point toward the Κ and Μ points. This suggests that hole doping, such as 

the chemical substitution of Ga for Ge, would make the flat band emerge at EF. We 

successfully synthesized single crystals of YCr 6Ge 6 and YCr 6Ge 6-xGax by the flux 

method. A Curie-Weiss like behavior is observed in magnetic susceptibility for both 

compounds. We will show the magnetic and transport properties and try to reveal the 

characteristics of the kagome metal. 


Poster Friday

Poster Friday 

SG15 


Raman scattering spectra of PrRu 2Zn 20 

Norio Ogita 1 *, Takumi Hasegawa 1 , Masayuki Udagawa 1 , Keisuke Matsumoto 2 , 

Takahiro Onimaru 2 and Toshiro Takabatake 2 

1 Graduate School of Arts and Sciences, Hiroshima Univ., Japan 

2 Graduate School of Advanced Sciences of Matter, Hiroshima Univ., Japan 

PrRu 2Zn 20 has the cubic structure with Fd-3m, where Pr-ion is encapsulated in 

the Frank-Kasper cage by 16 Zn atoms. In analogy of the filled skutterudites, this 

compound is expected to be observed an anharmonic Pr vibration and exotic physical 

properties due to orbital degrees of freedom of the local f electrons. shows structural 

transition at Ts=138K and remains a normal state in electronic conductivity down 

to 0.04K. On the other hand, isostructural PrIr 2Zn 20 shows an antiferro-quadrupolar 

ordering(Tq=0.11K) and a superconductivity(Tc=0.05K), without structural change 

above Tq. The difference of the low temperature properties between PrRu 2Zn 20 and 

PrIr 2Zn 20 might be originated from the structural transition, however, the origin of the 

structural transition and also the crystallographic structure below Ts are not clarified. 

Therefore, we have measured Raman scattering spectra of PrRu 2Zn 20. Among the 

Raman active phonons; 3Ag +4 Eg +9 T2g, 2Ag +4 Eg +6 T2g peaks are observed at room 

temperature. With decreasing temperature, 4 peaks are newly observed below Ts in 

T2g spectra. This suggests the structural change around Ts. In comparison with Eg 

spectra, the observation of the similar energy peaks in both spectra suggests the crystal 

structure below Ts seems to be lower than cubic structure. 

SG16 

Superconducting state in KSn 2 with a MgZn 2-type (C14) Laves phase 

structure 

Shota Miyazaki, Kenji Kawashima, Tsukasa Ipponjima, Michinori Fukuma and Jun 

Akimitsu 


We have been searching for a new superconductor including alkali metal elements 

using high pressure / high temperture technique. High-pressure synthesis technique has 

been successfully employed in the search for new materials and new superconductors. 

To use a closed system for high pressure synthesis is effective not only to stabilize a 

composition but also to expand a solid-solution range. We successfully synthesized 

the polycrystalline sample of KSn 2 as a main phase and discovered that KSn 2 was a 

superconductor with T c = 3.2 K. KSn 2 has a hexagonal MgZn 2-type (C14) structure 

(space group P6 3/mmc, No.194) called Laves phase. The magnetization versus 

magnetic field curve shows a typical type-ll superconducting behavior. We determined 

the lower critical field and penetration depth, to be about H c1(0) = 150 Oe and λ GL(0) = 

210 nm, respectively, using the Ginzburg-Landau equations. From the density of state 

calculations, we found that Sn p-orbital mainly contributes near the N(E F) level and 

plays an important role for the superconducting state in KSn 2. 

SG17 

Layered nanosized structures on basis of diluted magnetic 

semiconductors and heusler alloys 

Evgeny Sergeevich Demidov*, Ekaterina Pavlova, Aleksandr Bobrov, Vitaliy 

Podolskii, Valeriy Lesnikov, Sergey Gusev and Anton Tronov 

Solid State Electronics Chair, Nizhny Novgorod State University, Russia 

The laser and RF magnetron synthesis of nanosized layers of the diluted magnetic semiconductors 

(DMS) on the basis of compounds III-V and elementary semiconductors Ge or Si with Mn or 

Fe impurities and Co 2MnSi Heusler alloys (HA) on single crystal substrates GaAs, Si or Al 2O 3 

with ferromagnetism till 500K was earlier demonstrated [1-3]. In this report our new researches 

of properties of DMS Si:Mn and magnetic tunnel junctions (MTJ) with ferromagnetic HA 

plates and dielectric interlayer are presented. The features of FMR of MTJ with ferromagnetic 

exchange interaction, anisotropic negative magnetoresistance, I-V nonlinearity and hysteresis 

of MTJ and single DMS and HA layers at small current density were observed at 77-300К. 

The high-resolution transmission electron microscopy (HRTEM) and selected area electron 

diffraction (SAED), made on JEM-2100F of JEOL, show that the laser synthesis of epitaxial 

layers of DMS Si:15%Mn/GaAs with Curie point 500K, perfect diamond like crystal structure 

and self-organized superlattice is possible. Supported by RFBR (08-02-01222-a, 11-02-00855a), 

the Ministry of Education of Russian Federation (projects 2.1.1/2833 and 2.1.1/12029) and 

the State contract № 02.740.11.0672 of the Federal purpose program 2009-2013 is acknowledged. 

[1] E.S. Demidov, V.V. Podolskii, V.P. Lesnikov et al, JETP, 106, 110 (2008). [2] E.S. Demidov, B.A. Aronzon, S.N. Gusev et 

al, JMMM, 321 (2009) 690. [3] E.S. Demidov, b, V.V. Podolskii, B.A. Aronzon et al, Bull. RAS: Physics, 74 (2010) 1389. 


SG18 

Metal-insulator and spin-state transition in polycrystalline (Pr 1-yREy) 1xCaxCoO 

3 (RE=rare earth elements) in magnetic fields 

Tomoyuki Naito 1 *, Hiroko Sasaki 1 , Motoharu Kato 1 , Satoru Ogawa 1 , Hiroyuki 

Fujishiro 1 , Terukazu Nishizaki 2 and Norio Kobayashi 2 

1 Iwate University, Japan 


We have measured the temperature dependences of the resistivity and the 

magnetic susceptibility in various magnetic fields up to 17 T and 5 T, respectively, 

for polycrystalline (Pr 1-yREy) 1-xCaxCoO 3 (RE=rare earth elements). For 

(Pr 0.8Sm 0.2) 0.7Ca 0.3CoO 3 sample, a metal-insulator transition (MIT) and spin-state 

transition (SST) between the intermediate (IS) and the low spin (LS) states almost 

simultaneously took place around 40 K at 0 T. The MI-SST temperature decreased 

with increasing magnetic field, and the MI-SST was suddenly suppressed above 10 T. 

The MI-SST temperatures were about 38 K at 5 T and 29 K at 9 T. In the samples with 

higher y, in which the MI-SST temperature at 0 T was higher, the reduction of the MI- 

SST temperature became small and the MI-SST survived up to the highest magnetic 

field in this study. The similar behavior was observed in other RE substituted samples. 

The obtained results suggest that the magnetic field stabilizes the IS state, which 

contrasts with the fact that the application of the external pressure induces the LS state. 

We discuss the origin of the magnetic field effect on the MI-SST. 

SG19 

Magnetic field-induced lattice effects in a quasi-2D organic conductor 

close to the Mott metal-insulator transition 

Mariano De Souza 1 *, Andreas Bruel 2 , Christian Strack 2 , Dieter Schweitzer 3 and 

Michael Lang 2 

1 Physics, Universidade Estadual Paulista - Unesp (Sao Paulo State University), Brazil 

2 Physics, Goethe-Universitat Frankfurt, Germany 

3 Physics, Stuttgart Universitat, Germany 

Organic charge-transfer salts of the κ-phase (BEDT-TTF)$_2$X family have been recognized as prototypes for 

studying electronic correlation phenomena [1]. Their ground states can be tuned either by varying the counter 

anion X or by applying external pressure. For the X = Cu[N(CN) 2]Cl salt, for example, the ground state is an 

antiferromagnetic-Mott insulator, whereas for X = Cu[N(CN) 2]Br, it is a superconductor. Fully deuterated single 

crystals of the latter substance are located on the verge of the Mott metal-insulator (MI) transition and, for this 

reason, constitute a material of particular interest for exploring the critical behavior of the π-electron system 

around the Mott transition [2,3]. Here we present ultra-high-resolution dilatometry studies at varying magnetic 

fields on a fully deuterated X = Cu[N(CN) 2]Br salt. Our thermal expansion data reveal two remarkable features: 

(i) the Mott MI transition temperature T$_{MI}$ = (13.6 ± 0.6)K is insensitive to fields up to 10 T, (ii) for 

fields along the interlayer b-axis, a B-induced first-order transition at T$_{SF}$ = (9.5 ± 0.5)K is observed. 

This transition manifests itself in a sharp negative spike in the expansivity, whose position is found to be field 

insensitive. Possible scenarios to describe this field-induced phase transition will be discussed. 

[1] N. Toyota, M. Lang, J. Muller, Low-Dimensional Molecular Metals 2007, Springer, Germany 

[2] M. de Souza, A. Bruehl, Ch. Strack, B. Wolf, D. Schweitzer, M. Lang, Phys. Rev. Lett. 99, 037003 

(2007) [3] L. Bartosch, M. de Souza, M. Lang, Phys. Rev. Lett. 104, 245701 (2010) 

SG20 

Metallic transition of the colossal magnetoresistance material FexMn1 xS (x=0.18) under high pressure 

Yoshimi Mita 1 *, Tomoko Kagayama 2 , G. M. Abramova 3 , G. A. Petrakovskii 3 and V. V. 

Sokolov 4 

1 

Materials Physics, Engineering Science, Osaka University, Japan 

2 

Center of Quantum Science and Technology under Extreme Conditions, Osaka 


3 

L.V.Kirensky Institute of Physics, Russia 

4 

A.V.Nikolaev Institute of Inorganic Chemistry, Russia 

The discovery of the colossal magnetoresistance in FexMn 1-xS solid solutions [1] aroused 

many researcher’s interests in studying the physical properties of this system. We studied 

the pressure induced phase transition of FexMn 1-xS (x=0.18) by infrared (IR) reflection and 

X-ray analysis up to 40 GPa at room temperature. It is shown by X-ray analysis that the 

structure of this sample is NaCl type at ambient pressure and a structural change starts around 

17 GPa and the mixed phase between the NaCl type low pressure phase and the structure 

unknown high pressure phase continues up to around 25 GPa. On the other hand, the IR 

reflectivity increases from 15 GPa and becomes highly remarkable around 20 GPa. The 

spectra do not show any changes from 30 GPa. These results suggest that the phase transition 

of FexMn 1-xS (x=0.18) at room temperature starts around 15 GPa and completes around 30 

GPa and the high pressure phase is not a band overlapping semimetal but a true metallic. 

G.A. Petrakovskii, L.I. Ryabinkina, N.I. Kiselev, D.A. Velikanov, A.F. Bovina, G.M. Abramova, JETP 

Lett. 69 (1999) 949.

SG21 

Optimal design of IPMSM having double barrier for minimizing 

cogging torque and torque ripple 

Hyoung Uk Nam 1 , Hyun Rok Cha 1 , Kwang Heon Kim 2 , Dae Young Lym 1 and Tae 

Won Jeong 1 

1 Automotive R&D, Korea Institute of Industrial Technology, Korea 

2 Department of Electrical Engineering, University of the Chonnam, Korea 

In this paper, a design method for shape optimization of stator and rotor of a double barrier in 

the form of IPMSM for NEV(Neighborhood Electric Vehicle) is proposed. IPMSM has two big 

problems which are high cogging torque and high torque ripple that causes performance degradation 

of the motor and noise, and vibration during the motor rotation. To solve the problem, ways of 

reducing the cogging torque and torque ripple as a method for forming the shape of the motor stator 

and rotor factors were searched. Especially, the factors which greatly affected cogging torque and 

torque ripple were studied and verified their mutual connection. Moreover it was found that the 

most influential factors was the slot open and the slot teeth angle. The results of the experiment 

which reduced cogging torque and torque ripple verified, while the optimization proceeded on the 

basis of the factors that were searched. So the prototype of the optimized IPMSM was designed, its 

performance was evaluated. The optimization was verified by the performance evaluation. 

[1] Y.D. Yao, D.R. Huang, J.C. Wang, S.H. Liou, S.J. Wang, 1997, IEEE Tran. Magn. 33 1997: 4095. [2] N. Bianchi, S. 

Bolognani, 2008, IEEE Trans. Ind. Appl. 38 (5) 2002 : 1259. [3] T. Ishikawa, M. Matsuda, M. Matsunami, 1998, IEEE Trans. 

Magn. 34 (5) 1998 : 3503. [4] Z.Q. Zhu, D. Howe, E. Bolte, B. Ackermann, 1993, IEEE Trans. Magn. 29 1993:124. [5] Hong 

E, Ben-Ahmed AH, Lucidame J. 1997, Switching flux permanent magnet polyphased synchronous machine. In: Proceedings 

of the 7th European conference on power electronics and applications, Trondheim, Norwegen, 1997: p. 903-908. 

SG22 

Implementation of first-principle calculation in combination with a 

dynamical cluster approximation 

Hunpyo Lee 1 , Kateryna Foyevtsova 1 , Johannes Ferber 1 , Markus Aichhorn 2 , Harald 

Jeschke 1 and Roser Valenti 1 * 

1 Institute for Theoretical Physics, University of Frankfurt, Germany 

2 Institute for Theoretical and computational Physics, TU Graz, Austria 

While the combination of the local density approximation (LDA) with dynamical 

mean field theory (DMFT) opened the door to a realistic description of correlated 

compounds, the improvement of the method is ongoing. In this work, we present a 

combination of LDA with the dynamical cluster approximation (LDA+DCA) in the 

framework of the full-potential linear augmented plane-wave method, and compare our 

results to LDA+DMFT calculations as well as experimental observations on SrVO 3. 

We find a qualitative agreement of the momentum resolved spectral function with 

angle-resolved photoemission spectra (ARPES) and former LDA+DMFT results. As 

a correction to LDA+DMFT, we observe more pronounced coherent peaks below the 

Fermi level, as indicated by ARPES experiments. In addition, we resolve the spectral 

functions in the ${\bf K}_{0}=(0,0,0)$ and ${\bf K}_{1}=(\pi,\pi,\pi)$ sectors of 

DCA, where band insulating and metallic phases coexist. Our approach can be applied 

to correlated compounds where not only local quantum fluctuations but also spatial 

fluctuations are important. 

arXiv:1111.0890 

SH01 

Oscillatory transformative domain wall inner structure of depinning 

domain wall around notched ferromagnetic wire 

Dede Djuhana 1 *, Bambang Soegijono 1 , Hong-guang Piao 2 , Suhk Kun Oh 3 , Seong-cho 

Yu 3 and Dong-hyun Kim 3 

1 Physics, Department of Physics, university of Indonesia, Indonesia 

2 Materials Science and Engineering, Department of Materials Science and 

Engineering, Tsinghua University, Beijing, China, China 

3 Physics, Chungbuk National University, Cheongju 361-763, South Korea, Korea 

We have investigated domain wall (DW) depinning behavior around a geometric notch in ferromagnetic 

nanowires by means of micromagnetic simulation [1]. Nanowires with different notch geometries by 

changing a depth (d) and a half-width of the notch (s) have been considered. A domain wall with a transverse 

wall structure is initially prepared to be positioned at the notch. Depinning field pulse of 1 ns duration is 

applied to trigger DW depinning behavior with a systematic variation of depinning field strengths. With 

increase of s, the domain wall depinning field tends to decrease. Change of an aspect ratio is also considered, 

where a relatively insensitive variation of depinning field is observed with respect to the aspect ratio d/ 

s greater than 2. With variation of depinning field strength, we have found that DW internal structure 

changes during the depinning process. At lower depinning field (< 4 mT), DW keeps the initial tranverse 

wall structure during the depinning process, whereas higher depinning field (> 4 mT), DW is depinned 

with a transformation of the inner structure with antivortex soon after DW has escaped from the notch. The 

transformation of the DW inner structure is obviously related to the Walker breakdown phenomenon. 

[1] M. J. Donahue and D. G. Porter, OOMMF User’s Guide, http://math.nist.gov/oommf (2002). 

SH02 

SH03 

SH04 


Unidirectional thermal effects in current-induced domain wall motion 

Jacob Torrejon 1 , Gregory Malinowski 1 , Javier Curiale 1 , Andre Thiaville 1 *, Daniel 

Lacour 2 , Francois Montaigne 2 and Michel Hehn 2 

1 

Laboratoire de Physique des Solides, Universite Paris-Sud, CNRS , 91405 Orsay, 

France., France 

2 

Institut Jean Lamour, Universite Nancy I, 54506 Vandoeuvre-les-Nancy, France., 

France 

We show unidirectional motion of a domain wall (DW) due to thermal effects in 

permalloy nanostrips using magnetic force microscopy on a RF-contacted sample. A 

deterministic thermal driven motion has been found for current excitation in the range 

of few nanoseconds. The cooperation between thermal effect and spin transfer torque 

induces larger and more effective displacements towards the center of nanostrip, the 

hotter part. The thermal effects are generated by Joule heating, and amplified by poor 

heat diffusion through thick SiO 2 (100 nm). An important issue in thermal transport 

is the temperature gradient related to the positions of sinks (thick Au electrodes), 

responsible (partly at least) for the unidirectional DW motion towards hotter part. Such 

behaviour has been recently predicted by magnons spin transfer [1]. On the other hand, 

the propagation of DW could be affected by other thermoelectric effects. However, we 

anticipate the spin currents created by Spin Seebeck effect [2] or anomalous Nernst 

effect [3] to be small compared to the critical current density for DW motion. 

[1] D. Hinzke et al; PRL 107, 027205 (2011). [2] K. Uchida et al; Nature 455, 778 (2008). [3] S. Y. 

Huang et al ; PRL 107, 216604 (2011). 

Effect of the oersted field on current-induced domain wall motion and 

domain wall chirality in multilayer nanostripes 

Stefania Pizzini 1 *, Zahid Ishaque 1 , Jan Vogel 1 , Vojtech Uhlir 1 , Nicolas Rougemaille 1 , 

Olivier Fruchart 1 , Jean-christophe Toussaint 1 , Julio Camarero 2 , Julio C. Cezar 3 and 

Fausto Sirotti 4 

1 

Institut Neel, Centre National de la Recherche Scientifique, Grenoble, France 

2 

Universidad Autonoma de Madrid, Spain 

3 

European Synchrotron Radiation Facility (ESRF), Grenoble, France 

4 

Synchrotron SOLEIL, Gif sur Yvette, France 

Current-induced domain wall motion is more efficient in Permalloy(Py)/Cu/Co trilayer nanostripes than 

in single Py nanostripes. We used time-resolved photoemission electron microscopy combined with x-ray 

magnetic circular dichroism (XMCD-PEEM) to image the magnetic configuration in the Py layer of 

these nanostripes, during the current pulses, with 50ps time resolution. During the current pulses the Py 

magnetization tilts towards the transverse direction. The large tilt angles (up to 70°) can be reproduced by 

micromagnetic simulations only when both the Oersted field and the magnetostatic interactions between Py 

and Co are taken into account. Magnetic Force Microscopy (MFM) measurements were performed on Py/ 

Metal bilayer nanostripes, with different metal thicknesses, varying the transverse field for a given current 

density. We show that the Oersted field stabilizes transverse domain walls with a transverse component parallel 

to the Oersted field, even for widths and thicknesses of the Py layer for which vortex walls are more stable. 

Once the chirality of the wall is compatible with the Oersted field, the domain wall moves with current pulses 

without changing configuration, indicating that the Walker breakdown is suppressed. This phenomenon could 

therefore explain the large domain wall velocities that we have observed in Py/Cu/Co nanostripes. 

Domain-wall motion in permalloy nanowires with magnetic soft spots 

Andreas Vogel 1 *, Sebastian Wintz 2 , Theo Gerhardt 1 , Lars Bocklage 1 , Thomas Strache 2 , 

Mi-young Im 3 , Peter Fischer 3 , Juergen Fassbender 2 , Jeffrey Mccord 4 and Guido Meier 1 

1 Institut fuer Angewandte Physik und Zentrum fuer Mikrostrukturforschung, Universitaet Hamburg, Germany 

2 Institut fuer Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden-Rossendorf, Germany 

3 Center for X-ray Optics, Lawrence Berkeley National Laboratory, USA 

4 Institut fuer Materialwissenschaften, Christian-Albrechts-Universitaet zu Kiel, Germany 

Recent concepts of nonvolatile data-storage devices involve the controlled motion of magnetic domain walls 

(DWs) in nanowires [1]. To realize such a device, a manageable fabrication process of reproducible and reliable 

pinning sites for individual DWs is required. We use irradiation with chromium ions to create local confining 

potentials via an effective reduction of the saturation magnetization in lithographically predefined regions. Fielddriven 

pinning and depinning at the so-called magnetic soft spots is directly observed using x-ray microscopy 

[2]. The shape of the potential is characterized via micromagnetic simulations and electrical measurements of 

the anisotropic magnetoresistance. Moreover, we demonstrate reliable DW depinning by single current pulses 

in a permalloy nanowire containing a square-shaped magnetic soft spot [3]. A DW can be moved back and forth 

between different soft spots along a wire. Lower requirements on the resolution of the lithography equipment 

in comparison to geometric constrictions on the nanoscale, a small distribution of properties due to parallel 

processing of many pinning sites during implantation, and fine tunability of the strength of the pinning potential 

via the chromium ion fluence make the magnetic soft spots a promising candidate for applications. 

[1] D. A. Allwood, Gang Xiong, M. D. Cooke, C. C. Faulkner, D. Atkinson, N. Vernier, R. P. Cowburn, Science 296, 2003 (2002); 

S. S. P. Parkin, U. S. Patent No. US 683 400 5 (2004). [2] A. Vogel, S. Wintz, J. Kimling, M. Bolte, T. Strache, M. Fritzsche, 

M.-Y. Im, P. Fischer, G. Meier, and J. Fassbender, IEEE Trans. Magn. 46, 1708 (2010). [3] A. Vogel, S. Wintz, T. Gerhardt, L. 

Bocklage, T. Strache, M.-Y. Im, P. Fischer, J. Fassbender, J. McCord, and G. Meier, Appl. Phys. Lett. 98, 202501 (2011). 


Poster Friday

Poster Friday 

SH05 


Direct observation of nearly mass-less domain walls in nanostripes 

with perpendicular magnetic anisotropy 

Stefania Pizzini 1 *, Jan Vogel 1 , Marlio Bonfim 2 , Olivier Boulle 3 , Emilie Jue 3 , Nicolas 

Rougemaille 1 , Mihai Miron 3 , Ales Hrabec 1 , Gilles Gaudin 3 , Julio C. Cezar 4 and Fausto 

Sirotti 5 

1 Institut Neel, Centre National de la Recherche Scientifique, Grenoble, France 

2 Departamento de Engenharia Eletrica, Universidade do Parana, Curitiba, Brazil 

3 Spintec, CEA/CNRS/UJF/GINP, INAC, Grenoble, France 

4 European Synchrotron Radiation Facility (ESRF), Grenoble, France 

5 Synchrotron SOLEIL, Gif-sur-Yvette, France 

Important inertial effects have been recently shown for domain walls in permalloy nanostripes. These 

transient effects, giving rise to an effective domain wall (DW) mass, are caused by deformations of 

the DW internal structure when a current pulse is applied. We have used time-resolved photoemission 

electron microscopy combined with x-ray magnetic circular dichroism to study current-induced DW 

motion in Pt/Co/AlOx nanostripes with perpendicular anisotropy and Rashba spin-orbit coupling. We 

show that in these nanostripes the DWs move at constant speed during the current pulse and inertial 

effects are much smaller than in permalloy nanostripes, i.e. the delay of the linear motion with respect 

to the pulse is less than 1 ns and the transient motion is smaller than 30 nm. The transient displacement 

δq depends of the change of generalized DW angle φ : δq = -Δ/α δφ where Δ the domain wall width at 

rest and α the damping parameter. The negligible inertia in our system is accounted for by the narrow 

DW width and the small DW angle due to the presence of a transverse magnetic field of Rashba origin. 

Such small inertial effects could be efficiently exploited in devices based on manipulation of DWs. 

SH06 

Modified phase diagram of domain walls in FeNi/Cu/Co nanostripes 

Nicolas Rougemaille 1 *, Vojtech Uhlir 1 , Olivier Fruchart 1 , Zahid Ishaque 1 , Jan Vogel1, 

Stefania Pizzini 1 , Zoukaa Kassir-bodon 1 , Aurelien Massboeuf 2 , Andrea Locatelli 3 , 

Onur Mentes 3 , Michal Urbanek 4 and Jean-christophe Toussaint 1 

1 

Institut Neel, Centre National de la Recherche Scientifique, Grenoble, France 

2 

Laboratoire d'Etude des Materiaux par Microscopie Avancee, INAC/CEA, Grenoble, 

France 

3 

Sincrotrone ELETTRA, Trieste, Italy 

4 

Institute of Physical Engineering, Brno University of Technology, Brno, Czech 

Republic 

Magnetic domain walls (DWs) confined in nanostructured magnetic materials display a wealth of specific 

static and dynamic physical properties. For magnetic nanostripes with sub-micron widths and in-plane 

magnetization, head-to-head DWs are either of transverse (TW) or vortex (VW) type and are characterized 

by a chirality, asymmetry and/or polarity. Due to their small size and fast dynamics, magnetic domain walls 

are promising candidates in the area of information processing and storage. The dynamic properties of 

these DW under application of current pulses through the spin transfer torque (STT) is one of the exciting 

subjects of spintronics. We used numerical simulations and analytical modelling to predict the phase 

diagram of transverse versus vortex walls in Py/Cu/Co trilayer nanostripes, in which high current-induced 

DW velocities have been observed. The DW is located in the Py layer while the Co layer is initialized as 

single domain. We have found that due to magnetostatic interactions between Py and Co magnetizations, 

the TWs are energetically significantly more favourable in the Py layer of the trilayer nanostripes than in 

single Py nanostripes. We have experimentally verified part of this modified phase diagram with different 

microscopy techniques, including Magnetic Force Microscopy and Photoelectron Emission Microscopy. 

SH07 

Effect of current on a threshold width for a dimensional transition of 

domain wall dynamics in Co/Ni 

Kab-jin Kim 1 *, D. Chiba 1 , K. Kobayashi 1 , S. Fukami 2 , M. Yamanouchi 2 , H. Ohno 2 

and T. Ono 1 

1 Institute for Chemical Research, Kyoto University, Uji, Kyoto, Japan 

2 Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba- 

ku, Sendai 980-8577, Japan 

The effect of current on the dimensional transition of domain wall (DW) motion is 

investigated in Co/Ni nanowires by accompanying magnetoresistance measurement. As 

reducing the nanowire width, we found that the domain wall (DW) motion is changed 

from stripe pattern expansion to purely wall motion, implying that the dimensional 

transition from 2D to 1D. The threshold width for this transition is found to strongly 

depend on the relative direction of magnetic field and current on DW: parallel 

(antiparallel) direction has much smaller (larger) transition width, which is mainly 

because of different forces mechanism by magnetic field and current. The present work 

provides the upper boundary for domain-wall-motion based devices applications. 

(Acknowledgement) This work was partly supported by a Grant-in-Aid for Scientific Research and 

FIRST Program from JSPS. 


SH08 

Simulations of field driven domain wall motion in permalloy nanowires 

with difference dimension 

Chia-chi Chang 1 , Chao-hsien Huang 2 , Tian-chiuan Wu 3 , Jong-ching Wu 2 and Lance 

Horng 2 

1 

Department of Physics, National Changhua University of Education, Taiwan 

2 

Department of Physics, Taiwan SPIN Research Center, National Changhua 

University of Education, Taiwan 

3 

Department of Electronic Engineering, National Formosa University, Taiwan 

In recent years, the domain wall motion in permalloy nanowire has been intensively 

investigated because it could give promise of a new type memory with many 

advantages. In our researches, the domain wall motion in permalloy nanowires driven 

by external magnetic field have been simulated by a commercial software LLG 

simulation. The simulated results presented that the velocity of DW motion increases 

below a critical field value which is called Walker breakdown field; above that field the 

velocity of domain wall obviously decrease. The velocity of the domain wall and the 

critical field is dependent on the dimension of the nanowire. The domain wall velocity 

increases as the wire width increases, and the critical field decreases as wire width 

increases with non-linear relation. 

1. GEOFFREY S. D. BEACH*, CORNELIU NISTOR, CARL KNUTSON, MAXIM TSOI AND 

JAMES L. ERSKINE, nature materials VOL 4 OCTOBER 2005 2. Andrew Kunz, IEEE Trans. 

Mag. VOL. 42, NO. 10, OCTOBER 2006 3. Stuart S. P. Parkin,* Masamitsu Hayashi, Luc Thomas, 

Science 320, 190 2008 

SH09 

Voltage control of magnetisation and magnetic domain configurations 

in magnetostrictive epitaxial Fe 1-xGa x thin films 

Duncan E Parkes 1 , Stuart A Cavill 2 , Aidan T Hindmarch 3 , Peter Wadley 1 , Fintan Mcgee 1 , 

Kevin W Edmonds 1 , Richard P Campion 1 , Andrew W Rushforth 1 * and Bryan L Gallagher 1 

1 School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom 

2 Beamline I06, Diamond Light Source Chilton, Didcot, Oxfordshire OX11 0DE, United Kingdom 

3 Centre for Materials Physics, Durham University, South Road, Durham, DH1 3LE, United Kingdom 

The control of ferromagnetic domains and domain walls by electrical means is a desirable objective for 

applications in many existing and proposed information storage[1,2] and logical processing[3] devices. One 

route to achieve this goal is via hybrid ferromagnet/piezoelectric transducer devices [4-6] in which a voltage 

applied to the transducer induces mechanical strain in the ferromagnet affecting the magnetic anisotropy through 

the inverse magnetostriction effect. We have implemented epitaxially grown thin films of Fe81Ga19 in such a 

device. Through a combination of magnetotransport measurements, magneto-optical Kerr effect (MOKE) and 

high resolution photoemission electron microscopy (PEEM) we demonstrate that our epitaxial films possess an 

exceptionally large magnetostriction (enhanced over that previously observed in bulk samples[7]) and a strong 

cubic magnetocrystalline anisotropy. We exploit these properties to achieve voltage control of the magnetisation 

and magnetic domain walls, including the reconfiguration of ordered domain patterns in structured geometries, 

and non-volatile switching of the magnetisation in the absence of external magnetic fields. Such functionalities 

will be directly applicable to information storage and processing technologies. 

[1] W.J. Gallagher and S.S.P. Parkin, IBM J. Res. & Dev. 1, 5 (2006). [2] S.S.P. Parkin, M. Hayashi, and 

L. Thomas, Science 320, 190 (2008). [3] D.A. Allwood, et al. Science 309, 1688 (2005). [4] Sang-Koog 

Kim et al., J. Mag. Mat. Res. 267, 127 (2003), [5] J-W Lee et al., Appl. Phys. Lett. 82, 2458 (2003). [6] A.W. 

Rushforth et al., Phys. Rev. B. 78, 085314 (2008). [7] A.E. Clark, et al. J. Appl. Phys. 93, 8621 (2003). 

SH10 

Restricted oscillation period effect in the domain wall propagation 

after walker breakdown 

Xiao-ping Ma 1 , Zhe Fan 1 , Je-ho Shim 2 , Sang-hyuk Lee 2 , Djati Handoko 2 , Hong-guang 

Piao 3 * and Dong-hyun Kim 2 

1 Science of College, Huaihai Institute of Technology, China 

2 Department of Physics, Chungbuk National University, Korea 

3 Materials Science and Engineering, Tsinghua University, China 

Understanding and control of dynamic behaviors for magnetic domain wall (DW) in 

ferromagnetic nanowire has become one of important issues in realization of potential 

spintronic applications such as DW logic and memory devices. In this work, we have 

intensively explored antivortex DW dynamic behaviors in ferromagnetic nanowires after 

Walker breakdown by means of the mircomagnetic simulation [1]. The nanowire has 2000nm 

length. The wire width w varied from 25 to 100 nm, and the wire thickness t varied 

from 0.5 to 12 nm. In all simulation, the material parameter of Permalloy is used. The unit 

cell dimension is 2.5×2.5×t nm3 and the Gilbert damping constant α = 0.01.We have found 

that the DW dynamic behavior in the ferromagnetic nanowire significantly depend on the 

wire thickness and width. Interestingly, the oscillation period of the DW propagation is not 

significantly change with variation of the wire thickness is only dependent the wire width. By 

detailed analysis, we propose that there could be a new mechanism to restrict the oscillation 

period of the DW propagation in the ferromagnetic nanowire after the Walker breakdown. 

[1] M. J. Donahue and D. G. Porter, OOMMF User's Guide, from http://math.nist.gov/oommf (2002).

SH11 

Domain wall motion by thermal gradients in Fe/W(110) 

Jonathan Philippe Chico Carpio 1 *, Anders Bergman 1 , Lars Bergqvist 2 and Olle 

Eriksson 1 

1 Physics and Astronomy (Materials Theory Division), Uppsala University, Sweden 

2 Dept. of Materials Science and Engineering, Royal Institute of Techonolgy (KTH), Sweden 

The Spin Seebeck effect recently observed [1] has opened new areas of research in magnetic materials. 

One consequence of the Spin Seebeck effect is the movement of domain walls in magnetic materials [2]. 

In our current research we have studied the behavior of a domain wall in the presence of a thermal gradient 

in a 2D system by using the atomistic spin dynamics approach present in the UppASD code [3, 5]. This is 

based in the Landau-Lifshitz-Gilbert equation, where the atomistic spins are described using a Heisenberg 

Hamiltonian constructed from parameters obtained from first principles calculations. Temperature effects 

are taken into account by Langevin dynamics [3-4]. The system chosen is a monolayer of Fe on W (110) 

which exhibits a large anisotropy while having a soft exchange [5], resulting in domain wall thickness of 

the order of~ 1 - 2 nanometers. By subjecting this material to a thermal gradient we are able to observe 

a temperature dependent movement of the domain wall as well as changes of the spatial magnetization 

profile of the system. We compare this temperature gradient driven motion with the spin transfer torque 

driven domain wall motion observed for the system when subjected to a current. 

[1] K. Uchida, et al. Observation of the spin Seebeck effect. Nature, 455:778, 2008. [2] D. Hinzke, and U. Nowak. Domain Wall 

Motion by the Magnonic Spin Seebeck Effect. Phys. Rev. Letters, 107:027205, 2011. [3] B. Skubic et al.. A method for atomistic 

spin dynamics simulations: implementations and examples. J. Phys.: Condens. Matter, 20:315203, 2008. [4] V. P. Antropov et 

al. Spin dynamics in magnets: Equation of motion and finite temperature effects. Phys. Rev. B, 54:1019, 1996. [5] A. Bergman, 

et al. Magnon softening in a ferromagnetic monolayer: A first-principles spin dynamics study. Phys. Rev. B, 81:144416, 2010. 

SH12 

Transverse domain wall motion in notched ferromagnetic nanowire by 

spin transfer torque 

Arnab Ganguly, Anjan Barman and Saswati Barman* 

Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for 

Basic Sciences, Saltlake, Kolkata, India, India 

We have investigated domain wall motion in notched permalloy nanowires driven by 

spin polarized current. We solve modified Landau-Lifshitz Gilbert equation including 

the effect of spin-transfer torque by micromagnetic simulation. The ferromagnetic 

ground states for the studied geometries show transverse domain walls located at 

different regions depending upon the position, shape, dimension and symmetry of the 

notch in the nanowire. We have studied the effect of the spin torque on domain-wall 

displacement and domain-wall velocity. We find that the domain wall velocity is higher 

for single notched nanowire as compared to multiple notches. For rectangular notches 

of dimension 10 nm x 5 nm, transverse domain wall is pinned at one edge of the notch 

but it gets depinned for current density ~ 10 8 A/m 2 . We observe the current induced 

domain wall oscillation followed by a damped periodic translational motion of the 

transverse wall along with a switching of transverse domain wall from ‘?’ to ‘V’ like 

configuration and vice versa via head to head or tail to tail domain wall formation. 

1. Z. Li and S. Zhang, Phys.Rev. B, 70, 024417 (2004) . 2. A. Thiaville, Y. Nakatani, J. Miltat, and N. 

Vernier, J. Appl. Phys. 95, 7049 (2004) . 3. M. Hayashi, L. Thomas, C. Rettner, R. Moriya, X. Jiang, 

and S. S. P. Parkin, Phys. Rev. Lett. 97, 207205, (2006). 4. P. Chureemart, R. F. L. Evans and R. W. 

Chantrell, , Phys.Rev. B 83, 184416 (2011). 

SH13 

Domain wall configuration and magneto-transport properties in dual 

spin-valve with 

Byong Sun Chun 1 *, Chanyong Hwang 1 , Han-chun Wu 2 , Mohamed Abid 3 , Su Jung 

Noh 4 and Young Keun Kim 4 


2 CRANN, School of Physics, Trinity College Dublin, Ireland 

3 Ecole Polytechnique Federale de Lausanne, Switzerland 


The effect of the direction of the applied magnetic field on the magneto-transport properties 

including domain wall (DW) configuration and magnetization reversal process has been 

studied with a synthetic antiferromagnet-based dual spin-valve (SAF-DSV) structure (i.e. 

the SV structure is doubled symmetrically with respect to the FM). We can tune the DW 

configuration and its reversal process from a vortex to a transverse type by changing the 

direction of applied magnetic field respect to the nano-scale constricted SAF-DSV. When 

the field is applied along the perpendicular direction to the nano-scale constricted SAF-DSV, 

the perpendicular magnetic moments are developed due to the transverse magnetization 

reversal process. This multi step switching process reflects the pinning and depinning of a 

DW at the nano-scale constriction. Our results also show an asymmetric depinning field. 

We demonstrate, if nano-scale constriction is asymmetric along its length, i.e. expansions 

from both sides of the neck into the two nanowires are not identical, and then an asymmetric 

energy barrier to domain wall propagation is formed. This is due to the difference in DW 

width, which leads to an asymmetry in the domain wall depinning forces. 

SH14 

SH15 

SH16 


Dynamics of domain-wall oscillations in magnetic nanorings driven by 

circularly rotating fields 

Youn-seok Choi, Young-sang Yu, Dong-soo Han, Hyunsung Jung, Ki-suk Lee and 

Sang-koog Kim* 




The manipulation of magnetic domain walls in geometrical confinements such as nanostrips and nanorings 

has become essential in information device technologies [1]. In particular, ring structures have attracted much 

attention because domain walls can be easily positioned and manipulated by the application of magnetic fields 

or currents [2-4]. In the present work, we studied possible transverse domain-wall (TW) oscillations with certain 

frequency ranges in magnetic nanorings driven by circularly rotating fields on the nanoring plane. We used 

a permalloy nanoring with an onion state that has a tail-to-tail and a head-to-head transverse wall. From the 

micromagnetic simulations, it was found that the frequency of the TW oscillations varies with the frequency and 

amplitude of the applied rotating field. Moreover, the frequency range of the persistent TW oscillations become 

wider for a stronger field amplitude, as far as the frequency range is below a certain critical frequency value. We 

also found a phase diagram of the characteristic TW oscillation dynamics on the plane of the field strength and 

frequency. We will present our interpretations of those simulation results based on analytical calculations. 

*Corresponding author: sangkoog@snu.ac.kr [1] S. S. P. Parkin et al., Science 320, 190 (2008). [2] J. Rothman et al., 

Phys. Rev. Lett. 86, 1098-1101 (2001). [3] M. Klaui et al., Phys. Rev. B 68, 134426 (2003). [4] Y. Hou et al., Appl. Phys. Lett 

98, 042510 (2011). [5] This work was supported by the Basic Science Research Program through the National Research 

Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant No. 20110000441). 

Modeling field-induced transformations of domain walls in magnetic 

stripes 

Andrzej Janutka 

Institute of Physics, Wroclaw University of Technology, Poland 

WITHDRAWN 

Interaction between propagating spin-waves and domain walls on a 

ferromagnetic nanowire 

June Seo Kim 1 , Martin Staerk 2 , Jungbum Yoon 3 , Chun Yeol You 3 , Luis Lopez-diaz 4 , 

Eduardo Martinez 4 and Mathias Klaeui 1 * 

1 Institut fuer Physik, Johanes Gutenberg-Universitaet Mainz, Germany 

2 Fachbereich Physik, Universitaet Konstanz, Germany 


4 Department of Physics, Universidad de Salamanca, Spain 

The recent discovery that propagating spin waves (SWs) move a domain wall has 

created a new possibility to manipulate magnetization [Dong-Soo, Han et al., Appl. 

Phys. Lett. 94, (2009) 112502]. Here, we numerically investigate the interaction 

between propagating spin waves and a transverse domain wall in a nanowire by 

using micromagnetic simulations. In order to understand the mechanisms that lead to 

domain wall motions, we calculate to domain wall velocity and the depinning fields 

for a pinned domain wall that is depinned in and against the direction of the spin wave 

propagation. We find that the physical origin of the spin wave induced domain wall 

motion strongly depends on the propagating spin wave frequency. At certain spin wave 

frequencies, transverse domain wall oscillations lead to transverse wall displacement 

by the spin waves, while at other frequencies, large reflection and effective momentum 

transfer are the main drivers of the spin wave induced domain wall motion. 


Poster Friday

Poster Friday 

SI01 


Spin oscillations in a free molecular magnet 

Gwang-hee Kim 

Physics, Sejong University, Korea 

Applying an external acoustic wave, we study spin oscillations in a magnetic 

nanoparticle that is free to rotate about its anisotropy axis. Using Hamiltonian of a 

rotated two-state spin system, we have shown that superposition of spin and rotational 

states makes a crucial effect on spin oscillations which exhibit quantum beats of the 

magnetization. In order to study such a beat structure, we compute dynamics of the 

magnetization by employing a perturbative approach, and discuss conditions under 

which this novel quantum effect can be generated. The results are expected to be tested 

in existing experimental techniques. 

SI02 

Effects of nonlinear spin dynamics on spin pumping 

Sankha Subhra Mukherjee, Praveen Deorani, Siddharth Rao, Jae Hyun Kwon and 

Hyunsoo Yang* 

ECE, National University of Singapore, Singapore 

Spin pumping has garnered significant interest in recent times. Most of the studies of 

spin pumping have been on systems in which the magnetization dynamics was linear. 

In nonlinear dynamics, however, large-angle, nonlinear, chaotic dynamics are regularly 

produced. We explore the nature of spin pumping signals resulting from nonlinear 

magnetization dynamical phenomenon. The device geometry comprises of a permalloy 

(Py) layer in contact with a nonmagnetic Pt layer. Magnetization dynamics is produced 

in the system by an rf signal applied to a coplanar waveguide patterned on top. Spin 

injected into the Pt is converted, due to the inverse spin Hall effect (ISHE), to a charge 

current and has been measured across the Pt layer. We will show that the system under 

study shown some high peaks at certain frequencies. The frequencies at which the 

peaks occur have been shown to be non-stochastic, even though one would expect 

them to be stochastic. Also, a frequency shift in the precessional resonant frequency has 

been observed as a function of the applied power. A similar shift had been previously 

observed in spin wave nonlinear dynamics in a different configuration. The origin of 

the peaks and frequency shifts are discussed. 

SI03 

Sharp spectral linewidth in spin torque oscillator with perpendicular 

magnetized Co/Pd free layer 

Yuki Kawada*, Hiroshi Naganuma, Mikihiko Oogane and Yasuo Ando 

Applied Physics, Tohoku university, Japan 

There has been some scientific and practical interest in spin torque oscillator (STO) using 

perpendicular materials [1]. For application of STO to information-communication nano 

RF devices, it is important to investigate linewidth properties, although comprehensive 

understanding of linewidth properties in STO using perpendicular materials is still lacking. 

In this study, we have measured spin torque oscillation in giant magnetoresistance devices 

having a Co/Pd extended free layer and a NiFe/CoFe nanomagnet fixed bilayer. The total 

thickness of Co/Pd is 2.4 nm, and it was confirmed that Co/Pd has perpendicular magnetic 

anisotropy by vibrating sample magnetometer. Spin torque oscillation was measured 

under the low in-plane magnetic field using spectral analyzer. Microwave signal induced 

by spin transfer torque was clearly observed with oscillating frequency at 3.3 GHz. This 

frequency increased with increasing applied current i.e. positive nonlinear frequency shift. 

Obtained minimum spectral linewidth was 13 MHz, which is very small, compared with 

that of previous work on perpendicular materials [2]. Our results suggest that applying the 

low magnetic field to the Co/Pd film plane is efficient to obtain sharp spectral linewidth. 

This work was partly supported by Strategic Japanese-German cooperative program 

(ASPIMATT) from JST and by Japan Society for Promotion of Science. 

[1] S. M. Mohseni et al., Phys. Status Solidi RRL 5, 432 (2011). [2] C. H. Sim et al., J. Appl. Phys. 109, 07C905 (2011). 


SI04 

Clocking schemes for soliton propagation in a ferromagneticallycoupled 

quantum-dot chain 

Kyeong-dong Lee 1 *, Hyon-seok Song 1 , Chun-yeol You 2 and Sung-chul Shin 3 

1 

Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, 

Korea 

2 


3 

Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, 

and Department of Emerging Materials Science, DGIST, Korea 

Transmission of magnetic signals along the ferromagnetically-coupled quantum-dot 

chain is an essential property to realize the magnetic quantum cellular automata. In 

the dot chain, a magnetic signal is represented by a topological soliton with a head-tohead 

or tail-to-tail state. The soliton is exceptionally stable coming from the topology 

of the system potential-energy surface, and could be driven by an external magnetic 

field. In addition to the external field, a global clocking field is used to further control 

propagation speed. We investigate the effect of the clocking field along the hard axis to 

vary the propagation speed, together with the local trigger field along the easy axis to 

initialize the soliton propagation by utilizing micromagnetic simulation. Interestingly, 

it is found that the required static field to initiate the soliton motion is a little larger 

than the minimum field to maintain the soliton motion, and only local trigger field 

is required to initiate the soliton propagation. Furthermore, we reveal the role of the 

global clocking field in the propagation speed, unexpectedly, the clocking field impedes 

the soliton motion. 

SI05 

Spin wave propagation in single crystal Au(001)/Fe(001)/MgO(001) 

waveguides 

Yoichi Shiota, Shinji Miwa, Norikaze Mizuochi, Teruya Shinjo and Yoshishige 

Suzuki* 


The needs for the development of future computing and information storage devices have 

led the emerging field of spintronics. Since spin waves can propagate macroscopic distance 

in ferromagnetic material, they can be used as information carrier. Typically spin wave 

propagations were investigated using garnet films or permalloy films, both of which have small 

crystallographic anisotropy. Here we investigated spin wave propagations using spin wave 

spectroscopy technique [1] in single crystal Fe waveguides with cubic and uniaxial surface 

anisotropies. The sample, Au(001)-50nm/ Fe(001) / MgO(001)-10nm, were fabricated on 

MgO(001) substrate using MBE system. We varied thickness of Fe (0.5-20 nm), waveguide 

width (1-100 µm), and distance of two antennae (0-40 µm). The static in-plane magnetic 

field was applied perpendicular to waveguide. In this way, magneto-static surface waves 

were propagated along the ferromagnetic waveguides. The group velocity of spin wave was 

estimated from the oscillation period in transmission spectra. It was about 8.5 µm/ns in 20 

nm thick waveguide under 500 Oe external magnetic field. We found that this value linearly 

decreases as decreasing the thickness. The contribution of magnetic anisotropies as functions of 

thickness and width of ferromagnetic layer to the spin waves was also investigated. 

[1] V. Vlaminck, et al., Science 322, 410 (2008) 

SI06 

Microscopic theory on the spin relaxation in an inhomogeneous spin 

dynamics 

Nobuyuki Umetsu, Daisuke Miura and Akimasa Sakuma 

Tohoku University, Japan 

The mechanisms of Gilbert damping in materials with inhomogeneous spin dynamics 

are more complicate than that with homogeneous spin dynamics (Kittel mode). It is 

well known that the magnetic impurities contribute to Gilbert damping with Kittel 

mode, on the other hand, the nonmagnetic impurities don’t affect that. Recently, it 

has become clear that in the presence of spin waves (inhomogeneous dynamics), the 

nonmagnetic impurities contribute to Gilbert damping constant, α [1]. In this case, α 

is proportional to square of wave vector q in the limit q→0. The aim of our study is to 

clarify the q-dependence of α in the entire q range from microscopic theory. Our model 

is described by s-d model which consists of localized spins, and conducting electrons. 

In addition to this, we consider the nonmagnetic and magnetic impurities scattering. 

We obtain the precise expression of α from the linear response theory. Consequently, 

we find that α is proportional to 1/q in k↑-k↓

SI07 

Ultrafast transfer of spin in a non-collinearly magnetized multilayer 

Koen Kuiper*, Sjors Schellekens and Bert Koopmans 

Eindhoven University of Technology, Netherlands 

Femtosecond laser pulses can trigger intriguing dynamic phenomena in magnetic 

systems such as quenching of magnetization within 100 fs. An effect hardly explored 

is that due to the laser heating high densities of hot electrons are generated, which 

can lead to transfer of spin angular momentum across different nano-layers at a 

femtosecond timescale. By controlling these spin currents, we effectively combine 

the field of spin-caloritronics with ultrafast magnetization dynamics, providing 

access to spin-caloritronics at ultimate timescales and a unique opportunity for the 

development of new spintronic devices. Malinowski et al. [1] showed in a timeresolved 

MO-Kerr effect experiment that spin-dependent transfer of hot electrons 

can speed up the demagnetization process. Here, in order to maximize the torque 

applied by these electrons, we explore laser induced dynamics in a SiOx/Pt/Co/Al(~1 

nm)/Co/Al sample with a non-collinear orientation of the magnetization, i.e. an inplane 

magnetized top Co- and an out-of-plane bottom Co-layer. We provide a proofof-principle 

demonstration of laser-induced spin transfer across the Al spacer layer. 

The absorbed spin transfer and torque on the magnetization of the receiving layer 

cause an ultrafast canting of its magnetization, which is experimentally observed as a 

successively induced GHz-precession of the in-plane magnetized Co layer. 

[1] G. Malinowski, F. Dalla Longa, J.H.H. Rietjens, P.V. Paluskar, R. Huijink, H.J.M. Swagten, and B. 

Koopmans, Nature Phys. 4, 855-858 (2008). 

SI08 

Investigation of spin wave interference circuit with metallic thin film 

Nana Sato 1 , Koji Sekiguchi 2 * and Yukio Nozaki 3 


2 Department of Physics, Keio University, PRESTO, JST, Japan 

3 Department of Physics, Keio University, CRESTO, JST, Japan 

Spin waves are promising phenomenon for the future spintronic devices with low power 

consumption. For the realization of the spin wave device, we focused on the interference 

effect of spin waves[1]. Magnetostatic surface wave (MSSW) was excited in a NiFe thin 

film by applying a continuous RF field. In order to excite and detect MSSW, a pair of 

asymmetric coplanar wave guides (ACPWs) was fabricated on the NiFe thin film. The 

MSSW was excited by one ACPW, and its signal was detected by the other ACPW as an 

induced voltage in a real-time oscilloscope. The advantage of continuous excitation lies 

in that the MSSW signal becomes stable in time and space, enabling us to sensitively 

detect the spin wave interference. For the observation of spin wave interference, another 

strip line was inserted in the middle position between the ACPWs. From ACPWs in both 

sides of the inserted strip line two different MSSWs having opposite wave vectors were 

excited. By changing the phase of RF fields, the phase difference between two MSSWs 

was controlled. Induced voltage signal at the inserted strip line was changed according 

to the phase difference, indicating that we can observe the interference of MSSWs. 

[1] M. P. Kostylev et al., Appl. Phys. Lett. 87, 153501 (2005) 

SI09 

Current-induced magnetization dynamics of synthetic antiferromagnetic 

free layers 

Seo-won Lee 1 , Daria Gusakova 2 , Liliana Buda-prejbeanu 2 , Ursula Ebels 2 , Bernard 

Dieny 2 and Kyung-jin Lee 1 * 

1 Department of Material Science and Engineering, Korea University, Korea 

2 SPINTEC, UMR CEA/CNRS/UJF & G-INP, INAC, France 

The spin polarized current-induced magnetization dynamics is studied theoretically in the frame of the driftdiffusion 

model [1-3] for two different spin-valve (SV) structures: (i) single free layer (SSV) Pol/Cu/FM and 

(ii) synthetic anti-ferromagnetic free layer (SyAF-SV) Pol/Cu/FM/Ru/FM. In a first step we have analyzed 

the effect of the angular dependence of the spin transfer torque (STT) on the magnetization dynamics for 

SSVs. For this four SSVs were considered: SSV1 (Co(3.5)/Cu(3)/Co(3)), SSV2 (Co(3.5)/Ru(3)/Co(3)), 

SSV3 (Co(3.5)/Cu(3)/Py(3)), and SSV4 (Co(3.5)/Ru(3)/Py(3)). The polarizing layer, Co(3.5), is fixed. We 

found that these four different structures have different magnitudes and angular dependences of STT leading 

to different current - magnetic field phase diagrams with different critical values and ranges for dynamics. 

In the case of SyAF-SVs the drift-diffusion model allows us to take account of not only STT at Cu/FM but 

also STTs at FM/Ru and Ru/FM interfaces. The corresponding phase diagram is distinct from the one where 

STT across Ru has not been considered. Hence, this reveals that the STT through Ru considerably affects 

the dynamics of a synthetic free layer. We discuss the results as a function the strength of the Ruderman- 

Kittel-Kasuya-Yosida (RKKY)-type exchange interactions through Ru. 

[1] A. Brataas, Y. V. Nazarov, and G. E. W. Bauer, Phys. Rev. Lett. 84, 2481 (2000); A. Brataas, Y. V. Nazarov, 

and G. E. W. Bauer, Eur. Phys. J. B 22, 99 (2001). [2] J. Barnas, A. Fert, M. Gmitra, I. Weymann, and V. K. 

Dugaev, Phys. Rev. B 72, 024426 (2005). [3] S. W. Lee and K. J. Lee, J. Kor. Phys. Soc. 55, 1501 (2009). 

SI10 

SI11 


Magnon excitation studies in strongly correlated electron systems 

Cecilia I. Ventura 1 *, Marcello Acquarone 2 and Ivon R. Buitrago 3 

1 Teoria de Solidos, Centro Atomico Bariloche, and Univ. Nac. Rio Negro,, Argentina 

2 IMEM-CNR, Dip. di Fisica, Universita di Parma, Italy 

3 Teoria de Solidos, Centro Atomico Bariloche, and Inst. Balseiro, Argentina 

WITHDRAWN 

Magnetoplasmonic hybrid nanoparticles 

Francesco Pineider 1 *, Giulio Campo 2 , Cesar De Julian Fernandez 1 and Claudio 

Sangregorio 1 

1 Department of Chemistry, University of Florence, CNR-ISTM, Italy 

2 Department of Chemistry, University of Florence, Italy 

Magnetoplasmonics is a very promising branch of active plasmonics that uses a magnetic field 

to modulate plasmon resonance: [1] the field-mediated modulation of the plasmonic response of 

nanoparticles is expected to have strong implications in light guiding applications on plasmon 

resonance-based sensing. [2,3] In this paper we show how ordinary gold nanoparticles' optical 

properties are modified by the magnetic field and describe the origin of such magnetoplasmonic 

behaviour. Then, using a combined approach with the aid of magneto-optics, magnetometry 

and x-ray spectroscopy we investigate several routes to increase the response to the magnetic 

field by adding a magnetic moiety to the gold nanoparticle. We found that when a transition 

metal oxide is added to the gold core in core@shell and heterodimer geometries, the two 

materials (magnetic and plasmonic) behave independently, thus giving rise to bifunctional 

magnetic-plasmonic nanoparticle hybrids. True magnetoplasmonic behaviour is instead 

found when a higher degree of hybridisation exists between the two moieties, as in the case 

when metallic magnetic metals are added to the gold moiety, thus achieving an enhancement 

of the magnetic response of the optical properties and giving rise to a synergic, non-additive 

spectroscopic signature in the magneto-optical spectrum. 

1. V. Temnov et al., Nature Photon., 2010, 4, 107. 2. Anker, J. N. et al. Nature Mater.2008 7, 442. 3. 

Mayer, K. M., Hafner, J. H. Chem. Rev. 2011, 111, 3828. 

SI12 

Inhomogeneous standing spin wave excited by the patterned periodic 

electrode 

Kohei Kiseki 1 , Satoshi Yakata 1 and Takashi Kimura 2 * 

1 Kyushu University, Japan 

2 Kyushu Univsersity, Japan 

There has been a great deal of attention in the spin waves excited in ferromagnetic films 

because of their various potential applications such as spin-wave-based logic circuit 

and the interconnection device between the electric and spintronic devices. Efficient 

excitation and manipulation of the spin wave are important issues for the realizations 

of practical device applications. Spin wave interference in three dimensional spin 

structures may enhance the amplitude of the spin oscillation. For this purpose, we here 

systematically investigated the thickness dependence of resonant frequency of the 

standing spin wave. We prepared Permalloy films with various thicknesses and excite 

the standing spin wave by using a periodic nonmagnetic Cu electrode. The resonant 

frequency of the spin wave was found to increase with the Permalloy thickness. This 

can be understood by the increase of the non-excited layer around the bottom of 

Permalloy layer, which induces the effective magnetic field to the excited layer via 

the exchange interaction. We also perform similar studies of the standing spin wave 

in the other ferromagnetic structures exchange biased and ferromagnetic/nonmagnetic 

multi-layered film and present the optimized structure for increasing the output signal 

induced by the spin wave excitation. 


Poster Friday

Poster Friday 

SI13 


Observation of spin-waves by time-resolved magneto-optic kerr effect 

microscope 

Sang-jun Yun 1 , Jae-chul Lee 2 , Kyung-ho Shin 2 and Sug-bong Choe 1 * 



Spin-wave is an ordering of the magnetization when the magnetization of a 

ferromagnet is tilted away from its equilibrium state. The spin-waves in metallic thin 

films have been recently studied as an emerging field of magnetism for magnetic 

recording and spintronics devices. The spin-waves can be detected by either electrical 

or optical method for either frequency or time domain, respectively. In the frequency 

domain the ferromagnetic resonance has been commonly employed to detect the 

spin-waves, whereas in the time domain, it is typical to detect damped oscillation of 

magnetization excited by a short magnetic pulse via an inductive or optical apparatus. 

Here we report the experimental results on the spin-waves by use of all optical pumpprobe 

method. 20-nm-thick Co thin films are prepared on a GaAs substrate by dc 

magnetron sputtering. The pump beam is focused onto a spot with a diameter 1 μm of 

a sample under an applied magnetic field 2 kOe at normal direction of the film surface. 

The spin-waves are then observed by controlling the tilt angle of the probe beam with 

a fixed pump beam. Using this method, a propagating spin-wave can be measured 

directly and further analysis will be discussed. 

SI14 

Nuclear magnetic resonance study of proton dynamics in ZnO 

Jun Kue Park, Kyu Won Lee and Cheol Eui Lee* 

Department of Physics, Department of Physics and Institute for Nano Science, Korea 

University, Seoul 136-713, Korea, Korea 

Hydrogen acting as a dopant is widely known in compound semiconductors including 

many oxides. However, in order for such doping to be technologically relevant, the 

thermal stability of the H-donor must be enough to avoid degradation during device 

operation at and above room temperature. Here, we have carried out 1H NMR 

measurements in order to understand proton motions in the ZnO lattice at temperatures 

between 200 K and 400 K. In our post-annealed ZnO, there are two proton species, one 

of which can be assigned to protons at interstitial sites (Hi + ) in ZnO. The other species 

shows no appreciable motion in the temperature range. The distinct activation energies 

obtained for the Hi + motion, 0.27 eV and 0.42 eV, are associated with the reorientation 

around the bonding oxygen atom and hopping between neighboring oxygen atoms, 

respectively. These activation energies for diffusion, obtained from the spin-spin 

relaxation measurements, are in close agreement with those obtained from ab initio 

calculations. 

[1] J. K. Park, K. W. Lee, W. Lee, C. E. Lee, D.-J. Kim, and W. Park, Solid State Commun. 152, 116 

(2012). [2] M. G. Wardle, J. P. Goss, and P. R. Briddon, Phys. Rev. Lett. 96, 205504 (2006). [3] L. 

-Q. Wang, X. -D. Zhou, G. J. Exarhos, L. R. Pederson, C. Wang, C. F. Windisch, and C. Yao, Appl. 

Phys. Lett. 91, 173107 (2007). 

SI15 

Micromagnetic study of magnonic band gaps in waveguides with a 

periodic variation of the saturation magnetization 

Florin Ciubotaru*, Andrii V. Chumak, Bjoern Obry, Alexander A. Serga and Burkard 

Hillebrands 

Faculty of Physics, University of Technology, Kaiserslautern, Germany 

Spin wave propagation in micro-sized magnonic crystals (MCs) is intensively studied 

due to their potential technological application for signal processing in spintronic 

devices. Here we report on micromagnetic simulations [1] of the spin wave propagation 

in a MC realized as a permalloy (Ni 80Fe 20) waveguide with a periodical variation of 

its saturation magnetization. In real structures the variation of magnetization can be 

achieved by using an ion implantation technique. The 2 μm-wide waveguide of 40 nm 

thickness is magnetized transversal to its long axis. The MC lattice constant is equal 

to 1 μm. The spin-wave transmission characteristics have been studied as a function 

of the width of the implanted areas and of the level of the magnetization variation M/ 

M0. Frequency band gaps were clearly observed in the spin-wave transmission spectra. 

The dependences of the depth, width and the position in frequency and space of the 

rejection band gaps on the above parameters are referred in our studies. The role of 

the higher order spin-wave width modes on the MC properties is discussed as well. 

Support from DFG (grant SE-1771/1-2) is gratefully acknowledged. 

[1] OOMMF open code, M. J. Donahue, and D. G. Porter, Report NISTIR 6376, NIST, 

Gaithersburg, MD (1999). 


SI16 

Spin-transfer induced spin waves of a magnetic point contact with a 

confined domain wall 

Hiroko Arai, Hiroshi Tsukahara and Hiroshi Imamura* 

Advanced industrial science and technology (AIST), Japan 

Spin-transfer induced microwave oscillation will be a powerful candidate for 

applications in future wireless telecommunication technologies. According to Ref. 

[1], the oscillation of a domain wall between the Bloch- and Neel-type magnetic 

configurations is induced by a direct current and the corresponding oscillation 

frequency is proportional to the current density. It is also known that the current 

injected through a point contact can excite a variety of spin wave modes [2-4]. It is 

intriguing to ask if such spin wave modes can be excited in a thin magnetic layer 

connected to a magnetic point contact containing a domain wall. From our calculation 

we found that three different kinds of spin wave modes can be excited in the thin 

film depending on the bias current density. The low frequency mode just above the 

threshold is the propagating spin wave mode. Then the oscillation frequency increases 

drastically with increasing the current density and reaches more than 100 GHz. At high 

current density the excited spin wave mode is a propagating mode with a large angle 

precession. We also found that applied field independence of the frequency for the 

second mode. We shall discuss the physics behind the excitation of spin wave modes. 

[1] M. Franchin, T. Fischbacher, G. Bordignon, P. de Groot, H. Fangohr, Phys. Rev. B 78, 054447 (2008). 

[2] J. C. Slonczewski, J. Magn. Magn. Mater. 195, L261 (1999). [3] A. Slavin and V. Tiberkevich, Phys. 

Rev. Lett. 95, 237201 (2005). [4] D. V. Berkov and N. L. Gorn, Phys. Rev. B. 80, 064409 (2005). 

SI17 

Spin-torque-nano-oscillator using the perpendicular magnetized 

CoFeB/MgO/CoFeB magnetic tunnel junctions 

Hiroshi Naganuma 1 *, Nobuhito Inami 1 , Yuki Kawada 1 , Mikihiko Oogane 1 , Yasuo 

Ando 1 , Kotaro Mizunuma 2 , Hideo Sato 3 , Michihiko Yamanouchi 3 , Shoji Ikeda 4 and 

Hideo Ohno 4 


2 RIEC, Tohoku University, Japan 

3 CSIS, Tohoku University, Japan 

4 CSIS, RIEC, Tohoku University, Japan 

Perpendicular magnetized free layer in the magnetic tunnel junctions (p-MTJs) has advantages for spintorque-nano-oscillator 

because coherent precession, high output power, and increasing precession frequency 

due to high magnetocrystalline anisotropy, can be expected. In this study, the microwave transmission 

properties were investigated for the p-MTJs using thin CoFeB. The multilayer was prepared by UHV 

sputtering system and patterned it into 40-nm-sized junctions with coplanar waveguide electrode. The 

microwave properties were measured under the in-plane magnetic field of 3 kOe to tilt the free layer. The 

tunnel magnetoresistance ratio was 70% and 0.9% for the out-of-plane and in-plane direction, respectively. 

Below -0.24 mA, the spin torque noise was observed with broad signal. The STO signal was clearly observed 

above -0.30 mA at 6 GHz, and the second harmonic signal was not observed due to the single-precessionmode 

by small junction size. The linewidth and output power was 650 MHz and 1.1 nW, respectively. Power 

has a potential to be more enhanced by stabilizing the pinned layer to increase the relative angle between 

free and pinned layer. This study was partly supported by ASPIMATT (JST), by Grant-in-Aid for Young 

Scientists A (No. 22686001), by FIRST program (JSPS), and by Maekawa-Houonkai foundation. 

SI18 

Planar approximation for spin-transfer devices with tilted polarizer 

Ya. B. Bazaliy* 

Department of Physics and Astronomy, University of South Carolina, Columbia SC, 

USA and Institute of Magnetism of NASU, Ukraine 

Planar spin-transfer devices with dominating easy-plane anisotropy can be described 

by an effective one-dimensional equation for the in-plane azimuthal angle [1-3]. Such 

a description maps the Landau-Lifshitz-Gilbert equation on the Newton equation for 

the motion of classical particle in a one-dimensional potential and thus provides an 

intuitive understanding of the magnetic dynamics, allowing one to obtain qualitative 

results without performing detailed calculations. We apply the effective planar equation 

to describe magnetic switching and precession states in spin transfer devices with tilted 

polarizer [4]. The approach allows one to list the possible dynamic regimes, including 

the precession cycles, and sketch the switching diagram of the device. 

[1] Ya. B. Bazaliy, Appl. Phys. Lett. 91, 262510 (2007). [2] Ya. B. Bazaliy, Phys. Rev. B 76, 

140402(R) (2007). [3] Ya. B. Bazaliy and F. Arammash, Phys. Rev. B 84, 132404 (2011). [4] Ya. B. 

Bazaliy, Phys. Rev. B 85, 014431 (2012).

SJ01 

Fast SpinRAM simulation by GPU 

Kiyoaki Oomaru* and Yoshinobu Nakatani 

The University of Electro-Communications, Japan 

Spin transfer torque driven magnetoresistive random access memory (SpinRAM) is 

one of the candidates of the next generation non volatile memory, and it is studied 

intensively. Micromagnetic simulation is one of the methods to study it. In the 

SpinRAM simulation, because the size of the MTJ element is small, the number 

of the calculation cells is small, and the calculation for one simulation takes only a 

few minutes. However in the real analysis, more than millions of simulations are 

repeated with different conditions, the total simulation time becomes huge. Speed up 

of the simulation is important. Recently, a Graphic Processing Unit (GPU) is used to 

accelerate the micromagnetic simulation. The acceleration rate strongly depends on the 

number of the calculation cells, and a huge number of the calculation cells is required 

to achieve high speed up ratio. Speed up can not be expected in SpinRAM simulation 

by GPU. In this paper, we propose the simulation method to calculate a number of 

the MTJ elements in parallel by GPU, and achieve 75 times of the speed up ratio 

in maximum. This study was supported by New Energy and Industrial Technology 

Development organization (NEDO) partly. 

SJ02 

Micromagnetic simulations for the spin dynamics and Gilbert damping 

constants in nano-dot with perpendicular magnetic anisotropy 

Jungbum Yoon 1 , Chun-yeol You 1 * and Myung-hwa Jung 2 

1 Department of Physics, Inha Universirty, Korea 

2 Department of Physics, Sogang Universirty, Korea 

Spin dynamics and the magnetic damping of a nano-dot ellipse with perpendicular 

magnetic anisotropy (PMA) are presented by the micromagnetic simulations. While the 

in-plane static magnetic field is applied to the long axis of the ellipse, the small in-plane 

RF magnetic field is applied to the short axis of the ellipse to mimic the ferromagnetic 

resonance (FMR) technique. The susceptibility can be obtained by the power spectra 

of fast Fourier transform (FFT) from magnetizations dynamics. There are two regions 

in the external static field dependence resonance frequencies for typical PMA system. 

(I) With small external field, the magnetization is tilted to the static field direction 

with the finite angle from the film normal. (II) If the static field is strong enough, the 

magnetization is aligned to the static field, where the Zeeman energy overcomes the 

PMA energy. In this simulation, the extract Gilbert damping constants from the line 

widths of the resonance peaks from two different regions. Surprisingly enough, the 

obtained values (α_I = 0.0165 and α_II = 0.0194) are different from the input value (α 

= 0.027). It implies that the experimentally obtained α can be different from the real 

values. 

SJ03 

Micromagnetic study on micro-structured ferromagnetic thin film for 

high frequency device applications 

Keigo Ito, Teppei Takashima, Terumitsu Tanaka* and Kimihide Matsuyama 


The ferromagnetic metallic thin films of Fe has been considered as promising materials 

for on-chip microwave devices, owing to the much higher saturation magnetization Ms 

compared with a conventional material of yttrium iron garnet (YIG). Understanding 

of demagnetizing effects, related to Ms, is important for the design of micro-structured 

devices with the high Ms material[1]. In the present study, geometrical effects of microstructured 

magnetic thin films on high frequency magnetic properties are numerically 

investigated with micromagnetic simulations. The standard material parameters of Fe 

with cubic anisotropy are assumed in the simulation. The values of μ’ (@ 1 GHz) and 

the resonance frequency fFMR for various aspect ratios w/t are compared. The increase 

of μ’ with the decrease of w/t is attributable to the size effect in fFMR, related to the 

demagnetizing coefficient along the film normal direction. It should be noticed that 

the μ’ for the same w/t with different w and t is identical. The results suggest that the 

demagnetizing effect on the high frequency magnetic properties becomes prominent 

for the w/t smaller than 400 in the structured Fe thin film. 

[1] N. Cramer et al., J. Appl. Phys., 87, 6911 (2000) 

SJ04 

SJ05 

SJ06 


Atomistic modelling of magnetization dynamics with spin torque 

Phanwadee Chureemart, Richard F. L. Evans, Irene D'amico and Roy W. Chantrell 

Physics, University of York, United Kingdom 

The dynamics of the magnetization following the introduction of a spin current is 

studied by using an atomistic model coupled with spin accumulation. The evolution 

of the magnetization and spin accumulation in a trilayer system are calculated selfconsistently, 

the interaction between magnetisation and spin current provided by an 

s-d exchange term. A spin-polarised current is introduced into the system containing 

a domain wall whose width is varied by changing the anisotropy constant. The 

magnetisation is calculated using an atomistic model based on the Heisenberg 

exchange energy and spin dynamics introduced via the Landau-Lifshitz-Gilbert 

equation. The net spin torque contributes two important components: the adiabatic 

(AST) and nonadiabatic torques (NAST). We show that both arise naturally when 

calculated directly from the spin accumulation. The maximum value of the AST and 

NAST are considered for each thickness of domain wall. Both torques decrease as the 

domain wall thickness increases. The nonadiabaticity factor, defined as the ratio of the 

NAST and AST is also shown. Increasing the domain wall thickness gives rise to a 

small angle between magnetisation in domain wall. Interestingly the degree of NAST 

tends to decay to zero as the thickness of DW increases relative to the spin diffusion 

length. 

Highly parallelized micromagnetic simulator using fast multipole 

method 

Sung-hyun Lee 1 , Chun-yeol You+ and Sung-chul Shin 3 * 

1 Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, Daejeon 305-701, Korea 


3 Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, Daejeon 305-701, Korea, 

Department of Emerging Material Science, DGIST, Daegu 711-873, Korea 

We have developed an alternative method for computing the magnetostatic field of arbitrary-shaped 

ferromagnetic systems instead of fast Fourier transform (FFT). The method is based on the Taylor 

expansion of the potential, as is required by the fast multipole method (FMM)[1][2], the most efficient 

method known for calculating mangnetostatic fields in very large systems. The FMM scales as O(N) in 

both time and space complexity compared to the direct method with O(N 2 ), or FFT with O(N logN)[3] 

and even easier to be parallelized, which is a more valuable solution for larger ferromagnetic systems. 

Graphical processing units (GPU) are now increasingly viewed as data parallel compute coprocessors that 

can provide significant computational performance at low price[4]. We have developed a micromagnetic 

simulator using the parallelized method with GPU and have tested in various configurations. In that case 

speedups of over a factor 100X can easily be obtained compared to the CPU-based OOMMF[5] program 

developed at NIST. The tests are carried out with μMag Standard Problem[6] #1,#2,#3,#4. 

[1] L. Greengard and V. Rokhlin, J. Comp. Phys. 73, 325-348 (1987). [2] P. B. Visscher and D. M. Apalkov, 'Simple 

recursive Cartesian implementation of fast multipole algorithm', [3] R. Ferre, 'Large scale micromagnetic calculations for 

finite and infinite 3D ferromagnetic systems using FFT', Comp. Phys. Commun., 105, 169-186 (1997). [4] CUDA, http:// 

www.nvidia.com [5] OOMMF, http://math.nist.gov/oommf [6] μMag, http://www.ctcms.nist.gov/~rdm/mumag.org.html 

Effect of calculation conditions on the numerical simulation of 

magnetic materials with random magnetic anisotropy 

S. J. Lee 1 , Suguru Sato 1 , Hideto Yanagihara 1 , Eiji Kita 1 * and Chiharu Mitsumata 2 

1 Institute of Applied Physics, University of Tsukuba, Japan 


Numerical simulation was performed on magnetic materials with random anisotropy. 

An assembly of magnetically interacting grains with randomly oriented uniaxial 

anisotropy was provided and magnetization was calculated using the Landau-Lifshitz- 

Gilbert equation. The magnetization in a particular grain is assumed to align in the 

same direction (single spin model).[1] Calculations were carried out for N × N × N 

three dimensional cells changing cell sizes from 5 to 40 nm. The interaction at the 

interface between grains was taken into account by the interaction energy between the 

unit vectors representing grain magnetization directions. N was changed from 10 to 64. 

In the case of N = 10, the relation between coercive forces and grain sizes was obtained 

to be δ = 5.7 in Hc ~ D^δ, and fits to the primitive theory of random anisotropy model 

(RAM) δ = 6. As the N increased, the δ tends to decrease slightly from 5.7 to 4.2. 

The grain sizes where the coercive force becomes less dependent on the grain size, 

suggesting the natural exchange length, did not changed much. 

[1] S.-J. Lee, S. Sato, H. Yanagihara, E. Kita, and C. Mitsumata, J. Magn. Magn. Mater. 323 (2011) 

28. 


Poster Friday

Poster Friday 

SJ07 


Vortex and antivortex formation in magnetic rolled-up nanotubes 

Jehyun Lee 1 , Denys Makarov 2 , Robert Streubel 2 , Carlos Cesar Bof Bufon 2 , Celine 

Vervacke 2 , Dieter Suess 3 , Josef Fidler 3 , Oliver G Schmidt 2 and Sang-koog Kim 1 * 

1 National Creative Research Center for Spin Dynamics & Spin-Wave Devices and Nanospinics 

Lab., Research Institute of Adv. Materials, Dep. of Materials Sci. & Eng., Seoul Nat'l Univ., Korea 

2 Institute for Integrative Nanosciences, IFW Dresden, Germany 

3 Institute of Solid State Physics, Vienna University of Technology, Austria 

Magnetic nanotubes have attracted considerable attention owing to both fundamental and technological 

interest1-2. Using a rolling-up fabrication technology3, patterned multilayer tubes can be prepared that exhibit 

significant modifications of magnetic behaviors compared to those of thin-film structures4-5. In order to elucidate 

the underlying physics, we conducted micromagnetic simulations of possible spin configurations in rolled-up 

nanotubes. When a permalloy platelet of dimensions 400 x 400 x 5 nm3 is rolled up, various spin configurations 

are found to be either C-state, vortex(V) state or anti-vortex(AV) state in the plane of thin films with more spins 

being forced to be aligned along the tube axis. Therefore, the region whose spins are aligned transversely to the 

tube axis is compressed. The modified spin alignment is supposed to increase the anisotropy magnetoresistance 

ratio. Although the reorientation of local magnetizations in the rolled-up tubes results in increases of the exchange 

energy, it reduces much more the magnetostatic energy, particularly for AV state. Consequently, the total energies 

of various spin configurations are similar. The cores in the V and AV states of the rolled-up tubes show another 

interesting feature: the stray fields inside the tubes are cancelled out at the positions. 

This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded 

by the Ministry of Education, Science and Technology (No. 20110000441). 1. S. Allende, J. Escrig, D. Altbir, E. Salcedo, M. Bahiana, 

The Eur. Phy. J. B 66, 37 (2008). 2. E. J. Smith et al., Nano Letters 11, 4037 (2011/10/12, 2010). 3. O. G. Schmidt, K. Eberl, Nature 

410, 168 (2001). 4. C. Muller et al., Appl Phys Lett 100, 022409 (2012). 5. C. Muller et al., Appl Phys Lett 94, 102510 (2009). 

SJ08 

Magneto resistance study using micro magnetic simulations in 

permalloy nano ladder 

Venkateswarlu Dasari*, Vineeth Mohanan Parakkat and Anil P. S. Kumar 


Micromagnetic simulation is one of the tools to investigate magnetization reversal mechanism 

in nano-wires and nano structures. In the open source simulators like OOMMF[1], magneto 

transport studies viz., Anisotropic Magnetoresistance (AMR) is not available and is nontrivial 

since it involves solving the generalized Laplacian equation for getting the spatial 

distribution of current density[2]. In the case of nano wires, the current density is considered 

to be uniform[3]; in this quasi uniform state one can apply phenomenological expression in 

deriving the AMR. We apply this condition in OOMMF-simulations and is compared with 

the commercial software “LLG-simulator”[4]. For this purpose, we considered single wire of 

length(L) 1000nm, width(W) 100nm and thickness(t) 5nm. Both the simulators agree with 

each other within a maximum error of 5%. Further, we studied a ladder structure formed 

by joining these two wires, with interconnects of L=100nm, W=20nm and t=5nm. In this 

ladder structure, we varied number of steps by keeping the periodic separation as 50nm. It 

was found that the coercivity falls non-linearly from 312 to 255G when the number of steps 

increased from 1 to 13. The resistance measured at remanence states drops linearly, which 

indicates the decrease in remanence due to the local nucleation centers. 

1. M. J. Donahue and D.G. Porter, http://math.nist.gov/oommf 2. S. Manikonda, M. Berz and K. Makino, 

IEEE Trans. Comp., 4, 1604 (2005) 3. C. Hassel, F. M. Romer, R. Meckenstock, G. Dumpich, and J. 

Lindner, Phys. Rev. B, 77, 224439 (2008) 4. M. R. Scheinfein, http://llgmicro.home.mindspring.com/ 

SJ09 

Soft layer driven switching of microwave-assisted magnetic recording 

on segmented perpendicular media 

Jing Qiang Goh 1 *, Zhi-min Yuan 2 , Lei Shen 2 , Tiejun Zhou 2 and Yuan Ping Feng 1 

1 Department of Physics, National University of Singapore, Singapore 

2 Data Storage Institute, Agency for Science, Technology and Research, Singapore 

In this work, we use micromagnetic modeling to investigate microwave-assisted 

magnetic recording on segmented perpendicular media. Two types of microwave 

fields, sinusoidal and finite bandwidth square microwaves, have been chosen for 

our study. We show that microwave fields, when applied to the soft segment, can 

assist the magnetization reversal of the hard segment. The calculated assisted 

frequencies are insensitive to the variation of inter-segment exchange coupling of 

segmented perpendicular media. Our results suggest that sinusoidal microwave fields 

are practically more feasible than square microwave fields for the soft layer driven 

switching mechanism of segmented perpendicular media. 

1) C.-K. Goh, Z. min Yuan, T. Zhou, L. Wang, and B. Liu, J. Appl. Phys. 105, 07B908 (2009). 2) C.-K. 

Goh, Z. min Yuan, and B. Liu, Appl. Phys. Lett. 94,152510 (2009). 3) J.-G. Zhu and Y. Wang, IEEE 

Trans. Magn. 47, 4066 (2011). 


SK01 

Top composite free layer non-collinear spin valve for hysteresis-free 

GMR sensors 

Vladimir V. Ustinov*, Michael A. Milyaev, Larisa I. Naumova, Tatiana P. Krinitsina 

and Vladimir V. Proglyado 

Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Russia 

Top spin valves Ta/[FeNi/CoFe]/Cu/CoFe/FeMn/Ta based on FeMn antiferromagnet 

with varying [Fe 20Ni 80/Co 90Fe 10] composite free layer parameters and Cu interlayer 

thickness were prepared by DC magnetron sputtering. GMR characteristics of spin 

valves (SV) were investigated under the conditions of non-collinear SV geometry 

when the applied magnetic field and pinning direction for bottom magnetic layer 

are not collinear. It was shown that the value of low field hysteresis caused by free 

layer magnetization reversal can be reduced down to 0.1 Oe keeping the GMR ratio 

about 10 % by using both layers thicknesses and non-collinearity angle variation. 

The magnetoresistive sensitivity of non-collinear is about 1 %/Oe. Low-hysteresis 

free layer magnetization reversal is mainly due to coherent rotation of magnetization. 

The dependences of low field hysteresis value and GMR ratio on the Cu spacer layer 

thickness and the angle between applied magnetic field and pinning direction are 

presented. 

SK02 

Strong texture and low hysteresis in MnIr-based top spin valve 

Mikhail Milyaev, Larisa Naumova, Vyacheslav Proglyado, Tatiana Krinitsina, 

Nataliya Bannikova and Vladimir Ustinov 

Institute of Metal Physics UB RAS, Russia 

“Spin valve” nanostructures with GMR and TMR are widely used in spintronics. In 

some devices the hysteresis of magnetoresistance must be negligible. The hysteresis is 

weak in the spin valves with axial texture. In this work we study the dependence 

of the free layer hysteresis loop width on the texture strength that is characterized by the 

FWHM of rocking curve. The top spin valves [Ta, (Ni 80Fe 20) 60Cr 40)]/Ni 80Fe 20/Co 90Fe 10/ 

Cu/Co 90Fe 10/Mn 75Ir 25/Ta with various thickness of the magnetic and nonmagnetic layers 

are investigated. On the base of magnetic, magnetoresistance and XRD data the nonlinear 

dependence between FWHM of rocking curves measured at the integrated (111) Bragg 

peak of Ni 80Fe 20, Co 90Fe 10 and Cu layers and free layer coercivity is established. A 

correlation between GMR ratio and FWHM is not revealed. It is shown that in the spin 

valve Ta(50A)/NiFe(30A)/CoFe(20A)/Cu(22A)/CoFe(25A)/MnIr(50A)/Ta(20A) with 

sharp texture, GMR ratio of 10.6 % and minimal coercivity of 8.7 Oe, the free 

layer hysteresis can be effectively reduced down to few tenth of Oersted [1]. This study is 

supported by RFBR, project No. 10-02-00590, by the Program of Presidium RAS, project 

No. 12-P-2-1051, and OFI-UB RAS, project No. 11-2-23-NPO. 

[1] V.V. Ustinov et al. Phys. Met. Metallogr. in press. 

SK03 

Low temperature crystallization process in Co 2FeSi Heusler alloy thin 

films 

Luke Fleet 1 , M. J. Walsh 1 , J. Sagar 1 , T. Nakayama 2 and A. Hirohata 1 * 

1 The University of York, United Kingdom 

2 Nagaoka University of Technology, Japan 

One of the major challenges for Heusler alloys is to achieve a high L 21 ordering at 

low annealing temperatures in order to limit interdiffusion in multilayer devices. 

We report a low temperature crystallization process of polycrystalline Co 2FeSi films 

using in-situ imaging techniques. 20nm thick Co 2FeSi films were annealed in-situ up 

to 600°C with both TEM and diffraction patterns recorded. We show that the grain 

crystallization starts to occur at 230°C with no additional nucleation occurring after 

30 minutes but further annealing does improve the grain ordering. By varying the 

growth conditions it is possible to change the number of nucleation sites and also the 

median grain size. Through varying the initial film morphology it is possible to change 

the number of nucleation sites and also the median grain size from 20 to 250nm. 

Magnetic measurements show that the magnetic moment is over 80% of the theoretical 

value predicted [1]. This shows that a high degree of ordering can be created for 

polycrystalline films after a low temperature anneal of less than 300°C. 

[1] A. Hirohata, and Y. Otani, Epitaxial Ferromagnetic Films And Spintronic Applications 

(Transworld Research Network, 2009).

SK04 

Spin-polarized itinerant electrons in Co2MnAl and Co2MnSi studied 

by magnetic Compton scattering 

Soichiro Mizusaki 1 , Tomohiro Ohnish 1 , Masayoshi Itou 2 , Yoshiharu Sakurai 2 , Tadashi C Ozawa 3 , Hiroaki 

Samata 4 , Yoshihiko Noro 5 and Yujiro Nagata 1 

1 

Aoyama Gakuin University, Japan 

2 

Japan Synchrotron Radiation Research institute (JASRI/SPring-8), Japan 

3 

<strong>International</strong> Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan 

4 Kobe University, Japan 

5 Kawazoe Frontier Technologies, Co. Ltd., Japan 

Investigating the spin-polarized itinerant electron states in the intermetallic alloys and compounds 

is indispensable for the development of potential spintronic materials. In this work, we have studied 

the relationship between the number of sp itinerant electrons and the spin moment in the compounds 

Co 2MnZ (Z=Al or Si), using synchrotron-based Magnetic Compton scattering (MCS)[1], which 

provide the bulk spin-polarized electron momentum distributions, ie. magnetic Compton profiles 

(MCPs). The shape of MCPs depends on the number of spin-polarized electrons of occupied orbitals, 

and the area of MCP corresponds to the spin moment. Co 2MnZ (Z=Al or Si) is a good system to 

investigate the spin-polarized itinerant electron states since the number of sp itinerant electrons can 

be changed without affecting the number of 3d electrons. The following results were obtained . 1. The 

total spin moment increases by 1 μ B/f.u. from Co 2MnAl (4μ B/f.u.) to Co2MnSi (5μ B/f.u.), with one sp 

electron difference. 2: The proportion of the partial spin moment carried by sp itinerant electrons is 

same for Co 2MnAl and Co 2MnSi. From these findings, additional sp electrons occupy the 3d electron 

states and increases the localized spin moment. This enhances the spin polarization of itinerant 

electrons through the indirect magnetic exchange interaction. 

[1] M. J. Cooper, P. E. Mijnarends, N. Shiotani, N. Sakai, and A. Bansil, in X-ray Compton scattering, Oxford 

University Press, Oxford, 2004. 

SK05 

Evidence of inelastic tunneling in magnetic tunnel junctions via 

capacitance-voltage characteristics 

Ajeesh M Sahadevan 1 *, Gopinadhan Kalon 2 , Charanjit S Bhatia 1 and Hyunsoo Yang 2 

1 

Department of Electrical & Computer engineering, National University of 

Singapore, Singapore 

2 

Department of Electrical & Computer engineering, NUSNNI-Nanocore, National 

University of Singapore, Singapore 

Magnetic tunnel junctions (MTJ) have played a key role in the development of HDDs as well as next 

generation non-volatile memories. For high speed applications, capacitance and RC time constant analysis of 

MTJs becomes very important. Also for metal-insulator-metal structures with extremely thin tunnel barriers as 

in MTJs, the capacitance is mainly determined by the interface properties of the structure as the electric field 

penetration becomes significant. Since in MTJs the interfaces are very critical in determining the tunneling 

magnetoresistance (TMR), study of capacitance becomes very relevant for better understanding of these 

devices. We report the temperature dependence of C-V characteristics in MTJs. All our MTJs show a negative 

tunneling magnetocapacitance (TMC) with a magnitude lower than the TMR [1]. At temperatures lower than 

100 K, a zero-bias anomaly appears in the C-V profile. The behavior is similar to inelastic tunneling or zerobias 

anomaly in MTJs. Zero-bias anomaly in the R-V characteristics of MTJs has been attributed to magnon 

and phonon assisted tunneling or thorough impurities inside the barrier. But since the capacitance is mainly 

contributed from the interfaces, the origin of these effects is from the interfaces rather than the bulk. 

[1] P. Padhan et al., Appl. Phys. Lett. 90, 142105 (2007). 

SK06 

Spin-polarization measurements for Co 2MnSi using Co 2MnSi/MgO/ 

NbN epitaxial tunnel junctions 

Ken-ichi Matsuda, Takaho Shinoki, Tomoyuki Taira, Tetsuya Uemura and Masafumi 

Yamamoto 

Div. of Electronics for Informatics, Hokkaido University, Japan 

Spin-polarization measurements were carried out for the Co-based Heusler alloy, Co 2MnSi (CMS, 

for short), using CMS/MgO/NbN epitaxial tunnel junctions. The layer structure was as follows: 

(from the substrate side) MgO buffer (10 nm) /NbN (10 nm)/MgO barrier (1.4-3.2 nm)/CMS (3 

nm)/Co 50Fe 50 (1nm)/IrMn (10nm)/Ru cap (5 nm). All the samples were successively deposited 

on MgO(001) single-crystal substrates in an ultrahigh vacuum chamber. Spin-polarization 

measurements were carried out at 1.5 K using the conventional lock-in technique. The spin 

polarizations (P) were evaluated for three different film compositions of CMS: Co 2Mn 0.72Si 0.81, 

Co 2Mn 1.00Si 0.81, and Co 2Mn 1.40Si 0.81. At H = 0 T, typical differential conductance curves were clearly 

observed, and were well-fitted by the modified-BTK theory [1]. The superconducting energy gap 

extracted from the analysis was about 2.5 meV [2]. The P values evaluated at H = 8 T were 0.41, 

0.50, and 0.54 for respective CMS films. Thus, the P increased with increasing Mn-composition in 

CMS films. This result is consistent with the increase of the TMR ratios for CMS/MgO/CMS fullyepitaxial 

magnetic tunnel junctions, and can be qualitatively understood from the view point of the 

suppression of minority-spin in-gap states that resulted from the reduction of CoMn anti-sites [3]. 

[1] G. J. Strijkers, Y. Ji, F. Y. Yang, C. L. Chien, and J. M. Byers, Phys. Rev. B, 63 (2001) 104510. [2] H. 

Yang, S.-H. Yang, C. Kaiser, and S. Parkin, Appl. Phys. Lett., 88 (2006) 182501. [3] M. Yamamoto, T. 

Ishikawa, T. Taira, G.-f. Li, K.-i. Matsuda, and T. Uemura, J. Phys.: Cond. Matt., 22 (2010) 164212. 

SK07 

SK08 

SK09 


Variation of point-contact andreev reflection spectra of 

ferromagnetically ordered metals 

Elina Tuuli* and Kurt Gloos 

Department of Physics and Astronomy, University of Turku, Finland 

Point-contact Andreev reflection (AR) spectra of ferromagnets are usually fitted with 

modified BTK models that take into account the spin polarization. On the other hand, 

AR spectra of non-magnetic metals are often described by a BTK model that includes 

Dynes' lifetime parameter. The two models yield rather similar spectra and can in fact 

be used to fit the spectra of both magnets and non-magnets. The differences between 

them are most pronounced at low temperatures but strongly suppressed by thermal 

smearing. We have applied the two models to point contacts between the classical 

band ferromagnets Co, Fe, and Ni and the conventional superconductors Nb, Ta, and 

Al as function of temperature. The spectra varied between an absent superconducting 

signal and an occasional Josephson-like anomaly with a large resistance drop at 

zero bias, while many spectra had the typical Andreev reflection double-minimum 

structure. However, we could reproduce the expected constant polarization of the 

ferromagnet and a BCS-type dependence of the superconducting gap only in a few 

cases. This unexpected variation could be related to the interplay of ferromagnetism 

and superconductivity at the interfaces. 

Fabrication of Highly Sensitive Magnetic Tunnel Junctions for Biomagnetic 

Field Sensor Application 

Kosuke Fujiwara 1 *, Mikihiko Oogane 1 , Takuo Nishikawa 2 , Saeko Yokota 1 , Hiroshi 

Naganuma 1 and Yasuo Ando 1 

1 Department of Applyed Physics, Tohoku University, Japan 

2 LC Business Department, Konicaminolta Opto,Inc., Japan 

The discovery of large tunnel magneto-resistance (TMR) effect of over 200% in MgO based 

magnetic tunnel junctions (MTJs)[1,2] enabled us to design highly sensitive magnetic field 

sensors[3,4], such as a bio-magnetic field sensor. For this purpose, we need MTJs with a high 

sensitivity and hysteresis-free responses. In this study, we fabricated MTJs with a NiFe 70/ 

Ru 0.9/ CoFeB 3 (in nm) bottom synthetic ferri-coupled free layer and an MgO barrier layer. 

This thick NiFe layer serves low magnetic anisotropy[5]. The MTJs were annealed at 325°C 

by applying a magnetic field. After the first annealing, we rotated direction of the magnetic 

field to 90 degree and annealed at 300°C. This second annealing redirects easy axis of pinned 

layer. The TMR properties were measured using DC four probes with an applied magnetic 

field along the hard axis of the free layer, and we have successfully observed the very high 

sensitivity of 25.3%/Oe and hysteresis free response. Developed MTJs are promising for 

bio-magnetic sensor application. This work was partly supported by S-Innovation program, 

Japan Science and Technology Agency (JST). 

[1] S. Yuasa et al, Nat. Mater., 3 (2004) 868. [2] S. S. P. Parkin et al, Nat. Mater., 3 (2004) 862 [3] D. 

Mazumdar et al, J. Appl. Phys., 103 (2008) 113911. [4] J. M. Almeida et al, J. Appl. Phys., 105 (2009) 

07E722. [5] K. Fujiwara et al, Jpn. J. Appl. Phys., 50 (2011) 013001 

Oscillatory exchange coupling and strong magnetoresistance effect in 

Fe/AgX/Fe (001) heterostructures with X=Cl and Br 

Petru Vlaic 1 * and Emil Burzo 2 

1 

Biophysics Department, University of Medicine and Pharmacy 'Iuliu Hatieganu' 

400023 Cluj-Napoca, Romania 

2 

Faculty of Physics, Babes-Bolyai University RO-400084 Cluj-Napoca, Romania 

AgCl and AgBr silver halides crystallize under ambient conditions in rock salt geometry having 

lattice parameters epitaxially compatible with Fe structure. AgCl and AgBr compounds are wide 

bang gap semiconductors with indirect band gaps of 3.2 eV and 2.69 eV, respectively. Thus 

Fe/AgX/Fe (001) magnetic tunnel junctions (MTJs) with X=Cl and Br may represent feasible 

heterostructures for comparative studies with sp based Fe/MgO/Fe and Fe/NaCl/Fe junctions 

as well as for spintronic applications. In present contribution structural, electronic and magnetic 

properties of Fe/AgX/Fe (001) MTJs are theoretically investigated by means of a self-consistent 

Green’s function technique for surface and interfaces implemented within tight-binding linear 

muffin-tin orbital (TB-LMTO) method. The spin-dependent transport properties are determined 

by means of Kubo approach implemented within TB-LMTO formalism. Formation of sharp 

Fe/AgCl(AgBr) interfaces and enhancement of interfacial Fe magnetic moments are predicted. 

Metal induced gap states on both anion and cation sites are observed. Oscillatory exchange 

couplings between ferro- and antiferromagnetic states with decreasing amplitude are evidenced. 

Spin-dependent transport properties are determined by the complex band structures of AgCl and 

AgBr barriers. Tunneling magnetoresistance ratios as high as 3500 % are predicted for Fe/AgCl/ 

Fe MTJs in asymptotic regime and even higher values for Fe/AgBr/Fe junctions. 


Poster Friday

Poster Friday 

SK10 


Transport properties in double MgO barrier magnetic tunnel junctions 

with Fe nano-particles 

Pham Van Thach, Do Bang, Shinji Miwa, Takayuki Nozaki, Eiichi Tamura, Norikazu 

Mizuochi, Teruya Shinjo and Yoshishige Suzuki* 

Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560- 

8531, Japan 

Interplay between spin dependent electron tunneling and Coulomb blockade effect [1,2] is one of the 

most attractive subjects in spintronics field because it is expected to give rise to remarkable tunnel 

magnetoresistance (TMR) effect as well as exhibit fascinating phenomena such as Kondo effect[3]. And 

in order to realize this interplay, double barrier magnetic tunnel junctions (MTJs) with ferromagnetic 

nano-paricles are good candidates. In this research, double barrier MTJs with structure of MgO(001) 

substrate/MgO/Cr/Fe/MgO/Fe particles(t = 0.12 - 1.37)/MgO/Fe/Au (unit in nanometer) are fabricated. 

An average diameter of the Fe nano-particles estimated by Langevin function fitting reveals an almost 

linear relation with t for t ≤ 1.02 nm. Coulomb blockade effect was observed for t ≤ 1.02 nm, and the 

t dependence of the Coulomb energy of the Fe nano-particles was explained consistently by a simple 

capacitance model. Interestingly, electron tunneling spectra (dI/dV) and TMR show a dip around zero 

bias at low temperatures. A suppression of the TMR around zero bias implies a phenomenon like Kondo 

physics. The transport properties in the double barrier MTJs having Fe nano-particles were also compared 

with those in a double barrier MTJ with the continuous middle Fe layer and a single barrier MTJ. 

Acknow ledgements: This work is supported by Grant-in-Aid for Scientific Research (S), MEXT, 

Japan. (No. 23226001). [1]. S. Mitani et al. Phys. Rev. Lett. 81, 2799 (1998). [2]. H. Sukegawa et 

al. Phys. Rev. Lett 94, 068304 (2005). [3]. K. I. Lee et al., Phys. Rev. Lett. 98, 107202 (2007). 

SK11 

Characterisation of Epitaxial and Polycrystalline Co2FeSi thin films 

James Sagar 1 , Hiroaki Sukegawa 2 , Leonardo Lari 3 , Vlado K Lazarov 3 , Seiji Mitani 4 

and Atsufumi Hirohata 5 * 

1 

Department of Physics, University of York, United Kingdom 

2 

Magnetic Materials Centre, National Institute for Materials Science (NIMS), 1-2-1 

Sengen, Tsukuba 305-0047, Japan 

3 

Department of Physics, University of York, York, YO10 5DD, United Kingdom 

4 

Magnetic Materials Centre, National Institute for Materials Science (NIMS), 1-2-1 

Sengen, Tsukuba, Japan 

5 

Department of Electronics, University of York, York, YO10 5DD, United Kingdom 

We have grown and characterised both epitaxial and polycrystalline Co 2FeSi thin films using 

UHV magnetron and HiTUS sputtering. The structure of the films has been studied using XRD, 

TEM and STEM. The combination of these techniques allows analysis of the structure and defects 

within the films. Magnetic characterisation has been carried out using AGFM and VSM. UHV 

magnetron sputtered films have been found to become increasingly L 21 ordered after annealing 

above 500°C. HiTUS deposited samples form a polycrystalline film from and amorphous Co, Fe 

and Si matrix after annealing at 500°C for 3, 6 and 9 hours with large (50nm-250nm) L 21 and B 2 

ordered grains. This growth process results in films with large Hc (>500Oe) these values are two 

orders of magnitude greater than those found for epitaxial films [1]. The magnetic response of these 

polycrystalline films has been found to improve with the use of a 6nm Cr or Ag buffer layer. This is 

shown by a decrease is Hc and an increase in Ms to greater than 85% of the theoretical value. 

[1] J.Sagar, et al, IEEE. Trans. Mag, 47, 2440 (2011) 

SK12 

Inverse spin polarization at benzene/iron interface 

Souraya Goumri-said*, Mohammed Benali Kanoun, Udo Schwingenschlogl and 

Aurelien Manchon 

Physical Sciences and Engineering Division, King Abdullah University of Science and 

Technology (KAUST), Saudi Arabia 

Organic spin-valves involving an organic spacer inserted between two magnetic electrodes have 

been successfully realized and led to sizable magnetoresistance ratios [1-3]. The accurate design of 

the interfacial electronic structure controlling the spin injection is critical to obtain high performance 

devices. Intriguingly, recent reports claimed that interfacial spin polarization may be reversed in some 

cases [4, 5]. We address the nature of the spin polarization Benzene/ Fe (100) interface using ab-initio 

approach. The surface is modeled by 6 layers of Fe (100) and the position of the Benzene molecule 

on Fe (100) surface is determined by a combination of the chemisorption of the π-molecule on the 

reactive surface and the strong interaction of the d-metal orbital with π-molecule orbitals. We find that 

the presence of the Benzene molecule dramatically modifies the electronic structure of the interface and 

can lead to drastic change in the interfacial spin polarization. While the Benzene molecule becomes 

slightly magnetic (0.032 μ B by C atom), it is found that the polarization of the interfacial Fermi electrons 

is reversed from 0.59 (pure Fe surface) to -0.70 (Fe/Benzene interface). This polarization reversal is 

analyzed in terms of orbital overlaps between the Benzene p-orbitals and Fe-d orbitals . 

[1] V. Dediu, M. Murgia, F. C. Matacotta, C. Taliani, and S. Barbanera, Solid State Commun. 122, 181 (2002). 

[2] Z. H. Xiong, D. Wu, Z. Valy Vardeny, and J. Shi, Nature 427, 821 (2004); Yoo et al., Nature Materials 

9, 638 (2010) [3] C. Barraud, et al. Nature Physics 6, 615 (2010) [4] Atodiresei et al, Phys. Rev. Lett. 105, 

066601 (2010) [5] M. Saeys, M. Reyniers, and G. B. Marin, J. Phys. Chem. B 106, 7489 (2002). 


SK13 

Local atomic structure analysis of ferromagnetic semiconductor 

GeMnTe by atomic resolution holography 

Naohisa Happo 1 *, Yuki Takehara 1 , Makoto Fujiwara 1 , Koichi Tanaka 1 , Fumihiko 

Matsui 2 , Hiroshi Daimon 2 , Tomohiro Matsushita 3 , Kyoko Okada 3 , Shinya Senba 4 , 

Shinya Hosokawa 5 , Kouichi Hayashi 6 and Hironori Asada 7 

1 

Graduate School of Information Sciences, Hiroshima City University, Japan 

2 

NAIST, Japan 

3 

SPring-8/JASRI, Japan 

4 

Ube National College of Technology, Japan 

5 

Hiroshima Institute of Technology, Japan 

6 


7 

Yamaguchi University, Japan 

The IV-VI diluted magnetic semiconductor GeMnTe is expected as a spintronics material, because it shows a 

ferromagnetic order below 190 K at x = 0.08 [1]. It is believed that its ferromagnetism is a carrier induced type. 

However, another possibility is a cluster formation of a ferromagnetic MnGe binary alloy. The solution can be 

obtained by an investigation of the crystal structure around the each element. Recently, we have investigated 

the atomic arrangement around the Ge and Mn atoms in the GeMnTe by an X-ray fluorescence holography 

(XFH) [2, 3]. The obtained atomic images from the XFH suggest that the Mn atoms replace with the Ge 

atoms in the host GeTe, the Mn position is stable in the exact positions of the anion fcc sub lattice [2], and the 

Ge position is fluctuated [3]. We have also performed the Te 4d photoelectron holography (PEH) in order to 

investigate the local structure around the Te atoms in the GeMnTe thin film single crystal. The obtained atomic 

image from the PEH suggests that the Te atoms are not located at the exact positions of the fcc anion sublattice. 

[1] Y. Fukuma, et al., Appl. Phys. Lett. 93 (2008) 252502. [2] N. Happo, et al., Jpn. J. Appl. Phys. 

50 (2011) 05FC11. [3] N. Happo, et al., e-Journal of Surface and Nano Technology 9 (2011) 247. 

SK14 

Dependence of the tunneling magnetoresistance on the inserted 

nonmagnetic layer 

Changsik Choi and Byung Chan Lee* 

Department of Phyics, Inha University, Korea 

When a crystalline nonmagnetic (NM) layer was inserted between the tunnel barrier 

and a magnetic layer in magnetic tunnel junctions (MTJs), it was observed that the 

tunneling magnetoresistance (TMR) decayed and oscillated as a function of the 

thickness of the nonmagnetic layer. In this paper, the TMR dependence on the NM 

layer is investigated theoretically. The conductance was calculated with the Landauer- 

Buttiker formalism, and the conductance difference between the parallel and antiparallel 

magnetizations was given in an analytical form with the spin-dependent 

reflection amplitudes. In order to check the validity of our model, numerical 

calculations were carried out. An effective mass theory was adopted for the electronic 

structure of each material, and several cases were considered. It was shown that our 

simple model agreed well with the results of the numerical calculations. Our model 

can be applied also to more realistic cases with the full-band structures. The oscillation 

period was determined from the extremal vectors of the Fermi surface of the NM 

material, and the selection rules for the oscillation period were obtained. Comparisons 

with the experimental data and the previous theoretical results will be presented. 

SK15 

The bulk Fe-Mo double perovskite analyzed from a small clusters 

perspective 

Eliel Carvajal Quiroz 1 *, Raul Oviedo Roa 2 , Miguel Cruz Irisson 1 and Oracio Navarro 3 

1 Instituto Politecnico Nacional, ESIME-Culhuacan, Mexico 

2 Programa de Investigacion en Ingenieria Molecular, Instituto Mexicano del Petroleo, Mexico 

3 Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 

Mexico 

Being the Sr 2FeMoO 6 double perovskite among the promising materials for spintronic 

applications, the bulk case was studied in this work; but attention was focused, also, on the 

octahedral arrangements FeO 6 and MoO 6 as well as on FeO 4 and FeMoO 11 clusters. Calculations 

were made using Density Functional Theory (DFT) and the Perdew-Burke-Ernzerhof (PBE) 

functional within the Generalized Gradient Approximation (GGA) scheme. In order to 

understand the differences in the behavior among up- and down-spin electrons observed in the 

half-metallic Sr 2FeMoO 6 double perovskite, the orbitals and density of states were analyzed. Our 

results reveal that the half-metallic character is present ever since the isolated (FeO 6)4- cluster 

and is a consequence of the non-zero spin at Fe atom coming from t2g orbitals. The (MoO 6)6- 

octahedra does not inhibit the perovskite half-metallic character because this Mo-containing 

cluster has a zero total spin. In addition, Sr atoms were aggregated to the studied cluster, not 

just because of the searched relation between the bulk material and the cluster units properties, 

because they give the impression that play a relevant role to become stable the charge even 

though the energy deepest of the states contributed by them. Acknowledgments: Work supported 

by Multidisciplinary Project SIP-IPN: 2012-1439, PAPIIT-IN108710 UNAM.

SK16 

Tunneling magnetoresistance effect in magnetic tunneling junctions 

with a high resistance ferromagnetic oxide Fe 2.5M 0.5O 4(M = Mn, Zn) 

electrode 

Eiji Shikoh 1 *, Teruo Kanki 2 , Hidekazu Tanaka 2 , Teruya Shinjo 1 and Masashi Shiraishi 1 

1 Eng. & Sci., Osaka University, Japan 

2 ISIR, Osaka University, Japan 

Recently, molecular spintronics has attracted much attention. To improve the spin injection 

efficiency from ferromagnetic electrodes into molecular materials, by avoiding an impedance 

mismatch problem, the use of high resistance ferromagnetic electrodes is more accessible than other 

methods. In this study, a high resistance ferromagnetic oxide Fe 2.5M 0.5O 4(FMO: M = Mn, Zn) was 

focused and observation of a tunneling magnetoresistance (TMR) effect in magnetic tunneling 

junctions (MTJs) with an FMO electrode was implemented. MTJs composed of MgO(100)-sub. 

/ FMO(thickness, 25-30 nm) / Al-O(1.5-2) / Ni 80Fe 20(20) were fabricated by using pulsed laser 

deposition, EB deposition, photolithography, Ar ion milling, and sputtering. Magnetic properties 

were investigated with magnetic Kerr effect measurements. Magnetoresistance properties were 

measured with a 4-terminal-method. A TMR effect reflecting the magnetization processes of the both 

ferromagnetic electrodes in the MTJs with M = Mn was successfully observed, and the TMR ratio 

was approximately 0.85% at room temperature (RT) [1]. The spin-polarization of FMO with M = 

Mn at RT was estimated to be at least 0.94%[1]. Higher spin-polarization is expected by improving 

the interface and the barrier qualities between the ferromagnetic electrodes. 

[1] E. Shikoh, et al., Solid State Commun. 151, 1296 (2011). 

SK17 

Monitoring of gamma radiation interaction in PHR sensor 

D.g. Park and Hoon Song 


The Planar Hall Resistance (PHR) sensors have been found to be capable of magnetic 

micro and nano bead detection as the signal to noise ratio in these PHR sensors 

are higher by several orders compared to others magnetoresistive biosensors. In 

addition, the spin valve multilayer are considered as novel structures for a high 

sensitivity and uniform magnetization rotation compared to exchange biased bilayer 

structure for planar Hall resistance sensors.(1). In this work, we discussed a method 

for immobilization of magnetic labels on the PHR sensor for sensitive detection of 

magnetic labels. We used photolithography to generate the functionalized sensor 

surface to demonstrate the capacity of monitoring the immobilization of biomolecule. 

The PHR sensor was irradiated by Co source up to 80 Gy and the sensor characteristic 

was compared with non irradiated one. The field sensitivity obtained by the slope (ΔV/ 

ΔH) of the field-voltage curve was not changed by high dose irradiation up to 80 Gy. 

The sensitivity of the PHR sensor was identified detecting the different concentration of 

magnetic beads. We have successfully demonstrated the immobilization of streptavidin 

coated magnetic bead to the single stranded oligonucleotide on the Au coated PHR 

sensor surface for the detection of magnetic labels. 

[1] P. E. Sheehan and L. J. Whitman, Nano lett. 5, 803 (2005). 

SK18 

Reactively sputtered MgAl2O4 barrier layers for Heusler tunnel 

junctions 

Keima Inagaki*, Naoto Fukatani, Kenichiro Mari, Hirohito Fujita, Tetsuya Miyawaki, 

Kenji Ueda and Hidehumi Asano 


Magnetic tunnel junctions (MTJs) using epitaxial MgO barriers have attracted great interest 

because they exhibit large tunnel magnetoresistance (TMR) ratios. However, the large lattice 

mismatch (about 4%) between MgO and half-metallic Heusler alloy induces misfit dislocations 

and antisite disorder at the surface of ferromagnetic electrode[1]. Thus, coherent growth of MTJ is 

important for further improvement of device performance. This study focuses on spinel MgAl 2O 4 

as a tunnel barrier lattice-matched with half-metallic Heusler alloy. We fabricate a Fe 2CrSi/ 

MgAl 2O 4 junction by reactive sputtering, which can control the crystallinity and degree of 

oxidation of the films strictly, and investigate its crystal structure and electrical transport properties. 

MgAl 2O 4 films were deposited from a MgAl 2 target in Ar + O 2 atmosphere. Epitaxial Fe 2CrSi / 

MgAl 2O 4 junctions were obtained by inserting an ultrathin MgAl 2 interlayer, which worked as a 

protection layer for oxidization at the surface of Fe 2CrSi. The rocking width of MgAl 2O 4 (004) 

was around 1º, which is small value compared to that of the electron-beam evaporated MgO[2]. 

Current-voltage curve was fitted by Simmons’ tunneling theory, and we obtained barrier hight φ = 

0.86-0.95 eV for the Fe 2CrSi/MgAl 2O 4/CoFe MTJ. Present epitaxial MgAl 2O 4 barrier deposited 

by reactive sputtering is expected to realize high performance spintronic devices. 

[1]T. Miyajima, M. Oogane, Y. Kotaka, T. Yamazaki, M. Tsukada, Y. Kataoka, H. Naganuma, and Y. Ando: Appl. Phys. Express 2 

(2009) 093001. [2]G. X. Miao, Y. J. Park, and J. S. Moodera: Phys. Rev. Lett., 100 (2008) 246803. 

SK19 

SK20 

SK21 


Half-metallic properties of (001) surfaces of the Cr substituted rocksalt 

GeTe-based compounds 

Kalpana Kamalkishor Landge, Beata Bialek and Jae Il Lee* 

Physics, Inha university, Korea 

Much effort has been devoted to the development of new magnetic materials for the 

spintronic applications. Recently, new half-metallic ferromagnets based on the rock-salt 

semiconductor GeTe were found [1]. In the bulk structure, GeTe becomes half-metal 

when some of Ge atoms are substituted by Cr or V. We report the properties of (001) 

surfaces of Cubic CrGe 3Te 4 and tetragonal CrGeTe 2 with two different terminations, 

i.e. GeTe and CrTe terminations, as obtained by using the FLAPW [2] within GGA. 

We found that both CrTe- and GeTe-terminated CrGe 3Te 4 and CrGeTe 2 (001) surfaces 

conserve the half-metallic properties of their bulk structures by analyzing the DOS and 

confirmed from the integer value of total magnetic moment (MM) per unit cell. The 

center layer energy gap is much larger as compared to its bulk. The energy gap and half 

metallic gap became wider with the larger substitution of Ge atom by Cr atoms. In the 

CrTe-terminated surface the MM of the Cr atom at the surface layer has been enhanced 

as compared to the center layer Cr atoms by the surface effect. The calculated value of 

MM on Cr at the top layer of the surfaces is 3.7 μ B in the both system. 

[1] Y. H. Zhao, W. H. Xie, L.F. Zhu, and B. G. Liu, J. Phys.: Condens. Matter 18, 10259 (2006). [2] E. 

Wimmer, H. Krakauer, M. Weinert, and A. J. Freeman, Phys. Rev. B 24, 6864 (1981), and references 

therein ; M. Weinert, E. Wimmer, and A. J. Freeman, Phys. Rev. B 26, 4571 (1982). 

Electronic structure and spin polarization of Co 2-xFe 1+xSi Heusler alloy 

Hiroyoshi Itoh 1 * and Syuta Honda 2 

1 Department of Pure and Applied Physics, Kansai University, Japan 

2 Faculty of Pure and Applied Science, University of Tsukuba, Japan 

We study the electronic structure and spin polarization for Co-based Heusler alloys 

of Co 2-xFe 1+xSi using the first principles calculations to discuss the spin injection 

into semiconductors and paramagnetic metals. Half-metallic Heusler alloys such 

as Co 2MnSi, Co 2FeSi, and Fe 2MnSi are promising materials for spin generator, 

injector, and detector. Recently, epitaxial films of Fe 2MnSi [1] and Co 2FeSi [2] have 

been successfully fabricated on Ge or Si substrates and the spin-dependent transport 

properties have been measured. Obtained results seem sensitive to the degree of 

disorder and the composition of the alloy. In this contribution, we examine composition 

dependence of the electronic structure for Co 2-xFe 1+xSi by performing band calculations 

based on the density-functional theory (DFT) in the generalized gradient approximation 

(GGA) using the projector-augmented wave (PAW) method. It is shown that the spin 

polarization defined by the total DOS decreases from +100% at x=0 and changes the 

sign with increasing Fe composition x because the half-metallicity is lost. However, 

the spin polarization defined by the s-component of DOS (partial DOS) keeps positive 

although it decreases with increasing x from x=0 to x=2. 

[1] K. Hamaya et al.: Phys. Rev. Lett. 102 (2009) 137204. [2] A. Yamada et al.: Appl. Phys. Lett. 96 

(2010) 082511. 

Large enhancement of Kerr rotation of GMR periodic patterns using 

Pt / Co free layer 

Kakeru Wada 1 , Tsukasa Kobayashi 1 , Yuuki Oshino 1 , Hiroshi Ono 2 , Tatsutoshi Shioda 2 , Kenji 

Machida 3 , Ken-ichi Aoshima 3 , Kiyoshi Kuga 3 , Hiroshi Kikuchi 3 , Naoki Shimidzu 3 , Akira 

Emoto 4 and Takayuki Ishibashi 1 * 

1 Department of Materials Science Technology, Nagaoka University of Technology, Japan 

2 Department of Electrical Engineering, Nagaoka University of Technology, Japan 

3 Science and Technical Research Laboratories, Japan Broadcasting Corp, Japan 

4 National Institute of Advanced Industrial Science and Technology, Japan 

Magneto-optical spatial light modulator (MO-SLM) driven by spin transfer switching is a promising device 

for holographic 3D display. However, a small Kerr rotation angle is an issue to be solved to realize the MO- 

SLM. In this paper, we report an enhancement of Diffraction Magneto-Optic Kerr Effect (DMOKE) obtained 

for periodic GMR patterns. A GMR structures with Pt/Co free layer were used in this experiment. The samples 

were patterned into periodic structures with sizes of 5-50 μm and pitches of 10-100 μm. SiO 2 was deposited 

on the etched area after the patterning to obtain flat surfaces. DMOKE of the GMR patterns were measured by 

using a He-Ne laser with a wavelength of 632.8 nm and an incidence of 30°. DMOKE hysteresis loops were 

clearly observed, corresponding to the magnetization reversal of the free layers, and Kerr rotation angles of (1,0) 

and (1,1) diffraction spots were measured to be 0.5°, which is six times larger than a polar Kerr rotation angle 

measured before the patterning. We consider that the large enhancement of DMOKE is due to an interference 

effect occurred in the periodic GMR structures embedded in SiO2. This work was supported by the NICT. 

K. Aoshima et al, Appl Phys Let, 44, 052507 (2007) 


Poster Friday

Poster Friday 

SK22 


Ab-initio and tight-binding calculations of magnetic anisotropy 

phenomena in CoPt 

Jan Zemen 1 , Jan Masek 2 and Tomas Jungwirth 3 

1 School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom 

2 Institute of Physics ASCR v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic 

3 Institute of Physics ASCR v.v.i., Czech Republic & University of Nottingham, United Kingdom 

Ordered CoPt alloys hold potential for applications in high density magnetic recording due to the combination of 

exchange and spin-orbit interactions giving rise to large magnetic anisotropies. Tunneling Magnetoresistance [1] and 

Tunneling Anisotropic Magnetoresistance [2] have been demonstrated in tunneling devices with CoPt electrodes. 

Controlling the spin-orbit coupling (SOC) phenomena is essential as the same anisotropy that ensures thermal 

stability of a memory element makes the writing by external magnetic fields or electric currents challenging. An 

alternative to the spin transfer torque (STT) effect in multi-domain systems is based on current induced polarization 

of the conduction electron spins in structures possessing SOC and lacking inversion symmetry. Switching of a 

ferromagnetic layer induced by in-plane current has been shown recently in a Co-Pt bilayer [3]. Another promising 

way of controlling the magnetic anisotropy via SOC utilizes lattice strains induced by piezo stressors. We study 

SOC effects in strained CoPt multilayer structures using a relativistic full-potential linearized augmented plane-wave 

method. We compare the variations of anisotropies of magnetic total energies (MAE) and density of states (ADOS) 

also to our tight-binding calculations using a realistic Slater-Koster parametrization which provide more practical 

basis for further research of magnetotransport anisotropies in CoPt based nanostructures. 

[1] Gukcheon Kim, Yuya Sakuraba, Mikihiko Oogane, Yasuo Ando, and Terunobu Miyazaki, Appl. Phys. Lett. 92, 172502 (2008). [2] B. G. Park, J. Wunderlich, D. A. Williams, 

S. J. Joo, K.Y. Jung, K. H. Shin, K. Olejnik, A. B. Shick, and T. Jungwirth, PRL 100, 087204 (2008). [3] Ioan Mihai Miron, Kevin Garello, Gilles Gaudin, Pierre-Jean Zermatten, 

Marius V. Costache, Stephane Auffret, Sebastien Bandiera, Bernard Rodmacq, Alain Schuhl, and Pietro Gambardella, Nature 476, 189-193 (2011). 

SK23 

Spin polarization of half-metallic Heusler alloy Co 2MnSi by Andreev 

reflection measurements 

Iduru Shigeta 1 *, Yuya Nishisako 1 , Kohei Harumori 1 , Akinari Okubo 2 , Rie Y. Umetsu 3 , 

Masakazu Ito 1 , Keiichi Koyama 1 , Ryosuke Kainuma 2 and Masahiko Hiroi 1 

1 Department of Physics and Astronomy, Kaghosima University, Japan 

2 Department of Materials Science, Tohoku University, Japan 


We report spin polarization measurements of half-metallic Heusler alloy Co 2MnSi. Heusler 

alloys are regarded as the most promising half-metallic materials for spintronics applications 

because of their high Curie temperature and low coercivity. Recently, large tunneling 

magnetoresistance (TMR) value was experimentally reported from a Co 2MnSi/Al-O/Co 2MnSi 

magnetic tunnel junction (MTJ), which was attributed to the half-metallicity of Co 2MnSi. 

Therefore, we have determined the spin polarization of Co 2MnSi by the Andreev reflection 

technique. Polycrystalline Co 2MnSi samples were fabricated by using a high-frequency 

induction furnace. We have made planar-type junctions by depositing Pb on the polished 

surface of the polycrystalline Co 2MnSi samples. The differential conductance of Co 2MnSi/Pb 

planar-type junctions was measured between 1.5 K and 10K by the lock-in amplifier technique. 

The obtained differential conductance was able to be fitted very well by the modified Blonder- 

Tinkham-Klapwijk (BTK) model. We have found the spin polarization of approximately 50% 

from the analysis of Andreev reflection measurements of half-metallic Heusler alloy Co 2MnSi. 

SK24 

Electronic properties of Co2FexMn1-xSi Heusler alloys studied by hard 

X-ray photoelectron spectroscopy 

A. Gloskovskii 1 , S. Ouardi 1 , G. H. Fecher 2 , S. Thiess 3 , W. Drube 3 , B. Detlefs 4 , T. Kubota 5 , Y. Ando 5 

and C. Felser 2 

1 

Johannes Gutenberg University, Mainz, Germany 

2 


3 

Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany 

4 

ESRF, Grenoble, France 

5 

Department of Applied Physics, Graduate School of Engineering, Tohoku University, Japan 

One major research area where Co 2 based Heusler compounds are investigated is on TMR junctions. 

Fully epitaxial magnetic tunnel junctions (MTJs) with a Co 2YZ thin film as a base electrode and a 

MgO tunnel barrier exhibit high TMR ratios. Quaternary Co2Fe xMn 1-xSi (CFMS) Heusler alloys are 

even more promising because the substitution of Mn by Fe increases the number of valence electrons 

and therefore leads to higher Curie temperatures above 1000 K. Kubota et al. found a maximum 

TMR ratio for Co2Fe xMn 1-xSi (x = 0…1)-CoFe MTJs [1] for Fe fractions of between x=0.4 and 0.6. 

The halfmetallic character disappeared for samples with x≥0.8. The reason of this behaviour is still 

unknown. A B 2 and L 21 site ordered stack of MgO substrate/ Cr [40 nm] buffer layer/ Co2Fe xMn 1-xSi 

[30 nm]/ MgO [2 nm]/ AlO x [1.3 nm] (x = 0, 0.2…1.0) films was studied at beamline P09 at PETRA 

III and beamline ID32 at the ESRF. The hard X-Ray photoelectron spectroscopy studies were 

performed with an excitation energy of 6 keV. It was found that the position of Co 2p core levels and 

the density of states in the valence band region strongly depend on the Fe/Mn ratio. 

[1] Takahide Kubota, Sumito Tsunegi, Mikihiko Oogane, Shigemi Mizukami, Terunobu Miyazaki, Hiroshi 

Naganuma, and Yasuo Ando APL 94 (2009) 122504 


SK25 

Ab-initio calculation of the magnetic properties of bn nanoribbon 

Jeffrey Rufinus 

Science Division, Widener University, USA 

The emerging field of spin electronics (spintronics) has been continuously attracting 

researchers. Substantial theoretical and experimental efforts have been made in the 

quest to find the candidates for future spintronics devices. Recently, the search for 

new spintronics materials has also included graphene-based materials due to the 

theoretical prediction that this type of material may show the half-metallic property. 

Here, we present the results of a density functional theory within a generalized gradient 

approximation study of Boron Nitride (BN) nanoribbon. The objective of this study is 

to determine whether this type of material will be ferromagnetic or antiferromagnetic 

if the width is varied. Our results show that the narrow zigzag shaped BN nanoribbon 

prefers ferromagnetic or antiferromagnetic state depending on the width. Thus, by 

controlling the width (and growth direction) it is possible to manipulate the magnetic 

property of this material. These results are of the scientific interest in exploring the 

magnetic properties of BN-based nanoribbon for future spintronics. 

SK26 

Synthesis and functional properties of polycrystalline Fe3Si-based magnetic tunnel junctions 

Alexander Goikhman 1 *, Galina Kupriyanova 1 , Roberto Mantovan 2 , Andrei 

Zenkevich 3 and Ksenia Maksimova 1 

1 

REC 'Functional Nanomaterials', Imanuel Kant Baltic Federal University, Russia 

2 

Laboratorio MDM IMM-CNR, Italy 

3 

NRNU 'Moscow Engineering Physics Institute', Russia 

Magnetic tunnel junctions (MTJs), consisting of two ferromagnetic (FM) layers separated by ultrathin 

tunnel barrier are key elements in a wide range of spintronic devices, particularly, as bit elements in magnetic 

memories and as reading heads in racetrack memory concept. The improvement of the MTJs tunnel 

magnetoresistance (TMR) might be attained by the selection of the materials with high spin-polarization 

and the appropriate combination of FM electrodes and tunnel barrier [1]. In this work, we discuss the 

applicability of a half-metal Heusler alloy Fe 3Si as an top and bottom electrodes in MTJ, the material which 

has been poorly adopted so far [2,3]. MTJs based on polycrystalline Fe 3Si ferromagnetic (FM) electrodes 

and both SiO 2 and MgO tunnel (~1~3 nm) insulators (TI) have been grown by the combination of pulsed 

laser deposition (using two-laser co-deposition approach) and ion beam assisted deposition techniques. The 

morphology, phase composition and structural properties of individual layers as well as the intermixing and 

chemical reactions at the FM/TI interface have been investigated. The magnetic properties of the trilayers 

and preliminary TMR measurements on Fe 3Si-based MTJs obtained at wide range of temperatures (2-400 K) 

will be presented, aiming at the evaluation of potential of Fe 3Si-based MTJs for spintronics. 

1. S.D. Bader, S.S.P. Parkin, Annu. Rev. Condens. Matter Phys. 2010, 1:71-88 2. Y. Ando, K. Hamaya et al., 

Appl. Phys. Lett. 2009, 94 182105 3. K. Harada, K.S. Makabe et al., J. of Phys.: Conf. Ser. 2011, 266 012088 

SK27 

Half-metallic properties of the (001) surfaces of the half-heusler 

compounds GeKCa and SnKCa 

Lee-hyun Cho 1 , Beata Bialek 1 , Jae Il Lee 1 * and Miyoung Kim 2 

1 Physics, Inha University, Korea 

2 Division of Energy System Research, Ajou University, Korea 

The sp or d0 half-metallic materials have been attracted more and more increasing 

attention. A recent first-principles calculation found that the half-Heusler compounds, 

GeKCa and SnKCa, are half-mtallic [1]. We investigated the magnetic and halfmetallic 

properties of the (001) surfaces of the GeKCa and the SnKCa by using the all 

electron full-potential linearized augmented plane wave method [2] within generalized 

gradient approximation. We considered two different terminations for each compound, 

i. e. Ge (or Sn) and KCa terminations. From the calculated density of states, we 

found that the Ge or the Sn termination reserves the half-metallicity, while the KCa 

termination for both compounds is not half-metallic. The magnetic moments for the 

surface Ge and Sn atoms are much enhanced compared to the bulk values, but the KCa 

surface for both compounds is almost magnetically dead. 

[1] J. Chen, G. Y. Guo, K. L. Yao, and M. H. Song, J. Alloy. Compd. 509, 10172 (2011). [2] E. 

Wimmer, H. Krakauer, M. Weinert, and A. J. Freeman, Phys. Rev. B 24, 864 (1981), and references 

therein ; M. Weinert, E. Wimmer, and A. J. Freeman, Phys. Rev. B 26, 4571 (1982).

SK28 

Half-metallicity in hydrogenated carbon nanotubes 

Kyu Won Lee, Gi-wan Jeon and Cheol Eui Lee* 

Physics, Korea University, Korea 

Zigzag-edge graphene nanoribbons (ZGNRs) show half-metallicity arising from edgelocalized 

electron states under an electric field, enabling fully spin-polarized electrical 

current and thus providing a basis for spintronics. While carbon nanotubes (CNTs), 

obtained by rolling up the ZGNRs, have themselves no edges, edge states have been 

identified in hydrogenated CNTs. Thus, whether or not the CNTs can be half-metallic 

under an electric field becomes an issue of great interest. Here, our density functional 

theory (DFT) calculations show that the edge states in the CNTs are unstable under an 

electric field due to the spin-conserving electron transfer between the edges, but a large 

enough transfer barrier between the edge states, obtained by controlling the adsorption 

patterns, can render the CNTs half-metallic. Our results can be extended to most carbon 

systems thus opening a new route to materials engineering and providing a deeper 

understanding of the electronic properties of π-bond network edges. 

1. Y-W. Son, M. L. Cohen, S. G. Louie, Nature 444, 347 (2006 ). 2. Z. Sljivancanin, Phys. Rev. B 84, 

085421 (2011). 

SK29 

Enhanced perpendicular magnetic anisotropy in Fe/(MgAl 2)OX 

bilayer structures with interface optimization processes 

J.w Koo 1 , S Mitani 2 , H Sukegawa 2 , Z.c Wen 2 , T Niizeki 2 , S Kasai 2 and K Inomata 2 

1 University of Tsukuba, Tsukuba National Institute for Material Science, Japan 

2 National Institute for Materials Science, Tsukuba, Japan 

Ferromagnetic metals (FM) electrodes with large perpendicular magnetic anisotropy 

(PMA) are actively being investigated. Recently PMA arising at the interface between a 

FM and an oxide layer such as CoFeB/MgO [1] and Co 2FeAl/MgO [2] were reported. 

The PMA at which between FMs and oxide barrier materials has attracted much 

attention not only for the STT-MRAM applications but also for spintronic devices 

with electric field control of magnetization. The detailed mechanism of the interface 

PMA is still an open question since the experimental reports, in particular the materials 

examined, are much limited. Here, we report the enhanced PMA in Fe/MgAl 2O X 

structures with the effective perpendicular magnetic anisotropy energy density (Keff) 

~ 3 erg/cm 3 . In the case of an Fe layer with a crystalline (MgAl 2)O X layer, it exhibited 

perpendicular magnetization characteristics, and the value of Keff was increased from 

~ 0 to ~3 erg/cm 3 with increasing annealing temperature. Furthermore, even in the Fe 

layer with amorphous (MgAl 2)O X, a large interface magnetic anisotropy was obtained. 

[1] S. Ikeda et al., Nature Mater. 9, 721 (2010) [2] Z. C. Wen et al., Appl. Phys. Lett. 98, 242507 

(2011). 

SK30 

Graphene nano-ribbon and the ripple effect 

Hsin-han Lee, Kuo-chin Chen and Ching-ray Chang* 

Physics, National Taiwan University, Taiwan 

Graphene is a possible nano-device in the future. There are several experiment and 

theory exhibit that the graphene would generate the ripple in some conditions[1-3], and 

there is a “geometrical effect” on the curved surface with Rashba spin-orbit effect[4]. 

We investigate the transport property and the spin density accumulation on the 

graphene nano-ribbon with the ripple. This research used the non-equilibrium Green 

function(NEGF) of the Landauer formula[5.6] to compute the numerical results for the 

system. 

[1] C. H. Lui, Li Liu, K. F. Mak, George W. Flynn and Tony F. Heinz, Nature 462, 339-341 (2009) 

[2] Daniel Huertas-Hernando, F. Guinea, and Arne Brataas, Phys. Rev. B 74, 155426 (2006) [3] 

Z. Wang and M. Devel, Phys. Rev. B 83, 125422 (2011) [4] T.-C. Cheng, J.-Y. Chen and C.-R. 

Chang , Phys Rev B. 84. 214423 (2011) [5] S. Datta. .Electronic transport in mesoscopic systems'. 

Cambridge University Press, Cambridge (1995) [6] S. Datta. .Quantum Transport: Atom to 

Transistor'. Cambridge University Press, Cambridge (2005). 

SK31 

SK32 

SK33 


Enhancement of spin signal in all-metallic lateral spin valves with halfmetallic 

heusler alloy 

Shinya Kasai, Yukiko Takahashi, Shigeyuki Hirayama, Seiji Mitani and Kazuhiro 

Hono 


A lateral spin valve (LSV), consisting of two ferromagnetic wires connected with 

one non-magnetic wire, is one of the promising devices to convert charge currents to 

pure spin currents, and vice versa. The conversion ratio is, however, still too small, 

because of the large spin absorption in ferromagnetic wires. Recently, Fukuma et al. 

have demonstrated that inserting the MgO barrier between ferromagnetic and nonmagnetic 

wires suppresses the spin absorption, resulting in the enhancement of the 

spin signal[1]. Here, we demonstrate another way, using the half-metallic Heusler 

alloy as ferromagnetic electodes. The devices were fabricated from a film stack of 

SiO 2(2)/Cu(10)/Co 2FeGa 0.5Ge 0.5(25)/Ag(10)/Cr(1) on MgO substrate (unit in nm). 

The non-magnetic wire was made of 100 nm-thick Cu. The typical wire width was 

150 nm, while the distance between two ferromagnetic wires was 350 nm. The nonlocal 

resistance observed is 12.8 mΩ at room temperature that increases up to 44.8 

mΩ below 10 K[2]. These values are much larger than those in typical LSVs made of 

Permalloy and Cu in previous reports, indicating the advantage of the half-metallic 

Heusler alloys as ferromagnetic electrodes in LSV. 

[1]Y. Fukuma, L. Wang, H. Idzuchi, S. Takahashi, S. Maekawa, and Y. Otani, Nature Mater. 10, 527 (2011). [2]Y. 

K. Takahashi, S. Kasai, S. Hirayama, S. Mitani, and K. Hono, Appl. Phys. Lett. 100, 052405 (2012). 

Effect of electron beam rapid thermal annealing on the TMR of 

CoFeB/MgO/CoFeB magnetic tunnel junctions 

Ganesh K Rajan 1 , Shivaraman Ramaswamy 2 *, C Gopalakrishnan 2 and John 

Thiruvadigal 3 

1 


2 

SRM University, India 

3 

Department of Physics and Nanotechnology, SRM University, India 

In this paper, we present our studies on the effect of Electron Beam Rapid Thermal 

Annealing (ERTA) on the structural evolution and related transport properties of 

CoFeB/MgO/NiFe MTJ. The MgO based tunneling junctions were fabricated in a DC- 

RF magnetron sputtering system with a base pressure 2 X 10 -7 mBar. An e-beam gun 

with a 3kV power supply was used to facilitate electron bombardment on the MTJ for 

the purpose of rapid annealing .We observed the evolution of TMR in CoFeB/MgO/ 

NiFe MTJ when subjected to ERTA. The main factor that distinguishes this study from 

other rapid annealing based studies is that the evolution of TMR happened within a 

very short annealing time (20 seconds). We observed an ultrafast crystallization of the 

FM layers of the MTJ which resulted in the evolution of TMR. 

1. S. Yuasa, T. Nagahama, A. Fukushima, Y. Suzuki and K. Ando, Nature Mater., vol. 3, pp. 868 - 871, Dec. 

2004. 2. S. S. P. Parkin, C. Kaiser, A. Panchula, P. M. Rice, B. Hughes, M. Samant and S. H. Yang, Nature 

Mater., vol. 3, pp. 862 - 867, Dec. 2004. 3. R. Cao, T. Moriyama, W. G. Wang, X. Fan, J. Kolodzey, S. H. 

Chen, C. R. Chang, Y. Tserkovnyak, B. K. Nikolic and J. Q. Xiao, IEEE Trans. Mag., vol. 45, pp. 3434 - 

3440, Oct. 2009. 

Preparation of Ti-N films for a capping layer of a CoFeB/MgOmagnetic 

tunnel junction 

Atsushi Sugihara*, Soichiro Osaki and Ryoichi Nakatani 


CoFeB/MgO-MTJ is the most promising system for Spin-RAM because of its high 

tunnel magneto-resistance (TMR) [1]. Recently, perpendicular magnetic anisotropy 

(PMA) which was expected to reduce current density for magnetic switching by spintransfer 

torque (Jc0) down to applicable value (

Poster Friday 

SK34 


Half-Metallic Molecular Wire on Silicon Surface 

Yunhao Lu 1 , Yuan Ping Feng 2 * and Shuo-wang Yang 3 

1 National University of Singapore, Zhejiang University of China, Singapore 

2 National University of Singapore, Singapore 

3 Institute of High Performance Computing, Singapore 

Based on DFT calculations including the molecular dynamic simulations, at first time, 

we describe a feasible reaction path to make a robust half metallic Mo-borine sandwich 

molecular wire on hydrogen-terminated Si(001) surface along [100] direction. The 

wire is chemically bonded to the surface, therefore, it is solid enough against thermoperturbation, 

at least up to room temperature. Meanwhile, the electronic and magnetic 

properties of this molecular wire are tunable via an external electric field (EEF), and 

the wire exhibits multifunctional electronic and magnetic states, which allows it to 

work as a multistep molecular switch or/and multistep information storage component. 

Fantastically, this surface wire seems independent from the underplayed silicon bulk 

even under EEF situations since bulk properties have not been affected. This is because 

the charge transfers are constrained within the wire and the upmost layer Si atoms only. 

All of these features should be meaningful in the applications of molecular electronics 

or spintronics in near future. 

SL01 

Structural and magnetic studies of sol-gel prepared hexagonal 

BaFe12O19 Yat Choy Wong 1 *, Geok Bee Teh 2 , Sun Yung Kim 1 and James Wang 1 

1 

Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, 

Australia 

2 

Division of Chemistry and Biology, School of Arts and Science, Tunku Abdul 

Rahman College, Malaysia 

Barium hexaferrite particles prepared by sol-gel method was characterised 

using X-ray diffraction spectroscopy (XRD), Field emission scanning electron 

microscopy (FeSEM), Superconducting Quantum Interference Device (SQUID) and 

Thermogravimetric analysis (TGA). Nano-sized particles BaFe 12O 19 and Fe 2O 3 were 

obtained after calcination at 8000C. The BaFe 12O 19 microstructure showed an average 

grain size of 200nm and recorded a saturation and remanent magnetisation of 60 and 

35 emu/g, respectively. In addition, a commercially available BaFe 12O 19 was also 

studied. The feature observed was quite distinctive and was mostly in platelets form 

and much larger in size. It has a saturation and remanent magnetisation of 70 and 5 

emu/g, respectively. The poor remanent magnetism of this commercially available 

BaFe 12O 19 was due to large particle size and accompanied by an increased in surface 

area. TGA performed at 1000°C recorded about 1.8% wt loss in the sol-gel prepared 

barium hexaferrite compared with 0.2% as observed in the commercial product. 

SL02 

Magnetization reversal process in antiferromagnetically coupled (Co/ 

Pd)/Ru/(Co/Pd) multilayer dot pattern 

Shunji Ishio 1 *, Yuta Kobayashi 1 , Takashi Hasegawa 1 , Akira Arakawa 1 , Hiromi Sasaki 1 , 

Zhongjie Yan 2 and Xi Liu 2 

1 Department of Materials Science and Engineering, Akita University, Japan 

2 Venture Business Laboratory, Akita University, Japan 

Magnetization reversal process, exchange interaction Hex between layers and 

coercivity in the antiferromagnetically coupled (Co/Pd)/Ru/(Co/Pd) dot patterns were 

studied as a function of dot size. Pd 10.5/[Pd 0.7/Co 0.4] 4/Ru 0.4/[Co 0.4/Pd(1.5 nm)]6 were 

sputtered onto pre-patterned Si substrates. Dot shape was designed to be 100 - 3000 

nm square. Magnetization measurements revealed that top and bottom layers have 

a perpendicular magnetic anisotropy and couple each other antiferromagnetically at 

remanent state. MFM measurement indicated that the magnetic state of each layer 

becomes single domain below side length d=200 nm. Complicated magnetization 

reversal process was observed. The magnetization reversal starts from a nucleation 

of reverse domain at dot edge in the reversal from the↑/↓ (↓/↑) state to the ↑/↑ (↓/↓) 

state, while the coherent rotation type behaviour was found in the ↑/↑ (↓/↓) to ↑/↓ 

(↓/↑) reversal. Hex was about 2.2 kOe in the film and decreases to less than 1 kOe at 

d=100 nm. Coercivity is about 1 kOe for the film and is almost constant independently 

on the dot size. The magnetization reversal process and the dependence of Hex and 

coercivity on dot size are discussed in terms of the structural and magnetic property of 

intermediate Ru layer in patterned dots. 


SL03 

Magnetic properties of mechanically alloyed Fe-Cu particles 

Osamu Kohmoto, Masakazu Uchida and Yasushi Matsushima 

Okayama University, Japan 

Mechanically alloyed powders have metastable structure. In the Fe-Cu phase 

diagram, both the Fe and Cu are known to have quite small solubility in to Cu and 

Fe, respectively, at room temperature. We have prepared x at% Cu-Fe particles by 

mechanical alloying. The starting materials were pure Fe and Cu powers. The crystallite 

sizes of Fe with 700 A for bcc(110) and Cu with 45 nm for fcc(111) decreases below 20 

nm at milling time of 500 h. The 500-h-milled alloys with x=0-30 % Cu show a single 

bcc phase, and the alloys with x=35-100 % Cu show a single fcc phase. Co-existence 

of fcc and bcc phases is not observed at x=30 and 35 %Cu. However, at x=30 at %, 

a slight increase in the mass density deduced by lattice parameter is observed and the 

density jumps by 0.85 g/cm3 at 35 at%. The magnetization at 16 kOe decreases from 

200 emu/g with increasing Cu content, however, it has a sudden decrease at 35at% Cu 

of the phase boundary. The magnetization reaches zero at x=90 % Cu. Coercive force 

increases initially with the Cu content, however, it has a sudden jump at the phase 

boundary. 

SL04 

Temperature dependence of the coercive force of ferromagnetic TM- 

Al-O (TM=Fe, Co) granular films 

Shintaro Nakamura 1 *, Akira Yoshihara 2 , Shigehiro Ohnuma 3 and Tsutomu Nojima 1 

1 


2 

Ishinomaki Senshu University, Japan 

3 

Research Institute for Electromagnetic Materials, Japan 

Temperature development of the coercive force (Hc) of ferromagnetic TM-Al-O 

granular films has been investigated in a temperature range from 290 K down to 5 K. 

Each film is prepared using the magnetron sputtering method. During the depositing 

process, a dc magnetic field was applied parallel to the film surface to induce in-plane 

uniaxial anisotropy. An Fe-Al-O granular film shows no clear in-plane anisotropy 

at 290 K. On the other hand, Co-Al-O films show clear in-plane anisotropy at 290 

K. The Hc of the Fe-Al-O film is found to be almost independent of temperature. 

In contrast that of Co-Al-O films strongly depends on temperature. The Hc of Co- 

Al-O films along the easy axis increases rapidly with decreasing temperature. This 

behavior in the Hc also depends on the Co-concentration. For films with lower Coconcentration 

and larger electrical resistivity, enhancement of the Hc becomes larger at 

the lowest temperature. The Hc of Co-Al-O films shows characteristic behavior at low 

temperatures. It increases with decreasing temperature, following a logarithmic law 

below about 50 K. 

SL05 

Microscopic dipole-exchange theory for magnonic crystal arrays of 

interacting ferromagnetic nanorings 

Jan Borchmann, Hoa Nguyen and Michael Cottam 

Department of Physics and Astronomy, University of Western Ontario, Canada 

A microscopic theory is employed to study magnonic crystals represented by onedimensional 

arrays of ferromagnetic nanorings. The Hamiltonian-based formalism 

includes exchange and dipole-dipole coupling within each ring, the long-range dipolar 

coupling between rings, and an external applied magnetic field. Depending on the 

applied field, as well as the size of the rings and the inter-ring spacing, the array 

elements may be in a vortex, onion (bidomain), or other inhomogeneous magnetization 

state. Numerical results are reported for the magnonic bands and gaps in Permalloy 

nanorings with outer diameter typically 80 to 120 nm, thickness typically 15 to 30 nm, 

and spacing varied between 10 and 100 nm. For low values of the field (e.g., 0.02 T) 

along the length of the array, the vortex state is favored energetically and it is found 

that the magnonic bands are fairly broad and the gaps are relatively small, particularly 

when the spacing is reduced. Conversely, at larger fields (e.g., 0.2 T) favoring the 

onion state, the magnonic bands are narrower and the gaps larger. Varying the inner 

diameter of the rings, as well as the spacing, can control the transition fields between 

the different states, which may be advantageous for device applications.

SL06 

Synthesis and magnetic properties of zinc ferrite nanocrystals and 

their applications 

Yang Yang, Xiaoli Liu, Chin Shen Ong and Jun Ding* 

Materials Science and Engineering, National University of Singapore, Singapore 

We studied magnetic properties of zinc ferrite nanoparticles via thermal decomposition, 

whereas zinc ions partially replace iron ions at A sites with a nominal composition of 

(Zn 0.5Fe 0.5)Fe 2O 4. Our first-principle calculation has shown that Zn ion has significantly 

lower formation energy at A-site compared to the substitution of B-site and an 

enhancement of saturation magnetization of 10-20% is obtained due to the reduction 

of the total magnetic moment of A-site which is antiferromagnetically coupled with 

B-site. The iron and zinc precursors [Fe(acac)3, Zn(acac)2.xH 2O] were used in the 

synthesis of zinc ferrite particles. We have found that a molar ratio of zinc precursor 

to iron precursor of 1:2 is required for the end product of (Zn 0.5Fe 0.5)Fe 2O 4. It has been 

found that magnetization measured at room temperature is dependent sensitively 

on particles. Room temperature magnetization reaches 100.9 emu/g for zinc ferrite 

nanoparticles with an average particle size of 85 nm. The value is significantly larger 

than that of bulk Fe 3O 4 (80-90 emu/g). The as-synthesized zinc ferrite particles with 

an average particle size of 26 nm were selected for magnetic fluid hyperthermia. After 

mPEG surface coating, the particles could be well dispersed in water. A comparative 

high SAR value of 630 W/g was obtained. 

SL07 

Nanocrystallite size-induced changes in the magnetic and transport 

properties of La 1-xCa xMnO 3 (x = 1/8, 3/8, 5/8) manganite 

Yugandhar Bitla and S. N. Kaul* 

School of Physics, University of Hyderabad, Central University P.O., Hyderabad - 

500 046, India 

Magnetization, magnetic hysteresis loops/isotherms, linear and non-linear ac 

susceptibility, electrical resistivity and magnetoresistance measurements have been 

performed on 40 nm nanocrystalline La 1-xCa xMnO 3 (x = 1/8, 3/8, 5/8). Compared to the 

bulk, reducing the crystallite size down to 40 nm results in the following changes. For x = 

1/8 [1], lowers paramagnetic insulating (PMI)- ferromagnetic insulating (FMI) transition 

temperature T_(c) to 143 K, induces the metal-insulator (MI) transition at T_(MI) = 77 

K and charge ordering (CO)/orbital ordering (OO) transition at T_(CO/OO) = 35 K but 

leaves the insulating cluster spin glass transition temperature T_(g), the temperature T_ 

(JT) below which short-range antiferromagnetic (AF) order coexists with OO and the 

spin-wave stiffness at 0 K, D(0) = 35(2) meVA 2 , essentially unaltered. For x = 3/8, lowers 

T_(MI) to 234 K, a second-order (first-order) PMI-FMI phase transition occurs at T_ 

(c) = 273.5 K when the applied magnetic field, H = 0 (H ≠ 0), D(0) retains its bulk value 

[2] 145(5) meVA 2 and T_(CO) reduces to 30 K. For x = 5/8, FM and CO ordering in the 

insulating state sets in at T_(c) = T_(CO) = 270 K and transition to the AF/OO phase 

occurs at T_(AF) = 50 K. 

[1] Y. Bitla and S. N. Kaul, J. Appl. Phys. 111, xxxx (2012) at press. [2] J. J. Rhyne et al., J. Magn. 

Magn. Mater. 226-230, 775 (2001). 

SL08 

Magnetic and magneto-optical properties of bilayered Co/Ni anti-dot 

arrays 

N. G. Deshpande 1 , H. Y. Zheng 1 , J. S. Hwang 1 , S. J. Lee 1 , Y. P. Lee 1 *, J. Y. Rhee 2 and K. 

W. Kim 3 

1 

Physics, Hanyang University, Korea 

2 

Physics, Sungkyunkwan University, Korea 

3 

Information Display, SUN MOON University, Korea 

In this study, we have successfully fabricated bilayered Co/Ni anti-dot arrays using 

photolithography and controlled wet-etching processes. Such a ferromagnetic structure was 

made by sequentially depositing Co (40 nm)/Ni (5 nm) bilayer on a Si substrate. The anti-dot 

patterning with a hole diameter of 1 -m was done only on the upper Co layer, while the Ni 

underlayer was kept uniform. The magnetic properties of anti-dot arrays were investigated by 

using a superconducting-quantum-interference-device magnetometer and by magnetic-force 

microscopy (MFM). The longitudinal Kerr rotation (LKR) of the zeroth- and the first-order 

diffracted beams were measured at an incidence angle of 30°. Significantly, it was observed 

that the LKR of the first-order diffracted beam is nearly 4 times larger than that of the zerothorder 

beam. The simulated results for the hysteresis loops matched qualitatively well with 

the experimentally obtained ones. The MFM images revealed well-defined periodic domain 

structures which can be ascribed to the anisotropies such as magnetic uniaxial anisotropy, 

configurational anisotropy, etc. We observed that the magnetization reversal of such a system 

proceeds through the formation and the annihilation of domains. The observed changes in the 

magnetic properties are closely related to the patterning that hinders the domain-wall motion. 

SL09 

SL10 

SL11 


Diffracted magneto-optical Kerr effect of Co anti-dot structure in 

different arrangements 

H. Y. Zheng 1 , N. G. Deshpande 1 , X. R. Jin 1 , J. Y. Rhee 2 , K. W. Kim 3 and Y. P. Lee 1 * 

1 Physics, Hanyang University, Korea 

2 Physics, Sungkyunkwan University, Korea 

3 Information Display, SUN MOON University, Korea 

To fullfill the increasing requirement for the miniaturization of magnetic materials, the 

effective extraction of information from the nano-scale structures becomes hot issue. Some 

of techniques, such as diffracted magneto-optical Kerr effect (DMOKE), magnetic-force 

microscopy and Lorentz scanning transmission electron microscopy, have been utilized to 

read the magnetic information. As a derivative technique of MOKE, which can be applied in 

describing the magnetic hysteresis loops, the DMOKE provides us more unique performance, 

since the diffracted light is more sensitive to the change of the magnetization distribution in 

magnetic material. Micromagnetic simulation is also a useful method to study the process of 

magnetization reversal. In order to get the distribution of magnetization, the Object Oriented 

Micromagnetic Framework (OOMMF) program with periodic boundary condition was 

employed. By combining DMOKE and the micromagnetic simulation, we can theoretically 

and experimentally get more exact magnetic information. We investigated the transverse 

DMOKE and the magnetization-reversal process in rhombic and square lattice arrangements 

of Co anti-dot structures. The hysteresis loops of the diffracted beams are described by the 

magnetic form factor. The shape of hysteresis loops of the diffractions, especially, at the points 

of inflection of the loop, is expected to indicate a special distribution of magnetization. 

Monodisperse magnetic nanoparticles: effects of surfactant 

concentration on the reaction between Fe(acac)3 and Pt(acac)2 

Komkrich Chokprasombat 1 *, Phimphaka Harding 1 , Chitnarong Sirisathitkul 1 , Pongsakorn 

Jantaratana 2 , Sujittra Chandarak 3 and Rattikorn Yimnirun 4 

1 

School of Science, Walailak University, Thailand 

2 

Department of Physics, Kasetsart University, Thailand 

3 

School of Ceramic Engineering, Institute of Engineering, Suranaree University of Technology, 

Thailand 

4 

School of Physics, Institute of Science, Suranaree University of Technology, Thailand 

Magnetic properties of monodisperse nanoparticles for ultrahigh density recording and biomedical 

applications are sensitive to their shape and size distributions. These attributes are, in turns, dictated 

by several parameters during the synthesis and heat treatments. In this work, monodisperse 

magnetic nanoparticles with size of around 4-5 nm were synthesized by the modified polyol 

process with 1.0 mmol Fe(acac)3 and 0.5 mmol Pt(acac)2 as starting materials. The as-synthesized 

nanoparticles were transformed from their superparamagnetic phase to the ferromagnetic state by 

annealing in argon atmosphere at 570 C for 1 hour. Without any reducing agents, concentration 

of surfactants (oleic acid and oleylamine) of 1.5 - 4.5 mmol affected morphology and magnetic 

properties of the nanoparticles. When 2.5 mmol of each surfactant was used, the as-synthesized 

nanoparticles have the smallest variations in size and shape. However, the higher concentration of 

oleic acid and oleylamine led to a higher coercivity in annealed nanoparticles which are related to 

the size distribution. These results indicated that the appropriate amount of surfactants must be used 

in order to optimize the size distribution and magnetic hysteresis of nanoparticles. 

Hollow MnCO3 and MnSiO3 nanosphares 

Zvonko Jaglicic 1 , Jin Bae Lee 2 , Hae Jin Kim 2 and Janez Dolinsek 3 

1 

Dept. of Physics, Institute of Mathematics, Physics and Mechanics & University of 

Ljubljana, FGG, Slovenia 

2 

Division of Materials Science, Korea Basic Science Institute, Daejeon 305-333, 

Korea 

3 

Condensed Matter Physics, J Stefan Institute, University of Ljubljana, Jamova 39, 

SI-1000 Ljubljana, Slovenia 

Magnetic nanoparticles can be used in many different applications ranging from medicine, 

electromagnetic wave detectors to digital information storage. Hollow nanosphares offers 

additional functionality. For example they show improved electrochemical performance 

for batteries or can be used for drug delivery. We synthesised MnCO 3 and MnSiO 3 

hollow nanospheres with a diameter of few nanometers and thickness of only few atomic 

layers. In the MnSiO 3 hollow nanospheres a small concentration of Mn 3O 4 was detected 

from magnetic measurements. Its strong ferrimagnetic signal at TN = 42 K suppressed 

the signal of intrinsic magnetic properties of MnSiO 3 nanospheres. On the other hand in 

the MnCO 3 nanospheres no Mn 3O 4 was detected which enable us to study their dc and 

ac magnetic properties. The Neel temperature at around 33.5 K is between the reported 

values for MnCO 3 single crystal (34.3 K) and powder sample (31.0 K)[1]. A coercive 

field and remanent magnetization of MnCO 3 nanospheres measured at 5 K are decreased 

in comparison to the bulk system. 

[1] A. Kosterov, T. Frederichs, T. von Dobeneck, Physics of the Earth and Planetary Interiors 154 (2006) 234-242. 


Poster Friday

Poster Friday 

SL12 


Shape-controlled synthesis and magnetic properties of FePt nanocubes 

Mingge Zhou 1 *, Wei Li 2 , Minggang Zhu 2 , Dong Zhou 2 and Yanglong Hou 3 

1 Division of Functional Materials, Central Iron and Steel Research Institute, China 

2 Central Iron and Steel Research Institute, China 

3 Department of Advanced Materials and Nanotechnology, College of Engineering, 

Peking University, China 

In this article, synthesis of monodisperse iron-platinum (FePt) nanoparticles by 

reduction of platinum acetylacetonate followed by thermal decomposition of iron 

pentacarbonyl in the presence of oleic acid and oleylamine stabilizers is reported, 

Particle shape is controlled by the addition of Mo(CO)6, our synthesis yields particles 

with shapes that are close to cubic and their size can be controlled from 7 to 10 nm, In 

order to form FePt film, Then the self-assembly FePt nanocubes were annealed at 700 

°C for an hour did the FePt nanoparticle transform to the fct phase.The phase analysis, 

structure, and magnetic properties were determined by X-ray diffraction (XRD), High 

resolution transmission electron microscope (HRTEM), Scanning electron microscope 

and vibrating sample magnetometer (VSM) techniques. 

SL13 

Magnetic properties of NiO/Ni(OH)2 core-shell nanostructures 

Mangesh B. Mahajan and P. A. Joy* 

Physical and Materials Chemistry, National Chemical Laboratory, Pune, India 

Antiferromagnetic materials show interesting and anomalous properties when their size 

is reduced to nanodimensions. The magnetic susceptibility is increased with decreasing 

particle size(1). Bulk NiO is antiferromagnetic and recent studies showed that NiO 

nanoparticles exhibit aging and memory effects similar to that of spin glasses(2). The 

finite size and surface effects play major role in determining the magnetic behaviour of 

these nanoparticles(3). We have synthesized NiO nanoparticles by a simple chemical 

route followed by calcination. The freshly prepared sample was dispersed in water, 

then filtered and dried in air to get NiO/Ni(OH) 2 core-shell type nanostructures. 

These nanostructures were characterized by using different techniques and magnetic 

properties using SQUID-VSM. Magnetic properties of nanoparticles of NiO, Ni(OH) 2, 

and NiO/Ni(OH) 2 have been compared to study the effect of Ni(OH) 2 layer on NiO. 

Low temperature M-H curves showed considerable difference in the coercivities 

and saturation magnetization values of the core-shell structure. From ZFC and FC 

measurements it is observed that magnetic behaviour of the NiO/Ni(OH) 2 core-shell 

nanoparticles differs substantially from that of bare NiO and Ni(OH) 2 nanoparticles. 

The observed changes are explained in terms of lower size of NiO core and the effect 

of different inter-particle interactions with and without the hydroxide layer. 

1. J. T. Richardson and W. O. Milligan, Phys. Rev. 102, 1289 (1956). 2. S. D. Tiwari and K. P. Rajeev, Phys. Rev. B, 

72, 104433 (2005). 3. R. H. Kodama, Salah A. Makhlouf and A. E. Berkowitz, Phys. Rev. Lett. 79, 1393 (1997). 

SL14 

Structual and magnetic properties of MFe2O4 (M=Ni, Mg) nano hollow 

spheres 

K. Konishi 1 *, T. Sakurai 1 , Y. Nagano 2 , N. Manabe 2 and Y. Morimoto 2 

1 

Department og Physics, Graduate School of Science and Engineering, Ehime 


2 

Department og Physics, Faculty of Science, Ehime University, Japan 

Hollow sphere structures have recently received considerable attention because of 

their novel interior geometry and surface functionality. In this report, sub-micrometersized 

hollow spheres assembled from ferrite nanoparticles have been prepared by a wet 

chemial process. Measurements of dc-susceptibility and magnetization were carried 

out on samples of MFe 2O 4 (M= Ni, Mg) nanoparticles with average diameter 4-5 

nm, and hollow spheres (500 nm in diameter) with about 12-17nm thickness shell. A 

superparamagnetic-type blocking process is observed in the ZFC and FC magnetization 

and magnentic susceptibility for all samples. Furthermore, a behavior due to surface 

spin freezing of nanoparticles is found in Ni-ferrite. The surface spin freezing 

temperatures Tf are quite lower than the blocking temperature, and the magnetic field 

dependence is different between nanoparticle and hollow sphere. The spin-glass nature 

of Ni-ferrite nanoparticle is demonstrated by the magnetice field dependence of Tf 

following the well known Almeida-Thouless line. In contrast, Tf (H) of Ni-ferrite 

hollow sphere hints at failure of Gabay-Toulouse theory as well as the AT type. 


SL15 

Magnetization reversal in patterned arrays of (001)Fe particles 

Maj Hanson 1 *, Rimantas Brucas 2 and Erik Wahlstrom 3 

1 Department of Applied physics, Chalmers university of technology, Sweden 

2 Department of Engineering Science, Solid State Physics,, Uppsala University, 

Sweden 

3 Institutt for fysikk, NTNU, Norway 

Arrays of elliptical Fe particles prepared by patterning [1] of epitaxial (001)Fe films 

may serve as model systems for studies of the processes of magnetization reversal in 

sub-micron size particles. In this work we studied such systems with film thicknesses 

in the range between 10 nm and 50 nm. Ellipses with aspect ratio 1:3 were prepared 

with their short axes being 50, 100 and 150 nm and varying inter-particle distances. 

The magnetic domain state and the magnetization reversal of individual particles were 

investigated by magnetic force microscopy (MFM) and micromagnetic calculations. 

Magnetization curves of the arrays, comprising about 106 particles, were measured 

with an alternating gradient force magnetometer (AGM). Within the range of actual 

sizes we find that the largest particles may be left in a multi- or bidomain (MD) state 

after demagnetization whereas the smallest show single-domain (SD) properties. In 

particular we analyze the influence of interactions and the transition from MD to SD 

behaviour as displayed in the shape of the hysteresis curves and in the MFM images 

taken after remanent demagnetization. The single particle properties are compared with 

results from micromagnetic calculations. 

1. M. Hanson et al. JAP 85 (1999) 2793 

SL16 

Controllable structure and magnetic properties of cobalt nanowires by 

tuning deposition voltage 

Xiu Xiu Fan 1 , Hai Ning Hu 2 and Zhong Shi 3 * 

1 

Surface Physics State Laboratory and Department of Physics, Fudan University, 

China 

2 

School of Mathematics and Physics, Shanghai University of Electric Power, China 

3 

Department of Physics, Tongji University, China 

Magnetic properties of Co nanowires have been shown to be controlled by various growth parameters. The 

deposition voltage shows great convenience in controlling microstructure. Reported results were mostly 

focused on low voltages[1-4]. In this work, Co nanowires were fabricated into ordered AAO templates by dc 

electrodeposition in a wide range of deposition voltage at 20°C. With deposition voltages of 2.0 and 4.5 V, Co 

nanowires are of hcp(100) and fcc(220) along the nanowire-axis, respectively. Two structures coexist for medium 

voltages. For all samples, the easy axes of magnetocrystalline (Kmc) and shape (Ksh) anisotropy make angles to 

each other. For low voltages, Kmc and Ksh are close to each other, resulting in small coercivity Hc(||) and Hc(┴) 

for H parallel and perpendicular to nanowire-axis. Since Kmc is one order smaller than Ksh and thus the easyaxis 

lies along the nanowire-axis for high voltages, large Hc(||) is obtained at room temperature. For low and high 

voltages, Hc(||) first decreases and then increases with a minimum at 200 K, and increases monotonically with T 

increasing from 50 to 390 K[5], respectively. The angular dependence of Hc shows a combined magnetic reversal 

process which can be described by curling and/or transverse domain wall modes[6]. 

1. H. Zeng, R. Skomski, and et al., Phys. Rev. B 65, 134426 (2002). 2. H. Zeng, M. Zheng, and et al., J. Appl. Phys. 87, 4718 (2000). 3. H. Pan, B. Liu, 

and et al., J. Phys. Chem. B 109, 3094 (2005). 4. X. H. Han, Q. F. Liu, and et al., J. Phys. D: Appl. Phys. 42, 095005 (2009). 5. J. Sanchez-Barriga, M. 

Lucas, and et al., Phys. Rev. B 80, 184424 (2009). 6. M. Vazquez and L. G. Vivas, physica status solidi (b) 248, 2368 (2011). 

SL17 

Magnetotransmission effect in Nd 0.5Sr 0.5MnO 3 nano-composites 

Elena Mostovshchikova, Natalya Loshkareva, Andrey Telegin*, Nikolay Solin, 

Sergey Naumov and Sergey Telegin 

Institute of Metal Physics UD of RAS, Russia 

Magnetic and optical properties of composites on the base of Nd 0.5Sr 0.5MnO 3 powders diluted in dielectric 

matrix have been studied. Nd 0.5Sr 0.5MnO 3 manganite is interesting due to existence of two different type 

of phase transitions: the first one is from paramagnetic semiconductor to the FM metallic state near TC- 

250 K, the second one is from the FM metallic state to CE-type AFM insulating state with charge ordering 

near TCO-160 K [1]. The giant negative magnetotransmission effect (relative change of natural light 

transmission under the magnetic field) up to 14% in the field H = 0.8 T was revealed for Nd 0.5Sr 0.5MnO 3 

composites near TC in the infrared range. The charge ordering and AFM state may by destroyed by 

decreasing of grains to nanoscale size [2] resulting in appearing of new effects. The remarkable feature 

of Nd 0.5Sr 0.5MnO 3 nano-composite with average grain size about 100 nm is an existence of significant 

magnetotransmission about 7% in the wide temperature range near and far below TC. It was explained 

by the significant contribution of nano-particle shells with disordered spins to the magnetic properties of 

nano-composite. Finally, such a composite material is a promising candidate for future magneto-optical 

applications [3]. 

[1] H. Kawano, R. Kajimoto, H. Yoshizawa, Y. Tomioka, H. Kuwahara, and Y. Tokura. Phys. Rev. Lett. 78, 4253 (1997) 

[2] R.H. Kodama. JMMM 200, 359 (1999); R.H. Kodama and A.E. Berkowitz. Phys. Rev. B 59, 6321 (1999) [3] A.B. 

Granovskii, Yu.P. Sukhorukov, A.V. Telegin et al, J. of Experimental and Theoretical Physics, 112, No1, 77 (2011) 

Supported by the program of DPS RAS “Physics of new materials and structures”, grant MK-1048.2012.2 and RFBR 

grants No 10-02-00038, 11-02-00252, 12-02-00208

SL18 

Influence of asymmetric permalloy ring on magnetization 

configuration and switching behavior 

Chao-hsien Huang 1 *, Lance Horng 1 , Nian-jia Cheng 2 , Tian-chiuan Wu 3 and Jong-ching Wu 1 

1 Department of Physics, National Changhua University of Education, Taiwan 

2 Institute of photonics, National Changhua University of Education, Taiwan 

3 Department of Electronic Engineering, National Formosa University, Taiwan 

By introducing an inner circle shifted along the diameter of outer circle, an asymmetric ring and the 

asymmetric ratio (R) are defined to control over the vortex state (flux-closure state) nucleation and 

annihilation field in asymmetric Permalloy (Py) rings. Series of asymmetric Permalloy rings with 

different diameter and asymmetric ratio were prepared to observe the magnetic switching behavior 

and the magnetization configuration. The asymmetry of Py rings with thickness of 20 nm, outer 

diameter (Do) of 300, 500, 800 nm, inner diameter (d) of 100, 150, 200, 250, 300 nm, and shift 

length (S) of 30, 50, 70, 100, 120, 150 nm. Numerical micromagnetic simulations are carried out 

using the object-oriented micromagnetic framework (OOMMF) software. With applied field from 

the positive to negative magnetic field, the magnetic field at which the vortex nucleate in the Py ring 

is defined as the nucleation field (Hn). The annihilation field (Han) is the magnetic field where the 

vortex annihilate. Linear relations of vortex state nucleation and annihilation fields to asymmetric 

ratio were found, and are useful mainly for controlling the nucleation and annihilation fields. 

1. P. Vavassori, R. Bovolenta, V. Metlushko and B. Ilic, J. Appl. Phys. 99, 053902 (2006) 2. E. Saitoh, M. Kawabata, K. 

Harii, H. Miyajima and T. Yamaoka, J. Appl. Phys. 95, 1986 (2004) 3. X. H. Wang, W. K. Peng, and W. S. Lew, J. Appl. 

Phys. 106, 043905 (2009) 4. A. Subramani, D. Geerpuram, V. Baskaran, J. Friedlund, and V. Metlushko, Physica C 437- 

438, 293 (2006) 5. F. Giesen, J. Podbielski, B. Botters, and D. Grundler, Phys. Rev. B 75, 184428 (2007) 

SL19 

Fabrication of high aspect ratio nanoscale magnetic tunnel junction 

etch mask by oxygen plasma assisted resist trimming 

Bongho Kim 1 , Daehong Kim 1 , Sungwoo Chun 1 , Hyungyu Lee 1 , Seonjun Choi 1 and 


1 Department of Electronic Engineering, Hanyang University, Seoul, Korea 

2 Department of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, 

Korea 

The development of large-area, nanostructure patterning with high aspect ratios is a challenging 

problem that must be addressed for potential applications in high performance nanoscale devices[1]. 

When negative resist pillar patterns are formed using electron beam lithography,the forward and 

backward scattering of the electrons limit the resolution therefore, the resist layer should be thinner. 

When the patterned resist pillars were used as dry etching masks, the resist polymer during the 

process requires the pillars to have high aspect ratio. Also,due to chemical processing, high aspect 

ratio resist pillars have a high probability of falling over due to capillary forces on the pillars[2]. 

We report on a simple method to overcome the low aspect ratio and the collapse of resist by using 

oxygen plasma assisted resist trimming.Firstly,We used 170 nm thick negative electron beam resist 

and patterned 55 nm dot arrays using 80 kV electron-beam.Next, resist trimming process was done 

using oxygen plasma ashing at 50 W and 0.1 Torr for 70 seconds.This process resulted in 5 nm 

trimming in all direction. Therefore the 70 s ashing resulted in a 30 nm diameter and 145 nm tall 

resist pillar increasing the aspect ratio from 3 to 5, which is about 70 % increase. 

[1] Hwan-Jin Jeon, Kyoung Hwan Kim,. Nano Lett. 2010, 10, 3604-3610 [2] Toshihiko 

TANAKA,Mitsuaki MORIGAMI,Nobufumi ATODA,. Jpn. J. Appl. Phys. Vol. 32 (1993) PP.6059-6064 

SL20 

Magnetic properties of iron(III) oxide nanostructures by hydrothermal 

synthesis 

Raquel A Ribeiro*, Allan M Xavier and Flavio L Souza 

Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC - UFABC, 

Brazil 

The hydrothermal synthesis of nanoparticles enables functional control on the 

distribution of particle size, morphology and crystallinity by controlling the synthesis 

parameters. The synthesis of nanoparticles of iron oxide by this method was performed 

by raising the temperature of a autoclavable bottle containing a solution of iron(III) 

chloride, sodium nitrate and hydrochloric acid in appropriate quantities. Iron oxide 

powders synthesized under conditions previously published in the literature were 

treated in a box furnace at temperatures of 390, 450, 550 and 800 °C. For these samples 

we performed structural, morphological and magnetical characterization. The images 

of transmission electron microscopy provide evidence that the 1D nanostructures 

of iron(III) oxide, are joined by surfaces with non-oriented crystallographic planes, 

suggesting that the growth of these particles occurs by oriented coalescence. After 

heat treatment a phase transition occurs from akaganeite to hematite. Magnetization 

measurements show that akaganeite presents weak magnetic behavior, whereas the 

hematite phase presents a larger remnant magnetization and coercive field. We thank 

the support of Brazilian agencies FAPESP and CNPq. 

SL21 

SL22 

SL23 


Magnetic dot-antidot lattice for control of magnetic anisotropy 

Sadashivaiah Sakshath*, Kalappattil Vijaysankar, Karki S Bhagyashree, Subray V 

Bhat and P. S. Anil Kumar 

Department of Physics, Indian Institute of Science, Bangalore, India 

The magnetic anisotropy of epitaxial Fe/GaAs(100) films varies with thickness of 

the film.[1, 2] We have prepared rectangular lattices of antidots using epitaxial 35 

monolayer (ML) Fe/GaAs(100) films deposited by Pulsed laser deposition in an 

ultrahigh vacuum chamber whose base pressure was less than 2exp(-10) Torr. 10ML 

MgO/35ML Fe/GaAs(100) film was controllably etched to reduce the thickness of 

lithographically defined regions of the Fe film to 19ML and capped with MgO before 

liftoff. Thus square antidot regions of size 200nm containing Fe of thickness lower 

than the surrounding matrix were created. Thus we have created a 2 dimensional 

magnetic system having a uniform material composition but controlled lateral variation 

of local magnetic anisotropy. The spacing between the antidot regions is varied from 

~ 200nm to 400nm. Investigations of magnetic anisotropy on the dot-antidot bilayer 

were performed using Magneto-Optical Kerr effect in longitudinal configuration and 

Ferromagnetic Resonance. Anisotropy constants are evaluated and it shows that the 

ratio of the magnitude of the uniaxial anisotropy to the magnitude of the four fold 

anisotropy is much higher (0.96) in the dot-antidot bilayer even with a square lattice. 

This is discussed in terms of exchange coupling between the antidot region and the 

surrounding matrix. 

[1] G. Wastlbauer and J. A. C. Bland, Adv. Phys. 54, 137 (2005) [2] S. Sakshath et al, J. Appl. Phys. 109, 07C114 (2011) 

Effect of diameter of the wires on magnetic properties of 

electrodeposited CoNiP hard magnetic nanowires 

Tuan Tu Le 1 *, Pham Hong Quang 1 , Luu Van Thiem 2 , T.s. Ramulu 3 and Cheolgi Kim 3 

1 

Faculty of physics, University of Science, Vietnam National University, 334 Nguyen Trai, Thanh 

Xuan, Hanoi, Vietnam, Viet Nam 

2 

Faculty of Engineering Physics and Nanotechnology, College of Technology, Vietnam National 

University,144 Xuan Thuy, Caugiay, Hanoi, Vietnam, Viet Nam 

3 

Deparment of Materials Science and Engineering, Chungnam National University, Daejeon 305- 

764, South Korea, Korea 

The magnetic properties in CoNiP nanowires arrays with diameter of nanowires in range of 50-800nm 

were investigated. All the samples were prepared by electrodeposition method with pH of 3.1 and room 

temperature. The electrochemical potential of CoNiP were determined by cycle voltammetary. The crystalline 

structure and morphology of the samples were characterized by X-ray diffraction (XRD) and Scanning 

Electron Miroscopy (SEM), respectively. The hysteresis loops were measured at room temperature using 

vibrating sample magnetometry (VSM) and alternating gradient magnetometry (AGM) with magnetic field 

applied perpendicular and parallel to the wire axis. The mixture of fcc and hcp polycrystalline phases of the 

CoNiP based nanowires has been indicated by the XRD pattern. The obtained results show that with 800 nm 

of diameter of the nanowires we can obtain maximum coercivity value (2070 Oe). The uniaxial anisotropy 

values dependent on diameter of the wires are calculated. The anisotropy of the samples are quasi-onedimensional 

anisotropic is also found when diameter of the wires are less than 500 nm. 

[1] A. Fert, L. Piraux, Journal of Magnetism and Magnetic Materials 200 (1999) 338 [2] Shan Guan and Bradley J. Nelson, Journal of The Electrochemical Society, 152 (4) 

(2005) C190 [3]R.N. Emerson, C. Joseph Kennady, S. Ganesan, Thin Solid Films 515 (2007) 3391 [4] P. Cojocaru, L. Magagnin, E. Gomez, E. Valles, Journal of Alloys and 

Compounds 503 (2010) 454 [5] Takanari Ouchi, Naofumi Shimano, Takayuki Homma, Electrochimica Acta 56 (2011) 9575 

Switching behavior of lithographically defined grid of permalloy 

nanowires studied with magnetoresistance 

Venkateswarlu Dasari, Vineeth Mohanan Parakkat and Anil P. S. Kumar 


We report the switching behavior of a grid [1] of permalloy nanowires fabricated using 

e-beam lithography and DC-magnetron sputtering followed by lift-off process. The 

wires are of 20 nm thickness and about 120 nm wide. The periodicity between the 

wires is maintained at one micron throughout the grid. The grid is made as a Hall bar 

geometry which consists of few hundreds of junction regions. The magnetoresistance 

study indicate that the node regions in the grid acts as defects in the horizontal wires 

in longitudinal magnetic field, which in turn leads to the nucleation of domains. Thus, 

the switching process in the horizontal wires is governed by these defect centers 

[2]. The switching field varies from 80 Oe to 140 Oe for transverse to longitudinal 

magnetoresistance. The non zero coercivity (80 Oe ) in transverse magnetoresistance is 

due to the presence of nodes. These nodes possess four-fold anisotropy with easy axes 

along the diagonal directions. Further, the micro-magnetic simulations using Object 

Oriented Micro Magnetic Framework (OOMMF) with the two dimensional periodic 

boundary condition, gives the information about the domain configuration which 

supports our experimental findings. 

1. S. P. Li, A. Lebib, D. Peyrade, M. Natali, Y. CheN, W. S. Lew and J. A. C. Bland J. Appl. Phys. 90, 

521 (2001) 2. A. O. Adeyeye and M. E. Welland, J. Appl. Phys. 92, 3896 (2002) 


Poster Friday

Poster Friday 

SL24 


Magnetization reversal modes in narrow FePt nanowires with high 

perpendicular anisotropy 

Van Dai Nguyen 1 , Laurent Vila 1 , Matthieu Tissier 2 , Alain Marty 1 , Murat Cubukcu 1 , Piotr 

Laczkowski 1 , Williams Savero-torres 1 , Juan-carlos Rojas Sanchez 1 and Jean-philippe Attane 1 

1 Universite Joseph Fourier, BP 53, 38041, Grenoble and INAC/ CEA Grenoble, France 

2 LPTMC, CNRS-UMR 7600, Universite Pierre et Marie Curie, boite 121, 4 Pl. Jussieu, 75252 

Paris Cedex, France 

In this contribution, we present the dependence of magnetization reversal modes in FePt nanowires with 

the width ranging from 2000 nm to 30nm using magneto-transport and magnetic force microscopy (MFM) 

measurements. Magneto-transport measurements showed an enhancement of magnetic coercivity when 

reducing the width. Theoretical calculations suggest that this coercivity increase is not only due to the 

suppression of available propagation paths but also to the contribution of the roughness. Further study 

of the magnetization reversal process using MFM shows that three different reversal modes can appear. 

Indeed, for widths above 500 nm, the structure of the reversed magnetic domains appears to be similar to 

those of the continuous FePt film: the reversed magnetic domain grows and expands within a dendritic 

structure. For widths below the characteristic dendrite width (~300 nm), the reversal takes place by 

propagation of a single DW that reverse the whole wire. Finally, we show that another behavior appears 

at very low widths: when reducing the widths below 50 nm, the propagation field becomes larger than 

the nucleation field. Nucleation thus occurs randomly, the reversal consisting in a mix of nucleation and 

propagation. Such behavior could prevent the use of ultra-narrow wires for DW-based spintronic devices. 

J. P. Attane et al., Phys. Rev. B, 84, 144418 (2011) J. P. Attane et al., Phys. Rev. B, 82, 024408 (2010) 

SL25 

Structural and magnetic behaviour of nanocrystalline CaFe 2O 4 

S. N. Dolia*, Arvind Samariya, Arun S. Prasad, P. K. Sharma, M. S. Dhawan and S. P. 

Pareek 

Department of Physics, University of Rajasthan, Jaipur, India, India 

Abstract. Study of the structural and magnetic properties of the nanoparticles of large 

cation substituted ferrite, CaFe 2O 4 have been reported here. The cubic spinel phase of 

CaFe 2O 4 could be synthesized effectively in nanocrystalline form of size 5.9 nm using 

advanced sol-gel method. The sample was then heated at 1000 °C leading to bulk 

size of orthorhombic structure. Very interestingly, the nanoparticles of CaFe 2O 4 get 

transformed from cubic spinel structure to its characteristic orthorhombic structure on 

annealing at 1000 0C. Rietveld profile refinement of the XRD patterns was performed 

to study the nature of crystal structure. The SQUID magnetization measurements 

divulged that the nanocrystalline sample is superparamagnetic above the blocking 

temperature of 150 K whereas the bulk sample is ferromagnetic even at room 

temperature. The reduction in saturation magnetization in the case of nanoparticles 

as compared to its bulk counterpart has been explained on the basis that the magnetic 

moments in the surface layers of a nanoparticle are in a state of frozen disorder. The 

departure of the field cooled curve from the zero field cooled curves in the momentversus-temperature 

plot, further confirmed the room temperature superparamagnetic 

behavior of the nanocrystalline CaFe 2O 4. 

SL26 

Magnetoresistance of helimagnetic ordering in single crystal FeGe 

nanowires 

Tae-eon Park 1 , Byoung-chul Min 1 , Dong-jea Seo 2 , Younho Park 1 , Heon-jin Choi 2 and 

Joonyeon Chang 1 * 

1 Spin Device Research Center, KIST, Korea 

2 Deparment of Materials Science and Engineering, Yonsei University, Korea 

We report on the synthesis, structural characterization, and magneto-transport of single 

crystalline FeGe NWs. Transition metal silicides and germanides have attracted a lot of 

attention because of their chiral cubic helimagnetism as a consequence of the Dzyaloshinskii- 

Moriya interaction. FeGe is known to have a high Neel temperature and helical spin order 

with a relatively long period. In addition, one dimensional-confinement of the spin structure 

might enhance the helical magnetic ordering of FeGe NWs as the nano-confinement often 

alter or improve the properties. We have synthesized single crystalline FeGe NWs by CVD 

process without any catalyst. We have investigated the helimagnetic ordering in FeGe NWs by 

using electrical and magneto-transport measurements. When the magnetic field was applied 

longitudinal to the NW axis, the signature of the helimagnetism in the FeGe NWs was observed 

up to near room temperature. The magneto-transport measurements reveal three magnetic states 

of the FeGe NWs: the helimagnetic state, conical helimagnetic state, and ferromagnetic state. 

The magnetic transitions from the conical helimagnetic state to ferromagnetic state in FeGe 

NWs was clearly observed and occurred at much higher field those observed in the bulk FeGe. 

The relationship between nano-sized confinement and the conical helimagnetic state will be 

discussed in detail. 


SL27 

Arrays of interacting ferromagnetic nanofilaments: small-angle 

neutron diffraction study 

Natalia Grigoryeva 1 *, Sergey Grigoriev 2 , Arseniy Syromyatnikov 2 , Andrey 

Chumakov 2 , Helmut Eckerlebe 3 , Kirill Napolskiy 4 , Ilya Roslyakov 4 and Andrey 

Eliseev 4 

1 Faculty of Physics, Saint Petersburg State University, Russia 

2 Konstantinov Petersburg Nuclear Physics Institute, Russia 

3 Helmholtz Zentrum Geesthacht, Germany 

4 Moscow State University, Russia 

Magnetic properties of spatially ordered arrays of interacting nanofilaments have been studied 

by means of small-angle diffraction of polarized neutrons. Several diffraction maxima or rings 

that correspond to the scattering of the highly ordered structure of pores/filaments with hexagonal 

packing have been observed in neutron scattering intensity maps. The interference (nuclear-magnetic) 

and pure magnetic contributions to the scattering have been analyzed during the magnetic reversal 

of the nanofilament array in a field applied perpendicular to the nanofilament axis. The average 

magnetization and the interference contribution proportional to it increase with the field and are 

saturated at H = Hs. The magnetic reversal process occurs almost without hysteresis. The intensity 

of the magnetic contribution has hysteresis behavior in the magnetic reversal process for both the 

positive and negative fields that form the field dependence of the intensity in a butterfly shape. It has 

been shown that this dependence is due to the magnetostatic interaction between the filaments in 

the field range of H ≤ Hs. A theory for describing the magnetic properties of the arrays of interacting 

ferromagnetic nanofilaments in the magnetic field has been proposed. 

SL28 

Magnetic properties of nanometer scale FeCr antidot array system 

Shivaraman Ramaswamy and Geo George Philip 


In this work, we have fabricated periodic nanometer scale antidot array of FeCr. The deposition was 

done using electron beam evaporation. The substrate was first coated with 100nm of a suitable resist 

(ZEP-520A) using spin coating. Then, the mask was patterned on the substrate using an electron 

beam attached to field emission scanning electron microscope to generate the necessary pattern. 

After the development, the FeCr (40nm) was coated onto the resist at 0.1A/s using electron beam 

evaporation. The antidot pitch was maintained at 400nm and the antidot diameter was found to be 

300nm. The magnetic nature of the sample was characterized using vibrating sample magnetometer 

and the in-plane magnetic anisotropy of the system was investigated using torque magnetometer. 

Further, the magnetoresistance measurements were taken using an inline four point probe. The results 

indicate that the antidot array system has a predominant ferromagnetic nature, has an n-fold rotational 

symmetry with relation to the magnetic anisotropy. The easy axis, the hard axis of magnetization 

along with the net anisotropic energy has also been determined. All data have been appropriate 

discussed in the work. The use of antidot array systems for various applications is an intriguing new 

area of research. 

E.R. Spada, G.M.C. Pereira, E.F. Jasinski, A.S. da Rocha, O.F. Schilling, M.L. Sartorelli. Anisotropic magnetoresistance 

in electrodeposited cobalt antidot arrays. Journal of Magnetism and Magnetic Materials 320 (2008) 253-256. L.J. 

Heyderman, S. Czekaj, F. Nolting, D.H. Kim, P. Fischer. Cobalt antidot arrays on membranes: Fabrication and 

investigation with transmission X-ray microscopy. Journal of Magnetism and Magnetic Materials 316 (2007) 99-102. M. 

Tanaka, K. Itoha, H. Iwamotoa, A. Yamaguchia, H. Miyajimaa, T. Yamaokab Magnetic properties of nanometer-scale FeNi 

antidot array system. (2006). 

SL29 

Fabrication of Al-Ni core-shell structured particles via electroless ni 

plating 

Youn-kyoung Baek*, Jung-goo Lee, Sangsun Yang and Chul-jin Choi 

Powder & Ceramic Research Division, Korea Institute of Materials Science, Korea 

Al alloy powders have been of much interest in recent years due to their various 

applications such as metallurgical, chemical, paint & pigment industries, aerospace 

applications due to their lightness in weight and processability. Major research efforts 

have been made for improving their functionalities by addition or deposition of 

alloying elements such as Ni and by controlling the structure. However, it is difficult 

to fabricate these alloy powders by traditional metallurgical process and it is necessary 

to evolve new methods. Core-shell structured particles are attracting considerable 

attention as a consequence of their potential application in different areas of science 

and technology. Functionalizing the Al core with suitable shell materials indeed opens 

the door to specific physical, chemical and optical performances of Al. However, due 

to the oxide layer present on Al surface, it is difficult to plate Al with any metal or 

metallic base surface coating by post wet deposition techniques. Thus, we fabricated 

Al-Ni core-shell structured powders using electroless Ni plating. The pre-treatment 

was conducted for the formation of Ni shell as well as removal of the oxide layer. 

The formation of Ni shell on Al core powder was confirmed by SEM, XRD and VSM 

results.

SM01 

Breakdown of barkhausen critical scaling behavior with increasing 

domain wall pinning in fe thin films 

Hun-sung Lee 1 , Kwang-su Ryu 2 , Chun-yeol You 3 , Kun-rok Jeon 1 , Stuart S. P. Parkin 2 

and Sung-chul Shin 1 * 

1 

Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, 

Korea 

2 

IBM Research Division, Almaden Research Center, San Jose, CA 95120, USA 

3 

Department of Physics, Inha University, Incheon 402-751, Korea 

We report a breakdown of Barkhausen critical scaling behavior in Fe films with 

increasing domain wall pinning by means of a Kerr microscope, capable of direct 

domain observation. From the the domain reversal patterns in the films, we find that the 

Barkhausen jump size generally decreases with increasing Fe thickness, showing the 

increased domain wall pinning density. Surprisingly, the power-law scaling behavior of 

Barkhausen jump size distribution gradually disappears as pinning of domain walls in 

the Fe layer increases. This is due to the fact that magnetization reversal mechanism is 

changed from a random Barkhausen avalanche dominant mode to thermally activated 

domain wall creep dominant mode. 

SM02 

Enhanced critical fields in MnSi thin films 

Dirk Menzel*, Josefin Engelke, Tommy Reimann and Stefan Suellow 

Institute for Condensed Matter Physics, Technische Universitaet Braunschweig, 

Germany 

The magnetic properties of the cubic helimagnet MnSi are governed by the 

Dzyaloshinskii- Moriya interaction which in the bulk stabilizes a helical ground state 

below 29 K with a spin-helix wavelength of 18 nm and a propagation vector along 

the [111] direction. Recently, MnSi has attracted a lot of attention after a skyrmion 

lattice had been discovered in the so called A-phase. We have prepared thin MnSi 

films on Si(111) substrate by alloying a single Mn layer into the substrate as well as by 

codeposition of Mn and Si. RHEED analysis in combination with TEM investigation 

reveals that codeposition leads to smooth films whereas the alloying process generates 

rather three dimensional MnSi islands. In comparison to bulk material, the films show 

an enhanced magnetic ordering temperature of 45 K, which has been determined using 

SQUID magnetometry. Magnetization, resistivity, magnetoresistance, and Hall effect 

measurements have been performed on the films. They show that the critical fields 

describing the transition from the helical to a conical spin phase and from the conical 

phase to a parallel spin alignment are dependent on the film thickness and enhanced in 

comparison to single crystalline MnSi. 

SM03 

Magnetism and Cr 2O 3-Fe 2O 3 structure of CoFe/Cr-NOL surface 

Naoki Shimomura 1 *, Kazuya Sawada 2 , Tomohiro Nozaki 1 , Masaaki Doi 3 and Masashi 

Sahashi 1 

1 Department of Electronic Engineering, Graduate School of Engineering, Tohoku 


2 Toshiba Corporation, Japan 

3 Tohoku Gakuin University, Japan 

Magnetoelectric (ME) effect has been investigated for realizing electric controlled spintronic 

device, such as MERAM. Cr 2O 3 is the most promising material for the application due to high 

Neel temperature (TN : ~307K). Switching exchange bias field by applying electric field using 

bulk Cr 2O 3 (0.6mm) has been reported [1]. Recently, we have observed high blocking temperature 

(TB : ~250K) of CoFe/Cr-NOL (Nano-Oxide-Layer) containing Cr 2O 3 and Fe 2O 3 (TN ~ 950K) 

in its surface, in spite of the ultrathin thickness (less than 1nm). The NOL is prepared by Natural 

Oxidation (N.O.) of CoFe and ultrathin (1ML) Cr layer [2]. To clarify the reason of high TB 

of the NOL is important for achieving thin Cr 2O 3 film that shows ME effect higher than room 

temperature. In this study, we have investigated the structure and magnetic property of CoFe/Cr- 

NOL by varying constitution condition, such as deposition system and N.O. intensity. It was found 

that mixing of Cr into CoFe layer before N.O. and high N.O. intensity cause the formation of 

Cr 2O 3-Fe 2O 3 solid solution in NOL surface, which lower the TB. It is indicated that the presence of 

not Cr 2O 3-Fe 2O 3 solid solution but the existence of both Cr 2O 3 and Fe 2O 3 is needed for high TB. 

[1] Xi He, Yi Wang, Ning Wu, Anthony N. Caruso, Elio Vescovo, Kirill D. Belashchenko Peter A. Dowben, and Christian Binek, 

Nature Mater. 9, 579 (2010). [2] K. Sawada, N. Shimomura, M. Doi, and M. Sahashi, J. Appl. Phys 107, 09D713 (2010). 

SM04 

SM05 

SM06 


Magnetic phase diagram for non-epitaxial Cr/Gd/Cr-multilayers 

Andres Rosales Rivera 1 *, Juan Fernando Jaramillo 1 , Nicolas Antonio Salazar 1 , Olatz 

Idigoras 2 and Andreas Berger 2 

1 Laboratorio de Magnetismo y Materiales Avanzados, Universidad Nacional de 

Colombia, Sede Manizales, Colombia, Colombia 

2 CIC nanoGUNE Consolider, Tolosa Hiribidea 76, E-20018 Donostia-San Sebastian, 

Spain 

In this work, the low-temperature phase and critical behavior at high temperature of 

inhomogeneous gadolinium-chromium samples were investigated using DC magnetization 

measurements. The samples were prepared as Cr(50nm)/Gd(100nm)/Cr(50nm) multilayers 

grown onto Si(110) single crystal substrates by means of sputter deposition. The samples’ 

inhomogeneity was controlled by annealing at different temperatures Tan = 200, 400, and 

500°C during 10 minutes, and their magnetization was measured using zero field cooling (ZFC) 

and field cooling (FC) procedures at several applied fields. In the vicinity of room temperature, 

the magnetic behavior of the samples is compatible with a ferromagnetic ground state, 

which undergoes a rounded ferromagnetic (F)-paramagnetic (P) phase transition at a critical 

temperature, Tc. At temperatures below Tc, however, differences between the magnetization 

measured in the zero field cooling (Mzfc) and field cooling (Mfc) procedures are observed. 

Mfc decreases with increasing temperature. Mzfc increases with increasing temperature and, 

in addition to the F-P phase transition at Tc, shows a peak at a certain temperature Tg < Tc. It 

was also found that Mzfc is time dependent at low field and irreversible below an irreversible 

temperature Ti(H). A (H,T) phase diagram that contains Tc, Ti(H) and Tg(H) is presented for 

each of the samples. 

Revealing the volume magnetic anisotropy of Fe films epitaxied on 

GaAs(001) surface 

G. Chen 1 , J. Zhu 1 , J. Li 2 and Yizheng Wu 3 

1 physics department, Fudan university, China 

2 Physics department, Fudan university, China 

3 phyiscs department, Fudan university, China 

Fe film grown on GaAs(001) is a model system for studying the spin injection from 

a ferromagnetic layer into the semiconductor substrate. The Fe/GaAs(001) system 

exhibits a remarkable in-plane uniaxial magnetic anisotropy (UMA) with an easy 

axis (EA) parallel to the GaAs[110] direction, and such UMA is usually believed 

to originate entirely from the Fe/GaAs interface. In this contribution, we will show 

our quantitative studies on the thickness dependent magnetic anisotropy in Au/Fe/ 

GaAs(001) system using the magneto-optic Kerr effect with a rotating magnetic field. 

Through a clear 1/dFe relation of the UMA, we found a UMA component with the EA 

parallel to the GaAs direction which originates from the volume contribution. Such 

volume UMA is sensitive to the growth temperature and also strongly correlate with 

the interface anisotropy. We can conclude that both the volume anisotropy and the 

interfacial anisotropy are related to the ordered atomic structure at Fe/GaAs interface. 

Our results may introduce a new aspect for further understanding the origin of UMA in 

Fe/GaAs(001) system. 

1) G. Chen, J. Zhu, J. Li, F. Z. Liu, and Y. Z. Wu, Appl. Phys. Lett. 98, 132505(2011) 

Structures and magnetic properties of ultrathin Ni/Cu(100) in 

hydrochloric acid 

Jyh-shen Tsay*, Chun-liang Lin, An-wei Wu, Ying-chieh Wang and Yu-chieh Tseng 

National Taiwan Normal University, Taiwan 

Microstructure and magnetic properties of ultrathin Ni/Cu(100) prepared by way of 

electrochemical approaches are investigated. In a pure supporting electrolyte, the STM 

image of the chloride covered Cu(100) surfaces show the formation of 90-degree step 

edges of the terraces as a result of the electrochemical annealing [1]. After adding 

NiCl 2, the hydrogen evolution reaction is advanced to a more positive potential. Nickel 

atoms attach onto the steps and the surface shows single atomic steps corresponding to 

a layer-by-layer growth. As the coverage of Ni increases, large amount of clusters form 

on the surface. The adsorption of chloride anions occurs on the top of the films [2]. For 

thin Ni layers, no magnetic hystsresis is observed due to the lowered Curie temperature 

for ultrathin overlayers. As the Ni coverage increases, hystsresis loop is observed with 

in-plane anisotropy of the films. For thicker films spin reorientation transition occurs 

that may be due to the strain relaxation in the Ni overlayer. The high squareness of the 

magnetic hysteresis loops confirms the smooth interfaces of the Ni films. 

[1] S.L. Tsay, et al, Phys. Chem. Chem. Phys. 12, 14950 (2010); [2] P.Y. Yen, et al, J. Phys. Chem. C 

115 (2011) 23802. 


Poster Friday

Poster Friday 


SM07 

Improvement in structural and magnetic properties of laser ablated 

Ni-Zn Ferrite thin films 

Raghavender A T 1 *, Nguyen Hoa Hong 1 , Ekaterina Chikoidze 2 , Yves Dumont 2 and 

Kurisu Makio 3 


2 Laboratoire GeMAC, Universite de Versailles, France 

3 Department of Physics, Ehime University, Japan 

Zinc, as known as non-magnetic element, has been doped into Nickel-Ferrites under 

thin film form, with a hope to modify its structural and magnetic properties, in order to 

have the appropriate requirements for high frequency applications. Laser ablated Ni 1xZn 

xFe 2O 4 (0 ≤ x ≤1) thin films grown on R-cut Al 2O 3 (0001) substrates using pulsed 

laser deposition (PLD) technique are single phase with (l l l) orientation, and they 

are room temperature strongly ferromagnetic, while others’ similar works reported 

ferromagnetism only at low temperatures. Additionally, the higher HC value in our 

films compared to what others reported indicates that somehow we have found an 

appropriate way to make Ni-Zn ferrites become potential candidates for modern 

miniaturization of electronic devices. The zero field cooled ? field cooled (ZFC-FC) 

magnetization curves for all the films shows the blocking temperature (TB) suggesting 

a strong anisotropy. Research on Ni 1-xZn xFe 2O 4 (0 ≤ x ≤1) thin films would be very 

promising for device market. 

SM08 

A basic study of magnetic anisotropy strength control using FeSiB 

magnetostrictive thin film 

Jaewon Shin*, Sung Hoon Kim, Genki Kitazawa, Shuichiro Hashi and Kazushi Ishiyama 

Research Institute of Electrical Communication, Tohoku University, Japan 

The Magneto-Impedance (MI) sensors are used for various applications [1, 2]. A magnetic anisotropy 

controlling is important to improve sensitivity of MI sensor. Therefore, our research group proposed a new 

and simpler method to control magnetic anisotropy using inverse-magnetosriction and difference of thermal 

expansion coefficient in bimetal thin film[3]. To exploit the proposed method, investigation of a fabrication ratio 

between two layers (thickness and length) requires due to the sensitivity of proposed MI sensor is determined by 

changes in fabrication ratio. In this paper, we introduce the changes of magnetic anisotropy field (Hk) strength 

to develop high and adjustable sensitive MI sensor according to changes in geometrical properties of layers. The 

thin films were deposited by RF magnetron sputter. Fe 72Si 14B 14 and Molybdenum were used for the magnetic 

and conductive layer, respectively. The fabricated thin films annealed to release the local stress. We carried 

out magnetic domain observation by Kerr-microscope. Moreover, Hk value was obtained by VSM. Based 

on the experiments, we could confirm that Hk value was controlled by the geometrical properties because the 

geometrical properties can determine the generated stress in the magnetostrictive magnetic layer. This research 

provides the fabrication range and expectation of the sensitivity of MI sensor. 

[1]Y. Murayama, T. Ozawa, S. Yabukami, K. Ishiyama, and K.I. Arai, “High-Frequency Carrier-Type Magnetic Field Sensor with a Sub-pT 

Resolution Using a Magnetic Film and a Transmission Line,” J. Magn. Soc. Jpn, 31, 17-22, 2007. [2]T. Morikawa, Y. Nishibe, H. Yamadera, 

Y. Nonomura, M. Takeuchi, and Y. Taga, “Giant Magneto-Impedance Effect in Layered Thin Films,” IEEE Trans. Magn., 33, 4367-4372, 

1997. [3] Jaewon Shin, Sung Hoon Kim, Yasuaki Suwa, Shuichiro Hashi, Kazushi Ishiyama, “Control of In-plane Uniaxal Anisotropy of 

Fe72Si14B14 Magnetostrictive Thin Film Using a Thermal Expansion Coefficient,” J. Appl. Phys (will be published in April) 

SM09 

Magnetic properties of co thin films on polyethylene naphthalate 

organic substrates 

Hideo Kaiju*, Taro Abe, Kenji Kondo and Akira Ishibashi 

Research Institute for Electronic Science, Hokkaido Univerisity, Japan 

Recently we have proposed spin quantum cross (SQC) devices, in which molecules 

are sandwiched between two edges of magnetic thin films deposited on organic 

substrates with their edges crossed. According to our recent calculation, SQC devices 

exhibit large magnetoresistance effect at room temperature. In this study, towards the 

fabrication of SQC devices, we have investigated magnetic properties and surface 

morphologies of Co thin films on polyethylene naphthalate (PEN) organic substrates. 

Co thin films were thermally evaporated on PEN substrates under a magnetic field in a 

high vacuum chamber. The magnetization curves were measured by focused magnetooptic 

Kerr effect techniques at room temperature. The surface morphologies were 

analyzed by atomic force microscope. As a result, the surface roughness decreases 

from 1.3 to 0.55 nm with increasing the Co thickness up to 55 nm, where a two-step 

smoothing phenomenon can be seen. As for magnetic properties, the coercive force 

and the squareness of the hysteresis loop show the maximum values at a Co thickness 

of 5.3 nm. This peak is due to the rotation of the uniaxial magnetic anisotropy formed 

from both the induced magnetic anisotropy and the shape magnetic anisotropy affected 

by the surface morphologies of Co/PEN and PEN substrates. 


SM10 

Effects of dimensionality on magnetization of Ho and Sm-doped 

BiFeO 3 thin films 

Tae-young Kim 1 *, Anupati Telugu Raghavender 2 , Sugawara Takashi 3 , Makio Kurisu 3 and 

Nguyen Hoa Hong 4 

1 Physics, Seoul National University, Korea 

2 Physics, Seoul National University, India 

3 Physics, Ehime university, Japan 

4 Physics, Seoul National University, France 

BiFeO3 is promising multiferroic material due to high ferroelectric (1100 K) and antiferromagnetic (650 

K) ordering temperatures. Reports of other groups have suggested that by reducing the dimensionality, the 

spiral magnetic ordering could be suppressed [1]. Thus, multiferroics in thin films and nanocrystalline forms 

could enhance the magnetic properties [2]. In BiFeO 3, if Bi is substituted by a small amount of divalent or 

trivalent metal ions, or Fe is substituted by transition metal ion, a significant enhancement in magnetization 

can be achieved. We have prepared the nanocrystalline RE-BiFeO 3 (RE = Sm and Ho) by using sol-gel 

method to be target materials for thin films fabrication. RE-BiFeO 3 films were grown on LaAlO 3 substrates 

using pulsed laser deposition technique. All the films show a single phase of rhombohedral structure with 

space group R3c. Significant changes in the structural properties were observed as the thickness of the films 

increases. The magnetization observed in the case of Ho is much higher than those reported in literature 

and also Sm-doping shows better magnetization values. The magnetization increases as the film becomes 

thinner. This is a strong evidence for the origin of surface magnetism that exist in the films. 

[1] P. Thakuria and P. A. Joy, J. Appl. Phys. 97 (2010) 162504. [2] J. Wang, J. B. Neaton, H. Zheng, V. Nagarajan, S. B. Ogale, B. Liu, D. Viehland, V. 

Vaithyanathan, D. G. Schlom, U. V. Waghmare, N. A. Splandin, K. M. Rabe, M. Mutting and R. Ramesh, Science, 299 (2003) 1717 . 

SM11 

Substrate-dependent electronic anisotropy of epitaxial multiferroic 

DyMnO 3 and Dy 0.8Ca 0.2MnO 3thin films 

Kueih-tzu Lu, S. C. Haw, T. L. Chou, J. M. Lee, S. A. Chen and J. M. Chen 


We investigated the substrate-dependent electronic structure and anisotropic bonding 

of the Mn 3d states in DyMnO 3 and Dy 0.8Ca 0.2MnO 3 thin films on SrTiO 3(001) and 

LaAlO 3(110) substrates using polarization-dependent x-ray absorption spectroscopy 

(XAS) at O K-, Mn L- and Mn K-edges for three polarizations, E || a, E || b and 

E || c. Polarization-dependent x-ray absorption spectra at O K-, Mn L23- and Mn 

K-edges of orthorhombic DyMnO 3/LaAlO 3(110) thin films show a strong polarization 

dependence, whereas orthorhombic DyMnO 3 /SrTiO 3(001) thin films show nearly 

isotropic spectral structure. The main peak in polarized Mn L2,3-edge XAS spectra 

of DyMnO 3/LaAlO 3(110) thin films for the E || b polarization lies at a lower energy 

than for polarizations E || a and E || c. This indicates a great anisotropy in Mn 3d-O 

2p hybridization, reflecting an orbital ordering and a highly anisotropic coplanar 

Mn-O bonding in DyMnO 3/LaAlO 3(110) thin films. Orbital ordering of eg-orbital 

and the highly anisotropic in-plane Mn-O bonding is an indispensable factor to the 

formation of complicated incommensurate modulated magnetic structures observed 

in orthorhombic DyMnO 3. The present results provide important implications for the 

microscopic understanding of the multiferroic DyMnO 3. 

SM12 

Enhanced magnetization by substitution of Zn 2+ in Fe 3O 4 films 

Chang-yup Park 1 , Jong-hyun Song 2 , Chun-yeol You 3 and Sung-chul Shin 4 * 

1 Department of Physics and Center for Nanospinics of Spintronic Materials, Korea 

Advanced Institute of Science and Technology, Daejeon 305-701, Korea 

2 Department of Physics, Chungnam National University, Daejeon 305-764, Korea 


4 Department of Physics and Center for Nanospinics of Spintronic Materials, KAIST, 

Daejeon, Department of Emerging Materials Science, DGIST, Daegu, Korea 

Fe 3O 4 is one of the key materials as efficient spin injector for spintronic device. Thereby 

considerable researches have been carried out to obtain high magneto resistance ratio 

(MR), however no report show enough MR because of interface concerned problems 

and uncertainty of half metallic identity itself. Hence we choose Fe 3O 4 to investigate 

its nature and enhancement of magnetic and electric properties by substitution of Zn 2+ 

ion. Firstly we carried out magnetization hysteresis loop measurement by means of 

alternating gradient magnetometer. To find out a role of Zn substitution, we fabricated 

Fe 1.8Zn 1.2O 4 film and the saturation magnetization strikingly enhanced to 283 emu/cc 

from 79 emu/cc of the epitaxial Fe 3O 4 film. We believe that the 3.6 times enhancement 

is ascribed to the substitution of Zn 2+ ion instead of Fe ion at tetrahedral A site which 

spin is antiparallel to that of Fe ion at octahedral B site in inverse spinel structure of 

Fe 3O 4.

SM13 

Growth temperature dependence of crystal orientation and magnetic 

properties of CoMn2O4 thin films 

Taeyoung Koo 1 , Jaeyoung Kim 1 , Sunhee Kang 2 , Illwon Kim 2 , Yoonhee Jeong 3 , Myunghwa 

Jung 4 and Jonghyun Song 5 * 

1 

Pohang Accelerator Laboratory, Korea 

2 

Physics, Ulsan University, Korea 

3 

Physics, Pohang University of Science and Technology, Korea 

4 

Physics, Sogang University, Korea 

5 

Physics, Chungnam National University, Korea 

Co xMn 3-xO 4(0≤x≤3), which crystallize in the spinel structure, are strong candidates of multiferoics which can be 

used in various technical applications due to their thermal, electrical and magnetic properties. In the present work, 

we report on the growth of epitaxial CoMn 2O 4 thin films on Nb-doped SrTiO 3(001) substrate using Pulsed Laser 

Deposition and their magnetic properties. With all other growth parameters fixed, the growth temperature (Tg) was 

changed from 720oC to 920oC. The sample with Tg =720oC shows a strongly tensile strained epitaxial crystal 

structure with the orientation of (400). The M-H loops shows a ferrimagnetic behavior with the coercive field of 

~1.7 T. However, with increasing Tg up to 870oC, the tensile strained crystal domain becomes weaker whereas 

the domain of mixed orientations of relaxed (400) and (004) appear and has gained predominance. The M-H loops 

shows a weakened ferrimagnetism compared to the sample with Tg =720oC. With further increasing Tg to 920oC, 

interestingly, the crystal structure turns to be oriented (004) and the magnetic properties exhibit enhanced saturated 

magnetization with negligible coercive field. These observations indicate that the growth temperature plays a 

crucial role in determining the crystal structure and magnetic properties of CoMn 2O 4 thin film. 

[1]. V. Eladio, M. R. Rosa, L. M. V. Jose, and G. M. Oscar, Chem. Mater. 8, 1078 (1996). [2]. H. T. Zhang and X. H. Chen, Nanotechnology 17, 1384 (2006). 

SM14 

Structure and magnetic properties of Fe 3O 4 thin films on different 

substrates by Pulsed Laser Deposition 

Xuelian Huang, Yang Yang and Jun Ding* 

Materials Science and Engineering, National University of Singapore, Singapore 

Magnetite is an attractive magnetic oxide to be used in magneto-transport applications.[1]Many 

researchers have studied how to optimize the deposition condition for high quality magnetite thin 

films.[2]In this work,magnetite thin films were deposited on different substrates at temperatures 

varying from 100°C to 450°C,and their structure,magnetic and magneto-transport properties have 

been studied. XPS and Raman spectra reveal single phase of Fe 3O 4 on all the substrates.When film 

thickness is small and temperature is relatively high(>300°C),magnetite thin films on single crystal 

SiO 2,Si and amorphous glass exhibit strong (111) texture,no matter they have either a huge lattice 

mismatch or none matching with Fe 3O 4.The (111)texture can be formed at lower temperature(100°C) 

on (002)-ZnO due to the minimization of both surface and interfacial energy.The films on (0001)- 

Al 2O 3 show (111)-epitaxial structure in a large temperature range(100-450°C). The saturated 

magnetization for all the (111)oriented magnetite films are in the reported thin-film range.Magneto 

resistance up to 4% has been obtained.The out-of-plane MR exhibit quadratic behavior up to 6000 

Oe,whereas the in-plane MR is linear in this regime,which suggests the presence of anti-phase 

boundaries.[3]Large substrate-induced strain was found in the films grown on Al 2O 3 due to the lattice 

mismatch (8%),which significantly affected the magnetic anisotropy of the thin film. 

[1] H. Liu, E.Y. Jiang, H.L. Bai, R.K. Zheng, H.L. Wei, X.X. Zhang, Appl. Phys. Lett. 83 (2003) 3531. [2] S. Kale, S.M. Bhagat, S.E. Lofland, 

T. Scabarozi, S.B. Ogale, A. Orozco,S.R. Shinde, T. Venkatesan, B. Hannoyer, B. Mercey, W. Prellier, Phys.Rev. B 64 (2001) 205413. [3] W. 

Eerenstein, T. T. M. Palstra, S. S. Saxena, and T. Hibma Phys. Rev. L 88 (2002) 247204. 

SM15 

Influence of crystallographic orientation on the magnetic properties of 

NiFe, Ni, and Co epitaxial fcc films grown on single-crystal substrates 

Taiki Ohtani*, Tetsuroh Kawai, Mitsuru Ohtake and Masaaki Futamoto 

Chuo Univercity, Japan 

NiFe, Ni, and Co crystals with fcc structure are soft magnetic materials and have been used in magnetic 

thin film devices like magnetic heads and sensors. Magnetic property varies depending on the film texture 

[1,2]. In the present study, Ni 80Fe 20 (at. %), Ni, and Co films with fcc (100) and (111) orientations were 

prepared by hetero-epitaxial growth on single-crystal substrates of GaAs(100) and Al 2O 3(0001). The 

magnetic anisotropy, the magnetization structure, and the magnetostriction were investigated by employing 

RHEED, XRD, Bitter, and magnetostriction measurements. NiFe, Ni, and Co films of fcc(100) orientation 

showed four-fold symmetries in-plane magnetic anisotropy. The easy magnetization axes were parallel to 

[011] and [01-1] directions. 90° magnetic domain walls were observed for the epitaxial films. The in-plane 

magnetization properties were reflecting the magnetocrystalline anisotropies of respective bulk fcc crystals. 

On the contrary, the in-plane magnetization properties were isotropic for NiFe, Ni, and Co films with 

fcc(111) orientation. In magnetostriction measurement, the magnetostriction behavior of epitaxial magnetic 

thin film depended delicately on the magnetic domain structure and the domain wall motion under an 

influence of magnetic field. At the conference, the inter-relationships of magnetic anisotropy, magnetization 

structure, and magnetostriction will be discussed for these epitaxial thin films. 

[1] Y. Nukaga, M. Ohtake, M. Futamoto, F. Kirino, N. Fujita, N. Inaba.: IEEE Trans. Magn., vol. 45, pp. 

2519-2522, 2009. [2] M. Ohtake, T. Tanaka, K. Matsubara, F. Kirino, M. Futamoto.: J. Phys.: Conf. Ser., vol. 

303, pp. 012015_1-6, 2011. 

SM16 

SM17 

SM18 


Magnetic coupling in manganite-based thin film heterostructures 

studied by Electron Holography 

Luis Alfredo Rodriguez 1 , Lorena Marin 2 , Cesar Magen 3 *, Irene Lucas 4 , Pedro Antonio Algarabel 4 , 

Luis Morellon 2 , Jose Maria De Teresa 4 and Manuel Ricardo Ibarra 1 

1 LMA-INA, Universidad de Zaragoza, 50018, Zaragoza, Spain 

2 INA, Universidad de Zaragoza, 50018, Zaragoza, Spain 

3 LMA-INA and ARAID, Universidad de Zaragoza, 50018, Zaragoza, Spain 

4 ICMA, Universidad de Zaragoza-CSIC, 50009, Zaragoza, Spain 

Advances in nanofabrication of magnetic nanomaterials leads to search for new tools to measure physical 

properties at the nanoscale, such as magnetization. Accurate characterization of the magnetization states in 

nanostructures is of the utmost importance in the development new devices such as magnetic tunnel junctions 

(MTJs) [1]. Transmission electron microscopy (TEM) techniques such as Electron Holography (EH) allows the 

quantitative imaging of the magnetization states of ferromagnetic materials with unprecedented spatial resolution 

at the nanometer level [2]. Furthermore, EH can be combined with the in situ variation of external parameters such 

as magnetic and electric fields, temperature, etc. In particular, we use a TEM cryo-holder to image magnetization 

states of ferromagnets with low TC (down to 100 K) while varying in situ the magnetic field applied by the 

objective lens of the TEM. In this work, we present the EH study of the magnetization switching of La-Sr and La- 

Ca manganite thin films (TC = 180 and 300 K, respectively) and manganite-based MTJs [3]. The (de)coupling of 

magnetic electrodes in MTJs is analyzed by performing hysteresis loops at 100 K to determine the switching fields 

from the direct observation of the magnetization orientation of the electrodes upon magnetic field [4]. 

[1] S Yuasa et al., Nat. Mat. 3 (12): 868-871 (2004); S. S. P. Parkin et al. Nat. Mat. 3 (12): 862-867 (2004). [2] R. E. Dunin-Borkowski, M. R. McCartney, D. J. Smith, Electron 

Holography of Nanostructured Materials. In Encyclopaedia of Nanoscience and Nanotechnology; Nalwa, H. S., Ed.; American Scientific Publishers: Stevenson Ranch, 

California, 2004; Vol. 3, pp 41-100. [3] M. Bowen et al., Appl. Phys. Lett. 82, 233 (2003). [4] E. Javon, A. Masseboeuf, C. Gatel and E. Snoeck, J. Appl. Phys. 107, 09D310 (2010) 

Properties of hybrid superconductor/ferromagnet (SC/FM) multilayers 

U. D. Chacon Hernandez 1 , Y. T. Xing 2 , William E. Alayo 1 , Magda B. Fontes 1 , Jorge L. Gonzalez 3 , Liying 

Liu 4 , G. Solorzano 4 and E. Baggio-saitovitch 1 

1 Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil, Brazil 

2 Universidade Federal Fluminense Niteroi, Brazil, Brazil 

3 Universidade Federal do Espirito Santo, Vitoria, Brazil, Brazil 

4 PUC-Rio de Janeiro, Brazil 

Recent research on systems that contain two types of materials (hybrid systems) shows that new phenomena can 

be observed. One of such hybrid systems is superconductor/ferromagnet (SC/FM) nanocomposites, which shows 

coexistence of superconductivity and ferromagnetism with unusual properties. We use niobium (Nb) as the 

superconducting layers with fixed thickness (50 nm) and cobalt or permalloy (NiFe) as the ferromagnetic layers 

with different thickness (5, 10 and 20 nm). The films prepared by magnetron sputtering deposition technique, 

have been characterized by x-rays diffraction and in some cases the cross section at interface were studied by 

TEM. Characterization of SC and FM transitions was done by resistivity and magnetization measurements. The 

properties of superconductor changed at the SC/metal interface because of the proximity effect, for example, 

decrease of Tc. Moreover, the magnetic layers between superconducting layers will give have more influence on 

the superconductivity due to its stray field. Our results show that when the external magnetic field is close to the 

upper critical field Hc2, the SC/FM multilayers can have a vortex solid to a liquid phase transition. We believe 

that the stray field of the magnetic layers contributes to the melting of the vortex solid state. 

[1] A. I. Buzdin. Rev. Mod. Phys., 77(3):935, 2005. [2] Y. T. Xing, H. Micklitz, T. G. Rappoport, M. V. Milo sevi c, I. G. Sol orzano-Naranjo, and E. Baggio- 

Saitovitch. Phys. Rev. B, 78(22):224524, 2008. [3] Y. T. Xing, H. Micklitz, W. T. Herrera, T. G. Rappoport, and E. Baggio-Saitovitch. The European Physical Journal 

B - Condensed Matter and Complex Systems, 76:353{357, 2010. [4] E. A. Demler, G. B. Arnold, and M. R. Beasley. Phys. Rev. B, 55(22):15174{15182, Jun 1997. [5] 

I. A. Garifullin. Journal of Magnetism and Magnetic Materials, 240(1-3):571 - 576, 2002. 4th <strong>International</strong> Symposium on Metallic Multilayers. 

Effect of substrate on the anisotropic magnetotransport in 

Sm 0.45Nd 0.10Sr 0.45MnO 3 thin films 

Pawan Kumar 1 , M. K. Srivastava 1 , G. D. Verma 2 , R. K. Dwivedi 3 and H. K Singh 1 

1 Quantum Phenomena and Applications, National Physical Laboratory (CSIR), India 

2 Department of Physics, IIT Roorkee, India 

3 Department of Physics & Materials Science and Engineering, Jaypee Institute of 

Information Technology (Deemed University), India 

Sm 0.45Nd 0.10Sr 0.45MnO 3 thin films on single crystal LAO and STO substrates were 

prepared by ultrasonic nebulized spray pyrolysis. The PM-FM transition was observed 

at TC - 153 K and 150 K in film on LAO and STO, respectively. The magnetic moment 

was found to be smaller in film on STO and it showed stronger bifurcation between the 

ZFC-FC magnetization. The isothermal M-H loops measured with H applied parallel 

and normal to the film surface showed that the easy axis was in the film plane, while 

the hard axis was along the normal. The dominance of the shape anisotropy explains 

the in-plane magnetic easy axis. Large low field magnetoresistance (MR) is observed in 

both films. The occurrence of significantly smaller peak anisotropic magnetoresistance 

(AMR) at a temperature lower than the TIM and the broadening of the AMR-T curve 

suggest that films on STO have higher fraction of the AFM-COI phase. The difference 

in the magnetotransport anisotropy in the set of films has been explained in terms of 

substrate induced strain, e.g., STO provides tensile strain, which is known to favor the 

AFM-SE and CO-OO phases. 


Poster Friday

Poster Friday 


SM19 

Magnetism of multilayer (CoNiPsoft/CoPhard)n films 

Gennady Patrin 1 , Marina Pal'chik 2 , Dmitry Balaev 2 , Semion Kiparisov 2 and 

Konstantin Patrin 2 


2 Institute of Physics of Siberian Branch of Russian Academy of Sciences, Russia 

The (CoNiPsoft/CoPhard)n films were prepared by chemical deposition method. 

The content of phosphorus was 8 % at. in each layer. In hard magnetic layer the CoP 

was in hexagonal state and in soft magnetic layer the CoNiP was in amorphous state. 

The thickness of each layer was t = 4 nm. Magnetic measurements were made with 

vibrating-coil magnetometer in temperature range T = 77 ÷ 400 K and in magnetic 

fields H < 10 kOe. We investigated changes of magnetic parameters in dependence 

on number of layers in multilayer structure. In our experiments number of layer pairs 

was n ≤ 15. Earlier [1] it was established that the coercive force (HC) of CoP layers 

depends on layer thickness and HC rises when layer thickness increases. In given case 

at nitrogenous temperatures the coercive forces of soft magnetic and hard magnetic 

layers were ~ 20 Oe and ~ 1000 Oe, respectively. The combination of these layers into 

structure leads to substantial change of magnetic behavior of structure in whole [2]. It 

attracts attention that the soft magnetic layer determines the behavior of magnetization 

of film structure decreasing the coercive force of system. 

[1] A.V. Chzhan, G.S. Patrin, et al., Phys. Met. Metalloved., 109 (2010) 1. [2] A.V. Chzhan, G.S. 

Patrin, et al., Bull. Russ. Acad. Sci. Phys., 76, (2012) 180 

SM20 

Significant change in the antiferromagnetic-to-ferromagnetic phase 

transition temperature of epitaxial FeRh thin films by Ga substitution 

Ippei Suzuki 1 *, Mitsuru Itoh 1 , Tetsuya Sato 2 and Tomoyasu Taniyama 1 


2 Department of Applied Physics and Physico-Informatics, Keio University, Japan 

B 2 ordered FeRh alloys exhibit fascinating magnetic properties such as the firstorder 

magnetic phase transition from the antiferromagnetic (AF) to ferromagnetic 

(FM) states at around 400 K. For a step toward the incorporation of this material into 

devices, the control of the transition temperature in a thin film form is one of the most 

critical issues. In this study, we find that Ga substitution in FeRh efficiently reduces 

the transition temperature down to room temperature, making the use of this material 

a reality. A 30-nm-thick FeRh thin film and a Ga-substituted FeRh(Ga-FeRh) were 

epitaxially grown on MgO(001) substrates by molecular beam epitaxy. The temperature 

dependent magnetization of the epitaxial films clearly demonstrates the reduction of 

the transition temperature down to room temperature. The change in the transition 

temperature can be understood in terms of a possible change in the electronic states 

near the Fermi level due to the lattice expansion, leading to a more stable FM state in 

Ga-FeRh. In fact, the out-of-plane lattice parameters calculated from the XRD patterns 

are found to expand from 2.990 to 3.003 Å by the Ga substitution. Work supported in 

part by Industrial Technology Research Grant Program in 2009 from NEDO, Japan. 

SN01 

Structural and magnetic properties of Sm 2Co 17 nanoflakes prepared by 

surfactant-assisted ball milling 

Ming Yue, Rui Pan, Xiaofei Yin, Dongtao Zhang, Weiqiang Liu and Jiuxing Zhang 

College of Materials Science and Engineering, Beijing University of Technology, 

China 

Microstructure, crystal structure and magnetic properties were studied for Sm 2Co 17 

nanoflakes prepared by surfactant-assisted high energy ball milling with heptane and 

oleic acid as the milling medium. Effect of ball milling time on the crystallographic 

alignment evolution and coercivity of the nanoflakes were systematically investigated. 

Microstructure observation shows that the Sm 2Co 17 nanoflakes have an average 

thickness of less than 100 nanometers with an aspect ratio as high as 100. For the 2 

hours ball milled nanoflakes, the intensity ratio between (004) and (302) reflection 

peaks, which indicates the degree of c-axis crystal texture of the Sm 2Co 17 phase, 

reaches the maximum value among all the samples, revealing that the strongest c-axis 

crystal texture was obtained in this nanoflakes. As the ball milling time increases, the 

intensity ratio drops gradually indicating that the long time milling process undermines 

the c-axis crystallographic alignment of Sm 2Co 17 phase in the nanoflakes. On the other 

hand, it is found that as the ball milling time increases from 2h to 10h, the coercivity 

of the nanoflakes firstly increases, peaks at 2.8kOe for 8h, and then decreases again. 

Further investigation indicates that the microstructure evolution plays an important role 

in the coercivity variance of the Sm 2Co 17 nanoflakes. 


SN02 

Rotor structure optimization of interior permanent magnet by using 

response surface method 

Jung-ho Han, Ik-sang Jang, Mi-jung Kim, Ki-doek Lee and Ju Lee* 

Electrical Engineering, Hanyang University, Korea 

Due to limited energy sources and environmental pollution issues recently, the needs 

of high efficiency electricity equipments are steadily increasing. Among them, an IPM 

is being developed for the application of eco-friendly vehicle. An Interior Permanent 

Magnet has a structure of inserted permanent magnet in the inner rotor. These motor 

requires high torque and low torque ripple. It was designed with 8 pole 36 slot of 

stator and rotor, alternating N pole and S pole of permanent magnet and triangle 

type permanent magnet. In order to find the optimized condition, Central Composite 

Designs method and Box-Behnken method of Response Surface Method were used for 

finding design variable and minimizing variation of design variable. Comparing two 

Surface Reaction Methods, electromagnetic finite element method analysis based on 

inserting variation of design variables, torque, torque ripple, harmonics were obtained 

and optimized final value was obtained by safety factor through mechanical stiffness 

analysis. 

[1] Ian P. Brown, Robert D. Lorenz, “Response Surface Methodlogies for the Design of Induction Machine Self-Sensing Rotor 

Position Saliencies”, Proceeding of <strong>International</strong> <strong>Conference</strong> on Electrical Machines and Systems, p1354-1359, 2007 [2] I. P. 

Brown and R. D. Lorenz, 'Response surface methodologies for the design of induction machine self-sensing rotor position saliencies,' 

ICEMS, 2007. [3] K. Ide, I. Murokita, S. Mitsujiro, O. Motomichi, N. Yukio, J. I. Ha, and S. K. Sul, 'Finite element analysis of 

sensorless induction machine by high frequency injection,' Proc. of the IPEC, Tokyo, Japan, 2000. 

SN03 

Magnetization reversal behavior of FePt/MgO/FePt thin film 

Hiroki Iwama, Shinji Matsumoto, Katsuya Sugawara, Kotaro Sato, Masaaki Doi and 

Toshiyuki Shima 

Tohoku Gakuin University, Japan 

L10 ordered FePt alloy has attracted much attention, since they are believed to be good 

candidates for future magnetic devises. It is also thought to overcome the problem 

of thermal fluctuation in nano-meters scale. A lot of studies such as thin films and 

self-assembled nano particles have been investigated [1-3]. However, the magnetic 

properties of the multilayered FePt alloy have not been completely clarified. In order 

to understand the magnetization reversal, FePt/MgO/FePt trilayer films have been 

fabricated and detailed magnetic domain observation have been investigated. FePt 

bottom layer was co-deposited with Fe and Pt on Au buffer layer by using an UHVcompatible 

magnetron sputtering system. Then, the intermediate MgO layer and 

FePt top layer were deposited. Finally, the samples were annealed at Ta of 600 ºC. 

The magnetic domain structure was observed by magnetic force microscope (MFM) 

in applied fields up to ±6 kOe. Remarkable steps of the magnetization in the second 

quadrant were observed for all the samples. This is thought to arise from the difference 

in the chemical ordering of top and bottom FePt layers. Independent magnetization 

reversal of the top and bottom FePt layers was clearly observed at the FePt/MgO/FePt 

circular dots by the MFM measurements. 

[1] T. Shima et al., Appl. Phys. Lett. 99. 033516 (2006). [2] T. Shima et al., Appl. Phys. Lett. 81. 

1050 (2002). [3] S. Matsumoto et al., J. Phys.: Conf. Ser. 266. 012038 (2011). 

SN04 

Efficiency and torque density improvement of interor permanant 

magnet synchronous motor 

Mi Jung Kim, Ki Doek Lee, Jae-jun Lee, Jeong-ho Han, Tae-chul Jeong, Woong-chan 

Chae and Ju Lee* 

Hanyang University, Korea 

The motor should be designed with a minimum of because motor weight has quite large 

portion in totality mass; because there is no generator as electrical vehicle, the high 

efficiency is demanded in order to increase the 1 charging distance. In this paper, the 

technique is presented for progression of the torque density and the efficiency through the 

relative electric loading and the shape of rotor magnet. In case of the established model, 

the required torque satisfied at the rated speed and maximum speed, however, the torque 

density is low. When the mass of occupied by the motor is going to be bulky, 1 charging 

distance is decrease due to the increase in the driving load. The current density was 

increased to boost the torque density. The motor size could be decreased owing to change 

the current density, but there is a weakness at efficiency. The copper loss is enlarging with 

the current density. To increasing both of them efficiency and power density, the relative 

magnetic loading also should increase according to increase the relative electric loading. 

To increase the relative magnetic loading, redesign the PM shape of rotor. 

[1] Yukio Honda, Tomokazu Nakamura, Toshiro Higaki, Yoji Takeda, 'Motor design consideratioin and test results of an 

interior permanent magnet synchronous motor for electric vehicles', IEEE Industry Applications Society, Annual Meeting, 

pp. 75~82, 1997 [2] Sung-Il Kim,etc., “Optimization for reduction of torque ripple in interior permanent magnet motor by 

using the taguchi method”, IEEE Trans. on magnetics, vol. 41, no.5, pp. 1796~1799, 2005

SN05 

An effective skew method for torque ripple reduction in surfacemounted 

permanent magnet motor 

Taewoo Kim and Junghwan Chang* 

Electrical Engineering, Dong-A University, Busan, 604-714, Korea, Korea 

This paper deals with an effective skew method for surface-mounted permanent 

magnet motor (SPMSM). Skew is a common method to reduce cogging torque and 

torque ripple as well, and it can be done by continuous way in small machines or multistepwise 

method in big machines [1-2]. Generally, these conventional ways assume that 

the magnetic flux density distributions are same in axial direction and the contribution 

of the rotor on the generated torque is also same in all axial direction. However, the 

air-gap flux density is not uniform in axial direction, and it is rapidly reduced at both 

ends of the motor. Especially, in the pancake type motor, the influence of end sides is 

significant. Thus, for skew to be effective, non-uniform air gap flux density distribution 

in axial direction should be considered. In this paper, one method for an effective skew 

is suggested by considering flux density distribution in axial direction, and the results 

will be confirmed by 3D finite element analysis. 

[1] R. Islam, I. Husain, A. Fardoun, and K. McLaughlin, 'Permanent Magnet Synchronous Motor 

Magnet Designs with Skewing for Torque Ripple and Cogging Torque Reduction,' IEEE Trans. Ind. 

Appl., vol.45, no.1, pp.152-160, 2009. [2] Y. Donmezer, L.T. Ergene, 'Skewing effect on interior type 

BLDC motors,' ICEM XIX <strong>International</strong> <strong>Conference</strong>, pp.1-5, 2010 

SN06 

Effect of carbon additive on the TbCu 7-type melt spun Sm(Co, M)7 

(M=Ti, Zr, Hf, V, Nb and Ge) ribbons 

C.c. Hsieh 1 , H.w. Chang 2 , C.w. Shih 1 , W.c. Chang 1 * and C.c. Shaw 3 

1 National Chung Cheng University, Taiwan 

2 Tunghai University, Taiwan 

3 Superrite Electronics Co. Ltd, Taiwan 

Recently, Sm-Co compounds with TbCu 7-type structure have received intensive 

attention due to their excellent intrinsic magnetic properties, which have potential 

to be used as the starting materials for making bonded magnets for above 150 oC 

applications. Our previous studies indicated that pure TbCu 7-type structure could 

be obtained easily in melt spun Sm(Co,M)7 (M=Ti, Zr, Hf, V, Nb and Ge) ribbons. 

Based on the purpose of developing Sm(Co,M)7 alloys with TbCu 7-type structure 

for practical usage, effect of carbon on the microstructure and magnetic properties 

of melt spun SmCo 7-xM xC0.1 (M=Ti, Zr, Hf, V, Nb and Ge; x=0-0.3) ribbons were 

studied. Based on the XRD and TEM analysis, a pure 1:7 phase could be kept for the 

ribbons with M= Nb, and Ge, but carbide phases, eg. TiC for M=Ti, ZrC for M=Zr, 

Sm 2C 3 for M=Hf, and SmCoC 2 for M=V, respectively, were found for other ribbons. 

Nevertheless, a slight C addition may effectively refine the microstructure and improve 

both the intrinsic coercvity and the magnetic energy product in all the studied ribbons. 

Among them, the SmCo 6.9V 0.1C 0.1 ribbons with σr=58.7 emu/g, iHc=13.5 kOe and (BH) 

max=9.3 MGOe, and SmCo 6.9Hf 0.1C 0.1 ribbons with σr=61.6 emu/g, iHc=11.8 kOe and 

(BH)max=10.3 MGOe are suitable for the bonded magnet applications. 

SN07 

Study of designed induction motor on cryogenic LNG pump system 

Jinsung Kim and Gwansoo Park* 

Pusan National University, Korea 

In this Paper, I designed LNGs main cargo pump's motor using LNGs ship. LNGs 

ship has made a high value product and won steady demand order in every year. 

However, in Korea, when we make a LNGs ship, we import the key products from 

other countries(It's almost 60% of order price). So, we need to develop original skill 

about key product. LNGs main cargo pump's motor is submerged, and induction 

motor type. In this paper, first of all, design the induction motor using constants at 

room temperature. And then, we re-design the motor considering an extremely low 

temperature. This motor's working operation temperature is -163°C. Because of that, it 

can make a special design. In other words, we don't need to think about heat loss as like 

as room temperature. In this reason, we consider about losses by current density and 

flux density. First, coil loss is generated a heat. So, it can be cooling the coil heat loss 

immediately. On the other hands, magnetic saturation has effect on characteristics of 

material (specially, B-H curve). So, we think about magnetic saturation, even it works 

at low temperature. 

L.Dlufiewicz, J. Kolowrotkierwicz, W. Szelag, M. Barancki, and R. Neumann, Electrical Motor 

for Liquid Gas Pump, SPEEDAM, pp.311-316 (2006). Shiyley R, Miller H, Development of a 

Submerged Winding Induction Generator for Cryogenic Application, Conf. of IEEE Symp. on 

Electrical Insulation, pp.243-246 (2000). Rush, S, Submerged Motor LNG Pumps in Send-out 

System Service, Pumps&System, pp.32-37, (2004). Stephen J. Chapman, Electric Machinery 

Fundamentals, pp.380-425, (2003). 

SN08 

SN09 

SN10 


Structural and magnetic properties of nanocrystalline BaFe 12O 19 

synthesized by microwave-hydrothermal method 

K Sadhana and K Praveena 

Materials Research Centre, Indian Institute of Science, Banglore-560012, India, India 

The nanocrystalline BaFe 12O 19 powders were prepared by Microwave-Hydrothermal 

(M-H) method at 200°C/45 min. The as synthesized powders were characterized by 

using X-ray diffraction (XRD). The present were densified at different temperatures i.e., 

750°C, 850°C, 900°C and 950°C for 1h using microwave sintering method. The phase 

formation and morphology studies were carried out using XRD and field emission 

scanning electron microscopy (FE-SEM). The average grain sizes of the sintered 

samples were found to be in the range of 185 to 490 nm. The magnetic properties such 

as saturation magnetization and coercive field of sintered samples were calculated 

based on magnetization curves. A possible relation between the magnetic hysteresis 

curves and the microstructure of the sintered samples was investigated. 

Research magnetic properties of Fe-O alloys with different texture 

degrees and ratios of phases using simulating 

Alexey Lileev*, Ivan Pelevin and Anna Starikova 

National University of Science and Technology 'MISIS', Russia 

The present article is concerned with investigation of magnetic properties of Fe-O 

alloys, simulating their magnetic behaviour and causation of the high-coercivity 

state of these alloys. Initial materials were powder so-called “Blue dust” and mixture 

of this powder with Fe powder with different rations of these phases. “Blue dust” 

is a powder of Fe 2O 3, it’s a natural Indian raw. Reserves of this material sufficient 

large, so a production material with high magnetic properties from it is an urgent 

problem. Initial samples were powdered in high-energy ball mill for different time 

periods. This treatment leads to phase transformation. The phase compositions were 

investigated by X-ray analysis. The impact of time of milling and initial composition 

on magnetic properties was explored. Milled nanocrystalline powders were subjected 

to a low-temperature crystallization annealing in magnetic field. It leaded to phase 

transformation. Powder was pressed into cubic shape samples. The dependence 

of magnetic properties on composition after annealing was also investigated. The 

computer simulating was used to understand which phase is cause og forming the highcoercitive 

state of material. Initial parameters were set so that result corresponds to 

experimental data. The parameter changing showed quite how each of them influence 

on magnetic properties. 

Study on FePt/Fe exchange coupling nanocomposite thin films 

Wenli Pei 

ATM, Northeastern University, China 

Granular FePt films with island microstructures have been deposited by DC magnetron 

sputtering. The FePt grain size and distance among FePt grains could be controlled by 

tuning sputtering condition. An iron layer was deposited on the controllable island FePt 

film to produce FePt/Fe nanocomposite thin film. The composite films show a hard/soft 

magnetic exchange coupling after annealing, because the FePt grains in the composite 

film became L10 structure with good hard magnetic properties after annealing. The 

exchange coupling could be modified by tuning granular FePt structure and thickness 

of Fe layer, which means it’s promising to produce FePt/Fe nanocomposite magnet 

with good magnetic properties by this method. 

1. Kneller E F, Hawig R. The exchange-spring magnet: a new material principl for permanent 

magnets. Magnetics [J], IEEE Transactions on Magnetics, 1991. 27(4): 3588- 3560. 2. Zhou J, 

Skomski R, Li X, et al. Permanent-magnet properties of thermally processed FePt and FePt-Fe 

multilayer films [J], IEEE Transactions on Magnetics, 2002, 38(5Part 1): 2802-2804. 


Poster Friday

Poster Friday 

SN11 


Effects of Sm content on thermal stability of sintered Sm2Co 17 magnets 

Minggang Zhu, Haibo Feng, Wei Li, Yikun Fang, Wenchen Zhang and Wei Pan 

China Iron & Steel Research Institute Group, China 

Investigations on environment stability of the Sm 2Co 17 type magnets have been one 

of hot pots on applications of Sm-Co based magnets. Effects of heavy rare-earth 

elements substitute Sm on temperature coefficient of remanence (?) of the magnets 

have been investigated systematically [1]. Sm 2Co 17 magnet with high coercivity has 

the best thermal stability among all permanent magnets [2]. The reversible temperature 

coefficient ? was zero in the (Sm 1-xGd x)(CoFeCuZr)z magnet when x=0.55[3]. In this 

paper, the dependence of Sm content on temperature coefficient of 2:17 type Sm-Co 

magnets at different temperature were investigated. As shown in Fig.1, the temperature 

coefficient increased with temperature when z value of the magnets is the same. While, 

the temperature coefficients of remanence firstly decreased and then increased with 

z value at the same temperature. When z=7.87, magnet with the best temperature 

stability, the highest coercivity and the lowest temperature coefficient of remanence 

were obtained. 

[1]Chen Christina, Gong Wei, Michael Walmer H. Journal Applied Physics, 2002, 91(10): 8483. 

[2]Li D, Misdrum H F, and Strnat K J. Journal Applied Physics, 1988, 63(8): 3984. [3]Liu Jinfang, 

Payal Vora and Michael Walmer. Journal of Iron Steel Research <strong>International</strong>, 2006, 13: 319. 

SN12 

Simulation of die-upsetting process of hot-deformed magnets 

Bin Lai*, Huijie Wang, Minggang Zhu and Wei Li 

Division of Functional Materials, Central Iron & Steel Research Institute, China 

A plastic deformation simulation was performed by using a three dimensional finite element 

method based deformation modeling software in order to clearly understand the die-upsetting 

process in detail. It was found by the plastic deformation simulation that the effective strains of 

Nd-Fe-B die-upset magnets reduced from the middle to the ends of magnetic specimens along 

the c-axis, or the press direction, so the crystallographic orientation deteriorated for the grains 

approached to both ends of die-upset magnets. The magnetic properties were improved with 

increase of effective strains of die-upset magnets.The remanence Br and maximum energy 

product (BH) m were high for the specimens, machined from the central region of magnets, 

because the microstructure of die-upset magnets was homogeneous and grains were aligned 

well in the central region of deformed magnets according to the simulation. Experimentally, 

the magnetic properties, X-ray diffraction patterns and microstructure of hot-deformed Nd- 

Fe-B magnets were studied. The magnetic properties were improved with decreased height of 

magnet specimens which were obtained by symmetrically removing both ends of die-upset 

magnets. The grain misalignment was as enhanced from the middle to both ends of die-upset 

magnets along c-axis.The microstructural characterization was verified by experiment. 

[1] Yutaka, Matsuura, J. Magn. Magn. Mater. 303 (2006) 344 [2] N. Yoshikawa, T. Iriyama, and H. Yamada. IEEE Trans. Magn., 35 (1999) 

3268 [3] T. Harada, M. Fujita, T. Kuji, Journal of Alloys and Compounds, 243 (1996) 139 [4] T. Saito, M. Fujita, T.kuji, et al., J. Appl. Phys., 

83 (1998) 6390 [5] Y. Yoshida, Y. Kasai, T. Watanabe, et al., J. Appl. Phys. 69 (1991) 5841 [6] D. N. Brown, B. Smith, B.M.Ma, et al., IEEE 

Trans. Magn., 40 (2004) 2895 [7] M. Leonowicz, D. Derewnicka, M. Wozniak, et al., 153/154 (2004) 860 

SN13 

Synthesis of high magnetic moment nanowires for encoding and 

decoding of barcode segments for multiplexing bio- applications 

Torati Sri Ramulu 1 , Reddy Venu 1 , Brajalal Sinha 1 , Xinghao Hu 1 , Sook Soo Yoon 2 and 

Cheol Gi Kim 1 * 

1 Material science and engineering, Chungnam national university, Korea 

2 Material science and engineering, Andong national university, Korea 

Abstract: Sequential template electrochemical synthesis of multisegment nanowires with 

magnetic and non-magnetic segments have been extremely significant for barcoding, 

multiplexing and biosensing applications [1,2]. Especially, Hard magnetic segment with high 

saturation magnetization and remenance materials are more convenient for multiplexing 

biological applications. In the present article we have synthesized three different types of 

magnetic nanowires ( CoNiP, CoPtP and CoFeP) for a magnetic segment of barcode nanowires 

by electrochemical deposition technique using a polycarbonate membrane with a diameter of 

50 nm. The length of the nanowires was found to be around 6 μm. We compared the magnetic 

properties of all the synthesized materials and found to be the CoPtP magnetic nanowires have 

higher saturation and remenence. In order to demonstrate the decoding of barcode nanowires 

using the magnetoresistance sensor in flow cytometry, we calculated the spatial distribution of 

the stray magnetic field produced by the barcode nanowire by means of finite element method 

(FEM) using the commercial Maxwell software. The CoPtP shows most higher spatial variation 

compared to the CoFeP and CoNiP, which means CoPrP is most advantageous composition for 

the hard magnetic segment. 

[1] K. B. Lee, S. Park, and C. A. Mirkin, 2004, Angew. Chem. Int. Ed., 43, 3048 [2] A. K. Salem, P. C. Searson And K. W. Leong, Nat.Mat., 2003, 2, 668. 


SN14 

A new mechanism of electromagnetic linear-actuator using a magnetic 

silicone rubber 

Takanori Fukushi, Sung Hoon Kim*, Shuichiro Hashi and Kazushi Ishiyama 

Research Institute of Electrical Communication, Tohoku University, Japan 

We propose a new mechanism of electromagnetic linear-actuator for biomedical applications such 

as an artificial muscle and medical micro-robots [1-3]. The proposed mechanism requires two 

armatures and magnetic rubber in the DC-solenoid. The proposed structure is series connection: 

armature_1, magnetic rubber, and armarture_2. Therefore, D.C magnetic field produces attractive 

force between the two armatures. At that time, the magnetic rubber causes increase of attractive 

force because the magnetic rubber was fabricated by iron powders with silicone elastormer (36 : 64 

wt %), as a cylindrical shape (diameter:12 mm and height: up to 8.9 mm). Its magnetic properties 

were measured by VSM; magnetization and coercive force are 50 emu/g and 40 Oe, respectively. 

We compared magnetic force between the two armatures with the magnetic rubber and with a nonmagnetic 

rubber in magnetic field of 600 Oe. We found the magnetic rubber made the attractive force 

1.7 times larger. This also means the use of magnetic rubber makes the low power consumption. The 

largest advantages of this magnetic rubber are the increase of attractive force, generation of reaction 

force, and the flexibility as soft elastmer, so it can be used for various biomedical applications. The 

details will be introduced in the conference. 

[1] B.Kim, M.G.Lee, Y.P.Lee, Y.Kim, and G.Lee, “An earthworm-like micro robot using shape memory alloy actuator,” Sens. Actuators A., 

125, 429-437, 2006. [2] H.Lu, J.Zhu, Z.Lin, and Y.Guo, “An inchworm mobile robot using electromagnetic linear actuator,” Mechatronics, 

1-10, 2009. [3] T.Niino, S.Egawa, H.Kimura, and T.Higuchi, “Electrostatic Artificial Muscle: Compact, High-Power Linear Actuators with 

Multiple-Layer Structures,” Proc. IEEE Micro Electro Mechanical Systems Workshop, 94, 130-135, 1994 

SN15 

Novel microcrystalline Co-Zr-B RE-free hard magnetic alloys 

Sofoklis Makridis and Evagelos Gkanas 

Department of Mechanical Engineering, University of Western Macedonia, Greece 

The investigation of rapidly solidified alloys is important both for the basic information 

it gives about the structural and compositional limits of magnetism and for the 

technical potential of new alloys. Co-based amorphous alloys have the advantage of 

relatively high saturation flux density and low magnetostriction. The glass formability 

and technical magnetic properties of rapidly solidified Co(rich)-Zr-B alloys were 

investigated in the composition range Co 82Zr xB 20-x. in order to determine the glass 

forming range and explore the magnetic characteristics as a function of composition 

and quenching rate. The alloys were found to be completely glassy for low x whereas 

all the other compositions studied were completely or partially crystalline. The typical 

glassy alloys showed good soft magnetic properties. The crystalline alloys with Zr 

content higher than 80 % in Boron were characterized by a coercive force in excess of 

4 kOe. Slow-cooled samples of the same composition showed coercivity in the order 

of 120 Oe. 

SO01 

First-principles study on the half-metallicity of full-Heusler alloy 

Co 2VGa (111) surface 

Hongpei Hong, Kailun Yao* and Guoying Gao 

physics, Huazhong university of science and technology, China 

A recent experimental study indicates that full-Heusler alloy Co 2VGa exhibits halfmetallic 

ferromagnetism and the magnetic moment measured at 5 K is independent 

of high pressure up to 12.1 kbar (T. Kanomata et al Phys. Rev. B 82, 144415 (2010)). 

Using the full potential linearized augmented plane-wave method, we here further 

investigate the structural, electronic and magnetic properties of all possible (111) 

surfaces of Co 2VGa. Both structural relaxation and calculated surface energy reveal 

that Ga-terminated surface is more stable than other terminations. From the analysis of 

the spin-polarized density of states, we find that the half-metallicity confirmed in bulk 

Co 2VGa is lost at Co-terminated surfaces but still maintained at V-terminated and Gaterminated 

surfaces. Moreover, the obtained magnetic moments show that the atomic 

magnetic moments of the (111) surfaces are greatly different from the bulk values.

SO02 

Magnetic and resonance properties of Bi 24(CoBi)O 40 

Sergey Stepanovich Aplesnin 1 , Maksim Nicolaevich Sitnikov 1 , Lubov Victorovna 

Udod 2 and Dmitrii Anotol'evich Velicanov 2 

1 M.F. Reshetnev Siberian State Aerospace University, Russia 

2 L.V. Kirensky Institute of Physics, Russia 

The cubic bismuth oxide is characterized by charge ordering of bismuth ions. A study 

of magnetic moment of cobalt ions is used to establish the valence state of bismuth 

ions. The aim of study is to establish the interrelation between spin and elastic 

subsystems. Measurements of the magnetization was carried out over the temperature 

range 4K-300 K in the field H=50 kOe and the magnetization curve M(H) was 

determined at the temperatures T=5 K and T=300 K. The temperature dependence 

of magnetic susceptibility is well fitted to the Curie-Weiss law with the Curie-Weiss 

temperature θ=- 12.3 К and the effective magnetic moment is μ=5.08μB . The bismuth 

cobaltit is paramagnetic at T >4 K. The electron paramagnetic resonance (EPR) 

spectra were recorded from 77 K to 300 K at 9.3 GHz. The g- factor increases versus 

temperature that can be qualitatively explained by local deformation of structure at 

variation of bismuth ion valence. As a result, the magnetic anisotropy field is enhanced 

at the heating. EPR linewidth varies linearly with temperature that is explained by spinphonon 

interaction. Relaxation of magnetic moment is due to strong interaction with 

the elastic lattice. 

SO03 

Field induced phase transitions and magnetocaloric properties in Er 1xLu 

xFe 2O 4 compound 

Peng Zhang 1 , Ying-de Zhang 1 , Young-yeal Song 1 , Jae-yeong Kim 2 , Bo-wha Lee 2 and 

Seong-cho Yu 1 * 

1 Physics, Chungbuk National University, Korea 

2 Physics, Hankuk University of Foreign Studies, Korea 

Rare earth (RE)-ferrites have attracted attention in recent years due to their various 

phase transitions (PTs) near room temperature. Their magnetic phase is determined by 

competition between antiferromagnetic and ferrimagnetic coupling of the localized 

Fe ions. Magnetocaloric effect (MCE) reaches the maximum near the magnetic PT 

temperature. Despite of many works of the PT, however, there are very limited works 

on MCE in the RE-ferrites with two RE elements. In this work one has investigated 

field induced magnetic PT properties and MCE in the vicinity of the PT point. 

Stoichiometric polycrystalline samples of Er 1-xLu xFe 2O 4 (0.1 ≤ x ≤ 0.8) were prepared 

by solid-state reaction method. Magnetic measurements were performed using a 

SQUID magnetometer. Fig.1 gives isothermal M-H curves of Er 0.9Lu 0.1Fe 2O 4, from 

which the field induced PT can be seen clearly from the magnetization curves in the 

range of 208 K-240 K indicating a first order structural type PT[1]. Fig. 2 shows 

magnetic entropy change (ΔSM) curves. With a maximum field of 1 T and 3 T, the 

maximum value of ΔSM are 0.49 J•kg-1K-1and 1.04 J•kg-1K-1 at 249 K, respectively. 

The maximum ΔSM were appeared near the transition temperature and their MCE will 

be explained in terms of PTs. 

SO04 

Magnetic properties of heusler-type Ni-Mn-Ga glass-coated microwires 

Valeria Rodionova 1 , Maxim Ilyn 2 , Valentina Zhukova 2 *, Alexander Granovsky 3 , Alexander 

Aronin 4 , Galina Abrosimova 4 and Arcady Zhukov 5 

1 Dpto. de Fisica de Materiales and Faculty of Physics, UPV/EHU San Sebastian, Lomonosov 

Moscow State University and Immanuel Kant Baltic Federal University, Russia 

2 Dpto. de Fisica de Materiales, UPV/EHU, Spain 

3 Dpto. de Fisica de Materiales and Faculty of Physics, UPV/EHU, San Sebastian, Spain and 

Lomonosov Moscow State University, Moscow, Russia 

4 Insitute of solid State Physics, RAS, Chernogolovka, 142432, Moscow Region, Russia 

5 Dpto. de Fis. Mater., UPV/EHU San Sebastian and IKERBASQUE, Basque Foundation for 

Science, Bilbao, Spain 

Studies of magnetic shape-memory alloys (MSMAs) attracted growing attention within last few years owing 

to significant magnetic-field-induced strain (MFIS) useful for applications in actuators, sensors and for energy 

harvesting. From point of view of applications, miniaturizing of MSMA-based devices based on small-size MSMA 

materials is quite important. Main advantage of Ni-Mn-Ga Heusler-type microwires is related with composite 

character, allowing production of long microwire from brittle Ni-Mn-Ga alloy. Consequently the aim of this paper 

is to present results on Heusler-type Ni 49.5Mn 25.4Ga 25.1 glass-coated microwires. We fabricated few metres long 

microwire and measured magnetization, M, versus magnetic field, H, curves in as-prepared and annealed up to 790 

K microwires. After annealing M(H) curves drastically changed: in as-prepared microwires magnetic transformation 

appears around 175 K. The sample seems contain the second magnetic phase which orders at low temperature 

giving rise to fast increase of the magnetization below 30 K. Meanwhile common ferromagnetic behaviour was 

observed at around 325 K for the annealed sample without any evidence of existence of second magnetic phase. 

X-ray diffraction allows to detect significant structural changes after annealing. Obtained results are discussed taking 

into account strong internal stresses induced by fabrication of composite microwires and high quenching rate. 

SO05 

SO06 

SO07 


Compensated magnetism in double perovskites A 2CrFeO 6 (A=La,Sr) 

Kyo-hoon Ahn 1 and Kwan-woo Lee 2 * 

1 Department of Applied Physics, Graduate School, Korea University, Sejong, Korea 

2 Department of Display and Semiconductor Physics, Korea University, Sejong, Korea 

Precise compensation of magnetic moment in solid state compounds is very rare. An 

example is the so-called half-metallic antiferromagnet (HMAFM), which has one 

metallic spin channel and the other insulating spin channel with the zero net moment. 

Double perovskite compounds of A 2BB’O 6 have been theoretically investigated 

as the most promising candidates for the last 15 years. Very recently, nearly wellordered 

epitaxial La 2CrFeO 6 films, theoretically predicted to be a HMAFM, were 

synthesized using pulsed laser deposition. This sample shows the saturated moment of 

~2 μB, implying the ferrimagnetically ordered S=3/2 Cr 3+ and S=5/2 Fe 3+ . This results 

are controversial to the previous experimental results on artificial LaCrO 3/LaFeO 3 

superlattices, which proposed a ferromagnetic order, as well as the existing theoretical 

predictions. In this presentation, we will revisit this system with first principles 

calculations using LDA+U, the modified Becker-Johnson functional, and fixed spin 

moment. Our results are consistent with the recent experimental results, showing a 

ferrimagnetic insulating La 2CrFeO 6. Furthermore, we have investigated the Sr-analog 

Sr 2CrFeO 6, which is as yet unsynthesized. Contrary to La 2CrFeO 6, this system has the 

tetravalent Cr and Fe ions with antialigned S=1 moments, resulting in zero net moment. 

Our findings suggest a precise HMAFM Sr 2CrFeO 6. 

Possible half-metal antiferromangetism in double perovskites 

A 2VMnO 6 (A=La,Sr) 

Myung-chul Jung 1 , Young-joon Song 1 and Kwan-woo Lee 2 * 

1 Department of Applied Physics, Graduate School,, Korea University, Sejong,, Korea 

2 Department of Display and Semiconductor Physics, Korea University, Sejong,, 

Korea 

A half-metallic antiferromagnet (HMAFM) is half-metallic without macroscopic 

magnetic moment. HMAFM has been considered a promising candidate of a spin 

injector in spintronics, though no true HMAFM has been established yet. Very recently, 

A well-ordered double perovskite La 2VMnO 6, which was theoretically predicted to 

be HMAFM 15 years ago, has been synthesized by pulsed-laser deposition. Contrary 

to the theoretical predictions, the saturated magnetic moment of 2 μB/f.u. implies 

an ferrimagnetically ordered S=1 V 3+ and S=2 Mn 3+ ionic state, below TN=20 K. 

Besides, the synchrotron radiation photoemission measurement indicates an insulating 

La 2VMnO 6 with a gap of 0.9 eV, instead of being half-metallic. In this presentation, 

we will revisit this system using various first principles calculations to unravel these 

discrepancies between the previous theoretical suggestions and the experimental 

results. Furthermore, our calculations suggest that the Sr-analog Sr2VMnO6 is a 

ferrimagnetic half-metal, contrary to the ferrimagnetic insulator La 2VMnO 6. 

Focused magneto-optic kerr effect spectroscopy in Ni 75Fe 25 and Fe 

ferromagnetic thin films on organic substrates 

Kenji Kondo*, Hideo Kaiju and Akira Ishibashi 

Laboratory of Quantum Electronics, Research Institute for Electronic Science, Japan 

We have developed the theory of focused magneto-optic Kerr effect (MOKE) for 

multilayer thin films and applied it to the surface magnetic properties, which have been 

observed by focused MOKE, for Ni 75Fe 25 and Fe thin films evaporated on polyethylene 

naphthalate (PEN) organic substrates. We have experimentally obtained the Ni 75Fe 25 

thickness dependence of Kerr rotations for as-deposited thin films and exposed thin 

films at an atmosphere for 1-year, respectively. The theoretical thickness dependences 

of Kerr rotations have been calculated using magneto-optic constants Q’s of 0.01*exp 

(- i 48π/180) and 0.025*exp (- i 57π/180), respectively. The calculated results are in 

good agreement with the experimental data. Also, the Ni 75Fe 25 thin films exposed for 

1-year show larger magnetization than the as-deposited Ni 75Fe 25 thin films in the range 

of 1-20 nm. We consider that the reason is that the surface of Ni 75Fe 25 has transformed 

to locally Fe-rich surface because of the segregation of Fe. We have also measured the 

Kerr rotations of Fe deposited on PEN. The Q of Fe/PEN was 0.025*exp (- i 47π/180). 

To our knowledge, the magneto-optic constants have been estimated for ferromagnetic 

thin films on PEN for the first time. 


Poster Friday

Poster Friday 

SO08 


The structural and magnetic properties of the magneto-caloric 

compounds Mn0.66Fe1.29P1-xSix (x = 0.34, 0.37 and 0.42) 

Zhiqiang Ou 1 *, L. Zhang 1 , N.h. Dung 1 , L. Van Eijck 2 , M. Avdeev 3 , A.m. Mulders 4 and E. Bruck 1 

1 

FAME Section, R3, Faculty of Applied Sciences, Delft University of Technology, Netherlands 

2 

NPM2 Section, R3, Faculty of Applied Sciences, Delft University of Technology, Netherlands 

3 

Australian Nuclear Science and Technology Organisation,Locked Bag 2001, Kirrawee DC NSW 2232, 

Australia 

4 

School of Physical, Environmental and Mathematical Sciences, UNSW in Canberra, ACT 2610, Australia 

The magneto-caloric effect (MCE) is the thermal response of a magnetic material to an applied magnetic 

field, results in a change of temperature.[1,2] (Mn,Fe)2(P,Si) compounds are known for their potential for 

room-temperature magnetic refrigeration, due to large MCE and tunable working temperatures, cheap 

and abundant raw materials.[3] In this study, the single phase compounds Mn 0.66Fe 1.29P 1-xSi x (x = 0.34, 

0.37 and 0.42) have been synthesized. The crystal and magnetic structure have been investigated by 

means of neutron and X-ray powder diffraction. The refinement shows the compounds crystallize in the 

hexagonal Fe 2P-type structure (P-62m). The 3f site is nearly completely occupied by Fe atoms, the 3g site 

is occupied by Mn atoms and the excess Fe atoms, while the P and Si are randomly mixed. It is shown 

that the average magnetic moment in the 3g site is larger than that in the 3f site, 2.64 versus 1.81 μB for 

the compound with x = 0.34 at 10 K. The alignment of the magnetic moment has changed from almost 

c-direction to a-b plane with increasing Si content from x = 0.34 to x = 0.42. The compounds show a 

strong magnetic field induced transition, small magnetic hysteresis and large magnetic entropy changes. 

[1] V.K. Pecharsky and K.A. Gschneidner, Phys. Rev. Lett. 78, 4494 (1997). [2] E. Bruck, J. Phys D: Appl. Phys. 38, p. R381-R391 (2005). [3] D. T. 

Cam Thanh, E. Bruck, N. T. Trung, J. C. P. Klaasse, K. H. J. Buschow, Z.Q. Ou, O. Tegus and L. Caron, J. Appl. Phys. 103, 07B318 (2008) 

SO09 

Faraday rotation characteristics in wide-gap magnetic semiconductor 

ZnMnTe and ZnMnSe films 

Masaaki Imamura* 

Electrical Engineering, Fukuoka Institute of Technology, Japan 

II-VI based magnetic semiconductors with a wide optical band gap are expected to 

show high potential for optical applications utilizing short wavelength laser diodes, 

such as 532-nm green and 475-nm blue LDs [1]. ZnMnTe and ZnMnSe exhibit their 

absorption edges at 428-544 and 428-458 nm, respectively [2]. The edge is not so 

influenced by the Mn concentration, as is typically observed in CdMnTe. We have 

confirmed that the Faraday rotation in the ZnMnTe films deposited on quartz glass 

substrates is large near the absorption edge. Crystallinity was evaluated using an x-ray 

diffractometer. The preferred (111) growth reported previously for CdMnTe films on 

QG substrates was also observed in the ZnMnTe and ZnMnSe films with weaker peak 

intensities.This paper reports the Faraday rotation angle of those films synthesised on 

QG substrates by using molecular beam epitaxy with a thickness of 2 μm. A Faradayeffect 

signal observed for the ZnMnTe film using a 532-nm green LD has shown that 

ZnMnTe films are useful for green lights.We developed equipment for observing the 

Faraday effect directly under ac magnetic fields generated by a ring magnet. The results 

of a direct Faraday rotation observation sucessfully made for the ZnMnTe films under 

ac fields are shown. 

[1] M. Imamura et al., IEEE Trans. Magn. 42, 3078 (2006). [2] M. Imamura et al., J.Appl.Phys. 99, 

08M706 (2006). 

SO10 

Magnetism and multiplets in Fe-phthalocyanine molecules 

Yukie Kitaoka 1 *, Kohji Nakamura 1 , Toru Akiyama 1 , Tomonori Ito 1 , Michael Weinert 2 

and Arthur J. Freeman 3 

1 Mie University, Japan 

2 University of Wisconsin-Milwaukee, USA 

3 Northwestern University, USA 

A challenge to miniaturize devices for novel magnetic application now extends to treating the 

extreme limit of a single atom or molecule. Moreover, for molecules with transition-metals, 

multiplets are essential aspects of their electronic structure. It is often difficult, however, to 

evaluate such multiplets within a given ligand (or crystal) symmetry. Here, we carry out firstprinciples 

calculations with the FLAPW method[1] for Fe-phthalocyanine (FePc), in which 

the multiplets are treated by imposing a density matrix constraint on the d-orbital occupation 

numbers. Results predict that there are three stationary multiplets - ³Eg (d²xy, d²z2, d³xz+yz), 

³B2g (dxy, dz2, d 4 xz+yz), and ³A2g (d²xy, d²z2, d²xz+yz) - in a single FePc molecule, and total 

energy calculations demonstrate that the ground state is the ³A2g. Furthermore, a columnar 

stacking of the FePc molecules (as seen in α-FePc) changes the ground state to ³Eg due to 

hybridization between adjacent molecules. In qualitative agreement with recent XMCD 

experiments[2], the magnetic anisotropy energy for the columnar stacking structure has a large 

negative value of 0.6 meV/molecule, indicating that the magnetization favors pointing in the 

planar direction, and a large orbital moment of 0.14 μB is induced. 

[1] Wimmer, Krakauer, Weinert, Freeman, PRB 24, 864 (1981); Weinert, Wimmer, Freeman, PRB 26, 4571 (1982). [2] 

Bartolome, Garcia, Filoti, Gredig, Colesniuc, Schuller, Cezar, Phys. Rev. B 81, 195405 (2010). 


SO11 

Elastic anisotropy in ferromagnetic shape memory alloy of nonstoichiometric 

Ni 2MnGa 1-xIn x 

Fumiya Kitanishi*, Kohji Nakamura, Toru Akiyama and Tomonori Ito 

Mie University, Japan 

In magnetic shape memory (MSM) effect, the elastic and magnetocrystalline anisotropies 

play an important role. Moreover, experiments reported an enhancement of the MSE 

effect in a non-stoichiometric metallic compounds.[1] Here, in order to discuss a role 

of the non-stoichiometry, we developed a method for determining elastic property of 

non-stoichiometric compounds from first principles calculations and cluster expansion 

method,[2] and applied to non-stoichiometric Ni 2MnGa 1-xIn x. For calculations, first, 

the formation energies of ordered structures as functions of volume V and c/a, ΔE_ 

o(V,c/a), were calculated by using the FLAPW method.[3] Then, by using the cluster 

expansion method, the formation energy of a disordered state with non-stoichiometric 

compositions, ΔE_o(V,c/a), were obtained in terms of many-body correlation functions. 

Elastic properties of the bulk modulus, B, and the elastic tetragonal anisotropy, 

C’=(C_11-C_12)/2, were numerically obtained from the ΔE_d(V,c/a) of the disordered 

state. Results indicate that the B has an almost linear relation with respect to x. However, 

a deviation from stoichiometric composition is found to enhance the elastic tetragonal 

anisotropy; e.g., for a non-stoichiometric composition of x=0.125, the C’ decreases by 0.4 

GPa compared to that in x=0, and the C’ increases when the x increases over about 0.125. 

[1] R. Kainuma et al., Nature 439, 957 (2006). [2] J. W. D. Connolly and A. R. Williams, Phys. Rev. 

B 59, R2486 (1998). [3] K. Nakamura, et al., Phys. Rev. B 67, 14405 (2003). 

SO12 

Structure and properties of double perovskite system La 2Co 1-xFe xMnO 6 

(x=0, 0.1, 0.2, 0.3) 

The-tan Pham, Huyen-yen Pham and Nam-nhat Hoang* 



Insulating ferromagnets of type RE 2AMnO 6 where A is transition metal and RE rare 

earth have received a renewed interest. Although the bulk La 2CoMnO 6 has been 

extensively studied, its Fe-doped possed several questions that should be addressed. 

The substitution of Fe into the B site induced the increase in ferromagnetism at the 

cost of TC. It was also accompanied by a structure transition from orthorhombic to 

monoclinic. The monoclinic crystal symmetry occurred in the space group P21/n, 

with cell parameters a = 5.532 A, b=5.492 A, c=7.784 A, beta = 89.92°. The magnetic 

measurement showed that the magnetization reached maximum value of 4.7uB/ u.c. 

This value agrees well with the theoretically expected value. 

SO13 

Density-functional study on spin-crossover in several Fe-based 

molecules 

Tuan Anh Nguyen* and Thanh Van Nguyen 

Faculty of Physics, Hanoi University of Science, Viet Nam 

Spin crossover (SCO) complexes are now very potential candidates for applications 

such as molecular switches, display and memory devices [1]. The SCO phenomenon 

can be qualitatively explained by the ligand field model, however, designing transition 

metal complexes with expected SCO behavior is still a big challenge in the field of 

materials science. In this paper, in order to explore more about the way to control 

SCO behavior of transition metal complexes, we present a density functional study 

on the geometric structure, electronic structure and SCO of a series of eight Fe-based 

molecules [2-7]. Our calculated results show that SCO in these Fe-based molecules 

is accompanied with charge transfer between the Fe atom and ligands. This causes 

change in the electrostatic energy (ΔU) as well as the total electronic energy of these 

molecules. Moreover, our calculated results demonstrate an important contribution of 

the interionic interactions to ΔU, and there is the relation between ΔU and the thermal 

hysteresis behavior of SCO in these molecules. These results should be helpful for 

developing new SCO molecules. 

[1]. H. A. Goodwin, et.al., Top. Curr. Chem. 233, 1 (2004). [2]. Nicolas Moliner, et.al., Inorganica Chimica 

Acta, 291, 279 (1999). [3]. B. Weber, W. Bauer, J. Obel, Angew. Chem. Int. Ed. 47, 10098 (2008). [4]. Gaelle 

Dupouy, et.al., Inorg. Chem., 47, 8921 (2008). [5]. B. Weber, et.al., Inorg. Chem. 47, 487 (2008). [6]. B. Weber, 

et.al., Eur. J. Inorg. Chem. 4891 (2008). [7]. B. Weber, et.al., Eur. J. Inorg. Chem. 5527 (2009).

SO14 

Magnetic properties of Cu 70.9Al 18.1Mn 11 ferromagnetic shape memory 

alloy 

S Chatterjee 1 , S Giri 2 and S Majumdar 2 * 

1 UGC-DAE Consortium for Scientific Research, Kolkata Centre, India 

2 Department of Solid State Physics, Indian Association for the Cultivation of Science, 

India 

The ferromagnetic shape memory alloy (FSMA) of nominal composition 

Cu 70.9Mn 11Al 18.1 has been studied through electronic transport, dc magnetization and 

ac susceptibility measurements. Unlike other Cu containing shape memory alloys, 

Cu-Mn-Al systems of alloys show interesting magnetic behaviour. Ferromagnetism 

in Cu-Mn-Al alloys come from the Rudermann-Kittel-Kasuya-Yosida (RKKY) type 

ferromagnetic exchange interaction between Mn atoms. The studied alloy undergoes 

ferromagnetic to glassy transition below martensitic transition (MT). Clear frequency 

shift in ac susceptibility measurement is observed near the step like anomaly present in 

the zero field cooled dc magnetization data, which actually indicates the onset of spin 

glass freezing in the sample. Isothermal magnetization (M) measurement as a function 

of magnetic field (H) at 5K with field cooled condition (sample cooled in presence of 

different magnetic field) has been performed but no shift in M(H) loop is observed. It 

indicates that no exchange pinning is originated in the sample due to field cooling. 

SO15 

Magnetic properties of dioxygen molecules confined in single-walled 

carbon nanotubes 

Yusuke Nakai 1 *, Shin Tadera 1 , Haruka Kyakuno 1 , Keitaro Harada 1 , Kazuyuki 

Matsuda 2 , Kazuhiro Yanagi 1 and Yutaka Maniwa 1 

1 

Department of Physics, Graduate School of Science, Tokyo Metropolitan University, 

Japan 

2 

Faculty of Engineering, Kanagawa University, Japan 

Materials confined in quasi-1D single-walled carbon nanotubes (SWCNTs) exhibits unique 

properties that differ from the bulk counterparts [1]. Among many kinds of intercalates, a 

dioxygen molecule (O 2), which has a spin S = 1 in the ground state, confined in SWCNTs 

may offer well-defined environment to investigate the physics of a quasi-1D spin-1 magnet. 

We present magnetic susceptibility and x-ray diffraction measurements as well as theoretical 

simulations on the dioxygen molecules confined in SWCNTs. Our XRD measurements 

confirmed that the O 2 molecules are absorbed inside the SWCNTs at low temperatures. Our 

magnetic susceptibility data shows the signature of the opening of a gap in spin excitations at 

low temperatures, which differs from bulk O 2 molecules. We interpret this result in terms of 1D 

antiferromagnets with S = 1, which is supported by our first-principles calculation suggesting 

that an isolated O 2 molecule inside a SWCNT of over 0.8 nm in diameter possess a spin S = 1. 

We will also discuss the condensed structure of O 2 inside SWCNTs on the basis of our XRD 

data and molecular dynamics simulations [2]. 

[1] Y. Maniwa et al., Chem. Phys. Lett. 401 (2005) 534. [2] K. Hanami et al., J. Phys. Soc. Jpn. 79 

(2010) 023601. 

SO16 

Magneto-elastic coupling and magnetocaloric effect in Fe 2P-based Mn- 

Fe-P-Si compounds 

N. H. Dung 1 *, L. Zhang2, Z. Q. Ou 1 and E. Bruck 1 

1 Delft University of Technology, Netherlands 

2 BASF Netherlands B.V & Delft University of Technology, Netherlands 

Structural, magnetic and magnetocaloric properties of Fe 2P-based Mn-Fe-P-Si 

compounds were investigated. The study reveals a strong magneto-elastic coupling that 

starts to develop in the paramagnetic state and grows when the ferromagnetic transition 

temperature is approached. This magneto-elastic coupling over a large temperature 

range around the transition temperature results in a first-order phase transition with 

abrupt changes in lattice parameters. Moreover, a correlation is observed between the 

hysteresis and the discontinuous changes in lattice parameters at the transition. The 

gradual development of the magneto-elastic coupling near the transition temperature, 

which is attributed to competition between moment formation and bonding [1], 

contributes to a reduced hysteresis. We also show the thermal evolution of the magnetic 

moments. Interestingly, the magnetic moments on the 3f site are formed and gradually 

increase in the paramagnetic state, and suddenly jump to a larger value when magnetic 

order is established. 

[1] N. H. Dung, Z. Q. Ou, L. Caron, L. Zhang, D. T. Cam Thanh, G. A. de Wijs, R. A. de Groot, K. H. 

J. Buschow, E. Bruck, Adv. Energy Mater. 1, 1215 (2011). 

SO17 

Magnetorefractive effect in manganites 

Andrey Telegin*, Yurii Sukhorukov and Vladimir Bessonov 

Institute of Metal Physics UD of RAS, Russia 

SO18 

SO19 


We studied a magnetic-field-induced change in reflectivity (magnetoreflection) and transmission 

(magnetotransmission) of natural light in La 1-xA xMnO 3 (A=Ca,Sr,K,Ag) manganites possessed the colossal 

magnetoresistance effect (CMR)[1-3]. It was showed the magnetoreflection and magnetotransmission 

effects in manganites are an optical response to the CMR in the IR-region. Effects can reach tens of 

percents in the field of 0.3-1 T near the magnetic phase transition temperature. The observed phenomena 

are connected with the change of ratio between the localized and delocalized charge carriers under the 

magnetic field applied [2]. At the same time, there is no strict correlation between these effects and CMR 

in the visible range. The observed phenomena are connected with the alteration of the optical density 

under the magnetic field in the range of interband transitions [3]. Magnitude of effects is one order as less 

as that in the IR-region. The nature of observed effects in manganites can be satisfactory explained within 

the framework of the theory of magnetorefractive effect [4]. The results of study of magnetoreflection and 

magnetotransmission in manganites may be proposed for creation of different magnetic and electronic 

sensors and light modulators. 

[1] Yu.P. Sukhorukov, A.V. Telegin, A.B. Granovsky et al., J. of Experimental and Theoretical Physics, 138, No 3, 402 (2010). [2] A.B. 

Granovskii, Yu.P. Sukhorukov, A.V. Telegin et al, J. of Experimental and Theoretical Physics, 112, No1, 77 (2011) [3] Yu.P. Sukhorukov, A.V. 

Telegin, A.B. Granovsky et al, J. of Experimental and Theoretical Physics, 141, No1, 160 (2012) [4] Yurasov A.N., Bakhvalova T.N., Telegin A.V. 

et al, Abstracts of the 20th <strong>International</strong> <strong>Conference</strong> on Soft magnetic materials SMM-2011, Greece, 18-22 September, p.244 

Supported by the program of DPS RAS “Physics of new materials and structures”, grant MK-1048.2012.2 and RFBR grants No 

10-02-00038, 11-02-00252, 12-02-00208 

Electroresistance and joule heating effects in manganite thin films 

Luis Pena, Regina Galceran, Zorica Konstantinovic, Alberto Pomar, Bernat Bozzo, 

Lluis Balcells, Felip Sandiumenge and Benjamin Martinez* 

Magnetic Materials and Functional Oxides, ICMAB - CSIC, Spain 

Electroresistance (ER), i.e. electric field- and/or current-induced resistance switching, 

has attracted much attention recently because of the possibility of using it for the 

implementation of resistance random access memories (ReRAM). Although ER is 

a quite common phenomenon in transition metal oxides, that has been extensively 

studied both theoretically and experimentally, the precise mechanism involved is not 

clear yet. In this work we report on the ER measurements in patterned La 2/3Sr 2/3MnO 3 

(LSMO) thin films prepared by sputtering. In order to analyze Joule heating effects 

we have evaporated a Pt layer on top of the LSMO path to have access to the 

actual temperature of the sample while measuring resistance of LSMO path or I(V) 

characteristic curves. I(V) curves have been measured at different temperatures and the 

corresponding resistance values are compared with that of the R(T) curve taking into 

account the actual temperature of the sample in order to clarify the role of Joule heating 

in the observed change of the resistance. 

Magnetocaloric effect and other properties of cold rolled Gd ribbons 

Sergey V. Taskaev 1 , Vasiliy D. Buchelnikov 1 , Igor V. Bychkov 1 , Anatoliy P. Pelennen 2 , Oliver Gutfleisch 3 , 

Konstantin P. Skokov 4 , Vladimir V. Khovaylo 5 , Victor V. Koledov 6 and Vladimir G. Shavrov 6 

1 

Physics department, Chelyabinsk State University, Chelyabinsk, Russia 

2 

South-Ural State University, Chelyabinsk, Russia 

3 

Technische Universitat Darmstadt, Darmstadt, Germany 

4 IFW, Dresden, Germany 

5 MISIS, Moscow, Russia 

6 IRE RAS, Moscow, Russia 

The number of papers devoted to magnetic refrigeration, magnetocaloric materials and high-field magnetic 

systems has grown at an exponential rate in the past 10 years (K.A. Gschneidner et al., 2008) [1]. Since First 

<strong>International</strong> <strong>Conference</strong> on Magnetic Refrigeration at Room Temperature many researches in different countries 

mobilize their efforts in the field of constructing commercial magnetic refrigerator. There are numerous different 

magnetocaloric alloys such as La-Fe-Si, Gd-Si-Ge, Ni-Mn-X (X = Ga, In, Sn, Sb) [2-3]. Usually the magnetic 

refrigerant materials are either packed in a magnetocaloric bed as small spheres attached around a disk as a ribbon 

or separated in a pile of thin, equally spaced sheets. Thus one the ways of engineering MCE materials is tightly 

connected with preparing very thin (a few microns) ribbons of high value MCE alloys with good mechanical 

properties. At present rapid solidification is the main technique for producing this kind of materials [4]. In our 

work we investigate magnetocaloric effect, magnetic and mechanical properties of Gd cold rolled samples of 

different thickness. Both theoretical and experimental aspects of the investigation are discussed. 

1. Gschneidner K.A. Jr. et al. Thirty years of near room temperature magnetic cooling: Where we are today and future prospects, Int. J. Refrig, 31, 945 (2008). 

2. A. Planes, L. Manosa, and M. Acet, J. Phys.: Condens. Matter 21, 233201 (2009). 3. X. Moya, L. Manosa, A. Planes, S. Aksoy, M. Acet, E. Wassermann, and 

T. Krenke, Phys. Rev. B. 75, 184412 (2007). 4. P. M. Shan et al. Magnetic behavior of melt-spun gadolinium, Phys. Rev. B. 77, 184415 (2008). 


Poster Friday

Poster Friday 

SO20 


Fabrication and properties of double perovskite SrLaVRuO 6 

Ryosuke Zenzai*, Tetsuya Miyawaki, Kenji Ueda and Hidefumi Asano 


Half-metallic antiferromagnets (HMAF) exhibiting both fully spin-polarized charge 

transport and zero net magnetic moment are expected to provide not only a fertile 

playground for fundamental research but also new spintronic devices. Although the 

theoretical calculations predicted candidates for HMAFs, experimental searches for 

HMAFs have so far been unsuccessful. This paper reports on the fabrication and 

properties of SrLaVRuO 6 polycrystalline bulks and epitaxial films. SrLaVRuO 6 bulks 

were synthesized by a solid-state reaction at 1100~1350 °C in Ar + (0~3) % H 2 gas. 

Structural characterization revealed that the main phase of the bulk samples was of 

a double perovskite crystal structure with lattice parameters of 0.7888~0.7905 nm. 

However, all the bulks contained the impurity phase (Sr 3V 2O 8), which is a nonmagnetic 

semiconductor. The bulks exhibited magnetization values of 10-3 μB per formula unit 

at 77 K, negative paramagnetic Curie temperature values and metallic temperature 

dependence of the resistivity. These properties are assumed to be intrinsic to double 

perovskite SrLaVRuO 6 by considering the nonmagnetic semiconducting nature of 

Sr 3V 2O 8. Moreover, SrLaVRuO 6 thin films were prepared on LaAlO 3, SrTiO 3 (001) 

substrates by magnetron sputtering. Structural characterization revealed that these thin 

films were grown epitaxially on these substrates, and phase pure double perovskite. 

J. H. Park, S. K. Kwon, and B. I. Min, Phys. Rev. B 65 (2002) 174401. 

SO21 

Giant magnetoresistive effect in non-magnetic silicon 

Tae Ho Lee 1 , Hong-seok Kim 1 , Woo Lee 2 and Yong-joo Doh 1 * 

1 

Dept. of Display and Semiconductor Physics, Korea University Sejong Campus, 

Korea 

2 


Recently magnetoresistive effects in non-magnetic semiconductors, particularly 

silicon, have gained considerable attention owing to the large magnitude of the effect, 

which is comparable, or even larger than, that of the performance of commercial 

giant-magnetoresistance devices. The underlying mechanism responsible for the giant 

magnetoresistance in silicon, however, has not yet been fully explored. Here we report 

that a simple device, based on a lightly doped silicon substrate contacted with two 

indium contacts, shows a positive magnetoresistance over 10,000 per cent for magnetic 

fields between 0 and 1 T at low temperature of 3 K. Current-voltage characteristics 

exhibit a nonlinear behavior, which is highly sensitive to temperature and magnetic 

field. We have extensively studied magnetoresistive effect in silicon with varying bias 

voltage, temperature, electrode spacing, and the relative angle between the substrate 

and the applied magnetic field. Since our device is based on a conventional silicon 

platform and is highly sensitive to low magnetic field, it could be used to develop new 

devices of silicon-based magnetoelectronics. 

SO22 

Effect of Fe substitution on Ni-Mn-In shape memory alloys: Magnetic 

and magneto-structural properties 

Radha S 1 , Ashwin Mohan 2 and A. K. Nigam 2 * 


2 Department of Condensed Matter Physics and Materials Science, Tata Institute of 

Fundamental Research, India 

The Ni-Mn based ferromagnetic shape memory alloys have been extensively investigated for their 

multifunctional properties emerging by suitable chemical substitutions. The off-stoichiometric Ni 50Mn 25+xIn 25-x 

exhibit martensitic transition for In concentration in the range 13-16 at%. In the Ni 50Mn 35In 15 alloy, the 

ferromagnetic transition occurs at Curie temperature TC = 305 K with a concommitant austenite to martensitic 

transition. A large inverse magnetocaloric effect and anomalous magnetic behavior have earlier been reported 

for this alloy [1]. The present work reports the effect of Fe-substitution (0.5 to 2 at%) on the magneto-structural 

transition and magnetic behavior of the Ni 50Mn 35In 15 alloy. The martensitic transition goes down to 255 K for 

1at% Fe alloy with strong hysteresis between zero field-cooled (ZFC) and field-cooled (FC) data while it nearly 

disappears for the 2at% Fe alloy. The 0.5 at% Fe substituted alloy shows a temperature dependent field-induced 

metamagnetic transition between 250-220K while this transition is not observed up to fields of 6T in 1at% Fe 

substituted alloy. A thermal hysteresis in the temperature dependence of resistance is observed between heating 

and cooling cycles due to austenitic-martensitic transitions up to 1 at% Fe substitution. The substitution of 2 at% 

Fe suppresses the martensitic transition without affecting the ferromagnetic transition. 

[1] P.A. Bhobe, K.R. Priolkar and A.K. Nigam, Appl. Phys. Lett. 91 (2007) 242503 


SO23 

Magnetic properties and magnetocaloric effect in shape memory alloys 

Ni-Mn-Ga 

Rafael Fayzullin, Vasiliy Buchelnikov, Sergey Taskaev and Mikhail Drobosyuk 

Chelyabinsk State University, Russia 

The magnetocaloric effect (MCE) is the ability of magnetic materials to heat up or 

cool down when placed in or removed from an external magnetic field. The magnetic 

materials with large values of MCE can be applied in the magnetic refrigeration 

technique [1]. Recent experimental studies have shown that Ni-Mn-Ga Heusler alloys are 

also attractive for the application in magnetic refrigeration [2]. In this work the magnetic 

and magnetocaloric properties of the ferromagnetic shape memory alloys Ni 2+xMn 1xGa 

(x=0.07; 0.08; 0.09) were experimentally studied. The MCE measurements were 

performed by the setup produced by AMT&C [3]. In this setup, the adiabatic temperature 

change ΔTad was measured by a direct method with help of a thermocouple. Magnetic 

field up to 2 T was created by Halbach permanent magnet. The magnetic field strength 

was measured by Hall probe. Signals from the thermocouple and Hall probe were 

recorded simultaneously what allowed us to measure ΔTad as a function of magnetic field 

H. All alloys exhibit the positive MCE typical near the second-order phase. Our MCE 

measurements of Ni 2+xMn 1-xGa have shown that the maximal MCE is observed near the 

Curie point. The maximal values of MCE are 1.2 - 1.6 K near the room temperature. 

[1] K. Gschneidner, Jr. and V.K. Pecharsky, Int. J. Refrig., 31 (2008) 945. [2] A. Planes, L. Manosa, 

and M. Acet, J. Phys.: Condens. Matter. 21 (2009) 233201. [3] Y.I. Spichkin, et al, Proc. 3rd IIF-IIR 

Intern. Conf. Magnetic Refrigeration at Room Temperature, IIF/IIR (2009) 173. 

SO24 

Magnetic susceptibility avalanches in thermally-induced first-order 

phase transition of La(Fe 0.88Si 0.12) 13 magnetocaloric compound 

Asaya Fujita* and Hitomi Yako 

Department of Materials Science, Tohoku University, Japan 

Magnetic materials with large magnetocaloric effects due to the first-order phase transition 

attract attention as candidates for room temperature magnetic refrigerants. NaZn 13type 

La(Fe xSi 1-x) 13 compounds exhibit thermally-induced first-order ferromagnetic (F) - 

paramagnetic (P) transition at the Curie temperature Tc and the itinerant-electron metamagnetic 

transition takes place above Tc [1]. Evolution of the transition determines the operating speed 

of magnetic refrigeration, therefore, a detailed observation is necessary. In the present study, 

appearance of the avalanche behavior [2] in the progress of thermally-induced transition has 

been examined by measuring the magnetic susceptibility χ. The value of χ upon cooling at 

0.4 K / min. exhibits a smooth variation across the transition and its first derivative, dχ/dT, 

shows no jerky change. Meanwhile, the avalanche-like behavior is observed in dχ/dT around 

Tc upon heating. Furthermore, the number and height of avalanches are dramatically changed 

by external magnetic fields. Generally, the avalanche behavior is induced by the quenched 

disorders, however, such a mechanism can not explain the influence of magnetic field. 

Considering the fact that the kinetics of the transition is influenced by the demagnetization 

effect [3], these results indicate that the nucleation- growth behavior is affected by the magnetic 

dipole interaction. 

[1] A. Fujita, S. Fujieda, Y. Hasegawa, K. Fukamichi: Phys. Rev. B 67 (2003), 104416. [2] E. Vives, J. Ortin, L. Manosa, I. Rafols, R. Perez-Magrane, A. 

Planes: Phys. Rev. Lett. 72 (1994), 1694. [3] H. Yako, S. Fujieda, A. Fujita, K. Fukamichi: IEEE Trans. Magn. 47 (2011), 2482. 

SO25 

Phase coexistence and magnetocaloric effect on martensitic transition 

in Ni-Co-Mn-Sn metamagnetic shape memory alloy 

Bo Gao 1 *, Wen Guan 1 , Yu Wang 1 , Sen Yang 1 , Xiaoping Song 1 , Fengxia Hu 2 , Jirong Sun 2 and 

Baogen Shen 2 

1 

MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an 

Jiaotong University, China 

2 

State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, China 

Since the discovery of the metamagnetic shape memory effect in Ni 45Co 5Mn 36.7In 13.3 Heusler alloys [1], a member 

of studies on magnetocaloric effect (MCE) have been made in metamagnetic shape memory alloys. It is found 

that metamagnetic shape memory alloys exhibit large MCE in the vicinity of martensitic transformation. But for 

the first-order transition, whether and to what extent the Maxwell relation is applicable are problems requiring 

further study [2]. In this paper, we will discuss the appropriate approach to evaluate the MCE in Ni-Co-Mn- 

Sn alloys. The energy dispersive spectrometer shows that the sample composition is Ni 43.2Co 3.1Mn 41.8Sn 11.9. The 

thermo-magnetic curves indicate the martensitic transformation can be driven by the magnetic field. It is observed 

that metamagnetic transition takes place in a wide temperature range from the magnetization isotherms. The 

entropy change calculated by Maxwell relation is up to 30J/kgK under a field change of 0-5T. Meanwhile, we 

calculated the entropy change based on heat capacity measured under 0 and 5T, and an entropy change of ~3J/ 

kgK is obtained for a field change of 0-5T. According to the different results from magnetic and calorimetric 

measurements, we find that the Maxwell relation should be used with caution on martensitic transformation 

including phase coexistence. 

[1] R. Kainuma, Y. Imano, W. Ito, Y. Sutou, H. Morito, S. Okamoto, O. Kitakami, K. Oikawa, A. Fujita, T. Kanomata, and K. Ishida, Nature 439, 957 (2006) 

[2] G. J. Liu, J. R. Sun, J. Shen, B. Gao, H. W. Zhang, F. X. Hu, and B. G. Shen, Appl. Phys. Lett. 90, 032507 (2007)

SO26 

Balance between the growth rate of ferromagnetic phase and 

demagnetizing fields in itinerant electron metamagnetic transition of 

La(Fe 0.88Si 0.12) 13 

Hitomi Yako* and Asaya Fujita 

Tohoku university, Japan 

Strong interplay between an itinerant electron metamagnetic (IEM) transition and 

magnetocaloric effects in NaZn 13-type La(FexSi1-x)13 has been investigated.[1-3] Recently, 

we have demonstrated that progress of the IEM transition is influenced by the demagnetization 

effect in La(Fe 0.88Si 0.12) 13.[4] Especially, the progress is arrested in midstream even under the 

magnetic fields, μH larger than the critical value, μHc by setting longitudinal direction of the 

sample perpendicular to the field direction ( θ = 90 degrees ). In the present study, the angular 

dependence of the transition progress is examined and the influence of demagnetization effect 

on the IEM transition is discussed. The time-dependent magnetization measurements were 

carried out at 200 K under the constant value of μH by changing θ from 0 to 90 degrees. The 

transition starts to proceed under the magnetic field larger than μHs. However, the transition 

is arrested in midstream, and the completion of transition emerges only after μHc exceeds the 

threshold value, μHt. The values of μHs and μHt are evaluated to be 0.60 and 0.75 T for θ = 

30 degrees and 0.70 and 1.00 T for 90 degrees, respectively. The growth rate of ferromagnetic 

phase is dominated by keeping the balance with demagnetizing fields. 

[1] A. Fujita et al., J. Appl. Phys., 85, 4756-4758, ( 1999 ). [2] F. X. Hu et al., Appl. Phys. Lett., 78, 3675-3677, ( 2001 ). [3] O. 

Gutfleisch et al., J. Appl. Phys., 97, 10M305:1-10M305:3, ( 2005 ). [4] H. Yako et al., IEEE Trans, Mag., 47, 2482-2485, ( 2011 ). 

SO27 

Temperature dependent structural and magnetic properties of Ni-Mn- 

In Heusler alloy glass-coated microwires 

Valeria Rodionova 1 *, Mikhail Ipatov 2 , Maxim Ilyn 3 , Valentina Zhukova 4 , Alexander Granovsky 5 and Arcady Zhukov 6 

1 

I. Kant Baltic Federal University, UPV/EHU, Lomonosov Moscow State University, Russia 

2 

UPV/EHU, Spain 

3 

Centro de Fisica de Materiales, CSIC/UPV, Spain 

4 

Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU, Spain 

5 

Lomonosov Moscow State University, IKERBASQUE, Basque Foundation for Science, Russia 

6 

Dpto. Fisica de Materiales, Fac. Quimicas, UPV/EHU,IKERBASQUE, Basque Foundation for Science, Spain 

Magnetic shape-memory alloys (MSMAs) attracted growing attention owing to shape memory effect, originated from the 

coupling between magnetic and structural ordering. From point of view of technological applications, miniaturizing of MSMAbased 

devices using MSMA particles, wires, ribbons, films, bi- and multilayers, pillars is quite important. Here we report on 

studies of magnetic properties of non-stoichiometric Heusler-type Ni 50Mn 34.5In1 5.5, Ni 48Co 2Mn 35In 15 and Ni 49.5Mn 25.4Ga 25.1 glasscoated 

microwires prepared using Taylor-Ulitovsky technique. The principle interest in glass-coated microwires is related 

with their composite character allowing to control the strength of internal stresses. We measured magnetization curves at 

different temperatures. As-prepared microwires did not show ferromagnetic ordering at room temperature. From temperature 

dependence of magnetization we found that annealed microwires showed Curie temperature about 270 K (Ni 50Mn 34.5In 15.5 

microwires), between 225K and 240 K (Ni 48Co 2Mn 35In 15 microwires with different metallic nucleus diameters) and 315 K for 

Ni 49.5Mn 25.4Ga 25.1. Microwires Ni 50Mn 34.5In 15.5, Ni 48Co 2Mn 35In 15 and Ni 49.5Mn 25.4Ga 25.1 exhibited phase transition at 240 K, 115 

K and 300 K respectively. From point of view of applications the most promising properties exhibit thinnest Ni 49.5Mn 25.4Ga 25.1 

microwire (with metallic nucleus diameter 10,4 mkm and total diameter of 16 mkm) showing the phase transition near Curie 

temperature. 

SO28 

Magnetooptical Kerr effect enhancement in Co/TiO 2 layered films 

Victor Polyakov 1 , Konstantin Patrin 1 , Klaudia Polyakova 1 *, Vitaly Seredkin 1 and 

Gennady Patrin 2 

1 L.V. Kirensky Institute of Physics, SB RAS, Russia 


As is known, the magneto-optical properties of the composite metal-dielectric systems 

are determined by the volume of a magnetic phase and the properties of a dielectric 

matrix or dielectric layers. Of special interest are the magneto-optical properties of the 

composite films containing TiO 2 whose permittivity is higher as compared to SiO 2 and 

Al 2O 3. Here, we report the results of the magneto-optical study of Co/TiO 2 multilayers. 

Particularly we studied spectral dependence of the polar Kerr effect of Co / TiO 2 

layered structure of with various number of layers. The composite Co/TiO 2 periodic 

structures consisting of 2--12 pairs of layers (n) were prepared by sequential deposition 

of Co and titanium oxide by ion-plasma sputtering and reactive ion-plasma sputtering, 

respectively, onto glass substrates. The respective thicknesses of magnetic and titanium 

oxide layers were 5 and 17 nm. Study of spectral dependence of polar Kerr effect 

showed that the spectra of the Co/TiO 2 layered structures are resonance, with the large 

growth of the angle of rotation near the resonance. The maximum angle of rotation 

nonmonotonically depends on the number of layers. The maximum Kerr rotation angle 

(2θk=7.3 deg) observed at a wavelength of 540 nm corresponds to n = 8. 

SO29 

SO30 

Disorder effects in giant magnetocaloric materials 

Joao S Amaral*, Soma Das and Vitor S Amaral 

CICECO and Dept. of Physics, Universidade de Aveiro, Portugal 

SO31 


Electronic structure calculations and the magnetic properties of 

Ru 2FeZ (Z = Al and Ga) 

Ramesh Kumar K and Thamizhavel A* 

Department of Condensed Matter Physics and Materials Science, Tata Institute of 

Fundamental Research Mumbai 400005, India 

After the discovery of half-metallic character in NiMnSb by de Groot et al. Heusler 

alloys have drawn much attention due to the possible application in magneto-electronic 

devices [1,2]. In the quest of finding half-metallic character in 4d transition element 

based Heusler alloy we present the electronic structure and magnetic properties 

of Ru 2FeGa/Al. The band structure calculations were done using the state-of-theart 

density functional technique with the PWSCF code [3]. The equilibrium lattice 

parameter was found by fitting energy vs volume data to the Murghnan equation of 

state. At the equilibrium lattice parameter the total energy difference between the nonmagnetic 

state and ferromagnetic state was observed to be of the order of 5 meV which 

suggest that these systems are having stable magnetic ground state. In ferromagnetic 

ground state the lattice parameter was observed to be 5.988 A for Ru 2FeGa and 5.982 

A for Ru 2FeAl. From the DOS Vs Energy diagram it is found that the systems are not 

half-metallic in nature. However, the calculation showed very high spin polarization at 

the Fermi level. The spin polarization (P) value was found to be 83 % in both the cases. 

1. R. A. de Groot, F. M. Mueller, P. G. van Engen and K.H. J. Buschow , Phys. Rev. Lett. 50 2024 

(1983). 2. C. Felser, G. H. Fecher, and B. Balke Angew. Chem. Int. Ed., 46 688 (2007). 3. S. Baroni 

et al http://www.pwscf.org/ 

In striving for mass production of magnetocaloric materials for refrigeration applications, one 

has to face the fact that these will not be laboratory-grade materials, and will necessarily present 

composition gradients due to lower quality reagents. Some consequences are expected: the 

maximum value of magnetic entropy change (ΔSM) should decrease compared to a “pure” 

material, and broadening of the ΔSM(T) curves, as observed in elementary ferromagnets [1]. 

Some theoretical work has focused on this topic, for second-order phase transition systems [2- 

5]. Still, these theoretical considerations do not directly apply to giant magnetocaloric materials. 

We present a study on the effect of disorder on the magnetic and magnetocaloric properties 

of first-order phase transition systems, via the use of the Bean-Rodbell [6] model. Disorder is 

shown to “smooth” the discontinuities on magnetization and ΔSM, and also affect magnetic 

hysteresis. For sufficiently large disorder, the ΔSM(T) curves resemble the distribution function. 

We discuss how the magnetic field dependence of ΔSM is affected by disorder, in light of a 

“second-order like” dependence of ΔSM on applied magnetic field, for disordered LaFeSi 

samples [5]. Aging effects on hydrogenated LaFeSi samples, that degrade even in storage [7], 

are discussed taking into account our theoretical simulations. 

[1] Gschneidner Jr. K. A., Pecharsky V. K., Tsokol A. O., 2005, Rep. Prog. Phys. 58 1479. [2] Romanov A. Y., V. P. 

Silin V. P., 1997, Phys. Met. Metallogr. 83, 111. [3] Amaral J. S. et al., 2008, J. Non-Cryst. Solids 354, 5301. [4] 

Bahl C. R. H., et al., 2011, J. Magn. Magn. Mat. 324 564. [5] Lyubina J. et al., 2011 Phys. Rev. B. 83 012403. [6] 

Bean C. P., Rodbell D. S., 1962, Phys. Rev. 126 104. [7] Barcza, A. et al., 2011, IEEE Trans. Magn. 47 3391. 

On the Curie temperature dependency of the Magnetocaloric effect 

Joao H Belo 1 , Joao S Amaral 2 *, Andre M Pereira 1 , Soma Das 2 , Vitor S Amaral 2 and 

Joao P Araujo 1 

1 IFIMUP and IN, Dept. de Fisica e Astronomia, FCUP, 4169-007 Porto, Portugal 

2 CICECO and Dept. of Physics, Universidade de Aveiro, Portugal 

A theoretical study of the magnetcaloric effect dependency on simple ferromagnetic 

microscopic parameters is here presented. Considering the Bean-Rodbell model [1] of 

magnetovolume coupling within the Weiss mean field theory, the magnetic entropy change 

of systems undergoing first and second order magnetic phase transition was numerically 

simulated. Through these simulations, the magnetic entropy change behavior was studied as 

a function of: Tc , spin value, applied field changes and the nature of the transition considered. 

The main result found for both first and second order magnetic transitions systems is the linear 

dependency of the ΔSM(T) maximum value on Tc 2/3 . By starting from the magnetization mean 

field state equation an approximated expression for the magnetic entropy change as a function 

of microscopic magnetic parameters was reached, confirming the Tc 2/3 dependency. We have 

found that many ferromagnetic systems, both undergoing second (GdTbCo [2], RR’Al [3] (R = 

rare earth), RCoMn [4]) and first-order (MnFePAs [5], GdSiGe [7], RCo [7]) phase transitions, 

obey this relation between the magnetocaloric effect and Tc. 

[1] Bean C. P., Rodbell D. S., 1962, Phys. Rev. 126 104. [2] K. Zhou et al. Solid State Commun. 137, 

275 (2006). [3] N. Duc, D. Anh, and P. Brommer, Physica B - Cond. Matter 319, 1 (2002). [4] A. K. 

Pathak et al., J. Magn. Magn. Mater. 323, 2436 (2011). [5] O. Tegus et al., Physica B - Cond. Matter 

319, 174 (2002). [6] K. A. Gschneidner, V. K. Pecharsky, and A. O. Tsokol, Rep. Prog. Phys. 68, 1479 

(2005). [7] N. Duc, D. Anh, and P. Brommer, Physica B - Cond. Matter 319, 1 (2002). 


Poster Friday

POSTER - 19th International Conference on Magnetism

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