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O-19 27 From cuprates to pnictides: inherent duality in HT c -materials (A new playground for NMR/NQR studies?) Lev Gor’kov 1 , Gregory Teitel’baum 2 1 NHMFL, Tallahassee FL 32310, USA 2 E.K. Zavoiskii Institute of the RAS, 420029 Kazan, Russia The heterogeneous coexistence of antiferromagnetism (SDW) and superconductivity on a mesoscopic scale was observed in iron-pnictides in many recent experiments. We suggest and discuss the scenario in which the heterogeneity is caused by formation of domain walls inherent to the SDW state of pnictides at a proper doping or under applied pressure. Superconductivity would emerge from the modulated SDW structure. The phenomenon is akin to the FFLO-phase in superconductors. The local suppression of SDW gap in a domain wall results in a finite density of states, corresponding to charge carriers moving along the walls. By analogy to cuprates, such domain walls may be considered as stripes. It is important that in both families of HT c compounds the spatial scales for heterogeneity vary in the range from one atomic size and up to thousands of angstroms. We discuss experiments that prove that SC in pnictides indeed emerges on the background of the soliton state and specially focus on the problems which may be studied with a help of NMR/NQR. The work of L.P.G. was supported by the NHMFL through NSF cooperative agreement DMR-0654118 and the State of Florida, that of G.B.T. through the RFBR Grant N 10-02-01056.
O-20 28 Magnetic and physical properties of giant-unit-cell intermetallics Magdalena Wencka 1 1 Institute of Molecular Physics, Polish Academy of Sciences, Poznan, Poland Large unit cells containing up to a few thousand atoms, well organized clusters forming shells (often of icosahedral symmetry), an disorder caused by mixed occupancy of atoms at the same positions in unit cells and long range order are characteristic for quasicrystals. Such structure brings about untypical hybridization effects responsible for the formation of a pseudogap at the Fermi energy level. In such systems, electrons cannot move freely (the electronic conductivity is small), the atoms cannot oscillate collectively and exchange energy in the usual way (the heat conductivity is small) and electrons inbetween atoms bind the atoms stiffer to each other (the elasticy constant is very high at room temperature). The magnetic and physical properties, the specific heat and the electronic and thermal transport manifest themselves in the surface energy, the solid-solid friction, the wetting and the extraordinary mechanical properties. Thus quasicrystals are highly applicable alloys used in surface engineering as thick coatings, functional top surfaces to promote selectively specific reactions in catalysis, small mechanical devices requiring extreme elastic properties and for thermoelectric generators and fuel cells. Various properties of quasicrystals and their aproximants belonging to the Al-Ni-Co, Al-Pd-(Mn,Re), Al-Cu- (Ni,Fe), Zr-Cu-Ni-Al, Al-Mn-Fe, Al-Fe-Ni and Yb-Cu families synthesized in numerous phases will be presented. The overview through the physical phenomena in of the giant-unit-cell solids will be given beginning from the NMR. As spin probes, the 27 Al, 59 Co, 63 Cu and 1 H were used. For quasicrystals, a slow, low-energy, diffusive atomic motions persist down to low temperatures. The hydrogen diffusion constant exhibits strong temperature dependence and obeys classical Arrhenius thermally activated over-barrier hopping. The metallic Korringa relation shows in quasicrystaline lattices the cancellation of Kondo screening of the f-moments. The 1-D and 2-D NMR results will be supported by EPR, µ-SR, PPMS and SQUID measurements to show the investigated physical phenomenon from several points of view.
Page 1 and 2: ABSTRACT BOOK RECENT ADVANCES IN BR
Page 3 and 4: RECENT ADVANCES IN BROAD BAND SOLID
Page 9 and 10: INVITED LECTURES
Page 11 and 12: O-2 10 NMR in Quantum Spin Systems
Page 13 and 14: O-4 12 NMR and the quasi-one dimens
Page 15 and 16: O-7 14 NMR studies on the new iron
Page 17 and 18: O-9 16 NMR methods for investigatio
Page 19 and 20: O-10 18 Sodium cobaltates: A golden
Page 21 and 22: O-12 20 Broadband NMR at ultra high
Page 23 and 24: O-14 22 Strong Cu-O hybridization i
Page 25 and 26: O-16 24 Kagome Frustrated Antiferro
Page 27: O-18 26 Multiband Superconductivity
Page 31 and 32: O-21 30 NMR spin echo study of RF-I
Page 33 and 34: O-23 32 Clarification of Quantum Cr
Page 35 and 36: O-25 34 Nanoscale electronic order
Page 37 and 38: O-27 36 75 As NMR in Fe pnictide su
Page 39 and 40: O-29 38 NQR study of the phase segr
Page 41 and 42: O-31 40 NMR study of the Tomonaga-L
Page 43 and 44: POSTER CONTRIBUTIONS
Page 45 and 46: P-2 44 Cryogenic static and magic-a
Page 47 and 48: P-4 46 Nuclear Magnetic Resonance E
Page 49 and 50: P-6 48 Charge Induced Vortex Lattic
Page 51 and 52: P-8 50 77 Se NMR study of λ-(BETS)
Page 53 and 54: P-9 52 Electron spin relaxation in
Page 55 and 56: P-10 54 saturation field B c = 14.9
Page 57 and 58: P-12 56 Superionic Conductivity and
Page 59 and 60: P-14 58 NMR study of Quantum Critic
Page 61 and 62: P-16 60 Gap structure and vortex dy
Page 63 and 64: P-18 62 New Facility for Broadband
Page 65 and 66: P-20 64 Complex interplay of Ce 4f
Page 67 and 68: P-21 66 in our experiment. However,
Page 69 and 70: P-23 68 Observation of the Fermi Li
Page 71 and 72: P-25 70 Magnetic-field induced phas
Page 79 and 80:
RECENT ADVANCES IN BROAD BAND SOLID
Page 81 and 82:
RECENT ADVANCES IN BROAD BAND SOLID
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