Poster Session I - University of Ulsan

may.ulsan.ac.kr

Poster Session I - University of Ulsan

The 9th Korea-Japan Conference on

Ferroelectrics

KJC-FE09

University of Ulsan, Ulsan, Korea

August 7-10, 2012


Committee members of KJC-FE09

Advisory Committee

Organization

Committee

Sook-Il Kwun * Seoul National University

Sunggi Baik Pohang University of Science and Technology

Sung Ho Cho Korea University

Min Su Jang Pusan National University

Jong-Jean Kim

Korea Advanced Institute of Science and

Technology

Gwang Seo Park Sogang University

Yoshihiro

Ishibashi

Kyushu University

Yukio Noda Tohoku University

Masanori

Okuyama

Osaka University

Masaru Shimizu University of Hyogo

Masaharu

Tokunaga

Hokkaido University

Toshirou Yagi Hokkaido University

Ill Won Kim * University of Ulsan

Hyun Myung Jang Pohang University of Science and Technology

Yoon Hee Jeong Pohang University of Science and Technology

Jaichan Lee Sungkyunkwan University

Tae Won Noh Seoul National University

Chul Hong Park Pusan National University

Yoshihiro Kuroiwa Hiroshima University

Yukikuni Akishige Shimane University

Yasuo Cho Tohoku University

Seiji Kojima University of Tsukuba

Shigeo Mori Osaka Prefecture University

Hitoshi Tabata The University of Tokyo


Committee members of KJC-FE09

Program Committee

Publication Committee

Local Committee

Sungkyun Park * Pusan National University

Sang Don Bu Chonbuk National University

Myong Pyo Chun KICET

Cheol Seong Hwang Seoul National University

Sang-Su Kim Changwon National University

Sang-Woo Kim Sungkyunkwan University

Hee Young Lee Yeungnam University

Yunsang Lee Soongsil University

Kazumi Kato AIST

Norifumi Fujimura Osaka Prefecture University

Naoshi Ikeda Okayama University

Makoto Iwata Nagoya Institute Technology

Hiroki Moriwake JFCC

Yuji Noguchi The University of Tokyo

Yoon-Hwae Hwang * Pusan National University

Jai Seok Ahn Pusan National University

DaeYong Jeong Myongji University

Jong-Sook Lee Chonnam National University

Tae Kwon Song Changwon National University

Ken-ichi Kakimoto Nagoya Institute Technology

Hironori Fujisawa University of Hyogo

Hiroyuki Kimura Tohoku University

Chikako Moriyoshi Hiroshima University

Minoru Noda Kyoto Institute Technology

Satoshi Wada University of Yamanashi

Young-Han Shin *

Chang Won Ahn

Shinuk Cho

Hye-Jung Kim

Yong Soo Kim

Jae-Shin Lee

University of Ulsan

* Chairs of the committees


Welcome to KJC-FE09

We are pleased to announce that the 9th Korea-Japan Conference on

Ferroelectrics (KJC-FE09) will be held in Ulsan, Korea from the 7th

(Tuesday) to the 10th (Friday) of August, 2012. The conference will be

hosted by University of Ulsan with the collaboration of the Research

Center for Dielectric and Advanced Matter Physics at Pusan

National University.

The conference has been continued with the successful previous meetings,

held first at Pusan National University in 1994, followed by Hokkaido

University in 1996, Kyongju TEMF Hotel in 1999, Osaka University in

2002, Seoul National University in 2004, Tohoku University in 2006,

Cheju National University in 2008, and Egret Himeji in 2010.

The conference will cover all areas of ferroelectrics in both theories and

experiments, ranging from fundamentals to applications. The primary goal

of the conference is to promote binational cooperation between Korean and

Japanese scientists and to exchange new ideas and results of ferroelectrics

research.

Presentations, oral and poster, of original research on ferroelectrics and

related materials are cordially invited. Students and young researchers are

particularly encouraged to participate and share the spirit of the conference.

Conference chairs, Ill Won Kim and Yoshihiro Kuroiwa


S p o n s o r s

University of Ulsan

http://www.ulsan.ac.kr

Energy Harvest-Storage Research Center

(EHSRC) at University of Ulsan

http://phys.ulsan.ac.kr

The Institute for Basic Sciences at

Changwon National University

http://portal.changwon.ac.kr/home/sbasic

NEXTRON

http://www.nextron.co.kr

AMS KOREA

http://www.amskorea.net


Campus Map of University of Ulsan


The detailed map around the International Building

The route between the International Building and the Heasong Hall

The route between the MainGate and the International Building


Floor plans of the International Building

101

Oral

Sessions

Poster

Sessions I & II

Gallery


Floor plan of the Mugeo Dormitory


August 7

(Tue)

August 8

(Wed)

KJC-FE09 Program Outline

Session Hour

15:00-17:30

Type Speaker

17:30-19:00

Chair: Sungkyun Park and Kazumi Kato

Opening 09:00-09:20

Chair: Hironori Fujisawa

Plenary talk I 09:20-10:00 Plenary Sang-Wook Cheong

Multiferroics

Coffee break 10:55-11:10

Nano-structured

ferroelectrics

Lunch break 12:15-13:30

Ferroelectric thin

films

Coffee break 15:00-15:15

Lead-free

piezoelectrics

10:00-10:25 Invited Chan-Ho Yang

10:25-10:40 Contributed Shigeo Mori

10:40-10:55 Contributed Ran Hee Sin

Chair: Yoon Hwae Hwang

11:10-11:35 Invited Minoru Osada

11:35-12:00 Invited Suck Won Hong

12:00-12:15 Contributed Kazumi Kato

Chair: Norifumi Fujimura

13:30-13:55 Invited Cheolmin Park

13:55-14:20 Invited Tatsuya Shimoda

14:20-14:45 Invited Tae Won Noh

14:45-15:00 Contributed Min Hyuk Park

Chair: Cheol Seong Hwang

15:15-15:40 Invited Hiroshi Funakubo

15:40-16:05 Invited Jae-Shin Lee

16:05-16:30 Invited Seiji Yamazoe

16:30-16:45 Contributed John G. Fisher

16:45-17:00 Contributed Ken-ichi Kakimoto

Chair: Hiroki Taniguchi and Sang Don Bu

Poster session I 17:00-18:30

Dinner 18:30-20:00


August 9

(Thu)

August 10

(Fri)

KJC-FE09 Program Outline

Session Hour Type Speaker

Chair: Yuji Noguchi

Applications

Coffee break 10:15-10:30

Poster session II 10:30-12:00

09:00-09:25 Invited Masanori Ueda

09:25-09:50 Invited Soon-Gil Yoon

09:50-10:15 Invited Yukihiro Kaneko

Chair: Jae-Hyeon Ko and Kenji Tsuda

Lunch break 12:00-13:30

Chair: Jaichan Lee

Plenary talk II 13:30-14:10 Plenary Yoshiaki Uesu

Superlattices

Photo time 15:00-15:10

Excursion 15:10-18:00

Break 18:00-18:30

Banquet 18:30-21:00

Ferroelectric phase

transitions

14:10-14:35 Invited Ji Won Seo

14:35-15:00 Invited Ji Young Jo

Chair: Chikako Moriyoshi

09:00-09:25 Invited Hiroki Taniguchi

09:25-09:50 Invited Jae-Hyeon Ko

09:50-10:15 Invited Kenji Tsuda

Domain dynamics 10:15-10:40 Invited Yukio Sato

Coffee break 10:40-10:55

Ceramics and nano

particles

Closing 12:00-12:10

Chair: Tae Kwon Song

10:55-11:20 Invited Tae-Sik Yoon

11:20-11:45 Invited Muneyasu Suzuki

11:45-12:00 Contributed Ali Hussain


7 th Aug. (Tue)

15:00 ~ 17:00

17:30 ~ 19:00

8 th Aug. (Wed)

Program of KJC-FE09

Registration and Dormitory allocation

(1F, International Building)

Welcome Reception

(Room 411, 4F, International Building)

(Session Chair : Sungkyun Park & Kazumi Kato)

09:00 ~ 09:20 Opening (Room 101, 1F, International Building)

09:20 ~ 10:00

Plenary

PL-1 Sang-Wook Cheong (Rutgers University)

Multiferroic vortex network with Z2×Z3 symmetry

(Session Chair : Hironori Fujisawa)

Multiferroics (Session Chair : Hironori Fujisawa)

I-1 Chan-Ho Yang (KAIST)

10:00 ~ 10:25 Concurrent transition of magnetic and ferroelectric order near room

temperature

10:25 ~ 10:40

10:40 ~ 10:55

10:55 ~ 11:10 Coffee break

C-1 S. Mori (Osaka Prefecture University)

Charge ordering phenomena in YFe2O4

C-2 Ran Hee Shin (Ewha Womans University)

Ferroelectric polarization driven by divalent ion-substitution into

epitaxial gallium iron oxide thin films

Nano-structured ferroelectrics (Session Chair : Yoon Hwae Hwang)

11:10 ~ 11:35

11:35 ~ 12:00

12:00 ~ 12:15

12:15 ~ 13:30 Lunch break

I-2 Minoru Osada (National Institute for Materials Science)

Two-Dimensional Oxide Nanosheets: New Solution to Nanodielectronics

I-3 Suck Won Hong (Pusan National. University)

Two-faced periodic arrays of ZnO nanorods based on flexible grapheneplastic

substrate for energy harvesting

C-3 Kazumi Kato (National Institute of Advanced Industrial Science and Technology)

Capabilities of BaTiO3 and SrTiO3 Nanocube Self-Assemblies


8 th Aug. (Wed)

Ferroelectric thin films (Session Chair : Norifumi Fujimura)

13:30 ~ 13:55

13:55 ~ 14:20

14:20 ~ 14:45

14:45 ~ 15:00

15:00 ~ 15:15 Coffee break

I-4 Cheol Min Park (Yonsei University)

Controlled hierarchical nanostructures of thin ferroelectric polymer films

for non-volatile memory applications

I-5 Tatsuya Shimoda (Japan Advanced Institute of Science and Technology)

Research topics about solution derived PZT

I-6 Tae Won Noh (Seoul National University)

Tuning ferroelectric properties of epitaxial oxide thin films

C-4 Min Hyuk Park (Seoul National University)

Examination on the ferroelectricity in HfxZr1-xO2 thin film

Lead-free piezoelectric (Session Chair : Cheol Seong Hwang)

15:15 ~ 15:40

15:40 ~ 16:05

16:05 ~ 16:30

16:30 ~ 16:45

16:45 ~ 17:00

I-7 Hiroshi Funakubo (Tokyo Institute of Technology)

Low temperature synthesis of epitaxial and fiber-textured (K,Na)NbO3

thick films grown by hydrothermal method

I-8 Jae-Shin Lee (University of Ulsan)

Possible mechanism of giant strain in BNT-based lead-free ceramics

I-9 Seiji Yamazoe (The University of Tokyo)

Crystallographic and domain structures of ferroelectric (Li,Na)NbO3

films fabricated by a pulsed laser deposition

C-5 John G. Fisher (Chonnam National University)

Sintering of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead–free piezoelectric ceramics

C-6 Ken-ichi Kakimoto (Nagoya Institute of Technology)

Interfacial reactions for Co-fired Ni-(Na,K)NbO3 piezoceramics

(Session Chair : Hiroki Taniguchi & Sang Don Bu)

17:00 ~ 18:30 Poster sesstion I (Gallery, 2F, International Building)

18:30 ~ 20:00 Dinner


9 th Aug. (Thu)

Applications (Session Chair : Yuji Noguchi)

I-10 Masanori Ueda (TAIYO YUDEN Co., Ltd.)

09:00 ~ 09:25 Radio-frequency surface acoustic and bulk acoustic wave devices with

high performances and unique structures

I-11 Soon-Gil Yoon (Chungnam National University)

09:25 ~ 09:50 Realization of transparent and flexible capacitors using reliable graphene

electrode

I-12 Yukihiro Kaneko (Panasonic Corporation)

09:50 ~ 10:15 Recent progress of ferroelectric-gate field-effect transistor based on an

oxide heterostructure

10:15 ~ 10:30 Coffee break

(Session Chair :Jae-Hyeon Ko & Kenji Tsuda)

10:30 ~ 12:00 Poster session II (Gallery, 2F, International Building)

12:00 ~ 13:30 Lunch break

13:30 ~ 14:10

Plenary

PL-2 Yoshiaki Uesu (Waseda University)

SHG microscope revisited

(Session Chair : Jaichan Lee)

Superlattices (Session Chair : Jaichan Lee)

I-13 Ji Won Seo (Sungkyunkwan University)

14:10 ~ 14:35 Ferroelectricity and magnetoelectric coupling in superlattices composed

of non-ferroic components

14:35 ~ 15:00

15:00 ~ 15:10 Photo time

15:10 ~ 18:00 Excursion

18:00 ~ 18:30 Break

18:30 ~ 21:00 Banquet

I-14 Ji Young Jo (Gwangju Institute of Science and Technology)

In-situ X-ray nanodiffraction of ferroelectric heterostructures


10 th Aug. (Fri)

Ferroelectric phase transitions (Session Chair : Chikako Moriyoshi)

09:00 ~ 09:25

I-15 Hiroki Taniguchi (Tokyo Institute of Technology)

Effect of Ca-substitution on the ferroelectricity in CdTiO3

I-16 Jae-Hyeon Ko (Hallym University)

09:25 ~ 09:50 Phase transition behaviors of PbZr1-xTixO3 single crystals as revealed by

elastic anomalies and central peaks

I-17 Kenji Tsuda (Tohoku University)

09:50 ~ 10:15 Study of local structural fluctuations in ferroelectric BaTiO3 using

convergent-beam electron diffraction

Domain dynamics (Session Chair : Chikako Moriyoshi)

I-18 Yukio Sato (The University of Tokyo)

10:15 ~ 10:40 Domain response by electric fields in PMN-PT: An in-situ transmission

electron microscopy study

10:40 ~ 10:55 Coffee break

Ceramics and nanoparticles (Session Chair :Tae Kwon Song)

10:55 ~ 11:20

11:20 ~ 11:45

11:45 ~ 12:00

12:00 ~ 12:10 Closing

I-19 Tae-Sik Yoon (Myongji University)

Resistive switching characteristics of metal-oxide nanoparticle assembly

I-20 Muneyasu Suzuki (National Institute of Advanced Industrial Science

and Technology)

Enhanced ferroelectric properties of bismuth layer-structured

ferroelectric thick films obtained by aerosol deposition method

C-7 A.Hussain (Changwon National University)

Fabrication of lead-free textured (Na0.53K0.47)(Nb0.55Ta0.45)O3 ceramics by

reactive templated grain growth using NaNbO3 templates


Poster Session I (August 8, 17:00~18:30)

Number Presenter Title

P-1 Seong Su Jeong

Increasing torque of one touch point ultrasonic linear motor by using multilayer

ceramics

P-2 Sung Sik Won Photocurrent behaviours of Pt/BNT/Pt and Pt/NKBiT/Pt capacitors

P-3 Won Seok Woo

P-4 Sang-Joon Park

Photovoltaic effect of (Na0.82K 0.18) 0.5Bi 4.5Ti 4O 15 thin film with Pt and ITO top

electrodes

Control of oxygen vacancies by plasma enhanced atomic layer deposition (PEALD) of

TiO 2 for memristors

P-5 Seung Eon Moon Piezoelectric energy scavenger based on PZT LTCC cantilever

P-6 Byung Kil Yun Lead-free alkaline niobates nanostructures for piezoelectric nanogenerators

P-7 Yu Jin Kim Transient negative capacitance in domain wall of ferroelectric thin films

P-8 Shotaro Ishikawa

P-9 Kohei Tsuchida

P-10 Yeong Jae Shin

P-11 Jung Min Park

P-12 Sang Mo Yang

Enhanced dielectric and piezoelectric properties of BaTiO3-based single crystals by

defect-polarization control

Influence of 60 o domain structure on orthorhombic niobate-based piezoelectric

property

Nanoscale visualization of domain wall pinning process as the origin of polarization

fatigue

Preparation of Epitaxial BiFeO3 Thin Films on La-SrTiO 3 Substrate by Magnetic-

Field-Assisted Pulsed Laser Deposition

Equilateral triangle closure domains in (111)-oriented epitaxial PbZr0.35Ti 0.65O 3 thin

films

P-13 Han Joon Kim Effect of Composition on the ferroelectric properties of Hf xZr 1-xO 2 thin film

P-14 H. I. Choi Phase effect of the polycrystalline BiFeO 3 thin film by puled laser deposition

P-15 Myang Hwan Lee The role of defect-dipole in BiFeO 3 thin films

P-16 Byung Chul Jeon Flexoelectric Reversal of Polarization in Epitaxial BiFeO 3 Films

P-17 Hyeon Jun Lee Morphology studies of poly(vinylidene fluoride-trifluoroethylene) copolymer films

P-18 Song A Chae

P-19 Sung Min Seo

Measurement of transverse piezoelectric coefficient in the of Bi0.5(Na 0.82K 0.18) 0.5TiO 3

lead-free films

Electrical Properties of Compositionally Modulated Ferroelectric Pb(Zr,Ti)O3

Multilayer Films

P-20 Chang Jo Han Studies on photovoltaic effect of PZT thin film capacitors depending on Zr/Ti ratio

P-21 Jin Kyu Han

P-22 J.W. Kim

P-23 T. Nakao

P-24 Yu Yamamoto

P-25 Yoshiki Yachi

Effects of Concentration of Multi-walled Carbon Nanotube (MWCNT) on Electrical

Properties of MWCNT�Pb(Zr0.52Ti 0.48)O 3 Composite Films

Structure and electrical properties of Ba(Zrx,Ti1-x)O3 thin films by reactive sputtering

method using metallic target

Fabrication of Orientated (Na0.5K 0.5)NbO 3-BaZrO 3-(Bi 0.5Li 0.5)TiO 3 Thin Films on

LaNiO3/SiO 2/Si Substrates by Pulsed Laser Deposition

(Ag,Li)NbO3 thin films fabricated on (001), (110), and (111)SrTiO3 substrates by

pulsed laser deposition

The effect of crystallization process of P(VDF/TrFE) thin film on the ferroelectric

properties


Number Presenter Title

P-26 K.Wakazono Effects of La substitution for BiFeO 3 epitaxial thin films

P-27 Thi Hinh Dinh

P-28 J. S. Kim

Phase transition behaviors in La-doped Bi1/2(Na 0.82K 0.18) 1/2TiO 3 lead-free piezoelectric

ceramics

Low Frequency Dielectric Dispersion and Conduction Behaviors of BaTiO3 modified

Na0.5Bi 0.5TiO 3 Ferroelectric Ceramics

P-29 Yuhji Tsujimi Low Frequency Optical Phonons in SrTiO 3 under Uniaxial Stress

P-30 Makoto Iwata Temperature-Field Phase Diagrams in Pb(Zn 1/3Nb 2/3)O 3-8%PbTiO 3

P-31 Kazuaki Taji

Charge density study of BiFeO3-PbTiO 3 solid solution system with large tetragonal

lattice distortion

P-32 Mayuko Ogawa Electric-field-induced phase transition of BaTiO 3-based ceramics

P-33 Shoichi Takeda

P-34 Yuto Fujita

P-35 Jae-Hyeon Ko

Structural characteristics of Ca-substituted BaTiO3 in cubic phase by high energy

synchrotron radiation powder diffraction

Nonpolar Soft Optic Phonon of Cubic-rhombohedral Phase Transition of LaAlO3

Studied by Inelastic Light Scattering

Raman and Brillouin scattering studies on lead-free piezoelectric Bi0.5(Na 0.78K 0.22) 0.5xTiO3

ceramics with A-site vacancies

P-36 Ahmed I. Ali Electric and Dielectric Properties of reduced La 0.01Ba 0.99TiO 3

P-37 Hae Jin Seog

P-38 Ryo Kishimoto

P-39 Masashi Igawa

High piezoelectric coefficient of lead-free KNN-based thin films for MEMS

application

Fabrication and Characterization of Inorganic Organic Composites Using

Ferroelectric Nanoplates

Evaluation of switching charge density of PbTiO3 nanoislands by atomic force

microscopy

P-40 Dong Jin Yoon Magnetoelectric Properties of CuFe 2O 4/BaTiO 3 Bi-layer Thin Films

P-41 H. J. Kim

P-42 J. W. Kim

P-43 R. H. Shin

Electrical properties of (Bi0.9A 0.1)(Fe 0.975Cr 0.025)O 3 (A=Ho, Tb and Sm) thin films

prepared by chemical solution deposition

Analysis for crystal structure of rare-earth substituted BiFe0.975Zn 0.025O 3-δ thin films

and their electrical properties

Epitaxial growth of PbVO 3 thin films with a large tetragonality factor and their

polarization reversal at nano-scale

P-44 Dalhyun Do The effects of Mn contents on electrical properties of BiFeO 3

P-45 Jaehong Jeong Spin waves measurement of room-temperature multiferroic BiFeO 3

P-46 K. Kobayashi

P-47 H. Kimura

Real-space imaging of ferroelectric and structural antiphase domain walls in

Hexagonal YMnO3

Pressure-induced magnetic and ferroelectric phase transitions in Multiferroic

EuMn2O 5

P-48 Yusuke Takada Preparation of epitaxial BiFeO 3 thin films by RF planar magnetron sputtering


Poster Session II (August 9, 10:30~12:00)

Number Presenter Title

P-49 Chiaki Kobayashi

Fabrication of PZT/ZnO core-shell nanorods with different PZT thicknesses by

MOCVD

P-50 Taekjib Choi Local charge conductions in multiferroic BiFeO 3 nanostructures

P-51 Jong Yeog Son

Intaglio Nanotemplates Based on Atomic Force Microscopy for Ferroelectric

Nanodots

P-52 Hikaru Igawa Terahertz time-domain spectroscopy study of LiNbO 3

P-53 Akitoshi Koreeda Coherent Entropy-Wave Generation in Quantum Paraelectrics

P-54 Haruki Takayama

P-55 A. Yamashita

Brillouin scattering study of liquid-glass transitions in ternary mixture of water,

trehalose and ionic liquid

Structural and dielectric investigation of the charge ordered organic compound α’-

(BEDT-TTF)2IBr2

P-56 Terutoshi Sakakura Orbital Order in YTiO 3 Observed by Super Accurate Synchrotron X-ray Diffraction

P-57

Rizwan Ahmed

Malik

P-58 Jin Su Park

P-59 S.Y.Lim

Large strain response in Nb-modified BNKT-ST lead-free piezoelectric ceramics

Enhanced piezoelectric properties of lead-free (Bi0.5Na 0.5)TiO 3-BaTiO 3 thin films by

pulsed laser deposition

Na excess effects on dielectric and piezoelectric properties of lead free

(Na0.53+xK 0.47)(Nb 0.55Ta 0.45)O 3 ceramics

P-60 J. H. Choi Effect of the Porosity on Templated Grain Growth Behavior in (K,Na)NbO 3 Ceramics

P-61 Amir Ullah

P-62 Jong-Pil Lee

P-63 Ichiro Fujii

P-64 Haruka Okuda

P-65 Tae Hyun Kim

P-66 A. Zaman

P-67 Byeong-Eog Jun

P-68 C.-W. Cho

Low-frequency Impedance Spectroscopy of BiAlO3 modified Bi 0.5(Na 0.75K 0.25) 0.5TiO 3

lead-free piezoelectric ceramics

Ferroelectric and Piezoelectric Properties of Polycrystalline PbTiO3 Film with

Nanograin

Piezoelectric Enhancement of Relaxor-based Lead-free Piezoelectric Ceramics by

Nanodomain Engineering

Piezoelectric Properties of Ternary Pb(Mn1/3Nb 2/3)O 3 PbTiO 3 PbZrO 3 System Solid

Solutions

Acoustic anomalies and central peaks in 0.83Pb(Mg1/3Nb 2/3)O 3–0.17PbTiO 3 single

crystal studied by the micro-Brillouin scattering

Influence of tantalum substitution on dielectric, ferroelectric and field-induced strain

behavior of lead-free 0.99[Bi0.5(Na 0.82K 0.18) 0.5Ti1-xTax)O 3]-0.01LiSbO 3 ceramics

Ferroelectric Properties of Potassium Sodium Niobium Oxides Ceramics with

Tetragonal and Orthorhombic Composite Structures

Composition dependence of relaxor properties of (1-x)K0.5Na 0.5NbO 3 –

xBa0.5Ca 0.5TiO 3 ferroelectric ceramics

P-69 Kouhei Suzuki Raman scattering study of relaxor ferroelectric Pb(Sc 1/2Nb 1/2)O 3 crystals

P-70 Hiroko Yokota

Domain structure observations of PMN-PT using a second harmonic generation

microscope


Number Presenter Title

P-71 K. Kurushima Evidence of the monoclinic phase around the MPB region in PMN-PT

P-72 Shinya Tsukada

Acoustic phonon behavior in (1-x)Pb(Zn1/3Nb 2/3)O 3-xPbTiO 3 relaxor ferroelectrics

studied by Brillouin scattering

P-73 Changhyo Hong Ferroelectric-Relaxor Composites in Bi-Based Lead-Free Ceramics

P-74 Ichiro Fujii

Dielectric and Piezoelectric Enhancement of New Ceramics with Artificial MPB

Engineering

P-75 Seongtak Yoon Electrical Properties of (Sr 0.75,La 0.25)TiO 3 Ultra-thin Films

P-76 Taejun Hwang Transport Properties of Low Dimensional La 0.75Sr 0.25VO 3 Thin Films

P-77 Eisuke Magome

Structural study of gradient lattice distortion in BaTiO3-KNbO 3 composites with

heteroepitaxial interface

P-78 Myoung Pyo Chun Characterization of BN doped BaTiO 3 PTC thermister

P-79 Da Jeong Kim

P-80 Sang Wook Kim

Grain growth and piezoelectric property of (Na 0.545K 0.47)(Nb 0.55Ta 0.45)O 3 with a

sintering aid of Li 2CO 3 and MnO 2 by template grain growth method

Structural analysis of lead free (Bi0.5Na 0.5)TiO 3 base ceramics using Rietveld

refinement method

P-81 Byeong-Eog Jun Lithium doping in the Gallium and Magnesium modified Zinc Oxides

P-82 Kengo Shibata Low-Temperature Synthesis of (Na,K)NbO 3 by Dissolution-Precipitation Method

P-83 Masahiko Bekki O 2 Annealing Effect on KF-Substituted BaTiO 3 Ceramics

P-84 Ken Yanai

P-85 Won-June Kim

P-86 Hye-Jung Kim

Crystal structures and polarization/piezoelectric properties of ferroelectric

(Bi0.5K 0.5)TiO 3–(Bi 0.5Na 0.5)TiO 3 Single Crystals

Density functional theory study of paraelectric-ferroelectric phase transition of

polyvinylidene difluoride

First-principles study of piezoelectric and dielectric properties of a graphene-based

dipolar layer

P-87 Md. Noor-A-Alam Piezoelectricity and elasticity of hydrogenated boron nitride monolayer

P-88

Gantsooj

Amarsanaa

P-89 P. V. Ong

Atomic displacement of Tetragonal PbTiO3 with different high electric field directions

Energy-band alignment and orbital-selective charge transfer at oxygen-deficient

LaAlO 3/SrTiO 3(001) interfaces

P-90 Hiroki Moriwake Ferroelectric phase transition of AgNbO 3: a first-principles study


Oral Presentation

(Room101, 1F, International Building)


Plenary

Multiferroic vortex network with Z2×Z3 symmetry

PL-1

09:20 ~ 10:00, August 8

S-W. Cheong

Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854, USA

and Laboratory for Pohang Emergent Materials, Postech, Pohang, Korea

The fascinating concept of topological defects permeates ubiquitously our understanding

of the early-stage universe, hurricanes, quantum matters such as superfluids and

superconductors, and also technological materials such as liquid crystals and magnets. Largescale

spatial configurations of these topological defects have been investigated only in a

limited degree. Exceptions include the cases of supercurrent vortices or liquid crystals, but

they tend to exhibit either trivial or rather-irregular configurations.

Hexagonal REMnO3 (RE= rare earths) with RE=Ho-Lu, Y, and Sc, is an improper

ferroelectric where the size mismatch between RE and Mn induces a trimerization-type

structural phase transition, and this structural transition leads to three structural domains, each

of which can support two directions of ferroelectric polarization. We reported that domains in

h-REMnO3 meet in cloverleaf arrangements that cycle through all six domain configurations,

Occurring in pairs, the cloverleafs can be viewed as vortices and antivortices, in which the

cycle of domain configurations is reversed. Vortices and antivortices are topological defects:

even in a strong electric field they won’t annihilate. These ferroelectric vortices/antivortices

are found to be associated with intriguing magnetism.

Recently we have found intriguing, but seemingly irregular configurations of a zoo of

multiferroic vortices and antivortices in h-REMnO3. These configurations can be neatly

analyzed in terms of graph theory and this graph theoretical analysis reflects the nature of

self-organized criticality in complexity phenomena as well as the condensation and eventual

annihilation processes of topological vortex-antivortex pairs. These numerous multiferroic

vortices/antivortices can be understood as an arrested Kosterlitz-Thouless phase.

In addition, we have discovered the emergence of Z2×Z3 symmetry in the seeminglyrandom

network of numerous ferroelectric vortices, and electric poling or self-poling due to a

surface charge boundary condition induces global topological condensation through breaking

of the Z2 part of the Z2×Z3 symmetry. The opposite process of restoring the Z2 symmetry can

be considered as topological evaporation. Our discovery opens new avenues for exploring

non-trivial topology of large-scale domain configurations in complex materials, playing an

essential role in macroscopic physical properties.


Plenary

SHG microscope revisited

Yoshiaki Uesu

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

* E-mail address of the corresponding author : uesu93@waseda.jp

PL-2

13:30 ~ 14:10, August 9

On the occasion of the 6th Korea-Japan Conference of Ferroelectrics in Sendai, I talked

about our optical second-harmonic generation (SHG) microscope strengthening upon possible

applications to ferroelectric 180°domain structure observations.[1] Since that time, exciting

progress has been made in this field as a unique tool of mesoscopic structures in multiferroic

crystals[2], thin films[3], and nondestructive and three-dimensional (3D) observations of

domain structures.[4-7]

On reflecting the recent progress, following subjects are described:

(1) Intrinsic issue of the visibility of 3D observations related with the momentum transfer

mismatch between the fundamental and SH photons.[4]

(2) Observation and characterization of periodically poled domain (PPD) structures in quasiphase

matching (QPM) devices of wavelength converter with high conversion efficiency.

[4-6]

(3) Observations of the PPD structure in muscle fibers. Can a muscle fiber be QPM?

(4) Domain structure analyses of relaxer/ferroelectric solid solutions at the morphotropic

phase boundary.[7]

References

1. Y. Uesu, H. Yokota, S. Kawada and N. Kato, J. Korean Phys. Soc. 51, 804 (2007).

2. M. Fiebig, V. V. Pavlov, and R. V. Pisarev, J. Opt. Soc. Am. B 22, 96-118 (2005).

3. S. Denev, T. Lummen, E. Barnes, A. Kumar, and V. Gopalan, J. Amer. Ceram. Soc, 1-29

(2011).

4. J. Kaneshiro, S. Kawado, H. Yokota, Y. Uesu, and T. Fukui, J. Appl. Phys. 104, 054112

(2008).

5. Y. Uesu, H. Yokota, S. Kawado, J. Kaneshiro, S. Kurimura, and N. Kato, Appl. Phys. Lett.

91, 182904 (2007).

6. J. Kaneshiro, Y. Uesu, and T. Fukui, J. Opt. Soc. Am. B 27, 888 (2010).

7. J. Kaneshiro and Y. Uesu, Phys. Rev. B 82, 184116 (2010).


Invited

I- 1

10:00 ~ 10:25, August 8

Concurrent transition of magnetic and ferroelectric order near room

temperature

Chan-Ho Yang 1,2*

1 Department of Physics, KAIST, Daejeon 305-701, Korea

2 KAIST Institute for the NanoCentury, Daejeon 305-701, Korea

* E-mail address of the corresponding author : chyang@kaist.ac.kr

In the talk, we will focus on a highly-elongated multiferroic BiFeO3 thin film, which has

been newly discovered to be a quasi-layered phase stabilized through a misfit strain.[1] We

will discuss underlying physics inherent in the quasi-layered structure and introduce our

recent progress on the physical properties of the quasi-layered BiFeO3 films.[2] It will be

presented that the magnetic Néel temperature of multiferroic BiFeO3 compound is unusually

suppressed to near room temperature by heteroepitaxial misfit strain. Remarkably the

ferroelectric state undergoes a first-order transition to another ferroelectric state

simultaneously at the magnetic transition temperature. Our findings provide a unique example

to show concurrent magnetic and ferroelectric transition at the same temperature among

proper ferroelectrics. Moreover, we control the multiferroic transition by A-site substitutions.

The transition temperature can be varied systematically from ~350 K to ~100 K as results of

chemical pressure or/and bismuth dilution effect. Finally, we will introduce our strategy to

realize electrical switching of the magnetic state at room temperature based on the compounds.

[1] R. J. Zeches et al., Science 326, 977-980 (2009).

[2] K. T. Ko et al., Nature Communications 2, 567 (2011).


Invited

I- 2

11:10 ~ 11:35, August 8

Two-Dimensional Oxide Nanosheets: New Solution to Nanodielectronics

Minoru Osada 1,2* and Takayoshi Sasaki 1,2

1 International Center for Materials Nanoarchitectnics (MANA), National Institute for

Materials Science (NIMS), Tsukuba 305-0044, Japan

2 CREST, JST, Kawaguchi 332-0012, Japan

* E-mail address of the corresponding author : osada.minoru@nims.go.jp

The 2010 Noble prize in physics for the work on graphene emphasizes the importance of

new paradigm of two-dimensional (2D) crystalline materials research. Due to the excitements

caused by graphene, other 2D materials have increasingly attracted fundamental research

interest as they could open up unprecedented physical properties that cannot be attained in

graphene. Here, we present the progress made in the properties of 2D oxide nanosheets,

highlighting emerging functionalities in dielectronic applications [1, 2]. Titania- or

perovskite-based nanosheets exhibit superior high-k performance (εr = 100 – 320) even at a

few-nm thicknesses, which is an essential requirement for next-generation electronics [3].

Additionally, nanosheet-based multilayer capacitors exceed textbook limits, opening a route

to new capacitor devices. One more potentially interesting concept using 2D oxide nanosheets

is designing superstructured nanohybrids such as field-effect transistors [1], spinelectronic

devices [4], and artificial ferroelectric materials [5]. With these unique aspects, 2D oxide

nanosheets will become an important research target in the form of “ceramic graphene” or

“oxide graphene”.

[1] M. Osada and T. Sasaki, J. Mater. Chem. 19, 2503 (2009) [Review].

[2] M. Osada and T. Sasaki, Adv. Mater. 24, 209 (2012) [Review].

[3] M. Osada et al., Adv. Mater. 18, 1223 (2006); ACS Nano 3, 1097 (2009); ACS Nano 4,

4995 (2010); ACS Nano 4, 5225 (2010); Adv. Funct. Mater. 21, 3482 (2011).

[4] M. Osada et al., Adv. Mater. 18, 295 (2006); PRB 73, 153301 (2006); APL 92, 253110

(2008); Chem. Mater. 21, 4366 (2009); ACS Nano 5, 6871 (2011).

[5] B. W. Li, M. Osada et al., ACS Nano 4, 6673 (2010); Jpn. J. Appl. Phys. 50, 09NA10

(2011).


Invited

I- 3

11:35 ~ 12:00, August 8

Two-faced periodic arrays of ZnO nanorods based on flexible grapheneplastic

substrate for energy harvesting

Se-Jeong Park 1 , Yoon-Hwae Hwang 1,2 and Suck Won Hong 1,2

1 Dept. of Nano Fusion Technology, Pusan National. University, Miryang, 627-709, Korea

2 Dept. of Nanomaterials Engineering, Pusan National. University, Miryang, 627-709, Korea

* E-mail address of the corresponding author: swhong@pusan.ac.kr

Wearable and flexible energy harvesting systems could be usefully applied to various

types, such as outdoor clothing, recharge for mobile devices or artificial organs, moving and

bending our joints and so on. Yet, the power should approach as same value as one

commercial battery to use the system in our daily life, so the most attractive point is how

much we should get energy from energy harvesting system. To increase the harvesting

efficiency rate, we present a simple and robust energy harvesting system of the two-faced

periodic arrays of ZnO nanorods based on graphene and polyethylene terephthalate (PET)

substrate via pulsed laser deposition method and low-temperature hydrothermal growth. The

two-faced periodic arrays of ZnO nanorods reinforce the rate of energy harvesting whenever

bending the system back and forth. Graphene-PET substrate gives excellent flexibility and the

graphene sheets are inserted into the two-faced periodic arrays of ZnO nanorods and on the

bottom of them due to its ideal monolayer with phi electrons. The harvesting efficiency with

the two-faced system shows more enhanced than a system with the one-faced.


Invited

I- 4

13:30 ~ 13:55, August 8

Controlled Hierarchical Nanostructures of Thin Ferroelectric Polymer

Films for Non-volatile Memory Applications

Cheolmin Park * , Seok Ju Kang, Youn Jung Park, Insung Bae

and Richard Hahnkee Kim

Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea

* E-mail address of the corresponding author : cmpark@yonsei.ac.kr

Information storage devices of ferroelectric polymers such as poly(vinylidene fluoride)

(PVDF) and its copolymers with trifluoroethylene (TrFE) have been of a great attention in

virtue of mainly low cost solution processibility based on spin coating for their potential use

in non-volatile memory technology, one of the most essential technologies in the current

mobile industry. The basic ferroelectric polymer storage element is metal/ferroelectric

polymer/metal (MFM) capacitor in which a ferroelectric polymer thin film sandwiched

between arrays of metal electrodes that makes possible electrical charge signaling across the

structure. More recently ferroelectric thin films have been applied as gate dielectric to form a

Ferroelectric Field-Effect Transistor (FeFET) device structure. The polarization state of the

ferroelectric gate set by the polarity of the writing gate voltage controls the electrical

conductance of the channel between source and drain electrode. There have been many efforts

to enhance FeFET memory performance such as nondestructive readout capability, scalability,

flexibility, printing capability, endurance, and materials design including electrodes,

ferroelectric and insulating layers. In this presentation, we demonstrate various novel routes to

fabricate high performance nonvolatile FeFETs. For instance, using a hybrid interlayer

consisting of PVDF-TrFE that is confined into nanoscopic trenches of an organosilicate (OS,

dielectric), operating voltages for the devices are as low as 8 V. By confining the ferroelectric

polymer into 30 nm thick OS trenches of 30 nm in width and 50 nm in periodicity, we could

achieve a thin and structurally dense ferroelectric layer with crystal orientation effective for

facile polarization switching. The low gate leakage of our PVDFTrFE/OS hybrid layer

facilitates the fabrication of a bottom gate FeFET with a single crystalline TIPS-PEN channel

that operates at such a low voltage with ON/OFF ratios larger than 10 2 , and data retention of

approximately 2 h under ambient conditions. Furthermore, we present a highly reliable and

mechanically flexible multilevel Fe-FET with a thin PVDF-TrFE insulator. Our device is

based on multileveled non-volatile drain current states of a polymeric semiconductor

precisely controlled by a ferroelectric insulator. Our multilevel Fe-FET fabricated on a

polymer substrate provided mechanical flexibility in which the characteristic 4-level reliable

switching was also realized with more than 1,000 bending cycles at a bending radius of 5.8

mm.


Invited

Research Topics about solution derived PZT

I- 5

13:55 ~ 14:20, August 8

Tatsuya Shimoda 1,2*,3

1 Green Devices Research Center and 2 School of Materials Science, Japan Advanced Institute

of Science and Technology, 1-1Asahidai, Nomi, Ishikawa 923-1245, Japan

3 Japan Science and Technology Agency, ERATO, Shimoda Nano Liquid Process Project, 2-

5-3 Asahidai, Nomi, Ishikawa 923-1211, Japan

* E-mail address of the corresponding author : tshimoda@jaist.ac.jp

I will introduce research topics related solution based PZT, which have been conducted

in JST-ERATO Shimoda nano-liquid process project from October 2006 to March 2012.

ERATO, Exploratory Research for Advanced Technology, is one of major research funding

programs provided by Japan Science and Technology Agency (JST).

The research objective of ERATO Shimoda project is to create a new method to print

nano-sized authentic electronics devices and circuits using functional solutions. As one of the

target devices, we chose FGT (Ferroelectric Gate Transistor). As for a structure of FGT, a

bottom gate one, in which ITO and PZT were a channel and gate insulator layer, respectively,

was adopted. The polarization of PZT is so large that it can completely deplete the ITO

channel. So, this structure can be a transistor with memory function caused by the hysteresis

of PZT. Three topics will be introduced: (1) low temperature formation of PZT by using

chemical solution deposition (CSD) methods, (2) totally solution processed FGT and (3) a

NAND memory constructed by solution processed FGTs.

(1) low temperature formation of PZT We found a novel low-temperature crystallization

path where the perovskite structure were directly formed at 400 -500 degree C without

passing through pyrochlore formation. This is caused by the reaction that reductive agents

such as monoethanolamin or curbon reduce Pb 2+ to Pb 0 at 200-300 degree C so that there is

no way for pyrochlore phase can be formed due to the shortage of Pb element.

(2) totally solution processed FGT Prior to direct printing of FGT, it should be fabricated

only by using solution materials . By adopting LaNiO for a gate and ITO both for a channel

and source/drain electrodes, a FGT with high performance was developed. Its all layers were

constructed by metal-oxide materials which were made from solution precursors.

(3) NAND memory A new circuit design was invented to make a NAND circuit using

FGT as a memory element. The developed NAND circuit has dual FGT cells, one of which is

for a memory while the other is a pass transistor. Non-destructive writing, reading and erasing

operations were demonstrated without any disturbance.


Invited

I- 6

14:20 ~ 14:45, August 8

Tuning Ferroelectric Properties of Epitaxial Oxide Thin Films

Tae Won Noh 1* , Daesu Lee 1 , Sang Mo Yang 1 , Tae Heon Kim 1 , Byung Chul Jeon 1 ,

Young Jae Shin 1 and Jong-Gul Yoon 2

1 ReCFI, Department of Physics and Astronomy, Seoul Nat’l Univ., Seoul 151-747, Korea

2 Dept. of Physics, Univ. of Suwon, Hwaseong, Gyunggi-do 445-743, Korea

* E-mail address of the corresponding author : twnoh@snu.ac.kr

Ferroelectric materials possess a spontaneous polarization that can be electrically

switchable. Thus ferroelectrics have opened a possibility of electrical control of their

functionality. They have been used for wide applications, such as non-volatile memory and

sensor. In addition, they have shown various interesting physical properties, stimulating

scientific interest by many researchers.

Despite extensive studies, many aspects on ferroelectrics remain untouched. In this

presentation, we will report systematic ways to tune ferroelectric properties using a couple of

methods: namely (1) “flexoelectricity” and (2) “displacement currents.” We will show that

these approaches can enhance the application potential of ferroelectrics significantly, as well

as allow their novel physical phenomena. Firstly, we will show that a giant and controllable

flexoelectric effect can allow a novel opportunity to tune the physical properties of

ferroelectric epitaxial thin films, such as domain configurations and polarization switching

behaviors [1]. Secondly, using our concept of deterministic polarization control, we will

demonstrate the multilevel polarization states in real ferroelectric thin-film systems, formed

by controlling displacement currents [2]. These methods illustrate the potential of controlling

ferroelectric domain growth as well as scaling up the storage density of FeRAM.

[1] D. Lee et al., Phys. Rev. Lett. 107, 057602 (2011)

[2] D. Lee et al., Adv. Mater. 24, 402 (2012)


Invited

I- 7

15:15 ~ 15:40, August 8

Low temperature synthesis of epitaxial and fiber-textured (K, Na)NbO3

thick films grown by hydrothermal Method

Hiroshi Funakubo 1* , Takahisa Shiraishi 1 , Mutsuo Ishikawa 2 and Minoru Kurosawa 1

1 Interdisciplinary Graduate school of Science & Engineering, Tokyo Institute of Technology,

4259-J2-43, Nagatsuta-cho, Midori-ku, Yokohama, 226-8502, Japan

2 Department of Clinical Engineering Faculty of Biomedical Engineering, Toin University of

Yokohama, 1614 Kurogane-cho, Aoba-ku, Yokohama, 225-8503, Japan

* E-mail address of the corresponding author : funakubo@iem.titech.ac.jp

Low temperature growth of functional oxide is an very important issues for the application

compatible to the organic electronics. Hydrothermal method has been recognized as the potantial

preparation method for growing epitaxal crystalline films even below 300 o C as well as their high

growth rate. Our groups grew KNbO3 films grown at 240 o C by hydrothermal method using KOH and

Nb2O5 as source materials. Film thickness increased with reaction time up to 3 h, however decreased

for longer reaction times. A 16-�m-thick epitaxially grown KNbO3 films with (100)pc orientation

were successfully grown on (100)cSrRuO3//(100)SrTiO3 substrates for 3 h. The relative dielectric

constant and dielectric loss at 100 kHz were 415 and 8%, respectively. Clear hysteresis loops

originating from ferroelectricity were observed and the remanent polarization was 20 �C/cm 2 at the

maximum applied electric field of 220 kV/cm. The effective longitudinal piezoelectric constant

obtained using a Laser Doppler velocimeter, was 86 pm/V. Film thickness can be extened to beyond

100 �m. This process can be also used as the process to obtain bulk materials with three-

dimentionally orientation control. In addition, we demostrated the preparation films of KNbO3-

NaNbO3 solid solution on flexible matel foiles that is useful for the energy hervasting applications.

1) M.Ishikawa et al., Mater. Res. Soc. Symp. Proc., 1139 (2009) 1139-GG03-52.

2) M.Ishikawa et al., Jpn. J. Appl.Phys. , 48 (2009) 09KA14-1-4.

3) M.Ishikawa et al., Jpn. J.Appl. Phys., 49 (2010) 07HF01-1-4.

4) H. Einishi et al., Key Eng. Mater., 485 (2011) 199-202.

5) T. Shiraishi et al., Jpn. J. Appl. Phys., 50 (2011) 09ND11-1-4.


Invited

I- 8

15:40 ~ 16:05, August 8

Possible mechanism of giant strain in BNT-based lead-free ceramics

Jae-Shin Lee 1* , Hyoung-Su Han 1 , Chang-Won Ahn 2 and Ill Won Kim 2

1 School of Materials Science and Engineering, University of Ulsan, Ulsan 680-749, Korea

2 Department of Physics, University of Ulsan, Ulsan 680-749, Korea

* E-mail address of the corresponding author : jslee@ulsan.ac.kr

The electric-field-induced strain (EFIS) of impurity doped (Bi,Na)TiO3-(Bi,K)TiO3

(BNKT) ceramics near the morphotropic phase boundary were investigated. The dopants

investigated in this work include Zr, Hf, Sn, Nb, Ta, Y, and Cu. Heterovalent dopants brought

about a phase transition from coexistence of rhombohedral and tetragonal phases to a

nonpolar pseudocubic phase.

The impurity-induced phase transition remarkably enhanced the EFIS of BNKT

ceramics even though their ferroelectric and piezoelectric properties of BNKT ceramics

degraded gradually in terms of the static piezoelectric constant d33, remnant polarization,

coercive field, and piezoelectric coupling coefficient. Dielectric measurements indicated that

doped BNKT ceramics reveal relaxor ferroelectric (RFE) behaviors that are distinct in terms

of diffuse transition points and frequency dependent peaks in dielectric permittivity.

This study discusses underlying mechanisms for doping-induced strain enhancement on

the basis of analyses on their microstructure, crystal structure, dielectric, and piezoelectric

properties. The tolerance factor (t) of BNKT ceramics doped with various impurities was

calculated and correlated with Tm (temperature at which the dielectric constant reaches

maximum) and the depolarization temperature (Td). It was found that with increasing t, the Td

increased while Tm decreased. On the other hand EFIS showed little relationship with the t

while atomic mass of dopant seemed to have a relationship with EFIS. Many impurities such

as Zr, Sn, Ta, and Nb led to a abnormal enhancement in the normalized strain Smax/Emax up to

over 500 pm/V in strain-electric field (S-E) measurements. The maximum strain and Smax/Emax

were 0.43% and 730 pm/V, respectively, when Nb and Li were co-doped into BNKT

ceramics.

In addition, such transition-induced giant strains were experimentally observed when

BNKT was also modified with other ABO3-type perovskites such as LiTaO3, Sr(K,Nb)O3,

BaZrO3, and CaZrO3. It is noted that the tolerance factor of other end member was found to

be important for the FE-RFE phase transition. Based on our recent findings, this paper

discusses the origin of the phase transition induced-giant strain in Bi-perovskites.


Invited

I- 9

16:05 ~ 16:30, August 8

Crystallographic and Domain Structures of Ferroelectric (Li,Na)NbO3

Films Fabricated by a Pulsed Laser Deposition

Seiji Yamazoe*, Akihiro Kohori, Hiroyuki Sakurai and Takahiro Wada

Department of Materials Chemistry, Ryukoku University, Otsu 520-2194, Japan

* E-mail address of the corresponding author : yamazoe@rins.ryukoku.ac.jp

Ferroelectricity and piezoelectricity depend on crystallographic and domain structures.

We have reported that the domain structure could be observed by a laser scanning microscope

(LSM) [1]. A Raman spectroscopy is a powerful tool to analyze the crystal phase [2]. In the

present study, we fabricated ferroelectric NaNbO3 (NN) and (LixNa(1-x))NbO3 (LNN) thin

films with x = 0.05, 0.10 and 0.13 on (001)SrTiO3 (STO) substrate by a pulsed laser

deposition (PLD). The crystallographic structures of the films were analyzed by X-ray

diffraction and Raman spectroscopy and the domain structures were observed by LSM.

NN and LNN (x = 0.05, 0.10, 0.13) films were grown on (001)STO substrate by the PLD.

The SrRuO3 (SRO) bottom electrodes were deposited by the PLD before fabrication of the

NN and LNN films. The crystal phases and the orientation were analyzed by X-ray diffraction

and Raman spectroscopy. The domain structures were observed by LSM. The ferroelectric

properties were recorded by a ferroelectric tester.

The X-ray diffraction patterns show that all the films

had 001 orientation. The Raman spectra clearly showed

that the NN film had antiferroelectric orthorhombic phase,

(Li0.05Na0.95)NbO3 (LNN05) and (Li0.10Na0.90)NbO3

(LNN10) films had ferroelectric orthorhombic phase, and

(Li0.13Na0.87)NbO3 (LNN13) film had a ferroelectric

orthorhombic and ferroelectric rhombohedral mixed

phase. The results were consistent with the observation of

the domain structures by LSM. We found that the crystal

phase and domain structure were drastically changed by

Fig. 1 LSM image of LNN13 after

applying an electric field.

applying an electric field. Figure 1 shows the domain structure of LNN13 after applying an

electric field of 250 kV/cm. We can see that only the domain under the electrode changed.

From the Raman spectra and LSM images, this drastically change is due to not only the phase

transition from ferroelectric orthorhombic and rhombohedral mixed phases to rhombohedral

single phase but also the change of polarization direction. We confirmed that the ferroelectric

properties depend on the change of the crystal and domain structures.

[1] S. Yamazoe et al., Appl. Phys. Lett., 96, 092901 (2011). [2] Y. Shiratori et al, J. Phys.

Chem.C, 111, 18493 (2009).


Invited

I- 10

09:00 ~ 09:25, August 9

Radio – Frequency Surface Acoustic and Bulk Acoustic Wave Devices with

high performances and unique structures

Masanori Ueda 1* , Motoaki Hara 2 , Tsuyoshi Yokoyama 1 , Takeshi Sakashita 1 ,

Masafumi Iwaki 1 , Shinji Taniguchi 1 , Tokihiro Nishihara 1 , Michio Miura 1 ,

Takashi Matsuda 1 and Yoshio Satoh 1

1 TAIYO YUDEN CO.,LTD., 64 Nishiwaki, Okubo-cho, Akashi 674-8555, Japan

2 Graduate School of Engineering, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai

980-8578, Japan

* E-mail address of the corresponding author : maueda@jty.yuden.co.jp

The performances of radio-frequency (RF) surface acoustic wave (SAW) filters and

duplexers have improved markedly, and they are now widely used in the mobile

communication market. RF bulk acoustic resonator (BAW) filters and duplexers based on

film bulk acoustic resonator (FBAR) or solidly mounted resonator (SMR) technologies are

also increasingly used in the market. Requirements such as insertion losses, cut-off

performances, isolations, linearity and so on for filters and duplexers in systems are getting

tighter, therefore new techniques are needed to meet specifications. In this conference, we

will introduce our unique temperature compensated SAW (TC-SAW) and FBAR technologies.

1. TC-SAW

We have developed TC-SAW devices with hybrid substrates constructed of LiTaO3 and

sapphire substrates employing a direct bonding technique at room temperature. A sapphire

substrate can suppress a temperature expansion of LiTaO3 boned to a sapphire because of low

temperature expansion coefficient and high young’s modulus of a sapphire, therefore a

temperature drift of center frequency of a filter was improved. Thanks to good heat radiation

of a sapphire, better power handling capability of a SAW duplexer was also confirmed.

2. FBAR

We have developed air-gap type FBARs, which are applicable not only for S-band but

also for X to Ka-band frequencies. Our proposed air-gap structure is simple and cost-effective.

The air-gap can be formed on the flat substrate using stress control of piezoelectric (AlN) and

metal films (Ru) without using a thick sacrificial layer. Results from both simulations and

experiments demonstrate that a dome-shaped air-gap was formed between the substrate

surface and the bottom electrode, and that an air-gap type FBAR structure with good

performance was possible. Filters and duplexer with good performances using air-gap FBARs

were realized.


Invited

I- 11

09:25 ~ 09:50, August 9

Realization of Transparent and Flexible Capacitors using Reliable

Graphene Electrodes

Sin-Hye Na, Hyun-A Song and Soon-Gil Yoon *

Department of Materials Engineering, Chungnam National University, Daeduk Science Town,

305-764 Daejeon, Korea

* E-mail address of the corresponding author : sgyoon@cnu.ac.kr

Reliable graphenes grown by rapid-thermal pulse chemical vapor deposition (CVD) for

electrode applications were selectively patterned under optimum conditions for argon rf

plasma power and etching time. For the transparent and the flexible capacitors using

Bi2Mg2/3Nb4/3O7 (BMNO) dielectric films grown at room temperature, the graphene top and

bottom electrodes were integrated onto the polymer substrates. The

graphene/BMNO/graphene/Ti/polyethersulfone (PES) capacitors showed typical dielectric

and the leakage properties for capacitors. The adhesion between substrates and the graphene

should be critically considered in order to improve the leakage properties of the capacitors.

Graphene that possessed a high bendability was the predominant candidate for application to

the top and bottom electrodes of the transparent and flexible capacitors.


Invited

I- 12

09:50 ~ 10:15, August 9

Recent Progress of Ferroelectric-gate Field-Effect Transistor

Based on an Oxide Heterostructure

Yukihiro Kaneko 1* , Yu Nishitani 1 , Hiroyuki Tanaka 1 , Michihito Ueda 1 ,

Yoshihisa Kato 2 and Eiji Fujii 1

1 Advanced Technology Research Laboratories, Panasonic Corp., Kyoto 619-0237, Japan

2 Semiconductor Device Development Center, Panasonic Corp., Kyoto 617-8520, Japan

* E-mail address of the corresponding author: kaneko.yukihiro001@jp.panasonic.com

A ferroelectric-gate field-effect transistor (FeFET), which uses ferroelectric material as a

dielectric layer for a metal oxide semiconductor FET, is of great interest for nonvolatile

memory devices. This is because its channel conductance can be switched and memorized

continuously with low power consumption at high speed. However, it is difficult to fabricate a

FeFET which has a good retention property due to the reaction between the ferroelectric and

Si, when a ferroelectric is deposited directly on a Si substrate. We have focused on carrier

conduction in the oxide heterostructure which can eliminate undesirable reaction layer. We

chose an inverted staggered (bottom-gate) thin-film transistor structure as a novel FeFET. We

fabricated a FeFET based on a combinatorial oxide structure consisting of stacked perovskite

oxides with similar lattice parameters: a ferroelectric film of Pb(Zr,Ti)O3 (PZT), a bottom

gate electrode of SrRuO3 (SRO), and a substrate of (100)-sliced SrTiO3 (STO). This

combination enabled the heteroepitaxial growth of a PZT/SRO/STO structure with a

homogeneous crystal orientation, which, in turn, led to well-oriented growth of ZnO on top of

the PZT. This gave rise to a very sharp ZnO/PZT interface. The fabricated FeFET showed

electron gas accumulation and complete depletion switching due to the ferroelectric

polarization reversal. As a result, it showed not only the continuous conductance modulation

with wide range but also a very long retention time that exceeded 3.5 months [1,2]. We can

predict a ten-year data retention in a FeFET. In addition, we revealed that the channel

formation originated from the ferroelectric domain wall movement from the channel edge to

the center [3]. We also succeeded the fabrication of a FeFET on a Si-substrate, of which

electrical property was as same as that on STO [4]. These characteristics are suitable for not

only nonvolatile memory, which consists of NOR- and NAND-type FeFET memory cells

[2,5], but also analog memory applications, such as neural networks [6].

[1] Y. Kato, et. al., Jpn. J. Appl. Phys. 47 (2008) 2719. [2] Y. Kaneko, et. al., IEEE Trans. Electron Devices 58

(2011) 1311. [3] Y. Kaneko, et. al., J. Appl. Phys. 110 (2011) 084106 [4] H. Tanaka, et. al., Jpn. J. Appl. Phys.

47 (2008) 7527. [5] Y. Kaneko, et. al., Jpn. J. Appl. Phys. 48 (2009) 09KA19. [6] M. Ueda, et. al., J. Appl. Phys.

110 (2011) 086104.


Invited

I- 13

14:10 ~ 14:35, August 9

Ferroelectricity and magnetoelectric coupling in superlattices composed of

non-ferroic components

Ji Won Seo 1* and Jaichan Lee 1

1 School of Advanced Materials Science and Engineering, Sungkyunkwan University,

Suwon 440-746, Republic of Korea

* E-mail address of the corresponding author : jiwonseo606@gmail.com

Phase transitions during crystal symmetry changes in ferroic materials are well known to

give rise to their electrical and magnetic properties. Conversely, materials devoid of ferroics

are presumed not to display any macroscopic type of ordering such as ferroelectricity or

ferromagnetism. Recently however, oxide-based heterostructures have exposed a wealth of

phenomena at the boundaries where compounds with different electronic properties meet,

giving unprecedented access to novel properties. Examples include novel metallic, magnetic

and superconducting characteristics in multilayers composed of non-magnetic insulators.

Here, we report the discovery of ferroelectricity and strong magnetoelectric coupling in threecomponent

superlattices consisting of solely non-ferroelectric and anti-ferromagnetic

NdMnO3/SrMnO3/LaMnO3 layers. Ferroelectricity plateau was observed below 40 K and

magnetoelectric coupling was found to result in close to a 200% magnetic modulation of the

electrical polarization. Our results demonstrate a fascinating example of the emergence of

unprecedented physical properties in artificially grown correlated electron oxides structures.


Invited

I- 14

14:35 ~ 15:00, August 9

In-Situ X-Ray Nanodiffraction of Ferroelectric Heterostructures

Ji Young Jo 1* , Pice Chen 2 , Rebecca J. Sichel 2 , Eric M. Dufresne 3 , Matthew Dawber 4 ,

Ho Nyung Lee 5 , Serge M. Nakhmanson 6 and Paul G. Evans 2

1 School of Materials Science and Technology, GIST

2 Department of Materials Science and Technology, University of Wisconsin-Madison

3 Advanced Photon Source, Argonne National Laboratory

4 Department of Physics, Stony Brook University

5 Materials Science and Technology Division, Oak Ridge National Laboratory

6 Materials Science Division, Argonne National Laboratory

* E-mail address of the corresponding author: jyjo@gist.ac.kr

The responses of ferroelectric heterostructures to external electric fields provide

functionalities including electromechanical distortion and switching of remnant polarization

at nanometer scale. Nano-scaled features of ferroelectric heterostructures such as components

of ferroelectric/dielectric superlattices with nanometer-scale repeating units and ferroelectric

domains have been predicted to possess novel electromechanical properties. However,

electromechanical properties of nano-scaled features have not previously been probed

individually due to a lack of in-situ imaging methods. To study the electromechanical

responses arising from the ferroelectric and/or dielectric components, we have performed a

synchrotron X-ray microdiffraction study of a BaTiO3-CaTiO3 and PbTiO3-SrTiO3

superlattices. In our electrimechanical studies, we found intriguing results: (1) both

ferroelectric and dielectric components contribute equally to the overall piezoelectric strain, 1

(2) The time required to reach the maximum strain decreases with increase of the magnitude

of the applied electric field due to the switching of nano-stripe domains, 2 and (3) domains

written by piezoresponse force microscopy exhibit the strain up to 0.1%. 3 In this presentation,

we will discuss details of our recent results.

1 J.Y. Jo et al., Phys. Rev Lett. 104, 207601 (2010)

2 J.Y. Jo et al., Phys. Rev Lett. 107, 055501 (2011)

3 J.Y. Jo et al., Nano Lett. 11, 3080 (2011)


Invited

I- 15

09:00 ~ 09:25, August 10

Effect of Ca-Substitution on the Ferroelectricity in CdTiO3

Hiroki Taniguchi 1* , Hiroki Moriwake 2 and Mitsuru Itoh 1

1 Materials and Structures Laboratory, Tokyo Inst. of Technology, Yokohama 226-8503,

Japan

2 Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan

* E-mail address of the corresponding author: taniguchi.h.aa@m.titech.ac.jp

Many studies have been devoted to clarify an origin of ferroelectricity in perovskite-type

oxides to date. A series of recent studies suggested that covalency plays a crucial role in an

appearance of the ferroelectricity.[1] An octahedral rotation is also known as a key factor in

the ferroelectric phase transition in the perovskite-type oxides. It is, however, not clear how

the covalency works under the existence of octahedral rotations. In the present study, we have

investigated the role of covalency in the ferroelectricity of perovskite-type oxides with preexisting

octahedral rotations, by examining Ca-substitution effect on the ferroelectricity of

CdTiO3.

CdTiO3 has an orthorhombic Pnma structure at room temperature with (a + b - b - )-type

octahedral rotations in the Glazer's notation, undergoing the phase transition into a

ferroelectric Pna21 phase at Tc ~ 85 K.[2] The phase transition is triggered by softening of a

ferroelectric soft mode, indicating a so-called displacive-type ferroelectric phase transition.[3]

In contrast, CaTiO3 that is an isomorph of CdTiO3 is paraelectric down to 0 K, in spite of its

similar crystal structure with CdTiO3. The marked difference between their phase transition

properties is expected to stem from different covalency of A-site ions, where

electronegativities of Cd and Ca are 1.7 and 1.0, respectively, whereas that of O is 3.5.

Raman scattering experiments are performed in the present study on (Cd1-xCax)TiO3 (x =

0 - 0.05) as functions of Ca-concentration and temperature. The softening of the soft mode is

found to be suppressed by the Ca-substitution to decrease Tc. First-principles calculations

clarify the soft mode in CdTiO3 is dominated by O-Cd-O asymmetric stretching, which is

closely related to the Cd-O covalent bond along the direction of spontaneous polarization in

the ferroelectric phase. It is finally suggested that weakening of the A-site covalency due to

the Ca-substitution causes the suppression of soft-mode-softening, leading to the lowering of

Tc. The present result indicates the A-site covalency also plays an important role in the

ferroelectricity in perovskite-type oxides with the pre-existing octahedral rotations.[4]

References:

[1] R. E. Cohen, NATURE 358, 136 (1992), Y. Kuroiwa et al., Phys. Rev. Lett. 87, 217601

(2001). [2] Y. J. Shan et al., Ferroelectrics 270, 381 (2002), H. Moriwake et al., Phys. Rev. B

84, 104114 (2011). [3] H. Taniguchi et al., Phys. Rev. B 76, 212103 (2007). [4] H. Taniguchi

et al., Phys. Rev. B 84, 174106 (2011)


Invited

I- 16

09:25 ~ 09:50, August 10

Phase transition behaviors of PbZr1-xTixO3 single crystals as revealed

by elastic anomalies and central peaks

Jae-Hyeon Ko 1* , Tae Hyun Kim 1,2 , Seiji Kojima 2 , Alexei A. Bokov 3 , Xifa Long 3

and Zuo-Guang Ye 3

1 Department of Physics, Hallym University, Gangwondo 200-702, Korea

2 Graduate School of Pure and Applied Sciences, Univ. of Tsukuba, Ibaraki 305-8573, Japan

3 Department of Chemistry and 4D LABS, Simon Fraser Univ., BC V5A 1S6, Canada

* E-mail address of the corresponding author : hwangko@hallym.ac.kr

Two PbZr1-xTixO3 (PZT) single crystals with x ≈ 0.45

(PZT-45) and 0.42 (PZT-42) near the morphotropic phase

boundary (MPB) were studied by Brillouin light

scattering, giving rise to the first single-crystal elastic data

which were discussed in terms of the correlation between

the acoustic anomalies and the phase transition sequence.

It is found that successive phase transitions of PZT single

crystals accompanied significant elastic anomalies and

were sensitive to the Ti concentration, which reveals new

insights into the nature of phase transitions and phase

diagram of PZT. The intense excitation of the central peak

(CP) in the paraelectric phase suggested the formation and

growth of polarization fluctuations. The relaxation time

estimated from the CP width increased upon cooling

toward TC, indicating a slowing-down of precursor dynamics. The thermal hysteresis in the

ferroelectric phase transition indicated a first-order character of the ferroelectric phase

transition for PZT-42 and an almost second-order character for PZT-45, suggesting that there

might be a tricritical point between these two compositions. A diffuse elastic softening and a

hypersonic damping were observed in both PZT single crystals below room temperature, from

which the phase boundary of the antiphase tilting transition of oxygen octahedra was

determined accurately.

* This research was supported by Basic Science Research Program through the National

Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and

Technology (2010-0010497), by the U.S. Office of Naval Research (N00014-06-10166;

N00014-11-1-0552), and by the Natural Science and Engineering Research Council of

Canada (NSERC).


Invited

I- 17

09:50 ~ 10:15, August 10

Study of local structural fluctuations in ferroelectric BaTiO3

using convergent-beam electron diffraction

Kenji Tsuda 1* , Rikiya Sano 1 and Michiyoshi Tanaka 1

1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University,

Sendai 980-8577, Japan

* E-mail address of the corresponding author: k_tsuda@tagen.tohoku.ac.jp

Convergent-beam electron diffraction (CBED) is established as the most powerful

technique to determine crystal point- and space-groups from nanometer-sized specimen areas.

The CBED method was extended to quantitative crystal structure analysis by Tsuda and

Tanaka [1, 2], which enables determinations of structural parameters such as atom positions,

atomic displacement parameters (ADPs), as well as electrostatic potential and electron density

distributions. Recently, the method was successfully applied to the electrostatic potential

analyses of silicon [3] and the orbital ordered phase of spinel oxide FeCr2O4 [4].

The CBED method has been applied to ferroelectric phases of perovskite-type BaTiO3 in

the present study. It is well known that BaTiO3 undergoes successive phase transformations

from the cubic paraelectric phase to three ferroelectric phases: tetragonal, orthorhombic and

rhombohedral ones. The mechanism of the phase transformations is, however, still not

sufficiently understood. It was pointed out from theoretical calculations that BaTiO3 is not

described as a simple displacive model but has some degree of order-disorder character [5].

Energy-filtered CBED patterns of the tetragonal, orthorhombic and rhombohedral phases

were obtained from nanometer-sized specimen areas using a JEM-2010FEF energy-filter

transmission electron microscope operated at an accelerating voltage of 100 kV with a liquidnitrogen

cooling specimen holder.

In the tetragonal and orthorhombic phases, CBED patterns were found to often show

lower symmetries than those expected from their phases. In contrast, no symmetry breaking

of CBED patterns was observed in the rhombohedral phase. These indicate that the tetragonal

and orthorhombic phases essentially have characteristic local structural disorders related to

their phase transformations, but the rhombohedral phase has no such disorder. From the

patterns of the rhombohedral phase, atom positions, anisotropic ADPs and some low-order

structure factors were successfully refined and the electrostatic potential and electron

distribution were reconstructed.

References: [1] K. Tsuda and M. Tanaka, Acta Cryst. A55, 939 (1999). [2] K. Tsuda, et al., Acta

Cryst. A58, 514 (2002). [3] Y. Ogata, K. Tsuda and M. Tanaka, Acta. Cryst. A64, 587 (2008). [4] K.

Tsuda, et al., Phys. Rev. B81, 180102 (2010). [5] W. Zhong, D. Vanderbilt and K. M. Rabe, Phys. Rev.

Lett. 73, 1861 (1994).


Invited

I- 18

10:15 ~ 10:40, August 10

Domain response by electric fields in PMN-PT: An In-situ transmission

electron microscopy study

Yukio Sato 1,2* , Tsukasa Hirayama 2 and Yuichi Ikuhara 1,2

1 Institute of Engineering Innovation, University of Tokyo, Tokyo 113-8656, Japan

2 Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan

* E-mail address of the corresponding author : y_sato@sigma.t.u-tokyo.ac.jp

Single crystal of PMN-PT (Pb(Mg1/3Nb2/3)O3-PbTiO3) is known to show high

piezoelectricity, when the composition is close to the morphotropic phase boundary region.

For better understanding of the high-piezoelectricity mechanism, not only the crystal structure,

which have been intensively investigated, but also the domain structure should be well

understood. Although there have been some reports on static domain structure of PMN-PT

with MPB composition, reports on domain responses to external stimuli such as electric fields

are quite limited. Here, we introduce our recent studies on real-time visualization of domain

responses with the use of in-situ transmission electron microscopy [1,2].

Domain structure of PMN-PT miniaturizes down to nano-meter scale, when the

composition is close to MPB (Fig. (a)). We find, for poled crystal, that domains quickly

respond upon electrical biasing that exceeds a certain critical value. Nanodomains and domain

walls (DWs) reorient upon the biasing without largely changing the density and, on the other

hand, number of micro-scale DWs reduces, showing the tendency to be more like singledomain

state. The response is reversible; the domain structure comes back to the original state

upon the release of the electric field. Further details will be given in our talk.

Figure. TEM images (a) before biasing and (b) under biasing the electric field of ~ 24.4 kV

along [111]. Corresponding domain structures are shown in (c) and (d).

References:

[1] Y. Sato et al., Phys. Rev. Lett., 107, 187601-1-5 (2011).

[2] Y. Sato et al., Appl. Phys. Lett., 100, 172902-1-3 (2012).


Invited

I- 19

10:55 ~ 11:20, August 10

Resistive switching characteristics of metal-oxide nanoparticle assembly

Tae-Sik Yoon 1*

1 Department of Materials Science and Engineering, Myongji University, Yongin,

Gyeonggi-do 449-728, Korea

* E-mail address of the corresponding author : tsyoon@mju.ac.kr

The resistive switching characteristics of metal-oxide nanoparticle (NP) assembly will be

discussed for various resistive switching-based devices such as nonvolatile resistive random

access memory (ReRAM), memristor, atomic switch, and so on. In particular, the NPs were

utilized as switching elements in contrast to the conventional thin films. Since the resistive

switching associates the nanoscale changes in metal-oxide layer including local phase change

between insulating and conducting phases, redistribution of vacancies or impurities, redox

reaction, etc, it is highly required to control these nanoscale phenomena to achieve the

uniform and reliable switching characteristics. Besides the application to current Si-based

electronics, it is also necessary to develop the proper methods for the flexible device

fabrication such as solution-based and low temperature processes. Considering these

requirements, the use of colloidal NPs is expected to be viable route due to following

advantages. The colloidal NPs are prepared as dispersed in solution and can be self-assembled

to be uniform layer upon drying the solvent through low-temperature solution processes. Also,

the nanoscale tuning of NPs such as doping with impurities, forming core-shell structure,

shaping NPs with various forms, and so on, is possible to control the resistive switching

characteristics. In this presentation, the synthesis, self-assembly, and resistive switching

characteristics of metal-oxide nanoparticles such as Fe2O3, NiO, BaTiO3 as well as Pt-Fe2O3

core-shell nanoparticles will be discussed.


Invited

I- 20

11:20 ~ 11:45, August 10

Enhanced ferroelectric properties of bismuth layer-structured ferroelectric

thick films obtained by aerosol deposition method

Muneyasu Suzuki* and Jun Akedo

Advanced Manufacturing Research Institute, National Institute of Advanced Industrial

Science and Technology, 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan

* E-mail address of the corresponding author : Suzuki.muneyasu@aist.go.jp

Bismuth layer-structured ferroelectrics has been regarded as a promising material for

applications involving ferroelectric memories and piezoelectric devices operating at high

temperatures due to its large spontaneous polarization (Ps) and high Curie temperature. Since

the layered structure leads to a strong anisotropy of the functional properties, it is of great

interest to control crystallographic orientation of grains in the form of polycrystalline

ceramics and films for achieving superior properties. The Aerosol Deposition (AD) method,

which is based on room temperature impact consolidation (RTIC) phenomena, is attracting

attention because it can form thick ceramic layers of simple or complex compositions at a

room temperature. In this study, SrBi2Ta2O9 (SBTa), Bi4Ti3O12 (BiT) and SrBi4Ti4O15 (SBTi)

ceramic thick films on glass and Pt/Ti/YSZ substrates were prepared by the AD method, and

their microstructure and polarization properties were investigated. Scanning electron

microscopy (SEM) observation revealed that starting powder of SBTa prepared by a solid

state reaction had spherically-shaped particles with the size of 1−3 �m, and starting powder of

BiT prepared by a fused salt synthesis had plate-like shaped particles with the size of

approximately 1 μm. Additionally, BiT starting powder prepared by a solid state reaction

represented square-like particles. XRD patterns measured on the surface of SBTa thick films

obtained by the AD method indicated random orientation. Compared with the BiT thick films

on glass substrates deposited using the starting powder (solid state reaction), the BiT thick

films prepared using BiT starting powder (fused salt synthesis) exhibited a much high

intensity ratio of 001 to 118. The BiT thick films on Pt/Ti/YSZ substrates were annealed at

700 °C for 30min. The annealed BiT thick films represented a remanent polarization (Pr) of

14 μC/cm 2 and a coercive field (Ec) of 70 kV/cm, which are larger than those of sintered bulk

(Pr = 9.3 μC/cm 2 and Ec = 33 kV/cm).


Contributed

Charge ordering phenomena in YFe2O4

C- 1

10:25 ~ 10:40, August 8

S. Mori 1.* , Y. Horibe 2 , T. Nagata 3 and N. Ikeda 3

1 Department of Materials Science, Osaka Prefecture University, Sakai, 599-8531, Japan.

2 Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA

3 Department of Physics, Okayama University, Okayama 700-8530, Japan.

* E-mail address of the corresponding author : mori@mtr.osakafu-u.ac.jp

Mixed-valence ferrites RFe2O4-δ (R=Y, Yb, and Lu) are one of the multiferroic materials

which is well-known for the presence of charge ordering (CO) of Fe 2+ and Fe 3+ ions on

geometrically frustrated triangular lattices[1]. RFe2O4-δ has the rhombohedral crystal structure

(space group: R 3 m) characterized by the alternative stacking of triangular-lattice Fe-O

bilayers and R-O layers along the [001] direction, and exhibits strong two-dimensionality.

Charge imbalance within bilayers in the CO state of LuFe2O4 is suggested to be responsible

for ferroelectricity below the two dimensional (2D) three-fold CO transition temperature at

about 350 K. This CO-driven ferroelectricity can be a new mechanism for ferroelectricity

from the degree of freedom of spin and charge. The evolution of three-fold CO from 2D to

three dimensional (3D) in the geometrically frustrated lattice leads to a structural phase

transition with a development of double periodicity along the [001]* direction in LuFe2O4-δ

and YFe2O4-δ. In this work, the low-temperature superstructure of YFe2O4-δ was carefully

investigated by transmission electron microscopy (TEM). We found that the unique

superstructure at about 100 K is characterized by 1/14 2 / 7 1/14 -type superlattice reflection

spots, suggesting the presence of charge reordering process [2]. The low-temperature highresolution

images clearly show superlattice modulations in Y-O layers as well as Fe-O layers.

The modification of intra-bilayer charge interactions due to lattice distortions in Y-O layers is

discussed to play a crucial role in the stabilization of long-periodic superstructures at low

temperatures. We will also report our experimental results on charge ordering phenomena in

single crystals of RFe2O4-δ (R=Y, Yb, Lu) [3].

References

[1] Y. Yamada et al., J. Phys. Soc. Jpn. 66, 3733 (1997). Phys. Rev. B 62, 12167 (2000).

N. Ikeda et al., Nature (London) 436, 1136 (2005).

[2] Y.Horibe, N. Ikeda, K. Yoshii, and S. Mori, Phys. Rev. B82, 184119 (2010).

[3].K. Matsumoto, et al., J. Phys. Conference Series, 320, 012085 (2011).

Y. Matsuo, et al., J. Phys. Conference Series, 200, 012128 1-4 (2010).

Y. Horibe, et al., Phys. Rev. B80, 092104 (2009).


Contributed

C- 2

10:40 ~ 10:55, August 8

Ferroelectric polarization driven by divalent ion-substitution into epitaxial

gallium iron oxide thin films

R. H. Shin 1,2 , S. H. Oh 1 , W. Jo 1* , C. Lefevre 3 , C. Meny 3 and N. Viart 3

1 Department of Physics, Ewha Womans University, Seoul, Korea

2 CNRS-EWHA International Research Center, Ewha Womans University, Seoul, Korea

3 Institute of Physics and Chemistry of Materials of Strasbourg, UMR 7504 University of

Strasbourg-CNRS, Strasbourg, 67043, France

* E-mail address of the corresponding author : wmjo@ewha.ac.kr

Recently, D. Stoeffler reported a first-principles study of the electric polarization and of

its switching in the multiferroic GaFeO3 system [1]. However, experimental evidence of

ferroelectric switching in this material has not been observed yet due to its mobile charges

vulnerable to external electrical bias. A specific composition like Ga0.6Fe1.4O3 (GFO) has

been extensively studied by our group over the last few years [2]. Epitaxial and

polycrystalline thin-films of GFO on various substrates are elaborated but macroscopic

polarization reversal in the films shows little saturation even up to 500 kV/cm. The GFO

thin films, where electrons between Fe 2+ and Fe 3+ sites are itinerant, shows large DC

conductivity. In order to reduce the current transport in the films, divalent ion-substitution

of Mg 2+ and Co 2+ is attempted. By controlling concentration of the substituted ions, the

current density of the ion-substituted GFO thin films was surprisingly reduced by 10 3 or

larger. Ferroelectric polarization of the ion-substituted GFO thin films was measured using

macroscopic switching measurement and piezoresponse force microscopy. At the

composition that exhibit lowest conductivity, we obtain a promising polarization reversal

behaviors with significant remnant polarization and domain wall switching.

[1] D. Stoeffler, J. Phys.: Condens. Matter 24, 185502 (2012).

[2] M. Trassin et al. Appl. Phys. Lett. 91, 202504 (2007); J. Mater. Chem.19, 8876 (2009).


Contributed

C- 3

12:00 ~ 12:15, August 8

Capabilities of BaTiO3 and SrTiO3 Nanocube Self-Assemblies

Kazumi Kato 1 , Ken-ichi Mimura 1 , Feng Dang 1,2 , Hiroaki Imai 2 , Satoshi Wada 3 ,

Hajime Haneda 4 and Makoto Kuwabara 5

1 National Institute of Advanced Industrial Science and Technology, 2266-98 Anagahora,

Shimoshidami, Moriyama, Nagoya, Japan

2 Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Japan

3 University of Yamanashi, 4-3-11, Takeda, Kofu, Japan

4 National Institute for Materials Science, 1-1 Namiki, Tukuba, Japan

5 Kyushu University, 6-1 Kasuga-kouen Kasuga, Fukuoka, Japan

* E-mail address of the corresponding author : kzm.kato@aist.go.jp

The BaTiO3 and SrTiO3 nanocubes were synthesized by hydrothermal method using a

water-soluble titanium complex. The microstructure of dielectric nanocubes was observed

by a high resolution transmission electron microscope (HR-TEM). The size of BaTiO3 and

SrTiO3 nanocubes was about 15 nm. The high magnification profiles indicated that each had

a cubic shape with sharp edges and clear lattice fringes without inner voids. Based on these

crystallographic appearances, the nanocubes were confirmed to be high quality single crystals.

The capillary force assisted self-assembly method was adopted to fabricate the ordered

structures on Si and Pt-coated Si substrates. The orderly region of BaTiO3 nanocubes was

over a very wide range in tens of micrometers because of the narrow size and shape

distributions of nanocubes in non-polar organic solvent. BaTiO3 nanocubes were assembled

face to face and the resultant structure of assembly was dense in order. The relative density

of the assemblies was about 98%. The piezoelectric properties of the orderly assemblies on

Pt-coated Si substrate were characterized by a piezoresponse force microscope (PFM). The

SrTiO3 nanocubes assemblies showed a linear d33-V relation because of the paraelectric

electrostriction. On the other hand, the BaTiO3 nanocubes assemblies exhibited a

ferroelectric hysteresis loop. The mixture nanocube assemblies showed a distinguished

behavior, which was a combination of non-linear in the range of low poling field and stepwise

changes in the range of high poling field. It suggested that BaTiO3/SrTiO3 hetero-interfaces

were existed in the assembly of mixture nanocubes and affected the dielectric properties.

The interface-designed structures consisted of cubic shaped dielectric building blocks have

potentials to tune the piezoresponse properties and would be expected for future dielectric

device applications. Great capabilities of the dielectric nanocubes will be addressed.

This work was supported by the Collaborative Research Consortium of Nanocrystal

Ceramics in Japan.


Contributed

C- 4

14:45 ~ 15:00, August 8

Examination on the ferroelectricity in HfxZr1-xO2 thin film

Min Hyuk Park * , Han Joon Kim, Yu Jin Kim, Hyo Kyeom Kim, Il-Hyuk Yoo

and Cheol Seong Hwang

WCU Hybrid Materials Program, Department of Material Science & Engineering and Interuniversity

Semiconductor Research Center, Seoul National University, Seoul 151-744, Korea

* E-mail address of the corresponding author : pmh1983@snu.ac.kr

Ferroelectric (FE) thin fims have been considered as the most feasible material for

universal random access memory thanks to their bistable polarization which can be fast and

reversibly switched by a small voltage pulses. However, the development of ferroelectric

memories, such as FeRAM and FeFET, has been deterred mainly due to the difficulty of

fabricating nano meter scale ferroelectric thin films which usually have complicated chemical

composition and crystal structures. Most extensively studied FE materials are PZT and SBT,

but they are still not in large scale volume production due to many issues, such as too thick

minimum thickness to be used in 20 – 30 nm scale memory devices and difficult fabrication

of them on three dimensional (3D) geometry. Recently, ferroelectricity in HfO2-based

materials with various dopants was reported, which could be a new pathway for the giga-bit

density FE memories due to the following reasons. First, HfO2 is compatible with

conventional Si technology, and it is already used in mass production. Second, relatively thin

(


Contributed

C- 5

16:30 ~ 16:45, August 8

Sintering of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead – free piezoelectric ceramics.

John G. Fisher 1* , Dae-Gi Lee 1 , Jeong-Hyeon Oh 1 , Ha-Nul Kim 1 , Dieu Nguyen 1

and Ho-Yong Lee 2

1

School of Materials Science and Engineering, Chonnam National University,

Gwangju 500-757, Republic of Korea.

2

Department of Advanced Materials Engineering, Sun Moon University, Asan,

Chungnam 336-708, Republic of Korea.

* E-mail address of the corresponding author : johnfisher@jnu.ac.kr

BaTiO3 was one of the first piezoelectric ceramics to be discovered, but was quickly

eclipsed by Pb(Zr,Ti)O3. The need for lead-free piezoceramics has caused a renewal of

interest in BaTiO3 – based systems. Recently, Liu and Wren found that ceramics in the

(Ba,Ca)(Zr,Ti)O3 system have properties comparable to those of Pb(Zr,Ti)O3.[1] However,

these ceramics require rather high sintering temperatures of 1450-1550�C.[2,3] In this

presentation, the effect of TiO2 and CuO addition on the sintering behavior, microstructure,

dielectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCTZ) ceramics will be

discussed. BCTZ ceramics were prepared by the mixed oxide route and 1 mol % of TiO2 or

CuO was added. Undoped and doped ceramics were sintered at 1350�C and 1400�C for 1-5

hours. CuO was found to be a very effective sintering aid, with samples sintered for 1 hour at

1350�C having a bulk density of 95% theoretical density; however the piezoelectric properties

were greatly reduced compared to those in the literature.

[1] Liu W, Ren X Large piezoelectric effect in Pb-free ceramics. Phys Rev Lett 103: 257602 1-4 (2009)

[2] Li W, Xu Z, Chu R, Fu P, Zang G Piezoelectric and dielectric properties of (Ba1-xCax)(Ti0.95Zr0.05)O3 leadfree

ceramics. J Am Ceram Soc 93: 2942-44 (2010)

[3] Wang P, Li Y, Lu Y Enhanced piezoelectric properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free ceramics by

optimizing calcination and sintering temperature. J Eur Ceram Soc 31: 2005-2012 (2011)


Contributed

C- 6

16:45 ~ 17:00, August 8

Interfacial Reactions for Co-fired Ni-(Na,K)NbO3 piezoceramics

Ken-ichi Kakimoto, Kensuke Kato and Isao Kagomiya

1 Department of Materials Science and Engineering, Graduate School of Engineering,

Nagoya Institute of Technology, Nagoya 466-8555, Japan

* E-mail address of the corresponding author : kakimoto.kenichi@nitech.ac.jp

(Na,K)NbO3–based ceramic system is now studied most intensively from the practical

point of view for lead-free piezoelectric transducer application. However, their piezoelectric

properties such as an electrical-field-induced displacement, which is one of the important

characters for piezoelectric actuator application, is still much lower than those of PZT system.

Under this situation, an importance of multilayer structure has been recognized more recently.

On the other hand, (Na,K)NbO3–based ceramic system shows an advantage against PZT

system in the sintering under a reduced atmosphere, which is similar to the case of BaTiO3based

multilayer ceramic capacitors (MLCCs). It is therefore expected that non-precious Ni

metals will be adopted as an inner electrode to fabricate cost-effective (Na,K)NbO3–based

multilayer piezoelectric actuators. In general, it has been known that Ni electrodes

demonstrate high electromigration resistance under large electrical fields and excellent

interfacial strengths with ceramic matrix under wide service temperatures, compared with

precious Ag-Pd electrodes used in current PZT actuators. However, there is still in a lack of

knowledge on the interfacial stability and reaction between Ni and (Na,K)NbO3 during their

co-fired process.

In this work, we studied the chemical stabilities of Ni-(Na,K)NbO3 interfaces during heat

treatments processed in reducing atmospheres with various oxygen partial pressures from 10 -

10 -20

atm down to around 10 atm as minimum. The oxidation of Ni, a new phase formation,

solid-solution reactions will be reported from the systematic investigations based on various

model experiments. The motivation of the present study is to provide a new insight into

possible interfacial reaction pathways based on thermodynamics and defect chemistry.


Contributed

C- 7

11:45 ~ 12:00, August 10

Fabrication of lead-free textured (Na0.53K0.47)(Nb0.55Ta0.45)O3 ceramics by

reactive templated grain growth using NaNbO3 templates

A. Hussain 1 , J. S. Kim 1 , G. H. Ryu 1 , T. K. Song 1 , M. H Kim 1* and W. J. Kim 2

1 School of Nano & Advanced Materials Engineering, Chanwon National University,

Gyeongnam 641-773, Republic of Korea

2 Department of Physics, Changwon National University, Gyeongnam 641-773, Republic of

Korea

* E-mail address of the corresponding author : mhkim@changwon.ac.kr

High performance, lead-free piezoelectric ceramics have received considerable research

attention as potential candidate materials for replacements of lead-based perovskite, such as

Pb(Zr, Ti)O3 (PZT). In particular, much recent work has focused on (Na, K)NbO3 (NKN)

perovskite system. However, Pure NKN ceramics are difficult to sinter by conventional

methods, and show inferior properties in comparison with PZT. To improve the performance

of NKN ceramic system, different techniques for their fabrication such as spark plasma

sintering, screen printing, templated grain growth, and reactive templated growth have been

employed. Among these techniques, the reactive templated grain growth (RTGG) has proved

to be more effective in improving the piezoelectric performance. In this work, we have

synthesized (Na0.53K0.47)(Nb0.55Ta0.45)O3 (NKNT) ceramics by reactive templated grain

growth using plate like NaNbO3 (NN) templates. The NN templates were synthesized from

bismuth layered-structure ferroelectric Bi2.5Na3.5Nb5O18 (BNN) particle by topochemical

microcrystal (TMC) conversion method. The degree of grain orientation and the grain

morphologies were examined by XRD and SEM analysis, respectively. We have found that

NKNT grain oriented ceramics prepared by RTGG technique exhibited superior dielectric and

piezoelectric properties than those of randomly oriented ceramics.


Poster Session I

17:00 ~ 18:30, August 8

Gallery, 2F, International Building


Poster session I

Increasing Torque of One Touch Point Ultrasonic Linear Motor by using

Multilayer Ceramics

Seong Su Jeong 1 , Jung Hoon Lim 1 , Seong Kyu Cheon 1 , Na Lee Kim 1 , Jong Kyu Park 2 ,

Myong Ho Kim 3 and Tae Gone Park 1*

1 Department of Electrical Engineering, Changwon University, Changwon 641-773, Korea

2 Department of Mechanical Engineering, Changwon University, Changwon 641-773, Korea

3 School of Nano and Advanced Materials Engineering, Changwon University, Changwon

641-773, Korea

* E-mail address of the corresponding author : tgpark@changwon.ac.kr

In this paper, one touch point ultrasonic linear motor was proposed. The stator of the

motor is easy to fabricate because of the simple structure and the punching technique. Also,

the thin stator is advantageous to use in tight thin spaces. Metal plate was used as a vibrating

plate of the V-shaped stator and four ceramic plates were attached to the upper and lower

surfaces of the plate. When two sinusoidal sources with phase difference of 90 degrees are

applied to the stator, elliptical displacement is generated at contact tip of the stator. Modeling

of the ultrasonic motor was done and the displacement characteristics were defined by using

finite element analysis (ATILA). To improve the speed and torque, the ultrasonic motor was

analyzed by changing the angle of the legs and using multilayer ceramics. Also, a selected

motor which has large X-axis and Y-axis displacements was fabricated and the speed and

torque of the motor were measured.

P- 1


Poster session I

Photocurrent behaviours of Pt/BNT/Pt and Pt/NKBiT/Pt capacitors

Sung Sik Won, Chang Won Ahn, Won Seok Woo, Song A Chae,

Hae Jin Seog and Ill Won Kim *

Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan,

Ulsan 680-749, South Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

When ferroelectric materials are illuminated by light beam, voltage and current can be

generated due to separation of photoinduced electrons and holes by its internal electric field.

Such photovoltaic phenomena in the ferroelectric thin films exhibit potential applications for

realizing remote control and wireless energy transfer in microelectromechanical system

(MEMS) device. Recently, lead-free ferroelectric materials have been a matter of great

interest because of the environmental pollution coming from toxic lead based materials. The

Bi0.5Na0.5TiO3 (BNT) and (Na0.82K0.18)0.5Bi4.5Ti4O15 (NKBiT) ferroelectric thin films exhibit

good ferroelectric properties. So, we have investigated the photocurrent behaviours of the Pt

sandwiched BNT and NKBiT thin films deposited by chemical solution deposition method.

Ferroelectric P-E hysteresis loops, current-voltage and photocurrent behaviours are discussed.

The mechanism behind the origin of the different photocurrent behaviours between Pt/BNT/Pt

and Pt/NKBiT/Pt capacitors was discussed.

P- 2


Poster session I

Photovoltaic effect of (Na0.82K0.18)0.5Bi4.5Ti4O15 thin film with Pt and

ITO top electrodes

Won Seok Woo, Sung Sik Won, Chang Won Ahn,

Song A Chae and Ill Won Kim *

Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan,

680-749, Ulsan, South Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

Recent studies revealed that the ferroelectric films exhibited interesting photoelectric

properties in the ultraviolet (UV) regions with the potential applications for energyindependent

memories based on nondestructive optical reading, UV detection and

photovoltaic devices. The layered bismuth structure has a four-layered perovskite unit of

((Na0.82K0.18)0.5Bi4.5Ti4O13) 2- sandwiched by two (Bi2O2) 2+ layers along the c axis. We have

investigated photoelectric behavior of the Pt and ITO top electrodes sandwiched Bi layered

structure (Na0.82K0.18)0.5Bi4.5Ti4O15 (NKBiT15) film deposited by chemical solution

deposition. Based on the analysis of the photocurrent and I-V characteristics the Schottky

barrier of Pt/film/Pt capacitor displayed symmetric behavior, but that of ITO/film/Pt capacitor

exhibited asymmetric behavior. Photovoltaic power conversion efficiency of NKBiT15 thin

films with Pt and ITO top electrodes were investigated. The mechanism behind the origin of

the different photocurrent behaviors between Pt/film/Pt and ITO/film/Pt capacitors was

discussed. The observed photocurrent of NKBiT15 films strongly depends on the wavelength

of incident light beam. Maximum photocurrent of NKBiT15 thin films was obtained at -30.2

nA/cm 2 around 356 nm. The band gap energy of the NKBiT15 thin films was 3.4 eV.

P- 3


Poster session I

Control of Oxygen Vacancies by Plasma Enhanced Atomic Layer

Deposition (PEALD) of TiO2 for Memristors

Sang-Joon Park 1,2 , Jeong-Pyo Lee 1 , Jong Shik Jang 1 , Hyun Rhu 1 , Hyunung Yu 1 ,

Byung Youn You 1 , Chang Soo Kim 1 , Kyung Joong Kim 1 , Yong-Jai Cho 1 ,

Sunggi Baik 2 and Woo Lee 1,3*

1 Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340, Korea

2 Department of Materials Science & Engineering, Pohang University of Science and

Technology (POSTECH), Pohang 790-784, Korea

3 Department of Nano Science, University of Science and Technology (UST), Yuseong,

Daejeon 305-333, Korea

* E-mail address of the corresponding author : woolee@kriss.re.kr

TiOx is one of the most extensively studied materials for resistive switching (RS)

applications. It has been generally accepted that the formation and rupture of conducting

path(s) of oxygen deficient Magnéli phase resulting from field-induced migration and

ordering of oxygen vacancies (VO) is mainly responsible for the resistive switching (RS) in

TiOx-based RS devices. In this regard, it is important to investigate the effect of oxygen

vacancy concentration on the RS behaviors of the TiOx-based memristors. To this end,

Pt/TiOx/Pt capacitors with different values of x were prepared. It has been well established

that stoichiometry of TiOx was closely related to the oxygen vacancy concentration. TiOx

films were grown by plasma enhanced atomic layer deposition (PEALD) at the substrate

temperature of 150 °C. Titanium (IV) tetraisopropoxide (TTIP; Ti[OCH(CH3)2]4) was used as

a Ti precursor. High purity oxygen or mixture gas of pure oxygen and nitrogen was adopted

as a reactant during the plasma exposure step. It is noted that the stoichiometry of TiOx films

were deliberately controlled from x = 1.62 to 1.70 by adjusting the flow rate ratio (RF) of O2

gas to N2 + O2 mixture gas from 0.25 to 1.00. Phases of PEALD TiOx films were found to be

amorphous at RF = 0.25, whereas nanocrystalline anatase at RF = 1.00. Confocal Raman

spectroscopic analysis provided an additional evidence for evolution of the film crystallinity

with RF,viz., x in TiOx. It was found from the deconvolution of the O1s XPS peaks that nonlattice

oxygen content increase from 15.3 to 20.7 % with decreasing the RF from 1.00 to 0.25,

indicating the increases of oxygen vacancies in PEALD TiOx film with RF. From

spectroscopic ellipsometry analyses, absorption by the defect states below bandgap increases

with decrease of x, i.e., increase of oxygen vacancy. The effect of oxygen vacancy

concentration on RS behaviors of TiOx-based memristors will be discussed in detail in this

presentation.

P- 4


Poster session I

Piezoelectric Energy Scavenger based on PZT LTCC Cantilever

Seung Eon Moon 1* , Woo Seok Yang 1 , Jongdae Kim 1 and Yeong Sung Wang 2

1 Nano Convergence Sensor Research Team, Electronics and Telecommunications Research

Institutue, Daejeon 305-700, Korea

2 Lattron, Daejeon 306-230, Korea

* E- mail address of the corresponding author : semoon@etri.re.kr

In this paper, we present the results of a preliminary study on the piezoelectric energy

scavenging performance of a PZT low temperature co-firing ceramic (LTCC) beam. A novel

piezoelectric beam cantilever structure is used to demonstrate the feasibility of generating AC

voltage during a state of vibration. The energy-scavening capability of a PZT LTCC beam is

tested. The frequency response of the cantilever device shows that the first mode resonance

frequency of the excitation model exists in the neighborhood of several hundreds of hertz.

These tests show that a few open AC voltages and sub-mW power are achieved. To test the

possibility of a small scale power source for a ubiquitous sensor network service, energy

conversion and the testing of storage experiment are also carried out.

P- 5


Poster session I

Lead-free alkaline niobates nanostructures for piezoelectric nanogenerators

Byung Kil Yun 1 , Jong Hoon Jung 1* and Zhong Lin Wang 2

1 Department of Physics, Inha University, Incheon 402-751, Korea

2 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA

30332, USA

* E-mail address of the corresponding author : jhjung@inha.ac.kr

Perovskite ferroelectric nanowires have rarely been used for the conversion of tiny

mechanical vibrations into electricity, in spite of their large piezoelectricity. Here we present

the lead-free alkaline ferroelectric nanowires based piezoelectric device for the high output

and cost-effective flexible nanogenerator. The device consists of a alkaline niobates

nanostructures-poly(dimethylsiloxane) polymer composite and Au/Cr coated polymer films.

High quality alkaline niobates nanowires/nanorods can be grown by hydrothermal method at

low temperature and can be poled by an electric field at room temperature. The composite

device shows an output voltage of ~3.0 V and output current of ~70 nA under a small

compressive strain. These results imply that alkaline niobates ferroelectric nanostructures

should be quite useful for the lead-free piezoelectric nanogenerator applications.

P- 6


Poster session I

Transient Negative Capacitance in Domain Wall of Ferroelectric Thin

Films

Yu Jin Kim 1* , Min Hyuk Park 1 , Han Joon Kim 1 , Doo Seok Jeong 2 , Anquan Jiang 3

and Cheol Seong Hwang 1

1 WCU Hybrid Materials Program, Department of Material Science & Engineering and Interuniversity

Semiconductor Research Center, Seoul National University, Republic of Korea

2 Electronic Materials Center, Korea Institute of Science and Technology, Republic of Korea

3 State Key Laboratory of ASIC & System, Department of Microelectronics, Fudan

University, Shanghai, 200433, China

* E-mail address of the corresponding author : uzinknig@snu.ac.kr

The bi-stable polarization states of ferroelectric (FE) materials received a great deal of

attention for its application to electronic devices. Especially, one of the most intriguing topics

of ferroelectric application in recent years is the involvement of the negative capacitance

(NC) effect in the ferroelectrics in FE – dielectrics (DE) stacked system. [1] If NC effect is

stably obtained, it may revolutionize the electronic devices because capacitance is not a

simple linear function of area anymore. Furthermore, voltage can be amplified without using

external circuit. This means that the conventional scaling rule for semiconductor devices must

be changed. However, this can be fundamentally difficult because of the very high tendency

of domain formation in ferroelectric thin film system; especially the FE-DE system could

involve a serious depolarization effect which profoundly favors the poly-domain structure.

In this work, the authors observed NC effect from the domain wall of ferroelectric thin

film in a FE-DE stacked system. It is considered that the physical state of domain wall region

is prone to show NC because P ~ 0 there but still the crystal structure is the same as FE bulk.

In normal FE switching, the domain propagation is generally quite fast, so observing the

electric response of the domain wall regions is rather difficult. Therefore, the authors

designed several FE-DE systems where the DE controls the compensating charge injection to

an appropriate level and enhance the chance to see the responses of domain boundaries to the

electric pulses. This must be a thermodynamically reasonable result considering polarization

compensated charge contribution to the Landau’s phenomenological model. Detailed

experimental and model study results will be presented.

[1] S. Salahuddin and S. Datta, Nano Lett. 8, 405 (2008)

P- 7


Poster session I

Enhanced Dielectric and Piezoelectric Properties of BaTiO3-Based Single

Crystals by Defect-Polarization Control

Shotaro Ishikawa 1* , Yuuki Kitanaka 1 , Takeshi Oguchi 1 , Yuji Noguchi 1 ,

Masaru Miyayama 1 , Chikako Moriyoshi 2 and Yoshihiro Kuroiwa 2

1 Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1

Komaba, Meguro-ku, Tokyo 153-8904, Japan

2 Department of Physical Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima,

Hiroshima 739-8526, Japan

* E-mail address of the corresponding author : s-ishikawa@crm.rcast.u-tokyo.ac.jp

Ferroelectric-related properties are governed by domain structures and their dynamics

with respect to electric field, [1] which is greatly influenced by lattice defects. [2] Defect

chemistry of barium titanate (BaTiO3: BT) is dominated by acceptor impurities that are

inevitably present in raw materials. [2] It has been reported that dielectric and piezoelectric

properties for thin films or ceramics of BT and Pb-based ferroelectrics are improved by the

doping of acceptors such as Mn, [3] but the details of the defect structure are not clear. To

develop materials design of ferroelectrics, it is considered essential to control the domain

dynamics based on the defect chemistry. The aim of this study is to establish materials design

for enhancing dielectric and piezoelectric properties based on “defect-polarization control”.

The defect-polarization control is defined as the domain engineering based on defect

chemistry, in which the strong attractive interaction between domain walls and oxygen

vacancies [4] are utilized to stabilize nanometer sized domains. Here, BT is chosen as a model

material and the single crystals of BT-based materials were used for evaluations.

Mn-doped BT single crystals were grown by a top-seeded solution growth (TSSG)

method in air. Crystals with 14×14×11 mm 3 size were obtained (Fig. 1). Mn (0.1 %)-doped

BT crystals (Mn-BT) showed a piezoelectric strain constant d33 along cubic of 630 pm/V

(Fig. 2.), which was much larger than those of undoped BT crystals and single-domain BT

crystals (86 pm/V [5] ). Piezoresponse-force microscope observations showed that Mn-BT

poled along cubic had a peculiar domain structure with a size of 20-40 nm. In-situ

synchrotron X-ray diffraction analysis indicated that Mn-BT has the tetragonal P4mm

structure regardless of electric filed whereas undoped BT crystals undergo an electric-field-

induced phase transition from the tetragonal P4mm to orthorhombic or monoclinic structures.

[1] S. Wada. et al.,

Ferroelectrics, 334, 17

(2006).[2] D. M. Smith.

et al., J. Am. Ceram. Sci.,

0.06

0.04

64, 9 (1981).[3] H. Kishi.

et al., Jpn. J. Appl. Phys.,

39, 5533 (2000).[4] Y.

Kitanaka. et al., Phys.

Rev. B 81, 094114 (2010).

[5] D. Berlincourt et al.,

Phys. Rev., 111, 143

(1958).

0.02

0.00

0 2 4 6 8 10

Electric Field /kVcm �1

c

25 ℃ 1 Hz

E // c

x = 0.1 %

14 mm

Fig.1 The photo of 0.5 % Mndoped

BT crystals obtained by

a TSSG method.

x = 0 % (BT)

Fig.2 Piezoelectric strain of

0.1 % Mn-doped BT crystals

and BT crystals.

P- 8

Strain / %


Poster session I

Influence of 60 o domain structure on orthorhombic niobate-based

piezoelectric property

Kohei Tsuchida * , Ken-ichi Kakimoto and Isao Kagomiya

Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya

Institute of Technology, Nagoya 466-8555, Japan

* E-mail address of the corresponding author : cjk15059@stn.nitech.ac.jp

Lead-free (Na,K)NbO3 (NKN)-based ceramics have been expected to be applied to

sensors and actuators at high temperature because of their relatively good piezoelectric

property and high Curie temperature. However, their piezoelectric properties are not well over

Pb(Zr,Ti)O3(PZT)-based ceramics. In addition, NKN ceramics show difficulty and less

reproducibility to prepare high density samples by a conventional solid-state reaction under

atmospheric pressure. Therefore, the advancement of the sinterability and electric properties

by the improvement of sintering and synthesis process has been investigated. In contrast, the

study of ferroelectric domains of NKN ceramics is not enough to be investigated, and this is

necessary for better understanding and improvement of their inherent properties.

In the case of PZT ceramics, the change of domain structure during poling process was

clearly discussed and the influence of 90 o domain structure on the strain was well known.

NKN ceramics belong to the space group of orthorhombic Bmm2 which show a lower

symmetric structure than tetragonal P4mm PZT ceramics at room temperature. Therefore,

NKN ceramics show a complex domain structure including 60 o domains besides 90 o domains.

However, there have been only a few detailed reports on the change of domain structure under

applied electrical field on NKN ceramics.

In this study, we evaluated the response of 90 o and 60 o domain structures under applied

electrical fields on NKN ceramics. For NKN crystal, the amount of strain that is induced by

domain switching was attributed to their direction of spontaneous polarization of 90 o and 60 o

domain structures. Therefore, we now advance in the study of the domain dynamics based on

changes of crystallite orientation under various poling fields by using an X-ray diffraction

method and electrical-field induced strain of NKN ceramics. As a result, we firstly found an

advantage of orthorhombic NKN ceramics on thermal dependence of their piezoelectric

property.

P- 9


Poster session I

Nanoscale visualization of domain wall pinning process as the origin of

polarization fatigue

Yeong Jae Shin 1* , Sang Mo Yang 1 , Tae Heon Kim 1 , Jong-Gul Yoon 2

and Tea Won Noh 1

1 ReCFI, Department of Physics and Astronomy, Seoul National University, Seoul 151-747,

Korea

2 Department of Physics, University of Suwon, Hwaseong, Gyunggi-do 445-743, Korea

* E-mail address of the corresponding author : yjshin@phya.snu.ac.kr

The microscopic mechanism of polarization fatigue (i.e., a loss of switchable

polarization under electrical cycling) remains one of the most important long-standing

problems in ferroelectric communities. Although there are numerous proposed fatigue models,

a consensus between the models and experimental results is not reached yet.

Here, we present the visualization of nanoscale domain switching dynamics for different

fatigue stages in epitaxial PbZr0.4Ti0.6O3 capacitors by using modified-piezoresponse force

microscopy [1]. Systematic time-dependent studies of the domain nucleation and evolution

allow us to find that domain wall pinning, rather than nucleation inhibition, is the primary

origin of fatigue. Especially, we can directly observe the evolution of domain wall pinning

process during electrical cycling, from the suppression of sideways domain growth in early

fatigued stages to the blockage of forward domain growth in later stages.

Reference: [1] S. M. Yang et al., Adv. Funct. Mater. (2012), published online.

P- 10


Poster session I

Preparation of Epitaxial BiFeO3 Thin Films on La-SrTiO3 Substrate by

Magnetic-Field-Assisted Pulsed Laser Deposition

Jung Min Park 1 *, S. Nakashima 2 , M. Sohgawa 1 , T. Kanashima 1 and M. Okuyama 3

1 Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan

2 Graduate School of Engineering, University of Hyogo, Hyogo 671-2201, Japan

3 Institute for NanoScience Design, Osaka University, Osaka 560-8531, Japan

* E-mail address of the corresponding author: jmpark@semi.ee.es.osaka-u.ac.jp

Bismuth ferrite (BiFeO3, BFO) is well known as a multiferroic material, exhibiting

ferroelectric and anti-ferromagnetic properties. In particular, epitaxial BFO thin film on

SrTiO3 (STO) substrate prepared by a pulsed laser deposition (PLD) has large polarization

value (55 µC/cm 2 ) at RT. 1) Recently, good epitaxial BFO thin films have been prepared on

vicinal STO substrate with various deposition methods such as MOCVD and off-axis

sputtering. 2) In this study, we have prepared epitaxial BFO thin film by using magnetic field

assisted PLD method as a new deposition method, having a high deposition rate due to

modification of ion trajectory under magnetic field. 3)

Magnet was set between the target and the substrate in the vacuum chamber, and

magnetic field was applied perpendicularly to the substrate during film deposition. Epitaxial

BFO thin films were prepared on La (3.75 wt%)-doped STO single crystal substrate of

conductive electrode at a substrate temperature of 700 o C and O2 pressure of 0.02 ~ 0.1 Torr

under magnetic field of 0, 0.1, and 0.4 T.

XRD patterns of epitaxial BFO thin films prepared under 0, 0.1, and 0.4 T show only the

(001) diffraction peaks without secondary phases. From result of reciprocal space mapping

(RSM), (003) planes for epitaxial BFO thin films prepared under 0, 0.1 and 0.4 T show peak

splitting and lattice parameters of out of plane were 0.397, 0.397 and 0.396 nm, respectively.

Moreover, peak splitting of (103) and (-103) reflection is observed and lattice parameters of

in-plane in rhombohedral structure were 0.397, 0.397, and 0.396 nm for the films prepared

under 0, 0.1, and 0.4 T, respectively. P-E hysteresis loop in all the epitaxial films was

obtained at RT and remanent polarization (Pr) of the film prepared under 0.1 T was 46

µC/cm 2 , while current density was reduced in an epitaxial BFO thin film prepared under 0.1 T.

1) J. Wang et al., Science 299 1719 (2003)

2) R. Ramesh, and C. B. Eom et al., Phase transitions 79 991 (2006)

3) J. M. Park et al., Jpn. J. Appl. Phys. 50 09NB03 (2011)

P- 11


Poster session I

Equilateral triangle closure domains in (111)-oriented epitaxial

PbZr0.35Ti0.65O3 thin films

Sang Mo Yang 1* , Young Jae Shin 1 , Hiroshi Funakubo 2 , Jong-Gul Yoon 3 ,

James F. Scott 4 , and Tae Won Noh 1

1 ReCFI, Department of Physics and Astronomy, Seoul Nat’l Univ., Seoul 151-747, Korea

2 Dept. of Innovative and Engineered Material, Tokyo Institute of Technology,

Yokohama 226-8503, Japan

3 Dept. of Physics, Univ. of Suwon, Hwaseong, Gyunggi-do 445-743, Korea

4 Dept. of Physics, Cavendish Laboratory, Univ. of Cambridge, Cambridge CB3 0HE, UK

* E-mail address of the corresponding author : smyang@phya.snu.ac.kr

Topological defects in ferroelectrics and multiferroics have attracted significant attention

both as a playground of exotic physical phenomena and for potential applications in

reconfigurable electronic devices [1]. One example of such topological defects is a flux-closure

domain. The flux-closure domain in ferroics indicates the arrangements of local order parameters,

which are rotated continuously with satisfying the head-to-tail alignment. The driving force

behind the formation of flux-closure domain states is the minimization of depolarizing or

demagnetizing fields, achieved through the creation of head-to-tail dipolar or magnetic loops.

While these intriguing domain patterns are commonly observed in ferromagnetics, its existence in

ferroelectrics is not yet well established and understood. Quite recently, a burgeoning interest in

ferroelectric as well as multiferroic closure domain states has developed, leading to a profusion of

both theoretical and experimental studies [2].

Here, we report on the observation of novel topological defect structure and investigation of

its electrical properties in the 3-fold rotational symmetry ferroelectric system. We explored

nanoscale ferroelectric domain configurations in 160 nm (111)-oriented epitaxial PbZr0.35Ti0.65O3

films by using piezoresponse force microscopy. After out-of-plane polarization switching by a

poling process, we observed a very intriguing change of ferroelectric in-plane domains, i.e., the

formation of equilateral triangle closure domains. Using conductive-atomic force microscopy, we

investigated the local electric conductivities of this exotic topological defect structure, and found

that the intersection point of domain walls (called vertex) exhibits significant electric

conductivities compared with the surrounding regions.

[1] N. Balke et al., Nature Physics 8, 81 (2012).

[2] G. Catalan et al., Review of Modern Physics 84, 119 (2012).

P- 12


Poster session I

Effect of Composition on the ferroelectric properties of HfxZr1-xO2 thin film

Han Joon Kim 1* , Min Hyuk Park 1 , Yu Jin Kim 1 , Hyo Kyeom Kim 1 , Il-Hyuk Yu 1

and Cheol Seong Hwang 1

1 WCU Hybrid Materials Program, Department of Material Science & Engineering and Interuniversity

Semiconductor Research Center, Seoul National University, Seoul 151-744, Korea

* E-mail address of the corresponding author : june110@snu.ac.kr

Ferroelectric random access memory (FeRAM), and Ferroelectric Field-Effect-

Transistor (FeFET) have been regarded as the most promising universal non-volatile

memories due to its reversibly bi-stable polarization states. Most of the former researches

have focused on the material system based on the perovskite structure. However, such system

suffers from several problems; the size effect, difficult fabrication process, relatively small

bandgap, and very high dielectric constant. As a result, the development of very high density

FeRAM has been deterred and other emerging memories, such as PcRAM, ReRAM, and

MRAM, attracts a greater deal of attention at the moment. However, it was recently reported

that HfO2 can show ferroelectric properties when doped with various dopants such as Si, Y,

Al, and Zr. [1-2] This could revolutionize the field of ferroelectrics. Due to its small thickness

and matured atomic layer deposition technique, Hf based ferroelectrics can be compatible

with conventional Si technology and appropriate for 3-D capacitor. Among various dopants,

Zr seems to be the most promising which has almost identical chemical property as that of Hf.

However, there has not been a systematic report on the effect of composition on the

ferroelectric properties of HfxZr1-xO2 (HZO) films. In this presentation, HZO capacitors with

various compositions were fabricated and its electrical characteristics will be reported. It was

confirmed that HZO system show ferroelectric property in a wide range of compositions, and

samples with stoichiometric Hf0.5Zr0.5O2 showed the largest Pr values and most square-shaped

P-V curves. With increasing the Zr composition, Pr and dielectric constant decreased and antiferroelectric

appears. In Hf-rich condition, on the other hand, the same result was obtained,

but with no anti-ferroelectric behaviour. The structure of HfxZr1-xO2 film changes from

orthorhombic to tetragonal (monoclinic) when x decreases (increases) below 0.5. Other

ferroelectric parameters depending on the various compositions will also be reported.

[1] T. S. Böscke, J. Müller, D. Bräuhaus, U. Schröder, and U. Böttger, Appl. Phys. Lett. 2011 ,

99 , 102903.

[2] J. Müller , T. S. Böscke , D. Bräuhaus , U. Schröder , U. Böttger , J. Sundqvist , P.

Kücher , T. Mikolajick , and L. Frey , Appl. Phys. Lett. 2011 , 99 , 112901.

P- 13


Poster session I

Phase effect of the polycrystalline BiFeO3 thin film by puled laser

deposition

H. I. Choi 1 , M. H. Lee 2 , S. W. Kim 1 , W. J. Kim 1* , J. S. Park 2 , D. J. Kim 2 , D. Do 2 ,

T. K. Song 2 and M. H. Kim 2

1 Department of Physics, Changwon National University, Changwon 641-773, Korea

2 School of Nano & Advenced Material Engneering, Changwon National Univerisity,

Changwon 641-773, Korea

* E-mail address of the corresponding author : kwj@changwon.ac.kr

The bismuth ferrite, BiFeO3 (BFO), is one of the candidate materials for ferroelectric

memory and electronic device applications. It has two important physical aspects,

ferroelectric and magnetic properties, simultaneously. Recently, many other research groups

were improving the ferroelectric property by texturing effect such as oxide electrode. In this

presentation, the BFO thin films have been deposited by a pulsed laser deposition method on

the Pt/Ti/SiO2/Si substrate with different deposition temperature. Structural and electrical

properties of the thin films were investigated by an x-ray diffractometer and electrical

electrometer to measure leakage currents and ferroelectric properties. It was exhibited that the

hysteresis loop of BFO-P (polycrystalline film) and BFO-T ((111)-textured film) were 64

μC/cm 2 and 128 μC/cm 2 with coercive electric field at 618 kV/cm and 680 kV/cm within

applied electric field at 700 kV/cm.

P- 14


Poster session I

The role of defect-dipole in BiFeO3 thin films

Myang Hwan Lee 1 , Jin Su Park 1 , Da Jeong Kim 1 , Dalhyun Do 1 , Myong-Ho Kim 1 ,

Sang Wook Kim 2 , Hae In Choi 2 , Sang Su Kim 2 , Won Jeong Kim 2

and Tae Kwon Song 1*

1 School of Nano and Advanced Material Engineering, Changwon NationalUniversity,

Changwon 641-773, Korea

2 Department of Physics, Changwon National University, Changwon 641-773,Korea

* E-mailaddress of the corresponding author : tksong@changwon.ac.kr

Multiferroic BiFeO3 (BFO) thin films are one of the candidate materials for new

functional memory applications. However, BFO have drawbacks, such as a high leakage

current density and poor ferroelectric properties often observed in BFO thin films because of

defects and chemical nonstoichiometry. In order to improve the leakage current and

ferroelectric properties, substitutions of Bi to lanthanides and/or Fe to 3d transition metals

have been extensively investigated.

In this work, the Bi1.05(Fe0.99R0.01)O3 (R=Mn 2+ , Zn 2+ , Mn 4+ , and Ti 4+ ) films were

deposited on Pt(111)/Ti/SiO2/Si(100) substrates by pulsed laser deposition. The effects of the

substitution of ions with different oxidation states on ferroelectric and leakage current

properties of those films will be discussed.

P- 15


Poster session I

Flexoelectric Reversal of Polarization in Epitaxial BiFeO3 Films

Byung Chul Jeon 1* , Daesu Lee 1 , Tae Heon Kim 1 , Sang Mo Yang 1 , Myang Hwan Lee 2 ,

Yong Su Kim 1 , Tae Kwan Song 2 , Jong Gul Yoon 3 , Jin Suk Jeong 4 and Tae Won Noh 1

1 ReCFI, Department of Physics and Astronomy, Seoul National University, Seoul 151-747

2 School of Nano and Advanced Materials Engineering, Changwon National University,

Changwon 641-773

3 Department of Physics, University of Suwon, Hwaseong, Gyunggi-do 445-743

4 Department of Physics, Soongsil University, Seoul 156-743, Korea

* E-mail address of the corresponding author : redwolfy@gmail.com

The exploration of strain for modifying and improving physical properties of thin films

is the aim of strain engineering, which has by now become a very popular discipline. Of equal

interest but generally more overlooked is the fact that strain gradients can also affect

functional properties, through the mechanism of flexoelectricity. Owing to their universal

nature, strain gradients and flexoelectricity have been already shown to have important effects

on various material systems. The vertical and horizontal direction of strain gradients generate

a horizontal flexoelectricity that forces the spontaneous polarization to rotate away from the

normal. [Nat. Mater. 16, 963 (2011)] Furthermore, Lee at al., were realized the giant

flexoelectric effect in epitaxial HoMnO3 thin films. It was proposed that flexoelectric effect

should be the intrinsic effect in all dielectric materials. [Phys. Rev. Lett. 105, 127601 (2010)]

In this presentation, we demonstrate the flexoelectric effect (strain gradient induced

polarization) in BiFeO3 films. We synthesized the fully-strained and -relaxed BiFeO3 films on

vicinal SrTiO3(001) films along the [010] direction varying the deposition temperatures. In

the published literatures, as-grown polarization direction in BiFeO3 films is downward. [Adv.

Mater. 19, 2662 (2007), Nat. Mater. 28, 309 (2010)] As-grown polarization direction for

fully-relaxed (-strained) BiFeO3 film is upward (downward). Flexoelectric field is generated

by these relaxation (strain gradient), which reversed the as-grown polarization direction. The

origin of self-poling effect in BiFeO3/SrRuO3 geometry film might be explained by

flexoelectric effect.

P- 16


Poster session I

Morphology studies of poly(vinylidene fluoride-trifluoroethylene)

copolymer films

Hyeon Jun Lee 1 and Ji Young Jo 1*

1 School of Materials Science and Engineering, Gwangju Institute of

Science and Technology, Gwangju 500-712

* E-mail address of the corresponding author : jyjo@gist.ac.kr

Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer is a highly

ferroelectric organic material with origin of ferroelectricity arising from crystalline beta phase.

Ferroelectric phase of P(VDF-TrFE) can be achieved by annealing at the temperature higher

than Curie temperature, which leads to rough morphology due to nano-rods structure and

voids during crystallization process. Rough morphology has been reported to result in

degradation of ferroelectric properties. However, there have been rare studies to improve the

roughness of P(VDF-TrFE) films yet. In this study, we developed experiment method to

improve morphology of P(VDF-TrFE) thin films using double coating method.

P(VDF-TrFE) thin films are firstly coated on indium tin oxide/ glass substrates using

spin coating technique. After the annealing at 120℃, the sample soaked in P(VDF-TrFE)

solution at various temperature and time is spin-coated again. Double coated samples show

increase of diameter of nano-rods and consequently decrease of the size of void. We found

that surface roughness of a double-coated sample in root mean square value is improved by

up to 3 times than that of single coated sample.(20 nm to 6 nm) In this presentation, we will

discuss the ferroelectric properties related to the morphology of P(VDF-TrFE) thin films.

P- 17


Poster session I

Measurement of transverse piezoelectric coefficient in the of

Bi0.5(Na0.82K0.18)0.5TiO3 lead-free films

Song A Chae, Chang Won Ahn, Kang Ho Choi and Ill Won Kim *

Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan,

Ulsan, South Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

The most widely used piezoelectric materials are lead oxide based Pb(Zr,Ti)O3 (PZT)

materials. PZT material exhibits high piezoelectric properties close to a morphotropic phase

boundary (MPB) between rhombohedral and tetragonal phases. Nevertheless, the most used

PZT materials can contain up to 60% lead by weight ratio. Due to the high toxicity of lead,

there is significant interest in developing lead-free piezoelectric materials. Lead-free

piezoelectric materials exhibiting superior electromechanical responses have been formulated

near the MPB region. Among the lead-free piezoelectric materials so far developed, the

binary (1-x)BNT-xBKT (BNKT) class of materials has received considerable attention due to

its excellent ferroelectric and piezoelectric properties near the rhombohedral-tetragonal MPB

with 0.16≤ x ≤ 0.20.

The main hindrance of BNKT thin films fabrication is the loss of stoichiometry because

K is very sensitive to humidity and easy to volatilize during the thermal process. In this study,

we have deposited Bi0.5(Na0.82K0.18)0.5TiO3 thin films having submicron meter thickness on

Pt(111)/TiO2/SiO2/Si(100) substrates by using the chemical solution deposition method. This

films were annealed from 700 to 750 o C for 1 h in the oxygen atmosphere to convert

amorphous to BNKT phase. We have investigated the effect of various excess (10 ~ 140

mol%) of K in precursor solution by measuring on the surface morphology, crystal structure

and transverse piezoelectric coefficient.

P- 18


Poster session I

Electrical Properties of Compositionally Modulated Ferroelectric

Pb(Zr,Ti)O3 Multilayer Films

Sung Min Seo and Jong-Gul Yoon

Department of Physics, University of Suwon, Hwaseong 445-743, Korea

* E-mail address of the corresponding author : jgyoon@suwon.ac.kr

We investigated electrical properties of ferroelectric Pb(Zr,Ti)O3 (PZT) multilayer films

of which the layers had different Zr/Ti ratios and thicknesses. The compositionally

modulated PZT multilayer films were prepared by chemical solution deposition. Since the

electrical properties of PZT material, such as remnant polarization and coercive

fields, strongly depend on the Zr/Ti ratio, the compositional modulation in the multilayer

films may have discontinuity in the electrical properties at the interfaces and induces their

unique characteristics. Polarization-voltage hysteresis loop and capacitance-voltage

characteristics of the compositionally modulated multilayer films were compared with those

of conventional films of uniform composition. The compositionally modulated multilayer

films showed better electrical characteristics, such as higher remnant polarization, lower

coercive fields and higher dielectric responses, than those of single layer films. We will

discuss the electrical properties and usefulness of the compositionally modulated ferroelectric

films.

P- 19


Poster session I

Studies on photovoltaic effect of PZT thin film capacitors depending on Zr/Ti

ratio

Chang Jo Han 1 and Ji Young Jo 1*

1 School of Materials Science and Engineering, Gwangju Institute of Science and Technology,

Gwangju 500-712, Korea

* E-mail address of the corresponding author: jyjo@gist.ac.kr

Ferroelectric thin films offer the opportunities for photovoltaic devices because internal

electric field arising from remnant polarization contributes to flow of photocurrent under

exposure to light. Pb(Zr,Ti)O3 (PZT) exhibits the highest remnant polarization value which

dramatically changes depending on Zr/Ti ratio. The Zr/Ti ratio is well known to affect the

structural/electrical properties of PZT thin films including grain size, orientation, coercive

voltage, and dielectric constant as well as remnant polarization. However, there have been

few studies on how these properties affect photovoltaic effect systematically. Here, we report

the relationship between photovoltaic effect and Zr/Ti ratio.

PZT thin films were deposited on indium tin oxide/glass substrates using spin coating

method. With the Zr/Ti ratio in a range from 20/80 to 80/20, sol–gel solutions were prepared

with lead acetate tri-hydrate [Pb(CH3CO2)2-3H2O], zirconium n-propoxide [Zr(C3H7O)4(n-

propoxide)], and titanium isopropoxide [((CH3)2CHO)4(i-Ti)] precursors by dissolving in 2-

methoxyethanol [CH3OCH2CH2OH] solvent. In order to measure electrical properties, Pt top

electrodes were deposited using e-beam evaporator. Structural properties of PZT thin films

were characterized using x-ray diffraction technique. In this presentation, we will discuss the

photovoltaic properties of PZT thin film capacitors in a function of Zr/Ti ratio.

P- 20


Poster session I

Effects of Concentration of Multi-walled Carbon Nanotube (MWCNT) on

Electrical Properties of MWCNT�Pb(Zr0.52Ti0.48)O3 Composite Films

Jin Kyu Han, Jin Ho Kwak and Sang Don Bu *

Department of Physics, Chonbuk National University, Jeonju 561-756, Korea

* E-mail address of the corresponding author: sbu@chonbuk.ac.kr

Conductive fillers such as multi-walled carbon nanotubes (MWCNTs) have attracted

extensive attention for their electrical properties. The incorporation of the fillers into oxide

materials provides available opportunities for attaining composite with high dielectric

constant, conductivity. According to the literature, the incorporation of MWCNT in

ferroelectric thin film can lead to an improvement of the electron mobility and interface

polarization between the MWCNT and the films. They can result in promoted dielectric

constant of the film.

We report the effects of concentration of the MWCNT on the electrical properties of

Pb(Zr0.52Ti0.48)O3 (PZT) in a film structure. The MWCNT�PZT films were prepared by using

a sol-gel process, spin-coating method, and rapid thermal annealing process. The MWCNT is

purified using a heat and an acid treatment to remove metal impurities and simultaneously to

enhance the dispersion of MWCNT in the solution. The purified MWCNT bundles were

mixed with PZT sol-gel solution of 1 wt% to 30 wt% concentration by a ultrasonic dispersion

method. The MWCNT�PZT solution was deposited onto (111) Pt/Ti/SiO2/Si substrates by

spin-coating with 3000 rpm for 60 s and then they were pyrolyzed. They are annealed at high

temperatures of 500�700 o C in a nitrogen atmosphere. The morphological, structural,

electrical properties of MWCNT�PZT composite films are studied with field-emission

scanning electron microscope, x-ray diffraction, TF Analyzer and HP 4194A impedance

analyzer. The variation of electron mobility and dielectric constant with the increase of

MWCNT in MWCNT-PZT composite films will be discussed.

P- 21


Poster session I

Structure and electrical properties of Ba(Zrx,Ti1-x)O3 thin films by reactive

sputtering method using metallic target

J.W. Kim 1 , H. Funakubo 2* , H. Shima 1 , K. Nishida 1 and T. Yamamoto 1

1 Dept. of communications Eng., National Defense Academy, Kanagawa 239-8686, Japan

2* Dept. of Engineered Materials, Tokyo Institute of Tech., Kanagawa 226-8503, Japan

* E-mail address of the corresponding author : em50059@nda.ac.jp

Barium Titanate (BaTiO3) and perovskite materials are typical ferroeletric material

which have been widely used for various electronic devices. Especially, Ba(Zrx,Ti1-x)O3(BZT)

has been chosen in the fabrications of ceramic capacitors because Zr 4+ is chemically more

stable than Ti 4+ 1) . Moreover, it is reported that the increase in the Zr content decrease grain

size and dielectric constant 2) . Recently, since the size of electronic devices are decreased,

application of film form is extensively investigated. BZT thin films were generally obtained

by sputtering method using ceramics target. But it is difficult to control the composition of the

films in case of ceramics target. Then, we applied the reactive sputtering method for preparing

BZT thin films using a metal target. The BZT thin film can be easily controlled by changing

the Ba, Zr and Ti metal target area ratio. In this study, BZT thin films were grown by

sputtering system using metal target and their characteristics were investigated.

The BZT thin films were deposited on (100)MgO and (100)Pt/(100)MgO substrate by a

RF magnetron reactive sputtering method using metal targets. XRD and XRF was carried out

to investigate the crystallinity and composition of BZT thin films. The surface morphology

and domain structure of the BZT thin films were investigated with AFM and PFM. The

electrical properties of the BZT thin films were measured by ferroelectric test system.

Figure 1 shows P-E hysteresis loops for BZT films

80

with different Zr contents and schematic drawing of metal

60

Zr = 0%

target. It was possible to control the films by changing the

40

20

Zr = 30%

metal targets area ratio. Moreover, it was found that all the

0

Zr = 40%

films were only (001)/(100) orientated and the ratio of -20

Ba/Ti was stoichiometry. It reveals that high quality BZT

-40

-60

films were obtained with different Zr contents using metal

target. We are going to discuss about the results of surface

-80

morphology, electrical properties and these characteristic

Electric field (kV/cm)

Fig. 1. P-E hysteresis loops for BZT films

of other BZT thin films on various substrates.

with different Zr contents

References :

1) B.L. Cheng et al., J. Eur. Ceram. Soc. 25 (2005) 2295–2298.

2) J.W. Zhai et al., Appl. Phys. Lett. 84 (2004) 3136–3138.

P- 22

Polarization(�C/cm 2 )

-3000 -2000 -1000 0 1000 2000 3000


Poster session I

Fabrication of Orientated (Na0.5K0.5)NbO3-BaZrO3-(Bi0.5Li0.5)TiO3 Thin

Films on LaNiO3/SiO2/Si Substrates by Pulsed Laser Deposition

T. Nakao 1,* , M. Fukada 1 , S. Yamazoe 1,2 , T. Wada 1, K. Komaki 3 and H. Adachi 3

1 Department of Materials Chemistry, Ryukoku University, Japan

2 Department of Chemistry, School of Science, The University of Tokyo, Japan

3 Panasonic Corporation, Japan

* E-mail address of the corresponding author : t12m082@mail.ryukoku.ac.jp

Wang et al. reported that 0.92(Na0.5K0.5)NbO3-0.06BaZrO3-0.02(Bi0.5Li0.5)TiO3 (NKN-

BZ-BLT) ceramics showed a large d33 of 420 pC/N. We successfully fabricated NKN-BZ-

BLT thin films on Pt/(001)MgO [1] and (100)Pt/Ti/SiO2/(111)Si substrates [2] by pulsed laser

deposition (PLD). In this study, we fabricated NKN-BZ-BLT thin film on Si substrate with an

LaNiO3 (LNO) layer as a bottom electrode.

We deposited NKN-BZ-BLT films in the following conditions: laser repetition rate 10

Hz, O2 partial pressure about 225 mTorr, substrate temperature 800°C, and 300,000 laser

shots. The crystalline structures of the films were measured by �/2� X-ray diffraction analysis.

The P-E hysteresis loops were observed using a ferroelectric tester. Figures 1 shows X-ray

diffraction patterns of (a) LNO/SiO2/Si substrate, (b) NKN-BZ-BLT film on LNO/SiO2/Si

and (c) NKN-BZ-BLT film on (111)Pt/Ti/SiO2/(100)Si substrates. In Fig. 1 (a), we observe

100 and 200 LNO peaks at 23.3 and 47.5 o , respectively. The LNO layer has a 100 preferred

orientation. In Fig. 1 (b), we observe strong 100 and 200 NKN-BZ-BLT peaks at around 22.6

and 45.9 o , respectively. This NKN-BZ-BLT film has (100) preferred orientation. The pseudotetragonal

lattice constants of NKN-BZ-BLT (ap = 3.979Å and cp = 3.993Å) are larger than

that of LNO (ap = 3.842Å as pseudo-cubic). In Fig. 1 (c), we can observe a 110 NKN-BZ-

BLT peak as well as 100 and 200 peaks. Figure 2 shows the P-E hysteresis of NKN-BZ-BLT

thin films fabricated on LNO/SiO2/(100)Si substrate. This film showed ferroelectric behavior,

and remanent polarization Pr is 1.8 �C/cm 2 .

[1] S. Yamazoe et al., Jpn. J. Appl. Phys., 49, 09MA06 (2010), ibid, 50, 09N

Intensity (cps) Intensity (cps) Intensity (cps)

10 6 10 0

10 1

10 2

10 3

10 4 10 0

10 1

10 2

10 3

10 4

10 4

10 2

100 NKN-

BZ-BLT

100 NKN-

BZ-BLT

100 LNO

110 NKN-

BZ-BLT

200 NKN-

BZ-BLT

(b)

10 0

10 15 20 25 30 35 40 45 50 55 60

2� (degrees)

Fig. 1 X-ray diffraction patterns of (a) LaNiO3(LNO)

/SiO2/Si substrate and (b) NKN-BZ-BLT film on

LNO/SiO2/Si and (c) NKN-BZ-BLT film on

(111)Pt/Ti/SiO2/(100)Si substrates.

111 Pt

SiO 2

200 LNO

200 NKN-

BZ-BLT

(a)

(c)

P- 23

Polarization / �C cm -2

5

4

3

2

1

0

-1

-2

-3

-4

-5

-400 -200 0 200 400

Applied electric field / kV cm -1

Fig. 2 P-E hysteresis loop of NKN-BZ-BLT film

fabricated on LaNiO3(LNO)/SiO2/Si substrate.


Poster session I

(Ag,Li)NbO3 thin films fabricated on (001), (110), and (111)SrTiO3

substrates by pulsed laser deposition

Yu Yamamoto 1 *, Seiji Yamazoe 1,2 and Takahiro Wada 1

1 Department of Materials Chemistry, Ryukoku University, Japan

2 Department of Chemistry, School of Science, The University of Tokyo, Japan

* E-mail address of the corresponding author : t12m093@mail.ryukoku.ac.jp

AgNbO3 (AN) has attracted attention as a lead-free material. We have successfully

fabricated AN films on (001), (110), and (111)SrTiO3 (STO) substrates by pulsed laser

deposition (PLD) [1]. The films showed different dielectric and ferroelectric properties

depending on crystal orientation of STO substrates. In this work, we fabricated (Ag1xLix)NbO3

(ALN) thin films with x= 0.05 and 0.10 on (001), (110), and (111)STO substrates

by PLD.

Before deposition of the ALN film, we deposited SrRuO3 (SRO) film as a bottom

electrode on (001), (110), and (111) STO substrates. Then, we deposited ALN films with a

thickness of 2~4 �m. The fabrication conditions were as follows: laser repetition rate 10 Hz,

target and substrate distance 90 mm, O2 partial pressure about 225 mTorr, substrate

temperature of 700°C, and 750,000 laser shots. The crystalline structures of the ALN films

were measured by θ/2θ X-ray diffraction analysis. To characterize the surface morphologies,

the surfaces were observed by SEM. The relative dielectric constant εr and dielectric loss tanδ

were measured by an LCR meter, and P-E hysteresis loops were observed using a

ferroelectric tester.

X-ray diffraction (XRD) showed that ALN(x=0.05, 0.10) films were epitaxially grown

on (001), (110), (111) STO substrates. The diffraction peaks of the ALN films shifted to

higher angle with increasing Li concentration, x. Figures 1 show SEM surface micrographs of

the ALN films deposited on (001), (110), and (111) STO substrates. The figures clearly show

that the surface textures of the ALN films are different by the crystal orientation of the STO

substrate. The ALN film on (001)STO has a smooth surface with several square holes. The

film on (110)STO has a striped pattern, and that on (111)STO has a trigonal pyramid-like

structures. We reported similar microstructures for AN [1] and NaNbO3 [2] films fabricated

on the (001), (110), and (111) STO. The P-E hysteresis showed that the ALN(x=0.1) film on

(111) STO exhibited a ferroelectric behavior and had the largest remanent polarization (Pr) of

40 �C/cm 2 of all the ALN films.

[1] H. Sakurai, S. Yamazoe, and T. Wada, Appl. Phys. Lett. 97, 042901 (2010).

[2] S. Yamazoe et. al., Appl. Phys. Lett. 95, 062906 (2009).

(001)SrTiO3 (110)SrTiO3 (111)SrTiO3

Fig. 1 Surface SEM micrographs of (Ag0.9Li0.1)NbO3 thin films deposited on (001), (110) and (111) SrTiO3

substrates.

P- 24


Poster session I

The effect of crystallization process of P(VDF/TrFE) thin film on

the ferroelectric properties

Yoshiki Yachi, Takeshi Yoshimura, Atsushi Ashida and Norifumi Fujimura

Graduate School of Engineering, Osaka Prefecture University

1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan

* E-mail address of the corresponding author : tyoshi@pe.osakafu-u.ac.jp

Poly(vinylidene fluoride/trifluoroetylene)[P(VDF/TrFE)] has attracted a great deal of

attention in recent years due to the potential for device applications such as micro sensors and

actuators. P(VDF/TrFE) have a Curie temperature (Tc) between 100-130℃, which depends

on the composition. 1 For P(VDF/TrFE) thin films, annealing treatment is usually employed

for the crystalization 2 . In this study, P(VDF/TrFE) films are prepared at different annealing

temperatures and the relationship between the structure and ferroelectric properties is

investigated.

P(VDF/TrFE) with a composition 75/25 mol% was deposited by a spin cast method on

Pt/Ti/SiO2/Si substrates. Methyl ethyl ketone was used for the solvent. The films were

annealed between 40 and 140 o C. Al top electrodes were deposited on the films. The

crystallization of the films was investigated by X-ray diffraction (XRD). Fig. 1 shows the

annealing temperature dependence of the XRD integral intensity of the (200), (110)

diffraction and the remnant polarization (Pr). The results indicate that the films crystalize by

the annealing above 100 o C. On the other hand, Pr increases at the annealing temperature of

130~140 o C (above the Tc). Thus the annealing temperature to improve the ferroelectric

properties is different from the crystallization temperature. It is suggested that the increase of

Pr is caused by the annealing above the Tc. In parraelectric phase, molecular chain rotates

around the chain axis and is quite mobile along it. 2 Therefore, it can be expected that the

annealing in the paraelectric phase enhances

the realignment of the molecular chain,

which leads to the improvement of the

ferroelectric properties of P(VDF/TrFE).

Reference

Fig.1 Annealing temperature dependence of

XRD integral intensity (triangle) and Pr

(square)

P- 25

1 T. Furukawa, Phase Trans. 18, 143 (1989).

2 H. Ohigashi et al., Appl. Phys. Lett. 66, 1079

(1995).


Poster session I

Effects of La substitution for BiFeO3 epitaxial thin films

K. Wakazono, Y. Kawahara, K. Ujimoto, T. Yoshimura and N. Fujimura

Graduate School of Engineering, Osaka Prefecture University

1-1 Gakuen-cho, Nakaku, Sakai, Osaka,599-8531, Japan

* E-mail address of the corresponding author : tyoshi@pe.osakafu-u.ac.jp

Recently, BiFeO3 (BFO) thin films have been attracted great interest 1 , because BFO is

Pb-free ferroelectric and has large spontaneous polarization (~100 �C/cm 2 ). We have reported

that the direct piezoelectric properties of BFO thin films are comparable to that of PZT thin

films. For the Pb-based ferroelectrics, it is known that the piezoelectric properties increase

with decreasing the Curie temperature. In this study, we fabricated BFO and (Bi0.9, La0.1)FeO3

(BLFO) epitaxial thin films and discuss the effect of La substitution on crystallographic and

electrical properties, because La substitution decreases the Curie temperature.2

BLFO and BFO thin films were grown at 590, 620, 650 ºC and 580, 620, 660 ºC,

respectively, using pulsed laser deposition system on (001) SrRuO3/(001) SrTiO3, the

thickness is about 50 nm. Figure 1 shows the surface morphology of BLFO and BFO thin

films observed by atomic force microscopy. As can be seen, BLFO thin films have smooth

surface than BFO thin films and have less dependence on the deposition temperature. The

crystal structure of the films was investigated by X-ray diffraction 2��� scan and rocking

curve measurement. As shown in Fig.2, BLFO thin films have smaller full width at half

maximum (FWHM) of (003) diffraction peak on the 2��� scan than BFO. Thus, the

crystallinity of the BFO films is improved by La substitution on the A site.

Reference

[1]K.Ujimotoet al.,Appl. Phys. Lett., 100, 102901 (2012)

[2]H.Uchida et al.,J.Appl.Phys.,100,014106 (2006)

Fig. 1 Surface Morphology of BFO thin films deposited at

(a)580 ºC,(b)620 ºC,(c)660 ºC and BLFO thin films

deposited at (d)590 ºC,(e)620 ºC,(f)650 ºC

P- 26

Fig. 2 FWHM of XRD 2��� scan and

rocking curve of (003) diffraction.


Poster session I

Phase transition behaviors in La-doped Bi1/2(Na0.82K0.18)1/2TiO3 lead-free

piezoelectric ceramics

Thi Hinh Dinh 1 , Hyoung-Su Han 1 , Van Quyet Nguyen 1 , Dae-Jun Heo 1 ,

Chang Won Ahn 2 and Jae-Shin Lee 1*

1 School of Materials Science and Engineering, University of Ulsan, Ulsan, Korea

2 Department of Physics, University of Ulsan, Ulsan, Korea

* E-mail address of the corresponding author: jslee@ulsan.ac.kr

This study investigated the phase transition, dielectric, and electromechanical properties

of A-site donor doped [Bi1/2(Na0.82K0.18)1/2]TiO3 (BNKT) ceramics, in which La was selected

as the A-site donor. The bismuth-based perovskite [Bi1/2(Na0.82K0.18)1/2]1-xLaxTiO3 (La100x; x

= 0.00-0.05) were successfully fabricated by conventional solid state method. The effects of

poling process on the crystal structural and dielectric properties of the ceramics were analyzed.

A systematic X-ray diffraction study of poled and unpoled specimens revealed significant

differences in unit cell parameters between them. As the La-doping level increased from 0 to

5 mol%, there happened a phase transition from the coexistence of rhombohedral and

tetragonal phases to a pseudocubic symmetry at x=0.03 for unpoled specimens and at x =0.04

for poled specimens, respectively.

From measurements of temperature dependent dielectric properties, all specimens

showed strong frequency dependent dispersions, which is a symptom of relaxor ferroelectrics.

Although the maximum dielectric constant reached at about 280 o C, a hump at lower

temperature was found for all specimens, which was formerly known as the depolarization

temperature (Td). The Td shifted down as the La-doping level increased. Interesting was that a

large electric-field-induced strain was observed when the La content reached 3 mol% as

reported in previous studied on B-site donor doped BNKT ceramics. This presentation will

discuss the nature and electrical properties of phases observed in La-doped BNKT ceramics.

P- 27


Poster session I

Low Frequency Dielectric Dispersion and Conduction Behaviors of BaTiO3

modified Na0.5Bi0.5TiO3 Ferroelectric Ceramics

J. S. Kim 1* , A. Hussain 1 , G. H. Ryu 1 , M. H. Kim 1 , T. K. Song 1 and W. J. Kim 2

1 School of Nano & Advanced Materials Engineering, Changwon National

University, Gyeongnam 641-773, Korea

2 Department of Physics, Changwon National University, Gyeongnam 641-773,

Korea

* E-mail address of the corresponding author : kimjjin@changwon.ac.kr

The ferroelectric and electrical properties of Bi0.5Na0.5TiO3 (BNT) based ceramics have

been extensively investigated. However, limited attention has been paid to ion doping effect

of these materials. To investigate the effect of ion doping on dielectric and ferroelectric

behaviors of lead free Bi0.5Na0.5TiO3 based ferroelectric ceramics, we prepared BaTiO3

modified Bi0.5Na0.5TiO3 (BNT:BT) ceramics by a solid-state reaction method. The crystallized

phase and grain morphology of the BNT:BT ceramics were confirmed by X-ray diffraction

and scanning electron microscopy (SEM) studies, respectively. The BaTiO3 doping

influenced the structural phase transition, dielectric properties and ferroelectric behaviors.

With increasing BaTiO3 doping, the phase transition temperature (TR-T, i.e phase transition

from the rhombohedral to the tetragonal symmetry) shifted to low temperature and the

dielectric peak was broad. On the other hand, the dielectric peak depended on the measuring

frequency and shifted to the higher temperature, which indicates a ferroelectric relaxor likebehavior.

The substitution of BaTiO3 affects the degree of disorder in crystallographic A sites

in (A,B)O3 perovskite structure. In addition, we studied the effects of ion doping on

ferroelectric, dielectric dispersion and conduction behaviors in detail.

P- 28


Poster session I

Low Frequency Optical Phonons in SrTiO3 under Uniaxial Stress

Yuhji Tsujimi * and Tomori Yanagisawa

Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan

* E-mail address of the corresponding author : yts@es.hokudai.ac.jp

Strontium titanate SrTiO3 is known to have the quantum paraelectric state (QPS) below

about Tq = 37 K.[1] It has been reported from Raman scattering and SHG experiments that the

transition from the QPS to the quantum ferroelectric state (QFS) is caused by the application

of uniaxial stress.[2, 3] In order to understand the dynamical mechanism of the transition, we

have performed the 180 o light scattering experiment with a scattering vector of q // [001]c and

observed the ferroelectric Eu(x, y) soft mode (FE mode) under the uniaxial stress ���along the

[010]c direction). The size of the sample was 2.0[100]c �1.65 [010]c�4.1[001]c mm 3 .

Figure shows the frequency shift (��: left panels) and line width (��: right panels) of the

FE mode as a function of �. Upper, middle and lower panels correspond to the experimental

results obtained at T = 5.0, 10.3, and 16.5 K, respectively. Yamanaka et al. measured ��

(only) under the atmospheric pressure by using a Hyper Raman scattering method.[4] Their

results are presented in the figure by symbols ( ). Combining their results and ours, we can

state that the FE mode does not soften completely even at critical stresses � c (7±1, 8±1, and

13±1 kg/mm 2 at T = 5.0, 10.3, and 16.5 K, respectively). Moreover, �� clearly increases near

� c. Especially, �� takes the maximum value at around � c at T = 16.5 K. Basing on these

results, we discuss the similarities between the QPS-QFS transition of SrTiO3 and that of

SrTi 18 O3.

We also present our finding that the intensity of the spectral peak (which is characteristic

of the QPS and is called “broad doublet”

(BD) [5]) drastically increases near � c

~13±1 at T = 16.5 K. This fact clearly

indicates that the BD must be the mode

related with the critical phenomena.

[1] K.A.Müller and H.Burkard, PRB 19

(1979) 3593. [2] H.Uwe and T.Sakudo;

PRB 13 (1976) 271. [3] Y.Fujii et al.;

JPSJ 56 (1987) 1940. [4] A.Yamanaka et

al.: Europhys. lett. 50 (2000) 688. [5]

B.Hehlen et. al.; PRL 75 (1995) 2416.

P- 29


Poster session I

Temperature-Field Phase Diagrams in Pb(Zn1/3Nb2/3)O3-8%PbTiO3

Makoto Iwata 1* , Sadaharu Kato 1 , Kazuki Tanaka 1 , Masaki Maeda 1

and Yoshihiro Ishibashi 2

1 Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan

2 Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan

* E-mail address of the corresponding author : miwata@nitech.ac.jp

It is known that solid solution of 92%Pb(Zn1/3Nb2/3)O3-8%PbTiO3 (PZN-8%PT) near the

morphotropic phase boundary (MPB) show giant dielectric and piezoelectric responses. It was

claimed that such giant responses essentially come from the transversal instability near MPB

on the basis of the Landau-type free energy, where the dielectric constant perpendicular to the

spontaneous polarization becomes extremely large because anisotropy of the free energy in

the parameter space becomes small. 1)

It was reported that the critical end point (CEP) appears under the DC electric field in a

related material Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), and was pointed out that the giant

electromechanical response in PMN-xPT is the manifestation of CEP in addition to the

physical property of MPB. 2) On the basis of the Landau-type free energy function, anisotropy

of dielectric properties and temperature-field phase diagrams were qualitatively explained. 3)

In our previous study, we reported our experimental results of the DC field dependence of the

dielectric constant as a function of temperature in the [001]-direction of PZN-8%PT, and

clarify the temperature-field phase diagram. 4-6)

In the present study, we have investigated the DC field dependence of the dielectric

constant as a function of temperature in the (001)-, (011)-, and (111)-plates of PZN-9%PT.

The temperature-field phase diagrams along these directions have been clarified. It has been

found that the tetragonal phase disappears under the electric field above 10 kV/cm along

[011]- or [111]-direction. It is pointed out that, on approaching CEP, both the energy cost and

the electric field required to induce the rotation of the spontaneous polarization remarkably

decrease. This will explain the giant electromechanical response in PZN-xPT as Kutnjak et al.

proposed. 2) Nature of the phase transition based on our experimental results has been also

discussed.

1. Y. Ishibashi and M. Iwata: Jpn. J. Appl. Phys. 37 (1998) L985.

2. Z. Kutnjak, J. Petzelt, and Blinc: Nature 441 (2006) 956.

3. M. Iwata, Z. Kutnjak, Y. Ishibashi and R. Blinc: J. Phys. Soc. Jpn. 77 (2008) 034703.

4. M. Iwata, K. Sakakibara, R. Aoyagi, M. Maeda, and Y. Ishibashi: Ferroelectrics 405

(2010) 39.

5. M. Iwata and Y. Ishibashi: Phase Transitions 84 (2011) 753.

6. M. Iwata, S. Kato, and Y. Ishibashi: Ferroelectrics 415 (2011) 20.

P- 30


Poster session I

Charge density study of BiFeO3-PbTiO3 solid solution system with large

tetragonal lattice distortion

Kazuaki Taji 1* , Chikako Moriyoshi 1 , Yoshihiro Kuroiwa 1 , Hiroki Moriwake 2 ,

Shuvrajyoti Bhattacharjee 3 and Dhananjai Pandey 3

1 Department of Physical Science, Hiroshima University, Hiroshima 739-8526, Japan

2 Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8526, Japan

3 School of Material Science and Tech., Banaras Hindu University, Varanasi-221005, India

* E-mail address of the corresponding author : tajikazuaki@hiroshima-u.ac.jp

The solid solution system (1-x)BiFeO3-xPbTiO3 (BF-xPT) has attracted wide attention

due to the multiferroic properties. Recently we have found that the tetragonal-tetragonal

isostructural phase transition takes place near the morphotropic phase boundary (MPB) in BFxPT

[1]. For example, BF-0.31PT with large tetragonal lattice distortion c/a = 1.187 at RT

undergoes the phase transition to the cubic phase at high temperature through the other

isostructural tetragonal phase with less tetragonal lattice distortion. The curious phase

transition is originated from the extraordinarily large lattice distortion which cannot be

observed other perovskite-type solid solutions such as PZT and PMN-PT. In this study, we

have carried out the crystal structure analysis at the charge density levels in BF-xPT system to

reveal the origin of the large tetragonal lattice distortion by analyzing synchrotron radiation

powder diffraction data measured at SPring-8 BL02B2 using the MEM/Rietveld method.

We have found that the large tetragonality of this system is characterized by shortening

of Bi/Pb-O bonding, elongation of Fe/Ti-O bonding, and decreasing of O-Fe/Ti-O angle with

decreasing composition x in the tetragonal phase. The other bond lengths are nearly constant.

The characteristic chemical bondings, that are Fe/Ti in 5-fold O coordination and covalent

Bi/Pb-O bonding, are clearly visualized in the MEM charge density map in the entire

tetragonal composition range x > 0.31 at RT. In BF-0.31PT, significantly higher bonding

electron density is observed on the Bi/Pb-O and Fe/Ti-O bonds. The oxygen polyhedron can

be regarded as an Fe/Ti-O5 pyramid rather than an Fe/Ti-O6 octahedron. Hence, we consider

that the large tetragonal lattice distortion in BF-xPT solid solution system is originated from

the doping effect of the Bi ion to form the Bi-O electron orbital hybridization which involves

a layered structure in the tetragonal phase at RT.

[1] S. Bhattacharjee, K. Taji, C. Moriyoshi, Y. Kuroiwa, and D. Pandey, Phys. Rev. B 84,

104116 (2011).

P- 31


Poster session I

Electric-field-induced phase transition of BaTiO3-based ceramics

Mayuko Ogawa 1* , Chikako Moriyoshi 1 ,Yoshihiro Kuroiwa 1 ,

Noriyuki Inoue 2 and Takafumi Okamoto 2

1 Department of Physical Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima,

Hiroshima 739-8526, Japan

2 Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto 617-8555, Japan

* E-mail addressof the corresponding author:mayuko-ogawa@sci.hiroshima-u.ac.jp

BaTiO3, one of perovskite-type ferroelectrics, is applied to multilayer ceramic capacitors

(MLCCs) as a dielectric material. To satisfy requirements for the lower dielectric loss and

lower microphonics, rare-earth Rand Mg ions co-substituted BaTiO3 ceramics are proposed as

candidates for the dielectrics. This co-substitution enables us to suppress various problems

involved in applying the dielectric properties of pure BaTiO3 to MLCCs. Gd and Mg cosubstituted

(Ba0.94Gd0.06)(Ti0.97Mg0.03)O3 (BGTM) is a promising material in respect of

suppressing the insulation degradation[1]. The aim of our study is to clarify the relationship

between the electric polarization and crystal structure of BGTM in the environments realizing

the electric device operating. In this paper, we demonstrate in situ lattice strain observation of

BGTM under variations of temperature and external electric field using a sample fabricated

based on MLCC by synchrotron radiation diffraction.

Powder diffraction patterns of BGTM were measured by the large Debye-Scherrer

camera installed at BL02B2 in SPring-8. We used the high-energy X-rays of 35 keV (��= 0.35

Å) to investigate the inside of the sample in the transmission geometry. The lattice strain of

BGTM was observed in the temperature range of T = 200–400 K and the electric-field range

of E = 0 –300 kV/cm.

The first order phase transition which involves a discontinuous change in the lattice

strain was observed in BGTM at TC = 293 K, without applying electric field. When the

electric field was applied just above TC, the electric-field-induced phase transition took place

with an abrupt change in the lattice strain. The change turned out gradually when the electric

field was applied far above TC. We propose the E-T phase diagram of BGTM with the critical

point (Ecrit, Tcrit).

[1] N. Inoue, T. Okamatsu, A. Ando, H. Takagi, T. Hashimoto, C. Moriyoshi, and Y.

Kuroiwa: Jpn. J. Appl. Phys. 48, 09KF03 (2009).

P- 32


Poster session I

Structural characteristics of Ca-substituted BaTiO3 in cubic phase by high

energy synchrotron radiation powder diffraction

Shoichi Takeda 1* ,Chikako Moriyoshi 1 , Eisuke Magome 1 , Yoshihiro Kuroiwa 1

and Jun Ikeda 2

1 Graduate School of Science, HiroshimaUniversity, Kagamiyama, Higashi-Hiroshima,

Hiroshima 739-8526, Japan

2 Murata Manufacturing Co., Ltd., Nagaokakyo, Kyoto 617-8555, Japan

* E-mail address of the corresponding author : shoichi-takeda@hiroshima-u.ac.jp

In the Ca-substituted BaTiO3 system (Ba1-xCax)TiO3 (BCT), the phase transition

temperatures show nonlinear variations with the Ca-composition x; the cubic-tetragonal phase

transition temperature TC C-T is rather constant but which shows a relevant maximum TC C-T =

407 K at x= 0.06, while both the tetragonal-orthorhombic and orthorhombic-rhombohedral

phase transition temperatures, TC T-O and TC O-R , respectively decrease dramatically with

increasing x, and the tetragonal phase is emerged as the most stable phase at low temperatures

in the composition region of x > 0.23 [1], which makes a strong contrast with a linear

variation of the lattice constant a in the cubic phase. The ferroelectric phase transitions in

solid solutions can be closely connected with the structural characteristics and the

ferroelectric instability caused in the prototype structure [2]. In this study, we analyzed the

crystal structure of BCT in the cubic phase at the electron density levels to discuss the

characteristics of the crystal structure which control the phase transitions in BCT.

BCT sample powders (x = 0 – 0.20) were synthesized by a conventional solid state

reaction method. Synchrotron radiation powder diffraction data were collected using the large

Debye-Scherrer camera installed at SPring-8 BL02B2. The energy of X-rays was 30 keV

(wave length λ= 0.41 Å). The crystal structure and electron charge density distribution was

analyzed by the maximum entropy method (MEM)/Rietveld method. Subtle but clear

tendency is observed in the electron charge density at the midpoint on the Ti-O bonding

associated with the variation of TC C-T showing a maximum at x ~ 0.06. This result implies the

validity of the orbital hybridization between Ti and O atoms controlling the TC C-T . We will

discuss the change in TC T-O and TC O-R based on the thermal motions of the constituent atoms.

[1] T. Mitsui and W.B. Westphal, Phys. Rev. 105, 1354(1961).

[2] Y. Kuroiwa etal., Jpn. J. Appl. Phys. 44, 7151(2005).

P- 33


Poster session I

Nonpolar Soft Optic Phonon of Cubic-rhombohedral Phase Transition of

LaAlO3 Studied by Inelastic Light Scattering

Yuto Fujita*, Kohei Suzuki, Tae Hyun Kim, and Seiji Kojima

PAS,University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

*E-mail address of the corresponding author : yuto.fuji.4@gmail.com

LaAlO3 undergoes an improper ferroelastic phase transition from the cubic phase (Pm3 _

m) to nonpolar rhombohedral phase (R3 _

c). The main structural difference between the cubic

and rhombohedral phases is the rotation of AlO6 octahedra around one of the triad axes in the

cubic phase [1]. Lattice instability of a cubic- rhombohedral phase transition is studied by

low-frequency Raman scattering in the backward scattering geometry a(cc)a _

using a double

grating spectrometer (U1000) and a green YAG laser as an exciting source. The soft optic

mode in the paraelectric phase has F2u symmetry and is threefold degenerate. It splits into

1A1g and 2Eg modes in the rhombohedral phase. These soft modes are Raman active but

infared inactive. The lowest Eg symmetry mode at 30 cm -1 shows remarkable softening

toward the transition temperature Ttr=540℃ as shown in Fig.1. The elastic anomaly and

central peak are also studied by broadband Brillouin scattering using a tandem-multipass

Fabry-Perot interferometer [2].

Intensity (arb.unit)

3000

2500

2000

1500

1000

500

E g

0

-100 -80 -60 -40 -20 0 20 40 60 80 100

Frequency shift (cm -1 )

P- 34

22 ℃

150 ℃

340 ℃

500 ℃

580 ℃

Fig.1 Temperature dependence of Raman spectra of a LaAlO3 crystal.

References

1. S. A. Hayward et al., Phys. Rev. B 72 (2005) 054110.

2. S. Kojima, Jpn. J. Appl. Phys. 49 (2010) 07HA01.

A 1g


Poster session I

Raman and Brillouin scattering studies on lead-free piezoelectric

Bi0.5(Na0.78K0.22)0.5-xTiO3 ceramics with A-site vacancies

Jae-Hyeon Ko 1* , Tae Hyun Kim 1,2 , Seiji Kojima 2 , Chang Won Ahn 3

and Ill Won Kim 3

1 Department of Physics, Hallym University, Gangwondo 200-702, Korea

2 Graduate School of Pure and Applied Sciences, Univ. of Tsukuba, Ibaraki 305-8573, Japan

3 Department of Physics, University of Ulsan, Ulsan 680-749, Korea

* E-mail address of the corresponding author : hwangko@hallym.ac.kr

The acoustic and optic phonon properties

of piezoelectric Bi0.5(Na0.78K0.22)0.5-xTiO3

ceramics with A-site vacancies of x=0~0.05

(BNKT-A) were investigated by using

Brillouin and Raman spectroscopies at ambient

temperature. These ceramics were located on

the tetragonal side of the phase diagram close

to the morphotropic phase boundary. The

Brillouin spectrum consisted of a distributed

longitudinal acoustic (LA) mode at ~ 50 GHz

and a strong central peak. Since the ceramic

samples were polycrystalline, the scattering

events would occur at all scattering angles due

to multiple refractions and reflections. The

distributed Brillouin doublet of the LA mode

became sharper appreciably when x was larger than

0.015. This result was correlated with the fact that

the density of BNKT-A became a maximum and

was saturated for x ≥ 0.015. It is probable that the

acoustic waves are not perturbed substantially at

grain boundaries due to the high density and more

compact sample condition at high x. Raman spectra

of BNKT-A ceramics exhibited approximately

seven broad peaks over the frequency range of 50 ~

1000 cm -1 , consistent with previous Raman studies

on similar lead-free ceramics. The peak positions

were not sensitive to the concentration of A-site vacancies. The number of peaks was reduced

in the paraelectric phase of BNKT-A.

* This research was supported in part by Basic Science Research Program through the

National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science

and Technology (2010-0010497).

P- 35

Intensity (arb. units)

1500

1000

500

Brillouin

x=0

x=0.005

x=0.01

x=0.015

x=0.02

x=0.03

x=0.04

x=0.05

-60 -40 -20 0 20 40 60

Frequency Shift (GHz)

Raman


Poster session I

Electric and Dielectric Properties of reduced La0.01Ba0.99TiO3

Ahmed I. Ali 1,2 , Abdel Moez 3 and Yong Soo Kim 2*

1 Basic Science Dep., Faculty of Industrial Education, Helwan University, Saray El-Quba,

11281 Cairo, Egypt

2 Dep. of Physics and Energy Harvest-Storage Research Center, University of Ulsan, 680-749

Ulsan, Korea

3 Solid State Physics Dep., Physical Research Division, National Research Center (NRC),

Dokki, Cairo, Egypt.

* E-mail address of the corresponding author: yskim2@ulsan.ac.kr

The technological application of BaTiO3 system has been attracted a great deal of

attention due to its excellent dielectric properties, such as low dielectric loss and low

temperature coefficients of dielectric constants. In this report, the electrical properties -

resistivity and carrier concentration- of reduced La0.01Ba0.99TiO3 were investigated

experimentally in the temperature range (300 K ~ 600 K). The samples were reduced at

1380 °C under around 10 -14 atmosphere of oxygen pressure. While the electrical resistivity

decreased linearly with increasing temperature, carrier concentration was decreased up to 400

K, followed by a rapid increase at higher temperatures. The Hall mobility has peak value

around 380 K and decreased due to increasing charge carrier, which is thermally activated

excess carrier, as temperature increase. In situ high-temperature electrical resistivity and Hall

measurements have proven useful tools for establishing doping effect in perovskite

La0.01Ba0.99TiO3 and to screen it for potential technological applications. The capacitancetemperature

measurement with different frequency shows that the phase transition around 420

K is occurred.

Mobility � (cm 2 /V.s )

0.8

0.6

0.4

0.2

0.0

250 300 350 400 450 500 550

Temperature (K)

(a)

Dielectric constant (�')

Fig. Hall mobility (a), dielectric constant (b) as function of temp. for the reduced La0.01Ba0.99TiO3

P- 36

80

75

70

65

60

1kHz

10kHz

100kHz

300 400 500 600

Temperature (K)

(b)


Poster session I

High piezoelectric coefficient of lead-free KNN-based thin films

for MEMS application

Hae Jin Seog 1 , Sun-Young Lee 1 , Chang Won Ahn 1 , jin Ho Choi 1 , Seung Ho Han 2

and Ill Won Kim 1*

1 Department of Physics and Energy Harvest-Storage Research Center,

University of Ulsan, Ulsan 680-749, Korea

2 Convergence Components R&D Division, KETI, Seongnam 463-816, South Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

Lead-free piezoelectric materials have been receiving special attention due to the recent

environmental issues. K0.5Na0.5NbO3 (KNN) is a promising lead-free candidate material, as it

has a good ferroelectric and piezoelectric properties as well as biocompatibility. Recently,

Saito et al. reported that most of the piezoelectric properties are comparable to those of PZT.

However, densification of KNN ceramics is reported to be difficult. Thin film fabrication of

KNN-based thin film is even more challenging due to added complexity in the process

compared to bulk ceramic fabrication.

We have fabricated Li, Ta and Mn doped KNN thin films on Pt substrates by using the

chemical solution deposition method. Studies about the partial substitution of the Li for A-site

and Ta for B-site atoms in the KNN films were carried out to improve the ferroelectric and

piezoelectric.[1,2] Ta doped KNN films exhibited a well-saturated piezoelectric hysteresis

loop with a effective piezoelectric coefficient (d33,f) value of 61 pm/V. Mn doping effectively

decrease a leakage current density due to reduction of hole conduction. Mn doped KNN film

exhibits d33,f value of 80 pm/V. We are trying to fabricate KNMN cantilever. Therefore, the

KNN-based thin films can be considered as an alternative for PZT films due to its comparable

piezoelectric coefficient.

[1] C. W. Ahn, E. D. Jeong, S. Y. Lee, H. J. Lee, I. W. Kim, Appl. Phys. Lett. 93, 212905

(2008).

[2] S. Y. Lee, C. W. Ahn, J. S. Kim, H. J. Lee, J. S. Choi, B. H. Park, I. W. Kim, J. Alloys and

Comp. 509, L194 (2011).

P- 37


Poster session I

Fabrication and Characterization of Inorganic Organic Composites Using

Ferroelectric Nanoplates

Ryo Kishimoto 1 , Masafumi Kobune 1* , Hiroshi Nishioka 1 , Takeyuki Kikuchi 1 ,

Hajime Kishi 1 , Hironori Fujisawa 1 , Seiji Nakashima 1 , Masaru Shimizu 1

and Satoshi Kimura 2

1 Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-

2201, Japan

2 Seiko Epson Corporation, Fujimi Plant 281 Fujimi, Fujimi-machi, Suwa-gun, Nagano 399-

0293, Japan

* E-mail address of the corresponding author : kobune@eng.u-hyogo.ac.jp

In the present report, the fabrication of ferroelectric Bi3.25Nd0.75Ti3O12 (BNT-0.75)

nanoplate-epoxy resin composites was attempted by introducing epoxy resin to the space

between BNT nanoplates on 3.0-�m-thick BNT(100)/(010) film/Nb:TiO2(101) substrate with

0.79 mass% Nb. a- and b-axis-oriented BNT nanoplates, 3.0 �m thick, were fabricated on

conductive Nb:TiO2(101) substrates with 0.79 mass% Nb at 650 o C by high-temperature

sputtering. The fabricated nanoplates had a good polarization-electric field (P-E) hysteresis

loop shape with a remanent polarization (2Pr) of 29 �C/cm 0 and coercive field (2Ec) of 297

kV/cm. After organic film fabricated on the BNT nanoplates by spin-coating process using

the epoxy resin solution added with an epoxy-curing agent and a catalytic agent, the hardened

film was prepared by curing it in two stages (120 o C, 1 h and 170 o C, 2 h) under vacuum. After

surface grinding to eliminate an extra resin, effective piezoelectric coefficients (d33) and

polarization reversal characteristics of the resulting composites were measured using a

piezoresponse force microscope (PFM) system. Figure 1 shows surface atomic force

microscope (AFM) images of the inorganic-organic composite before and after the

polarization reversal treatment. Figure 1(b) shows that the upper half part in the square was

applied by downward bias of DC 40V to the sample, whereas the lower half part was applied

by upward bias of the same voltage.

Consequently, the polarizationreversed

BNT nanoplates appeared

as some longitudinal black bars in

the lower half part in the square of

Fig. 1(b).

Fig. 1. Surface AFM images of BNT nanoplate-epoxy

resin composite (a) before and (b) after polarization

reversal treatment.

P- 38


Poster session I

Evaluation of switching charge density of PbTiO3 nanoislands by atomic

force microscopy

Masashi Igawa* , Seiji Nakashima, Hironori Fujisawa, and Masaru Shimizu

Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji,

Hyogo 671-2201, Japan

* E-mail address of the corresponding author : er12t002@steng.u-hyogo.ac.jp

We have already reported fabrication and ferroelectric properties of self-assembled

PbTiO3 nanoislands epitaxially grown on Pt electrodes by MOCVD. Piezoresponse force

microscopy (PFM) revealed that piezoelectric coefficient d33 was decreased with their height

less than 10nm. In this study, we evaluated the switching charge density (Qsw) of individual

epitaxial PbTiO3 nanoisland by atomic force microscopy (AFM).

PbTiO3 nanoislands with an average height of 4nm

and width of 55nm were epitaxially grown on Pt/Ir/SrTiO3

substrates by MOCVD, as shown in Fig.1. In our

measurements, a conductive AFM tip was directly

contacted to individual PbTiO3 nanoisland as a top

electrode. A difficulty of AFM measurements of the

switching charge is in that the switching charge is much

smaller than charging and discharging charges to the

parasitic capacitance. In our AFM system, the parasitic Fig.1 AFM image of PbTiO3

capacitance was reduced to be less than 100 fF. Switching nanoislands.

charge was measured by applying a pulse train with a

preceding negative pulse, two consecutive positive pulses

and two negative pulses, as shown in Fig.2. The amplitude

and width were 2V and 400ns, respectively. The charge

Q1 includes charges transferred by both polarization

switching and leakage, and Q2 corresponds to leakage

because polarization was switched by the first pulse and

not by the second one. Therefore, the difference between

Q1 and Q2, Q1-Q2, corresponds to the switching charge,

which was calculated to be 4.9 fC for the nanoisland. The

charge of 4.9 fC corresponds to a switching charge density Fig.2 An applied voltage pulse

train and switching charge

of 135�C/cm2. At the conference, a size dependence of

transient of a PbTiO3 nanoisland

Qsw will also be discussed.

with a height of 3.3nm and a

width of 61×60nm.

P- 39


Poster session I

Magnetoelectric Properties of CuFe2O4/BaTiO3 Bi-layer Thin Films

Dong Jin Yoon 1 , Jungho Ryu 2 , Sung-Ok Hwang 3 , Jai-Yeoul Lee 1

and Hee Young Lee 1 *

1,3 Department of Materials Science and Engineering, Yeungnam University,

Gyeongsan, 712-749, Korea

2 Functional Ceramics Research Group, Korea Institute of Materials Science (KIMS),

Changwon, 641-831, Korea

* E-mail address of the corresponding author: hyulee@yu.ac.kr

Multiferroic properties of CuFe2O4/BaTiO3 thin films grown on highly textured

Pt(111)/TiO2/SiO2/Si(100) substrates were studied. Sintered BaTiO3 and CuFe2O4 pellets

prepared by the conventional mixed oxide process were used as targets during deposition by

the ion-beam sputtering and the pulsed laser deposition technique. The film structure is of bilayer

type, where BaTiO3 layer lies underneath of CuFe2O4 layer. CuFe2O4/BaTiO3 thin films

were annealed at temperature between 650℃ and 750℃, followed by either fast-cooling or

slow-cooling treatment. Ferroelectric and electrical properties were measured using

ferroelectric test system, digital multimeter, and impedance analyzer. Magnetic hysteresis (M-

H) behavior at room temperature was measured using vibration sample magnetometer (VSM)

with saturation magnetization (Ms) and coercivity (Hc) values of 280 emu/cm 3 and 225 Oe,

respectively. We have previously reported the multiferroic behavior of the similar structure,

i.e. Fe-BaTiO3 bi-layer thin films, in which the possibility of ferroelectric-ferromagnetic

coupling was suggested as a result of interfacial reaction between the layers. Top Fe layer,

however, is not chemically stable in an oxidizing atmosphere, and as a result CuFe2O4 spinel

film replaced Fe layer in this study.

Keywords : multiferroic, magnetoelectric, ferroelectricity, magnetic properties

P- 40


Poster session I

Electrical properties of (Bi0.9A0.1)(Fe0.975Cr0.025)O3 (A=Ho, Tb and Sm) thin

films prepared by chemical solution deposition

H. J. Kim, S. S. Kim 1 *, C. M. Raghavan, J. W. Kim, Y. J. Kim, J. -J. Oak, W. -J. Kim 1 ,

M. H. Kim 2 and T. K. Song 2 ,

1 Department of Physics, Changwon National University, Changwon, Gyeongnam 641-773,

Korea

2 School of Nano & Advanced Materials Engineering, Changwon National University,

Changwon, Gyeongnam 641-773, Korea

* E-mail address of the corresponding author : sskim@changwon.ac.kr

The small polarization as well as the high leakage current is the main issue for the

application of the BiFeO3 (BFO). In order to improve the polarization properties of the BFO

thin film, there were some research focused on Bi-site substitution with rare earth atom and

Fe-site substitution with Cr atom. Pure BFO and co-substituted (Bi0.9A0.1)(Fe0.975Cr0.025)O3 (A

= Ho, Tb and Sm) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a

chemical solution deposition method. The micro-structures of the thin films were

characterized by means of X-ray diffraction, Raman scattering spectra and scanning electron

microscope. The ferroelectric properties and the leakage current density of the pure BFO and

the co-substituted (Bi0.9A0.1)(Fe0.975Cr0.025)O3 (A = Ho, Tb and Sm) thin films were measured

using a ferroelectric tester and an electrometer.

P- 41


Poster session I

Analysis for crystal structure of rare-earth substituted BiFe0.975Zn0.025O3-δ

thin films and their electrical properties

J. W. Kim, S. S. Kim 1 *, H. J. Kim, C. M. Raghavan, Y. J. Kim, J. -J. Oak, W. -J. Kim 1 ,

M. H. Kim 2 and T. K. Song 2

1 Department of Physics, Changwon National University, Changwon, Gyeongnam 641-773,

Korea

2 School of Nano & Advanced Materials Engineering, Changwon National University,

Changwon, Gyeongnam 641-773, Korea

* E-mail address of the corresponding author : sskim@changwon.ac.kr

BiFeO3 (BFO) is the only single-phase multiferroic material so far be discovered, which

has transition temperatures (Curie temperature, Néel temperature) above room temperature.

Therefore, BFO has been widely studied in recent years because of potential applications at

room temperature. However, one of the major problems of BFO is high leakage current. The

low leakage current density in BFO thin films can be obtained by optimizing growth

condition, such as annealing atmosphere in chemical solution deposition. And the siteengineering

concept is also useful to reduce the leakage current in BFO thin films. Pure BFO

and co-doped (Bi0.9RE0.1)(Fe0.975Zn0.025)O3-δ (RE = Dy, Eu and La) thin films were prepared

on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. X-ray

diffraction analysis and Raman scattering spectrum reveal that all samples have a single-phase

rhombohedral perovskite structure. Surface morphology and film thickness were analyzed by

scanning electron microscope. The electrical properties of the thin films were investigated by

P-E hysteresis loops and leakage current conduction behavior measurements.

P- 42


Poster session I

Epitaxial growth of PbVO3 thin films with a large tetragonality factor

and their polarization reversal at nano-scale

R. H. Shin 1 , W. Jo 1,* , Y.-S. Seo 2 and J. S. Ahn 2

1

Department of Physics, Ewha Womans University, Seoul 120-750, Korea

2 Department of Physics, Pusan National University, Busan 609-735, Korea

* E-mail address of the corresponding author: wmjo@ewha.ac.kr

Polar magnetic PbVO3 (PVO) is one of the promising multiferroics because it has C-type

antiferromagetic ordering owing to dxy orbital and can be ferroelectric due to ABO3 structure

with a large tetragonality. Recently, a gigantic electrical polarization of 152 μC/cm 2 was

predicted in PVO by the Berry-phase calculation [1]. However, no one has observed yet the

polarization of PVO experimentally even down to 77 K. With a corner-shared pyramidal

structure of VO4, the short bond-length is one of the reasons to suppress their polarization [2].

The bonding length might be extended by controlling tetragonality in epitaxial thin films.

We elaborated to growth epitaxial PVO thin films by a pulsed laser deposition method using a

sintered PbVOx ceramic target. LaAlO3 (001) substrates were used because a-axis constant of

PVO is 3.79 Å, which is the same as that of LaAlO3. Control of oxygen partial pressure

during the deposition turns out to be crucial for the PbVO3 single-phase. Thus, we used a

mixed gas of argon and oxygen during deposition and in-situ annealing process, which is a

severely reducing condition against a normal synthesis of oxide materials. Laser fluence was

controlled in a range of 1.0 ~ 3.5 J/cm 2 . Crystallinity of the PVO thin films was investigated

by x-ray diffraction patterns. The films were epitaxially grown along c-axis normal to the

substrate with larger c lattice constant than bulk, which may due to compressive stress

between the film and the substrate. Local electrical polarization was studied using

electrostatic force microscopy in PVO thin films with different buffer layers. We will discuss

how to improve the structure of the PVO thin films and their electrical properties to show a

gigantic polarization that was predicted.

[Reference]

1. Y. Uratani, T. Shishidou, F. Ishii, and T. Oguchi, Jpn. J. Appl. Phys. 44, 7130 (2005).

2. A. Kumar, L. W. Martin, S. Denev, J. B. Kortright, Y. Suzuki, R. Ramesh, and V. Gopalan,

Phys. Rev. B, 75, 060101(R) (2007).

P- 43


Poster session I

The effects of Mn contents on electrical properties of BiFeO3

Dalhyun Do 1* , Myang Hwan Lee 1 , Tae Kwon Song 1 , Myong-Ho Kim 1 ,

Won Jeong Kim 2 , Yeon Soo Sung 3 and Sunggi Baik 3

1 School of Nano and Advanced Materials Engineering, Changwon National University,

Changwon 641-773, Korea

2 Department of Physics, Changwon National University, Changwon 641-773, Korea

3 Department of Materials Science and Engineering, Pohang University of Science and

Technology, Pohang 790-784, Korea

* E-mail address of the corresponding author: ddo@changwon.ac.kr

Multiferoic BiFeO3 (BFO) thin films exhibit coupled electric, magnetic, and structural

order parameters that result in simultaneous ferroic properties at room temperature. One of the

limitations for the use of BFO thin films in electronic devices such as new function memory

devices and spintronics is high leakage current that is mainly originated from the presence of

oxygen vacancies, Fe 2+ ions, impurity phases, etc. Thus it is necessary to control the leakage

current so that BFO thin films can be utilized for new function memory devices. In this study,

we deposited Mn-doped BFO thin films using a pulsed laser deposition method. The effects

of Mn contents on ferroelectric properties and leakage current were investigated.

P- 44


Poster session I

Spin waves measurement of room-temperature multiferroic BiFeO3

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 1,8*

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, UK

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

8 Center for Korean J-PARC Users, Seoul National University, Seoul 151-747, Korea

* E-mail address of the corresponding author : jgpark10@snu.ac.kr

Multiferroic materials are one of most challenging topics in the condensed matter

physics not only for its fundamental importance but also for huge future applications.

Although there are several systems that have multiferroic behavior, few compounds have both

magnetic and ferroelectric transition temperatures above room temperature. BiFeO3 is

probably the only exception with anti-ferromagnetic transition at TN=650 K and ferroelectric

transition at TC=1100 K.

In order to understand the microscopic magnetic interactions in BiFeO3, we have

carried out inelastic neutron scattering experiments on ten co-aligned single crystals using

AMATERAS beamline at J-PARC and MERLIN beamline at ISIS. In particular, we used a

so-called sample rotation method on MERLIN and could map out the full three-dimensional

magnon dispersion [1]. We also succeeded in measuring the full phonon dispersion curves.

For the analysis, we have calculated the magnon dispersion and conducted Monte-Carlo

simulation using Heisenberg Hamiltonian with two exchange parameters between the nearest

and the next nearest neighbors. A Dzyaloshinskii-Moriya-like term that possibly arises from

the spiral magnetic structure of BiFeO3 was also examined for both calculations. We could

determine, by carefully examining the AMATERAS and MERLIN data, the exchange

parameters that are consistent with both experimental results and the Monte-Carlo simulations.

We will also present our measured phonon dispersion curves.

1) Jaehong Jeong et al., Phys. Rev. Lett. 108, 077202 (2012)

P- 45


Poster session I

Real-space imaging of ferroelectric and structural antiphase domain walls

in Hexagonal YMnO3

K. Kobayashi 1 , K. Kurushima 2 , Y. Togawa 1 , Y. Horibe 3 , S-W. Cheong 3

and S. Mori 1,*

1 Osaka Prefecture University, Sakai, Osaka 599-8531 Japan

2 Toray Research Center, Ohtsu, Shiga 520-8567, Japan

3 Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA

* E-mail address of the corresponding author : mori@mtr.osakafu-u.ac.jp

Hexagonal manganites RMnO3 with R=Ho-Lu, Y and Sc exhibit have received much

attention because of their intriguing physical properties such as magnetoelectric effect [1]. In

the case of YMnO3, a structural phase transition from a paraelectric P63/mmc structure to a

non-centrosymmetric P63cm one takes place at about Tc~933K and a spontaneous

polarization (Ps) appears along the [001] direction in the ferroelectric (FE) phase [2]. Its FE

polarization was induced by a buckling of layered MnO5 polyhedra and displacements of Y

ions [3]. In addition, characteristic domain structures consisting of six FE and structural

antiphase domains appears in the FE phase, which can be identified as the “cloverleaf” pattern

[3-5]. Here, we have investigated characteristic FE and structural antiphase domain structures

in hexagonal RMnO3 (R=Y, Ho, Lu, and Yb) by the transmission electron microscopy (TEM).

In the FE phase of RMnO3 characteristic domain structures with the “cloverleaf” pattern is

found in the (110) plane, in addition to the (001) plane, and are inherent to the ferroelectric

phase of hexagonal RMnO3 [5]. In domain configuration with the cloverleaf pattern in the

(110) plane, the structural antiphase boundaries are inclined to be parallel to the [001]

direction [5]. In this study, we have applied high-angle annular-dark-field (HAADF) imaging

technique to hexagonal manganites [6] and mapped the atomic shifts of Y and Mn ions in the

FE phase of YMnO3, in order to elucidate the structural characteristics of the domain wall

structures. Two types of 180° domain walls can be identified. One is the transverse and

longitudinal domain walls with atomic displacements of a/3 and the other is the transverse

domain walls with atomic displacements of 2a/3. Note that a represents a unit lattice vector

along the direction. In contrast, the displacements related to the MnO5 polyhedral

remain intact across the domain walls. These features of the FE and structural antiphase

domain walls should be important to understand unusual physical properties in hexagonal

manganites.

[1] T. Katsufuji et al., Phys. Rev. B 66, 104419 (2001).

[2] T. Lonkai et al., Phys. Rev. B 69, 134108 (2001).

[3] T. Choi et al., Nat. Matter 9, 253 (2010).

[4] M. Lillenblum et al., J. Appl. Phys., 110, 052007 (2011).

[5] K. Kobayashi et al., (in press).

[6] Q. H. Zhang et al., Phys. Rev. B 85, 020102(R), (2012).

P- 46


Poster session I

Pressure-induced magnetic and ferroelectric phase transitions in

Multiferroic EuMn2O5

H. Kimura 1* , S. Fujiyama 1 , J. Lin 1 , M. Fukunaga 2 , Y. Noda 1 , H. Hiraka 3 , S.-A. Kim 4

and C.-H. Lee 1,4

1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University,

Sendai 980-8577, Japan

2 Department of Physics, Okayama University, Okayama 700-8530, Japan

3 Institute for Material Research, Tohoku University, Sendai 980-8577, Japan

4 HANARO, Korea Atomic Energy Research Institute Daejeon 305-600, Korea

* E-mail address of the corresponding author : kimura@tagen.tohoku.ac.jp

RMn2O5 (R = Y, Bi, rare-earth) is one of the prototypical multiferroic materials that

exhibit a rich variety of magnetoelectric effects. Since the successive magnetic and

ferroelectric phase transitions simultaneously take place, magnetic order has been thought to

be a primary order parameter for the ferroelectricity in this system. We recently have found

that in EuMn2O5, in which only Mn 3+ and Mn 4+ ions are responsible for the magnetism,

magnetic phase transition is induced by applying hydrostatic pressure. As temperature

decreases upon p > 0.6 GPa, shown in Figure, the magnetic propagation wave vector changes

from qM = (1/2, 0, 1/3) to (1/2, 0, 1/2), indicating that the period of magnetic unit cell as well

as the magnetic structure change at the phase transition. Quite interestingly, the ferroelectric

(FE1) – ferroelectric (FE2) phase transition concomitantly occurs at the magnetic phase

transition. To clarify the relevance between the ferroelectricity and the magnetic structure, we

carried out single crystal magnetic structure analysis of 153 EuMn2O5 using FONDER

diffractometer in JRR-3M and 4CD in HANARO under ambient- and high-pressure. In the

magnetic phase with qM = (1/2, 0, 1/3), cycloidal magnetic structure of manganese spins

propagating along c-axis is realized. On the

contrary in the magnetic phase with qM = (1/2, 0,

1/2), the spins arrange almost collinearly along

c-axis. The result indicates that the presence of

the cycloidal spin structure plays an important

role for inducing (or reducing) the electric

polarization in this compound. This work has

been supported by Grants-in-aid of Scientific

Research on Priority Areas (19052001), (A)

(21244051), and challenging Exploratory

Research (23654098).

Figure: Magnetic and dielectric phase diagram

as functions of temperature and hydrostatic

pressure for EuMn2O5.

P- 47


Poster session I

Preparation of epitaxial BiFeO3 thin films by RF planar magnetron

sputtering

Yusuke Takada*, Shota Seto, Seiji Nakashima, Hironori Fujisawa,

Masafumi Kobune and Masaru Shimizu

Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-

2201, Japan

* E-mail address of the corresponding author : er11n018@steng.u-hyogo.ac.jp

BiFeO3(BFO) is a multiferroic material which simultaneously shows ferroelectricity and

antiferromagnetism. It has also been expected as one of lead-free ferroelectrics because of its

large remanent polarization (Pr ~100 �C/cm 2 ) in a thin film form. BFO thin films have

generally been prepared by pulsed laser deposition (PLD) and chemical solution deposition

(CSD). However, it is well-known that growth of high quality BFO thin films by planar

sputtering is difficult. It has been already reported that leakage current of BFO thin films can

be reduced by controlling domain structure for reducing conductive 109 o domain walls. 1) In

this study, we employed RF planar magnetron sputtering for BFO thin film growth and

demonstrated growth of high quality BFO thin film by controlling domain structure using offcut

substrates.

300-nm-thick BFO thin films were epitaxially

grown on SrRuO3(SRO)(50 nm)/SrTiO3(STO)(001)

with 4 ○ off-cut along [110] direction by RF planar

magnetron sputtering. Substrate temperature, sputtering

pressure, Ar/O2 gas flow rate and deposition rate were

fixed at 610 ○ C, 0.5 Pa, 4/2 sccm and 1.1 nm/min,

respectively. Bi2O3 + �-Fe2O3 mixed and calcined

powder with Bi/Fe ratio of 1.4 was used as a target

because of high volatility of Bi2O3.

The BFO thin film with Bi/Fe ratio of 1.0 shows a

smooth surface with step and terrace structure as shown

in Fig.1. PFM revealed that it has single domain

structure. Figure 2 shows ferroelectric D-E hysteresis

loops at RT. and frequency of 20 kHz. Remanent

polarization (2Pr) and coercive filed (2Ec) were 120

�C/cm 2 and 252 kV/cm, respectively. The 2Pr value

shows good agreement with that of bulk single crystal. 2)

By controlling Bi/Fe ratio and domain structure, the

high quality BFO thin film was obtained by RF planer

magnetron sputtering.

1) H. W. Jang et al., Adv. Mater., 21, 817 (2009).

2) D. Lebeugle et al., Appl. Phys. Lett., 91, 022907

(2007).

P- 48

Fig.1. An AFM image of the BFO

thin film.

Fig.2. D-E hysteresis loops of the

BFO thin film.


Poster Session II

10:30 ~ 12:00, August 9

Gallery, 2F, International Building


Poster session II

Fabrication of PZT/ZnO core-shell nanorods with different PZT

thicknesses by MOCVD

Chiaki Kobayashi*, Hironori Fujisawa, Seiji Nakashima and Masaru Shimizu

Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo,

671-2201, JAPAN

* E-mail address of the corresponding author : er12n024@steng.u-hyogo.ac.jp

We have demonstrated preparation and characterization of PZT/ZnO core-shell nanorods

using ZnO nanorods as a positive template by metalorganic chemical vapor deposition

(MOCVD). In MOCVD, since ZnO nanorods are grown by self-assembly, it is difficult to

control the size, the density (the number of nanorods per unit area), and the arrangement of

nanorods. In this study, ZnO nanorods were prepared by 2-step growth method, and PZT/ZnO

core-shell nanorods with different PZT thicknesses were fabricated.

ZnO nanorods were grown in the vapor-solid (V-S) growth mode on a-sapphire substrate

by MOCVD using Zn(C2H5)2 and O2 as source materials. In the V-S growth mode, the density

of ZnO nanorods is determined by the diameter

because they were close-packed on the substrate.

Therefore, it was difficult to change the density

independently of the diameter although the diameter

can be controlled by the growth temperature.

In the 2-step growth method, ZnO nanorods with

a large diameter were deposited on a-sapphire, and

subsequently ZnO nanorods with a smaller diameter

were deposited on the preceeding nanorods, as shown Fig.1 FE-SEM photograph of ZnO

in Fig.1. Therefore, the density of ZnO nanorods, 2.3 nanorods grown by 2-step growth

method

�m

Fig.2 FE-SEM photograph of

PZT/ZnO core-shell nanorods with

PZT thickness of 180 nm.

-2 , was determined only by the diameter of the

firstly grown nanorods, and reduced much less than

that calculated from the diameter of subsequently

grown ZnO nanorods, 240.6 �m -2 . By using the ZnO

nanorods with a density as low as 2.3 �m -2 , PZT/ZnO

core-shell nanorods with PZT thicknesses from 20 to

180 nm were successfully fabricated, as shown in

Fig.2. At the conference, piezo- and ferro-electric

properties of the PZT/ZnO core-shell nanorods with

different diameters will be also discussed.

P- 49


Poster session II

Local charge conductions in multiferroic BiFeO3 nanostructures

Taekjib Choi 1* , Sahwan Hong 2 , Jihoon Jeon 2 , Yunseok Kim 3 , Hosang Lee 1 ,

Ho-Young Joo 1 , Jinsik Choi 2 , Jin-Soo Kim 2 , Sergei V. Kalinin 3 and Baeho Park 1

1 Hybrid Materials Research Center and Institute of Nanotechnology and Advanced Materials

Engineering, Sejong University, Seoul 143-747, Korea

2 Division of Quantum Phases & Devices, Department of Physics, Konkuk University, Seoul

143-701, Korea

3 The Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge,

TN 37831, USA

* E-mail address of the corresponding author : tjchoi@sejong.ac.kr

Semiconductor multiferroic thin films and nanostructures have emerged as functional

elements in oxide electronics. They consist of domain structures with switchable electric

spontaneous polarization by applying external bias. Recently, remarkable charge conductions

at ferroelectric domain/walls have been revealed in various ferroelectrics, demonstrating

intriguing interplay between electronic transport properties and ferroelectric polarization. In

this work, we report local charge conductions in BiFeO3 nanostructure coupling with local

electric polarization will be presented. We have fabricated highly ordered BiFeO3 nanoislands

using anodic aluminium oxide templates by pulsed-laser-deposition. Their local

charge conductivity and domain structures were studied using piezoresponse force

microscopy and conductive atomic force microscopy. BiFeO3 nano-islands showed a strong

flexoelectric effect for charge conductions and electric polarization with a different electrode

or substrate. Our results should provide a fundamental understanding of local charge

conduction with domain structures in ferroelectric nanostructures.

P- 50


Poster session II

Intaglio Nanotemplates Based on Atomic Force Microscopy for

Ferroelectric Nanodots

Jong Yeog Son 1 and Young-Han Shin 2*

1 Department of Applied Physics, College of Applied Science, Kyung Hee University, Suwon

446-701, Korea,

2 Departments of Physics, Chemistry and EHSRC, University of Ulsan, Ulsan 680-749,

Korea

* E-mail address of the corresponding author : hoponpop@ulsan.ac.kr

We demonstrate the nano-intaglio process to form a nanotemplate and a series of

nanoscale grooves using atomic force microscopy. Nanopores are hoed with a diameter of

20 nm on the surface of a SrTiO3 thin film epitaxially grown on an Nb-doped SrTiO3

substrate using a diamond tip. For the demonstration of the nano-intaglio process, a

nanotrench is intaglioed at a length of approximately 150 nm and a width of approximately 20

nm. The nano-intaglio process enables the fabrication of a nanotemplate with a highest

packed hexagonal array, with a density of approximately 6.0×10 11 /inch 2 . A ferroelectric

poly(vinyliden fluoride-ran-trifluoroethylene: PVDF-TrFE) nanodot with a diameter of about

20 nm is formed by filling a nanopore with a PVDF-TrFE solution, whose ferroelectric

properties are confirmed using piezoelectric force microscopy.

P- 51


Poster session II

Terahertz time-domain spectroscopy study of LiNbO3

Hikaru Igawa 1* , Tatsuya Mori 1 , Kei Iwamoto 2 , Naoki Toyota 2 and Seiji Kojima 1

1 Graduate School of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki

305-8573, Japan

2 Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578,

Japan

* E-mail address of the corresponding author : s1220414@u.tsukuba.ac.jp

Temperature and frequency dependence of the dielectric properties of LiNbO3 crystals

have been studied by THz time-domain spectroscopy (THz-TDS) with the use of a standard

transmission configuration, covering the frequency range of 0.1 to 2.0 THz and temperature

range of 5 to 300 K. LiNbO3 is an uniaxial electro-optic crystal, and Curie temperature (TC) is

1463 K [1] . The measured sample was x-cut crystal, and thickness was 400 μm. The x-cut

plane has the ordinary and extraordinary axis. Figure 1 shows experimental results of the

complex dielectric constants at room temperature and fitting results of Lorentzian curves.

Filled squares are along ordinary axis, circles are along extraordinary axis, and solid lines are

fitting results. The obtained fitting parameters are following. The resonance frequency,

resonance width, oscillator strength, and static dielectric constant of the ordinary axis are 4.24

THz, 0.58 THz, 28.1, and 44.4 respectively. Those of the extraordinary axis are 3.82 THz,

0.76 THz, 5.53, and 26.2 respectively. These results are in good agreement with the previous

report [2] .

�'

60

50

40

30

(a)

LiNbO 3

Ordinary

Extraordinary

20

0.0 0.5 1.0 1.5 2.0 2.5

Frequnecy (THz) Frequency (THz)

Fig. 1. (a) Real and (b) imaginary part of the dielectric constants of LiNbO3 at room

References

1. A. S. Barker, JR., and R. Loudon, Phys. Rev. 158, 2 (1967).

2. M. Schall, H. Helm, and S. R. Keiding, Int. J. Infrared and Millimeter Waves 20, 4 (1999).

�''

P- 52

4

2

0

(b)

0.0 0.5 1.0 1.5 2.0 2.5


Poster session II

Coherent Entropy-Wave Generation in Quantum Paraelectrics

Akitoshi Koreeda 1,2* , Masaki Takesada 3 and Toshirou Yagi 3

1 Department of Physics, Tohoku University, Sendai 980-8578, Japan

2 Japan Science and Technology Agency, PRESTO, Kawaguchi 332-0012, Japan

3 Department of Physics, Hokkaido University, Sapporo 060-0810, Japan

* E-mail address of the corresponding author : kore@m.tains.tohoku.ac.jp

We have recently reported that “wave of entropy or temperature”, which is also known

as “second sound”, can exist in SrTiO3 and KTaO3 at cryogenic temperatures [1-3]. In this

paper, we report on active generation of “coherent entropy-wave” in these systems by using

laser-induced thermal grating technique. Figure 1 shows the measurement principle and the

experimental results of impulsive stimulated thermal scattering (ISTS) on KTaO3. On cooling

from 30K, the decay rate becomes faster according to the temperature dependence of the

thermal diffusivity. However, there are a few anomalous aspects (i) the rising rate appears to

become slower and the profile becomes “rounder” on cooling; (ii) the decay rate does not

become faster than it is predicted from the known thermal diffusivity. In Fig.1, we also show

the fitted “heat-wave functions” (i.e., not an exponential function). The fitted response

reproduces the observed signal quite well, implying that we are about to generate the coherent

wave of heat.

Figure 1. Measuring principle of ISTS (left), and temperature dependence of the observed

and fitted responses (right). The fitted function is the damped oscillator function for heat.

References:

1. A. Koreeda, R. Takano, and S. Saikan, Phys. Rev. Lett., 99, 265502 (2007)

2. A. Koreeda, R. Takano, and S. Saikan, Phys. Rev. B 80, 165104 (2009)

3. A. Koreeda, R. Takano, A. Ushio, and S. Saikan, Phys. Rev. B 82, 125103 (2010)

P- 53


Poster session II

Brillouin scattering study of liquid-glass transitions in ternary mixture of

water, trehalose and ionic liquid

Haruki Takayama * , Tomohiko Shibata, Takahiro Ishii and Seiji Kojima

PAS, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

* E-mail address of the corresponding author : s1220450@u.tsukuba.ac.jp

The ternary mixtures of water, sugar, ionic liquid have attracted attention as the new

candidate of bioprotectants. To clarify the physical properties of supercooled liquid and

glassy states at low temperatures, the liquid-glass transitions of ternary mixtures of water,

trehalose and 1-butyl-3-methylimidazolium chloride were studied by Brillouin scattering. The

refractive index was measured accurately as the function of content and temperature to

determine elastic properties from Brillouin frequency shift and peak width. The relaxation

times of structural relaxation related to a liquid-glass transition were determined as a function

of temperature. It is found that Meyer-Neldel rule holds for the activation energy and

prefactor of the Arrhenius law of relaxation time [1].

Sound velocity (m/s)

4000

3500

3000

2500

2000

1500

1000

500

0

[bmim]Cl 10 wt% trehalose 50 wt%

[bmim]Cl 50 wt% trehalose 10 wt%

-200 -150 -100 -50 0 50 100

Temperature (�C)

P- 54

2x10 7

1x10 7

0

Attenuation (m -1 )

Fig. 1 Temperature dependences of sound velocity and attenuation of ternary mixtures of

water, trehalose and 1-butyl-3-methylimidazolium chloride.

Reference

1. Daniele Ielmini, Mattia Boniardi, Appl. Phys. Lett. 94, (2009) 091906.


Poster session II

Structural and dielectric investigation

of the charge ordered organic compound α’-(BEDT-TTF)2IBr2

A. Yamashita 1 , C. Hyon 1 , M. Watanabe 2 , M. Fukunaga 1,3 , K. Kobayashi 4 , R. Kumai 4 ,

K. Yamamoto 5 , K. Yakushi 5 and Y. Noda 1*

1 IMRAM, Tohoku University, Sendai 980-8577, Japan

2 NICHe, Tohoku University, Sendai 980-8579, Japan

3 Grad. Sch. of Natural Sci. and Tech., Okayama University, Tsushimanaka 700-8530, Japan

4 CMRC, the High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan

5 IMS, National Institutes of Natural Sciences, Okazaki 444-8585, Japan

* E-mail address of the corresponding author : ynoda@tagen.tohoku.ac.jp

In the conventional ferroelectric materials such like displacement type or order-disorder

type ferroelectrics, electric dipole moments are essentially relating to the atomic displacement

breaking the inversion symmetry. However, another possibility of ferroelectric category

named “electronic-ferroelectric” has been discussed among physicists in the recent years. In

electronic-ferroelectrics, ordering of electron charges in the conducting layer forms

spontaneous polarization, while the atomic/molecular positions still hold inversion symmetry.

Unfortunately, no electronic-ferroelectric material with reversible spontaneous

polarization was found up to now. However several charge ordering materials were reported

as candidate for electronic-ferroelectrics [1-4]. The semi-conductive organic charge transfer

salt α’-(BEDT-TTF)2IBr2 is one of such clue. This salt exhibits three sequential phase

transitions as follows; the first one is from the room temperature phase (Phase-I: SG P-1) to

the higher resistive phase (Phase-II) considered as charge ordered state at 204 K, the second

one is from Phase-II to Phase-III with larger SHG signal at 160 K, and the third one is from

Phase-III to the nonmagnetic Phase-IV at 25 K [4]. Phase-III is considered as a clue to

electronic-ferroelectric. In this study, low temperature Xray

diffraction experiments were conducted to investigate

the nature of each phase at BL-8A/KEK-PF. Furthermore

dielectric measurements by the Double-Wave method were

carried out. In Phase-II and IV, 2-fold superlattice was

found, and the spatial patterns of charge ordering in Phase-

II and phase-III (Fig. 1) were revealed. The other details of

the results will be discussed.

[1] N. Ikeda et al., Nature 436(2005)1136.

[2] K. Yamamoto et al., J. Phys. Soc. Jpn. 77(2008) 074709

[3] M. Naka et al., J. Phys. Soc. Jpn. 79(2010) 063707

[4] Y. Yue et al., J. Phys. Soc. Jpn., 78(2009) 004.

P- 55

Fig.1. Charge ordering

pattern and conjectured

dipole moment in Phase-III


Poster session II

Orbital Order in YTiO3 Observed by Super Accurate Synchrotron X-ray

Diffraction

Terutoshi Sakakura 1* , Yoshihisa Ishikawa 1,2 , Takahiro Nakano 1 , Hiroyuki Kimura 1 ,

Yukio Noda 1 , Yoshinori Tokura 3 and Shigeki Miyasaka 4

1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1

Katahira, Aoba, Sendai 980-8577, Japan.

2 High Energy Accelerator Research Organization, KEK Tokai Campus, 203-1 Shirakata,

Tokai, Naka, Ibaraki 319-1106, Japan.

3 Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo,

Tokyo 113-8656 Japan.

4 Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan

* E-mail address of the corresponding author : sakakura@tagen.tohoku.ac.jp

Orbital state is the fundamental information of a crystal structure and a chemical bond

strongly relating to phase transition phenomena. Whereas orbital ordering in materials have

been mainly studied via methods observing magnetic momentum distribution in real space

such as polarized neutron diffraction technique, X-ray structure analysis, which observes

ligand atoms simultaneously, has an advantage to investigate the mechanism. We applied

super accurate X-ray diffraction using synchrotron radiation to orbital order phase of YTiO3

at room temperature. Here, the meaning of super accurate is that the observed Bragg

reflection intensities are almost free from multiple scattering contaminations. The experiment

was carried out using four-circle diffractometer at beam line 14A at Photon Factory, Tsukuba,

Japan and all integrated intensities were measured avoiding the errors caused by multiple

scattering. We clearly observed quadrupoles of ordered Ti-3d orbitals (3d 1 ) as shown in Fig. 1.

Four density maxima of the quadrupoles are all attracted towards the closest four Y 3+ ions and

the linear combination coefficients observed are consistent with other methods and theoretical

calculations. This work has been supported by Grants-in-aid of Scientific Research on (A)

(21244051), and challenging Exploratory Research (23654098).

P- 56

Fig.1: (a) Crystal structure around

TiO6 octahedron and (b) deformed

electron density map (Fourier

transformation of Fobs – Fcalc

after refinement using neutral

atoms). Four density maxima near

Ti atom corresponding to Ti-3d

ordered orbital locate towards the

closest four Y 3+ ions.


Poster session II

Large strain response in Nb-modified BNKT-ST lead-free piezoelectric

ceramics

Rizwan Ahmed Malik 1 , Hyoung-Su Han 1 , Hyun-Young Lee 1 , Ali Hussain 2 ,

Van-Quyet Nguyen 1 , Chang-Ho Yoon 1 and Jae-Shin Lee 1,*

1 School of Materials science and Engineering, University of Ulsan, Ulsan 680-749, Korea

2 School of Nano and Advanced Materials Engineering, Changwon National University,

Gyeongnam 641- 773, Korea

* E-mail address of the corresponding author: jslee@ulsan.ac.kr

Lead-free 0.96Bi1/2(Na0.84K0.16)1/2(Ti1-xNbx) O3–0.04SrTiO3 (BNKTN-ST, with x = 0.00,

0.005, 0.010, 0.015, 0.020, 0.025 and 0.030) ceramics were synthesized by conventional solid

state reaction method. The effect of Nb substitution on crystal structure, dielectric,

ferroelectric and electric field-induced strain behavior of BNKTN-ST was investigated in

detail. XRD patterns revealed the formation of pure perovskite phase with a structural

transition from the coexistence of rhombohedral and tetragonal to a pseudocubic phase at x =

0.020. The temperature-dependent dielectric peaks of the BNKTN-ST ceramics broadened

and ferroelectric polarizations decreased with increasing Nb concentration. Ferroelectric and

bipolar field induced-strain curves indicated a significant disruption of ferroelectric order

upon Nb addition into BNKT-ST ceramics. This destabilization of the ferroelectric order was

accompanied by an enhanced field-induced strain. A giant field-induced strain (S = 0.45%)

with a normalized strain (d * 33 = Smax/Emax = 900 pm/V) was observed at 50 kV/cm at x = 0.02.

These results show that Nb-modified BNKT-ST system can deliver much higher fieldinduced

strain at relatively low applied electric field as compared to existing lead-free Biperovskite

ceramics.

P- 57


Poster session II

Enhanced piezoelectric properties of lead-free (Bi0.5Na0.5)TiO3-BaTiO3 thin

films by pulsed laser deposition

Jin Su Park 1 , Myang Hwan Lee 1 , Da Jeong Kim 1 , Dalhyun Do 1 , Myong Ho Kim 1 ,

Sang Su Kim 2 , Won Jeong Kim 2 , Sang Wook Kim 2 , Hae In Choi 2

and Tae Kwon Song 1 *

1 School of Nano & Advanced Materials Engineering, Changwon National University,

Gyeongnam 641-773, Korea

2 Department of Physics, Changwon National University, Gyeongnam 641-773, Korea

* E-mail address of the corresponding author : tksong@changwon.ac.kr

The (Bi0.5Na0.5)TiO3-BaTiO3 based materials have been developed as a promising leadfree

piezoelectric material for environmentally benign good piezoelectric devices. In this

work, the 0.935(Bi0.5Na0.5)TiO3-0.065BaTiO3 (BNBT) thin films have been grown on

Pt(111)/Ti/SiO2/Si substrates by a using pulsed laser deposition method. Deposition

conditions were changed with oxygen pressure 100, 200, and 300 mTorr and repetition

frequency at 3 Hz and 5 Hz respectively, at deposition temperature of 750 o C. Structural and

electrical properties of the films were investigated by x- ray diffractometer and electrical

measurement system. The BNBT thin film exhibited the remnant polarization (2Pr) of 14

�C/cm 2 deposited at 3 Hz and 300 mTorr. The piezoelectric responses of the thin films were

investigated using piezoelectric force microscopy with a lock in amplifier. The thin films

exhibited piezoelectric properties of d33 value of 150 pm/V.

P- 58


Poster session II

Na excess effects on dielectric and piezoelectric properties of lead free

(Na0.53+xK0.47)(Nb0.55Ta0.45)O3 ceramics.

S. Y. Lim 1 , G. H. Ryu 1 , A. Hussain 1 , D. Do 1 , T. K. Song 1 , M. H. Kim 1,* and W. J. Kim 2

1 School of Nano & Advanced Materials Engineering, Changwon National University,

Gyeongnam 641-773, Korea

2 Department of Physics, Changwon National University, Gyeongnam 641-773, Korea

* E-mail address of the corresponding author : mhkim@changwon.ac.kr

Lead-based ceramics are widely used for piezoelectric and ferroelectric applications.

However, lead oxide present in these materials not only pollutes the environment but also

harms human health. Therefore lead-free ceramics are urgently required replace theses toxic

lead-based materials. In this regard (Na0.5K0.5)NbO3 based ceramics are considered most

promising candidate materials for lead-free piezoelectric and ferroelectric applications. In this

work, we have investigated the effect of Na excess on the dielectric piezoelectric properties of

(Na0.53+xK0.47)(Nb0.55Ta0.45)O3 (NKNT) ceramics. A high piezoelectric coefficient d33= 330

pC/N was obtained at x= 0.015. These results show that NKNT ceramics are highly promising

material for lead-free piezoelectric applications.

P- 59


Poster session II

Effect of the Porosity on Templated Grain Growth Behavior in (K,Na)NbO3

Ceramics

J. H. Choi 1 , K.W. Chae 2 , J.S. Kim 1 and C.I. Cheon 1,2*

1

Department of Semiconductor & Display Engineering, Hoseo University

2

Department of Materials Science and Engineering, Hoseo University, Baebang, Asan,

Chungnam, Korea

* E-mail address of the corresponding author : cicheon@hoseo.edu

Recently, lead-free piezoelectric ceramics have been researched for replacing

Pb(Zr,Ti)O3 (PZT)-based ceramics due to environmental restrictions. (K,Na)NbO3 (KNN)based

piezoelectric ceramics show the best piezoelectric properties among several lead-free

piezoelectric compositions like (Bi,Na)TiO3, Bi-layered structure ferroelectrics, etc. The

KNN ceramic is, however, thought to replace Pb-based piezoelectric ceramics in limited

application fields due to its inferior piezoelectric properties to the Pb-based one.

Textured ceramics prepared by template grain growth (TGG) have been known to show

superior piezoelectric properties to the conventional polycrystalline ceramics. In KNN

ceramics, the TGG has been occurred only with the sample with sintered density higher than

92% because the pore-drag force suppresses the grain boundary migration in porous samples.

The porosity seems to be one of the important factors for templated grain growth of KNNbased

ceramics. However, it was confirmed that the formation of the liquid phase was

necessary for the TGG in other piezoelectric ceramics.

The purpose of this study is to understand the effect of the porosity on the TGG behavior

in KNN ceramics with or without the dopant (CuO) which forms liquid phase during sintering.

NaNbO3 templates, (K, Na) NbO3 powder, and CuO were mixed by ball milling. NaNbO3

seed crystals were prepared by molten salt method. The slurry was tape-casted, laminated, cut,

and burned out the binder. The green density of the sample was enhanced by cold-isostatic

pressing (CIP) after binder burn-out. The pressure was controlled from 0 to 150MPa during

CIP in order to prepare the samples with various green densities. The samples were sintered at

1100 ~ 1175 ℃ for 4 hours. The sintered density, microstructure, and the degree of texturing

were investigated. The dielectric and piezoelectric properties were also analyzed. The TGG

behaviors for KNN ceramics with various densities were compared. The effect of the porosity

on the TGG behavior and piezoelectric properties in textured KNN ceramics will be presented.

P- 60


Poster session II

Low-frequency Impedance Spectroscopy of BiAlO3 modified

Bi0.5(Na0.75K0.25)0.5TiO3 lead-free piezoelectric ceramics

Amir Ullah, Aman Ullah, Chang Won Ahn, Bong Chan Park and Ill Won Kim *

Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan,

Ulsan 680-749, Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

We have synthesized lead-free piezoelectric ceramics (1-x)Bi0.5 (Na0.75K0.25)0.5TiO3-

xBiAlO3 (BNKT-BA, 0 ≤ x ≤ 0.10) by a solid state reaction method. The effect of varying BA

concentration on various properties of BNKT ceramics has been investigated. X-ray

diffraction (XRD) revealed a pure perovskite phase for composition x ≤ 0.050. The real part

of dielectric constant was investigated over a wide range of temperature (0 ~ 500 o C) and

frequency (0.01 ~ 100 KHz). The depolarization temperature (Td) and maximum temperature

(Tm) were found around 120 o C and 294 o C, respectively. Dielectric studies revealed that the

compound has diffused nature and that relaxor behavior occurs at a temperature around (Td).

Analyzing the complex impedance relaxation through a Cole-Cole plot, we found the

frequency dependence relaxation behavior in the material. The thermal activation energy for

conduction process was calculated from the slopes of ac conductivity at 1Hz and were found

1.22, 0.840, 1.014, 0.899eV for x = 0, 0.050, 0.075 and 0.100, respectively. The magnitude

of Z΄ (real impedance) is observed to decrease with increasing temperature and frequency.

P- 61


Poster session II

Ferroelectric and Piezoelectric Properties of Polycrystalline PbTiO3 Film

with Nanograin

Jong-Pil Lee 1 , Soo Whan Lee 2 , Jeong Keun Lee 2 , Yun-Soo Lim 1 , Jungho Ryu 3 ,

Dong-Soo Park 3 and Dae-Yong Jeong 2*

1 Department of Materials Sci. & Eng., Myongji University, Gyeonggi 449-728, Korea

2 School of Materials Sci. & Eng., Inha University, Incheon 402-751, Korea

3 Functional Ceramics Research Group, KIMS, Gyeongnam 641-831, Korea

* E-mail address of the corresponding author : dyjeong@inha.ac.kr

PbTiO3 is a typical ferroelectric material of tetragonal crystal structure with large c/a

ratio. Due to large c/a ratio, pure polycrystalline film or bulk has not been fabricated and

consequently ferroelectric and piezoelectric properties were not reported. Instead PbTiO3 was

grown epitaxially on such a SrTiO3 single crystal substrate. It is known that nano-grain

ferroelectric materials show the different behavior from macro grain materials. In this

presentation, we fabricated the polycrystalline PbTiO3 film with nano grain and high density.

XRD revealed that crystal structure was distorted and c/a was dramatically reduced. PbTiO3

film showed clear ferroelectric behavior and larger dielectric constant that reported before. In

addition, PbTiO3 film showed ~ 50 o C higher phase transition temperature.

P- 62


Poster session II

Piezoelectric Enhancement of Relaxor-based Lead-free Piezoelectric

Ceramics by Nanodomain Engineering

Ichiro Fujii 1 , Ryuta Mitsui 1 , Kouichi Nakashima 1 , Nobuhiro Kumada 1

and Satoshi Wada 1*

1 Material Science and Technology, Interdisciplinary Graduate School of Medical and

Engineering, University of Yamanashi, 4-4-37 takeda, Kofu, Yamanashi 400-8510, Japan

* E-mail address of the corresponding author : swada@yamanashi.ac.jp

It is well known that Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) and Pb(Mg1/3Nb2/3)O3 -PbTiO3

(PMN-PT) crystals exhibit high piezoelectric performances owing to their engineered domain

configuration. Recently, it was reported that piezoelectric constant d33 of the PZT single

crystals was around 1,400 pC/N by Ye et. al., and lower than those of PZN-PT and PMN-PT

single crystals. These results suggested that domain engineering might be the best way to

enhance the piezoelectricity, and relaxor-based ferroelectrics could be suitable for the domain

engineering. This is because that for normal ferroelectrics such as BaTiO3 (BT) and KNbO3

(KN), to control domain configuration and domain wall density, the microstructure of

ceramics must be controlled such as grain size, density, orientation and etc. On the other

hand, for the relaxor-based ferroelectrics, the domain configuration was dependent on

chemical composition and orientation. This means that if relaxor-based lead-free

ferroelectrics are prepared, it can be expected that they might have high piezoelectric

performances. Recently, we reported that BT-Bi(Mg1/2Ti1/2)O3 (BT-BMT) was relaxor

ferroelectrics with high Tmax over 250 ˚C. Thus, it is possible to control domain

configurations by solid solution system between the above relaxors and normal ferroelectric

such as BiFeO3 (BF) with high Tc of 830 ˚C. In this study, the BT-BMT-BF system

ceramics were prepared using a conventional solid–state reaction and their crystal structure

and electrical properties were investigated. A single phase of perovskite was prepared for

these ceramics with various compositions. TEM observation revealed that BT-BMT had no

domain configuration while BF-rich ceramics had normal rhombohedral domain

configurations. Moreover, the ceramic with the intermediate composition between relaxor

and BF had nanodomain configuration with domain sizes less than 50 nm. For the ceramics,

the temperature dependences of dielectric constants were measured at various frequencies,

and the Tmax was determined. As the results, the Tmax increased with increasing BF content,

while Tmax decreased with increasing BT content. Finally, their strain vs. electric-field

behaviors were measured, and the relaxors showed typical electrostrictive behavior while BFrich

ceramics showed typical butterfly-like ferroelectric strain behavior. For the ceramics

with nanodomain configuration, the strain curve with hysteresis-less and high slope was

clearly observed and the apparent d33* (Smax/Emax) from the slope was over 850 pC/N.

P- 63


Poster session II

Piezoelectric Properties of Ternary Pb(Mn1/3Nb2/3)O3-PbTiO3-PbZrO3

System Solid Solutions

Haruka Okuda * , Masafumi Kobune and Hiroshi Nishioka

Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji,

Hyogo 671-2201, Japan

* E-mail address of the corresponding author: et12b016@steng.u-hyogo.ac.jp

Recently, high power piezoelectric materials are required to apply for ultrasonic

vibrators and piezoelectric transformers. For these applications, a piezoelectric materials

which have low mechanical fatigue under large amplitude drive and high conversion

efficiency from mechanical energy to electrical energy is needed. The ceramics for high

power piezoelectric materials should have a high piezoelectric constant d, a high mechanical

quality factor Qm, and a large electromechanical coupling factor k. In the present study, to

develop the piezoelectric material with excellent piezoelectric parameters described above,

piezoelectric properties of ternary Pb(Mn1/3Nb2/3)O3-PbTiO3-PbZrO3 (PMnN-PT-PZ) system

solid solutions were investigated in details.

Reagent-grade PbO, TiO2, ZrO2, MnCO3・0.46H2O and Nb2O5 were used as starting

materials. PMnN-PT-PZ powder was fabricated by a two-step solid-state reaction using a

columbite precursor. The powder was pressed into discs and sintered at 1220 o C for 3 h in air.

The crystalline phase was analyzed, and di-, piezo- and ferroelectric properties were measured.

The crystal structure changed from tetragonal to

rhombohedral phases in the vicinity of morphotropic

phase boundary (MPB) composition with increasing

PMnN. The MPB compositions were almost presumed

to be PMnN/PT/PZ = 1.5-14/43-52/43-46.5, based on

the XRD results. d33, kp and Qm showed maxima (156

pC/N, 34% and 890) at PMnN/PT/PZ = 11/44/45,

respectively. In contrast, Qm showed a tendency to

increase gradually with increasing PMnN content.

Thus, 0.11PMnN-0.44PT-0.45PZ ceramics shows

great promise for piezoelectric actuator applications

because of its excellent piezoelectric properties such as

d33 = 157 pC/N, d31 = 51 pC/N, Qm = 695, kp = 34%,

k31 = 20%, ��33 T /��0 = 622, tan δ = 0.52% and Tc =

353 o C.

P- 64

Fig. 1. Variations in (a) d33 and (b)

Qm at room temperature of ternary

PMnN-PT-PZ (PMnN/PT/PZ = 4-

14/42-52/44-54) ceramics.


Poster session II

Acoustic anomalies and central peaks in 0.83Pb(Mg1/3Nb2/3)O3–0.17PbTiO3

single crystal studied by the micro-Brillouin scattering

Tae Hyun Kim 1,2* , Jae-Hyeon Ko 2 and Seiji Kojima 1

1 PAS, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

2 Department of Physics, Hallym University, Chuncheon, Gangwondo 200-702, Korea

* E-mail address of the corresponding author : s1130117@u.tsukuba.ac.jp

Dynamic properties of relaxor ferroelectric 0.83Pb(Mg1/3Nb2/3)O3–0.17PbTiO3 (PMN-

17PT) single crystals have been studied by miro-Brillouin scattering in a wide temperature

range between 90 and 860 K on both cooling and heating. The Brillouin spectra were

measured by using a tandem Fabry-Perot interferometer combined with an optical microscope.

The temperature dependence of Brillouin shift showed the deviation from normal lattice

anharmonicity below the Burns temperature ~ 733 K upon cooling. The observed acoustic

behaviors combined with the central peak dynamics clearly indicated the existence of

dynamic polar nanoregions (PNRs) in PMN-17PT. This study revealed that longitudinal

acoustic (LA) mode frequency showed a diffuse elastic anomaly upon cooling near the cubicrhombohedral

phase transition temperature (Tc) as well as thermal hysteresis around Tc,

which indicates a typical nature of a first order phase transition.

*This research was supported in part by the Marubun Research Promotion Foundation

and Basic Science Research Program through the National Research Foundation of

Korea(NRF) funded by the Ministry of Education, Science and Technology (2010-0010497).

Frequency shift (GHz)

47

46

45

44

43

42

100 200 300 400 500 600 700 800

Temperature (K)

Cooling

Heating

P- 65

FWHM (GHz)

3

2

1

100 200 300 400 500 600 700 800

Temperature (K)

Cooling

Heating

Fig. 1. The temperature dependences of the Brillouin frequency shift and the FWHM of the LA

mode on both cooling and heating processes.

References

1. S. Kojima and J. -H. Ko, Curr. Appl. Phys. 11 (2011) 522.

2. J. –H. Ko et al., Phys. Rev. B 82 (2010) 104110.


Poster session II

Influence of tantalum substitution on dielectric, ferroelectric and fieldinduced

strain behavior of lead-free 0.99[Bi0.5(Na0.82K0.18)0.5Ti1-xTax)O3]-

0.01LiSbO3 ceramics

A. Zaman 1,2 , A. Hussain 1 , T. K. Song 1 , M. H Kim 1* , Y. Iqbal 2 and W. J. Kim 3

1 School of Nano & Advanced Materials Engineering, Chanwon National University,

Gyeongnam 641-773, Republic of Korea

2 Materials Research laboratory, Institute of Physics and Electronics, University of Peshawar,

Peshawar, Pakistan

3 Department of Physics, Changwon National University, Gyeongnam 641-773, Republic of

Korea

* E-mail address of the corresponding author : mhkim@changwon.ac.kr

Lead-free Ta-modified 0.99[(Bi0.82Na18)TiO3-(Bi1/2K1/2)TiO3]-0.01LiSbO3 (BNKTT-LS)

piezoceramics were synthesized by a conventional solid-state reaction method. The effect Ta

addition into the BNKT-LS ceramics was investigated through X-ray diffraction, dielectric,

temperature dependent ferroelectric and field-induced strain characterizations. As the Ta

content was increased, the maximum dielectric constant as well as the depolarization

temperature (Td) decreased. The polarization and strain hysteresis loops indicate that the

addition of Ta significantly disrupts the ferroelectric order of the BNKT-LS ceramics leading

to a degradation of the remanent polarization and coercive field. However, the destabilization

of the ferroelectric order is accompanied by a significant enhancement in the unipolar strain.

A large unipolar field-induced strain of 0.38% with a normalized (d * 33 = Smax/Emax = 650

pm/V) at a driving field of 6 kV/mm was obtained at room temperature for x = 0.013. This

significant strain enhancement is a result of the reversible phase transition between a NP

phase in a zero field and a field-induced ferroelectric phase.

P- 66


Poster session II

Ferroelectric Properties of Potassium Sodium Niobium Oxides Ceramics

with Tetragonal and Orthorhombic Composite Structures

Byeong-Eog Jun 1* , Hyunjun Park 2 , Seongmun Eom 2 ,

Hyunsuk Yoon 2 , Suyeol Lee 2 and Dong Jin Kim 3

1 Department of Physics and Earth Science, Korea Science Academy of KAIST, Busan 614-

822, Korea

2 Korea Science Academy of KAIST, Busan 614-822, Korea

3 Department of Physics, Pusan National University, Busan 609-735, Korea

* E-mail address of the corresponding author : chai2jun@kaist.ac.kr

The alkaline niobates (K,Na,Li)NbO3 ferroelectric ceramics were prepared by applying

liquid phase sintering. For the ferroelectric tetragonal and orthorhombic composite structures

of potassium sodium niobium oxides, K1-yNayNbO3 with y = 0.3 (KNN3) and y = 0.7 (KNN7)

perovskite crystalline powders were prepared. In order to prepare the high density composite

ceramics, K3Li2Nb5O15 (KLN) tetragonal tungsten bronze (TTB) crystalline powder was

added to the mix of 0.5KNN3+0.5KNN7 perovskite crystalline powders. It is expected that

the KLN TTB crystalline powder results in the liquid phase sintering at the surface boundary

of the KNN perovskite crystalline grains during sintering the mixture specimen. KLN TTB

crystalline phase usually modified to the composition of K1-yNayNbO3 perovskite grains. It is

considered that the 0.5KNN3+0.5KNN7 composite ceramics showed a mixture of tetragonal

and orthorhombic structures. (K,Na,Li)NbO3 composite ceramics were considered to be the

Pe structure with two different K/Na ratios with y = 0.3 and 0.7 in the (1-z)K1-yNayNbO3 +

(z/5)KLN (z = 1, 2, 5 and 10) composite ceramics. We confirmed the ferroelectric tetragonal

and orthorhombic composite structures of (K,Na,Li)NbO3 ceramics by using the X-ray

diffraction technique and the ferroelectric D-E loop with the modified Sawyer-Tower circuits.

The dielectric properties were investigated for the unpoled (K,Na,Li)NbO3 composite

ceramics by using the impedance analyzer in the temperature range from room temperature to

600 °C. The possible hybrid effects were considered in order to enhance the piezoelectric

properties of the poled (K,Na,Li)NbO3 composite ceramics.

P- 67


Poster session II

Composition dependence of relaxor properties of (1-x)K0.5Na0.5NbO3 –

xBa0.5Ca0.5TiO3 ferroelectric ceramics

C.-W. Cho 1 , M. R. Cha 1 , J. Y. Jang 1 , S. H. Lee 1 , D. J. Kim 1 , J. S. Bae 2 , and S. Park 1*

1 Department of Physics, Pusan National University, Busan 609-735, Korea

2 Busan Center, Korea Basic Science Institute, Busan 609-735, Korea

* E-mail address of the corresponding author : psk@pusan.ac.kr

The Ba0.5Ca0.5TiO3 (BCT) composition dependent structural and dielectric properties of

(1-x)K0.5Na0.5NbO3 - xBa0.5Ca0.5TiO3 ceramics were investigated. Room temperature x-ray

diffraction revealed that the structure transforms from orthorhombic to cubic with increasing

BCT composition. The shift of maximum temperature of the maximum dielectric constant at a

particular frequency suggests that the system exhibits ferroelectric relaxor behavior. The

system containing 15 % BCT showed the closest calculated Curie-Weiss exponent to 2, which

the exponent for a relaxor ferroelectric.

Fig. (Left) Inverse dielectric permittivity at 1 MHz as a function of temperature for (1-x)KNN-xBCT ceramics

(symbols: experimental data; the solid line: fitting to the Curie-Weiss law). (Right) Log (1/ɛr - 1/ɛmax) at 1 MHz

for (1-x)KNN-xBCT ceramics (symbols: experimental data; solid line: fitting to the modified Curie-Weiss law)

as a function of the log (T- Tmax).

P- 68


Poster session II

Raman scattering study of relaxor ferroelectric Pb(Sc1/2Nb1/2)O3 crystals

Kouhei Suzuki 1* , Haruki Takayama 1 , Muhtar Ahart 2 ,

Alexei A. Bokov 3 , Zuo-Guang Ye 3 and Seiji Kojima 1

1 PAS, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

2 Geophysical Laboratory, Carnegie Institution of Washington, USA

3 Dep. Chem. and 4D LABS, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada

* E-mail address of the corresponding author : shamo.922@gmail.com

The vibrational properties of Pb(Sc1/2Nb1/2)O3 (PSN) relaxor-based ferroelectrics with

perovskite structure have been studied in this work. Polarized and depolarized Raman

scattering have been measured to investigate the ferroelectric phase transitions in slow-cooled

PSN with lead vacancies (PSN-V) and fast-cooled disordered PSN (PSN-DV), and

0.70Pb(Sc1/2Nb1/2)O3-0.30PbTiO3 (PSN-0.3PT) crystals as shown in Fig. 1. The mode

intensity, frequency, and depolarization ratio of Raman bands below 400 cm -1 exhibit the

remarkable temperature variation in the vicinity of Tm reflecting the change of crystal

symmetry. The difference of dynamics in the ferroelectric phase transitions among PSN-V,

PSN-DV, and PSN-30PT is discussed on the basis of degree of order on the B site and lead

vacancies on the A site of the perovskite structure.

-100 0 100

Frequency shift (cm

200 300

-1 )

P- 69

PSN-0.3PT

heating

350 o C

220 o 300

C

o C

75 o 180

C

o C

Fig. 1 Temperature dependence of Raman scattering spectra.

References

1. Y. Bing, Ph. D Thesis, 2005, Simon Fraser University.

2. M. Ahart, A. Hushur, Y. Bing, Z. Ye, R. J. Hemley, and S. Kojima, Appl. Phys. Lett. 94,

142906 (2009).

3. S. Kojima, S. Tsukada, Y. Hidaka, A.A. Bokov, and Z.-G. Ye, J. Appl. Phys. 109, 084114

(2011).


Poster session II

Domain structure observations of PMN-PT using a second harmonic

generation microscope

Hiroko Yokota 1* , Hokuto Usami 1 and Junichi Kaneshiro 2

1 Department of Physics, Chiba University, Chiba 263-8522, Japan

2 Laboratory for Comprehensive Bioimaging, RIKEN, Osaka 565-0874, Japan

* E-mail address of the corresponding author : yokota@physics.s.chiba-u.ac.jp

(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) is known as a prototype relaxor ferroelectric.

Between 30 and 40% of PT concentration, a morphotropic phase boundary (MPB) exists

which separates the PT-rich tetragonal and the PMN-rich rhombohedral phase. Since the

discovery of monoclinic phase by Noheda et al., the MPB is regarded as a bridging phase

which connects the tetragonal and rhombohedral phases and it explains a large

piezoelectricity around the MPB region by a polarization rotation model. Recently, a phase

mixture model has been proposed around the MPB region in the case of PZT and it is

important to reexamine the domain structure on PMN-PT. To achieve this aim, a second

harmonic generation microscope (SHGM) observation was carried out.

Figure 1 shows the optical system of SHG Microscope. To determine a crystal structure

from SHG images, a polarizer and an analyzer were put to change the polar direction of a

fundamental and an SH wave. Single crystal PMN-PT30% was used as a specimen. For the

quantitative analysis, a polarizer and an analyzer were rotated with a parallel configuration

and polar plot were obtained as a two dimensional image shown in Fig.2. Three different

patterns can be seen in Fig.2. Based on the domain boundary configuration, the crystal

structure of PMN-PT30% was determined as a monoclinic structure. An electric field was

applied and the domain structural analysis will be also discussed.

Fig.1 Optical system of SHGM Fig.2 Polarization dependence of PMN-PT30%

P- 70


Poster session II

Evidence of the monoclinic phase around the MPB region in PMN-PT

K. Kurushima 1 , K. Kobayashi 2 , Yoichi Horibe 3 and Shigeo Mori 2,*

1 Toray Research Center, Ohtsu, Shiga 520-8567, Japan

2 Department of Materials Science, Osaka Prefecture University, Sakai, 599-8531, Japan

3 Rutgers Center for Emergent Materials and Department of Physics & Astronomy, Rutgers

University, Piscataway, New Jersey 08854, USA.

* E-mail address of the corresponding author : mori@mtr.osakafu-u.ac.jp

Piezoelectric materials, which convert electrical energy into mechanical energy, are

important in medical imaging and telecommunication devices [1]. Many studies have been

done in order to understand origin of giant piezoelectric response appearing around the

morphotropic phase boundary (MPB) region [2]. Understanding the relationship between the

crystal structures and the giant piezoelectric response is extremely important because x-ray,

electron and neutron diffraction experiments revealed some evidences of a monoclinic phase

around MPB [2]. On the other hand, domain structures around MPB has been examined by a

transmission electron microscopic (TEM) and optical methods [3]. In this study,

microstructures around the MPB regions of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ((1-x)PMNxPT)

were focused on. (1-x)PMN-xPT exhibits the structural phase transition around x~0.3

from the rhombohedral R3m to the tetragonal P4mm phases, as the PT concentration (x)

increases. The boundary between the rhombohedral to the tetragonal structures locates on

x=0.3 and is regarded as the MPB. Here, we carefully investigated the nanoscale domain

structures of (1-x)PMN-xPT (x~0.32) by the TEM experiment [4]. Domain structures with

hierarchical inhomogeneities were found in the monoclinic phase near the MPB region at

room temperature. The domain structures are characterized as the nanoscale lamella-type

domain structures with the ~10 nm width inside the large banded domains due to the

tetragonal structures. In addition, we have thoroughly investigated scattering-vector

dependence of the domain contrasts by obtaining various dark-field images and determined

orientations of the polarization vectors in the nanoscaled lamella-type domain structures and

confirmed the existence of the monoclinic structure around the MPB region.

[1] S-E. Park and T. R. Shrout, IEEE trans. Ultrason. Ferroelectr. Freq. Control 4, 1140

(1997).[2] B. Nohed et al., Phys. Rev. B 61, 8687 (2000). Phys. Rev. B 63, 014103 (2000). R.

Schierholz et al., Phys. Rev. B 78, 024118 (2008). R. Guo et al., Phys. Rev. Lett., 84, 5423

(2000). [3] D. Woodward et al., Phys. Rev. B 72 104110 (2005). T. Asada and Y. Koyama,

Phys. Rev. B 75, 214111 (2007).[4] K. Kurushima and S. Mori, Transactions on Ultrasonics,

Ferroelectrics, and Frequency Control (in press), Materials Science and Engineering, 18,

092015 1-1-4 (2011)

P- 71


Poster session II

Acoustic phonon behavior in relaxor-based (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3

ferroelectrics studied by Brillouin scattering

Shinya Tsukada 1,2* , Yuki Hidaka 2 , Seiji Kojima 2 , Alexei A. Bokov 3

and Zuo-Guang Ye 3

1 Faculty of Education, Shimane University, Matsue, Shimane, 609-8504, Japan

2 Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573, Japan

3 Dpt. of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada

* E-mail address of the corresponding author : tsukada@edu.shimane-u.ac.jp

The ferroelectric phase transitions in relaxor-based ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3xPbTiO3

(PZN-xPT) crystals, with x = 0.07, 0.10, and 0.12, were investigated using inelastic

light scattering from a longitudinal acoustic (LA) phonon (Fig. 1). An acoustic anomaly in a

broad temperature range, which is a particular property of relaxor ferroelectrics[1,2], was

observed, and we described the anomalies in the LA phonon by assuming local piezoelectric

coupling inside polar nanoregions (PNR) which are surrounded by a non-polar matrix. On the

basis of local piezoelectric coupling[1,3], a relaxation time � and a dynamic characteristic

length L of the order-parameter (polarization) fluctuations were determined to be in the order

of 10 -13 s and 10 -9 m, respectively. The �� and L values increase sharply upon cooling from

high temperatures with a more gradual change occurring below the intermediate temperature

T * (~500K). This result implies that rapid growth of the polarization fluctuation above T *

becomes mild below T * . The flexion point of the growing process in an ergodic relaxor phase

can be related to the characteristic properties of relaxor-based solid solutions undergoing a

ferroelectric phase transition.

Intensity

Frequency Shift (GHz)

Cooling 403 K

4

2 LA LA

CP

0

-60 -30 0 30 60

Frequency Shift (GHz)

60

40

20

0

-20

-40

-60

Intensity

Cooling

Cooling 853 K

4

LA LA

0

-60 -30 0 30 60

Frequency Shift (GHz)

200 400 600 800

Temperature (K)

2

0

400.0

800.0

1600

2400

3000

[1] S. Tsukada and S. Kojima, Phys. Rev. B 78, 144106 (2008).

[2] J. H. Ko, D. H. Kim, S. Tsukada, S. Kojima, A. A. Bokov, and Z. G. Ye, Phys. Rev. B 82, 104110

(2010).

[3] S. Tsukada, Y. Hiraki, Y. Akishige, and S. Kojima, Phys. Rev. B 80, 012102 (2009).

P- 72

Figure 1. Contour map of inelastic light scattering

intensity from PZN-0.07PT crystal versus

temperature and frequency shift in x(z y+z)x

scattering geometry (FSR = 75 GHz, scan range

= 70.5 GHz). The temperature-dependent

inelastic scattering from the LA phonon is

clearly observed. The dark parts at 0 GHz

denote elastic scattering. The scattering was

measured upon cooling without a polarizer.


Poster session II

Ferroelectric-Relaxor Composites in Bi-Based Lead-Free Ceramics

Changhyo Hong, Jin-Kyu Kang, Hyoung-Su Han, Dae-Jun Heo and Jae-Shin Lee *

School of Materials and Engineering, University of Ulsan, Ulsan 680-749, Korea

* E-mail address of the corresponding author: jslee@ulsan.ac.kr

Recently, 0.82(Bi1/2Na1/2)TiO3-0.18(Bi1/2K1/2)TiO3 solid solution (BNKT) ceramics

attract great attention because of their large electric field-induced strains (EFIS) at

ferroelectric (FE)-nonpolar (NP) boundaries. However, a critical problem that hinders their

practical application to actuators is the fact that large stains in Bi-based lead-free ceramics are

obtained only at high electric fields sufficient to induce a NP-FE phase transition. To lower

the critical field (Ecrit) that can cause the NP-FE phase transition, FE-relaxor (RE) composite

ceramics were investigated in this study. Ceramic-ceramic composites were prepared by

embedding coarse FE BNKT particles in RE Sn-doped BNKT ceramics.

The electric field-induced strain behavior was compared between FE BNKT, RE

BNKT (6 mol% Sn-doped), and FE/RE composites. The normalized strain Smax/Emax of the FE

BNKT was 217 pm/V and the RE Sn-doped BNKT was 172 pm/V at 5 kV/mm. However, the

normalized strain of FE/RE composites with 30 % FE BNKT was enhanced up to 274 pm/V

at 5 kV/mm. This result indicates that the Ecrit can be lowered by structuring a FE-RE

composite, which is believed to enlighten a new way for finding new lead-free piezoelectric

with large strains.

P- 73


Poster session II

Dielectric and Piezoelectric Enhancement of New Ceramics with Artificial

MPB Engineering

Ichiro Fujii 1 , Kenta Yamashita 1 , Kouichi Nakashima 1 , Nobuhiro Kumada 1

Satoshi Wada 1* , Chikako Moriyoshi 2 and Yoshihiro Kuroiwa 2

1 Material Science and Technology, Interdisciplinary Graduate School of Medical and

Engineering, University of Yamanashi, 4-4-37 takeda, Kofu, Yamanashi 400-8510, Japan

2 Department of Physical Science, Hiroshima University, Higashihiroshima, Hiroshima 739-

8526, Japan

* E-mail address of the corresponding author : swada@yamanashi.ac.jp

Barium titanate (BaTiO3, BT) and potassium niobate (KNbO3, KN) (BT-KN) nanostructured

ceramics with artificial morphotropic phase boundary (MPB) structure were

successfully prepared by solvothermal method at temperatures below 230 ˚C. Various

characterizations confirmed that the BT-KN nano-structured ceramics exhibited BT/KN

molar ratio of 1, a porosity of around 30 % and heteroepitaxial interface between BT and KN.

Their apparent piezoelectric constant d33 * was estimated at 136 pC/N, and was three times

larger value than that of the 0.5BT-0.5KN dense ceramics. The concept proposed in this

study can be a new way to create piezoelectric ceramics with artificial MPB region.

Moreover, this method is very universal and applied into various functional materials such as

magnetic, conductive, semi-conductive, and optical materials in addition to dielectric,

piezoelectric and ferroelectric materials. In the future, we will develop various new

materials with heteroepitaxial interfaces on the basis of the concept.

P- 74


Poster session II

Electrical Properties of (Sr0.75,La0.25)TiO3 Ultra-thin Films

Seongtak Yoon 1 , EuiyoungChoi 1 , Yunsang Lee 2 and Jaichan Lee 1*

1 School of Advanced Materials Science and Engineering, Sungkyunkwan University,

Kyunggido, 440-746, Korea.

2 Department of Physics, Soongsil University, Seoul, 156-743, Korea.

* E-mail address of the corresponding author : jclee@skku.edu

The (Sr0.75, La0.25)TiO3 (SLTO) ultra-thin films with various thicknesses have been

grown on Ti-O terminated SrTiO3 (100) substrate using Laser-Molecular Beam Epitaxy

(Laser MBE). The film structure and topography were verified by atomic force microscopy

(AFM) and high resolution thin film x-ray diffraction by the synchrotron x-ray radiation. We

have also investigated the electronic band structure using x-ray absorption spectroscopy

(XAS). The ultra thin SLTO film exhibited thickness driven metal-insulator transition around

8 unit cell thickness when the film thickness was progressively reduced to 2 unit cell. The

SLTO thin films with an insulating character showed band splitting in Ti L3-L2 edge XAS

spectrum, which is attributed to Ti 3d band splitting. This narrow d band splitting could drive

the metal-insulator transition along with Anderson Localization. In optical conductivity, we

have found the spectral weight transfer from coherent part to incoherent part was observed

when the film thickness was reduced. This result indicates the possibility of enhanced

electron correlation in ultra thin films.

P- 75


Poster session II

Transport Properties of Low Dimensional La0.75Sr0.25VO3 Thin Films

Taejun Hwang 1 , Tran Minh Dao 1 , Partha S. Mondal 1 and Jaichan Lee 1*

1 School of Advanced Materials Science and Engineering, Sungkyunkwan University,

Kyunggido, 440-746, Korea.

* E-mail address of the corresponding author : jclee@skku.edu

The La0.75Sr0.25VO3 (LSVO) ultra-thin epitaxial films with various thicknesses (5 to 25

uc) were deposited on atomically flat (001) oriented LaAlO3 (LAO) substrate by pulsed laser

deposition. LSVO films with thickness larger than 8 uc exhibited metallic behavior and

underwent a metal-insulator transition (MIT) at thicknesses between 8 uc and 5 uc. Above the

critical thickness of 5 unit cell, metallic films exhibit a temperature driven metal-insulator

transition with weak localization behavior while LSVO with the nominal composition

exhibits correlated metal behavior. With decreasing film thickness, oxygen octahedron

rotation in the films increases, causing enhanced electron-electron correlation. The observed

MIT is attributed to early onset of electron-electron correlation, i.e., bandwidth narrowing

driven by the splitting of V 3d t2g band in low dimensional structures as well as Anderson

localization represented by the disorder parameter approaching to the Ioffe-Regel limit.

P- 76


Poster session II

Structural study of gradient lattice distortion in BaTiO3-KNbO3 composites

with heteroepitaxial interface

Eisuke Magome 1* , Yoshihiro Kuroiwa 1 , Hironori Yoshimura 1 , Chikako Moriyoshi 1 ,

Kenta Yamashita 2 , Ichiro Fujii 2 , Kouichi Nakashima 2 ,

Nobuhiro Kumada 3 and Satoshi Wada 2

1 Graduate School of Science, Hiroshima University, Hiroshima 739-8526, Japan

2 Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi,

Yamanashi 400-8510, Japan

3 Center for Crystal Science and Technology, University of Yamanashi, Yamanashi 400-8511,

Japan

* E-mail address of the corresponding author : magome@sci.hiroshima-u.ac.jp

Lead-free ferroelectric materials are of concern due to the environmental problems, and

are anticipated to be substituted for conventional ferroelectrics such as Pb(Zr,Ti)O3 ceramics.

Recently, we have found that solvothermally synthesized BaTiO3 (BT)-KNbO3 (KN)

composites with a heteroepitaxial interface show the fairly large piezoelectric constant

compared with sintered BT-KN composites in the normal way [1]. The enhancement in the

piezoelectric response would be attributed to the distinct interface, so that we consider that

promising lead-free ferroelectric materials are emerged in the process to develop such

composites with a heteroepitaxial interface. In this study, we have carried out the structural

study of the KN-BT composites to reveal the clear relationships between the crystal structures

of the interface and the dielectric property.

KN-BT composites with the KN/BT molar ratio of 0.5 were synthesized by solvothermal

method, in which the ceramic grain with homogeneous size-distribution is configurated with a

BT particle with a radius of 150 nm at the inner core covered with KN. Synchrotron radiation

powder diffraction data were collected using the large Debye-Scherrer camera installed at

SPring-8 BL02B2. The energy of X-rays was 18.5 keV (wave length ��= 0.669 Å). We

analyzed the crystal structure of the ceramic grain on the basis of the core/multi-shell model

using the Rietveld method. It is revealed that the BT particle is significantly distorted in the

large region to form the interface with KN through the gradually distorted region from the

tetragonal structure at the core toward the cubic structure at the boundary between BT and

KN. The volume of the distorted interface region is decreased and the piezoelectric response

is suppressed by annealing the composites at 1000ºC for 10 h. These experimental results

provide an evidence that the interface controls the ferroelectric properties of the composite

ceramics.

[1] I. Fujii et al. : Appl. Phys. Lett. 99 (2011) 202902.

P- 77


Poster session II

Characterization of BN doped BaTiO3 PTC thermister

Myoung Pyo Chun * and Sung Kyoung Hong

Korea Institute of Ceramic Engineering & Technology(KICET), Seoul 153-801, Korea

* E-mail address of the corresponding author : myoungpyo@kicet.re.kr

PTC thermister has been used as an over-current protector which is connected in series

with the circuit of electrical devices. So, it is required that PTC thermister has low resistance

at room temperature. BN doped (Ba0.998Sm0.002)TiO3 PTC thermisters (BN=0.02, 0.025, 0.03

mol) were synthesized by the solid state method and their disk samples of diameter 0.5mm

were prepared by firing at 1040 and 1060 o C in reduced atmosphere of 10%H2-90%N2 gas.

The electrical properties and the microstructure of the disk samples were obtained with the

impedance analyzer and SEM. With increasing BN content in (Ba0.998Sm0.002)TiO3, the

resistance at room temperature increases continuously, which seems to be related with the

thickness of BN-insulation layer at the grain boundary. The behavior of the resistance at room

temperature of the disk samples as a function of BN content in (Ba0.998Sm0.002)TiO3 PTC

thermister was investigated with Cole-Cole plot.

P- 78


Poster session II

Grain growth and piezoelectric property of (Na0.545K0.47)(Nb0.55Ta0.45)O3

with a sintering aid of Li2CO3 and MnO2 by template grain growth method

Da Jeong Kim 1 , Myang Hwan Lee 1 , Jin Su Park 1 , Dalhyun Do 1 , Myong-Ho Kim 1 ,

Sang Wook Kim 2 , Hae In Choi 2 , Sang Su Kim 2 , Won Jeong Kim 2

and Tae Kwon Song 1*

1 School of Nano and Advanced Material Engineering, Changwon National University,

Changwon 641-773, Korea

2 Department of Physics, Changwon National University, Changwon 641-773, Korea

* E-mail address of the corresponding author : tksong@changwon.ac.kr

Lead-free piezoelectric materials, K0.5Na0.5NbO3 (KNN) based ceramics, have been

carried out to improve the sinterability and piezoelectric properties. The addition of Li2CO3

and MnO2 as a sintering aid was found to improve the densification of ceramics and decrease

the sintering temperature of the ceramics.

In this poster, we investigated the addition of (Na0.545K0.47)(Nb0.55Ta0.45)O3 (NKNT)

piezoelectric ceramics with Li2CO3 and MnO2 sintering aid fabricated by a tape casting

method using a plate-like NaNbO3 particle. The microstructures and phase formation of the

textured NKNT thick films were investigated by a scanning electron microscopy and an X-ray

diffractometer, respectively. Within 2� = 20 o - 60 o , the orientation degree (F, Lotgering

factor) was calculated by a Lotgering method. Piezoelectric constant (d33) and dielectric

constants were measured with piezo d33 meter and an impedance analyzer, respectively.

P- 79


Poster session II

Structural analysis of lead free (Bi0.5Na0.5)TiO3 base ceramics

using Rietveld refinement method

Sang Wook Kim 1 , Hae In Choi 1 , Myang Hwan Lee 2 , Dalhyun Do 2 , Jin Su Park 2 ,

Da Jeong Kim 2 , Tae Kwon Song 2 , Myong Ho Kim 2 , Sang Su Kim 1

and Won Jeong Kim 1*

1 Department of Physics, Changwon National University, Changwon 641-773, Korea

2 School of Nano & Advanced Materials Engineering, Changwon National University,

Changwon, Gyeongnam 641-773, Korea

* E-mail address of the corresponding author : kwj@changwon.ac.kr

Lead-based piezoelectric ceramics with a perovskite, such as Pb(Zr,Ti)O3, are widely

used for actuators, sensors and microelectronic devices because of their excellent

piezoelectric properties. However, the toxicity of lead and its high vapor pressure during

processing have led to a demand for alternative lead-free piezoelectric materials that are

environmentally benign from the viewpoint of sustainable development. The (Bi0.5Na0.5)TiO3

(BNT) materials have been developed as a promising lead-free piezoelectric material for

environmentally benign good piezoelectric devices.

In this study, the BNT-based ceramics were formed using a solid state reaction method.

Structure of the BNT-based ceramics was analyzed by a Rietveld refinement with X-ray

diffraction data. The result was compared to that of the Cohen’s method. More detailed fitting

procedures and results will be discussed in the presentation.

P- 80


Poster session II

Lithium doping in the Gallium and Magnesium modified Zinc Oxides

Byeong-Eog Jun 1 , Dongwon Jang 2 , Sungwon Ha 2 , DongHyuk Choi 2 , Hui Jung 2

and Byung Chun Choi 3*

1 Department of Physics and Earth Science, Korea Science Academy of KAIST,

Busan 614-822, Korea

2 Korea Science Academy of KAIST, Busan 614-822, Korea

3 Department of Physics, Pukyong National University, Busan 608-737, Korea

* E-mail address of the corresponding author : bcchoi@pknu.ac.kr

The Li-doped modified zinc oxide Zn1-xMexO:Li (Me = Ga, Mg) ceramics were studied

for the transparent conductive oxide thin films on Al2O3 (0001) substrate. The Li doping was

considered for the modified ZnO to show a p-type semi-conductive properties by using the

Zn1-xMexO:Li ceramics targets with Li contents of 0.05 at%, and 0.10 at%. Where, the Ga

modification was confirmed to contribute to the n-type conductivity of Zn1-xGaxO:Li

(ZGO:Li) thin films. Li content may contribute to increase the electron mobility in the

ZGO:Li thin films when compared to the ZGO thin films. We also consider that Li doping in

the Zn1-xMgxO (ZMO:Li) ceramics. Where, x ranges from 0 to 0.5 while maintaining Li

contents of 0.5 at% and 0.1 at%. ZMO:Li ceramics were characterized by using the X-ray

diffraction, the scanning electron microscopy. We investigate the preparations of ZGO:Li and

ZMO:Li target ceramics for the pulsed laser deposition or DC magnetron sputtering

techniques. The main issue is about the p-type conduction by doping Li in the ZGO and ZMO

host materials. Usually, Ga 2+ ion in the Zn site contribute negative excess charges while Mg 2+

ions show a neutral substitution for Zn sites. Therefore, we expect that Li doping may

contribute to the p-type conduction in the ZMO host materials. Although we considered the Li

doping is a minor contribution to the ZGO host material, the extrinsic contribution to the ntype

conduction is expected at the grain boundary in the ZGO:Li thin films.

P- 81


Poster session II

Low-Temperature Synthesis of (Na,K)NbO3 by Dissolution-Precipitation

Method

Kengo Shibata, Seiji Yamazoe* and Takahiro Wada

Department of Materials Chemistry, Ryukoku University, Otsu 520-2194, Japan

* E-mail address of the corresponding author : yamazoe@rins.ryukoku.ac.jp

Low-temperature synthesis of (Na,K)NbO3 (NKN) attracts much attention in the leadfree

ferroelectric field. Some low temperature synthesis methods were reported, such as solgel

method and hydrothermal method. However, these synthesis methods have some

restrictions such as expensive raw materials and high-pressure vessel. In the present study, we

provide a new low-temperature synthesis method of NKN by a simple dissolutionprecipitation

method. We found that the morphology of the NKN crystals could be controlled

by this method.

First, we synthesized Na3NbO4 precursor from Nb2O5, Na2C2O4 and (NH2)2CO by a

modified solid solution method at 800

Fig.1 SEM micrographs of

(a) Na7(H3O)Nb6O19 ·14H2O

intermediate crystals,and

(b) (Na0.5K0.5)8Nb6O19·9H2O

intermediate crystals.

o C. The Na3NbO4 precursor was dissolved in aqueous

buffer solutions of pH = 7 (KCl + HCl). The pH of the solution was increased by the addition

of NaOH and/or KOH solution. When the pH of the solution increased up to pH = 13, white

powder was precipitated. The obtained white powder was separated by filtration and dried at

100 o C for 10 min. Then, the dried powder was heated at 500 o C for 4 h in air. The obtained

sample was analyzed by powder X-ray diffraction (XRD) and scanning electron microscope

(SEM).

XRD analysis showed that the white powders

obtained using NaOH and using NaOH: KOH = 1: 1

solution are Na7(H3O)Nb6O19·14H2O and

(Na0.5K0.5)8Nb6O19·9H2O, respectively. Figures 1 (a) and

(b) show the SEM images of Na7(H3O)Nb6O19·14H2O and

(Na0.5K0.5)8Nb6O19·9H2O crystals, respectively. The

Na7(H3O)Nb6O19·14H2O crystals have needle-like and the

(Na0.5K0.5)8Nb6O19·9H2O crystals have plate-like

morphologies. This result showed that the Na/K ratio of

the solution is important for controlling the composition

and morphology of crystals. We confirmed that needlelike

NaNbO3 and plate-like (Na0.5K0.5)NbO3 are obtained

by heating needle-like Na7(H3O)Nb6O19·14H2O and platelike

(Na0.5K0.5)8Nb6O19·9H2O, respectively.

P- 82


Poster session II

O2 Annealing Effect on KF-Substituted BaTiO3 Ceramics

Masahiko Bekki 1* , Junnya Ikeda 2 , Shinya Tsukada 1,2 and Yukikuni Akishige 1,2

1 Graduate school of Education, Shimane University, Matsue city, Shimane 609-8504 , Japan

2 Faculty of Education, Shimane University, Matsue city, Shimane 690-8504, Japan

* E-mail address of the corresponding author : E129209@matsu.shimane-u.ac.jp

Recent concern over the environment requires the development of lead-free piezoelectric

materials. We have reported that lead-free KF-substituted BaTiO3 (Ba1-xKxTiO3-xFx: KF-BT/x)

single crystals with x~ 0.10 show favorable piezoelectric and dielectric properties (d33 ~ 300

pC/N, �’~ 10000 at room temperature) [1, 2]. In the present stage, it is interesting to fabricate

ceramic forms of KF-BT/x. As we reported that F in KF-BT/x evaporates easily and changes

the properties [3], it is necessary to avoid the evaporation of F. So we prepared the ceramics

by Spark Plasma Sintering (SPS) method which can sinter ceramics in a short time (~ 10 min)

with fast heating/cooling rates [4]. However, ceramics after sintering by SPS method needs

annealing to compensate vacancies, and the annealing process results in adverse effect. In the

present study, we investigate appropriate annealing condition to fabricate high quality KF-

BT/0.10 ceramics.

TC, a benchmark how much F evaporates [3], of

KF substitution ratio : x

each KF-BT/0.10 ceramics after annealing was 0.1 0.09 0.08 0.07 0.06

400

determined by dielectric measurement and is shown in

Fig. 1. TC increases as annealing temperature (TA)

350

increases, which is consistent of the result of single

crystals. This result indicates that annealing at TA~

300

1073 K is the most favorable for KF-BT/0.10

ceramics from a standpoint of TC. If we assume that

250

change in TC is all attributed to the evaporation of F,

1100 1200 1300 1400

TA (K)

the amount of evaporation is expressed by the solid

Figure 1.T vs. T C A (bottom), x (upper)

line in Fig. 1 where the solid line was obtained from of KF-BT/0.10. The solid line is

the x dependences of TC in single crystals [2].

obtained from Ref. 2.

[1] Y. Akishige : J. Phys. Soc. Jpn. 75 (2006) 073704.

[2] Y. Akishige : Ferroelectrics 369 (2008) 91.

[3] S. Tsukada and Y. Akishige : Scripta Mater. 64 (2011) 268.

[4] Y. Akishige, K. Honda, and S. Tsukada : Jpn. J. Appl. Phys. 49 (2010) 09MC03.

P- 83

TC (K)


Poster session II

Crystal structures and polarization/piezoelectric properties of ferroelectric

(Bi0.5K0.5)TiO3–(Bi0.5Na0.5)TiO3 Single Crystals

Ken Yanai 1 , Akifumi Morishita 1 , Yuuki Kitanaka 1 , Yuji Noguchi 1* ,

Masaru Miyayama 1 , Chikako Moriyoshi 2 , Yoshihiro Kuroiwa 2 , Shuki Torii 3

and Takashi Kamiyama 3

1 RCAST, The University of Tokyo, Tokyo 153-8904, Japan

2 Department of Physical Science, Hiroshima University, Hiroshima 739-8526, Japan

3 High Energy Accelerator Research Organization, Ibaraki 319-1106, Japan

* E-mail address of the corresponding author : ynoguchi@crm.rcast.u-tokyo.ac.jp

Bi-based ferroelectric perovskites have attracted a great deal of attention from scientific

and technological points of view. Considerable efforts have been devoted to developing highperformance

piezoelectric ceramics for e.g. the x(Bi0.5K0.5)TiO3–(1−x)(Bi0.5Na0.5)TiO3

[xBKT–BNT] system 1), 2) but there are few reports on single crystals of xBKT–BNT,

probably because of technical difficulty in growing crystals due to high vapor pressures of Bi

and K at high temperatures. In this study, high-quality single crystals of xBKT–BNT were

grown by the high-oxygen pressure top-seeded solution

growth method, 5) and the polarization and piezoelectric

properties were investigated. The crystal structures were

analyzed by single crystal synchrotron x-ray diffraction

(XRD) obtained at SPring-8 BL02B1 and high-resolution

neutron powder diffraction (NPD) measured by

SuperHRPD at KEK.

Figure 1 shows the lattice parameters and

tetragonalities (c/a) of xBKT–BNT refined by the NPD

Rietveld analysis. The following phase diagram for the

xBKT–BNT system (unpoled, i.e., without electric field) is

proposed : x = 0–0.20 ; rhombohedral (R3c, R) , x = 0.30–1.0 ;

tetragonal (P4mm, T), x = 0.20–0.30 ; the mixture (R and T) of

R3c and P4mm. Single-crystal XRD analysis confirmed the

phase diagram shown in Fig .1.

Figure 2 shows the in-situ XRD spots for 0.48BKT–BNT

crystals under applying electric fields : (a) E = 0 kV/cm (after

poled at E = −60 kV/cm), (b) E = +30 kV/cm, (c) E

= +80 kV/cm. The dynamics of 90-deg domains

were clearly revealed as follows: I. main 412 and

sub 124 spots due to the presence of 90-deg

domains were observed; II. polarization switching

was accomplished through the rotation of 90-deg

domains ; III. the 90-deg domain rotation was

induced below coercive field EC (40 kV/cm).

1) Y. Hiruma et al., J. Appl. Phys., 103, 084121

(2008). 2) K.Yoshiiet al., Jpn. J. Appl. Phys.,45(5B), 4493-4496 (2006). 3) A. Morishita et al.,

J. Adv. Dielectr., 1, 63–69, (2011). 4) R. Sun et al., J. Appl. Phys., 109, 124113 (2011). 5)Y.

Kitanaka et al., Ferroelectrics, 414, 24 (2011).

P- 84

3), 4)

Fig.1. Lattice parameters and

tetragonalities and a phase diagram

of xBKT–BNT.

Fig. 2. P-Ehysteresisloop and in-situ x-ray

diffraction patternsunder applying various

electric fields of 0.48BKT–BNTsingle

crystals.


Poster session II

Density functional theory study of paraelectric-ferroelectric phase

transition of polyvinylidene difluoride

Won-June Kim 1 , Won Joon Heo 1 , Myunghoon Han 1 , Young-Han Shin 2

and Eok Kyun Lee 1*

1 Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon

305-701, Korea

2 Department of Physics and Chemistry and EHSRC, University of Ulsan, Ulsan 680-749,

Korea

* E-mail address of the corresponding author : eklee@kaist.ac.kr

Since the well-known ferroelectric Pb(Zr,Ti)O3 (PZT) is environmentally hazardous due

to the toxic element Pb, lead-free inorganic ferroelectric perovskites such as BiFeO3 and

(K,Na)NbO3 and organic ferroelectrics such as polyvinyledene difluoride (PVDF) have been

suggested as promising candidates for future ferroelectric and piezoelectric materials. Even

though PVDF shows worse ferroelectric and piezoelectric properties than PZT, it has been

used in many applications thanks to its high flexibility and lightness. Among the five phases

(α, β, γ, δ and ε phases) of PVDF, the paraelectric α phase and the ferroelectric β phase are the

main interesting phases. The β phase can be synthesized from α phase by mechanical drawing

and electrical poling, but the mechanism for this transition has not been fully understood yet.

Some theoretical studies on α-β phase transition have been carried out using unit cell model,

but these models cannot account for the nucleation and propagation in a polymeric chain. In

our study, therefore, we firstly perform static density functional theory calculations to observe

the total energy of each α and β phases as a function of the lattice parameters in the

orthorhombic structure. The energy barrier between the two phases is roughly estimated to be

about 0.1 eV per PVDF monomer (C2H2F2). Identifying the reaction path connecting the

ground states of the α and β phases and the estimated transition state, we confirm that

mechanical drawing along the PVDF chain axis is essential for the α-β phase transition.

Secondly, we perform ab-initio molecular dynamics (AIMD) and nudged elastic band (NEB)

simulations for the single-chain PVDF to understand the aperiodic dynamics of the α-β phase

change. From the Fourier analysis of the time series of polarization, we find that the phonon

modes corresponding to dihedral angles change during the phase transition.

P- 85


Poster session II

First-principles study of piezoelectric and dielectric properties of a

graphene-based dipolar layer

Hye-Jung Kim and Young-Han Shin *

Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749, Korea

* E-mail address of the corresponding author : hoponpop@ulsan.ac.kr

By selectively controlling hydrogenation and fluorination of graphene, the inversion

symmetry of a graphene layer can be broken. It allows induction of the spontaneous

polarization or piezoelectric properties [1]. For the hydrogenated and fluorinated graphene

(C2HF), which hydrogen atoms are attached from the top of a graphene layer and fluorine

atoms from the bottom of the layer in an ideal condition, four different C2HF conformations

are generated by attached atoms, which are referred to as chair, boat, zigzag, and armchair

conformations. We examine the stability of these C2HF conformations by calculating the

formation energies of them, and confirm that the four conformations are energetically stable

and the chair conformation is the most stable of them all. For the chair C2HF layer, the

spontaneous polarization PS along the direction perpendicular to the layer is computed as 47.3

pC/m in terms of the Berry phase calculation [2]. In order to investigate the possibility of this

C2HF layer structure in device applications, we propose a simple structure that a chair C2HF

layer is inserted between two graphene single layers, and study the characteristic changes in

structural and electronic properties. All calculations have been performed within densityfunctional

theory (DFT) formalism.

[1] M.T. Ong, and E.J. Reed, ACS Nano 6, 1387 (2011).

[2] R.W. Nunes, and X. Gonze, Phys. Rev. B 63, 155107 (2001).

P- 86


Poster session II

Piezoelectricity and elasticity of hydrogenated boron nitride monolayer

Md. Noor-A-Alam, Hye Jung Kim and Young-Han Shin *

Department of Physics, University of Ulsan, Ulsan 680-749, Korea

* E-mail address of the corresponding author : hoponpop@ulsan.ac.kr

Having been noncentrosymmetric, a hexagonal boron nitride monolayer, in contrast to

graphene, is a piezoelectric. But it shows neither in-plane nor out-of-plane dipole moment due

to its complete flatness and three fold symmetry on the plane [1]. However, hydrogenation

distorts the flatness and introduces out-of-plane dipole moment for chair form of

hydrogenated boron nitride, while boat form has no out-of-plane dipole due to its atoms’

position in the unit cell. Consequently chair form of hydrogenated boron nitride monolayer

shows both in-plane and out-of-plane piezoelectric responses while pristine hexagonal boron

nitride monolayer has only an in-plane piezoelectric response. For a two-dimensional

hydrogenated boron nitride monolayer with trigonal (3m) symmetry, there is a vacuum region

along the direction perpendicular to the sheet (the z-direction), so nonzero piezoelectric stress

coefficients are e31, e32, e11, e12, and e26 in voigt notation where e31=e32 and e11=-e12=-1/2e26.

The same symmetry analysis holds for the piezoelectric strain coefficients (dij). In this work,

we compute independent piezoelectric coefficients (e11, e31, d11, and d31) for the chair form of

hydrogenated boron nitride by using the density functional theory calculations, and find that

our piezoelectric response is quite comparable with PVDF and its copolymers, and also with

recently discovered engineered piezoelectric graphene [2]. We also calculate the independent

elastic stiffness constants (C11 and C12) for the two-dimensional hydrogenated boron nitride

monolayer and observe that hydrogenation, because of the change in hybridization of boron

and nitrogen atoms, lowers the stiffness of the sheet. Such a piezoelectric two-dimensional

hydrogenated boron nitride monolayer can be a candidate material for various nanoelectromechanical

applications.

[1] Na Sai and E. J. Mele, Phys. Rev. B 68, 241405(R) (2003).

[2] M.T. Ong, and E.J. Reed, ACS Nano 6, 1387 (2012).

P- 87


Poster session II

Atomic displacement of Tetragonal PbTiO3 with different

high electric field directions

Gantsooj Amarsanaa and Ill Won Kim*

Department of Physics and Energy Harvest-Storage Research Center,

University of Ulsan, 680-749, Ulsan, South Korea

* E-mail address of the corresponding author : kimiw@mail.ulsan.ac.kr

Recently, piezoelectric response of epitaxial constrained Pb(Zr0.2Ti0.8)O3 thin films using

novel approach in which dielectric breakdown was avoided by using ultra-short pulse of

electric field. This allowed access too much larger electric fields than previous possible, up to

about 500 MV/m compared with ~50 MV/m studied in earlier experiments. We displaced Ti

atom slightly 0.01 alone z axis in reduced coordinate after several interaction cubic PbTiO3

transfer to tetragonal PbTiO3. The dependence of atomic displacements is almost linear range

up to 500 MV/m in electric field directed to tetragonal axis in the reduced coordinate. In this

work, we calculated the atomic displacements of ferroelectric PbTiO3 by using the first

principle method and also investigated high electric field to tetragonal PbTiO3 at different

directions of electric field using Berry phase method and ABINIT package.

P- 88


Poster session II

Energy-band alignment and orbital-selective charge transfer at oxygendeficient

LaAlO3/SrTiO3(001) interfaces

P. V. Ong 1 and Jaichan Lee 1*

1 School of Advanced Materials Science & Engineering, Sungkyunkwan University,

Suwon, 440-746, Korea

* E-mail address of the corresponding author : jclee@skku.edu

Density-functional theory (DFT) within the local density approximation (LDA) +

Hubbard U and the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional approaches were

used to study the energy-band alignment and electronic states in stoichiometric and oxygendeficient

LaAlO3/SrTiO3 superlattices with regularly spaced n-type and p-type interfaces. We

found that the band alignments at the interfaces of the LAO/STO superlattices are of type II

band lineups with small valence-band offsets. Fundamental asymmetric behaviors between

the complementary n-type and p-type interfaces were revealed. Oxygen vacancies are more

electrostatically favorable at the p-type interface than at the n-type one. The extra electrons

induced by the oxygen vacancies at the p-type interface strongly spread to the n-type interface

and occupy the Ti 3d xy orbitals, while those induced by the vacancies at the n-type interface

are strictly confined and reside in Ti

3d 2 2 and/or 3 2 2

x � y

z r

P- 89

d 3 �

orbtials. Implications and

applications of the results on the LaAlO3/SrTiO3 multilayers and heterostructures with single

n- or p-type interface are discussed in detail.


Poster session II

Ferroelectric phase transition of AgNbO3: a first-principles study

Hiroki Moriwake 1,* , Craig A. J. Fisher 1 , Akihide Kuwabara 1 and Desheng Fu 2

1 Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, JAPAN

2 Shizuoka University, Hamamatsu, JAPAN

* E-mail address of the corresponding author : moriwake@jfcc.or.jp

AgNbO3 exhibits an anti-ferroelectric phase transition to an orthorhombic Pbcm phase at

around 340 K. Recently, Fu et al. 1 reported on the ferroelectric behavior of this compound.

However, its ferroelectric structure is still not well understood. Levin et al. 2 reported the

ferroelectric phase of AgNbO3 to also have Pbcm symmetry, attributing its ferroelectricity to

local symmetry breaking and/or a defective structure. More recently, Yashima et al. 3

proposed space group Pmc21 for the ferroelectric phase based on converged beam electron

diffraction and neutron and X-ray diffraction results. Here we report first-principles

calculations of the ferroelectric phase of AgNbO3 using the projector augmented wave

method based on density

functional theory. The

calculated phonon

dispersion curve of the

room temperature Pbcm

phase is shown in fig. 1.

No softmode is evident

over all wave vectors,

indicating that the Pbcm

phase has a dynamically

stable structure. The

ferroelectric behavior of

AgNbO3 thus cannot be

explained based on this.

Extensive calculations are

under way to uncover the

correct ferroelectric

transition mechanism of

this compound.

References

1. D. Fu, et al., Appl. Phys. Lett. 90, 252907 (2007).

2. L. Levin, et al., Phys. Rev. B 79, 104113 (2009).

3. M. Yashima, et al., Chem. Mater. 23, 1643 (2011).

Figure 1. Phonon dispersion curve for the room temperature

phase (Pbcm) of AgNbO3.

Acknowledgements

This work was supported by Green network of excellence (GRENE).

P- 90


Author Index


Author Index : Name and Abstract

(A)

Ahmed I. Ali P- 36

Atsushi Ashida P- 25

Chang Won Ahn I- 8, P- 2, P- 3, P- 18,

P- 27, P- 35, P- 37,

P- 61

Gantsooj Amarsanaa P- 88

H. Adachi P- 23

J. S. Ahn P- 43

Jun Akedo I- 20

Md. Noor-A-Alam P- 87

Muhtar Ahart P- 69

Yukikuni Akishige P- 83

(B)

Alexei A. Bokov I- 16, P- 69, P- 72

Insung Bae I- 4

J. S. Bae P- 68

Masahiko Bekki P- 83

Sang Don Bu P- 21

Shuvrajyoti Bhattacharjee P- 31

Sunggi Baik P- 4, P- 44

(C)

Byung Chun Choi P- 81

C.I. Cheon P- 60

C.-W. Cho P- 68

DongHyuk Choi P- 81

EuiyoungChoi P- 75

H. I. Choi P- 14

Hae In Choi P- 15, P- 58, P- 79, P- 80

J. H. Choi P- 60

jin Ho Choi P- 37

Jinsik Choi P- 50

K. W. Chae P- 60

Kang Ho Choi P- 18

M. R. Cha P- 68

Myoung Pyo Chun P- 78

Pice Chen I- 14

Seong Kyu Cheon P- 1

Song A Chae P- 2, P- 3, P- 18

S-W. Cheong PL-1, P- 45, P- 46

Taekjib Choi P- 50

Yong-Jai Cho P- 4

(D)

D. Do P- 14, P- 59

Dalhyun Do P- 15, P- 44, P- 58, P- 79,

P- 80

Eric M. Dufresne I- 14

Feng Dang C- 3

Matthew Dawber I- 14

Thi Hinh Dinh P- 27

Tran Minh Dao P- 76

(E)

Paul G. Evans I- 14

Seongmun Eom P- 67

(F)

Craig A. J. Fisher P- 90

Desheng Fu P- 90

Eiji Fujii I- 12

H. Funakubo P- 22

Hironori Fujisawa P- 38, P- 39, P- 48,

P- 49

Hiroshi Funakubo I- 7, P- 12

Ichiro Fujii P- 63, P- 74, P- 77

John G. Fisher C- 5

M. Fukada P- 23

M. Fukunaga P- 47, P- 55

N. Fujimura P- 26

Norifumi Fujimura P- 25

S. Fujiyama P- 47

S. Furukawa P- 45

Yuto Fujita P- 34

(G)

E. A. Goremychkin P- 45

T. Guidi P- 45

(H)

A. Hussain C- 7, P- 28, P- 59, P- 66

Ali Hussain P- 57

C. Hyon P- 55

Chang Jo Han P- 20

Changhyo Hong P- 73

Cheol Seong Hwang C- 4, P- 7, P- 13

Dae-Jun Heo P- 27, P- 73

H. Hiraka P- 47

Hajime Haneda C- 3

Hyoung-Su Han I- 8, P- 27, P- 57, P- 73

Jin Kyu Han P- 21

Motoaki Hara I- 10

Myunghoon Han P- 85

Sahwan Hong P- 50

Seung Ho Han P- 37

Suck Won Hong I- 3

Sung Kyoung Hong P- 78


Sung-Ok Hwang P- 40

Sungwon Ha P- 81

Taejun Hwang P- 76

Tsukasa Hirayama I- 18

Won Joon Heo P- 85

Y. Horibe C- 1, P- 46

Yoichi Horibe P- 71

Yoon-Hwae Hwang I- 3

Yuki Hidaka P- 72

(I)

Hikaru Igawa P- 52

Hiroaki Imai C- 3

Jun Ikeda P- 33

Junnya Ikeda P- 83

Kei Iwamoto P- 52

Makoto Iwata P- 30

Masafumi Iwaki I- 10

Masashi Igawa P- 39

Mitsuru Itoh I- 15

Mutsuo Ishikawa I- 7

N. Ikeda C- 1

Noriyuki Inoue P- 32

Shotaro Ishikawa P- 8

Takahiro Ishii P- 54

Y. Iqbal P- 66

Yoshihiro Ishibashi P- 30

Yoshihisa Ishikawa P- 56

Yuichi Ikuhara I- 18

(J)

Anquan Jiang P- 7

Byeong-Eog Jun P- 67, P- 81

Byung Chul Jeon I- 6, P- 16

Dae-Yong Jeong P- 62

Dongwon Jang P- 81

Doo Seok Jeong P- 7

Gun Sang Jeon P- 45

Ho-Young Joo P- 50

Hui Jung P- 81

J. Y. Jang P- 68

Jaehong Jeong P- 45

Ji Young Jo I- 14, P- 17, P- 20

Jihoon Jeon P- 50

Jin Suk Jeong P- 16

Jong Hoon Jung P- 6

Jong Shik Jang P- 4

Seong Su Jeong P- 1

W. Jo C- 2, P- 43

(K)

Akihide Kuwabara P- 90

Akihiro Kohori I- 9

Akitoshi Koreeda P- 53

Chang Soo Kim P- 4

Chiaki Kobayashi P- 49

D. J. Kim P- 14, P- 68

Da Jeong Kim P- 15, P- 58, P- 79, P- 80

Dong Jin Kim P- 67

H. J. Kim P- 41, P- 42

H. Kimura P- 47

Hajime Kishi P- 38

Han Joon Kim C- 4, P- 7, P- 13

Ha-Nul Kim C- 5

Hiroyuki Kimura P- 56

Hye-Jung Kim P- 86, P- 87

Hyo Kyeom Kim C- 4, P- 13

Ill Won Kim I- 8, P- 2, P- 3, P- 18, P- 35,

P- 37, P- 61, P- 88

Isao Kagomiya C- 6

Isao Kagomiya P- 9

J. S. Kim C- 7, P- 28, P- 60

J. W. Kim P- 22, P- 41, P- 42

Jae-Hyeon Ko I- 16, P- 35, P- 65

Jin Ho Kwak P- 21

Jin-Kyu Kang P- 73

Jin-Soo Kim P- 50

Jongdae Kim P- 5

Junichi Kaneshiro P- 70

K. Kobayashi P- 46, P- 55, P- 71

K. Komaki P- 23

K. Kurushima P- 46, P- 71

Kazumi Kato C- 3

Ken-ichi Kakimoto C- 6, P- 9

Kensuke Kato C- 6

Kyung Joong Kim P- 4

M. H. Kim C- 7, P- 14, P- 28, P- 41,

P- 42, P- 59, P- 66

Makoto Kuwabara C- 3

Masafumi Kobune P- 38, P- 48, P- 64

Minoru Kurosawa I- 7

Myong Ho Kim P- 1, P- 15, P- 44, P- 58,

P- 79, P- 80

Na Lee Kim P- 1

Nobuhiro Kumada P- 63, P- 74, P- 77

R. Kumai P- 55

Richard Hahnkee Kim I- 4

Ryo Kishimoto P- 38

S. S. Kim P- 41, P- 42

S. W. Kim P- 14

S.-A. Kim P- 47

Sadaharu Kato P- 30

Sang Su Kim P- 15, P- 58, P- 79, P- 80


Sang Wook Kim P- 15, P- 58, P- 79,

P- 80

Satoshi Kimura P- 38

Seiji Kojima I- 16, P- 34, P- 35, P- 52,

P- 54, P- 65, P- 69, P- 72

Seok Ju Kang I- 4

Sergei V. Kalinin P- 50

Shin-Ae Kim P- 45

T. Kanashima P- 11

Tae Heon Kim I- 6, P- 10, P- 16,

Tae Hyun Kim I- 16, P- 34, P- 35, P- 65

Takashi Kamiyama P- 84

Takeyuki Kikuchi P- 38

V. Kiryukhin P- 45

W. J. Kim C- 7, P- 14, P- 28, P- 41,

P- 42, P- 59, P- 66,

Won Jeong Kim P- 15, P- 44, P- 58,

P- 79, P- 80

Won-June Kim P- 85

Y. J. Kim P- 41, P- 42

Y. Kawahara P- 26

Yong Baek Kim P- 45

Yong Soo Kim P- 36

Yong Su Kim P- 16

Yoshihiro Kuroiwa P- 8, P- 31, P- 32,

P-33, P- 74, P- 77,

P- 84

Yoshihisa Kato I- 12

Yu Jin Kim C- 4, P- 7, P- 13

Yukihiro Kaneko I- 12

Yunseok Kim P- 50

Yuuki Kitanaka P- 8, P- 84

(L)

C. Lefevre C- 2

C.-H. Lee P- 47

Dae-Gi Lee C- 5

Daesu Lee I- 6, P- 16

Eok Kyun Lee P- 85

Hee Young Lee P- 40

Ho Nyung Lee I- 14

Hosang Lee P- 50

Ho-Yong Lee C- 5

Hyeon Jun Lee P- 17

Hyun-Young Lee P- 57

J. Lin P- 47

Jae-Shin Lee I- 8, P- 27, P- 57, P- 73

Jaichan Lee I- 13, P- 75, P- 76, P- 89

Jai-Yeoul Lee P- 40

Jeong Keun Lee P- 62

Jeong-Pyo Lee P- 4

Jong-Pil Lee P- 62

Jung Hoon Lim P- 1

M. H. Lee P- 14

Myang Hwan Lee P- 15, P- 16, P- 44,

P- 58, P- 79, P- 80

S. H. Lee P- 68

S.Y.Lim P- 59

Seongsu Lee P- 45

Soo Whan Lee P- 62

Sun-Young Lee P- 37

Suyeol Lee P- 67

Woo Lee P- 4

Xifa Long I- 16

Yunsang Lee P- 75

Yun-Soo Lim P- 62

(M)

Abdel Moez P- 36

Akifumi Morishita P- 84

C. Meny C- 2

Chikako Moriyoshi P- 8, P- 31, P- 32,

P- 33, P- 74, P- 77,

P- 84

Eisuke Magome P- 33, P- 77

Hiroki Moriwake I- 15, P- 31, P- 90

Ken-ichi Mimura C- 3

Masaki Maeda P- 30

Masaru Miyayama P- 8, P- 84

Michio Miura I- 10

Partha S. Mondal P- 76

Rizwan Ahmed Malik P- 57

Ryuta Mitsui P- 63

S. Mori C- 1, P- 46

Seung Eon Moon P- 5

Shigeki Miyasaka P- 56

Shigeo Mori P- 71

Takashi Matsuda I- 10

Tatsuya Mori P- 52

(N)

Dieu Nguyen C- 5

Hiroshi Nishioka P- 38, P- 64

K. Nakajima P- 45

K. Nishida P- 22

Kouichi Nakashima P- 63, P- 74, P- 77

S. Nakashima P- 11

Seiji Nakashima P- 38,P- 39, P- 48,

P- 49

Serge M. Nakhmanson I- 14

Sin-Hye Na I- 11

T. Nagata C- 1

T. Nakao P- 23


Tae Won Noh I- 6, P- 12, P- 16

Takahiro Nakano P- 56

Tea Won Noh P- 10

Tokihiro Nishihara I- 10

Van Quyet Nguyen P- 27, P- 57

Y. Noda P- 47, P- 55

Yu Nishitani I- 12

Yuji Noguchi P- 8, P- 84

Yukio Noda P- 56

(O)

Haruka Okuda P- 64

J. -J. Oak P- 41, P- 42

Jeong-Hyeon Oh C- 5

M. Okuyama P- 11

Mayuko Ogawa P- 32

Minoru Osada I- 2

P. V. Ong P- 89

S. H. Oh C- 2

Takafumi Okamoto P- 32

Takeshi Oguchi P- 8

(P)

Baeho Park P- 50

Bong Chan Park P- 61

Cheolmin Park I- 4

Dhananjai Pandey P- 31

Dong-Soo Park P- 62

Hyunjun Park P- 67

J. S. Park P- 14

Je-Geun Park P- 45

Jin Su Park P- 15, P- 58, P- 79, P- 80

Jong Kyu Park P- 1

Jung Min Park P- 11

Min Hyuk Park C- 4, P- 7, P- 13

S. Park P- 68

Sang-Joon Park P- 4

Se-Jeong Park I- 3

Tae Gone Park P- 1

Youn Jung Park I- 4

(R)

C. M. Raghavan P- 41, P- 42

G. H. Ryu C- 7, P- 28, P- 59

Hyun Rhu P- 4

Jungho Ryu P- 40, P- 62

(S)

H. Shima P- 22

Hae Jin Seog P- 2, P- 37

Hiroyuki Sakurai I- 9

Hyun-A Song I- 11

James F. Scott P- 12

Ji Won Seo I- 13

Jong Yeog Son P- 51

Kengo Shibata P- 82

Kohei Suzuki P- 34

Kouhei Suzuki P- 69

M. Sohgawa P- 11

Masaru Shimizu P- 38, P- 39, P- 48,

P- 49

Muneyasu Suzuki I- 20

R. H. Shin C- 2, P- 43

Rebecca J. Sichel I- 14

Rikiya Sano I- 17

Shota Seto P- 48

Sung Min Seo P- 19

T. K. Song C- 7, P- 14, P- 28, P- 41,

P- 42, P- 59, P- 66

Tae Kwan Song P- 15, P- 16, P- 44,

P- 58, P- 79, P- 80

Takahisa Shiraishi I- 7

Takayoshi Sasaki I- 2

Takeshi Sakashita I- 10

Tatsuya Shimoda I- 5

Terutoshi Sakakura P- 56

Tomohiko Shibata P- 54

Y.-S. Seo P- 43

Yeon Soo Sung P- 44

Yeong Jae Shin P- 10

Yoshio Satoh I- 10

Young Jae Shin I- 6, P- 12

Young-Han Shin P- 51, P- 85, P- 86,

P- 87

Yukio Sato I- 18

(T)

Haruki Takayama P- 54, P- 69

Hiroki Taniguchi I- 15

Hiroyuki Tanaka I- 12

Kazuaki Taji P- 31

Kazuki Tanaka P- 30

Kenji Tsuda I- 17

Kohei Tsuchida P- 9

Masaki Takesada P- 53

Michiyoshi Tanaka I- 17

Naoki Toyota P- 52

Shinji Taniguchi I- 10

Shinya Tsukada P- 72, P- 83

Shoichi Takeda P- 33

Shuki Torii P- 84

Y. Togawa P- 46

Yoshinori Tokura P- 56

Yuhji Tsujimi P- 29

Yusuke Takada P- 48


(U)

Aman Ullah P- 61

Amir Ullah P- 61

Hokuto Usami P- 70

K. Ujimoto P- 26

Masanori Ueda I- 10

Michihito Ueda I- 12

Yoshiaki Uesu PL-2

(V)

N. Viart C- 2

(W)

K. Wakazono P- 26

M. Watanabe P- 55

Satoshi Wada C- 3, P- 63, P- 74, P- 77

Sung Sik Won P- 2, P- 3

T. Wada P- 23

Takahiro Wada I- 9, P- 24, P- 82

Won Seok Woo P- 2, P- 3

Yeong Sung Wang P- 5

Zhong Lin Wang P- 6

(Y)

A. Yamashita P- 55

Byung Kil Yun P- 6

Byung Youn You P- 4

Chang-Ho Yoon P- 57

Chan-Ho Yang I- 1

Dong Jin Yoon P- 40

Hiroko Yokota P- 70

Hironori Yoshimura P- 77

Hyunsuk Yoon P- 67

Hyunung Yu P- 4

Il-Hyuk Yoo C- 4

Il-Hyuk Yu P- 13

Jong Gul Yoon P- 16

Jong-Gul Yoon I- 6, P- 10, P- 12, P- 19

K. Yakushi P- 55

K. Yamamoto P- 55

Ken Yanai P- 84

Kenta Yamashita P- 74, P- 77

S. Yamazoe P- 23

Sang Mo Yang I- 6, P- 10, P- 12, P- 16

Seiji Yamazoe I- 9, P- 24, P- 82

Seongtak Yoon P- 75

Soon-Gil Yoon I- 11

T. Yamamoto P- 22

T. Yoshimura P- 26

Tae-Sik Yoon I- 19

Takeshi Yoshimura P- 25

Tomori Yanagisawa P- 29

Toshirou Yagi P- 53

Tsuyoshi Yokoyama I- 10

Woo Seok Yang P- 5

Yoshiki Yachi P- 25

Yu Yamamoto P- 24

Zuo-Guang Ye I- 16, P- 69, P- 72

(Z)

A. Zaman P- 66

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