Faculty Profiles - TANIGUCHI Hiroki

Papers - TANIGUCHI Hiroki

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Enhancement of quantum ferroelectricity in SrTi18O<inf>3</inf> thin film Reviewed

Yasuhiro Fujii, Yuki Maeda, Masao Katayama, Hiroki Taniguchi, Hiroshi Takashima, Mitsuru Itoh, Yuji Matsumoto

Applied Physics Express Vol. 4 ( 9 ) 2011.9

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We fabricated 18O-exchanged SrTi18O0.03x16O0.03(100-x) (STO18) thin films on SrTi 16O3(001) single-crystal substrates by pulsed laser deposition from a SrTi18O3 single-crystal target at various growth temperatures and 16O2 partial pressures. The diffusion of 16O from the substrate could be successfully suppressed by growing films under high 16O2 partial pressures, and a homogeneously 18O-exchanged STO18 thin film (x=60) was then obtained. The STO18 film became ferroelectric at a critical temperature higher than that expected from the corresponding STO18 bulk sample by ∼10 K, at which the Raman spectra suggested that the first-order transition occurred, different from the case of the STO18 bulk. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/APEX.4.091501

Web of Science

Scopus

First-principles calculations of lattice dynamics in CdTiO3 and CaTiO3: Phase stability and ferroelectricity Reviewed

Hiroki Moriwake, Akihide Kuwabara, Craig A. J. Fisher, Hiroki Taniguchi, Mitsuru Itoh, Isao Tanaka

PHYSICAL REVIEW B Vol. 84 ( 10 ) 2011.9

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER PHYSICAL SOC

First-principles calculations of various phases of CdTiO3 carried out with the aim of obtaining insights into the mechanism of the ferroelectric phase transition and the structure of the low-temperature ferroelectric phase are reported. The results indicate that the preferred symmetry of the low-temperature phase is Pna2(1), rather than P2(1)ma, corresponding to a small relative shift of the Ti and O ions in the paraelectric Pnma phase with the polarization axis parallel to the long axis. Calculated phonon dispersion curves show a distinct soft mode at the Gamma point of the Pnma phase, which vanishes in the Pna2(1) phase, confirming that the transition to the ferroelectric phase is of the soft-mode displacive type. Calculations of perovskite CaTiO3, which also has an orthorhombic Pnma structure at room temperature but, unlike CdTiO3, does not exhibit a ferroelectric phase transition down to 4.2 K, were also carried out to help characterize the factors controlling ferroelectric phase transitions in perovskite titanates.

DOI： 10.1103/PhysRevB.84.104114

Web of Science

Switching of the symmetry of magnetic anisotropy in Fe/BaTiO<inf>3</inf> heterostructures Reviewed

Y. Shirahata, T. Nozaki, G. Venkataiah, H. Taniguchi, M. Itoh, T. Taniyama

Applied Physics Letters Vol. 99 ( 2 ) page： 022501/1 - 3 2011.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Switching of the symmetry of magnetic anisotropy is clearly demonstrated in an epitaxial Fe layer on BaTiO3, in association with the interface lattice distortion occurred at the structural phase transition of BaTiO 3. The polar plot of the normalized remanent magnetization shows the fourfold symmetry with the magnetization easy axis along [100] of Fe at room temperature, while that at 230 K exhibits the twofold symmetry with the easy axis along [110]. Spatially resolved micro-Raman inspection corroborates the fact that the change in the magnetic symmetry arises from the magnetoelastic coupling at the interface. © 2011 American Institute of Physics.

DOI： 10.1063/1.3609237

Web of Science

Scopus

Other Link： http://orcid.org/0000-0003-3683-5416

Ferroelectricity and electromechanical coupling in (1 - X)AgNbO <inf>3</inf>-xNaNbO<inf>3</inf> solid solutions Reviewed

Desheng Fu, Takahiro Arioka, Hiroki Taniguchi, Tomoyasu Taniyama, Mitsuru Itoh

Applied Physics Letters Vol. 99 ( 1 ) 2011.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

We observed the evolution of polarization states and electromechanical coupling in (1 - x) AgNbO3-xNaNbO3 solid solutions using dielectric and strain hysteresis loop techniques and show that the polarization evolves from the ferrielectric ordering in AgNbO3 to the ferroelectric ordering in NaNbO3. The crossover between these two states occurs in the solid solution with x ≈ 0.8. A strain level ≈ 0.20 is available in the ceramics of these solid solutions. Such a large electromechanical effect might be interesting for the development of piezoelectric materials. © 2011 American Institute of Physics.

DOI： 10.1063/1.3609234

Web of Science

Scopus

Understanding of the Relaxor Behaviors : Comprehensive Investigations from Polarization, Raman Scattering and Transmission Electron Microscopy Observations(Current Topics) Open Access

Fu Desheng, Taniguchi Hiroki, Itoh Mitsuru, Mori Shigeo

Butsuri Vol. 66 ( 4 ) page： 270 - 276 2011.4

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Physical Society of Japan

PMN relaxor is shown to be a nanosized ferroelectric from the polarization, lattice dynamics and transmission electron microscopic measurements. Its ferroelectric state broken in nanosized domains due to the quenched random field was clearly observed by aligning the domains along the same direction by a strong electric field for T<T_c〜225K. The reorientation of such nanosized domain is found to be essential for its giant dielectric response. In addition, a multiscale inhomogeneity of domain structure is found in the ferroelectric phase, in which many nanosized domains align together to form a single larger 'domain'.

DOI： 10.11316/butsuri.66.4_270

Open Access

CiNii Research

Raman scattering study of the soft mode in Pb(Mg<inf>1/3</inf>Nb <inf>2/3</inf>)O<inf>3</inf> Reviewed

Hiroki Taniguchi, Mitsuru Itoh, Desheng Fu

Journal of Raman Spectroscopy Vol. 42 ( 4 ) page： 706 - 714 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

Systematic Raman scattering experiments were performed on Pb(Mg 1/3Nb2/3)O3 (PMN) single crystals to resolve the low-wavenumber dynamics in the crystal. Careful checking of the angular dependence of the Raman spectra indicated that the intense peak around 45 cm-1, which always smears the low-wavenumber spectra, stems from the F2g mode due to Mg:Nb = 1:1 chemically ordered Fm3m region. A proper scattering configuration for eliminating the strong F2g mode allowed the observation of the lowest wavenumber soft mode dynamics in PMN. The results revealed the softening of the mode towards Tc with underdamped oscillation. The soft mode becomes overdamped in a wide temperature range above Tc, suggesting the development of cluster dynamics due to polar nanoregions. It recovers the underdamped oscillation and hardens in the high-temperature region. Finally, the physical picture of the relaxor phenomenon in PMN is discussed in terms of lattice dynamics by comparison with the typical displacive-type ferroelectric phase transition. A low-energy lattice dynamics in a typical relaxor ferroelectric material Pb(Mg1/3Nb 2/3)O3 (PMN) is investigated by Raman scattering spectroscopy. A rigorous optimization of Raman scattering configuration enables to detect a soft mode spectrum in PMN. Relaxor phenomenon is found to be triggered by the softening of the soft mode in an inhomogeneous system. Copyright © 2010 John Wiley & Sons, Ltd.

DOI： 10.1002/jrs.2746

Web of Science

Scopus

Spontaneous polarization estimation from the soft mode in strain-free epitaxial polar axis-oriented Pb(Zr,Ti)O<inf>3</inf> thick films with tetragonal symmetry Reviewed

Yoshitaka Ehara, Satoru Utsugi, Mitsumasa Nakajima, Tomoaki Yamada, Takashi Iijima, Hiroki Taniguchi, Mitsuru Itoh, Hiroshi Funakubo

Applied Physics Letters Vol. 98 ( 14 ) 2011.4

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

The ferroelectric property, crystal structure, and A1 (1TO) soft mode of almost strain-free epitaxial polar axis-oriented tetragonal lead zirconate titanate thick films grown on CaF2 substrates were investigated by changing the Zr/ (Zr+Ti) ratio and the temperature. The square of spontaneous polarization (Ps), Ps2, monotonically increased as tetragonal distortion, (c/a)-1, increased where a and c are the lattice parameters of the films and as the square of frequency in A1 (1TO), ω2 [A1 (1TO)], increased. Additionally, the relationships of Ps2, (c/a-1), and ω2 [A1 (1TO)] were experimentally obtained, which confirmed the P s value obtained from (c/a-1) and ω [A1 (1TO)] without direct polarization measurements. © 2011 American Institute of Physics.

DOI： 10.1063/1.3575565

Web of Science

Scopus

Ferroelectricity of Li-doped silver niobate (Ag, Li)NbO<inf>3</inf> Reviewed Open Access

Desheng Fu, Makoto Endo, Hiroki Taniguchi, Tomoyasu Taniyama, Mitsuru Itoh, Shin Ya Koshihara

Journal of Physics Condensed Matter Vol. 23 ( 7 ) page： 075901 2011.2

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

Phase evolution in (Ag1-xLix )NbO3 (ALN) solid solution was investigated by the x-ray diffraction technique, dielectric and polarization measurements. It is shown that a small substitution of Ag with Li gives rise to an orthorhombic-rhombohedral structural transformation in ABO3-perovskite silver niobate at room temperature. Structural refinements indicate that both the A- and B-site displacements contribute to the spontaneous polarization of the ferroelectric phase with symmetry R3c. Increasing Li-concentration enhances the ferroelectric rhombohedral distortion, resulting in an increase of the para-ferroelectric phase transition temperature and the polarization of the solid solutions. © 2011 IOP Publishing Ltd.

DOI： 10.1088/0953-8984/23/7/075901

Web of Science

Scopus

PubMed

Power-law quasielastic light scattering observed in relaxor Pb(Mg <inf>1/3</inf>Nb<inf>2/3</inf>)O<inf>3</inf> Reviewed

Akitoshi Koreeda, Seishiro Saikan, Hiroki Taniguchi, Mitsuru Itoh

Ferroelectrics Vol. 415 ( 1 ) page： 24 - 28 2011

Language：English Publishing type：Research paper (international conference proceedings) Publisher：TAYLOR & FRANCIS LTD

The low-frequency light-scattering spectrum in Pb(Mg1/3Nb 2/3)O3 single crystal is investigated at 297 K. A quasielastic scattering is found, and its line shape is identified as a "power-law" type, instead of a single Lorentzian or superposition of two Lorentzian curves. The power-law spectrum implies the existence of a wide distribution of relaxation times in relaxors. Copyright © Taylor &Francis Group, LLC.

DOI： 10.1080/00150193.2011.577365

Web of Science

Scopus

Properties of LiNbO3-type complex oxide thin films containing transition metal ions fabricated by the PLD technique

HAMASAKI YOSUKE, SHIMIZU TAKAO, TANIGUCHI HIROKI, TANIYAMA TOMOYASU, ITOH MITSURU

Preprints of Annual Meeting of The Ceramic Society of Japan Preprints of Fall Meeting of The Ceramic Society of Japan Vol. 2011 ( 0 ) page： 626 - 626 2011

Raman Scattering Study for a Ca-substitution effect on Ferroelectricity of CdTiO3

Taniguchi Hiroki, Hwee Ping Soon, Moriwake Hiroki, Shan Yue Jin, Itoh Mitsuru

Preprints of Annual Meeting of The Ceramic Society of Japan Preprints of Fall Meeting of The Ceramic Society of Japan Vol. 2011 ( 0 ) page： 320 - 320 2011

Domain Structure Analysis of BaTiO3 Thin Film on various SrTiO3 substrate

Shimizu Takao, Suwama Dai, Taniguchi Hiroki, Taniyama Tomoyasu, Itoh Mitsuru

Preprints of Annual Meeting of The Ceramic Society of Japan Preprints of Fall Meeting of The Ceramic Society of Japan Vol. 2011 ( 0 ) page： 286 - 286 2011

21pGN-5 Ca substitution effect on ferroelectricity of CdTiO_3 Open Access

Taniguchi Hiroki, Soon, Moriwake Hiroki, Shan Yue Jin, Shimizu Takao, Itoh Mitsuru

Meeting Abstracts of the Physical Society of Japan Vol. 66.2.4 ( 0 ) page： 974 2011

26aPS-122 Study on microstructures in (Ba, Ca)TiO_3 by transmission electron microscopy Open Access

Koyama Tsukasa, Ozaki Tomoatu, Mori Shigeo, Fu Desheng, SHimizu Takao, Taniguchi Hiroki, Itoh Mitsuru

Meeting Abstracts of the Physical Society of Japan Vol. 66.1.4 ( 0 ) page： 972 2011

26aPS-117 Polarized Raman spectra of ferroelectric oxide single crystals. Open Access

Fujii Y., Noju M., Nishio I., Shimizu T., Taniguchi H., Itoh M.

Meeting Abstracts of the Physical Society of Japan Vol. 66.1.4 ( 0 ) page： 970 2011

26aPS-113 Mechanism of structural phase transition in Ba_<1-x>Ca_xTiO_3 Open Access

SHIMIZU Takao, FU Desheng, TANIGUCHI Hiroki, TANIYAMA Tomoyasu, ITOH Mitsuru

Meeting Abstracts of the Physical Society of Japan Vol. 66.1.4 ( 0 ) page： 969 2011

26aPS-112 Synthesis and Physical Properties of K_2(NbO)_2Si_4O_<12> with Pseudo-one-dimensional Perovskite Chain Open Access

TANIGUCHI Hiroki, MORIWAKE Hiroki, ITOH Mitsuru

Meeting Abstracts of the Physical Society of Japan Vol. 66.1.4 ( 0 ) page： 969 2011

25pTM-3 Low-Frequency Light-Scattering Spectroscopy o Relaxor Pb(Mg_<1/3>Nb_<2/3>)O_3 (III) Open Access

Koreeda A., Saikan S., Taniguchi H., Itoh M., Mori S.

Meeting Abstracts of the Physical Society of Japan Vol. 66.1.4 ( 0 ) page： 960 2011

Ferroelectricity of Li-doped Silver Niobate (Ag,Li)NbO_3 Reviewed

谷口博基, 谷山智康

Journal of Physics : Condensed Matter Vol. 23 page： 0759011 - 7 2011

Spontaneous Polarization Estimation from the Soft Mode in Strain-Free Epitaxial Polar Axis-Oriented Pb(Zr, Ti)O_3 Thick Films with Tetragonal Symmetry Reviewed

谷口博基

Applied Physics Letters Vol. (in press) 2011

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Papers - TANIGUCHI Hiroki