Faculty Profiles - TANIGUCHI Hiroki

Papers - TANIGUCHI Hiroki

Division display 281 - 300 of about 307 ／ All the affair displays >>

Ferroelectricity of SrTiO3 Induced by Oxygen Isotope Exchange

谷口博基

Structure and Bonding 124 page： 89 - 118 2007

その場観測ラマン散乱を用いた強誘電体ガラスの結晶化過程の研究

谷口博基

ニューガラス 84 page： 57 2007

Ferroelectricity of SrTiO<inf>3</inf> induced by oxygen isotope exchange Reviewed

Mitsuru Itoh, Hiroki Taniguchi

Structure and Bonding Vol. 124 page： 89 - 118 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER-VERLAG BERLIN

Typical quantum paraelectric SrTiO3 becomes quantum paraelectric by oxygen isotope exchange. Apparently the change in the Curie temperature Tc is explained by the criteria of the theory for quantum ferro/paraelectrics. Tc for an isotope-exchanged sample depends only on the average mass of oxygen. Ferroelectricity for the oxygen isotope-exchanged SrTiO3 results mainly from the condensation of the Slater-type soft mode. However, an order-disorder component exists in addition to the displacive soft mode component. Raman spectra and NMR results suggest that ferroelectric domains do not develop through the crystal-like normal ferroelectrics. The role of the lattice defect must be elucidated and related to the phase transition mechanism in future works. Oxygen isotope exchange is considered the best way to understand the phase transition mechanism of SrTiO3 because this exchange may not accompany the formation of random fields or defects. © Springer-Verlag Berlin Heidelberg 2007.

DOI： 10.1007/430_2006_046

Web of Science

Scopus

Precursory softening of polar mode in isotope-exchanged paraelectric strontium titanate studied by Raman scattering Reviewed

H. Taniguchi, M. Takesada, M. Itoh, T. Yagi

Ferroelectrics Vol. 337 page： 131 - 138 2006.8

Language：English Publishing type：Research paper (international conference proceedings)

Quantum paraelectric SrTiO 3 shows the ferroelectricity by the exchange of 16 O for its isotope 18 O. Raman scattering experiment is performed on the isotopically exchanged SrTi(O 0.32 16 18 O 0.68 ) 3 whose exchange rate is just below the critical exchange rate. Raman spectrum of ferroelectric soft mode in the paraelectric phase clearly indicates local symmetry-breaking induced by the 18 O-exchange. The temperature dependence of the soft mode in SrTi(O 0.32 16 18 O 0.68 ) 3 suggests the occurrence of local ferroelectric region before the onset of the ferroelectric phase. The inhomogeneity of the system induces the inhomogeneous softening of the soft mode in 18 O-exchanged SrTiO3.

DOI： 10.1080/00150190600738196

Web of Science

Scopus

Fabrication of BaTi<inf>2</inf>O<inf>5</inf> glass-ceramics with unusual dielectric properties during crystallization

Yu J.

Chemistry of Materials Vol. 18 ( 8 ) page： 2169 - 2173 2006.4

Crystal growth of 50mg-class single crystals of beta '-(BEDT-TTF)(2)ICl2 and crystal evaluation

Taniguchi H., Sato R., Satoh K., Kawamoto A., Okamoto H., Kobayasi T., Mizuno K.

JOURNAL OF LOW TEMPERATURE PHYSICS Vol. 142 ( 3-4 ) page： 437 - 440 2006.2

Raman scattering study of superionic conductor lithium tetraborate Li <inf>2</inf>B<inf>4</inf>O<inf>7</inf> Reviewed

Tatiana Dekola, Toshirou Yagi, Hiroki Taniguchi, Masaki Takesada, Ichiro Sekine

Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers Vol. 45 ( 1 A ) page： 152 - 154 2006.1

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

Raman scattering spectra of the superionic-conductive lithium tetraborate Li2B4O7 are observed in the frequency range between 0-1600cm-1 as a function of temperature from 4.2K to room temperature. The frequencies of four Raman active AI (TO) modes of 262, 353, 378, and 423 cm-1 at 4.2 K are newly assigned to be related closely with the motion of the Li-ions in superionic conduction. © 2006 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.45.152

Web of Science

Scopus

In Situ Raman Scattering Study on Successive Crystallization of Bulk BaTi2O5 Glass

Taniguchi Hiroki, Yu Jianding, Arai Yasutomo, Yagi Toshirou, Fu Desheng, Itoh Mitsuru

Abstract book of Russia/CIS/Baltic/Japan Symposium on Ferroelectricity Vol. 2006 ( 0 ) page： 42 - 42 2006

Conductive Boundary Layer in CaCu3Ti4O12 with Giant-Dielectric-Response

Fu Desheng, Arima Yosuke, Taniguchi Hiroki, Taniyama Tomoyasu, Itoh Mitsru, Yu Jianding, Koshihara Shin-ya

Abstract book of Russia/CIS/Baltic/Japan Symposium on Ferroelectricity Vol. 2006 ( 0 ) page： 80 - 80 2006

In Situ Raman Scattering Study on Crystallization of Bulk BaTi2O5 Glass

Taniguchi Hiroki, Yu Jianding, Arai Yasutomo, Yagi Toshirou, Fu Desheng, Itoh Mitsuru

Preprints of Annual Meeting of The Ceramic Society of Japan<br>Preprints of Fall Meeting of The Ceramic Society of Japan Vol. 2006 ( 0 ) page： 19 - 19 2006

Soft mode dynamics in O-18-exchanged SrTiO3 as inhomogeneous system Reviewed

Hiroki Taniguchi, Mitsuru Itoh, Masaki Takesada, Toshirou Yagi

TRANSACTIONS OF THE MATERIALS RESEARCH SOCIETY OF JAPAN, VOL 31, NO 1 Vol. 31 ( 1 ) page： 97 - 100 2006

Language：English Publishing type：Research paper (international conference proceedings) Publisher：ELSEVIER SCIENCE BV

Ferroelectric phase transition of quantum paraelectric SrTiO3 is induced by an exchange of O-16 for its isotope O-18 in a low temperature region. The dynamics of ferroelectric soft mode in weakly O-18-exchanged strontium titanate is studied by Raman scattering. A nominally Raman-inactive soft mode is observed in the paraelectric phase of SrTi((O0.32O0.68)-O-18-O-16)(3) due to the local symmetry-breaking. The observed soft mode spectrum shows the temperature dependence strongly affected by the inhomogeneity of the system. The soft mode nonuniformly freezes to induce the local ferroelectric order before the onset of ferroelectric phase. The dynamical inhomogeneity is concluded to play an essential role in the dielectric response of O-18-exchanged strontium titanate.

Web of Science

Ferroelectricity of SrTi18O3: Paradox in the Phase Transition Mechanism

Itoh Mitsuru, Taniguchi Hiroki

Abstract book of Russia/CIS/Baltic/Japan Symposium on Ferroelectricity Vol. 2006 ( 0 ) page： 3 - 3 2006

Isotope effect on the soft-mode dynamics of SrTiO3 studied by Raman scattering Reviewed

H. Taniguchi, T. Yagi, M. Takesada, M. Itoh

Physical Review B - Condensed Matter and Materials Physics Vol. 72 ( 6 ) 2005.8

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

The oxygen isotope effect on the soft-mode dynamics in quantum paraelectric SrTi (Ox18 O 1-x 16) 3 [STO18- x] is investigated by Raman scattering in terms of local symmetry breaking in the paraelectric phase. The exchange rates x of the O18 atoms are 0.23 [STO18-23] and 0.32 [STO18-32], which are less than the critical value xc (=0.33). In STO18-32, whose exchange rate is just below xc, the soft Eu mode shows hardening behavior in a low-temperature region indicating the onset of local ferroelectric order. On the other hand, the soft Eu mode in STO18-23 does not show any hardening behavior until 0 K. The enhancement of the inhomogeneity in the crystal by the exchange of O18 is concluded to play an essential role in the soft-mode dynamics of the quantum paraelectric and ferroelectric STO18- x. The relation between the soft-mode dynamics and quantum fluctuation is discussed. © 2005 The American Physical Society.

DOI： 10.1103/PhysRevB.72.064111

Web of Science

Scopus

Growth of ferroelectric micro-regions in SrTiO3 and SrTi((O0.23O0.77)-O-18-O-16)(3) studied by Raman scattering Reviewed

Taniguchi H, Yagi T, Takesada M, Itoh M

JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. 46 ( 1 ) page： 195 - 197 2005.1

19pYM-11 Raman Scattering Study of Superionic Conductor Lithium Tetraborate Li_2B_4O_7. Part II

Dekola Tatiana, Yagi Toshirou, Taniguchi Hiroki, Takesada Masaki, Sekine Ichiro

Meeting Abstracts of the Physical Society of Japan Vol. 60.2.4 ( 0 ) page： 803 2005

25pYR-2 Soft Mode and Precursory Lowing of Local Symmetry in Quantum Paraelectric STO18

Taniguchi H., Takesada M., Itoh M., Yagi T.

Meeting Abstracts of the Physical Society of Japan Vol. 60.1.4 ( 0 ) page： 913 2005

24aYR-7 Low-frequency modes in Li_2B_4O_7 crystals studied by Raman scattering

Dekola Tatiana, Taniguchi Hiroki, Takesada Masaki, Sekine Ichiro, Yagi Toshirou

Meeting Abstracts of the Physical Society of Japan Vol. 60.1.4 ( 0 ) page： 890 2005

Growth of Ferroelectric Micro-regions in SrTiO_3 and SrTi(^<18>O_<0.23>^<16>O_<0.77>)_3 Studied by Raman Scattering

谷口博基

Journal of the Korean Physical Society Vol.46 page： 195 - 197 2005

Effect of Oxygen Isotope Exchange on Ferroelectric Microregion in SrTiO3Studied by Raman Scattering

Taniguchi Hiroki, Takesada Masaki, Itoh Mitsuru, Yagi Toshirou

Journal of the Physical Society of Japan Vol. 73 ( 12 ) page： 3262 - 3265 2004.12

Effect of oxygen isotope exchange on ferroelectric microregion in SrTiO<inf>3</inf> studied by Raman scattering Reviewed

Hiroki Taniguchi, Masaki Takesada, Mitsuru Itoh, Toshirou Yagi

Journal of the Physical Society of Japan Vol. 73 ( 12 ) page： 3262 - 3265 2004.12

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

The ferroelectric microregion (FMR) in quantum paraelectric SrTiO 3 is studied by Raman scattering using an optical cryostat with a 3He refrigerator. By the partial exchange of the oxygen atom for its isotope 18O, broad FMR spectra change drastically to underdamped Lorentzian-type spectra with decreasing temperature below 10 K. The peak is assigned to the ferroelectric soft Eu mode. The intense and sharp spectra of the Eu mode, which are nominally Raman inactive, indicate that the symmetry is lowered to a non-centrosymmetric symmetry in FMR. Furthermore, the softening characteristic of the soft Eu mode in a low-temperature region implies that the symmetry is not necessarily ferroelectric. The local symmetry breaking is enhanced by the substitution of the isotope 18O. © 2004 The Physical Society of Japan.

DOI： 10.1143/JPSJ.73.3262

Web of Science

Scopus

　 PREV - NEXT 　

<TANIGUCHI Hiroki>

Papers - TANIGUCHI Hiroki