JOPSS - Search Results

Journal Articles

Raman scattering study of the ferroelectric phase transition in BaTiO

Tsukada, Shinya*; Fujii, Yasuhiro*; Yoneda, Yasuhiro; Moriwake, Hiroki*; Konishi, Ayako*; Akishige, Yukikuni*

Physical Review B, 97(2), p.024116_1 - 024116_7, 2018/02

https://doi.org/10.1103/PhysRevB.97.024116

Times Cited Count：19 Percentile：65.6(Materials Science, Multidisciplinary)

Uniaxial ferroelectric BaTiO with a Curie temperature $T_{rm C}$ of 743 K was investigated to clarify its paraelectric-ferroelectric phase transition behavior. The mechanism is discussed on the basis of the structure from short to long ranges determined by synchrotron X-ray diffraction and the lattice dynamics probed by Raman spectroscopy. Using a combination of experimental results and first-principles calculations, we explain the phase transition. Ti vibration of TiO octahedral units is frozen in the ferroelectric phase and the space group changes from nonpolar to polar .

Journal Articles

Picosecond view of microscopic-scale polarization clusters in paraelectric BaTiO $_{3}$

Tai, R.; Namikawa, Kazumichi; Sawada, Akikatsu*; Kishimoto, Maki; Tanaka, Momoko; Lu, P.*; Nagashima, Keisuke; Maruyama, Hiroshi*; Ando, Masami*

Physical Review Letters, 93(8), p.087601_1 - 087601_4, 2004/08

A2004-0483.pdf:0.43MB

https://doi.org/10.1103/PhysRevLett.93.087601

Times Cited Count：76 Percentile：89.47(Physics, Multidisciplinary)

The polarization clusters existing in both the ferroelectric and the paraelectric phase of BaTiO $_{3}$ are directly observed and characterized for the first time by a picosecond soft X-ray laser speckle technique. These dynamic clusters appear continuously across the Curie temperature Tc. The clusters' distance increases approximately linearly with temperature, while their mean size does not change significantly. The polarization exhibits a maximum at a temperature about 5 degree above Tc. The clusters' short-range correlation strength diverges as (T-Tc)0.410.02 as temperature decreases toward Tc.

Journal Articles

Development of a full spatial coherent X-ray laser at 13.9 nm and its applications

Nagashima, Keisuke; Tanaka, Momoko; Nishikino, Masaharu; Kishimoto, Maki; Kado, Masataka; Kawachi, Tetsuya; Hasegawa, Noboru; Ochi, Yoshihiro; Sukegawa, Kota*; Tai, R.; et al.

Applied Physics B, 78(7), p.927 - 932, 2004/05

We have succeeded in developing a laser-pumped X-ray laser with full spatial coherence at 13.9 nm. A highly directed X-ray laser beam with the divergence of 0.2 mrad was generated from the double target experiment, where a seeding light from the first laser medium was amplified in the second medium. The observed divergence is close to the diffraction limit value within a factor of two. The seeding light was amplified in the second medium without refraction influence and the gain coefficient was about 8 cm-1. From the measurement of visibility, it was found that the spatial coherent length is longer than the beam diameter. As an application of this coherent X-ray laser, we observed a surface microstructure of ferroelectric material, BaTiO $_{3}$ and clarified a change of the microstructure near the Curie temperature.

Journal Articles

X-ray diffraction topography on a BaTiO crystal

Yoneda, Yasuhiro; Komura, Yoshiki*; Suzuki, Yoshio*; Hamazaki, Shinichi*; Takashige, Masaaki*

Journal of the Physical Society of Japan, 73(4), p.1050 - 1053, 2004/04

https://doi.org/10.1143/JPSJ.73.1050

We have observed 90 $^{circ}$ C domain walls in a bulk BaTiO crystal by Synchrotron radiation topography, coupled with a CCD detector. The BaTiO multi-domain crystal was revealed to be strained at the 90 $^{circ}$ C domain boundary. The polar direction of the BaTiO crystal was tilted by this starin, and this strain also causes the irregular angle of the surface bending mode. The Synchrotron X-ray topography can be performed on a sample with electrodes. The topographic image of the ferroelectric doamin with an electric field clarified that the well-known stripe domain configuration can not be observed without a weak electric field due to the lattice strain at the doamin boundary.