A5082455990- Ferroelectric and Piezoelectric Materials
- Magnetic and transport properties of perovskites and related materials
- Microwave Dielectric Ceramics Synthesis
- Multiferroics and related materials
- Advanced Condensed Matter Physics
- Advanced Battery Materials and Technologies
- Crystal Structures and Properties
- Electronic and Structural Properties of Oxides
- High-pressure geophysics and materials
- Advancements in Battery Materials
- Thermal Expansion and Ionic Conductivity
- Physics of Superconductivity and Magnetism
- Inorganic Fluorides and Related Compounds
- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- X-ray Diffraction in Crystallography
- Luminescence Properties of Advanced Materials
- Advancements in Solid Oxide Fuel Cells
- Acoustic Wave Resonator Technologies
- Crystallization and Solubility Studies
- Inorganic Chemistry and Materials
- Advanced Photocatalysis Techniques
- Transition Metal Oxide Nanomaterials
- Chemical Synthesis and Characterization
- Layered Double Hydroxides Synthesis and Applications
Gakushuin University
2015-2024
Tokai University
2012-2014
National Institute for Materials Science
2009
Tokyo Institute of Technology
1993-2005
Le Mans Université
2004-2005
Centre National de la Recherche Scientifique
2004-2005
Mejiro University
2004
Universidad Carlos III de Madrid
2003
Institut Laue-Langevin
2003
Kyung Hee University
1998
Ferroelectricity was induced in $\mathrm{SrTiO}{}_{3}$ by the isotope exchange of ${}^{18}\mathrm{O}$ for ${}^{16}\mathrm{O}$. Dielectric measurements confirmed ferroelectricity $\mathrm{SrTi}{}^{18}\mathrm{O}{}_{3}$, showing a peak at 23 K. A hysteresis loop $D$ vs $E$ measurement and TO phonon observed Raman spectra supported evolution $\mathrm{SrTi}{}^{18}\mathrm{O}{}_{3}$. This is first demonstration $\mathrm{SrTi}\mathrm{O}{}_{3}$ becoming ferroelectric without application external...
A polar oxide ZnSnO3 was synthesized by a solid-state reaction under pressure of 7 GPa and temperature 1000 °C. The crystal structure determined Rietveld analysis the X-ray powder diffraction data. has rhombohedral LiNbO3-type with unit cell parameters, = 0.52622(1) nm, c 1.40026(2) nm (space group: R3c). is characterized large displacement Zn along c-axis in ZnO6 octahedron based on strong chemical bonding between three O. candidate piezoelectric pyroelectric material as well nonlinear...
We report the results of a neutron powder diffraction study La(0.62)Li(0.16)TiO3 perovskite that determined diffusion path lithium cations at room temperature. At 77 K, Li are located 2c site (Wycoff notation Cmmm space group) on (002) La deficient layer, while, temperature, they spread over wide area and migrate following 2c-4f-2c or 2c-2d-2c tie line layer. The probability density has minimum between 4f 2d positions in contrast to previous reports where bottleneck been thought be 2c, 2d,...
The microwave dielectric characteristics of ilmenite titanates, M 2+ TiO 3 (where =Ni, Mg and Mn) ( 0.95 0.05 )TiO = Ni, Mg, Co series, have been investigated as a function ionic radius (Mg ) ions, respectively. titanates high Q value low constant due to the isolation 6 octahedra by O octahedron layer cation vacancy in comparison with perovskite titanates. existence localized d electrons Ni (3 8 Mn 5 is concerned properties series. ε r at 10 GHz series shows minimum around average 0.721 Å,...
Abstract We report that the orthorhombic–rhombohedral phase transition temperature in sodium potassium niobate could be tuned from lower to higher than room by incorporating barium zirconate into it. It is revealed when between 8 mol% and 15 mol%, solid solution exhibits rhombohedral symmetry at temperature. Rietveld analysis shows space group of R3m. suggested a relatively larger B‐cation favors low‐temperature which common phenomenon for perovskite ferroelectrics. (© 2009 WILEY‐VCH Verlag...
A polar LiNbO3-type (LN-type) titanate ZnTiO3 has been successfully synthesized using ilmenite-type (IL-type) under high pressure and temperature. The first principles calculation indicates that LN-type is a metastable phase obtained by the transformation in decompression process from perovskite-type phase, which stable at Rietveld structural refinement synchrotron powder X-ray diffraction data reveals crystallizes into hexagonal structure with space group R3c exhibits greater...
We synthesized two high-pressure polymorphs PbNiO(3) with different structures, a perovskite-type and LiNbO(3)-type structure, investigated their formation behavior, detailed structural transformation, thermal stability, valence state of cations, magnetic electronic properties. A at 800 °C under pressure 3 GPa crystallizes as an orthorhombic GdFeO(3)-type structure space group Pnma. The reaction high was monitored by in situ energy dispersive X-ray diffraction experiment, which revealed that...
Perovskite thin-film electroluminescence devices are prepared, opening up a new optical application of perovskite materials. With increasing driving voltage, the intensity increases dramatically. High-quality red color is produced and working voltage for whole-surface as low 10 V.
We successfully synthesized a novel ferroelectric A-site-ordered double perovskite CaMnTi2O6 under high-pressure and investigated its structure, ferroelectric, magnetic dielectric properties, high-temperature phase transition behavior. Optical second harmonic generation signal, by frequency doubling 1064 nm radiation to 532 nm, was observed efficiency is about 9 times as much that of SiO2 (α-quartz). This compound possesses tetragonal polar structure with space group P42mc. P-E hysteresis...
LiNbO(3)-type MnMO(3) (M = Ti, Sn) were synthesized under high pressure and temperature; their structures magnetic, dielectric, thermal properties investigated; relationships discussed. Optical second harmonic generation synchrotron powder X-ray diffraction measurements revealed that both of the compounds possess a polar structure at room temperature. Weak ferromagnetism due to canted antiferromagnetic interaction was observed 25 50 K for MnTiO(3) MnSnO(3), respectively. Anomalies in...
A lead-free ferroelectric: The occurrence of ferroelectricity is demonstrated in a silicate-based compound (Bi2SiO5, see picture), by direct observation polarization switching. mechanism Bi2SiO5 has been studied Raman scattering, transmission electron microscopy, X-ray powder diffraction, and first-principles calculations. observed stems from twisting the one-dimensional SiO4 tetrahedral chain. As service to our authors readers, this journal provides supporting information supplied authors....
Ion conductors comprising noncentrosymmetric frameworks have emerged as new functional materials. However, strongly correlated polarity functionality and ion transport not been achieved. Herein, we report a ferroelectric proton conductor, K2MnN(CN)4·H2O (1·H2O), exhibiting the strong correlation between its polar skeleton conductive ions that generate anomalous ferroelectricity via proton-bias phenomenon. The application of an electric field ±1 kV/cm (0.1 Hz) on 1·H2O at 298 K produced...
Stabilization of a perovskite-type solid solution (1−x) PbTiO3–x BiScO3 with x⩾0.45 was demonstrated by high-pressure synthesis, and the phase diagram ferroelectric properties were investigated. The crystal symmetry perovskite subcell change in turn from tetragonal, to rhombohedral, pseudocubic, monoclinic, then triclinic as x increases. It found that pseudocubic phases are ferroelectric, while monoclinic is not. In morphotropic boundary vicinity x=0.37 between tetragonal rhombohedral...
The ionic conductivity of the polycrystalline has been measured as a function hydrostatic pressure up to 1.2 GPa in temperature range between 238 and 294 K. decreased with an increase pressure. value activation volume for motion derived from data is positive almost invariable, , measured. This implies that dilatation lattice occurs during transport process. energy slightly increased mechanism conduction discussed on basis these results.