Unconventional Polarization Response in Titanite-Type Oxides due to Hashed Antiferroelectric Domains.

Domains in a crystal, which have crystallographic uniformity and are geometrically segmented, typically arise from various phase transitions. The physical properties within individual domains are inherently the same as those in the homogeneous bulk. As a result, sufficiently large domains have little influence on the bulk properties.

Synthesis of Pt-Loaded YWO:Eu Microspheres and Their Hydrogen-Sensitive Turn-Off Luminescence.

Pt nanoparticles were loaded on YWO:Eu phosphor microspheres to enhance hydrogen sensitivity at low temperatures through turn-off luminescence. Mesoporous YWO:Eu microspheres were synthesized first by a hydrothermal method. Pt loading on the surface of the YWO:Eu microspheres was then carried out by a method of the self-regulated reduction of surfactants using aqueous KPtCl solutions.

Biphasic Sol-Gel Synthesis of Microstructured/Nanostructured YVO:Eu Materials and Their HO Sensing Ability.

Microstructured/nanostructured YVO:Eu powders and films were synthesized through a biphasic sol-gel method, aiming at their application as HO sensing materials based on the turn-off luminescence of Eu ions. The synthesis was typically carried out at temperatures of 80 °C or lower by using organic solutions to dissolve vanadium alkoxide and aqueous solutions to dissolve yttrium and europium salts together with sodium carboxylates. The resultant crystalline YVO:Eu powders and films were characterized as containing micrometer-sized particles comprising primary nanoparticles with high specific surface areas.

Liquid-Phase Synthesis of Ba2V2O7 Phosphor Powders and Films Using Immiscible Biphasic Organic-Aqueous Systems.

A liquid-phase synthesis of inorganic phosphor materials at a moderate temperature was proposed by using immiscible liquid-liquid biphasic systems. A self-activated Ba2V2O7 phosphor was actually synthesized from vanadium alkoxide dissolved in an organic solution and barium acetate in an aqueous solution. A mild hydrolysis reaction of the alkoxide started at the organic-inorganic interface, and an intermediate compound, Ba(VO3)2·H2O, was initially formed.

Analysis of vibration waveforms of electromechanical response to determine piezoelectric and electrostrictive coefficients.

We developed a possible method to determine both coefficients of piezoelectricity (d) and electrostriction (M) at the same time by a waveform analysis of current and vibration velocity in the resonance state. The waveforms of the current and vibration velocity were theoretically described using the equations of motion and piezoelectric constitutive equations, considering the dissipation effect. The dissipation factor of the d coefficient and M coefficient is dielectric loss tangent tan δ.

Analysis of nonlinear transient responses of piezoelectric resonators.

The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient.