(Invited) High-Temperature-Operating Dielectrics of Perovskite Oxides

Abstract

Perovskite oxides solid solutions of ferroelectric Bi0.5Na0.5TiO3 and hypothetical compound of Ba(Mg1/3Nb2/3)O3, namely (1-x)Bi0.5Na0.5TiO3-xBa(Mg1/3Nb2/3)O3 [(1-x)BNT-xBMN], were synthesized and their crystal structures were analyzed by neutron powder diffraction Rietveld analysis. Structural analysis shows that (1-x)BNT-xBMN constitutes two-phase mixture region composed of rhombohedral R3c and cubic Pm-3m in its phase diagram. Measurements of dielectric, ferroelectric polarization, and electric-field-induced strain properties indicate that (1-x)BNT-xBMN exhibits ferroelectric and piezoelectric properties for x < 0.04 while paraelectric properties for x > 0.05. Dielectric permittivity of (1-x)BNT-xBMN ceramics with x = 0.05 was an extremely high value of 2000-3000 in the high temperature range of 200-400 °C.