Polarity and phase transition of a perovskite-type oxide Bi_1/2Ag_1/2TiO₃

Abstract

We synthesized a candidate ferroelectric oxide, Bi_1/2Ag_1/2TiO₃(BATO) under an oxygen pressure of about 1 MPa and investigated its structure and dielectric properties. According to a powder synchrotron X-ray diffraction and second harmonic generation (SHG) experiments, BATO is a polar perovskite-type oxide with an anti-phase tilt of TiO₆ octahedra. We also discuss the phase transition of BATO based on the results of high-temperature powder X-ray diffraction and the temperature dependences of dielectric permittivities and SHG intensity.