Dielectric properties, thermal decomposition and related aspects of BiAlO3

Abstract

BiAlO3, prepared under high-pressure and high-temperature conditions has a rhombohechal perovskite structure (R3c with a = 5.3747(4) angstrom and c = 13.391 (1) angstrom) and decomposes around 550 degrees C to form the intermediate Bi2Al4O9 phase along with the Bi26-xAlxO40-y and Al2O3. Above 580 degrees C, the intermediate phase changes into the Bi26-xAlxO40-y. Dielectric measurements show an anomaly at the decomposition temperature and hysteresis at room temperature with a maximum polarization of similar to 16 mu C/cm(2). Raman scattering measurements suggest softening of optical phonon modes, and are consistent with the occurrence of thermal decomposition of the rhombohedral phase to form the thermodynamically stable phase. (C) 2008 Elsevier Ltd. All rights reserved.