Correlation between depolarization temperature and lattice distortion in quenched (Bi1/2Na1/2)TiO3-based ceramics

Abstract

Abstract (Bi1/2Na1/2)TiO3 (BNT) is one of the candidates for lead-free piezoelectric ceramics. Recently, we found that the depolarization temperature T d of BNT could be increased by approximately 40 °C–80 °C with a quenching treatment after the sintering. To elucidate the mechanism, high-energy synchrotron X-ray powder diffraction data were collected in SPring-8 to analyze their crystal structures in detail. In the case of a quenched BNT-based sample, Bi ions displaced more to the off-center position of the A-site in a perovskite structure with a more ordered structure. The increase in rhombohedral distortion then affects the T d elevation in the quenched sample.