Low-temperature dielectric anomaly in Bi0.5K0.5TiO3

Abstract

Here, we report our studies on Bi0.5K0.5TiO3 (BKT) prepared by conventional solid-state reaction method and two-step sintering method to further understand the dielectric dispersion around room temperature. The coexistence of the tetragonal and cubic phases is confirmed. Most importantly, we find an extra dielectric loss anomaly around –100 °C. The polarization response suggests the contribution of the hysteresis-free polarization. Correspondingly, a Raman-active mode around 75 cm−1 is frozen on cooling. A model is proposed to interpret the origin of the low-temperature dielectric anomaly.