High-temperature dielectric and relaxation behavior of Yb-doped Bi0.5Na0.5TiO3 ceramics

Microstructure, phase transition and dielectric properties of Yb-doped Bi0.5Na0.5TiO3 (BNT) ceramics were investigated. It is found that ytterbium promotes the grain growth and densification of the ceramics while Ti rich impurity appears due to the compensation of Ti-vacancy. The dielectric operational temperature range of the ceramics with a 15% tolerance was greatly broaden until 500 degrees C by ytterbium doping. Meanwhile, the diffuseness of the diffuse phase transition increases with the increase of doping Yb. BNT ceramics with 3 mol% Yb doping shows a near-plateau dielectric behavior in a broad temperature range from 147 to 528 degrees C and a low dielectric loss ( < 0.025) from 154 to 356 degrees C, indicating that it is a promising material for applications in high temperature capacitor.