Enhanced ferroelectricity of CaBi2Nb2O9-based high-temperature piezoceramics by pseudo-tetragonal distortion

(LiBi)-doped CaBi2Nb2O9 (CBN) ceramics were synthesized by the conventional solid-state sintering method. The effects of (LiBi) additives on the crystalline structure were explored by Rietveld refinements. The results showed that pseudo-tetragonal distortion was induced by (LiBi) additives when x >= 0.35. This structural distortion increased the spontaneous polarization along a-axis and decreased the quits spontaneous polarization along b-axis, which was beneficial to the polarization switching, thus promoting the ferroelectricity and decreasing the coercive field (E-C) of CBN based ceramics. The Ca-0.60(Li0.5Bi0.5)(0.40)Bi2Nb2O9 (CBNLB-40) ceramics possess the optimum ferroelectric property with 2P(r) of 10 mu C/cm(2) and a coercive field (E-C) lower than 100 kV/cm. Moreover, it exhibits a good ferroelectric fatigue-free property within 10(7) switched cycles. This work may provide a new method to promote the performance of Aurivillius ferroelectric-based non-volatile memory devices.