Enhanced electrical properties related to structural distortion of CaBi2Nb2O9-based piezoelectric ceramics

CaBi2Nb2O9 (CBN)-based high Curie temperature piezoelectric ceramics with formula Ca0.8-xSrx(Li0.5Ce0.15Bi0.35)(0.2)Bi2Nb1.94Ta0.04W0.02O9 were prepared by conventional solid-state reaction method. The effects of strontium substitution for calcium in CBN pseudo-perovskite structureA-site were systematically studied. Results showed that the addition of Sr2+ ions lead to an improvement of the tetragonality of lattice structure, which resulted in an enhancement of piezoelectric and ferroelectric properties together with high Curie temperature T-C and good resistance to thermal depolarization. The analysis of dielectric spectrums revealed that the space charge polarization induced an additional dielectric anomaly occurred below T-C. The composition with x=0.025 showed good integrated performance, the piezoelectric coefficient d(33) and T-C were 17.5pC/N and 917 degrees C, respectively. Even though the as-studied ceramics underwent high depolarizing temperature reached up to 875 degrees C, d(33) decreased by 8% merely. The remanent polarization 2P(r) and the resistivity at 650 degrees C were on the order of 10C/cm(2) and 3x10(5)cm, respectively.