Remarkable Depolarization Resistance to High Electric Fields and High Temperatures in High-Power BS-PT Piezoelectric Ceramics

High-power, high-temperature piezoelectric ceramics are in high demand for efficient electromechanical energy transduction and conversion at elevated temperatures. To ensure the reliability of piezoelectric materials and devices, a large depolarization resistance is essential to withstand high electric fields and temperatures, which requires large coercive field E_C and high depolarization temperature T_d, respectively. In this study, the effects of Mn doping and tetragonality on the depolarization resistance and high-power performance of high temperature piezoelectric ceramics BiScO₃-PbTiO₃ (BS-PT) are investigated. The results demonstrate that the Mn-doped BS-PT ceramics exhibit an impressive depolarization temperature of 430 °C and a Curie temperature of 453 °C, with less than 5% degradation in the piezoelectric coefficient d₃₃ after annealing at 350 °C. Additionally, these ceramics show about three times higher E_C at high temperature (E_C = 9.5 kV cm⁻¹ at 300 °C), and higher vibration velocity (v = 0.86 m s⁻¹) and stable dielectric properties under high-drive conditions, when compared to PZT-5A ceramic counterparts. Theoretical analysis based on the Landau model, along with PFM and ferroelectric switching experiments, confirms that the large depolarization resistance and high stability are attributed to the formation of stable domain configurations via defect dipoles pinning effect and enhanced ferroelectric anisotropy.