Advancing piezoelectricity and excellent thermal stability: <001>-textured 0.75BF–0.25BT lead-free ceramics for high temperature applications

There is an urgent need for piezoelectric materials possessing both high piezoelectric properties and good thermal stability to facilitate the advancement of high temperature piezoelectric devices. However, conventional strategy for enhancing piezoelectricity via chemical modifications often comes at the cost of thermal stability due to a drop in Curie temperatures. In this study, we achieved remarkable results in <001>-oriented 0.75BiFeO₃–0.25BaTiO₃ (0.75BF–0.25BT) lead-free textured ceramics. These textured ceramics exhibit a high Curie temperatures T_c of 552 °C, large piezoelectric coefficients d₃₃ of 265 pC/N, and exceptional piezoelectric thermal stability, with minimal variation of 8% across temperature from 25 °C to 300 °C. Compared to randomly oriented ceramics, the piezoelectric coefficient is about 2.5 times higher, marking it as one of the highest reported value for ceramics with T_c near 550 °C. The enhanced piezoelectric properties can be ascribed to improvements in both intrinsic lattice distortions and extrinsic non-180^o domain motions, while the excellent piezoelectric thermal stability is attributed to the stable domain texture. These superior properties of the studied textured 0.75BF–0.25BT ceramics position them as competitive lead-free candidates for high-temperature piezoelectric applications.