Optimized strain property in Sm³⁺ doped 0.67BiFeO₃-0.33BaTiO₃ ceramics by electric field induced lattice distortion and domain wall motion

BiFeO₃-BaTiO₃ based ceramics with good piezoelectric properties and high Curie temperature are potential candidates for high temperature piezoelectric actuators. In this study, a high strain value of about 0.376 % and the low strain hysteresis of 13.3 % achieved in 0.67Bi_1-xSm_xFeO₃-0.33BaTiO₃ (0.1 ≤ x ≤ 2.0) ceramics. The contribution from the E-induced nanodomains and/or PNRs wall motion by fine-tuning Sm³⁺ contributes the increased strain; The contribution from the converse piezoelectric effect and the electrostrictive effect enhanced with the increase of x, due to the enlarged lattice shrinkage by replacing Sm³⁺ with small ionic radius and subsequent lattice distortion under high electric field. The strategy to simultaneously enhance the E-induced lattice distortion and nanodomains and/or PNRs wall motion of strain and balance their fractions to reduce the strain hysteresis may provide new insights to meet the practical applications of high-precision displacement actuators.