Improved strain and low hysteresis in (0.9-x)BaTiO₃-xCaTiO₃-0.1Ba(Zr_0.7Sn_0.3)O₃ lead-free relaxor ferroelectrics

For practical application of ceramics in high-sensitivity actuators, their performance must meet the requirements of both high strain and low hysteresis. Unfortunately, high strain in piezoelectric ceramics is usually accompanied by large hysteresis. Within this study, (0.9-x)BaTiO₃-xCaTiO₃-0.1(BaZr_0.7Sn_0.3)O₃ (BT-xCT-BZS) ceramics were prepared to solve this problem. A high piezoelectric constant (d₃₃) of 403 pC/N, and a large electric-field-induced strain (S_max) of 0.18% at 50 kV/cm with a low hysteresis (H_ys) of 6.2% were achieved simultaneously in the BT-0.14CT-BZS ceramic; this is mainly attributed to the existence of the orthorhombic-tetragonal (O-T) phase boundary of this relaxor ferroelectric and the formation of the microdomains observed in TEM images. These characteristics indicate that BT-CT-BZS-based ceramics are a prospective option for application in displacement actuators with high sensitivity and high precision.