Enhanced electrostrictive coefficient and suppressive hysteresis in lead-free ba_(1−x)sr_xtio₃ piezoelectric ceramics with high strain

Lead-free piezoelectric ceramics with both low hysteresis and superior electrostrictive coefficient features are crucial toward providing desired performance for intelligent electrical devices, especially in high-precision displacement actuators. In this work, we propose a novel scenario, which is to design the phase transition around ambient temperature to enhance electrostrictive effect and inhibit hysteresis. In other words, the dense ceramics with cubic phases (C) and tetragonal phases (T) coexisting at RT (room temperature) were designed. According to this scenario, the Ba_(1−x)Sr_xTiO₃ (abbreviated as BT-100xST) ceramics were fabricated by the conventional solid-state reaction method. The relaxor behavior, ferroelectric properties, crystal structure and microstructure of BT-100xST ceramics have been investigated in detail. As a result, the BT-100xST ceramics with x = 0.20–0.40 present relaxor behavior which was indicated by dielectric constant as a function of temperature and (polarization–electric field) P–E hysteresis loops. The BT-30ST ceramics exhibit enhanced electrostrictive coefficient Q₃₃ (>0.034 m⁴/C² ), and the electrostrictive strain and low hysteresis achieves 0.11% and 2%, respectively. The BT-100xST ceramics are considered as a prospective option for application in displacement actuators with high sensitivity and high precision.