Ultra-slim electrostrains with superior temperature-stability in lead-free sodium niobate-based ferroelectric perovskite
Ruiyi Jing, Qingyuan Hu, Leiyang Zhang, Yuan Sun, Jiagang Wu, Denis Alikin, V. Ya. Shur, Xiaoyong Wei, Hongliang Du, Yunfei Chang, Li Jin
Abstract
Large electrostrains with high temperature stability and low hysteresis are essential for applications in high-precision actuator devices. However, achieving simultaneously all three of the aforementioned features in ferroelectric ceramics remains a considerable challenge. In this work, we firstly report a high unipolar electrostrain (0.12% at 60 kV/cm) in (1–x)NaNbO3-x[(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3] (NN-xBCZT) ferroelectric polycrystalline ceramics with excellent thermal stability (variation less than 10% in the temperature range of 30–160 °C) and ultra-low hysteresis (<6%). Secondly, the high-field electrostrain response is dominated by the intrinsic electrostrictive effect, which may account for more than 80% of the electrostrain. Furthermore, due to the thermal stability of the polarization in the pure tetragonal phase, the large electrostrain demonstrates extraordinarily high stability from room temperature to 140 °C. Finally, in-situ piezoelectric force microscopy reveals ultra-highly stable domain structures, which also guarantee the thermal stability of the electrostrain in (NN-xBCZT ferroelectrics ceramics. This study not only clarifies the origin of thermally stable electrostrain in NN-xBCZT ferroelectric perovskite in terms of electrostrictive effect, but also provides ideas for developing applicable ferroelectric ceramic materials used in actuator devices with excellent thermal stability.