BNT-based ceramics with large strain and low hysteresis over a wide temperature range

The incompatibility between large electro-strain and low-strain hysteresis, in addition to the poor temperature stability of piezoelectric ceramics, limits the development of high-precision piezoelectric actuators. In this work, Bi_0.465Na_0.465Ba_0.07Ti_1−2xGa_xSb_xO₃ (abbreviated as BNBT7-xGS, x = 0, 0.01, 0.02, 0.03, 0.04, and 0.06) ceramics were designed. Specifically, when x = 0.02, the ceramics exhibit a critical state in the relaxor ferroelectric system with a typical relaxor P−E loop and an I−E curve of four peaks. At this composition, the room temperature strain is 0.4 %, which is capable of enhancing the electro-strain and reducing the hysteresis simultaneously. Furthermore, over the wide temperature range from 30 to 180°C, the minimum strain hysteresis (H_ys) is 7.13 %, and the maximum strain variation is only 16.8 %, demonstrating ultra-high temperature stability. This work introduces a model for addressing the dilemma between good electro-strain properties and insufficient temperature stability in lead-free piezoelectric ceramics, crucial for the development of modern high-precision actuators.