Abstract: The incompatibility between large electro-strain and low-strain hysteresis, in addition to the poor tem-perature stability of piezoelectric ceramics, limits the development of high-precision piezoelectric actu-ators. In this work, Bi0.465 Na0.465 Ba0.07 Ti1-2 x Gax Sbx O3 (abbreviated as BNBT7-x GS, 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 0.40 %, 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 ( Hys ) 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 ce-ramics, crucial for the development of modern high-precision actuators.

Key words: Lead-free ceramics, Strain hysteresis, Temperature stability, Domain engineering