LAUSR

Abstract In this work, the relationships between the composition-driven phase boundary, ferroelectricity and strain properties of the (1- x )(K 0.48 Na 0.52 )(Nb 1- y Sb y )O 3 - x Bi 0.5 (Na 0.82 K 0.18 ) 0.5 ZrO 3 (abbreviated as (1- x )KNN 1- y S y - x BNKZ) ceramics were investigated. A giant electric field-induced strain of 0.3% ( d 33 ∗  = 750 p.m./V) and a low hysteresis (16.4%) were obtained in the 0.97KNN 0.98 S 0.02 -0.03BNKZ ceramics. The giant strain is attributed to the enhanced piezoelectricity induced by the appearance of the O-T phase boundary and the electric-field-induced phase transition from the relaxor phase to the ferroelectric phase. Furthermore, the 0.97KNN 0.98 S 0.02 -0.03BNKZ ceramics exhibit good thermal stability in the temperature range from 25 °C to 150 °C. Hence, this work can promote the practical applications of KNN-based lead-free piezoelectric ceramics in highly sensitive and precise piezoelectric actuators.