Large electrostriction-like strain by tailoring relaxor degree in BNT-based ceramics

(Bi0.5Na0.5)TiO3-based relaxor ferroelectrics have attracted widespread attention due to huge electro-strain, but the existence of large hysteresis severely restricts their application. In this work, an effective strategy is developed to manipulate the direct proportional relation of the strain and hysteresis by tailoring relaxor degree via co-doping Sr2+ and Li+ at A-site in (Bi0.5Na0.5)TiO3 ceramic. It is shown that the relaxor composition Sr-0.35(Bi0.65Na0.62Li0.03)(0.5)TiO3 with medium relaxor degree demonstrates high strain of 0.25% simultaneously with ultra-low hysteresis of 5.1%, and the electrostrictive coefficient Q(33) is 0.022 m(4)/C-2 at room temperature. Moreover, the large strain and low hysteresis can maintain over a wide temperature range from 25 to 115 degrees C and frequencies ranges from 1 to 20 Hz. This study provides a new idea for designing high-performance Bi0.5Na0.5TiO3-based ceramic with high strain and low hysteresis.