High electrostrain with high Curie temperature in BiFeO3-BaTiO3-based ceramics

Here, we report a high unipolar electrostrain (0.45%) with a high Curie temperature (T-C = 410 degrees C) in lead-free (1-x)(0.67BiFeO(3)-0.33BaTiO(3))-xSr(0.8)La(0.1)square 0.1TiO2.95 (square represents the A-site vacancy) piezoceramics with x = 0.02. Sr0.8La0.1 square 0.1TiO2.95 was introduced to construct a relaxor ferroelectric state. The obtained unipolar strain was thermally stable, and the variation from room temperature to 100 degrees C was only 10%. Systematic electromechanical and Raman spectra measurements revealed a composition driven phase transition from classical ferroelectric to relaxor ferroelectric phases and distorted internal stress field. This work provides a novel strategy to obtain high electrostrain in high temperature piezoceramics. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.