High thermal stability of electric field-induced strain in (1−x)(Bi_0.5Na_0.5)TiO₃-xBa_0.85Ca_0.15Ti_0.9Zr_0.1O₃ lead-free ferroelectrics

In ferroelectric materials high electric field-induced strain (EFIS) with good thermal stability is of much interest from both fundamental research and potential applications. Here we propose a strategy to achieve high thermally stable EFIS based on electrostrictive effect and thermal stability of polarization. According to this strategy, we synthesized (1−x)(Bi_0.5Na_0.5)TiO₃-xBa_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (BNT-xBCZT) ferroelectric ceramics in order to tailor the thermal stability of dielectric permittivity, polarization and EFIS. A dielectric platform with a wide temperature region is induced by increasing x from 0.24 to 0.36 gradually. From 30 °C to 150 °C, a variation of 20% polarization results in a change of 36% EFIS, suggesting a good thermal stability as expect. Temperature-insensitive electrostrictive coefficient Q₃₃ ranges from 0.0264 m⁴/C² to 0.0314 m⁴/C². These results not only prove the effectiveness of this strategy, but also suggest that this strategy can be applied to other ferroelectric materials to improve the thermal stability.