Engineering the nature of polarization dynamics in lead-free relaxors based on (Bi_1/2Na_1/2)TiO₃

(Bi1/2Na1/2)TiO3 (BNT) is a lead-free ferroelectric material, which has shown promising electromechanical properties and energy storage capacities. These attractive functionalities property performances are attributed to the relaxor behavior of BNT. However, nature dielectric relaxation not well understood in these materials, physical meaning some important parameters associated with permittivity still under debate. In this Letter, we focus on “shoulder,” Ts, that readily seen ε′–T curve every BNT-based relaxor. It found Ts controlled by only typical compositional engineering but also thermal, electrical, or mechanical history. From moderate temperature (≤250 °C), sample can be rapidly cooled room slowly an electrical bias form compressive stress. All three treatments lead nearly identical effect, alter respect rest remains unperturbed. Therefore, internal stress identified general perturbance polarization dynamics. Finally, “breathing” model revisited interpret for BNT materials metastable conditions.