An intermediate metastable ferroelectric state induced giant functional responses in Bi0.5Na0.5TiO3 ceramics

Abstract

The local heterogeneities and phase transition in the ferroelectric Bi_0.5Na_0.5TiO₃ have a profound impact on the electrical properties. Herein, we have illustrated that the high functional properties involving domain switching and a heterogeneity dependent emerging phase transition are closely associated with intermediate local heterogeneity by comparing the as-prepared and field cycled BNT ceramics. A synergistic role can be triggered by the intermediate metastable ferroelectric state in view of this heterogeneity and associated phase transition with an applied electric field in the freshly prepared specimens. Multiple giant functional responses of colossal piezoelectricity, large electroresistance and dielectric tunability were achieved due to the significant increases in polarization orientations highly related to the metastable ferroelectric state of the localized structure. Particularly, record-setting piezoelectricity with d₃₃* = 17 816 pm V⁻¹ was obtained in the field-induced collaborative interaction. Discovering the catalytic effect of the intermediate metastable ferroelectric state will provide unique opportunities for the design of high-performance materials.