Strong strain dependence of ferroelectric coercivity in a BiFeO3 film

Abstract

The ferroelectric polarization loop of an epitaxial BiFeO3 film on a piezoelectric substrate has been investigated as a function of continuously and reversibly varied biaxial strain of ε=0.36%–0.51%. Over this range, the ferroelectric coercive field (EC) at 80 K increases reversibly by 36% with the increasing tensile strain. In contrast, phase-field simulations predict the opposite trend of dEC/dε<0. Therefore, we attribute the observed EC(ε) dependence to the strain dependence of domain dynamics, which are not included in thermodynamic models. The strain dependence of the remanent polarization agrees with previous results.