Nonlinear electric field dependence of the transverse piezoelectric response in a (001) ferroelectric film

A non-linearly decreasing piezoelectric coefficient with an external electric field is an intrinsic property of a fully poled ferroelectric film, which has been observed in the measured longitudinal piezoelectric responses. However, for transverse piezoelectric responses, the observed converse piezoelectric coefficients (e(31),(f)) have displayed a different trend. Here we show that this disagreement can be rationally resolved by utilizing a small field e(3)(1,)(f) test under a sweeping direct current bias voltage, in which the field-dependent transverse piezoelectric response of a (001)-film is analyzed in a stepwise manner. Understanding of this nonlinear field-dependence will help improve the design of transverse piezoelectric devices. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.