Nonlinear electric field dependence of piezoresponse in epitaxial ferroelectric lead zirconate titanate thin films

Nonlinear electric field dependence of dielectric and piezoelectric properties of ferroelectric films was studied. A thermodynamic approach to describe the nonlinearity of piezoelectric response was used and quantitative characteristics of its tunability by the electric field both in bulk single crystals and in thin films was obtained. It was found that tunability is sensitive to misfit, and was possible to get different electric field tunabilities.