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

Landau-Devonshire-type phenomenological thermodynamic theory is employed to explain the electric field dependence of piezoelectric properties of tetragonal single domain PbZrxTi1-xO3 (PZT). The strong nonlinearity of the converse piezoelectric coefficient under a large external electric field is proved to be intrinsic both in bulk crystal and epitaxial tetragonal PZT thin films. The tunability of piezoelectric responses by an external electric field and its dependence on the film/substrate misfit and elastic compliance of thin films are characterized quantitatively. The theoretical predictions are in good agreement with the experimental results of piezoresponse scanning microscopy. Due to the large tunability of piezoresponse in it, PZT 50/50 (x=0.5) epitaxial film is a promising candidate for use in future tunable devices. (C) 2003 American Institute of Physics.