Thickness dependence of dielectric nonlinearity of lead zirconate titanate films

The first-order reversal curves (FORC) distribution of PbZr_0.52Ti_0.48O₃ thin films was characterized as a function of film thickness. It was found that the thickness dependence of the small-field dielectric constant is due primarily to differences in the domain wall contributions to the properties. The irreversible FORC distribution decreased and the switching fields increased as the thickness decreased; this is compatible with reported Rayleigh analyses. The polarization-electric field data and the ac field dependence of the dielectric constant were modeled using the FORC distributions, and were found to give a good fit to the experimental results. Some discrepancies remain in the high-field dielectric constant, probably caused by its definition.