Dielectric Properties of Relaxor-based Ferroelectrics with Landau-Ginzburg-Devonshire Theory and Domain Effects*

Magnetoelectric coupling observed in relaxor-based ferroelectrics makes them attractive for a wide variety of sensing and information technology applications. We study the polarization dynamics and dielectric properties of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) thin films grown by RF sputter deposition. Using independent polarization and permittivity measurements, we analyze the permittivity as a function of the polarization, and compare to behavior extracted from Landau-Ginzburg-Devonshire theory in single and multiple domain models. We use this to determine the electric field and polarization ranges dominated by single and multiple domain effects, and investigate the electric field dependence of the permittivity, and the effect on magnetoelectric coupling. We also examine the effect of crystallographic orientation on the dielectric properties.