Redistribution of Random Nanoregions in Polarized Relaxor Ferroelectrics

The dielectric permittivity in Pb0.85La0.10Zr0.6Ti0.4O3 (PLZT 10/60/40) relaxor ferroelectrics is studied for different degrees of poling. We find that the half width of the dielectric permittivity and the transition temperature dependence on frequency becomes smaller by increasing the degree of poling. In order to explain such behavior we consider a model, previously used to study uniaxial relaxor ferroelectrics, where the nanoregions inside the sample are redistributed by applying an external electric field. The redistribution consists in a decrease on the dispersion of the random fields affecting to each nanoregion. This decrease on the dispersion decimates both, the broadening of the dielectric peak and the dependence with frequency of the transition temperature.