Simulation on dielectric susceptibility and domain evolution of relaxor ferroelectrics

Dielectric susceptibility and domain evolution of the relaxor ferroelectrics have been simulated using the Monte Carlo method upon the Potts-Ising model. The grain size effect and the applied ac field frequency effect on the dielectric susceptibility were theoretically investigated. We found that the dielectric susceptibility increases and the T_m (the temperature at which the dielectric susceptibility reaches the maximum) shifts to lower temperature with increasing average grain size or decreasing frequency. In addition, we obtained the value of the relaxation parameter γ estimated from the linear fit of the modified Curie-Weiss law; its changing trend with increasing average grain size or increasing frequency was well consistent with the experimental observation. From the results of the domain pattern evolution process, we observed the differences between relaxor ferroelectrics and normal ferroelectrics subjected to an applied ac field.