Impact of the Pyroelectric Effect on Ferroelectric Phase Transitions

The dependence of polarization on the temperature in ferroelectric bulk is investigated. In order to correctly predict the phase transition phenomena, we suggest to pass from the Landau-Ginzburg-Devonshire model to the Landau-Khalatnikov equation with simultaneous consideration of the pyroelectric effect. The developed approach allows us to derive an analytical expression describing the polarization behavior in the vicinity of the Curie point. Additionally, the analysis of obtained equations explains the temperature hysteresis with the difference of physical values at heating and cooling cycles. The model is verified by comparison between experimental data and theoretical results.