Phenomenological Theory of Polarization Reversal in Ferrielectric Bi4Ti3O12 Single Crystals

A theory describing polarization reversal in Bi4Ti3O12 single domain crystals based on observed time and field dependence of polarization P=f(E,t) is presented. The existence of a threshold switching field and a strong transverse dipole-dipole coupling is not only experimentally but also theoretically verified. The activation field α as well as mobility μ are related to the constants appearing in the basic equation. The theory gives time and field dependence of the switching current at constant temperature. Although the theory does not imply restriction on the applied field E(t), results are given only for pulsed and sinusoidal fields. Dependence of coercive field on applied field and frequency are presented. Switching resistance is calculated.