The prediction of switching in polycrystalline ferroelectric ceramics

A computer simulation for three dimensional polarization switching in a polycrystalline tetragonal ferroelectric ceramic is developed. The method is used to predict the electric displacement and strain of a polycrystalline ferroelectric ceramic under electromechanical load. The model is fitted to experimental strain versus electric field and strain versus stress curves of a ceramic lead lanthanum zirconate titanate (PLZT) at room temperature. Depolarizations of a poled ceramic are predicted when axial stress and a fixed field are applied parallel to the polarization direction and either uniaxial stress or shear stress is applied perpendicular to the poled direction. Simulated electric displacement versus electric field hysteresis loops and the corresponding strain versus electric field butterfly loops are given with uniaxial stress and shear stress applied perpendicular to the polarization of the poled ceramic.