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 m ethod is used to predict the electric displacement and strain of a pol ycrystalline ferroelectric ceramic under electromechanical load. The m odel 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 pred icted when axial stress and a fixed field are applied parallel to the polarization direction and either uniaxial stress or shear stress is a pplied perpendicular to the poled direction. Simulated electric displa cement versus electric field hysteresis loops and the corresponding st rain versus electric field butterfly loops are given with uniaxial str ess and shear stress applied perpendicular to the polarization of the poled ceramic.