Modeling of the Hysteresis Behavior of Ferroelectroelastic Materials with Account of the Monoclinic Phase

Abstract

A microstructural model of the monoclinic M_A phase of a ferroelectroelastic material is proposed. The polarization direction occupies an intermediate position between the polarization directions of the tetragonal <001> and rhombohedral <111> phases. The fully coupled electromechanical microstructural model takes into account the multidomain structure, the dissipative domain wall motion, and the inhomogeneous distribution of mechanical stress fields and electric field strength in crystallites. The material response at the macrolevel is obtained by finite element homogenization of a representative volume element of polycrystalline piezoceramics. The proposed microstructural model allows to predict the extreme properties (high values of spontaneous polarization and spontaneous strain) of polycrystalline piezoceramics at the morphotropic phase boundary. Comparison of dielectric and electromechanical hysteresis curves demonstrated good prediction accuracy for experimentally observed curves for polycrystalline piezoelectric ceramics PZT PIC151.