Phase-field simulation of ferroelectric domain microstructure changes in BaTiO3

Abstract

Phase-field method has recently been extended and utilized across many fields of materials science. Since this method can systematically incorporate, the effect of coherency strain induced by lattice mismatch and applied stress as well as external electrical and magnetic fields, it has been applied to many material processes including solidification, solid-state phase transformations, and various types of complex microstructure changes. In this article, we focus on the ferroelectric domain microstructure changes followed by the structural phase transition from cubic to tetragonal phase in BaTiO3, and its morphological developments are simulated on the basis of the phase-field method. The circuit structure of polarization moments of ferroelectric domains including twin defects is simulated, and the domain morphology is controlled by both the electric dipole-dipole interaction among polarization moments and the elastic interaction among domains with different tetragonal distortion. The ferroelectric domain exchange induced by external electric field is also simulated, then the dielectric property, i.e., the polarization hysteresis curve, is calculated by integrating all the X components of polarization moment vector over the microstructure. Furthermore, the simulation of the reversible ferroelectric domain switching, which is a new phenomenon recently discovered by Ren, is also simulated as an advanced application of the present simulation model. © 2009 The Japan Institute of Metals.