Dipolar Defect Model for Fatigue in Ferroelectric Perovskites

Abstract

A microscopic model for polarization fatigue in ferroelectric perovskites based on dipolar defects formed by the combination of oxygen vacancies and impurity metal ions is presented. The binding energy of an oxygen vacancy to a Pt impurity in $\mathrm{PbTiO}{}_{3}$ is calculated to be $\ensuremath{\sim}2.9\mathrm{eV}$. The complex is strongly polar, is stabilized by electron capture, and pins the polarization of the surrounding lattice.