A microscopic model for polarization fatigue in ferro-electric perovskites was presented. It was based upon dipolar defects which were formed by the combination of O vacancies with impurity metal ions. The binding energy of an O vacancy to a Pt impurity in this material was calculated to be about 2.9eV. The complex was strongly polar, was stabilized by electron capture, and pinned the polarization of the surrounding lattice.

Dipolar Defect Model for Fatigue in Ferroelectric Perovskites. S.Pöykkö, D.J.Chadi: Physical Review Letters, 1999, 83[6], 1231-4