Aging of poled ferroelectric ceramics due to relaxation of random depolarization fields by space-charge accumulation near grain boundaries

TL;DR

This paper presents a theory explaining aging in poled ferroelectric ceramics through charge migration and space-charge accumulation near grain boundaries, aligning well with experimental data.

Contribution

It introduces a new theoretical model linking depolarization field relaxation to defect migration, explaining aging phenomena in ferroelectric ceramics.

Findings

The theory matches experimental aging data for Fe-doped lead zirconate titanate.

Charge migration driven by oxygen vacancies explains internal bias field development.

The model predicts aging behavior based on acceptor doping levels.

Abstract

Migration of charged point defects triggered by the local random depolarization field is shown to plausibly explain aging of poled ferroelectric ceramics providing reasonable time and acceptor concentration dependences of the emerging internal bias field. The theory is based on the evaluation of the energy of the local depolarization field caused by mismatch of the polarizations of neighbor grains. The kinetics of charge migration assumes presence of mobile oxygen vacancies in the material due to the intentional or unintentional acceptor doping. Satisfactory agreement of the theory with experiment on the Fe-doped lead zirconate titanate is demonstrated.