Evidence for dielectric aging due to progressive 180 domain wall pinning in polydomain Pb(Zr0.45Ti0.55)O3 thin films

TL;DR

This study provides evidence that dielectric aging in polydomain Pb(Zr0.45Ti0.55)O3 thin films is driven by progressive pinning of 180° domain walls, using a thermodynamic model and analysis of nonlinear dielectric response over time.

Contribution

It introduces a thermodynamic model linking nonlinear permittivity to microstructural domain parameters and demonstrates a method to estimate pinning center concentration changes during aging.

Findings

Dielectric aging is controlled by 180° domain wall pinning.

Nonlinear permittivity analysis can estimate pinning center concentration.

The model correlates microstructure with dielectric response evolution.

Abstract

An evidence that the dielectric ageing in the polydomain Pb(Zr0.45Ti0.55)O3 thin films is controlled by progressive pinning of 180 domain walls is presented. To provide such a conclusion, we use a general method, which is based on the study of the time evolution of the nonlinear, but anhysteretic, dielectric response of the ferroelectric to a weak electric field. A thermodynamic model of the ferroelectric system where the dielectric response is controlled by bending movements of pinned 180 domain walls is developed. Within this model, the nonlinear permittivity of the ferroelectric is expressed as a function of the microstructural parameters of the domain pattern. It is shown that using the analysis of the time evolution of the nonlinear permittivity, it is possible to estimate changes in the concentration of the pinning centers that block the movements of the 180 domain walls during aging in polydomain perovskite ferroelectrics.