Domain wall roughness in epitaxial ferroelectric PbZr0.2Ti0.8O3 thin films

TL;DR

This study investigates the static and dynamic properties of ferroelectric domain walls in epitaxial PbZr0.2Ti0.8O3 thin films, revealing power-law roughness behavior and creep dynamics consistent with theoretical models of elastic interfaces.

Contribution

It provides experimental measurements of domain wall roughness and creep in ferroelectric thin films, confirming theoretical predictions for a 2.5-dimensional elastic interface with disorder.

Findings

Domain wall roughness follows a power law with exponent ~0.26 at short scales.

The dynamic exponent for domain wall creep is approximately 0.6.

Results align with theoretical models for a 2.5D elastic interface with disorder.

Abstract

The static configuration of ferroelectric domain walls was investigated using atomic force microscopy on epitaxial PbZr0.2Ti0.8O3 thin films. Measurements of domain wall roughness reveal a power law growth of the correlation function of relative displacements B(L) ~ L^(2zeta) with zeta ~ 0.26 at short length scales L, followed by an apparent saturation at large L. In the same films, the dynamic exponent mu was found to be ~ 0.6 from independent measurements of domain wall creep. These results give an effective domain wall dimensionality of d=2.5, in good agreement with theoretical calculations for a two-dimensional elastic interface in the presence of random-bond disorder and long range dipolar interactions.