Multiscaling analysis of ferroelectric domain wall roughness

TL;DR

This study investigates the roughness scaling behavior of ferroelectric domain walls in PZT thin films, revealing simple mono-affine scaling at small scales and complex multi-affine scaling at larger scales due to localized disorder variations.

Contribution

It provides the first multiscaling analysis of ferroelectric domain walls, highlighting the transition from mono-affine to multi-affine behavior and linking it to localized disorder effects.

Findings

Domain walls show mono-affine scaling up to 5 microns

Beyond 5 microns, walls exhibit multi-affine scaling

Localized disorder, possibly from dislocations, influences the multi-affine behavior

Abstract

Using multiscaling analysis, we compare the characteristic roughening of ferroelectric domain walls in PZT thin films with numerical simulations of weakly pinned one-dimensional interfaces. Although at length scales up to a length scale greater or equal to 5 microns the ferroelectric domain walls behave similarly to the numerical interfaces, showing a simple mono-affine scaling (with a well-defined roughness exponent), we demonstrate more complex scaling at higher length scales, making the walls globally multi-affine (varying roughness exponent at different observation length scales). The dominant contributions to this multi-affine scaling appear to be very localized variations in the disorder potential, possibly related to dislocation defects present in the substrate.