Dynamic response and roughening of ferroelectric domain walls driven at planar electrode edges

TL;DR

This study investigates how ferroelectric domain walls in thin films respond to electric fields at electrode edges, revealing their elastic nature and increasing roughness that could impact future ferroelectric memory devices.

Contribution

It demonstrates that ferroelectric domain walls behave as 1D elastic interfaces in disorder, with increasing roughness affecting device stability.

Findings

Domain walls are well described as 1D monoaffine elastic interfaces.

Roughness of domain walls increases as they move through disorder.

Roughening could limit the performance of ferroelectric racetrack memories.

Abstract

Understanding and controlling the motion, stability, and equilibrium configuration of ferroelectric domain walls is key for their integration into potential nanoelectronics applications, such as ferroelectric racetrack memories. Using piezoresponse force microscopy we analyse the growth and roughness of ferroelectric domains in epitaxial thin film Pb(Zr$_{0.2}$Ti$_{0.8}$)O$_3$, driven by the electric fields at straight edges of planar electrodes at two different temperatures. This device relevant geometry allows us to confirm that the domain walls are well described as 1-dimensional monoaffine elastic interfaces driven in random-bond disorder. However, we observe a progressive increase of roughness as initially flat domain walls move through the disorder landscape, which could prove a significant limiting factor for racetrack-type memories using ferroelectrics.