Local Probing of Mesoscopic Physics of Ferroelectric Domain Walls

TL;DR

This study investigates the complex polarization reversal behaviors near ferroelectric domain walls using localized electric fields, revealing the wall's significant influence on switching dynamics and linking macroscopic and mesoscopic physics.

Contribution

It provides experimental evidence of the rich polarization reversal behaviors near ferroelectric domain walls and analyzes the long-range effects using theory and modeling.

Findings

Wall is significantly softer than bulk in polarization switching.

Long-range influence of domain walls extends micrometers.

Correlated switching involves wall bending under sub-nucleation bias.

Abstract

Domain wall dynamics in ferroic materials underpins functionality of data storage and information technology devices. Using localized electric field of a scanning probe microscopy tip, we experimentally demonstrate a surprisingly rich range of polarization reversal behaviors in the vicinity of the initially flat 180\deg ferroelectric domain wall. The nucleation bias is found to increase by an order of magnitude from a 2D nucleus at the wall to 3D nucleus in the bulk. The wall is thus significantly ferroelectrically softer than the bulk. The wall profoundly affects switching on length scales of the order of micrometers. The mechanism of correlated switching is analyzed using analytical theory and phase-field modeling. The long-range effect is ascribed to wall bending under the influence of a tip bias well below the bulk nucleation field and placed many micrometers away from the wall. These studies provide an experimental link between the macroscopic and mesoscopic physics of domain walls and atomistic models of nucleation.