Probing the role of single defects on the thermodynamics of electric-field induced phase transitions

TL;DR

This paper investigates how individual defects influence the thermodynamics and kinetics of electric-field induced phase transitions in ferroelectric materials, using spatially-resolved imaging to analyze defect-domain interactions.

Contribution

It introduces a universal methodology for probing single defect effects on phase transition thermodynamics through combined spectroscopic and imaging techniques.

Findings

Single defect centers cause fine structures in hysteresis loops.

Defect size and built-in field are determined self-consistently.

Methodology applicable to various reversible bias-induced transitions.

Abstract

The kinetics and thermodynamics of first order transitions is universally controlled by defects that act as nucleation sites and pinning centers. Here we demonstrate that defect-domain interactions during polarization reversal processes in ferroelectric materials result in a pronounced fine structure in electromechanical hysteresis loops. Spatially-resolved imaging of a single defect center in multiferroic BiFeO3 thin film is achieved, and the defect size and built-in field are determined self-consistently from the single-point spectroscopic measurements and spatially-resolved images. This methodology is universal and can be applied to other reversible bias-induced transitions including electrochemical reactions.