Multi-step stochastic mechanism of polarization reversal in orthorhombic ferroelectrics

TL;DR

This paper presents a stochastic model for polarization reversal in orthorhombic ferroelectrics, capturing complex switching events and providing insights into the mechanisms underlying their electromechanical response.

Contribution

It introduces a comprehensive stochastic framework that describes all possible polarization switching paths, including non-180° events, in orthorhombic ferroelectrics.

Findings

Identified dominant polarization switching paths in (K,Na)NbO3 ceramics.

Quantified fractions and activation fields of different switching processes.

Revealed significant contributions of non-180° switching events.

Abstract

A stochastic model of electric field-driven polarization reversal in orthorhombic ferroelectrics is advanced, providing a description of their temporal electromechanical response. The theory accounts for all possible parallel and sequential switching events. Application of the model to the simultaneous measurements of polarization and strain kinetics in a lead-free orthorhombic (K,Na)NbO3-based ferroelectric ceramic over a wide timescale of 7 orders of magnitude allowed identification of preferable polarization switching paths, fractions of individual switching processes, and their activation fields. Particularly, the analysis revealed substantial contributions of coherent non-180{\deg} switching events, which do not cause macroscopic strain and thus mimic 180{\deg} switching processes.