A phase-field model of relaxor ferroelectrics based on random field theory

TL;DR

This paper introduces a novel phase-field model for relaxor ferroelectrics incorporating random field theory, successfully capturing key relaxor behaviors and their dependence on disorder strength through finite element simulations.

Contribution

It is the first to develop a mechanically coupled phase-field model based on random field theory for relaxors, integrating thermodynamics and microforce concepts.

Findings

Model reproduces relaxor features like domain miniaturization and large piezoelectric response.

Random field strength significantly influences domain structure and hysteresis.

Simulation results align with experimental observations.

Abstract

A mechanically coupled phase-field model is proposed for the first time to simulate the peculiar behavior of relaxor ferroelectrics. Based on the random field theory for relaxors, local random fields are introduced to characterize the effect of chemical disorder. This generic model is developed from a thermodynamic framework and the microforce theory and is implemented by a nonlinear finite element method. Simulation results show that the model can reproduce relaxor features, such as domain miniaturization, small remnant polarization and large piezoelectric response. In particular, the influence of random field strength on these features are revealed. Simulation results on domain structure and hysteresis behavior are discussed and compared with related experimental results.