Modeling of dielectric hysteresis loops in ferroelectric semiconductors with charged defects

TL;DR

This paper develops a phenomenological model to describe dielectric hysteresis loops in ferroelectric semiconductors with charged defects, explaining experimental observations like coercive fields and loop shapes.

Contribution

It introduces a modified Landau-Ginsburg approach with three coupled equations to model inhomogeneous ferroelectric semiconductors with charged defects.

Findings

Successfully reproduces coercive field values below thermodynamic limits

Explains various hysteresis loop shapes such as constricted and double loops

Quantitatively matches experimental data on thick PZT films

Abstract

We have proposed the phenomenological description of dielectric hysteresis loops in ferroelectric semiconductors with charged defects and prevailing extrinsic conductivity. Exactly we have modified Landau-Ginsburg approach and shown that the macroscopic state of the aforementioned inhomogeneous system can be described by three coupled equations for three order parameters. Both the experimentally observed coercive field values well below the thermodynamic one and the various hysteresis loop deformations (constricted and double loops) have been obtained in the framework of our model. The obtained results quantitatively explain the ferroelectric switching in such ferroelectric materials as thick PZT films.