Thermodynamics of Polydomain Ferroelectric Bilayers and Graded Multilayers

TL;DR

This paper develops a theoretical framework to understand the domain structures and polarization evolution in ferroelectric bilayers and graded multilayers, explaining their unique dielectric behaviors.

Contribution

It introduces a new theoretical model describing the equilibrium domain structures and polarization dynamics in graded ferroelectric multilayers.

Findings

Self-poled bilayer with single-domain and polydomain layers identified

Wedge-like domain movement explains polarization in graded multilayers

Theory accounts for peculiar dielectric behavior of graded ferroelectric films

Abstract

The equilibrium domain structure and its evolution under an electric field in ferroelectric bilayers and graded multilayers are considered. The equilibrium bilayer is self-poled and contains a single-domain and a polydomain (with 180 domains) layers. The polarization of a graded multilayer proceeds by movement of wedge-like domains as a result of progressive transformation of polydomain layers to a single-domain state. The theory provides the principal explanation of peculiarities of dielectric behavior of graded ferroelectric films and can be applied to graded ferromagnetics and ferroelastics.