Local Structural Heterogeneity and Electromechanical Responses of Ferroelectrics: Learning from Relaxor Ferroelectrics

TLDR

Ferroelectric materials exhibit long‑range dipole ordering that forms reorientable domains, but relaxor ferroelectrics disrupt this order with cation disorder, creating nanoscale structural heterogeneity that underlies their exceptional dielectric, electro‑optic, and electromechanical properties yet whose origins remain poorly understood. The article introduces relaxor ferroelectrics’ complex polar states and their applications, then examines how local structural heterogeneity influences electromechanical performance and proposes strategies to harness this heterogeneity for enhanced device design. It discusses the link between nanoscale structural heterogeneity and electromechanical behavior, and outlines potential design strategies to exploit this heterogeneity to boost electromechanical performance. The article anticipates stimulating future research into the role of local structural heterogeneity for improving functional material properties.

Abstract

Abstract Long‐range ordering of dipoles is a key microscopic signature of ferroelectrics. These ordered dipoles form ferroelectric domains, which can be reoriented by electric fields. Relaxor ferroelectrics are a type of ferroelectric where the long‐range ordering of dipoles is disrupted by cation disorder, exhibiting complex polar states with a significant amount of local structural heterogeneity at the nanoscale. They are the materials of choice for numerous devices such as capacitors, nonlinear optical devices, and piezoelectric transducers, owing to their extraordinary dielectric, electro‐optic, and electromechanical properties. However, despite their extensive applications in these devices, the origins of their unique properties are yet to be fully understood, hindering the design and exploration of new relaxor ferroelectric‐based materials. Herein, the complex polar states and applications of relaxor ferroelectrics are first introduced. Attention is then focused on their electromechanical properties, where the relationship between local structural heterogeneity and the extraordinary electromechanical properties is discussed. Based on the understanding of relaxor ferroelectrics, potential strategies to exploit the local structural heterogeneity to design ferroelectrics for drastically enhancing their electromechanical performances are also discussed. It is expected that this article will stimulate future studies on the important roles of local structural heterogeneity in improving the properties of various functional materials.