Pseudo‐Ferroelectric Domain‐Wall in Perovskite Ferroelectric Thin Films

Abstract

AbstractPerovskite ferroelectric thin films exhibit unique dielectric and piezoelectric properties owing to their internal polarized domains that accommodate the out‐of‐plane (ferroelectric) and in‐plane (ferroelastic) polarization‐induced electrostatic and elastic energy. These domains are generally treated as 2D defects with distinctive differences in domain morphology and domain‐wall characteristics, although they are indeed 3D volumetric defects. Here, by using atomistic simulation and microscopy characterization, a “pseudo‐ferroelectric domain” that has the morphology similar to a ferroelectric domain but holds the same defect character of ferroelastic domain‐wall, i.e., semi‐coherent (100)matrix||(100)domain interface is identified. Such pseudo‐ferroelectric domain walls will play a critical role in the migration kinetics of ferroelastic domains and in the piezoelectric responses of ferroelectric thin films during cyclic mechanical/electrical loading. The study throws light on a novel aspect of domains, namely, the 3D configuration and mobility of domain walls, and their role in the overall domain engineering.