Configuration-Dependent Interactions between Ferroelectric and Ferroelastic Domains in PZT Thin Films Revealed by In Situ TEM

Precise control of domain dynamics is fundamental to the performance of ferroelectric logic and memory devices. However, these dynamics are intrinsically coupled to the complex electromechanical landscape created by the coexisting ferroelastic domains. Using in situ transmission electron microscopy (TEM) and phase-field simulations, we investigate how moving ferroelectric domain walls interact with regular, tilted, and partial ferroelastic domain configurations in epitaxial PbZr 0.2 Ti 0.8 O 3 (PZT) thin films. We show that substrate-strain-mediated electromechanical coupling distorts selected ferroelastic walls away from charge-neutral geometries, creating localized charge centers and convergent internal electric fields. This configuration-dependent field landscape produces a dual response: ferroelastic domains can either accelerate switching through constructive field superposition or pin moving walls by inducing wall bending and electrostatic repulsion. These results establish a configuration-resolved framework for using ferroelastic microstructures to tune switching pathways and domain wall conductivity in ferroelectric oxide devices.