Tuning the atomic and domain structure of epitaxial films of multiferroic BiFeO3

TL;DR

This paper investigates the atomic and domain structures of epitaxial BiFeO3 films, revealing mechanisms of domain formation and providing insights to control their properties for enhanced functionalities.

Contribution

It introduces a twining model explaining the prevalence of 71° domain walls in BiFeO3 films, linking atomic structure to domain formation under strain.

Findings

Identification of atomic and domain structures via advanced characterization.

Development of a twining model explaining domain wall types.

Insights into controlling film properties through structural tuning.

Abstract

Recent works have shown that the domain walls of room-temperature multiferroic BiFeO3 (BFO) thin films can display distinct and promising functionalities. It is thus important to understand the mechanisms underlying domain formation in these films. High-resolution x-ray diffraction and piezo-force microscopy, combined with first-principles simulations, have allowed us to characterize both the atomic and domain structure of BFO films grown under compressive strain on (001)-SrTiO3, as a function of thickness. We derive a twining model that describes the experimental observations and explains why the 71o domain walls are the ones commonly observed in these films. This understanding provides us with a new degree of freedom to control the structure and, thus, the properties of BiFeO3 thin films.