Strain engineering a multiferroic monodomain in thin-film BiFeO$_3$

TL;DR

This study demonstrates strain engineering in thin-film BiFeO$_3$ to achieve a monodomain state, enabling clearer insights into its multiferroic properties by controlling domain structures through substrate choice and exploiting magnetoelastic coupling.

Contribution

It introduces a method to grow monodomain BiFeO$_3$ films on specific substrates, revealing controlled magnetic and ferroelectric domain coupling for improved material understanding.

Findings

Successful growth of monodomain BiFeO$_3$ films on TbScO$_3$ substrates.

Magnetic polarity inversion upon ferroelectric switching.

Enhanced control over multiferroic domain structures.

Abstract

The presence of domains in ferroic materials can negatively affect their macroscopic properties and hence their usefulness in device applications. From an experimental perspective, measuring materials comprising multiple domains can complicate the interpretation of material properties and their underlying mechanisms. In general, BiFeO$_3$ films tend to grow with multiple magnetic domains and often contain multiple ferroelectric and ferroelastic domain variants. By growing (111)-oriented BiFeO$_3$ films on an orthorhombic TbScO$_3$ substrate, we are able to overcome this, and, by exploiting the magnetoelastic coupling between the magnetic and crystal structures, bias the growth of a given magnetic-, ferroelectric-, and structural-domain film. We further demonstrate the coupling of the magnetic structure to the ferroelectric polarisation by showing the magnetic polarity in this domain is inverted upon 180$^\circ$ ferroelectric switching