Large magnetoelectric coupling in multiferroic oxide heterostructures assembled via epitaxial lift-off

TL;DR

This paper demonstrates a method to transfer epitaxial ferromagnetic films onto ferroelectric substrates, enabling large, non-volatile magnetization changes driven by ferroelectric switching, with potential for broad application in functional oxide heterostructures.

Contribution

The authors developed a novel transfer technique for epitaxial oxide films, allowing strain-free integration with ferroelectric substrates and enabling large magnetoelectric effects.

Findings

Large non-volatile magnetization changes observed

Magnetic domain rotations mediated by ferroelectric switching

Method applicable to various epitaxial oxide films

Abstract

The strain dependent functional properties of epitaxial transition metal oxide films can be significantly modified via substrate selection. However, large lattice mismatches preclude dislocation-free epitaxial growth on ferroelectric substrates, whose strain states are modified by applied electric fields. Here we overcome this mismatch problem by depositing an epitaxial film of ferromagnetic La0.7Sr0.3MnO3 on a single crystal substrate of well lattice matched SrTiO3 via a film of SrRuO3 that we subsequently dissolved, permitting the transfer of unstrained La0.7Sr0.3MnO3 to a ferroelectric substrate of 0.68Pb(Mg1/3Nb2/3)O3 0.32PbTiO3 in a different crystallographic orientation. Ferroelectric domain switching, and a concomitant ferroelectric phase transition, produced large non volatile changes of magnetization that were mediated by magnetic domain rotations at locations defined by the microstructure - as revealed via high resolution vector maps of magnetization constructed from photoemission electron microscopy data, with contrast from x-ray magnetic circular dichroism. In future, our method may be exploited to control functional properties in dislocation free epitaxial films of any composition.