Polar domain walls trigger magnetoelectric coupling.

Josep Fontcuberta,Vladimir Laukhin,Xavier Granados,Ekhard K H Salje,Vassil Skumryev

doi:10.1038/srep13784

Abstract

Interface physics in oxides heterostructures is pivotal in material’s science. Domain walls (DWs) in ferroic systems are examples of naturally occurring interfaces, where order parameter of neighboring domains is modified and emerging properties may develop. Here we show that electric tuning of ferroelastic domain walls in SrTiO3 leads to dramatic changes of the magnetic domain structure of a neighboring magnetic layer (La1/2Sr1/2MnO3) epitaxially clamped on a SrTiO3 substrate. We show that the properties of the magnetic layer are intimately connected to the existence of polar regions at twin boundaries of SrTiO3, developing at , that can be electrically modulated. These findings illustrate that by exploiting the responsiveness of DWs nanoregions to external stimuli, even in absence of any domain contribution, prominent and adjustable macroscopic reactions of neighboring layers can be obtained. We conclude that polar DWs, known to exist in other materials, can be used to trigger tunable responses and may lead to new ways for the manipulation of interfacial emerging properties.

Highlights

By the continuity of the metal-oxygen coordination polyhedral network, the elastic coupling across interface transmits any structural transformation of the substrate into the overgrown thin film[18]
It has been shown that the magnetization of a La1−xSrxMnO3 (LSMO) thin film grown on STO(100) displays remarkable changes upon crossing TCT19–22, which were attributed to changes of the LSMO magnetic domain structure when shacked by the structural transition occurring in STO19–21
We shall demonstrate that STO can be used as “active” substrate to modify the magnetic properties of a LSMO epitaxial overlayer, namely the magnetic domain configuration, by exploiting its various low-temperature structural transformations and the presence of polar nanoregions at DWs

Summary

Introduction

By the continuity of the metal-oxygen coordination polyhedral network, the elastic coupling across interface transmits any structural transformation of the substrate into the overgrown thin film[18]. We shall demonstrate that STO can be used as “active” substrate to modify the magnetic properties of a LSMO epitaxial overlayer, namely the magnetic domain configuration, by exploiting its various low-temperature structural transformations and the presence of polar nanoregions at DWs. The results here presented constitute a fresh example of making use of the polar nature of domain walls in one layer to manipulate the magnetic domains in a neighboring layer. The results here presented constitute a fresh example of making use of the polar nature of domain walls in one layer to manipulate the magnetic domains in a neighboring layer This approach differs in its essence from the much investigated strain control - including through piezoelectric substrates - of the magnetic properties of LSMO and other oxides[23,24,25], where domains rather than DWs are the primarily responsive elements of the substrate. It will be shown that upon applying a suitable electric field to the STO substrate, an unparalleled response, and even a reversal of magnetic moment (m) of the LSMO layer can be obtained

Methods

Results

Conclusion