Induced magnetization in La$_{0.7}$Sr$_{0.3}$MnO$_3$/BiFeO$_3$ superlattices

TL;DR

This study uses polarized neutron reflectometry and density functional theory to demonstrate and explain the induced magnetization in BiFeO$_3$ layers within LSMO/BFO superlattices at low temperature.

Contribution

It provides the first direct measurement of induced magnetization in BFO superlattices and offers a theoretical explanation based on the bandgap and exchange interactions.

Findings

Induced magnetization of 75±25 kA/m at 10 K in BFO layers.

Magnetization extends through several atomic layers of BFO.

Theoretical model explains the magnetization via exchange field and bandgap effects.

Abstract

Using polarized neutron reflectometry (PNR), we observe an induced magnetization of 75$\pm$ 25 kA/m at 10 K in a La$_{0.7}$Sr$_{0.3}$MnO$_3$ (LSMO)/BiFeO$_3$ superlattice extending from the interface through several atomic layers of the BiFeO$_3$ (BFO). The induced magnetization in BFO is explained by density functional theory, where the size of bandgap of BFO plays an important role. Considering a classical exchange field between the LSMO and BFO layers, we further show that magnetization is expected to extend throughout the BFO, which provides a theoretical explanation for the results of the neutron scattering experiment.