Constructing a magnetic handle for antiferromagnetic manganites

Abstract

Thin superlattices with 1:2 ratio of bulk antiferromagnetics SrMnO3 :RMnO3 (R=Lantanide) are known to exhibit ferrmagnetism due to electronic reconstruction. In this study the limited range of the charge transfer is used to generate thin ferromagnetic layers adjacent to A-type antiferromag- netic order in superlattices with thicker RMnO3 layers. The ferromagnetic layers strongly couple to the antiferromagnetic spins, which mediates coupling between neighboring antiferromagnets. Using a novel interference based neutron diffraction technique, we directly observed the relative orienta- tion of the antiferromagnetic layers and confirm the magnetic structure induced by this coupling using NdMnO3/SrMnO3 superlattices. Ferromagnetism in the thin interlayer regions was probed by polarized neutron reflectometry. Density functional theory calculations were applied to analyze the driving forces for the exchange in more detail. The calculations reveal a ferromagnetic coupling and charge transfer across the interface. These results constitute promising steps on a path towards magnetic control of antiferromagnetic arrangements as would be necessary in spin-based multiferroic devices with strong magnetoelectric coupling.