The role of magnetic anisotropy in spin filter junctions

TL;DR

This paper demonstrates that magnetic anisotropy at interfaces can be used to control transport behavior in oxide-based spin filter junctions, revealing new ways to tune spin filtering effects without nonmagnetic spacers.

Contribution

It introduces the use of magnetic anisotropy at interfaces to tune transport in oxide spin filter junctions, a novel approach compared to previous polycrystalline or spacer-based methods.

Findings

Magnetic anisotropy significantly influences transport behavior.

Abrupt changes in magnetic anisotropy suppress magnetoresistance.

Spin filtering observed without nonmagnetic spacer layers.

Abstract

We have fabricated oxide based spin filter junctions in which we demonstrate that magnetic anisotropy can be used to tune the transport behavior of spin filter junctions. Until recently, spin filters have been largely comprised of polycrystalline materials where the spin filter barrier layer and one of the electrodes are ferromagnetic. These spin filter junctions have relied on the weak magnetic coupling between one ferromagnetic electrode and a barrier layer or the insertion of a nonmagnetic insulating layer in between the spin filter barrier and electrode. We have demonstrated spin filtering behavior in La0.7Sr0.3MnO3/chromite/Fe3O4 junctions without nonmagnetic spacer layers where the interface anisotropy plays a significant role in determining transport behavior. Detailed studies of chemical and magnetic structure at the interfaces indicate that abrupt changes in magnetic anisotropy across the non-isostructural interface is the cause of the significant suppression of junction magnetoresistance in junctions with MnCr2O4 barrier layers.