Tunable perpendicular exchange bias in oxide heterostructures

TL;DR

This paper demonstrates a tunable perpendicular exchange bias in oxide heterostructures, achieved through synthesis of La$_2$CuO$_4$ and (La,Sr)MnO$_3$, with control via doping levels, offering new avenues for magnetic device stability.

Contribution

It introduces a novel method to realize and control perpendicular exchange bias in oxide heterostructures using canted antiferromagnetic layers.

Findings

Strong perpendicular exchange bias observed in heterostructures.

Exchange bias magnitude controllable via doping levels.

Canted antiferromagnetism as a source of uniaxial anisotropy.

Abstract

The exchange bias effect is an essential component of magnetic memory and spintronic devices. Whereas recent research has shown that anisotropies perpendicular to the device plane provide superior stability against thermal noise, it has proven remarkably difficult to realize perpendicular exchange bias in thin-film structures. Here we demonstrate a strong perpendicular exchange bias effect in heterostructures of the quasi-two-dimensional canted antiferromagnet La$_2$CuO$_4$ and ferromagnetic (La,Sr)MnO$_3$ synthesized by ozone-assisted molecular beam epitaxy. The magnitude of this effect can be controlled via the doping level of the cuprate layers. Canted antiferromagnetism of layered oxides is thus a new and potentially powerful source of uniaxial anisotropy in magnetic devices.