Induced four fold anisotropy and bias in compensated NiFe/FeMn double layers

TL;DR

This paper uses a vector spin model to demonstrate how frustrations in a multisublattice antiferromagnet like FeMn induce four-fold magnetic anisotropies and exchange bias effects in a coupled ferromagnetic layer, influenced by interface disorder and interlayer exchange.

Contribution

It introduces a model showing how frustrations in FeMn lead to four-fold anisotropies and exchange bias, highlighting the effects of interface disorder and exchange interactions.

Findings

Four-fold anisotropies can be induced by frustrations in FeMn.

Exchange bias depends sensitively on interlayer exchange and interface disorder.

A wide range of anisotropies can occur even in perfect crystalline structures.

Abstract

A vector spin model is used to show how frustrations within a multisublattice antiferromagnet such as FeMn can lead to four-fold magnetic anisotropies acting on an exchange coupled ferromagnetic film. Possibilities for the existence of exchange bias are examined and shown to exist for the case of weak chemical disorder at the interface in an otherwise perfect structure. A sensitive dependence on interlayer exchange is found for anisotropies acting on the ferromagnet through the exchange coupling, and we show that a wide range of anisotropies can appear even for a perfect crystalline structure with an ideally flat interface.