Rotational hysteresis of the exchange anisotropy direction in Co/FeMn thin films

TL;DR

This study explores how rotating an external magnetic field affects the exchange anisotropy direction in Co/FeMn thin films, revealing hysteretic behavior influenced by FeMn layer thickness.

Contribution

It demonstrates the rotational hysteresis of exchange anisotropy in Co/FeMn thin films and links it to FeMn layer thickness and weak anisotropy effects.

Findings

Exchange anisotropy direction changes with applied field rotation.

Hysteretic behavior of the exchange field direction observed.

Hysteresis decreases as FeMn layer thickness increases.

Abstract

We have investigated the effects of rotating an applied field on the exchange anisotropy in Co/FeMn thin films. When the applied field is initially along the cooling field direction, the longitudinal hysteresis loop has a maximum coercivity and the transverse hysteresis loop is flat, indicating that the exchange field is along the cooling field direction. When the applied field angle is rotated away and then restored to the original field cooling direction, the exchange anisotropy direction has changed. The rotation of the exchange field direction trails the applied field and is hysteretic. The rotational hysteresis of the exchange field direction is due to the weak anisotropy in thin FeMn layers, and decreases with increasing FeMn thickness.