Hysteretic behavior of angular dependence of exchange bias in FeNi∕FeMn bilayers: A new signature

Abstract

As a new signature, the hysteretic behavior of angular dependence of exchange bias in FeNi∕FeMn bilayers is studied as function of the constituent layer thickness. When the FeMn layer is thin enough, there is no hysteretic behavior. When the FeMn layer thickness is increased, the hysteretic effect reaches a maximum sharply and then decreases slowly as the FeMn layer thickness is further increased. It is independent of the ferromagnet layer thickness. This new phenomenon implies a thermally driven evolution of the magnetic state in the antiferromagnet layer.