Strong anti-ferromagnetic coupling in τMnAl/Co perpendicular magnetic superlattices on GaAs

This paper reports on the structural and magnetic properties of τMnAl/Co superlattices epitaxially grown on AlAs/GaAs by Molecular Beam Epitaxy. In τMnAl/Co superlattices with Co layer thickness <8 Å, a strong antiferromagnetic coupling between the ferromagnetic τMnAl and Co layers is found, as well as the presence of a large perpendicular magnetic anisotropy in both constituent layers, resulting in an unusually abrupt spin reversal at high fields. When increasing the Co layer thickness, the shape anisotropy in the Co layers dominates this AF coupling and the constituent layers display different magnetization directions: perpendicular (τMnAl) and parallel (Co) to the growth plane