Primitive exchange coupling in CoPt/MnN layered structures: Exchange coupling established during deposition

Abstract

Bilayer and trilayer films with ferromagnetic CoPt and antiferromagnetic MnN constituent layers have been prepared by facing-target magnetron sputtering with a 6 Oe magnetic field applied to an in-plane direction of the growing film. Primitive exchange coupling, which signifies the exchange coupling occurred without conventional field cooling, has been investigated systematically by varying the component layer thickness. It has been shown that the interfacial spin configuration that initiates exchange coupling can be established at the interface when the MnN layer grows on the surface of the CoPt layer under a small field. The primitive exchange coupling shows an increasing tendency with increasing the MnN layer thickness, and a decreasing tendency with increasing the coupled CoPt layer thickness. And the coercivity of the coupled CoPt layer remain almost unchanged within the whole thickness range of both MnN and CoPt, which suggests the coercivity of the coupled CoPt layer is not only affected by exchange coupling.