Effect of cooling field on the antiferromagnetic interlayer coupling and exchange biasing in two antiferromagnetically coupled CoPt multilayers

Abstract

In this work, we have investigated the effect of cooling field on the antiferromagnetic interlayer coupling and exchange biasing in the [Pt (5 Å) Co (4 Å)] 4 NiO (11 Å) [Co (4 Å) Pt (5 Å)] 4 multilayer with perpendicular anisotropy. When the cooling field lies between the switching fields of the top and bottom CoPt multilayers at 400 K, it has been found that both the out-of-plane interlayer coupling and the interfacial exchange biasing fields depend strongly on the cooling field, which is closely related to the magnetic domain configurations in the CoPt multilayers and the NiO spacer at the cooling field. When the magnetic domains in the CoPt multilayers and the unstable magnetic domains in the NiO spacer are removed at the high enough cooling field at 400 K, both the out-of-plane interlayer coupling and the interfacial exchange biasing fields after cooling tend to be constant with little dependence on the cooling field. © 2007 American Institute of Physics.