Element-specific Curie temperatures of Ni/Cu/Co trilayers

In order to improve our understanding of the magnetism of 3d-multilayers the following questions are of interest: How does a nonmagnetic cap or spacer layer, like Cu, influence the magnetism of 3d ferromagnetic films? How does the ferromagnetic order of one layer (i.e. Ni) influence another (i.e. Co) via a spacer? Using magnetic circular X-ray dichroism Co/Ni, Cu/Co and Cu/Ni bilayers and Co/Cu/Ni and Ni/Cu/Co trilayers grown on a Cu(0 0 1) substrate were investigated. After having been covered by 2-7 ML Cu, Ni and Co films exhibit a significantly lower T-c. For trilayers different Curie temperatures were determined for Ni and Co when separated by a 2-6 ML Cu spacer. The coupling of Ni and Co layers was found to be both ferromagnetic and antiferromagnetic, depending on the spacer thickness and the sequence of the layers. (C) 1998 Elsevier Science B.V. All rights reserved.