Magneto-optic Kerr effect at the interface of Co Gd bilayers

We have grown a set of crystalline Co/Gd(500 Angstrom) bilayers on glass su bstrates with a Cr buffer layer by magnetron sputtering. The interface betw een Co and Gd has been investigated by Auger spectroscopy depth profiles, v ibrating sample magnetometry (VSM) and magneto-optic Kerr effect (MOKE) on the air and glass sides of the sample at room temperature. The use of a Cr buffer with different thicknesses allowed us to probe the interface in MOKE measurements on the glass side. These show a small and reversed Kerr loop whereas those of the air interface are normal. Depth profiles indicate a wi de interface (similar to 3-4 nm thick) in the Cd side that is partly oxidiz ed. The results are discussed on the basis of polarization of interfacial s pins or the effect of the oxygen contamination. (C) 1999 Elsevier Science B .V. All rights reserved.