MAGNETIC COUPLING OF FE MO/FE AND CO/CU/CO SANDWICHES ACROSS WEDGED SPACER LAYERS/

Fe/Mo/Fe and Co/Cu/Co sandwiches were grown by molecular beam epitaxy onto Mo(100) and Cu(100) single crystals, respectively, and characteri zed by high- and low-energy electron diffraction and in situ surface m agneto-optic Kerr-effect measurements. The spacer layer in both case w as fabricated to have a wedged shape in order to create a continuous c hange of the spacer-layer thickness. Oscillatory behavior between ferr omagnetic and antiferromagnetic coupling was found; and is shown to or iginate at the interface between the magnetic layer and the spacer lay er. For Fe/Mo/Fe, short-period oscillations are observed with a period icity of approximately 3 ML of Mo. Hysteresis loops for antiferromagne tically coupled cases are calculated from a simple model, and the resu lts reproduce the general characteristics observed experimentally.