MAGNETIC COUPLING OF CO LAYERS THROUGH A CU SPACER LAYER

In this paper we present results of investigations of the magnetic cou pling of Co layers through a Cu spacer layer. These were obtained by e xamining Co/Cu/Co sandwich layers by Lorentz microscopy in the Fresnel and Foucault imaging mode. Ferromagnetic (F) and antiferromagnetic (A F) coupling of the magnetic Co layers can be found for different Cu sp acer layer thicknesses. For the F coupled sandwich layer twin walls ha ve been observed and the Co layers are only F coupled throughout the s pecimen. For the mainly AF coupled sandwich layer we observed a partia l F and AF coupling of the Co layers which can be explained by thickne ss fluctuations of the Cu interlayer. Although we have to expect thick ness fluctuations of the Co spacer layer in the F and the mainly AF co upled system, we only observe partial F and AF coupling for the mainly AF coupled system and not for the F coupled system. Therefore AF coup ling is much more sensitive to thickness fluctuations than F coupling.