Structure of Co/Cu multilayers studied by x-ray diffraction and x-ray absorption spectroscopy

Co/Cu (111) textured multilayers prepared in ultrahigh vacuum by thermal evaporation on a gold substrate have been characterized by x-ray diffraction, x-ray reflectivity, and x-ray absorption spectroscopy. The extended x-ray absorption fine-structure measurements show that in the plane of the layers, the Co lattice is slightly expanded and the Cu lattice is slightly contracted to compensate for the mismatch. The lattice strain is negligible in the growth direction. Copper layers have a highly ordered fcc structure. Cobalt layers, mainly fcc with several stacking faults, are locally much more disordered than copper layers.