The Study of Co-Cu Heterogeneous Alloy Thin Films by NMR Method

In the present work we discuss the structure of magnetic layer in magnetron sputtered Co/Cu multilayers with ultrathin magnetic layers (effective layer thicknesses $d_\mathrm{Co}\approx3.5$ and 4.5 Å) obtained by means of $^{59}$Co NMR method. In spite of such a small effective thicknesses of sputtered layers it has been found that the NMR spectra are the superposition of two peaks with central frequencies $f_1=$190–196 MHz and $f_2=$208–213 MHz which obviously correspond to Co-atoms which have 0 and 1 Cu-atom in the nearest-neighbor shell indicating that cobalt preferably forms clusters with large number of atoms involved.