Magnetic properties of cobalt clusters embedded in a copper matrix

The magnetic properties of ${\mathrm{Co}}_{\mathrm{N}}$ clusters (N=1, 13, 19, and 43) embedded in copper matrix are studied using the discrete-variational local-spin-density-functional method and embedded cluster models. Single Co atom in Cu is found to be nonmagnetic, while all the rest Co clusters in Cu are still magnetic with reduced moments. Cu atoms in granular Co/Cu system reveal similar spin polarizations to Cu atoms in Co/Cu multilayers as manifested in recent x-ray magnetic circular dichroism measurements.