Co/Cu solid solution prepared by ion implantation

A Co/Cu solid solution is prepared by direct implantation of 200 keV Co ions into Cu targets. The maximum concentration at this ion energy is limited to 25 at.% Co due to sputtering. Magnetic measurements show a spin-glass behaviour, as expected for a
solid solution of Co in Cu. At about 630 K the solid solution starts to decompose into
clusters. After heat treatment, the sample shows ferro- and superparamagnetic behaviour, indicating that the size of the clusters is broadly distributed.