Investigations of the compositional distribution in epitaxially grown CoCr thin films with enhanced saturation magnetisation

The compositional distribution in a Co78Cr22 film grown epitaxially on Ru/mica by electron beam evaporation was investigated using spin-echo 59Co nuclear magnetic resonance (NMR) and preferential chemical etching of Co. NMR revealed evidence for the occurrence of drastic compositional separation producing a Co-enriched component containing almost pure Co. Chemical etching revealed a particularly fine distribution of Co-enriched regions. These results are consistent with the proposition that the enhanced saturation magnetisation (Ms) observed in these films is attributable to enhanced compositional inhomogeneities.