Formation of Mn5Ge3 nanoclusters in highly diluted MnxGe1−x alloys

Films grown at TG=160 °C reveal the presence of Mn5Ge3 nanoclusters embedded into the Ge crystalline host matrix doped by residual Mn atoms. Mn5Ge3 nanoclusters show different features depending on the nominal Mn concentration in the MnxGe1−x films. However, results evidence the existence of an Mn concentration threshold, around x=0.01, below which crystallites formation is prevented. Our study evidences the relevant role of a suitable choice of the epitaxial growth parameters. These results make this material a promising candidate for spintronic applications.