MBE growth and properties of GeMn thin films on (001) GaAs

Abstract: We have prepared Ge0.92Mn0.08 thin films by molecular beam epitaxy (MBE) on semi-insulating (001) GaAs substrates and investigated their transport and magnetic properties. We have found out that the resulting properties of the thin films are highly dependent on the substrate temperature T s. The sample grown at T s=130°C exhibited a pronounced negative magnetoresistance and anomalous Hall effect even up to room temperature most probably due to the presence of substitutional Mn in the Ge host matrix and the formation of the Ge5Mn3 phase. Because these phenomena were not detected for samples grown above 130°C, we believe that these are due to the T s dependence of Mn distribution in Ge0.92Mn0.08 thin films and the degree of the interdiffusion of Ge, Ga and As atoms at the Ge0.92Mn0.08/GaAs interface. [Copyright &y& Elsevier]