Magneto-transport properties of amorphous Ge1−xMnx thin films

Amorphous Ge1−xMnx thin films were grown in order to expand the solubility limit of Mn. The amorphous Ge1−xMnx thin films were grown on (1 0 0)Si substrate at 373 K by using a thermal evaporator. The solubility of Mn in amorphous Ge1−xMnx thin films reaches up to 17 at.%. The amorphous Ge1−xMnx thin films are ferromagnetic and the TC is ∼150 K. The largest saturation magnetization of amorphous Ge1−xMnx thin films is ∼100 emu/cm3 for x = 0.118 at 5 K. The variation of electrical resistivity with respect to temperature reveals that the amorphous Ge1−xMnx thin films have semiconductor characteristics. The in-field electrical resistivity of amorphous Ge1−xMnx thin films is lower than the zero-field electrical resistivity when T < TC, but the reverse is true when T > TC. However, the in-field electrical resistivity of amorphous Ge1−xMnx thin films is always higher than the zero-field electrical resistivity when x > ∼12 at.%. Magneto-transport characteristics of amorphous Ge1−xMnx thin films show anomalous Hall phenomenon and negative magnetoresistance when T < TC. The results suggest that the Mn atoms in amorphous Ge1−xMnx thin films be related to spin dependent scattering depending on magnetization.