Neutron irradiation effects on polycrystalline Ge1−xMnx thin films grown by MBE

Polycrystalline Ge1−xMnx thin films were irradiated with neutrons, and their electrical and magnetic properties have been investigated. As-grown specimens have p-type carriers and electrical resistivities are in the range of 1.3 × 10−4–5.2 × 10−4 ohm cm at room temperature. After the irradiation of neutrons the carrier type is not changed, but the electrical resistivities increase with the amount of neutron irradiation. In addition, some of neutron-irradiated Ge1−xMnx thin films transform from the semiconductor characteristics into the metallic characteristics at low temperature. The saturation magnetizations of neutron-irradiated Ge1−xMnx thin films decrease, but the coercive forces increase with the irradiation amounts. The XRD analysis suggests that the defects generated by the neutron-irradiation cause the change of electrical and magnetic properties of Ge1−xMnx thin films exposed to neutron irradiation.