Mn-doped amorphous Si:H films with anomalous Hall effect up to 150 K

Structural, magnetic, and electrical properties were investigated of Mn-doped amorphous silicon films prepared by magnetron sputtering with and without hydrogen. Ferromagnetism at room temperature was observed and no clusters or second phases were detected from x-ray diffraction and high-resolution transmission electron microscopy analyses. Hydrogenation enhances saturation magnetization, carrier concentration, and Curie temperature by about 500%, 300%-500%, and 100 K, respectively. The M-T curve of hydrogenated sample fits very well by combination of Curie-Weiss law and three-dimensional spin-wave. Anomalous Hall effect was reproducibly obtained at 150 K. These suggest that the origin of ferromagnetism may arise from the carrier mediated mechanism.