Local structure and magnetic properties of Mn and Co co-doped SiC films

Mn and Co co-doped SiC films were deposited on Si substrates by magnetron sputtering technique. The structure and magnetism of the films were investigated systematically. X-ray diffraction and X-ray photo-electron spectroscopy clearly show that the films are composed of 3C-SiC, in which Mn atoms substitute for the C sites of SiC lattice and Co atoms form CoSi compounds. The valence analysis displays that Mn and Co elements exist in the form of Mn2+ and Co2+ ions in the films, respectively. The magnetic analysis indicates that the films are ferromagnetic at room-temperature and the saturation magnetization increases with increasing Mn substitution concentration. There are two ferromagnetic phases in the films, the Curie temperature at 240 K is associated with CoSi nanoparticles, while the Curie temperature observed above 300 K come from Mn substitution and some extended defects. These features reveal that the room-temperature ferromagnetism of Mn and Co co-doped SiC films is intrinsic property of the material.