Electric and magnetic properties of Cr-doped SiC films grown by dual ion beam sputtering deposition

Cr-doped SiC thin films have been fabricated on Al₂O₃ and Si substrates by using dual ion beam sputtering deposition at room temperature. The films have been characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy (XPS). XRD and TEM results show that the films are amorphous. The XPS studies confirm that the Cr³⁺ ion occupies the Si site in amorphous SiC (a-SiC). The temperature dependence of resistivity measurements reveals that Cr doping does not change the semiconducting property of the a-SiC films. The magnetic measurements reveal that the Cr-doped a-SiC thin films are ferromagnetic with Curie temperature T_c above room temperature. The carriers mediate the interaction of the magnetic ions, resulting in this ferromagnetic behaviour.