Effects of Ni doping and structural defects on magnetic properties of annealed SiC films

Ni-doped SiC films deposited on Si (100) substrates prepared by RF-magnetron sputtering were discussed in this paper. The results show that with reference to the as-deposited as well as annealing at 800 °C. C atoms were substituted by Ni atoms in the 3CSiC lattice and Ni-related secondary phase cannot be detected. After annealing at 1200 °C, the crystal quality improved obviously while the majority of Ni atoms form the Ni2Si secondary phase. Temperature dependent on resistivity reveals that the conduction mechanism is dominated by Mott variable range hopping behavior for the Ni-doped SiC films, confirming that the carriers are localized. All the films are ferromagnetic at 300 K and annealing can evidently improve the room-temperature (RT) ferromagnetism. The bound magnetic polarons should be responsible for the RT ferromagnetism of the Ni-doped SiC films.