Magnetic properties and structure evolution of amorphous Co-C nanocomposite films prepared by pulsed filtered vacuum arc deposition

The magnetic properties and structure evolution of CoxC1-x (x=44, 65, 71 at . %) nanocomposite films prepared by pulsed filtered vacuum arc deposition were studied. The as-deposited films consist of amorphous Co clusters in a- C and are soft ferromagnets. The low coercivity in the amorphous films is d ue to the very low anisotropy of the amorphous Co clusters. After annealing in vacuum at 350 degrees C for 1 h, the Co clusters crystallize and these films become magnetically harder. The magnetic hardening is attributed to t he enhanced magnetic anisotropy of the nanocrystals. Their saturation magne tization reduces slightly. This is attributed to the reduction of the densi ty of states at the Fermi level caused by the crystallization of the amorph ous Co clusters. (C) 2000 American Institute of Physics. [S0021-8979(00)030 21-8].