Study of CoNbFe films deposited by DC magnetron sputtering

CoNbFe films were deposited by DC multisource sputtering and unbalanced DC single-magnetron sputtering. The film structures and magnetic properties were studied as a function of film composition and deposition parameters. Transmission electron microscopy study of the film structure and the measurement of film resistivity showed that films containing more than 12 at.% of Nb are amorphous, with a transition to crystalline films occurring in the 12-9-at.% range. The addition of small amounts of Fe reduces the H_c of the as-deposited films. For Co_87-xNb₁₃Fe_x films, the optimum Fe content is 5.0 at.%. The minimum H_c of CoNbFe films made by the multisource was 17 A/m, with a large anisotropy field H_k. Films made from a composite target on a single unbalanced magnetron had a minimum H_c of 6 A/m and a minimum H_k of 15 A/m. This is attributed to the low-energy and high-density ion bombardment of the growing films and the smaller angle of incidence from the single source