The effects of Co addition on the structure and the saturation magnetization of Fe16N2 were investigated. Enhancement of the formation of Fe16N2 phase by Co addition was observed. Films with 5–25 at % Co contents deposited at proper conditions exhibit a high saturation magnetization up to the range of 2.5–2.7 T. The saturation magnetization of (Fe, Co)16N2 alloys phase is expected to be 2.8–2.9 T, which is as large as that of Fe16N2. This demonstrates that proper Co addition does not induce notable changes in the high saturation magnetization of the Fe16N2.

Soft magnetic properties and thermal stability of Fe–Ti–N alloys films have been investigated. Thin films with composition in the range of 8–10 at. % Ti, 10.5–14 at. % N, and balance Fe were prepared by reactive sputtering method. The films exhibit good soft magnetic properties in the as-deposited condition without any post heat treatment, e.g., low coercivity Hc∼1.5 Oe, high permeability μ∼3200 at 1 MHz and very high saturation magnetization 4πMs∼24 kG. The thermal stability of these films was also found to be good, e.g., Hc was less than 2 Oe, and 4πMs was higher than 23 kG for the films annealed up to 500 °C. The high electrical resistivity ρ∼100 μ Ω cm of the films can minimize the eddy current loss in the high frequency applications. The combination of high 4πMs and relatively high anisotropy field Ha∼10 Oe in the film is conductive to the suppression of the undesirable ferromagnetic resonance interfere up to the GHz frequency range.

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