PREPARATION OF FE-N FILMS BY RF-SPUTTERING

Fe-N films over a wide compositional range have been prepared by the reactive sputtering method. Fe-N sputtered films were composed of a single or two phases such as ζ-Fe2N, ε-Fe3.02N, γ′-Fe3.82N, γ′-Fe4N and α-Fe; however, an unknown phase was observed at a higher nitrogen pressure. A remarkable preferred orientation of the ε-Fe3.02N (110) plane parallel to the film surface was observed. The Curie temperature of the sputtered γ′-Fe3.82N sample was 490° C, which was almost the same as that of γ′-Fe4N prepared by metal nitriding. The saturation magnetization, σs, of the sputtered Fe-N samples decreased from 151.8 to 42.4 e.m.u.g-1 with increasing nitrogen content from 7.94 to 24.87 at%, and its coercive force,1Hc was found to lie in the range 150 to 600 Oe in the powder form at room temperature. © 1990 Chapman and Hall Ltd.