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Soft magnetic properties of Fe-TM-C-N (TM. Zr, Nb) films, fabricated by rf reactive sputtering in ArtNz atmosphere, were investigated. The as-deposited films having mixed phases of amorphous and a -F e or mostly crystalline aFe phase showed nanocrystalline structure upon annealing. The best soft magnetic properties achieved in these films are; EI, of 0.06 Oe, p~ of 2750 (1MHz) and 4 of 16.8 kG in Fe-Zr-C-N film and H, of 0.31 Oe, pe of 2100 (1MHz) and 4 n M s of 15.5 kG in Fe-Nb-C-N film. The fine grained a-Fe structure, together with very fine TM(C,N) precipitates which were formed at an early stage of crystallization, is considered to be one of the main factors for the excellent soft magnetic properties. The Fe-Zr-C-N films exhibit better soft magnetic properties than those of the Fe-Nb-C-N films, which is considered to be due to the magnitude of the formation enthalpy.of N*gas, PN2 ,was controlled in the range of 0-10% keeping the total gas pressure of l~l O -~ Torr constant. . The deposition rate was 470-620 k m i n , mainly depending on PN, at the power density of 3.82 watts/cm2 The films were annealed at 450-700 "C for 30 min in vacuum. The composition of films was analyzed by Auger electron spectroscopy (AES), and some of films also by Rutherford backscattering spectroscopy (RBS). The saturation magnetization (4 zMx) and coercive force (Hc) were measured by a vibrating sample magnetometer (VSM). The effective permeability (,U$) was measured by a permeability measurement system using 8-figure coil. The microstructure was investigated by transmission electron microscopy (TEM) and X-ray Mactometry (XRD).

The thickness dependence of magnetic properties was experimentally investigated in nanocrystalline FeHf-N thin films fabricated by a RF magnetron sputtering method. In order to investigate the thickness effect on their magnetic properties, the films are prepared with different thickness ranges from 90 nm to 330 nm. It was revealed that the coercivity of the thin film increased with film thickness. On the contrary, the saturation magnetization decreased with film thickness. On the basis of the SEM and TEM, an amorphous phase forms during initial growth stage and it changes to crystalline structure after heat treatment at 550 o C. Nanocrystalline Fe-Hf-N particles are also generated.