STRUCTURAL AND SOFT MAGNETIC-PROPERTIES OF NANOCRYSTALLINE (FE,CO,NI)-TA-C FILMS WITH HIGH THERMAL-STABILITY

Nanocrystalline (Fe,Co,Ni)75-85-Ta6-9-C10-16 films were prepared over the whole Fe-Co-Ni composition range by annealing sputter-deposited amorphous alloys. Good soft magnetic properties have been obtained over a wide Fe-Co-Ni composition range owing to the nanocrystalline effect. In the films with the coercivity less than 60 A/m, the highest saturation magnetization I(s) was about 1.7 T. The composition dependence of I(s) and magnetostriction in the films is similar to that of bulk Fe-Co-Ni alloys because the phases of precipitated Fe-Co-Ni base crystallites in the films are almost the same as those in the bulk alloys. In these films, soft magnetic properties are maintained even after annealing at 973 K because the nanocrystalline structure is stabilized by finely dispersed TaC. Further high thermal stability has been achieved for the films considered to have small intrinsic K1. Based on the relation between uniaxial anisotropy and permeability, the effect of the intrinsic magnetocrystalline anisotropy or the anisotropy field on the local anisotropy dispersion is qualitatively discussed as well.