High frequency characteristics of as-sputtered Co-Ni-Fe-N soft magnetic thin films

Co-Ni-Fe-N soft magnetic thin films with excellent high frequency characteristics were fabricated by a N/sub 2/ reactive RF magnetron sputtering method. The nitrogen partial pressure (P/sub N2/) was varied in the range of 0/spl sim/10%. As P/sub N2/ increases in this range, the saturation magnetization (B/sub s/) linearly decreases from 19.8 kG to 14 kG and the electrical resistivity (/spl rho/) increased from 27 /spl mu//spl Omega/cm to 155 /spl mu//spl Omega/cm. The coercivity (H/sub c/) exhibits the minimum value at 4% P/sub N2/. The magnetic anisotropy field (H/sub k/) is in the range of 20/spl sim/40 Oe. The high frequency characteristics of (Co/sub 22.2/Ni/sub 27.6/Fe/sub 50.2/)/sub 100-x/N/sub x/ films are excellent in the range of 3/spl sim/5% P/sub N2/. Especially, the effective permeability of the film fabricated at 4% P/sub N2/ is about 800, which is maintained up to 600 MHz. This film exhibits B/sub s/ of 17.5 kG, H/sub c/ of 1.4 Oe, /spl rho/ of 98 /spl mu//spl Omega/cm, and H/sub k/ of about 25 Oe. The corrosion resistance of (Co/sub 22.2/Ni/sub 27.6/Fe/sub 50.2/)/sub 100-x/N/sub x/ is improved with the increase of N concentration.