Fabrication of nanocrystalline Fe-Co-Ta-N magnetic films with high saturation magnetization and excellent high-frequency characteristics

Abstract

As-deposited Fe-Co-Ta-N soft magnetic thin films with a thickness of 250 nm were fabricated to achieve high saturation magnetization and excellent high-frequency characteristics. During sputtering, the input power was fixed at 450 W and the nitrogen partial pressure varied from 0% to 10%. In these films, the values of saturation magnetization and coercivity that were obtained were 17-23 kG and 3-6 Oe, respectively. The Fe78Co8Ta9N5 (4% P-N2) film exhibits excellent high-frequency characteristics with an effective permeability of about 2000, which is maintained up to 700 MHz. Also, this film has B-s=21 kG, Hc-hard=3 Oe, rho=100 muOmega cm, and H-k=20 Oe. These high-frequency characteristics could result from the high values of the electrical resistivity and the magnetic anisotropy field. Furthermore, the corrosion resistance of these films was improved by the addition of nitrogen to give characteristics better than those of Co-Ni-Fe and Fe-Hf-N films. (C) 2003 American Institute of Physics.