Soft Magnetic Properties and High-Frequency Characteristics in FeCoSi/Native-Oxide Multilayer Films.

Magnetic properties of FeCoSI/native-oxide multilayer films, prepared by DC magnetron sputtering and exposure to oxygen in a sequence, have been investigated. It is found that the appropriate thicknesses of the native-oxide layers and FeCoSi layers are very important in decreasing coercivity H[subc] of the multilayered films, which may be caused by the exchange coupling between the FeCoSi particles through the oxide. A minimum H[subc] value of 8.4 Oe was obtained for the [FeCoSi (20 A)/native-oxide]50 multilayer film with the largest in-plane uniaxial anisotropy field 11k of 130 Oe. The real part μ' of complex permeability of this sample is more than 100 and flattens almost to 2.5 GHz, while the imaginary part μ" is less than 50 for f < 2.5 GHz. The ferromagnetic resonance frequency is as high as 3.9 GHz, implying that the film is promising for high-frequency applications. [ABSTRACT FROM AUTHOR]