High frequency behavior of soft magnetic wires using the giant magnetoimpedance effect

We have investigated the high frequency properties of several amorphous and polycrystalline wires mounted as inner conductors in coaxial lines. A stat ic magnetic field was applied along the win axis, The impedance spectra of the wires, measured using a network analyzer, show peaks in the real part o f the impedance, which shift to higher frequency with the strength of the s tatic field, a behavior typical of ferromagnetic resonance. The theoretical resonance condition predicts a straight line on an f(o)(2)-H-o plot, where f(o) is the resonance frequency and H-o is the resonant field, whose slope depends only on the saturation magnetization, M-s, of the material. All ou r wins obey this relation, and the values of M-s calculated from the slopes are in good agreement with those measured directly using a vibrating sampl e magnetometer. (C) 1998 American Institute of Physics.