Studies of giant magnetoimpedance effect of Co-rich microwires in wide frequency range



The GMI effect in Co-rich amorphous microwires with nearly-zero and negative magnetostriction constant has been investigated in the frequency range from a few MHz up to 10 GHz using conventional impedance analyzer based technique and microwave waveguide method. The GMI response of the order of 200% has been observed for all samples at MHz frequencies, while only one samples demonstrated considerable GMI ratio of about 60% at GHz frequencies. This can be explained by the fact that impedance dependence on external magnetic field in the microwaves range is affected not only by the magnetic softness of the wire material but also by the magnetic resonance conditions in the not saturated sample. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)