Study of the Giant Magnetic Impedance Effect in Electro-depositied Complex Wire

The Giant Magnetic Impedance（GMI）effect of complex wires which were produced by pulse electrodeposing Fe-Ni alloy over cylindrical Cu substrates has been studied. It is found that the soft magnetic property is better，and the GMI effect of the sample is stronger. The maximum GMI ratio is 27.19% among these samples. The dependance of the impedance and GMI ratio on DC magnetic field is influenced by magnetic anisotropy in magnetic microtubes of complex wire. The variation of GMI effect with AC current frequency is investigated. The experimental results show that the GMI effect of the complex-structure sample Fe17 Ni83 has a very low critial frequency of 30 kHz（GMI=9.95%）and charicteristic frequency 300 kHz（GMI=27.19%）and its cutoff frequency is 10 MHz（GMI=10.36%）. Not only such low critial and charicteristic frequency but also wider work frenquency range are of importance for technological applications.