Abstract: In order to investigate the impedance of Co-based amorphous wires as a function of applied magnetic field intensity and frequency,a self-made device for giant magneto-impedance effect is made by using common devices in laboratory.Comparing with electromagnetic explanation of impedance,the experimental results are good in agreenent with the theory.The rate of change of impedance is up to 80% under an external magnetic field of 10 mT and a driving frequency of 40 MHz.Derived from data-fitting,the permeability tends to decreasing immediately with an increasing intensity of magnetic field.

Key words: giant magneto-impedance effect, amorphous wires, skin effect, permeability