The giant magneto-impedance effect of current-annealed Fe-based ribbons

The influence of current annealing process on the giant magneto-impedance(G MI) effect of Fe84Zr8Nb3.5B3.5CU1 ribbons was studied. The obtained results showed that with increasing annealing current, the GMI ratio Delta Z/Z(Del ta Z/Z = (Z(H) - Z(H-max))/Z(H-max)) is enhanced. The maximal GMI ratio of about 62% is obtained for the sample annealed at 820 mA for 10 min, while t he sensitivity can reach a value up to about 0.23 % (A/m)(-1). In combinati on with the evolution of electrical and soft magnetic properties, the depen dence of the GMI effect on the frequency and applied longitudinal field has been discussed by means of skin effect.