Giant magneto-impedance effect in Fe4.5Co67.5Mn0.5Si12B15 amorphous wires

The Giant magneto-impedance of amorphous wires with a nominal composition of Fe4.5Co67.5Nb0.5Mn0.5Si12B15 has been investigated using a HP4192A impedance analyzer in the frequency range from 5 Hz to 13 MHz. The results show that there exists an optimum frequency where the GMI shows a maximum for all samples investigated, and the maximum GMI values of the as-cast wire and the wire annealed at 350°C are 73 and 71%, respectively. GMI effect for the as-cast wire at the frequency range <1 MHz is much higher than those for the annealed samples, and in the case of frequency range >1 MHz GMI effect is better than that of the as-cast state. GMI(Z)max shows a maximum with annealing temperature and optimum annealing temperature is 350°C in the study. Both magneto-resistance and magneto-reactance of the as-cast wire have also been investigated.