Effect of annealing temperature on permeability and giant magneto-impedance of Fe-based amorphous ribbon

The effect of annealing treatment on permeability and magneto-impedance in Fe73Cu1Nb3.5Si14B8.5 amorphous ribbons was investigated systematically. The magneto-impedance profiles were measured as a function of the external magnetic field at various frequencies up to 10 MHz. The real and imaginary parts of the complex permeability were measured in a frequency range of 0.1–10 MHz under different applied ac field. The results indicated that the longitudinal permeability resulting from domain wall motion decreased drastically after annealing treatment, but the permeability resulting from the rotational magnetization increased with increasing annealing temperature up to 540 °C and then decreased at higher temperatures. The largest magneto-impedance effect was observed in the nanocrystalline alloy. The correlation between the soft magnetic properties and the magnitude and sensitivity of the GMI effect was discussed.