Study of stress annealing effect on giant magneto-impedance of Fe-based ribbons

Abstract

Fe-based nanocrystalline ribbons were successfully prepared. The giant magneto-impedance (GMI) effect that was found in these studies could be effectively increased by temperature annealing together with stress annealing. After applying a certain stress, the same GMI effect can be obtained with a much lower annealing temperature. In the present paper, it was found that the crystallization of Fe-based sample can reach its best GMI effect with a ratio of ΔZ to Z at 1141% at 500°C annealing and 53 MPa, showing that the stress and temperature annealing is an effective way of annealing which can improve the material soft magnetic properties and the GMI effect and also reduce the annealing temperature (GMI = ΔZ/Z = {[Z(H) − Z(H max)]/Z(H max)}*100%, Z(H) and Z(H max), respectively the impedance value under any additional magnetic field and the maximum magnetic field). The preferential agglomeration along the transverse direction in the ribbon is formed during stress annealing, leading to the transverse magnetic anisotropy of the iron-based nanocrystalline ribbon, which influences the GMI effect of the iron-based nanocrystalline.