Permeability and magnetoimpedance in [formula omitted] wire under torsional stress

The complex permeability spectra and the magnetoimpedance (MI) are measured as a function of torsional stress and torsion angle in [formula omitted] amorphous wire. The permeability spectra show irreversible and reversible relaxation with relaxation frequencies of 40 and 300 kHz, respectively. The static permeability resulted from the irreversible magnetization decreases with torsion angle for a negative direction, but increases with a positive angle. The MI profile shows one symmetric peak for the positive torsion angle, which is same MI behavior as in the case of zero torsion. However, there is a hysteresis in the MI profile for negative torsion, that is, there are two asymmetric peaks for decreasing field and one peak for increasing field.