Magnetoimpedance and magnetization processes in amorphous wires under torsion

An investigation of the effects of torsion on magnetoimpedance of CoFeBSi as-cast amorphous wires is presented. For this study we used the complex permeability as a function of frequency in the range 100 Hz-13 MHz. An asymmetric behavior (a maximum for clockwise torsion, a monotonous decrease for counter-clockwise torsion) was observed for real permeability plots at constant frequency, as a function of torsion. This behavior is interpreted in terms of an induced anisotropy with helical geometry