Peculiar behavior of the magneto-impedance in Fe-based amorphous wires under torsion

Abstract The inductive ( ωL ) and resistive ( R ) components of the impedance of an amorphous wire (Fe 77.5 Si 7.5 B 15 ) subjected to torsional stresses are measured. For a critical value of the AC driving current L abruptly increases due to irreversible magnetization processes in the circumferential configuration. Suitable combinations of the AC driving current amplitude and frequency give rise to a peak in the resistive variations and a minimum in the inductance. The inductance shows a bistable asymmetric hysteresis loop ( L vs. H ). The torsional stress increases the coercivity of the longitudinal hysteresis loop of the wire but favors the reaching of the saturation magnetization at lower fields.