Amorphous ferromagnetic wire with a highly positive saturation magnetostriction coefficient, made of Fe sub 73.5 Si sub 13.5 B sub 9 Nb sub 3 Cu sub 1 , was simultaneously submitted to both, an AC current passing through it and a torsional stress, in order to induce a helical magnetic anisotropy in the wire that modifies its domain structure and therefore the magnetic response of the sample. The aim of this work is to study the reactive, resistive and impedance behaviour in this Fe-rich wire, submitted to different applied torsional stresses, and for several values of the AC current amplitude through the wire (5-20 mA sub rms ), in the low frequency range, f < MHz. The experimental results are explained on the basis of the core-shell model.