Comparison between surface and bulk hysteresis loops in amorphous wires

A comparison between the surface magnetic properties obtained by Kerr effect and the bulk properties measured by a conventional fluxmetric method in magnetostrictive FeSiB amorphous wires is introduced here. This comparison gives us a direct information from both the regions. Particular attention is paid to coercivity and magnetization reversal process. The appearance of a bistable low-field axial hysteresis loop suggests the existence of an axial magnetization component at the surface. Also, the dependence of coercivity with applied torsion is quantitatively analyzed considering internal and applied stresses.