High-frequency magnetoimpedance on annealed amorphous magnetic wires with different magnetostriction constants

Amorphous Co-based and Fe-based magnetic wires having magnetostriction constants ranging from nearly zero positive values to large positive values, have been submitted to different thermal treatments (dc Joule heating and furnace annealing) to relax internal stresses produced during fabrication and to possibly induce different magnetic anisotropy. High-frequency (up to 6 GHz) magnetoimpedance GMI response has been studied as a function of frequency and thermal treatment in order to experimentally investigate the role of all these parameters on GMI.