Field dependence of second-harmonic amplitude of magnetoimpedance in FeCoSiB joule heated wires

The existence of a second-harmonic component of the giant magnetoimpedance (GMI) voltage in an amorphous FeCoSiB Joule heated wire is analysed. The ev olution of the first-harmonic component of the GMI voltage with the axial D C applied magnetic field can be suitably described in terms of the evolutio n of the circumferential magnetic permeability. With regard to the second-h armonic component, its amplitude sensitively evolves with the axial DC magn etic field and its appearance is associated to an asymmetry in the circular magnetization process. A simple rotational magnetization model is presente d where the harmonic components of the GMI voltage are estimated through Fo urier analysis. (C) 2001 Elsevier Science B.V. All rights reserved.