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 evolution of the first-harmonic component of the GMI voltage with the axial DC applied magnetic field can be suitably described in terms of the evolution of the circumferential magnetic permeability. With regard to the second-harmonic component, its amplitude sensitively evolves with the axial DC magnetic field and its appearance is associated to an asymmetry in the circular magnetization process. A simple rotational magnetization model is presented where the harmonic components of the GMI voltage are estimated through Fourier analysis.