A model for asymmetric giant magnetoimpedance in field-annealed amorphous ribbons

摘要

A phenomenological model for the asymmetric giant magnetoimpedance (GMI) infield-annealed amorphous ribbons is developed. The effect of a surfacecrystalline layer on the GMI response is described in terms of an effectivebias field appearing due to a coupling between the crystalline layer andamorphous phase. It is shown that the presence of the bias field changesdrastically the GMI profile. At low frequencies, the domain-walls motion leadsto a steplike change in the GMI response. At high frequencies, the domain-wallsmotion is damped, and the GMI profile exhibits asymmetric two-peak behavior.The calculated dependences are shown to be in a qualitative agreement withresults of experimental studies of the asymmetric GMI in field-annealedCo-based amorphous ribbons.