Radial dependence of circular magnetic permeability of amorphous magnetic microwires

Abstract

Field and frequency dependencies of the permeability bring information about the magnetization dynamics in the material. In this work, a novel method of reconstruction of the permeability radial dependence in amorphous magnetic microwires with circumferential anisotropy in the near-surface region is suggested. The approach is based on the dependence of the wire impedance on the permeability. In a low MHz frequency range, for fixed current amplitudes, the deviation of Z dependence from that predicted by classical electrodynamics can be attributed to permeability’s spatial distribution. Thus, the latter can be reconstructed from the frequency dependence of the impedance. Permeability radial distributions in the near-surface region were obtained for the Co69Fe4Cr4Si12B11 microwires with low negative magnetostriction with metallic core diameter 90 µm. Frequency range 2–10 MHz allowed the inspection of the layer from 0.6 of the wire radius to its surface.