Axial-field-dependent circular susceptibility in Fe-rich amorphous wires

Abstract The longitudinal magnetic field dependence of low-frequency circular susceptibility, χ ( H ), is measured for (Fe 1− x Cr x ) 77.5 Si 7.5 B 15 ( x =0,0.05,0.1, and 0.15) amorphous wires of radius r 0 =0.07 mm. In order to explain the experimental results, on the basis of the widely accepted core–shell model, we consider that there are a constant axial anisotropy K c in the core and a radius-dependent radial anisotropy K s ∝ r 8 / r 0 8 in the shell, both K c and K s being functions of stress-energy constant λ s σ 0 . A formula for χ ( H ) is derived from this model. The experimental data fits indicate that the magnetic structure can be well described by the improved core–shell model with reasonable values of λ s .