Modeling of domain structure and anisotropy in glass-covered amorphous wires

Giant magnetoimpedance (GMI) at 10 MHz and longitudinal magnetization curves are used to investigate the anisotropy of ${\mathrm{Co}}_{\mathrm{68.15}}{\mathrm{Fe}}_{\mathrm{4.35}}{\mathrm{Si}}_{\mathrm{12.5}}{\mathrm{B}}_{\mathrm{15}}$ wires, glass-covered and after glass removal. The high resolution GMI response to the field shows hysteresis and large Barkhausen jumps, in good agreement with those observed in the magnetization curves. These are modeled through superposition of the response of the inner core and outer shell of the wires. The GMI response is calculated using the differential susceptibility deduced from the model, thus relating the domain structure to the observed magnetoimpedance.