Magneto-impedance and ΔE measurements of iron- and cobalt-based amorphous wires

Abstract

Magneto-impedance and /spl Delta/E measurements of amorphous wires having the compositions Fe/sub 77.5/Si/sub 10/B/sub 15/ and Co/sub 72.5/Si/sub 12.5/B/sub 15/ in the as-quenched and annealed states are presented. The results are interpreted in the light of the widely accepted core-shell domain models for positively and negatively magnetostrictive amorphous wires respectively. It is concluded that in wires of Fe/sub 7.5/Si/sub 10/B/sub 15/ the radial easy axis structure in the shell of the as-quenched wire weakens after light annealing, eventually giving way to a circumferential structure when surface crystallization occurs. In wires of Co/sub 72.5/Si/sub 12.5/B/sub 15/ significant circumferential anisotropy is inferred in all states of annealing studied.