Electron microscopy of Co/Fe/B/Si amorphous alloys

Changes in magnetic structures with annealing are studied using Lorentz electron microscopy and are correlated with changes in magnetic properties for the Co71.4Fe4.6Si9.6B14.4amorphous alloy. Domain wall stabilization is shown to be the dominant factor resulting in decreasing μ and increasing Hcand K during low temperature annealing. Annealing near Tcresults in an isotropic magnetic structure due to domain wall relaxation, and annealing above Tcryresults in magnetically hard crystalline particles. It is concluded that treatments capable of producing a magnetically isotropic structure can produce the best soft magnetic materials.