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 Co
71.4
Fe
4.6
Si
9.6
B
14.4
amorphous alloy. Domain wall stabilization is shown to be the dominant factor resulting in decreasing μ and increasing H
c
and K during low temperature annealing. Annealing near T
c
results in an isotropic magnetic structure due to domain wall relaxation, and annealing above T
cry
results in magnetically hard crystalline particles. It is concluded that treatments capable of producing a magnetically isotropic structure can produce the best soft magnetic materials.