Magnetism, structure and the effects of thermal aging on (Fe1-xMnx)(73.5)Si13.5B9Nb3Cu1 alloys

Amorphous alloys of (Fe1-xMnx)(73.5) Si13.5B9 Nb3Cu1, where x = 0, 0.05, 0. 10, 0.15, were prepared by vacuum melt-spinning. Anneals performed at or ab ove the crystallization temperature led to the formation of a nanostructure where the primary phase is a body centered cubic or DO3 FeSi phase embedde d within an intergranular amorphous phase. The saturation induction of the x = 0.05 alloy is 1.19 T, slightly lower than the parent alloy. Prolonged t hermal aging led to an enhancement in the soft magnetic properties. This ch ange occurs at soak times near 6000 s and corresponds to a decrease in the anisotropy and coercivity, and an increase in the remanent magnetization. E XAFS studies suggest that the Mn partitions during crystallization and ther mal aging to the grain boundary regions may play an important role in enhan cing the exchange coupling of the aged samples by increasing the Curie temp erature of the amorphous intergranular phase.