Effects of microaddition of cerium on the magnetic properties of Fe80B16Si2C2metallic glass

The addition of cerium in parts-per-million quantities to an amorphous FeBSiC alloy has been found to reduce significantly the rate of annealing embrittlement of melt-spun metallic glass ribbons, as reported elsewhere. The concomitant changes in magnetic properties (coercivity, large-field magnetization, 60-Hz loss, and domain structure) are discussed. The addition of cerium in general tends to degrade the dc magnetic properties of the alloy in the as-quenched condition, although much of the degradation is eliminated with a magnetic anneal. Ribbons produced from a casting with nominal cerium content of 100 atomic ppm are apparently free of maze domains as quenched, with planar domains which are largely or entirely transverse to the ribbon axis. In contrast, the samples with 500 atomic ppm of cerium are very heavily dominated by maze domains, while the base alloy shows a fairly typical domain structure with a scattering of maze domains. A tentative interpretation of these results is offered, in which the cerium plays a role in this glass which is analogous to its role in the refining of polycrystalline alloys.