Abstract
Many nanocrystalline Fe-Nb-Cu-B-Si ribbons are known to show magnetic anisotropy influenced by macroscopic magnetoelastic interaction. This interaction comes from surfaces exerting force on ribbon interior. Raman spectroscopy is used to investigate surface properties of the 4.5 at.% Si member of Fe-Nb-Cu-B-Si series to indicate sources of the force or the preferred surface crystallization. Hematite and magnetite have been identified on certain surface locations, whereas no Raman response was observed on major surface area. Unlike as-cast state and vacuum annealing, the ferrous oxides appear most abundant after higher temperature Ar annealing similarly as off-axis magnetic anisotropy evolves with annealing. Existence of an silicon oxide layer on the genuine surfaces was excluded by response to intentional deposition of SiO₂. Minor carbon contamination appears to enable ferrous oxides to be revealed by Raman spectroscopy.

Key words
nanocrystalline materials, magnetic properties, surface properties, Raman spectroscopy

Full text (399 KB)