Thickness Dependence of Mössbauer Parameters for Fe_{78}Si_{9}B_{13} Metallic Glass Ribbons

Changes in magnetic microstructure of Fe78Si9B13 ribbons were investigated by the Mossbauer spectrometry as a function of their thickness. The latter decreases inversely with the quenching wheel velocity. Amorphicity of the samples was checked by X-ray diffraction and the Mossbauer spectrometry. Average values of hyperfine magnetic fields do not appreciably differ with the production velocity. On the other hand, notable deviations are observed in the position of a net magnetic moment. After annealing with moderate temperature, the magnetic anisotropy improves as indicated by an increase of the average value of hyperfine magnetic field. However, magnetic moments turn out of the ribbon plane and this process continues towards higher production velocity, i.e., smaller thickness of the ribbons. No appreciable deviations in the investigated Mossbauer parameters were revealed after annealing during different time intervals.