Thickness Dependence of Mössbauer Parameters for Fe₇₈Si₉B₁₃ Metallic Glass Ribbons

Changes in magnetic microstructure of Fe₇₈Si₉B₁₃ ribbons were investigated by the Mössbauer 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 Mössbauer 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 Mössbauer parameters were revealed after annealing during different time intervals.