Mössbauer Study on Local Atomic Structure in $Fe_{80-x}Nb_xB_{20}$ (x=4, 6) Metallic Glasses

Fe-based amorphous alloys were prepared by the melt-spinning technique and characterized by X-ray diffraction and transmission Mössbauer spectroscopy. The studies were performed on Fe₇₆Nb₄B₂₀ and Fe₇₄Nb₆B₂₀ metallic glasses in the form of ribbons. The Mössbauer spectroscopy allows to study the local environments of the Fe atoms in the glassy state, showing the changes in the amorphous structure due to the changing of Nb addition. The obtained Mössbauer spectra of ferromagnetic metallic glasses present broad lines resulting from the distribution of non-equivalent iron sites and of interatomic distances. Variation of Nb content in the alloys affects the disorder in as-cast state and also influences on the average radius of the first coordination shell and the number of nearest neighbor Fe atoms.