Mossbauer study on local atomic structure in Fe80-xNbxB20 (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 nonequivalent 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