Mössbauer study of amorphous Fe-Sb alloys with large composition range

Amorphous Fe_x Sb_100-x alloys with large composition range of 3<-x<-80 have been investigated with⁵⁷Fe Mössbauer spectroscopy. The concentration dependence of quadrupole splitting and its distribution reveal a similar atomic packing scheme in the range of 3<-x<-50. Significantly, the quadrupole splitting of crystalline FeSb₂ is larger than that of amorphous FeSb₂ by a factor of 3. The isomer shifts have been analyzed based on the Miedema-van der Woude's model of isomer shift. The distribution of magnetic hyperfine field P(H) indicates that the alloys are rather magnetically inhomogeneous around x=55.