Mössbauer-Effect Studies of Iron-Tin Alloys

Solid solutions $\mathrm{Fe}\mathrm{Sn}$ and the compounds ${\mathrm{Fe}}_3$Sn, ${\mathrm{Fe}}_5$ ${\mathrm{Sn}}_3$, ${\mathrm{Fe}}_3$ ${\mathrm{Sn}}_2$, FeSn, and Fe${\mathrm{Sn}}_2$ have been studied by the Mössabauer effect in both Fe and Sn nuclei. Also, standard x-ray diffraction and magnetization studies were performed. The magnetic hyperfine (hf) fields in the Fe and Sn components are not, in general, proportional to the magnetic moments. It is found that two simple relations containing the coordination numbers can be used within a wide range to describe the variations of these fields as a function of composition. The collected results indicate that the magnetic hf field at the iron nucleus is rather insensitive to the conduction-electron polarization in these alloys. The isomer shifts are linearly related to the number of Fe-Sn bonds in such a way that bonding reduces the electron densities at both nuclei. The bonding is covalentlike and predominantly unpolarized.