The temperature dependence of the hyperfine interactions at¹¹⁹Sn in iron

Measurements of the hyperfine interactions at impurity 119 Sn nuclei in iron have been made at temperatures between 4.2K and 972K using Mossbauer spectroscopy. Both the hyperfine field and isomer shift measurements, when converted to constant volume, show unusual temperature dependences and it is deduced that these results imply a temperature dependence of the electronic structure in the vicinity of the impurity. Current models for the origin of the hyperfine field at tin and similar impurities in magnetic transition metals are reviewed, and used as a basis for this conclusion. The temperature dependence of the Mossbauer absorption was also measured, and indicates that the tin impurity ion vibrates as an isotopic impurity in the iron matrix.