A Sn 119 Mössbauer study of RE 6M 13Sn (RE = La, Pr, Nd; M = Fe, Co) and their hydrides

¹¹⁹Sn and ⁵⁷Fe Mössbauer studies are reported for various RE₆Fe₁₃X compounds, isostructural La₆Co₁₃Sn, and some of their hydrides. The ¹¹⁹Sn studies prove that Sn exclusively occupies a single lattice site (4a). At 4.2 K a transferred magnetic hyperfine field of about 5 T is present which at room temperature is reduced to 2.5 T. This result clarifies the open questions concerning the ¹⁹⁷Au spectra from Pr(Nd)₆Fe₁₃Au and justifies the conclusions drawn earlier that this pattern is due to a magnetic hyperfine interaction. Spectra of hydrides indicate that the transferred hyperfine field on the Sn site is little affected by the uptake of hydrogen, unlike the ⁵⁷Fe hyperfine field. From the ⁵⁷Fe results an information is gained about the Fe site occupation and the specific easy axis of magnetization in a given sample. Comparing magnetization and hyperfine field data as a function of temperature, a complex spin structure in the majority of the compounds under investigation is suggested.