A SN-119 MOSSBAUER STUDY OF RE6M13SN (RE=LA, PR, ND, M=FE, CO) AND THEIR HYDRIDES

Sn-119 and Fe-57 Mossbauer studies are reported for various RE6Fe13X c ompounds, isostructural La6Co13Sn, and some of their hydrides. The Sn- 119 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 p resent which at room temperature is reduced to 2.5 T. This result clar ifies the open questions concerning the Au-197 spectra from Pr(Nd)(6)F e13Au 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 affecte d by the uptake of hydrogen, unlike the Fe-57 hyperfine field. From th e Fe-57 results an information is gained about the Fe site occupation and the specific easy axis of magnetization in a given sample. Compari ng magnetization and hyperfine field data as a function of temperature , a complex spin structure in the majority of the compounds under inve stigation is suggested.