Crystallographic and magnetic structures of Fe7Se8 at low temperature (4–78 K)

Mössbauer spectra of ferrimagnetic Fe7Se8 prepared with 57enriched iron have been taken at 298 K and below 78 K on a “3c” absorber. Three sets of six-line hyperfine patterns were obtained and assigned to three magnetically nonequivalent sites of a superstructure of the crystal. It is shown that the results obtained at the low-temperature region are well consistent with Okazaki’s [A. Okazaki and K. Hirakawa, J. Phys. Soc. Jpn. 11, 930 (1956).] “3c” superstructure model.