Double coordinence du fer dans la phase Fe xZrSe 2 (0 < x < 0,25): propriétés magnétiques et caractéristiques Mössbauer
The Fe xZrSe 2 compounds have been studied from the structural, magnetic, and Mössbauer points of view. The structure of a Fe 0.18ZrSe 2 single crystal has been refined to a final 0.067 R factor value. Iron disorderly occupies both octahedral and tetrahedral voids of the Van der Waals gap of ZrSe 2. The Curie constants are consistent with the Fe(II) state. Negative θp show that interactions are predominantly A.F. For x < 0.18, χ-1 tends toward zero with temperature. For x ≥ 0.18, a susceptibility maximum occurs for T ⋍ 7 K. Mössbauer spectra have been fitted considering two components: a singlet (tetrahedral Fe II) and a doublet octahedral Fe II) broadened by the □-Fe disorder. The Mössbauer parameters and their thermal evolution are discussed.