Hyperfine interactions in Y2Fe17

Mössbauer measurements are performed on rhombohedral Y2F17 in the temperature range 5 to 300 K and in fields up to 20 kOe. The dipole fields and the crystalline electric field gradients are calculated for both structure types. From this a subdivision of the four crystallographically non-equivalent lattice sites into seven (eight) groups for the Th2Zn17 (Th2Ni17) compounds is concluded, by neglecting all contributions of the asymmetry parameter. An exact allocation of the resulting subspectra to these different Fe sites is only possible for the c (f)- and a fraction of the d (g)-sites. The field and the temperature dependence of the hyperfine interactions of the distinguishable Fe sites are discussed.