Hyperfine interactions on iron in R2−xFe14 + 2xSi3 (R = Ce, Nd, Gd, Dy, Ho, Er, Lu, Y) compounds studied by Mössbauer spectroscopy

Compounds R2−xFe14 + 2xSi3 with (R = Ce, Nd, Gd, Dy, Ho, Er, Lu, Y) were prepared by the modified Czochralski method and investigated by means of the 57Fe 14.4 keV Mössbauer spectroscopy and powder X-ray diffraction. The magnetic moment was additionally measured for samples being single crystals. Iron experiencing low magnetic hyperfine field and electric quadrupole interaction was found on (4e) sites in the P63/mmc structure. Similar iron was found in the R3¯m structure as well. The non-stoichiometry parameter was determined as being close to 2x = 0.5 for all compounds investigated. Compound with R = Ho crystallizes in both structures. Our results show that silicon avoids (4f) and (6g) sites for compounds with the P63/mmc structure (R = Dy, Ho, Er, Lu, Y), whereas it avoids (6c) and (9d) sites for those with R3¯m structure (R = Nd, Gd, Ho).