Fe-57 Mossbauer study of Pr-m(Fe, MO)(n) compounds with m : n=2 : 17 and 1: 12

The effects of Mo substitution in Pr2Fe17-xMox and PrFe12-xMox compounds we re investigated by X-ray diffraction, magnetic measurements and Mossbauer s pectroscopy. Different fitting procedures, using magnetic sextets at low te mperature, magnetic sextets and quadrupole doublets at room temperature and paramagnetic doublets well above the Curie points, had to be considered in order to analyze the Mossbauer spectra. The Mossbauer data obtained on the Mo-containing compounds stand for distributions of the hyperfine fields du e to the random distributions of Mo over the 6c sites in the 2:17 and 8i si tes in the 1:12 compounds. The variations in the isomer shifts and hyperfin e fields with composition are discussed in relationship to the local enviro nment details at the different iron sites. Site-specific information on the electronic effects due to Fe(Sd)-Mo(4d) states hybridization are derived. (C) 1999 Elsevier Science S.A. All rights reserved.