Nitrogen location in R2Fe17 compounds: an NMR study

Abstract 14 N, 89 Y and 1 H spin-echo NMR experiments have been carried out in order to study the nitrogen location in the R 2 Fe 17 lattice with R = Gd, Lu and Y. The observed 14 N spectrum for the Gd-compound indicates that essentially all of the N atoms occupy the octahedral interstitial sites. However, the ‘two-peak’ 14 N spectra for the Y-compounds and, to a lesser degree the Lu-compound, indicate that some of the N atoms enter the tetrahedral interstitial sites in addition to the octahedral sites. A consideration of both 14 N and 89 Y spectra indicates that the probability for a N atom to enter a tetrahedral site in the Y 2 Fe 17 lattice is much smaller than that for octahedral site occupation. This study reveals that the local structure of Y 2 Fe 17 N x may change with the nitrogenation conditions.