MOSSBAUER-SPECTRA AND MAGNETIC-PROPERTIES OF IRON NITRIDES

The iron nitrides Fe3N, Fe4N and Fe8N (impure) have been prepared by t reating iron in NH3/H-2 gas mixtures followed by appropriate heat trea tment. Fe8N has also been prepared by mechanical alloying. Mossbauer s pectra are analysed in terms of iron sites with different nitrogen env ironments, and results are compared with magnetization measurements an d band-structure calculations. Moments and hyperfine fields on sites w ith nitrogen neighbours are reduced by p-d hybridization, whereas the sites farthest from nitrogen have the lowest charge and the highest mo ments. There is no evidence of an exceptionally high magnetization in any of these compounds.