The γ-Fe4N system revisited:: an ab initio calculation study of the magnetic interactions

We report results of an ab initio investigation of the magnetic properties of gamma-Fe4N. It is found that the magnetic moments are at the Slater-Pauling limit (2.7 mu(B)) and in a low moment state (similar to 1.6 mu(B)) for the two iron positions, respectively. This latter state is compared to the low moment state found for FCC-iron and the basically different behaviour of the two iron positions is discussed in terms of chemical pressure exerted by the nitrogen atoms. We also report about the pressure dependence of the magnetic moments, the hyperfine fields, the isomer shifts and the electric field gradient on the two iron sites. (C) 1999 Elsevier Science B.V. All rights reserved.