NITROGEN-INDUCED AND CARBON-INDUCED REDUCTION OF GD-FE EXCHANGE COUPLING IN GD2FE17 DOPED SAMPLES

Inelastic neutron scattering (INS) is an important experimental method for determining intrinsic magnetic parameters of magnetic materials. For the new hard magnets containing rare earth R and transition metal T ions these microscopic parameters describe for example the exchange and crystal field interactions. We: have employed the INS method to determine with very good accuracy the intersublattice exchange coupling between the R=Gd and T=Fe sublattices in Gd2Fe17, Gd2Fe17N2, and Gd2Fe17Cx with x=0.5, 1.0 and 1.5. Although it is well known that the overall magnetic properties of N- and C-doped samples are considerably better than those of the pure compound Gd2Fe17 we find a drastic reduction in the Gd-Fe exchange coupling in the doped samples.