⁵⁷Fe M\ddot\rm OSSBAUER STUDY ON (NdDy)TiFe₁₁N_y COMPOUNDS

⁵⁷Fe M\ddotossbauer spectra have been obtained at room temperature for (NdDy)TiFe₁₁, and at 11 K and room temperature for the corresponding nitrides (NdDy)TiFe₁₁N_y. The magnetic behaviors of Fe atoms at different sites have been studied. We have found a larger increase of the hyperfine fields upon nitrogenation due to the higher nitrogen content in these compounds and got a bigger enhancement of the isomer shift in 8j site because of the nearest nitrogen environment.