Mossbauer, X-ray, magnetization and susceptibility measurements were p
erformed to study Fe100-xMnx, x = 5, 15, 39, 50. The different phases
of Fe-Mn were identified, and hyperfine interaction parameters and ave
rage magnetic moments of some samples were determined. The average hyp
erfine field and average magnetic moment decrease as x increases. The
influence of the Mn neighbourhood on the derived parameters is discuss
ed in the light of calculations using the first principle discrete var
iational method in the local density approximation.