Mössbauer Study of Hyperfine Fields and Isomer Shifts in Fe 4 N and ( F e , N i ) 4 N

Authors(s):G. Shirane, W. J. Takei, and S. L. Ruby Publication:Physical Review Publication Date:April 1, 1962 Publisher: American Physical Society Citation:Phys. Rev. 126, 49 Link:https://doi.org/10.1103/PhysRev.126.49

Mössbauer measurements of Fe57 were made on ferromagnetic Fe4N, which has a face-centered cubic arrangement of iron atoms with nitrogen at the body-center position. The hyperfine fields are 345 koe for the corner Fe and 215 koe for the three face-center Fe, approximately proportional to their magnetic moments, 3μB and 2μB. The isomer shifts, measured against a stainless steel source, are 0.30 mm/sec for the corner Fe and 0.45 mm/sec for the face-center Fe. These values are in line with their proposed electronic configurations of 3d74s and 3d84s, which are derived on the assumption that the nitrogen at the body-center position acts as an electron "donor" to the face-center Fe. The Mössbauer spectra of (Fe3.6,Ni0.4)N and (Fe3Ni)N are consistent with their ordered structures in which Ni replaces the corner Fe preferentially.