INFLUENCE OF NEIGHBOURING CHROMIUM ATOMS ON HYPERFINE FIELDS AT 57Fe NUCLEI AND ISOMER SHIFTS IN Fe-Cr ALLOYS

S. Dubiel , K. Krop

Using several different models it has been shown, that among the two-shell models employed for fitting the Mössbauer spectra of Fe-Cr alloys the most adequate is the one, which includes only contributions from those Cr atoms which occupy the first two coordination spheres. Employing then this model for fitting the Mössbauer spectra of Fe-Cr alloys having different chromium concentration (1-15 at % Cr) it has been revealed, that the change of the hyperfine magnetic field at 57Fe nuclei, ƊH1, due to an impurity atom in the first coordination sphere is higher than the change, ƊH2, due to a second-nearest neighbour impurity. The ratio R = ƊH1/ƊH2 turns out to be concentration dependent and least-squeres fits to Our data show that it may be expressed as R = 1.24 + 0.03 c for the M 12-model or R = 1.24 + 0.02 c for the M 12 BW-model. The problem of the additivity of the observed effects of Cr atoms both on the hyperfine magnetic fields at 57Fe nuclei and on the isomer shifts was also investigated. For the hmf partial and total additivity is observed, whilst for the IS only total additivity occurs within rather high experimental errors.

Domaines: Articles anciens

S. Dubiel, K. Krop. INFLUENCE OF NEIGHBOURING CHROMIUM ATOMS ON HYPERFINE FIELDS AT 57Fe NUCLEI AND ISOMER SHIFTS IN Fe-Cr ALLOYS. Journal de Physique Colloques, 1974, 35 (C6), pp.C6-459-C6-464. ⟨10.1051/jphyscol:1974695⟩. ⟨jpa-00215852⟩