A study of dilute Fe-Os alloys by 57Fe Mössbauer spectroscopy

The room temperature Mössbauer spectra of 57Fe were measured for a Fe1−xOsx alloys where x is in the range between 0.01 and 0.20. Analysis of the obtained spectra gave unique information about hyperfine field and isomer shift changes caused by presence of osmium impurities in the two first coordination shells of the iron atom. Moreover, the Mössbauer data were used to determine values of the short-range order parameter and the pair-wise interaction energy with the help of a quasi-chemical type formulation introduced by Cohen and Fine. The obtained results reveal that for well annealed Fe-Os alloy one observes strong clustering-type correlations (a predominance of Fe-Fe and Os-Os bonds).