Mossbauer spectroscopy applied to synthetic Fe9+xCu9-xS16

Synthetic compounds with the bulk composition Fe9+xCu9-xS16, x = 0, 0.2, 0. 4, 0.6 and 0.8, were studied with Mossbauer spectroscopy and powder XRD. Th e hyperfine parameters were determined in the temperature range 6-295 K. A model for local environments of iron is suggested. The Mossbauer spectra ha ve been described using a model of statistical distribution of Fe and Cu at oms among the interstitial sites in an antiferromagnetic structure similar to the one of chalcopyrite. The room-temperature Mossbauer spectra were res olved into four sextets and a component with a low magnetic held. The inten sity of the low-field component, which accounts for 30-40% of total Mossbau er absorption, was found to be independent of the composition of the sample but temperature sensitive. (C) 2000 Elsevier Science B.V. All rights reser ved.