Surface oxidation control of nanosized magnetite and Mössbauer measurements

Selected highly homogeneous powders of Fe3O4 with different particle size on the nanometer scale (10 ± 2 and 3 ± 2 nm) obtained by soft-chemical methods were studied by Mössbauer spectroscopy. The study shows clearly the powerful possibilities of Mössbauer spectroscopy to analyze the surface oxidation of nanostructured powders of magnetite. On the other hand, it is shown that for very small superparamagnetic particles the spectrum of magnetite might be quite similar to that of maghemite, making it difficult to distinguish between both phases.