Structural, magnetic, and Mossbauer characterization of size-controlled iron-iron oxide nanoparticles obtained by chemical methods

Size-controlled Fe nanoparticles have been obtained by thermal decomposition of Fe(CO)/sub 5/ in organic solution, in the presence of ligand molecules. Samples with different sizes, in the 6-12 nm range have been characterized by high-resolution transmission electron microscopy, X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. All samples present narrow size distributions and superparamagnetic behavior. The exposition to air leads to the formation of a polycrystalline phase, mainly Fe/sub 3/O/sub 4/.