From nanocrystals to nanorods: New iron oxide-silica nanocomposites from metallorganic precursors

Sol-gel one-step processing of the Fe(II) alkoxide [Fe(OBUt)(2)(THF)](2) and tetraethyl orthosilicate (TEOS) at various ratios afforded new silica-iron oxide magnetic nanocomposite materials, ranging in shape from nanocrystals to nanorods depending on the percentage of TEOS added. The nanocomposites have been investigated by Fourier transform infrared and Raman spectroscopy, X-ray diffraction, Fe-57 Mossbauer spectroscopy, magnetization measurements, transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive X-ray analysis. These silica-coated magnetic materials might have a range of potential applications in biotechnology, medicine (e.g., as magnetic fluids for MRI), catalysis, and magnetic storage.