Preparation of magnetic nanoparticles and their assemblies using a new Fe(II) alkoxide precursor

Hydrolysis of the new metallorganic precursor Fe(OBut)(2)( THF)(2) followed by ultrasound and thermal treatment yielded either nanoparticles of gamma -Fe2O3 or Fe3O4, depending on the process conditions. The samples have been characterised by X-ray powder diffraction, TEM, SEM, Mossbauer spectroscopy and magnetization measurements. The maghemite nanoparticles (9 +/- 2 nm) are superparamagnetic and form unique needle-like assemblies of nanoparticle arrays. The nanoparticles of Fe3O4 (19 +/- 2 nm) form plate-like aggregates about 10 mum thick.