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

Hydrolysis of the new metallorganic precursor Fe(OBu^t)₂-(THF)₂ followed by ultrasound and thermal treatment yielded either nanoparticles of γ-Fe₂O₃ or Fe₃O₄, depending on the process conditions. The samples have been characterised by X-ray powder diffraction, TEM, SEM, Mössbauer 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 μm thick.