Abstract

Iron oxide nanoparticles were synthesized by employing an ultrasonic homogenizer in conjunction to the co-precipitation of Fe(NO<inf>3</inf>)<inf>3</inf>·9H<inf>2</inf>O, FeCl<inf>2</inf>·4H<inf>2</inf>O and NaOH. Synchrotron X-ray absorption near edge structure (XANES) spectra could be fitted with the contributions from hematite (α-Fe<inf>2</inf>O<inf>3</inf>) and, to a lesser extent, metallic Fe. The increase in reagent concentrations increased the Fe fraction which partly explained the change in magnetization of superparamagnetic particles. Nevertheless, the α-Fe<inf>2</inf>O<inf>3</inf> composition was increased by using a longer reaction time. © (2014) Trans Tech Publications, Switzerland.