Synthesis and characterization of surfactant-coated superparamagnetic monodispersed iron oxide nanoparticles

Synthesis and coating of superparamagnetic monodispersed iron oxide nanoparticles was carried out by chemical solution method. Controlled co-precipitation technique was used to prevent undesirable critical oxidation of Fe2+. The obtained Fe3O4 nanoparticles were coated with sodium oleate. Low-held AC susceptibility and SQUID measurement show superparamagnetism with a blocking temperature around 150K, and almost immeasurable remanence and coercivity. (C) 2001 Elsevier Science B.V. All rights reserved.