Abstract
Superparamagnetic iron oxide nanoparticles (SPIONs) have been successfully synthesized through a simple and facile hydrothermal reduction route using a single iron precursor (FeCl3 center dot 6H(2)O), and a combination of the inherent chemical reduction capability of maltose decomposition products (glucose as a reducing sugar) and its acid (gluconic acid as a capping agent). Magnetization measurements indicate that the Fe3O4 nanoparticles are superparamagnetic at room temperature and ferromagnetic at low temperatures. From zero-field cooled and field cooled magnetization measurements, the blocking temperature (T-B) of the Fe3O4 nanoparticles was determined as being 74 K. The lower reduced remanent magnetization (M-r/M-s) values than the theoretical value of 0.5 showed that the Fe3O4 nanoparticles have uniaxial anisotropy, according to the Stoner-Wohlfarth model. The effective magnetic anisotropy constant (K-eff) is calculated to be about 0.49 x 10(6) erg/cm(3), which is higher than that of bulk Fe3O4. The observed negligible coercivity and remanence magnetization demonstrated that the Fe3O4 NPs synthesized by the green method in this study have superparamagnetic behaviour at room temperature. They display potential applications in biomedicine. (C) 2013 Elsevier Ltd. All rights reserved.