Synthesis and characterization of iron/iron oxide core/shell nanocubes

Abstract

A simple method for the preparation of iron/iron oxide nanoparticles with core/shell cubic morphology is presented. The synthesis of the nanocubes was carried out through decomposition of a preformed iron oléate complex at high temperature. Although this procedure has been shown previously to produce monodisperse magnetite spheres,[1] the use of squalene as a solvent and the presence of sodium oleate was found to induce cube formation. A detailed high-resolution transmission electron microscopy (HRTEM) analysis of the nanocubes was performed for structural characterization. The core/shell structure, an iron core surrounded by magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) filtering analysis. The results obtained by HRTEM analysis are in agreement with X-ray Photoelectron Spectroscopy (XFS) and magnetic analysis. The Fc nanocubes are superparamagnetic at room temperature with a saturation magnetization Ms = 101 A m2 kg-1 and magnetic anisotropy density Keff = 1.6 × 105 J m-3 at low temperatures. © 2007 WILEY-VCH Verlag GmbH & Co. KCaA.