Synthesis and Characterization of Iron/Iron Oxide Core/Shell Nanocubes


  • This work was supported by the European Community's Marie-Curie Research Training Network “SyntOrbMag” (contract No. MRTN-CT-2004-005567) and the Spanish Ministerio de Educación y Ciencia through the project “Nanobiomed (CONSOLIDER-INGENIO 2010)”. The authors are thankful to Dr. Carmen Serra for performing XPS measurements. Supporting Information is available online from Wiley InterScience or from the author.


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 oleate 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 (XPS) and magnetic analysis. The Fe 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.