Synthesis and Characterization of Magnetic Nanoalloys from Bimetallic Carbonyl Clusters

Abstract

Magnetic nanoparticles are potentially useful for biomedical research because of their unique chemical and physical properties. In particular, magnetic alloy nanoparticles are of interest because of their magnetic properties and chemical stability. However, controlling the composition of magnetic alloy nanoparticles can be difficult when they are produced from two or more precursors. This could be overcome by using a single precursor of bimetallic carbonyl cluster in a thermal decomposition process. We have used this novel synthesis method to produce FeCo3, FeNi4, FePt, and Fe4Pt alloy magnetic nanoparticles, with average diameters of 7.0, 4.4, 2.6, and 3.2 nm. The chemical and physical properties of the synthesized nanoparticles were examined by elemental analysis, transmission electron microscopy, powder X-ray diffractometry, and SQUID magnetometry. The chemical composition of the synthesized nanoparticles reflected that of the bimetallic carbonyl cluster used for their synthesis. Different reaction conditions, such as ligand concentration, ligand type, and reaction temperature had very little effect upon the chemical and physical properties of the synthesized nanoparticles. This work represents a versatile method for the synthesis of magnetic alloy nanoparticles and can be applied to a variety of other elements.