Magnetic Nanoparticles of Iron Carbide, Iron Oxide, Iron@Iron Oxide, and Metal Iron Synthesized by Laser Ablation in Organic Solvents

Abstract

Iron-based nanoparticles can have useful magnetic and catalytic properties. We investigated the synthesis of iron-based nanostructures by laser ablation of bulk iron with 1064 nm nanosecond pulses in the following organic solvents: tetrahydrofuran, acetonitrile, dimethylformamide, dimethylsulfoxide, toluene, and ethanol. Structural analysis carried out by transmission electron microscopy and X-ray diffraction revealed that the solvent has a dramatic influence on both the composition and the nanostructure of nanoparticles. Various magnetic nanoparticles like iron carbide (Fe3C), magnetic iron oxide (magnetite/maghemite), metal iron (α-Fe), and iron@iron oxide are obtained by varying the solvent and keeping unchanged all the other experimental conditions. These results are the consequences of the different reactivity of solvent molecules exposed to the plasma plume generated during the ablation process.