Synthesis of carbon-encapsulated magnetic nanoparticles by pulsed laser irradiation of solution

A method for synthesizing carbon-encapsulated magnetic nanoparticles (CEMNPs) is reported. In the proposed method, a solution containing various metalocenes dissolved in xylene is irradiated with a nanosecond pulsed ultraviolet laser at room temperature and atmospheric pressure. Upon the completion of irradiation, CEMNPs (Fe–C, Ni–C, Co–C) with diameters ranging from a few nanometers to about 300 nm are produced in the solution. The material characteristics of these nanoparticles are then examined with electron microscopy, Raman spectroscopy, X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometry. It was found that the magnetic nanoparticles coated with graphitic shells exhibit good stability in a high concentration HCl (10 mol) solution. The possible growth mechanisms of CEMNPs under the pulsed laser irradiation of the solution are then discussed.