Magnetic iron oxide nanopowders produced by CO2 laser evaporation-'In situ' coating and particle embedding in a ceramic matrix

The CO2 laser evaporation technique is not only well suited for the production of magnetic iron oxide nanopowders, but also allows for their conditioning. Two optional methods, the 'in situ' coating and the co-laser evaporation, are introduced. Laser-generated magnetic FexOy nanoparticles very frequently form chain-like structures, which were stabilized by 'in situ' coating with stearic acid. A first attempt was made to align these chains in a magnet field before the coating process. Homogeneous hematite/silica mixtures were co-laser evaporated in order to embed FexOy nanoparticles in a silica matrix. The produced nanopowders were analyzed with TEM, X-ray diffraction (XRD), and magnetic measurements. (C) 2009 Elsevier B.V. All rights reserved.