Face-Centered-Cubic “Supracrystals” of Cobalt Nanocrystals


  • Thanks are due to Dr. A. T. Ngo from our laboratory for SEM images. We also thank D. A. Loiseau of ONERA (Châtillon) for providing us with facilities for using the transmission electron microscope.


Magnetic “supra” crystals have been built by slow evaporation of a solution of 7.2 nm cobalt nanoparticles in hexane. Scanning electron microscopy shows isolated pavements which height is of the order of 5 μm (see Figure). Investigation made by small-angle X-ray diffraction clearly indicates a face-centered cubic structure.