Synthesis and characterization of CoO, Co3O4, and mixed Co/CoO nanoparticules

Marc Verelst, Teyeb Ould Ely, Catherine Amiens, Etienne Snoeck, Pierre Lecante, Alain Mosset, Marc Respaud, Jean Marc Broto, Bruno Chaudret

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Abstract

Very small nanometric oxide particles (CoO and Co3C4, around 2 nm in diameter) well dispersed inside a polymer matrix were prepared by solid-state oxidation of a metallic colloid precursor (1.6 nm Co particles). WAXS (wide-angle X-ray scattering) and HREM (high-resolution electronic microscopy) were used to observe very precisely the structural changes occurring during the oxidation process. With cobalt particles a few nanometers large, air oxidation at room temperature results in a surface passivation. Consequently the particles show a composite structure with a metallic core surrounded by an oxide surface layer. Preliminary magnetic measurements reveal that unidirectional exchange anisotropy between the metallic ferromagnetic core and the antiferromagnetic oxide layer occurs below 130 K.

Original languageEnglish
Pages (from-to)2702-2708
Number of pages7
JournalChemistry of Materials
Volume11
Issue number10
Publication statusPublished - Dec 1 1999

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ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Verelst, M., Ely, T. O., Amiens, C., Snoeck, E., Lecante, P., Mosset, A., Respaud, M., Broto, J. M., & Chaudret, B. (1999). Synthesis and characterization of CoO, Co3O4, and mixed Co/CoO nanoparticules. Chemistry of Materials, 11(10), 2702-2708.