Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 35: Poster Session II

MM 35.35: Poster

Mittwoch, 25. März 2009, 16:30–18:30, P4

Oxygen diffusion in an reaction rate of cobalt nanoparticles stabilized with different ligands — •Britta Vogel, Axel Dreyer, Nadine Mill, Anna Regtmeier, Inga Ennen, Daniel Ebke, Simone Herth, and Andreas Hütten — Department of Physics, University of Bielefeld, D-33615 Bielefeld, Germany

Cobalt nanoparticles with a diameter of 12nm have initially been prepared with TOPO. Subsequently a ligand exchange was carried out to employ different ligands to the nanoparticles while keeping direct comparability. The decrease of the magnetic moment of the nanoparticles corresponds directly to their oxydation. According to a model of Crank for irreversible reaction in a spherical particle the uptake of oxygen in the particles was analyzed. From the fit of the obtained data to the model, information about the diffusion of oxygen in cobalt and cobalt oxide as well as the oxidationrate is deduced. Additionally the temperature dependence is discussed.