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MA: Fachverband Magnetismus
MA 14: Bio- and Molecular Magnetism
MA 14.1: Talk
Tuesday, April 1, 2014, 09:30–09:45, HSZ 401
Magnetic Coupling of Gd3N@C80 Endohedral Fullerenes to a Substrate — Christian F. Hermanns1, •Matthias Bernien1, Alex Krüger1, Christian Schmidt1, Sören T. Waßerroth1, Gelavizh Ahmadi1, Benjamin W. Heinrich1, Martin Schneider2, Piet W. Brouwer2, Katharina J. Franke1, Eugen Weschke3, and Wolfgang Kuch1 — 1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin — 2Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin — 3Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin
Using magnetic endohedral fullerenes for molecular spintronics requires control over their encapsulated magnetic moments. We show by field-dependent x-ray magnetic circular dichroism measurements of Gd3N@C80 endohedral fullerenes adsorbed on a Cu surface that the magnetic moments of the encapsulated Gd atoms lie in a 4f7 ground state and couple ferromagnetically to each other. When the molecules are in contact with a ferromagnetic Ni substrate, we detect two different Gd species. The more abundant one couples antiferromagnetically to the Ni magnetization, whereas the other one exhibits a stronger and ferromagnetic coupling to the substrate. Both of these couplings to the substrate can be explained by an indirect exchange mechanism mediated by the carbon cage. The origin of the distinctly different behavior may be attributed to different orientations and thus electronic coupling of the carbon cage to the substrate.
Financial support by the DFG (Sfb 658) is gratefully acknowledged.