Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 14: Bio- and Molecular Magnetism
MA 14.3: Vortrag
Dienstag, 1. April 2014, 10:00–10:15, HSZ 401
FePc on Co(001): Influence of surface oxidation on structure, magnetism, and exchange coupling — •Heike C. Herper1, Barbara Brena1, Sumanta Bhandary1, David Klar2, Heiko Wende2, Biplab Sanyal1, and Olle Eriksson1 — 1Department of Physics and Astronomy, Uppsala University, Sweden — 2Fakultät für Physik und CeNIDE, Universität Duisburg-Essen, Germany
We present a density functional theory study combined with x-ray absorption spectroscopy measurements of the electronic and magnetic properties of Fe phthalocyanine (FePc) molecules on fcc Co(001) and c(2×2)O/Co(001). On the bare Co substrate one adsorption site is clearly preferred whereas the oxygen adlayer screens the molecule-substrate interaction and the energy differences between different adsorptions sites become smaller. Moreover the coupling between the Fe center and the Co surface switches from ferromagnetic to antiferromagnetic and the coupling strength is reduced due to the O layer. [1] Notably the coupling mechanisms also differ. On the Co(001) substrate a mixture of direct coupling between Fe and Co and an indirect coupling via the benzene rings is obtained from the DFT calculations whereas on the oxidized surface, an 180∘ coupling between Fe and Co via O dominates. Despite the changes in adsorption site and coupling, the spin state of the molecule is S=1 on both substrates.
[1] D. Klar et al., submitted to PRB