Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 83: [MA] Focussed Session "X-ray absorption spectra - state of the art of theory and experiment" (jointly with DS, HL, MM, O)
O 83.4: Topical Talk
Donnerstag, 17. März 2011, 17:00–17:30, HSZ 403
Paramagnetic molecules on metal surfaces: prototypes for spin-hybrid systems — •Heiko Wende — Faculty of Physics and CeNIDE, University of Duisburg-Essen, 47048 Duisburg, Germany
The fundamental understanding of the interaction of paramagnetic molecules with metal surfaces is crucial for the possible application of these spin-hybrid systems in molecular spintronics. We study the magnetic properties of Fe-porphyrin and Fe-phthalocyanine molecules with sub-monolayer coverages on Ni and Co films on Cu(100) with and without an intermediate layer of atomic oxygen. Dichroism in X-ray absorption spectra (XNLD and XMCD) at the respective absorption edges (Fe, Co and Ni L2,3-edges, N and C K-edges) is investigated to identify the coupling of the molecules to the ferromagnetic layers, the orientation on the surfaces and the electronic structure. To determine the magnetic anisotropy of Fe- and Co-porphyrin molecules, the molecules were adsorbed on a non-magnetic substrate (Cu(100)). Therefore, angular-dependent XAS and XMCD spectra were measured at 5T and 8K. Calculated XAS spectra obtained from DFT and multiplet calculations using ligand field theory enable a solid interpretation of the experimental data. This work is done in collaboration with C. Weis, D. Klar, D. Bovenschen, M. Kaya, H.C. Herper, B. Krumme, A. Warland, C. Antoniak (Univ. Duisburg-Essen), M. Bernien, J. Miguel, M. Piantek, K. Baberschke, W. Kuch (FU Berlin), P. Srivastava (IIT Delhi), and B. Brena, Md. E. Ali, P.M. Panchmatia, P.M. Oppeneer, B. Sanyal, O. Eriksson (Uppsala Univ.). Supported by BMBF (05 ES3XBA/5), DFG (SFB 491 and SFB 658), STINT and ESRF(HE2700).