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O: Fachverband Oberflächenphysik
O 22: Surface or Interface Magnetism
O 22.2: Talk
Tuesday, March 27, 2007, 11:30–11:45, H36
Electronic structure and magnetic properties of two-dimensional metal-organic coordination structures at a metal surface — •Sebastian Stepanow1,2, Alexandre Dmitriev2, Subhra Sen Gupta3, Jan Honolka2, Sylvain Clair4, Stephane Pons4, Magali Lingenfelder2, Peter Bencock5, Dipankar Das Sarma3, Nian Lin2, Harald Brune4, Johannes Valentin Barth6, Klaus Kern2,4, and Pietro Gambardella1,7 — 1ICN, Barcelona — 2MPI-FKF, Stuttgart — 3IIoS, Bangalore — 4EPFL, Lausanne — 5ESRF, Grenoble — 6UBC, Vancouver — 7ICREA, Barcelona
Recently various 2D metal-coordination structures at a Cu(100) surface have been synthesized. The arrays contain mono- and dinuclear Fe ions embedded in defined ligand-field environments tunable by the employed organic ligand molecules and further manipulated by adsorbed gas molecules. Polarized x-ray absorption spectroscopy was used to investigate the electronic structure and magnetic properties of the metal ions. The results demonstrate that the properties of the Fe centers are mainly determined by the strong coordination bonds to the ligands which drive the effective dehybridization of the Fe atoms from the surface. In-plane and out-of-plane magnetic anisotropy orientations as well as isotropic compounds can be obtained. The temperature dependence of the magnetic anisotropy and related orbital magnetization indicate the thermally excited molecular states present different magnetic properties compared to the ground state. XMCD spectra are discussed in the framework of a simple atomic multiplet theory considering the influence of the crystal-field and spin-orbit coupling on the Fe 5D term.