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MA: Fachverband Magnetismus

MA 3: Bio- and Molecular Magnetism

MA 3.7: Talk

Monday, March 14, 2011, 12:30–12:45, HSZ 401

Magnetic ground state of TM-Ni binuclear complexes studied by of x-ray circular magnetic dichroism and density functional theory — •Karsten Kuepper¹, Ulf Wiedwald¹, David M. Benoit², Florian Mögele³, Bernhard Rieger⁴, and Paul Ziemann¹ — ¹Institut für Festkörperphysik, Universität Ulm, Albert-Einstein-Allee 11, D-89081 Ulm — ²Nachwuchsgruppe Theorie im SFB 569, Universität Ulm, Albert-Einstein-Allee 11, D-89081 Ulm — ³Institut für Materialien und Katalyse, Universität Ulm, Albert-Einstein-Allee 11, D-89081 Ulm — ⁴WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching bei München

We investigate three planar TM-Ni-C₄₆H₆₈N₂O₆ (TM=Mn,Fe,Co) molecules [1] by low temperature XMCD revealing in this way the presence of uncompensated magnetic moments. The experiments have been performed at a temperature of 0.6K in order to probe the magnetic ground state properties. Theoretically, we address the energetic ordering of the different possible spin states of the bi-nuclear complexes using (zero-order) relativistic approximation density functional calculations and a triple-zeta quality basis set. These results show that medium-spin states are often favored over low-spin states for most metal combination, in qualitative agreement with our experimental observations.

[1] Florian Mögele et al., Langmuir 25, 13606 (2009).