Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 33: Bio- Molecular Magnetism
MA 33.8: Vortrag
Donnerstag, 26. März 2009, 12:00–12:15, HSZ 103
Anisotropy and frustration of the high-spin
[CrIIIMn3II(PyA)6Cl3] molecule — •Manuel Prinz1, Michael Raekers1, Karsten Kuepper2, Marc Uhlarz2, Sumit Khanra3, Biplab Biswas3, Thomas Weyhermüller3, Jürgen Schnack4, and Manfred Neumann1 — 1University of Osnabrück, Fachbereich Physik, D-49069 Osnabrück — 2Forschungszentrum Dresden-Rossendorf, POB 51 01 19, D-01314 Dresden — 3MPI für Bioanorganische Chemie, D-45470 Mülheim an der Ruhr — 4Universität Bielefeld, Fakultät für Physik, D-33501 Bielefeld
Molecular magnets incorporate transition metal ions with organic groups providing a bridge to mediate magnetic exchange interactions between the ions. There are star-shaped molecules in which antiferromagnetic couplings between the central and peripheric atoms is predominantly present. Those configurations lead to an appreciable spin moment in the non-frustrated ground state. In spite of its topologically simple magnetic system, the [CrIIIMn3II(PyA)6Cl3] (CrMn3) molecule exhibits non-trivial magnetic properties, like anisotropy and frustration. In the present work we elucidate the underlying magnetic properties of the hetero nuclear, spin-frustrated CrMn3 molecule applying high magnetic field measurements, X-ray magnetic circular dichroism (XMCD), anisotropic Heisenberg simulations and classical spin dynamic methods. Modeling the high field data by anisotropic Heisenberg simulations and dicussion of the various spin Hamiltonian parameters leads to a validation of our element selective transition metal XMCD spin moments at a magnetic field of 5 T and a temperature of 5 K.