Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.128: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Electronic structure and magnetism of No-dqFerric StarNo-dq molecule — •A. F. Takács¹, M. Neumann¹, M. Prinz¹, A. Postnikov², J. Kortus³, A. Scheurer⁴, S. Sperner⁴, and R. W. Saalfrank⁴ — ¹Universität Osnabrück, Fachbereich Physik, Barbarastr. 7, D-49069 Osnabrück, Germany — ²IFF F2 Jülich, D-52425 Jülich, Germany — ³IPCMS- GMI F -67037 Strasbourg -France — ⁴University of Erlangen-Nuernberg, 91054 Erlangen- Germany

The electronic structure of magnetic molecules of the type [M(FeL₂)₃]· 4CHCl₃ where M=Fe, Cr and L=H₃CN(CH₂CH₂O)₂²⁻ has been studied using X-ray photoelectron spectroscopy , soft X-ray emission spectroscopy as well as theoretical density-functional-based methods. Three peaks have been found in the valence band region by XPS, which are excellently reproduced by the calculated tDOS, also the partial DOS agrees very well with the XES results. The top of the valence band is dominated by the hybridization between M 3d and O 2p bands. The Fe core level spectra indicate that Fe is in the Fe²⁺ state, which is in a good agreement with the calculated magnetic moment of ≈ 4µ_B. The neighbouring atoms primarily oxygen and nitrogen exhibit a magnetic polarisation yielding effective spin S=5/2 per iron atom. Due to antiparallel orientation of the magnetic moments of the central M ion relatively to three peripheric Fe, the total resulting spin per molecule in the ground state amounts to S=5 (M=Fe) or S=6 (M=Cr).