Dresden 2009 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)

MA 40.59: Poster

Freitag, 27. März 2009, 11:00–14:00, P1A

Investigation of the magnetic configuration of LuFe₂O₄ by means of XMCD and multiplet calculations — •Christine Derks¹, Michael Raekers¹, Christian Taubitz¹, Karsten Kuepper², Stephen J. Blundell³, Dharmalingam Prabhakaran³, and Manfred Neumann¹ — ¹Universität Osnabrück, FB Physik, Osnabrück — ²FZ Dresden-Rossendorf, Dresden — ³Clarendon Laboratory, University of Oxford, Oxford, UK

The use of magneto electric coupling and multi ferroics in spintronics has led to an intense research of ferro electric magnets. The spinel LuFe₂O₄ is a very promising candidate for such applications. This compound exhibits giant room temperature magneto dielectric response, which suggests a strong coupling between spin moment und electric dipole. The resulting giant magneto capacitance is due to charge ordering of mixed valent iron ions. A complex two dimensional ferri magnetism plays an important role for the multi ferroic properties of LuFe₂O₄. We determine the magnetic configuration by means of XMCD. Experimental data are compared with multiplet calculations, which are performed with the TT multiplet program [1]. The trigonal bipyramidal crystal symmetry was included in these calculations. We suggest a local charge order with a ferrimagnetic structure as found by Mössbauer and neutron diffraction; The minority spin sub lattice exhibits 2/3 of total Fe³⁺ ions whereas the majority spin subband contains 1/3 of Fe³⁺ and all the Fe²⁺ ions. [1] F.M.F. de Groot, High resolution x-ray emission and x-ray absorption spectroscopy, Chem. Rev., vol. 101, pp. 1779-1808, (2001).