Inorganic Chemistry, University of Cologne

  • Sanjay Mathur, Lisong Xiao, Thomas Lehnen, Gregor Fornalczyk, Laura Wortmann
    Theme: Determining the magnetic properties of nano-particles e.g. SiO2 coated superparamagnetic Fe3O4 and Fe2O3, wires of FeVO4. The former materials are supposed to be used as contrast substance for magneto-resonance-imaging (MRI) in medical treatments.

    Aadesh P. Singh, Andreas Mettenbörger
    Theme: The exact reduction level of Fe2O3 into Fe3O4 and TiO2 into Ti2O3 in thin films should be determined. This is crucial when trying to optimize the size of the optical band gap so that solar energy can be used to split water into hydrogen and oxygen and at the same time use as much as possible of the solar spectrum. These materials are supposed to be used as solar cells in the future.

    Axel Klein, Alexander Krest, Irina Giebelhaus
    Theme: Magnetic investigations of transition metal ions in several different chemical environments, including Jahr-Teller distortions and optical properties. This belongs to fundamental research.

    II. Physics Department, University of Cologne

  • Thomas Lorenz, Gerhard Kolland, Sandra Niesen, Oliver Breunig
    Theme: Heat capacity and capacitive dilatometry is used to explore thermal expansion and magnetostriction in complex transition metal oxides. This work is focused on spin state transitions of 3d6 ions Co3+ and Fe2+. Further collaborations concern thermal and electric conductivity down to low temperatures (0.3 K) and high magnetic fields.

    Markus Braden
    Theme: Elastic and inelastic neutron diffraction at reactors and spallation sources to determine magnetic order long range order and spin dynamics. The aim is to find materials that exhibit strong magnetoelastic couplings and multiferroidicity.

    Markus Grüninger, Reinhard Rückamp
    Theme: Spectroscopic investigations in reflection and transmission mode in the Raman-Infrared-Visible-UV (100-50000 cm-1) range on orbital and magnetic excitations. Information on optical band gaps and crystal field splitting of d-orbitals on transition metals are also of essence.

    Joachim Hemberger, Christoph Grams
    Theme: Dielectric spectroscopy in the very low energy (GHz-THz) range to identify domain wall motions in the vicinity of phase transitions. The investigated materials are related to spin ice pyrochlore Dy2Ti2O7.

    Mohsen Abd-Elmeguid
    Theme: Mössbauer spectroscopy of europium compounds to establish the oxidation state and the magnetic contribution of Eu in relatively simple solid state inorganic materials.

    Theoretical Physics Department, University of Cologne

  • Lars Fritz
    Theme: Comparing measured neutron scattering factors of geometrically frustrated systems (kagome lattices) with ground state predictions based on magnetic relative coupling constants in theoretical models. Spin-wave dispersions are also modelled and compared with inelastic neutron scattering data.

    Peter Grünberg Department, FZ Jülich

  • Raphael Hermann
    Theme: Fe Mössbauer spectroscopy of geometrically frustrated transition metal based oxides, to asses the local symmetry and oxidation state of Fe.

    Inorganic Chemistry, Ruhr University of Bochum

  • Guangmei Wang, Xinjiao Wang, Eike Torben Spielberg
    Theme: Investigations of magnetic liquids, i.e. ferrofluids, and hydrothermally synthesized new transition metal based compounds with complex anionic sublattices e.g. hydroxophosphates or fluorohydrates.

    Structural Chemistry, Ångström Laboratory, Uppsala University

  • Cesar-Pay Gomez
    Theme: Thermodynamic properties of quasi-crystal approximants. We want to understand the possible structural or magnetic transitions in the vicinity of a quasi periodic crystal lattice. At the moment, a Yb-Au-Sn system is in focus.

    Iowa State University, USA

  • Gerd Meyer, Eva Meyer, Simon Steinberg
    Theme: Magnetic properties of new rare-earth- (RE) and transition metal compounds. The new compounds either consist of metal-organic frameworks (MOFs) or defined metal clusters isolated by iodine or bromine matrices. Further, new ternary rare-earth metal compound with complex anionic lattices are examined e.g. RETeCl.

    Anja-Verena Mudring
    Theme: Investigations of new compounds from hydrothermal synthesis, including transition metal hydroxophosphates or fluorohydrates with novel metal lattices.

    Institut für Festkörper Forschung, IFW, Dresden

  • Vladislav Kataev
    Theme: Zero-field nuclear magnetic resonance (NMR) of complex metal oxides with strong magnetic frustration.

    Ulrich Rössler
    Theme: Density funcitonal theoretical calculations (LDA+U, GGA+U) on magnetic lattices with possible geometrical frustration.

    Department of Materials, ETH, Zürich

  • Mannfred Fiebig, Dennis Meier, Naomi Leo
    Theme: For ions with local non-centrosymmetry it is possible to use second harmonic generation (SHG) spectroscopy to investigate the polarity of an ion in its environment. Furthermore, materials with strong SHG can be used as frequency doubler in optical instruments. Multiferroic materials are of special interest here.