Non-classical phenomena in Quantum Spin Systems, including their ground states and dynamics are in focus of our research using neutronscattering techniques. Recent results have been obtained on dimer compounds, coupled spin tetrahedral systems and spin-bath concepts of quantum phase transitions.

Crystal structure, orbital, charge and spin ordering, isotope effects and phase separation effects are studied in the mixed valence CMR manganites A_1-xA'_xMnO₃ and cobaltites R_1-yM_yCo₂O_6-x by means of neutron and X-ray (synchrotron) diffraction and inelastic neutron scattering.

We are investigating the lattice dynamics close to Tc in both relaxor ferroelectrics like PbMg_1/3Nb_2/3O₃ (PMN), PbMg_1/3Ta_2/3O₃ (PMT) and classical ferroelectrics (KNbO₃, KTaO₃). We found that for both class of compounds quasi-elastic (QE) scattering coexists with a central peak in the viciniy of the phase transition. The origin of this QE scattering intensity is not understood at moment. We found first that its susceptibility correlates well with the temperature dependence of the dielectric susceptibility (and hence plays a role in the phase transition) and second is related to short-range atomic disorder in the crystals that appears in the form of diffuse scattering in the neutron spectra.

Neutron scattering is used to investigated strong correlations in inter-metallic systems. Topics such as coexistence of superconductivity and magnetism, quantum critical points, pressure-induced valence and phase transitions, as well as orbital ordering phenomena are the focus of this project.

Polarised neutron reflectometry is able to probe the structural and magnetic properties of layered systems on a nanometer scale. We employ this technique to understand the fundamental interactions and related quantum-phenomena that emerge when two materials are brought in contact with each other.

Neutron scattering is employed to investigate both the magnetic excitations and the Abrikosov phase diagram of high-temperature supercondcutors. The results are then confronted to both theroetical and experimental results obtained form other probe like, for example, ARPES, tunneling or transport.

Optical active materials where the absorption or refraction index can be influenced with light will be important in technical applications such as data storage (holography) and laser materials (non-linear optical materials for frequency doubling), but also in medical applications by releasing NO-radicals with illumination of light.

The interaction of biomolecules as phospholipids and proteins with surfaces is investigated towards solid-liquid interfaces with and without specific or functional coatings using neutron reflectometry. The aim is to understand the physics behind this processes for the development of biocompatible surfaces and biosensing systems.

Surface relief submicro dot gratings (SMDG) are of considerable interest for opto-electronic applications as well as substrate materials for the covering with monodisperse colloidal spheres to implement order in colloid multilayers which can act as photonic crystals.