Research at Neutron Diffraction Group

Projects
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Frustrated Magnetism We are studying various frustrated magnets, including well-developed model systems such as the spin ices, as well as the first studies of new compounds using advanced microscopic probes such as neutron and x-ray scattering. We have three projects to investigate systems with different dimensionalities and geometries of the lattice and contrasting classical and quantum spins.

Details Neutron Diffraction Group , Neutron Spectroscopy Group
Christian Rüegg
christian.rueegg@psi.ch
Oksana Zaharko
oksana.zaharko@psi.ch
Tom Fennell
tom.fennell@psi.ch


Low Dimensional Magnetism 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.

Details Neutron Diffraction Group , Neutron Spectroscopy Group
Christian Rüegg
christian.rueegg@psi.ch

New Multiferroic Compounds for Spintronics derived from Delafossite Multiferroics are a small class of materials which exhibit both magnetic order and a spontaneous polarization. Ideally for possible applications, the magnetism can be controlled by an electric field and the polarization by a magnetic field. Delafossite (CuFeO2) and the isostructural CuCrO2 possess these sought after properties due to an unusual spin-charge coupling mechanism. The scope of this project is to investigate possibilities to influence this spin-charge coupling and search for further Delafossite-derived multiferroics.

Details Neutron Diffraction Group
Matthias Frontzek
matthias.frontzek@psi.ch

Superstructures in Iron Superconductors Neutron and synchrotron diffraction studies reveal the iron vacancy and spin order in alkali-earth iron selenide superconductors.


Details Neutron Diffraction Group
Vladimir Pomjakushin
vladimir.pomjakushin@psi.ch
Denis Cheptiakov
denis.cheptiakov@psi.ch


High Temperature Superconductors 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.


Details Neutron Diffraction Group , Neutron Spectroscopy Group , KuR Group
Christof Niedermayer
christof.niedermayer@psi.ch

Carbon-based Materials for Hydrogen Storage Synthesis and characterization of hydrogen absorption and desorption in the light metal intercalated fullerides MxC60 (M=Na, Li, Mg).

Details Neutron Diffraction Group
Denis Cheptiakov
denis.cheptiakov@psi.ch

Oxygen Diffusion and Structural Distortion in Brown-Millerites and Perovskites Solid state fuel cells (SOFC) will play key role in green technologies as they are efficiently producing electricity with low emissions. Our consortium investigates the complex structural behavior of La2CoO4+x, La2-xSrxCuO4+y and related materials as this materials show oxygen diffusion at moderate temperatures. We work in a consortium between PSI, Montpellier (France), Torino (Italy) and ILL (Grenoble).

Details Neutron Diffraction Group
Jürg Schefer
juerg.schefer@psi.ch
Lukas Keller
lukas.keller@psi.ch


Colossal Magnetoresistance Manganites and Cobaltites Crystal structure, orbital, charge and spin ordering, isotope effects and phase separation effects are studied in the mixed valence CMR manganites A1-xA’xMnO3 and cobaltites R1-yMyCo2O6-x by means of neutron and X-ray (synchrotron) diffraction and inelastic neutron scattering.

Details Neutron Diffraction Group
Vladimir Pomjakushin
vladimir.pomjakushin@psi.ch

Critical Phenomena in Ferroelectrics We are investigating the lattice dynamics close to Tc in both relaxor ferroelectrics like PbMg1/3Nb2/3O3 (PMN), PbMg1/3Ta2/3O3 (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.

Details Neutron Diffraction Group , Neutron Spectroscopy Group
Bertrand Roessli
bertrand.roessli@psi.ch

Magnetic Layered Systems Neutron scattering is used to investigate magnetic correlations and magnetic ordering phenomena in layered systems.

Details Neutron Diffraction Group , Neutron Spectroscopy Group
Oksana Zaharko
oksana.zaharko@psi.ch

Materials for Optical Applications and Nanocrystalline Materials 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.

Details Neutron Diffraction Group
Jürg Schefer
juerg.schefer@psi.ch