Neutron Scattering for Materials Science

The work proposed involves the use of inelastic neutron scattering to explore the dynamics of materials in which different degrees of freedom (charge, spin and orbital magnetic moments, phonons) interact to produce superconductivity, thermoelectric effects, orbital ordering, and geometric frustration. These studies will involve collaboration between staff in the Neutron Sciences Directorate (Neutron Scattering Science Division) and the Physical Sciences Directorate (Correlated Electron Materials Group, Materials Science and Technology Division) at Oak Ridge National Laboratory. The inelastic neutron scattering studies will be predominantly undertaken using the wide Angular-Range Chopper Spectrometer (ARCS) and the Cold Neutron Chopper Spectrometer (CNCS) at the SNS. The ARCS spectrometer will be used to study the high energy dynamical processes in the 50-1000 meV range. Most relevant in this context are the vibrational modes related to the stability and phase transitions and the coupling of lattice and electronic degrees of freedom. At the CNCS spectrometer, dynamical processes will be studied at lower energies, below 50 meV. Specific materials that are included in this work are (i) new exotic magnetic and superconducting materials which can be found in families of ternary rare earth oxides with the pyrochlore or spinel structures, (ii) new arsenic-based superconductors and (iii) layered thermoelectric colbaltates. The Correlated Electron Materials Group at ORNL has been particularly successful in producing and studying these materials.