We have measured the low-energy inelastic neutron scattering spectra of superconducting Na2CsC60 in the temperature range 100-350 K. Well-defined librational peaks are observed at 2.7(1) meV; their position and width are temperature independent. They survive well above the order-disorder transition at 299 K. A quasielastic feature with a width 1.03(6) meV at an average scattering vector of 1.09 Å-1 is observed at 350 K, arising from diffusive motion of the C3-60 ions. Evidence is found for influence of the Na+ ions on the rotational motion of the C3-60 ions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering