title: 13C NMR Spectroscopy of KxC60: Phase Separation, Molecular Dynamics, and Metallic Properties.
abstract: The results of (13)C nuclear magnetic resonance (NMR) measurements on alkali fullerides KxC(60) are reported. The NMR spectra demonstrate that material with 0 < x < 3 is in fact a two-phase system at equilibrium, with x = 0 and x = 3. NMR lineshapes indicate that C(3-)(60) ions rotate rapidly in the K(3)C(60) phase at 300 K, while C(6)-(60) ions in the insulating K(6)C(60) phase are static on the time scale of the lineshape measurement. The temperature dependence of the (13)C spin-lattice relaxation rate in the normal state of K(3)C(60) is found to be characteristic of a metal, indicating the important role of the C(3-)(60) ions in the conductivity. From the relaxation measurements, an estimate of the density of electronic states at the Fermi level is derived.
authors.forename: R
authors.initials: R
authors.lastname: Tycko
authors.forename: G
authors.initials: G
authors.lastname: Dabbagh
authors.forename: M J
authors.initials: MJ
authors.lastname: Rosseinsky
authors.forename: D W
authors.initials: DW
authors.lastname: Murphy
authors.forename: R M
authors.initials: RM
authors.lastname: Fleming
authors.forename: A P
authors.initials: AP
authors.lastname: Ramirez
authors.forename: J C
authors.initials: JC
authors.lastname: Tully