title: Spin dynamics in the carrier-doped S=1/2 triangular lattice of NaxCoO2.yH2O.
abstract: We probed the local electronic properties of the mixed-valent Co+4-x triangular lattice in NaxCoO2.yH(2)O by 59Co NMR. We observed two distinct types of Co sites for x > or =1/2, but the valence seems averaged out for x approximately 1/3. Local spin fluctuations exhibit qualitatively the same trend down to approximately 100 K regardless of the carrier concentration x, and hence the nature of the electronic ground state. A canonical Fermi-liquid behavior emerges below approximately 100 K only for x approximately 1/3.
authors.affiliation: Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada.
authors.forename: F L
authors.initials: FL
authors.lastname: Ning
authors.forename: T
authors.initials: T
authors.lastname: Imai
authors.forename: B W
authors.initials: BW
authors.lastname: Statt
authors.forename: F C
authors.initials: FC
authors.lastname: Chou