title: 17O NMR studies of a triangular-lattice superconductor NaxCoO2 x yH(2)O.
abstract: We report the first 17O NMR studies of a triangular-lattice superconductor Na(1/3)CoO2 x 4/3H(2)O and the host material Na(x)CoO2 (x=0.35 and 0.72). Knight shift measurements reveal that p-d hybridization induces sizable spin polarization in the O triangular-lattice layers. Water intercalation makes CoO2 planes homogeneous and enhances low frequency spin fluctuations near T(c)=4.5 K at some finite wave vectors different from both the ferromagnetic and "120 degree" modes.
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