59Co-NMR Knight Shift of Superconducting Three-Layer NaxCoO2.yH2O
arXiv:cond-mat/0507021 · doi:10.1143/JPSJ.74.2563
Abstract
The superconducting state of NaxCoO2.yH2O with three CoO2 layers in a unit cell has been studied by 59Co-NMR. The Knight shift measured for a peak of the NMR spectra corresponding to the external magnetic field H along one of the principal directions within the CoO2 plane, exhibits a rapid decrease with decreasing temperature T below the superconducting transition temperature Tc, indicating that the spin susceptibility is suppressed in the superconducting phase, at least, for this field direction. Because differences of the superconducting properties are rather small between this three-layer NaxCoO2.yH2O and previously reported NaxCoO2.yH2O with two CoO2 layers within a unit cell, the present result of the Knight shift studies indicates that the Cooper pairs of the former system are in the singlet state as in the latter, for which the spin susceptibility is suppressed for both directions of H parallel and perpendicular to the CoO2 plane.
arXiv comment5 pages
References in corpus (16)
- Unconventional Superconductivity and Electron Correlations in Cobalt Oxyhydrate NaCoOHO
- Thermodynamic and Transport Measurements on Superconducting Na_xCoO_2 + yH_2O Single Crystals Prepared by Electrochemical De-intercalation
- Unconventional Superconductivity and Nearly Ferromagnetic Spin Fluctuations in NaCoOHO
- Transport and Magnetic Studies on the Spin State Transition of Pr1-xCaxCoO3 up to High Pressure
- Magnetic Structures of High Temperature Phases of TbBaCo2O5.5
- 59Co-NMR Knight Shift of the Superconducting NaxCoO2.yH2O
- Multi-orbital analysis on the Superconductivity in Na_{x}CoO_{2} \cdot y H_{2}O
- Possibility of f-wave spin-triplet superconductivity in the CoO superconductor: a case study on a 2D triangular lattice in the repulsive Hubbard model
- 59Co-NMR Knight Shift of Aligned Crystals and Polycrystalline Samples of Superconducting Na0.3CoO2.1.3H2O
- Competition between singlet and triplet pairings in Na_xCoO_2 yH_2O
- Magnetic Structures and Spin States of NdBaCo2O5
- Impurity Effects on the Superconducting Transition Temperature of NazCoO2.yH2O
- Ferromagnetic and triplet-pairing instabilities controlled by the trigonal distortion of the CoO_6 octahedra in Na_xCoO_2*yH_2O
- Superconducting Properties under Magnetic Field in NaCoOHO Single Crystal
- Superconductivity in three-layer Na0.3CoO2*1.3H2O
- Correlation between Tc and Lattice Parameters of Novel Superconducting NaxCoO2 yH2O