Valence and Na content dependences of superconductivity in NaxCoO2.yH2O

Abstract

Various samples of sodium cobalt oxyhydrate with relatively large amounts of Na${}^{+}$ ions were synthesized by a modified soft-chemical process in which a NaOH aqueous solution was added in the final step of the procedure. From these samples, a superconducting phase diagram was determined for a section of a cobalt valence of $\sim$+3.48, which was compared with a previously obtained one of $\sim$+3.40. The superconductivity was significantly affected by the isovalent exchanger of Na${}^{+}$ and H${}_3$O${}^{+}$, rather than by variation of Co valence, suggesting the presence of multiple kinds of Fermi surface. Furthermore, the high-field magnetic susceptibility measurements for one sample up to 30 T indicated an upper critical field much higher than the Pauli limit supporting the validity of the spin-triplet pairing mechanism.

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References in corpus (18)

• Superconductivity Phase Diagram of Na(x)CoO(2).1.3H(2)O
• Unconventional Superconductivity and Electron Correlations in Cobalt Oxyhydrate Na${}_{0.35}$CoO${}_2$$\cdot y$H${}_2$O
• Thermodynamic and Transport Measurements on Superconducting Na_xCoO_2 + yH_2O Single Crystals Prepared by Electrochemical De-intercalation
• Unconventional Superconductivity and Nearly Ferromagnetic Spin Fluctuations in Na${}_x$CoO${}_2$$\cdot y$H${}_2$O
• Origin of the Weak Pseudo-gap Behaviors in Na_{0.35}CoO_2: Absence of Small Hole Pockets
• The crystal growth and characterization of NaxCoO2 and NaxCoO2yH2O
• Unconventional Upper- and Lower-Critical Fields and Normal-State Magnetic Susceptibility of the Novel Superconducting Compound $N{a}_{0.35}Co{O}_2\cdot 1.3H_{2}O$
• Revised superconducting phase diagram of hole doped Na${}_x$(H${}_3$O)${}_z$CoO${}_2\cdot y$H${}_2$O
• Weak Magnetic Order in the Bilayered-hydrate Na${}_x$CoO${}_2\cdot y$H${}_2$O Structure Probed by Co Nuclear Quadrupole Resonance - Proposed Phase Diagram in Superconducting Na${}_x$CoO${}_2\cdot$ $y$H${}_2$O
• Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O
• Superconductivity and Cobalt Oxidation State in Metastable Na(x)CoO(2-delta)*yH2O (x ~ 1/3; y ~ 4x)
• Possible singlet to triplet pairing transition in NaxCoO2 H2O
• 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 Na${}_{0.35}$CoO${}_2\cdot 1.3$H${}_2$O Single Crystal
• Evidence of large anisotropy in the magnetization of Na0.35CoO2.1.3H2O quasi-single-crystal superconductors
• Role of spin-orbit coupling on the spin triplet pairing in Na_{x}CoO_{2}yH_{2}O II: Multiple phase diagram under the magnetic field
• Superconducting phase diagram of NaxCoO2.yH2O
• Thermal Expansion and Compressibility in Superconducting NaxCoO2o4xD2O (x?1/3): Evidence for Pressure-Induced Charge Redistribution

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