Superconducting properties under magnetic field in Na 0.35CoO2·1.3H2O single crystal

Takahiko Sasaki, Petre Badica, Naoki Yoneyama, Kazuyoshi Yamada, Kazumasa Togano, Norio Kobayashi

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


We report the in-plane resistivity and magnetic susceptibility of the layered cobalt oxide Na0.35CoO2·1.3H2O single crystal. The temperature dependence of the resistivity shows metallic behavior from room temperature to the superconducting transition temperature Tc of 4.5 K. A sharp resistive transition, zero resistivity and almost perfect superconducting volume fraction below Tc indicate the good quality and bulk superconductivity of the single crystal. The upper critical field Hc2 and coherence length ξ are obtained from the resistive transitions in the magnetic fields parallel to the c-axis and ab-plane. The anisotropy of ξ, ξabc = 12 nm/1.3 nm ≃ 9.2, suggests that this material is an anisotropic three-dimensional superconductor. In the field parallel to the ab-plane, Hc2 seems to be suppressed to the Pauli paramagnetic limit. This suggests spin singlet superconductivity in the cobalt oxide.

Original languageEnglish
Pages (from-to)1131-1134
Number of pages4
Journaljournal of the physical society of japan
Issue number5
Publication statusPublished - 2004 May


  • Anisotropy
  • NaCoO·1.3HO
  • Superconductivity
  • Upper critical field

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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