Hydration-induced anisotropic spin fluctuations in NaxCoO 2 1.3H2O superconductor

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Abstract

We report 59Co NMR studies in single crystals of the cobalt oxide superconductor Na0.42CoO21.3H2O (T c=4.25 K) and its parent compound Na0.42CoO2. We find that both the magnitude and the temperature (T) dependence of the Knight shifts are identical in the two compounds above Tc. The spin-lattice relaxation rate (1/T1) is also identical above T0∼60 K for both compounds. Below T0, the unhydrated sample is found to be a non-correlated metal that well conforms to the Fermi liquid theory, while spin fluctuations develop in the superconductor. These results indicate that water intercalation does not change the density of states at the Fermi level or the carrier density but its primary role is to bring about spin fluctuations. Our result shows that, in the hydrated superconducting compound, the electron correlation is anisotropic. Namely, the spin fluctuation around the finite wave vector is much stronger along the a-axis direction than that along the c-axis direction.

Original languageEnglish
Article number57010
JournalEPL
Volume84
Issue number5
DOIs
Publication statusPublished - 2008

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hydration
nuclear magnetic resonance
cobalt oxides
Fermi liquids
intercalation
spin-lattice relaxation
single crystals
metals
water
electrons
temperature

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Hydration-induced anisotropic spin fluctuations in NaxCoO 2 1.3H2O superconductor. / Matano, Kazuaki; Lin, C. T.; Zheng, Guo-Qing.

In: EPL, Vol. 84, No. 5, 57010, 2008.

Research output: Contribution to journalArticle

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