Structure and physical properties of NaxCoO2.yH2O superconducting system

Y. G. Shi; J. Q. Li; H. C. Yu; Y. Q. Zhou; H. R. Zhang; C. Dong

doi:10.1088/0953-2048/17/1/007

Structure and physical properties of NaxCoO2.yH2O superconducting system

Superconductivity 2009-11-10 v2 Strongly Correlated Electrons

Authors: Y. G. Shi , J. Q. Li , H. C. Yu , Y. Q. Zhou , H. R. Zhang , C. Dong

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Abstract

The structural properties of NaxCoO2 and NaxCoO2yH2O have been investigated. The NaxCoO2yH2O samples in general show up the superconducting transitions at around 3.5K. EDAX analyses suggest our samples have the average composition of Na0.65CoO2 for the parent compound and Na0.26CoO2yH2O for the superconducting crystals. TEM observation reveals a superstructure with wave vector q=<1/2,0, 0> in the parent Na0.65CoO2 materials. This superstructure becomes very weak in the superconducting oxyhydrates. EELS analyses show that the Co ions have the valence state of around +3.3 in the Na0.65CoO2 materials and around +3.7 in the superconducting materials.

Keywords

NaxCoO2 superconductivity structural properties TEM analysis EELS

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@article{arxiv.cond-mat/0306070,
  title  = {Structure and physical properties of NaxCoO2.yH2O superconducting system},
  author = {Y. G. Shi and J. Q. Li and H. C. Yu and Y. Q. Zhou and H. R. Zhang and C. Dong},
  journal= {arXiv preprint arXiv:cond-mat/0306070},
  year   = {2009}
}

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13pages, 5figures

Structure and physical properties of NaxCoO2.yH2O superconducting system

Abstract

Keywords

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