Preparation and transport properties of non-hydrated NaCoO single crystals
XZ Chen, ZA Xu, GH Cao, JQ Shen, LM Qiu… - arXiv preprint cond-mat …, 2004 - arxiv.org
XZ Chen, ZA Xu, GH Cao, JQ Shen, LM Qiu, ZH Gan
arXiv preprint cond-mat/0412299, 2004•arxiv.orgSingle crystals of Na $ _ {0.5} $ CoO $ _2 $ were obtained through a flux method followed
by de-intercalation of sodium. The Na $ _ {0.5} $ CoO $ _2 $ samples were found to be
vulnerable to water in the air and a hydration process in which H $ _2 $ O molecules fill
oxygen vacancies in CoO $ _2 $ layers is suggested to be responsible for the unusual
vulnerability to water. The transport properties, including resistivity (\emph {$\rho $}),
thermopower (\emph {S}) and Hall coefficient (\emph {R $ _H $}), were studied in a …
by de-intercalation of sodium. The Na $ _ {0.5} $ CoO $ _2 $ samples were found to be
vulnerable to water in the air and a hydration process in which H $ _2 $ O molecules fill
oxygen vacancies in CoO $ _2 $ layers is suggested to be responsible for the unusual
vulnerability to water. The transport properties, including resistivity (\emph {$\rho $}),
thermopower (\emph {S}) and Hall coefficient (\emph {R $ _H $}), were studied in a …
Single crystals of NaCoO were obtained through a flux method followed by de-intercalation of sodium. The NaCoO samples were found to be vulnerable to water in the air and a hydration process in which HO molecules fill oxygen vacancies in CoO layers is suggested to be responsible for the unusual vulnerability to water. The transport properties, including resistivity (\emph{}), thermopower (\emph{S}) and Hall coefficient (\emph{R}), were studied in a temperature range of 5-300 K. The compound shows a weak localization of carriers just below 200 K and Co-Co charge ordering at about 30 K, a relatively lower temperature than previously reported. The results seem to be quite different from those previously reported for this system [Foo et al, Phys. Rev. Lett. 92 (2004) 247001]. Possible mechanism underlying this kind of inconsistency is discussed.
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