Superconductivity, charge ordering, and structural properties of α - and β−NaxCoO2∙y(H2O,D2O)
Year: 2006
Type: article
Abstract: Two series of $\ensuremath{\alpha}$- and $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$ materials have been prepared by means of Na deintercalation from the $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Na}\mathrm{Co}{\mathrm{O}}_{2}$ and $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Na}}_{0.6}\mathrm{Co}{\mathrm{O}}_{2}$ parent phases, respectively. The $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$ materials undergo a clear phase transition from the hexagonal to the $\ensuremath{\beta}$-phase-like monoclinic structure along with the Na deintercalation. Measurements of resistivity and magnetization demonstrated the presence of notable charge ordering transitions in both $\ensuremath{\alpha}$- and $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}$ with $0.4<x<0.5$ below $100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Bulk superconductivity has been observed in the hydrated $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}∙1.3{\mathrm{H}}_{2}\mathrm{O}$ at $\ensuremath{\sim}4.2\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ and in $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Na}}_{x}\mathrm{Co}{\mathrm{O}}_{2}∙1.3{\mathrm{H}}_{2}\mathrm{O}$ at $\ensuremath{\sim}4.3\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Intercalation of ${\mathrm{D}}_{2}\mathrm{O}$ in either $\ensuremath{\alpha}$- or $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Na}}_{0.33}\mathrm{Co}{\mathrm{O}}_{2}$ also yields superconductivity at slightly lower temperatures.
Source: Physical Review B
Authors: Y. G. Shi, H. X. Yang, H. Huang, X. Liu, J. Q. Li
Institutions: Chinese Academy of Sciences, Institute of Physics
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1658555192