Sodium Ion Ordering in NaxCoO2

H. W. Zandbergen; M. L. Foo; Q. Xu; V. Kumar; R. J. Cava

Sodium Ion Ordering in NaxCoO2

Superconductivity 2007-05-23 v1

Authors: H. W. Zandbergen , M. L. Foo , Q. Xu , V. Kumar , R. J. Cava

Abstract

The layered sodium cobalt oxide NaxCoO2 is studied by electron diffraction for a wide range of sodium contents, 0.15<x<0.75. An extensive series of ordered Na ion-Na vacancy superlattices is found beyond the simple hexagonal average structure. The most strongly developed superlattice is found for the composition Na0.5CoO2, which displays Co3+/Co4+ charge ordering at low temperatures. The structural principle for some of the observed ordering schemes, particularly near x=0.5, is, surprisingly, the presence of lines of Na ions and vacancies rather than simply maximized Na-Na separations.

Keywords

phase transitions charge ordering

Cite

@article{arxiv.cond-mat/0403206,
  title  = {Sodium Ion Ordering in NaxCoO2},
  author = {H. W. Zandbergen and M. L. Foo and Q. Xu and V. Kumar and R. J. Cava},
  journal= {arXiv preprint arXiv:cond-mat/0403206},
  year   = {2007}
}

Comments

16 pages,13 figures

Related papers

View all related →