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Title: High-resolution neutron diffraction study of possible charge ordering in Na{sub 0.5}CoO{sub 2}

Abstract

The structure of Na{sub 0.5}CoO{sub 2}, the low-temperature insulator that separates the antiferromagnetic and normal metals in the Na{sub x}CoO{sub 2} phase diagram, is studied by high-resolution powder neutron diffraction at temperatures between 10 and 300 K. Profile analysis confirms that it has an orthorhombic symmetry structure, space group Pnmm, consisting of layers of edge-sharing CoO{sub 6} octahedra in a triangular lattice, with Na ions occupying ordered positions in the interleaving planes. The oxygen content is found to be stoichiometric within 1%, indicating that the Na concentration accurately determines the electronic doping. The Na ordering creates two distinct Co sites, in parallel chains running along one crystallographic direction. The differences in their Co-O bond distances and the derived bond valence sums, reflections of the degree of charge ordering in this phase, are very small.

Authors:
;  [1]; ; ;  [2]
  1. Centre for Science at Extreme Conditions and School of Chemistry, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JZ (United Kingdom)
  2. Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)
Publication Date:
OSTI Identifier:
20788043
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 73; Journal Issue: 13; Other Information: DOI: 10.1103/PhysRevB.73.134401; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANTIFERROMAGNETISM; BOND LENGTHS; COBALT OXIDES; LAYERS; NEUTRON DIFFRACTION; ORTHORHOMBIC LATTICES; OXYGEN; PHASE DIAGRAMS; REFLECTION; RESOLUTION; SODIUM COMPOUNDS; SODIUM IONS; SPACE GROUPS; STOICHIOMETRY; SYMMETRY; TEMPERATURE DEPENDENCE; VALENCE

Citation Formats

Williams, A. J., Attfield, J. P., Foo, M. L., Viciu, L., and Cava, R. J.. High-resolution neutron diffraction study of possible charge ordering in Na{sub 0.5}CoO{sub 2}. United States: N. p., 2006. Web. doi:10.1103/PHYSREVB.73.1.
Williams, A. J., Attfield, J. P., Foo, M. L., Viciu, L., & Cava, R. J.. High-resolution neutron diffraction study of possible charge ordering in Na{sub 0.5}CoO{sub 2}. United States. doi:10.1103/PHYSREVB.73.1.
Williams, A. J., Attfield, J. P., Foo, M. L., Viciu, L., and Cava, R. J.. Sat . "High-resolution neutron diffraction study of possible charge ordering in Na{sub 0.5}CoO{sub 2}". United States. doi:10.1103/PHYSREVB.73.1.
@article{osti_20788043,
title = {High-resolution neutron diffraction study of possible charge ordering in Na{sub 0.5}CoO{sub 2}},
author = {Williams, A. J. and Attfield, J. P. and Foo, M. L. and Viciu, L. and Cava, R. J.},
abstractNote = {The structure of Na{sub 0.5}CoO{sub 2}, the low-temperature insulator that separates the antiferromagnetic and normal metals in the Na{sub x}CoO{sub 2} phase diagram, is studied by high-resolution powder neutron diffraction at temperatures between 10 and 300 K. Profile analysis confirms that it has an orthorhombic symmetry structure, space group Pnmm, consisting of layers of edge-sharing CoO{sub 6} octahedra in a triangular lattice, with Na ions occupying ordered positions in the interleaving planes. The oxygen content is found to be stoichiometric within 1%, indicating that the Na concentration accurately determines the electronic doping. The Na ordering creates two distinct Co sites, in parallel chains running along one crystallographic direction. The differences in their Co-O bond distances and the derived bond valence sums, reflections of the degree of charge ordering in this phase, are very small.},
doi = {10.1103/PHYSREVB.73.1},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 13,
volume = 73,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 2006},
month = {Sat Apr 01 00:00:00 EST 2006}
}