Three-dimensional spin fluctuations in Na0.75CoO2

We report polarized- and unpolarized-neutron scattering measurements of magnetic excitations in single-crystal Na0.75CoO2. The data confirm ferromagnetic correlations within the cobalt layers and reveal antiferromagnetic correlations perpendicular to the layers, consistent with an A-type antiferroma...

Full description

Saved in:
Bibliographic Details
Published inPhysical review letters Vol. 94; no. 15; p. 157206
Main Authors Helme, L M, Boothroyd, A T, Coldea, R, Prabhakaran, D, Tennant, D A, Hiess, A, Kulda, J
Format Journal Article
LanguageEnglish
Published United States 22.04.2005
Online AccessGet more information

Cover

More Information
Summary:We report polarized- and unpolarized-neutron scattering measurements of magnetic excitations in single-crystal Na0.75CoO2. The data confirm ferromagnetic correlations within the cobalt layers and reveal antiferromagnetic correlations perpendicular to the layers, consistent with an A-type antiferromagnetic ordering. The magnetic modes propagating perpendicular to the layers are sharp, and reach a maximum energy of approximately 12 meV. From a minimal spin-wave model, containing only nearest-neighbor Heisenberg exchange interactions, we estimate the interlayer and intralayer exchange constants to be 12.2+/-0.5 meV and -6+/-2 meV, respectively. We conclude that the magnetic fluctuations in Na0.75CoO2 are highly three dimensional.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.94.157206