Details

Autor(en) / Beteiligte

• HELME, L. M
• BOOTHROYD, A. T
• COLDEA, R
• PRABHAKARAN, D
• TENNANT, D. A
• HIESS, A
• KULDA, J

Titel

Three-dimensional spin fluctuations in Na0.75CoO2

Ist Teil von

• Physical review letters, 2005-04, Vol.94 (15), p.157206.1-157206.4

Ort / Verlag

Ridge, NY: American Physical Society

Erscheinungsjahr

2005

Quelle

American Physical Society

Beschreibungen/Notizen

• 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.