Magnetic ordering and spin waves in Na0.82CoO2

Authors

S P. Bayrakci, Max Planck Institute
I Mirebeau, Laboratoire Leon Brillouin, France
P Bourges, Laboratoire Leon Brillouin, France
Y Sidis, Laboratoire Leon Brillouin, France
M Enderle, Institut Laue Langevin
J Mesot, Paul Scherrer Institute
Dapeng Chen, Max-Planck-Institute For Solid State ResearchFollow
C T Lin, Max-Planck-Institute For Solid State Research
B Keimer, Max Planck Institute

RIS ID

41241

Publication Details

Bayrakci, S. P., Mirebeau, I., Bourges, P., Sidis, Y., Enderle, M., Mesot, J., Chen, D. P., Lin, C. & Keimer, B. (2005). Magnetic ordering and spin waves in Na0.82CoO2. Physical Review Letters, 94 (15), 157205-1-157205-4.

Abstract

NaxCoO2, the parent compound of the recently synthesized superconductor NaxCoO2∶yH2O, exhibits bulk antiferromagnetic order below ∼20   K for 0.75≤x≤0.9. We have performed neutron scattering experiments in which we observed Bragg reflections corresponding to A-type antiferromagnetic order in a Na0.82CoO2 single crystal and characterized the corresponding spin-wave dispersions. The spin waves exhibit a strongly energy-dependent linewidth. The in-plane and out-of-plane exchange constants resulting from a fit to a nearest-neighbor Heisenberg model are similar in magnitude, which is unexpected in view of the layered crystal structure of NaxCoO2. Possible implications of these observations are discussed.