 |
 |
|
Stewart, J. R., Ehlers, G., Mutka, H., Fouquet, P., Payen, C. & Lortz, R. (2011) Spin dynamics, short-range order, and spin freezing in Y0.5Ca0.5BaCo4O7. Phys. Rev. B, 83 024405.
Added by: Laurent Cournède (2016-03-10 21:32:21) |
| Type de référence: Article DOI: 10.1103/PhysRevB.83.024405 Numéro d'identification (ISBN etc.): 1098-0121 Clé BibTeX: Stewart2011 Voir tous les détails bibliographiques  |
Catégories: MIOPS Mots-clés: glass, kagome antiferromagnet, lattice, magnetic frustration, neutron polarization analysis, scattering, spectroscopy, srcr8ga4o19, temperature, ybaco4o7+delta Créateurs: Ehlers, Fouquet, Lortz, Mutka, Payen, Stewart Collection: Phys. Rev. B |
Consultations : 1/588
Indice de consultation : 4% Indice de popularité : 1% |
| Résumé |
|
Y0.5Ca0.5BaCo4O7 was recently introduced as a possible candidate for capturing some of the predicted classical spin kagome ground-state features. Stimulated by this conjecture, we have taken up a more complete study of the spin correlations in this compound with neutron scattering methods on a powder sample characterized with high-resolution neutron diffraction and the temperature dependence of magnetic susceptibility and specific heat. We have found that the frustrated near-neighbor magnetic correlations involve not only the kagome planes but concern the full Co sublattice, as evidenced by the analysis of the wave-vector dependence of the short-range order. We conclude from our results that themagnetic moments are located on the Co sublattice as a whole and that correlations extend beyond the two-dimensional kagome planes. We identify intriguing dynamical properties, observing high-frequency fluctuations with a Lorentzian linewidth Gamma {<}= 20 meV at ambient temperature. On cooling a low-frequency (similar to 1 meV) dynamical component develops alongside the high-frequency fluctuations, which eventually becomes static at temperatures below T approximate to 50 K. The high-frequency response with an overall linewidth of similar to 10 meV prevails at T {<}= 2 K, coincident with a fully elastic short-range-ordered contribution.
Added by: Laurent Cournède |