| Numéro |
J. Phys. Colloques
Volume 42, Numéro C6, Décembre 1981
International Conference on Phonon Physics
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|---|---|---|
| Page(s) | C6-782 - C6-784 | |
| DOI | https://doi.org/10.1051/jphyscol:19816231 | |
International Conference on Phonon Physics
J. Phys. Colloques 42 (1981) C6-782-C6-784
DOI: 10.1051/jphyscol:19816231
1 Laboratoire Léon Brillouin, CEN-Saclay, 91191 Gif-sur-Yvette, France
2 Institut Laue-Langevin, 156X, Centre de Tri, 38042 Grenoble Cedex, France
3 DPhG/PSRM, CEN-Saclay, 91191 Gif-sur-Yvette, France
J. Phys. Colloques 42 (1981) C6-782-C6-784
DOI: 10.1051/jphyscol:19816231
PHONON DISPERSION AND TRANSVERSE MODE SOFTENING IN RbFeCl3
D. Petitgrand1, B. Hennion1, C. Escribe-Filippini2 et S. Legrand31 Laboratoire Léon Brillouin, CEN-Saclay, 91191 Gif-sur-Yvette, France
2 Institut Laue-Langevin, 156X, Centre de Tri, 38042 Grenoble Cedex, France
3 DPhG/PSRM, CEN-Saclay, 91191 Gif-sur-Yvette, France
Abstract
Phonon dispersion curves of RbFeCl3 have been measured by neutron scattering. For wave vectors in the hexagonal plane the transverse phonons polarized along Z are found to have very low energies. Furthermore the shape of this branch changes drastically as the temperature is lowered from room temperature to 20K, the zone boundary energy at the K point being decreased by a factor of two. However no Bragg reflection indicative of a phase transition has been detected at this point. These features are interpreted as showing evidence that RbFeCl3 is at the border of a phase transition for which a microscopic mechanism will be discussed.