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(165) Production(s) de RUFFLE B.
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Brillouin scattering study of hypersonic attenuation in GeO-2
Auteur(s): Guimbretiere Guillaume, Ruffle B., Vacher R.
(Affiches/Poster)
International Workshop on Dynamics in Viscous Liquids (Munich, Germany, FR), 2004-03-14 |
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Observation of the onset of strong scattering on high frequency acoustic phonons in densified silica glass 
Auteur(s): Ruffle B., Foret M., Courtens E., Vacher R., Monaco G.
(Article) Publié:
Physical Review Letters, vol. 90 p.095502 (2003)
Texte intégral en Openaccess : 
Ref HAL: hal-00117305_v1
Ref Arxiv: cond-mat/0301490
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: The linewidth of longitudinal acoustic waves in densified silica glass is obtained by inelastic x-ray scattering. It increases with a high power alpha of the frequency up to a crossover where the waves experience strong scattering. We find that \alpha is at least 4, and probably larger. Resonance and hybridization of acoustic waves with the boson-peak modes seems to be a more likely explanation for these findings than Rayleigh scattering from disorder.
Commentaires: 4 pages, 4 figures
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Central peak near the incommensurate displacive phase transition of BCPS
Auteur(s): Ollivier J., Ruffle B., Longeville S., Bourges P., Lechner R. E., Toudic B.
(Article) Publié:
The Journal Of Chemical Physics, vol. 292 p.171-183 (2003)
Résumé: We report on a high resolution neutron study of the dynamical response of bis (4-chlorophenyl) sulfon near its displacive structural phase transition. On the basis of previous estimations of the soft mode characteristics [1], we show that for this molecular compound the narrow central peak arising at the transition can be partially energy resolved. The central line can be described as composed of, at least, two contributions with different energy scales: a weak relaxation in the 10 GHz frequency range and a main component, elastic within the neutron energy window. These results are analyzed in the light of existing microscopic models. (C) 2003 Elsevier Science B.V. All rights reserved.
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The crossover from propagating to strongly scattered acoustic modes of glasses observed in densified silica
Auteur(s): Courtens E., Foret M., Hehlen B., Ruffle B., Vacher R.
(Article) Publié:
Journal Of Physics: Condensed Matter, vol. 15 p.S1279-S1290 (2003)
Résumé: Spectroscopic results on low-frequency excitations of densified silica are presented and related to characteristic thermal properties of glasses. The end of the longitudinal acoustic branch is marked by a rapid increase of the Brillouin linewidth with the scattering vector. This rapid growth saturates at a crossover frequency Omega(co) which nearly coincides with the centre of the boson peak. The latter is clearly due to additional optic-like excitations related to nearly rigid SiO4 librations as indicated by hyper-Raman scattering. Whether the onset of strong scattering is best described as resulting from hybridization of acoustic modes with these librations, from their elastic scattering (Rayleigh scattering) on the local excitations, or from, soft potentials remains to be established.
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What can we learn the long-range structure of glasses from relaxations and vibrations ?
Auteur(s): Vacher R., Courtens E., Foret M., Hehlen B., Ruffle B.
Conference: 2 nd International Symposium on Non-Crystalline Solids (Campos do Jordao, Brazil, FR, 2003-09-21)
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The boson peak of oxide glasses and its relation with the end of acoustic branches
Auteur(s): Hehlen B., Ruffle B., Foret M., Vacher R., Courtens E.
Conference: 4th Congres de la Societe Venezuelienne de Physique (Ile Margarita, Venezuela, FR, 2003-09-24)
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High frequency sound in glasses
Auteur(s): Courtens E., Foret M., Hehlen B., Ruffle B., Vacher R.
Conference: 2nd International Conference on Materials for Advanced Technologies, Symposium J on Synchrotron Radiation for Advanced Materials Analysis and Processing (Singapore, FR, 2003-12-07)
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