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(114) Production(s) de LE PARC R.
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Temperature scanning small angle x-ray scattering measurements of structural relaxation in type-III vitreous silica 
Auteur(s): Brüning Ralf, Levelut C., Le Parc R., Faivre A., Semple Lyne, Vallée Marc, Simon J., Hazemann Jean-Louis
(Article) Publié:
Journal Of Applied Physics, vol. 102 p.083535 (2007)
Ref HAL: hal-00186477_v1
DOI: 10.1063/1.2799940
WoS: 000250589300052
Exporter : BibTex | endNote
8 Citations
Résumé: The fictive temperature of vitreous silica containing approximately 900 wt ppm of hydroxyl groups was monitored with small angle x-ray scattering. The measurements were carried out during annealing and while scanning the temperature, with annealing temperatures ranging between 930 and 1330 K. Fitting the data to the Adam-Gibbs-Fulcher equation by using the Tool-Narayanaswamy method yields a particularly simple thermorheological behavior for type-III vitreous silica. Unlike the general case for glass kinetics, including vitreous silica with low hydroxyl content, the relaxation time constant is nearly decoupled from the fictive temperature. This high degree of decoupling of the state of the glass and the relaxation rate agrees with the results of viscosity measurements. By improving the data analysis procedure, we have significantly increased the precision of the results, and it was possible to resolve changes of the activation energy of the relaxation processes to within 0.5%. This has made sample aging effects that had previously been undetectable visible.
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X-Ray Diffraction Study of Presure-Induced Phase Transitions in GeTe-Sb 2 Te 3 (GST) System, a Material used as Phase Change optical Recording
Auteur(s): Levelut C., Le Parc R., Haines Julien, Krbal Milos, Kolobov Alex, Pradel Annie, Ribes Michel, Fons Paul, Tominaga J., Hanfland Michael
(Affiches/Poster)
Workshop on Advances in High Pressure Crystallography at large Scale Facilities (Wadham College , Oxford, GB), 2007-09-04 |
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High pressure study of amorphized and vitreous phase of mixed compound from the quartz family
Auteur(s): Le Parc R.
Conference: Joint 21 st AIRAPT and 45 th EHPRG International Conference on High Pressure Science and Technology to be held in Catania (Catania, Italy, FR, 2007-09-19)
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High pressure amorphisation in Al 1 - x Ga x PO 4
Auteur(s): Levelut C., Le Parc R., Haines Julien, Cambon Olivier, Pereira Altair
(Affiches/Poster)
Joint 21st AIRAPT and 45th EHPRG International Conference on High Pressure Science and Technology (Catania, Italy, FR), 2007-09-17 |
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Amorphisation sous pression de différents composés
Auteur(s): Levelut C., Le Parc R., Haines Julien, Cambon Olivier, Kolobov Alex, Pradel Annie, Agafonov V., Davydov V. a.
(Affiches/Poster)
5ieme forum de technologie des hautes pression (Monthieux, FR), 2006-11-06 |
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Dynamic sound attenuation at hypersonic frequencies in silica glass
Auteur(s): Levelut C., Le Parc R., Pelous Jacques
(Article) Publié:
Physical Review B, vol. 73 p.0652201 (2006)
Texte intégral en Openaccess : 
Ref HAL: hal-00016521_v1
Ref Arxiv: cond-mat/0601096
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
Résumé: In order to clarify the origin of the dominant processes responsible for the acoustic attenuation of phonons, which is a much debatted topic, we present Bril louin scattering experiments in various silica glasses of different OH impurities content. A large temperature range, from 5 to 1500 K is investigated, up to the glass transition temperature. Comparison of the hypersonic wave attenuation in various samples allows to identify two different processes. The first one induce s a low temperature peak related to relaxational processes; it is strongly sensitive to the extrinsic defects. The second, dominant in the hig h temperature range, is weakly dependent on the impurities and can be ascribed to anharmonic interactions.
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Influence of thermal history on the structure and properties of silicate glasses
Auteur(s): Levelut C., Le Parc R., Faivre A., Champagnon Bernard
(Article) Publié:
Journal Of Non-Crystalline Solids, vol. 352 p.4495 (2006)
Texte intégral en Openaccess :
Ref HAL: hal-00109830_v1
Ref Arxiv: cond-mat/0610698
DOI: 10.1016/j.jnoncrysol.2006.02.135
WoS: 000242821800020
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
32 Citations
Résumé: We studied a set of float glass samples prepared with different fictive temperature by previous annealing around the glass transition temperature. We compared the results to previous measurements on a series of amorphous silica samples, also prepared with different fictive temperature. We showed that the modifications on the structure at a local scale are very small, the changes of physical properties are moderate but the changes on density fluctuations at a nanometer scale are rather large: 12 and 20% in float glass and silica, for relative changes of fictive temperature equal to 13 and 25% respectively. Local order and mechanical properties of silica vary in the opposite way compared to float glass (anomalous behavior) but the density fluctuations in both glasses increase with temperature and fictive temperature.
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