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High Pressure behaviour of v-SiO2 : Brillouin and polarized Raman study
Coralie Weigel  1@  , Marie Foret  1  , Benoit Rufflé  1  , Bernard Hehlen  1  , Alain Polian  2  
1 : Laboratoire Charles Coulomb  (L2C)  -  Website
Université Montpellier II - Sciences et techniques, CNRS : UMR5221
1 place Eugène Bataillon Université Montpellier II 34095 Montpellier Cedex 5 -  France
2 : Institut de minéralogie, de physique des matériaux et de cosmochimie  (IMPMC)  -  Website
Museum National d'Histoire Naturelle, Université Pierre et Marie Curie - Paris 6 : UM120, Institut de recherche pour le développement [IRD] : UR206, Centre National de la Recherche Scientifique : UMR7590
Tour 23 - Barre 22-23 - 4e étage - BC 115 4 place Jussieu 75252 PARIS -  France

High-pressure Brillouin [1] and polarized Raman spectra [2] of vitreous silica are measured up to 8 GPa in diamond-anvil cell at room temperature. On one hand, Brillouin frequencies show that the well-known anomalous maximum in the pressure dependence of the compressibility is suppressed by He incorporation into the silica network. This shows that the elastic anomaly relates to the collapse of the largest interstitial voids in the structure. On the other hand, the combined use of either a nonpenetrating pressurizing medium—argon—or a penetrating one—helium and Neon, allows one to separate density from stress effects on the Raman frequencies.

[1] C. Weigel, A. Polian, M. Kint, B. Rufflé, M. Foret, and R. Vacher, Phys. Rev. Lett. 109, 245504 , 2012

[2] C. Weigel, M. Foret, B. Hehlen, M. Kint, S. Clément, A. Polian, R. Vacher, and B. Rufflé, Phys. Rev. B 93, 224303 , 2016


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