Accueil >
Production scientifique
Physique des Verres
(24) Production(s) de l'année 2016
|
|
Relaxor Ferroelectrics: Back to the Single-Soft-Mode Picture. 
Auteur(s): Hehlen B., Al Majzoub Al Sabbagh M., Al-Zein A., Hlinka J
(Article) Publié:
Physical Review Letters, vol. 117 p.155501 (2016)
Texte intégral en Openaccess : 
Ref HAL: hal-01388588_v1
PMID 27768376
DOI: 10.1103/PhysRevLett.117.155501
WoS: 000385341900016
Exporter : BibTex | endNote
15 Citations
Résumé: The fluctuations of electric polarization in a disordered ferroelectric substance, relaxor crystal PbMg_{1/3}Nb_{2/3}O_{3} (PMN), were studied using a nonlinear inelastic light-scattering technique, hyper-Raman scattering, within a 5-100 cm^{-1} spectral interval and in a broad temperature range from 20 to 900 K. The split ferroelectric mode reveals a local anisotropy of up to about 400 K. Spectral anomalies observed at higher temperatures are explained as due to avoided crossing of the single primary polar soft mode with a temperature-independent, nonpolar spectral feature near 45 cm^{-1}, known from Raman scattering. The temperature changes of the vibrational modes involved in the measured fluctuation spectra of PMN were captured in a simple model that accounts for the temperature dependence of the dielectric permittivity as well. The observed slowing down of the relaxational dynamics directly correlates with the huge increase of the dielectric permittivity.
|
|
|
|
Elastic Constants, Optical Phonons, and Molecular Relaxations in the High Temperature Plastic Phase of the CH3NH3PbBr3 Hybrid Perovskite.
Auteur(s): Létoublon Antoine, Paofai Serge, Ruffle B., Bourges Philippe, Hehlen B., Michel T., Ecolivet Claude, Durand Olivier, Cordier Stéphane, Katan Claudine, Even Jacky
(Article) Publié:
Journal Of Physical Chemistry Letters, vol. 7 p.3776-3784 (2016)
Texte intégral en Openaccess : 
|
|
|
|
Elasticity of vitreous silica under fluid pressure
Auteur(s): Weigel C., Foret M., Kint M., Vacher R., Ruffle B. , Polian Alain, Rouquette Jérome, Haines Julien, Coasne Benoit
Conference: Glass & Optical Materials Division Annual Meeting 2016 (Madison (WI), US, 2016-05-26)
|
|
|
|
Polarized Raman spectroscopy of v-SiO2 under rare-gas compression
Auteur(s): Weigel C., Foret M., Hehlen B., Kint M., Clement S., Polian Alain, Vacher R., Ruffle B.
(Article) Publié:
Physical Review B, vol. 93 p.224303 (2016)
Ref HAL: hal-01337959_v1
DOI: 10.1103/PhysRevB.93.224303
WoS: 000378104200007
Exporter : BibTex | endNote
13 Citations
Résumé: High-pressure polarized Raman spectra of vitreous silica are measured up to 8 GPa in a diamond-anvil cell atroom temperature. The combined use of either a nonpenetrating pressurizing medium—argon—or a penetrating one—helium, allows one to separate density from stress effects on the Raman frequencies. In the framework of a simple central force model, the results emphasize the distinct role played by the shrinkage of the intertetrahedral angle Si-O-Si and the force-constant stiffening during the compression. The polarization analysis further reveals the existence of an additional isotropic component in the high-frequency wing of the boson peak. The pressure dependence of the genuine boson peak frequency is found to be much weaker than previously reported and even goes through a minimum around 2 GPa in remarkable coincidence with the anomalous compressibility maximum of silica.
|
|
|
|
Elastic moduli of XAlSiO4 aluminosilicate glasses: effects of charge-balancing cations
Auteur(s): Weigel C., Le Losq Charles, Vialla R., Dupas C., Clement S., Neuville D. R., Ruffle B.
(Article) Publié:
Journal Of Non-Crystalline Solids, vol. 447 p.267-272 (2016)
Ref HAL: hal-01337905_v1
DOI: 10.1016/j.jnoncrysol.2016.06.023
WoS: 000381841200040
Exporter : BibTex | endNote
17 Citations
Résumé: Brillouin spectroscopy is used to investigate the elastic properties of XAlSiO4 aluminosilicate glasses where X =Li, Na, K, Mg0.5, Ca0.5, Sr0.5, Ba0.5, and Zn0.5. The Brillouin frequency shifts obtained in two different scattering geometries allow the calculation of the refractive index, the two sound velocities and Poisson's ratio.Measurements of the mass density give in turn the elastic moduli and the Debye temperature.We find that the elastic properties scale with the atomic density of the glassy network or the charge-balancing cation field strengthwhile they negatively correlate with the glass transition temperature. Further, Poisson's ratio depends on the nature of the non-framework cations in this glass series.
|
