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(114) Production(s) de LE PARC R.
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Pressure-induced amorphization in the GeTe-Sb$_2$Te$_3$ (GST) system: implication for phase change optical
recording''
Auteur(s): Haines Julien, Kolobov Alex, Ribes Michel, Fons Paul, Tominaga J., Katayama X, Hammouda Tahar, Steiner X, Wuttig X, Aquilanti G., Pascarelli S, Le Parc R., Levelut C.
Conference: Joint 21st AIRAPT and 45th EHPRG International Conference on High Pressure Science and Technology (catania, IT, 2007-09-17)
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Pressure-induced phase transitions in phosphate-like $\alpha$-quartz-type solid solutions
Auteur(s): Haines Julien, Cambon Olivier, Le Parc R., Levelut C., Pereira Altair
Conference: 24th European Crystallographic meeting (marrakech, MA, 2007-08-22)
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Density fluctuations in oxide glasses investigated by small-angle X-ray scattering
Auteur(s): Levelut C., Le Parc R., Faivre A., Brüning Ralf, Champagnon Bernard, Martinez V., Simon J., Bley Françoise, Hazemann Jean-Louis
(Article) Publié:
Journal Of Applied Crystallography, vol. 40 p.s512-s516 (2007)
Texte intégral en Openaccess :
Ref HAL: hal-00175448_v1
DOI: 10.1107/S0021889807000507
WoS: 000246059800103
Exporter : BibTex | endNote
16 Citations
Résumé: The structure of glasses is characterized by the existence of density and composition fluctuations on the nanometre scale. We present three examples of the use of small-angle X-ray scattering to get information about these density fluctuations. The thermal history and OH content were observed to have a huge influence. The static compressibility decreases when the OH content or fictive temperature increase. We showed that temperature scanning small-angle X-ray scattering can provide an accurate description of the position, width and shape of the glass transition.
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Density fluctuations in oxide glasses investigated by SAXS
Auteur(s): Levelut C., Le Parc R., Faivre A., Brüning R., Champagnon B., Martinez V., Simon J., Bley F., Hazemann J.L.
(Article) Publié:
Journal Of Applied Crystallography, vol. 40 p.S512-S516 (2007)
Ref HAL: hal-00504416_v1
Exporter : BibTex | endNote
Résumé: The structure of glasses is characterized by the existence of density and composition fluctuations on the nanometre scale. We present three examples of the use of small-angle X-ray scattering to get information about these density fluctuations. The thermal history and OH content were observed to have a huge influence. The static compressibility decreases when the OH content or fictive temperature increase. We showed that temperature scanning small-angle X-ray scattering can provide an accurate description of the position, width and shape of the glass transition.
Commentaires: Suppl. 1
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In situ X-ray powder diffraction study of one-dimensional polymeric C60 phase transformation under high-pressure
Auteur(s): Le Parc R., Levelut C., Haines Julien, Davydov V. A., Rakhmanina A. V., Papoular R. J., Belova E. E., Chernozatonskii L. A., Allouchi H., Agafonov V.
(Article) Publié:
Chemical Physics Letters, vol. 438 p.63-66 (2007)
Texte intégral en Openaccess :
Ref HAL: hal-00175435_v1
DOI: 10.1016/j.cplett.2007.02.055
WoS: 000245776300012
Exporter : BibTex | endNote
14 Citations
Résumé: Pressure dependence of the orthorhombic polymeric phase of C60 has been studied by angle-dispersive, X-ray powder diffraction in a diamond anvil cell. Transformation to a new phase through the simultaneous action of pressure and X-rays was observed between 0.2 and 1.66 GPa. A possible structure of this new phase of C60 is discussed. Further increase in pressure leads gradually to the irreversible formation of a disordered phase.
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The effect of static disorder on pressure-induced phase transitions and amorphization in α-quartz-type solid solutions
Auteur(s): Haines Julien, Cambon Olivier, Le Parc R., Levelut C.
(Article) Publié:
Phase Transitions A Multinational Journal, vol. 80 p.1039-1049 (2007)
Ref HAL: hal-00179625_v1
DOI: 10.1080/01411590701473085
WoS: 000251117100005
Exporter : BibTex | endNote
5 Citations
Résumé: The high-pressure stability of agr-quartz-type materials is of considerable interest for materials (piezoelectrics etc.) and Earth science. Representative compositions of two agr-quartz type solid solutions SiO2-PON and AlPO4-GaPO4 were studied at high pressure by X-ray diffraction. These materials exhibit distinct high pressure behaviour as the diffraction lines of agr-quartz-type Si0.56P0.44O1.56N0.44 were found to decrease in intensity above 23 GPa with the pattern becoming completely featureless above 40 GPa, whereas Al0.30Ga0.70PO4 transforms to a poorly-crystallised phase above 12 GPa. This difference in behaviour can be linked to the initial degree of positional disorder in the two solid solutions. A highly disordered, possibly amorphous, phase is favoured in the SiO2-PON system, in which positional disorder is present on all cation and anion sites. In contrast, disorder affects only frac12 of the cation sites in the AlPO4-GaPO4 system. A high degree of disorder, particularly on the site occupied by phosphorus, plays a role in inhibiting the formation of ordered phases with increased cation coordination.
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Density and density fluctuations anomalies of SiO2 glass: comparison and light-scattering study
Auteur(s): Champagnon Bernard, Martinez V., Martinet Christine, Le Parc R., Levelut C.
(Article) Publié:
Philosophical Magazine B, vol. 87 p.691-695 (2007)
Ref HAL: hal-00175421_v1
DOI: 10.1080/14786430601032345
WoS: 000244150900040
Exporter : BibTex | endNote
10 Citations
Résumé: he objective of this work is to compare density and density fluctuations of silica as a function of temperature in the anomalous domain between 950 and 1480°C via Archimedes' macroscopic measurements and light scattering. Parallel qualitative behaviour is also recorded between density fluctuations and macroscopic density. Density fluctuations of silica show a minimum as a function of temperature, as with macroscopic density. This correlation indicates a possible common origin of both observations.
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