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Titolo:
A study of Raman spectroscopy and low-temperature specific heat in gel-synthesized amorphous silica
Autore:
Bartolotta, A; Carini, G; DAngelo, G; Ferrari, M; Fontana, A; Montagna, M; Rossi, F; Tripodo, G;
Indirizzi:
Univ Messina, Dipartimento Fis, I-98166 Messina, Italy Univ Messina Messina Italy I-98166 artimento Fis, I-98166 Messina, Italy Univ Messina, INFM, I-98166 Messina, Italy Univ Messina Messina Italy I-98166 Messina, INFM, I-98166 Messina, Italy CNR, Ist Tecn Spettroscop, I-98122 Messina, Italy CNR Messina Italy I-98122 , Ist Tecn Spettroscop, I-98122 Messina, Italy CNR, Ctr Fis Stati Aggregati, I-38050 Povo, Trento, Italy CNR Povo TrentoItaly I-38050 tati Aggregati, I-38050 Povo, Trento, Italy Univ Trent, Dipartimento Fis, I-38050 Povo, Trento, Italy Univ Trent PovoTrento Italy I-38050 nto Fis, I-38050 Povo, Trento, Italy Univ Trent, INFM, I-38050 Povo, Trento, Italy Univ Trent Povo Trento Italy I-38050 t, INFM, I-38050 Povo, Trento, Italy
Titolo Testata:
JOURNAL OF NON-CRYSTALLINE SOLIDS
fascicolo: 1-3, volume: 280, anno: 2001,
pagine: 249 - 254
SICI:
0022-3093(200102)280:1-3<249:ASORSA>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
BORATE GLASSES; AEROGELS; EXCITATIONS; SCATTERING; FREQUENCY; DYNAMICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Carini, G Univ Messina, Dipartimento Fis, Contrada Papardo,Salita Sperone 31, I-98166 Messina, Italy Univ Messina Contrada Papardo,Salita Sperone 31 Messina Italy I-98166
Citazione:
A. Bartolotta et al., "A study of Raman spectroscopy and low-temperature specific heat in gel-synthesized amorphous silica", J NON-CRYST, 280(1-3), 2001, pp. 249-254

Abstract

A comparative study of low-temperature specific heat (1.5-25 K), C-p, and low-frequency Raman scattering (< 150 cm(-1)) has been performed in amorphous silica samples synthesized by sol-gel method (xerogels) and thermally densified in a range of densities, from rho = 1250 kg m(-3) to rho = 2100 kg m(-3), close to the density of the melt quenched vitreous silica (v-SiO2). The present analysis concerns the application of the low-energy vibrationaldynamics as an appropriate tool for monitoring the progressive thermal densification of silica gels. By comparison with v-SiO2, the Raman and thermalproperties of xerogels with increasing thermal treatment temperature revealed the following important results: (i) the existence of a critical treatment temperature at about 870 degreesC, where a homogeneous viscous sintering produces full densification of the samples. This effect is detected by the observations of the Boson peak in Raman spectra at about 45 cm(-1) and ofa peak in C-p(T)T (3), very close to those observed in v-SiO2; (ii) in silica xerogels treated at temperatures less than about 800 degreesC, the low-frequency Raman scattering is greater, with a continuous decreasing unstructured shape, and the Boson peak is not detected in the spectra. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 01/10/20 alle ore 16:15:36