The acoustic attenuation of vitreous germania (v-GeO2) has been measured over more than three decades in frequency, by means of neutron scattering at high-frequency (THz), visible light scattering and the newly developed technique of Brillouin ultraviolet scattering at lower frequencies (15-50 GHz). The experiments are supported by a molecular dynamics study of a simulated sample of v-GeO2. The temperature dependence, from 80 K up to the glass transition temperature, shows a persistence of the dynamical nature of the attenuation in the GHz range and a simultaneous increase of the contribution coming from the structural disorder. At higher frequencies clear evidences of a crossover to a region where the attenuation is induced only by the topological disorder are found. © Europhysics Letters Association.
Dynamic-to-static crossover in the acoustic attenuation of v-GeO 2 / Baldi, G.; Benassi, P.; Bove, L. E.; Caponi, S.; Fabiani, E.; Fioretto, D.; Fontana, A.; Giugni, A.; Nardone, M.; Sampoli, M.; Scarponi, F.. - In: EUROPHYSICS LETTERS. - ISSN 0295-5075. - 78:3(2007), p. 36001. [10.1209/0295-5075/78/36001]
Dynamic-to-static crossover in the acoustic attenuation of v-GeO 2
Bove L. E.;
2007
Abstract
The acoustic attenuation of vitreous germania (v-GeO2) has been measured over more than three decades in frequency, by means of neutron scattering at high-frequency (THz), visible light scattering and the newly developed technique of Brillouin ultraviolet scattering at lower frequencies (15-50 GHz). The experiments are supported by a molecular dynamics study of a simulated sample of v-GeO2. The temperature dependence, from 80 K up to the glass transition temperature, shows a persistence of the dynamical nature of the attenuation in the GHz range and a simultaneous increase of the contribution coming from the structural disorder. At higher frequencies clear evidences of a crossover to a region where the attenuation is induced only by the topological disorder are found. © Europhysics Letters Association.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.