Temperature dependence of hypersound attenuation in silica films via picosecond acoustics
| Autor: | FORET, Marie, Huynh, A., Peronne, E., RUFFLE, Benoit, Perrin, B., Lafosse, X., Lemaitre, A., VACHER, Rene |
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| Přispěvatelé: | Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Lifa Zhang (Nanjing Normal University, Conference Chair) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | 16th International Conference on Phonon Scattering in Condensed Matter (Phonons 2018) 16th International Conference on Phonon Scattering in Condensed Matter (Phonons 2018), Lifa Zhang (Nanjing Normal University; Conference Chair), May 2018, Nanjing, China |
| Popis: | We reinvestigate sound dispersion and attenuation in a SiO2 layer as a function of temperature over the range 20–300 K by picosecond acoustics [1]. A pulse-echo scheme is used, where a broadband strain-pulse (centered at 120 GHz) is detected in an Al transducer after propagating back and forth through the SiO2 layer. The acoustic attenuation coefficient α within the SiO2 layer is evaluated by fitting the echoes to a mismatch model including an effective local law for the frequency dependence of attenuation over the band of the pulse. In this way, the T dependence of α in SiO2 layers could be extracted in this work for the first time. Results are found to follow rather well a model combining coupling to thermally activated relaxation mechanisms and interactions with thermal vibrations. This leads to a non-trivial variation of the attenuation coefficient with frequency and temperature. The number density of relaxing defects in the SiO2 layer is found to be slightly higher than that in bulk v-SiO2. In contrast, similar anharmonic contribution to acoustic absorption is observed in both systems. The velocity variations are also measured and are compared to the dynamical velocity changes deduced from the sound attenuation. |
| Databáze: | OpenAIRE |
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