Anharmonic versus relaxational sound damping in glasses. II. Vitreous silica

Article

关键词: TEMPERATURE-DEPENDENCE;    ULTRASONIC-ATTENUATION;    STRUCTURAL RELAXATION;    BRILLOUIN-SCATTERING;    THERMAL-CONDUCTIVITY;    ELASTIC PROPERTIES;    ACOUSTIC MODES;    FUSED-SILICA;    QUARTZ;    HEAT;   

DOI  :  10.1103/PhysRevB.72.214205

来源: SCIE

【 摘 要 】

The temperature dependence of the frequency dispersion in the sound velocity and damping of vitreous silica is reanalyzed. Thermally activated relaxation accounts for the sound attenuation observed above 10 K at sonic and ultrasonic frequencies. Its extrapolation to the hypersonic regime reveals that the anharmonic coupling to the thermal bath becomes important in Brillouin-scattering measurements. At 35 GHz and room temperature, the damping due to this anharmonicity is found to be nearly twice that produced by thermally activated relaxation. The analysis also reveals a sizeable velocity increase with temperature which is not related with sound dispersion. A possible explanation is that silica experiences a gradual structural change that already starts well below room temperature.

【 授权许可】

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