Acoustic damping and dispersion in vitreous germanium oxide

Guimbretière, Guillaume; Rufflé, Benoît; Vacher, R.

doi:10.1103/physrevb.86.094304

Cited by 6 publications

(5 citation statements)

References 37 publications

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“…6 in [41]. Similar results have been obtained later for some other glasses like GeO 2 [42], B 2 O 3 [43,44], where the boroxol rings were identified as the units subjected to thermally activated relaxations or binary borate glasses [45,46].…”

Section: Ultrasonics and Mechanical Techniquessupporting

confidence: 83%

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Low-frequency vibrational spectroscopy of glasses

Rufflé¹,

Foret²,

Hehlen³

2021

Preprint

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Atomic vibrations in perfect, slightly defective or mixed crystals are to a large extent well understood since many decades. Theoretical descriptions are thus in excellent agreement with the experiments. As a consequence, phonon-related properties like specific heat, thermal conductivity or sound attenuation are also well explained in these solids. This is not yet the case in glasses where the lack of periodicity generates enormous difficulties in theoretical treatments as well as in experiments or in numerical simulations. Thanks to recent developments along all these lines, comprehensive studies have emerged in the last decades and several decisive advances have been made. This chapter is thus devoted to a discussion of the nature of the vibrational properties in glasses with particular emphasis on the low-frequency part of the vibrational density of states, including the acoustic excitations, and of the experimental techniques used to their study.

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Section: Ultrasonics and Mechanical Techniquessupporting

confidence: 83%

“…Figure 7b shows the case of vitreous germania, v-GeO 2 , for which several sound absorption experiments exist at low frequencies ensuring a fair estimate of Q -1 tar . In a nutshell, an analysis similar to that done for v-SiO 2 lead to comparable conclusions [42].…”

Section: Brillouin Light Scatteringmentioning

confidence: 67%

Low-frequency vibrational spectroscopy of glasses

Rufflé¹,

Foret²,

Hehlen³

2021

Preprint

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“…Experimental values of Г( v ), obtained in v-GeO 2 with different techniques (US (refs 22,23), BLS (refs 24,25,26), INS (ref. 24) experiments and MD (ref.…”

Section: Resultsmentioning

confidence: 99%

Acoustic dynamics of network-forming glasses at mesoscopic wavelengths

et al. 2013

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The lack of long-range structural order in amorphous solids induces well known thermodynamic anomalies, which are the manifestation of distinct peculiarities in the vibrational spectrum. Although the impact of such anomalies vanishes in the long wavelength, elastic continuum limit, it dominates at length scales comparable to interatomic distances, implying an intermediate transition regime still poorly understood. Here we report a study of such mesoscopic domains by means of a broadband version of picosecond photo-acoustics, developed to coherently generate and detect hypersonic sound waves in the sub-THz region with unprecedented sampling efficiency. We identify a temperature-dependent fractal v3/2 frequency behaviour of the sound attenuation, pointing to the presence of marginally stable regions and a transition between the two above mentioned limits. The essential features of this behaviour are captured by a theoretical approach based on random spatial variation of the shear modulus, including anharmonic interactions.

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“…Hence, no difference has been observed between both glasses (Figure ). The gradual decrease of ν B for both glasses in (aQ) and (A) states upon heating is a blueprint of anharmonic effects observed in such glass system and other oxide glasses in the gigahertz frequency range. − Our relaxation experiments consisted in a fast temperature rise (50 K/min) from room temperature to a given temperature in the glass transition region, followed by an isothermal annealing where we monitor the relaxation dynamics of the glass by BLS as a function of time. Figure displays a typical time evolution of the Brillouin spectra in the 28.5–32 GHz frequency region for an (aQ) glass during annealing at 686 K. As one can see, Brillouin frequency shows an evolution toward higher frequencies until saturation (Figure ).…”

Section: Resultsmentioning

confidence: 99%

Structural Relaxation Dynamics and Annealing Effects of Sodium Silicate Glass

et al. 2013

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Here we report high-precision measurements of structural relaxation dynamics in the glass transition range at the intermediate and short length scale for a strong sodium silicate glass during long annealing times. We evidence for the first time the heterogeneous dynamics at the intermediate range order by probing the acoustic longitudinal frequency in the GHz region by Brillouin light scattering spectroscopy. Or, from in-situ Raman measurements, we show that relaxation is indeed homogeneous at the interatomic length scale. Our results show that the dynamics at the intermediate range order contains two distinct relaxation time scales, a fast and a slow component, differing by about a 10-fold factor below Tg and approaching to one another past the glass transition. The slow relaxation time agrees with the shear relaxation time, proving that Si-O bond breaking constitutes the primary control of structural relaxation at the intermediate range order.

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Acoustic damping and dispersion in vitreous germanium oxide

Cited by 6 publications

References 37 publications

Low-frequency vibrational spectroscopy of glasses

Low-frequency vibrational spectroscopy of glasses

Acoustic dynamics of network-forming glasses at mesoscopic wavelengths

Structural Relaxation Dynamics and Annealing Effects of Sodium Silicate Glass

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