Transverse phonons and intermediate-range order in Sr-Mg fluorophosphate glasses

Vibrational and ultrasonic spectroscopies have been employed to study the composition and polarization dependence of the vibrational and elastic properties of the pseudo-binary mixed fluoride-phosphate glass-forming system xSr(PO3)2-(1-x)(0.62MgF2-0.38AlF3) with x: 0, 0.04, 0.06, 0.1, 0.15, 0.2, 0.3...

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Bibliographic Details
Published in:Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2019-04, Vol.212, p.363-370
Main Authors: Mpourazanis, P., Stogiannidis, G., Tsigoias, S., Kalampounias, A.G.
Format: Article
Language:English
Subjects:
Amorphous materials
ATR spectroscopy
Boson peak
Elastic properties
Oxide glasses
Phonons
Raman spectroscopy
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Summary:Vibrational and ultrasonic spectroscopies have been employed to study the composition and polarization dependence of the vibrational and elastic properties of the pseudo-binary mixed fluoride-phosphate glass-forming system xSr(PO3)2-(1-x)(0.62MgF2-0.38AlF3) with x: 0, 0.04, 0.06, 0.1, 0.15, 0.2, 0.3, 0.4, 0.8, 0.9 and 1. Composition-induced alterations in the short-range order have been quantitatively followed by means of Raman and IR spectroscopies. The analysis has shown that the incorporation of the phosphate groups in the fluoride network results in a less interconnected network with suppressed rigidity. The specific amorphous materials have been used as a model system in terms of wide glass-forming ability to elucidate the effect of variation in connectivity between the fluoride and phosphate sub-networks on the Boson peak nature. Emphasis has been given in the low-frequency Raman phenomenology, which in conjunction with the elastic properties allowed us to establish a possible link between the Boson peak and the transverse phonons in these glasses. [Display omitted] •Fluorophosphate structure becomes less interconnected with increasing phosphate content.•Incorporation of phosphate groups in fluoride network results in chain-to-ring conversion.•Boson frequency shows strong linear dependency on molar volume and shear modulus.•Boson peak intensity found to be inversely proportional to shear modulus.•Boson peak variation can be described regarding transformation of the elastic medium.
ISSN:1386-1425
DOI:10.1016/j.saa.2019.01.024