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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Network former mixing effects in alkali germanotellurite glasses: A vibrational spectroscopic study

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Tagiara, N. S. [1] ; Chatzipanagis, I, K. ; Bradtmueller, H. [2, 3] ; Rodrigues, A. C. M. [3] ; Moncke, D. [4] ; Kamitsos, I, E.
Total Authors: 6
[1] I, Natl Hellen Res Fdn, Theoret & Phys Chem Inst, 48 Vassileos Constantinou Ave, Athens 11635 - Greece
[2] Westfalische Wilhelms Univ, Inst Phys Chem, Corrensstr 30, D-48149 Munster - Germany
[3] Univ Fed Sao Carlos, Dept Mat Engn, Vitreous Mat Lab, CP 676, BR-13565905 Sao Carlos, SP - Brazil
[4] Alfred Univ, Inamori Sch Engn, New York State Coll Ceram, 1 Saxon Dr, Alfred, NY 14802 - USA
Total Affiliations: 4
Document type: Journal article
Source: Journal of Alloys and Compounds; v. 882, NOV 15 2021.
Web of Science Citations: 0

Alkali germanotellurite glasses of composition 0.3M(2)O-0.7{[}(1-x)GeO2-xTeO(2)], M=Li, Na and 0 <= x <= 1, were investigated by Raman and infrared vibrational spectroscopic techniques to search for the origins of the alkali ion-dependent network former mixing (NFM) effect in these ion-conducting glasses. The vibrational spectra measured on mixed network-former glasses, and the spectral comparison between equimolar-mixed glasses (x = 0.5) and pellet-mixtures of the endmember glasses, 0.3M(2)O-0.7GeO(2) and 0.3M(2)O-0.7TeO(2), provided evidence for the formation of hetero-atomic Ge-O-Te linkages and structural rearrangements in the germanate and tellurite components of the glass. The mixing-induced structural rearrangements were expressed in terms of chemical equilibria between the network-building units and were used to make qualitative predictions for changes in the network cross-linking density and the related network-strain energy, as well as in the binding energy part of the activation energy for ion conduction. Thus, it is proposed that the mixing-induced structural modifications in the germanate and tellurite parts of glass cause the cancelation of changes in the binding energy and the network-strain energy contributions to the activation energy for ion transport. These qualitative predictions were discussed in the context of the previously found absence of an NFM effect in ionic conductivity for M=Na and the presence of a weak positive NFM effect for M=Li. (C) 2021 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 17/02953-6 - Structural study of ionic: transition metal doped phosphate glasses for electrical and non-linear optical applications
Grantee:Ana Candida Martins Rodrigues
Support Opportunities: Research Grants - Visiting Researcher Grant - International
FAPESP's process: 19/26399-3 - Elucidating structural rearrangements during glass relaxation and crystallization
Grantee:Henrik Bradtmüller
Support Opportunities: Scholarships in Brazil - Post-Doctoral