Network former mixing (NFM) effects in alkali germanotellurite glasses

Autor(es)

Bradtmueller, Henrik ; Rodrigues, Ana Candida Martins ; Eckert, Hellmut

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 873, p. 9-pg., 2021-04-17.

Resumo

Network former mixing (NFM) effects on ionic conductivities have been characterized in ternary germa-notellurite glasses of composition (A(2)O)(0.3)[(TeO2)(x)(GeO2)(1-x)](0.7) (A = Li, Na), revealing an interesting cation dependence. While the results demonstrate a weak positive NFM effect in the Li-containing system, the electrical conductivities of the Na-containing systems correspond to the weighted average values observed in their binary endmembers. The structural origins of these differing effects have been explored by Raman scattering and Te-125 solid-state NMR spectroscopy, indicating no significant differences in the structural organization of these materials. Overall, the data suggest that the concentration of heteroatomic con-nectivities is relatively low. For the Li-containing system, an analysis of the motional narrowing effects observed in temperature-dependent static Li-7 NMR spectra confirms the existence of a weak positive NFM effect at the local atomic level. Accordingly, the absence of an NFM effect for the Na-containing system is corroborated by low-temperature Na-23 spin-echo decay spectroscopy, showing very similar network modifier distributions in those glasses. (C) 2021 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs