Structure-transport Correlation of Mixed Network Former Glasses

Reference Presenter Authors
10-028 Aswini Ghosh Ghosh, A.(Indian Association for the Cultivation of Science); Palui, A.(Indian Association for the Cultivation of Science); The study of the transport properties of glassy ionic conductors and their correlation with the glass network structure is a challenging problem as the microscopic network structure controls the ion transport mechanism in these glasses [1, 2]. In our present work we have studied the dynamics of Ag+ ions in different mixed network former glasses (SeO2, MoO3 and TeO2 are used as glass formers) for wide composition and temperature ranges. We have measured the conductivity spectra of the glasses in wide frequency and temperature ranges. Non-liner variation of the conductivity has been observed with variation of mixed former ratio. Using linear response theory, we have calculated mean square displacement of mobile Ag+ ions as a function of time and obtained the characteristic mean square displacement at time tp, where the transition from dispersive to non-dispersive behavior of occurs. Compositional dependence of ? is opposite to that of the conductivity. We have also measured FTIR spectra of these glasses and obtained the relative strength of different structural units SeO32-, TeO4, etc. constituting the glass network. We have shown that is strongly correlated to the strength of these structural units. The increase of modifier oxide preferentially breaks the glass network structure leading to de-polymerization of the glass network, which in turn leads to the increase of non-bridging oxygen [3, 4]. From scaling of the conductivity spectra it has been revealed that the ion conduction mechanism is independent of temperature as well as composition. The present work is highly important in order to achieve a deeper understanding of the ion transport mechanisms in glasses. 
[1] A. Palui, A. Shaw, A. Ghosh, Phys. Chem. Chem. Phys., 18 (2016) 25937. 
[2] A. Palui, A. Ghosh, J. Phys. Chem. C, 121 (2017) 8738-8745. 
[3] B. Deb, A. Ghosh, J. Appl. Phys., 112 (2012) 094110. 
[4] A. Palui, A. Ghosh, J. Appl. Phys., 121 (2017) 125104.
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