Session L27: Glassy Systems
2:30 PM–5:06 PM, Tuesday, March 6, 2007
Colorado Convention Center Room: 301
Sponsoring Unit:
DCMP
Chair: Dimitrios Papaconstantopoulos, George Mason University
Abstract ID: BAPS.2007.MAR.L27.13
Abstract: L27.00013 : Conductivity thresholds and glass structure in (K$_{2}$O)$_{x}$(GeO$_{2}$)$_{1-x}$ glasses
4:54 PM–5:06 PM
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Abstract
Authors:
Ninghua Wang
(University of Cincinnati)
Deassy Novita
(University of Cincinnati)
Punit Boolchand
(University of Cincinnati)
There are reports of conductivity thresholds with glass composition in solid electrolyte glasses. In the titled glass system, a seven order of magnitude increase in conductivity\footnote{Jain et al JNCS 222, 361 (1997).} occurs at x $>$ 0.10. The origin of the observation remains an open question. In titled glasses, we show that glass structure probed by the elastic behavior of its backbone shows two thresholds, a stress transition near x = 0.04 and a rigidity transition near x = 0.09. These elastic thresholds emerge from the reversibility window\footnote{S. Chakravarty et al. J.C.M.P 17,L1-7 (2005).} observed in calorimetric measurements, and in Raman scattering experiments that show scattering strength of the 520 cm$^{-1}$ mode of 3-member rings to show a global maximum in the reversibility window. The pronounced increase of conductivity apparently occurs when backbones become flexible at x $>$ 0.09, permitting K$^{+}$ ions to freely diffuse. The correlation between the electrical, thermal and optical properties of the present solid electrolyte glasses may well be a generic feature of these materials.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.MAR.L27.13