Mean-coordination number dependence of the fragility in Ge–Se–In glass-forming liquids
نویسنده
چکیده
Differential scanning calorimetry measurements have been performed on elemental Se as well as on GexSe94 xIn6 (x 1⁄4 4, 8, and 11 at%) and on GeySe88 yIn12 (y 1⁄4 5, 7, and 9 at%) chalcogenide glasses. From the cooling rate dependence of the fictive temperature, the apparent activation energies, Dh*, and the fragility indices, m, as defined in the strong–fragile glass-forming liquid concept, are determined. It is found that, in Ge–Se–In system, there is an evolution from strong (m 1⁄4 67) to fragile (m 1⁄4 116) glass-forming liquids. The dependence of ‘m’ on the mean-coordination number, Z, is also obtained. This dependence is rationalized by assuming that, in this glassy alloy system, there is a tendency for the formation of In2Se3 clusters. r 2006 Elsevier B.V. All rights reserved. PACS: 61.43.Fs; 64.70.Pf; 65.60.+a
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