Neutron diffraction studies of Ag₂S–As₂S₃ glasses in the percolation and modifier-controlled domains

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• 作者：Bychkov ; E. ; Price ; D.L.
• 刊名：Solid State Ionics
• 出版年：2000
• 出版时间：November 2, 2000
• 年：2000
• 卷：136-137
• 期：Complete
• 页码：1041-1048
• 全文大小：464 K

文摘

High-resolution neutron diffraction experiments at scattering vectors up to 40 Å⁻¹ have been carried out for the Ag₂S–As₂S₃ glassy system in order to find differences in the network structural organisation within the percolation and modifier-controlled domains. No significant changes in the short- and intermediate-range order are found in the critical percolation region (x≤1.2 at. % Ag): the intensity and position of the first sharp diffraction peak (FSDP) exhibit relatively small changes as a function of the silver content, and the trigonal arsenic local coordination and two-fold coordinated sulphur species remain essentially intact. These observations agree very well with a model of host network-dependent percolative ion transport. In the modifier-controlled domain (x>10–15 at. % Ag), one observes nearly complete disappearance of the FSDP at 1.25–1.35 Å⁻¹ and remarkable changes in the short-range order, in particular, characteristic Ag–Ag correlations at 3 Å, indicating a predominant role of Ag-containing structural units in the modified network organisation. These structural units and their interconnections seem to be similar for many silver-rich chalcogenide glasses, in which the Ag⁺ ion transport depends on the Ag content but not on the host matrix.