X-ray analysis of GeSeAg glasses

Glass sample of the (Ge Se-3)(100-x)Ag-x system were prepared in the compos ition range from x = 0 to x = 25 at.%. Short range order (SRO) was examined by X-ray diffraction using Mo(K alpha) radiation at room temperature. X-ra y scattering curves have a first scattering peak (FSP) located at q approxi mate to 1 Angstrom(-1). FSP has a systematic increase in intensity with dec reasing Ag concentration revealing a change of the intermediate range order (IRO). The coordination numbers and the bond Lengths of the correlation Ge -Se. Se-Se, Se-Ag, and Ag-Ag as a function of composition are determined fr om the radial distribution function. The experimental data an contrasted wi th a structure proposed for the glass. The fundamental structural unit of t he glass is the Ge-Se-4/2 tetrahedra. The present results are also compared with other authors. (C) 2000 Elsevier Science B.V. All rights reserved.