Reverse Monte-Carlo Analysis of neutron diffraction from AgI–Ag2S–AgPO3 superionic conducting glasses

Neutron diffraction patterns from silver phosphate (AgPO3), AgI–AgPO3 and Ag2S–AgPO3 glasses were analysed by the Reverse Monte-Carlo method. The diffraction patterns were collected on the HIT-II spectrometer at KENS up to Q=50Å-1. The derived structural models of the salt-doped glasses were compared to AgPO3 glass to correlate features of the atomic and molecular structure with observed superionic conduction in these glasses.A structural model based on extended chains of PO4 tetrahedra, as reported previously by other researchers, provides a solid basis for all these glasses. The analysis indicates a strengthening of the Ag–Ag correlations and contrasting changes in the Ag–O correlations in the doped glasses. We also conclude that S largely displaces non-bridging O in the PO4 tetrahedra in Ag2S–AgPO3 glass.