Diffuse neutron scattering from ordered phase of Ag3SI at 128 K

The existence of an oscillatory diffuse scattering from the ordered gamma-p hase of superionic conductor Ag3SI has been confirmed by neutron scattering measurement at 128 K. A newly proposed generalized background function, wh ich includes the correlation between the thermal displacements of atoms, ha s been applied in the Rietveld analysis. The results give a better fit to t he observed background intensities. This result may suggest that the main c ontribution to the oscillatory diffuse scattering of ordered gamma-Ag3SI ma inly originates from strong correlation among the displacements of silver a nd iodine atoms. (C) 1998 Elsevier Science Ltd. All rights reserved.