The silver fast-ion conductor (LaO)AgS was examined in temperature-dependen
t so impedance and time-of-Right neutron diffraction experiments. Compariso
n of our conductivity data with those published earlier suggests that the p
resence of unreacted Ag2S resulting From different sample preparation metho
ds is the possible reason for severe discrepancies in the conductivity data
of other authors. Anisotropic temperature factors obtained by Rietveld ana
lysis of our neutron diffraction data indicate enhanced silver ion mobility
in the a-b plane of the tetragonal structure. The observed silver ion dens
ity shows that the preferred conduction path is via interstitial (1/2 1/2 1
/2) sites, i.e. along < 110 >. (LaO)AgS is a two-dimensional silver fast-io
n conductor. (C) 2000 Elsevier Science B.V. All rights reserved.