Rietveld Neutron Powder Profile Analysis and Electrical Conductivity of the Fast Silver-Ion Conductor (LaO)AgS

摘要

Lanthanum silver oxysulfide, (LaO)AgS, exhibits a predominantly ionic ocnductivity of 10~(-3) to 10~(-1) S/cm between 300 K and 770K. The tetragonal structure consists of alternation and sheets, their sequence being O-La-S-Ag-S-La-O. The structure suggests that ionic transport arises from migration of silver ions within the AgS layers analogous to sodium ion transport in Na-#beta#-alumina. Neutron powder diffraction data measured at five temepratures between 300 k and 770K are analysed using the Rietveld method to determine the distribution and thermla vibration parameters of the mobile silver ions. The structural investigation is accompanied by measurements of the total conductivity in the same temperature range in order to resolve severe discrepancies in the literature data.