In the extended x-ray absorption fine structure (EXAFS) study of the local environment of Bi3+ and Pb2+ ions incorporated in Ba4.5Nd9Ti18O54, actual sites of Bi- and Pb-incorporation are determined. Evidence is given that dopant ions are not distributed randomly on all theoretically possible sites; Bi3+ selectively enters one out of three possible channels, corresponding to the sites x = 0.9484, y = 0.2500, z = 0.2939, and/or x = 0.0455, y = 0.2500, z = 0.6928 previously occupied by Nd3+, while Pb2+ selectively enters site x = 0.4940, y = 0.2500, and z = 0.4993 previously shared by Ba2+ and Nd3+.
ABSTRACTThe local structure around Ba atoms in the compound superconductor Y-Ba-Cu-O has been studied by measuring the extended x-ray absorption fine structure (EXAFS) near the Ba K edge. This technique is used to investigate the changes in the short range order structure when the system is doped with impurities.
Extended X-ray absorption fine structure investigation of Sn local environment in strained and relaxed epitaxial Ge1−xSnx films