EXAFS AND RAMAN STUDIES OF DYSPROSIUM DOPED SODIUM SULFATES

Results of Raman, conductivity and EXAFS studies of dysprosium doped sodium sulfates at concentrations of 0.5% and 3% of Dy3+ are presented. The Raman studies show that the lower dopant level (0.5% mole of Dy3+) produces the phase III structure whereas the higher doping (3% mole of Dy 3+) results in a change to the phase I form. The conductivity increases with dopant level. The EXAFS results, which probe the immediate local environment of the dopant ion, show that the nearest neighbor shells for the two structures are almost identical and only subtle differences can be seen in the second nearest neighbor shells. This is consistent with the concept that it is the number rather than nature of the dopant ion that influences the phase stabilization process. The EXAFS studies also showed the absence of dysprosium clustering. These studies confirm the complementary nature of the Raman and EXAFS techniques, the former probing the host structure and the latter addressing the local dopant ion environment. © 1994 American Institute of Physics.