Abstract:

We have studied, by Raman spectroscopy, materials H1-xAgxTaWO6 and KTaWO6, both belonging to the pyrochlore system whose symmetry Fd3m (Oh7). The experiments consisted in measurements of the Raman spectrum, at room temperature, on samples, before and after heat treatment. We have not performed photoinduced transformations studies on samples subjected to strong illumination. Instead of, we performed the heat treatment temperature of 700 °C, where the transition phase takes place. Studies using the Group Theory were performed to describe the changes observed in the spectra as a function of heat treatment at different temperatures. Through these studies, along with a comparison with information in the literature, it was possible to better understand the thermal stability of the material. Our studies showing by both Raman spectroscopy and DSC/TG techniques there was not significant loss of mass. It means the samples may have performed transitions to defective pyrochlore phase.