Thermoelectric-Power Studies of Bismuth Based Oxides

This report describes measurements of thermoelectric power of bismuth vanadium oxide, Bi4V2O11, three samples of Cu2+ doped bismuth vanadium oxide, Bi2V0.95Cu0.05O5.425, Bi2V0.925Cu0.075O5.3875 and Bi2V0.9Cu0.1O5.35. For these oxides reversible oxygen electrodes were employed which enabled very accurate measurements to be made. Conductivity measurements were also carried out as a comparison to the thermoelectric power results. In addition, EXAFS and high temperature, powder XRD experiments were performed on the samples to investigate any structural phase changes in combination with the electrical studies

A High-Temperature XAFS Study of the Iron-Oxides

Results are reported of a high-temperature XAFS study of the three iron oxides wustite, FeO, magnetite, Fe3O4, and hematite, Fe2O3. The in-situ experiments have been performed at temperatures up to 1200 degrees C using oxygen partial pressures appropriate to the stability fields of the three oxides. The spectra provide information on a variety of high-temperature properties of these compounds. The present contribution focuses on the defect structure of nonstoichiometric wustite, FeO