There is an apparent contradiction between the predictions of Mott-theory and experimental conductivity data of vanadium phosphate glasses. In parallel investigations we measured the molar volume of V2O5-P2O5 glasses with 55, 60, 70, 75 and 85 mol % V2O5 systematically varying the vanadium valence state, and characterized their microstructure by SEM, TEM and EDAX. We demonstrate that phase separation is a characteristic feature of this glass system and there is a compositional gradient at phase boundaries. It is suggested that amorphous V2O5−x/O<x<1/ films prepared by chemical vapour deposition can be appropriate prototype materials for testing the predictions of polaron theory for conduction.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry