Influence of the microstructure on dielectric and conducting properties of vanadium pentoxide

Abstract

Dielectric and conductivity studies have been performed on compacted powders of vanadium pentoxide V₂O₅ in a broad frequency range 1 kHz–10 GHz, as a function of temperature and density (porosity). The spectra show the existence of relaxation due to grain boundary polarization phenomena. These depend on the synthesis method, i.e., on the microstructure: when the density increases and the average size of the grains decreases the relaxation frequencies increase. Moreover, it has been shown that is possible to determine the real static permittivity and dcconductivity of polycrystalline V₂O₅ by taking account of grain boundaries and porosity effects.