INFLUENCE OF THE MICROSTRUCTURE ON DIELECTRIC AND CONDUCTING PROPERTIES OF VANADIUM PENTOXIDE

Dielectric and conductivity studies have been performed on compacted p owders 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 ph enomena. These depend on the synthesis method, i.e., on the microstruc ture: when the density increases and the average size of the grains de creases the relaxation frequencies increase. Moreover, it has been sho wn that is possible to determine the real static permittivity and dc-c onductivity of polycrystalline V2O5 by taking account of grain boundar ies and porosity effects.