Electrical properties of SiO2-doped sodium metavanadate sintered discs

Impedance of sintered discs of 0.1, 0.25, 0.4 mol% of sodium metavanadate was measured in the frequency range 10 kHz- 1MHz and in the temperature region from room temperature (= 30 deg C) to 450 deg C. AC conductivity was calculated from the data. DC conductivity was measured in the temperature range 150-450 deg C. Debye type of relaxation effects were observed in the dielectric loss. The activation energy of the dipoles involved in relaxation was estimated. The activation energy for AC conduction in the temperature above 380 deg C was calculated. These values are larger than the activation energy of pure sodium metavanadate sample. The relaxation phenomenon observed is explained. (author)