Electrical properties of SiO2-doped sodium metavanadate sintered discs

Impedance of sintered discs of 0.1, 0.25, 0.4 mol% of sodium metavanadate w as measured in the frequency range 10 kHz-1 MHz and in the temperature regi on from room temperature (= 30 degrees C) to 450 degrees C. AC conductivity was calculated from the data. DC conductivity was measured in the temperat ure range 150-450 degrees C. Debye type of relaxation effects were observed in the dielectric loss. The activation energy of the dipoles involved in r elaxation was estimated. The activation energy for AC conduction in the tem perature above 380 degrees C was calculated. These values are larger than t he activation energy of pure sodium metavanadate sample. The relaxation phe nomenon observed is explained.