The variation of real and imaginary parts of electric modulus for different contents of silica is shown in Figs. 6(a) and (b). The long tail appearing in the low frequency region of M0 is an evidence of almost complete removal of the electrode polarization effects. The presence of peaks in the modulus formalism is an ample evidence of the prevalence of ionic species as charge carriers in the system. The peaks in the M0 spectra are attributed to the bulk effect which in
turn appears due to the heterogeneity in texture[39]. The presence of peaks in the M00 spectra are a signature of conductivity relaxation of the material [40]. It can be observed from the M00 spectra that the height of the peaks gradually decreases as the silica content increases. This behavior is a signature of plurality of relaxation mechanism [41].