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].