Electric Modulus, Scaling and Modeling of Dielectric Properties for Mn2+-Si4+ Co-substituted Mn-Zn Ferrites

The effectiveness of electric modulus in the study of dielectric properties of Mn0.7+xZn0.3SixFe2-2xO4, x = 0.0, 0.1, 0.2 and 0.3 spinel ferrite system as a function of frequency (f = 20 Hz to 1 MHz) and temperature (T = 300-673 K) is investigated. The imaginary part (M '') versus real part (M') of electric modulus (M*) is established to be a preferred representation when compared to epsilon '' versus epsilon' presentation. The values of the stretched exponent parameter indicate the polydispersive nature of dielectric relaxation while the activation energy values suggest that the conduction mechanism and relaxation process are of dissimilar source. The M' and M '', as a function of normalized frequency, form better master curves rather than a function of scaled frequency. The Kohlrausch-Williams-Watts and anomalous diffusion model approaches were employed to fit frequency response curves of M' and M ''.