Theoretical investigation of some experimental data of Al-substituted MnZn spinel ferrites

Master curve generation and modeling of ac conductivity for Mn0.7+xZn0.3SixFe2–2xO4 spinel ferrite system

“…11 It can be seen that the scaling process shows very limited success in the low-frequency range. The unsuccessful mastering process of ′ at low frequency as in the present case was also observed earlier by Saafan et al 23 for Al-substituted Mn-Zn ferrites. They attributed it to the existence of positive charge carriers whose thermal dependence cannot be eliminated by scaling x-axis by either dc or f max .…”

“…This is expected based on the fact that dc and f max are characteristic values concerned with the electrons' motion and do not involve any information about motion of positive charge carriers. 23 For the system under study, 20 Thus, we expect that the motion of holes (positive charge carriers) as minority charge carriers or polaron hopping is not revealed in dc values which are responsible factors for the unsuccessful master curve generation. Rolling et al 24 suggested that dc and dc T can be used as the scaling parameters for the conductivity and frequency axes, respectively.…”

“…The experimental data of ac conductivity ( ac Þ was attempted to fit with Dyre's macroscopic model in its two approximations, PPA and effective medium approximation (EMA), based on the relationship equations established by Saafan et al 23 for spinel ferrite system. These two approximations are well discussed in Ref.…”

Dielectric properties and scaling behavior of lithium tungsten phosphate glasses

“…where M′ and M″ are the real and imaginary parts of the complex modulus M* Saafan et al [34] investigated the Cole-Cole diagrams of both M″ vs. M′ at different temperatures; they found that these diagrams are suitable way for representation of the experimental data. They concluded that the Cole-Cole diagrams, the one giving a master semicircular curve for all temperatures and it will also be an indication to the property that is dominating in the studied glass.…”

“…Now, it happens frequently that the great majority of practical situations involve the electric field as the independent variable, and accordingly equation (13) is applicable. There are only relatively few situations where the opposite is the case in [34]. One such example is the motion of space charge ρ v in a dielectric system where the resulting D field is directly related through:…”