Frequency Dependence of Dielectric, Conductivity, Impedance and Electrical Modulus Properties of La3+ Substituted in Cobalt- Magnesium Ferrites

Abstract

In this study, structural, morphological, dielectric and AC conductivity properties of CoMgLa ferrite samples (Co0.5Mg0.5LaxFe2-xO4) were investigated according to the change of x (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5). Samples were synthesized by co-precipitation method. The structural properties were examined using XRD and results show that the prepared sample crystallizes in the cubic spinel structure. Crystallite sizes are changing between 24.92 to 9.80 nm. Morphological and elemental properties were analyzed by SEM and EDX. Dielectric properties were investigated by impedance spectroscopy. The samples showed normal dielectric properties consistent with the Maxwell-Wagner model due to interfacial polarization. When the impedance characteristics were examined, it was found that the relaxation process was compatible with the Cole-Cole model. The results of the modulus show that grains contribute to the relaxation process as well as grain boundaries. AC conductivity exhibited semiconductor behavior. The constant behavior of conductivity at low frequencies is a sign that the examined samples may be suitable for many applications.