Complex impedance and electric modulus studies of Al substituted Co0.4Cu0.2Zn0.4AlxFe2-xO4 ferrites prepared by auto combustion technique

摘要

Al substituted Co0.4Cu0.2Zn0.4AlxFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) ferrites have been prepared using auto combustion route. X-ray diffraction studies revealed the formation of single phase spinel type cubical structure. The dielectric properties of the samples at room temperature have been studied over the frequency range of 20Hz to 15MHz. The dielectric constant and loss tangent is found to decrease with increasing Al content. Dielectric spectra analysis and modulus show the non-Debye type behavior in the material. Complex impedance spectra of the samples have been analyzed and explained using the Cole-Cole expression. The complex impedance data are indicative of the dominance of grain boundary resistance. AC conductivity has a trend to decrease with Al content and a shift of hopping frequency towards lower frequency is also observed.