Effect of Cr substitution on structural, magnetic and impedance spectroscopic properties of Cd0.5Zn0.5Fe2-xCrxO4 ferrites

Cr-substituted Cd-Zn spinel ferrites of different compositions (Cd0.5Zn0.5Fe2-xCrxO4) were prepared using solgel method for x = 0 and 0.5. The XRD analysis and Rietveld refinements indicate that samples crystallize in the cubic Fd3 over bar m spinel structure and the lattice parameters decrease with Cr substitution. Two principal absorption bands related to the stretching vibration of tetrahedral and octahedral sites were shown from FTIR spectra. The spontaneous magnetization, coercivity and remanance were also investigated for the prepared samples. DC conductivity was found to decrease with the substitution of Cr. The studies of imaginary part of permittivity and tangent loss reveal that the prepared materials may be good candidates for some interesting electronics devices. An electrical relaxation phenomenon with non-Debye nature was observed from the variations of imaginary parts of modulus and impedance. The estimated activation energies values from relaxation time and dc-conductivity are very close. Electrical parameters deduced from the Nyquist plots using an equivalent circuit show that the conduction process in the prepared samples is due to the grain boundaries contributions.