Effect of co-substitution of Co-Zr on electromagnetic properties of Ni-Zn spinel ferrites at microwave frequencies

The comprehensive study of the effect of substitution of cobalt and zirconium in nickel-zinc spinel ferrites is presented. Ni0.6Zn0.4(CoZr)(x)Fe2-2xO4 ferrites have been successfully synthesized with sol-gel citrate precursor route with x varying from 0.05 to 0.25 in steps of 0.05. The X-ray diffraction patterns confirm the cubic spinel structure of the ferrites. The lattice constant is found to increase whereas porosity of the samples is found to decrease with the level of substitution. High dielectric and magnetic losses are exhibited by the substituted samples. A minimum reflection loss of -44.92 dB and -40.43 dB are obtained for compositions x = 0.20 and x = 0.25 respectively at a matching thickness of 4.25 mm in X band. These materials prove to be good microwave absorbers in the studied frequency band. (C) 2020 Published by Elsevier B.V.