Effect of cobalt substitution on electromagnetic response of Manganese-Zinc spinel ferrite composite

In this study, cobalt doped Manganese-Zinc ferrites ${\mathrm{Mn}}_{0.5}{\mathrm{Zn}}_{0.5-x}{\mathrm{Co}}_x{\mathrm{Fe}}_2{O}_4$ as $x=0,0.1,0.2,0.3,0.4$ are synthesized using the sol–gel auto-combustion method. Structural study of as-prepared samples is done using X-ray diffraction and confirms the formation of single-phase cubic spinel structure of the undoped sample. The effect of cobalt doping is observed in XRD with the presence of $Fe2O_3$ in a few samples. This phase is further reduced, and the cobalt starts to appear in the sample. Different vibrational modes are studied using Raman spectroscopy. The main aim of this study is to measure the response of the $\mathrm{Co}$ doping in $\mathrm{Mn}$ and $\mathrm{Zn}$ ferrite in microwave frequency region from $1GHz$ to $18GHz$. For this purpose, the prepared ferrites were characterized with a Vector network analyzer (VNA) using a coaxial air cell to measure the permittivity, permeability, and dielectric loss tangent. The synergetic response shows superior electromagnetic reflection over broad frequency bandwidth with cobalt. These dielectric properties are useful for radar and defense applications.