Improved magneto-dielectric properties in Co substituted Cr ferrites for miniaturized antenna applications

Abstract

The composition Cr(Fe1-xCox)2O4 with x =0.0, 0.1, 0.5, and 0.9 has been synthesized using the solid-state re action method followed by the double sintering technique of pre-sintering at 800 ◦C and sintering at 1332 ◦C. The structure and cationic distribution in the studied samples obtained by the Rietveld refinement of X-ray diffraction (XRD) patterns confirm a mixed spinel cubic structure of Fd3m space group, with a reduction in impurity phase (α-Fe2O3) as Co2+substitution increases. In addition, the scanning electron microscopy (SEM) of these samples indicates a decrease in grain size and porosities with higher Co content. The magnetic hysteresis measurement by a vibrating sample magnetometer (VSM) reveals that Co2+substitution at Fe3+enhances the magnetic properties, with maximum saturation magnetization (Ms)of ∼4.03×10 2 μB/F.U and coercivity (Hc) of ~102.1Oe observed for x=0.5. In addition, the frequency-dependent permeability (μ) improves with Co doping in Cr ferrite, and dielectric studies exhibit reduced loss tangent (tanδ)and enhanced dielectric quality factor (Qε). Finally, the matching impedance becomes stable across a broad frequency range (3kHz to 7MHz) with Z/η0≈0.75, resulting in the Co-substituted Cr ferrites as promising materials for miniaturized antenna applications including superior magneto-dielectric performance and eco-friendly composition.