Sol-gel auto-combustion synthesis of Co0.5Cu0.5Cr0.5GdxFe1.5-xO4 spinel ferrites and their magneto-dielectric properties

In this work, Gadolinium (Gd3+) substituted Co-Cu-Cr (CCC) SFs with the chemical formula Co0.5Cu0.5Cr0.5GdxFe1.5-xO4 (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized via the self-combustion process. The single-phase matrix of the Gd3+ substituted CCC SFs was verified using X-ray diffraction (XRD). The crystallite size (D) of Gd3+ doped CCC SFs was reduced from 51.20 nm to 36.27 nm with increasing Gd3+ doping. The addition of Gd3+ in the CCC SFs lattice enhanced specific surface area (S) from 22.11 cm(2)/g to 28.57 cm(2)/g. The energy bandgap (E-g) was increased from 4.83 eV to 5.40 eV and revealed an inverse relation with crystallite size. The tangent loss (tan delta), dielectric loss (epsilon"), dielectric constant (epsilon'), and ac conductivity (sigma(ac)) of Gd3+ doped CCC SFs exhibit frequency-dependent behaviour. The behaviour of these dielectric properties has been analyzed using both Koop's theory and the Maxwell-Wagner model. Moreover, it was found that the epsilon' was enhanced, while sigma(ac) and tan S was reduced with the doping of Gd3+ in CCC SFs. The saturation magnetization and microwave operating frequency were increased with the doping of Gd3+ in CCC SFs. Because of their diverse dielectric and magnetic properties, the Gd3+ doped CCC SFs have considerable potential for different applications, including microwave absorption materials, switching high-frequency devices, and microwave frequencyoperating devices.