Evaluations of the Thermal, Rietveld Structural, Microstructural and Magnetic Properties of Cu0.5Co0.5BixFe2−xO4 Spinel Nanoferrites

Bi-doped Cu-Co spinel nanoferrites with composition Cu 0.5 Co 0.5 Bi x Fe 2-x O 4 (where x varies as 0, 0.02, 0.04, 0.06, 0.08, and 0.10) were synthesized using sol–gel auto combustion. The nanoferrites were characterized by thermogravimetric analysis (TGA), x-ray diffraction (XRD), field emission scanning electron microscopy, vibrating sample magnetometry and Fourier transform infrared spectroscopy to evaluate the thermal, structural, microstructural and magnetic properties of Bi-doped Cu-Co nanoferrites, respectively. TGA curves depicted the weight loss for x = 0.06, 0.08 and 0.10 at higher temperature. Single-phase structure with crystallite size ranging from 43 nm to 63 nm was observed from XRD. The rietveld refinement of the Bi-doped Cu-Co nanoferrites was also done to evaluate the detailed structural properties. Rwp, Rb, Rwnp, Rexp and GOF (Sig) were evaluated for Bi-doped Cu-Co nanoferrites samples. Phase and functional characteristic bands of the Bi-doped Cu-Co nanoferrites were analyzed using FTIR. Force constants were found to be increased with Bi content. The systematic effects of Bi on the morphology of Cu-Co ferrite were examined by SEM analysis. The average grain size was 156 nm to 326 nm, respectively. Magnetic properties of the Bi doped Cu-Co nanoferrites were calculated from the magnetic loops. Magnetic saturation of Cu-Co nanoferrites was 29.2 emu/g and decreased with increasing Bi concentrations in Cu-Co ferrites. In addition, the remanence magnetization was also decreased from 19.4 emu/g to 4.09 emu/g, respectively. The initial permeability for Cu-Co nanoferrites was 6.98 whereas it was increased up to 17.81 emu/g with Bi doping. The present study revealed that Bi doped Cu-Co nanoferrites is suitable material for high-frequency switching and microwave absorption devices applications.