Insights into the microstructural, optical and magnetic characteristics of cobalt and dysprosium co-doped BaFe₁₂O₁₉ M-type hexagonal ferrites

This current work aims to analyze the fabrication of Cobalt and Dysprosium co-doped BaFe₁₂O₁₉ of chemical composition, Ba_1-xCo_xDy_yFe_12-yO₁₉ (x = y = 0.2–0.6) via, the sol-gel auto-combustion (SGAC) technique, with its main objective to improve their structural, surface, microstructural, optical, and magnetic traits. X-ray diffraction reveals the hexagonal structure of prepared co-doped barium hexaferrites with an additional phase of α-Fe₂O₃ and it is also validated by the Rietveld refinement. The computed crystallite size (D) falls between 22.40 and 41.02 nm. The grain size distribution at the surface of doped barium hexaferrites is reported by the field emission scanning electron microscopy (FESEM) study within in the range of 102.05 to 189.43 nm. The FESEM results confirms a hexagonal morphology for all the samples. The fundamental metal-oxygen (M-O) stretching vibrations at the tetrahedral and octahedral positions are detected via Fourier-transform infrared spectroscopy (FTIR). This approves the existence of distinctive functional groups within the developed hexaferrites. Seven Raman active band positions are found in the Raman spectra of Ba_1-xCo_xDy_yFe_12-yO₁₉ hexaferrites. The computed specific surface area is found to be 3.478 and 3.352 m²/g for the CDH1 and CDH3 hexaferrites. The magnetic results show that with the doping, the coercivity and saturation magnetization decreases. Therefore, due to the excellent Brunauer-Emmett-Teller (BET) and Vibrating sample magnetometry (VSM) results, the Ba_1-xCo_xDy_yFe_12-yO₁₉ hexaferrites are highly beneficial in the sensors and magnetic recording applications.