Impact of Green Synthesis on Crystallographic Structure, Optical and Magnetic Properties of Nanocrystalline CoFe₂O₄

CoFe₂O₄ nanocrystals were synthesized through chemical co-precipitation using citric acid as the capping agent. Subsequently, a green alternative was accomplished in the synthesis process by replacing the commercially purchased citric acid with naturally available lemon juice. The prepared samples were thoroughly characterized using various techniques, and the results were analyzed and the parametric variations in the two samples were compared. Using Rietveld profile refinement of the XRD patterns, the crystallographic parameters associated with both samples were explored and the cation distributions in the tetrahedral and octahedral sites were estimated. Williamson–Hall analysis of x-ray diffraction data provided the effective crystallite size and the microstrain associated with the nanocrystalline samples. The optical direct band gap and the room-temperature magnetic parameters were estimated from UV–visible spectra analysis and vibrating sample magnetometry, respectively. The coercivity, remanent magnetization, and saturation magnetization of both samples were obtained from magnetic hysteresis, and the estimated values for magnetic anisotropy energy revealed that the samples exhibited room-temperature ferrimagnetic behavior.