Influence of orange residue content on Sol-gel synthesis of cobalt ferrite Nanoparticles: Morphological and magnetic properties

Cobalt ferrite was successfully produced from nitrates using, as a precursor, 20, 40 or 60 g.L-1 of orange residue in water, followed by calcination at 973, 1073, or 1173 K for 6 h. Fourier transform infrared spectroscopy indicates that the increase in carbonyl-related peak content in the precursor bath due to a higher concentration of orange particulate favors the reaction of nanocrystals' formation. Rietveld's analysis of x-ray diffraction data indicates that the percentage of cobalt ferrite tends to increase with the concentration of orange residue, whereas grain size increases with calcination temperature. The concentration of cobalt ferrite is 99% for samples produced with 60 g.L-1 of orange particulate, a novel achievement for green synthesis using an industrial residue as a precursor. Magnetic anisotropy, obtained from ferromagnetic resonance measurements, scales with the crystalline grains' size, being dependent on calcination temperature, regardless of orange particulate precursor concentration.