Correlation of synthesis parameters to the structural and magnetic properties of spinel cobalt ferrites (CoFe2O4) – an experimental and statistical study

• Published in: Journal of magnetism and magnetic materials Vol. 550; p. 169128
• Main Authors: Eduardo Caldeira, Luis, Stockey Erhardt, Camila, Ravanello Mariosi, Fabricio, Venturini, Janio, Young Sun Zampiva, Rubia, Rubem Klegues Montedo, Oscar, Arcaro, Sabrina, Pérez Bergmann, Carlos, Roca Bragança, Saulo
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-05-2022; Elsevier BV
• Subjects: Annealing; Cobalt ferrites; Coercivity; CoFe2O4; Crystallites; Ferrites; Initial conditions; Magnetic properties; Nanoparticles; Optical properties; Parameters; Raman spectroscopy; Sol-gel; Sol-gel processes; Spinel; Statistical analysis; Statistics; Synthesis; Temperature; Ferrites; CoFe2O4; Temperature; Statistics; Sol-gel
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2022.169128

•Longer treatments at higher temperatures produce less inverted CoFe2O4 particles.•Lower temperatures and shorter firing times resulted in higher coercivities.•Firing time has a lower influence on the results than treatment temperature.
Several studies have shown the exceptional responses of spinel cobalt ferrites as advanced ceramics. Nevertheless, there is still a gap in the literature regarding the effect of synthesis parameters on the properties of the spinel products. This work aims to correlate temperature and annealing time with the structural, optical, and magnetic properties of CoFe2O4. Precursors were prepared by sol–gel and thermally treated at 550, 650, and 750 °C for 2, 4, and 6 h. The microstructure was characterized by XRD, BET, SEM, and Raman spectroscopy. Treatment longer than 6 h at temperatures higher than 650 °C produced less inverted nanoparticles with larger crystallites. Although the initial annealing conditions did not influence the ferrites bandgap, VSM results showed an opposite response. The maximum in coercivity (1654.25 Oe) was obtained in the sample annealed in the shortest time (2 h) and at the lowest temperature (550 °C). Statistical analyses prove that despite not affecting the results in the same manner, both initial conditions affected the CoFe2O4 properties. Our results open up the possibility of improving the CoFe2O4 manufacturing process for commercial exploration.