Crystal structure of superparamagnetic Mg0.2Ca0.8Fe2O4 nanoparticles synthesized by sol–gel method

• Published in: Journal of magnetism and magnetic materials Vol. 374; pp. 474 - 478
• Main Authors: Escamilla-Pérez, A.M., Cortés-Hernández, D.A., Almanza-Robles, J.M., Mantovani, D., Chevallier, P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-01-2015
• Subjects: Magnetic hyperthermia; Magnetic nanoparticle; Magnetic property; Sol–gel method; Superparamagnetism; Magnetic nanoparticle; Magnetic property; Magnetic hyperthermia; Superparamagnetism; Sol–gel method
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2014.08.086

Powders of magnetic iron oxide nanoparticles (Mg0.2Ca0.8Fe2O4) were prepared by a sol–gel method using ethylene glycol and nitrates of Fe, Ca and Mg as starting materials. Those powders were heat treated at different temperatures (573, 673, 773 and 873K). In order to evaluate the effect of the heat treatment temperature on the nanoferrites properties, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques were used. It was found that the reaction products exhibit nanometric sizes and superparamagnetic behavior. It is also demonstrated that, as the heat treatment temperature increases, the particle size and the saturation magnetization of the nanoferrites are increased.
•Mg0.2Ca0.8Fe2O4 superparamagnetic nanoparticles were successfully synthesized.•Particle average sizes of Ca–Mg ferrites were within the range of 8–25nm.•The nanoferrite treated at 873K showed a stoichiometry close to Mg0.2Ca0.8Fe2O4.•The heat treatment temperature has a strong effect on the crystal structure.•These nanoparticles are potential materials for magnetic hyperthermia.