Structure, Magnetic Properties, and Hyperthermia of CoxFe3–xO4 Nanoparticles Prepared by the High-Energy Ball Milling Method

Abstract

Co_xFe_3–xO₄ (x = 0.0, 0.5, and 1.0) single-phase microcrystalline samples are obtained by mechanochemical synthesis. They are studied comprehensively by X-ray structural analysis, vibration magnetometry, Mössbauer spectroscopy, and neutron diffraction. The crystal-chemical formulas are established, and the magnetic properties of the compounds are characterized. The Co_xFe_3–xO₄ (x = 0.0, 0.5, and 1.0) nanoparticles are obtained by wet high-energy milling of the single-phase microcrystalline samples. It is shown that the average size of the synthesized nanoparticles is from 11 to 13 nm. There is a decrease in the coercive force for all Co_xFe_3–xO₄ nanocrystalline samples compared to their microcrystalline analogs, which is due to there being a large proportion of nanoparticles in the superparamagnetic state. The specific power loss values calculated from hyperthermia effect measurements appear to be maximum (3.5 W g^–1) for the Fe₃O₄ sample (x = 0.0), which is explained primarily by the ratio of its coercive force and the amplitude of the applied alternating field strength.