Particle size, morphology, and properties of transition metal ferrospinels of the MFe2O4 (M = Co, Ni, Zn) type, produced by glycine-nitrate combustion

Resumo

Ferrites-spinels of the MFe₂O₄ type (M = Co, Ni, Zn), produced by glycine-nitrate combustion were studied. A physicochemical study of ferrite samples was performed by X-ray fluorescence analysis, scanning electron microscopy, X-ray phase analysis, and X-ray spectroscopy. The average size of the coherent scanning region was found to be (nm): 28 ± 2 for CoFe₂O₄, 32 ± 2 for NiFe₂O₄, and 26 ± 2 for ZnFe₂O₄. Magnetic characteristics were determined by the NMR method. The specific residual magnetization, specific saturation magnetization, and coercive force were, respectively, 14.1 A m² kg⁻¹, 20.1 A m² kg⁻¹, 31800 A m⁻¹ for CoFe₂O₄; 4.4 A m² kg⁻¹, 23.1 A m² kg⁻¹, 6550 A m⁻¹ for NiFe₂O₄; and 5.1 A m² kg⁻¹, 18.3 A m² kg⁻¹, 3200 A m⁻¹ for ZnFe₂O₄. Their magnetic properties show that the resulting ferrospinel powders can be used in the following fields of technology: CoFe₂O₄ in those areas where heat transfer is necessary (hyperthermia) and in development of data storage media; NiFe₂O₄ and ZnFe₂O₄ in those areas where low heat exchange is necessary, ZnFe₂O₄ for fast remagnetization and NiFe₂O₄ as a core or shell for transportation of other substances. The ferrospinel samples compare well in magnetic properties with their foreign commercial analogs, which makes these compounds commercially viable.