Structural and magnetic properties of CoFe2O4 nanoferrite simultaneously and symmetrically substituted by Mg, Sr and Mn

MgxSrxMnxCo1−3xFe2O4 nanoferrite series (with x = 0, 0.1, 0.2, 0.3, 1/3) were synthesized by glycol-thermal technique. The average crystallite size, lattice parameter, X-ray density and microstrain were calculated from X-ray diffraction data and the average crystallite size confirmed by high-resolution transmission electron microscopy in the range of 7.5-9 nm. Energy dispersive X-ray spectroscopy was used to identify qualitatively the constituent elements in the synthesized compounds. High resolution scanning microscopy scans show almost spherical shaped nanoparticles. Mössbauer spectroscopy measurements reveal magnetic order of the compounds at about 300 K and the distribution of Fe3+ ions at tetrahedral and octahedral sites. The sample at x = 1/3 has the lowest coercive fields, magnetizations and hyperfine fields. At low temperature magnetic measurements of the series shows spin freezing effects for samples x = 0, 0.1, 0.2 and significant changes in magnetizations and coercive field as a function of composition and temperature.