Improvement in magnetic behaviour of cobalt doped magnesium zinc nano-ferrites via co-precipitation route

Abstract Nanoparticles of spinel ferrites have attracted huge interest in various technological applications due to their distinct magnetic behaviour. These magnetic nanoparticles acquire surface and finite size effects. We report an improvement of magnetic characteristics in Co 2 + substituted Mg Zn nano-ferrites synthesized by co-precipitation route. Physical properties have been investigated for Mg 0.5 Zn 0.5−x Co x Fe 2 O 4 ( x = 0, 0.125, 0.250, 0.375, 0.500) nano ferrites using XRD, FTIR, FESEM, EDS, VSM, photoluminescence and UV spectroscopy. Single phase cubical spinel structure has been observed. A phase transition from superparamagnetic to ferrimagnetic behaviour for x > 0.125 has been observed. Saturation magnetization has been found to be enhanced. Frequency dependent dielectric behaviour shows normal dispersion. Absorption spectra show a shift in position of maximum absorption towards longer wavelength with increasing Co 2+ content. Photoluminescence spectroscopy has also confirmed the red shift in band edge emission with increasing Co 2+ content. Some theoretical parameters, using proposed cation distribution, like theoretical lattice parameter, oxygen positional parameter, bond length etc., have also been calculated and found to support our experimental results.