Hydrothermal synthesis of CoyZnyMn1-2yFe2O4 nanoferrites: Magneto optical investigation

Manganese ferrites nanoparticles (NPs) substituted with both Co2+ and Zn2+ simultaneously (CoyZnyMn1-2yFe2O4 NPs for y = 0.0 to 0.5), have been produced by hydrothermal approach. The substitution with both Co2+ and Zn2+ ions on the structure, spectroscopic and magneto-optical properties of nanocrystalline MnFe2O4 spinel ferrites have been analyzed in detail. The formation of spinel phase and structural changes induced by Co2+ and Zn2+ ions substitutions were confirmed by X-ray diffraction studies. Rietveld refinement revealed the cubic spinel phase for all products (minor amount of Fe2O3). Lattice constant and crystallite size were found to decrease from 8.478 to 8.370 angstrom and from 14.68 to 8.22 nm, respectively with increasing substitution of Co2+ and Zn2+ ions. HR-SEM and FIR-TEM micrographs revealed the high homogeneity cubic structure of samples. The hyperfine magnetic field values for all products after Mn2+, Zn2+ and Co2+ ions substitution were determined by Mossbauer analysis. The estimated optical E-g (Energy band gap) values are in the range of 1.41-1.54 eV for the samples. The smaller E-g values are mainly attributed to greater particle size and decreasing quantum confinement effect.