Effect of annealing temperature on structural and magnetic properties of manganese substituted NiFe2O4 nanoparticles

The structural and magnetic properties of manganese substituted nickel ferrite nanoparticles were synthesized by auto-combustion and evaporation methods. The effects of annealing treatment on structural and magnetic behavior of the samples have been studied for 600 °C and 900 °C. The ferrite powders were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The X-ray diffraction patterns indicated that the annealed samples resulted in the formation of Mn-Ni ferrite and the presence of α-Fe2O3 as a secondary phase. The average crystallite sizes of the annealed samples are in the range from ~25 to 65 nm for auto combustion method and ~45 to 98 nm for evaporation method. The morphology and particle size of the annealed samples are examined by SEM and TEM. The annealing effect on the magnetic properties of Mn-Ni ferrites were analyzed by using a Vibrating Sample Magnetometer (VSM). The impact of particle size, the saturation magnetization of Mn-Ni ferrite nanoparticles increase with increasing annealing temperature.