The effect of annealing on microstructure and cation distribution of NiFe2O4

Abstract

Nickel ferrite nanopowder was synthesized using a co-precipitation method, and further annealed at three different temperatures of 500°C, 750°C and 900°C. The effect of annealing process was explored on particle size, cation distribution and magnetic properties of NiFe2O4. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and with the use of a vibrating sample magnetometer. The X-ray diffraction patterns at different annealing temperatures demonstrated the existence of only spinel phase of NiFe2O4. The results of Rietveld analysis showed that the sample annealed at 750°C possesses inverse spinel structure, while the others have partially inverted spinel structure. The SEM analysis indicated a change of particle size and morphology at higher annealing temperature. The change in Raman modes was observed with the change of particle size and cation distribution. The highest value of the saturation magnetization (38 emu g−1) was obtained at annealing temperatures of 900°C.