Effect of Annealing on Structural Properties of Fe3O4 Ferrite Nanoparticles
Nano-crystalline Fe3O4 particles has been synthesized by chemical co-precipitation method. The synthesized samples were annealed at different temperature 300 °C, 500 °C, 700 °C. The effect of annealing temperature on structural properties of synthesized sample has been studied by various analytical techniques like X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope and Fourier transform infrared spectroscopy (FTIR). The X-ray diffraction patterns confirm the synthesis of single crystalline phase of Fe3O4 nanoparticles. The crystallite size of synthesized iron oxide nanoparticles is about 7 nm. The crystallinity of iron oxide nanoparticles is enhanced by annealing treatment which is also confirmed by corresponding SEM and TEM micrographs. A phase transition from magnetite (Fe3O4) to hematite (α-F2O3) is observed when the samples are annealed above 500 °C. The fundamental groups of the iron oxide and annealed samples have been identified from FTIR spectrum. The particle size calculated from TEM images for the Fe3O4 sample varies in the range 5–20 nm and it has been observed that the particle size increases on annealing.