Synthesis and optical characterization of nanocrystalline NiFe2O4 structures

Nickel ferrite (NiFe2O4) nanostructures have been synthesized by sol-gel method using glycolic acid as a chelating agent. Glycolic acid acts as a fuel, which decomposes the metal complexes at low temperature and yields impurity-free NiFe2O4 nanocrystalline structures. NiFe2O4 nanostructures, derived from thermal decomposition of the gel precursor, were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron micrographs (FESEM) and UV-vis absorption spectroscopy. The XRD results show that the nanocrystal contains single phase spinel structure with (Fd3m space group). The average particle size of nanostructured NiFe2O4 crystallites was calculated and found to be 27 +/- 2 nm, which is in good agreement with the particle size calculated through FESEM micrographs. The energy band gap of the synthesized NiFe2O4 nanocrystalline structure was calculated to be similar to 5 eV. The optical studies show a direct allowed transition in NiFe2O4 nanostructures. (C) 2009 Elsevier B.V. All rights reserved.