XRD and SEM characteristics of Co-Ni ferrite nanoparticles Synthesized using sol-gel method

Abstract

Nickel-doped Cobalt ferrites nanoparticles (NPs) with chemical formula Co1-xNixFe2O4 (were, x= 0, 0.5, and 1) were
synthesized at low temperature (200oC) using sol-gel autocombustion technique. Citric acid as a chelating agent used
with the mixture of nickel nitrate and ferric nitrate solutions in a ratio of (3:1) to balance the oxidizing agent to
reducer ratio. The obtained ferrite NPs were calcined at deferent temperatures (200, 400, 600, and 800°C) for 4h in
the air to remove the water content, unwanted impurities and to obtain a single-phase spinel structure with better
crystallinity. Structural characteristics of the calcined ferrite NPs were confirm by the analysis of the X-ray
diffraction (XRD) technique. XRD analysis shows the single-phase cubic spinel nanocrystalline structure. The
crystallite size calculated from FWHM of the strongest peak (311) is in the range of (27-44 nm) for Co1-xNixFe2O4
ferrite NPs. While, the Co0.5Ni0.5Fe2O4 NPs have crystallite size larger than that of NiFe2O4, but smaller than
CoFe2O4 NPs. The lattice constant, X-ray density, and other structural parameters calculated from XRD data are in
good agreement with the literature values. SEM images show NPs with spherical shape and homogenous
morphology with particle size in the range of (25-47 nm), reflecting the highly crystalline nature of these
nanoparticles. The average grain size of the samples obtained from SEM images is larger than the crystallite size
calculated using XRD measurement, furthermore the distribution of the grains for Cobalt ferrite better than that of
Nickel and Co-Ni ferrites. The particle size and grain size of the Co1-xNixFe2O4 ferrite NPs that calculated using
XRD and SEM techniques are compatible with each other in the same range