SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NICKEL FERRITE NANOPARTICLES: EFFECT OF CALCINATION TEMPERATURE ON PARTICLE SIZE, STRAIN, AND DEFECT DENSITY

Nickel ferrite nanoparticles (NPs) (NiFe2O4) were synthesized using the co-precipitation method. The resulting nanomagnets (A1, A2 and A3) were characterized using various techniques. The size of the nanomagnetic particles was estimated to be 7nm for A1, 10 nm for A2 and 16 nm for A3 based on the transmission electron microscopy (TEM) image and X-ray diffraction analysis (XRD) pattern (using the Debye–Scherrer equation). The Full Width at Half Maximum intensity (FWHM) decreases with the increase in calcination temperatures, i.e. FWHM of A1 is greater than that of A2 and FWHM of A2 is greater than that of A3. Diffraction peaks broaden either because of inhomogeneous micro strain induced by dislocation-like defects (strain broadening) or because of shrinkage of coherent scattering volume (size broadening). The observed broadening of peaks is likely the combined result of both effects. Strain broadening and size broadening can be separated by WH plotting. Scanning electron microscopy (SEM) images of uncoated NiFe2O4 NPs is also done. NiFe2O4 NPs can be proposed as a viable material for biomedical applications.