Morphological and structural properties of bismuth-nickel ferrite synthesized by a combined sol-gel method

Abstract

In this paper, Bi _x Ni_1-x Fe₂O₄, (x = 0, 0.3, and 0.5), nanoparticles were synthesized by a sol–gel method, and the synthesized samples were calcination at 350 and 650^o C for 3 h. The influence of Bi doping on morphological and structural properties was studied. The field emission scanning electron microscopy (FESEM) analysis showed all of the specimens contain a compact order of homogenous nanoparticles with a spherical form and polyhedral particles with an average size ranging from 36.305 nm to 27.554 nm at 350 and 650^o C respectively. By studying the energy dispersive spectrometer analysis patterns, the existence of constituent elements, Ni, Bi, Fe, and O, was verified with a proportion very close to the stoichiometry of the chemical formula. The formation of a ferrite phase was confirmed by X-ray diffraction. An increase in the average crystallite and grain size has been observed with an increase in Bi doping. The Fourier Transform Infrared(FT-IR) studies were made in the frequency range 400-4000 cm^-1 and observed two strong absorption peaks. The frequency band is found at 555 cm^-1 whereas the lower frequency band is at 1338.5 cm^-1. It is noticed that the two prominent absorption bands were slightly shifted towards the higher frequency side with the increase of Bi3+ ion concentration.