Spectral studies of nano Ni ferrite doped with Cr ions

Nano-crystalline NiCrxFe2-xO4 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) system have been synthesized by the flash auto-combustion method annealed at 400°C for 2h. The X-ray diffraction (XRD) technique was employed to confirm the single phase formation of nickel ferrite. The transmission electron microscopy (TEM) was used to characterize the nanostructure of ferrite. All samples were crystallized in a spinel cubic structure. The (IR) spectra was recorded in the range from 200-4000cm^-1. The absorption bands at 601cm^-1 (ν1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\nu_{1}$\end{document} and 410 cm-1 (ν2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\nu_{2}$\end{document}) were assigned to tetrahedral (A site) and octahedral (B site) groups complex. The morphological observation which was determined by scanning electron microscopy (SEM) shows agglomerated grains with different shapes and sizes. The values of lattice constant, X-ray density, bulk density, and porosity were calculated. The decrease in the lattice constant was endorsed to the difference in ionic radius of both Fe3+ (0.67 Å) and Cr3+ (0.64 Å). The particle size was found in the range of 18-25nm by X-ray and TEM analysis. The porosity has an inverse character with the bulk density.