Influence of li1+ (alkali metal) ion on structural, optical and magnetic properties of nickel ferrite nanomaterials for multifunctional applications

Abstract Lithium substituted nickel ferrite nanoparticles, LixNi1-xFe2O4 (x = 0 and 0.5) synthesized using citrate precursor method at a low annealing temperature of 550 °C. The effect of Lithium on structural, morphology, magnetic and optical properties of nanoparticles has been studied. X-ray diffraction measurements show the formation of cubic spinal crystal. The crystallite size were evaluated by Williamson-Hall plot and found to be 26 nm and 24 nm respectively. Monotonically increase in lattice constant and lattice strain was observed with the substitution of Lithium atom. FTIR measurements show, two characteristics absorption peaks of cubic spinel ferrites at range around 580 cm−1 and 470 cm−1 wave number. Morphology of the sample was studied using Scanning Electron Microscopy and found change in agglomeration due to change in antiparticle interaction. The Indirect band gap were found 2.20 eV for Nickel ferrite and 2.28 eV for substituted Li ferrite. Photoluminescence spectra show that strong luminescence in visible range. Magnetic parameter such as remanence, coercivity, and saturation magnetization increases with increase in lithium ion concentration (Mr- 7.57 emu/g- 14.478 emu/g, Hc −178Oe-192Oe and (36.5 emu/g to 41.5 emu/g). Force constant and bond length were found to dependent on Lithium ion. Thus prepared Lithium substituted ferrite nanomaterials possess pure phase crystal, uniform growth in magnetism with luminescence in visible ranges, which can be useful for multifunctional applications in various areas of science and technology.