THE STUDY OF STRUCTURAL AND MAGNETIC PROPERTIES OF COBALT DOPED NICKEL FERRITE (CoxNi1- xFe2O4) NANOPARTICLE

Abstract

ADVISOR: SENBETO KENA ETANA (PHD) ABSTRACT Cobalt doped Nickel ferrites, (Ni1-xCoxFe2O4) nano particles where x=0, 0.05 and 0.1 were success fully synthesized by sol-gel auto-combustion method. In this synthesis Nickel nitrate hexahydrate (Ni(NO3)2.6H2O),Cobalt nitrate hexahydrate(Co(NO3)2.6H2O),Ferric nitrate nonahydrate (Fe(NO3)3.9H2O) and Citric acid (C6H8O7) were weighed and mixed in a beaker of 150ml containing amount of doubly de ionized water under stirring. The obtained particles sintered at 550 for 2h to remove impurity and organic substances. The powder was then grinded again for 1hr and held in alumina crucible again and was loaded in temperature programmed electric furnace at 700oC for 3 hours for final sintering for more densification. With the help of the XRD machine, the phase formation and structural analysis of the samples have been carried out. From the XRD result, the crystallite sizes were found to be 11.90nm, 35.60nm and 46.60nm, When x=0.00, 0.05 and 0.10, respectively. The crystal lattice parameters were 0.833nm to 0.830nm, for x increased from 0.00 to 0.10. The surface morphology has been studied using Transmission Electron Microscopy. The micro-structural evolution of cobalt nickel ferrite (Ni1- xCoxFe2O4) powders at 700°C temperature under various Co2+ -doping levels i.e. at x = 0.00,0.05, and 0.10 were studied by SEM digital images. The estimated amounts of (in atomic percentage) O, Fe, Ni and Co in the pure and CNF samples are confirmed from EDS spectra analysis which are tabulated in Figure 4.3. The concentration of Fe has remained nearly same in all powders and the concentration of Co is increased as the Co2+ -doping level is increased. The CNF samples obtained at x = 0.05 and 0.10 exhibit different stoichiometry. The magnetic properties of the synthesized samples were carried out using Vibrating Sample. From VSM result the saturation magnetization, remnant magnetization and coercive Filed were found to be from 14.049emu/g to 23.559emu/g, from 2.118emu/g to 7.367emu/g and from 86.429G to 404.264G when x-values increased from 0.00 to 0.10, respectively. The prepared sample has technological applications in microwave devices, recording media, gas sensors, high density information storage, and etc. In generally the crystallite sizes, lattice parameter, surface morphology, elemental composition and magnetic parameter are vary sample to sample and have been mention in this paper. Keywords: Synthesis, structural properties, magnetic properties, nano particles