Structural Elucidation and Magnetic Behavior Evaluation of Nd-doped Nickel-Cobalt Spinel Ferrites

Abstract

Nano ferrites crystals of Ni_0.4Co_0.6Nd_xFe_2-xO₄ for 0.00 ? x ? 0.08 with step size of 0.02 were synthesized by sol gel technique with annealing at 950 ^oC for 6 hours. Spinel phase along with a secondary phase for Nd concentration x ? 0.04 due to formation of NdFeO₃ was observed in XRD patterns. Lattice constant and grain size were found in decreasing trend with increasing concentration of Nd as compared to that of undoped nickel cobalt ferrites. X-ray density and porosity both were increased with increasing concentration of neodymium. Two characteristics frequency bands were observed in the range of 400cm^-1 to 550 cm^-1 which showed successful formation of spinel structure. It is also the evidence of metal-oxygen bonding at octahedral and tetrahedral sites in spinel ferrites. Also, bands for carbon-hydrogen, carboxyl group, carbon-oxygen stretching and iron-cobalt alloys were observed in the FTIR spectra. By using these values of characteristics frequencies, octahedral and tetrahedral radii were calculated and found in decreasing trend with increasing concentration. Force constants are increasing with increase in neodymium concentration. Saturation magnetization, coercivity and remanence values were calculated from the M-H loops. Saturation magnetization showed the decreasing behavior with increase in neodymium concentration. Coercivity showed increasing values as compared to the base sample and also showing reciprocal relation with saturation magnetization. Magnetic moment is decreasing with increase in neodymium concentration.