Synthesis and characterization of V and Gd substituted Cobalt Ferrite nanoparticles

Abstract

In this work Vanadium and Gadolinium doped nanocrystalline cobalt ferrite CoMxFe2-xO4, where M represents V or Gd and x= 0%, 2%, 5% and 10% were synthesized by coprecipitation method. The undoped sample was annealed at 500 and 900⁰C. It was found that the crystallite size increased with increasing annealing temperature. The doped samples were therefore annealed at 900⁰C. The formation of a cubic spinel phase was confirmed by XRD. The crystallite sizes of the V doped samples were calculated to be between 39 and 44nm, while the crystallite sizes of the Gd doped samples ranged from 35 to 47nm. According to XRD, the crystallite size improved with sintering temperature. With V doping, particle size showed a decreasing trend, followed by an increasing trend. This is because V replaced iron in the octahedral location, reducing crystallite size, but as doping concentration increased more than 5%, Fe began to move towards the tetrahedral site, increasing crystallite size. The crystallite size was found to lower because of Gd substitution. SEM imaging was used to study the morphology of ferrites. In SEM images, nanocrystalline particles can be seen arranged into layers with a porous structure. The presence of Co, Fe, V and Gd elements in the samples was shown by EDX analysis. According to FTIR measurements, the vibrational peaks associated with octahedral and tetrahedral sites vary with doping. PSD analysis showed the formation of particle agglomeration. BET adsorption isotherm was used to calculate the specific area of samples. Using VSM, magnetic properties such as coercivity, retentivity, and saturation magnetization were determined. According to the VSM study, all samples were ferromagnetic. Doping increased remanence magnetization.