Srivastava, R.C.Ritu2022-02-042022-02-042021-10https://krishikosh.egranth.ac.in/handle/1/5810181713The cobalt ferrite nanoparticles are useful in many fields because of their admirable mechanical and chemical stability, highly magnetocrystalline anisotropy, moderate saturation magnetization, low eddy current losses and high coercivity. The present investigation was aimed to study the structural and optical properties of cobalt ferrite nanoparticles before and after the gamma irradiation with total dose of 500Gy and 1kGy. The cobalt ferrite nanoparticles were synthesized via sol-gel auto combustion method. The structural parameters were obtained through XRD pattern by using the OriginPro software and also by Rietveld refinement technique using FullProf software. The lattice parameter obtained were in the range from 8.403 Å to 8.360 Å. It decreased with increasing the total dose. The interplanar spacing decreased from 2.53 Å to 2.52 Å and specific surface area also decreased from 27.9m2/g to 21.3m2/g with the gamma irradiation. The X-ray density increased from 5.254g/cm3 to 5.336g/cm3 after irradiation. The crystallite size changed from 41nm to 53nm when calculated by Debye-Scherrer’s formula and from 47.63nm to 59.74nm when evaluated by W-H plot, with increasing the gamma dose. The tensile strain in the crystal changed to the compressive strain after the irradiation. The bond length, occupancy and the cation distribution were also changed by gamma irradiation. The optical analysis of cobalt ferrite was carried out by using the UV-Vis diffuse reflectance spectroscopy. The optical band gap was decreased with the gamma dose from 1.370 to 1.343eV. The value of energy band gap showed that the all samples were semiconductor in nature.EnglishThesis