Dixit, GaganPant, Chitresh Mohan2021-12-172021-12-172021-10https://krishikosh.egranth.ac.in/handle/1/5810179393Ferrites are magnetic materials having spinel structure. They are important because of their various properties which make them applicable in many fields such asmedical diagnosis, electronic industry, automobile, military applications, etc. Properties of ferrites depend upon the synthesis method, temperature, cation distribution, doping with different metal ions etc. Swift Heavy Ion Irradiation is very unique tool to modify the properties of material. Present work is an attempt to study the effect of 100 MeV oxygen ion induced modification on structural and optical properties of 4% Ce and Gd doped Nickel ferrite thin films. The samples were synthesized by chemical route using citric acid and thin films have been prepared by Pulsed Laser Deposition technique. Structural and optical properties were studied using XRD and UV-Vis Spectroscopy. XRD confirmed the cubic spinel structure of pristine and irradiated samples. After doping with rare earth ions crystallite size was decreased and lattice parameter was increased. After irradiation at lower fluence , pure and Ce doped nickel ferrite thin films show some impurity which disappears at higher fluence while Gd doped films remain in pure phase. The reflectance spectra for all the samples were recorded by UV-Vis spectroscopy. The direct band gap was found to increases with doping of rare earth ion. For nickel ferrite thin films, band gap was found to increase with fluence of irradiation while for rare earth doped nickel ferrite thin films, there was not significant change in band gap. Both structural and optical studies indicate that Gd doping has enhanced the resistivity of nickel ferrite thin films towards irradiation induced changes in comparison to Ce doping. Swift heavy ion irradiation can be considered as an effective tool for modifying optical properties in comparison to doping with rare earth ions.EnglishThesis