Tunable Optical Bandgap of Gadolinium Substituted Nickel-Zinc Ferrite Nanoparticles-Effect of Calcination Temperature on Its Optical Parameters

The gadolinium substituted nickel-zinc ferrite nanoparticles of the composition, Ni0.5Zn0.5Gd0.05Fe1.95O4 were prepared using sol-gel method. In order to study effect calcination temperature on optical parameters, powder was divided into five parts. first part taken as as-prepared sample and remaining four parts calcinated at different temperatures, 600°C, 700°C, 800°C & 900°C. X-ray diffraction patterns revealed formation cubic spinel structure with single phase Fd3m space group. crystallite size increased from 11.75 nm 18.13 600 900°C whereas exhibited 17.61 nm. dislocation density decreased 7.243 × 10-3 3.042 nm-2 600°C micro strain 10 10-4 6.452 characteristic absorbance peaks obtained 255.2 for it 252.8 700°C there no such peak in UV-visible range 900°C; is expected below 200 region. energy gap calculated Kubelka-Munk equation based Tauc’s plot found 4.100 eV 5.389 eV. lowest by highest It concluded that tunable band gaps can be varying temperature.