Studying the Effect of Calcination on the Optical and Magnetic Properties of NiFe2O4@ZnO:Ti Nanoparticles

In this study, novel magnetically separable NiFe2O4@ZnO:Ti nanospheres were synthesized using the heterogeneous nucleation of ZnO:Ti (Ti-doped ZnO) nanoparticles on NiFe2O4 polycrystalline nanospheres through the hydrothermal method. Structural and microstructural properties of the synthesized polycrystalline nanospheres were investigated through Fourier-Transform Infrared Spectra (FTIR), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Field Emission Scanning Electron Microscopy (FESEM) using an Energy-Dispersive X-ray (EDX) spectrometer. The effect of calcination on the magnetic and optical properties was also studied. The optical features of the synthesized nanoparticles were recorded using UV-Vis spectroscopy, indicating the absorption peak in the visible region. The band gap energy of pure ZnO, ZnO:Ti, and NiFe2O4@ZnO:Ti before and after calcination was calculated as 3.21 eV, 2.92 eV, 2.44 eV, and 2.04 eV, respectively. Further, Vibrating Sample Magnetometer (VSM) was employed to examine the magnetic features, and the saturation magnetization (Ms) values of NiFe2O4 and NiFe2O4@ZnO:Ti non-calcined and calcined were obtained as 63.6 emu/g, 21.3 emu/g, and 15.3 emu/g, respectively. The findings revealed that calcination of NiFe2O4@ZnO:Ti nanospheres improved the optical properties and reduced the band gap energy. However, NiFe2O4 combination with nonmagnetic matrix and calcination of NiFe2O4@ZnO:Ti nanoparticles decreased the Ms value and response to the external magnetic field.