Studying the Effect of Calcination on the Optical and Magnetic Properties of NiFe۲O۴@ZnO:Ti Nanoparticles

In this study, novel magnetically separable NiFe۲O۴@ZnO:Ti nanospheres were synthesized using the heterogeneous nucleation of ZnO:Ti (Ti-doped ZnO) nanoparticles on NiFe۲O۴ 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 NiFe۲O۴@ZnO:Ti before and after calcination was calculated as ۳.۲۱ eV, ۲.۹۲ eV, ۲.۴۴ eV, and ۲.۰۴ eV, respectively. Further, Vibrating Sample Magnetometer (VSM) was employed to examine the magnetic features, and the saturation magnetization (Ms) values of NiFe۲O۴ and NiFe۲O۴@ZnO:Ti non-calcined and calcined were obtained as ۶۳.۶ emu/g, ۲۱.۳ emu/g, and ۱۵.۳ emu/g, respectively. The findings revealed that calcination of NiFe۲O۴@ZnO:Ti nanospheres improved the optical properties and reduced the band gap energy. However, NiFe۲O۴ combination with nonmagnetic matrix and calcination of NiFe۲O۴@ZnO:Ti nanoparticles decreased the Ms value and response to the external magnetic field.

Keywords:

Magnetic nanoparticles , Heterogeneous nucleation , Hydrothermal method , Band gap engineering , Saturation magnetization