Studying the effect of calcination on optical and magnetic properties of NiFe2O4@Ti-doped ZnO nanoparticles

A novel magnetically separable NiFe2O4@Ti-doped ZnO nanosphere was synthesized using the heterogeneous nucleation of Ti-doped ZnO nanoparticles on NiFe2O4 polycrystalline nanospheres by hydrothermal method. Structural and microstructural properties of synthesized polycrystalline nanospheres were studied by X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR), Field emission scanning electron microscopy (FESEM) with an energy-dispersive X-ray spectrometer (EDX), and Transmission electron microscopy (TEM). The effect of calcination on optical and magnetic properties is also investigated. The optical properties of synthesized nanoparticles were investigated using UV-vis spectroscopy which shows the absorption peak in the visible region. The band gap energy of pure ZnO, Ti-doped ZnO, and NiFe2O4@Ti-doped ZnO before and after calcination was calculated 3.21 eV, 2.92 eV, 2.44 eV, and 2.04 eV, respectively. A vibrating sample magnetometer (VSM) was employed to study magnetic features that the saturation magnetization (Ms) of NiFe2O4 and NiFe2O4@Ti-doped ZnO non-calcined and calcined was obtained 63.6 emu/g, 21.3 emu/g, and 15.3 emu/g, respectively. Hence, the results represented that the calcination of NiFe2O4@Ti-doped ZnO nanosphere improved the optical properties and reduced the band gap energy. However, NiFe2O4 combination with nonmagnetic matrix and calcination of NiFe2O4@Ti-doped ZnO nanoparticles decrease the saturation magnetization (Ms) value and response to the external magnetic field.