Green synthesis and characterization of NiFe2O4 nanostructure via hydrothermal method

In this paper nickel ferrite nanostructures fabricated via simple and green hydrothermal method using lemon juice. For the synthesis of NiFe2O4 nanoparticles, the materials were placed in the autoclave reactor for 2 and 12 hours. The morphology of particles was studied by scanning electron microscope (SEM). Although the NiFe2O4 nanoparticles after 2 h heating are agglomerated but increasing the heating time to 12 h leads to formation of sphere shape nano size particles. Crystal structure of nickel ferrite nanoparticles was investigated via X-ray diffraction pattern and crystallite size of particles was calculated using Debye-Scherrer formula. The magnetic hysteresis loop of the synthesized ferrite was studied by a vibration sample magnetometer (VSM). The magnetic parameters of remanance Mr, saturation magnetization Ms and coercivity Hc, increase as the synthesis time increases. The optical properties of NiFe2O4 were investigated by ultraviolet visible (UV-vis) spectra. The results show that the particles band gaps decreases with increasing the synthesis time.