Structural and Magnetic Properties of CoFe2O4 Nanoparticles Synthesized by Starch-Assisted Sol–Gel Auto-Combustion Method in Air, Argon, Nitrogen and Vacuum Atmospheres

In the present work, structural and magnetic properties of CoFe2O4 nanoparticles synthesized by starch-assisted sol–gel auto-combustion method in air, argon, nitrogen and vacuum atmospheres were investigated. The particle size, shape, crystal structure and magnetic properties of synthesized ferrite nanoparticles were investigated by powder X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), Raman spectrometer, Fourier transform infrared spectroscopy (FTIR) and a vibrating sample magnetometer (VSM). The FE-SEM micrographs indicate the octahedron-like cobalt ferrite nanoparticles formation in air atmosphere; however, spherical nanoparticles were formed in argon, nitrogen and vacuum atmospheres. An infrared spectroscopy study showed the presence of two absorption bands in the frequency range around 560 cm−1 (ν1) and around 340 cm−1 (ν2) which indicated the presence of tetrahedral and octahedral group complexes, respectively, within the spinel lattice. Room temperature magnetization measurements showed that the saturation magnetization (Ms) and coercivity (Hc) were influenced by cobalt ferrite formation atmosphere, i.e., air, argon, nitrogen and vacuum.