NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2021, 12 (4), P. 481–491
Study of magnetic and optical transitions in MFe2O4 (M=Co, Zn, Fe, Mn) with spinel structure
Nitika – Department of Physics, SRM University, Delhi NCR, Sonepat, 131029, India; email@example.com
Anu Rana – Department of Physics, SRM University, Delhi NCR, Sonepat, 131029, India
Vinod Kumar – Department of Physics, NSUT, Dwarka, New Delhi, 110078, India
Spinel ferrite (MFe2O4) nanoparticles were successfully synthesized by the coprecipitation method. X-ray diffraction technique was employed for structural analysis. Single-phase cubic spinel structure with an average crystallite size ranging from 5 – 20 nm was obtained for the prepared ferrites. The Fourier transform infrared spectra exhibits an absorption band at 550 cm-1, which is attributed to metal-oxygen bond vibrations at tetrahedral sites. The thermogravimetric analysis revealed the instability of MnFe2O4 and Fe3O4 above 500 °C whereas CoFe2O4 is found to be the most stable ferrite. The hysteresis parameters demonstrate the superparamagnetic nature of the prepared nanoparticles with low coercivity except for CoFe2O4. The direct optical band gap energy derived from UV-visible spectra is calculated to be 2.82, 2.83, 2.81, and 2.44 eV for M=Co, Zn, Fe, and Mn respectively. The magnetic and optical properties show a strong dependence on cation site occupancy.
Keywords: Spinel ferrites, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, hysteresis curve, optical properties.