Theoretical and experimental investigation of NiFe2O4 and CaMnO3 nanoparticles to study their structural, magnetic, and polarization properties for energy-related applications

This work presents a comparative theoretical and experimental investigation of spinel nickel ferrite (NiFe2O4) and perovskite calcium canganite (CaMnO3) nanoparticles synthesized via the sol-gel method. NiFe2O4 samples were calcined at temperatures ranging from 400 to 1000 °C, and the CaMnO3 samples were calcined at temperatures ranging from 300 to 600 °C. X-ray diffraction (XRD) confirmed the formation of both materials, and the highest peak was observed at 2θ = 35.816° for NiFe2O4 and 2θ = 32.45° for CaMnO3, with Miller planes (311) and (121), respectively. Using the Scherrer formula, the best crystalline size of nickel iron oxide was found to be 25.03 nm, and of calcium manganese oxide was 14.65 nm. Structural properties were also calculated theoretically using the Quantum Espresso code and compared with the XRD results. Moreover, field-emission scanning electron microscopy (FESEM) was used for morphological analysis, the results were further processed to calculate the particle size distribution. Polarization and magnetic properties were analyzed using a multiferroic testing machine and a vibrating sample magnetometer (VSM), respectively. The hysteresis loop of NiFe2O4 showed a saturation magnetization of 29.61 emu/g, making it a strongly ferromagnetic material compared to CaMnO3, which had 1.71 emu/g.