Structural, electronic, magnetic, and optical properties of MFe2O4 (M = Ni, Fe, Co) spinel ferrites: A density functional theory study

The structural, electronic, magnetic, and optical properties of MFe2O4 (M = Ni, Fe, Co) ferrites were investigated by employing Cambridge Serial Total Energy Package code using density functional theory. LDA+U was used to investigate the structural, electronic, magnetic, and optical properties of MFe2O4 (M = Ni, Fe, Co) ferrites at different pressures 0, 5, 10, 15, and 20 GPa. The simulated X-ray diffraction (XRD) pattern of MFe2O4 (M = Ni, Fe, Co) ferrites was investigated and the computed lattice parameters decreased 8.62-8.32, 8.68-8.35, and 8.567-8.267 angstrom at 0-20 GPa, respectively. XRD revealed that the unit cell's volumes (640.50-575.93, 653.97-582.182, 627.22-563.550), X-ray densities (4.86-5.40, 4.70-5.28, 3.97-4.43), and interatomic distance (2.6099-2.5180, 2.6221-2.4260, 2.5831-2.4928) of MFe2O4 (M = Ni, Fe, Co) ferrites were also decreased with the increasing pressure 0-20 GPa, respectively. The LDA+U calculations predicted that the NiFe2O4, Fe3O4, and CoFe2O4 ferrite followed the properties of a semiconductor exhibiting a direct band gap of 1.2, 1.13, and 0.710 eV at 0 GPa which were decreased to 0.846, 0.710, and 0.461 eV at 20 GPa, respectively. The computed density of states revealed that MFe2O4 (M = Ni, Fe, Co) ferrites exhibited good spin polarization behavior, and Ni-O, Fe-O, and Co-O bonds were covalent. The Mullikens investigated the ted decrease in bong length of MFe2O4 (M = Ni, Fe, Co) ferrites versus 0-20 GPa as well as according to Hirschfeld analysis the magnetic moment (3.348-3.335, 4.12-4.10, 3.737-3.735) and saturation magnetization (79.06-78.7, 99.33-98.9, 88.93-88.352) of MFe2O4 (M = Ni, Fe, Co) ferrites were decreased with increased pressure 0-20 GPa, respectively. The reflectivity and absorption specialize in visible and ultraviolet regions showing their stability for optoelectronics, photocatalysis, and solar cell applications.