A DFT study of the structural, magnetic, electronic, mechanical and optical properties of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites: Optoelectronic applications

DFT calculations were used to investigate the structural, magnetic, electronic, mechanical and optical properties of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites by employing the CASTEP Code. The simulated XRD of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites revealed an increase in lattice constants (8.353–8.501 Å), d-spacings (2.426–2.592 Å), the volume of the unit cell (582.811–614.342 Å3), hopping lengths (LA = 7.234–7.441 Å; LB = 5.906–6.074 Å) and a decrease in X-ray density (5.376–5.035 g/cm3). The M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites exhibited the characteristics of direct bandgap semiconductor materials, which increased from 0.931–1.176 eV The computed DOS revealed that M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites exhibited good spin polarization behavior as well, and according to Hirshfeld analyses, the magnetic moment from 3.348–1.436 μB and saturation magnetization from 79.264–34.435 emu/g were increased. The cubic crystal mechanical stability criteria of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites indicated that all ferrites were mechanically stable as potential candidates in electrochemical applications. The values of Pugh's ratio of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites predicted the ductile nature of all ferrites and all the values of Poisson's ratio exhibited the behavior of ionic bonds of all ferrites. The optical characteristics of M0.75Cu0.25Fe2O4 (M = Co, Ni, Mg, Mn) ferrites lie in visible regions, which proved suitable candidates in optoelectronic applications.