Investigations on electronic, magnetic, and optical properties of MnFe₂O₄ through first-principles calculations

MnFe₂O₄ represents a notable spinel ferrite material that synergistically combines the benefits of both Fe- and Mn-based materials. This compound emerges as a potential candidate for diverse applications encompassing biomedical techniques like thermotherapy, energy storage mechanisms such as lithium-ion batteries and supercapacitors, and advancements in optoelectronics and optical devices. Comprehensive first-principles calculations have been employed to delve into the structural, electronic, magnetic, and optical properties of MnFe₂O₄. The intricate chemical interaction of Mn-O and Fe-O is elucidated via charge and spin features. This study meticulously examines distinct energy bands, spatial charge distributions, specific van Hove singularities, and configurations separated by spin orientation. Preliminary findings categorize the material as a semiconductor exhibiting ferrimagnetic traits. Among the computational methodologies utilized, including local-density approximations (LDA), LDA + U, Perdew, Burke, Ernzerhof (PBE), and PBE + U, the latter method shows a band gap of 1.017 eV, in contrast to the narrower gaps identified by alternative approaches. Crucially, the pronounced multi-orbital interactions spanning [4s, 3d_x²-y² 3d_xy, 3d_yz, 3d_xz, 3d_z²] and [2s, 2p_x, 2p_y, 2p_z] offer insights into the fundamental physicochemical interactions of Fe-O and Mn-O. This article also presents and deliberates on the optical properties, emphasizing peaks that correlate directly with band structures and spin configurations.