Comprehensive Analysis of Aluminum-Substituted Lithium Nano Ferrites Using Experimental and DFT Approaches

Abstract

The sol–gel auto-combustion approach prepared compounds of aluminum-substituted lithium ferrites nanocrystalline (Li_0.5Al_xFe_2.5−xO₄, where x = 0.0–0.8, step 0.2). X-ray diffraction (XRD) investigation validated the cubic phase spinel structure and revealed that the lattice constant altered drastically, particularly for the sample x = 0.6, which reduced dramatically, while the crystallite size decreased and reached roughly 5 nm for sample x = 0.8. The variation of the electronic structure leads to a change in the band gap of LiAl ferrite due to the replacement of Al by Li ferrite with distinct electronic configurations. The Spin-polarized Density Functional Theory (DFT) simulation was performed to demonstrate the electronic and optical properties of the Li-Al ferrites. The lattice parameters of the optimized structures and the band gap were consistent with the experimental data. A noticeable band gap was observed, and anisotropy was found in the spin contributions of the band structure and density of states, demonstrating the potential of lithium ferrites for photovoltaic and spintronic applications.