Improvement of Structural, Elastic, and Magnetic Properties of Vanadium-Doped Lithium Ferrite

The influence of vanadium substitution on the structure, elastic, mechanical, and magnetic behavior of lithium ferrite (Li0.5+xVxFe2.5−2xO4; x = 0.00–0.2) was systematically studied. X-ray diffraction (XRD) was used to investigate the crystal structure, and infrared spectroscopy (IR) was used to determine the cation distribution between the two ferrite sublattices, in addition to the elastic and mechanical behavior of Li0.5+xVxFe2.5−2xO4 ferrites. X-ray analysis revealed a monotonic decrease in lattice parameter from 8.344 Å to 8.320 Å with increasing V5+ content, confirming lattice contraction and stronger metal–oxygen bonding. Despite a moderate increase in porosity (from 6.9% to 8.9%), the elastic constants C11 and C12 increased, indicating improved stiffness and reduced compressibility. The derived Young’s, bulk, and rigidity moduli rose with the doping of V5+. Correspondingly, the longitudinal, shear, and mean velocities (Vl, Vs, and Vm) increased. The Debye temperature also showed a linear rise from 705 K to 723 K with V5+ doping, directly reflecting enhanced lattice stiffness and phonon frequency. Furthermore, both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased. Curie temperature (TC) decreased with increasing V5+ concentration, while both the saturation magnetization (MS) and the initial permeability (μi) increased up to V5+ concentration x = 0.1 and then decreased, while the coercivity (HC) showed the reverse trend. These results confirm that V5+ incorporation significantly enhances the Li ferrite, improving its elastic strength, lattice energy, thermal stability, and magnetically controlling properties and making them suitable for a variety of daily uses such as magneto-elastic sensors, high-frequency devices, and applications requiring mechanically robust ferrite materials.