In this study, a series of Cu1-xNixFe2-xLaxO4 ferrites were synthesized utilizing the sol–gel citrate-nitrate method. The results demonstrated that selective Ni/La cation substitution can efficiently modify the structural, elastic, and magnetic properties of the copper ferrite. An examination of lattice parameters revealed a simultaneous decrease in the lattice parameter of a and an increase in the lattice parameter of c as Ni/La co-substitution increased, signifying a structural transition from a tetragonal structure with space group I41/amd to a cubic structure with space group Fd \(\bar{3}\) m. This transition can be attributed to the impacts of ionic substitution on lattice geometry and symmetry. Elastic parameter measurements displayed a progressive decrease in their values as Ni/La substitution increased, indicating a weakening of the ionic bond within the spinel ferrite structure. This weakening is likely a result of differences in electronegativity and ionic radii between the substituting ions (Ni, La) and the host ions (Cu, Fe). Magnetic analysis unveiled a hard-to-soft phase transition upon increasing the Ni/La co-substitution. This transition was marked by a decrease in the coercivity (Hc) and an increase in the saturation magnetization (Ms) of the Cu1-xNixFe2-xLaxO4. The reduction in the Hc from 750 to 420 Oe for x = 0.0 and 0.10, respectively, suggests diminished magnetic anisotropy. Notably, the Ms of the samples peaked at 35.67 emu/g for sample x = 0.08, illustrating that the magnetic properties can be fine-tuned through Ni/La co-substitution.
Graphical Abstract
