Magnetic response of environmentally friendly prepared La3+ doped Li-Cu spinel ferrites

• La 3+ doped Li-Cu SFs were synthesized via the self-ignition method. • With La 3+ substitution, reducing crystallite size (29.1 nm – 17.3 nm) and particle size (42 nm – 22 nm). • Saturation magnetization (60 – 23 emu/g) and coercivity (1331 – 639 Oe) decreased, enhancing magnetic softness. • The microwave operating frequency (ω m ) decreased, indicating tunable dynamic magnetic behavior. • These materials are suitable for recording media, memory devices, and transformer cores. In this study, the Li 0.1 Cu 0.5 Fe 2.3–y La y O 4 (y = 0.0, 0.1, 0.2, 0.3, 0.4) spinel ferrites (SFs) were synthesized via self-ignition route, and their structural, morphological, compositional and magnetic properties were systematically analyzed. X-ray diffraction (XRD) analysis revealed a slight shift in the (311) diffraction peak position with increasing La 3+ concentration, indicating lattice distortion. The crystallite size (D) decreased from 29.1 nm to 17.3 nm with doping, while lattice constant (a) and unit cell volume (V) exhibited a decreasing trend, confirming structural modifications due to La 3+ addition in Li-Cu spinel lattice. Moreover, the particle size was also decreased from 42 nm to 22 nm with the substitution of La 3+ . Magnetic response demonstrated a significant reduction in saturation magnetization (M S ), from 60 emu/g to 23 emu/g, and coercivity (H C ), from 1331 Oe to 639 Oe, suggesting weakened magnetic interactions. The squareness ratio (SQ) increased, while the magnetocrystalline anisotropy constant (K) decreased, indicating enhanced magnetic softness. Furthermore, the microwave operating frequency (ω m ) was also reduced with La 3+ doping, highlighting changes in dynamic magnetic behavior. These findings suggest that La 3+ doping effectively tailors the structural and magnetic properties of Li-Cu SFs, making them potential candidates for tunable magnetic applications including recording media, memory devices, and transformer core applications.