<p>This research evaluates the impact of aluminum (Al) substitution on the properties of strontium hexaferrite (SrFe₁₂O₁₉) nanoparticles synthesized via a sol-gel method. A comprehensive suite of characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer Emmett Teller (BET) surface area analysis, vibrating sample magnetometry (VSM), and dielectric measurements were employed. The Rietveld refinement confirmed the formation of a pure hexagonal phase (space group P63/mmc) devoid of any secondary phases. With increasing Al content, a reduction in X-ray density and lattice parameters was observed, which correlates with changes in the Raman spectral features, notably the pronounced A1g peak between 670–710 cm⁻¹. SEM analysis revealed a uniform distribution of grain size. This study also found that greater Al concentrations increase coercivity while reducing both the saturation magnetization and magneton number, reflecting the substitution of nonmagnetic Al³⁺ ions. Additionally, the dielectric properties of both undoped and Al-doped samples demonstrated a typical exponential decline in dielectric constant with increasing frequency, showcasing their potential for various advanced magnetic and electronic applications.</p> Graphical Abstract <p></p>