<p>The rapid advancement of high-frequency electronic devices has raised growing public concern regarding electromagnetic pollution, leading to an urgent demand for magnetic materials that exhibit excellent soft magnetic properties alongside low energy loss. In this study, cerium-doped manganese-zinc spinel ferrite Mn_0.6Zn_0.4Ce_<i>x</i>Fe_2-<i>x</i>O₄ (<i>x</i> = 0.000 ~ 0.025) was synthesized using microwave-assisted solid-state sintering. The influence of cerium doping on the structural, microstructural, and magnetic properties of the material was systematically investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and precision impedance analysis (LCR). The results demonstrate that a single-phase manganese-zinc ferrite structure is maintained when the rare earth doping level is <i>x</i> ≤ 0.015. With increasing Ce content, the unit cell volume expands due to the incorporation of larger Ce³⁺ ions into the lattice. The average grain size of the sintered samples ranges from 2.7 to 3.6&#xa0;<i>μ</i>m. FTIR analysis reveals two characteristic absorption bands corresponding to Fe³⁺–O²⁻ vibrations, located between 548.74 and 554.53&#xa0;cm⁻¹ (ν₁) and 418.55&#xa0;cm⁻¹ and 420.48&#xa0;cm⁻¹ (ν₂), respectively, confirming the formation of the spinel ferrite structure. Magnetic measurements show that saturation magnetization and coercivity reach optimal values at a doping concentration of <i>x</i> = 0.020, with saturation magnetization attaining 73.14&#xa0;emu/g and coercivity measuring 5.20 Oe. LCR impedance analysis indicates that cerium doping effectively suppresses the rate of increase of the magnetic loss tangent (tan <i>δ</i>) with frequency. This improvement is attributed to the suppression of eddy current effects, resulting in significantly reduced eddy current losses, thereby enhancing the material’s suitability for high-frequency applications.</p>