Defect-engineering-driven synergistic modulation of dual-phase (Fe_0.5Mg_0.5CoNiCuMn)₃O₄@CuO ceramics for superior microwave absorption

To overcome the challenge of insufficient loss strength in single-phase high-entropy ferrites, this work develops a novel defect-engineering-driven dual-phase strategy to fabricate spinel/rock-salt structured (Fe_0.5Mg_0.5CoNiCuMn)₃O₄@CuO composite ceramics. The combination of experimental characterization and first-principles calculations demonstrates a strong positive correlation between the defect concentration and microwave absorption performance. The optimized material achieves outstanding electromagnetic absorption with a minimum reflection loss of −48 dB and an effective absorption bandwidth of 3.9 GHz in the X-band. Remarkably, this work obtains 70% bandwidth retention after oxidation at 1200 °C and a thermal conductivity of 2.154 W·m⁻¹·K⁻¹, demonstrating exceptional high-temperature stability and thermal management capability. This study pioneers a new pathway for the development of oxidation-resistant and electromagnetic protection materials through defect-engineering-driven synergistic modulation.