Synergistic Interface and Entropy Engineering in Ferrite/Nitrides Heterogeneous High-Entropy Composites for Broadband Microwave Absorption

The rational design of heterogeneous interfaces combined with high-entropy configuration plays a critical role in tailoring microwave absorption mechanisms, paving the way for developing advanced absorbing materials with exceptional performance. Herein, we propose a novel material paradigm of high-entropy ferrite/nitrides heterogeneous composites to achieve broadband absorption. A series of these composites were synthesized via chemical co-precipitation and subsequent controlled nitridation of multi-cation spinel precursors. This strategy ingeniously integrates entropy engineering and heterogeneous interface construction. The highentropy configuration enables precise dielectric tuning, while the in-situ formed iron nitrides (Fe 4 N, FeN) enhance conductive loss and create abundant interfaces for intensified polarization. Coupled with multi-mode magnetic loss mechanisms, these synergistic effects empower the composites with exceptional absorption capabilities. A remarkable minimum reflection loss of -62.38 dB is attained, and an effective absorption bandwidth of 6.72 GHz is obtained at a thin matching thickness of 1.9 mm. Furthermore, a macroscopic gradient metamaterial designed with these composites accomplishes an ultra-broad bandwidth of 13.81 GHz with a total thickness of merely 5.6 mm. This work advances the synergistic integration of entropy engineering and heterogeneous interface construction, providing valuable inspiration for developing next-generation multi-component microwave absorption materials.