Synergistic interface and entropy engineering in ferrite/nitride heterogeneous high-entropy composites for broadband microwave absorption

Abstract

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/nitride 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 high-entropy configuration enables precise dielectric tuning, while the in situ formed iron nitrides (Fe₄N and FeN) enhance conductive loss and create abundant interfaces for intensified polarization. Coupled with multi-mode magnetic loss mechanisms, these synergistic effects endow 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.