Advances in iron-based electromagnetic wave absorbers: multiscale engineering from atomic defects to macroscopic architectures for performance optimization

The rapid development of electronic devices and communication technologies has caused increasingly severe electromagnetic wave (EW) pollution. The development of efficient EW absorption (EWA) materials is essential to protect human in the modern society. Iron (Fe)-based EWA materials have garnered significant attention owing to their cost-effectiveness, high saturation magnetization, and superior magnetic loss capabilities. This review article begins with an introduction of Fe-based EWA materials, followed by briefly introducing the EWA mechanism of Fe-based materials. Then, various pristine iron-based absorbers such as carbonyl iron powder, ferrite-based materials, iron-based alloys, iron-based high-entropy alloys, and Fe-based MABs are systematically reviewed. Strategies including doping, in-situ oxidation, porous structure and composite construction for enhancing the performance of Fe-based composite absorbers are critically discussed. Conclusions and perspectives demonstrate the synergy between Fe-based and high-entropy (HE) materials to unlock next-generation EWA materials for applications in stealth technology, wearable electronics, and harsh-environment systems.