Whereas hollow composites present some superiorities like abundant micro interfaces, outstanding impedance matching as the responses of electromagnetic wave (EMW), but versatile designs including crystal transformation, heterogeneous structures and magnetic exchange coupling to further contribution are even not designed or stressed together in previous literatures. In this article, rational design on the hollow CoFe₂O₄/CoFe@C architecture has been conducted by a sequential process of self-sacrifice by combustion, in-suit polymerization and calcination. Results of morphology observation exhibit that heterogeneous CoFe₂O₄/CoFe@C composites were generated via crystal transformation from CoFe₂O₄ to CoFe alloys with encapsulated carbon, together with ultimate growth of crystal particles. As for three carbon-based architectures, relatively low-graphitization carbon layers are favorable for enhancing impedance matching and polarization relaxation, but suppressing the conductive loss essentially. Moderate carbon content endows sample S2 with the maximum magnetic saturation (M_s) of 152.4 emu g^-1. The optimized RL of sample S3 is up to -51 dB with 30 wt% loading, and the effective absorption band (EAB) is of 5.9 GHz at the thickness of 2.17 mm, while 6.0 GHz can be reached at 2.5 mm. Therefore, this hollow multi-interfaces design definitely shed light on novel structure for new excellent absorbers.

中空复合材料具有一些优势，例如丰富的微界面，出色的阻抗匹配（作为电磁波（EMW）的响应），但是在以前的文献中甚至没有一起设计或强调包括晶体转变，异质结构和磁交换耦合等更多用途的通用设计。 。在本文中，已经通过燃烧，内聚和煅烧的自我牺牲的顺序过程对空心CoFe ₂ O ₄ / CoFe @ C结构进行了合理的设计。形态观察结果表明，通过CoFe ₂ O _4的晶体转变生成了异质CoFe ₂ O ₄ / CoFe @ C复合材料。含碳包裹的CoFe合金，以及晶体颗粒的最终生长。对于三种基于碳的体系结构，相对低石墨化的碳层有利于增强阻抗匹配和极化弛豫，但实质上抑制了导电损耗。适度的碳含量使样品S2的最大磁饱和度（M _s）为152.4 emug ^-1。样品S3的优化RL在负载为30 wt％时高达-51 dB，在2.17 mm的厚度处有效吸收带（EAB）为5.9 GHz，而在2.5 mm处可以达到6.0 GHz。因此，这种中空的多界面设计无疑为新型优秀吸收体的新颖结构提供了启发。