Strong Electromagnetic Wave Response Derived from the Construction of Dielectric/Magnetic Media Heterostructure and Multiple Interfaces

A novel yolk-shell structure of cobalt nanoparticle embedded nanoporous carbon@carbonyl iron (Co/NPC@Void@CI) was synthesized via metal organic chemical vapor deposition (MOCVD) and subsequent calcination treatment. The in situ generation of void layer, which originated from the shrink of a Co-based zeolitic imidazolate framework (ZIF-67) during carbonization, embodies distinct advantage compared to the conventional template method. Thanks to the introduction of custom-designed dielectric/magnetic media heterostructure and multiple interfaces, the composites filled with 40 wt % of Co/NPC@Void@CI samples in paraffin exhibit a maximum reflection loss of -49.2 dB at 2.2 mm; importantly, a broad absorption bandwidth (RL < -10 dB) of 6.72 GHz can be obtained, which covers more than one-third of the whole frequency region from 10.56 to 17.28 GHz. This study not only develops the application of carbonyl iron as a high-efficiency light absorber but also initiates a fire-new avenue for artificially designed heterostructures with target functionalities.