Development of ultra-thin and high-efficient bi-layer microwave absorbers from Fe3N@C and CoS2 samples.

Nowadays, electromagnetic interference (EMI) is one of the pollution that harm human health and electronic devices. Iron nitride (Fe 3 N) and cobalt sulfide (CoS 2) are promising microwave-absorbing materials (MAMs) due to their intriguing properties. In this work, polygonal Fe 3 N@C and flower-like CoS 2 were fabricated, and Fe 3 N@C showed pretty good magnetic properties. Microwave absorption properties of as-prepared samples were investigated, where Fe 3 N@C and CoS 2 reached minimum reflection loss (RL) of −12 dB and −23 dB, respectively. In addition, Fe 3 N@C mostly had no effective absorption bandwidth (EAB), whereas Co 2 S was 2.5 GHz. The better microwave absorption properties of CoS 2 compared to Fe 3 N@C could be explained through the combination of electrical conductivity, C 0 values, loss capacity matching, impedance matching, and attenuation constant. It is worth mentioning that both Fe 3 N@C and CoS 2 could not be considered promising MAMs. Therefore, RL curves of bi-layer MAMs made from as-prepared samples were simulated, where CoS 2 and Fe 3 N@C acted as absorption and matching layers, respectively. The simulated Fe 3 N@C/CoS 2 = 0.6 mm/0.6 mm bi-layer absorber could reach an RL of −45 dB and an EAB of 13 GHz, which was superior to the single-layer ones. The fabricated Fe 3 N@C/CoS 2 = 0.6 mm/0.6 mm bi-layer absorber confirmed these excellent properties, which could be a result of the enhancement of complex permittivity, complex permeability, dielectric, and magnetic loss tangents. [ABSTRACT FROM AUTHOR]