Construction of FeNi3 and core-shell structured FeNi3@C microspheres toward broadband electromagnetic wave absorbing

The rational design of electromagnetic wave absorption (EMA) materials featured with broadband and high-efficiency in gigahertz (GHz) is still a great challenge. In this study, we prove fabricating FeNi3 and FeNi3@C core-shell microspheres to solve the challenge. The as-prepared FeNi3 microspheres exhibits extremely broad effective absorption bandwidth (EAB, RL >= 10 dB, > 90 % absorbing) of 10.3 GHz (7.7-18.0 GHz) at only 2.0 mm, occupying 64.4 % of the investigated frequency range with a single matching thickness. Such an outstanding EMA performances is credited to strong dielectric loss and magnetic loss. Compared with pristine FeNi3, the delicate design of core-shell structure and tailored synergistic effect of FeNi3 and carbon produce positive reinforcement both in magnetic loss and dielectric loss, endowing FeNi3@C samples with optimized impedance matching and appropriate attenuation ability. As a result, FeNi3@C samples present impressive EMA performances from C to Ku band, especially for FeNi3@C-3, demonstrating its potential of effectively dissipates electromagnetic wave in 6.1-18.0 GHz (RL >= 20 dB, > 99 % absorbing) by simply regulating a thickness of 1.5-2.5 mm. FeNi3 and FeNi3@C feature with optional broad bandwidth (completely covering C, X and Ku band), strong absorption, and thin thickness ensure them a superior EMA material.

Automated summary

This study demonstrates the rational design of FeNi3 and FeNi3@C core-shell microspheres for efficient electromagnetic wave absorption in the gigahertz range. The delicate design and synergistic effect of FeNi3 and carbon contribute to impressive absorption performance in the C to Ku band.