Electromagnetic wave absorption superalloy/graphite magnetic nanocapsules applied in wide temperature range

The magnetic nanocapsules composed of soft-magnetic core and dielectric graphite shell in nanoscale are of great significance for electromagnetic wave (EMW) absorbing materials. As an ideal model system, novel nano composite superalloy/graphite FeNi3@C nanocapsules were synthesized that showed two significant advantages including extremely stable magnetic behavior from 5 K to 300 K and strong anti-oxidation ability up to 719 K, simultaneously. The tuning regularity of enhanced EMW absorption, including magnetic core, filling ratio, dielectric shell, was systemically investigated. A reflection loss (RL) -47.26 dB at 13 GHz and an absorption bandwidth 7.04 GHz (RL <-10 dB) with absorber thicknesses 3 mm were obtained while the effective absorbing bandwidth remained at top level in magnetic nanocapsules system. This work not only extends EMW absorption application of magnetic nanocapsules in wide temperature range, but also provides a clear optimal sequence to support the material design strategy to achieve best EMW absorption in nanocomposite systems.