Improved microwave absorbing properties of core-shell FeCo@C nanoparticles

In this paper, FeCo and FeCo@C nanoparticles are synthesized by using plasma arc-discharging technology. FeCo@C nanoparticles are fabricated by particularly applying methane as a carbon source in the plasma arc-discharging facility. The influences of core-shell nanostructure on magnetic and absorbing properties are investigated. Compared with FeCo nanoparticles, FeCo@C nanoparticles in a typical core-shell structure exhibit lower saturation magnetization, excellent impedance matching and reflection loss (RL) in the GHz frequency range. The optimal RL of −16.8 dB is obtained at 9.9 GHz with the absorber thickness of 3.0 mm. The excellent microwave absorption is attributed to the effective complementarities between dielectric loss and magnetic loss in FeCo@C core-shell nanoparticles.