Magnetic Behavior, Electromagnetic Multiresonances, and Microwave Absorption of the Interfacial Engineered Fe@FeSi/SiO₂ Nanocomposite

In this study, the interfacial engineered Fe@FeSi/SiO2 nanocomposite has been synthesized by a one-step route of dc arc-discharge plasma. Higher energy states of Ar/Fe/Si ions in the plasma were also diagnosed by means of online optical emission spectroscopy (OES), supplying energetic information on the configuration of Fe@FeSi nanocapsules embedded in SiO2 matrix. It is indicated that the determined electron temperatures of Ar, Fe, and Si ions are 23 513 K (2.02 eV), 23 225 K (2.00 eV), and 23 063 K (1.99 eV), respectively. Electromagnetic parameters display three prominent resonance peaks at 9.7, 14.3, and 16.8 GHz; these are the result of the synergetic effect of heterogeneous interfaces among the Fe@FeSi/SiO2 nanocomposite. The optimized reflection losses at these resonant frequencies are −33, −20, and −38 dB in certain thicknesses, respectively. The excellent microwave absorption of the Fe@FeSi/SiO2 nanocomposite is readily tunable by consequence of the multiresonance behavior and electromagnetic synergetic effect in the interface-rich nanocomposite. The revealed multiresonance phenomena are significant in the design and fabrication of electromagnetic materials as well the correlative devices, with effective absorption losses at distinctive frequencies.