Heterostructured Nanorings of Fe−Fe₃O₄@C Hybrid with Enhanced Microwave Absorption Performance

Abstract

Microwave absorption is a critical challenge with progression in electronics, where fine structural designing of absorbent materials plays an effective role in optimizing their microwave absorption properties. Here, we have developed FeO@C (FC) and Fe-FeO@C (FFC) hybrid nanorings via a hydrothermal method coupled with a chemical catalytic vapor deposition technique. FC and FFC hybrid nanorings have fine carbon coating while their size can easily be tunable in a certain range from 80-130 to 90-140 nm. The optimized FC and FFC hybrid nanorings bear minimum reflection loss (RL) values of -39.1 dB at 15.9 GHz and -32.9 dB at 17.1 GHz, respectively, whereas FFC shows an effective absorption bandwidth (RL values < -10 dB) ranged from 5.2 to 18 GHz. Such an enhanced microwave absorption performance of hybrid nanorings is mainly due to the suitable impedance characteristics, multilevel interfaces, and polarization features in nanorings. This work provides an approach to design hybrid materials having a complex structure to enhance the microwave absorption properties.

Ferromagnetic and excellent microwave absorbing properties of CoNi microspheres and heterogeneous Co/Ni nanocrystallines

“…6. Sample #4 presents the highest attenuation constant in the Ku-band (12)(13)(14)(15)(16)(17)(18), which is consistent with its excellent microwave absorption in the Ku-band (as seen in Fig. 7d).…”

“…Sample #3 presents poor reection loss in the 2-18 GHz range, which can be attributed to the poor impedance matching because its permittivity is much larger than its permeability. However, Sample #4 presents excellent microwave absorption properties in the Ku-band (12)(13)(14)(15)(16)(17)(18) at the coating thickness of 1 mm; the maximum RL value reaches À33 dB at 17.6 GHz and the bandwidth covers the 15.04-18.00 GHz range. As the coating thickness increases to 1.5 mm, the RL peak shis to the position at 11.12 GHz with the maximum RL value of À26.3 dB and the bandwidth covers the 9.8-12.88 GHz range.…”

“…have been synthesized. [5][6][7] To obtain high dielectric loss and optimized impedance matching, multiple-phase structured MAM composites, such as Cu@Ni@RGO, 8 RGO/ BaFe 12 O 19 /Fe 3 O 4 , 9 RGO/CoFe 2 O 4 /ZnS, 10 PANI/a-Fe 2 O 3 @SiO 2 , 11 Co/CoO, 12 CoNi@C/RGO, 13 and Fe-Fe 3 O 4 @C, 14 have been widely investigated. However, to the best of our knowledge, heterogeneous ferromagnetic metal nanocrystalline MAMs have been seldom investigated.…”

Nanoporous Copper Pattern Fabricated by Electron Beam Irradiation on Cu3N Film for SERS Application

“…LSPRs supported by copper nanoporous structures are revealed by numerical simulations which shows intense electromagnetic field enhancements around nanopores. Compared with other hollow‐core and porous structures enabled by dedicated synthesize or growth methods, our work provides an efficient strategy to prepare copper nanoporous structures, which is potentially very promising in developing SERS platforms and optofluidic sensing systems for molecular diagnostics in future.…”

Preparation and Microwave Absorption Properties of NixSy/PVDF Nanocomposites

“…In recent years, many nanomaterials have been proved to exhibit excellent absorbing properties, such as Fe 3 O 4 (Jia et al, 2010), SiC (Kuang et al, 2019), RGO aerogels (Zhang M. et al, 2019), C@CoFeO@MnO 2 (Feng et al, 2020), Fe 3 O 4 @NPC (Xiang et al, 2019), and PbS (Pan et al, 2017). In addition, many studies have shown that most of the nanocomposites have synergistic effects, which will be very beneficial to the absorbing properties of the materials (Liu et al, 2017;Jian et al, 2018;Ma et al, 2018). The typical composites are composed of matrix and filler.…”