CoFe₂/BaTiO₃ Hybrid Nanofibers for Microwave Absorption

Abstract

CoFe 2 /BaTiO 3 hybrid nanofibers (CoFe 2 /BTO HNFs) have been synthesized via a simple single-spinneret electrospinning followed by a calcination and hydrogen-thermal reduction process for microwave absorption. Electromagnetic and microwave absorption properties of CoFe 2 /BTO HNFs with different compositions are compared with those of pure CoFe 2 NFs and BTO NFs. The results reveal that the CoFe 2 /BTO HNFs with a CoFe 2 /BTO molar ratio of 7:3 exhibit superior microwave absorption properties with a higher intensity and a wider bandwidth at a smaller absorber thickness. An optimal reflection loss (RL) of −82.4 dB at 15.2 GHz and an effective absorption bandwidth (RL ≤ −20 dB) of 5.0 GHz (13.0−18 GHz) are obtained for a thin thickness of only 1.2 mm. Moreover, the absorption band with RL values less than −20 dB can be manipulated between 4.6 and 18 GHz through changing the coating thickness in the range 1.0−3.0 mm. The excellent microwave absorbing performance can be mainly attributed to the better balance between impedance matching and electromagnetic attenuation capacity deriving from the good synergistic effect between dielectric BTO and magnetic CoFe 2 nanoparticles within a such one-dimensional hybrid heteronanostructure as well as the significantly improved interfacial polarization relaxation. Furthermore, the three-dimensional network structure interlinked by these HNFs also contribute to microwave absorption through additional dissipation pathways such as microcurrent, multiple reflections, and scattering. The optimized CoFe 2 /BTO HNFs may be a potential candidate for lightweight and highly efficient microwave absorbing materials.

High-Performance, Lightweight, and Flexible Thermoplastic Polyurethane Nanocomposites with Zn2+-Substituted CoFe2O4 Nanoparticles and Reduced Graphene Oxide as Shielding Materials against Electromagnetic Pollution

“…It leads to the transformation between the permittivity and permeability; consequently, the increase in the value of ε″, in turn, causes a decrease in the value of μ″ and becomes negative. 103 Furthermore, for the comparative analysis of the dielectric loss abilities of the prepared nanocomposites, the dielectric loss tangents (tan δ ε = ε″/ε′) is evaluated. The dielectric loss (tan δ ε ) of CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU nanocomposites is depicted in Figure 10c.…”

“…In general, negative imaginary permeability is noticed in carbonaceous/magnetic composite materials. , The observed negative imaginary permeability is associated with the radiated magnetic energy intensively converted into electric energy. It leads to the transformation between the permittivity and permeability; consequently, the increase in the value of ε″, in turn, causes a decrease in the value of μ″ and becomes negative …”

“…In general, it is noticed that it is difficult for a traditional shielding material to receive satisfactory shielding performance due to the poor impedance matching for the individual magnetic and dielectric electromagnetic wave absorber materials . Consequently, remarkable attempts have been done to create high-performance composite shielding materials consisting of both magnetic and dielectric components, which would provide better impedance matching and enhanced electromagnetic shielding performance through the effective complementarities and synergies between magnetic loss and dielectric loss. , Further, lightweight and flexible polymer nanocomposites as electromagnetic interference shielding materials have received a lot of attention among researchers due to several other advantages such as corrosion-protection, large-area fabrication, low cost, etc . Polymer nanocomposites with dielectric and magnetic fillers can exhibit fascinating results within the development of high-performance shielding materials.…”

FeCo/ZnO Composite Nanofibers for Broadband and High Efficiency Microwave Absorption

“…[ 10 ] In general, the magnetic loss mainly derives from the eddy current loss, natural resonance and exchange resonance in microwave bands. [ 17 ] If the magnetic loss only arises from the eddy current loss, the values of C 0 (μ″( μ′ ) –2 f –1 ) should be constant as the frequency is varied. However, as shown in Figure 2d, the C 0 values always change with frequency in our case, suggesting that the eddy current loss can be neglected.…”

BaTiO3@C Core–Shell Nanoparticle/Paraffin Composites for Wide-Band Microwave Absorption

“…Generally, ideal microwave absorbing materials are expected to be lightweight, stable, and efficient . Previous investigations have devoted much effort to developing magnetoelectric materials as absorbers by unifying the dielectric and magnetic loss simultaneously . Through the synergistic effects between the magnetic and dielectric components, excellent microwave absorption properties could be obtained due to the large magnetic/dielectric loss and the improved impedance matching .…”