CoFe₂/BaTiO₃ Hybrid Nanofibers for Microwave Absorption

CoFe2/BaTiO3 hybrid nanofibers (CoFe2/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 CoFe2/BTO HNFs with different compositions are compared with those of pure CoFe2 NFs and BTO NFs. The results reveal that the CoFe2/BTO HNFs with a CoFe2/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 CoFe2 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 CoFe2/BTO HNFs may be a potential candidate for lightweight and highly efficient microwave absorbing materials.