Highly-enhanced microwave absorption of Fe@CNTs/PrFeO3 composites from conductive CNTs and magnetic Fe nanoparticles

Abstract

The Fe@CNTs/PrFeO₃ composites were synthesized via chemical vapor deposition (CVD) using PrFeO₃ nanoparticles as catalysts, which facilitated the simultaneous formation of Fe nanoparticles and growth of carbon nanotubes (CNTs) on the PrFeO₃ surface, with both processes exhibiting time-dependent enhancement under prolonged CVD duration. These composites demonstrate exceptional microwave absorption (MA) performance, particularly sample S2 (2 min CVD) which achieves an optimal minimum reflection loss of −53.25 dB at 6.56 GHz with 4 mm thickness, attributable to synergistic effects between the constituent materials. The outstanding performance stems from three primary mechanisms: (1) multi-component effects including enhanced multi-interface scattering/refraction from heterogeneous structures and optimized impedance matching that promotes efficient microwave penetration and dissipation; (2) CNTs-induced dielectric loss through strong dipole/interface polarization and conductive loss from the percolating network; and (3) Fe nanoparticle-mediated magnetic loss via natural resonance, exchange resonance, and eddy current effects at elevated frequencies. This unique combination of dielectric and magnetic loss mechanisms, coupled with favorable impedance matching, accounts for the superior MA properties of the Fe@CNTs/PrFeO₃ composites.