Excellent microwave absorption of Fe3O4/Ag composites attained by synergy of considerable magnetic loss and dielectric loss

Abstract

Urgent demands to reduce the harmful electromagnetic radiation and improve weapons survivability made it necessary to develop high-efficiency microwave absorption materials, especially those operating in frequency range of 2–12 GHz. In this work, Fe3O4/Ag composites were synthesized by one-step hydrothermal method. Microwave absorbing performance can be flexibly tuned by varying Fe3O4/Ag molar ratio from 2:1, 3:1, to 4:1. An increase in Fe3O4/Ag molar ratio would lead to an enhanced permeability over the frequency region of 4–12 GHz. Meanwhile, real part of permittivity remains almost unchanged whereas the imaginary part drastically decreases, making impedance matching and attenuation capacity increase dramatically. In this way, splendid microwave absorption performance with broad absorption bandwidth within a range of 4.88–9.76 GHz and minimum reflection loss of −63.2 dB could be achieved at composite thickness of 3.6 mm.