Broad microwave absorption bandwidth achieved by exchange coupling interaction between hard and soft magnetic materials

Abstract

To gain broad microwave absorption bandwidth over 2–18 GHz, hard/soft magnetic composites Ba(Zr–Ni)0.6Fe10·8O19/Fe3O4 have been synthesized in this work. The results show that the raising heat treatment temperature would cause more Fe3O4 particles attach to Ba(Zr–Ni)0.6Fe10·8O19 particles, increasing the number of interfaces between Ba(Zr–Ni)0.6Fe10·8O19 and Fe3O4 to enhance the hard/soft exchange coupling effect. Finally, the sample heat treated at 400 °C possesses the widest magnetic loss range (μ″>0.2) of 12.4 GHz, which contributes to a broad effective absorbing bandwidth of 6.68 GHz at 1.9 mm. The performance is superior than most of the state-of-the-art microwave absorbers.