Broadband and high-efficiency electromagnetic wave absorption by Bi2Fe4O9/Fe3O4 nanoflowers

The demand for high-performance electromagnetic wave absorbent materials continues to grow with advancing technology. This study reports the synthesis of Bi2Fe4O9/Fe3O4 nanoflower to enhance electromagnetic wave absorption. Bi2Fe4O9, synthesized via a hydrothermal method, was composited with different content Fe3O4 nanocrystals. The strong binding between sheets of nanoflowers provides large surface area and active sites for electromagnetic wave absorption (EMA). The combination of Bi2Fe4O9 and Fe3O4 markedly enhanced the dielectric and magnetic properties, resulting in exceptional EMA performance. The sample achieved a minimum reflection loss (RLmin) of-75 dB at 7.0 GHz with a thickness of just 2.5 mm, along with a maximum effective absorption bandwidth (EABW) of 9.2 GHz. The broadband and strong absorption on electromagnetic wave is attributed to the synergistic effects of ferroelectric properties from Bi2Fe4O9 and spinel structure of Fe3O4, supported by strong dipole coupling, interfacial polarization, and high-spin states of Fe ions. The underlying mechanism is thoroughly discussed, and the results demonstrate superior performance compared to similar studies in the field.