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 Bi 2 Fe 4 O 9 /Fe 3 O 4 nanoflower to enhance electromagnetic wave absorption. Bi 2 Fe 4 O 9 , synthesized via a hydrothermal method, was composited with different content Fe 3 O 4 nanocrystals. The strong binding between sheets of nanoflowers provides large surface area and active sites for electromagnetic wave absorption (EMA). The combination of Bi 2 Fe 4 O 9 and Fe 3 O 4 markedly enhanced the dielectric and magnetic properties, resulting in exceptional EMA performance. The sample achieved a minimum reflection loss (RL min ) 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 Bi 2 Fe 4 O 9 and spinel structure of Fe 3 O 4 , 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.