Enhanced electromagnetic interference shielding with low reflection induced by heterogeneous double-layer structure in BiFeO3/BaFe7(MnTi)2.5O19 composite

High-performance electromagnetic interference (EMI) shielding with low reflection is still a technical challenge for EMI shielding materials to reduce secondary pollution of electromagnetic wave irradiation. Here, we design a heterogeneous double-layer structure based on semiconductors BiFeO3 and BaFe7(MnTi)2.5O19 (BFO and BFMTO), which effectively decreases the reflection and greatly enhances EMI shielding effectiveness simultaneously. The absorption attenuation contribution of EMI power is close to 90%, and the shielding effectiveness exceed 10 dB in entire X-band, which is 150% of that of the homogeneous mixed structure. The experimental results demonstrate that the reduction of reflection is attributed to the decrease of the electrical conduction due to the formation of Schottky potential barriers in the interface between BFO and BFMTO. More importantly, the positive-negative charge pairs in the interface induce interfacial polarization which can interact with electromagnetic wave and thus cause strong attenuation. This work opens up a promising feasible route for the development of low-reflection and strong-absorption EMI shielding materials.