Synthesis and Microwave Absorption Properties of Novel Bi_1/2(Na_0.8K_0.2)_1/2TiO₃/Fe₃O₄ Composite

Abstract

The combination of two dielectric-magnetic components in the same composite has been shown to significantly improve the effectiveness of electromagnetic (EM) shielding and microwave absorption (MWA) because they have both a combination of high dielectric and magnetic losses and good impedance matching. The novel Bi_1/2(Na_0.8K_0.2)_1/2TiO₃/Fe₃O₄ (BNKT/Fe₃O₄) composite has been successfully synthesized by a two-step method with wide effective absorption bandwidth (EAB = 16 GHz) in the high-frequency (2–18 GHz). It was evident that the MWA efficiency of the BNKT/Fe₃O₄ composite has been significantly improved compared with pure Bi_1/2(Na_0.8K_0.2)_1/2TiO₃ or Fe₃O₄ materials. In addition, the BNKT/Fe₃O₄ composite could achieve reflection loss (RL = −39.41 dB, ∼99.99% at 10.16 GHz) with a sample thickness optimal (d = 4.7 mm). This work shows that the novel BNKT/Fe₃O₄ composite has excellent MWA properties, all contributing to a potential candidate in the electromagnetic wave absorption and shielding fields.

Fig. 5 The 3-D projection (magnitude) of scattering coefficients (S₁₁) and (S₂₁) of the BNKT/Fe₃O₄ composite with different thicknesses (2.9–5.4 mm) (a), (b); The relationship between reflection loss (dB) and the MWA percentage (%) (c); the RL (d) 2-D contour map (e) and 3-D reflection loss (f) of BNKT/Fe₃O₄ composite with different thicknesses (2.9–5.4 mm).