Enhancing broadband electromagnetic wave absorption performance of NZFO/BSTO multiferroic materials in the X and K_u...

Multiferroic composites with the composition xNi_0.5Zn_0.5Fe₂O₄/(1 - x)(Ba_0.8Sr_0.2TiO₃) (denoted as NZFO/BSTO) (where x = 0, 0.1, 0.2, 0.3, 0.4, and 1.0) were fabricated using a solid-state reaction method combined with spark plasma sintering. The obtained materials exhibited an average particle size of approximately 500 nm. X-ray diffraction analysis confirms the co-existence of the ferromagnetic Ni_0.5Zn_0.5Fe₂O₄ (NZFO) phase and the ferroelectric Ba_0.8Sr_0.2TiO₃ (BSTO) phase. As the NZFO content increases from x = 0.1 to 0.4, the saturation magnetization (M _s) rises from 13.6 to 56.9 emu g^-1, while the remanent magnetization (M _r) increases from 0.71 to 1.88 emu g^-1. Simultaneously, the P-E hysteresis loops become more pronounced, with a significant increase in both the maximum polarization (P _m) and remanent polarization (P _r). The coercive electric field (E _c) also increases markedly from 1.94 kV cm^-1 to 3.56 kV cm^-1 under an applied electric field of 12.5 kV cm^-1. The composite with the ferromagnetic phase fraction x = 0.4 exhibits excellent broadband electromagnetic wave absorption performance. At thicknesses of 2.0 mm and 2.5 mm, the effective absorption bandwidth exceeds 5.4 GHz and 5.7 GHz, respectively. Notably, minimum reflection loss (RL_min) values of -48.3 dB and -43.9 dB are achieved at 15.7 GHz and 12.6 GHz, respectively. These results demonstrate the strong potential of the material for practical applications in electromagnetic wave absorption in the X-band and K_u-band frequency ranges, particularly in radar stealth and military technologies.