Abstract Magnetic/dielectric composites can offer good electromagnetic impendence. However, the strategy for embodying strong absorbing ability and broad effective absorption band simultaneously is a significant challenge. Therefore, assembled porous Fe3O4@g-C3N4 hybrid nanocomposites have been designed and synthesized, in which porous Fe3O4 nanospheres assembled by ~ 3 nm Fe3O4 nanoparticles are surrounded by g-C3N4. The introduction of g-C3N4 improves dielectric loss ability at 2–18 GHz and magnetic loss ability at 2–10 GHz, and enhances attenuation constant, and increases electromagnetic impedance degree. These merits ensure that assembled porous Fe 3 O4/g-C3N4 hybrid nanocomposites deliver superior microwave absorption performance, such as effective absorption bandwidth, fE, (reflection loss less − 10 dB) exceeding 5 GHz at 2.0–2.3 mm, the maximal fE of 5.76 GHz and minimal reflection loss of at least − 20 dB with thickness ranging from 2.3 to 10.0 mm, avoiding the sensitivity of absorption properties to absorbing layer thickness. Stable microwave absorbing performance originates from multi-interfacial polarization, multi-reflection, enhanced electromagnetic loss capability, and good electromagnetic impedance. Our study offers a new idea for stable microwave absorber at 2–18 GHz.

中文翻译：

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组装多孔 Fe 3 O 4 @gC 3 N 4 杂化纳米复合材料，具有多界面极化以实现稳定的微波吸收

摘要 磁性/介电复合材料具有良好的电磁阻抗。然而，同时体现强吸收能力和宽有效吸收带的策略是一个重大挑战。因此，已经设计并合成了组装的多孔 Fe3O4@g-C3N4 杂化纳米复合材料，其中由 ~ 3 nm Fe3O4 纳米粒子组装的多孔 Fe3O4 纳米球被 g-C3N4 包围。g-C3N4的引入提高了2-18GHz的介电损耗能力和2-10GHz的磁损耗能力，提高了衰减常数，增加了电磁阻抗度。这些优点确保组装的多孔 Fe 3 O4/g-C3N4 混合纳米复合材料具有卓越的微波吸收性能，例如有效吸收带宽 fE（反射损耗小于 - 10 dB）在 2.0-2.3 mm 时超过 5 GHz，5.76 GHz 的最大 fE 和至少 - 20 dB 的最小反射损耗，厚度范围为 2.3 至 10.0 mm，避免吸收特性对吸收层厚度的敏感性。稳定的微波吸收性能源于多界面极化、多反射、增强的电磁损耗能力和良好的电磁阻抗。我们的研究为稳定的 2-18 GHz 微波吸收器提供了新思路。