Abstract

Ferromagnetic-dielectric nanocomposites have attracted extensive interests for its high electromagnetic wave absorption (EMA) performance due to the synergetic effects between different components. Herein, we report the design of core–shell structured Co₇Fe₃@TiO₂ composite particles, which are subsequently annealed in H₂/Ar atmosphere to further improve its EMA performance. The introducing of TiO₂ dielectric shell together with hydrogen annealing contributes greatly to the electromagnetic properties due to the increased conductivity and enhanced ferromagnetic resonance. Excellent EMA performance is achieved in S (2–4 GHz) and C (4–8 GHz) bands in coatings using Co₇Fe₃@TiO₂ as absorbents. Apart from the high EMA efficiency, the location of EMA band can be tailored in a wide range through regulating the coating thickness. Specifically, an effective absorption band of 2.0 GHz in C band at a thickness of 2.62 mm, and an effective absorption band of 1.7 GHz are achieved in S band at thicknesses of 4.0–5.0 mm. The excellent electromagnetic properties are ascribed to the effective complementary between dielectric loss and ferromagnetic loss.

Graphic Abstract

中文翻译：

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设计用于S和C波段电磁波吸收的Co 7 Fe 3 @TiO 2核壳纳米球

摘要

由于不同组分之间的协同作用，铁磁介电纳米复合材料因其高电磁波吸收（EMA）性能而引起了广泛的关注。在此，我们报告了核壳结构的Co ₇ Fe ₃ @TiO ₂复合颗粒的设计，随后将其在H ₂ / Ar气氛中进行退火，以进一步改善其EMA性能。TiO ₂介电壳的引入与氢退火一起，由于增加的电导率和增强的铁磁共振，极大地有助于电磁性能。使用Co ₇ Fe _3的涂层在S（2-4 GHz）和C（4-8 GHz）波段中均具有出色的EMA性能。@TiO ₂作为吸收剂。除了具有较高的EMA效率外，还可通过调节涂层厚度在很大范围内调整EMA带的位置。具体而言，在厚度为2.62 mm的C波段中，有效吸收带为2.0 GHz，在厚度为4.0-5.0 mm的S波段中，获得1.7 GHz的有效吸收带。优异的电磁性能归因于介电损耗和铁磁损耗之间的有效互补。

图形摘要