Enhanced Microwave Absorption Property of Ferroferric Oxide: the Role of Magnetoelectric Resonance
Enhanced Microwave Absorption Property of Ferroferric Oxide: the Role of Magnetoelectric Resonance
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DOI：
10.1016/j.cej.2021.134455
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发表时间：
2022-01
影响因子：
15.1
通讯作者：
Kang Zhang;Xin Li;Yulong Li;Junwei Lv;Rui Qin-;Xu Wang;Xiangyang Liu;Yang Liu
中科院分区：
文献类型：
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作者：
Kang Zhang;Xin Li;Yulong Li;Junwei Lv;Rui Qin-;Xu Wang;Xiangyang Liu;Yang Liu
对铁氧体材料进行改性可以有效地改善其微波吸收性能。然而，改善其高频性能的尝试仍然有限，并且对于实际应用来说相当麻烦。在此，我们提出了一种简单的方法，有效地提高了MA行为的Fe 3 O 4通过直接使用F2/N2气体的退火。具体地说，我们通过仔细控制F2浓度和煅烧温度，制备了具有氟掺杂的壳和未改性的Fe 3 O 4核的核-壳结构的氟化Fe 3 O 4（F-Fe 3 O 4）。我们发现了一个独特的“磁电协同共振”（MDR）的F-Fe 3 O 4的效果，表现为在14.8和16.6 GHz的双介电和磁共振峰的共同出现。带隙测量和分子模拟结果表明，氟掺杂导致的较小能隙有利于混合价态Fe 2 +/Fe 3+之间的电子跳跃和核壳界面处的电子聚集，从而引起同时发生的磁交换作用和Maxwell-Wagner效应（界面极化）.结果，入射电磁波可以通过磁交换谐振耦合介电谐振耗散，从而改善在MDR相同频率下的MA特性。与纯Fe 3 O 4相比，F-Fe 3 O 4的最小反射损耗提高了4倍，达到−64.9 dB，有效吸收带宽为5.03 GHz，几乎提高了1.6倍。我们相信这种简单有效的改性方法和MDR独特的损耗机制将推动高性能MA材料的结构设计。
The modification of ferrites can effectively improve their microwave absorption (MA) properties. However, attempts to improve their high-frequency performance were still limited and considerably cumbersome for practical application. Herein, we present a facile method that effectively improves the MA behavior of Fe3O4through direct fluorination using F2/N2gas. Specifically, we fabricated core–shell structured fluorinated Fe3O4(F-Fe3O4) with a fluorine-doped shell and an unmodified Fe3O4core by carefully controlling the F2concentration and fluorination temperature. We found a unique ‘magnetoelectric collaborative resonance’ (MDR) effect in F-Fe3O4, manifested by the co-occurrence of double dielectric and magnetic resonance peaks at 14.8 and 16.6 GHz. Band gap measurements and molecular simulations results indicated that the smaller energy gap derived from fluorine doping facilitates both electron hopping between the mixed-valence Fe2+/Fe3+states and electron accumulation at the core–shell interface, which induce simultaneous magnetic exchange interactions and the Maxwell–Wagner effect (interface polarization). As a result, the incident electromagnetic wave can be dissipated via magnetic exchange resonance coupled with dielectric resonance, thereby improving the MA properties at the same frequency of MDR. Compared with those of pristine Fe3O4, the minimum reflection loss of F-Fe3O4was four times higher, reaching −64.9 dB, and the effective absorption bandwidth was 5.03 GHz, which is almost 1.6 times higher. We believe this facile and effective modification method and the unique loss mechanism of MDR will advance the structural design of high-performance MA materials.