Percolative cobalt/silicon nitride composites with tunable negative electromagnetic parameters
Percolative cobalt/silicon nitride composites with tunable negative electromagnetic parameters
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DOI：
10.1039/c6ra15529d
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发表时间：
2016-08
期刊：
影响因子：
3.9
通讯作者：
Zidong Zhang;Chuanbing Cheng;Xu Han
中科院分区：
文献类型：
--
作者：
Zidong Zhang;Chuanbing Cheng;Xu Han
本文研究了用煅烧-煅烧法制备的Co/Si_3N_4复合材料的微观结构与电磁性能的关系。钴粒子的互连性增强导致了逾渗现象的出现，导电机制由跳跃导电转变为类金属导电。在逾渗阈值以上的复合材料表现出负介电常数和负磁导率行为，这分别归因于自由电子的等离子体振荡和导电钴网络的抗磁响应。这种负电磁参数的频率范围和大小与钴含量密切相关。当钴含量达到35wt%时，在550 MHz至1 GHz的频率范围内同时实现了负介电常数和负磁导率。Co/Si_3N_4复合材料的成分和微观结构定制的实验探索对开发负电磁参数可调材料具有重要意义。
In this paper, the relationship between the microstructures and electromagnetic properties of cobalt/silicon nitride (Co/Si3N4) composites synthesized by an impregnation–calcination process are discussed. The enhanced interconnectivity of cobalt particles led to the appearance of percolation phenomenon and the change of conductive mechanism from hopping conduction to metal-like conduction. The composites above percolation threshold exhibited the negative permittivity and negative permeability behavior, which were mainly ascribed to the plasma oscillation of free electrons and the diamagnetic responses of conductive cobalt network, respectively. The frequency region and magnitude of such negative electromagnetic parameters closely associated with the cobalt content. When the cobalt content reached 35 wt%, simultaneous negative permittivity and negative permeability were realized in the frequency range from 550 MHz to 1 GHz. The experimental exploration of Co/Si3N4 composites by tailoring compositions and microstructures has great significance on the development of tunable negative electromagnetic parameter materials.