Meta-composites with negative permittivity are promising candidates for future electronics such as microwave absorbers, novel capacitors, etc. In this work, we proposed to develop the Fe/BaTiO3 meta-composites with tuneable negative permittivity. Fe content influenced the conductivity of composites and even led to the change of the conductive mechanism. The tuneable permittivity behavior was achieved by controlling the Fe fraction, and the plasma oscillation theory was employed to explain the negative permittivity behavior. Meanwhile, a frequency-switched negative permittivity was observed in this composite, which could be used to extend applications of meta-composites.

中文翻译：

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Fe/BaTiO3 元复合材料中可定制的负介电常数

具有负介电常数的元复合材料是未来电子产品的有希望的候选材料，例如微波吸收器、新型电容器等。在这项工作中，我们建议开发 Fe/BaTiO3具有可调负介电常数的元复合材料。Fe含量影响复合材料的导电性，甚至导致导电机理的改变。通过控制Fe比例来实现可调介电常数行为，并采用等离子体振荡理论来解释负介电常数行为。同时，在该复合材料中观察到频率切换的负介电常数，可用于扩展元复合材料的应用。