Low-temperature sintering Graphene/CaCu3Ti4O12 nanocomposites with tunable negative permittivity
Low-temperature sintering Graphene/CaCu3Ti4O12 nanocomposites with tunable negative permittivity
复制标题
低温烧结负介电常数可调的石墨烯/CaCu3Ti4O12纳米复合材料
DOI：
10.1016/j.jallcom.2018.09.049
复制
发表时间：
2019-01-15
影响因子：
6.2
通讯作者：
Fan, Runhua
中科院分区：
文献类型：
--
作者：
Qu, Yunpeng;Du, Yu;Fan, Runhua
由于超材料中存在负介电常数，如何有效地调节负介电常数仍然是满足实际应用的挑战。超复合材料可以提供可调负介电常数的替代途径。本文通过低温常压烧结制备了不同GR含量的石墨烯/CaCu3Ti4O12（GR/CCTO）超复合材料。详细研究了 GR/CCTO 的微观结构和成分。分别在 10 kHz - 1 MHz 和 20 MHz - 1 GHz 区域研究了 GR/CCTO 纳米复合材料的电学和介电性能。交流电导率谱呈现出不同的变化趋势，可以用 Jonscher 幂律或 Drude 模型来解释，表明导电机制从跳跃传导向类金属传导转变。在射频区域观察到洛伦兹型和/或德鲁德型负介电常数行为。通过改变GR/CCTO纳米复合材料中的GR含量实现了可调的负介电常数。 GR/CCTO复合材料阻抗响应的等效电路分析表明了电感特性与负介电常数之间的对应关系。这项工作不仅提出了调节负介电常数的新途径，而且进一步阐明了负介电常数的产生机制，这将极大地促进在阻抗匹配、电磁屏蔽和多层高k电容器等方面的应用。(C) 2018 Elsevier B.V.保留所有权利。
Since negative permittivity demonstrated in metamaterials, how to effectively tune negative permittivity still the challenge to satisfy practical applications. Meta-composites could provide alternative routes to tunable negative permittivity. In this paper, Graphene/CaCu3Ti4O12 (GR/CCTO) meta-composites with different GR content were fabricated by low-temperature pressureless sintering. Microstructures and compositions of GR/CCTO were investigated in detail. The electrical and dielectric properties of GR/CCTO nanocomposites were investigated at 10 kHz - 1 MHz and 20 MHz - 1 GHz region respectively. AC conductivity spectra showed different variation trends which were explained by Jonscher's power law or Drude model, indicating conductive mechanism transformation from hopping conduction to metal-like conduction. Lorentz-type and/or Drude-type negative permittivity behaviors were observed at radio-frequency region. Tunable negative permittivity were realized by changing GR content in GR/CCTO nanocomposites. Correspondence between inductive characteristic and negative permittivity was manifested by equivalent circuit analysis of impedance response of GR/CCTO composites. This work not only presents novel routes to tune negative permittivity, but also further clarifies negative permittivity generation mechanism, which will greatly facilitate applications in impedance matching, electromagnetic shielding and multi-layer high-k capacitors etc. (C) 2018 Elsevier B.V. All rights reserved.