Meta-composites: NiO supported 3D carbon networks structured by 1D building blocks towards tailorable negative permittivity

Abstract

Meta-composites have drawn significant attention due to their preferable applications in electronic devices and promising mass production-scale. Compared with metallic particles as common conductive units in metamaterials or meta-composites fabrication, one-dimensional (1D) carbonaceous building blocks [e.g. multi-walled carbon nanotubes (MWCNTs) or carbon fibers] could provide preferable alternations. In this paper, nickel-modified carbon fibers and MWCNTs were served as 1D building blocks to fabricate meta-composites. Negative permittivity behavior in meta-composites were investigated at radio-frequency region. Herein, two different types of negative permittivity (i.e. dipole-type and plasma-type) were observed and analyzed by Lorentz model and Drude model respectively. Different variation trends of alternative conductivity spectra were followed by Jonscher’s power law or Drude model, indicating conductive mechanism change from hopping conduction to metal-like conduction. Equivalent circuit analysis to impedance response of meta-composites manifested correspondence between inductive characteristic and negative permittivity. This work not only presents novel routes to meta-composites designations by 1D carbon building blocks, but also further clarifies negative permittivity generation mechanism, which will facilitate applications in impedance matching, electromagnetic shielding and multi-layer high-k capacitors etc.