Low-frequency plasmonic state and tunable negative permittivity in percolative graphite / barium titanate composites. Issue 1 (1st January 2022)

• Record Type: Journal Article
• Authors: Song, X.T.; Shi, Guangyue; Fan, Guohua; Liu, Yao; Fan, Runhua
• Is Part Of: Ceramics international. Volume 48:Issue 1(2022)
• Page Start: 832
• Page End: 836
• Publication Date: 2022-01-01
• Subjects: Dielectric behavior -- Negative permittivity -- Percolation -- Composite; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.09.164
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Percolative composites with negative permittivity have attracted widespread attentions due to their great potential in electromagnetic shielding and microwave devices. Targeting at achieving epsilon-negative properties, the percolative graphite/barium titanate (GR/BaTiO3 ) composite is herein designed and prepared using hot-pressing sintered process. It's found that the plasma oscillations of delocalized electrons result in the epsilon negative permittivity behaviors when the GR contents exceeds the 2 wt% (percolation threshold), and frequency dependence of the negative permittivity which is in well agreement with the Drude model. Meanwhile, it's demonstrated that the ac conductivity represents a typical metal-like behavior as the conductive networks formed within the composites by the increasing GR loadings. Moreover, the equivalent circuit analysis reveals the relationships between capacitive-inductive transition and the conversion of permittivity changing from positive to negative. This work provides effective possibility for developing excellent dielectric properties of percolative GR/BaTiO3 composite for capacitors and coil-less electrical inductors applications.