High-Frequency Negative Permittivity from Fe/Al2O3 Composites with High Metal Contents

Authors

  • Meng Gao,

    1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • Zhi-cheng Shi,

    1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • Run-hua Fan,

    Corresponding author
    • Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • Lei Qian,

    Corresponding author
    • Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • Zi-dong Zhang,

    1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • Jing-yan Guo

    1. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan, China
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  • This work was supported by National Natural Science Foundation of China (Grant Nos. 50772061, 51172131), Program for New Century Excellent Talents in University (Grant No. NCET-10-518), and Independent Innovation Foundation of Shandong University (IIFSDU-2010JQ002, GIIFSDUYYX10011).

Authors to whom correspondence should be addressed. e-mails: fan@sdu.edu.cn; qleric@sdu.edu.cn

Abstract

For conventional metal/ceramic composites, we report an interesting negative permittivity behavior, which was usually observed in artificial metamaterials. The Fe/Al2O3 composites with different Fe volume contents ranging from 10% to 40% were prepared through hot-pressing sintering. The impedance and dielectric properties of the composites in high frequency range present a distinct dependence on the composition, and the negative permittivity is obtained when Fe content exceeds 20 vol%. The experimental results of negative permittivity from the composites above percolation threshold are in good agreement with fitting results from Drude model. The tunability of negative permittivity makes Fe/Al2O3 composites promising candidates for the double negative materials.

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