Affiliation:
1. College of Ocean Science and Engineering Shanghai Maritime University Shanghai 201306 P. R. China
2. Department of Orthopaedics and Traumatology The University of Hong Kong Pokfulam Hong Kong 999077 P. R. China
3. Department of Applied Mathematics The Hong Kong Polytechnic University Hong Kong 999077 P. R. China
4. Department of Materials Faculty of Science and Engineering The University of Manchester Manchester M13 9PL UK
5. Key Laboratory for Liquid‐Solid Structural Evolution and Processing of Materials (Ministry of Education) Shandong University 17923 Jingshi Road Jinan 250061 P. R. China
6. Institute of Photonic Chips University of Shanghai for Science and Technology Shanghai 200093 P. R. China
Abstract
AbstractEpsilon‐near‐zero (ENZ) materials, exhibiting unique physical characteristics such as near‐zero refraction, have aroused extensive interest and exhibit great potentials in novel applications of perfect absorbers, high‐harmonic generation, and nonlinear optical response. Here, for the first time, magnetic‐driven broadband ENZ materials are designed by fabricating polyvinyl alcohol (PVA)/Ni@carbon nanotubes (CNTs) films. Dielectric properties including real permittivity (ɛ′), imaginary permittivity (ɛ″), dielectric loss (tanδ), and impedance (Z) are investigated. When Ni@CNTs content reached 30 wt.%, negative permittivity transferred to positive permittivity at ≈11.5 MHz, and epsilon‐near‐zero (|ɛ′| < 1) is realized from ≈9 to 14 MHz, exhibiting broad ENZ bandwidth of ≈5 MHz. Theory calculations confirm that delocalized electrons are introduced from CNTs, which improve the carrier mobility and achieve low frequency dispersion behavior. Longer interfacial polarization electric fields between PVA and CNTs are also demonstrated by theory calculations, enhancing the positive permittivity response to offset negative permittivity response from Ni@CNTs. These two mechanisms result in broadband ENZ at radio frequency. This film also exhibits excellent magnetic actuation ability under magnetic field, broadening applications from ENZ materials to novel fields such as magnetically actuated robots with perfect absorption, magnetic‐driven biomimetic aircrafts with shielding ability, magnetic‐driven photodetectors, etc.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Shanghai Municipality
China Association for Science and Technology
Subject
Electrochemistry,Condensed Matter Physics,Biomaterials,Electronic, Optical and Magnetic Materials
Cited by
4 articles.
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