Low-frequency relaxation modes in ferroelectric liquid crystal/gold nanoparticle dispersion: impact of nanoparticle shape |
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| Authors: | F. V. Podgornov R. Wipf B. Stühn A. V. Ryzhkova W. Haase |
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| Affiliation: | 1. Eduard-Zintl-Institute for Inorganic and Physical Chemistry, Darmstadt University of Technology, Darmstadt, Germany;2. Electrical Engineering Technologies Laboratory, Department of Physics, South Ural State University, Chelyabinsk, Russiafedorpod@yahoo.de;4. Institute for Solid State Physics, Darmstadt University of Technology, Darmstadt, Germany;5. Electrical Engineering Technologies Laboratory, Department of Physics, South Ural State University, Chelyabinsk, Russia |
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| Abstract: | Low-frequency (1 mHz–100 Hz) dielectric relaxation modes were experimentally studied in ferroelectric liquid crystal (FLC)/gold nanoparticles (nanospheres and nanorods) dispersion. It was demonstrated that the dielectric spectra of nanodispersion are strongly influenced by the shape of nanoparticles. Using different formalisms of the impedance spectroscopy, three possible low-frequency relaxation processes were found in the dispersions and the pure FLC. Due to the electrical double layers (EDLs) near nanoparticles and the alignment layers, one can observe the relaxation of the EDL polarisation around the nanoparticles (Schwarz’s relaxation) and near the driving indium tin oxide (ITO) electrodes (electrode polarisation). The other possible relaxation process is interfacial polarisation (Maxwell–Wagner mode) in which the frequency is unaffected by the nanoparticles. It was shown that Schwarz’s relaxation frequency strongly depended on the shape and size of the nanoparticles. Moreover, dispersion of nanoparticles significantly reduced direct current conductivity of the FLC mixture. |
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| Keywords: | Ferroelectric liquid crystals gold nanoparticles relaxation modes dielectric spectroscopy electric double layers |
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