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Department of Dielectrics

Institute of Physics of the Czech Academy of Sciences


group Dielectric and IR spectroscopy science Dielectric and IR spectroscopy group THz and pump-probe science THz science and technology group Photon and neutron scattering group Light and neutron scattering group Theory Theory and
simulations
group Solid materials science Solid-state materials science group Liquid crystal material science Liquid crystals

About us

Main activities of Department of Dielectrics cover experimental and theoretical investigations of high-permittivity insulators like liquid crystals, ferroelectrics, multiferroics, piezoelectrics, semiconductor nanostructures, and low-loss materials.

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Photo of people of Dielectrics
Our mission: Understanding the materials for which the frequency dependence of dielectric function can be probed by capacitance, waveguide or optical techniques. Experimental research in the Department of Dielectrics is mostly based on dielectric, infrared, time-domain THz, Raman and neutron spectroscopy, but also calorimetry, nonlinear optics and scanning probe microscopy measurements. The information on the core research activities organized within our six principal research groups can be accessed through the following links:

The most significant fresh scientific results of our deparment are listed in the section Highlights.

News & Public

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16.04.2021 Research

Subterahertz collective dynamics of polar vortices

An artist take on the 'whirling' vibrational mode revealed in the polar vortex structure of PbTiO3/SrTiO3 superlattices [Nature 592, 376 (2021)] to highlight the front cover of the April issue of Nature.

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18.02.2021 Research

Perovskites and other Framework Structure Materials

E. Buixaderas in collaboration with Prof. J. Dec contributed with the chapter: “Phonons and relaxations in unfilled tetragonal tungsten-bronzes” to a new book titled "Perovskites and other Framework Structure Materials: new trends and perspectives", published by Collaborating Academics IP, France.

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04.02.2021 Research

Special Issue on the Contributions of Women in Ferroelectrics Research

Impressive schematic of the crystal structure of the tetragonal tungsten-bronze family made by Elena Buixaderas has been selected for the front cover in the IEEE TUFFC Special Issue on the Contributions of Women in Ferroelectrics Research and Development.

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05.01.2021 Research

From superlattices to supercrystals

Researchers from Department of Dielectrics, in a world-wide collaboration led by Dr. Pavlo Zubko from University College London, have found that in superlattices, composed of layers of a ferroelectric material separated by thin metallic spacers, electric dipoles form an unusual pattern of nanoscale domains that order in three dimensions to create a ‘domain supercrystal’, exhibiting outstanding dielectric response.

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03.12.2020 Media

Researchers' Night in the THz lab

Petr Kužel and his colleagues from the THz science and technology group introduced their research themes in a  general public video during the European Researchers' Night.

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02.12.2020 Award

Online art opening of the FZU Photo Competition 2020

Within European Researchers' Night on 27. November 2020 an online art opening of the FZU Photo Competition was performed. Alexey Bubnov got the 2nd place for his image of a beautiful liquid crystal texture resembling the Sun’s corona.

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Latest Highlights
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New material for 5G mobile networks

Epitaxial strained thin films of (SrTiO3)n-1(BaTiO3)1SrO were found to be a promising new material for mobile network of the 5th generation [Nature Mater. 19, 176 (2020)].

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Ferroelectric phase transition in water molecules localized in mineral cordierite

We discovered that hydrogen bonds are eliminated and the Coulombic interactions dominate in water molecules localized in nano-channels of mineral cordierite. Their dipole moment is perpendicular to the channel axis c and our dielectric spectroscopy study have revealed their ordering at ~3 K. The critical relaxation tending to this ordering is polarized along the a-axis direction and lies in the radiofrequency range. Spontaneous polarization measurements yield the saturated value of ~3 nC/cm2 at 0.3 K [Nat. Commun. 11, 3927 (2020)].

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Making EuO multiferroic by epitaxial strain engineering

Optical soft mode driven ferroelectric phase transition was discovered in IR spectra of tensile strained ferromagnetic EuO thin films [Commun. Mater. 1, 74 (2020)].

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Seemingly anisotropic magnetodielectric effect in isotropic EuTiO3 ceramics

Anisotropic magnetodielectric effect was observed at 0.3 K in the low-frequency dielectric spectra of antiferromagnetic EuTiO3 ceramics [Phys. Rev. B 102, 144402 (2020)].

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Organic nanotubes created from mesogenic lactic acid derivatives

We found a facile route how to prepare nanotubes from rod-like mesogens dissolved in typical organic solvents. For selected types of chiral rod-like molecules, both enantiomers as well as the racemic mixtures, the nanotubes are formed by slow evaporation from a solution, regardless the solvent, concentration or deposition type. Obtained supramolecular assemblies were studied using various experimental techniques and nanotubes of 50-60 nm diameter described. We proposed rolling-up mechanism related to the surface tension difference at the opposite layer surfaces.

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Mesoscopic polarization dynamics and two ferroelectric sublattices in the uniaxial tetragonal tungsten bronze (SrxBa1−x)Nb2O6

The high-frequency dielectric behavior of uniaxial tungsten-bronze strontium barium niobate crystals with various Sr/Ba ratios have been studied in order to thoroughly understand the evolution of the relaxation dynamics across the ferroelectric phase transition. We showed that the dielectric response along the polar axis consists of three relaxations corresponding to polarization mechanisms related to several correlation lengths of mesoscopic order and that they are closly associated with two different ferroelectric subsystems.in the structure [1].

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Raman scattering yields cubic crystal grain orientation

The anisotropy of Raman scattering was applied to determine the orientation of individual microcrystal grains, as small as a few µm, of GaV4S8 polycrystalline compound. This was possible by measuring polarised Raman spectra as a function of rotation of the sample along the laser direction. On comparing the resulting set of spectra with a computer simulation for particular symmetries, the orientation of the crystal grains could of the determined with good precision.

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Latest Key Articles

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Q. Li, V.A. Stoica, M. Paściak, Y. Zhu, Y. Yuan, T. Yang, M.R. McCarter, S. Das, A.K. Yadav, S. Park, C. Dai, H.J. Lee, Y. Ahn, S.D. Marks, S. Yu, C. Kadlec, T. Sato, M.C. Hoffmann, M. Chollet, M.E. Kozina, S. Nelson, D. Zhu, D.A. Walko, A.M. Lindenberg, P.G. Evans, L.-Q. Chen, R. Ramesh, L.W. Martin, V. Gopalan, J.W. Freeland, J. Hlinka, and H. Wen

Subterahertz collective dynamics of polar vortices

Nature 592, 376 (2021).
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M. Hadjimichael, Y. Li, E. Zatterin, G. A. Chahine, M. Conroy, K. Moore, E. N. O’ Connell, P. Ondrejkovic, P. Marton, J. Hlinka, U. Bangert, S. Leake, and P. Zubko

Metal–ferroelectric supercrystals with periodically curved metallic layers

Nat. Mater. 20, 495 (2021).
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V. C. Paingad, J. Kunc, M. Rejhon, I. Rychetský, I. Mohelský, M. Orlita, and P. Kužel

Ultrafast plasmon thermalization in epitaxial graphene probed by time-resolved THz spectroscopy

Adv. Funct. Mater. 31, 2105763 (2021).
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L.N. Alyabyeva, A.S. Prokhorov, D.A. Vinnik, V.B. Anzin, A.G. Ahmed, A. Mikheykin, P. Bednyakov, C. Kadlec, F. Kadlec, E. de Prado, J. Prokleška, P. Proschek, S. Kamba, A.V. Pronin, M. Dressel, V.A. Abalmasov, V.V. Dremov, S. Schmid, M. Savinov, P. Lunkenheimer, and B.P. Gorshunov

Lead-substituted barium hexaferrite for tunable terahertz optoelectronics

NPG Asia Mater. 13, 63 (2021).
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N. Podoliak, M. Cigl, V. Hamplová, D. Pociecha, and V. Novotná

Multichiral liquid crystals based on terphenyl core laterally substituted by chlorine atom

J. Mol. Liq. 336, 116267 (2021).
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E. Dmochowska, J. Herman, M. Czerwiński, S. Stulov, A. Bubnov, and P. Kula

Self-assembling behaviour of chiral calamitic monoacrylates targeted for polymer stabilisation of polar smectic phases in chiral liquid crystals

J. Mol. Liq. 331, 115723 (2021).
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I. Jankowska-Sumara, M. Paściak, M. Podgórna, A. Majchrowski, M. Kopecký, and J. Kub

Incommensurately modulated structures in Pb(Zr1−xSnx)O3 single crystals by x-ray diffraction

APL Materials 9, 021101 (2021).
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V.Novotná, L. Lejček, V. Hamplová, and J. Vejpravová

Defect structures of magnetic nanoparticles in smectic a liquid crystals.

Molecules 26, 5717 (2021).

Last update: 8 October 2021 (admin)