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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
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.

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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21.10.2019 Award

Vladimira Novotna was awarded the 2nd place in Photogenic Science Completion 2019

Photos of liquid crystals under a polarized microscope brought the second place to Vladimira Novotna in the category of ‘Photogenic Science’. The competition is organized by the Czech Academy of Sciences and by the association Science is Alive! (Věda žije! in Czech) and its aim is to evaluate photos related to science.

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TOPO2019 organized by Department of Dielectrics and by Czech Physical Society

The 5th International Workshop on Topological Structures in Ferroic Materials (TOPO2019) took place in Průhonice and Prague on June 16–20. The conference was organized by the Czech Physical Society and by the Department of Dielectrics of FZU with Jiří Hlinka being the conference chair.

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Upcoming Seminars & Workshops
26.11.2019 10:00, Na Slovance 2, room 117
Build a Bound State – Coupling Quantum Dots to Superconductors
Gorm Olle Steffensen
Niels Bohr Institute, Copenhagen
(show abstract)
10.12.2019 10:00, Na Slovance 2, room 117
Vortex ratchet effects in superconducting curved bridge
Bei Yi Zhu
National Lab for Superconductivity, Institute of Physics, Chinese Academy of Sciences, Beijing, China
(show abstract)
Latest Highlights
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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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Changes in spin and lattice dynamics induced by magnetic and structural phase transitions in multiferroic SrMn7O12

Upon cooling, SrMn7O12 undergoes a series of structural and magnetic phase transitions from cubic to rhombohedral symmetry, and to an incommensurately modulated crystal structure, which is connected with charge and orbital ordering of the Mn cations. We report IR, THz, and Raman spectra of SrMn7O12 ceramics reflecting corresponding changes in the phonon selection rules, including new phonons appearing in spin-order-induced ferroelectric phases [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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Soft mode driven local ferroelectric transition in lead-based relaxors

Analysis of IR and THz spectra using Bruggeman effective medium approach revealed that the mesoscopic structure of Pb(Mg1/3Nb2/3)O3 and Pb(Mg1/3Ta2/3)O3 consists of dynamic randomly oriented uniaxially anisotropic polar nanoregions with harder transverse optical polar modes in the direction along the local dipoles [1,2].

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Degenerate (identity) chemical reactions in ferro­elastic crystals

The work points to reconsideration of degenerate chemical reactions because of the chemical reactions which take place in a solid phase where the orientation of the substituting molecules is maintained. The work points to the examples of a ferroelastic switching which is accompanied by braking and reestablisment of chemical bonds. The article suggests that the definition of the degenerate chemical reactions might distinguish the reactions where the truly identical molecules are formed from those ones where the resulting molecules are enantiomers or enatiomorphs in case of domains.

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Latest Key Articles

J. Hlinka,

Doubling up piezoelectric performance

Science 364, 228 (2019).
X. Su, X. Zeng, H. Němec, X. Zou, W. Zhang, M. T. Borgström, and A. Yartsev,

Effect of hydrogen chloride etching on carrier recombination processes of indium phosphide nanowires

Nanoscale 11, 18550 (2019).
P. Kužel and H. Němec,

Terahertz Spectroscopy of Nanomaterials: a Close Look at Charge-Carrier Transport

Adv. Opt. Mater. 7, 1900623 (2019).
V. Novotná, V. Hamplová, L. Lejček, D. Pociecha, M. Cigl, L. Fekete, M. Glogarová, L. Bednárová, P. Majewski, and E. Gorecka,

Organic nanotubes created from mesogenic derivatives.

Nanoscale Adv. 1, 2835 (2019).
N. N. Kovaleva, D. Chvostova, Z. Potůček, H. D. Cho, X. Fu, L. Fekete, J. Pokorny, Z. Bryknar, K. I. Kugel, and A. Dejneka,

Efficient green emission from edge states in graphene perforated by nitrogen plasma treatment

2D Mater. 6, 045021 (2019).

Last update: 1 November 2019 (admin)