Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

How to Enhance Sensitivity of Liquid Crystals to External Magnetic Field?

100%
Kopčanský P., Tomašovičová N., Gdovinová V., Timko M., Éber N., Tóth-Katona T., Jadzyn J., Honkonen J., Chaud X.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 2
157-162
EN
Liquid crystals, due to their large dielectric anisotropy, respond very sensitively to application of an external electric field, whereas they are only weakly sensitive to the magnetic field. A possible way of improving that sensitivity is doping liquid crystals with magnetic nanoparticles. As a result, stable colloidal suspensions of liquid crystals with relatively low concentrations of magnetic nanoparticles (called ferronematics, ferrocholesterics, ferrosmectics, etc.) can be produced. We illustrate some examples of the influence of the magnetic field, as well as of a superposition of magnetic and electric fields on the structural transitions (e.g. on the Fréedericksz transition) in ferronematics based on the calamitic liquid crystal 4-(trans-4'-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT). It is shown that the samples respond to the applied magnetic field of low strength. The effects of the magnetic particles and magnetic field on the nematic to isotropic phase transition temperature are discussed as well.
2
Content available remote

Low Magnetic Field Response in Ferronematics

100%
Gdovinová V., Tomašovičová N., Závišová V., Éber N., Tóth-Katona T., Royer F., Jamon D., Jadzyn J., Kopčanský P.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
934-936
EN
In this work the 4-n-hexyl-4'-cyanobiphenyl liquid crystal was doped with differently shaped magnetite nanoparticles. The structural changes were observed by capacitance measurements. Influence of the shape of magnetic particles on magnetic Fréedericksz transition depends on the type of anchoring, which is characterized by the density of the anchoring energy and by the initial orientation between the liquid crystal molecules and the magnetic moment of the magnetic particles. It was observed that in the case of doping with spherical particles, the critical magnetic field is shifted to higher values with increase of volume concentration of the magnetic nanoparticles but decreases with increase of biasing voltage. In the case of doping with rod-like particles, the critical magnetic field is almost independent of the volume concentration of the magnetic nanoparticles.
3
Content available remote

The Anchoring Energy of Liquid Crystal Molecules to Magnetic Particles in HAB-Based Ferronematics

100%
Tomašovičová N., Koneracká M., Kopčanský P., Timko M., Závišová V., Vajda A., Fodor-Csorba K., Éber N., Tóth-Katona T., Jadzyn J.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 1
591-594
EN
In this work we describe the magnetic Freedericksz transition in HAB-based (4, 4'-di-n-heptylazoxybenzene) ferronematics. The ferronematic samples were prepared with two different volume concentrations of magnetic particles φ_1 = 2×10^{-5} and φ_2 = 2×10^{-4}. The liquid crystal HAB is nematic at the temperatures from ≈53°C to 70°C and smectic A at the temperatures under 53°C. The anisotropy of dielectric permitivity of HAB liquid crystal is positive in nematic phase and negative in smectic A phase. The magnetic Fredericksz transition was studied in nematic phase at temperature 60°C.
4
Content available remote

Structural Phase Transition in Liquid Crystal Doped with Gold Nanoparticles

81%
Kopčanský P., Tomašovičová N., Koneracká M., Timko M., Mitróová Z., Závišová V., Éber N., Fodor-Csorba K., Tóth-Katona T., Vajda A., Jadzyn J., Beaugnon E., Chaud X.
|
|
issue 5
988-989
EN
The influence of the inclusion of the dodecanethiol functionalized gold particles (with diameter 3-5 nm) on the structural transitions was investigated. The studied samples were based on the nematic liquid crystal 4-(trans-4'-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT). The volume concentration of the gold particles was ϕ_1 = 2 × 10^{-4} and ϕ_2 = 10^{-3}. The obtained results showed that the inclusion of the gold particles in the 6CHBT liquid crystal increases the sensitivity of such system on the external magnetic field.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.