Showing papers by "Peter Kopčanský published in 2015"
TL;DR: In this article, the anisotropy of acoustic attenuation in transformer oil-based magnetic fluids upon the external magnetic field was studied to discover the structure of nanoparticles and the proportion of the acoustic wave energy used for excitation of the translational and rotational degrees of freedom was also established.
21 citations
TL;DR: In this paper, the external magnetic field was applied to external magnetic fields and the authors proposed a method to obtain the magnetic field parameters of the external magnetometer and the external Magnetic Field model.
Abstract: to External Magnetic Field? P. Kop£anský, N. Toma2ovi£ova, V. Gdovinova, M. Timko, N. Eber, T. Toth-Katona, J. Jadzyn, J. Honkonen and X. Chaud Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Kosice, Slovakia Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60179 Poznan, Poland Department of Physical Sciences, University of Helsinki, Gustav Hallstromin katu 2, Helsinki, Finland High Magnetic Field Laboratory, CNRS, 25 Avenue des Martyrs, Grenoble, France
9 citations
TL;DR: In this article, the influence of doping with spherical magnetic nanoparticles on the mixture of a bent core and a calamitic liquid crystal was investigated and a reduction of the critical field of the magnetic Freedericksz transition was found by more than a factor of two after the doping.
Abstract: We have investigated the influence of doping with spherical magnetic nanoparticles on the mixture of a bent-core and a calamitic liquid crystal Results showed a reduction of the critical field of the magnetic Freedericksz transition by more than a factor of two after the doping Moreover, we give for the first time experimental evidence of the theoretically predicted magnetically induced negative shift of the isotropic to nematic phase transition temperature
8 citations
TL;DR: In this paper, the structural changes in magnetic fluids with different nanoparticle diameter based on transformer oils TECHNOL and MOGUL under the effect of a magnetic field and temperature were studied by acoustic spectroscopy.
Abstract: Abstract The properties of magnetic fluids depend on the nanoparticle diameter, their concentration and the carrier liquid. The structural changes in magnetic fluids with different nanoparticle diameter based on transformer oils TECHNOL and MOGUL under the effect of a magnetic field and temperature were studied by acoustic spectroscopy. At a linear and jump changes of the magnetic field at various temperatures a continuous change was observed of acoustic attenuation caused by aggregation of the magnetic nanoparticles to structures. From the anisotropy of acoustic attenuation and using the Taketomi theory the basic parameters of the structures are calculated and the impact of nanoparticle diameters on the size of structures is confirmed.
8 citations
4 citations
TL;DR: Properties of magnetosome suspension under the inence of magnetic field A. Jozefczak, M. Mol£an, Z. Rozynek, T. Hornowski, A. Timko, J. Tothova, P. Kop£anský and B. Leszczyski.
Abstract: Properties of Magnetosome Suspension under the In uence of Magnetic Field A. Jozefczak, M. Mol£an, Z. Rozynek, T. Hornowski, A. Skumiel, M. Timko, J. Tothova, P. Kop£anský and B. Leszczy«ski Institute of Acoustics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Pozna«, Poland Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Ko2ice, Slovakia Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland Department of Physics, NTNU, Hogskoleringen 5, NO-7491 Trondheim, Norway Department of Physics, Technical University of Ko2ice, Park Komenskeho 2, 042 00 Ko2ice, Slovakia NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Pozna«, Poland
4 citations
TL;DR: Magnetic Nanoparticles A. Jurikova, K. Csach, J. Mi2kuf, N. Toma2ovi£ova, Z. Mitroova, V. Zavi2ova as discussed by the authors
Abstract: Magnetic Nanoparticles A. Jurikova, K. Csach, J. Mi2kuf, N. Toma2ovi£ova, Z. Mitroova, V. Zavi2ova, M. Koneracka, P. Kop£anský, M. Timko, N. Eber, K. Fodor-Csorba, A. Vajda Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Ko2ice, Slovakia Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, P. O. Box 49, Hungary
3 citations
TL;DR: In this paper, two low volume concentrations of spherical magnetic nanoparticles were added to liquid crystal during its isotropic phase to attenuate surface acoustic wave propagating along ferronematic liquid crystals (6CHBT).
2 citations
TL;DR: In this paper, the phase transitions of different binary mixtures of a bent-core (10DClPBBC) and a rod-shaped (6OO8) liquid crystal were studied using differential scanning calorimetry.
Abstract: Phase transitions of different binary mixtures of a bent-core (10DClPBBC) and a rod-shaped (6OO8) liquid crystal were studied using differential scanning calorimetry. For the binary mixture with 50:50 weight ratio of bent-core and rod-shaped molecules, the nematic to smectic transition occurred below the temperature of 40°C and crystallization was shifted to sub-ambient temperature. It was found that crystallization was the phase transition with the lowest apparent activation energy.
2 citations
TL;DR: In this paper, the behavior of BCMF in an external magnetic field was studied by acoustic spectroscopy and the linear increase, decrease and jump change of the external magnetic fields up to 200 mT was applied and corresponding changes of acoustic attenuation were studied.
1 citations
TL;DR: In this paper, the formation of nematic liquid crystal phase in solutions containing lysozyme amyloid brils and magnetic nanoparticles using oscilloscopic method was studied and the analysis of the obtained results suggests that the decrease in conductivity of solutions in presence of magnetic eld is due to decrease of the ion mobility caused by re-arrangement of structures in the solution.
Abstract: Dielectric Properties of Lyotropic Magnetic Liquid Crystal P. Kop£anský, L. Tom£o, J. Jadzyn, J. Swiergiel, J. Majoro2ova, M. Kubov£ikova, M. Timko, M. Raj¬ak, K. ipo2ova, Z. Gaoova, Z. Bednarikova, N. Toma2ovicova, Chin-Kun Hu, S. Hayryan, I. Studenyak , T.M. Kovalchuk and O.V. Kovalchuk Institute of Experimental Physics, Slovak Academy of Sciences, Ko2ice, Slovakia Faculty of Aeronautics, Technical University, Ko2ice, Slovakia Institute of Molecular Physics, Polish Academy of Sciences, Pozna«, Poland Department of Biochemistry, Institute of Chemistry, P.J. Safarik University in Ko2ice, Slovakia Institute of Physics, Academia Sinica, 128 Sec.2, Academia Rd., Nankang, Taipei 11529, Taiwan Physics Faculty, Uzhhorod National University, Uzhhorod, 88000, Ukraine Institute of Semiconductor Physics, National Academy of Science of Ukraine, Kyiv, Ukraine Kyiv National University of Technologies and Design, Kyiv, Ukraine An important feature of lyotropic liquid crystals is the self-assembly of the amphiphilic molecules as supermolecular structures. We have studied the formation of nematic liquid crystal phase in solutions containing lysozyme amyloid brils and magnetic nanoparticles using oscilloscopic method. Interaction of brils with magnetic nanoparticles under the external magnetic eld resulted in bril re-arrangement. The analysis of the obtained results suggests that the decrease in conductivity of solutions in presence of magnetic eld is due to decrease of the ion mobility caused by re-arrangement of structures in the solution. The obtained results allow determination of the optimum ratio of the components which can lead to preparation of solutions with a more ordered structure in presence of magnetic eld.