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Wyszukujesz frazę "Timko, M." wg kryterium: Autor


Tytuł:
Thermoelectric Properties of $CeCu_4Ag$ Compound
Autorzy:
Kowalczyk, A.
Toliński, T.
Falkowski, M.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1534756.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.80.-g
72.15.Cz
72.20.Pa
Opis:
The magnetic and electronic properties including electrical resistivity, thermal conductivity and thermopower are discussed for the heavy fermion $CeCu_4Ag$ compound. The electrical resistivity shows a Kondo-like logarithmic increase up to a maximum at T = 75 K. Thermopower is positive over the whole temperature range and below $T_\text{max}$ = 25 K falls rapidly. The measured thermal conductivity of the $CeCu_4Ag$ compound increases with increasing temperature.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 936-937
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Valence Band and Core Levels of $Ce_5Ni_2Si_3$ Crystal Studied by X-ray Photoemission Spectroscopy
Autorzy:
Toliński, T.
Kowalczyk, A.
Chełkowska, G.
Mihalik, M.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813673.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
82.80.Pv
Opis:
The crystal of $Ce_5Ni_2Si_3$ was prepared by the Czochralski method. The X-ray photoemission spectroscopy was measured for the valence band and the core levels. Based on the Ce(3d) doublet and its satellites a small value of the hybridization parameter of the f-states with the conduction electrons Δ=4 meV and the f-occupancy $n_f$ close to 1 were found. X-ray photoemission spectroscopy shows that the region between 0 and 3 eV is predominated by the Ni(3d) and Ce(4f) peaks. Some features of the multiplet structure of the Ce(4f) states are also visible close to the Fermi level.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 327-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$[FeCl_{4}]¯$ Ionic Liquid Based Ferrofluids
Autorzy:
Parnica, J.
Kesa, P.
Kovac, J.
Timko, M.
Antalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368745.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kp
75.50.Bb
47.65.Cb
75.50.Mm
Opis:
Magnetic ionic liquids derived from hydrochloride methyl ester alanine amino acids (AA) and $FeCl_{3}$ were synthesized in ethanol and their magnetic properties were investigated. Iron (III) chloride forms ionic liquid in ethanol at saturated concentrations by the transfer of Cl¯ anion from one molecule of $FeCl_{3}$ to the other molecule with the creation of tetrachloro ferrate anion $[FeCl_{4}]$¯ as well as dimer $[Fe_{2}Cl_{7}]$¯. Raman scattering indicates that after addition of hydrochloride methyl ester alanine to ethanol solutions of $FeCl_{3}$ increase the intensities of signal at the frequencies at 318 $cm^{-1}$ and 380 $cm^{-1}$ as markers for the presence of $[FeCl_{4}]$¯ and $[Fe_{2}Cl_{7}]$¯ complexes. The magnetization at room temperature showed in both samples a linear dependence on the applied magnetic field. On the other hand, in the Raman scattering experiments the magnetization is smaller for $FeCl_{3}$ sample in the presence of methyl ester alanine.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 276-277
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Temperature on the Magneto-Dielectrics Effect of Oil-Based Ferrofluid
Autorzy:
Kúdelčík, J.
Hardoň, Š.
Bury, P.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1030417.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.65.Cb
77.22.Gm
77.22.Ch
Opis:
The effect of temperature on the magneto-dielectrics behavior was studied by dielectric spectroscopy in the transformer oil-based ferrofluid with magnetic nanoparticles upon the effect of an external magnetic field. The frequency dependence of complex permittivity and dissipation factor were measured within the frequency range from 1 mHz to 10 kHz at different temperatures by a capacitance method. The dielectrics parameters were measured as a function of the external magnetic field in the range of 0-200 mT, parallel to the direction of the electric field as a function of temperature in the range of 15-35°C. The interaction between magnetic field and magnetic moments of nanoparticles led to the aggregation of magnetic nanoparticles to new structures which had influence on dielectric parameters. The dependence of these parameters at constant magnetic field on angle between the direction of the electric and magnetic fields (anisotropy) has been measured, too.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 483-485
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Polymer Immobilization on Magnetic Properties of Magnetosomes
Autorzy:
Timko, M.
Džarová, A.
Kovač, J.
Kopčanský, P.
Gojzewski, H.
Powiązania:
https://bibliotekanauki.pl/articles/1535115.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.30.Gw
75.50.Mm
75.50.Tt
75.60.Ej
Opis:
The anisotropy of several PVA/magnetosomes magnetically textured films has been investigated from the point of view of magnetic properties. The thin film synthesized under the influence of a magnetic field (99 mT) shows the typical behavior of an anisotropic material. On sample textured in magnetic field the magnetisation loop measurements were performed in dependence on the direction of the external magnetic field with respect to the texture axis. The results of hysteresis measurements show that the magnetic field applied during the synthesis promotes an orientation of the chains of magnetosomes and permanently textured film is obtained after solidification. The obtained values for magnetic remanence and coercivity were dependent on the external magnetic field orientation and the alignment effect of particle moments may be clearly seen which is in agreement with the theoretical model of magnetic particle chains.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 995-997
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Composites Consisting of High-T$\text{}_{c}$ Superconductor and Fine Magnetic Particles
Autorzy:
Timko, M.
Kopčanský, P.
Kováč, J.
Koneracká, M.
Plecháček, V.
Powiązania:
https://bibliotekanauki.pl/articles/2013009.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.Hs
75.50.Tt
Opis:
The composite systems as a mixture of fine magnetic particles of Fe$\text{}_{3}$O$\text{}_{4}$ and superconducting powder such as Bi$\text{}_{1.8}$Pb$\text{}_{0.2}$Sr$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{10+x}$ were prepared. The influence of internal magnetic field (generated by magnetic particles) on the superconducting properties of prepared composites were studied as a function of concentration of magnetic particles and their magnetic state. The observed data both of the shielding and the Meissner effect were compared with corresponding linear combination of pure signals of magnetite and superconductor, respectively. The large differences were observed for demagnetized samples. It means that result must be discussed in the frame of the distribution of internal magnetic field created by the magnetic particles.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 389-392
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Structural Changes of Water-Based Magnetic-Fluid by Acoustic Spectroscopy
Autorzy:
Kúdelčík, J.
Hardoň, Š.
Bury, P.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032248.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Mm
75.75.Jn
Opis:
The effect of an external magnetic field on the changes in structural arrangement of magnetic nanoparticles in water based magnetic fluid was studied by acoustic spectroscopy. When a magnetic field is increased, the interaction between the magnetic field and the magnetic moments of nanoparticles leads to the orientation of magnetic nanoparticles and their following aggregation to long chains that cause the increase of acoustic attenuation. The attenuation of acoustic waves measured for jump changes of the magnetic field to 100, 200, and 300 mT at temperature 20°C showed that the changes of acoustic attenuation increased slowly to a stabilized state that after switching off the magnetic field decreased immediately to initial value. The dependence of attenuation of acoustic waves at constant magnetic field on angle between the wave vector and direction of the applied magnetic field (attenuation anisotropy) has been measured, too. The measured anisotropy of acoustic attenuation attested structural changes of magnetic fluid in the magnetic field.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 919-921
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Magnetoferritin
Autorzy:
Mitróová, Z.
Melníková, L.
Kováč, J.
Timko, M.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1429123.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Cr
75.50.Ee
75.60.Ej
75.50.Tt
Opis:
The paper presents detailed experimental study of synthesis and characterization a bioinorganic magnetic molecule - magnetoferritin. Magnetoferritin with loading of iron ions per protein molecule in the range from 300 to 3000 was prepared. Size distribution analysis (transmission electron microscopy, dynamic light scattering) shows spherical nanoparticles with particle size distribution from 2 to 12 nm, and hydrodynamic diameter from 12 to 25 nm. The thermomagnetic curves measured after cooling the sample in zero field (zero-field cooling) and under the presence of the measurement field (field cooling) show superparamagnetic behavior with the blocking temperature $T_{b}$ from 22 to 60 K and the magnetization loops measured below $T_{b}$ (at 2 K) show the hysteresis with coercive field from 20 to 30 kA/m depending on the concentration of the magnetic nanoparticles.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1318-1320
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of Susceptibility and Optical investigation of the Antiferromagnetic phase Transition in U$\text{}_{1-x}$Ce$\text{}_{x}$Ru$\text{}_{2}$Si$\text{}_{2}$
Autorzy:
Mihalik, M.
Maťaš, S.
Macko, D.
Timko, M.
Menovsky, A. A.
Powiązania:
https://bibliotekanauki.pl/articles/1955512.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Hb
75.20.Hr
72.15.-v
Opis:
Temperature dependence of magnetic susceptibility of U$\text{}_{1-x}$Ce$\text{}_{x}$Ru $\text{}_{2}$Si$\text{}_{2}$ single crystals (x=0, 0.025, 0.05, 0.075) has been studied at temperatures from 4.2 K up to room temperature and in magnetic fields applied along and perpendicular to the c-axis. The attention was paid to anomalies connected with the antiferromagnetic phase transition, which are present in crystals with x≤0.05. Far-infrared measurements of U$\text{}_{0.99}$Ce$\text{}_{0.01}$ Ru$\text{}_{2}$Si$\text{}_{2}$ single crystal have been studied for the first time. The measurements support the assumption that the origin of magnetic ordering in U$\text{}_{0.99}$Ce$\text{}_{0.01}$Ru$\text{}_{2}$Si$\text{}_{2}$ is the same as in heavy-fermion superconductor URu$\text{}_{2}$Si$\text{}_{2}$ and can be interpreted as being due to a spin-density-wave gap.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 351-354
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Sonication on Acoustic Properties of Biogenic Ferroparticle Suspension
Autorzy:
Józefczak, A.
Hornowski, T.
Król, A.
Molčan, M.
Leszczyński, B.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/176978.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
magnetosomes
sonication
ultrasonic properties
Opis:
Superparamagnetic iron oxide nanoparticles (SPION) synthesised chemically usually need the modification of the particle surface. Other natural sources of magnetic particles are various magnetotactic bacteria. Magnetosomes isolated from magnetotactic bacteria are organelles consisting of magnetite (Fe3O4) or greigite (Fe3S4) crystals enclosed by a biological membrane. Magnetotactic bacteria produce their magnetic particles in chains. The process of isolation of magnetosome chains from the body of bacteria consists of a series of cycles of centrifugation and magnetic decantation. Using a high-energy ultrasound it is possible to break the magnetosome chains into individual nanoparticles – magnetosomes. This study presents the effect of sonication of magnetosome suspension on their acoustic properties, that is speed and attenuation of the sound. Acoustic propagation parameters are measured using ultrasonic spectroscopy based on FFT spectral analysis of the received pulses. The speed and attenuation of ultrasonic waves in magnetosome suspensions are analysed as a function of frequency, temperature, magnetic field intensity, and the angle between the direction of the wave and the direction of the field.
Źródło:
Archives of Acoustics; 2016, 41, 1; 161-168
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Changes in Liquid Crystals Doped with Rod-Like Magnetic Particles Studied by Surface Acoustic Waves
Autorzy:
Bury, P.
Veveričík, M.
Kúdelčík, J.
Kopčanský, P.
Timko, M.
Závišová, V.
Powiązania:
https://bibliotekanauki.pl/articles/1032787.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Gd
75.50.Mm
43.35.Bf
Opis:
The effect of rod-like magnetic particles on liquid crystal (6CHBT) structural changes in electric and weak magnetic fields were studied by means of the attenuation of surface acoustic wave of frequency 30 MHz propagating along ferronematic liquid crystals. Three low volume concentrations (Φ=1×10¯⁵, 1×10¯⁴ and 1×10¯³) of rod-like magnetic particles were added to liquid crystal during its isotropic phase. Several measurements including the investigation of the effects of electrical and magnetic fields applied both separately and in conjunction as well as the influence of temperature on the surface acoustic wave attenuation were performed. The distinctive surface acoustic wave attenuation responses induced by both electric and magnetic fields in studied ferronematic liquid crystals have been observed suggesting both structural changes and the orientational coupling between magnetic moments of magnetic particles and the director of the liquid crystal. Obtained results confirmed the significant influence of the presence of magnetic particles on the structural properties and resulting behavior of 6CHBT liquid crystal.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 913-915
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Charcoal Supporting Silver as a Water Disinfectant
Autorzy:
Valušová, E.
Antalík, M.
Pristaš, P.
Javorský, P.
Kováč, J.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1201874.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
75.60.Ej
75.47.Lx
81.05.U-
92.40.qc
Opis:
We investigated the magnetic behavior of charcoal composite with incorporated magnetite and silver ions. The magnetization curve measured at 282 K showed saturation magnetization of 8 emu/g. By benefiting from a mechanical process, the magnetic activated carbon, supporting silver ions (MCAG), acts as a magnetic filter uptaking the bacteria. This idea was confirmed by the DGGE analysis in which the bacterial DNA was detectable in the sediment after the treatment.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 226-227
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electro-rheological properties of transformer oil-based magnetic fluids
Autorzy:
Paulovičová, K.
Tóthová, J.
Rajňák, M.
Timko, M.
Kopčanský, P.
Lisý, V.
Powiązania:
https://bibliotekanauki.pl/articles/1053029.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.55.Jg
75.50.Mm
83.85.Jn
83.60.Np
Opis:
The aim of this work was to study rheological behavior of nanofluids affected by electric field and temperature. We used transformer oil-based magnetic fluids, the suspensions of permanently magnetized colloidal particles (Fe_3O_4) coated by a stabilizing surfactant and immersed in transformer oil. The rheological characterization of transformer oil-based magnetic fluid was performed using the rotational rheometer MCR 502 in the shear rate from 10 to 1000 s¯¹.The strength of electric field was changed in the interval 0-6 kV cm¯¹. The flow curves and viscosity functions detected at three different temperatures 25, 50, and 75°C disclose rheological characteristics of samples, first of all the viscosity growth under increasing strength of electric field.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1141-1143
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Encapsulated Magnetite in PLGA Nanospheres
Autorzy:
Koneracká, M.
Závišová, V.
Timko, M.
Kopčanský, P.
Tomašovičová, N.
Csach, K.
Powiązania:
https://bibliotekanauki.pl/articles/1813943.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Rv
75.50.Mm
87.83.+a
Opis:
In this study, the biocompatible magnetic fluid was encapsulated in biodegradable polymer PLGA (poly D, L/lactide-co-glycolide acid) by the nanoprecipitation method. We characterized these spheres in terms of morphology, magnetite content and magnetic properties. The results showed good encapsulation with magnetite content 22wt% and magnetization 3.4 mT. The transmission electron microscopy and scanning electron microscopy images showed that magnetic particles have almost a spherical shape with approximate size 250 nm. Infrared spectroscopy and thermogravimetric analysis measurements were used to confirm incorporation of magnetic particles into the PLGA polymer.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 595-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure and Transport Properties of UFe$\text{}_{2}$ System
Autorzy:
Szlaferek, A.
Szajek, A.
Baszyński, J.
Smardz, L.
Kowalczyk, A.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/2013662.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.La
71.20.Lp
72.15.Eb
Opis:
The electronic structure of the UFe$\text{}_{2}$ compound was studied by X-ray photoemission spectroscopy and ab initio self-consistent tight binding muffin tin orbital method. This compound crystallizes in a cubic Laves phase. The calculated valence band spectrum is characterized by two peaks due to U(5f) and Fe(3d) states. We have found a good agreement between the experimental valence band spectrum and theoretical ab initio calculations. The carrier concentration estimated from the Hall effect amounts to ≈10$\text{}^{22}$ cm$\text{}^{-3}$.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 815-818
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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