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Wyszukujesz frazę "Kołtunowicz, T." wg kryterium: Autor


Wyświetlanie 1-7 z 7
Tytuł:
Percolation Phenomena in $Cu_{x}(SiO_{y})_{100-x}$ Nanocomposite Films Produced by Ion Beam-Sputtering
Autorzy:
Koltunowicz, T.
Zukowski, P.
Czarnacka, K.
Svito, I.
Fedotov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402230.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.37.+q
72.80.Ga
73.22.-f
61.46.Df
64.60.ah
Opis:
In this paper the results of examinations of nanocomposites $Cu_{x}(SiO_{y})_{100-x}$ produced by ion beam sputtering using argon ions were presented. The examinations were performed by the use of ac devices for measuring frequency in the range 50 Hz-1 MHz and temperatures from 81 K to 273 K. The measurements were performed for the samples directly after production. Based on temperature dependences of conductivity σ , which were determined at the frequency 100 Hz, the Arrhenius graphs were prepared. From these graphs conductivity activation energies ΔE were calculated. Dependences of conductivity and activation energy of electrons on the metallic phase content x at the frequency 100 Hz were determined. Analysis of the obtained dependences shows that conductivity is a parabolic function of the metallic phase content x in nanocomposites. Changes of activation energies of nanocomposites, in which metallic phase contents are in the ranges x < 12 at.% and x > 68 at.%, demonstrate negative values - metallic type of conductivity. In the range 12 at.% < x < 68 at.% activation energies have positive values - the dielectric type of conductivity. It was established that for the metallic phase content of about 68 at.% the real percolation threshold occurs, and the conduction changes from dielectric to metallic type.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 908-911
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Temperature DC Carrier Transport in $(Co_{0.45}Fe_{0.45}Zr_{0.10})_{x}(Al_2O_3)_{1-x}$ Nanocomposites Sputtered in Mixed Argon-Oxygen Atmosphere
Autorzy:
Svito, I.
Fedotov, A.
Saad, A.
Koltunowicz, T.
Zukowski, P.
Bury, P.
Powiązania:
https://bibliotekanauki.pl/articles/1366313.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
72.20.Ee
64.60.ah
Opis:
This paper studies the temperature dependences (2 < T < 300 K) of the DC conductivity σ(T) for the $(Co_{0.45}Fe_{0.45}Zr_{0.10})_x(Al_2O_3)_{1-x}$ nanocomposites (30 < x < 65 at.%) sputtered in Ar + $O_2$ atmosphere. It is shown that at temperatures lower than 100-150 K dependences of DC conductance on temperature for all the studied samples are due to the Shklovski-Efros variable range hopping mechanism. It was also observed that σ(x,T) dependences can be attributed to the formation of FeCo-based oxide "shells" around metallic alloy nanoparticles due to incorporation of oxygen in the vacuum chamber during the deposition procedure.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1351-1354
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanisms of Carrier Transport in $Cu_x(SiO_2)_{1-x}$ Nanocomposites Manufactured by Ion-Beam Sputtering with Ar Ions
Autorzy:
Fedotov, A.
Mazanik, A.
Svito, I.
Saad, A.
Fedotova, V.
Czarnacka, K.
Koltunowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402220.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.37.+q
72.80.Ga
73.22.-f
61.46.Df
64.60.ah
Opis:
The present paper investigates the temperature/frequency dependences of admittance Z in the granular $Cu_x(SiO_2)_{1-x}$ nanocomposite films around the percolation threshold $x_{C}$ in the temperature range of 4-300 K and frequencies of 20-10⁶ Hz. The behavior of low-frequency ReZ(T) dependences displayed the predominance of electrons hopping between the closest Cu-based nanoparticles for the samples below the percolation threshold $x_{C}$ ≈ 0.59 and nearly metallic behaviour beyond the $x_{C}$. The high-frequency curves ReZ(f) at temperatures T > 10 K for the samples with x < $x_{C}$ exhibited behavior close to ReZ(f) ≈ $f^{-s}$ with s ≈ 1.0 which is very similar to the known Mott law for electron hopping mechanism. For the samples beyond the percolation threshold (x > $x_{C}$), the frequency dependences of ReZ(f) displayed inductive-like (not capacitive) behaviour with positive values of the phase shift angles.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 883-886
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Voltage and Current Resonance in Nanocomposite $(FeCoZr)_x(CaF_2)_{100-x}$ Produced by Ion-Beam Sputtering in Pure Argon Atmosphere
Autorzy:
Koltunowicz, T.
Zukowski, P.
Bondariev, V.
Fedotov, A.
Svito, I.
Fedotova, J.
Saad, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402224.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.23.Pq
79.20.Rf
81.40.Ef
72.80.Le
Opis:
In this paper the results of investigations of electrical properties of metal-dielectric nanocomposites $(FeCoZr)_x(CaF_2)_{100-x}$ are presented. The samples with the metallic phase content x=45.7 at.% were produced by ion-beam sputtering method in pure argon atmosphere, and subsequently annealed at 398 K for 15 min. The measurements of electrical properties were performed in the frequency range from 50 Hz to 1 MHz. The frequency dependences of phase angle θ, capacity $C_{p}$, conductivity σ and dielectric loss factor tanδ were measured at seven different temperatures ranging from 148 K to 263 K. It was found that the nanocomposite exhibits the phenomena of voltage resonance and current resonance, characteristic of the conventional RLC circuits with series and parallel connections of elements.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 897-900
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ion Irradiation of Oxidized FeCoZr-CaF₂ Nanocomposite Films for Perpendicular Magnetic Anisotropy Enhancement
Autorzy:
Kasiuk, J.
Fedotova, J.
Przewoźnik, J.
Kapusta, C.
Skuratov, V.
Svito, I.
Bondariev, V.
Kołtunowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1030130.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Tt
75.30.Gw
81.15.Jj
81.40.Wx
81.40.Rs
61.80.Jh
Opis:
The paper is focused on the results of Xe ions irradiation of nanocomposite FeCoZr-CaF₂ films synthesized in the oxygen-containing atmosphere. Combined influence of nanoparticles partial oxidation and ion irradiation with different fluences on the crystalline structure, phase composition and magnetic anisotropy is analysed by X-ray diffraction, the Mössbauer spectroscopy and vibrating sample magnetometry. The origin of the detected progressive enhancement of perpendicular magnetic anisotropy as the result of films oxidation and irradiation is discussed in the context of formation of nanoparticles oxide shells and ion tracks along the films normal.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 206-209
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric Properties of $Ca_3Co_4O_9$-Based Ceramics Doped with Fe and/or Y
Autorzy:
Fedotov, A.
Mazanik, A.
Svito, I.
Saad, A.
Troyanchuk, I.
Bushinski, M.
Fedotova, V.
Zukowski, P.
Koltunowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1366301.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.25.Hf
62.20.D-
82.45.Xy
Opis:
We describe here structure and temperature dependences of conductivity σ(T), the Seebeck coefficient α(T), thermal conductivity λ(T) and figure-of-merit ZT(T) in $Ca_3Co_4O_9$ ceramics, doped with Fe and Y, depending on compacting pressure (0.2 or 6 MPa) and temperature (300 < T < 700 K). It is shown that introduction of iron and yttrium to ceramics does not alter the crystalline structure of the material. Increasing the pressure in the compacting process before the additional diffusion annealing leads to a smaller-grained structure and increase σ and λ due to reducing of the synthesized samples porosity. The Seebeck coefficients of nanocomposite ceramics $Ca_3Co_{3.9}Fe_{0.1}O_9$ and $(Ca_{2.9}Y_{0.1})(Co_{3.9}Fe_{0.1})O_9$ have linear dependences on temperature is not changed after increase of compacting pressure. Electrical-to-heat conductivity ratio (σ/λ) for the samples compacted at high (6 GPa) pressure increases not more than 20-30% in comparison with ones compacted at low (0.2 GPa) pressure, whereby ZT is increased more than 50%. The main reason for this effect is samples porosity reduction with the compacting pressure increase.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1344-1347
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoresistance in n-Si/$SiO_2$/Ni Nanostructures Manufactured by Swift Heavy Ion-Induced Modification Technology
Autorzy:
Fedotova, J.
Ivanou, D.
Ivanova, Y.
Fedotov, A.
Mazanik, A.
Svito, I.
Streltsov, E.
Saad, A.
Tyutyunnikov, S.
Kołtunowicz, T.
Demyanov, S.
Fedotova, V.
Powiązania:
https://bibliotekanauki.pl/articles/1504014.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Ln
81.05.Rm
73.22.-f
73.50.Jt
Opis:
A study of magnetotransport in the n-Si/$SiO_2$/Ni nanostructures with granular Ni nanorods in $SiO_2$ pores was performed over the temperature range 2-300 K and at the magnetic fields induction up to 8 T. The n-Si/$SiO_2$/Ni Schottky nanostructures display the enhanced magnetoresistive effect at 25 K due to the impurity avalanche mechanism.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 133-135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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