Temat: 74 - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Clean bulk YBaCuO superconductors doped by paramagnetic ions of Sm and Yb
Autorzy:: Jirsa, M.
Volochová, D.
Kováč, J.
Diko, P.
Powiązania:: https://bibliotekanauki.pl/articles/1054700.pdf
Data publikacji:: 2017-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Op
74.25.Sv
74.60.Ge
74.72.-h
Opis:: The recently developed clean cuprate technology was employed to study the effect of tiny amounts of paramagnetic Yb and Sm ions on electromagnetic properties of bulk YBaCuO. Small samples of about 1.5×1.5×0.5 mm³ were measured by vibrating sample magnetometer in the field range ±9 T and temperatures 30 K to 10 K in the non-superconducting tetragonal state and 300 K to 70 K in the orthorhombic, superconducting state. In the latter case, we observed the reversible paramagnetic moment above T_{C}, similar as in the tetragonal state. Below T_{C} an irreversible magnetic moment was observed from which critical current density, J_c, was evaluated using the extended Bean model. The effect of doping by Yb and Sm ions on J_c was studied and a correlation between J_c and the total paramagnetic moment was found. Both J_c(B) and the normalized pinning force density as a function of the reduced magnetic field were analyzed in terms of the classical model and discussed with respect to the material anisotropy, giving us at least a rough idea on the type of the effective pinning type and mechanism.
Źródło:: Acta Physica Polonica A; 2017, 131, 4; 1027-1029
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Magnetoresistance study of c-axis oriented YBCO thin film
Autorzy:: Chrobak, M.
Woch, W.
Kowalik, M.
Zalecki, R.
Giebułtowski, M.
Przewoźnik, J.
Kapusta, Cz.
Szwachta, G.
Powiązania:: https://bibliotekanauki.pl/articles/1054863.pdf
Data publikacji:: 2017-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.78.-w
74.25.Op
74.25.Qt
74.78.Bz
Opis:: The c-axis orientation YBa₂Cu₃O_δ thin film was prepared directly on MgO substrate by the pulse laser deposition. The thickness of the film is 170 nm. The superconducting critical temperature is T_{c50%}=87.5 K and the width of superconducting transition is ΔT = 1.8 K. The temperature dependences of magnetoresistance were measured up to 90 kOe. The widths of the transition to the superconducting state versus applied magnetic field were derived and they were fitted using the formula: Δ T=CH^m +Δ T₀. The irreversibility fields as a function of temperature were obtained and fitted by the de Almeida and Thouless-like equation: H_{irr}=H_{irr0}(1-T/T_{c0})^n. The irreversibility field at the liquid nitrogen temperature was calculated and it is H_{irr}=43.8 kOe when the applied magnetic field is parallel to the c-axis.
Źródło:: Acta Physica Polonica A; 2017, 131, 4; 1018-1020
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: The Fulde-Ferrell-Larkin-Ovchinnikov Superconductivity in Disordered Systems
Autorzy:: Ptok, A.
Powiązania:: https://bibliotekanauki.pl/articles/1537270.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.20.Mn
74.20.Rp
74.25.Dw
74.81.-g
Opis:: The Fulde-Ferrell-Larkin-Ovchinnikov phase, with a spatially oscillating order parameter, may be induced by strongly magnetic field at low temperature. It is believed that the Fulde-Ferrell-Larkin-Ovchinnikov phase can exist only in homogeneous superconductors, and even weak impurity potential can lead to its destruction. The analysis of the Fulde-Ferrell-Larkin-Ovchinnikov phase in the Bogoliubov-de Gennes equation shows however, that this phase can exist in the presence of weak disorder. Using Bogoliubov-de Gennes equations, we discussed the influence of diagonal and off-diagonal disorder on the Fulde-Ferrell-Larkin-Ovchinnikov phase.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 420-422
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Vortex Motion and Quasiparticle Resistivity in Superconductors at Microwave Frequencies
Autorzy:: Sarti, S.
Amabile, C.
Fastampa, R.
Giura, M.
Silva, E.
Pompeo, N.
Powiązania:: https://bibliotekanauki.pl/articles/2047225.pdf
Data publikacji:: 2007-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Nf
74.20.De
74.60.Ge
74.70.Ad
74.72.-h
Opis:: At nonzero frequencies both the normal and superfluid fractions, as well as moving vortices, contribute to the electrical transport, resulting in intricate expressions for the resistivity. We present an extended study of microwave resistivity data measured on YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$, SmBa$\text{}_{2}$ Cu$\text{}_{3}$O$\text{}_{7-δ}$, and MgB$\text{}_{2}$ by means of a broad-band technique between 2 and 20 GHz and of a resonant system at 50 GHz. We discuss the main experimental fingerprints that allow one to identify the relevance of the different contributions from the measured microwave response as a function of frequency, temperature, and magnetic field. We show that the field-dependent superfluid/quasiparticles dynamics cannot be in general neglected with respect to the vortex motion, albeit its relative importance is different in different materials: in high temperature superconductors vortex motion prevails at high fields, but at low fields a significant superfluid/quasiparticle contribution exists (ascribed to the presence of lines of nodes). In MgB$\text{}_{2}$ the two contributions are comparable even at high fields. In this general frame, we derive from the measurements vortex and superfluid parameters in agreement with theoretical predictions and independent measurements.
Źródło:: Acta Physica Polonica A; 2007, 111, 1; 87-93
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Obtaining a Rough Flux Front in Type-II Superconductors Using a Critical State Model
Autorzy:: Romero-Salazar, C.
Hernández-Flores, O.
Chabanenko, V.
Kuchuk, E.
Abaloszewa, I.
Nabialek, A.
Pérez-Rodríguez, F.
Powiązania:: https://bibliotekanauki.pl/articles/1398648.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.20.De
74.25.Ha
74.25.N-
74.25.Op
74.25.Sv
74.25.Wx
74.62.Dh
74.81.-g
Opis:: In this work we numerically modelled a periodic magnetic flux pattern which qualitatively reproduces the so-called sand avalanches scenario in type-II superconductors. To model these sand-pile patterns we consider a perturbation on the critical current which, as a first approximation, follows a periodic function which depends on the position.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 645-648
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Nanostructural Superconducting Materials for Fault Current Limiters and Cryogenic Electrical Machines
Autorzy:: Prikhna, T.
Gawalek, W.
Savchuk, Ya.
Sergienko, N.
Moshchil, V.
Sokolovsky, V.
Vajda, J.
Tkach, V.
Karau, F.
Weber, H.
Eisterer, M.
Joulain, A.
Rabier, J.
Chaud, X.
Wendt, M.
Dellith, J.
Danilenko, N.
Habisreuther, T.
Dub, S.
Meerovich, V.
Litzkendorf, D.
Nagorny, P.
Kovalev, L.
Schmidt, Ch.
Melnikov, V.
Shapovalov, A.
Kozyrev, A.
Sverdun, V.
Kosa, J.
Vlasenko, A.
Powiązania:: https://bibliotekanauki.pl/articles/1549637.pdf
Data publikacji:: 2010-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Sv
74.81.Bd
74.70.Ad
74.78.Na
74.62.Fj
74.25.Ld
74.62.Dh
74.25.Ha
Opis:: Materials of the Y-Ba-Cu-O (melt-textured $YBa_{2}Cu_{3}O_{7-δ}$-based materials or MT-YBCO) and Mg-B-O ($MgB_{2}$-based materials) systems with high superconducting performance, which can be attained due to the formation of regularly distributed nanostructural defects and inhomogeneities in their structure can be effectively used in cryogenic technique, in particular in fault current limiters and electrical machines (electromotors, generators, pumps for liquid gases, etc.). The developed processes of high-temperature (900-800°C) oxygenation under elevated pressure (16 MPa) of MT-YBCO and high-pressure (2 GPa) synthesis of $MgB_{2}$-based materials allowed us to attain high superconductive (critical current densities, upper critical fields, fields of irreversibility, trapped magnetic fields) and mechanical (hardness, fracture toughness, Young modulus) characteristics. It has been shown that the effect of materials properties improvement in the case of MT-YBCO was attained due to the formation of high twin density (20-22 $μm^{-1}$), prevention of macrocracking and reduction (by a factor of 4.5) of microcrack density, and in the case of $MgB_{2}$-based materials due to the formation of oxygen-enriched as compared to the matrix phase fine-dispersed Mg-B-O inhomogeneities as well as inclusions of higher borides with near-$MgB_{12}$ stoichiometry in the Mg-B-O matrix (with 15-37 nm average grain sizes). The possibility is shown to obtain the rather high $T_{c}$ (37 K) and critical current densities in materials with $MgB_{12}$ matrix (with 95% of shielding fraction as calculated from the resistant curve).
Źródło:: Acta Physica Polonica A; 2010, 117, 1; 7-14
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: d-Wave Superconductivity in a System with Open Boundary Conditions
Autorzy:: Pisarski, P.
Harań, G.
Powiązania:: https://bibliotekanauki.pl/articles/2041464.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Rp
74.72.-h
74.78.Na
74.81.-g
Opis:: We discuss the d-wave superconductivity in confined geometry by imposing open boundary conditions on the attractive Hubbard model. Within the Bogoliubov-de Gennes approach we evaluate the order parameter and charge density distribution in the system.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 721-725
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Critical Current Problems in HTc Superconductors
Autorzy:: Sosnowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1536989.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Wx
74.25.Sv
74.25.Uv
Opis:: New results of the investigations critical current problems in the high temperature oxide superconductors are presented, basing on the flux pinning analysis. Model of the pinning interaction of the nanosized centers with pancake vortices is proposed, while comparison of the received results concerning the dependence of the potential barrier versus transport current with other pinning forces approaches is presented. Special attention is devoted to the investigations of the influence the initial position of the vortex captured at pinning center on the current-voltage characteristics and critical current.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 328-330
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Multiple Phase Slip Phenomena in the Narrow Superconducting Channels
Autorzy:: Baranov, V.
Balanov, A.
Kabanov, V.
Powiązania:: https://bibliotekanauki.pl/articles/1426736.pdf
Data publikacji:: 2012-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.40.Gh
74.81.-g
74.78.Na
74.40.De
Opis:: The current-voltage characteristic of the narrow superconducting channel is investigated by direct numerical integration of the time-dependent Ginzburg-Landau equations. We have demonstrated that the steps in the current-voltage characteristic correspond to a number of different bifurcation points of the time-dependent Ginzburg-Landau equations. We have analytically estimated the period and the averaged voltage of the oscillating solution for the relatively small currents. We have also found the range of currents where the system transforms to the chaos.
Źródło:: Acta Physica Polonica A; 2012, 121, 5-6; 1038-1041
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The Pressure Effects on Electronic Structure of Iron Chalcogenide Superconductors $FeSe_{1-x}Te_x$
Autorzy:: Ciechan, A.
Winiarski, M.
Samsel-Czekała, M.
Powiązania:: https://bibliotekanauki.pl/articles/1431323.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Pq
74.25.Kc
74.62.F
74.70.Xa
Opis:: We study the electronic structure of iron-based superconductors $FeSe_{1-x}Te_x$ within the density functional theory. We pay particular attention to the pressure effects on the Fermi surface (FS) topology, which seem to be correlated with a critical superconducting temperature $T_C$ of iron chalcogenides and pnictides. A reduction of the FS nesting between hole and electron cylinders with increasing pressure is observed, which can lead to higher values of $T_C$. The tellurium substitution into selenium sites yields FS changes similar to the pressure effect.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 820-823
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Investigation Details of Vortex Density in Laser-Written Π-Shaped Channel of YBCO Bridge by Means of I-V Dependences
Autorzy:: Steponaviciene, L.
Sulcas, J.
Jukna, A.
Jung, G.
Plausinaitiene, V.
Abrutis, A.
Maneikis, A.
Gong, M.
Sobolewski, R.
Powiązania:: https://bibliotekanauki.pl/articles/1505530.pdf
Data publikacji:: 2011-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.78.-w
74.25.Sv
74.25.F-
74.25.Wx
Opis:: A current-self-induced magnetic field $H_{j}$, such that $H_{c1} < H_{j} < H_{c2}$ at $T < T_{c}$, penetrates a thin-film, type-II superconductor forming the Abrikosov magnetic vortex-antivortex pairs in the film's areas of weakest superconductivity. Our atomic force microscopy and scanning tunneling microscopy images confirm that in 50 μm wide, 100 μm long and 0.3 μm thick $YBa_2Cu_3O_{7 - x}$ superconducting devices magnetic flux penetrates first into a 5 μm wide, Π-shaped and partially deoxygenated (x ≈ 0.2) channel for easy vortex motion. When the Lorentz force overcomes pinning force in the channel, the flux starts to move and its drift dissipates energy inducing dc voltage. This work reports on the density of coherently moving vortices along the channel vs. temperature in range from $0.93T_{c}$ to $0.97T_{c}$. Our simulations show that the vortex density vs. temperature dependence extracted from I-V measurements of our devices follows the temperature dependence of magnetic field penetration depth and the coherence length of the superconductor.
Źródło:: Acta Physica Polonica A; 2011, 119, 2; 180-182
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Current Distribution in Y-Ba-Cu-O Superconducting Microbridges Containing Π-Shaped Channel for Easy Vortex Motion
Autorzy:: Sulcas, J.
Steponaviciene, L.
Jukna, A.
Jung, G.
Plausinaitiene, V.
Abrutis, A.
Gong, M.
Sobolewski, R.
Powiązania:: https://bibliotekanauki.pl/articles/1505543.pdf
Data publikacji:: 2011-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.78.-w
74.25.Sv
74.25.F-
74.25.Wx
Opis:: A mixed state in dc-biased thin films of II-type superconductors realizes the Abrikosov magnetic vortices/antivortices, which are the result of the current-self magnetic field penetration into the film at temperatures lower than its critical temperature $T_{c}$. A nucleation of vortices/antivortices at the superconducting film's edges, their motion perpendicular to the direction of biasing current, and the annihilation in the film's center originates from a current dissipation in the superconductor and expresses itself in experiments as a dc voltage. This work reports on the results of simulation of current density in a 50 μm wide, 100 μm long, and 0.3 μm thick $YBa_2Cu_3O_{7 - x}$ microbridges containing Π-shaped 5 μm wide single channel of easy vortex motion fabricated by means of laser-writing technique. Analyzing a two-dimensional-net of resistors and assuming that, due to the Meissner-Ochsenfeld effect, the magnetic flux penetration into superconducting film is nonlinear, we demonstrate that presence of a Π-shaped channel causes a non-homogeneous distribution of current in the microbridge.
Źródło:: Acta Physica Polonica A; 2011, 119, 2; 183-185
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Improved Transresistance Characteristics of Inductance-gate Type SFFT Using AFM Lithography
Autorzy:: Ko, S.
Powiązania:: https://bibliotekanauki.pl/articles/1400571.pdf
Data publikacji:: 2015-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Pq
74.25.F-
74.25.Jb
74.55.+V
Opis:: An atomic force microscope (AFM) was used to locally anodize the serial channels of an inductance-gate type superconducting flux flow transistor (SFFT) as narrow slits with a width of 50 μm, a space of 25 μm, and 12 turns, to improve the transresistance value. Among the serial channels that were anodized with the scanning tip of the AFM in the drain current line, channels 1 and 2 were 7.3 and 7.9 μm wide, and 531 and 461 nm high, respectively. The critical current density in the serial channel of the fabricated SFFT, which was determined using an AFM modification method, was decreased by increasing the gate current. The measured current-voltage curves were compared with the simulated ones. The maximum transresistance value was 0.56 Ω at the drain current of 20 mA when the gate current was 6 mA. The transresistance characteristics of the inductance-gate type SFFT could be more improved than that of the single-channel type SFFT using an inductively coupled plasma lithography method
Źródło:: Acta Physica Polonica A; 2015, 127, 4; 928-930
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Vortex Pinning in Ferromagnet/Superconductor Bilayers - the Dependence on the Ferromagnetic Layer and Temperature
Autorzy:: Adamus, Z.
Cieplak, M. Z.
Abal'oshev, A.
Berkowski, M.
Kończykowski, M.
Cheng, X. M.
Shu, L. Y.
Chien, C. L.
Powiązania:: https://bibliotekanauki.pl/articles/2046703.pdf
Data publikacji:: 2006-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Qt
74.78.Db
74.78.Fk
Opis:: The behavior of vortex pinning induced by the magnetic domain reversal is studied in the ferromagnet/superconductor bilayers in which superconducting film is niobium and the ferromagnetic layers are the Co/Pt superlattices with perpendicular magnetic anisotropy. The local magnetic field across narrow ferromagnet/superconductor bilayer stripe is measured using a line of miniature Hall sensors. The pinning is studied for samples with different amount of repeats of Co/Pt superlattice, and as a function of temperature.
Źródło:: Acta Physica Polonica A; 2006, 109, 4-5; 451-456
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Two-Dimensional Behavior of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{x}$ Films on SrTiO$\text{}_{3}$ Substrates
Autorzy:: Mikheenko, P. N.
Lewandowski, S. J.
Powiązania:: https://bibliotekanauki.pl/articles/1964342.pdf
Data publikacji:: 1997-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.Dh
74.76.-w
74.80.-g
74.80.Dm
Opis:: Long-term (up to 18 months) degradation of textured YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{x}$ films prepared by laser ablation and magnetron sputtering on single crystal SrΤiO$\text{}_{3}$, MgO and Al$\text{}_{2}$O$\text{}_{3}$ substrates were investigated. All films at each stage of exposition displayed a clearly visible quasi-2D behavior. From the measurements of the Kosterlitz-Thouless temperature it could be concluded that the oxygen content and density of charge carriers remained constant. It follows that the main consequence of degradation is the omission of some planes from the transport of supercurrent and the samples could be described in the model of layered structure with variable number of conducting planes. Using this model we find that effective thickness of an isolated CuO$\text{}_{2}$ plane in samples with greatest internal damage is ≈2Å.
Źródło:: Acta Physica Polonica A; 1997, 92, 1; 152-156
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 16.

Tytuł:: AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates
Autorzy:: Zalecki, R.
Woch, W.
Chrobak, M.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1374144.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.F-
74.25.Ha
74.25.Sv
Opis:: The $YBa_2Cu_3O_δ$ films were obtained directly on silver substrates by the sedimentation processes. The thicknesses of these films are of the order of several tens μ. The temperature dependences of the AC susceptibility of the films were measured and analyzed. The critical temperatures of these specimens obtained from the dispersion part of AC susceptibility vary from 89.2 K to 92.5 K. The critical currents were calculated from the absorption part of AC susceptibility using the Bean model. The temperature dependences of the critical currents were fitted using the Ginzburg-Landau strong coupling limit approach.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-13-A-15
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 17.

Tytuł:: Effects of Europium-Barium Nonstoichiometry in EBCO123 Systems on Transition and Magnetization Properties
Autorzy:: Cigáň, A.
Maňka, J.
Kopčok, M.
Polovková, J.
Jurdák, P.
Koňakovský, A.
Powiązania:: https://bibliotekanauki.pl/articles/1813614.pdf
Data publikacji:: 2008-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.62.Bf
74.25.Fy
74.25.Ha
Opis:: We studied the effects of Eu-Ba nonstoichiometry in two series of $Eu_{1+x}Ba_{2-x}Cu_3O_{7-δ}$ and $Eu_{1-x}Ba_{2+x}Cu_3O_{7-δ}$ samples on transition, structural, and magnetic properties. The samples with the nominal composition of 0≤x≤0.07 were synthesized by the solid-state reaction method from $Eu_2O_3,$ $BaCO_3,$ and CuO precursors and sintered at 1050°C for 72 h in flowing oxygen. All the samples show the values of critical temperature $T_c$, volume density ρ, and maximum volume magnetization $M_\text{max}$ higher than 90 K, 6.3 g $cm^{-3}$ and $10^4 Am^{-1}$, respectively, except for x = 0.07 samples. The Eu-Ba nonstoichiometry in the two series shows different effects on transport, magnetization hystereses, and intergrain properties of the samples.
Źródło:: Acta Physica Polonica A; 2008, 113, 1; 219-222
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 18.

Tytuł:: Critical Currents of Bismuth 1G Tape
Autorzy:: Woch, W.
Zalecki, R.
Chrobak, M.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1385464.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.F-
74.25.Ha
74.25.Sv
Opis:: The critical currents of commercial bismuth based superconducting tape were determined in the two ways. In the first one the transport critical current density was measured by the four points method using the dc current power supply at the liquid nitrogen temperature. In the second one the critical current densities were obtained from the absorption part of ac susceptibility measurements using the Bean model near the critical temperature. The temperature dependence of the critical current densities was fitted to take advantage of the Ginzburg-Landau strong-coupling limit approach. Using the fit parameters the critical current density at 77 K was calculated. The critical temperature of this tape ($T_{c}$= 110.5 K) was determined from the ac susceptibility measurements.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 315-317
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 19.

Tytuł:: On the Ratio of the Energy Gap Amplitude to the Critical Temperature for Cuprates
Autorzy:: Szczęiśniak, R.
Durajski, A.
Powiązania:: https://bibliotekanauki.pl/articles/1382034.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.20.Fg
74.20.Mn
74.25.Bt
74.72.-h
74.72.Bk
74.72.Jt
Opis:: The model for the cuprates based on the modified electron-phonon pairing mechanism has been tested. For this purpose, the superconductors with high value of the critical temperature have been taken into consideration. In particular: $YBa_{2}Cu_{3}O_{7-y}$, $HgBa_{2}CuO_{4+y}$, $HgBa_{2}Cu_{1-x}Zn_{x}O_{4+y}$, and $HgBa_{2}Ca_{2}Cu_{3}O_{8+y}$. It has been shown that the dependence of the ratio $R_{1}$ ≡ $2Δ_\text{tot}^{(0)}$/$k_{B}T_{C}$ on the doping (p) can be properly predicted in the framework of the presented theory; the symbol $Δ_\text{tot}^{(0)}$ denotes the energy gap amplitude at the temperature of zero kelvin, and $T_{C}$ is the critical temperature. The numerical results have been supplemented by the formula which describes the function $R_{1}(p)$.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-92-A-96
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 20.

Tytuł:: Time Dependent Changes in Ag Doped YBCO Superconductors
Autorzy:: Volochová, D.
Antal, V.
Diko, P.
Šefčiková, M.
Zmorayová, K.
Kováč, J.
Weber, H.
Chaud, X.
Powiązania:: https://bibliotekanauki.pl/articles/1535451.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Sv
74.62.Bf
74.62.Dh
74.62.Fj
Opis:: Magnetization measurements at 77 K were conducted on the single-crystalline samples of YBCO superconductor doped with Ag prepared by the top-seeded melt-growth process. The single-grain samples had a nominal composition $Y_{1.5}Ba_2(Cu,Ag)_3O_{y}$. Magnetization measurements on the samples, oxygenated by two different processes: by standard oxygenation and by high pressure oxygenation, repeated after 24 months, revealed time dependent changes in magnetization behaviour and critical transition temperatures, T_{c}, which could be associated with redistribution of oxygen vacancies and their interaction with Ag dopant atoms.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1047-1048
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 21.

Tytuł:: Electromagnetic Properties of Melt-Grown YBaCuO Superconductors Doped by Gd and Sm
Autorzy:: Jirsa, M.
Rameš, M.
Volochová, D.
Radušovská, M.
Diko, P.
Powiązania:: https://bibliotekanauki.pl/articles/1371409.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Op
74.25.Sv
74.60.Ge
74.72.-h
Opis:: Electromagnetic properties of $YBa_{2}Cu_{3}O_{y}$ samples melt-grown in air and doped with small amounts of light rare earth (LRE) ions Gd and Sm were studied. The LRE doping creates a point-like disorder contributing to the second peak on the magnetization curve. In the field range of the second peak the average magnetic moment, $M_{av}$, deduced from the magnetization curves exhibited strong fluctuations. $M_{av}$ is commonly regarded as an equilibrium moment close to the thermodynamic reversible one, obeying in intermediate fields a logarithmic field dependence. However, in our experiments $M_{av}(B)$ curves failed to follow such a dependence below irreversibility line. $M_{av}(B)$ curves deduced from rather static measurements, done by SQUID magnetometer still showed the disturbance but significantly weaker. It indicates that this feature reflects the vortex dynamics in the second peak region. Its scaling with temperature was found to coincide with that of the pinning force.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 326-327
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 22.

Tytuł:: Specific Heat and Magnetoresistance of Y-, Tl- and Bi-Type High-Temperature Superconductors
Autorzy:: Zalecki, R.
Kozłowski, A.
Kołodziejczyk, A.
Gritzner, G.
Mair, M.
Powiązania:: https://bibliotekanauki.pl/articles/1955838.pdf
Data publikacji:: 1997-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.Fq
74.25.Ha
74.72.Bk
74.72.Hs
74.25.Bt
Opis:: Specific heat of polycrystalline DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ and Tl$\text{}_{0.58}$Pb $\text{}_{0.42}$Sr$\text{}_{1.6}$Ba$\text{}_{0.4}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{9}$ samples, as well as the single crystal of Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8}$ have been measured within the temperature interval from 50 to 250 K. For Dy- and Tl-specimens the pronounced jump in specific heat and apparent contribution from Gaussian fluctuations of superconducting order parameter close to T$\text{}_{c}$ have been observed. In contrary, for Bi-specimen only a rounded maximum within a broad interval around T$\text{}_{c}$ has been detected. Magnetoresistance measurements as a function of temperature just below T$\text{}_{c}$ have been carried out for Dy- and Tl-samples and the slopes of upper critical fields have been determined. The data have been analysed within a frame of Ginzburg-Landau-Abrikosov- Gorkov theory with additional Gaussian-like fluctuation term. The electronic specific heat coefficients γ, and the coherence length χ have been obtained.
Źródło:: Acta Physica Polonica A; 1997, 91, 2; 431-434
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 23.

Tytuł:: The Isotope Effect of Disordered Superconductors
Autorzy:: Mierzyńska, M.
Wysokiński, K. I.
Powiązania:: https://bibliotekanauki.pl/articles/2038392.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Bt
74.62.-c
74.62.Dh
Opis:: The isotope effects in disordered weak and strong coupling superconductors of different symmetries of the order parameter have been studied. We have found that even though weak localisation corrections to Eliashberg equations describe a strong degradation of transition temperature with disorder of s-wave superconductors, their influence on isotope coefficient is relatively weak. On the other hand the calculated change of relative isotope coefficient with T$\text{}_{c}$/T$\text{}_{c0}$ in homogeneous thin film materials is similar to that observed in high temperature superconductors.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 647-652
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 24.

Tytuł:: Relativistic Theory of Superconductivity: BCS vs. Bogolyubov-de Gennes Approaches
Autorzy:: Ciechan, A.
Donabidowicz, A.
Wysokiński, K. I.
Powiązania:: https://bibliotekanauki.pl/articles/2041454.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.20.Fg
74.20.Rp
Opis:: In this paper we shall present the results of numerical calculations of the superconducting characteristics (temperature dependence of the gap function and specific heat) for few different symmetries of the order parameter in relativistic theory of superconductivity. We shall discuss relevance of the results to describe newly discovered superconductors, particularly those containing heavy elements with strong spin-orbit coupling.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 699-702
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 25.

Tytuł:: Magnetic Properties of Milled and Thermal Relaxed YBa$\text{}_{2}$ (Cu$\text{}_{1-x}$Fe$\text{}_{x}$)$\text{}_{3}$O$\text{}_{y}$
Autorzy:: Timko, M.
Kováč, J.
Sargánková, I.
Zentková, M.
Mihalik, M.
Maťaš, S.
Čiasnohová, A.
Powiązania:: https://bibliotekanauki.pl/articles/1955517.pdf
Data publikacji:: 1997-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.90.+n
74.10.+v
74.70.-b
Opis:: The influence of the mechanical milling and subsequent thermal relaxation on magnetic and superconducting behaviour of YBa$\text{}_{2}$(Cu$\text{}_{1-x}$Fe $\text{}_{x}$)$\text{}_{3}$O$\text{}_{y}$ system has been studied. Two methods of heat treatment were used: Set I - slow cooling from 980°C in flowing O$\text{}_{2}$ and Set II - reducing at 770°C in flowing Ar$\text{}_{2}$ followed by reoxidation in flowing O$\text{}_{2}$ below 400°C. The transition to superconductivity, diamagnetic response, critical current density and the effective magnetic moment in the normal state have been estimated. Our measurements indicate that the reducing atmosphere preparation is less detrimental on superconducting properties. The results are discussed in terms of occupancy Cu sites by Fe and redistribution of oxygen atoms.
Źródło:: Acta Physica Polonica A; 1997, 91, 2; 355-358
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 26.

Tytuł:: Heavy Fermion Superconductor Order Parameter in High Magnetic Field
Autorzy:: Kowalewski, L.
Wojciechowski, R.
Thomas, M.
Nogala, M.
Powiązania:: https://bibliotekanauki.pl/articles/1930573.pdf
Data publikacji:: 1994-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.Tx
74.60.-w
74.90.+n
Opis:: It is shown that, independently on either the nature and the strength of pairing, the orbital effects of a high magnetic field in heavy fermion superconductor change the form of both the effective pairing and the gap function.
Źródło:: Acta Physica Polonica A; 1994, 85, 2; 347-350
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 27.

Tytuł:: Superconducting Critical Temperature of Layered Mercurocuprate Family
Autorzy:: Kuzemsky, A. L.
Kuzemskaya, I. G.
Cheglokov, A. A.
Powiązania:: https://bibliotekanauki.pl/articles/2012917.pdf
Data publikacji:: 2000-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Nf
74.72.Bk
74.72.Gr
Opis:: We study the physics of the mercurocuprate family from the structural point of view. We present a phenomenological approach determining the critical temperatures for homologous series HgBa$\text{}_{2}$Ca$\text{}_{n-1}$Cu$\text{}_{n}$O$\text{}_{2n+2+δ}$ depending on the number of layers n. The model is based on the Lawrence- Doniach theory of layered superconductors modified for the case of inequivalent layers. The redistribution of charge was taken into account. This leads to observable nonmonotonic "bell"-shaped dependence of T$\text{}_{c}$(n) and provides a quantitative explanation of the experiments.
Źródło:: Acta Physica Polonica A; 2000, 97, 1; 241-244
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 28.

Tytuł:: Van Hove Singularity and Superconductivity in Disordered Sr$\text{}_{2}$RuO$\text{}_{4}$
Autorzy:: Litak, G.
Annett, J. F.
Györffy, B. L.
Powiązania:: https://bibliotekanauki.pl/articles/2012935.pdf
Data publikacji:: 2000-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.Dh
74.25.Dw
74.25.Fy
Opis:: On the basis of a simple model we analyse the influence of disorder on critical temperature T$\text{}_{c}$ in p-wave superconductors. The disorder is treated by means of the coherent potential approximation and we focus our attention on the effect of a van Hove singularity near Fermi energy E$\text{}_{F}$. For the appropriate values of its parameters our model reproduces the experimentally found behaviour of Sr$\text{}_{2}$ RuO$\text{}_{4}$.
Źródło:: Acta Physica Polonica A; 2000, 97, 1; 249-252
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 29.

Tytuł:: Superconducting density of states in B-doped diamond
Autorzy:: Onufriienko, O.
Samuely, T.
Zhang, G.
Vanacken, J.
Xu, Zheng
May, P.
Szabó, P.
Moshchalkov, V.
Samuely, P.
Powiązania:: https://bibliotekanauki.pl/articles/1052993.pdf
Data publikacji:: 2017-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.Wz
74.62.En
74.55.+v
Opis:: In the presented work, we investigated the superconducting boron doped diamond polycrystalline film prepared by chemical vapor deposition by means of scanning tunneling microscopy/spectroscopy. Differential conductance spectra measured at various temperatures were used to obtain the values of superconducting critical temperature and energy gap. Comparing various theoretical models fitted to the differential conductance spectra measured at 0.5 K suggests weak pair breaking. However, this cannot account for the high 2Δ/(k_{B}T_{C}) ratio, which therefore indicates strong coupling.
Źródło:: Acta Physica Polonica A; 2017, 131, 4; 1033-1035
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 30.

Tytuł:: Superconducting parameters of spinel CuRh₂S₄ under pressure
Autorzy:: Ito, M.
Taira, A.
Sonoda, K.
Powiązania:: https://bibliotekanauki.pl/articles/1054874.pdf
Data publikacji:: 2017-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.Dd
74.62.Fj
74.25.Bt
Opis:: We investigated the magnetic properties of chalcogenide-spinel superconductor CuRh₂S₄ under pressure and estimated the pressure dependence of the superconducting parameters. With increasing pressure, the superconducting transition temperature (T_{c}), thermodynamic critical field (H_{c}), upper critical field (H_{c2}), penetration depth (λ), and GL parameter (κ) increase. Meanwhile, the lower critical field (H_{c1}) is unchanged and the Ginzburg-Landau coherence length (ξ_{GL}) is reduced by pressurization. The increasing value of κ indicates enhanced characteristics of the type-II superconductor CuRh₂S₄.
Źródło:: Acta Physica Polonica A; 2017, 131, 6; 1450-1453
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 31.

Tytuł:: Pinning improvement of A15 applied superconducting materials
Autorzy:: Glowacki, B.
Powiązania:: https://bibliotekanauki.pl/articles/1062056.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Wx
74.25.Sv
74.25.Op
Opis:: Electron-phonon coupling is one of the most common interaction in superconducting materials ranging from Nb₃Sn, MgB₂, iron-based superconductors and high temperature cuprates such as YBa₂Cu₃O_{7-δ} and HgBa₂Ca₂Cu₃O_{8+δ}. However an importance of the electron-phonon coupling constant, λ_{ep}, should not be underestimated for characterisation of the electronic properties of superconducting materials, but it is important that the enhanced flux pinning mechanism can be hold responsible for the applicability of the A15 superconducting materials in emerging hydrogen cryomagnetic technology where temperature of the liquid H₂ can be as low as 14 K.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 531-536
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 32.

Tytuł:: Josephson Junctions Like Behavior in Superconducting Nb Films with Diluted Triangular Arrays of Antidots
Autorzy:: Mumtaz, M.
He, S.
Qiu, X.
Kamran, M.
Powiązania:: https://bibliotekanauki.pl/articles/1192515.pdf
Data publikacji:: 2015-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.F-
74.78.-w
74.81.Fa
Opis:: We present current versus voltage (I-V) measurement on superconducting Nb films with diluted triangular arrays (honeycomb and kagome) of antidots. Peaks and dips appearing in the derivative (dV/dI) of I-V curves showing the variation in the resistance is the indication of Josephson Junctions like weak-links in these systems. These observations also reveal the presence of mobile interstitial vortices in these lattices with regular pinning arrays. This behavior is predominant in honeycomb arrays due to large density of interstitial spaces in this system as compared that of to kagome lattice. This behavior can be tuned by temperature as well as external magnetic field but the tuning values of these parameters can be different for different symmetries of antidots.
Źródło:: Acta Physica Polonica A; 2015, 127, 4; 898-900
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 33.

Tytuł:: Modeling of Critical Current Density of Bulk High $T_c$ Superconductors
Autorzy:: Santosh, M.
Powiązania:: https://bibliotekanauki.pl/articles/1205410.pdf
Data publikacji:: 2014-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Sv
74.20.-z
Opis:: Magnetic field dependence of critical current density $(J_{c})$ of $ErBa_2Cu_3O_y$ thick film "Er-123" and melt textured $GdBa_2Cu_3O_y$ bulk "Gd-123" at liquid nitrogen temperature is reported. Gd-123 exhibits a usual peak effect at magnetic fields around 2 T, while $J_{c}$ of the Er-123 thick film continuously decreases with increasing field. The model of thermally activated flux motion was adopted to fit the critical current density of both Gd-123 and Er-123 materials. It was found that the critical current density of both types of the high $T_{c}$ materials could be modeled by the model of thermally activated flux motion utilizing a combination of two functions; one increasing and another one decreasing with field.
Źródło:: Acta Physica Polonica A; 2014, 126, 3; 808-810
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 34.

Tytuł:: Electromagnetic Response in Kinetic Energy Driven Superconductivity: the Meissner Effect
Autorzy:: Krzyzosiak, M.
Lan, Y.
Feng, S.
Jacak, L.
Gonczarek, R.
Powiązania:: https://bibliotekanauki.pl/articles/1536649.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.N-
74.20.Mn
Opis:: Electromagnetic response of cuprate superconductors is studied within the model of kinetic energy driven d-wave superconductivity by analyzing the Meissner effect. The kernel of the linear response function is found and employed to calculate the magnetic field penetration depth and the superfluid density of cuprate superconductors within the specular reflection model for a purely transverse vector potential. It is shown that the magnetic field penetration depth and the superfluid density depend linearly on temperature, except for a strong deviation from the linear characteristics at extremely low temperatures, which is attributed to nonlocal effects. The zero-temperature superfluid density is found to decrease linearly with decreasing doping concentration in the underdoped regime. The problem of gauge invariance in the theoretical description of the electromagnetic response is addressed, and an approximation which does not violate local charge conservation is proposed.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 283-288
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 35.

Tytuł:: On the Thermodynamic Critical Field for the $K_3C_{60}$ and $Rb_3C_{60}$ Fullerides
Autorzy:: Durajski, A.
Szczęśniak, R.
Powiązania:: https://bibliotekanauki.pl/articles/1371531.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: In the paper the temperature dependence of the thermodynamic critical field ($H_c$) for the alkali-metal-doped fullerides $K_3C_{60}$ and $Rb_3C_{60}$ has been considered. The numerical calculations have been conducted in the framework of the Migdal-Eliashberg formalism. It has been shown that the obtained numerical values of $H_c$ agree with the experimental data. Finally, the dimensionless ratio: $R_{H}$ ≡ $T_cC^{N}$ ($T_c$)/$H_c^{2}(0)$ has been calculated, where $T_c$ is the critical temperature and $C^{N}$ denotes the specific heat in the normal state. The theoretical analysis has proved that for the considered fullerides the parameter $R_{H}$ is beyond the BCS prediction. In particular: $R_{H}$=0.143 for $K_3C_{60}$, and $R_{H}$=0.145 for $Rb_3C_{60}$.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 342-343
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 36.

Tytuł:: Superconductivity in $Lu_xZr_{1-x}B_{12}$ Dodecaborides with Cage-Glass Crystal Structure
Autorzy:: Sluchanko, N.
Azarevich, A.
Bogach, A.
Gavrilkin, S.
Glushkov, V.
Demishev, S.
Mitsen, K.
Shitsevalova, N.
Filippov, V.
Gabani, S.
Flachbart, K.
Powiązania:: https://bibliotekanauki.pl/articles/1398292.pdf
Data publikacji:: 2017-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.-q
74.62.Bf
74.70.Ad
Opis:: We probed the evolution of the superconducting transition temperature $T_c$ and the normal state parameters of $Lu_xZr_{1-x}B_{12}$ solid solutions employing resistivity, heat capacity and magnetization measurements. In these studies of high-quality single crystals it was found that there are two types of samples with different magnetic characteristics. An unusually strong suppression of superconductivity in $Lu_xZr_{1-x}B_{12}$ with a rate $dT_c/dx=0.21 K/at.%$ of Lu was observed previously on the first "magnetic" set of crystals, and it was argued to be caused by the emergence of static spin polarization in the vicinity of non-magnetic lutetium ions. On the contrary, the second (current) set of "nonmagnetic" crystals demonstrates a conventional $T_c(x)$ dependence with a rate $dT_c/dx=0.12 K/at.%$ of Lu which is typical for BCS-type superconductors doped by nonmagnetic impurities. The reason for this difference is yet unclear. Moreover, the H-T phase diagram of the superconducting state of $Lu_xZr_{1-x}B_{12}$ (0 ≤ x ≤ 1) solid solutions has been deduced from magnetization measurements.
Źródło:: Acta Physica Polonica A; 2017, 131, 4; 1036-1038
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 37.

Tytuł:: Characteristics of the Eliashberg Formalism on the Example of High-Pressure Superconducting State in Phosphor
Autorzy:: Duda, A.
Szczęśniak, R.
Sowińska, M.
Domagalska, I.
Powiązania:: https://bibliotekanauki.pl/articles/1398651.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: The work describes the properties of the high-pressure superconducting state in phosphor: p∈ {20, 30, 40, 70} GPa. The calculations were performed in the framework of the Eliashberg formalism, which is the natural generalization of the BCS theory. The exceptional attention was paid to the accurate presentation of the used analysis scheme. With respect to the superconducting state in phosphor it was shown that the observed not-high values of the critical temperature ([T_{C}]_{p=30GPa}^\text{max}=8.45 K) result not only from the low values of the electron-phonon coupling constant, but also from the very strong depairing Coulomb interactions. Additionally the inconsiderable strong-coupling and retardation effects force the dimensionless ratios $R_{Δ}$, $R_{C}$, and $R_{H}$ - related to the critical temperature, the order parameter, the specific heat, and the thermodynamic critical field - to take the values close to the BCS predictions.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 649-654
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 38.

Tytuł:: Influence of the Granularity on the Transversal Resistance in Y_{0.55}Pr_{0.45}Ba_2Cu_3O_{7-δ} Superconductor
Autorzy:: da Luz, M.
dos Santos, C.
Machado, A.
Powiązania:: https://bibliotekanauki.pl/articles/1399293.pdf
Data publikacji:: 2013-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.-q
74.25.Fy
74.81.Bd
Opis:: This work reports longitudinal $(R_{XX})$ and transverse $(R_{XY})$ resistance as a function of temperature measured at low magnetic fields for $Y_{0.55}Pr_{0.45}Ba_2Cu_3O_{7-δ}$ polycrystalline sample. It is observed non-zero transverse resistance at zero applied magnetic field below superconducting transition. The comparison between $R_{XX} (T)$ and $R_{XY} (T)$ curves demonstrate unambiguously that the transverse resistance is related to the double resistive superconducting transition in granular superconductors. I-V curves indicate that the transport properties of the investigated sample are in agreement with the predictions of the two-fluid model.
Źródło:: Acta Physica Polonica A; 2013, 124, 4; 702-705
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 39.

Tytuł:: Impact of Strain on the Superconducting Properties of Strongly Underdoped $La_{2-x}Sr_xCuO_4$ Thin Films
Autorzy:: Zaytseva, I.
Cieplak, M.
Paszkowicz, W.
Abal'oshev, A.
Berkowski, M.
Powiązania:: https://bibliotekanauki.pl/articles/1431516.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.F-
74.62.En
74.78.-w
Opis:: Using pulsed laser deposition we have grown films of $La_{2-x}Sr_xCuO_4$ with x in close vicinity of the superconductor-insulator transition, x=0.051 and x=0.048, on $SrLaAlO_4$ substrates, and of different thickness d (from 25 nm to 250 nm). The X-ray diffraction shows that for each d the films grow with variable degree of compressive in-plane strain, with the largest strain achieved in thinnest films. The resistivity measurements show strong enhancement of superconductivity with increasing strain, so that the onset of superconductivity at temperature as high as 27 K is observed. With increasing strain the character of resistivity changes from the insulating to metallic.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 858-865
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 40.

Tytuł:: Temperature and Magnetic Field Dependences of Critical Current of Thallium-Based Superconducting Films
Autorzy:: Zalecki, R.
Kołodziejczyk, A.
Heiml, O.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/2046810.pdf
Data publikacji:: 2006-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Sv
74.78.Bz
74.72.Jt
Opis:: The critical current densities of three superconducting thallium-based films, prepared by screen printing, were measured as a function of temperature and applied magnetic field. The degradation of critical current densities was investigated for two different magnetic field orientations with respect to the sample plane - parallel and perpendicular.
Źródło:: Acta Physica Polonica A; 2006, 109, 4-5; 669-674
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 41.

Tytuł:: Magnetic Flux Density and Radial Distribution of Currents in HTSC Samples of Specific Shape Determined by Genetic Algorithm
Autorzy:: Piotrowski, K.
Gutowska, M. U.
Gutowski, M.
Powiązania:: https://bibliotekanauki.pl/articles/1964534.pdf
Data publikacji:: 1997-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.60.Jg
74.60.Ec
74.60.Ge
Opis:: Flux distribution in a Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8}$ superconductor sample, shaped as a thin disk with a hole in the center, and covered with a thin layer of magnetic garnet, was observed by means of magneto-optical Faraday effect. Applying external magnetic field perpendicularly to the sample plane with zero field cooling history, we were able to observe the flux trapped in superconductor, visible as concentric rings. Both directions of the trapped field were observed near the sample surface. Using the genetic algorithm we were able to determine the radial distribution of concentric currents in the sample under study.
Źródło:: Acta Physica Polonica A; 1997, 92, 1; 259-262
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 42.

Tytuł:: Ultrathin Niobium in the Si/Nb/Si Trilayers
Autorzy:: Zaytseva, I.
Abal'oshev, O.
Dłużewski, P.
Minikayev, R.
Cieplak, Marta
Zhu, L.
Chien, C.
Powiązania:: https://bibliotekanauki.pl/articles/1374193.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.78.-w
74.70.Ad
74.25.-q
Opis:: We study magnetotransport properties of the Si/Nb/Si trilayers, in which the thickness of niobium, d, changes from 1.1 nm to 50 nm, while the thickness of Si is fixed at 10 nm. The niobium films are amorphous for d < 4 nm, while in thicker films the alligned polycrystalline grains are formed. We observe that the Hall coefficient changes sign into negative in the films with d < 1.6 nm. We also find that in the ultrathin films the magnetic field induces a transition from the superconducting into a metallic phase with the resistance smaller than the normal-state resistance.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-140-A-144
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 43.

Tytuł:: Unconventional Superconductivity in Iron-Based Superconductors in a Three-Band Model
Autorzy:: Crivelli, D.
Ptok, A.
Powiązania:: https://bibliotekanauki.pl/articles/1374327.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Rp
74.70.Xa
74.25.Dw
Opis:: Iron-based superconductors exhibit features of systems where the Fulde-Ferrell-Larkin-Ovchinnikov phase, a superconducting state with non-zero total momentum of the Cooper pairs, is actively sought. Experimental and theoretical evidence points strongly to the Fulde-Ferrell-Larkin-Ovchinnikov phase in these materials above the Pauli limit. In this article we discuss the ground state of iron-based superconductors near the critical magnetic field and the full h-T phase diagram for pnictides in case of intra-band pairing, in a three-band model with $s_{±}$ symmetry.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-16-A-19
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 44.

Tytuł:: Influence of Iron Substitutions on the Transport Properties of $FeTe_{0.65}Se_{0.35}$ Single Crystals
Autorzy:: Bezusyy, V.
Gawryluk, D.
Malinowski, A.
Berkowski, M.
Cieplak, M.
Powiązania:: https://bibliotekanauki.pl/articles/1374765.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.F-
74.62.Dh
74.70.Xa
Opis:: We study the ab-plane resistivity and Hall effect in the single crystals of $Fe_{1-y}M_yTe_{0.65}Se_{0.35}$, where M = Co or Ni (0 ≤ y ≤ 0.21). In case of each dopant two types of crystals, with different crystalline quality, are prepared by Bridgman's method using different cooling rates, fast or slow. The impurities suppress the superconducting transition temperature, $T_c$, with different rates. $T_c$ reaches zero at markedly different impurity content: only 3 at.% of Ni, and about 14 at.% of Co. In addition, the suppression is somewhat dependent on the crystal cooling rate. The resistivity at the onset of superconductivity rises only weakly with the Co doping, while it increases 10 times faster for Ni. The Hall coefficient $R_{H}$ is positive for Co doping indicating that hole carriers dominate the transport. For Ni $R_{H}$ changes sign into negative at low temperatures for crystals with the Ni content exceeding 6 at.%. The implications of these results are discussed.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-76-A-79
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 45.

Tytuł:: Stability of Bilayer Superconductors against Thermomagnetic Avalanche
Autorzy:: Vasiliev, S.
Chumak, O.
Chabanenko, V.
Pérez-Rodríguez, F.
Nabiałek, A.
Powiązania:: https://bibliotekanauki.pl/articles/1374778.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Op
74.72.-h
74.25.Sv
Opis:: The problem of stability of bilayer type II superconductor with different critical current densities of inner part and coating was considered. The optimum thickness of surface layer enabling the maximal increase of the field of first flux jump was found. The field of instability for such bilayer structure was calculated for NbTi superconductor. An increase of the field of the first flux jump by about 60% has been found for optimal coating thickness.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-84-A-87
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 46.

Tytuł:: Kim-Type Critical State Models and Critical Currents of Thallium Based Superconductors
Autorzy:: Woch, W.
Zalecki, R.
Kołodziejczyk, A.
Heiml, O.
Sudra, H.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/1812280.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.Jt
74.25.Sv
74.25.Ha
Opis:: The two extended formulae in the power form of the Kim critical state model were used to fit the critical currents versus the dc applied magnetic field. Two samples of thallium based superconductors: the $(Tl_{0.6}Pb_{0.24}Bi_{0.16})$$(Sr_{0.9}Ba_{0.1})_2Ca_2Cu_3O_y$ film on single-crystalline lanthanum aluminate and the bulk $(Tl_{0.5}Pb_{0.5})Sr_2(Ca_{1.8}Gd_{0.2})Cu_2O_y$ were chosen to test the models. The formulae were compared to the percolation model described by the exponential expression. The first model fits the experimental data better for the thallium based film whereas the second approach is better for the thallium based bulk sample.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 99-106
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 47.

Tytuł:: Thermoelectric Power of $MgB_2$ Single Crystals Doped with Holes and Electrons
Autorzy:: Oganisian, K.
Rogacki, K.
Sulkowski, C.
Zhigadlo, N.
Katrych, S.
Karpinski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1812320.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Fy
74.70.Ad
74.62.Dh
Opis:: The thermoelectric power of $MgB_2$ single crystals, non-substituted, single-substituted with C, and co-substituted with C and Li, was investigated in the temperature range from 10 to 300 K. Both the in-plane $(S_ab)$ and the out-of-plane $(S_c)$ thermoelectric powers are positive for non-substituted crystals and both $S_{ab}$ and $S_c$ change a sign for crystals doped with electrons when C is substituted for B in the amount larger than 6 at.%. The substitution of C, which supplies electrons mainly into the σ band, reduces the thermoelectric power anisotropy, most likely by increasing the interband scattering. When Li is additionally co-substituted for Mg, $S_ab$ remains unchanged but $S_c$ increases substantially. The Li substitution donates holes into the π band rather than into the σ band and in this way modifies the π band properties, including the possible increase in the intraband scattering.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 191-195
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 48.

Tytuł:: Microwave Absorption Study on (Bi,Pb)-Sr-Ca-Cu-O Granular Superconductors
Autorzy:: Jurga, W.
Piekara-Sady, L.
Gazda, M.
Powiązania:: https://bibliotekanauki.pl/articles/1812335.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.-b
74.72.-h
74.45.+c
Opis:: (Bi,Pb)-Sr-Ca-Cu-O is considered as a system of 2201, 2212 and 2223 superconductors embedded in the insulating matrix. The size of the grains depends on the time of recrystallization. These types of ceramics exhibit a two-step transition to superconducting state. Because electrical properties depend among other on the Josephson coupling between grains, the magnetically modulated microwave absorption study was undertaken. Magnetically modulated microwave absorption signal was observed to arise just as temperature had been lowered below T₁. The shape of this signal was studied to recognize the second temperature T₂. Some strong oscillations appear on magnetically modulated microwave absorption at lower temperatures, which might be related to local percolation breakdown in superconducting network.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 253-256
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 49.

Tytuł:: Phase-Slip Processes in Superconducting Films: AC Josephson Effect and New Phase Transition
Autorzy:: Dmitriev, V.
Zolochevskii, I.
Bezuglyi, E.
Kondrashev, D.
Powiązania:: https://bibliotekanauki.pl/articles/1812339.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Fy
74.25.Nf
74.50.+r
Opis:: The resistive direct current state in wide thin superconducting films as the phase transition from superconducting to normal state is investigated in the absence of external magnetic field. We showed that the states of a wide film with increasing transport current appear in the following order: the superconducting state; the resistive vortex state; the critical state; the new vortex-free resistive state with phase-slip lines; the normal state. We detected the Shapiro current steps on the current-voltage characteristic of the wide film, which arise due to interaction of intrinsic Josephson radiation of phase-slip lines with external microwave irradiation.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 257-261
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 50.

Tytuł:: Easy Vortex Motion in an Artificial Channel of $YBa_2Cu_3O_{7-δ}$ Superconducting Films
Autorzy:: Jukna, A.
Barboy, I.
Jung, G.
Abrutis, A.
Li, X.
Wang, D.
Sobolewski, R.
Powiązania:: https://bibliotekanauki.pl/articles/1813381.pdf
Data publikacji:: 2008-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Sv
74.25.Qt
74.78.Bz
Opis:: Quasi-Josephson effect produced by a coherent vortex motion in the horizontal part of the laser-performedΠ-shaped channel of a $YBa_2Cu_3O_{7-δ}$ superconducting bridge was investigated by means of electric transport measurements. We observed that in our structures, in a limited range of temperatures and bias currents, the vortices were confined in the channel only and moved coherently with the velocity of $3×10^4$ m/s. The corresponding current-voltage characteristics of the bridge exhibited Josephson-like voltage steps with the amplitude dependent on temperature, but independent of the bias current.
Źródło:: Acta Physica Polonica A; 2008, 113, 3; 959-962
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 51.

Tytuł:: Studies on Isotope Shift Exponent and Pressure Coefficient for Extended Superconductors within BCS Formalism
Autorzy:: Banerjee, B.
Roy, S.
Powiązania:: https://bibliotekanauki.pl/articles/1808029.pdf
Data publikacji:: 2009-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.+f
74.25.Bt
74.25.Ha
Opis:: A tight-binding model comprising a hopping and an attractive interaction term was considered for high temperature superconductors. Explicit calculations on the effects of isotopic substitution of atoms and application of pressure on the transition temperatures were made in this work. Exact analytical expressions for the isotope-shift exponent (α) and pressure coefficient $(γ_P)$ of transition temperature $(T_C)$ considering the isotopic mass and pressure dependence of the hopping and attractive interaction strengths from a minimal model describing superconductivity were obtained. Theoretical predictions for α and $γ_P$ with proper choice of parameters are found to be qualitatively consistent with the results of the experiments of high $T_C$ oxides. The results depend on the band dispersion chosen.
Źródło:: Acta Physica Polonica A; 2009, 115, 5; 914-919
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 52.

Tytuł:: Pressure Dependence of the Thermodynamic Critical Field in Francium
Autorzy:: Pach, P.
Szczęśniak, R.
Durajski, A.
Powiązania:: https://bibliotekanauki.pl/articles/1384843.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: In the paper, the values of the thermodynamic critical field $(H_{C})$ for francium have been calculated. It has been assumed the wide range of the pressure: p∈ ⟨7.2; 14⟩ GPa. The analysis has been performed in the framework of the strong-coupling formalism. It has been predicted that the value of the ratio $H_{C}(0)$/√ρ(0) increases with the increasing pressure from 3.08 meV to 5.84 meV, where ρ(0) denotes the electron density of states at the Fermi level. The dimensionless parameter $T_{C}C^{N}(T_{C})$/$H²_{C}(0)$ is smaller than in the BCS theory and decreases with pressure from 0.150 to 0.141. The symbol $T_{C}$ represents the critical temperature and $C^{N}$ is the specific heat for the normal state.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 231-233
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 53.

Tytuł:: Characterization of Novel High-Pressure Close-Packed Superconducting Phase of Boron
Autorzy:: Szczęśniak, D.
Szczęśniak, R.
Powiązania:: https://bibliotekanauki.pl/articles/1385110.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Bt
74.62.Fj
74.20.Fg
Opis:: We report study on the thermodynamic properties of the novel high-pressure superconducting phase of boron with hexagonal P6₃/mcm structure. Our analysis is conducted at the pressure of p=400 GPa, which is motivated by the highest value of the superconducting transition temperature $(T_{C})$ observed previously under such conditions for the P6₃/mcm boron. Our investigations of the thermodynamic properties are performed within the Eliashberg formalism, due to the strong-coupling character of the considered material. In particular, we calculate the thermodynamic properties of the superconducting state which allows us to determine the values of the characteristic dimensionless parameters; the zero-temperature energy gap to the critical temperature, the ratio of the specific heats, as well as the ratio connected with the zero-temperature thermodynamic critical field.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 254-256
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 54.

Tytuł:: Magnetoresistance of Si/Nb/Si Trilayers
Autorzy:: Zaytseva, I.
Cieplak, M.
Abal'oshev, A.
Dluzewski, P.
Grabecki, G.
Plesiewicz, W.
Zhu, L.
Chien, C.
Powiązania:: https://bibliotekanauki.pl/articles/1537220.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.-c
74.25.F-
74.25.Ha
74.62.En
Opis:: We study the superconductor-insulator transition in Si/Nb/Si trilayers, in which the thickness of Si is fixed at 10 nm, and the nominal thickness of Nb changes in the range between d = 20 nm down to d = 0.3 nm. The transmission electron microscopy indicates the formation of the mixed Nb-Si layer for small d. Both the thickness-induced, and the magnetic-field induced superconductor-insulator transition is observed. The crossing point of the isotherms at the critical field $B_{c}$ decreases with decreasing d, and it is T-independent at temperatures below 300 mK. At larger fields the weak peak in magnetoresistance appears in some of the films.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 406-408
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 55.

Tytuł:: Thermal Fluctuations of $(Tl_{0.5}Pb_{0.5})Sr_2(Ca_{0.9}Gd_{0.1})Cu_2O_{z}$ Bulk Superconductor
Autorzy:: Woch, W.
Chrobak, M.
Kołodziejczyk, A.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/1426876.pdf
Data publikacji:: 2012-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.40.-n
74.20.De
74.25.Ha
Opis:: We report on the critical fluctuations from the magnetoresistance measurements in polycrystalline $(Tl_{0.5}Pb_{0.5})Sr_2(Ca_{0.9}Gd_{0.1})Cu_2O_{z}$ superconductor. The critical exponents have been calculated above the critical temperature $T_{c}$ as well as in the temperatures interval close to the zero resistance critical temperature. Above $T_{c}$ only Gaussian fluctuations have been observed in a three-dimensional fluctuating system. Additionally, far above $T_{c}$ the applied magnetic field induces the crossover from 3D to 2D fluctuating system. At the temperatures range close to the zero critical temperature the properties of the weak links are dominating and the fluctuating phase in each grain becomes long-range ordered as a consequence of the activation of weak links between grains.
Źródło:: Acta Physica Polonica A; 2012, 121, 5-6; 1059-1062
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 56.

Tytuł:: Study of Resistive Superconducting Transition of Thallium Based Superconductors
Autorzy:: Woch, W.
Zalecki, R.
Chrobak, M.
Kołodziejczyk, A.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/1431253.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.40.n
74.20.De
74.25.Ha
Opis:: A width and shape of resistive transition as well as thermal fluctuations of the thallium based superconductors were analyzed theoretically. The applied magnetic field widens the resistive transition according to the following formula: $ΔT=CH^{m}+ΔT_{0}$. The exponent m fluctuates around 2/3 and depends on vortex structure and strength of the pinning force. The shape of the resistive transition was fitted by two models: the first one based on Ambegaokar-Halperin theory and the other one based on Anderson-Kim theory expressed by the exponential formula. Critical fluctuations were analyzed on the basis of magnetoresistance measurements results. The critical exponents have been calculated above the critical temperature $T_{c}$ as well as for temperatures close to the zero resistance critical temperature.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 789-795
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 57.

Tytuł:: Doping Effects of Co, Ni, and Cu in $FeTe_{0.65}Se_{0.35}$ Single Crystals
Autorzy:: Bezusyy, V.
Gawryluk, D.
Berkowski, M.
Cieplak, M.
Powiązania:: https://bibliotekanauki.pl/articles/1431291.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.F-
74.25.Op
74.62.Dh
74.70.Xa
Opis:: The resistivity, magnetoresistance, and magnetic susceptibility are measured in single crystals of $FeTe_{0.65}Se_{0.35}$ with Cu, Ni, and Co substitutions for Fe. The crystals are grown by Bridgman's method. The resistivity measurements show that superconductivity disappears with the rate which correlates with the nominal valence of the impurity. From magnetoresistance we evaluate doping effect on the basic superconducting parameters, such as upper critical field and coherence length. We find indications that doping leads to two component superconducting behavior, possibly because of local charge depression around impurities.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 816-819
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 58.

Tytuł:: Resistance and AC Susceptibility of YBCO 1:2:3 Films on Silver Substrates
Autorzy:: Zalecki, R.
Woch, W.
Chrobak, M.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1431494.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.F
74.25.Ha
74.25.Sv
Opis:: The $YBa_{2}Cu_{3}O_{δ}$ films were obtained directly on the polished silver substrates by the sedimentation process. Thickness of these films is of the order of several tens micrometers. The temperature dependences of the resistance and the AC susceptibility of the films were measured and analyzed. The critical temperatures of these specimens vary from 89 K to 91 K and they do not depend on the annealing temperatures. The critical currents were calculated from AC susceptibility measurements using the Bean's model.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 850-853
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 59.

Tytuł:: Penetration Depth of $Tl_2Ba_2Ca_2Cu_3O_y$ and $Tl_{0.58}Pb_{0.4}Sr_{1.6}Ba_{0.4}Ca_2Cu_3O_y$ Bulk Superconductors
Autorzy:: Zalecki, R.
Woch, W.
Kołodziejczyk, A.
Konig, W.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/1374160.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Ha
74.25.Wx
74.20.De
Opis:: The penetration depths of bulk $Tl_2Ba_2Ca_2Cu_3O_y$ and $Tl_{0.58}Pb_{0.4}Sr_{1.6}Ba_{0.4}Ca_2Cu_3O_y$ superconductors with the critical temperatures 112 K and 114 K, respectively, were determined from the AC susceptibility measurements. When the samples are in the Meissner state, the dispersive components of AC susceptibility as well as their temperature dependences reflect the changes of the penetration depths at various temperatures. In these bulk ceramic superconductors the penetration depths are of the order of few μm and they are comparable to the grains sizes in the ceramics.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-133-A-136
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 60.

Tytuł:: Thermal Fluctuations in YBCO Thin Film on MgO Substrate
Autorzy:: Chrobak, M.
Woch, W.
Szwachta, G.
Zalecki, R.
Gondek, Ł.
Kołodziejczyk, A.
Kusiński, J.
Powiązania:: https://bibliotekanauki.pl/articles/1374789.pdf
Data publikacji:: 2014-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.78.-w
74.40.-n
74.62.-c
Opis:: The c-axis orientation $YBa_2Cu_3O_δ$ thin film was prepared directly on MgO substrate by the pulse laser deposition. The thickness of the film was 170 nm. The superconducting critical temperature was $T_{c50%}$=89 K and the width of superconducting transition was Δ T= 1.6 K. Temperature dependence of the critical current of the film was obtained from the temperature dependences of the imaginary part of the AC susceptibility using the Bean model. The critical current density was $J_{c}$=1.2×$10^7$ A/$cm^{2}$ at 77 K in the self field. The critical exponents were calculated for several values of the DC applied magnetic field using the temperature dependences of magnetoresistivity. The thermal fluctuations in vicinity of the critical temperature were analysed.
Źródło:: Acta Physica Polonica A; 2014, 126, 4a; A-88-A-91
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 61.

Tytuł:: Penetration Depth of Magnetic Field into YBa₂Cu₃Oₓ Film on Polycrystalline Ag Substrate
Autorzy:: Zalecki, R.
Woch, W.
Chrobak, M.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1385218.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Ha
74.25.Wx
74.20.De
Opis:: The magnetic field penetration depth into YBa₂Cu₃Oₓ film on polycrystalline Ag substrate with the critical temperature of 90.4 K was determined from the AC susceptibility measurements. The 95 μm thick YBCO film was deposited directly on Ag substrate by the sedimentation process. When the sample is in the Meissner state, the dispersive component of the AC susceptibility as well as its temperature dependence reflects the changes of the penetration depth with the temperature. The penetration depth of this film is found to be 5.4 μm.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 272-274
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 62.

Tytuł:: Thermal Fluctuations of Bismuth Based 1G Tape
Autorzy:: Chrobak, M.
Woch, W.
Zalecki, R.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1385435.pdf
Data publikacji:: 2015-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.78.-w
74.40.-n
74.62.-c
Opis:: The thermal fluctuations of bismuth based commercial 1G tape were studied near the critical temperature $T_{c}$=110.2 K. The detailed analysis of the temperature dependence of resistivity measurements was made in the temperature region from the zero resistance critical temperature up to 300 K. The thermal fluctuations of conductivity were analysed using the Aslamazov-Larkin microscopic approach and the critical exponents were calculated close to the transition temperature.
Źródło:: Acta Physica Polonica A; 2015, 127, 2; 306-308
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 63.

Tytuł:: Vortex Dynamics in Ferromagnetic/Superconducting Bilayers
Autorzy:: Cieplak, M.
Adamus, Z.
Kończykowski, M.
Zhu, L.
Chien, C.
Powiązania:: https://bibliotekanauki.pl/articles/1812264.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Qt
74.78.Db
74.78.Fk
Opis:: The dependence of vortex dynamics on the geometry of magnetic domain pattern is studied in the superconducting/ferromagnetic bilayers, in which niobium is a superconductor, and Co/Pt multilayer with perpendicular magnetic anisotropy serves as a ferrromagnetic layer. Magnetic domain patterns with different density of domains per surface area and different domain size, w, are obtained for Co/Pt with different thickness of Pt. The dense patterns of domains with the size comparable to the magnetic penetration depth (w≥λ) produce large vortex pinning and smooth vortex penetration, while less dense patterns with larger domains (w ≫ λ) enhance pinning less effectively and result in flux jumps during flux motion.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 23-28
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 64.

Tytuł:: Superconducting Pinning by Magnetic Domains in a Ferromagnet-Superconductor Bilayer
Autorzy:: Cieplak, M. Z.
Adamus, Z.
Konczykowski, M.
Chen, X. M.
Byczuk, A.
Abal'oshev, A.
Sang, Hai.
Chien, C. L.
Powiązania:: https://bibliotekanauki.pl/articles/2041450.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Qt
74.78.Db
74.78.Fk
Opis:: The local flux profile and the critical current are studied using an array of Hall sensors in a ferromagnetic-superconducting bilayer which consists of niobium film covering ferromagnetic Co/Pt multilayer with perpendicular magnetic anisotropy. The results indicate about threefold enhancement of the flux pinning in niobium layer caused by the isolated magnetic domains which are created during the magnetization reversal of the Co/Pt multilayer. The geometrical barrier is absent, and the critical current is strongly peaked in close vicinity to the sample center, suggesting that the critical state differs from that predicted by the Bean model.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 693-698
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 65.

Tytuł:: Oxygen Deficient YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$: Two Superconducting Phases
Autorzy:: Stankowski, J.
Ślązak, A.
Kempiński, W.
Andrzejewski, B.
Reichel, B.
Plesch, G.
Powiązania:: https://bibliotekanauki.pl/articles/2037166.pdf
Data publikacji:: 2004-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.62.Bf
74.62.-c
74.25.Nf
Opis:: A set of oxygen deficient powder and granular samples of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ ceramics was studied by means of thermogravimetric and magnetically modulated microwave absorption methods. Especially the last method has turned out to be a powerful method, which was used to determine the dependence of critical temperature T$\text{}_{c}$ on the oxygen parameterδ. Using these methods it has been shown that the removing of oxygen evokes the inhomogeneous oxygen distribution in the samples and a change in carrier concentration till to the loss of superconducting properties. A superconducting phase with T$\text{}_{c}$=60 K, which occurs in oxygen deficient YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ sample, is an unstable phase.
Źródło:: Acta Physica Polonica A; 2004, 105, 3; 287-294
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 66.

Tytuł:: Magneto-Optics of Spontaneous and Field Induced Vortices in Twinned YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$/La$\text{}_{1-x}$Sr$\text{}_{x}$MnO$\text{}_{3}$ Bilayers
Autorzy:: Gerbaldo, R.
Ghigo, G.
Gozzelino, L.
Laviano, F.
Mezzetti, E.
Minetti, B.
Przysłupski, P.
Tsarou, A.
Wiśniewski, A.
Powiązania:: https://bibliotekanauki.pl/articles/2047210.pdf
Data publikacji:: 2007-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Qt
74.78.Db
74.78.Fk
Opis:: The electromagnetic coupling between the magnetic and the superconducting layers in perovskite heterostructures is investigated by means of the magneto-optical technique. The quantitative imaging of the magnetic field distribution allows the high-resolution reconstruction of local supercurrent density. Two phenomena arising from the coupling between manganite layer and the YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ superconducting film deposited on top are addressed, i.e., the local effects of the electronic coupling between the compounds and the interaction between the manganite magnetic moments and the vortices in the superconductor. The first issue can be quantified in terms of the local superfluid density depression/enhancement in correspondence to the underlying magnetic structure, both domains and domain walls (in dependence on the orientation and sign of the local magnetization) and of the spontaneous, macroscopic screening current loops generated by the manganite domain walls. The interaction between the local manganite magnetization and the superconducting vortices is also influenced by structural defects because they modulate the magnetic pattern of the manganite. Different channelling phenomena in correspondence to the natural twin boundaries of the substrate, but locally magnetized by pinned domain walls of the manganite on their locations, are recognized.
Źródło:: Acta Physica Polonica A; 2007, 111, 1; 47-55
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 67.

Tytuł:: Flux Penetration in a Ferromagnetic/Superconducting Bilayer
Autorzy:: Adamus, Z.
Cieplak, M. Z.
Abal'oshev, A.
Kończykowski, M.
Cheng, X. M.
Zhu, L. Y.
Chien, C. L.
Powiązania:: https://bibliotekanauki.pl/articles/2047227.pdf
Data publikacji:: 2007-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Qt
74.78.Db
74.78.Fk
Opis:: An array of miniature Hall sensors is used to study the magnetic flux penetration in a ferromagnetic/superconducting bilayer consisting of Nb as a superconducting layer and Co/Pt multilayer with perpendicular magnetic anisotropy as a ferromagnetic layer, separated by an amorphous Si layer to avoid the proximity effect. It is found that the magnetic domains in the ferromagnetic layer create a large edge barrier in the superconducting layer which delays flux penetration. The smooth flux profiles observed in the absence of magnetic pinning change into terraced profiles in the presence of domains.
Źródło:: Acta Physica Polonica A; 2007, 111, 1; 95-98
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 68.

Tytuł:: Universal Critical Quantum Properties of Cuprate Superconductors
Autorzy:: Schneider, T.
Powiązania:: https://bibliotekanauki.pl/articles/1953179.pdf
Data publikacji:: 1997-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.-c
74.72.-h
74.62.Dh
74.25.-q
Opis:: Using the scaling theory of quantum critical phenomena we explore the occurrence of universal critical behavior at the insulator-to-superconductor and superconductor-to-normal state transitions at zero temperature. Experimentally, these phase transitions are driven by doping and correspond to critical end points of the phase transition line in the temperature-hole concentration plane. Provided that the order parameter is a complex scalar in two dimensions, and that the London relation between superfluid number density and magnetic penetration depth holds, the scaling theory predicts universal behavior close to the insulator-to-superconductor transition. In particular, transition temperature and zero temperature penetration depth are universally related and the sheet resistance adopts a universal value. These predictions agree remarkably well with available experimental data and provide useful constraints for a microscopic theory.
Źródło:: Acta Physica Polonica A; 1997, 91, 1; 203-212
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 69.

Tytuł:: On the Magnetic Penetration Depth in Superconducting Ultrathin Lead Films
Autorzy:: Durajski, A.
Szczęśniak, R.
Powiązania:: https://bibliotekanauki.pl/articles/1032804.pdf
Data publikacji:: 2017-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: In the present paper, we report a theoretical study of the magnetic London penetration depth in ultrathin Pb films consisting of five to ten monolayers. Our calculations were performed within the framework of the strong-coupling approach. We observed that for thin films, the thermodynamic parameter exhibits an oscillatory behaviour connected with a quantum size effect. Moreover, we proved that the London penetration depth of Pb films cannot be correctly described using the Bardeen-Cooper-Schrieffer theory of superconductivity due to the strong-coupling and retardation effects. The Eliashberg theory, used in this paper, goes beyond the BCS theory to include these effects which allows to describe the superconducting state on the quantitative level.
Źródło:: Acta Physica Polonica A; 2017, 131, 4; 1051-1053
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 70.

Tytuł:: Electron Behaviour of $(Nd_{0.33}Eu_{0.2}Gd_{0.47})Ba_2Cu_3O_{y}$ Studied by Infrared Measurements
Autorzy:: Rameš, M.
Železný, V.
Phuoc, V.
Gervais, F.
Wolf, T.
Jirsa, M.
Powiązania:: https://bibliotekanauki.pl/articles/1534787.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Gz
74.20.Mn
74.25.Kc
Opis:: Optical properties of a are $(Nd_{0.33}Eu_{0.2}Gd_{0.47})Ba_2$ $Cu_3O_y$ (NEG-123) single crystal interpreted in terms of the extended Drude model.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 938-939
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 71.

Tytuł:: Reversible Magnetization of Melt-Processed NEG-123 Superconductor
Autorzy:: Jirsa, M.
Rameš, M.
Muralidhar, M.
Kacmarcik, J.
Marcenat, Ch.
Powiązania:: https://bibliotekanauki.pl/articles/1535270.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Bt
74.25.Op
Opis:: Specific heat of superconducting electrons was measured in a melt-processed $(Nd_{0.33}Eu_{0.38}Gd_{0.28})Ba_2Cu_3O_{y}$ superconductor (NEG-123) with 5 mol% of Gd-211, 1 wt% Ag, and 0.035 mol% of Zn. The thermodynamic characteristics of this compound are still not well known. From calorimetric measurements the reversible magnetization, critical fields, penetration depth, and coherence length were deduced. In the vicinity of $T_{c}$, the reversible magnetic moment was additionally measured by means of SQUID.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1022-1023
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 72.

Tytuł:: Critical Current Density and Microstructure of $NdBa_2Cu_3O_7$ Single Crystal
Autorzy:: Diko, P.
Zmorayová, K.
Šefčiková, M.
Antal, V.
Kováč, J.
Yao, X.
Powiązania:: https://bibliotekanauki.pl/articles/1535339.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Sv
74.62.Bf
Opis:: The top-seeded solution growth method was used to grow NdBCOss single crystals in air. The microstructure of the samples has shown that the oxygenation crack structure developed in the single crystals. The intrinsic critical current density was estimated to be at least twice higher than the value of volume critical current density determined from the magnetization measurements.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1028-1030
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 73.

Tytuł:: The Thermodynamic Critical Field οf $YNi_2B_2C$ Superconductor
Autorzy:: Jarosik, M.
Szczęśniak, R.
Szczęśniak, D.
Powiązania:: https://bibliotekanauki.pl/articles/1535384.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.25.Ha
Opis:: In the presented work the dependence of the thermodynamic critical field $(H_{C})$ on the temperature for the $YNi_2B_2C$ superconductor was determined in the framework of the Eliashberg formalism. The numerical calculations were conducted with the use of the modified transport Eliashberg function. It has been stated that the normalized field function $H_{C}(T)//H_{C}(0)$ correctly reproduces the experimental data.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1031-1033
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 74.

Tytuł:: Strong-Coupling Features in $YB_6$ and $ZrB_{12}$ Studied by Point-Contact Spectroscopy
Autorzy:: Girovský, J.
Szabó, P.
Mori, T.
Samuely, P.
Powiązania:: https://bibliotekanauki.pl/articles/1535414.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.50.+r
74.70.Ad
74.62.Dh
Opis:: Point-contact spectroscopy studies of the superconducting energy gap and the electron-phonon coupling mechanism are performed on the boron rich $YB_6$ and $ZrB_{12}$ single crystals. The obtained values of the superconducting energy gaps suggest the strong coupling with 2 Δ/$k_{B}T_{c}$≈ 4.2 for $YB_6$ and 2 Δ/$k_{B}T_{c}$≈ 4.15 for $ZrB_{12}$. We have observed the dominant soft phonon modes mediating superconductivity in the both samples at energy ≈ 8 meV for $YB_6$ and ≈ 11 meV in $ZrB_{12}$, respectively.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1042-1044
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 75.

Tytuł:: Point Contact Spectroscopy Measurements of $Ba(Fe_{0.96}Co_{0.04})_2As_2$ Single Crystals
Autorzy:: Szabó, P.
Girovský, J.
Pribulová, Z.
Samuely, T.
Bud'ko, S.
Canfield, P.
Samuely, P.
Powiązania:: https://bibliotekanauki.pl/articles/1535447.pdf
Data publikacji:: 2010-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.50.+r
74.70.Ad
74.62.Dh
Opis:: Point contact spectroscopy results are presented on the electron underdoped $Ba(Fe_{0.96}Co_{0.04})_2As_2$ single crystals. Two superconducting energy gaps with coupling values 2 $Δ_1$ ∿ $kT_{c}$ ≈ 2.55 and 2 $Δ_2$ ∿ $kT_{c}$ ≈ 11 at $T_{c}$ = 15.5 K have been observed in the point contact spectra. The temperature dependence of the normal state background of the point contact spectra observed between $T_{c}$ and $T_{N}$ indicates antiferromagnetic origin of the V-shaped minimum at zero bias.
Źródło:: Acta Physica Polonica A; 2010, 118, 5; 1045-1046
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 76.

Tytuł:: On Realization of the Bose-Einstein Condensates and Quantum Superfluids
Autorzy:: Domański, T.
Powiązania:: https://bibliotekanauki.pl/articles/1536541.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.20.Mn
74.40.-n
Opis:: The purpose of this work is twofold. In the first part we describe superfluidity/superconductivity as an emergent phenomenon resulting from two-body correlations in presence of the Bose-Einstein condensation of particles. We briefly discuss the underlying mechanism for bosons as well as fermion pairs and illustrate various realizations of superfluidity emphasizing the recent examples. In the second part we study the glassy liquid of incoherent pairs which might exist above the transition temperature $T_{c}$ in the underdoped regime of cuprate superconductors. In particular, we explore the angular variation of pseudogap within two-dimensional version of the boson-fermion model using for a quantitative analysis the projective method. We find that above $T_{c}$ the pseudogap closes first near the nodal areas restoring there pieces (arcs) of the Fermi surface whereas remaining parts of the large Fermi surface around the antinodal points are still absent due to incoherent pairs. Upon increasing temperature the length of the Fermi arcs enlarges because the superconducting correlations are gradually suppressed. An intriguing death of Fermi surface can thus be closely related to the Bogoliubov quasiparticles whose existence in the pseudogap state has been predicted by us and confirmed recently by the angle resolved photoemission spectroscopy measurements on $Bi_2Sr_2CaCu_2O_8$ and $La_{1.895}Sr_{0.105}CuO_4$ compounds.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 204-211
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 77.

Tytuł:: Critical Currents, Magnetization and Microwave Absorption of $(Tl_{0.5}Pb_{0.5})Sr_2(Ca_{0.8}Gd_{0.2})Cu_2O_{z}$ Superconductor
Autorzy:: Woch, W.
Niewolski, J.
Tokarz, W.
Kołodziejczyk, A.
Sudra, H.
Gritzner, G.
Powiązania:: https://bibliotekanauki.pl/articles/1536936.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.81.Bd
74.25.Sv
74.81.Fa
Opis:: The bulk ($Tl_{0.5}Pb_{0.5})Sr_2(Ca_{1 - x}Gd_{x})Cu_2O_{z}$ superconductors with x = 0.1, 0.2 and 0.3 have unique and very interesting magnetic and electrical properties. In this paper we focused our attention on the superconductor with gadolinium content x = 0.2. We measured the magnetic field dependences of the transport critical currents, the microwave absorption as well as the magnetization for different temperatures. The critical temperature of this sample is $T_c$ = 105.3 ± 0.2 K and the transition width Δ $T_{90% - 10%}$ = 3.6 ± 0.2 K. The critical current of this superconductor is $J_c$ = 1 820 ± 10 A/$cm^2$ at 77 K. The data were analyzed within the frame of the Bean and Kim models as well as the percolation model.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 319-322
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 78.

Tytuł:: Analysis of Resistive Superconducting Transition of a $(Tl_{0.6}Pb_{0.24}Bi_{0.16})(Ba_{0.1}Sr_{0.9})_2Ca_2Cu_3O_{y}$ Film
Autorzy:: Woch, W.
Chrobak, M.
Kołodziejczyk, A.
Powiązania:: https://bibliotekanauki.pl/articles/1537158.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Uv
74.25.Sv
74.20.De
Opis:: In this paper we analyze the resistive transition as a function of both the temperature and the dc applied magnetic field. We use the two models: first, based on the Ambegaokar and Halperin theory that describes the resistive transitions by the modified Bessel function and second, based on the Anderson and Kim theory represented by the exponential formula. The fits of the models to experimental results show that the freezing into superconducting vortex-glass phase takes place at the same temperature that does not practically depend on the applied magnetic field.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 389-392
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 79.

Tytuł:: Inhomogeneous Magnetic Field Penetration in Superconducting Niobium Films
Autorzy:: Abal'osheva, I.
Abal'oshev, A.
Cieplak, M.
Zhu, L.
Chien, C.
Powiązania:: https://bibliotekanauki.pl/articles/1537190.pdf
Data publikacji:: 2010-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Uv
74.70.Ad
Opis:: The peculiarities of magnetic field penetration in the form of fingering or dendritic instabilities are studied by magneto-optical technique in the niobium films of different thickness. It is observed that the reduction of Nb film thickness reduces the threshold field for instabilities, in agreement with the theoretical predictions. In addition, it is shown that the silver overlayer deposited on the top of Nb film leads also to the enhancement of instabilities, in marked contrast to the effect of gold or aluminum overlayers, which are known to suppress instabilities.
Źródło:: Acta Physica Polonica A; 2010, 118, 2; 396-398
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 80.

Tytuł:: Magnetization Studies of $Cu_{0.058}TiSe_{2}$ Near a Quantum Critical Point
Autorzy:: Husaníková, P.
Cambel, V.
Fedor, J.
Šoltýs, J.
Karapetrov, G.
Powiązania:: https://bibliotekanauki.pl/articles/1371487.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Ha
74.25.Op
74.20.De
Opis:: We study superconducting properties of highly underdoped $Cu_{0.058}TiSe_{2}$ single crystal by means of bulk magnetization measurements. We extract the upper critical field, $H_{c2}$, for magnetic field applied parallel, as well as perpendicular to the sample planes. Obtained values, $H_{c2}^{ab}(0)$=1.03 T and $H_{c2}^c(0)$=0.54 T, define a moderate anisotropy of the upper critical fields of 1.90. From the upper and lower critical fields we extract the Ginzburg-Landau parameters $κ_{ab}(0)$=26.3, and $κ_c(0)$=12.6 that classify $Cu_{0.058}TiSe_{2}$ as an extreme type II superconductor.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 336-337
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 81.

Tytuł:: Superconductivity Near Transition to Insulating State in MoC Ultrathin Films Studied by Subkelvin STM
Autorzy:: Szabó, P.
Neilinger, P.
Trgala, M.
Grajcar, M.
Samuely, P.
Powiązania:: https://bibliotekanauki.pl/articles/1372334.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.50.+r
74.78.-w
74.81.-g
Opis:: We study the homogeneously disordered MoC thin films with thicknesses of 10 and 5 nm and the superconducting transition temperatures near 6 and 4 K, significantly decreased as compared to the bulk $T_{c}$=8.32 K due to a disorder. The scanning tunnelling spectroscopy reveals in the thicker sample a BCS superconducting energy gap Δ with a broadening parameter Γ equal to about 10 per cent of Δ. Remarkably, Γ increases with temperature. The thinner, more disordered sample shows a gapped superconducting density of states but without any coherence peaks at the gap edge, which could not be approximated by the BCS DOS. Moreover, the reduced DOS around the Fermi level persists above the resistive transition temperature reminding the pseudo-gap known from high-$T_{c}$ cuprates.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 368-369
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 82.

Tytuł:: Phonon Drag and Carrier Diffusion Contributions in Thermoelectric Power of $M_3C_{60}$ (M = K, Rb) Fullerides
Autorzy:: Varshney, D.
Singh, N.
Powiązania:: https://bibliotekanauki.pl/articles/1400154.pdf
Data publikacji:: 2013-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.Wz
74.25.fg
74.25.Kc
Opis:: The thermoelectric power (S) of $M_3C_{60}$ (M = K, Rb) alkali intercalated fullerides is theoretically investigated by considering the Mott expression within parabolic band approximation to reveal the electron diffusive thermoelectric power $(S_{c}^{diff})$. We follow the Fermi energy as electron parameter and $S_{c}^{diff}$ discerned linear temperature dependence. S infers a change in slope above transition temperature and becomes almost linear above 70 K for $M_3C_{60}$ alkali intercalated fullerides. As a next step, the phonon drag thermoelectric power $(S_{ph}^\text{drag})$ is computed within relaxation time approximation when thermoelectric power is limited by scattering of phonons from defects, grain boundaries, phonons and electrons as carriers. It is noticed that the $S_{ph}^\text{drag}$ of $K_3C_{60}$ is anomalous and it is an artifact of strong phonon-electron and -phonon scattering mechanism. The thermoelectric power within relaxation time approximation has been taken into account ignoring a possible energy dependence of the scattering rates. Behaviour of S(T) is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between carrier diffusion and phonon drag contributions in $M_3C_{60}$ (M = K, Rb) alkali intercalated fullerides.
Źródło:: Acta Physica Polonica A; 2013, 123, 4; 752-760
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 83.

Tytuł:: Critical Current Problems in Neutrons Irradiated HTc Multilayered Superconductors
Autorzy:: Sosnowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1398613.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Wx
74.25.Sv
Opis:: In the paper there is given an analysis of the critical current problems in irradiated multilayered high temperature oxide superconductors. Critical current for the direction of current flow inside the layers is investigated basing on analysis of the capturing interaction of pancake vortices with nanodefects, created by fast neutrons irradiation. Analysis of the pinning potential barrier formation is presented. From performed calculations of current-voltage characteristics fitted to measurements the inherent pinning centers concentration and their average dimensions were estimated. The case of perpendicular to layers current has been regarded too, taking into account the intrinsic Josephson junctions formation. The influence of nanodefects concentration on the Josephson penetration depth has been considered, whose length determines the Swihart velocity and current-voltage characteristics of junction.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 585-587
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 84.

Tytuł:: Superconductivity and Ferromagnetism in $La_{0.67}Sr_{0.33}MnO_3//YBa_2Cu_3O_7$ Nanosized Heterostructures
Autorzy:: Lochmajer, H.
Matusiak, M.
Urbanik, G.
Przyslupski, P.
Rogacki, K.
Powiązania:: https://bibliotekanauki.pl/articles/1398624.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.fc
74.25.fg
74.78.Fk
Opis:: In this work we present recent experimental studies of heterostructures composed of ferromagnetic $La_{0.67}Sr_{0.33}MnO_3$ (LSMO) and superconducting $YBa_2Cu_3O_7$ (YBCO) multilayers grown by dc sputtering method. The transport and magnetic properties of the large set of heterostructures were investigated in a wide temperature range from 2 to 400 K and in fields up to 12.5 T. The resistivity and the upper critical field were measured for samples with the plane active dimensions 1.5× 5 mm². The Nernst effect was studied in the mixed state revealing the characteristic temperature dependence of the Nernst signal which was correlated with variation of the upper critical field. We have observed an influence of the magnetic LSMO layer on the superconducting properties of the adjacent YBCO layer which consists in a substantial reduction of the superconducting critical temperature and a small lowering of the upper critical field.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 588-592
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 85.

Tytuł:: Superconducting Instability Temperature of a Non-Centrosymmetric System
Autorzy:: Grzybowska, D.
Harań, G.
Powiązania:: https://bibliotekanauki.pl/articles/1398637.pdf
Data publikacji:: 2016-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.62.-c
74.70.-b
Opis:: We discuss a direct effect of the energy band splitting due to the antisymmetric spin-orbit coupling on the superconducting phase transition. Employing the square lattice tight-binding model we show a significant contribution of the spin-split energy band to the pair-breaking effect in the weak- and intermediate-coupling non-centrosymmetric superconductors. We establish a general tendency of the spin-orbit coupling to suppress the critical temperature of the spin singlet and triplet states. For the weak-coupling systems we report a possible development of sharp maxima of the critical temperature for the band fillings which support the spin-orbit coupling induced Fermi surface singularities of the density of states. We note that the initial suppression of the most stable triplet state becomes comparable to the suppression of other triplet states in the intermediate-coupling regime of superconductivity.
Źródło:: Acta Physica Polonica A; 2016, 130, 2; 604-606
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 86.

Tytuł:: Modelling of Critical Current Density of Sintered Ag Added Bulk MgB₂
Autorzy:: Santosh, M.
Powiązania:: https://bibliotekanauki.pl/articles/1398972.pdf
Data publikacji:: 2016-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.Sv
74.20.-z
Opis:: Magnetic field dependence of critical current density $(J_{c})$ of bulk MgB₂ material at 20 K is reported. The selected sintered MgB₂ materials contained various amounts of silver. The silver added samples possess always a higher critical current density than the silver free ones. The critical current density increased with silver content and continuously decreased with increase of magnetic field. Further, the normalized volume pinning force density,$ f_{p}=F_{p}//F_{p,max}$, versus reduced field $h = H_{a}// H_{irr}$ for silver free and silver added samples suggested that grain boundary pinning is dominant. In essence, the model of thermal activated flux motion was successfully applied to fit the critical current density of the MgB₂ materials.
Źródło:: Acta Physica Polonica A; 2016, 129, 6; 1197-1200
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 87.

Tytuł:: Magnetism and Superconductivity in Iron Pnictides
Autorzy:: Singh, D.
Powiązania:: https://bibliotekanauki.pl/articles/1426673.pdf
Data publikacji:: 2012-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.70.Xa
74.20.Rp
74.20.Pq
Opis:: The discovery of high temperature superconductivity in iron pnictides and chalcogenides has resulted in surprising new insights into high temperature superconductivity and its relationship with magnetism. Here we provide an overview of some of what is known about these materials and in particular about the interplay of magnetism and superconductivity in them. Similarities and contrasts with cuprate superconductors are emphasized and the superconducting pairing is discussed within the framework of spin fluctuation induced pairing.
Źródło:: Acta Physica Polonica A; 2012, 121, 5-6; 999-1004
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 88.

Tytuł:: Coherence Lengths for Superconductivity in the Two-Orbital Negative-U Hubbard Model
Autorzy:: Litak, G.
Örd, T.
Rägo, K.
Vargunin, A.
Powiązania:: https://bibliotekanauki.pl/articles/1431204.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.20.Mn
74.25.-q
Opis:: We study the peculiarities of coherency in the superconductivity of two-orbital system. The superconducting phase transition is caused here by the on-site intra-orbital attractions (negative-U Hubbard model) and inter-orbital pair-transfer interaction. The dependencies of critical and non-critical correlation lengths on interaction channels and band fillings are analyzed.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 747-751
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 89.

Tytuł:: Strong-Coupling Description of the High-Temperature Superconductivity in the Molecular Hydrogen
Autorzy:: Szczęśniak, R.
Jarosik, M.
Powiązania:: https://bibliotekanauki.pl/articles/1431357.pdf
Data publikacji:: 2012-04
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: The detailed study of the selected thermodynamic properties of the superconducting phase in the molecular hydrogen under the pressure at 428 GPa has been presented. For the increasing value of the Coulomb pseudopotential $μ^{*}$ ∈〈0.08,0.15〉, the following results have been obtained: (i) the critical temperature decreases from 179 K to 141 K, (ii) the ratio $R_{1}$≡ 2Δ(0)/$k_{B}T_{C}$ differs noticeably from the BCS value: $R_{1}$∈〈4.71,3.60〉; (iii) the electron effective mass is large and grows slightly together with the temperature $([m^{*}_{e}//m_{e}]_{max}=2.2 for T = T_{C})$.
Źródło:: Acta Physica Polonica A; 2012, 121, 4; 841-844
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 90.

Tytuł:: Fluxonic Properties of Vortices in a Washboard Pinning Potential Fabricated by Focused Particle Beam Techniques
Autorzy:: Dobrovolskiy, O.
Huth, M.
Shklovskij, V.
Powiązania:: https://bibliotekanauki.pl/articles/1490776.pdf
Data publikacji:: 2012-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.F-
74.25.Wx
74.25.Sv
Opis:: A challenging aspect of the usage of patterned nanostructures relates to the development of superconducting devices operating with the Abrikosov vortices in some pinning potential. To provide such a potential we have used thin epitaxial films of Nb with washboard-like nanostructures in the form of grooves or Co stripes. The nanostructures were prepared by focused ion beam milling or focused electron beam induced deposition, respectively. The results of transport measurements affirm the existence of two fluxonic effects, the guided vortex motion and the vortex ratchet effect, both invoked by the nanostructuring. In particular, the effects represent the basis for the development of advanced fluxonic devices using a directional or orientational control of the net vortex motion in Nb films nanostructured by focused particle beam techniques.
Źródło:: Acta Physica Polonica A; 2012, 121, 1; 82-84
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 91.

Tytuł:: The Properties of the Superconducting State in $YNi_2B_2C$: The One-Band Eliashberg Approach
Autorzy:: Jarosik, M.
Szczęśniak, R.
Powiązania:: https://bibliotekanauki.pl/articles/1505119.pdf
Data publikacji:: 2011-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.25.Ha
Opis:: The basic thermodynamic parameters of the superconducting state in $YNi_2 B_2 C$ were calculated in the framework of the one-band Eliashberg model. The effective Eliashberg function, determined on the basis of the transport function, was used during calculations. It was shown that the dimensionless ratios are equal to: $R_1$ ≡ 2Δp(0)/$k_{B}$ $T_{C}$ = 3.87, $R_2$ ≡ ΔC($T_{C})//C^{N}(T_{C})$ = 1.79 and $R_3$ ≡ $T_{C} C^{N}(T_{C}) // H_{C}^2(0)$ = 0.159. The value $R_1$ fairly agrees with the experimental data whereas $R_2$ and $R_3$ agree very well.
Źródło:: Acta Physica Polonica A; 2011, 119, 6; 863-867
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 92.

Tytuł:: Thermodynamic Critical Magnetic Field for Chlorine Halide Superconductor at High Pressure
Autorzy:: Szczęśniak, D.
Szczęśniak, R.
Powiązania:: https://bibliotekanauki.pl/articles/1382363.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Fg
74.25.Bt
74.62.Fj
Opis:: At present, hydrides are considered as a one of the most interesting high-temperature superconductors with the classical electron-phonon pairing mechanism. In the present paper, we have analyzed the dependence of the thermodynamic critical magnetic field $(H_c)$ on the temperature for the chlorine halide superconductor. The calculations have been made in the framework of the Eliashberg formalism for the following pressure values: $p_{1}$=320 GPa and $p_{2}$=360 GPa. We have shown that $H_c$ increases strongly with the increase of the pressure: $[H_c(0)]_{p_{2}}$/$[H_c(0)]_{p_{1}}$= 1.43. Furthermore, the dimensionless ratio: $R_{H}$ ≡ $T_cC^{N}(T_c)$/$H_c^{2}(0)$, where $T_c$ and $C^{N}$ denote the critical temperature and the specific heat of the normal state, differs from the value predicted by the Bardeen-Cooper-Schrieffer theory. In particular: $[R_{H}]_{p_{1}}$=0.166 and $[R_{H}]_{p_{2}}$=0.158.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 344-345
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 93.

Tytuł:: Pairing Correlations around Negative-U Centre in the Two-Band Model
Autorzy:: Ciechan, A.
Wysokiński, K.
Powiązania:: https://bibliotekanauki.pl/articles/1812284.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.81.-g
74.90.+n
Opis:: The electron energy spectrum of many superconducting materials is characterised by the presence of few bands at the Fermi level. In some cases the superconducting properties seem to be dominated by single band but in others the many-band approach is essential ingredient of their description. In this paper we shall study the properties of superconducting impurity placed in a non-superconducting medium. We are interested in the evolution of superconducting correlations within non-superconducting 1- or 2-dimensional system, their dependence on the distance from impurity and changes induced by the presence of the second band and interband scattering. We use real space description of the material and Bogolyubov-de Gennes approach to superconductivity.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 123-127
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 94.

Tytuł:: s-Wave Order Parameter in the Presence of a Momentum-Dependent Impurity Scattering Potential
Autorzy:: Rudzińska, D.
Pisarski, P.
Harań, G.
Powiązania:: https://bibliotekanauki.pl/articles/1812291.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.Dh
74.78.-w
74.81.-g
Opis:: Momentum dependence of the impurity potential leads to the anisotropy of a local density of states in isotropic s-wave superconductors. We complete this result by discussing the influence of a momentum-dependent impurity potential on the s-wave order parameter. The scattering process is considered in the T-matrix approximation, and the model impurity potential consists of two separate terms representing isotropic (on-site) and anisotropic (momentum-dependent) parts of the potential. We show that the effect of the isotropic part on the order parameter is local whereas the influence of the momentum-dependent term is nonlocal.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 149-152
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 95.

Tytuł:: Resonant States of a Momentum-Dependent Impurity Potential in a d-Wave Superconductor
Autorzy:: Pisarski, P.
Harań, G.
Powiązania:: https://bibliotekanauki.pl/articles/1812293.pdf
Data publikacji:: 2008-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Rp
74.62.Dh
74.72.-h
Opis:: Nonmagnetic impurity on-site potential leads to the resonant states in a d-wave superconductor for the unitary scattering limit. We extend the above study to include a momentum dependence of the impurity potential and discuss the existence and number of resonant states for a tetragonal anisotropy of the scattering potential.
Źródło:: Acta Physica Polonica A; 2008, 114, 1; 153-157
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 96.

Tytuł:: Dynamics of Hotspot Formation in Nanostructured Superconducting Stripes Excited with Single Photons
Autorzy:: Jukna, A.
Kitaygorsky, J.
Pan, D.
Cross, A.
Perlman, A.
Komissarov, I.
Sobolewski, R.
Okunev, O.
Smirnov, K.
Korneev, A.
Chulkova, G.
Milostnaya, I.
Voronov, B.
Gol'tsman, G.
Powiązania:: https://bibliotekanauki.pl/articles/1813380.pdf
Data publikacji:: 2008-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.25.Fy
74.25.Sv
74.45.+c
Opis:: Dynamics of a resistive hotspot formation by near-infrared-wavelength single photons in nanowire-type superconducting NbN stripes was investigated. Numerical simulations of ultrafast thermalization of photon-excited nonequilibrium quasiparticles, their multiplication and out-diffusion from a site of the photon absorption demonstrate that 1.55 μm wavelength photons create in an ultrathin, two-dimensional superconducting film a resistive hotspot with the diameter which depends on the photon energy, and the nanowire temperature and biasing conditions. Our hotspot model indicates that under the subcritical current bias of the 2D stripe, the electric field penetrates the superconductor at the hotspot boundary, leading to suppression of the stripe superconducting properties and accelerated development of a voltage transient across the stripe.
Źródło:: Acta Physica Polonica A; 2008, 113, 3; 955-958
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 97.

Tytuł:: Codoping Effect of Zn and Pr in $YBa_2Cu_3O_{7-δ}$
Autorzy:: Naik, M.
Sarode, P.
Prabhu, R.
Priolkar, K.
Vasanthacharya, N.
Powiązania:: https://bibliotekanauki.pl/articles/1808131.pdf
Data publikacji:: 2009-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.62.Bf
74.62.Dh
74.72.Bk
Opis:: In this paper we present the resistivity data for Pr and Zn codoped compound $Y_{1-x}Pr_xBa_2[Cu_{1- y}Zn_y]_3O_{7-δ}$ with 0 & y & 0.1 and x=0.0, 0.1 and 0.2. The data is analysed in terms of the superconducting critical temperature $T_c$, residual resistivity $ρ_0$ and the resistivity slope dρ/dT corresponding to the linear ρ-T region. It is found that for x=0.1 Pr has a minimal influence on the in-plane processes for Zn impurity alone affecting slightly $T_c$ and $ρ_0$. The slope dρ/dT becomes larger for 0.03 & y & 0.06 leading to larger depining effect and hence slower fall of $T_c$ as a function of y. For x = 0.2 there is a drastic change, $ρ_0$ becomes abnormally large, dρ/dT becomes negative implying absence of depinning and a totally pinned charge stripes. Superconductivity vanishes at y=0.03. It is concluded that for x = 0.2 Pr converts the system from overdoped to underdoped region leading to the universal superconductor-insulator transition.
Źródło:: Acta Physica Polonica A; 2009, 115, 3; 742-744
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 98.

Tytuł:: On Strong Coupling Theory of Correlated Superconductors
Autorzy:: Wysokiński, K. I.
Powiązania:: https://bibliotekanauki.pl/articles/1955487.pdf
Data publikacji:: 1997-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.-z
74.25.Kc
74.20.Mn
Opis:: The strong coupling or Eliashberg equations of superconductivity have been generalised to describe strongly correlated systems. Calculations show that d-wave superconductivity is stable for small hole doping. It also follows that in correlated systems one should define three different Eliashberg functions and corresponding electron- phonon coupling constants λ$\text{}_{N}$, λ$\text{}_{S}$ and λ$\text{}_{tr}$ (to describe normal (N), superconducting (S) and transport (tr) properties) each of which is measured in different kind of experiment.
Źródło:: Acta Physica Polonica A; 1997, 91, 2; 329-332
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 99.

Tytuł:: Superconductivity in Anderson Lattice Model
Autorzy:: Romano, A.
Noce, C.
Micnas, R.
Powiązania:: https://bibliotekanauki.pl/articles/1955827.pdf
Data publikacji:: 1997-02
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.70.Tx
74.25.-q
Opis:: We study the superconducting instabilities generated by the inclusion in the Anderson lattice model of a density-density attractive potential between correlated electrons on nearest-neighbouring sites. Using a description of the normal phase based on a perturbative expansion around the atomic limit, we treat the attractive potential in the broken-symmetry Hartree-Fock scheme and analyze which of the possible symmetries of the superconducting order parameter leads to the highest possible transition temperature in the case of a two-dimensional square lattice. For values of the on-site f-repulsion large compared to the hopping amplitude, a suppression of any possible superconducting phase occurs, regardless of the symmetry of the order parameter.
Źródło:: Acta Physica Polonica A; 1997, 91, 2; 381-385
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 100.

Tytuł:: Simple Band Model of Doped Fullerene Crystal
Autorzy:: Koper, A.
Mucha, M.
Powiązania:: https://bibliotekanauki.pl/articles/2012907.pdf
Data publikacji:: 2000-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.20.Mn
74.25.Kc
74.25.Jb
Opis:: We use quantum billiard with many scattering centers to describe conducting electrons properties in A$\text{}_{n}$C$\text{}_{60}$ crystals, where A denotes alkali metal. We focus our attention on the A$\text{}_{3}$C$\text{}_{60}$ crystal, for which we calculate the band structure, density of states, and conductivity for normal electrons. Conductivity shows linear dependence on temperature in this model, which agrees well with experimental data. We also discuss consequences of our results for superconductivity mechanism in A$\text{}_{3}$C$\text{}_{60}$ and possibilities of analogous approach to describe electron properties in fused fullerenes and multiply connected carbon clusters.
Źródło:: Acta Physica Polonica A; 2000, 97, 1; 233-236
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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