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Wyszukujesz frazę "74.25.Nf" wg kryterium: Temat


Wyświetlanie 1-8 z 8
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
Artykuł
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
Artykuł
Tytuł:
Josephson Network as a Model for Inhomogeneous Superconductor: a Microwave Power Absorption
Autorzy:
Rycerz, A.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047320.pdf
Data publikacji:
2007-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.81.Fa
74.25.Nf
Opis:
We discuss the applied magnetic field dependence of the microwave absorption by a three-dimensional array of up to 30×30 ×30 Josephson junctions with random parameters including the resistivity, capacity, and inductance of each junction. The numerical simulation results for the networks show characteristic microwave absorption anomalies observed in the ceramic samples of high temperature superconductor YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$. We also provide a discussion of the absorption in simple analytical terms of the Josephson loop instabilities.
Źródło:
Acta Physica Polonica A; 2007, 111, 4; 581-594
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superconducting Properties of Mo$\text{}_{2}$Re$\text{}_{3}$B$\text{}_{x}$-Mo$\text{}_{3}$Re$\text{}_{2}$B$\text{}_{x}$ Eutectic
Autorzy:
Andrzejewski, B.
Guilmeau, E.
Kowalczyk, A.
Jurga, W.
Powiązania:
https://bibliotekanauki.pl/articles/2047335.pdf
Data publikacji:
2007-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Yz
74.10.+v
74.25.Ha
74.25.Nf
74.50.+r
Opis:
We synthesized, for the first time, superconducting eutectic composed of two new superconducting phases, namely of Mo$\text{}_{2}$Re$\text{}_{3}$B$\text{}_{x}$ and of Mo$\text{}_{3}$Re$\text{}_{2}$B$\text{}_{x}$ (where x≈1) and investigated its basic transport, magnetic, and microwave properties. The transition temperatures T$\text{}_{c}$ were equal to 6.6 K and to 8.7 K for Mo$\text{}_{3}$Re$\text{}_{2}$B$\text{}_{x}$ and Mo$\text{}_{2}$Re$\text{}_{3}$B$\text{}_{x}$ compound, respectively. The phases present in the eutectic were identified by means of energy dispersion spectroscopy analyses. It was also shown that the two phases in the eutectic were separated by thin boron interface and formed regular network of the Josephson junctions which very effectively absorbed microwave energy.
Źródło:
Acta Physica Polonica A; 2007, 111, 5; 727-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Influence of DC Magnetic Field on AC Loss of YBCO Coated Conductor with Ferromagnetic Substrate
Autorzy:
Vojenčiak, M.
Šouc, J.
Gömöry, F.
Seiler, E.
Powiązania:
https://bibliotekanauki.pl/articles/1813686.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Fy
74.25.Nf
74.78.Bz
75.50.-y
Opis:
Most of YBCO tape conductors are prepared on a ferromagnetic substrate. The ferromagnetic material is then exposed to the self magnetic field of the superconductor and also to external magnetic field. In AC magnetic field hysteretic and eddy current losses are generated in the substrate. In this work the AC transport loss of an YBCO coated conductor on a ferromagnetic substrate was measured using electromagnetic method. There are two contributions to total loss - a loss in the superconductor and a loss in the substrate. To suppress the hysteretic loss in the substrate, it is possible to saturate it using DC magnetic field. In this regime significant decrease in total loss was observed.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 359-362
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Ferromagnetic Layer on Critical Current of a Superconducting Wire
Autorzy:
Gömöry, F.
Vojenčiak, M.
Šouc, J.
Seiler, E.
Powiązania:
https://bibliotekanauki.pl/articles/1813946.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Gz
74.25.Fy
74.25.Nf
Opis:
We investigated how a 10-50 μm layer from soft ferromagnetic material, incorporated in the architecture of a composite superconducting tape, could influence the capability of the tape to transport electrical current. Numerical procedure was developed to calculate the local distribution of magnetic field and current in the condition when all the superconductor is carrying its critical current density. It was found that the concentration of magnetic flux in ferromagnetic layers allows to reduce the local value of magnetic flux density felt by the superconductor. In this way, the critical current of the tape in low applied magnetic fields can be improved. This theoretical prediction is confirmed by experimental observation.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 605-608
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
    Wyświetlanie 1-8 z 8

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