Temat: 74.25.-q - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

Artykuł

Skocz do pozycji: 2.

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

Artykuł

Skocz do pozycji: 3.

Tytuł:: Non-Fermi Liquid States of a General Model of Copper-Oxide Metals
Autorzy:: Varma, C. M.
Powiązania:: https://bibliotekanauki.pl/articles/1953178.pdf
Data publikacji:: 1997-01
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 71.10.Hf
74.72.-h
74.20.Mn
74.25.-q
Opis:: A summary is given of the minimum requirements posed by experimental results on a theory of copper-oxide metals and of the recent solution of a model of copper-oxygen bonding and anti-bonding bands with the most general two-body interactions allowable by symmetry which satisfies these requirements. Several experiments were proposed to test the theory.
Źródło:: Acta Physica Polonica A; 1997, 91, 1; 191-201
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Changes in YBCO Single Grain Bulk Superconductor Exposed to Air Moisture
Autorzy:: Piovarči, S.
Antal, V.
Kaňuchová, M.
Radušovská, M.
Diko, P.
Powiązania:: https://bibliotekanauki.pl/articles/1202072.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 74.72.-h
74.25.-q
68.43.-h
68.37.-d
Opis:: Changes in bulk single grain YBCO superconductor at exposition to air were studied. The increase of the sample weight caused by reaction with air moisture was observed by weighing the samples over two months period. Thermal analyses and mass spectrometry of the exposed samples has shown evolution of water and oxygen during sample heating. Observation with scanning electron microscope confirmed the formation of some nanosize phases at the inner sample surfaces. XPS spectra done on the freshly cleaved and on the air exposed (001) surfaces confirmed changes in Ba and Cu bonds. Observed structural changes did not caused systematic changes in measured trapped field.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 364-365
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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