Autor: Gritzner, G. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Temperature and Magnetic Field Dependences of Critical Current of Thallium-Based Superconducting Films
Autorzy:: Zalecki, R.
Kołodziejczyk, A.
Heiml, O.
Gritzner, G.
Tematy:: 74.25.Sv
74.78.Bz
74.72.Jt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2046810.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

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.
Tematy:: 74.72.-h
74.40.-n
74.20.De
74.25.Ha; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1426876.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Photoemission Electronic States of Thallium- and Bismuth-Based Superconductors
Autorzy:: Zalecki, R.
Kołodziejczyk, A.
König, J. W.
Gritzner, G.
Tematy:: 74.72.-h
79.60.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014372.pdf Link otwiera się w nowym oknie
Opis:: X-ray photoemission spectra the core-levels as well as the X-ray photoemission spectra and ultraviolet photoemission spectra from the valence bands of the (Tl$\text{}_{0.6}$Pb$\text{}_{0.5}$)(Sr$\text{}_{0.9}$Ba$\text{}_{0.1}$) Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{y}$ and (Bi$\text{}_{1.75}$Pb$\text{}_{0.35}$)Sr$\text{}_{1.9}$Ca$\text{}_{2.05}$Cu$\text{}_{3.05}$O$\text{}_{y}$ superconductors were measured and analyzed. Special attention was paid to the valence band X-ray photoemission spectra and ultraviolet photoemission spectra, the Cu 2p core-level X-ray photoemission spectra and the Cu L$\text{}_{2,3}$-M$\text{}_{4,5}$M$\text{}_{4,5}$ and O K-L$\text{}_{2,3}$L$\text{}_{2,3}$ Auger spectra. Both Cu 2p$\text{}_{3}\text{}_{/}\text{}_{2}$ and Cu 2p$\text{}_{1}\text{}_{/}\text{}_{2}$ core-level lines consisted of two spin-orbit split main lines accompanied with the two satellite lines. The charge transfer energy Δ from the oxygen ligand to the copper 3d$\text{}^{9}$ states and the hopping integral t were estimated from the energy separation between the main line and the satellite line taking advantage of the local cluster model calculations and their extension to high-temperature superconductors. The Coulomb correlation on-site energy U$\text{}_{dd}$ of two electrons in the same copper orbital and U$\text{}_{pp}$ of two electrons in the oxygen orbital as well as the correlation energy U$\text{}_{cd}$ of the 2p core hole - 3d electron interaction have been estimated from the Auger electron spectra and the valence band spectra. They are: U$\text{}_{dd}$=6.0±0.5eV, of U$\text{}_{pp}$≅ 10±1eV and of U$\text{}_{cd}$≅ 8.0±0.5eV nearly the same for both the Tl- and Bi-compounds. We conclude that these compounds are the charge transfer strongly-correlated metals.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Bismuth Valence in a $Tl_{0.7}Bi_{0.3}Sr_{1.6}Ba_{0.4}CaCu_{2}O_{y}$ Superconductor from X-Ray Photoemission Spectroscopy
Autorzy:: Zalecki, R.
Woch, W.
Kowalik, M.
Kołodziejczyk, A.
Gritzner, G.
Tematy:: 74.72.-h
74.25.Jb
79.60.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1537186.pdf Link otwiera się w nowym oknie
Opis:: The X-ray electron photoemission spectra of a $Tl_{0.7}Bi_{0.3}Sr_{1.6}Ba_{0.4}CaCu_2O_{y}$ superconductor were measured with $Al K_{α}$ and $Mg K_{α}$ radiation at room temperature. The Bi 4f spectrum was compared to the same spectra of $Bi_{1.75}Pb_{0.35}Sr_{1.9}Ca_{2.05}Cu_{3.05}O_{y}$ and $Tl_{0.6}Pb_{0.4}Sr_{1.6}Ba_{0.4}Ca_2Cu_3O_{y}$ superconductors. In Bi,Pb-based superconductor only one type of $Bi^{3+}$ ions is present. The Bi 4f spectrum in the Tl,Bi-superconductor consists of two contributions due to the different valences. The component from $Bi^{5+}$ lines is in higher binding energy than from $Bi^{3+}$. The ratio of trivalent $Bi^{3+}$ to pentavalent $Bi^{5+}$ bismuth ions was calculated from decomposition of the spin-orbit split spectrum of the Bi 4f photoelectrons. The conclusion is that Bi is present in trivalent and in pentavalent form and the ratio of $Bi^{3+}$ to $Bi^{5+}$ is 1.87 ± 0.02.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Study of Resistive Superconducting Transition of Thallium Based Superconductors
Autorzy:: Woch, W.
Zalecki, R.
Chrobak, M.
Kołodziejczyk, A.
Gritzner, G.
Tematy:: 74.72.-h
74.40.n
74.20.De
74.25.Ha; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1431253.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

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.
Tematy:: 74.72.-h
74.25.Ha
74.25.Wx
74.20.De; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1374160.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

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.
Tematy:: 74.72.Fq
74.25.Ha
74.72.Bk
74.72.Hs
74.25.Bt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1955838.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Inter- and Intragrain Magnetization of Thallium-Based Superconductors
Autorzy:: Tokarz, W.
Kąkol, Z.
Kołodziejczyk, A.
König, W.
Gritzner, G.
Tematy:: 74.72.Fq
74.72.-h
74.50.+r; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2014492.pdf Link otwiera się w nowym oknie
Opis:: We report on magnetization and magnetic hysteresis measurements for the (Tl$\text{}_{0.6}$Bi$\text{}_{0.5}$)(Sr$\text{}_{0.9}$Ba$\text{}_{0.1}$)$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{y}$ Ag-sheathed superconducting tape as well as for the powdered and bulk (Tl$\text{}_{0.6}$Pb$\text{}_{0.5}$)(Sr$\text{}_{0.9}$Ba$\text{}_{0.1}$)$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{y}$ superconductors. For the investigated tape and bulk specimens the low field magnetization showed a deviation from the ideal linear M(H) dependence, which was attributed to the superposition of inter- and intragrain superconducting currents. Fitting of the theoretical magnetization curves to the experimental data allowed for the independent determination of the intragrain critical current densities for the superconducting grains and intergrain critical current densities for the weak link system at 77K.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Irreversibility Fields of (Tl$\text{}_{0.5}$Pb$\text{}_{0.5}$) (Sr$\text{}_{0.85}$Ba$\text{}_{0.15}$)$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{z}$ Film on Polished Silver Substrate
Autorzy:: Woch, W. M.
Zalecki, R.
Kołodziejczyk, A.
Deinhofer, C.
Gritzner, G.
Tematy:: 74.25.Sv
74.78.Bz
74.62.Yb; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047336.pdf Link otwiera się w nowym oknie
Opis:: Superconducting (Tl$\text{}_{0.5}$Pb$\text{}_{0.5}$)(Sr$\text{}_{0.85}$Ba$\text{}_{0.15}$)$\text{}_{2}$Ca$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{z}$ film was prepared on a highly polished, untextured silver substrate. A superconducting transition temperature (T$\text{}_{c,50%}$) of 114.7±0.3 K was obtained from the resistance versus temperature measurements for different applied ac currents. The density of the critical current measured by transport method was found to be 11.4×10$\text{}^{3}$ A/cm$\text{}^{2}$ at 77 K in the self field. This value is smaller than the value calculated from ac susceptibility data: 53×10$\text{}^{3}$ A/cm$\text{}^{2}$ at 77 K. The magnetical broadening of the resistivity transition to the superconducting state was observed. The irreversibility fields of the thallium based film were obtained from magnetoresistive measurements for both parallel to the c-axis and parallel to the $ab$ plane showing the anisotropy according to the magnetic field direction. The irreversibility fields as a function of temperature were successfully fitted by the power law.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

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.
Tematy:: 74.72.Jt
74.25.Sv
74.25.Ha; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1812280.pdf Link otwiera się w nowym oknie
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.
Dostawca treści:: Biblioteka Nauki

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