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    Wyświetlanie 1-48 z 48
    Tytuł:
    Electron-Molecular Vibration Coupling in TTF-Based Donors
    Autorzy:
    Pokhodnia, K. I.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933373.pdf
    Data publikacji:
    1995-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    Opis:
    BEDT-TTF, BMDT-TTF and BEDO-TTF are well known thio-TTF and oxo-TTF (in the former case) derivatives on the basis of which cation-radical salts with 2D type of conductivity can be produced. In this work the comparative analysis of electron-molecular vibration coupling constants (obtained by MNDO quantum-chemical method) that describe the interaction between totally symmetric A$\text{}_{g}$ modes and electron on HOMO level is performed.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 4-5; 815-818
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Critical Behaviour of Pyroelectric-Type Superconductors
    Autorzy:
    Krzyżanowski, I. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/1887981.pdf
    Data publikacji:
    1991-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    67.50.-b
    74.70.-b
    Opis:
    The quasiclassical, Eilenberger-type equations are applied to description of rotating P-wave pyroelectric-type superconductor in the presence of magnetic field H and superflow υ. In analogy to type-II superconductors the possibility of vortex solution is discussed. We determine the symmetry of eigensolutions and the upper critical velocity Ω$\text{}_{c2}$. We discuss the paramagnetic critical behaviour of the system depending on the strength of spin-orbit interaction.
    Źródło:
    Acta Physica Polonica A; 1991, 80, 1; 81-98
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and Characterization of the Superconductor $Mo_3Sb_7$
    Autorzy:
    Tran, V.
    Bukowski, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812274.pdf
    Data publikacji:
    2008-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.25.Bt
    74.70.-b
    Opis:
    We synthesized a polycrystalline sample of the superconductor $Mo_3Sb_7$ and characterized its basic properties by measurements of magnetization, electrical resistivity and specific heat. The measurements establish a superconducting phase transition at $T_c$=2.25 (0.05) K. In applied magnetic fields, the magnetization and resistivity show the behavior of type-II superconductor. From the specific heat measurement, the electronic specific heat coefficient,γ, specific heat jump at $T_c,$ $ΔC(T_c)//γT_c,$ and the Debye temperature $Θ_D$, are evaluated to be 34.5 mJ/(mol $K^2$), 1.56 and 283 K, respectively. From analysis of the specific heat data we suggest that this compound belongs to an intermediate strong coupling regime in the BCS context. The observed enhancement in theγ-value suggests a substantial contribution of Mo-4d-electrons to the density of states. Our experimental data do not support interpretation of superconductivity in $Mo_3Sb_7$ in terms of neither unconventional superconductivity or spin fluctuations proposed previously.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 1; 67-74
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    XANES Experiments for High-Temperature Superconductors
    Autorzy:
    Kołodziejczyk, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1920888.pdf
    Data publikacji:
    1992-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    76.30.-v
    Opis:
    The paper presents the results of XANES (X-ray Absorption Near Edge Structure) experiments, of the high-temperature superconductors of Y-Ba-Cu-O-type carried out at the Cu L$\text{}_{II,III}$- and O K$\text{}_{I}$-edges using synchrotron radiation and the KMC double monochromator and SX-700 grading monochromator beamlines of BESSY/Berlin synchrotron storage ring. The aim of the paper is to show that the XANES studies are well suited for characterization of the local electronic structure of the high-temperature superconductors.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 2; 273-281
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of the Temperature Dependence of the Crystal Structure of $LiTi_2O_4$ and $LiV_2O_4$
    Autorzy:
    Moshopoulou, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/1813759.pdf
    Data publikacji:
    2008-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    61.05.fm
    Opis:
    The normal spinel oxide $LiTi_2O_4$ is an exotic superconductor with $T_c$=11.2 K, while the isostructural neighbouring $LiV_2O_4$ exhibits heavy-fermion behaviour. The origin of their physics and the role of the spinel structure on their properties are yet unsolved issues, owing mainly to the complexity of the structure, the presence of subtle disorder, and the sample dependence of the physical properties. Especially and perhaps more importantly, the enormous difference in their low-temperature properties remains an open question. This question has only been addressed theoretically but (mainly because of the above problems) there were no experimental studies that sought to understand the clearly distinct behaviour of the two systems. Here, we contribute to the understanding of such distinct low-temperature behaviour by comparing the temperature dependence of the very basic structural properties of the two systems. Upon cooling from room temperature, the lattice parameter a decreases gradually in about the same way for both systems. However, below 20 K, a clear decrease in a of $LiV_2O_4$ as a function of temperature contrasts strongly with the almost constant value of a of $LiTi_2O_4$ in the same temperature range. Therefore subtle but clearly different structural signatures are coupled with the very divergent physical properties of the two systems and suggest new directions to the theory.
    Źródło:
    Acta Physica Polonica A; 2008, 113, 1; 399-402
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Evolution of Superconducting Phase $MgB_x$
    Autorzy:
    Łoś, Sz.
    Kempiński, W.
    Piekara-Sady, L.
    Andrzejewski, B.
    Jurga, W.
    Kaszyńska, K.
    Piekoszewski, J.
    Werner, Z.
    Barlak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812318.pdf
    Data publikacji:
    2008-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    74.78.-w
    Opis:
    Thin layers of $MgB_x$ were studied in order to define evolution of superconducting phase after Mg ions implantation into boron substrate. Three fluencies of energies 140, 80, and 40 keV were used to establish proper stoichiometry to synthesize homogeneous $MgB_2$ film. Additionally, the annealing processes were carried out at temperatures 400, 500, and 600°C in a furnace in an atmosphere of flowing $Ar-4%H_2$ gas mixture. The quality of the superconducting material was examined by magnetically modulated microwave absorption, and magnetic and resistivity measurements. The results showed that $T_c$ becomes higher with increasing annealing temperature. However, the fraction of superconducting phase decreases, due to partial evaporation of Mg ions and their deeper migration into boron substrate.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 1; 179-184
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the Surfacegrived State of Cleaved YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ Single Crystals
    Autorzy:
    Harm, S.
    Mante, G.
    Manzke, R.
    Fink, J.
    Skibowski, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1920917.pdf
    Data publikacji:
    1992-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    79.60.-i
    Opis:
    Angle-resolved photoemission experiments on the cleaved surface of YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ single crystals revealed an intrinsic surface-derived electronic state around the X and Y point of the Brillouin zone with 0.92 eV binding energy. A surface electronic structure different to the bulk can be of basic importance for the surface superconductivity of this high-T$\text{}_{c}$ cuprate. Here we briefly review recent experimental results and present new hydrogen adsorption experiments, demonstrating the surface character of the 0.92 eV state.
    Źródło:
    Acta Physica Polonica A; 1992, 82, 2; 349-354
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Formation of Superconducting Regions of MgB_2 by Implantation of Boron Ions into Magnesium Substrate
    Autorzy:
    Trybuła, Z.
    Kempiński, W.
    Andrzejewski, B.
    Piekara-Sady, L.
    Kaszyński, J.
    Piekoszewski, J.
    Werner, Z.
    Richter, E.
    Prokert, F.
    Stanisławski, J.
    Barlak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/2043433.pdf
    Data publikacji:
    2005-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    74.78.-w
    Opis:
    The results of investigation of the MgB$\text{}_{2}$ inter-metallic compound with the use of boron ions implantation and plasma pulse treatment are presented. The samples were characterized by: four-probe electric conductivity measurements, magnetically modulated microwave absorption, and magnetic measurements. For hydrogen and argon pulsed plasma treatment the samples with T$\text{}_{c}$ ranging from 10 K to 32 K were obtained. The superconducting phase does not form a continuous layer since the resistivity does not fall down to zero. Apparently, separate islands of superconducting phase are connected through metallic Mg paths. All samples are still below the percolation threshold.
    Źródło:
    Acta Physica Polonica A; 2005, 108, 1; 165-170
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconducting Regions and Kondo Effect of MgB$\text{}_{2}$ Formed by Implantation of Magnesium Ions into Boron Substrate
    Autorzy:
    Trybuła, Z.
    Kempiński, W.
    Andrzejewski, B.
    Piekara-Sady, L.
    Kaszyński, J.
    Trybuła, M.
    Piekoszewski, J.
    Stanisławski, J.
    Barlak, M.
    Richter, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046803.pdf
    Data publikacji:
    2006-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    74.78.-w
    Opis:
    The results of investigation of the polycrystalline boron implanted by magnesium and argon plasma pulse treatment are presented. The four-probe electric conductivity measurements and magnetically modulated microwave absorption showed the presence of superconducting islands below the temperature of 25 K. Below T=23 K we detected the Kondo effect, a logarithmic increase in the resistivity as the temperature is lowered, due to iron impurity.
    Źródło:
    Acta Physica Polonica A; 2006, 109, 4-5; 657-660
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ion Implantation and Transient Melting: A New Approach to Formation of Superconducting MgB$\text{}_{2}$ Phases
    Autorzy:
    Piekoszewski, J.
    Kempiński, W.
    Stankowski, J.
    Prokert, F.
    Richter, E.
    Stanisławski, J.
    Werner, Z.
    Szymczyk, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/2041609.pdf
    Data publikacji:
    2004-12
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    74.78.-w
    Opis:
    An attempt to synthesize superconducting MgB$\text{}_{2}$ inter-metallic compound from the liquid state is presented. The process consists of two steps. In the first one, boron ions are implanted into a magnesium substrate. In the second one, the near-surface region of such system is melted by short, intense hydrogen plasma pulses without necessity of annealing in Mg vapor. A magnetically modulated microwave absorption method was used to detect superconducting regions in the obtained MgB$\text{}_{2}$ layer. Percolation between nano-regions (islands) of MgB$\text{}_{2}$ has not been observed. However, a superconducting state of the insulated islands has been experimentally proven with transition temperatures T$\text{}_{C}$ as high as 31 K.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 6; 861-868
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Electronic Properties of High-Temperature Superconductor DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ from Critical Fields and Specific Heat Studies
    Autorzy:
    Kołodziejczyk, A.
    Kozłowski, A.
    Chmist, J.
    Zalecki, R.
    Ściężor, T.
    Tarnawski, Z.
    Woch, W. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1929388.pdf
    Data publikacji:
    1993-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    76.30.-v
    Opis:
    The lower and upper critical fields, as well as the specific heat were measured as a function of temperature for good quality DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$ high-temperature superconductor in the vicinity of superconducting transition temperature T$\text{}_{c}$ = 91.2 K. The number of superconducting and normal state electronic quantities were determined basing on the Ginzburg-Landau-Abrikosov-Gorkov theory. It is argued that on the basis of this BCS-like theory one can describe the superconducting properties and, in combination with some information on the electronic structure, also the magnetic properties of high-temperature superconductors.
    Źródło:
    Acta Physica Polonica A; 1993, 84, 1; 127-138
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconductivity of $MgB_2$ Layers Prepared on Silicon Substrate by Implantation of Magnesium Ions into Boron Substrate
    Autorzy:
    Trybuła, Z.
    Kempiński, W.
    Łoś, Sz.
    Kaszyńska, K.
    Trybuła, M.
    Piekoszewski, J.
    Werner, Z.
    Barlak, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1536977.pdf
    Data publikacji:
    2010-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    74.78.-w
    Opis:
    The results of investigation of the $MgB_2$ layers prepared on silicon substrate by implantation of Mg ions into boron substrate are presented. After implantation the annealing processes were carried out at temperatures 673 K, 773 K, and 873 K in a furnace in an atmosphere of flowing Ar-4%$H_2$ gas mixture. The samples were characterized by: four-probe electric conductivity measurements and magnetically modulated microwave absorption. Our results showed that due to silicon substrate the diffusion of implanted Mg ions into boron materials should be limited, and the superconducting phase forms a continuous $MgB_2$ layer and the resistivity for all samples fall down to zero below $T_{c}$. The transition temperature $T_{c}$ becomes higher with increasing annealing temperature: $T_{c}$=18 K (for annealing at $T_{A}$=673 K), $T_{c}$=20 K (for annealing at $T_{A}$=773 K), and $T_{c}$=27 K (for annealing at $T_{A}$=873 K).
    Źródło:
    Acta Physica Polonica A; 2010, 118, 2; 323-325
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Specific Heat of RBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$ and RBaSrCu$\text{}_{3}$O$\text{}_{7-x}$ Compounds (R = Sm, Dy, Er)
    Autorzy:
    Tarnawski, Z.
    Kim-Ngan, N.-T. H.
    Wang, X. Z.
    Duijn, V. H. M.
    Franse, J. J. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1968860.pdf
    Data publikacji:
    1998-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    75.40.-s
    Opis:
    The low-temperature specific-heat C(T) data of high-T$\text{}_{c}$ superconductors RBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-x}$(R123O$\text{}_{7-x}$) were reviewed. A discussion of the C(T) data obtained on single-crystalline samples of Er123O$\text{}_{7-x}$ and Sm123O$\text{}_{7-x}$ compounds in applied magnetic fields for better evaluation of the crystal-electric-field parameters is given. The C(T) measurements of Sr-substituted compounds RBaSrCu$\text{}_{3}$O$\text{}_{7}$ revealed the λ-type of peak related to the antiferromagnetic order at 1.2 K and 0.6 K respectively for Dy- and Er-compounds. The magnetic singlet ground state in these compounds is produced by weak exchange interactions of -0.05 T/μ$\text{}_{B}$ and -0.035 T/μ$\text{}_{B}$, respectively. For Nd- and Sm-compounds, only a broad anomaly around 0.6 K was observed which is well fitted with a Schottky-type anomaly with an energy splitting of 1.4 K.
    Źródło:
    Acta Physica Polonica A; 1998, 93, 3; 513-522
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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
    Artykuł
    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
    Artykuł
    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
    Artykuł
    Tytuł:
    Chemical Potential as a Detector of Phase Transitions in Solids
    Autorzy:
    Matlak, M.
    Gosławska, E.
    Grabiec, B.
    Eid, Kh.
    Powiązania:
    https://bibliotekanauki.pl/articles/2012963.pdf
    Data publikacji:
    2000-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    75.30.Kz
    75.40.Cx
    Opis:
    We show that the chemical potential exhibits small but distinct kinks at all critical temperatures as the evidence for phase transitions in the electronic system, structural phase transitions included. In the case of, at least, two kinds of interacting electrons average occupation numbers exhibit the same behavior.
    Źródło:
    Acta Physica Polonica A; 2000, 97, 3; 365-368
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chemical Potential Evidence for Phase Transitions in Magnetic and Superconducting Compounds and Alloys
    Autorzy:
    Matlak, M.
    Pietruszka, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/2012914.pdf
    Data publikacji:
    2000-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.-b
    75.30.Kz
    75.40.Cx
    Opis:
    We announce that all phase transitions (induced by temperature or concentration) including structural ones and transitions between metastable or "exotic" states can be detected by the chemical potential critical behaviour, as well as, from the average occupation numbers of the electronic system (critical electron redistribution).
    Źródło:
    Acta Physica Polonica A; 2000, 97, 1; 253-256
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    First Principles Calculation of ε-Phase of Solid Oxygen
    Autorzy:
    Kamaruddin, K.
    Abedin, A.
    Zabidi, N.
    Yahya, M.
    Taib, M.
    Rosli, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398703.pdf
    Data publikacji:
    2016-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.20.Pq
    74.70.-b
    31.15.E-
    75.50.Xx
    Opis:
    The electronic structures of ε-phase of solid oxygen (O₂)₄ are studied within the framework of density-functional theory. The intriguing molecule has been known to have magnetic properties at room temperature by applying pressure. Nevertheless, until now there was no evidence of band structure studied in the antiferromagnetic behaviour of (O₂)₄. We report a comparison study for spin and non-spin polarization orbital which suggests that this ferromagnetic configuration of (O₂)₄ could not be seen experimentally, and antiferromagnetic configuration of (O₂)₄ was seen at higher pressure of about 10 GPa. The antiferromagnetic state transforms into the superconducting state as the sample temperature decreases. The results can serve as a useful approximation in studying general features of the electronic structure. The (O₂)₄ clusters are reported in the Raman study, having significant absorption at 1516 cm¯¹ below infrared region.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 4; 468-471
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    XPS Investigation of $Y_{1-x}Dy_xNi_2B_2C$ Superconductors
    Autorzy:
    Winiarski, A.
    Winiarska, A.
    Drzazga, Z.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812333.pdf
    Data publikacji:
    2008-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.20.-b
    74.25.Jb
    74.70.-b
    82.80.Pv
    Opis:
    The analysis of the valence band photoemission spectra of $Y_{1-x}Dy_xNi_2B_2C$ (0≤x≤1) is presented. The valence bands are mainly plotted for Ni 3d, Y 4d and Dy 4f contributions, according to theoretical predictions. The valence bands of $Y_{1-x}Dy_xNi_2B_2C$ compounds markedly change shape with the x parameter, especially in the binding energy region from 3 eV to 14 eV. For large content of Dy (above 55%) the valence band is predominant by Dy 4f states whereas Ni 3d states govern the valence band of yttrium rich compounds. Changing in domination of valence sub-band correlates with plot of superconducting transition temperature $T_c$ with Dy concentration.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 1; 243-246
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Measurement of $YBa_2Cu_3O_{7-δ}$ Single Crystals Using the Atomic/Magnetic Force Microscopy
    Autorzy:
    Kamiński, M.
    Wróblewski, M.
    Susła, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812278.pdf
    Data publikacji:
    2008-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.37.Ps
    68.37.Rt
    74.70.-b
    75.75.+a
    Opis:
    In this paper the experimental investigations of the $YBa_2Cu_3O_{7-δ}$ single crystal, using atomic force microscopy and magnetic force microscopy, are presented. The atomic force microscopy was used to identify oxidized and unoxidized $YBa_2Cu_3O_{7-δ}$ crystal. The $YBa_2Cu_3O_{7-δ}$ single oxidized crystal was examined for magnetic properties by means of magnetic force microscopy. The research was carried out at a room temperature and in the air atmosphere without external magnetic field.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 1; 91-97
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconductivity and Electronic Structure of the W$\text{}_{7}$Re$\text{}_{13}$B Compound
    Autorzy:
    Kowalczyk, A.
    Andrzejewski, B.
    Jezierski, A.
    Toliński, T.
    Szlaferek, A.
    Falkowski, M.
    Chełkowska, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046770.pdf
    Data publikacji:
    2006-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.20.Eh
    74.70.-b
    74.25.Ha
    74.25.Jb
    82.80.Pv
    Opis:
    The superconductor W$\text{}_{7}$Re$\text{}_{13}$B has been studied by the magnetic measurements and microwave absorption. The crystal structure of W$\text{}_{7}$Re$\text{}_{13}$B is cubic (β-Mn type). This compound exhibits a sharp superconducting transition at a temperature of T$\text{}_{c}$=7.2 K. The electronic structure of W$\text{}_{7}$Re$\text{}_{13}$B has been studied by X-ray photoelectron spectroscopy and the band structure has been calculated by the full-potential local-orbital minimum-basis method using the scalar-relativistic mode. The main contribution to the density of states at the Fermi level is from 5d electrons of W and Re. The W and Re bands are similar and substituting W by Re does not change the total density of states.
    Źródło:
    Acta Physica Polonica A; 2006, 109, 4-5; 597-600
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Negative Magnetisation and Absence of Superconductivity in RFe$\text{}_{4}$Al$\text{}_{8}$ (R=Lu, Yb) Compounds
    Autorzy:
    Andrzejewski, B.
    Kowalczyk, A.
    Toliński, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046747.pdf
    Data publikacji:
    2006-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.Dd
    75.50.-y
    75.50.Ee
    51.60.+a
    74.70.-b
    Opis:
    We report researches for superconductivity and the effect of negative magnetisation in the RFe$\text{}_{4}$Al$\text{}_{8}$ (R = Lu, Yb) compounds by means of magnetic measurements and microwave absorption. Contrary to the earlier reports we do not confirm the existence of any traces of superconductivity in these compounds. Instead of the superconductivity and the Meissner effect, the YbFe$\text{}_{4}$Al$\text{}_{8}$ compound exhibits the effect of negative magnetisation, whereas the LuFe$\text{}_{4}$Al$\text{}_{8}$ compound shows an exact antiferromagnetic behaviour.
    Źródło:
    Acta Physica Polonica A; 2006, 109, 4-5; 561-564
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconductivity Study of GaN Highly Doped by Transition Metals
    Autorzy:
    Gosk, J.
    Boćkowski, M.
    Tokarczyk, M.
    Kowalski, G.
    Twardowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399142.pdf
    Data publikacji:
    2013-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.25.Ha
    74.70.-b
    74.25.Dw
    75.50.-y
    61.72.Dd
    81.10.Dn
    Opis:
    GaN:Cr and GaN:Fe single crystals as well as GaN:Mn micropowders highly doped by transition metals were grown to investigate low temperature superconductivity. Magnetic measurements revealed type I superconductivity with $T_{C} ≈ 6 K$ and $H_{C} ≈ 600 Oe$, identical for all compounds and also identical to that observed before in GaP:Cr and GaAs:Cr. The presence of amorphous inclusions of gallium may explain existing superconductivity as a result of a phase transition leading to β-Ga during cooling down of the sample. Since the observed parameters are close to those characteristic for superconducting Ga(II) this possibility could not be ruled out.
    Źródło:
    Acta Physica Polonica A; 2013, 124, 5; 877-880
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Majorana Fermions on Andreev Spectroscopy of Multiband Topological Superconductors
    Autorzy:
    Silva, A.
    Araújo, M.
    Sacramento, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/1402577.pdf
    Data publikacji:
    2015-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.10.Fd
    71.10.Pm
    71.10.Li
    73.20.-r
    74.45.+c
    74.20.Rp
    74.70.-b
    Opis:
    We introduce a model for a multiband topological superconductor with two orbitals per lattice site, in two spatial dimensions. Concentrating on the Andreev reflection problem, the appropriate wave function matching conditions for an interface with a normal single-band metal were previously derived in the framework of a quantum waveguide theory. This theory retrieves the correct number of Majorana fermion states as predicted by the topological index. We obtain the differential conductance as a function of bias voltage, which displays the contribution of the Majorana fermions. Interface disorder is also considered. By varying band structure parameters, topological transitions can be induced, whereby the number of the Majorana modes varies. We calculate the effect of such transitions on the differential conductance.
    Źródło:
    Acta Physica Polonica A; 2015, 128, 2; 210-212
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Phase Diagram and Activation Energy for Vortex Pinning in Nb/(Co,Pd) Superconductor-Ferromagnet Bilayer
    Autorzy:
    Syryanyy, Y.
    Aleszkiewicz, M.
    Cieplak, Marta
    Zhu, L.
    Chien, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/1374109.pdf
    Data publikacji:
    2014-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.25.F-
    74.25.N-
    74.25.Wx
    74.62.-c
    74.70.-b
    74.78.-w
    74.78.Fk
    75.70.Kw
    75.70.-i
    Opis:
    Using the magnetoresistance measurements we study the phase transition line and the activation energy for vortex pinning in superconductor/ferromagnet bilayer, built of a ferromagnetic Co/Pd multilayer with perpendicular magnetic anisotropy, and a niobium film, with insulating layer in-between to eliminate proximity effect. The domain width is reversibly pre-defined using the angle-dependent demagnetization. We find that the enhancement of the activation energy for vortex pinning by magnetic domains is rather modest, by a factor of about 2.1. We attribute this to large domain width, and large dispersion of the domain width in this bilayer.
    Źródło:
    Acta Physica Polonica A; 2014, 126, 4a; A-123-A-126
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transport Properties of Nitrided $VN-SiO_{2}$ Sol-Gel Derived Films
    Autorzy:
    Kościelska, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1431203.pdf
    Data publikacji:
    2012-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.20.Fw
    74.78.-w
    74.70.Ad
    Opis:
    This work presents transport properties of $xVN-(100-x)SiO_{2}$ (where x = 90, 80, 70, 60 mol%) films. The films were prepared by thermal nitridation of sol-gel derived $V_{2}O_{3}-SiO_{2}$ (in proper molar ratio) coatings. The coatings obtained by sol-gel method are especially suitable for the ammonolysis because of their porosity. The microporous structure allows both a significant incorporation of nitrogen and its distribution through the film. The nitridation process of $V_{2}O_{3}-SiO_{2}$ coatings leads to the formation of disordered structures, with VN metallic grains dispersed in the matrix of insulating $SiO_{2}$. The critical temperatures of the superconducting transition of the samples $T_\text{conset}$ are about 7.5 K.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 4; 744-746
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Point Contact Studies of High T$\text{}_{c}$ Superconductors
    Autorzy:
    Susła, B.
    Meepagala, S. C.
    Wolf, E. L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1929570.pdf
    Data publikacji:
    1993-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.50.+r
    74.70.Tx
    Opis:
    Point contact spectroscopy experiments were performed on both single crystals Bi$\text{}_{2}$Sr$\text{}_{2}$CaCu$\text{}_{2}$O$\text{}_{8+y}$ and BiSrCaCuO/Ag sintered material using gold tips. The spectra exhibit tunneling structure, which are interpreted in terms of the energy gap structure 2Δ = 58 meV at 4.2 K. We observed the strong Andreev reflection of the Au-BiSrCaCuO/Ag boundary.
    Źródło:
    Acta Physica Polonica A; 1993, 84, 2; 315-319
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Low Temperature STM/STS, Standard AFM and XPS οf Local $MgB_x$ Phases
    Autorzy:
    Strzelczyk, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1537268.pdf
    Data publikacji:
    2010-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.Ad
    74.78.-w
    68.37.Ef
    74.55.+v
    Opis:
    Low temperature scanning tunneling microscopy/ scanning tunneling spectroscopy, room temperature atomic force microscopy and X-ray photoelectron spectroscopy of the boron ions implanted into the magnesium substrate were performed in order to get information about the local superconducting behavior of thin $MgB_{x}$ film. Results confirm the island superconductivity far from the percolation threshold of the bulk superconducting MgB_2 sample.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 2; 417-419
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Influence of the Microwave Power on Josephson Microwave Absorption in High- Temperature Superconductors
    Autorzy:
    Czyżak, B.
    Stankowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1887983.pdf
    Data publikacji:
    1991-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.50.+r
    74.70.Vy
    Opis:
    The influence of the microwave power on the internal Josephson Junction System (JJS) in granular high T$\text{}_{c}$, superconductors was investigated using EPR methodology. Josephson Microwave Absorption signal was used to monitor local temperature of the Josephson Junction System while the bulk sample temperature was measured by a thermocouple. The effect of the JJS overheating is discussed as the consequence of an interaction between JJS, microwave field and the bulk sample.
    Źródło:
    Acta Physica Polonica A; 1991, 80, 1; 99-106
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconducting Properties of $NbN-SiO_2$ Sol-Gel Derived Thin Films
    Autorzy:
    Kościelska, B.
    Yuzephovich, O.
    Bengus, S.
    Witkowska, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1537127.pdf
    Data publikacji:
    2010-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.20.Fw
    74.78.-w
    74.70.Ad
    Opis:
    This work presents results of superconducting properties studies of $xNbN-(100-x)SiO_2$ (where x = 80 mol%) films of the thickness from 450 to 1950 nm. The films were prepared by thermal nitridation of sol-gel derived $xNb_2O_5-(100-x)SiO_2$ coatings. The nitridation process of $Nb_2O_5-SiO_2$ coatings leads to the formation of weakly disordered structures, with NbN metallic grains dispersed in the matrix of insulating $SiO_2$. All the samples in the normal state exhibit negative temperature coefficient of resistivity. Superconducting transition was not observed for the sample 450 nm thick. To examine the influence of magnetic field on superconducting properties of the films, the resistance versus temperature of 1350 and 1650 nm thick samples was measured in high magnetic fields. Resistive superconducting transitions are broadened due to the magnetic flux creep. The perpendicular upper critical magnetic fields for 1350 and 1650 thick samples are about 4.4 T. The critical temperatures of the superconducting transitions are about 4.5 K. Specific features of the magnetic field induced superconductor-insulator transition are found.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 2; 383-385
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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
    Artykuł
    Tytuł:
    Effect of van Hove Singularity on T$\text{}_{c}$ in Rb doped C$\text{}_{60}$
    Autorzy:
    Agrawal, B. K.
    Agrawal, S.
    Yadav, P. S.
    Srivastava, P.
    Srivastava, R.
    Singh, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035748.pdf
    Data publikacji:
    2003-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.25.Jb
    74.62.Fj
    74.70.Wz
    Opis:
    In the present study we investigate the role of van Hove singularity on the optimization of T$\text{}_{c}$ in Rb doped fullerenes C$\text{}_{60}$ Rb$\text{}_{3}$. A first principles self-consistent full potential linear muffin-tin orbital method using density functional theory in local density approximation was employed. The doped Rb atoms are of two types occupying the tetrahedral and interstitial positions in the fcc lattice. The added Rb atoms fill the t$\text{}_{1u}$ band of the undoped fullerenes C$\text{}_{60}$ up to half which makes C$\text{}_{60}$Rb$\text{}_{3}$ conducting. Saddle points leading to van Hove singularities are observed in the neighbourhood of the symmetry point L. The shifting of the van Hove singularity with the volume of the lattice is investigated. We observe a saddle point just at the Fermi level for a lattice constant of 14.435Å. The highest value of T$\text{}_{c}$ should thus be observed at the above lattice constant. This result is in excellent agreement with the observed high value of T$\text{}_{c}$ measured in C$\text{}_{60}$Rb$\text{}_{3}$ for a lattice constant of 14.435Å.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 5; 477-482
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Size Effect in Impedance of Nb$\text{}_{3}$Al Superconductor
    Autorzy:
    Aleksyeyev, P.
    Nabiałek, A.
    Vasiliev, S.
    Rusakov, V.
    Chabanenko, V.
    Zalutskii, M.
    Piechota, S.
    Szymczak, H.
    Kodess, B. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/2046746.pdf
    Data publikacji:
    2006-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.25.Qt
    74.70.Ad
    Opis:
    We present the results of the impedance measurements in Nb$\text{}_{3}$Al superconducting polycrystalline alloy vs. temperature and magnetic field. Using these results and applying the size effect model we calculate the flux-flow conductivity of the Nb$\text{}_{3}$Al superconducting alloy near its critical temperature.
    Źródło:
    Acta Physica Polonica A; 2006, 109, 4-5; 555-559
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of Pressure on the Size of Free Volumes in Some Waxes
    Autorzy:
    Zgardzińska, B.
    Gorgol, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1196483.pdf
    Data publikacji:
    2014-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.70.Bj
    81.30.Dz
    74.62.Fj
    Opis:
    Positron lifetime spectra were measured as a function of pressure for multicomponent mixtures of alkanes with an average carbon chain length of 19 atoms, and a varying width of length distribution. The range of rotator phase broadens with increasing the wax component distribution. When the number of wax components was five or more, we have observed the coexistence of rotator-rigid phases. The results of analysis of high statistics positron annihilation lifetime spectra by MELT program speaks in favour of an existence (in that range) of a single broad component, rather than two components corresponding to the separate rigid and rotator phases. In the mixtures of alkanes, the inter-lamellar gap size increases significantly due to the presence of various chain lengths of the components forming the mixture. For all investigated waxes the pressure of 360 MPa was sufficient to reduce the gap width to that one observed in pure alkanes.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 3; 816-820
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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
    Artykuł
    Tytuł:
    Gas Pressure Induced Porosity of CYTOP Polymer. A Positron Study
    Autorzy:
    Zgardzińska, B.
    Goworek, T.
    Śniegocka, M.
    Zaleski, R.
    Dlubek, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1339112.pdf
    Data publikacji:
    2014-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.70.Bj
    74.62.Fj
    Opis:
    The pore formation in CYTOP polymer under high pressure of argon or nitrogen gases was investigated by positron annihilation spectroscopy. In the range 0-70 MPa, formation of large open pores was observed. After reduction of pressure to normal one, the free volumes inside the polymer structure remained enlarged. The structure of CYTOP can be restored by applying the temperature over 470 K at normal pressure.
    Źródło:
    Acta Physica Polonica A; 2014, 125, 3; 782-784
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Aerogel IC3120 Under High Pressure Exerted Mechanically and by Nitrogen
    Autorzy:
    Gorgol, M.
    Zgardzińska, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/1033290.pdf
    Data publikacji:
    2017-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    78.70.Bj
    36.10.Dr
    61.43.Gt
    74.62.Fj
    Opis:
    Highly porous IC3120 silica aerogel was subjected to the high pressure up to 450 MPa while the positron annihilation lifetime spectra were collected. The pressure was delivered to the investigated samples in two ways: by pistons and by gas (nitrogen) penetrating the aerogel. The evolution of all PALS parameters was discussed. With the increase of the pressure, shortening of ortho-positronium lifetimes (different, depending on the pressure method introduced) was observed. Similarity between the dependence of the longest-lived o-Ps component lifetime on the pressure, for the sample affected with nitrogen molecules and pure nitrogen was observed. It suggests, that the nitrogen fills the largest free volumes of the aerogel. The pressure exerted mechanically causes much smaller decrease of free volume available for positronium. The comparison of PALS results with the electron microscopy images, obtained after removing the pressure, confirmed that more intense and lasting changes were caused by affecting the aerogel with the pistons.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 5; 1531-1534
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Superconducting Transition in Boron Doped Silicon Films
    Autorzy:
    Kociniewski, T.
    Débarre, D.
    Grockowiak, A.
    Kačmarčík, J.
    Marcenat, C.
    Bustarret, E.
    Ortega, L.
    Klein, T.
    Prudon, G.
    Dubois, C.
    Gautier, B.
    Dupuy, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1535297.pdf
    Data publikacji:
    2010-11
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.62.Dh
    73.61.Cw
    74.70.Ad
    Opis:
    We report on a detailed analysis of the superconducting properties of boron-doped silicon films grown along the 001 direction by gas immersion laser doping. This technique is proved to be a powerful technique to dope silicon in the alloying range 2-10 at.% where superconductivity occurs. The superconducting transitions are sharp and well defined both in resistivity and magnetic susceptibility. The variation of $T_{c}$ on the boron concentration is in contradiction with a classical exponential dependence on superconducting parameters. Electrical measurements were performed in magnetic field on the sample with $c_{B}$ = 8 at.% (400 laser shots) which has the highest $T_{c}$ (0.6 K). No hysteresis was found for the transitions in magnetic field, which is characteristic of a type-II superconductor. The corresponding upper critical field was on the order of 1000 G at low temperatures, much smaller than the value previously reported. The temperature dependence of $H_{c2}$ is very well reproduced by the linearized Gorkov equations neglecting spin effects in the very dirty limit. These measurements in magnetic field allow an estimation of the electronic mean-free path, the coherence length, and the London penetration depth within a simple two-band free electron model.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 5; 1026-1027
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optical and Electrical Noise Characteristics of Side Emitting LEDs
    Autorzy:
    Šaulys, B.
    Kornijčuk, V.
    Matukas, J.
    Palenskis, V.
    Pralgauskaitė, S.
    Glemža, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1506222.pdf
    Data publikacji:
    2011-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.70.+m
    74.40.-n
    85.60.Jb
    Opis:
    Low frequency noise characteristics of nitride based blue side emitting diodes have been investigated. It is shown that investigated devices distinguish by $1//f^α$-type optical and electrical fluctuations caused by various generation-recombination processes through defects formed generation-recombination centers. At higher frequencies optical shot noise due to random photon emission prevails $1//f^α$-type spectrum. The results have shown that low frequency optical and electrical noises are strongly correlated at small current region, but at higher forward current not correlated noise components dominate. Lenses and secondary optics of the investigated devices do not influence output light.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 2; 244-246
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fault Current Limitation by 2G HTS Superconducting Transformer - Experimental Investigation
    Autorzy:
    Wojtasiewicz, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398591.pdf
    Data publikacji:
    2016-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.90.+n
    84.70.+p
    84.71.-b
    85.25.-j
    85.25.Am
    85.25.Qc
    Opis:
    Transformers represent one of the oldest and most mature elements in a power transmission and distribution network. The new superconducting transformers are smaller and lighter than conventional ones and they have lower power losses, too. Also, the new 2G superconducting tapes with high resistivity in the normal state allow to build transformers with high short-circuit strength. The short-circuit current limiting feature of the superconducting transformer, which is the most important benefit of replacing conventional windings by superconducting ones, provides protection and significantly reduces the wear and tear of circuit breakers and other substation power equipment. This paper describes the design and experimental investigations results of a model of a 1-phase, 8.8 kVA superconducting transformer with windings made of 2G HTS tape. A special regard is given to the ability of the device's superconducting winding to limit the short-circuit current, in particular its equivalent resistance in normal state at a temperature of 77 K (i.e. resistance of the resistive layers of the HTS tape just after transition to the non-superconducting state).
    Źródło:
    Acta Physica Polonica A; 2016, 130, 2; 516-520
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Light-Emitting Diode Degradation and Low-Frequency Noise Characteristics
    Autorzy:
    Šaulys, B.
    Matukas, J.
    Palenskis, V.
    Pralgauskaitė, S.
    Kulikauskas, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/1505229.pdf
    Data publikacji:
    2011-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    72.70.+m
    74.40.-n
    85.30.-z
    85.60.Jb
    Opis:
    Comprehensive investigation of phosphide-based red and nitride-based blue light-emitting diodes characteristics and physical processes that take place in device structure during aging has been carried out. Analysis of noise characteristics (the emitting-light power and the LED voltage fluctuations, also their cross-correlation factor) shows that investigated LEDs degradation is caused by defects that lead to the leakage current and non-radiating recombination increase in the active region or its interfaces. Appearance of the defects first of all manifests in noise characteristics: intensive and strongly correlated $1//f^{α}$ type optical and electrical fluctuations come out.
    Źródło:
    Acta Physica Polonica A; 2011, 119, 4; 514-520
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Statistics of Tunneling Events in Three-Terminal Hybrid Devices with Quantum Dot
    Autorzy:
    Michałek, G.
    Bułka, B.
    Domański, T.
    Wysokiński, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1030466.pdf
    Data publikacji:
    2018-03
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.45.+c
    73.23.Hk
    72.70.+m
    73.63.Kv
    Opis:
    We investigate statistics of the tunneling events in the short time limit in terms of the waiting time distribution (WTD), defined as the probability for a delay time between two subsequent transitions of particles, and consider it for a quantum dot (QD) strongly coupled to a superconducting and weakly coupled to two normal electrodes. Our study focuses on the WTD in the subgap transport, when coherent exchange of the Cooper pairs occurs between the QD and the superconductor. The dynamics can be described in terms of a Markovian generalized master equation for the reduced density matrix. We observe coherent oscillations between the Andreev bound states in the correlated jumps, both for the local and non-local WTDs. In addition the analysis of the transient currents give us some insight into dominant relaxation processes in short time scales.
    Źródło:
    Acta Physica Polonica A; 2018, 133, 3; 391-393
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconductivity and Magnetism of $Dy_{1-x}Y_xRh_4B_4$: Candidate for Spin-Triplet Cooper Pairing
    Autorzy:
    Dmitriev, V.
    Zaleski, A.
    Khlybov, E.
    Rybaltchenko, L.
    Khristenko, E.
    Ishchenko, L.
    Terekhov, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1812277.pdf
    Data publikacji:
    2008-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.Ad
    Opis:
    In this work for the first time we give the evidence that compound $Dy_{1-x}Y_x Rh_4B_4$ with the tetragonal body-centered crystal structure $LuRu_4B_4$ is the ferrimagnetic at temperatures $T_{Cur}$<40 K, ferrimagnetic superconductor at $T_C$ <10 K and antiferromagnetic superconductor at $T_N$ <3 K. No reentrant behavior was found down to T = 0.32 K. For the first time by means of a method of microcontact spectroscopy of the Andreev reflection in point contact$ Ag-Dy_{0.8}Y_{0.2}Rh_4B_4$ the value and temperature and field dependences of superconducting gap parameter∆(T, H) in $Dy_{0.8}Y_{0.2}Rh_4B_4$ were determined. The value of the ratio 2∆(0)/k$T_C$ is about 4. Some unusual features of∆(T, H) dependences were observed, which give the evidence that the $Dy_{1-x}Y_xRh_4B_4$ is a candidate for spin-triplet Cooper pairing of charges with the parallel spins.
    Źródło:
    Acta Physica Polonica A; 2008, 114, 1; 83-90
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Superconducting Devices for Power Engineering
    Autorzy:
    Janowski, T.
    Kondratowicz-Kucewicz, B.
    Wojtasiewicz, G.
    Kozak, S.
    Kozak, J.
    Majka, M.
    Jaroszyński, L.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398596.pdf
    Data publikacji:
    2016-08
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.90.+n
    84.60.Ve
    84.70.+p
    84.71.-b
    84.71.Ba
    84.71.Mn
    85.25.-j
    85.25.Am
    85.25.Qc
    Opis:
    The paper presents the current state of research on superconducting devices for the electrical power system, i.e. transformers, fault-current limiters, and energy storages. In particular, it describes scientific achievements of the Laboratory of Superconducting Technologies of Electrotechnical Institute. The development of distributed and renewable energy sources, as well as the increasing number of receivers with low power factor will rise interest in superconducting fault-current limiters and superconducting transformers rated below 1 MVA. Previous studies were focused on the largest power transformers and highest current superconducting fault-current limiters. ReBCO coated conductors allow to build efficient superconducting AC devices. Superconducting tape of a layered structure (second generation HTS tape) enables the construction of transformer rated up to a few MVA without the usage of parallel conductors. Relatively high resistance of the tape in normal state allows to build fault-current limiters and fault-current limiting transformers. Superconducting transformers and superconducting fault-current limiters can help to increase connected power of distribution stations and thereby accelerate development of renewable energy sources.
    Źródło:
    Acta Physica Polonica A; 2016, 130, 2; 537-544
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    "Ridge" Fermi Surface Study in Metallic (R)Ba$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ (R = Y, Dy) and in Oxygen Deficient YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ by Positron Annihilation
    Autorzy:
    Hoffmann, L.
    Manuel, Α. A.
    Barbiellini, B.
    Peter, Μ.
    Shukla, A.
    Walker, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933509.pdf
    Data publikacji:
    1995-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.72.Jt
    74.72.Βk
    71.25.Ηc
    78.70.Bj
    Opis:
    We present a detailed positron 2D-ACAR measurements study of the "ridge" Fermi surface of (R)Ba$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ (R = Y, Dy) compared to full-potential linearized augmented plane wave and linear muffin-tin orbital calculations. From different 2D-ACAR projections measured in DyBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$, a 3D model of the momentum density of the ridge was established and is in good agreement with LMTO calculations of YΒa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7}$, confirming the description of the ridge Fermi surface by local density approximation calculations. The ridge is also studied in oxygen deficient YΒa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$. With growing δ, the ridge disappears without changing in width. This is consistent with full-potential linearized augmented plane wave calculations of YΒa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{6.5}$, and supports the phase separation model of Mesot et al.
    Źródło:
    Acta Physica Polonica A; 1995, 88, 1; 147-161
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fabrication and Characterization of Thin Films of the Organic Superconductor α$\text{}_{t}$-(BEDT-TTF)$\text{}_{2}$I$\text{}_{3}$
    Autorzy:
    Moldenhauer, J.
    Wachtel, H.
    Schweitzer, D.
    Gompf, B.
    Eisenmenger, W.
    Bele, P.
    Brunner, H.
    Keller, H. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933377.pdf
    Data publikacji:
    1995-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.Kn
    73.50.-h
    81.15.Gh
    Opis:
    α-(BEDT-TTF)$\text{}_{2}$I$\text{}_{3}$ is a quasi-two-dimensional organic metal with a metal-insulator phase transition at 135 K. Thermal treatment at about 80°C leads to the metallic system α$\text{}_{t}$-(BEDT-TTF)$\text{}_{2}$I$\text{}_{3}$, which becomes superconducting below 8 K. Thin films of the α-phase (thickness between 500 and 3000 Å) have been evaporated in high vacuum onto several substrates and characterized by means of X-ray diffraction, scanning electron microscopy, atomic force microscopy and low field microwave absorption. Depending on the temperature of the substrate and the evaporation rate, the films exhibit different degrees of microcrystallinity, which under certain conditions can be strongly reduced and a completely covering film can be obtained. X-ray diffraction spectra reveal a high orientation with the c-axis perpendicular to the substrate and as well the successful conversion into the α$\text{}_{t}$-phase by tempering. Scanning electron microscopy and atomic force microscopy investigations prove that the conversion takes place without reducing the mechanical quality of the films. Low-field microwave-absorption experiments show that the α$\text{}_{t}$-films become superconducting with an onset at 9 K.
    Źródło:
    Acta Physica Polonica A; 1995, 87, 4-5; 823-827
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    We krwi: Naruszenia integralności wizerunku papieża 2000–2020
    In Blood: Violations of the Integrity of the Pope’s Image 2000–2020
    Autorzy:
    Bednarek, Joanna B.
    Powiązania:
    https://bibliotekanauki.pl/articles/47231832.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Instytut Sztuki PAN
    Tematy:
    performans społeczny
    skandal
    kultura prawomocna
    tożsamość prawomocna
    religia
    papież
    Maurizio Cattelan
    Jerzy Kalina
    aborcja
    social performance
    scandal
    legitimate culture
    legitimate identity
    religion
    pope
    abortion
    Opis:
    Artykuł dotyczy dwóch performansów społecznych, jakimi były naruszenia integralności prac Maurizia Cattelana La Nona Ora (2000) oraz Jerzego Kaliny Zatrute źródło (2020). Korzystając z narzędzi analizy działań performatywnych, autorka szuka odpowiedzi na pytania: na czym polegała interwencja (działanie) i w czyim imieniu była dokonywana (cel). Korzystając z pojęć zaczerpniętych z prac Pierre’a Bourdieu i Manuela Castellsa, tłumaczy skandaliczny potencjał obu dzieł. Głównym kontekstem analizy jest wizerunek Jana Pawła II w kulturze polskiej i w przestrzeni publicznej; dodatkowy kontekst artykułu stanowi protest przeciwko zaostrzeniu prawa antyaborcyjnego (2020). Analiza odsłania mechanizm obu wydarzeń: dzieło sztuki zakłócało (2000) / reprezentowało (2020) porządek kultury prawomocnej, dlatego wywołało działania performatywne mające na celu obronę i utrzymanie (2000) / zakłócenie i zmianę (2020) status quo; w obu przypadkach doszło do naruszenia dominującego w przestrzeni dyskursywnej wizerunku Jana Pawła II (w roku 2000 – dzieło; w 2020 – performans aktywistek).
    This article discusses two social performances, namely the violations of the integrity of Maurizio Cattelan’s sculpture La Nona Ora (2000) and Jerzy Kalina’s installation Zatrute źródło [Poisoned Spring] (2020). Based on performance analysis, the author seeks to establish what the intervention (action) was about and on whose behalf it was undertaken (aim). Using concepts taken from the works of Pierre Bourdieu and Manuel Castells, she explains the scandal potential of both works. The main context of the analysis is the image of John Paul II in Polish culture and public space; an additional context is provided by the protest against the tightening of anti-abortion law (2020). The analysis reveals the mechanism of both events: the artwork disrupted (2000) / represented (2020) the order of legitimate culture, therefore it triggered performative actions aimed at defending and maintaining (2000) / disrupting and changing (2020) the status quo. In both cases, the dominant image of John Paul II in the discursive space was violated (in 2000 – by the artwork; in 2020 – by the performance of women activists). 
    Źródło:
    Pamiętnik Teatralny; 2021, 70, 2; 55-74
    0031-0522
    2658-2899
    Pojawia się w:
    Pamiętnik Teatralny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-48 z 48

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