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Wyszukujesz frazę "Andrzejewski" wg kryterium: Wszystkie pola


Tytuł:
Upper Critical Field for Cobalt Oxide Superconductors
Autorzy:
Mierzejewski, M.
Maśka, M.
Andrzejewski, B.
Powiązania:
https://bibliotekanauki.pl/articles/2038388.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Op
74.20.Rp
Opis:
Motivated by the recent discovery of the cobalt oxide superconductors, we calculate the temperature dependence of the upper critical field on a triangular lattice. Using the lattice version of the Gor'kov equations we investigate how the applied magnetic field affects singlet and triplet types of superconductivity. We show that in a wide range of model parameters not only Zeeman coupling, but also the diamagnetic pair breaking mechanism favors the triplet pairing. In the cobalt oxide superconductors the symmetry of the order parameter remains an open problem and both singlet and triplet superconductivity should be taken into account. We show that in such a case, an external magnetic field may induce a transition from singlet to triplet superconductivity. We discuss experimental results which may confirm this tempting hypothesis.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 603-608
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic structure calculations of InP-based coupled quantum dot-quantum well structures
Autorzy:
Andrzejewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1160527.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.21.Fg
73.22.Dj
74.50.+r
Opis:
In this work we investigate the electronic structure of coupled 0D-2D nanostructures. The respective confined state energy levels in a quantum dot-quantum well system are calculated for various conduction band offsets - between the quantum dot and surrounding material. The calculated electron and hole energy levels with their wave functions allow determining if the wave functions are within the injector quantum well or within the quantum dot and if the carrier positions on the energy scale are appropriate from the point of view of a possible laser structure utilizing the so-called tunnel injection scheme. It is shown that for an adequate width of an injector quantum well and the conduction band offsets designing an optimal tunnel injection structure is possible.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-97-A-99
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of YBCO-PST Composites
Autorzy:
Andrzejewski, B.
Kaczmarek, A.
Stankowski, J.
Hilczer, B.
Marfaing, J.
Régnier, S.
Caranoni, C.
Powiązania:
https://bibliotekanauki.pl/articles/2014556.pdf
Data publikacji:
2000-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.80.Bj
74.25.Ha
76.30.Fc
Opis:
The magnetic properties of granular superconductor-insulator composites were investigated. The composites were random composition of the YBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ (YBCO) high-temperature superconductor and Pb(Sc$\text{}_{0.5}$Ta$\text{}_{0.5}$)O$\text{}_{3}$ (PST) ferroelectric insulator. The composites exhibited lower superconducting volume ratio than the YBCO content. For samples with YBCO content low enough no global (the whole sample) and local (separated grains) superconductivity was observed. The observed decay of the superconductivity, lowering of the critical temperature, and the increase in number of paramagnetic centres as PST content increases are explained assuming reaction among YBCO and PST phases and possible formation of an additional ones, which did not exist in the initial powders.
Źródło:
Acta Physica Polonica A; 2000, 98, 6; 739-746
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties of Bismuth Ferrite Nanopowder Obtained by Mechanochemical Synthesis
Autorzy:
Szafraniak-Wiza, I.
Andrzejewski, B.
Hilczer, B.
Powiązania:
https://bibliotekanauki.pl/articles/1375623.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Bc
81.07.Wx
81.20.Ev
75.85.+t
Opis:
Multiferroic bismuth ferrite $(BiFeO_{3})$ nanopowders have been obtained at room temperature by mechanochemical synthesis. Depending on the post-synthesis processing the nanopowders exhibited differences in the mean sizes, presence of amorphous layer and/or secondary phases. Extended magnetic study performed for fresh, annealed and hot-pressed nanopowders revealed substantial improvement of the magnetic properties in the as-prepared powder.
Źródło:
Acta Physica Polonica A; 2014, 126, 4; 1029-1031
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relation between Structure and Magnetic Properties of Microstructured $PrAlO_3$
Autorzy:
Andrzejewski, B.
Pawlak, D.
Klimczuk, T.
Turczyński, S.
Powiązania:
https://bibliotekanauki.pl/articles/1429107.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.Ej
71.70.Ej
75.50.-y
75.70.Tj
Opis:
The magnetic properties of both the praseodymium-aluminium perovskite $PrAlO_3$ crystal and its microstructured version in the form of a $PrAlO_3-PrAl_{11}O_{18}$ eutectic have been investigated. It is shown that R\overline{3}c → Imma 205 K first-order and Imma → C 2/m near 150 K second-order phase transitions in a $PrAlO_3$ single crystal are suppressed after structuring the material and embedding it in a $PrAl_{11}O_{18}$ matrix. This behavior is related to the $PrAl_{11}O_{18}$ matrix, which mechanically hinders expansion of the microrods and in this way suppresses the phase transitions.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1315-1317
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Capacity and Susceptibility of $CeCu_4Al$
Autorzy:
Reiffers, M.
Gažo, E.
Timko, M.
Kowalczyk, A.
Toliński, T.
Andrzejewski, B.
Šebek, J.
Šantavá, E.
Powiązania:
https://bibliotekanauki.pl/articles/1813775.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.30.Mb
Opis:
The heat capacity in the applied magnetic field up to 9 T, susceptibility and magnetization of polycrystalline $CeCu_4Al$ are presented. The determined electronic heat capacity coefficient γ= 210 mJ $mol^{-1} K^{-2}$ confirmed heavy fermion character of this compound. Magnetic ordering was not observed down to 0.5 K. Magnetic properties confirm these observations.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 425-428
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:
New Numerical Matrix Methods of Solving the Quasi-One-Dimensional Effective-Mass Equation
Autorzy:
Salejda, W.
Tyc, M. H.
Andrzejewski, J.
Kubisa, M.
Misiewicz, J.
Just, M.
Ryczko, K.
Powiązania:
https://bibliotekanauki.pl/articles/2008323.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Bf
73.20.Dx
Opis:
New efficient numerical methods of computing eigenvalues and eigenvectors of quasi-one-dimensional effective-mass Hamiltonian with arbitrary coordinate dependence of charge carrier mass are presented. Within the proposed approach the effective-mass equation is replaced by a nonsymmetric or symmetric matrix eigenproblem which can be analysed numerically with the help of existing computer routines. The presented methods are verified in special semiconductor heterostructure cases that are solvable within other approaches. A generalization of the presented methods for nonparabolic materials is also discussed.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 881-896
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:
Effect of Nd³⁺ doping on magnetic and dielectric properties of SrFe₁₂O₁₉ hexaferrite synthesized by coprecipitation method
Autorzy:
Hilczer, A.
Pasińska, K.
Markiewicz, E.
Pietraszko, A.
Andrzejewski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1047614.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.60.Ej
75.75.+a
81.20.Fw
Opis:
Magnetic and dielectric properties of hexagonal ferrites important for applications in microwave absorbers are strongly determined by the processing conditions. We studied dielectric and magnetic response of Sr_{1-x}Nd_{x}Fe₁₂O₁₉ (x=0, 0.03, 0.05, 0.07, 0.09) solid solutions obtained by coprecipitation method. The structure of the samples was controlled by X-ray diffraction and scanning electron microscope images revealed that the powder is a mixture of small nanograins and crystallites of 500 nm-1 μm in size. Nd³⁺ doping was found to result in an increase in the coercive field which we would like to relate to the domain wall pinning. The doping-induced changes are monotonous with x up to 0.07. The observed dispersion of permittivity was found to be correlated with the frequency behaviour of electric conductivity of the samples.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 669-672
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:
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:
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:
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

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