Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 6

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  superconductivity
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Structure and properties of solid solutions in the Mg-Al-B system

100%
Sevastyanova L., Gulish O., Stupnikov V., Genchel V., Kravchenko O., Bulychev B., Lunin R., Tarasov V.
Open Physics
|
2012
|
vol. 10
|
issue 1
189-196
EN
Compounds with the general formula Mg1−x AlxB2 were obtained by two-step ceramic synthesis. All compounds were characterized by X-ray diffraction, NMR spectroscopy, and by four point probe resistivity measurements in various magnetic fields method. The diborides unit cell parameters were determined as a function of the Al mole fraction. With the vaues of x up to 0.40 (where x is the composition of the stock prepared for sintering), the unit cell parameters of Mg1−x AlxB2 are similar to those of pure MgB2 and the superconducting transition temperature was lowered. For stock compositions of 0:25 ≤ x ≤ 0:60, the products contain a superstructure, also superconducting phase, which becomes the only product at x = 0:50, and at x > 0:60 this phase is replaced by AlB2-based solid solutions.
2
Content available remote

The dependence of critical temperature on oxygen concentration in YBa2Cu3O6+x in terms of the fragmented chain model

100%
Milic M., Matic V., Lazarov N.
Open Physics
|
2011
|
vol. 9
|
issue 3
690-697
EN
An extended ASYNNNI model, that beside nearest-neighbour and next-nearest neighbour O-O interactions in the basal plane also includes interactions between the three nearest oxygen atoms, is used to describe the statistics of CuO chain fragmentation and to calculate doping and T c in YBa2Cu3O6+x . Calculations were made by the Monte Carlo method employing the recently proposed charge transfer model that assumes only chains whose length is equal to, or exceeds, a characteristic (critical) length, l cr, can provide holes to the layers and contribute to doping p. The obtained p(x) is then combined with a universal T c versus p relation to yield T c(x) characteristics that correlate remarkably with those reported in recent experiments. The best coordination between theoretical and experimental T c(x) characteristics has been achieved for l cr = 2, implying that only isolated basal plane oxygen atoms (trivial chains) do not contribute holes to CuO2 layers.
3
Content available remote

Chemical Substitution and High Pressure Effects on Superconductivity in the LnOBiS2(Ln = La-Nd) System

100%
Fang Y., Wolowiec C. T., Yazici D., Maple M. B.
Novel Superconducting Materials
|
2015
|
vol. 1
|
issue 1
EN
A large number of compounds which contain BiS2 layers exhibit enhanced superconductivity upon electron doping. Much interest and research effort has been focused on BiS2-based compounds which provide new opportunities for exploring the nature of superconductivity. Important to the study of BiS2-based superconductors is the relation between structure and superconductivity. By modifying either the superconducting BiS2 layers or the blocking layers in these layered compounds, one can effectively tune the lattice parameters, local atomic environment, electronic structure, and other physical properties of these materials. In this article, we will review some of the recent progress on research of the effects of chemical substitution in BiS2-based compounds, with special attention given to the compounds in the LnOBiS2 (Ln = La-Nd) system. Strategieswhich are reported to be essential in optimizing superconductivity of these materials will also be discussed.
4
Content available remote

Application of Intrinsic Quantized Flux of Electrons and Holes in Josephson Junctions

100%
Saglam Z., Boyacioglu B.
Acta Physica Polonica A
|
2018
|
vol. 133
|
issue 5
1129-1132
EN
The aim of this study is to investigate the influence of spin degrees of freedom on the flux quantization in a 2D Josephson junction. One of the most important properties of the Josephson structures is the total quantum flux which can be related to the phase difference across the junction. For example the sign of the phase difference controls the direction of the Josephson current while the magnitude of the phase difference affect the critical current itself. So far in literature to calculate the total quantum flux in the Josephson structures only the flux of the external magnetic field (and hence the external vector potential) has been considered but the intrinsic quantum flux of correlated electrons and holes have not been taken into account. We have recently calculated the intrinsic quantized magnetic flux of electrons and holes. We showed that depending on the spin orientations, the spin contribution to the quantized intrinsic flux of a correlated electron is equal to (Φ_{int}=±(g*Φ_{0})/2). Here g* is the effective Landé g-factor and Φ_{0} is the unit of flux (fluxoid). In the present study we calculate the above mentioned phase differences across the junction considering the intrinsic quantum flux of electrons and holes. For electrons the additional flux contribution will be: ΔΦ_{int}=±(g_{e}*Φ_{0})/2 and for holes, the related contribution will be: ΔΦ_{int}=±(g_{h}*Φ_{0})/2. We show that, for both charge carriers, the effective Landé g-factors (g_{e}*,g_{h}*), take only even integer values such as (0,2,4,...). The present calculations can be easily extended to the intrinsic Josephson junctions as well. We found that flux contribution to the total flux due to spin is very important and it is in fact ±Φ_{0}/2 depending on the spin up and down cases or the ground state.
5
Content available remote

Superconductivity in covalent semiconductors

88%
Iakoubovskii K.
Open Physics
|
2009
|
vol. 7
|
issue 4
654-662
EN
This review covers recent advances in superconductivity of diamond, Si, SiC, group III–V and II–IV semiconductors, metal-intercalated graphite and fullerites. The results are critically analyzed and prospects are given for future research directions. In particular, it is argued that the highest transition temperatures of ∼9 K in diamond and 11.5 K in CaC6 can further be enhanced and that no reliable evidence exists yet for superconductivity in III-V semiconductors.
6
Publication available in full text mode
Content available

Numerical assessment of thermal behaviour of a superconducting bus-bar with a Nuclotron-type cable

75%
Tomków Ł., Cholewiński M., Ciszek M., Chorowski M., Tomków Ł., Cholewiński M., Ciszek M., Chorowski M.
|
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.