scholarly journals New model of the pinning potential barrier in layered HTc superconductors

2016 ◽  
Vol 30 (31) ◽  
pp. 1650387 ◽  
Author(s):  
J. Sosnowski
Keyword(s):  
Critical Current ◽  
Potential Barrier ◽  
Transport Current ◽  
Fast Neutrons ◽  
Layered Superconductor ◽  
Geometrical Approach ◽  
New Model ◽  
Pinning Potential ◽  
Pancake Vortex ◽  
Htc Superconductors

New model of the pinning potential barrier in multilayered HTc superconductors is presented, based on geometrical approach to the capturing interaction of pancake-type vortices with nano-sized defects. Using the above model the transport current flow phenomena in these materials, especially the current–voltage characteristics and critical current density, have been considered. Details of theoretical analysis are given, including the derivation of basic mathematical equations describing the potential barrier as a function of transport current intensity and the initial position of captured pancake vortex. Computer simulation has been performed of the influence of transport current amplitude on the potential barrier height for various sizes of pinning centers and initial pancake vortex position as well as the influence of fast neutrons irradiation creating nano-sized defects on critical current of HTc layered superconductor.

HIGH CRITICAL CURRENT DENSITY IN NEUTRON-IRRADIATED BULK YBa2Cu3O7

1990 ◽  
Vol 04 (11) ◽  
pp. 703-712 ◽  
Author(s):  
P.H. HOR ◽  
Z.J. HUANG ◽  
L. GAO ◽  
R.L. MENG ◽  
Y.Y. XUE ◽  
...  
Keyword(s):  
External Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Thermal Annealing ◽  
Current Density ◽  
Fast Neutrons ◽  
High Critical Current Density ◽  
Pinning Potential

Bulk melt-textured YBa 2 Cu 3 O 7 irradiated by fast neutrons has been investigated. We observed: (1) a critical current density (Jc) determined magnetically at 77 K exceeds 5×105 A/cm 2 in 0.1 T, 2×105 A/cm 2 in 1 T, and 1.2×103 A/cm 2 in 5.0 T; (2) at 5 K, Jc is >2.1×107 A/cm 2 in 0.5 T, ~1.8×107 A/cm 2 at 1 T and >8×106 A/cm 2 in 5.0 T and (3) the Jc-anisotropy decreases rapidly with the external field (H), e.g. at 77 K, it becomes 1 at ~4.8 T with Jc ~3×103 A/cm 2. We also found that (1) such a Jc-enhancement is most effective in low H but less so in high H, (2) the enhancement is temperature independent at low H, (3) the pinning potential remains unchanged to within ~10% as Jc varies by a factor of 15, and (4) thermal annealing up to 600°C recovers the un-irradiated state. These results and their implications are presented and discussed.

Impact of the Magnetic Flux Penetrating Vortex Core on the Critical Current of the HTc Superconductors

2010 ◽  
Vol 670 ◽  
pp. 28-37
Author(s):  
Jacek Sosnowski
Keyword(s):  
Magnetic Flux ◽  
Critical Current ◽  
Vortex Core ◽  
Quantum Effect ◽  
Electromagnetic Properties ◽  
New Model ◽  
Magnetic Vortices ◽  
Center Edge ◽  
Pinning Center ◽  
Htc Superconductors

New model of the capturing vortices in the HTc superconductors is presented, describing their electromagnetic properties, such as the critical current of these materials. Critical current of the superconductors, such as HTc tapes is dependent on the magnitude of the interaction magnetic vortices with pinning centers. This is in fact quantum effect since the magnetic flux in vortices is quantized. Capturing the vortices on the normal state nano-sized inclusions should lead to the modification of the flux distribution in the vortex core depending on the vortex position in the respect to the pinning center edge. These effects are considered in the paper and their influence on the critical current of the HTc materials, basing on the new model of the pinning interaction.

Anisotropy of the Critical Current in Layered Superconductor

1991 ◽  
pp. 551-554
Author(s):  
Taichi Yamaguchi ◽  
Shin’ya Aoki ◽  
Kazunori Onabe ◽  
Naohiro Futaki ◽  
Nobuyuki Sadakata ◽  
...  
Keyword(s):  
Critical Current ◽  
Layered Superconductor

STRUCTURES AND PROPERTIES OF F-DOPED BI-SYSTEM SUPERCONDUCTORS

1992 ◽  
Vol 06 (15) ◽  
pp. 943-954 ◽  
Author(s):  
XIAOHUI GAO ◽  
JIE LI ◽  
DE GAO ◽  
GUODONG ZHENG ◽  
SAI GAO
Keyword(s):  
Critical Current ◽  
Potential Barrier ◽  
Flux Pinning ◽  
Hole Concentration ◽  
Superconducting Phase ◽  
Structures And Properties ◽  
Mechanism Of Superconductivity ◽  
Weak Linkage ◽  
Theoretical Results ◽  
Structure Properties

In this paper, the possibility of F entering the superconducting phase, its position and the structure properties of the superconductors, and the mechanism of superconductivity in F-doped Bi-systems are studied based on experimental and theoretical results. It has been found that, because the ΔT c is narrowed and [Formula: see text] raised, the T co of F-doped Bi-system superconductors increases obviously, with the highest T co at 118 K, that F has entered into the superconducting phase, that generally F can reduce the potential barrier of forming high-T c superconducting phase and improve the superconductivity of Bi-systems, but only if there exists certain amount of Pb in the system, and that with F-doping the weak linkage of superconductor is decreased, the flux pinning is enhanced, the carrier-hole concentration is increased, and the critical current is improved.

Irradiation Defect Structures In YBa2Cu3O7-xand their Correlation with Superconducting Properties

1990 ◽  
Vol 209 ◽  
Author(s):  
Marquis A. Kirk
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Critical Current ◽  
Neutron Irradiation ◽  
Current Density ◽  
Amorphous Material ◽  
Amorphous Structure ◽  
Fast Neutrons ◽  
High Fluences ◽  
Defect Microstructures

ABSTRACTWe review our work on irradiation effects in single crystal YBa2Cu3O7-x. Transmission electron microscopy has been employed to study the defect microstructures produced by irradiations with fast neutrons, MeV ions (Kr, Ne and p), and electrons. The atomic structure within defect cascades was investigated using 50 keV Kr and Xe ion irradiations to low doses. Evidence is shown for an amorphous structure with some incoherent recrystallization within individual cascades. Correlation with enhancements in critical current density produced by neutron irradiations suggest that this cascade structure effectively pins magnetic flux lines.At sufficiently high fluences of fast neutrons or MeV Kr and Ne ions, a cellular microstructure is found. This structure consists of cells or microcrystallites of good crystalline and superconducting material (in the case of neutron irradiation), with cell walls of amorphous material. Full amorphization proceeds with the growth of cell wall volume. The formation of this microstructure coincides with a decrease in critical transport current, but is not observed by magnetization measurements.Increases in critical current density under proton irradiation, comparable to those produced by neutron irradiation, have been reported. The defect structure produced by proton irradiations is examined here and found to differ from that of neutron irradiations. The structure is suggested to be consistent with the clustering of mobile defects (at 300 K) produced by the lower energy recoils which dominate in proton irradiations. In both the proton and fast neutron irradiations, to fluences producing the maximum enhancements in critical current densities, the degradations in critical temperature are not severe, <10 K.Our most recent measurements of changes in critical temperature and current density, and defect microstructure following electron irradiations will be described

scholarly journals Intergranular pinning potential and critical current in the magnetic superconductorRuSr2Gd1.5Ce0.5Cu2O10

2005 ◽  
Vol 71 (6) ◽  
Author(s):  
M. G. das Virgens ◽  
S. García ◽  
M. A. Continentino ◽  
L. Ghivelder
Keyword(s):  
Critical Current ◽  
Pinning Potential

scholarly journals Критический ток в длинном джозефсоновском контакте во внешнем магнитном поле при слабом пиннинге

2022 ◽  
Vol 92 (3) ◽  
pp. 414
Author(s):  
М.А. Зеликман
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Critical Current ◽  
Critical Value ◽  
Transport Current ◽  
Entire Length ◽  
Gibbs Potential ◽  
Potential Reduction ◽  
The Magnetic Field ◽  
Josephson Contact

The analysis of possible current distributions when passing current through a periodically modulated long Josephson contact located in an external magnetic field is carried out. An approach based on the analysis of continuous configuration modification proceeding in the direction of Gibbs potential reduction is used for the calculation. The case when the pinning parameter is less than the critical value is considered. It is shown that at any value of the external magnetic field, there is a critical value of the transport current, when exceeded, the situation ceases to be stationary, as a result of which energy passes into radiation and heat, i.e. currents cease to be persistent. The value of the critical current is determined by the value of the magnetic field at which the vortices begin to fill the entire length of the contact. With an increase in the external magnetic field, the critical value of the current decreases.

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