JOSEPHSON JUNCTIONS IN SINGLE-CRYSTAL YBa2Cu3O7

1988 ◽  
Vol 02 (05) ◽  
pp. 1113-1120
Author(s):  
A. G. Lebed
Keyword(s):  
Magnetic Field ◽  
Boundary Condition ◽  
Josephson Junctions ◽  
Positive Curvature ◽  
Epitaxial Films ◽  
High Tc Superconductors ◽  
Characteristic Distance ◽  
High Tc ◽  
Surface Superconductivity ◽  
The Magnetic Field

It's shown, that I − V characteristics of the epitaxial films[1] and unusual magnetic properties of the single crystals[2] may be attributed to the forming on the defects of the plural Josephson junctions. We have given the estimations of the dielectric gap, of the transparence of the corresponding energy barriers and the characteristic distance between them. It's studied the surface superconductivity in the magnetic field. We have marked, that non-trivial boundary condition for High-Tc superconductors[3] lead to the positive curvature on dependence Hc 3 (T) .

A model for the texture development of high-Tc superconductors under an elevated magnetic field

1999 ◽  
Vol 14 (7) ◽  
pp. 2751-2763 ◽  
Author(s):  
P. J. Ferreira ◽  
H. B. Liu ◽  
J. B. Vander Sande
Keyword(s):  
Magnetic Field ◽  
Theoretical Model ◽  
Melt Processing ◽  
High Tc Superconductors ◽  
High Tc ◽  
Grain Alignment ◽  
Grain Rotation ◽  
Stages Of Growth ◽  
Intermediate States ◽  
The Magnetic Field

A theoretical model is proposed to explain the degree of texture achieved in high-Tc superconductors during melt-processing under an elevated magnetic field. The degree of grain alignment is quantified through a factor F which is defined as ranging from 0 (random alignment) to 1 (completely oriented). Intermediate values of F clearly characterize intermediate states of alignment in which there is still some tendency for the grains to align their c axes with the magnetic field. The model suggests that the enhancement in texture is primarily obtained through grain rotation during the early stages of grain growth from the liquid. At the later stages of growth, grains interact with each other, which hinders the phenomena of magnetic-field–induced grain alignment.

PRESSURE EFFECTS ON HIGH-Tc SUPERCONDUCTORS CURRENT TRANSFER

1991 ◽  
Vol 05 (20) ◽  
pp. 3255-3265 ◽  
Author(s):  
V.M. SVISTUNOV ◽  
A.I. D’YACHENKO ◽  
V. YU. TARENKOV
Keyword(s):  
Magnetic Field ◽  
High Pressure ◽  
Magnetic Fields ◽  
Pressure Effects ◽  
High Magnetic Fields ◽  
Magnetic Field Direction ◽  
Current Transfer ◽  
High Tc Superconductors ◽  
High Tc ◽  
The Magnetic Field

The efficiency of high pressure technique for the evidence of the Josephson nature of the intergranular contacts in metal ceramics has been demonstrated. With this technique it has been found that the abnormal hysteresis in fields of the order of tens kOe was not connected with the short-circuited contacts between the granules. The reason for the hysteresis lies in the ambiguity of the magnetization of the granules versus the change in the magnetic field direction. The critical current stability of the Josephson conteacts to high magnetic fields is due to both the inhomogeneity of the contacts and the existence of Abrikosov vortices within the superconducting electrode links.

Phase slippage in a magnetic field at intra- and intergranular Josephson junctions in high-Tc superconductors

1990 ◽  
Vol 170 (3-4) ◽  
pp. 222-230 ◽  
Author(s):  
G.B. Smith ◽  
K.-H. Müller ◽  
C. Andrikidis ◽  
S.W. Filipczuk ◽  
J.M. Bell ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Josephson Junctions ◽  
High Tc Superconductors ◽  
High Tc ◽  
Phase Slippage

Magnet Replica by High Tc Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
R. Weinstein ◽  
In-Gann Chen ◽  
J. Liu ◽  
D. Parks
Keyword(s):  
Magnetic Field ◽  
Liquid Phase ◽  
Uniform Magnetic Field ◽  
Field Trapping ◽  
High Tc Superconductors ◽  
High Tc ◽  
Large Magnetic Field ◽  
The Magnetic Field

AbstractA study of magnetic field trapping phenomenon in oriented grain YBa2Cu3O7‐x samples produced by liquid phase processing has been conducted. The magnetic field reproduced from the parent magnetic field allows the production of “magnet replicas”, which can be used in various instruments when large magnetic field is needed constant in time. This paper reports the magnetic field trapping capability and uniformity observed in these oriented grain samples. The feasibility of building large and uniform magnetic field by assembling small SC specimens has also been explored.

Modelling of Hysteresis of High-Tc Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 2958-2961
Author(s):  
I. Vajda ◽  
A. Szalay ◽  
L. Mohácsi ◽  
J. Lukács ◽  
T. Porjesz
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Physical Modelling ◽  
Computer Code ◽  
Two Dimensional ◽  
Magnetization Curves ◽  
High Tc Superconductors ◽  
High Tc ◽  
Basic Ideas ◽  
The Magnetic Field

For the numerical calculation of the magnetic field and forces between HTSC materials and permanent magnets an algorithm and a two-dimensional finite difference computer code has been developed. The superconductor has been treated with its nonlinear and anisotropic dc magnetization curve. The magnetization curves are used as input characteristics for the field calculations. The basic ideas of the physical modelling are discussed.

MAGNETIC PHASES OF JOSEPHSON VORTEX IN STRONGLY ANISOTROPIC High-Tc SUPERCONDUCTORS

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3357-3363
Author(s):  
KAZUTO HIRATA
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Flow Resistance ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Josephson Vortex ◽  
High Tc Superconductors ◽  
High Tc ◽  
The Magnetic Field ◽  
Ordered State

When a magnetic field is applied parallel to the superconducting layers in high-Tc superconductors (HTSCs), vortices become Josphson vortices (JVs). To study the magnetic phase diagram of JVs in strongly anisotropic HTSCs, we propose that the JV flow-resistance measurement is a powerful probe to observe periodic oscillations in the JV flow-resistance against the magnetic field. We could determine the magnetic phase diagram of JVs in Bi -2212, in which there exist a three-dimensionally-ordered state and a two-dimensionally quasi-ordered one.

Enhancing Superconducting Parameters by Array of External Magnetic Dots

2009 ◽  
Vol 1180 ◽  
Author(s):  
Wei Jiang Yeh ◽  
Bo Cheng
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Pinning Force ◽  
High Tc Superconductors ◽  
High Tc ◽  
Current Value ◽  
Magnetic Dots ◽  
The Magnetic Field ◽  
Superconducting Parameters

AbstractEnhancing the pinning force in high-Tc superconductors can be achieved by externally introduced periodic magnetic dots. We use a novel nano-technique to deposit periodic sub-micon Ni dots on YBa2Cu3O7 thin films. The current versus voltage characteristics of an YBa2Cu3O7 thin film strip with uniform Ni dots are measured at various temperatures and magnetic fields. They are compared with the current versus voltage characteristics of a bare YBa2Cu3O7 thin film strip without magnetic dots. It is found the critical current value of the strip with Ni dots reduces with a much slower pace as the magnetic field strength increases in comparison with the value of the bare sample.

scholarly journals Modification of Critical Current Density Anisotropy in High-Tc Superconductors by Using Heavy-Ion Irradiations

2021 ◽  
Vol 5 (2) ◽  
pp. 16
Author(s):  
Tetsuro Sueyoshi
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
High Tc Superconductors ◽  
High Tc ◽  
Heavy Ion Irradiation ◽  
The Magnetic Field

The critical current density Jc, which is a maximum value of zero-resistivity current density, is required to exhibit not only larger value but also lower anisotropy in a magnetic field B for applications of high-Tc superconductors. Heavy-ion irradiation introduces nanometer-scale irradiation tracks, i.e., columnar defects (CDs) into high-Tc superconducting materials, which can modify both the absolute value and the anisotropy of Jc in a controlled manner: the unique structures of CDs, which significantly affect the Jc properties, are engineered by adjusting the irradiation conditions such as the irradiation energy and the incident direction. This paper reviews the modifications of the Jc anisotropy in high-Tc superconductors using CDs installed by heavy-ion irradiations. The direction-dispersion of CDs, which is tuned by the combination of the plural irradiation directions, can provide a variety of the magnetic field angular variations of Jc in high-Tc superconductors: CDs crossing at ±θi relative to the c-axis of YBa2Cu3Oy films induce a broad peak of Jc centered at B || c for θi < ±45°, whereas the crossing angle of θi ≥ ±45° cause not a Jc peak centered at B || c but two peaks of Jc at the irradiation angles. The anisotropy of Jc can also modified by tuning the continuity of CDs: short segmented CDs formed by heavy-ion irradiation with relatively low energy are more effective to improve Jc in a wide magnetic field angular region. The modifications of the Jc anisotropy are discussed on the basis of both structures of CDs and flux line structures depending on the magnetic field directions.

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