scholarly journals Inductive Measurement of the Magnetic-Field Angular Dependent Critical Current Densities and n-values in High-Temperature Superconducting Thin Films and Coated Conductors using Third-Harmonic Voltages

2014 ◽  
Vol 49 (9) ◽  
pp. 494-499
Author(s):  
Hirofumi YAMASAKI ◽  
Mitsuho FURUSE
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
High Temperature ◽  
Critical Current ◽  
Coated Conductors ◽  
Superconducting Thin Films ◽  
Third Harmonic ◽  
Current Densities ◽  
Inductive Measurement ◽  
The Magnetic Field

Relationship between critical current properties and nanorod morphology in REBa2Cu3Oy thin films

2012 ◽  
Vol 1434 ◽  
Author(s):  
M. Haruta ◽  
N. Fujita ◽  
Y. Ogura ◽  
T. Nakata ◽  
T. Maeda ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Fields ◽  
Critical Current ◽  
Growth Temperature ◽  
Coated Conductors ◽  
Laser Source ◽  
Bose Glass ◽  
Current Densities ◽  
Irreversibility Lines

ABSTRACTChanges in critical current properties depending on growth temperature (Ts) were clarified for Ba-Nb-O-doped YBa2Cu3Oy (Y123) films deposited by YAG- and excimer-PLD. Due to the introduction of Ba-Nb-O-nanorods, a vortex-Bose-glass-like behavior emerged as irreversibility lines and in-field critical current densities (Jcs) were improved. Crossover magnetic fields (Bcr) and in-field Jcs increased with the increase in Ts for the Y123 films with nanorods. These Ts-dependent critical current properties were attributable to the changes in morphology of the nanorods with Ts and were independent of laser source in PLD apparatuses. For the fabrication of RE123 coated conductors containing nanorods, optimization of Ts with taking both materials of RE123 matrix and nanorod into account is necessary to achieve higher in-field Jc.

scholarly journals Continuum sensitivity and design optimization of superconducting systems under critical current densities with magnetic field dependence

2021 ◽  
Author(s):  
Kyungsik Seo ◽  
Tim Coombs ◽  
Il Han Park
Keyword(s):  
Magnetic Field ◽  
Design Optimization ◽  
Critical Current ◽  
Current Density ◽  
State Equation ◽  
Design Sensitivity ◽  
Continuum Sensitivity ◽  
Current Densities ◽  
The Magnetic Field ◽  
The Continuum

AbstractThis paper presents an approach for deriving the continuum sensitivity of superconducting systems operating at critical current densities and an optimization method based on the continuum sensitivity. In the sensitivity problem, the superconducting systems is represented by a variational state equation, wherein the magnetic permeability depends on the magnetic field, which is transformed from a state equation with a field-dependent source. The design sensitivity is derived using the material derivative concept of continuum mechanics and the adjoint variable method. The adjoint system has a material property represented as a symmetric tensor that contains the sensitivity of the current density with respect to the magnetic field. The design sensitivity is represented in the analytical form of a surface integral on the interface between the superconducting material and its surroundings, which depends on the sensitivity of the current density. The optimization scheme is constructed based on the continuum design sensitivity. In the design optimization, the level set method is used to express the shape variation of the superconducting materials. The numerical example of infinite solenoids demonstrates that the design sensitivity provides an accurate design solution considering the critical current condition. In addition, the design example of a magnetic resonance imaging solenoid shows that the derived design sensitivity has the inherent ability for attaining the compact design by treating the input current of a superconducting system as a critical condition.

scholarly journals Механизм формирования критического тока высокотемпературных сверхпроводников, содержащих сквозные микроскопические дефекты

2021 ◽  
Vol 63 (1) ◽  
pp. 65
Author(s):  
А.Н. Максимова ◽  
В.А. Кашурников ◽  
А.Н. Мороз ◽  
И.А. Руднев
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Magnetic Flux ◽  
Critical Current ◽  
High Temperature Superconductor ◽  
Physical Mechanism ◽  
Characteristic Size ◽  
Pinning Centers ◽  
The Magnetic Field ◽  
Qualitative Picture

The critical current of a model high-temperature superconductor (HTSC) with defects in the form of through holes (antidots) with a characteristic size greater than or of the order of the penetration depth of the magnetic field is calculated. To do this, the subprocesses equivalent to the trapping of the magnetic flux by the hole and the creation of a vortex at the edge of the hole are introduced into the model of layered HTSC. It is shown that accounting for these subprocesses leads to the appearance of a physical mechanism that allows us to correctly describe the non-monotonic dependence of the critical current on the characteristic size of the antidot, similar to that observed in the experiment. Calculations were performed for a pure superconductor and a superconductor containing nanoscale pinning centers. It is shown that the presence of nanoscale pinning centers along with antipoints does not change the qualitative picture of the influence of the antidot radius on the pinning character of the magnetic flux and the behavior of the critical current in the HTSC.

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