scholarly journals Doubling the critical current density of high temperature superconducting coated conductors through proton irradiation

2013 ◽  
Vol 103 (12) ◽  
pp. 122601 ◽  
Author(s):  
Y. Jia ◽  
M. LeRoux ◽  
D. J. Miller ◽  
J. G. Wen ◽  
W. K. Kwok ◽  
...  
2017 ◽  
Vol 5 (1) ◽  
pp. 69
Author(s):  
Soh Deawha ◽  
N. Korobova ◽  
Park Jungcheul

<p>High temperature superconducting (HTS) thick films deposited on metal Ag wire were prepared with YBCO and BSCCO powders by electrophoretic deposition method. I<sub>2</sub> was used as additives for surface charge of YBCO and BSCCO particles. When 2-3 wt.% BaF<sub>2</sub> was added in the YBCO suspension, the pores and cracks of film surface were decreased and film density could be increased. In case of YBCO films, the critical current density (J<sub>c</sub>) was calculated at the value of 1458 A/cm<sup>2</sup> (77 K, 0 K) by 4 point prove method. BSCCO films had less cracks than YBCO films, and the critical current density (J<sub>c</sub>) was obtained more than 10<sup>4</sup> A/cm<sup>2</sup>.</p>


Author(s):  
Shinichi Ishiguri ◽  
Shotaro Tawara

In the present work, a superlattice structure comprising superconducting and insulator layers is studied. Here, if a magnetic field is applied parallel to the layers, the lack of a pinning center leads to a novel transition; in particular, as the applied magnetic field is reduced, the stationary wave surrounding the magnetic flux quantum in the superconducting layer eventually collides with the superconducting&ndash;insulating interfaces on both sides because its radius becomes larger than the width of the superconducting layer. At this instant, the stationary wave will collapse, and a transition will occur: the magnetic quanta are collapsed and thus the uniform magnetic field distribution is achieved, which corresponds to the transition from the superconducting state to the normal state over critical current. Considering a one-dimensional model of the structure, a critical current density equation is derived that indicates an increase in the critical current density for increased applied magnetic field. Subsequently, the same calculation was conducted after changing the direction of the magnetic field component, and the combination of these two calculations expresses the anisotropic property of the structure. The phenomenon is also predicted for anisotropic critical current density. This phenomenon is an important discovery that helps manufacture high-temperature superconducting tape as well as large high-temperature superconducting coils.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 221-227
Author(s):  
Xianfeng Zhao ◽  
Zhiqi Zhou ◽  
Yuan Liu ◽  
Luquan Yang

Magnetic stiffness is one of the important stability parameters of high temperature superconducting levitation systems. Till to now, great efforts have been made to understand levitation properties including flux penetration, magnetization curves, levitation force, ac susceptibilities, etc. In this paper we present a quadratic approximation method for the limit of magnetic stiffness in a high temperature superconducting levitation system based on Kim’s critical state model and Ampère law. The system is composed with a cylindrical permanent magnet (PM) and a coaxial high temperature superconductor (HTS). It is found that the limit of magnetic stiffness depends upon both the penetration history of shielding currents distribution in HTS and applied magnetic field gradients. Furthermore, the influence of the physical parameters, such as critical current density in HTS and applied magnetic field, on the limits of magnetic stiffness is investigated in detail. The obtained results display that magnetic stiffness decreases with the increasing of critical current density, since shielding currents have not penetrated into the large portion of the HTS. With the increase of applied magnetic field, the magnetic stiffness obtain a larger magnification factor. It is related to the increase of the shielding current penetration volume and the internal magnetic field in HTS.


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