Analysis of Electromagnetic Properties of Bulk Superconductors

2021 ◽  
Vol 21 (9) ◽  
pp. 4941-4943
Author(s):  
Sang Heon Lee

In the present study, a YBa2Cu3O7−y bulk superconductor added with 5~10 wt% Ag was fabricated employing Sm123 as a seed to produce a superconductive single crystal. Metallic silver was added to the single crystal of YBa2Cu3O7−y to remove defects such as cracks and pores. Electromagnetic properties of the bulk superconductor at 77 K were analyzed based on relationships of magnetic levitation, trapped magnetic force, and critical current density. The critical current density of the superconductor at 77 K and 0 T was 3.53 × 104 A/cm2. Discontinuous points in the distribution of magnetic field lines were not observed, implying that these two specimens grew well as a single crystal without specific weak links. For the growth of a superconductive nano crystal employing slow cooling at temperature of formation of 123 phase, superconductive nano crystals were aligned in a-b direction, the direction of peak current flow. The peak value of the trapped magnetic force of the YBa2Cu3O7−y superconductor specimen was 3.23 kG. Using the FC method, peak forces of attraction and repulsion were 21.696 N and 70.168 N, respectively.

1992 ◽  
Vol 275 ◽  
Author(s):  
Jui H. Wang ◽  
Zhifeng Ren

ABSTRACTThe critical current density Jc of bulk ceramic superconductors is often several orders of magnitude lower than that of a single crystal or oriented fílm of the same material due to the weak links residing at the boundaries between single crystals within the ceramic sample. Assuming that the rate of electron transport within each single crystal is much faster than the average rate of electron transport between adjacent single crystals, a working hypothesis of Jc enhancement by granular reorientation is formulated which includes the“brickwall”model and melt-texturing as special cases with long-range granular alignment which usually leads to rigid and brittle bulk samples. Simple geometric considerations show that only short-range local granular alignment is necessary for high Jc. For mis reason, it should be possible to make flexible superconducting wires and tapes for commercial applications at or above 77K.


Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.


2011 ◽  
Vol 324 ◽  
pp. 241-244 ◽  
Author(s):  
R. Mawassi ◽  
R. Awad ◽  
Mohamad Roumie ◽  
M. Kork ◽  
I. Hassan

The major limitation of Bi-system superconductor applications is the intergrain weak links and weak flux pinning capability producing low critical current density of the Bibased phases. In order to enhance these characteristics and other superconducting properties, effective flux pinning centers are introduced into high temperature superconductors. In this work, different weight percentages of ZnO nano oxide were introduced at the final stage of the Bi1.8Pb0.4Sr2Ca2Cu3O10-y superconductor preparation process. Phase characterization was completed by X-ray diffraction (XRD). Exact constitution of the samples was determined using particle induced X-ray emission (PIXE). Granular and microstructure were investigated using scanning electron microscopy (SEM). Electrical resistivity as function of the temperature was carried to evaluate the relative performance of samples, and finally, E-J characteristic curves were obtained at 77K. Using 0.4 ZnO weight percentage, the electrical and granular properties were greatly enhanced, indicating more efficient pinning mechanisms. A critical current density of 949 A/cm2 was obtained which represents more than twice the value obtained for the pure sample (Jc= 445 A/cm2).


2015 ◽  
Vol 92 (14) ◽  
Author(s):  
Yue Sun ◽  
Sunseng Pyon ◽  
Tsuyoshi Tamegai ◽  
Ryo Kobayashi ◽  
Tatsuya Watashige ◽  
...  

2010 ◽  
Vol 117 ◽  
pp. 63-68 ◽  
Author(s):  
Krishnankutty Vinod ◽  
Syamaprasad Upendran

The present study focuses on the preparation of good quality MgB2 superconductor in bulk, wire/tape forms and on the improvement of in-field critical current density [JC(H)]. MgB2 bulk superconductor was prepared by a simple Powder-In-Sealed-Tube (PIST) method and MgB2 wires and tapes were prepared by the Powder-In-Tube (PIT) method. A novel electrical self-heating method was introduced for the preparation of Fe sheathed MgB2 wires and tapes. Burned Rice Husk (BRH), an inexpensive natural material is found to be one of the best additives for enhancing the in-field critical current density of MgB2. By selecting suitable combinations of additives a significant enhancement of the critical current density by 1-2 orders of magnitude were achieved for fields > 5 T, at 5-15 K.


2003 ◽  
Vol 82 (25) ◽  
pp. 4519-4521 ◽  
Author(s):  
S. R. Foltyn ◽  
P. N. Arendt ◽  
Q. X. Jia ◽  
H. Wang ◽  
J. L. MacManus-Driscoll ◽  
...  

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542038 ◽  
Author(s):  
Yiyun Lu ◽  
Yujie Qin

Numerical simulations of thermo-electromagnetic properties of a high temperature superconducting (HTS) bulk levitating over a permanent magnetic guideway (PMG) are performed by resorting to the quasistatic approximation of the H-method coupling with the classical description of the heat conduction equation. The numerical resolving codes are practiced with the help of the finite element program generation system (FEPG) platform using finite element method (FEM). The [Formula: see text]–[Formula: see text] power law is used to describe the electric current nonlinear characteristics of HTS bulk. The simulation results show that the heat conduction and the critical current density are tightly relative to the thermal effects of the HTS bulk over the PMG. The heat intensity which responds to the heat loss of the HTS bulk is mainly distributed at the two bottom-corners of the bulk sample.


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