Magnetic-field angle dependent critical current densities and flux pinning in commercial YBCO tapes at liquid nitrogen temperatures

Cryogenics ◽  
2010 ◽  
Vol 50 (8) ◽  
pp. 459-464 ◽  
Author(s):  
Yoonseok Lee ◽  
Hirofumi Yamasaki ◽  
Mitsuho Furuse
Keyword(s):  
Magnetic Field ◽  
Critical Current ◽  
Liquid Nitrogen ◽  
Flux Pinning ◽  
Current Densities ◽  
Ybco Tapes

Critical Current Characteristics and Flux Pinning in Fe-Based Pnictide Superconductor

2013 ◽  
Vol 750 ◽  
pp. 288-292
Author(s):  
Bao Rong Ni ◽  
Edmund S. Otabe ◽  
Masaru Kiuchi ◽  
Yan Wei Ma
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Ac Susceptibility ◽  
Pinning Mechanism ◽  
Temperature Dependences ◽  
Current Densities ◽  
Current Characteristics

The superconducting Ba1-xKxFe2As2(x = 0.4) single crystals were prepared by the so-called FeAs self-flux method. The critical temperature by ac susceptibility measurement was estimated to be about 36 K. The magnetic field and temperature dependences of critical current densities were investigated by an ac inductive measurement (Campbell’s method). Unlike the phenomenon of co-existence of the global and local critical current densities observed in many polycrystalline Fe-based superconducting pnictides, it was found that only a uniform critical current density (Jc) flows through the whole sample. The value of Jcat 20 K and 1 T was about 5×108A/m2, which is much smaller than the local critical current density observed in polycrystalline samples. This result implies that a dissimilarity of flux pinning mechanism exists between these two kinds of materials. The force-displacement characteristic of fluxoids in sample was investigated. The Labusch parameter was found to increase monotonously with increasing magnetic field, while the interaction distance was proportional to the fluxoid spacing. These results are consistent with the prediction based on a simple flux pinning mechanism.

Critical Current Densities in Bi2Sr2Cacu2O8+D

1989 ◽  
Vol 169 ◽  
Author(s):  
Shunji Nomura ◽  
Yutaka Yamada ◽  
Tomohisa Yamashita ◽  
Eriko Yoneda ◽  
Hisashi Yoshino ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
Pinning Force ◽  
Critical Fields ◽  
Current Densities ◽  
Upper Critical Fields ◽  
The Magnetic Field

AbstractCritical current densities and upper critical fields were measured for a single crystal of the high Tc oxide superconductor, Bi2Sr2CaCu2O8+d, within the ab basal plane and along the c axis. The anisotropy in critical current densities was observed to be Jc⊥/Jc//=10 in agreement with the anisotropy in resistivity for the normal state. The magnetic field dependence of the critical current densities can be interpreted by the anisotropy in the upper critical fields. The scaling of the critical current density with the magnetic field was found. The critical current density scaled to zero at fields Bc2 in the ab plane and along the c axis which were in good agreement with the upper critical fields measured by transport.The anisotropy in flux pinning force density along the b axis, Fp//b, and along the a axis, Fp//a, was found to be Fp//b/Fp//a=3. The data provided strong evidence for flux pinning by the modulated structure in this system.

Extraction of anisotropic critical current densities and flux pinning potentials

Cryogenics ◽  
1994 ◽  
Vol 34 (4) ◽  
pp. 329-334
Author(s):  
H.L Ji ◽  
Z.X Shi ◽  
Z.Y Zeng ◽  
X Jin ◽  
H.C Fan ◽  
...  
Keyword(s):  
Critical Current ◽  
Flux Pinning ◽  
Current Densities

Preparation of Y-BA-CU Oxide Superconducting Composite Tapes by a Diffusion Process

1987 ◽  
Vol 99 ◽  
Author(s):  
K. Tachikawa ◽  
M. Sugimoto ◽  
N. Sadakata ◽  
O. Kohno
Keyword(s):  
Diffusion Process ◽  
Critical Current ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Oxide Compound ◽  
High Tc ◽  
Powder Metallurgical Process ◽  
Current Densities ◽  
Wire Fabrication ◽  
Made In

Since discovery of the Y-Ba-Cu oxide compound showing superconductivity above liquid nitrogen temperature, intensive study has been under way to clarify nature of the high Tc oxides[l-4]. Much efforts were also made in the field of superconductor applications. A number of studies have been carried out by a powder metallurgical process of Y-Ba-Cu oxide compound wires, although, obtained critical current densities were still low at liquid nitrogen temperature[5–6]. Other techniques for wire fabrication is also being attempted[7–9]. In this study, Y-Ba-Cu oxide superconducting composite tapes were prepared by a diffusion process, which is one of the promising methods to obtain a high critical current density.

Transport Measurements on Superconducting YBa2Cu3O7-δ Thin Film Lines

1989 ◽  
Vol 169 ◽  
Author(s):  
B. H. Moeckly ◽  
D. K. Lathrop ◽  
G. F. Redinbo ◽  
S. E. Russek ◽  
R. A. Buhrman
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Critical Current ◽  
Weak Link ◽  
High Sensitivity ◽  
Weak Links ◽  
Microwave Response ◽  
Field Response ◽  
Current Densities ◽  
Iv Curves

AbstractCritical current densities, magnetic field response, and microwave response have been measured for laser ablated YBa2Cu3O7-δ thin film lines on MgO and SrTiO3 substrates. Films on SrTiO3 have critical current densities > 1 x 106 A/cm2 at 77K and show uniform transport properties in lines of all sizes. Films on MgO have critical current densities which range between 102 and 106 A/cm2 at 77K and show considerable variation from device to device on the same chip. Narrow lines on MgO with low critical current densities show Josephson weak link structure which includes RSJ-like IV curves, microwave induced constant voltage steps, and a high sensitivity to magnetic field. The presence of the Josephson weak links is correlated with small amounts of misaligned grains in films on MgO.

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