Improvements in critical current densities of internal tin diffusion process Nb<inf>3</inf>Sn wires by additions of third elements

1985 ◽  
Vol 21 (2) ◽  
pp. 301-304 ◽  
Author(s):  
K. Yoshizaki ◽  
M. Wakata ◽  
S. Miyashita ◽  
F. Fujiwara ◽  
O. Taguchi ◽  
...  
1987 ◽  
Vol 99 ◽  
Author(s):  
K. Tachikawa ◽  
M. Sugimoto ◽  
N. Sadakata ◽  
O. Kohno

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.


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.


2006 ◽  
Vol 89 (13) ◽  
pp. 132510 ◽  
Author(s):  
Xianping Zhang ◽  
Zhaoshun Gao ◽  
Dongliang Wang ◽  
Zhengguang Yu ◽  
Yanwei Ma ◽  
...  

1995 ◽  
Vol 34 (Part 2, No. 2A) ◽  
pp. L167-L170 ◽  
Author(s):  
Akihiro Kikuchi ◽  
Takashi Kinoshita ◽  
Naohiro Nishikawa ◽  
Seiki Komiya ◽  
KyojiTachikawa

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

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Zhigang Li ◽  
Weike Wang ◽  
Li Zhang ◽  
Zhaorong Yang ◽  
Mingliang Tian ◽  
...  

2014 ◽  
Vol 792 ◽  
pp. 21-26 ◽  
Author(s):  
Tatiana Prikhna ◽  
Michael Eisterer ◽  
Wolfgang Gawalek ◽  
Athanasios G. Mamalis ◽  
Artem Kozyrev ◽  
...  

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.


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