Improved Critical Current Density in $\hbox{\it Ex Situ}$ Processed Carbon-Substituted $\hbox{MgB}_{2}$ Tapes by Mg-Addition

2013 ◽  
Vol 23 (3) ◽  
pp. 6200405-6200405
Author(s):  
H. Fujii ◽  
S. Itoh ◽  
K. Ozawa ◽  
H. Kitaguchi
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ex Situ ◽  
Mg Addition

scholarly journals Effect of grain refinement on enhancing critical current density and upper critical field in undoped MgB2 ex situ tapes

2008 ◽  
Vol 104 (10) ◽  
pp. 103908 ◽  
Author(s):  
A. Malagoli ◽  
V. Braccini ◽  
M. Tropeano ◽  
M. Vignolo ◽  
C. Bernini ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Grain Refinement ◽  
Critical Field ◽  
Current Density ◽  
Upper Critical Field ◽  
Ex Situ

scholarly journals Excess Mg addition MgB2/Fe wires with enhanced critical current density

2008 ◽  
Vol 103 (8) ◽  
pp. 083911 ◽  
Author(s):  
R. Zeng ◽  
L. Lu ◽  
W. X. Li ◽  
J. L. Wang ◽  
D. Q. Shi ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Mg Addition ◽  
Excess Mg

Enhanced critical current density in undoped MgB2 prepared by in situ/ex situ combination technique

2015 ◽  
Vol 218 ◽  
pp. 31-34 ◽  
Author(s):  
M. Shahabuddin Shah ◽  
M. Shahabuddin ◽  
Jafar M. Parakkandy ◽  
Salem Qaid ◽  
Nasser S. Alzayed
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Ex Situ ◽  
Combination Technique

Improved critical current densities in MgB2 tapes fabricated through an ex situ process using powders treated in various chemical solutions

2008 ◽  
Vol 23 (2) ◽  
pp. 507-514 ◽  
Author(s):  
H. Fujii ◽  
K. Togano ◽  
K. Ozawa
Keyword(s):  
Critical Current Density ◽  
Benzoic Acid ◽  
Critical Current ◽  
Current Density ◽  
Chemical Treatment ◽  
Benzene Solution ◽  
Ex Situ ◽  
Chemical Solutions ◽  
Current Densities ◽  
Powder In Tube

We have studied grain coupling and critical current density (Jc) in ex situ processed Fe-sheathed MgB2 tapes fabricated by a powder-in-tube (PIT) technique, using MgB2 powder soaked in various chemical solutions. The grain coupling and the Jc are strongly influenced by the chemical solutions. Compared with the chemical treatment in a benzene solution of benzoic acid, the use of a cyclohexane solution of benzoic acid doubles the Jc value. Cyclohexane is less stable and hence effectively removed from the surface of MgB2 grains, bringing about the improved coupling of grains and the Jc enhancement.

Evidence for Extensive Grain Boundary Meander and Overgrowth of Substrate Grain Boundaries in High Critical Current Density ex Situ YBa2Cu3O7−x Coated Conductors

2005 ◽  
Vol 20 (8) ◽  
pp. 2012-2020 ◽  
Author(s):  
D.M. Feldmann ◽  
D.C. Larbalestier ◽  
T. Holesinger ◽  
R. Feenstra ◽  
A.A. Gapud ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Film Thickness ◽  
Critical Current ◽  
Current Density ◽  
Thick Films ◽  
Coated Conductors ◽  
Ex Situ ◽  
High Critical Current Density ◽  
Ybco Films

It has been generally accepted that YBa2Cu3O7−x (YBCO) films deposited on deformation textured polycrystalline metal tapes result in YBCO grain boundary (GB) networks that essentially replicate the GBs of the underlying substrate. Here we report that for thicker YBCO films produced by a BaF2 ex situ process, this is not true. Using electron backscatter diffraction combined with ion milling, we have been able to map the evolution of the YBCO grain structure and compare it to the underlying template in several coated conductors. For thin (≤0.5 μm) YBCO films deposited on rolling-assisted biaxially textured substrates (RABiTS), the YBCO GBs nearly directly overlap the substrate GBs. For 0.7–1.4 μm YBCO films, the GBs were found to meander along the substrate GBs and along the sample normal, with displacements several times the film thickness. In very thick films (2.5–2.9 μm), the YBCO grains can completely overgrow substrate grains and GBs, resulting in a substantial disconnection of the YBCO and substrate GB networks. Similar behavior is found for BaF2 ex situ YBCO films on ion-beam-assisted deposition-type templates. The ability of the YBCO to overgrow substrate grains and GBs is believed to be due to liquid-phase mediated laminar grain growth. Although the behavior of the YBCO GB networks changes with YBCO film thickness, the samples maintained high critical current density (Jc) values of >2 MA/cm2 for films up to 1.4 μm thick, and up to0.9 MA/cm2 for 2.5–2.9-μm-thick films.

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