The Transport Critical Current Density and Flux Pinning in Superconducting Oxides with Nonsuperconducting Particles / Kritische Transportstromdichte und Flußschläuche-Pinning in supraleitenden Oxiden mit nichtsupraleitenden Teilchen

A comparative study on the effect of PbO (10-30 nm) and HfO2 (60-80 nm) additions on the superconducting properties of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 ((Bi,Pb)-2223) superconductor in the bulk form was carried out. The structure and the microstructure of prepared samples were examined by powder XRD and SEM, respectively. The transition temperature Tc and critical current density Jc was determined by standard dc four-probe method. SEM micrographs showed a homogeneous distribution of Pb and Hf in the samples. It was observed that PbO and HfO2 additions enhanced Jc for all added samples. Jc was the highest for x= 0.05 wt. % of PbO (1130 mA/cm2 at 77 K and 1930 mA/cm2 at 30 K) and HfO2 (900 mA/cm2 at 77 K and 1760 mA/cm2 at 30 K) addition. This study showed that the addition of PbO and HfO2 nanopowder provided extra flux pinning centers in the (Bi, Pb)-2223. PbO with smaller particle size showed higher Jc compared with HfO2 which has a larger particle size.

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Effect of Nanosized NiF2Addition on the Transport Critical Current Density of Ag-Sheathed (Bi1.6Pb0.4)Sr2Ca2Cu3O10Superconductor Tapes

Advances in Materials Science and Engineering ◽

10.1155/2015/146476 ◽

2015 ◽

Vol 2015 ◽

pp. 1-5

Author(s):

M. Hafiz ◽

R. Abd-Shukor

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Flux Pinning ◽

Flux Line ◽

Transport Critical Current Density ◽

Pinning Centers ◽

Sintering Time ◽

Line Network ◽

Powder In Tube

We report the effect of NiF2(10 nm) additions on the transport critical current density,Jcof (Bi1.6Pb0.4)Sr2Ca2Cu3O10/Ag sheathed superconductor tapes. Pellets of (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)x(x=0–0.05 wt.%) superconductor were prepared using the acetate coprecipitation method. The sample with 0.04 wt.% addition of NiF2exhibited the highestJc. Ag-sheathed (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)0.04superconductor tapes were fabricated using the powder-in-tube (PIT) method and sintered at 845°C for 50 and 100 h.Jcof nonadded tapes at 30 K sintered for 50 and 100 h was 6370 and 8280 A/cm2, respectively.Jcof (Bi1.6Pb0.4)Sr2Ca2Cu3O10(NiF2)0.04/Ag tape at 30 K sintered for 50 and 100 h was 14390 and 17270 A/cm2, respectively. In magnetic fields (0 to 0.7 T),Jcof the NiF2added tapes was also higher compared with the nonadded tape indicating that NiF2nanoparticles can act as effective flux pinning centers and longer sintering time improved the microstructure. A steeper increase inJcwas observed below 60 K in the NiF2added tapes which coincided with the Neel temperature,TNof nanosized NiF2(60 K). The pronounced enhancement ofJcwas attributed to the strong interaction between flux line network and the antiferromagnetic NiF2belowTN.

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Effect of Various C Sources Co-Doping on Transport Critical Current Density and Grains-Connectivity of MgB2/Fe Tapes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.214 ◽

2013 ◽

Vol 745-746 ◽

pp. 214-218

Author(s):

Xi Feng Pan ◽

Guo Yan ◽

Xiang Hong Liu ◽

Yong Feng ◽

Ping Xiang Zhang ◽

...

Keyword(s):

Critical Current Density ◽

Critical Current ◽

Current Density ◽

Malic Acid ◽

Flux Pinning ◽

Transport Critical Current Density ◽

Co Doping ◽

The Poor ◽

Powder In Tube

In this paper, we have prepared a series of Fe sheathed MgB2 tapes with SiC, Malic acid and C9H11NO mono-and co-doping by in-situ powder-in-tube (PIT) method, and studied the effects of various C sources co-doping on transport critical current density and flux pinning of MgB2/Fe tapes. The results suggest by various C sources co-doping, the amount of C substitution for boron largely increase, comparing to SiC, Malic acid or C9H11NO mono-doped sample. For MgB2/Fe tapes with 5 mol% SiC+10 wt% Malic acid and 4 wt% C9H11NO+10 wt% Malic acid co-doping, the transport Jc at 4.2 K and 10 T are 14.8 and 13.5 kA/cm2, respectively, which are clearly higher than the Jc of these dopants mono-doped samples. Furthermore, it is found that at the 4 wt.% C9H11NO doped MgB2, the poor in-field Jc should be attributing to the cracks at grains boundary, which results in the bad grains-connectivity.

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