MgB Advances
Posted: Mon Sep 26, 2011 7:29 am
http://iopscience.iop.org/0953-2048/24/ ... 105005.pdf
Abstract
MgB2 tapes were fabricated by the in situ powder-in-tube method using C2H4O3-treated B powder as a source material. It is found that the Jc values of MgB2 tapes are significantly improved by treating B powder with C2H4O3. At 4.2K, the Jc of the C2H4O3-treated sample sintered at 800 ◦C reaches 5 × 10^3 A cm−2 at 12 T. The C2H4O3-treated B improves not only the upper critical field through enhancing intraband scattering but also the flux pinning by increasing grain boundaries and C substitution effects. A larger amount of intragranular structural defects and grain boundaries were found in the C2H4O3-treated MgB2 matrix. Benefiting from the good crystallinity, the C2H4O3-treated tape sintered at 800 ◦C shows a bigger active area fraction and a higher Jc than the sample sintered at 700 ◦C. These results suggest that treating B powder with C2H4O3 is an effective way to enhance the critical current density of MgB2 superconductors.
ChengduoWang1, YanweiMa1, Xianping Zhang1,
Dongliang Wang1, Zhaoshun Gao1, Chao Yao1, Satoshi Awaji2 and
KazuoWatanabe2
1 Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering,
Chinese Academy of Sciences, PO Box 2703, Beijing 100080, People’s Republic of China
2 High Field Laboratory for SuperconductingMaterials, Institute for Materials Research,
Tohoku University, Sendai 980-8577, Japan
Abstract
MgB2 tapes were fabricated by the in situ powder-in-tube method using C2H4O3-treated B powder as a source material. It is found that the Jc values of MgB2 tapes are significantly improved by treating B powder with C2H4O3. At 4.2K, the Jc of the C2H4O3-treated sample sintered at 800 ◦C reaches 5 × 10^3 A cm−2 at 12 T. The C2H4O3-treated B improves not only the upper critical field through enhancing intraband scattering but also the flux pinning by increasing grain boundaries and C substitution effects. A larger amount of intragranular structural defects and grain boundaries were found in the C2H4O3-treated MgB2 matrix. Benefiting from the good crystallinity, the C2H4O3-treated tape sintered at 800 ◦C shows a bigger active area fraction and a higher Jc than the sample sintered at 700 ◦C. These results suggest that treating B powder with C2H4O3 is an effective way to enhance the critical current density of MgB2 superconductors.
ChengduoWang1, YanweiMa1, Xianping Zhang1,
Dongliang Wang1, Zhaoshun Gao1, Chao Yao1, Satoshi Awaji2 and
KazuoWatanabe2
1 Key Laboratory of Applied Superconductivity, Institute of Electrical Engineering,
Chinese Academy of Sciences, PO Box 2703, Beijing 100080, People’s Republic of China
2 High Field Laboratory for SuperconductingMaterials, Institute for Materials Research,
Tohoku University, Sendai 980-8577, Japan