Effect of high-energy ball milling time on superconducting properties of MgB 2 with low purity boron powder Article

cited authors

  • Wang, C; Ma, Y; Zhang, X; Wang, D; Gao, Z; Yao, C; Wang, C; Oguro, H; Awaji, S; Watanabe, K

fiu authors

abstract

  • MgB 2 bulks and tapes were fabricated using ball-milled precursor powders. The selected B powders have the -rhombohedral crystalline structure as a main phase, with a small amount of MgO impurity. Milling time was tested from 0.5 to 120h to get an optimized value. It is found that ball milling can facilitate MgB 2 phase formation, refine the MgB 2 grains and increase the defect density. Moreover, the active area, B c2 and flux pinning are improved, which is of benefit to the enhancement of J c performance. The 80 h milled MgB 2 bulk sample has a J c value of 2.8×10 4Acm 2 at 5K and 6T, 41 times larger than that of the 0.5h sample. At the same time, the transport J c of the 80h MgB 2 tape reaches 2.3×10 3Acm 2 at 4.2K and 9T, 32 times larger than that of the 0.5h one. Due to the increase of impurities and the release of lattice deformation and strain, the J c was decreased for the sample milled up to 120h. © 2012 IOP Publishing Ltd.

publication date

  • March 1, 2012

Digital Object Identifier (DOI)

volume

  • 25

issue

  • 3