High $J_{c}$'s in just-rolled $Tl_{0.8}$$Pb_{0.2}$$Bi_{0.2}$$Sr_{1.8}$$Ba_{0.2}$$Ca_{2.2}$$Cu_{3}$$O_{x}$/Ag tapes

압영제조된 $Tl_{0.8}$$Pb_{0.2}$$Bi_{0.2}$$Sr_{1.8}$$Ba_{0.2}$$Ca_{2.2}$$Cu_{3}$$O_{x}$/Ag 선재에서의 높은 $J_{c}$

  • 정대영 (한국전기연구소 초전도응용연구사업팀) ;
  • 김희권 (한국전기연구소 초전도응용연구사업팀) ;
  • 이해연 (한국전기연구소 초전도응용연구사업팀) ;
  • 허홍수 (한국전기연구소 초전도응용연구사업팀) ;
  • 오상수 (한국전기연구소 초전도응용연구사업팀) ;
  • 이준호 (부산대학교 물리학과) ;
  • 김봉준 (부산대학교 물리학과) ;
  • 김영철 (부산대학교 물리학과)
  • Published : 1999.02.01

Abstract

The grain morphology, the changes in morphology and Jc with the thermo-mechanical treatment (TMT) history, the field dependence of Jc and the nature of intergranular bonding were studied in $T_{10.8}$$Pb_{.2}$$Bi_{0.2}$$Sr_{1.8}$$Ba_{0.2}$$Ca_{2.2}$$Cu_{3}$$O_{z}$/Ag tapes. As a result, incorporation of intermediate rolling during the final heat-treatment resulted in of plate-like TI-1223 grains, and thus enhanced Jc. Jc's near 2.5$\times$104 A/cm2 at 77 K and 0 T were obtained in just rolled tapes with an excellent reproducibility. The high Jc's seem to grain-connectivity easy recovery of excellent grain-connectivity during final heat-treatment after inter -mediate rolling, probably due to retarded T1 evaporation and excessive Ca content in the present composition. The strong field dependence of Jc even in low fields, however, indicated that there still existed significant weak-links and the degree of directional grain-alignment was far from the desired one. The intergranular binding in the tapes seemed to be mainly dominated by SIS junctions.

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