Current Enhancement by Fission-Induced Columnar Defects in High Temperature Superconductors

本项目将研究裂变引起的柱状缺陷对各种高tc材料涡旋钉扎的影响，如实用的掺铅Bi-2223/Ag复合线材或带，汞基铜外延薄膜和块状材料，以及Bi-2212单晶。目标是开发实用的方法来提高临界电流密度，Jc，在这些材料中，通过故意引入扩展缺陷，用GeV范围的光粒子照射，具有扩大到大型预制结构的潜力。该项目结合了田纳西大学诺克斯维尔分校和IBM t.j.沃森研究中心的团队的共同努力，在超导体和各种磁性和传输方法的研究方面展示了专业知识。该项目还利用了洛斯阿拉莫斯国家实验室的专业知识和辐照设施，以及美国超导公司的电线和胶带制造技术。高温超导体的大规模应用还不可能，因为在制造能够承载大电流的电线或磁带方面存在困难，也就是说，在高磁场中具有大的临界电流密度，Jc。这些问题与磁场存在下高tc材料固有的电流“涡流”的耗散运动有关。该项目采用辐射诱导损伤中心或柱状缺陷，其作用是“钉住”涡流，使其无法移动，从而大大增强了材料的载流性能。该项目结合了田纳西大学诺克斯维尔分校和IBM t.j.沃森研究中心的团队的共同努力，在超导体和各种磁性和传输方法的研究方面展示了专业知识。该项目还利用了洛斯阿拉莫斯国家实验室的专业知识和辐照设施，以及美国超导公司的电线和胶带制造技术。* * *

9510731 Thompson This project will investigate the effect of fission-induced columnar defects on vortex pinning in a variety of high-Tc materials, such as practical Pb-doped Bi-2223/Ag composite wire or tapes, Hg-based cuprate epitaxial films and bulk materials, and Bi-2212 single crystals. The goal is to develop practical ways to enhance the critical current density, Jc, in these materials via deliberate introduction of extended defects with GeV range light particle irradiation, with potential for scale-up to large prefabricated structures. The project incorporates a focused joint effort of groups at the University of Tennessee, Knoxville, and at IBM T. J. Watson Research Center, with demonstrated expertise in studies of superconductors and in various magnetic and transport methods. The project also draws on the expertise and irradiation facilities at Los Alamos National Laboratory and on fabrication of wires and tapes at the American Superconductor Corporation. %%% Large-scale applications of high temperature superconductors are not yet possible due to difficulties in manufacturing wires or tapes capable of carrying large currents, that is, having large critical current densities, Jc, sustainable in high magnetic fields. The problems are related to dissipative motion of current "vortices" which are intrinsic to the high-Tc materials in the presence of magnetic fields. This project employs radiation induced damage centers, or columnar defects, which act to "pin" the vortices so they are unable to move, and, as a result, greatly enhance the current carrying properties of the materials. The project incorporates a focused joint effort of groups at the University of Tennessee, Knoxville, and at IBM T. J. Watson Research Center, with demonstrated expertise in studies of superconductors and in various magnetic and transport methods. The project also draws on t he expertise and irradiation facilities at Los Alamos National Laboratory and on fabrication of wires and tapes at the American Superconductor Corporation. ***