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

点击翻译按钮获取中文摘要

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. ***