Bismuth-based high T$ sb{c}$ superconductors were prepared from amorphous precursors made by melt-extraction. As-made amorphous fibers ranged from 0.7 $ mu$m to 100 $ mu$m in diameter and 0.2 cm to 5 cm in length. Fibers as thin as 1 $ mu$m in diameter were crystallized to form continuous filaments composed of single-grain chains. / Superconducting transitions at 105 K and 82 K were measured by SQuID magnetometry performed on annealed fibers of initial composition Bi$ sb{1.8}$Pb$ sb{0.2}$Sr$ sb2$Ca$ sb3$Cu$ sb4$O$ sb{x}$. X-ray diffractometry performed on annealed fibers revealed Bi-2212 (T$ sb{c}$ = 85 K) as the majority superconducting phase and Bi-2223 (T$ sb{c}$ = 110K) as the secondary phase. The volume fractions of superconducting phases were estimated to have lower bounds of 30% for 2212 and 5% for 2223. Differential scanning calorimetry measurements made on as-made amorphous fibers indicate a glass transition at T$ sb{g} / simeq$ 685 K, followed by a series of exothermic peaks associated with the formation of precursor crystalline phases identified as the low T$ sb{c}$ 2201 phase and a BCC Bi-Sr-Ca-Cu-O solid-solution with lattice parameter 4.25 A. Further work is required to determine the suitability of these new materials for applications such as multifilamentary conductors.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.60517 |
| Date | January 1991 |
| Creators | Chang, Jack J. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001257137, proquestno: AAIMM72083, Theses scanned by UMI/ProQuest. |
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