Partial Melt Processing of Solid-Solution Bi2Sr2CaCu2O8+delta Thick-Film Conductors with Nanophase Al2O3 Additions
Journal article (postprint)
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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Partial-melt processing of BiSrCaCuO thick-film conductors with additions of nanophase Al2O3 was studied to increase flux pinning and inhibit SrCaCuO phase defect formation. Nanophase Al2O3 was added to BiSrCaCuO powders with four different compositions three with BiCu approximately 22 and one closer to the ideal Bi-2223 composition. The effect of Al2O3 addition on film microstructural and superconducting properties was studied for a range of partial-melt temperatures. Results were compared to Al2O3-free films with compositions lying within the single-phase solid-solution 2212 region. Nanophase Al2O3 reacted with 2212-type precursors to form a composite of micron size or smaller particles of solid-solution Sr,Ca3Al2O6 in a solid-solution 2212 superconducting matrix. The Ca content of the Sr,Ca3Al2O6 in a solid-solution 2212 superconducting matrix. The Ca content of the Sr,Ca3Al2O6 particles formed was approximately like 2212 precursor. Addition of 6-25 volume fraction of Sr,Ca3Al2O6 to Bi-2212 only slightly reduced Tcs and c-axis texturing, but improved film quality by reducing Sr-Ca-Cu-O defect volume fraction by factors of 2 to 6 and significantly increased Jc by over one order of magnitude for 0 to 2 T applied fields at 20 to 30 K.
- Physical Chemistry
- Electricity and Magnetism