Electrical and Superconducting Properties in Lap Joints for YBCO Tapes

• Published in: Journal of superconductivity and novel magnetism 2013-05, Vol.26 (5), p.2089-2092
• Main Authors: Baldan, C. A., Oliveira, U. R., Bernardes, A. A., Oliveira, V. P., Shigue, C. Y., Ruppert, E.
• Format: Article
• Language: English
• Subjects: Alloys; Characterization and Evaluation of Materials; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductors; Cuprates superconductors (high tc and insulating parent compounds); Deformation and plasticity (including yield, ductility, and superplasticity); Direct current; Electric fields; Exact sciences and technology; Lap joints; Magnetic Materials; Magnetism; Mechanical and acoustical properties; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Original Paper; Physical properties of thin films, nonelectronic; Physics; Physics and Astronomy; Strongly Correlated Systems; Superconducting tapes; Superconductivity; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Tensile stress; Y-based cuprates
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-012-1905-6

The joint process between tapes of coated conductors is a critical issue for most applications of high temperature superconductors (HTSs). In this work several lap joints using different techniques were prepared for three different types of commercially available YBCO-coated conductor tapes, with and without copper stabilizer or stainless steel reinforcement layers. Lap joints with effective lengths in the range of 3 to 20 cm were prepared using low melting point In–Sn and Sn–Pb alloys as soldering materials. The electrical resistance, the critical current, and the n -index of the joints were calculated from the electric field vs . current ( E × I ) characteristic curves under DC current tests and by further subjecting the same samples to tensile stresses. The results showed that the reinforced tape is the more robust tape for the joint-making process, whereas the copper-stabilized tape presented the lowest joint resistivity but with a relatively smaller mechanical strength against tensile stress.