Wires and tapes based on the High Temperature Superconductor (HTSC) YBa2Cu3Ox have the potential to improve power electric systems dramatically in respect to low loss design and high power density. The development of these HTSC power applications like motors, transformers or cables require a high current carrying and low cost basic conductor that can be used in magnetic fields. Currently HTSC coated conductors (CC) are under development as a very promising 2nd generation HTSC tape that is able to fulfil all the necessary requirements. The CC approach is based on depositing epitaxially a HTSC film onto a highly biaxially textured buffered metal tape. A very sharp biaxial texture is required since already low-angle grain boundaries reduce significantly the overall critical current density. Very good textures, and therefore also nearly single crystalline Jc-values exceeding 106 A/cm at 77 K and in zero field, can be obtained either on biaxially textured buffer layers obtained by ion beam assisted film deposition or on Ni-5at%W metal tapes with a sharp cube texture due to recrystallization after heavy cold rolling [1,2]. During the last years, Jc was mainly improved by sharpening the substrate texture. Our recent investigations, however, demonstrated that for such low-angle grain boundary networks the critical current in magnetic fields is limited by the intrinsic grain properties of the HTSC films and not any more by the low-angle grain boundaries . Since the main application sector of these tapes will be connected with magnetic fields, further improvements of the intrinsic HTSC pinning properties in films used for CCs are required. This can be achieved by controlled introduction of nano-scaled artificial defects into the single crystalline Y123 film matrix.
The economic success of Coated Conductors and the production of large amounts of Coated Conductors necessary for power application devices is only possible if high quality but low cost techniques are used to prepare the biaxially textured substrates as well as the epitaxially grown buffer and superconducting layers. Together with industry we target these challenges both in the field of textured substrates and epitaxial film deposition. During the last years especially advanced solution based non vacuum film deposition techniques were successfully applied to the epitaxial growth of complex oxide heterostructures and are now in the process of upscaling.
- J. Eickemeyer, R. Hühne, A. Güth, C. Rodig, U. Gaitzsch, J. Freudenberger, L. Schultz, B. Holzapfel
Textured Ni-9.0 at. % W substrate tapes for YBCO-coated conductors
Supercond. Sci. Technol. 23 (2010) 085012
- R. Hühne, J. Eickemeyer, V.S. Sarma, A. Güth, T. Thersleff, J. Freudenberger, O. de Haas, M. Weigand, J.H. Durrell, L. Schultz, B. Holzapfel
Application of textured highly alloyed Ni-W tapes for coated conductor architectures
Supercond. Sci. Technol. 23 (2010) 034015
- Eickemeyer, J., Hühne, R., Güth, A., Rodig, C., Klauß, H., Holzapfel, B.
Textured Ni-7.5at%W substrate tapes for YBCO coated conductors
Supercond. Sci. Technol. 21 (2008) 105012
- Hühne, R., Subramanya Sarma, V., Okai, D., Thersleff, T., Schultz, L., Holzapfel, B.
Preparation of coated conductor architectures on Ni composite tapes
Supercond. Sci. Technol. 20 (2007) 709