Coated conductor

V.A. Maroni, J.L. Reeves and G. Schwab, On-line characterization of YBCO coated conductors using Raman spectroscopy methods, Appl. Spectrosc., 61, 359-366 (2007). 

FIGURE 23.10 Structures of various YBajCujOy wires (coated conductor). 

Direct transport measurements are generally employed on thin films, tapes and coated conductors. They quickly reach their natural limits as the currents go up and/or the cross-section of the conductor increases. They are fast, i.e., can be started immediately after the magnetic field is set, and trace the I-V characteristics, which is of course most valuable if flux creep or thermally assisted flux flow (Kes et al. 1989) prevails, because the electric field is directly determined. On the other hand, must be defined by a criterion e.g., 1 [xV/cm. It will be affected by the presence of stabilising materials, the silver tube or conducting substrates, and thus generally refers to the overall Jc, wfrich can be converted to the critical current density of the superconductor if the shape and the volume fraction of the superconducting material are known. 

Fig. 44. Transport critical current densities in a coated conductor (1.4 pm Y-123 on rolled Ni) compared to results on Y-123 thin films on SrTiOj, Ag-sheathed Bi-2223 tapes and Tl-1223 on YSZ tapes (Norton et al. 1996).

FIGURE 8.1.14 Conductor structures of IBAD processed and RABiT processed YBCO-coated conductors. 

Typical architectures of these coated conductors are sequences of polycrystalline metallic substrate or biaxially-textured metallic substrate-biaxially-textured... 

Table ir.2-26 Present status of Y based coated conductors according to Yamada and Shiohara [2.69] (IBAD lon-beam-assisted deposition, RABiTS Rolling assisted bi-axially textured substrates, PLD Pulsed laser deposition, TFA-MOD Trifluoroacetate-metal organic deposition)... 

Dr. Bernhard Holzapfel is head of the superconducting materials group at the Leibniz Institute for Solid State and Materials Researdi (IFW) Dresden, Gamany. His main area of research is pulsed laser deposition of functional thin films and superconductivity. Currently he works on the develr ment of HTSC high Jc coated conductors using ion beam assisted deposition or highly textured metal substrates. His work is supported by a number of national and European founded research projects. 

Barbara Schiipp-Niewa studied chemistry in GieBen and Dortmund where she received her Ph.D. in 1999. Since 2000 she has been a scientist at the Leibniz-lnstitute for Solid State and Materials Research Dresden with a focus on crystal structure investigations of oxometalates with superconducting or exciting magnetic ground states. Her current research activities include coated conductors. 

Shown in fig. 16 is the magnetic field dependence of the critical current density for the IBAD and RABiTS based YBCO coated samples recently produced at LANL and ORNL, respectively. These coated samples operated in the liquid nitrogen temperature range clearly outperform the metallic superconductors (NbTi, NbjSn) at 4.2 K. Furthermore, even in the worst field direction H c), and for temperatures below 65 K, the short sample YBCO coated conductors operated in a 8-tesla background field have at least an order of magnitude higher Jc than pre-commercial BSCCO-2223 wire with no applied field. 

Izumi T (2007) Metal organic deposition of YBCO films high Ic and long-length results. In Paranthaman MP, Selvamanickam V (eds) Flux pinning and ac loss studies on YBCO coated conductors, 1st edn. Nova Publishers, Hauppauge, NY, pp 153-169... 

Whitening. The coated conductor passes through water at about 80 °C and thus the HDPE crystallizes, precipitates out, and whitens the solution. 

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