Critical Currents&amp;lt;tex&amp;gt;$rm I_rm c(77 rm K)≫350 rm A/cm$&amp;lt;/tex&amp;gt;-Width Achieved in Ex Situ YBCO Coated Conductors Using a Faster Conversion Process

Feenstra, R.; Gapud, A.A.; List, F.A.; Specht, E. D.; Christen, D. K.; Holesinger, T. G.; Feldmann, D. M.

doi:10.1109/tasc.2005.848217

Cited by 38 publications

(39 citation statements)

References 12 publications

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“…Indeed, several groups have reported improved J c values with Y or rare-earth enriched compositions. [72,84,94,95] As will be shown below, phase segregation is substantially reduced and there is a reduction in the number of Ba-Cu-O phases with rare-earth additions.…”

Section: Topmentioning

confidence: 99%

Progress in Nanoengineered Microstructures for Tunable High‐Current, High‐Temperature Superconducting Wires

et al. 2008

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High critical current densities (Jc) in thick films of the Y1Ba2Cu3O7–δ (YBCO, Tc ≈ 92 K) superconductor directly depend upon the types of nanoscale defects and their densities within the films. A major challenge for developing a viable wire technology is to introduce nanoscale defect structures into the YBCO grains of the thick film suitable for flux pinning and the tailoring of the superconducting properties to specific, application‐dependent, temperature and magnetic field conditions. Concurrently, the YBCO film needs to be integrated into a macroscopically defect‐free conductor in which the grain‐to‐grain connectivity maintains levels of inter‐grain Jc that are comparable to the intra‐grain Jc. That is, high critical current (Ic) YBCO coated conductors must contain engineered inhomogeneities on the nanoscale, while being homogeneous on the macroscale. An analysis is presented of the advances in high‐performance YBCO coated‐conductors using chemical solution deposition (CSD) based on metal trifluoroacetates and the subsequent processing to nano‐engineer the microstructure for tuneable superconducting wires. Multi‐scale structural, chemical, and electrical investigations of the CSD film processes, thick film development, key microstructural features, and wire properties are presented. Prospects for further development of much higher Ic wires for large‐scale, commercial application are discussed within the context of these recent advances.

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Section: Topmentioning

confidence: 99%

Progress in Nanoengineered Microstructures for Tunable High‐Current, High‐Temperature Superconducting Wires

et al. 2008

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“…The "fast" process described in Ref. 23 was used for all samples in this study, featuring a conversion temperature of 780°C and water partial pressure of ϳ0.015 atm. The annealing duration was increased in proportion to the film thickness, based on an average growth rate of 0.7 nm/ s. The final YBCO thickness was inferred from the total of the QCM readings, using a previously determined calibration.…”

Section: Experimental Aspectsmentioning

confidence: 99%

“…A detailed description of the fabrication process is presented elsewhere. 23 In order to see detailed microscopic features of the films, transmission electron microscopy ͑TEM͒ studies were performed on representative samples. The TEM images were taken looking from above, along the axis of film deposition ͑plan-view images͒.…”

Section: Experimental Aspectsmentioning

confidence: 99%

Critical currents ofex situYBa2Cu3O7−δthin films on rolling assisted biaxiall

et al. 2006

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The critical current density J c flowing in thin YBa 2 Cu 3 O 7−␦ ͑YBCO͒ films of various thicknesses d has been studied magnetometrically, both as a function of applied field H and temperature T, with a central objective to determine the dominant source of vortex pinning in these materials. The films, grown by a BaF 2 ex situ process and deposited on buffered rolling assisted biaxially textured substrates ͑"RABiTS"͒ substrates of Ni-5 % W, have thicknesses d ranging from 28 nm to 1.5 m. Isothermal magnetization loops M͑H ; T͒ and remanent magnetization M rem ͑T͒ in H = 0 were measured with H ʈ c-axis ͑i.e., normal to film plane͒. The resulting J c ͑d͒ values ͑obtained from a modified critical state model͒ increase with thickness d, peak near d ϳ 120 nm, and thereafter decrease as the films get thicker. For a wide range of temperatures and intermediate fields, we find J c ϰ H −␣ with ␣ ϳ͑0.56-0.69͒ for all materials. This feature can be attributed to pinning by large random defects, which theoretically has power-law exponent ␣ =5/8. Calculated values for the size and density of defects are comparable with those observed by TEM in the films. As a function of temperature, we find J c ͑T , sf͒ϳ͓1−͑T / T c ͒ 2 ͔ n with n ϳ 1.2-1.4. This points to "␦T c pinning" ͑pinning that suppresses T c locally͒ in these YBCO materials.

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“…The YBCO films were grown by BaF 2 precursor deposited by physical vapor deposition. 7,8 Two films were deposited on IBAD tapes ͓CeO 2 ͑200 Å͒ / YSZ ͑ϳ1 m͒/hastelloy͔ and two on the RABiTS architecture CeO 2 ͑150 Å͒/YSZ͑1500 Å͒/Y 2 O 3 ͑200 Å͒/Ni͑1.5 µm͒/NiW ͑3 at .%͒. For IBAD-1 and RABiTS-1, the YBCO GBs closely replicated the substrate boundaries, whereas IBAD-2 and RABiTS-2 are examples of noncorrelating GB networks.…”

Section: Grain and Grain-boundary Critical Currents In Coated Conductmentioning

confidence: 99%

Grain and grain-boundary critical currents in coated conductors with noncorrelating YBa2Cu3O7 and substrate grain-boundary networks

Palau

Puig

Obradors

et al. 2006

Applied Physics Letters

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The superconducting grain-boundary (GB) network of coated conductors (CCs) is usually assumed to be a replica of the substrate network. In this letter, we analyze IBAD and RABITS CCs, where such replica either do or do not exist. We have analyzed the effect of GB overgrowth on the critical currents by quantifying the average superconducting grain size and determining the intragrain and grain-boundary critical current densities, JcG and JcGB. We have employed a recently developed inductive methodology enabling the simultaneous determination of these three parameters. We show that the percolative JcGB may be reduced by 50% if the GB networks do not correlate, while JcG and the grain pinning properties appear unaffected.

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Critical Currents<tex>$rm I_rm c(77 rm K)≫350 rm A/cm$</tex>-Width Achieved in Ex Situ YBCO Coated Conductors Using a Faster Conversion Process

Cited by 38 publications

References 12 publications

Progress in Nanoengineered Microstructures for Tunable High‐Current, High‐Temperature Superconducting Wires

Progress in Nanoengineered Microstructures for Tunable High‐Current, High‐Temperature Superconducting Wires

Critical currents ofex situYBa2Cu3O7−δthin films on rolling assisted biaxiall

Grain and grain-boundary critical currents in coated conductors with noncorrelating YBa2Cu3O7 and substrate grain-boundary networks

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