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Practical superconductor development for electrical power applications - annual report for FY 2003.

Description: Most large-scale applications of high-critical-temperature superconductors will require conductors that can carry large currents in the presence of applied magnetic fields. This report describes progress at Argonne National Laboratory (ANL) in the research and development of practical superconducting components and devices. These efforts primarily focus on the use of Y-Ba-Cu-O system in second-generation conductors, but they also include investigations of Bi-Pb-Sr-Ca-Cu-O systems for use in first-generation conductors. Results are presented in the areas of processing first-generation superconductors and second-generation (2G) superconductors with several different architectures, applying Raman microscopy to the characterization of 2G conductors, studying the role of oxygen doping in the grain boundary transport of 2G conductors, and evaluating the mechanical properties of 2G conductors.
Date: October 18, 2004
Creator: Balachandran, U.; Baurceanu, R.; Clauss, H.; Dorris, S. E.; Emerson, J. E.; Erck, R. A et al.
Partner: UNT Libraries Government Documents Department

Texture development of MgO buffer layers grown by inclined substrate deposition.

Description: Biaxially textured magnesium oxide (MgO) films used as template layers for YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO)-coated conductors have been grown efficiently and consistently by inclined substrate deposition (ISD). Further improvement in texture and a decrease in surface roughness were obtained by depositing a homoepitaxial MgO layer on the ISD MgO layer at an elevated temperature and flat angle. The texture of the ISD layer was studied as a function of thickness by X-ray diffraction and scanning and transmission electron microscopy. Surface roughness of the ISD and homoepitaxial layers was investigated by atomic force microscopy. Based on the results, the optimal thickness of the ISD layer was determined.
Date: August 16, 2002
Creator: Koritala, R. E.; Ma, B.; Miller, D. J.; Li, M.; Fisher, B. L. & Balachandran, U.
Partner: UNT Libraries Government Documents Department

Biaxially aligned template films fabricated by inclined-substrate deposition for YBCO-coated conductor applications.

Description: Inclined substrate deposition (ISD) has the potential for rapid production of high-quality biaxially textured buffer layers, which are important for YBCO-coated conductor applications. We have grown biaxially textured MgO films by ISD at deposition rates of 20-100 {angstrom}/sec. Columnar grains with a roof-tile surface structure were observed in the ISD-MgO films. X-ray pole figure analysis revealed that the (002) planes of the ISD-MgO films are tilted at an angle from the substrate normal. A small {phi}-scan full-width at half maximum (FWHM) of {approx}9{sup o} was observed on MgO films deposited at an inclination angle of 55{sup o}. In-plane texture in the ISD MgO films developed in the first 0.5 {micro}m from the interface, then stabilized with further increases in film thickness. YBCO films deposited by pulsed laser deposition on ISD-MgO buffered Hastelloy C276 substrates were biaxially aligned with the c-axis parallel to the substrate normal. T{sub c} of 91 K with a sharp transition and transport J{sub c} of 5.5 x 10{sup 5} A/cm{sup 2} at 77 K in self-field were measured on a YBCO film that was 0.46-{micro}m thick, 4-mm wide, 10-mm long.
Date: August 12, 2002
Creator: Ma, B.; Li, M.; Koritala, R. E.; Fisher, B. L.; Erck, R. A.; Dorris, S. E. et al.
Partner: UNT Libraries Government Documents Department

Fabrication of biaxially textured templates for coated conductors by inclined substrate deposition.

Description: YBCO-coated conductors will enable the development of smaller, lighter, more-efficient electric power devices that can be operated at temperatures approaching that of liquid nitrogen. The critical current density (J{sub c}) of YBCO films on flexible metallic substrates has been significantly improved by epitaxially growing the YBCO on biaxially textured template films. Inclined substrate deposition (ISD) offers the potential for rapidly producing high-quality biaxially textured buffer layers that are suitable for YBCO-coated conductors. Using the ISD method, we have grown biaxially textured MgO films at deposition rates of 20-100 {angstrom}/sec. Electron microscopy of the ISD-MgO films revealed columnar grains topped off by MgO (002) planes, and X-ray pole figure analysis showed that the (002) planes are tilted with respect to the substrate normal, giving ISD-MgO films a roof-tile surface morphology. A small phi-scan full-width at half maximum of {approx}10{sup o} was observed on ISD-MgO films deposited with a substrate inclination of 55{sup o}. YBCO films were grown on ISD-MgO buffered Hastelloy substrates by pulsed laser deposition. A sample that was 0.42 {micro}m x 0.45 mm x 1 cm gave a transport J{sub c} of {approx}0.34 MA/cm{sup 2} at 77 K in self-field. Details of ISD-MgO film fabrication and characterization, as well as the results of YBCO deposited on the ISD-MgO architecture, are presented.
Date: August 21, 2002
Creator: Dorris, S. E.; Ma, B.; Li, M.; Fisher, B. L.; Koritala, R. E.; Erck, R. et al.
Partner: UNT Libraries Government Documents Department

Practical superconductor development for electrical power applications : annual report for FY 2001.

Description: Most large-scale applications of high-critical-temperature superconductors will require wires or tapes that can carry large current in applied magnetic fields. This report describes research and development efforts at Argonne National Laboratory (ANL) aimed at producing practical superconducting components and devices using the Y-Ba-Cu-O and Bi-(Pb)-Sr-Ca-Cu-O systems. Topics discussed include various methods of forming second- and first-generation composite conductors, characterization of their structures and superconducting and mechanical properties, modeling of grain-boundary current transport, and the testing and modeling of a superconducting fault current limiter.
Date: May 2, 2002
Creator: Cha, Y. S.; Dorris, S. E.; Dusek, J. T.; Emerson, J. E.; Erck, R. A.; Fisher, B. L. et al.
Partner: UNT Libraries Government Documents Department

Inclined substrate deposition of magnesium oxide for YBCO-coated conductors.

Description: Thin films of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) were grown on MgO buffered metallic substrates by pulsed laser deposition (PLD). The MgO buffer films, which provide the initial biaxial texture, had been grown on polished Hastelloy C276 (HC) tapes using inclined substrate deposition (ISD). The ISD process is promising for the fabrication of coated superconductor wires because it produces biaxially textured template films on nontextured substrate at high deposition rates. Biaxially aligned MgO films were deposited at deposition rates of 20 to 100 {angstrom}/sec. The buffer films were deposited on these template films before ablation of the YBCO films by PLD. The microstructure was studied by scanning electron microscopy and atomic force microscopy. X-ray pole figure analysis and {phi}- and {omega}-scans were used for texture characterization. Good in- and out-of-plane textures were observed on the ISD MgO films ({approx}1.5 {micro}m thick). The full width at half maximums were 9.2{sup o} for the MgO (002) {phi}-scan and 5.4{sup o} for the {omega}-scan. Cube-on-cube epitaxial growth of yttria-stabilized zirconia (YSZ) and ceria (CeO{sub 2}) films on the ISD MgO films was also achieved by PLD. A superconducting critical temperature of 90 K, with a sharp transition, and transport critical current density of >2.5 x 10{sup 5} A/cm{sup 2} were obtained on a 0.5-{micro}m-thick, 0.5-cm-wide, and 1-cm-long YBCO film with MgO buffer layer at 77 K in self-field.
Date: April 26, 2002
Creator: Ma, B.; Li, M.; Fisher, B. L.; Koritala, R. E.; Dorris, S. E.; Maroni, V. A. et al.
Partner: UNT Libraries Government Documents Department

Practical superconductor development for electrical power applications: annual report for FY 2002.

Description: Most large-scale applications of high-critical-temperature superconductors will require conductors that can carry large currents in the presence of applied magnetic fields. This report describes progress at Argonne National Laboratory (ANL) in the research and development of practical superconducting components and devices using the Y-Ba-Cu-O and Bi-Pb-Sr-Ca-Cu-O systems. Results are presented in the areas of fabrication of second- and first-generation composite conductors, characterization of their structures and superconducting properties, investigation of grain-boundary current transport and factors that influence it, testing and modeling of the components of a superconducting fault current limiter, and the measurement and modeling of a superconductor's response to a transient such as that in a fault current limiter after a fault.
Date: April 9, 2003
Creator: Baurceanu, R.; Cha, Y. S.; Dorris, S. E.; Emerson, J. E.; Erck, R. A.; Fisher, B. L. et al.
Partner: UNT Libraries Government Documents Department

Microstructural development and superconducting properties of BaO{sub 2}-added Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x}.

Description: Investigations on the effects of Ba additions in Bi-2212 superconductors are focused on compositional, microstructural, and magnetization studies. In previous studies, we showed that BaO{sub 2} reacts with Bi-2212 to form second phases. Zero-field and in-field transport properties in Ag-clad BaO{sub 2} added Bi-2212 tapes had been improved at 4.2 K [1]-[3]. SEM micrographs, pole figures, and transport critical currents versus magnetic field orientation suggest that BaO{sub 2} has a strong influence on the microstructural properties. Magnetization studies revealed that BaO{sub 2} does not affect the pinning properties of optimally added Bi-2212. To estimate the potential of BaO{sub 2} additions in creating possible pinning sites, TEM investigations were carried out focusing on sub-micrometer inclusions and growth defects in the superconducting phase.
Date: November 8, 2000
Creator: Koritala, R. E.; Trociewitz, U. P.; Bacaltchuk, C.; Schwartz, J.; Sahm, P. R. & Brandao, L.
Partner: UNT Libraries Government Documents Department

Practical superconductor development for electrical power applications - annual report for FY 2000.

Description: Most large-scale high-critical-temperature superconductor applications require wires or tapes that an carry high currents in applied magnetic fields. This report describes technical progress of research and development efforts aimed at producing superconducting components and devices in the Y-Ba-Cu-O and Bi-(Pb)-Sr-Ca-Cu-O systems. Topics discussed are formation of first- and second-generation composite conductors, characterization of structures and superconducting and mechanical properties, modeling of grain-boundary current transport, and fabrication and analysis of prototype components.
Date: January 25, 2001
Creator: Balachandran, U.; Cha, Y.S.; Dorris, S.E.; Dusek, J.T.; Emerson, J.E.; Fisher, B.L. et al.
Partner: UNT Libraries Government Documents Department