WorldWideScience

Sample records for film superconductor development

  1. Briefing on superconductor developments

    International Nuclear Information System (INIS)

    Larbalestier, D.

    1987-01-01

    In this paper, the author covers the technology of the new oxide superconductors and how they might relate to the existing superconductors. He discusses old-fashioned superconductors; the material science of superconductors; the new oxide superconductors; and the future of oxide superconductors. 13 figures, 1 table

  2. Percolation effect in thick film superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sali, R.; Harsanyi, G. [Technical Univ. of Budapest (Hungary)

    1994-12-31

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T{sub c} and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm{sup 2}. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  3. Percolation effect in thick film superconductors

    International Nuclear Information System (INIS)

    Sali, R.; Harsanyi, G.

    1994-01-01

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T c and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm 2 . The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed

  4. Practical superconductor development for electrical power applications

    International Nuclear Information System (INIS)

    Goretta, K.C.

    1991-10-01

    Development of useful high-critical-temperature (high-T c ) superconductors requires synthesis of superconducting compounds; fabrication of wires, tapes, and films from these compounds; production of composite structures that incorporate stabilizers or insulators; and design and testing of efficient components. This report describes technical progress of research and development efforts aimed at producing superconducting components based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and Tl-Ba-Ca-Cu oxides systems. Topics discussed are synthesis and heat treatment of high-T c superconductors, formation of monolithic and composite wires and tapes, superconductor/metal connectors, characterization of structures and superconducting and mechanical properties, and fabrication and properties of thin films. Collaborations with industry and academia are also documented. 10 figs

  5. Superconductors

    International Nuclear Information System (INIS)

    1988-01-01

    The chapter 6.3 p. 143 to 153 of this book deals with superconductors 19 items are briefly presented with address of manufacturer or laboratory to contact, mainly in the USA or Japan. In particular magnets, films, high temperature superconductors and various applications are presented [fr

  6. High temperature superconductor thin films

    International Nuclear Information System (INIS)

    Correra, L.

    1992-01-01

    Interdisciplinary research on superconducting oxides is the main focus of the contributors in this volume. Several aspects of the thin film field from fundamental properties to applications are examined. Interesting results for the Bi system are also reviewed. The 132 papers, including 8 invited, report mainly on the 1-2-3 system, indicating that the Y-Ba-Cu-O and related compounds are still the most intensively studied materials in this field. The volume attests to the significant progress that has been made in this field, as well as reporting on the challenging problems that still remain to be solved. The papers are presented in five chapters, subsequently on properties, film growth and processing, substrates and multilayers, structural characterization, and applications

  7. Development of superconductor bulk for superconductor bearing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong (and others)

    2008-08-15

    Current carrying capacity is one of the most important issues in the consideration of superconductor bulk materials for engineering applications. There are numerous applications of Y-Ba-Cu-O (YBCO) bulk superconductors e.g. magnetic levitation train, flywheel energy storage system, levitation transportation, lunar telescope, centrifugal device, magnetic shielding materials, bulk magnets etc. Accordingly, to obtain YBCO materials in the form of large, single crystals without weak-link problem is necessary. A top seeded melt growth (TSMG) process was used to fabricate single crystal YBCO bulk superconductors. The seeded and infiltration growth (IG) technique was also very promising method for the synthesis of large, single-grain YBCO bulk superconductors with good superconducting properties. 5 wt.% Ag doped Y211 green compacts were sintered at 900 .deg. C {approx} 1200 .deg.C and then a single crystal YBCO was fabricated by an infiltration method. A refinement and uniform distribution of the Y211 particles in the Y123 matrix were achieved by sintering the Ag-doped samples. This enhancement of the critical current density was ascribable to a fine dispersion of the Y211 particles, a low porosity and the presence of Ag particles. In addition, we have designed and manufactured large YBCO single domain with levitation force of 10-13 kg/cm{sup 2} using TSMG processing technique.

  8. Development of superconductor application technology

    Energy Technology Data Exchange (ETDEWEB)

    Hong, G W; Kim, C J; Lee, H G; Lee, H J; Kim, K B; Won, D Y; Jang, K I; Kwon, S C; Kim, W J; Ji, Y A; Yang, S W; Kim, W K; Park, S D; Lee, M H; Lee, D M; Park, H W; Yu, J K; Lee, I S; Kim, J J; Choi, H S; Chu, Y; Kim, Y S; Kim, D H

    1997-09-01

    Fabrication of high Tc bulk superconductor and its application, fabrication of superconducting wire for electric power device and analysis for cryogenic system were carried out for developing superconductor application technologies for electric power system. High quality YBaCuO bulk superconductor was fabricated by controlling initial powder preparation process and prototype flywheel energy storage device was designed basically. The superconducting levitation force measuring device was made to examine the property of prepared superconductor specimen. Systematic studies onthe method of starting powder preparation, mechanical fabrication process, heat treatment condition and analysis of plastic deformation were carried out to increase the stability and reproducibility of superconducting wire. A starting power with good reactivity and fine particle size was obtained by mechanical grinding, control of phase assemblage, and emulsion drying method. Ag/BSCCO tape with good cross sectional shape and Jc of 20,000 A/cm{sup 2} was fabricated by applying CIP packing procedure. Multifilamentary wire with Jc of 10,000 A/cm{sup 2} was fabricated by rolling method using square billet as starting shape. The joining of the multifilamentary wire was done by etching and pressing process and showed 50% of joining efficiency. Analysis on the heat loss in cryostat for high Tc superconducting device was carried out for optimum design of the future cryogenic system. (author). 66 refs., 104 figs.

  9. Development of superconductor application technology

    International Nuclear Information System (INIS)

    Hong, G. W.; Kim, C. J.; Lee, H. G.; Lee, H. J.; Kim, K. B.; Won, D. Y.; Jang, K. I.; Kwon, S. C.; Kim, W. J.; Ji, Y. A.; Yang, S. W.; Kim, W. K.; Park, S. D.; Lee, M. H.; Lee, D. M.; Park, H. W.; Yu, J. K.; Lee, I. S.; Kim, J. J.; Choi, H. S.; Chu, Y.; Kim, Y. S.; Kim, D. H.

    1997-09-01

    Fabrication of high Tc bulk superconductor and its application, fabrication of superconducting wire for electric power device and analysis for cryogenic system were carried out for developing superconductor application technologies for electric power system. High quality YBaCuO bulk superconductor was fabricated by controlling initial powder preparation process and prototype flywheel energy storage device was designed basically. The superconducting levitation force measuring device was made to examine the property of prepared superconductor specimen. Systematic studies onthe method of starting powder preparation, mechanical fabrication process, heat treatment condition and analysis of plastic deformation were carried out to increase the stability and reproducibility of superconducting wire. A starting power with good reactivity and fine particle size was obtained by mechanical grinding, control of phase assemblage, and emulsion drying method. Ag/BSCCO tape with good cross sectional shape and Jc of 20,000 A/cm 2 was fabricated by applying CIP packing procedure. Multifilamentary wire with Jc of 10,000 A/cm 2 was fabricated by rolling method using square billet as starting shape. The joining of the multifilamentary wire was done by etching and pressing process and showed 50% of joining efficiency. Analysis on the heat loss in cryostat for high Tc superconducting device was carried out for optimum design of the future cryogenic system. (author). 66 refs., 104 figs

  10. Fluxons in thin-film superconductor-insulator superlattices

    DEFF Research Database (Denmark)

    Sakai, S.; Bodin, P.; Pedersen, Niels Falsig

    1993-01-01

    In a system of thin alternating layers of superconductors and insulators the equations describing static and dynamic fluxon solutions are derived. The approach, represented by a useful compact matrix form, is intended to describe systems fabricated for example of niobium or niobium-nitride thin...... films; in the limit of ultrathin superconductor films it may give a model for describing fluxon motion in layered high-Tc superconductors. Numerical examples of current versus voltage curves to be expected in such an experiment are presented. Journal of Applied Physics is copyrighted by The American...

  11. Microwave impedance of epitaxial high-temperature superconductor films

    International Nuclear Information System (INIS)

    Melkov, G.A.; Malyshev, V.Yu.; Bagada, A.V.

    1995-01-01

    In the 3 cm band dependences of the epitaxial HTS film surface resistance on the magnitude of ac and dc magnetic fields have been measured. YBa 2 Cu 3 O 7-σ films on sapphire were investigated. It was established that alternating magnetic field produces a stronger impact on the surface resistance than dc field. To explain experimental results the assumption is made that a HTS film is not an ideal superconductor and consists of series-connected sections of various types: sections of an ideal superconductor, sections of low and large resistance intragranular Josephson junctions, shunted by the ideal superconductor, and finally, sections of intergranular Josephson junctions few for epitaxial films. In these conditions the dependences of the surface resistance on dc magnetic field are caused by Abrikosov's vortices moving in ideal superconductive sections, and dependences on the amplitude of ac magnetic field are caused by switching of large resistance junctions to a low resistance state

  12. Superconductors

    CERN Document Server

    Narlikar, A V

    2014-01-01

    Superconductors is neither about basic aspects of superconductivity nor about its applications, but its mainstay is superconducting materials. Unusual and unconventional features of a large variety of novel superconductors are presented and their technological potential as practical superconductors assessed. The book begins with an introduction to basic aspects of superconductivity. The presentation is readily accessible to readers from a diverse range of scientific and technical disciplines, such as metallurgy, materials science, materials engineering, electronic and device engineering, and chemistry. The derivation of mathematical formulas and equations has been kept to a minimum and, wherever necessary, short appendices with essential mathematics have been added at the end of the text. The book is not meant to serve as an encyclopaedia, describing each and every superconductor that exists, but focuses on important milestones in their exciting development.

  13. Stability analysis of magnetic flux in thin-film superconductors

    International Nuclear Information System (INIS)

    Denisov, Dmitry

    2007-01-01

    This work presents theoretical results in the physics of superconductivity. The first part of the work is dedicated to the problem of thermomagnetic instabilities and flux avalanches in thin film superconductors. The second part describes the problem of flux trapped in the hole of the superconducting ring (author)

  14. Development of YBCO Superconductor for Electric Systems: Cooperative Research and Development Final Report, CRADA Number CRD-04-150

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, R.

    2013-03-01

    The proposed project will be collaborative in exploration of high temperature superconductor oxide films between SuperPower, Inc. and the National Renewable Energy Laboratory. This CRADA will attempt to develop YBCO based high temperature oxide technology.

  15. Electromagnetic properties of thin film lead superconductors

    International Nuclear Information System (INIS)

    Moriyama, K.

    1978-01-01

    The dependence of critical film magnetic field H/sub cf/ on temperature, thickness, and surface texture of lead superconducting films was investigated, as well as the relationship between the applied magnetic field and the applied current at the critical field. Temperature and thickness dependence data were consistent with the predictions of London, of Ginzburg, and of Bardeen, Cooper, and Schreiffer. The values of H/sub cf/ of lead films deposited on a rough surface were consistently lower than for those on a smooth surface and so were not in agreement with any currently accepted theory. The degree of lowering of H/sub cf/ by a rough surface was greater in thin films than in thick films. The expected dependence of penetration depth lambda on thickness d was not observed, and the range of lambda was somewhat greater than expected. The range of coherence length was greater than predicted. The prediction for temperature dependence of critical current by Glover and Coffey was found to involve some oversimplification, and a suggested correction is supported by the data. For applied magnetic fields perpendicular to the applied current and parallel to the film surface, the relationship between the critical values of the magnetic field and the current was as predicted for lead films by Alphonse and Bergstein

  16. Epitaxial thin film growth and properties of unconventional oxide superconductors. Cuprates and cobaltates

    International Nuclear Information System (INIS)

    Krockenberger, Y.

    2006-01-01

    The discovery of high-temperature superconductors has strongly driven the development of suited thin film fabrication methods of complex oxides. One way is the adaptation of molecular beam epitaxy (MBE) for the growth of oxide materials. Another approach is the use of pulsed laser deposition (PLD) which has the advantage of good stoichiometry transfer from target to the substrate. Both techniques are used within this thesis. Epitaxial thin films of new materials are of course needed for future applications. In addition, the controlled synthesis of thin film matter which can be formed far away from thermal equilibrium allows for the investigation of fundamental physical materials properties. (orig.)

  17. Epitaxial thin film growth and properties of unconventional oxide superconductors. Cuprates and cobaltates

    Energy Technology Data Exchange (ETDEWEB)

    Krockenberger, Y.

    2006-07-01

    The discovery of high-temperature superconductors has strongly driven the development of suited thin film fabrication methods of complex oxides. One way is the adaptation of molecular beam epitaxy (MBE) for the growth of oxide materials. Another approach is the use of pulsed laser deposition (PLD) which has the advantage of good stoichiometry transfer from target to the substrate. Both techniques are used within this thesis. Epitaxial thin films of new materials are of course needed for future applications. In addition, the controlled synthesis of thin film matter which can be formed far away from thermal equilibrium allows for the investigation of fundamental physical materials properties. (orig.)

  18. Development of superconductors for fusion technology

    International Nuclear Information System (INIS)

    Wilson, M.N.; Walters, C.R.

    1976-04-01

    A report is presented on the development of a 10 4 Amp NbTi cryogenically stabilized superconductor. The long term objective was the construction of a superconducting toroidal field magnet for a post JET Tokamak experiment. The report is in sections entitled: magnet reference parameters; specific conductor designs; theoretical studies; experimental measurements; fabrication techniques; discussion, summary, conclusions and recommendations. (U.K.)

  19. Thin film superconductors and process for making same

    Science.gov (United States)

    Nigrey, P.J.

    1988-01-21

    A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

  20. Epitaxial growth of Fe-based superconductor thin films

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Sven; Haenisch, Jens; Holzapfel, Bernhard [Institut fuer Technische Physik, Karlsruher Institut fuer Technologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2016-07-01

    The Fe-based superconductors (FBS), discovered in 2008, are not only interesting for possible applications due to their large upper critical fields and low anisotropies, but also for basic understanding of unconventional superconductivity. With their properties, they constitute a link between the classic low-T{sub c} superconductors (low anisotropies, low thermal fluctuations, s-wave type symmetry) and the oxocuprates (T{sub c} up to 55 K, large H{sub c2}, unconventional pairing). Their multi-band nature reminds of MgB{sub 2}. We prepare thin films of FBS in the so called 122 family, namely Co- and P-doped BaFe{sub 2}As{sub 2} to investigate application relevant properties, such as critical current density J{sub c}, by pulsed laser deposition using a frequency-tripled Nd:YAG laser (λ = 355 nm). Microstructure and chemical composition will be investigated by XRD, AFM and SEM, and electrical transport using a 14 T PPMS. The results are compared to literature data on films grown at different wavelengths.

  1. Comparative Review on Thin Film Growth of Iron-Based Superconductors

    Directory of Open Access Journals (Sweden)

    Yoshinori Imai

    2017-07-01

    Full Text Available Since the discovery of the novel iron-based superconductors, both theoretical and experimental studies have been performed intensively. Because iron-based superconductors have a smaller anisotropy than high-Tc cuprates and a high superconducting transition temperature, there have been a lot of researchers working on the film fabrication of iron-based superconductors and their application. Accordingly, many novel features have been reported in the films of iron-based superconductors, for example, the fabrication of the epitaxial film with a higher Tc than bulk samples, the extraction of the metastable phase which cannot be obtained by the conventional solid state reaction, and so on. In this paper, we review the progress of research on thin film fabrications of iron-based superconductors, especially the four categories: LnFeAs(O,F (Ln = Lanthanide, AEFe2As2 (AE = Alkaline-earth metal, FeCh (Ch = Chalcogen, and FeSe monolayer. Furthermore, we focus on two important topics in thin films of iron-based superconductors; one is the substrate material for thin film growth on the iron-based superconductors, and the other is the whole phase diagram in FeSe1-xTex which can be obtained only by using film-fabrication technique.

  2. Computer graphic investigation on the epitaxial growth of superconductor films

    International Nuclear Information System (INIS)

    Miyamoto, A.; Iwamoto, S.; Inui, T.; Agusa, K.

    1989-01-01

    A mechanism of the epitaxial growth the oxide superconductor films has been investigated by using the computer graphics for the combination of orthorhombic Ba 2 YCu 3 O 7-x with substrate crystals such as SrTiO 3 MgO, and ZrO 2 . The (001) plane Ba 2 YCu 3 O 7-x with substrate crystals such as SrTiO 3 , MgO, and ZrO 2 . The (001) plane of Ba 2 YCu 3 O 7-x has been shown to fit the (100) plane of SrTiO 3 , MgO, and ZrO 2 . A crystallographic fit has also been proved between the (110) plane of Ba 2 YCu 3 O 7-x and the (110) plane of SrTiO 3 . These results are consistent with the experimental data about the epitaxial growth of the Ba 2 YCu 3 O 7-x films. Furthermore, detailed investigation of atomic arrangements has indicated some differences in the ionic interaction at the superconductor-substrate interface among SrTiO 3 , MgO, and ZrO 2 substrates. As for ZrO 2 (100) plane, for examples, ionic arrangements at the oxide layer is favorable only for the interaction with Y 3+ layer of Ba 2 YCu 3 O 7-x , while the Zr-O layer of ZrO 2 can interact with both Ba-O layer and Cu-O layer of Ba 2 YCu 3 O 7-x

  3. Functional development in density functional theory for superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sanna, Antonio; Gross, E.K.U.; Essenberger, Frank [Max Planck Institute of Microstructure Physics, Halle (Saale) (Germany)

    2015-07-01

    Density functional theory for superconductors (SCDFT) is a fully parameter-free approach to superconductivity that allows for accurate predictions of critical temperature and properties of superconductors. We report on the most recent extensions of the method, in particular the development of new functionals to: (1) incorporate in a correct fashion Migdal's theorem; (2) compute the excitation spectrum; (3) include spin-fluctuation mediated pairing Applications and predictions are shown for a set of materials, including conventional and unconventional superconductors.

  4. Development of high temperature superconductors having high critical current density

    International Nuclear Information System (INIS)

    Hong, Gye Wong; Kim, C. J.; Lee, H.G.; Kwon, S. C.; Lee, H. J.; Kim, K. B.; Park, J. Y.; Jung, C. H.

    2000-08-01

    Fabrication of high T c superconductors and its applications for electric power device were carried out for developing superconductor application technologies. High quality YBCO superconductors was fabricated by melt texture growth, top-seeded melt growth process and multi-seeded melt growth process and the properties was compared. The critical current density of the melt processed YBCO superconductors was about few 10,000 A/cm 2 and the levitation force was 50 N. The processing time needed for the growth of the 123 single grain was greatly reduced by applying multi-seeding without no significant degradation of the levitation force. The multi-seeded melt growth process was confirmed as a time-saving and cost-effective method for the fabrication of bulk superconductors with controlled crystallographic orientation

  5. Development of high temperature superconductors having high critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Gye Wong; Kim, C. J.; Lee, H.G.; Kwon, S. C.; Lee, H. J.; Kim, K. B.; Park, J. Y.; Jung, C. H

    2000-08-01

    Fabrication of high T{sub c} superconductors and its applications for electric power device were carried out for developing superconductor application technologies. High quality YBCO superconductors was fabricated by melt texture growth, top-seeded melt growth process and multi-seeded melt growth process and the properties was compared. The critical current density of the melt processed YBCO superconductors was about few 10,000 A/cm{sup 2} and the levitation force was 50 N. The processing time needed for the growth of the 123 single grain was greatly reduced by applying multi-seeding without no significant degradation of the levitation force. The multi-seeded melt growth process was confirmed as a time-saving and cost-effective method for the fabrication of bulk superconductors with controlled crystallographic orientation.

  6. Advanced nuclear materials development -Development of superconductor application technology-

    International Nuclear Information System (INIS)

    Hong, Kye Won; Lee, Heui Kyoon; Lee, Hoh Jin; Kim, Chan Joong; Jang, Kun Ik; Kim, Kee Baek; Kwon, Sun Chil; Park, Hae Woong; Yoo, Jae Keun; Kim, Jong Jin; Jang, Joong Chul; Yang, Suk Woo

    1995-07-01

    Fabrication of high Tc bulk superconductor and its application, fabrication of superconducting wire for electric power device and analysis for cryogenic system were carried out for developing superconductor application technologies for electric power system. High quality YBaCuO bulk superconductor was fabricated by controlling initial powder preparation process and prototype fly wheel energy storage device was designed basically. The superconducting levitation force measuring device was made to examine the property of prepared superconductor specimen. Systematic studies on the method of starting powder preparation, mechanical fabrication process, heat treatment condition and analysis of plastic deformation were carried out to increase the stability and reproducibility of superconducting wire. A starting powder with good reactivity and fine particle size was obtained by emulsion drying method. Ag/BSCCO tape with good cross sectional shape and Tc of 16,000 A/cm 2 was fabricated by applying CIP packing procedure. Multifilamentary wire with the Jc of approx. 10000 A/cm 2 was fabricated by rolling method using square billet as starting shape. The joining of the multifilament wire was done by etching and pressing process and showed 50% of joining efficiency. Analysis on the heat loss in cryostat for high Tc superconducting device was carried out for optimum design of the future cryogenic system. 126 figs, 14 tabs, 214 refs. (Author)

  7. Advanced nuclear materials development -Development of superconductor application technology-

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kye Won; Lee, Heui Kyoon; Lee, Hoh Jin; Kim, Chan Joong; Jang, Kun Ik; Kim, Kee Baek; Kwon, Sun Chil; Park, Hae Woong; Yoo, Jae Keun; Kim, Jong Jin; Jang, Joong Chul; Yang, Suk Woo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-07-01

    Fabrication of high Tc bulk superconductor and its application, fabrication of superconducting wire for electric power device and analysis for cryogenic system were carried out for developing superconductor application technologies for electric power system. High quality YBaCuO bulk superconductor was fabricated by controlling initial powder preparation process and prototype fly wheel energy storage device was designed basically. The superconducting levitation force measuring device was made to examine the property of prepared superconductor specimen. Systematic studies on the method of starting powder preparation, mechanical fabrication process, heat treatment condition and analysis of plastic deformation were carried out to increase the stability and reproducibility of superconducting wire. A starting powder with good reactivity and fine particle size was obtained by emulsion drying method. Ag/BSCCO tape with good cross sectional shape and Tc of 16,000 A/cm{sup 2} was fabricated by applying CIP packing procedure. Multifilamentary wire with the Jc of approx. 10000 A/cm{sup 2} was fabricated by rolling method using square billet as starting shape. The joining of the multifilament wire was done by etching and pressing process and showed 50% of joining efficiency. Analysis on the heat loss in cryostat for high Tc superconducting device was carried out for optimum design of the future cryogenic system. 126 figs, 14 tabs, 214 refs. (Author).

  8. Superconductors

    International Nuclear Information System (INIS)

    Ekin, J.W.

    1983-01-01

    This chapter attempts to provide an introductory guide to interpreting handbook data on practical, high-current, superconducting materials, principally for magnet applications. An overview is given of the properties and operational limits of superconductive materials, as well as techniques used to fabricate practical superconducting wires. Topics considered include critical temperature, critical magnetic field, Type I and Type II superconductors, upper critical field values for practical materials, the temperature dependence of critical field and upper critical field, critical current, critical current density values for practical materials, the measurement of critical current, composite fabrication, stability, ac losses, eddy current loss, hysteretic loss, mechanical properties, critical current degradation, and superconducting materals selection and composite design

  9. Low field critical currents and ac losses of thin film niobium--tin superconductors

    International Nuclear Information System (INIS)

    Howard, R.E.

    1977-01-01

    The results of a study of the low field critical current and ac loss properties of niobium-tin thin films and layered composites fabricated by electron-beam coevaporation are presented. Particular emphasis is placed upon determining the suitability of this material for use as a conductor in a superconducting power transmission line. Chapter I contains a summary of this work and its major results together with an introduction to the scientific and engineering concepts associated with a superconducting power transmission line. Chapter II is a discussion of the physics of current transport and the associated loss mechanisms in a type-II superconductor. Chapter III gives the details of the electron-beam coevaporation technique developed to fabricate the samples for this study. Also discussed in this chapter are the effects of the evaporation conditions on the growth morphology of the niobium-tin films. Chapter IV presents the details of the experimental techniques developed to measure the ac loss and critical current in these samples as a function of temperature. Chapter V shows the dependence of the critical current of these films and composites on temperature, magnetic field, and on the number of artificially introduced pinning centers in the layered composites. Experimental results are also presented concerning the stability of these conductors against flux jumps. Chapter VI is a discussion of the ac losses in these samples. Detailed comparisons are made between the measured loss and the predictions of the critical state model

  10. Ceramic superconductors II

    International Nuclear Information System (INIS)

    Yan, M.F.

    1988-01-01

    This volume compiles papers on ceramic superconductors. Topics include: structural patterns in High-Tc superconductors, phase equilibria of barium oxide superconductors, localized electrons in tetragonal YBa/sub 2/Cu/sub 3/O/sub 7-δ/, lattice and defect structure and properties of rare earth/alkaline earth-copper-oxide superconductors, alternate candidates for High-Tc superconductors, perovskite-structure superconductors; superconductive thin film fabrication, and superconductor/polymer composites

  11. Influence of superconductor film composition on adhesion strength of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2015-11-20

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare- earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples.

  12. Influence of superconductor film composition on adhesion strength of coated conductors

    International Nuclear Information System (INIS)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2016-01-01

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare-earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples. (paper)

  13. High-frequency applications of high-temperature superconductor thin films

    Science.gov (United States)

    Klein, N.

    2002-10-01

    High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz.

  14. High-frequency applications of high-temperature superconductor thin films

    International Nuclear Information System (INIS)

    Klein, N.

    2002-01-01

    High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz. (author)

  15. Growth of layered superconductor β-PdBi{sub 2} films using molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, N.V., E-mail: denisov@iacp.dvo.ru [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); Matetskiy, A.V.; Tupkalo, A.V. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); Zotov, A.V. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation); Department of Electronics, Vladivostok State University of Economics and Service, 690600 Vladivostok (Russian Federation); Saranin, A.A. [Institute of Automation and Control Processes FEB RAS, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation)

    2017-04-15

    Highlights: • Bulk β-PdBi{sub 2} is layered material with advanced properties of topological superconductor. • We present a method for growing β-PdBi{sub 2} films of a desired thickness. • Method utilizes MBE growth of β-PdBi{sub 2}, using Bi(111) film on Si(111) as a template. • Electronic and superconducting properties of the films are similar to those of bulk β-PdBi{sub 2}. - Abstract: Bulk β-PdBi{sub 2} layered material exhibits advanced properties and is supposed to be probable topological superconductor. We present a method based on molecular beam epitaxy that allows us to grow β-PdBi{sub 2} films from a single β-PdBi{sub 2} triple layer up to the dozens of triple layers, using Bi(111) film on Si(111) as a template. The grown films demonstrate structural, electronic and superconducting properties similar to those of bulk β-PdBi{sub 2} crystals. Ability to grow the β-PdBi{sub 2} films of desired thickness opens the promising possibilities to explore fascinating properties of this advanced material.

  16. Development of superconductor application technology -Advanced nuclear materials development-

    International Nuclear Information System (INIS)

    Hong, Gyee Won; Won, Dong Yeon; Lee, Hui Gyun; Lee, Ho Jin; Kim, Chan Joong; Park, Soon Dong; Kim, Uh Kon; Kim, Ki Baek; Kwon, Seon Chil; Kim, Yeon Soo; Lim, Dae Ho; Kim, Jong Jin

    1994-06-01

    Formation of oxide superconducting phase, fabrication of superconducting wire, design and fabrication of precise superconducting magnet were studied for developing superconductor application technique. The CeO 2 addition reduced the particle size of Y 2 BaCuO 5 trapped in the matrix after the melt-texture growth. The anomally is not observed at low temperature, which indicates that the oxygen deficiency is not effective flux pinning site at these temperature. Powder-in-powder method was developed to make superconducting wire. The stacking method for bonding the high Tc superconducting tapes was developed and proto-type current lead was fabricated by this technique. The precise superconducting coil was designed and fabricated. The required 4.02tesla was obtained on 139 A. The field deviation along the z axis of 5 cm was below 10 ppm when using 4 terms of shim cols. (Author)

  17. Superconductor thin films: topotactic corrosion mechanism of YBa2Cu3O7 with water vapor

    International Nuclear Information System (INIS)

    Boerner, R.; Schoellhorn, R.; Kabius, B.; Schubert, J.

    1995-01-01

    Corrosion in high-T c superconductors (HTSC) caused by water vapor is examined. HTSC thin films prepared using the laser ablation technique are shown to lose their superconducting properties due to the topotactic formation of a new hydroxylated phase which is a result of the corrosion. The mechanism of the corrosion process, which could be important in future applications of HTSC, is discussed. (orig.)

  18. Paradox in the crossover of the mechanisms causing the hysteresis in long, thin-film superconductors

    International Nuclear Information System (INIS)

    Dharmadurai, G.

    1980-01-01

    We point out an apparent paradox encountered in the region where the temperature of a voltage-sustaining film at the upper critical current crosses its T/sub c/ concerning the crossover of the two dominant heating mechanisms currently used to account for the lower critical currents observed on the hysteretic current-voltage characteristics of long, thin-film superconductors at varying high power levels. We explore a possible solution of this paradox by carefully examining the relevant heating models and available experimental observations

  19. Simplified expression for the minimum hotspot current in long, thin-film superconductors

    International Nuclear Information System (INIS)

    Dharmadurai, G.; Murthy, N.S.S.

    1979-01-01

    A generalization of the Skocpol--Beasley--Tinkham hotspot theory to include an approximate temperature dependence of the conductive heat transfer term of the heat flow equations clearly indicates that the role of the thermal conductivity of the material of the film is not reflected in the observed temperature dependence of the minimum current I/sub h/ required to sustain a hotspot in a long, thin-film superconductor. This observation leads to the derivation of a simplified expression for I/sub h/ valid for a wider range of bath temperatures

  20. Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shilpam; Amaladass, E.P. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Sharma, Neha [Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Harimohan, V. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Mani, Awadhesh, E-mail: mani@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2017-06-01

    Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples. - Highlights: • Thin films of molybdenum using DC sputtering have been deposited on glass. • Argon background pressure during sputtering was used to tune the crystallite sizes of films. • Correlation in deposition pressure, disorder and particle sizes has been observed. • Disorder tuned superconductor to insulator transition along with an intermediate metallic phase has been observed. • Enhancement of superconducting transition temperature and a dome shaped T{sub C} vs. deposition pressure phase diagram has been observed.

  1. Electron tunneling studies of ultrathin films near the superconductor-to-insulator transition

    International Nuclear Information System (INIS)

    Valles, J.M. Jr.; Garno, J.P.

    1994-01-01

    Electron tunneling measurements on ultrathin quench-condensed films near the superconductor-to-insulator (SI) transition reveal that the superconducting state degrades with increasing normal state sheet resistance, R □ , in a manner that depends strongly on film morphology. In homogeneously disordered films, the superconducting energy gap Δ 0 decreases continuously and appears to go to zero at the SI transition. In granular films the transport properties degrade while Δ 0 remains constant. Measurements in the normal state reveal disorder enhanced e - -e - interaction corrections to the density of states. These effects are strong and depend on morphology in a manner that is consistent with their playing an important role in driving the SI transition. (orig.)

  2. The preparation of Nb3Ge thin film superconductors in a UHV evaporation and sputter device

    International Nuclear Information System (INIS)

    Krevet, B.; Schauer, W.; Wuechner, F.

    1978-10-01

    Thin film techniques like evaporation or sputtering are remarkbly suitable to vary the metallurgical and physical properties of superconductors in a wide range. In the case of the A15-compound Nb 3 Ge only these preparation techniques allow us to produce a metastable pure phase in stoichiometric composition and to study its superconducting properties. The presen report describes two UHV-plants to produce superconducting films by multisource coevaporation and cosputtering. Of special importance are the constancy, monitoring and control of the evaporation rate, and the thermalization of the sputter components on the other hand. The experimental methods used are explained in detail and discussed together with the results of Nb 3 Ge films. With the preparation parameters suitably chosen both techniques allow to prepare reproducibly Nb 3 Ge films with 21 K transition temperature (onset); under optimized conditions Tc values up to 22.3 K have been reached. (orig.) [de

  3. Terahertz transmission of NbN superconductor thin film

    Czech Academy of Sciences Publication Activity Database

    Tesař, Roman; Koláček, Jan; Šimša, Zdeněk; Šindler, Michal; Skrbek, L.; Il'in, K.; Sieger, M.

    2010-01-01

    Roč. 470, č. 19 (2010), s. 932-934 ISSN 0921-4534 R&D Projects: GA ČR GA202/08/0326 Institutional research plan: CEZ:AV0Z10100521 Keywords : far- infrared transmission * NbN * superconducting film * magnetic vortices * terahertz waves Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.407, year: 2010

  4. High field superconductor development and understanding

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David C. [Florida State Univ., Tallahassee, FL (United States); Lee, Peter J. [Florida State Univ., Tallahassee, FL (United States); Tarantini, Chiara [Florida State Univ., Tallahassee, FL (United States)

    2014-09-28

    All present circular accelerators use superconducting magnets to bend and to focus the particle beams. The most powerful of these machines is the large hadron collider (LHC) at CERN. The main ring dipole magnets of the LHC are made from Nb-Ti but, as the machine is upgraded to higher luminosity, more powerful magnets made of Nb3Sn will be required. Our work addresses how to make the Nb3Sn conductors more effective and more suitable for use in the LHC. The most important property of the superconducting conductor used for an accelerator magnet is that it must have very high critical current density, the property that allows the generation of high magnetic fields in small spaces. Nb3Sn is the original high field superconductor, the material which was discovered in 1960 to allow a high current density in the field of about 9 T. For the high luminosity upgrade of the LHC, much higher current densities in fields of about 12 Tesla will be required. The critical value of the current density is of order 2600 A/mm2 in a field of 12 Tesla. But there are very important secondary factors that complicate the attainment of this critical current density. The first is that the effective filament diameter must be no larger than about 40 µm. The second factor is that 50% of the cross-section of the Nb3Sn conductor that is pure copper must be protected from any poisoning by any Sn leakage through the diffusion barrier that protects the package of niobium and tin from which the Nb3Sn is formed by a high temperature reaction. These three, somewhat conflicting requirements, mean that optimization of the conductor is complex. The work described in this contract report addresses these conflicting requirements. They show that very sophisticated characterizations can uncover the way to satisfy all 3 requirements and they also suggest that the ultimate optimization of Nb3Sn is still not yet in sight

  5. Tc depression and superconductor-insulator transition in molybdenum nitride thin films

    Science.gov (United States)

    Ichikawa, F.; Makise, K.; Tsuneoka, T.; Maeda, S.; Shinozaki, B.

    2018-03-01

    We have studied that the Tc depression and the superconductor-insulator transition (SIT) in molybdenum nitride (MoN) thin films. Thin films were fabricated by reactive DC magnetron sputtering method onto (100) MgO substrates in the mixture of Ar and N2 gases. Several dozen MoN thin films were prepared in the range of 3 nm < thickness d < 60 nm. The resistance was measured by a DC four-probe technique. It is found that Tc decreases from 6.6 K for thick films with increase of the normal state sheet resistance {R}{{sq}}{{N}} and experimental data were fitted to the Finkel’stein formula using the bulk superconducting transition temperature Tc 0 = 6.45 K and the elastic scattering time of electron τ = 1.6 × 10‑16 s. From this analysis the critical sheet resistance Rc is found about 2 kΩ, which is smaller than the quantum sheet resistance R Q. This value of Rc is almost the same as those for 2D NbN films. The value of τ for MoN films is also the similar value for NbN films 1.0 × 10‑16 s, while Tc 0 is different from that for NbN films 14.85 K. It is indicated that the mechanism of SIT for MoN films is similar to that of NbN films, while the mean free path ℓ for MoN films is larger than that for NbN films.

  6. Particulate generation during pulsed laser deposition of superconductor thin films

    International Nuclear Information System (INIS)

    Singh, R.K.

    1993-01-01

    The nature of evaporation/ablation characteristics during pulsed laser deposition strongly controls the quality of laser-deposited films. To understand the origin of particulates in laser deposited films, the authors have simulated the thermal history of YBa 2 Cu 3 O 7 targets under intense nanosecond laser irradiation by numerically solving the heat flow equation with appropriate boundary conditions. During planar surface evaporation of the target material, the sub-surface temperatures were calculated to be higher than the surface temperatures. While the evaporating surface of the target is constantly being cooled due to the latent heat of vaporization, subsurface superheating occurs due to the finite absorption depth of the laser beam. Sub-surface superheating was found to increase with decreasing absorption coefficient and thermal conductivity of the target, and with increasing energy density. The superheating may lead to sub-surface nucleation and growth of the gaseous phase which can expand rapidly leading to microexplosions and ''volume expulsion'' of material from the target. Experiments conducted by the authors and other research groups suggest a strong relation between degree of sub-surface superheating and particle density in laser-deposited films

  7. Effects of radiation damage in ion-implanted thin films of metal-oxide superconductors

    International Nuclear Information System (INIS)

    Clark, G.J.; Marwick, A.D.; Koch, R.H.; Laibowitz, R.B.

    1987-01-01

    The effects of ion implantation into thin films of the superconductor YBa 2 Cu 3 O/sub x/ have been studied. Using oxygen and arsenic ions, the superconducting transition temperature T/sub c/, the change in room-temperature electrical properties from conducting to insulating, and the crystalline to amorphous structural transition in the films were studied as a function of ion dose. The deposited energy required to change T/sub c/ was found to be 0.2 eV/atom, while 1--2 eV/atom was required to affect the room-temperature conductivity, and 4 eV/atom to render the film amorphous. This hierarchy of effects is discussed in terms of the damage mechanisms involved

  8. Deposition of high Tc superconductor thin films by pulsed excimer laser ablation and their post-synthesis processing

    International Nuclear Information System (INIS)

    Ogale, S.B.

    1992-01-01

    This paper describes the use of pulsed excimer laser ablation technique for deposition of high quality superconductor thin films on different substrate materials such as Y stabilized ZrO 2 , SrTiO 3 , LiNbO 3 , Silicon and Stainless Steels, and dopant incorporation during the film depositions. Processing of deposited films using ion and laser beams for realisation of device features are presented. 28 refs., 16 figs

  9. Investigation of thin films, heterostructures and devices of ceramic superconductors by means of high-resolution electron microscopy

    International Nuclear Information System (INIS)

    Jia Chunlin.

    1993-08-01

    In this thesis a systematic study of the microstructure of YBa 2 Cu 3 O 7 thin films is presented by means of high-resolution electron microscopy (HREM). Most of the efforts are focused on the characterization of heterostructures of superconducting YBa 2 Cu 3 O 7 and non-superconducting PrBa 2 Cu 3 O 7 and on YBa 2 Cu 3 O 7 films deposited on step-edge substrates. These specially designed structures exhibit a great potential for the electronic application of high-Tc superconductors and for the investigation of the basic electric properties of the YBa 2 Cu 3 O 7 superconductor. (orig.) [de

  10. Thin film production of ceramic high-Tc-superconductors (targets)

    International Nuclear Information System (INIS)

    1992-01-01

    Presently high-quality thin superconducting films having high T c 's may prepared by the sputtering technique. However, a large-area coating is required for an industrial application. One requirement is the availability of sputter targets with controlled and reproducible properties. By means of basic experiments with respect to powder processing, shaping and the densification process superconducting targets up to 200 mm in diameter were prepared in the Y-Ba-Cu-O- system. Additionally, targets from other systems with different geometries (e.g. ring targets) were prepared. These targets were submitted to the project partners as well as to other institutes and companies. During the course of this project the foundations for an industrial-type coating of large-area substrates were elaborated. (orig.). 9 refs., 5 tabs., 15 figs [de

  11. Kosterlitz-Thouless transition in high-Tc superconductor films

    International Nuclear Information System (INIS)

    Davis, L.C.; Beasley, M.R.; Scalapino, D.J.

    1990-01-01

    Dynamical theory for the polarization of bound vortex-antivortex pairs near the Kosterlitz-Thouless transition (T KT =88.4 K) has been applied to thin films of YBa 2 Cu 3 O 7 . Calculations show that the correct order of magnitude is predicted for the loss function ωG/c 2 at T KT , but the temperature dependence below the transition is wrong. The theoretical value drops much more rapidly with decreasing temperature than observed experimentally. Similar disagreement is found for the penetration depth λ(T). Estimates of the loss function at microwave frequencies show rather large effects near the critical temperature, but these become negligible by 80 K. The performance of microwave devices operating at liquid-N 2 temperature should not be degraded by vortex-antivortex pairs

  12. Research and development of basic technologies for the next generation industries. Summary of research achievements in fiscal 1992 (Research and development of superconductor materials and superconductor elements); Jisedai sangyo kiban gijutsu kenkyu kaihatsu 1992 nendo no kenkyu seika no gaiyo. Chodendo zairyo chodendo soshi no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-05-01

    With an objective to establish basic technologies, research and development has been carried out to make it possible to utilize high-temperature superconductor materials in terms of engineering in the fields of electronics and electric power. In the research on superconductor materials in fiscal 1992, it was discovered from measurements of temperature change in polarization dependent EXAFS in thin YBCO film grown on an MgO substrate that relative displacement in copper atoms in CuO{sub 2} plane and peak oxygen, and relative displacement in copper atoms on a primary chain and peak oxygen show apparent increase at the critical superconduction temperature. It was verified that this phenomenon does not occur in materials that do not show superconduction. In the research and development of superconductor elements, full-swing research has begun toward establishing the following technologies: process technologies for a substrate that meets requirement of surface flatness required in electronic elements, a superconductor thin film that assures uniformity in interface composition and the laminated thin film tunnel junction that combines the superconductor thin film, an inter-layer insulation film, and ultra-fine processing to suppress deterioration, and a tunnel element technology as a technology to put the above technologies together. (NEDO)

  13. Levitation force and magnetization in bulk and thin film high Tc superconductors

    International Nuclear Information System (INIS)

    Riise, A.B

    1998-04-01

    The authors present high-resolution measurements of the repulsive vertical force and its associated stiffness between a Nd-B-Fe magnet and a YBa 2 Cu 3 O 7-δ superconductor in cylindrical geometry. The results are compared with theoretical predictions. The calculations are based on a model in which the superconductor is assumed to be either a sintered granular material or consisting of grains embedded in a nonactive matrix so that only intragranular currents are important. The critical state model is applied to each grain individually and closed form expressions for both vertical force F z and stiffness are obtained in a configuration with cylindrical symmetry. The model explains all features of the experimental results in a consistent way. A good quantitative agreement has been obtained using only three adjustable parameters. Several central aspects of the phenomenon of magnetic levitation with high-T c superconductors are presented. High-resolution measurements are made of the repulsive vertical force and its associated stiffness as well as the horizontal stabilizing force and the stiffness governing lateral vibrations. The results obtained at 77 K using a granular YBa 2 Cu 3 O 7-δ sample and Nd-Fe-B magnet in a rectangular levitation configuration are compared with theoretical predictions. The calculations, which are based on the critical state model with the assumption that it applies to the grins individually, give closed-form expressions for all the measured quantities. It is concluded that the present model explains all features of the observations in a consistent way. Using only three adjustable parameters a good agreement exists also at a quantitative level. Experimental studies and theoretical modelling of the levitation force on a permanent magnet placed above a superconducting thin film are offered. It is shown that measurements of the levitation force is a simple and precise method to determine the critical current density in thin films

  14. Levitation force and magnetization in bulk and thin film high T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Riise, A.B

    1998-04-01

    The authors present high-resolution measurements of the repulsive vertical force and its associated stiffness between a Nd-B-Fe magnet and a YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconductor in cylindrical geometry. The results are compared with theoretical predictions. The calculations are based on a model in which the superconductor is assumed to be either a sintered granular material or consisting of grains embedded in a nonactive matrix so that only intragranular currents are important. The critical state model is applied to each grain individually and closed form expressions for both vertical force F{sub z} and stiffness are obtained in a configuration with cylindrical symmetry. The model explains all features of the experimental results in a consistent way. A good quantitative agreement has been obtained using only three adjustable parameters. Several central aspects of the phenomenon of magnetic levitation with high-T{sub c} superconductors are presented. High-resolution measurements are made of the repulsive vertical force and its associated stiffness as well as the horizontal stabilizing force and the stiffness governing lateral vibrations. The results obtained at 77 K using a granular YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} sample and Nd-Fe-B magnet in a rectangular levitation configuration are compared with theoretical predictions. The calculations, which are based on the critical state model with the assumption that it applies to the grins individually, give closed-form expressions for all the measured quantities. It is concluded that the present model explains all features of the observations in a consistent way. Using only three adjustable parameters a good agreement exists also at a quantitative level. Experimental studies and theoretical modelling of the levitation force on a permanent magnet placed above a superconducting thin film are offered. It is shown that measurements of the levitation force is a simple and precise method to determine the

  15. Cuprous sulfide as a film insulation for superconductors

    International Nuclear Information System (INIS)

    Wagner, G.R.; Uphoff, J.H.; Vecchio, P.D.

    1982-01-01

    The LCP test coil utilizes a conductor of forced-flow design having 486 strands of multifilametary Nb 3 Sn compacted in a stainless steel sheath. The impetus for the work reported here stemmed from the need for some form of insulation for those strands to prevent sintering during reaction and to reduce ac losses. The work reported here experimented with cuprous sulfide coatings at various coating rates and thicknesses. Two solenoids that were wound with cuprous sulfide-coated wires and heat-treated at 700 degrees C were found to demonstrate that the film is effective in providing turn-to-turn insulation for less than about 0.5V between turns. The sulfide layer provided a metal-semiconductor junction which became conducting at roughly 0.5V. Repeated cycling of the coil voltage in excess of that value produced no damage to the sulfide layer. The junction provided self-protection for the coil as long as the upper allowable current density in the sulfide was not exceeded. No training was apparent up to 6.4 T

  16. New Methods for Thin Film Deposition and First Investigations of the use of High Temperature Superconductors for Thin Film Cavities

    CERN Document Server

    Gustafsson, Anna; Vollenberg, Wilhelmus; Seviour, Rebecca

    2010-01-01

    Niobium thin film cavities have shown good and reliable performance for LEP and LHC, although there are limitations to overcome if this technique should be used for new accelerators such as the ILC. New coating techniques like High Power Impulse Magnetron Sputtering (HiPIMS) has shown very promising results and we will report on its possible improvements for Nb thin film cavity performance. Current materials used in accelerator Superconducting Radio Frequency (SRF) technologies operate at temperatures below 4 K, which require complex cryogenic systems. Researchers have investigated the use of High Temperature Superconductors (HTS) to form RF cavities, with limited success. We propose a new approach to achieve a high-temperature SRF cavity based on the superconducting ’proximity effect’. The superconducting proximity effect is the effect through which a superconducting material in close proximity to a non-superconducting material induces a superconducting condensate in the latter. Using this effect we hope...

  17. Experimental study of flux pinning in NbN films and multilayers: Ultimate limits on critical currents in superconductors

    International Nuclear Information System (INIS)

    Gray, K.E.; Kampwirth, R.T.; Capone, D.W. II; Murduck, J.M.

    1988-08-01

    A flux pinning model is presented which predicts the maximum critical current density attainable in superconductors. That such a limit must exist comes from the realization that flux pinning is strongest in regions of weak superconductivity, but these regions cannot carry a large supercurrent. Since the same regions within the superconductor cannot be used for both pinning and supercurrent conductions, there must be an optimum mix, leading to a maximum J/sub c/. Measurements on films and multilayers of NbN have verified many details of the model including anisotropy effects and a strong reduction in J/sub c/ for defect spacings smaller than the flux core diameter. In an optimized multilayer the pinning force reached /approximately/22% of the theoretical maximum. The implications of these results on the practical applications of NbN films and on the maximum critical current density in the new high temperature superconductors are also discussed. 24 refs., 4 figs

  18. A review and prospects for Nb3Sn superconductor development

    Science.gov (United States)

    Xu, Xingchen

    2017-09-01

    Nb3Sn superconductors have significant applications in constructing high-field (>10 T) magnets. This article briefly reviews development of Nb3Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (J c) is needed for future accelerator magnets. After a brief review of the development of Nb3Sn superconductors, the factors controlling J c are summarized and correlated with their microstructure and chemistry. The non-matrix J c of Nb3Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb3Sn phase in the non-matrix area, the upper critical field B c2, and the flux line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb3Sn fraction in subelements is ∼65%. Then, since B c2 is largely determined by the Nb3Sn stoichiometry, a thermodynamic/kinetic theory is presented to show what essentially determines the Sn content of Nb3Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb3Sn layers. Next, to improve flux pinning, previous efforts in this community to introduce additional pinning centers to Nb3Sn wires are reviewed, and an internal oxidation technique is described. Finally, prospects for further improvement of non-matrix J c of Nb3Sn conductors are discussed, and it is seen that the only opportunity for further significantly improving J c lies in improving flux pinning.

  19. The development of research on high temperature superconductors in Malaysia

    International Nuclear Information System (INIS)

    Shaari, A.H.; Hashim, M.; Dalimin, M.N.

    1989-01-01

    The background of the recent discovery of high-temperature oxide superconductor is given. This new discovery has driven scientists of different disciplines from many parts of the world into the race. Even those researchers from the developing countries are able to join the band wagon of the frontier research due to the convenience of working at temperatures well above that of liquid nitrogen. In Malaysia, some aspects of preparations and characterization of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O ceramics are studied. The 90 K transition temperature is observed in Y-Ba-Cu-O. (Auth.). 10 figs.; 5 refs

  20. Development of fabrication technique of bulk high superconductor

    International Nuclear Information System (INIS)

    Hong, Gye Won; Kim, Chang Joong; Kim, Ki Baik; Lee, Ho Jin; Lee, Hee Gyoun; Kwon, Sun Chil.

    1997-05-01

    In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBCO bulk superconductor with high mechanical strength and critical current density. In this project, plastic extrusion and melt process techniques were studied. The components materials for the current lead and the flywheel application were fabricated and their characteristics were investigated from the view point of microstructure and phase formation during heat treatment process. (author). 64 refs., 59 figs

  1. Noise measurements of YBa2Cu3O7 thin film high-temperature superconductors

    International Nuclear Information System (INIS)

    Hall, J.J.

    1992-01-01

    The characteristics of thin-film YBa2Cu3O7 superconductors were studied from the superconducting region through the transition region and into the normal region. The properties studied included the resistance-temperature, current-voltage, and electrical noise with concentration of measurements in the transition region. The resistance vs. temperature measurements show a zero resistance followed by a small rise in magnitude at the onset of resistance followed by a sharp increase until the resistance tapers off in the fully normal region. The a-axis films had a larger normal resistivity, a lower critical temperature, and a broader transition than the similar c-axis films. The current(I) - voltage(V) measurements were concentrated in the transition region. A power relation between I and V was found to be V varies as I a(T) where a(T) is temperature dependent starting high the onset of vortex formation, approaches 3 at the vortex unbinding temperature, and goes to 1 when fully normal. This behavior was predicted by the Kosterlitz-Thouless theory and was found experimentally in all four films measured. The current-induced electrical noise characteristics were measured for four samples varying in thickness and axis orientation. Each film exhibited a widely varying magnitude of the noise voltage spectral density (S V ) in the transition region with a leveling off when fully normal. The normalized noise (S V /V squared) showed a sharp decrease in magnitude from the onset of measurable noise continually decreasing until flattening out when fully normal. The a-axis films exhibited S V /V squared over 3 order of magnitude larger than the c-axis films in the transition and normal regions. The normalized temperature coefficient of resistance (beta) was plotted against S V /V squared on a log-log scale to see if the noise generated was due to temperature fluctuations (slope = 2)

  2. Long-ranged interactions in thin TiN films at the superconductor-insulator transition?

    Energy Technology Data Exchange (ETDEWEB)

    Kronfeldner, Klaus; Strunk, Christoph [Institute for Experimental and Applied Physics, University of Regensburg (Germany); Baturina, Tatyana [A.V. Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk (Russian Federation)

    2015-07-01

    We measured IV-characteristics and magnetoresistance of square TiN-films in the vicinity of the disorder-tuned superconductor-insulator transition (SIT) for different sizes (5 μm to 240 μm). While the films are superconducting at zero magnetic field, at finite fields a SIT occurs. The resistance shows thermally activated behaviour on both sides of the SIT. Deep in the superconducting regime the activation energy grows linear with the sample size as expected for a size-independent critical current density. Closer to the SIT the activation energy becomes clearly size independent. On the insulating side the magnetoresistance maximum and the activation energy both grow logarithmically with sample size which is consistent with a size-limited charge BKT (Berezinskii-Kosterlitz-Thouless) scenario. In order to test for the presence of long-ranged interactions in our films, we investigate the influence of a topgate. It is expected to screen the possible long-ranged interactions as the distance of the film to the gate is much shorter than the electrostatic screening length deduced from the size-dependent activation energy.

  3. Superconductor-Metal-Insulator transition in two dimensional Ta thin Films

    Science.gov (United States)

    Park, Sun-Gyu; Kim, Eunseong

    2013-03-01

    Superconductor-insulator transition has been induced by tuning film thickness or magnetic field. Recent electrical transport measurements of MoGe, Bi, Ta thin films revealed an interesting intermediate metallic phase which intervened superconducting and insulating phases at certain range of magnetic field. Especially, Ta thin films show the characteristic IV behavior at each phase and the disorder tuned intermediate metallic phase [Y. Li, C. L. Vicente, and J. Yoon, Physical Review B 81, 020505 (2010)]. This unexpected metallic phase can be interpreted as a consequence of vortex motion or contribution of fermionic quasiparticles. In this presentation, we report the scaling behavior during the transitions in Ta thin film as well as the transport measurements in various phases. Critical exponents v and z are obtained in samples with wide ranges of disorder. These results reveal new universality class appears when disorder exceeds a critical value. Dynamical exponent z of Superconducting sample is found to be 1, which is consistent with theoretical prediction of unity. z in a metallic sample is suddenly increased to be approximately 2.5. This critical exponent is much larger than the value found in other system and theoretical prediction. We gratefully acknowledge the financial support by the National Research Foundation of Korea through the Creative Research Initiatives.

  4. High field superconductor development and understanding project, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, David C.; Lee, Peter J.

    2009-07-15

    Over 25 years the Applied Superconductivity Center at the University of Wisconsin-Madison provided a vital technical resource to the High Energy Physics community covering development in superconducting strand for HEP accelerator magnet development. In particular the work of the group has been to develop the next generation of high field superconductors for high field application. Grad students Mike Naus, Chad Fischer, Arno Godeke and Matt Jewell improved our understanding of the microstructure and microchemistry of Nb3Sn and their impact on the physical and mechanical properties. The success of this work has led to the continued funding of this work at the ASC after it moved to the NHMFL and also to direct funding from BNL for some aspects of Nb3Sn cable evaluation.

  5. Organic superconductors

    International Nuclear Information System (INIS)

    Bulaevskij, L.N.; Shchegolev, I.F.

    1986-01-01

    Main achievements in creating new organic conducting materials - synthetic metals and superconductors, are considered. The processes of superconductivity occurrence in organic materials are discussed. It is shown that conjugated bonds between C and H atoms in organic molecules play an important role in this case. At present ''crystal direction'' in organic superconductor synthesis is mainly developed. Later on, organic superconductor crystals are supposed to be introduced into usual polymers, e.g. polyethylene

  6. Femosecond dynamics of quasi-particles in YBa2Cu3O7-δ superconductor films

    International Nuclear Information System (INIS)

    Han, S.G.; Vardeny, Z.V.; Symko, O.G.; Koren, G.

    1991-01-01

    This paper reports on the transient electronic response of YBa 2 Cu 3 O 7-δ epitaxially grown HT c superconductor thin films in the femtosecond time domain, using transient photoinduced reflectivity (ΔR) with 60 fsec time resolution. For temperatures T > T c only a bolometric signal was observed with ΔR > O. For T c ΔR < O with a temperature dependent rise time of order 300 fsec followed by a relaxation (of order 3 psec) into a state with Δ are explained in terms of quasi-particle (QP) electronic response giving ΔR < O. Thus the femtosecond rise time is interpreted as avalanche multiplication of QP across the gap 2Δ and the subsequent picosecond relaxation as QP recombination. The QP optical response is explained within the two fluid model

  7. High-Tc film development for electronic applications

    International Nuclear Information System (INIS)

    Talvacchio, J.; Wagner, G.R.

    1990-01-01

    In this paper, the authors describe the requirements and status of high-T c superconductor (HTS) films for the development of electronic applications with an emphasis on passive microwave devices. One of the most general requirements, a low rf Surface resistance relative to Cu, has been achieved in films of several different HTS compounds. However the best films, made of YBa 2 Cu 3 O 7 (YBCO) by any one of several techniques, have in common a residual surface resistance that is much greater than predicted by conventional superconductivity theory. Improvement in films is also limited by the current size and selection of single-crystal substrate materials. Other issues that must be resolved to develop a full integrated circuit technology for HTS are substrate heating during film deposition, deposited epitaxial insulators, and determination of which interfaces in a multilevel circuit must be formed in situ

  8. In-Situ Synchrotron X-ray Study of the Phase and Texture Evolution of Ceria and Superconductor Films Deposited by Chemical Solution Method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude; He, Dong

    2012-01-01

    In situ synchrotron x-ray diffraction is used to study the phase and texture formation of ceria based films and superconductor films deposited by the chemical solution method on technical substrates. Combined analysis using in situ synchrotron x-ray diffraction, thermogravimetry/differential ther......In situ synchrotron x-ray diffraction is used to study the phase and texture formation of ceria based films and superconductor films deposited by the chemical solution method on technical substrates. Combined analysis using in situ synchrotron x-ray diffraction, thermogravimetry...

  9. Possibility of the vortex-antivortex transition temperature of a thin-film superconductor being renormalized by disorder

    International Nuclear Information System (INIS)

    Hebard, A.F.; Kotliar, G.

    1989-01-01

    The universal relation between the Kosterlitz-Thouless transition temperature T/sub c/ and the superfluid sheet density of thin-film superconductors with mean-field transition temperature T/sub c/ 0 results in a monotonically decreasing dependence of the ratio T/sub c//T/sub c0/ on the normal-state sheet resistance R/sub n/. Ambiguity in the experimental definition of R/sub n/ in highly disordered thin-film superconductors is addressed by reexamining previously published data on amorphous composite In/InO/sub x/ films. Arguments are presented in favor of using the zero-temperature value of R/sub n/, a quantity obtained by extrapolation. The dependence of T/sub c//T/sub c0/ on R/sub n/ that results from such a choice is in agreement with theory for dirty superconductors and thus suggests that additional corrections to T/sub c/ in the presence of extreme disorder are not required

  10. Development of materials for high temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Houlton, R.J.; Reagor, D.W.; Hawley, M.E.; Springer, K.N.; Jia, Q.X.; Mombourquette, C.B.; Garzon, F.H.; Wu, X.D.

    1994-01-01

    We have conducted a systematic optimization of deposition parameters for fabrication of multilayered oxide films to be used in the development of high temperature superconducting SNS Functions. These films were deposited by off-axis sputtering using a custom fabricated multi-gun planar magnetron system. Each material and the various combinations of materials were optimized for epitaxial lattice match, crystal quality, film uniformity, electrical properties, and surface microstructure. In addition to the standard procedures commonly used to sputter deposit epitaxial oxide films, a variety of insitu and exsitu procedures were used to produce high quality multilayer devices, including varying the nucleation temperature from the actual film growth temperature, location of the substrate during the deposition process, constant rotation of the substrate, and timing of the oxygen anneal. The unprocessed films and devices in process were characterized with Atomic Force Microscopy and Scanning Tunneling Microscopy as well as other common materials characterization techniques. Completed multilayer devices were patterned and packaged for electrical characterization. Relation between material properties and electrical characteristics is discussed

  11. Development of materials for high temperature superconductor Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Houlton, R.J.; Reagor, D.W.; Hawley, M.E.; Springer, K.N.; Jia, Q.X.; Mombourquette, C.B.; Garzon, F.H.; Wu, X.D.

    1994-10-01

    We have conducted a systematic optimization of deposition parameters for fabrication of multilayered oxide films to be used in the development of high temperature superconducting SNS Functions. These films were deposited by off-axis sputtering using a custom fabricated multi-gun planar magnetron system. Each material and the various combinations of materials were optimized for epitaxial lattice match, crystal quality, film uniformity, electrical properties, and surface microstructure. In addition to the standard procedures commonly used to sputter deposit epitaxial oxide films, a variety of insitu and exsitu procedures were used to produce high quality multilayer devices, including varying the nucleation temperature from the actual film growth temperature, location of the substrate during the deposition process, constant rotation of the substrate, and timing of the oxygen anneal. The unprocessed films and devices in process were characterized with Atomic Force Microscopy and Scanning Tunneling Microscopy as well as other common materials characterization techniques. Completed multilayer devices were patterned and packaged for electrical characterization. Relation between material properties and electrical characteristics is discussed

  12. Method of depositing thin films of high temperature Bi-Sr-Ca-Cu-O-based ceramic oxide superconductors

    International Nuclear Information System (INIS)

    Budd, K.D.

    1991-01-01

    This patent describes a method. It comprises preparing a liquid precursor of a Bi-Sr-Ca-Cu-O- based ceramic oxide superconductor phase, wherein the liquid precursor comprises an alkoxyalkanol, copper acrylate, strontium acrylate, bismuth nitrate, and calcium nitrate, wherein the liquid precursor has a cation ratio sufficient to form the desired stoichiometry in the ceramic oxide superconductor phase when the liquid precursor is heated to a temperature and for a time sufficient to provide the desired ceramic oxide superconductor phase, and wherein the copper acrylate, strontium acrylate, bismuth nitrate, and calcium nitrate are mutually soluble in the alkoxyalkanol; applying the liquid precursor to a substrate, wherein the substrate is one of an oxide ceramic, a metal selected from the group consisting of Ag and Ni, and Si; and heating the substrate in an oxygen-containing atmosphere with the liquid precursor applied thereon to a temperature and for a time sufficient to form a thin film comprising at least one Bi-Sr- Ca-Cu-O-based high temperature ceramic oxide superconductor phase

  13. Ion implantation as a method of studying inhomogeneities in superconductors: results for indium films with embedded helium particles

    International Nuclear Information System (INIS)

    Fogel, N.Ya.; Moshenski, A.A.; Dmitrenko, I.M.

    1978-01-01

    The paper considers the applicability of ion implantation into superconductors to investigate inhomogeneity effects on their macroscopic properties. Noble-gas-ion implantation into thin superconducting films is shown to be a unique means of systematically studying these effects in a single sample. Data demonstrating the effect of inhomogeneities on the critical current, Isub(c) in the mixed state and phase-transition smearing in He + -ion-irradiated indium films are presented. First, experimental evidence was obtained to support the Larkin-Ovchinnikov theory which relates Isub(c) and the phase-transition smearing to inhomogeneities of the electron-electron interaction constant g(r) and the electron mean free path (r). Results are presented for parallel critical field anomalies in He-implanted indium films which are due to an implantation-induced anisotropy of xi(t). Changes in the critical parameters for the film resulting from the implantation are compared to structural changes. (Auth.)

  14. Development of high temperature superconductors for magnetic field applications

    International Nuclear Information System (INIS)

    Larbalestier, D.C.

    1991-01-01

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbations to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development

  15. Magnetic field induced superconductor-insulator transitions for ultra-thin Bi films on the different underlayers

    International Nuclear Information System (INIS)

    Makise, K; Kawaguti, T; Shinozaki, B

    2009-01-01

    This work shows the experimental results of the superconductor-insulator (S-I) transition for ultra-thin Bi films in magnetic fields. The quench-condensed (q-c) Bi film onto insulating underlayers have been interpreted to be homogeneous. In contrast, the Bi film without underlayers has been regarded as a granular film. The electrical transport properties of ultra-thin metal films near the S-I transition depend on the structure of the film. In order to confirm the effect of the underlayer to the homogeneity of the superconducting films, we investigate the characteristics of S-I transitions of q-c nominally homogeneous Bi films on underlayers of two insulating materials, SiO, and Sb. Under almost the same deposition condition except for the material of underlayer, we prepared the Bi films by repeating the additional deposition and performed in-situ electrical measurement. It is found that the transport properties near the S-I transitions show the remarkable difference between two films on different underlayers. As for Bi films on SiO, it turned out that the temperature dependence of resistance per square R sq (T) of the field-tuned transition and the thickness-tuned transition shows similar behavior; it was a thermally activated form. On the other hand, the R sq (T) of Bi films on Sb for thickness-tuned S-I transition showed logarithmic temperature dependence, but that for field-tuned S-I transition showed a thermally activated form.

  16. Q factor of megahertz LC circuits based on thin films of YBaCuO high-temperature superconductor

    Science.gov (United States)

    Masterov, D. V.; Pavlov, S. A.; Parafin, A. E.

    2008-05-01

    High-frequency properties of resonant structures based on thin films of YBa2Cu3O7 δ high-temperature superconductor are studied experimentally in the frequency range 30 100 MHz. The structures planar induction coils with a self-capacitance fabricated on neodymium gallate and lanthanum aluminate substrates. The unloaded Q factor of the circuits exceeds 2 × 105 at 77 K and 40 MHz. Possible loss mechanisms that determine the Q factor of the superconducting resonant structures in the megahertz range are considered.

  17. Switching process between bistable positons of multiquantum flux tubes in a thin-film type I superconductor

    International Nuclear Information System (INIS)

    Parisi, J.; Huebener, R.P.; Muhlemeier, B.

    1983-01-01

    A superconducting memory device based on a bistable vortex position represents an interesting storage medium for future Josephson computers. In order to study the operational mode of such a single-flux quantum memory cell, we use as a model system multiquantum flux tubes in a thin-film type I superconductor (Pb). By employing high-resolution stroboscopic magnetooptical flux detection, we are able to globally visualize both spatial and temporal behavior of rapidly switching individual flux tubes. All experimental results agree reasonably well with theoretical model considerations of the energy balance during the elementary switching process

  18. Development of application technique of bulk high-Tc superconductor

    International Nuclear Information System (INIS)

    Hong, Kye Won; Kim, Chan Joong; Kim, Kee Baek; Kwon, Sun Chil; Won, Dong Yun; Lee, Hoh Jin; Lee, Heui Kyoon; Jang, Kun Ik; Yang, Suk Woo

    1995-03-01

    YBCO-Ag composite superconductors were prepared by extrusion using inorganic binder materials. In the case of the undoped 1-2-3 sample with a dia. of 2.5 mm, critical current density (Jc) was 150 A/cm 2 and current density (Ic) was 10 amps. In the case of the sample with a die. of 4.5 mm, meanwhile, Jc and Ic were 50 A/cm 2 and 32 amps, respectively. Influence of BaCeO 3 addition on magnetization characteristics of melt-textured Y-Ba-Cu-O superconductor was investigated. The variation of magnetization behavior due to the addition of BaCeO 3 is discussed on the basis of the related microstructures. 37 figs, 1 tab, 56 refs. (Author)

  19. Advanced high temperature superconductor film-based process using RABiTS

    International Nuclear Information System (INIS)

    Goyal, A.; Hawsey, R.A.; Hack, J.; Moon, D.

    2000-01-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corporation (Contractor), Managing contractor for Oak Ridge National Laboratory (ORNL) and Midwest Superconductivity, Inc. (MSI) and Westinghouse Science and Electric Company (WEC) was to develop the basis for a commercial process for the manufacturing of superconducting tape based on the RABiTS technology developed at ORNL. The chosen method for deposition of YBCO films on RABiTS was Metal Organic chemical Vapor Deposition (MOCVD)

  20. Effects of α-particle beam irradiation on superconducting properties of thin film MgB2 superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Bum; Duong, Pham van; Ha, Dong Hyup; Oh, Young Hoon; Kang, Won Nam; Chai, Jong Seo [Sungkunkwan Univeversity, Suwon (Korea, Republic of); Hong, Seung Pyo; Kim, Ran Young [Kore Institute of Radiological and Medical Science, Seoul (Korea, Republic of)

    2016-06-15

    Superconducting properties of thin film MgB2 superconductors irradiated with 45 MeV α-particle beam were studied. After the irradiation, enhancement of the critical current density and pinning force was observed, scaling close to strong pinning formula. Double logarithmic plots of the maximum pinning force density with irreversible magnetic field show a power law behavior close to carbon-doped MgB2 film or polycrystals. Variation of normalized pinning force density in the reduced magnetic field suggests scaling formulas for strong pinning mechanism like planar defects. We also observed a rapid decay of critical current density as the vortex lattice constant decreases, due to the strong interaction between vortices and increasing magnetic field.

  1. Field-tuned superconductor-insulator transitions and Hall resistance in thin polycrystalline MoN films

    Science.gov (United States)

    Makise, Kazumasa; Ichikawa, Fusao; Asano, Takayuki; Shinozaki, Bunju

    2018-02-01

    We report on the superconductor-insulator transitions (SITs) of disordered molybdenum nitride (MoN) thin films on (1 0 0) MgO substrates as a function of the film thickness and magnetic fields. The T c of the superconducting MoN films, which exhibit a sharp superconducting transition, monotonically decreases as the normal state R sq increases with a decreasing film thickness. For several films with different thicknesses, we estimate the critical field H c and the product zν  ≃  0.6 of the dynamical exponent z and the correlation length exponent ν using a finite scaling analysis. The value of this product can be explained by the (2  +  1) XY model. We found that the Hall resistance ΔR xy (H) is maximized when the magnetic field satisfies H HP(T) \\propto |1  -  T/T C0| in the superconducting state and also in the normal states owning to the superconducting fluctuation corresponding to the ghost critical magnetic field. We measured the Hall conductivity δσ xy (H)  =  σ xy (H)  -  σ xyn and fit the Gaussian approximation theory for δσ xy (H) to the experimental data. Agreement between the data and the theory beyond H c suggests the survival of the Cooper pair in the insulating region of the SIT.

  2. Intermetallic superconductors - The state of development in 1991

    International Nuclear Information System (INIS)

    Forsyth, E.

    1991-01-01

    The commercial fabrication of intermetallic superconductors has reached a high degree of maturity in the past thirty years. The only significant, commercial requirement for superconducting wire is the construction of magnetic resonance imaging (MRI) devices for medical diagnosis. In addition to this demand there are one-time projects such as a high energy particle accelerators which often need considerable quantities of superconducting material over the few years of construction. R and D projects also provide a fluctuating market for superconducting materials, in the past the projects have included power apparatus such as generators, motors, energy storage and transmission cables, and magnets for experimental fusion reactors. Superconducting magnetically levitated trains have undergone full scale trials in Japan and Germany. This is by no means a comprehensive list of all the possible applications. Virtually all the devices requiring a magnetic field to be produced by superconducting windings have used NbTi wire, but a few experimental Nb 3 Sn high field magnets have been constructed. In the case of these materials commercial vendors can provide a high degree of quality assurance on such characteristics as critical current, coupling effects and mechanical tolerances. This paper discusses the market for intermetallic and ceramic superconductors, their fabrication properties, applications, and cost

  3. Substitutions in cation Nd/Ba subsystem in thin films of high-temperature superconductor NdBa2Cu3Oy

    International Nuclear Information System (INIS)

    Mozhaev, P.B.; Komissinskij, F.V.; Ivanov, Z.G.; Ovsyannikov, G.A.

    2000-01-01

    Thin films of the Nd 1+x Ba 2-x Cu 3 O y (NBCO) high-temperature superconductor with various neodymium and barium ratio are obtained through the method of combined laser spraying of targets with different elements composition. The films with neodymium excess (x >0) had low density of particles on the surface and roughness, however the critical temperature decreased with growth of x. The films with barium excess (x z particles. The NbCO structure and superconducting properties demonstrate strong dependence on the conditions of the films saturation with oxygen [ru

  4. Thermal treatment influence on the preparation of BPSCCO superconductor thin films

    International Nuclear Information System (INIS)

    Torsoni, Guilherme Botega; Carvalho, Claudio Luiz

    2011-01-01

    Full text: Nowadays, with the evolution of technology, superconducting thin films application in microelectronics is essential for production of some equipment with reduced size and low energy consumption. There are different ways to prepare thin films, however deposition in liquid phase have received special attention, whose main features are: fast deposition, reduced cost and the possibility of covering large areas. Basically, the method consists to deposit a polymeric precursor solution, with synthesis based on the methodology developed by M. Pechini, on a crystalline substrate using a spin coating equipment also called spinner. In the deposition process by spinner, must be considered some physical parameters, such as, rotation speed, viscosity solution, substrate acceleration and rotating time, evaporation rate and temperature solution. Immediately after the deposition, the material is submitted to different thermal treatments, this consists of two stages, in other words, calcination and sintering stages. The objective of the first stage is to remove the organic compounds, which can be done at temperatures around 500 deg C - 600 deg C, and the other stage, it can be done around 750 deg C and 850 deg C, it means the same interval of phase formation. In this work, films were made with five layers of deposition on Si substrate in three different sintering temperatures, 750, 800 and 850 deg C and it was studied the evolution of the films due to thermal treatment applied. Characterizations were made by x-ray diffraction, microscopy by field emission gun and energy dispersive x-ray (EDS). X-ray diffractograms shown that 2212 phase was obtained in all samples submitted to different temperatures, for higher sintering temperature was not observed any kind of crystalline planes orientation and the electron microscopy and EDS showed that the films are also more homogeneous. (author)

  5. Femosecond dynamics of quasi-particles in YBa sub 2 Cu sub 3 O sub 7 minus. delta. superconductor films

    Energy Technology Data Exchange (ETDEWEB)

    Han, S.G.; Vardeny, Z.V.; Symko, O.G. (Utah Univ., Salt Lake City, UT (United States). Dept. of Physics); Koren, G. (Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Physics)

    1991-03-01

    This paper reports on the transient electronic response of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} epitaxially grown HT{sub c} superconductor thin films in the femtosecond time domain, using transient photoinduced reflectivity ({Delta}R) with 60 fsec time resolution. For temperatures T {gt} T{sub c} only a bolometric signal was observed with {Delta}R {gt} O. For T {lt} T{sub c} {Delta}R {lt} O with a temperature dependent rise time of order 300 fsec followed by a relaxation (of order 3 psec) into a state with {Delta} are explained in terms of quasi-particle (QP) electronic response giving {Delta}R {lt} O. Thus the femtosecond rise time is interpreted as avalanche multiplication of QP across the gap 2{Delta} and the subsequent picosecond relaxation as QP recombination. The QP optical response is explained within the two fluid model.

  6. Development of Field Angle Resolved Specific Heat Measurement System for Unconventional Superconductors

    International Nuclear Information System (INIS)

    Kitamura, Yasuhiro; Matsubara, Takeshi; Machida, Yo; Izawa, Koichi; Onuki, Yoshichika; Salce, Bernard; Flouquet, Jacques

    2015-01-01

    We developed a measurement system for field angle resolved specific heat under multiple extreme conditions at low temperature down to 50 mK, in magnetic field up to 7 T, and under high pressure up to 10 GPa. We demonstrated the performance of our developed system by measuring field angle dependence of specific heat of pressure induced unconventional superconductor CeIrSi 3

  7. New Developments in the Theory of HTSC [High Temperature Superconductors

    Science.gov (United States)

    Abrikosov, A.A.

    1994-09-01

    The superconductor is supposed to consist of alternating layers of two kinds: (1) layers with an attractive electron interaction and an effective mass of usual magnitude, (2) layers without interaction and with a large effective mass. The overlap between the layers is assumed to be small, its energy, t, being much less than {Delta}. It is shown, that such a model explains the most peculiar property found in experiments on electronic Raman light scattering in BSCCO 2212: different threshold values for the Raman satellite measured at two different polarizations of the incident and scattered light. The tunneling conductance G(V)= dJ/dV is analyzed for the same model. In order to fit the qualitative features of experimental data, it is assumed that the tunneling probability to the normal layers is much less, than to the superconducting layers. The conductance is calculated for the case t{much_lt}{Delta}. A brief analysis is given for the case t{approximately}{Delta}, which proves that such an assumption definitely contradicts the experimental data for BSCCO. The possible nature of the electronic states in the normal layers is discussed. In connection with the experimental discovery (angle resolved photoemission spectroscopy, ARPES) of the extended saddle point singularities in the electron spectrum of a variety of HTSC consequences are derived for T{sub c} and {Delta} in a simple model. A large enhancement of superconductivity is possible if the singularity has a sufficient extension and is located close to the Fermi energy. In order to explain the anisotropy of the energy gap, observed in ARPES experiments, on the basis of the "extended saddle point singularities" an assumption is done that the Coulomb interactions are weakly screened, i.e. the Debye screening radius is much larger than the lattice period; this makes the electron interaction long ranged (E-L model).

  8. Recent advances in high-temperature superconductor wire fabrication and applications development

    International Nuclear Information System (INIS)

    Hull, J.R.; Uherka, K.L.

    1992-01-01

    In this paper, recent advances in fabrication of high-temperature superconductor wires are summarized and detailed discussion is provided on developments in near- and intermediate-term applications. Near-term applications, using presently obtainable current densities, include liquid-nitrogen depth sensors, cryostat current leads, and magnetic bearings. Intermediate-term applications, using current densities expected to be available in the near future, include fault-current limiters and short transmission lines

  9. Towards Faster FEM Simulation of Thin Film Superconductors: A Multiscale Approach

    DEFF Research Database (Denmark)

    Rodriguez Zermeno, Victor Manuel; Mijatovic, Nenad; Træholt, Chresten

    2011-01-01

    This work presents a method to simulate the electromagnetic properties of superconductors with high aspect ratio such as the commercially available second generation superconducting YBCO tapes. The method is based on a multiscale representation for both thickness and width of the superconducting...... at considerable lower computational time. Several test cases were simulated including transport current, externally applied magnetic field and a combination of both. The results are in good agreement with recently published numerical simulations. The computational time to solve the present multiscale approach...

  10. Selective laser pyrolysis of metallo-organics as a method of forming patterned thin film superconductors

    International Nuclear Information System (INIS)

    Mantese, J.V.; Catalan, A.B.; Sell, J.A.; Meyer, M.S.; Mance, A.M.

    1990-01-01

    This patent describes a method for forming patterned films of superconductive materials forming a solution from the neodecanoates of yttrium, barium and copper. The neodecanoates forming an oxide mixture exhibiting superconductive properties upon subsequent thermal decompositions wherein the oxide mixture is characterized by a ratio of yttrium:barium:copper of approximately 1:2:4, the solution comprising an organic solvent such as xylene; adding to the solution an appropriate dye, depositing a film of the solution having the dye onto a strontium titanate substrate; exposing selective regions of the film with an Argon laser emitting the wavelength of light, such that the exposed regions of the film become insoluble in the xylene; immersing the film into the xylene so that the soluble; unexposed regions of the film are removed from the substrate; heating the film to thermally decompose the neodecanoates into a film containing yttrium, barium and copper oxides; to promote recrystallization and grain growth of the metal oxides within the film and induce a change therein by which the film exhibits superconducting properties

  11. Development and exploration of potential routes of discovery of new superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Xiao [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    This thesis summarizes our efforts to develop and explore potential routes for the discovery of new superconductors. The development of viable solutions for sulfur-bearing compounds is presented. It also provides the details of searching for quantum critical points (QCPs) and possible superconductors by suppressing ferromagnetic states via chemical substitution and the application of pressure. The ferromagnetism in La(VxCr1-x)Ge3 was successfully suppressed by pressure, and, in addition, a potential QCP at ambient pressure was discovered for x = 0.16. On the other hand, the La(VxCr1-x)Sb3 series is likely to evolve into new magnetic state with V-substitution with the Cr-based magnetism appearing to be more local-moment like than for the case of LaCrGe3. We also performed detailed characterization on BaSn5 superconductor, giving further understanding of its superconducting state, and on R3Ni2-xSn7 and RNi1-xBi2±y series putting to rest spurious claims of superconductivity.

  12. A new approach to the inverse problem for current mapping in thin-film superconductors

    Science.gov (United States)

    Zuber, J. W.; Wells, F. S.; Fedoseev, S. A.; Johansen, T. H.; Rosenfeld, A. B.; Pan, A. V.

    2018-03-01

    A novel mathematical approach has been developed to complete the inversion of the Biot-Savart law in one- and two-dimensional cases from measurements of the perpendicular component of the magnetic field using the well-developed Magneto-Optical Imaging technique. Our approach, especially in the 2D case, is provided in great detail to allow a straightforward implementation as opposed to those found in the literature. Our new approach also refines our previous results for the 1D case [Johansen et al., Phys. Rev. B 54, 16264 (1996)], and streamlines the method developed by Jooss et al. [Physica C 299, 215 (1998)] deemed as the most accurate if compared to that of Roth et al. [J. Appl. Phys. 65, 361 (1989)]. We also verify and streamline the iterative technique, which was developed following Laviano et al. [Supercond. Sci. Technol. 16, 71 (2002)] to account for in-plane magnetic fields caused by the bending of the applied magnetic field due to the demagnetising effect. After testing on magneto-optical images of a high quality YBa2Cu3O7 superconducting thin film, we show that the procedure employed is effective.

  13. Critical temperature gradient and critical current density in thin films of a type I superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Heubener, R P

    1968-12-16

    Measurements of the critical temperature gradient and the critical current density in superconducting lead films in a transverse magnetic field indicate that the critical current flows predominantly along the surface of the films and that the critical surface currents contribute only very little to the Lorentz force on a fluxoid.

  14. Practical superconductor development for electrical power applications: Quarterly report for the period ending December 31, 1999

    International Nuclear Information System (INIS)

    2000-01-01

    This is a multiyear experimental research program focused on improving relevant material properties of high-T c superconductors (HTSS) and on development of fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne (ANL) program. Recent results on substrate deposition for coated conductors, vortex studies, development of hardened Ag-alloy sheaths for powder-in-tube conductors, and sol-gel processing of NdBa 2 Cu 3 O x (Nd-123) are presented

  15. Practical superconductor development for electrical power applications. Quarterly report for the period ending March 31, 2000

    International Nuclear Information System (INIS)

    2000-01-01

    This is a multiyear experimental research program focused on improving relevant material properties of high-T c superconductors (HTSs) and on development of fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne program. Recent results are presented on YBa 2 Cu 3 O x (Y-123) coated conductors, sheathed (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O x (Bi-2223) tapes, and applications development

  16. A Novel Method for Measurements of the Penetration Depth of MgB2 Superconductor Films by Using Sapphire Resonators with Short-Circuited Parallel Plates

    International Nuclear Information System (INIS)

    Jung, Ho Sang; Lee, J. H.; Cho, Y. H.; Lee, Sang Young; Seong, W. K.; Lee, N. H.; Kang, W. N.

    2009-01-01

    We introduce a measurement method that enables to measure the penetration depth(λ) of superconductor films by using a short-ended parallel plate sapphire resonator. Variations in the (λof MgB 2 films could be measured down to the lowest temperature using a sapphire resonator with a YBa 2 Cu 3 O 7-x film at the bottom. A model equation of λλ 0 [1-(T/T c ) τ ] -1/2 for MgB 2 films appeared to describe the observed variations of the resonant frequency of the sapphire resonator with temperature, with λ 0 , τ and T c used as the fitting parameters.

  17. Possibilities of development photodynamic therapy under high temperature superconductor magnetic field

    International Nuclear Information System (INIS)

    Sen, Mihir

    1996-01-01

    After a long extensive research work neutron photon therapy for treatment of acquired immuno-deficiency syndrome (AIDS) was developed. High temperature superconductor magnet was developed and fitted in magnetic resonance imaging system to guide the patient. By this neutron-photon therapy AIDS effected cells are identified prominently. Patient is then injected with light sensitive drug molecules, which only AIDS cell retain. Light from photon (laser) then energizes the drug, which passes that energy to oxygen, which then leads a biochemical attack on the AIDS cells. If all goes well, the AIDS affected cells die. 10 refs., 1 fig

  18. Heteroepitaxial growth of strained multilayer thin films of high-temperature superconductors

    International Nuclear Information System (INIS)

    Gross, R.; Gupta, A.; Olsson, E.; Segmueller, A.; Koren, G.

    1991-01-01

    Recently, the heteroepitaxial growth of multilayer structures of different copper oxide superconductors has been reported by several groups. In general, two different types of multilayer structures should be distinguished. The first kind of mulitlayer is formed by high-T c materials having the same crystal structure and almost the same lattice constants, as for example ReBa 2 Cu 3 O 7 (Re=rare earth) multilayers with alternating Re-elements. In these multilayers the two different rare earth copper oxides (Y/Dy, Y/Pr) have the same orthorhombic unit cell. Due to the very similar lattice constants, the misfit strain is easily accommodated without the formation of defects. The second kind of multilayer is formed by layers of materials having different crystal structure and lattice parameters. In these multilayers the misfit can be coherently accommodated below a critical modulation thickness as discussed below. This renders possible the heteroepitaxial growth of strained multilayer structures, both of two copper oxides of different crystal structure, as has been demonstrated recently for the system YBa 2 Cu 3 O 7-δ /Nd 1.83 Ce 0.17 CuO x , and of superconducting copper oxides and insulating materials. For multilayers of different copper oxides, a combination of almost all high-Tc materials should be possible, since the presence of the CuO 2 sheets in these materials results in similar lattice constants in their basal planes ('a' and 'b'). (orig./BHO)

  19. High transition temperature superconductor/insulator bilayers for the development of ultra-fast electronics

    International Nuclear Information System (INIS)

    Sirena, M.; Félix, L. Avilés; Haberkorn, N.

    2013-01-01

    High transition temperature superconductor (HTc)/SrTiO 3 (STO) bilayers were fabricated by sputtering deposition on (100) STO substrates. Their transport and morphological properties were characterized using conductive atomic force microscopy. The STO barriers present good insulating properties, with long attenuation lengths (λ ∼ 1 nm) which reduce the junction resistance and increase the operating critical current. The samples present roughness values smaller than 1 nm, with an extremely low density of surface defects (∼5 × 10 −5 defects/μm 2 ). The high control of the barrier quality over large defect free surfaces is encouraging for the development of microelectronics devices based in HTc Josephson junctions

  20. Resputtering-induced chemical inhomogeneity during the growth of high Tc superconductor thin films

    International Nuclear Information System (INIS)

    Ismat Shah, S.

    1991-01-01

    High T c films belonging to Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems have been fabricated by reactive sputtering of single targets in a planar magnetron and Ar+O 2 sputtering atmosphere. Although it was possible to deposit films of correct composition, resputtering related composition variation was a problem. The key to obtaining correct chemistry was a proper control of the deposition parameters. The pressure and oxygen content of the sputtering gas were found to be the most critical parameters. Results of the variation of these parameters on the cation chemistry are presented in this paper. Results from Monte-Carlo simulation of the sputtering process are also presented showing that low pressure and oxygen content of the sputtering gas result in a higher yield of energetic reflected neutrals which can cause compositional variation in the film mainly due to preferential sputtering of the growing film. The effect was particularly noticeable directly underneath the target. The energetic particle bombardment can be controlled by using moderately high pressures and low oxygen concentration in the gas. (author). 11 refs., 7 figs

  1. On the principles of vortex localization and motion in superconductor thin films with artifically patterned cavities

    Czech Academy of Sciences Publication Activity Database

    Yurchenko, Vitaliy; Jirsa, Miloš; Stupakov, Oleksandr; Wördenweber, R.

    2005-01-01

    Roč. 139, 1/2 (2005), s. 331-338 ISSN 0022-2291. [NATO Advanced Research Workshop. Yalta Crimea , 13.09.2004-17.09.2004] Institutional research plan: CEZ:AV0Z1010914 Keywords : superconducting thin films * antidots * vortex dynamics * vortex pinning * relaxation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.753, year: 2005

  2. Chiral superconductors.

    Science.gov (United States)

    Kallin, Catherine; Berlinsky, John

    2016-05-01

    Chiral superconductivity is a striking quantum phenomenon in which an unconventional superconductor spontaneously develops an angular momentum and lowers its free energy by eliminating nodes in the gap. It is a topologically non-trivial state and, as such, exhibits distinctive topological modes at surfaces and defects. In this paper we discuss the current theory and experimental results on chiral superconductors, focusing on two of the best-studied systems, Sr2RuO4, which is thought to be a chiral triplet p-wave superconductor, and UPt3, which has two low-temperature superconducting phases (in zero magnetic field), the lower of which is believed to be chiral triplet f-wave. Other systems that may exhibit chiral superconductivity are also discussed. Key signatures of chiral superconductivity are surface currents and chiral Majorana modes, Majorana states in vortex cores, and the possibility of half-flux quantum vortices in the case of triplet pairing. Experimental evidence for chiral superconductivity from μSR, NMR, strain, polar Kerr effect and Josephson tunneling experiments are discussed.

  3. Development of superconductor electronics technology for high-end computing

    Energy Technology Data Exchange (ETDEWEB)

    Silver, A [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Kleinsasser, A [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Kerber, G [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States); Herr, Q [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States); Dorojevets, M [Department of Electrical and Computer Engineering, SUNY-Stony Brook, NY 11794-2350 (United States); Bunyk, P [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States); Abelson, L [Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 (United States)

    2003-12-01

    This paper describes our programme to develop and demonstrate ultra-high performance single flux quantum (SFQ) VLSI technology that will enable superconducting digital processors for petaFLOPS-scale computing. In the hybrid technology, multi-threaded architecture, the computational engine to power a petaFLOPS machine at affordable power will consist of 4096 SFQ multi-chip processors, with 50 to 100 GHz clock frequency and associated cryogenic RAM. We present the superconducting technology requirements, progress to date and our plan to meet these requirements. We improved SFQ Nb VLSI by two generations, to a 8 kA cm{sup -2}, 1.25 {mu}m junction process, incorporated new CAD tools into our methodology, demonstrated methods for recycling the bias current and data communication at speeds up to 60 Gb s{sup -1}, both on and between chips through passive transmission lines. FLUX-1 is the most ambitious project implemented in SFQ technology to date, a prototype general-purpose 8 bit microprocessor chip. We are testing the FLUX-1 chip (5K gates, 20 GHz clock) and designing a 32 bit floating-point SFQ multiplier with vector-register memory. We report correct operation of the complete stripline-connected gate library with large bias margins, as well as several larger functional units used in FLUX-1. The next stage will be an SFQ multi-processor machine. Important challenges include further reducing chip supply current and on-chip power dissipation, developing at least 64 kbit, sub-nanosecond cryogenic RAM chips, developing thermally and electrically efficient high data rate cryogenic-to-ambient input/output technology and improving Nb VLSI to increase gate density.

  4. Development of superconductor electronics technology for high-end computing

    International Nuclear Information System (INIS)

    Silver, A; Kleinsasser, A; Kerber, G; Herr, Q; Dorojevets, M; Bunyk, P; Abelson, L

    2003-01-01

    This paper describes our programme to develop and demonstrate ultra-high performance single flux quantum (SFQ) VLSI technology that will enable superconducting digital processors for petaFLOPS-scale computing. In the hybrid technology, multi-threaded architecture, the computational engine to power a petaFLOPS machine at affordable power will consist of 4096 SFQ multi-chip processors, with 50 to 100 GHz clock frequency and associated cryogenic RAM. We present the superconducting technology requirements, progress to date and our plan to meet these requirements. We improved SFQ Nb VLSI by two generations, to a 8 kA cm -2 , 1.25 μm junction process, incorporated new CAD tools into our methodology, demonstrated methods for recycling the bias current and data communication at speeds up to 60 Gb s -1 , both on and between chips through passive transmission lines. FLUX-1 is the most ambitious project implemented in SFQ technology to date, a prototype general-purpose 8 bit microprocessor chip. We are testing the FLUX-1 chip (5K gates, 20 GHz clock) and designing a 32 bit floating-point SFQ multiplier with vector-register memory. We report correct operation of the complete stripline-connected gate library with large bias margins, as well as several larger functional units used in FLUX-1. The next stage will be an SFQ multi-processor machine. Important challenges include further reducing chip supply current and on-chip power dissipation, developing at least 64 kbit, sub-nanosecond cryogenic RAM chips, developing thermally and electrically efficient high data rate cryogenic-to-ambient input/output technology and improving Nb VLSI to increase gate density

  5. Superconductors at the nanoscale. From basic research to applications

    Energy Technology Data Exchange (ETDEWEB)

    Woerdenweber, Roger [Forschungszentrum Juelich GmbH (Germany). Peter Gruenberg Inst.; Moshchalkov, Victor [KU Leuven (Belgium). Inst. for Nanoscale Physics and Chemistry; Bending, Simon [Bath Univ. (United Kingdom). School of Physics; Tafuri, Francesco (ed.) [Seconda Univ. di Napoli, Aversa (Italy)

    2017-07-01

    By covering theory, design, and fabrication of nanostructured superconducting materials, this monograph is an invaluable resource for research and development. This book contains the following chapters: Tutorial on nanostructured superconductors; Imaging vortices in superconductors: from the atomic scale to macroscopic distances; Probing vortex dynamics on a single vortex level by scanning ac-susceptibility microscopy; STM studies of vortex cores in strongly confined nanoscale superconductors; Type-1.5 superconductivity; Direct visualization of vortex patterns in superconductors with competing vortex-vortex interactions; Vortex dynamics in nanofabricated chemical solution deposition high-temperature superconducting films; Artificial pinning sites and their applications; Vortices at microwave frequencies; Physics and operation of superconducting single-photon devices; Josephson and charging effect in mesoscopic superconducting devices; NanoSQUIDs: Basics and recent advances; Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} intrinsic Josephson junction stacks as emitters of terahertz radiation; Interference phenomena in superconductor-ferromagnet hybrids; Spin-orbit interactions, spin currents, and magnetization dynamics in superconductor/ferromagnet hybrids; Superconductor/ferromagnet hybrids.

  6. Raman scattering study of phonons in Bi-based superconductor thin films

    International Nuclear Information System (INIS)

    Mejia-Garcia, C.; Diaz-Valdes, E.; Contreras-Puente, G.; Lopez-Lopez, J.L.; Jergel, M.; Morales, A.

    2004-01-01

    Raman spectra were obtained from samples of Bi-Pb-Sr-Ca-Cu-O (BPSCCO) thin films after varying several growth parameters, such as covering material, annealing time (t R ), annealing temperature (T R ), and nominal lead content (x). Thin films with the nominal composition Bi 1.4 Pb x Sr 2 Ca 2 Cu 3 O δ were grown on MgO substrates by a spray pyrolysis technique, followed by a solid state reaction. The results of Raman scattering measurements at room temperature show a series of vibrational optical modes within the range 300-900 cm -1 . The assignment of these modes was made by involving mainly the 2212 and 2223 phases and was confirmed by both X-ray diffraction and resistance in dependence of the temperature (R-T) measurements as well

  7. High-energy helium backscattering for the compositional analysis of thin-film oxide-superconductors

    International Nuclear Information System (INIS)

    Hubbard, K.M.; Martin, J.A.; Muenchausen, R.E.; Tesmer, J.R.; Nastasi, M.

    1989-01-01

    Recent experiments have demonstrated that the broad elastic-scattering resonance for 8.8 MeV helium bombardment of oxygen can be exploited to measure the oxygen content of YBaCuO thin films. A potential difficulty with such measurements is distortion of the backscattering spectrum due to resonant scattering from the substrate elements, which could prevent the accurate integration of peak areas. We have measured the elastic scattering cross sections for Sr and Ti, relative to Gd, with He ions in the energy range of 2.2--8.8 MeV, and a scattering angle of 166 degree. The results verify that resonant scattering from the substrate does not interfere with the high-energy compositional analysis of YBaCuO films deposited on SrTiO 3 . Scattering cross sections for Ca, measured relative to Ba, have also been determined for application to the analysis of BiSrCaCuO and TlCaBaCuO films. Because of resonant scattering from Ca at beam energies above 6 MeV, two backscattering measurements are required for these materials: one at 8.8 MeV to determine the O content, and one at or below 6 MeV to determine the Ca content. Anticipating a more general applicability of this technique to the analysis of metal-oxide films, data are also presented for a number of elements, as an empirical guideline, which give the beam energies above which scattering cross sections deviate from their Rutherford values, and must be determined experimentally. 10 refs., 6 figs., 4 tabs

  8. Development of (Nb,Ta3Sn multifilamentary superconductor wire for high current applications

    Directory of Open Access Journals (Sweden)

    Durval Rodrigues Jr.

    2000-10-01

    Full Text Available The optimization of the energy generated by a MagnetoHydroDynamic (MHD channel using a superconducting magnet demands the optimization of the magnetic field of the system and of the critical points on the magnet winding. This work must include the development of a high performance superconductor wire suitable for this system. Aiming to the construction of improved performance MHD channel, it was developed a low cost superconductor wire, with the required characteristics. The wire was made using a technology compatible with the assembling steps and heat treatment conditions of the MHD superconducting magnets fabrication. It was used the internal Sn method in Nb-7.5wt%Ta tube to fabricate a 271-filament wire with a diameter of 0.81 mm and a Cu/nonCu ratio of 2.3. The wire was heat treated at 200 °C to diffuse the Sn into the Cu shell, producing bronze, followed by the final reaction at temperatures ranging from 670 °C to 730 °C during 25 to 150 h, to produce (Nb,Ta3Sn. The superconducting wire characterization was made measuring the critical current Ic versus the applied magnetic field in the range of 5 to 20 T, the critical temperature Tc and the residual resistivity ratio (RRR. The wire transported critical currents above those available in commercial superconducting wires. These values of Ic are higher than the expected values for the optimization of the MHD channel.

  9. Temperature dependence of the optical conductivity and penetration depth in superconductor MgB2 film

    International Nuclear Information System (INIS)

    Moarrefi, M.; Yavari, H.; Elahi, M.

    2010-01-01

    By using Green's function method the temperature dependence of the optical conductivity and penetration depth of high-quality MgB 2 film are calculated in the framework of the two-band model. We compare our results with experimental data and we argue that the single gap model is insufficient to describe the optical and penetration depth behavior, but the two-band model with different symmetries describes the data rather well. In the two gap model we consider that the both components of optical conductivity are a weighted sum of the contribution from σ and π bonds and hybridization between them is negligible.

  10. Inversion satellites of isolated Perl vortex in thin film of magnetic superconductor

    CERN Document Server

    Lomtev, A I

    2001-01-01

    The electrodynamics equation is derived for the magnetic field of the Perl isolated vortex, moving by the arbitrary law in the ultrafine magnetic conductor and true for every type of the magnetic ordering in the magnetic subsystem. The magnetic structure of the Perl isolated oscillating vortex in the magnetic conductor fine film is studied. It is shown that the oscillations process and the magnetic subsystem essentially renorm the vortex field as compared to the Perl decision. The new events of the inversion satellite (the inversion forerunners in the front of the vortex and the inversion traces behind it) are forecasted, which may be actually observed in the magnetic optical experiments

  11. The superconductor

    International Nuclear Information System (INIS)

    Lad, J.K.

    1979-01-01

    Techniques for fabrication of a few important superconductors like Nb, Ti and Nb 3 Sn are described. Copper or bronze or both can be used as a matrix in the superconductor. Current densities obtained for different ratios of copper to superconductor are studied. The specifications of multi-filament Nb 3 Sn superconductors are given. The relative merits of the two superconductors are discussed. The temperature range obtained is approximately 3 0 K and a magnetic field of 9T(tesla) can be achieved. (A.K.)

  12. Electronic transport in the heavy fermion superconductors UPd2Al3 and UNi2Al3. Thin film studies

    International Nuclear Information System (INIS)

    Foerster, Michael

    2008-01-01

    This work addresses the electronical properties of the superconductors UPd 2 Al 3 and UNi 2 Al 3 on the basis of thin film experiments. Epitaxial thin film samples of UPd 2 Al 3 and UNi 2 Al 3 were prepared using UHV Molecular Beam Epitaxy (MBE). For UPd 2 Al 3 , the change of the growth direction from the intrinsic (001) to epitaxial (100) was predicted and sucessfully demonstrated using LaAlO3 substrates cut in (110) direction. With optimized deposition process parameters for UPd 2 Al 3 (100) on LaAlO 3 (110) superconducting samples with critical temperatures up to T c =1.75 K were obtained. UPd 2 Al 3 -AlO x -Ag mesa junctions with superconducting base electrode were prepared and shown to be in the tunneling regime. However, no signatures of a superconducting density of states were observed in the tunneling spectra. The resistive superconducting transition was probed for a possible dependence on the current direction. In contrast to UNi 2 Al 3 , the existence of such feature was excluded in UPd 2 Al 3 (100) thin films. The second focus of this work is the dependence of the resistive transition in UNi 2 Al 3 (100) thin films on the current direction. The experimental fact that the resistive transition occurs at slightly higher temperatures for I parallel a than for I parallel c can be explained within a model of two weakly coupled superconducting bands. Evidence is presented for the key assumption of the two-band model, namely that transport in and out of the ab-plane is generated on different, weakly coupled parts of the Fermi surface. Main indications are the angle dependence of the superconducting transition and the dependence of the upper critical field B c 2 on current and field orientation. Additionally, several possible alternative explanations for the directional splitting of the transition are excluded in this work. An origin due to scattering on crystal defects or impurities is ruled out, likewise a relation to ohmic heating or vortex dynamics. The

  13. Influence of ion-rradiated SrTiO sub 3 on the properties of thin film oxide superconductors. [YBaCuO

    Energy Technology Data Exchange (ETDEWEB)

    Bordes, N; Cohen, M; Nastasi, M; Rollett, A D; Maggiore, C J [Los Alamos National Lab., NM (USA)

    1989-12-10

    The quality of high-temperature superconducting thin films is dependent on the structure of the substrate used. The present work examines the effects of radiation-damaged SrTiO{sub 3} substrates on the properties of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} thin film superconductors. Prior to film deposition, single-crystal SrTiO{sub 3} substrates were cooled to 77 K and irradiated with 400 keV neon ions to doses of 1x10{sup 15} and 1x10{sup 16} ions cm{sup -2}. Following deposition the film/substrate couples were annealed in ''wet'' oxygen at either 850 or 900deg C. Films on substrates irradiated at high doses showed an increase in transition width from 2deg to 8deg and lowered transition temperature from 92 to 65 K relative to films on low dose and unirradiated substrates. These differences are discussed in terms of results obtained from high-energy and Rutherford backscattering and channeling experiments, scanning electron microscopy observations and X-ray diffraction data. (orig.).

  14. Development of software in LabVIEW for measurement of transport properties of high Tc superconductors

    International Nuclear Information System (INIS)

    Reilly, D.; Savvides, N.

    1996-01-01

    Full text: The gathering of data and their analysis are vital processes in experiments. We have used LabVIEW (National Instruments) to develop programs to measure transport properties of high - T c superconductors, eg. resistivity, ac susceptibility, I-V characteristics. Our systems make use of GPIB (IEEE - 488.2) programmable instruments and a personal computer. LabVIEW is a graphical programming system for instrument control and data acquisition, data analysis and presentation. A key feature of LabVIEW is the ability to graphically assemble software modules or virtual instruments (VIs) and 'wire' them together. In this paper we describe the development of several programs and will offer advice to colleagues wanting to explore LabVIEW

  15. Further developments in NbTi superconductors with artificial pinning centers

    International Nuclear Information System (INIS)

    Kanithi, H.C.; Valaris, P.; Motowidlo, L.R.; Zeitlin, B.A.; Scanlan, R.M.

    1992-01-01

    Artificial pinning centers (APC) have been successfully incorporated in multifilamentary NbTi based superconductors. using pure niobium as the pinning material and applying state-of-the-art processing technology, we have developed conductors which exhibit record low-field current densities. Two volume fractions of Nb have been investigated. One of the objectives of the present development effort is the feasibility study of billet scale-up from earlier work. A J 3 (3T) of ∼7500 A/mm 2 , which is twice that of the present MRI conductors, and a J c (5T) of ∼3400 A/mm 2 , have been achieved in samples. The results of this ongoing effort, in terms of conductor configuration, microstructure, critical current density, and pinning force, are presented in this paper. Appropriate comparisons with past performances are made

  16. Development of Textured Buffer Layer on Metal Tapes for Oxide Superconductors

    National Research Council Canada - National Science Library

    Bhattacharya, Rabi

    2002-01-01

    .... UES, in collaboration with Argonne National Laboratory, has developed a multilayer architecture based on in-plane textured MgO film by inclined substrate deposition technique oristatic and moving Hastelloy substrates...

  17. Crossover from negative to positive magnetoresistance in superconductor/ferromagnet composites thick films

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, O. [Centro de Materiales, Facultad de Ingenieria, Universidad de Narino, Ciudad Universitaria Torobajo, Pasto (Colombia); Baca, E. [Grupo de Ingenieria de Nuevos Materiales, Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali (Colombia); Fuchs, D. [Karlsruhe Institute of Technology, Institut fuer Festkoerperphysik, P.O. Box 3640, Karlsruhe (Germany); Moran, O., E-mail: omoranc@unal.edu.c [Laboratorio de Materiales Ceramicos y Vitreos, Departamento de Fisica, Universidad Nacional de Colombia, Sede Medellin, A.A. 568 Medellin (Colombia)

    2010-11-15

    Thick films of ((Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}){sub 0.95}/(LaSr{sub 0.7}Mn{sub 0.3}O{sub 3}){sub 0.05} [(Bi-2223){sub 0.95}(LSMO){sub 0.05}] composites were fabricated on (0 0 1)-oriented LaAlO{sub 3} substrates by a simple melting-quenching-annealing method and their structural, morphological and magnetoelectrical properties carefully studied. Analysis of the X-ray diffraction patterns suggested a highly oriented growth along the c-axis of LSMO. This preferred orientation, with the crystal c-axis being perpendicular to the plane of the substrate, was considered to be indicative of a textured growth mode. Electrical and magnetic measurements showed the presence of ferromagnetism and superconductivity in the composite at temperatures above room temperature and below T{approx}50 K, respectively. A clear crossover from negative to positive magnetoresistance was observed at {approx}80 K in a magnetic field as strong as 5 T.

  18. Fast neutron induced flux pinning in Tl-based high-Tc single crystals and thin films, highly textured tapes and melt-textured bulk 123-superconductors

    International Nuclear Information System (INIS)

    Brandstaetter, G.; Samadi Hosseinalli, G.; Kern, C.; Sauerzopf, F.M.; Schulz, G.W.; Straif, W.; Yang, X.; Weber, H.W.; Hu, Q.Y.

    1999-01-01

    Various compounds (TI-2223, TI-1223, TI-2212) as well as material forms (single crystals, thin films, ceramics, tapes) of TI-based high temperature superconductors were investigated by magnetic and transport techniques. TI-2223 has a very 'low lying' irreversibility line (H parallel e) and negligible critical current densities J c at 77 K. However, the irreversibility line shifts to higher fields and temperatures and J c is strongly enhanced, even at 77 K, after fast neutron irradiation. In contrast, the related TI-1223 compound has a much steeper irreversibility line (H parallel c) similar to that of Y-123. J c is significant up to 77 K, even in the unirradiated state, and can be largely improved by neutron irradiation. Transport measurements made on TI-1223 tapes still show much lower critical current densities. TI-2212 and Tl-2223 thin films have J c 's at 77 K, which are comparable to those of TI-1223 single crystals. Transport measurements on highly textured Bi-2223 tapes as well as flux profile measurements on Nd-123 bulk superconductors confirm the beneficial effects of neutron induced defects (collision cascades) for flux pinning. (author)

  19. High transition temperature superconductor/insulator bilayers for the development of ultra-fast electronics

    Energy Technology Data Exchange (ETDEWEB)

    Sirena, M.; Félix, L. Avilés [Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Atómico Bariloche, CNEA, Bustillo 9500, 8400 Bariloche (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo and CNEA, 8400 Bariloche (Argentina); Haberkorn, N. [Consejo Nacional de Investigaciones Científicas y Técnicas, Centro Atómico Bariloche, CNEA, Bustillo 9500, 8400 Bariloche (Argentina)

    2013-07-29

    High transition temperature superconductor (HTc)/SrTiO{sub 3} (STO) bilayers were fabricated by sputtering deposition on (100) STO substrates. Their transport and morphological properties were characterized using conductive atomic force microscopy. The STO barriers present good insulating properties, with long attenuation lengths (λ ∼ 1 nm) which reduce the junction resistance and increase the operating critical current. The samples present roughness values smaller than 1 nm, with an extremely low density of surface defects (∼5 × 10{sup −5} defects/μm{sup 2}). The high control of the barrier quality over large defect free surfaces is encouraging for the development of microelectronics devices based in HTc Josephson junctions.

  20. Development of a generic seed crystal for the fabrication of large grain (RE)-Ba-Cu-O bulk superconductors

    International Nuclear Information System (INIS)

    Shi, Y; Babu, N Hari; Cardwell, D A

    2005-01-01

    The critical current density, J c , irreversibility field, B irr , and magnetic field trapping ability of (LRE)-Ba-Cu-O bulk superconductors, where LRE is a light rare earth element such as Nd, Sm, Eu and Gd, are generally superior to those of the more common melt-processed Y-Ba-Cu-O (YBCO). The lack of availability of a suitable seed crystal to grow large, single grain (LRE)-Ba-Cu-O superconductors with controlled orientation, however, has hindered severely the development of these materials for engineering applications over the past ten years. In this communication we report for the first time the development of a generic seed crystal that can be used to fabricate any rare earth (RE) based (RE)-Ba-Cu-O ((RE)BCO) superconductor in the form of a large single grain with controlled orientation. The new seed crystal will potentially enable large grain (LRE)-Ba-Cu-O bulk superconductors to be fabricated routinely, as is the case for YBCO. This will enable the field trapping and current-carrying characteristics of these materials to be explored in more detail than has been possible to date. (rapid communication)

  1. Survey of potential electronic applications of high temperature superconductors

    International Nuclear Information System (INIS)

    Hammond, R.B.; Bourne, L.C.

    1991-01-01

    In this paper the authors present a survey of the potential electronic applications of high temperature superconductor (HTSC) thin films. During the past four years there has been substantial speculation on this topic. The authors will cover only a small fraction of the potential electronic applications that have been identified. Their treatment is influenced by the developments over the past few years in materials and device development and in market analysis. They present their view of the most promising potential applications. Superconductors have two important properties that make them attractive for electronic applications. These are (a) low surface resistance at high frequencies, and (b) the Josephson effect

  2. Test for the presence of long-ranged Coulomb interactions in thin TiN films near the superconductor-insulator transition

    Energy Technology Data Exchange (ETDEWEB)

    Kronfeldner, Klaus; Strunk, Christoph [Institute for Experimental and Applied Physics, University of Regensburg (Germany); Baturina, Tatyana [A.V. Rzhanov Institute of Semiconductor Physics, SB RAS (Russian Federation)

    2016-07-01

    We have measured the conductance of square shaped TiN films on the superconducting and the insulating side of the superconductor/insulator transition. The conductance shows thermally activated behaviour with an activation energy k{sub B}T{sub 0}(L) ∝ lnL, with L being the lateral size of the squares. Such behavior is consistent with 2D long-ranged Coulomb interactions with a large electrostatic screening length Λ ≅ 200 μm. To independently test whether long ranged Coulomb interactions can be responsible for the observed size dependence we compare R(T,B) of a large TiN film in the critical region with and without a screening Pd layer in a distance t ∼ 60 nm to the TiN film. The screening Pd-layer is expected to reduce the activation energy from ∝ ln [min(L,Λ)] to ∝ ln(t) and the thermally activated resistance in films with L >or similar Λ by the large number Λ/t ≅ 3000. In contrast, our experiment showed no significant reduction of R(T) and T{sub 0}. This suggests that the measured size dependent conductance of our TiN film is not related to long-ranged Coulomb interactions.

  3. Passivation Of High-Temperature Superconductors

    Science.gov (United States)

    Vasquez, Richard P.

    1991-01-01

    Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

  4. Superconductor stability 90: A review

    International Nuclear Information System (INIS)

    Dresner, L.

    1990-01-01

    This paper reviews some recent developments in the field of stability of superconductors. The main topics dealt with are hydrodynamic phenomena in cable-in-conduit superconductors, namely, multiple stability, quench pressure, thermal expulsion, and thermal hydraulic quenchback, traveling normal zones in large, composite conductors, such as those intended for SMES, and the stability of vapor-cooled leads made of high-temperature superconductors. 31 refs., 5 figs

  5. New developments in radiochromic film dosimetry

    International Nuclear Information System (INIS)

    Soares, C. G.

    2006-01-01

    NIST has been a pioneer in the use of radiochromic film for medical dosimetry applications. Beginning in 1988 with experiments with 90 Sr/Y ophthalmic applicators, this work has continued into the present. A review of the latest applications is presented, which include high activity low-energy photon source dosimetry and ultra-high resolution film densitometry for dose enhancement near stents and microbeam radiation therapy dosimetry. An exciting recent development is the availability of a new radiochromic emulsion which has been developed for IMRT dosimetry. This emulsion is an order of magnitude more sensitive than was previously available. Measurements of the sensitivity and uniformity of samples of this new film are reported, using a spectrophotometer and two scanning laser densitometers. A unique feature of the new emulsion is that the peak of the absorbance spectrum falls at the wavelength of the HeNe lasers used in the densitometer, maximising sensitivity. When read at a wavelength of 633 nm, sensitivities on the order of 900 mAU Gy -1 were determined for this new film type, compared with about 40 mAU Gy -1 for type HS film, 20 mAU Gy -1 for type MD-55-2 film, and 3 mAU Gy -1 for type HD-810. Film uniformities were found to be good, on the order of 6% peak to peak. However, there is a strong polarisation effect in the samples examined, requiring care in film orientation during readout. (authors)

  6. Superconductor-normal metal-superconductor process development for the fabrication of small Josephson junctions in ramp type configuration

    International Nuclear Information System (INIS)

    Poepel, R.; Hagedorn, D.; Weimann, T.; Buchholz, F.-I.; Niemeyer, J.

    2000-01-01

    At PTB, a fabrication process has been developed in SNS Nb/PdAu/Nb technology for the verification of small Josephson junctions (JJs) in the deep sub-micron range to enable the implementation of JJs as active elements in highly integrated superconducting circuits. Two steps of this technological development are described with regard to appropriately designed circuit layouts of JJ series arrays (JJAs), the first one in a conventional window type junction (WTJ) configuration and the second one in a ramp type junction (RTJ) configuration. Test circuits of JJAs containing up to 10 000 JJs have been fabricated and experimentally tested. In WTJ configuration, the circuits proved to be sensitive to external perturbing effects affecting the stability of circuit operation. In contrast to that, in RTJ configuration, the circuits realized showed correct function and a high grade of reliability of operation. To produce RTJ circuits, the technology parameters have been set to realize JJs with contact areas of A=0.25μmx1.3μm. At a thickness of the PdAu normal metal layer of d = 40 nm, the values achieved for the critical current density and for the product of critical current and normal state resistance are about j c = 200 k Acm -2 and about I c R N = 21 μV. (author)

  7. Oxide superconductors

    International Nuclear Information System (INIS)

    Cava, R.J.

    2000-01-01

    This article briefly reviews ceramic superconductors from historical and materials perspectives. It describes the factors that distinguish high-temperature cuprate superconductors from most electronic ceramics and places them in the context of other families of superconducting materials. Finally, it describes some of the scientific issues presently being actively pursued in the search for the mechanism for high-temperature superconductivity and the directions of research into new superconducting ceramics in recent years

  8. Macroscopic theory of superconductors

    International Nuclear Information System (INIS)

    Carr, W.J. Jr.

    1981-01-01

    A macroscopic theory for bulk superconductors is developed in the framework of the theory for other magnetic materials, where ''magnetization'' current is separated from ''free'' current on the basis of scale. This contrasts with the usual separation into equilibrium and nonequilibrium currents. In the present approach magnetization, on a large macroscopic scale, results from the vortex current, while the Meissner current and other surface currents are surface contributions to the Maxwell j. The results are important for the development of thermodynamics in type-II superconductors. The advantage of the description developed here is that magnetization becomes a local concept and its associated magnetic field can be given physical meaning

  9. Granularity effect on microwave surface resistance in high-Tc YBa2Cu3O7-x bulk and thin film superconductor

    International Nuclear Information System (INIS)

    Swarup, Ram; Gupta, A.K.

    2001-01-01

    We report the effect of variation of Josephson coupling strength in YBa 2 Cu 3 O 7-x (YBCO) superconductor due to grain enlargement, grain orientation and magnetic field on microwave surface resistance (R s ). The coupling strength in the bulk samples has been increased by increasing the sample density from 4.4 to 5.3 g/cm 3 , whereas in thin films, the same could be increased by increasing the c-axis orientation of the grains. The value of R s (10 GHz, 65 K) in bulk samples has been found to decrease from 52 to 4 mΩ with the increase of the coupling strength from 0.06 to 0.43 and in thin films from 930 to 600 μΩ with increase of the coupling strength from 0.92 to 2.43. The effect of grain decoupling on microwave surface resistance was studied under dc and microwave magnetic fields. The surface resistance increases gradually with the application of dc and microwave magnetic fields due to grain decoupling and finally gets saturated beyond a certain critical field. (author)

  10. Superconductor-ferromagnet-superconductor nanojunctions from perovskite materials

    International Nuclear Information System (INIS)

    Štrbík, V.; Beňačka, Š.; Gaži, Š.; Španková, M.; Šmatko, V.; Knoška, J.; Gál, N.; Chromik, Š.; Sojková, M.; Pisarčík, M.

    2017-01-01

    Highlights: • Superconductor-ferromagnet-superconductor nanojunction. • Nanojunctions prepared by Ga"3"+ focused ion beam patterning. • Indication of triplet Cooper pair component in junction superconducting current. • Qualitative agreement with theoretical model. - Abstract: The lateral superconductor-ferromagnet–superconductor (SFS) nanojunctions based on high critical temperature superconductor YBa_2Cu_3O_x (YBCO) and half-metallic ferromagnet La_0_._6_7Sr_0_._3_3MnO_3 (LSMO) thin films were prepared to investigate a possible presence of long range triplet component (LRTC) of Cooper pairs in the LSMO. We applied Ga"3"+ focused ion beam patterning to create YBCO/LSMO/YBCO lateral type nanojunctions with LSMO length as small as 40 nm. The resistivity vs. temperature, critical current density vs. temperature and resistance vs. magnetic field dependence were studied to recognize the LRTC of Cooper pairs in the LSMO. A non-monotonic temperature dependence of junction critical current density and a decrease of the SFS nanojunction resistance in increased magnetic field were observed. Only weak manifestations of LRTC and some qualitative agreement with theory were found out in SFS nanojunctions realized from the perovskite materials. The presence of equal-spin triplet component of Cooper pairs in half-metallic LSMO ferromagnet is not such apparent as in SFS junctions prepared from low temperature superconductors NbTiN and half-metallic ferromagnet CrO_2.

  11. Superconductor-ferromagnet-superconductor nanojunctions from perovskite materials

    Energy Technology Data Exchange (ETDEWEB)

    Štrbík, V., E-mail: vladimir.strbik@savba.sk [Institute of Electrical Engineering, SAS, Dúbravská Cesta 9, Bratislava (Slovakia); Beňačka, Š.; Gaži, Š.; Španková, M.; Šmatko, V. [Institute of Electrical Engineering, SAS, Dúbravská Cesta 9, Bratislava (Slovakia); Knoška, J. [Center for Free-Electron Laser Science, DESY, Notkestraße 85, 22607, Hamburg (Germany); Department of Physics, University of Hamburg, Luruper Chaussee 149, 22607, Hamburg (Germany); Gál, N.; Chromik, Š.; Sojková, M.; Pisarčík, M. [Institute of Electrical Engineering, SAS, Dúbravská Cesta 9, Bratislava (Slovakia)

    2017-02-15

    Highlights: • Superconductor-ferromagnet-superconductor nanojunction. • Nanojunctions prepared by Ga{sup 3+} focused ion beam patterning. • Indication of triplet Cooper pair component in junction superconducting current. • Qualitative agreement with theoretical model. - Abstract: The lateral superconductor-ferromagnet–superconductor (SFS) nanojunctions based on high critical temperature superconductor YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) and half-metallic ferromagnet La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) thin films were prepared to investigate a possible presence of long range triplet component (LRTC) of Cooper pairs in the LSMO. We applied Ga{sup 3+} focused ion beam patterning to create YBCO/LSMO/YBCO lateral type nanojunctions with LSMO length as small as 40 nm. The resistivity vs. temperature, critical current density vs. temperature and resistance vs. magnetic field dependence were studied to recognize the LRTC of Cooper pairs in the LSMO. A non-monotonic temperature dependence of junction critical current density and a decrease of the SFS nanojunction resistance in increased magnetic field were observed. Only weak manifestations of LRTC and some qualitative agreement with theory were found out in SFS nanojunctions realized from the perovskite materials. The presence of equal-spin triplet component of Cooper pairs in half-metallic LSMO ferromagnet is not such apparent as in SFS junctions prepared from low temperature superconductors NbTiN and half-metallic ferromagnet CrO{sub 2}.

  12. Magnetization curves for thin films of layered type-II superconductors, Kolmogorov-Arnold-Moser theory, and the devil's staircase

    International Nuclear Information System (INIS)

    Burkov, S.E.

    1991-01-01

    Magnetization curves for a thin-layered superconducting film in parallel magnetic field have been shown to become devil's staircases provided the superconducting layers are perpendicular to the film plane. The transition from an incomplete to a complete devil's staircase with decreasing temperature is predicted. A chain of vortices is described by the generalized Frenkel-Kontorova model

  13. Photothermal measurements of superconductors

    International Nuclear Information System (INIS)

    Kino, G.S.; Wu, X.D.; Kapitulnik, A.; Fishman, I.

    1993-01-01

    The authors have developed a new photothermal technique to investigate electronic phase transitions of high temperature superconductors. The phase shift of the thermal wave yields the anisotropic thermal diffusivity coefficient of the sample. The amplitude of the photothermal signal is sensitive to electronic phase transitions of the second kind. The technique is completely noncontacting and nondestructive, and is well suited to measure small and fragile single-crystal high-T c superconductors. The measurements give good agreement with fluctuation theory near the transition temperature. They have studied diffusion in, and superconducting fluctuations of, single crystals of YBa 2 Cu 3 O 7-δ and Bi 2 Sr 2 CaCu 2 O 8 . Both systems show fluctuation effects beyond Gaussian fluctuations. While YBa 2 Cu 3 O 7-δ behaves as a three-dimensional anisotropic superconductor, results on Bi 2 Sr 2 CaCu 2 O 8 indicate strong two-dimensional effects

  14. Development of precipitator of fluid film type

    International Nuclear Information System (INIS)

    Liu Yupu

    1987-01-01

    The precipitator of fluid film type is developed for the determination of fuel element cladding failure of water-cooled reactor. It integrates the scrubber, precipitator and detector. The jet of element cooling water automatically circulates carrier gas and the flow water film transfers precipitates onto the surface of centre electrode. Three different types are designed. On the special test loop, the uranium sample pellets of simulating cladding failure is measured. The sensitivity of precipitators, saturated precipitation voltage, incremental speed of signal, speed of driving out precipitates and the contents of the precipitates are determined. The test shows that the precipitators are highly sensitive, reliable, cheap and easy to operate

  15. An unconventional colour superconductor

    International Nuclear Information System (INIS)

    Huang Mei

    2007-01-01

    Superfluidity, or superconductivity with mismatched Fermi momenta, appears in many systems such as charge-neutral dense quark matter, asymmetric nuclear matter, and in imbalanced cold atomic gases. The mismatch plays the role of breaking the Cooper pairing, and the pair-breaking state cannot be properly described in the framework of standard BCS theory. I give a brief review on recent theoretical developments in understanding unconventional colour superconductivity, including a gapless colour superconductor, chromomagnetic instabilities and the Higgs instability in the gapless phase. I also introduce a possible new framework for describing an unconventional colour superconductor

  16. Achievement report on developing superconductor power applied technologies in fiscal 1999 (1). Research and development of superconductor wire materials, research and development of superconductor power generators, research of total systems, research and development of freezing systems, and verification tests; 1999 nendo chodendo denryoku oyo gijutsu kaihatsu seika hokokusho. 1. Chodendo senzai no kenkyu kaihatsu / chodendo hatsudenki no kenkyu kaihatsu / total system no kenkyu / reito system no kenkyu kaihatsu / jissho shiken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    With an objective to achieve higher efficiency, higher density, and higher stability in power systems, research and development has been performed on superconductor power applied technologies. This paper summarizes the achievements thereof in fiscal 1999. In research and development of the superconductor wire materials, decrease in loss and increase in capacity of the conductors were progressed for the Nb{sub 3}Sn wire material, whereas its mechanical properties and stability were evaluated. In research and development of the superconductor generators, an ultra high speed responding generator was verified of its healthiness in a sudden short circuit test. A linkage test with an operating 77-kV system was performed, wherein verification was given that the superconductor generator can be operated stably against various disturbances. In research and development of the freezing systems, an improved system was structured, which achieved operation of 11,390 hours in a single system as a result of the high reliability of the oil-free structure. In the verification tests, the ultra high speed responding model generator was connect to the freezing system to give such tests as load test, onerous test, actuation test by using the M-G system, and 77-kV system linkage test. The functions, reliability, and durability of the system were verified, and different data were acquired. (NEDO)

  17. Studies of superconductors using a low-temperature, high-field scanning tunneling microscope

    International Nuclear Information System (INIS)

    Kirtley, J.R.; Feenstra, R.M.; Fein, A.P.

    1988-01-01

    We have developed a scanning tunneling microscope (STM) capable of operating at temperatures as low as 0.4 K and fields as high as 8 T. We have used this STM to study the energy gap of the high-T/sub c/ superconductors La--Sr--Cu--O and Y--Ba--Cu--O. We find that the reduced gap for these oxide superconductors falls in the range 3<2Δ/k/sub B/T/sub c/<7, for polycrystalline, single-crystal, and thin-film samples. We have also simultaneously imaged the surface topography and superconducting energy gap for thin films of the granular superconductor NbN. We occasionally see regions with smaller best-fit gaps that correlate with surface topographical features, but have been unable so far to image flux vortices

  18. Making superconductors

    International Nuclear Information System (INIS)

    McDonald, W.K.

    1981-01-01

    A method is described of producing composite rod or wire of increased strength and fineness wherein the composite is formed by reducing a lamina of two metals which have been rolled to form a cylindrical billet in which one of the metals is in expanded form. The composite produced can be encased in copper and fabricated to produce a superconductor. Alloys contemplated for producing superconductors are Nb 3 Sn, Nb 3 Ga, Nb 3 Ge, Nb 3 Si, Nb-Ti, V 3 Ga, V 3 Si, V 3 Sn, V 3 Al, and V 3 Ge laminated on bronze, Al, Cu, Ta, or combinations thereof. (author)

  19. Development of MgB2 superconductor wire with high critical current

    International Nuclear Information System (INIS)

    Kim, Chan Joong; Jun, Byung Hyuk; Park, Soon Dong; Kim, Nam Kyu; Kim, Yi Jeong; Yi, Ji Hye; Lee, Ji Hyun; Tan, Kai Sin

    2009-07-01

    The MgB 2 superconductor with smaller grain size could improve its critical properties by providing flux pinning centers with high grain boundary density. The effects of C doping such as charcoal, paper ash and glycerin on the superconducting properties was investigated for in situ processed MgB 2 samples using low purity semi-crystalline B powder. The results show a decrease in Tc and an enhancement of Jc at high fields for the C-doped samples as compared to the un-doped samples. A combined process of a mechanical ball milling and liquid glycerin (C 3 H 8 O 3 ) treatment of B powder has been conducted to enhance the superconducting properties of MgB 2 . The mechanical ball milling was effective for grain refinement, and a lattice disorder was easily achieved by glycerin addition. With the combined process, the critical properties was further increased due to a higher grain boundary density and a greater C substitution. To get fine grain structure of MgB 2 with high critical current properties, mechanical milling for as-received B powder and low temperature solid-state reaction of 550 or 600 .deg. C were attempted to in situ powder-in-tube processed MgB 2 /Fe wires. The critical current properties of the MgB 2 wires using the milled B powder were enhanced due to a smaller grain size and an increased volume of the superconducting phase. The solid-state reaction of a low temperature process for the samples using the milled B powder resulted in a poorer crystallinity with a smaller grain size, which improved superconducting properties. We established the system to measure the transport current properties of the MgB 2 wires. The field dependence of the transport Jc was evaluated for the MgB 2 wires heat-treated at different heat treatment conditions using ball-milled and glycerin-treated B powder. The MgB 2 magnet was developed and the AC loss of MgB 2 wire was also investigated. A conduction cooling device to cool the MgB 2 coil down to 4 K has been fabricated and the

  20. Superconductors and medical imaging

    International Nuclear Information System (INIS)

    Aubert, Guy

    2011-01-01

    After difficult beginnings in the 1970's, magnetic resonance imaging (MRI) has evolved to become nowadays the jewel in the crown of medical technology. Superconductors have been a key factor for the extraordinary expansion of MRI which in turn represents about 75 % of their total market. After recalling some basic principles, this article traces their common history and refers to future developments. (author)

  1. Inhomogeneous superconductors

    International Nuclear Information System (INIS)

    Tinkham, M.

    1978-01-01

    The coherence length xi and penetration depth lambda set the characteristic length scales in superconductors, typically 100 to 5,000 A. A lattice of flux lines, each carrying a single quantum, can penetrate type II superconductors, i.e., those for which kappa identical with lambda/xi > 1/√2. Inhomogeneities on the scale of the flux lattice spacing are required to pin the lattice to prevent dissipative flux motion. Recent work using voids as pinning centers has demonstrated this principle, but practical materials rely on cold-work, inclusions of second phases, etc., to provide the inhomogeneity. For stability against thermal fluctuations, the superconductor should have the form of many filaments of diameter 10 to 100 μm imbedded in a highly conductive normal metal matrix. Such wire is made by drawing down billets of copper containing rods of the superconductor. An alternative approach is the metallurgical one of Tsuei, which leads to thousands of superconducting filamentary segments in a copper matrix. The superconducting proximity effect causes the whole material to superconduct at low current densities. At high current densities, the range of the proximity effect is reduced so that the effective superconducting volume fraction falls below the percolation threshold, and a finite resistance arises from the copper matrix. But, because of the extremely elongated filaments, this resistance is orders of magnitude lower than that of the normal wire, and low enough to permit the possibility of technical applications

  2. Kinetic equations in dirty superconductors

    International Nuclear Information System (INIS)

    Kraehenbuehl, Y.

    1981-01-01

    Kinetic equations for superconductors in the dirty limit are derived using a method developed for superfluid systems, which allows a systematic expansion in small parameters; exact charge conservation is obeyed. (orig.)

  3. Development of the reactor safety film

    International Nuclear Information System (INIS)

    Sheheen, N.N.; Hodson, P.J.

    1981-01-01

    The first computer-generated film of LASL's Reactor Safety efforts was developed using the ANIMATE framework, a program that adds visual capabilities to MAPPER. Numerous software limitations had to be overcome within a very limited production schedule. A significant achievement was the 15,000-vector-per-frame sequence depicting a pressurized water reactor core with parts flashing while pumps circulate fluid through the system

  4. Development of Y-Ba-Cu-O Superconductors for Magnetic Bearings

    Science.gov (United States)

    Selvamanickam, V.; Pfaffenbach, K.; Sokolowski, R. S.; Zhang, Y.; Salama, K.

    1996-01-01

    The material requirements, material manufacturing and magnetic properties that are relevant to fabrication of High Temperature Superconductor (HTS) magnetic bearings have been discussed. It is found that the seeded-melt-texturing method can be used to fabricate the single domain material that is required to achieve the best magnetic properties. Trapped-field mapping has been used as a non-destructive tool to determine the single-domain nature of the HTS material and quantity of the HTS disks. Both the trapped field and the levitation force of the Y-Ba-Cu-O disks are found to be strongly sensitive to the oxygen content.

  5. Microwave plasma CVD of oxide films relating to high Tc Bi-Sr-Ca-Cu-O superconductor

    International Nuclear Information System (INIS)

    Hashimoto, T.; Kosaka, T.; Yoshida, Y.; Yoshimoto, M.; Koinuma, H.

    1989-01-01

    Microwave plasma CVD was applied to the synthesis of Bi, Sr, Ca, and Cu oxide films at relatively low temperatures. Gas source materials used were Bi(C 6 H 5 ) 3 , Sr(PPM) 2 , Ca(PPM) 2 , and Cu(HFA) 2 , where PPM and HFA represent C 2 F 5 COCHCOC(CH 3 ) 3 and CF 3 COCHCOCF 3 , respectively. Films were deposited on MgO (100) substrate at temperatures between 200 C and 400 C under an atmosphere of 1000mTorr Ar-O 2 (50/100) mixture which was partially excited by plasma. From Bi(C 6 H 5 ) 3 , Bi 2 O 3 was formed at 200 C without containing carbon above the detection level by XPS analysis. From Cu(HFA) 2 , CuO was prepared at 400 C by increasing oxygen partial pressure to 0.1Torr. (At lower oxygen partial pressure, CuF 2 or amorphous films were deposited.) From Sr(PPM) 2 and Ca(PPM) 2 , SrF 2 and CaF 2 were obtained at 400 C. The attempt to fabricate superconducting films is also reported

  6. Chapter 27. Superconductors

    International Nuclear Information System (INIS)

    Vavra, O.

    2007-01-01

    In this chapter author deals with superconductors and superconductivity. Different chemical materials used as high-temperature superconductors are presented. Some applications of superconductivity are presented.

  7. Report on achievements in fiscal 1999 of New Sunshine Project. Development of superconductor power applied technologies. Research on total system; 1999 nendo chodendo denryoku oyo gijutsu kaihatsu gyomu seika hokokusho. Total system nado no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    To deal effectively with problems being actualized in electric power systems, it is necessary to introduce superconductor technologies into power devices, and achieve higher efficiency, density and stability in the power systems. To achieve the goal, development is being made on superconductor power applied technologies, whereas investigative researches are given on the effects of introducing the superconductor power applied devices to proceed the development effectively and smoothly. This project is also given evaluations on its research achievements. In the practical application of superconductor generators, all of the verification tests have been completed, with the model generator system linkage test as the final test. Design and fabrication technologies were established on a 200,000-kW class pilot generator after having gone through analyses made after the tests. Not only having achieved the initial technical value targets, the result presented reliability required for practical use of the superconductor generator, having exceeded the expectation. The research and development of the superconductor generator technologies under this project is concluded successful. The AC superconductor devices were developed by effectively utilizing the results of the leading researches on fundamental technologies for AC superconductor power device technologies as well as other results of the world's highest levels. (NEDO)

  8. Development of superconductor application technology - Flywheel energy storage system using superconducting magnetic bearing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Hun; Oh, Hueng Kuk; Yun, Keyng Reyl; Lee, Jeung Kun [Ahju University, Suwon (Korea, Republic of)

    1996-06-01

    Electricity must be used simultaneously with its generation. Existing storage methods either are dependent on special geography, are too expensive,= or are too inefficient. Electricity demand changes by as much as 30% over a 12-hour period and result in significant costs for utilities as power output get adjusted to meet these changes. The purpose of HTS FES is to store unused nighttime electricity until it is needed during the daytime. If every element of a rotating flywheel is stressed to a prescribed allowable value, the flywheel material will clearly be used in most efficient manner. The uniformlt stressed flywheel is about 25% stronger than a flat disk. The gap between superconductor and permanent magnet was 1.85 mm, and using bearing connector with the values, joining superconductor to permanent magnet Using bolt connector, joining permanent magnet to flywheel. Joined system is excited by exciting function that magnitude is 1, range is 0 up to 4000 HZ. 3 rd and 4 th natural frequency, 1857 HZ and 2340 HZ, in X direction and 2 nd natural frequency, 28.57 HZ, are avoided to prevent resonance. 15 refs., 11 tabs., 53 figs. (author)

  9. Development of Nb3Sn based multi-filamentary superconductor wires for fusion reactor magnets

    International Nuclear Information System (INIS)

    Kundu, Sayandeep; Singh, A.K.; Hussain, M.M.

    2016-01-01

    Nb 3 Sn is a proposed type II superconductor material to be used as superconducting magnet in fusion reactor for its superior superconducting properties. Fabrication of long single length wire containing Nb 3 Sn filaments is a challenge. The usual manufacturing philosophy involves deforming an assembly of tin and niobium in copper matrix to the final size, followed by the heat treatment to produce superconducting phase at Nb-Cu interface. Multi-filamentary wires were fabricated by hot extrusion of superconductor billet followed by several stages of cold drawing. Heat treatments at various temperature and time were carried out on as formed wire containing multiple filaments in order to see the growth of superconducting intermetallic phase during subsequent characterization. Post heat treatment characterization through SEM, EBSD and EDS revealed the presence of intermetallic phase of Nb and Sn, hypo stoichiometric in Sn, at the Cu-Nb interface growing towards the center of Nb filament. The manufacturing process till the desired final size of the wire happened to be a challenge, mainly because it required extraordinary co-deformability between various materials in such an assembly. Post-trial failure analysis through destructive testing using optical and scanning electron micrographs revealed the propensity of internal radial cracks at Cu-Sn interfaces, while the Nb-Cu interfaces were found to be relatively unaffected. This paper will discuss the details of the fabrication process. (author)

  10. Ternary superconductors

    International Nuclear Information System (INIS)

    Giorgi, A.L.

    1987-01-01

    Ternary superconductors constitute a class of superconducting compounds with exceptional properties such as high transition temperatures (≅ 15.2 K), extremely high critical fields (H c2 >60 Tesla), and the coexistence of superconductivity and long-range magnetic order. This has generated great interest in the scientific community and resulted in a large number of experimental and theoretical investigations in which many new ternary compounds have been discovered. A review of some of the properties of these ternary compounds is presented with particular emphasis on the ternary molybdenum chalcogenides and the ternary rare earth transition metal tetraborides. The effect of partial substitution of a second metal atom to form pseudoternary compounds is examined as well as some of the proposed correlations between the superconducting transition temperature and the structural and electronic properties of the ternary superconductors

  11. Superconductor Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gömöry, F [Bratislava, Inst. Elect. Eng. (Slovakia)

    2014-07-01

    Superconductors used in magnet technology could carry extreme currents because of their ability to keep the magnetic flux motionless. The dynamics of the magnetic flux interaction with superconductors is controlled by this property. The cases of electrical transport in a round wire and the magnetization of wires of various shapes (circular, elliptical, plate) in an external magnetic field are analysed. Resistance to the magnetic field penetration means that the field produced by the superconducting magnet is no longer proportional to the supplied current. It also leads to a dissipation of electromagnetic energy. In conductors with unequal transverse dimensions, such as flat cables, the orientation with respect to the magnetic field plays an essential role. A reduction of magnetization currents can be achieved by splitting the core of a superconducting wire into fine filaments; however, new kinds of electrical currents that couple the filaments consequently appear. Basic formulas allowing qualitative analyses of various flux dynamic cases are presented.

  12. THE DEVELOPMENT OF THE MECHANICS OF FILM RATING.

    Science.gov (United States)

    HANDY, RICKI; AND OTHERS

    A TRANSCRIPTION WAS MADE OF A GROUP DISCUSSION DEALING WITH THE DEVELOPMENT OF RATING SCALES AND THE TECHNIQUES OF FILM RATING AND OF USE OF THE EQUIPMENT. THE AMIDON-FLANDERS INTERACTION ANALYSIS SCALE WAS USED AS THE BASIS FOR THE DEVELOPMENT OF THE FILM ANALYSIS OF INTERACTION RECORD (FAIR). DISCUSSIONS DEALT WITH SUCH PROBLEMS OF FILM RATING…

  13. Epitaxial growth of high temperature superconductors by cathodic sputtering I: thin films of YBaCuO

    International Nuclear Information System (INIS)

    Navacerrada, M.A.; Sefrioui, Z.; Arias, D.; Varela, M.; Loos, G.; Leon, C.; Lucia, M.L.; Santamaria, J.; Sanchez-Quesada, F.

    1998-01-01

    High quality c-oriented YBa 2 Cu 3 O 7 -x thin films have been grown on SrTiO 3 (100)substrates by high pressure sputtering in pure oxygen atmosphere. Low angle X-ray diffraction and atomic force microscopy were performed on films less than 250 angstrom thick showing a plenitude better than one unit cell. Moreover, the structural characterization by means of X ray φ scans showed that growth is epitaxial. The critical temperature has been measured by different ways and was always in the range 89.5-90.5K. the resistance transition is sharper than 1K and the mutual inductance response always shows magnetic losses peaks narrower than 0.3K. Critical current densities are in excess of 10''''6 angstrom/cm''''2 at 77K. (Author) 8 refs

  14. Role of oxygen partial pressure in microstructural development and properties of YBCO superconductors

    International Nuclear Information System (INIS)

    Singh, J.P.; Guttschow, R.; Dusek, J.T.; Poeppel, R.B.

    1991-01-01

    Results are presented for the effect of oxygen partial pressure (pO 2 ) on the sintered density and microstructure of YBCO superconductors. Extruded YBCO wires were sintered at 910C at different values of pO 2 . Generally, the density increased with decreasing pO 2 , and a density of 91% was achieved at pO 2 = 0.01 atm. Wires sintered at pO 2 = 0.01 atm had a fine microstructure with an average grain size of ∼3 μm and an average strength of 191 MPa. The high strength is due to the small grain size, which causes a decrease in residual tensile stress because of grain anisotropy

  15. X-ray photo-emission studies of Cu1-xTlxBa2Ca3Cu4O12-y superconductor thin films

    International Nuclear Information System (INIS)

    Khan, Nawazish A.; Mumtaz, M.; Ahadian, M.M.; Iraji-zad, Azam

    2006-01-01

    X-ray photo-emission spectroscopy (XPS) studies of Cu 1-x Tl x Ba 2 Ca 3 Cu 4 O 12-y superconductor thin films have been carried out for understanding the mechanism of superconductivity and to find out the reasons for the increase of zero resistivity critical temperature T c (R = 0) with post-annealing in a nitrogen atmosphere. It is observed from these studies that reduction of charge state of thallium is a source of doping of carriers to the CuO 2 planes. The reduced charge state of thallium (i.e. Tl 1+ ) promotes lower oxygen concentration in the charge reservoir layer, which possibly results in movement of electrons to the conducting CuO 2 planes. The higher density of electrons in the CuO 2 planes optimizes the hole concentration 'n p ' in these planes. The reduced charge state of thallium in the Cu 1-x Tl x Ba 2 O 4-δ charge reservoir layer is also supported by a shift of the Ba 3d 5/2 and Ba 3d 3/2 XPS lines to lower binding energies with post-annealing in nitrogen atmosphere. Moreover, the movement of the valance band spectrum to lower binding energies suggested that the electronic density of states changes in the valance band with the post-annealing in nitrogen, which possibly becomes a source of doping of carriers to the CuO 2 planes. The increased doping of electrons to the CuO 2 planes optimizes the Fermi-vector K F and Fermi-velocity V F of the carriers and increases the T c (R = 0) of final compound

  16. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  17. Electronic transport in the heavy fermion superconductors UPd{sub 2}Al{sub 3} and UNi{sub 2}Al{sub 3}. Thin film studies

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Michael

    2008-07-01

    This work addresses the electronical properties of the superconductors UPd{sub 2}Al{sub 3} and UNi{sub 2}Al{sub 3} on the basis of thin film experiments. Epitaxial thin film samples of UPd{sub 2}Al{sub 3} and UNi{sub 2}Al{sub 3} were prepared using UHV Molecular Beam Epitaxy (MBE). For UPd{sub 2}Al{sub 3}, the change of the growth direction from the intrinsic (001) to epitaxial (100) was predicted and sucessfully demonstrated using LaAlO3 substrates cut in (110) direction. With optimized deposition process parameters for UPd{sub 2}Al{sub 3} (100) on LaAlO{sub 3}(110) superconducting samples with critical temperatures up to T{sub c}=1.75 K were obtained. UPd{sub 2}Al{sub 3}-AlO{sub x}-Ag mesa junctions with superconducting base electrode were prepared and shown to be in the tunneling regime. However, no signatures of a superconducting density of states were observed in the tunneling spectra. The resistive superconducting transition was probed for a possible dependence on the current direction. In contrast to UNi{sub 2}Al{sub 3}, the existence of such feature was excluded in UPd{sub 2}Al{sub 3}(100) thin films. The second focus of this work is the dependence of the resistive transition in UNi{sub 2}Al{sub 3}(100) thin films on the current direction. The experimental fact that the resistive transition occurs at slightly higher temperatures for I parallel a than for I parallel c can be explained within a model of two weakly coupled superconducting bands. Evidence is presented for the key assumption of the two-band model, namely that transport in and out of the ab-plane is generated on different, weakly coupled parts of the Fermi surface. Main indications are the angle dependence of the superconducting transition and the dependence of the upper critical field B{sub c{sub 2}} on current and field orientation. Additionally, several possible alternative explanations for the directional splitting of the transition are excluded in this work. An origin due to scattering on

  18. Developing Short Films of Geoscience Research

    Science.gov (United States)

    Shipman, J. S.; Webley, P. W.; Dehn, J.; Harrild, M.; Kienenberger, D.; Salganek, M.

    2015-12-01

    In today's prevalence of social media and networking, video products are becoming increasingly more useful to communicate research quickly and effectively to a diverse audience, including outreach activities as well as within the research community and to funding agencies. Due to the observational nature of geoscience, researchers often take photos and video footage to document fieldwork or to record laboratory experiments. Here we present how researchers can become more effective storytellers by collaborating with filmmakers to produce short documentary films of their research. We will focus on the use of traditional high-definition (HD) camcorders and HD DSLR cameras to record the scientific story while our research topic focuses on the use of remote sensing techniques, specifically thermal infrared imaging that is often used to analyze time varying natural processes such as volcanic hazards. By capturing the story in the thermal infrared wavelength range, in addition to traditional red-green-blue (RGB) color space, the audience is able to experience the world differently. We will develop a short film specifically designed using thermal infrared cameras that illustrates how visual storytellers can use these new tools to capture unique and important aspects of their research, convey their passion for earth systems science, as well as engage and captive the viewer.

  19. Localized superconductors

    International Nuclear Information System (INIS)

    Ma, M.; Lee, P.A.

    1985-01-01

    We study the effects of Anderson localization on superconductivity by using a Bardeen-Cooper-Schrieffer (BCS)-type trial wave function which pairs electrons in exact time-reversed eigenstates of the single-particle Hamiltonian. Within this approximation, and neglecting localization effects on the effective Coulomb repulsion and the electron-phonon coupling, we find that superconductivity persists below the mobility edge. In fact, Anderson's theorem is valid in the localized phase as long as rhoΔ 0 L/sup d/ > 1 (rho is the density of states averaged over +- Δ 0 of the Fermi energy, Δ 0 the BCS gap parameter, and L the localization length). Hence the gap order parameter Δ(r) remains uniform in space at the BCS value Δ 0 . The superfluid density and response to electromagnetic perturbations, however, show marked differences from the ''dirty superconductor'' regime. For rhoΔ 0 L/sup d/ < 1, Δ(r) fluctuates spatially and eventually drops to zero. In the limit when states are site localized, the system crosses over into the ''Anderson negative-U glass.'' Considerations beyond the trial wave-function approximation will speed up the destruction of superconductivity. The superconductor formed from localized states has the property that its quasiparticle excitations are also localized. Such excitations can be probed by observing the normal current in a tunneling junction

  20. Development of neutron diffuse scattering analysis code by thin film and multilayer film

    International Nuclear Information System (INIS)

    Soyama, Kazuhiko

    2004-01-01

    To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering

  1. Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Seino, H; Nagashima, K; Arai, Y [Railway Technical Research Institute, Hikari-cho 2-8-38, Kokubunji-shi, Tokyo (Japan)], E-mail: seino@rtri.or.jp

    2008-02-01

    The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated.

  2. Development of superconducting magnetic bearing using superconducting coil and bulk superconductor

    International Nuclear Information System (INIS)

    Seino, H; Nagashima, K; Arai, Y

    2008-01-01

    The authors conducted a study on superconducting magnetic bearing, which consists of superconducting rotor and stator to apply the flywheel energy-storage system for railways. In this study, high temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. In the first step of the study, the thrust rolling bearing was selected for application by using liquid nitrogen cooled HTS bulk. 60mm-diameter HTS bulks and superconducting coil which generated a high gradient of magnetic field by cusp field were adopted as a rotor and a stator for superconducting magnetic bearing, respectively. The results of the static load test and the rotation test, creep of the electromagnetic forces caused by static flux penetration and AC loss due to eccentric rotation were decreased to the level without any problems in substantial use by using two HTS bulks. In the result of verification of static load capacity, levitation force (thrust load) of 8900N or more was supportable, and stable static load capacity was obtainable when weight of 460kg was levitated

  3. London limit for lattice model of superconductor

    International Nuclear Information System (INIS)

    Ktitorov, S.A.

    2004-01-01

    The phenomenological approach to the strong-bond superconductor, which is based on the Ginzburg-Landau equation in the London limit, is considered. The effect of the crystalline lattice discreteness on the superconductors electromagnetic properties is studied. The classic problems on the critical current and magnetic field penetration are studied within the frames of the lattice model for thin superconducting films. The dependence of the superconducting current on the thin film order parameter is obtained. The critical current dependence on the degree of deviation from the continual approximation is calculated [ru

  4. Theory of disordered superconductors

    International Nuclear Information System (INIS)

    Wysokinski, K.I.

    1991-01-01

    The influence of disorder on the superconducting transition temperature is discussed. The main steps on the way to complete theory of disordered superconductors follows the steps in the authors' understanding of disorder and its effect on the quasiparticles in metals. Loosely speaking one can distinguish three such steps. First is the study of weakly disordered systems and this resulted in famous, celebrated Anderson theorem. The second step is ultimately connected with the coherent potential approximation as a method to study the spectrum and transport in concentrated alloys. The discovery of the role of usually neglected interferences between scattered waves in disordered conductors leading to decrease in mobility and increase of the mutual interactions between quantum particles, known as localization and interaction effects has given the new impetus to the theory of superconductivity. This is third step to be discussed in this lecture. The authors limit themselves to homogeneous bulk superconductors. In this paper some experiments on thin films as well as on copper oxides related to the presented theory are briefly mentioned

  5. Modelling of bulk superconductor magnetization

    International Nuclear Information System (INIS)

    Ainslie, M D; Fujishiro, H

    2015-01-01

    This paper presents a topical review of the current state of the art in modelling the magnetization of bulk superconductors, including both (RE)BCO (where RE = rare earth or Y) and MgB 2 materials. Such modelling is a powerful tool to understand the physical mechanisms of their magnetization, to assist in interpretation of experimental results, and to predict the performance of practical bulk superconductor-based devices, which is particularly important as many superconducting applications head towards the commercialization stage of their development in the coming years. In addition to the analytical and numerical techniques currently used by researchers for modelling such materials, the commonly used practical techniques to magnetize bulk superconductors are summarized with a particular focus on pulsed field magnetization (PFM), which is promising as a compact, mobile and relatively inexpensive magnetizing technique. A number of numerical models developed to analyse the issues related to PFM and optimise the technique are described in detail, including understanding the dynamics of the magnetic flux penetration and the influence of material inhomogeneities, thermal properties, pulse duration, magnitude and shape, and the shape of the magnetization coil(s). The effect of externally applied magnetic fields in different configurations on the attenuation of the trapped field is also discussed. A number of novel and hybrid bulk superconductor structures are described, including improved thermal conductivity structures and ferromagnet–superconductor structures, which have been designed to overcome some of the issues related to bulk superconductors and their magnetization and enhance the intrinsic properties of bulk superconductors acting as trapped field magnets. Finally, the use of hollow bulk cylinders/tubes for shielding is analysed. (topical review)

  6. Development of Anti-Insect Microencapsulated Polypropylene Films Using a Large Scale Film Coating System.

    Science.gov (United States)

    Song, Ah Young; Choi, Ha Young; Lee, Eun Song; Han, Jaejoon; Min, Sea C

    2018-04-01

    Films containing microencapsulated cinnamon oil (CO) were developed using a large-scale production system to protect against the Indian meal moth (Plodia interpunctella). CO at concentrations of 0%, 0.8%, or 1.7% (w/w ink mixture) was microencapsulated with polyvinyl alcohol. The microencapsulated CO emulsion was mixed with ink (47% or 59%, w/w) and thinner (20% or 25%, w/w) and coated on polypropylene (PP) films. The PP film was then laminated with a low-density polyethylene (LDPE) film on the coated side. The film with microencapsulated CO at 1.7% repelled P. interpunctella most effectively. Microencapsulation did not negatively affect insect repelling activity. The release rate of cinnamaldehyde, an active repellent, was lower when CO was microencapsulated than that in the absence of microencapsulation. Thermogravimetric analysis exhibited that microencapsulation prevented the volatilization of CO. The tensile strength, percentage elongation at break, elastic modulus, and water vapor permeability of the films indicated that microencapsulation did not affect the tensile and moisture barrier properties (P > 0.05). The results of this study suggest that effective films for the prevention of Indian meal moth invasion can be produced by the microencapsulation of CO using a large-scale film production system. Low-density polyethylene-laminated polypropylene films printed with ink incorporating microencapsulated cinnamon oil using a large-scale film production system effectively repelled Indian meal moth larvae. Without altering the tensile and moisture barrier properties of the film, microencapsulation resulted in the release of an active repellent for extended periods with a high thermal stability of cinnamon oil, enabling commercial film production at high temperatures. This anti-insect film system may have applications to other food-packaging films that use the same ink-printing platform. © 2018 Institute of Food Technologists®.

  7. Flux pinning enhancements in YBa2Cu3O7-8 superconductors through phase separated, self-assembled LaMnO3-MgO nanocomposite films.

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Ozgur [ORNL; Aytug, Tolga [ORNL; Paranthaman, Mariappan Parans [ORNL; Leonard, Keith J [ORNL; Pennycook, Stephen J [ORNL; Kim, Kyunghoon [ORNL; Cook, Sylvester W [ORNL; Thompson, James R [ORNL; Christen, David K [ORNL; Goyal, Amit [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York; Lupini, Andrew R [ORNL; Meyer, Hendrik [ORNL; Qiu, Xiaofeng [ORNL; Xiong, X. [SuperPower Incorporated, Schenectady, New York

    2011-01-01

    Technological applications of high temperature superconductors (HTS) require high critical current density, Jc, under operation at high magnetic field strengths. This requires effective flux pinning by introducing artificial defects through creative processing. In this work, we generated correlated disorder for strong vortex pinning in the YBa2Cu3O7- (YBCO) films by replacing the standard LaMnO3 (LMO) cap buffer layers in ion beam assisted deposited MgO templates with LMO:MgO composite films. Such films revealed formation of two phase-separated, but at the same time vertically aligned, self-assembled composite nanostructures that extend throughout the entire thickness of the film. Measurements of magnetic-field orientation-dependent Jc of YBCO coatings deposited on these nanostructured cap layers showed correlated c-axis pinning and improved in-field Jc performance compared to those of YBCO films deposited on standard LMO buffers. The present results demonstrate feasibility of novel and potentially practical approaches in the pursuit of more efficient, economical, and high performance superconducting devices.

  8. Future applications of superconductors for industrial use

    International Nuclear Information System (INIS)

    Reddy, S.P.

    1988-01-01

    Superconductors have been in existence for many years. Recent developments in superconductivity at higher temperatures are directed towards the potential use of superconductors at ambient temperatures. The diligent efforts of the scientific, engineering, and political agencies in researching and developing superconducting materials have resulted in encouraging accomplishments. Although superconductors could be used in every branch of electrical engineering, the authors focuses on a few areas in this paper. The power distribution and utilization in a typical industry is compared to that of a system using superconductors. Brief discussions of various machines with superconductors at ambient temperatures, based on developments made so far on large superconducting machines, for potential industrial applications are included in this paper

  9. Development of 3D Slicer based film dosimetry analysis

    International Nuclear Information System (INIS)

    Alexander, K M; Schreiner, L J; Robinson, A; Pinter, C; Fichtinger, G

    2017-01-01

    Radiochromic film dosimetry has been widely adopted in the clinic as it is a convenient option for dose measurement and verification. Film dosimetry analysis is typically performed using expensive commercial software, or custom made scripts in Matlab. However, common clinical film analysis software is not transparent regarding what corrections/optimizations are running behind the scenes. In this work, an extension to the open-source medical imaging platform 3D Slicer was developed and implemented in our centre for film dosimetry analysis. This extension streamlines importing treatment planning system dose and film imaging data, film calibration, registration, and comparison of 2D dose distributions, enabling greater accessibility to film analysis and higher reliability. (paper)

  10. Accelerated color development of irradiated radiochromic dye films

    International Nuclear Information System (INIS)

    Chappas, W.J.

    1981-01-01

    The radiochromic dye films developed by Chalkley and McLaughlin are quickly becoming one of the principal methods for secondary dosimetry. Their useful dose and dose rate ranges, long-term color stability, small and flexible size, and ease of reading make them ideal for spatial dose distribution measurements in the complex targets often encountered in industry. At room temperature, however, their response is slow, requiring several hours after irradiation for full color development. This work examines the effect of humidity on the film's time response and describes a method for accelerating the film's color development. By keeping the film in a controlled humidity environment or through a simple heating technique, the film can be read in minutes instead of hours after irradiation. The results are shown to be identical to those of films stored for 24 hours at room temperature

  11. Physics of thin films advances in research and development

    CERN Document Server

    Hass, Georg; Vossen, John L

    2013-01-01

    Physics of Thin Films: Advances in Research and Development, Volume 12 reviews advances that have been made in research and development concerning the physics of thin films. This volume covers a wide range of preparative approaches, physics phenomena, and applications related to thin films. This book is comprised of four chapters and begins with a discussion on metal coatings and protective layers for front surface mirrors used at various angles of incidence from the ultraviolet to the far infrared. Thin-film materials and deposition conditions suitable for minimizing reflectance changes with

  12. Development of high-strength and high-RRR aluminum-stabilized superconductor for the ATLAS thin solenoid

    CERN Document Server

    Wada, K; Sakamoto, H; Shimada, T; Nagasu, Y; Inoue, I H; Tsunoda, K; Endo, S; Yamamoto, A; Makida, Y; Tanaka, K; Doi, Y; Kondo, T

    2000-01-01

    The ATLAS central solenoid magnet is being constructed to provide a magnetic field of 2 Tesla in the central tracking part of the ATLAS detector at the LHC. Since the solenoid coil is placed in front of the liquid-argon electromagnetic calorimeter, the solenoid coil must be as thin (and transparent) as possible. The high-strength and high- RRR aluminum-stabilized superconductor is a key technology for the solenoid to be thinnest while keeping its stability. This has been developed with an alloy of 0.1 wt% nickel addition to 5N pure aluminum and with the subsequent mechanical cold working of 21% in area reduction. A yield strength of 110 MPa at 4.2 K has been realized keeping a residual resistivity ratio (RRR) of 590, after a heat treatment corresponding to coil curing at 130 degrees C for 15 hrs. This paper describes the optimization of the fabrication process and characteristics of the developed conductor. (8 refs).

  13. High-Tc superconductor quantum interference devices

    International Nuclear Information System (INIS)

    1991-01-01

    This patent describes a superconductive quantum interferometric device for sensing a characteristic of a magnetic field. It comprises a substrate having a surface, the substrate being selected from the group which consists of strontium titanate, aluminum oxide, sapphire, ZrO 2 and mixtures thereof; a coating of MgO on the surface of the substrate; two identical thin-strip films of a high-critical temperature superconductor on the coating, each of the films having a pair of mutually parallel arms in the form of superconductor strips extending toward and aligned with super conductor strips forming corresponding arms of the other thin-strip film, and a crossbar strip connecting the arms of each thin-strip film at right angles to the arms, the high-critical-temperature superconductor being selected from the group which consists of yttrium-barium-calcium-copper-oxides, bismuth-strontium-calcium-copper-oxides, thallium-barium-copper-oxides, thallium-barium-calcium-copper-oxides, barium oxide: potassium oxide: bismuth oxides, and calcium oxide: zinc oxide: iron oxides; and insulating films on the coating between corresponding free ends of the arms thin-strip films, the insulating films being composed of a material selected from the group which consists of silicon dioxide, silicon nitride, magnesium oxide and mixture thereof

  14. Photographing magnetic fields in superconductors

    International Nuclear Information System (INIS)

    Harrison, R.B.; Wright, L.S.

    Magneto-optic techniques coupled with high-speed photography are being used to study the destruction of superconductivity by a magnetic field. The phenomenon of superconductivity will be introduced with emphasis placed on the properties of type I and type II superconductors in a magnetic field. The Faraday effect and its application to the study of the penetration of magnetic fields into these superconductors will be described; the relative effectiveness of some types of paramagnetic glass will be demonstrated. A number of cinefilms will be shown to illustrate the versatility of the magneto-optic method for observing flux motion and patterns. The analysis of data obtained from a high speed film (10,200 fps) of a flux jump in Nb-Zr will be presented and discussed

  15. High field superconductor development and understanding: A. Establishing the limits of performance of niobium titanium; B. Establishing whether Chevrel Phase materials can become useful high field superconductors

    International Nuclear Information System (INIS)

    Lee, P.J.; Jablonski, P.D.; Cooley, L.D.; Stejic, G.; Bonney, L.A.; Willis, T.C.; Larbalestier, D.C.

    1993-01-01

    The acquisition of a hydrostatic extrusion press now allows us to extrude composites under controlled conditions and enables us to fabricate new composite designs. We have successfully extruded a variety of composites including powder metallurgy APCs. Our conventional APC composite has been successfully brought to the completion of its fabrication. The results of the characterization of that composite have proven to be quite exciting. There is proof that the ''ideal'' microstructures that are hoped for in APC composites can be made. The flux pinning force of our APC composite is stronger than that for a conventional composite, despite having about half of the volume fraction of pins and a lower B c2 than occurs in a conventional composite. Additionally, the uniform nature of the microstructure makes our APC composite well-suited for more fundamental studies of flux pinning. We have fabricated thin film ''model'' conductors in order to understand basic flux-pinning mechanisms and these films have yielded interesting data on the importance of film geometry. Further advances have been made in increasing the J c of Chevrel Phase conductors and a clear path is now outlined for further improvement

  16. A new procedure for making TEM specimens of superconductor devices

    International Nuclear Information System (INIS)

    Huang, Y.; Merkle, K.L.

    1997-04-01

    A new procedure is developed for making TEM specimens of thin film devices. In this procedure the sample is flatly polished to an overall ion-mill-ready thickness so that any point in the 2-D sample pane can be thinned to an electron-transparent thickness by subsequent ion-milling. Using this procedure, small regions of interest can be easily reached in both cross-section and plan-view samples. This is especially useful in device studies. Applications of this procedure to the study of superconductor devices yield good results. This procedure, using commercially available equipment and relatively cheap materials, is simple and easy to realize

  17. The superconductor revolutions and the (slow) applications evolution

    International Nuclear Information System (INIS)

    Foner, S.

    1990-01-01

    The discovery in the 1960's of type 2 superconductors with high critical current densities in high magnetic fields (and the development of NbTi in particular) led to the first revolution. The discovery of high temperature superconductors (HTS) started the second revolution. At this stage ceramists became involved with superconductors. I will assess the status of various superconductor applications, progress of HTS and their possible applications at 4.2K, and near-term needs for superconducting materials operating at 30T in specialized facilities. Reasons for the slow growth of superconductor applications will be reviewed

  18. Topological insulators and topological superconductors

    CERN Document Server

    Bernevig, Andrei B

    2013-01-01

    This graduate-level textbook is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for graduate students and researchers preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with simple concepts such as Berry phases, Dirac fermions, Hall conductance and its link to topology, and the Hofstadter problem of lattice electrons in a magnetic field. It moves on to explain topological phases of matter such as Chern insulators, two- and three-dimensional topological insulators, and Majorana p-wave wires. Additionally, the book covers zero modes on vortices in topological superconductors, time-reversal topological superconductors, and topological responses/field theory and topolo...

  19. Correlations for developing film boiling effect in tubes

    International Nuclear Information System (INIS)

    Guo, Y.; Leung, L.K.H.

    2005-01-01

    Full text of publication follows: Reducing uncertainties in predicting film-boiling heat transfer can provide improved margins in reactor safety analysis, hence improved operating margins in nuclear power plants. Most reactor safety codes employed the tube-based prediction method for the fully developed film-boiling heat transfer coefficient. This approach tends to underpredict the heat-transfer coefficient and over-predict the sheath temperature at post-dryout conditions close to the CHF point. The under-prediction is due mainly to the droplet impingement on the heated surface and vapour superheating. This heat-transfer regime is referred to as the developing film boiling, which is associated with an enhancement in heat transfer compared to the fully developed film boiling. An improvement in the prediction accuracy is achievable by accounting for the effect of vapour-film development on film boiling heat transfer. In addition to system safety analyses, the prediction of developing film boiling heat transfer is required in subchannel analyses for fuel bundles. A tube-data-based prediction method is particularly relevant for subchannel applications. The objective of this study is to derive a correlation for the developing film boiling effect in tubes. The current CANDU R . system safety and subchannel analyses codes apply the look-up table approach to predict the film boiling heat transfer. The post-dryout look-up table provides the fully developed film boiling heat transfer in an 8-mm vertical tube, and has been extended to other tube sizes using a diameter modification factor. In this study, a modification factor has been developed to account for the developing film-boiling effect, and is expressed in the following non-dimensional form: K = (h FB - h FD )/(h NB - h FD ) = f ((T W - T sat )/T CHF - T sat )) where h FB is the film boiling heat transfer coefficient, h FD is the fully developed film-boiling heat transfer coefficient, which is evaluated using the film

  20. Trauma Films, Information Processing, and Intrusive Memory Development

    Science.gov (United States)

    Holmes, Emily A.; Brewin, Chris R.; Hennessy, Richard G.

    2004-01-01

    Three experiments indexed the effect of various concurrent tasks, while watching a traumatic film, on intrusive memory development. Hypotheses were based on the dual-representation theory of posttraumatic stress disorder (C. R. Brewin, T. Dalgleish, & S. Joseph, 1996). Nonclinical participants viewed a trauma film under various encoding conditions…

  1. Development and implementation of own software for dosimetry multichannel film

    International Nuclear Information System (INIS)

    Jimenez Feltstrom, D.; Reyes Garcia, R.; Luis Simon, F. J.; Carrasco Herrera, M.; Sanchez Carmona, G.; Herrador Cordoba, M.

    2013-01-01

    The objective of this work is to develop its own software for multichannel film dosimetry Radiochromic EBT2. Compare the results obtained with its use in multichannel and single-channel dosimetry. Check that the multi-channel dosimetry eliminates much of the artifacts caused by dirt, fingerprints, scratches, etc. Radiochromic in film and scanner devices. (Author)

  2. Low-Temperature Synthesis Routes to Intermetallic Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schaak, Raymond E

    2008-01-08

    Over the past few years, our group has gained expertise at developing low-temperature solution-based synthetic pathways to complex nanoscale solids, with particular emphasis on nanocrystalline intermetallic compounds. Our synthetic capabilities are providing tools to reproducibly generate intermetallic nanostructures with simultaneous control over crystal structure, composition, and morphology. This DOE-funded project aims to expand these capabilities to intermetallic superconductors. This could represent an important addition to the tools that are available for the synthesis and processing of intermetallic superconductors, which traditionally utilize high-temperature, high-pressure, thin film, or gas-phase vacuum deposition methods. Our current knowledge of intermetallic superconductors suggests that significant enhancements could result from the inherent benefits of low-temperature solution synthesis, e.g. metastable phase formation, control over nanoscale morphology to facilitate size-dependent property studies, robust and inexpensive processability, low-temperature annealing and consolidation, and impurity incorporation (for doping, stoichiometry control, flux pinning, and improving the critical fields). Our focus is on understanding the superconducting properties as a function of synthetic route, crystal structure, crystallite size, and morphology, and developing the synthetic tools necessary to accomplish this. This research program can currently be divided into two classes of superconducting materials: intermetallics (transition metal/post transition metal) and metal carbides/borides. Both involve the development and exploitation of low-temperature synthesis routes followed by detailed characterization of structures and properties, with the goal of understanding how the synthetic pathways influence key superconducting properties of selected target materials. Because of the low-temperature methods used to synthesize them and the nanocrystalline morphologies

  3. Studies on ceramic superconductors

    International Nuclear Information System (INIS)

    Chaklader, A.C.D.; Roemer, G.; Hardy, W.N.; Brewer, J.H.; Carolan, J.F.; Parsons, R.R.

    1987-01-01

    The superconducting properties of both bulk specimens and sputtered thin films of the YBa 2 Cu 3 O x compound have been studied. The bulk specimens were fabricated by cold pressing and sintering, and also by hot-pressing (subsequent reheating). The dc resistivity measurements showed a sharp drop in the temperature range 92-87K in this material. Muon spin relaxation (μSR) measurements of sintered discs in 3.4 kOe revealed the formation of a mixed state with an effective magnetic penetration depth λ ∼ 1365 angstrom at 6K, implying an effective charge carrier density of 6 x 10 21 cm -3 . The temperature dependence λ(T) is that of an ordinary s-wave superconductor. The resistivity of the thin film prepared from the compound by dc planar magnetron sputtering, showed a sharp drop to a very low value near 80K. The compound YBa 2 Cu 3 O x loses its superconducting properties, when either hot-pressed (in air) or oxidized at 500 degree C in high O 2 pressure, but this property can be restored when reheated in one atmosphere of O 2 above 900 degree C

  4. Processing of high-temperature superconductors at high strain rates

    International Nuclear Information System (INIS)

    Mamalis, A.G.; Pantazsopoulos, G.; Manolakos, D.E.; Szalay, A.

    2000-01-01

    This new book provides, for the first time, a systematic, unified presentation of all steps in the processing of high-temperature superconductor materials, ranging from synthesis of various systems to fabrication and industrial applications. Also covered are characterization techniques and current directions in research and development. The authors are leading specialists who bring to this new book their many years of experience in research, education and industrial engineering work in superconductor materials. This book is primarily focused on the bulk-fabrication techniques of high-temperature ceramic superconducting components, especially on the combination of dynamic powder-consolidation and subsequent deformation processing. The properties of these ceramics, which are difficult-to-form materials by applying conventional techniques, are combined for the net-shape manufacturing of such components for the construction of HTS deviceshor e llipsis. However, very important topics such as superconducting structures, chemical synthesis, film fabrication and characterization techniques are also reviewedhor e llipsis to provide a complete, comprehensive view of superconductors engineering

  5. Ceramic high-temperature superconductors

    International Nuclear Information System (INIS)

    Marquart, R.

    1989-01-01

    The contribution presents an overview treatment of the structure of the new superconductors (YBa 2 Cu 3 O 7-x ). Methods of powder production and processing technology are described, with current development projects by Dornier being taken into consideration. (orig.) [de

  6. Passivation of high temperature superconductors

    Science.gov (United States)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  7. Development of manufacturing capability for the fabrication of the Nb3Sn superconductor for the High Field Test Facility. Final report

    International Nuclear Information System (INIS)

    Spencer, C.R.

    Construction of High Field Test Facility (HFTF) at Lawrence Livermore Laboratory (LLNL) requires an extended surface Nb 3 Sn superconductor cable of carrying currents in excess of 7500 amperes in a 12 Tesla magnetic field. This conductor consists of a 5.4 mm x 11.0 mm superconducting core onto whose broad surfaces are soldered embossed oxygen free copper strips. Two different core designs have been developed and the feasibility of each design evaluated. Equipment necessary to produce the conductor were developed and techniques of production were explored

  8. Progress of metallic superconductors in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tachikawa, Kyoji, E-mail: tacsuper@keyaki.cc.u-tokai.ac.jp [Faculty of Engineering, Tokai University, 4-1-1, Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

    2013-01-15

    Highlights: ► Japanese contributions on the R and D of different metallic superconductors are summarized. ► Nb–Ti wires have been developed for MRI, accelerator, MAGLEV train and other applications. ► Multifilamentary Nb{sub 3}Sn wires with excellent performance have been developed for high-field use. ► Long-length Nb{sub 3}Al wires with promising strain tolerance have been fabricated by a new process. -- Abstract: This article overviews the development of metallic superconductors in Japan covering different kinds of alloys and intermetallic compounds. Metallic superconductors have opened many new application areas in science and technology. Japan has been one of the leading countries in the world, both in the research and development and in large-scale manufacturing of metallic superconductors.

  9. Out-of-equilibrium spin transport in mesoscopic superconductors.

    Science.gov (United States)

    Quay, C H L; Aprili, M

    2018-08-06

    The excitations in conventional superconductors, Bogoliubov quasi-particles, are spin-[Formula: see text] fermions but their charge is energy-dependent and, in fact, zero at the gap edge. Therefore, in superconductors (unlike normal metals) spin and charge degrees of freedom may be separated. In this article, we review spin injection into conventional superconductors and focus on recent experiments on mesoscopic superconductors. We show how quasi-particle spin transport and out-of-equilibrium spin-dependent superconductivity can be triggered using the Zeeman splitting of the quasi-particle density of states in thin-film superconductors with small spin-mixing scattering. Finally, we address the spin dynamics and the feedback of quasi-particle spin imbalances on the amplitude of the superconducting energy gap.This article is part of the theme issue 'Andreev bound states'. © 2018 The Author(s).

  10. Strain effects in oxide superconductors

    International Nuclear Information System (INIS)

    Wada, H.; Kuroda, T.; Sekine, H.; Yuyama, M.; Itoh, K.

    1991-01-01

    Strain sensitivities of superconducting properties are critical to high magnetic field applications of superconductors, since critical temperature, T c , upper critical field, H c2 , and critical current (density), I c (J c ), are all degraded under strains. Oxide superconductors so far known are all very fragile, thus requiring to be fabricated in the form of composite. In the case of practical metallic superconductors, such as Nb 3 Sn and V 3 Ga, the so-called bronze method has been developed where these superconducting intermetallics are enveloped in a ductile metallic sheath. Recently, a fabrication method similar to the bronze method has been developed for the Bi 2 Sr 2 Ca 2 Cu 3 O x superconductors using Ag tubes as sheath. In the present study mono- and multicore BiPbSrCaCuO tape conductors were prepared by means of this Ag-sheath composite method, and examined in terms of strain sensitivity by measuring their T c and I c (J c ) under bending or tensile strains. (orig.)

  11. Texture of high temperature superconductor thick films TI-1223 and TI-2223/LaAlO3 deposited by spray pyrolysis

    International Nuclear Information System (INIS)

    Nguyen Xuan, H.; Beauquis, S.; Galez, Ph.; Jorda, J.L.; Phok, S.; De-Barros, D.

    2004-01-01

    Superconducting TI-1223 and TI-2223 films have been prepared in a two steps process: deposition of Ba:Ca:Cu = 2:2:3 precursor by spray pyrolysis and ex-situ thallination. Pure textured TI-1223 films with good superconducting properties (T c =113 K and J c =0.7 MA/cm 2 at 77 K, 0T) have been obtained. Almost pure TI-2223 films have been obtained when precursor films have been thallinated with fluorinated sources. (orig.)

  12. Superconductor fluxoid logic

    International Nuclear Information System (INIS)

    Andronov, A.A.; Kurin, V.V.; Levichev, M.Yu.; Ryndyk, D.A.; Vostokov, V.I.

    1993-01-01

    In recent years there has been much interest in superconductor logical devices. Our paper is devoted to the analysis of some new possibilities in this field. The main problems here are: minimization of time of logical operations and reducing of device scale. Josephson systems are quite appropriate for this purpose because of small size, short characteristic time and also small energy losses. Two different types of Josephson logic have been investigated during last years. The first type is based on hysteretic V-A characteristic of a single Josephson junction. Superconducting and resistive (with nonzero voltage) states are considered as logical zero and logical unit. The second one - rapid single flux quantum logic, has been developed recently and is based on SQUID-like bistability. Different logical states are the states with different number of magnetic flux quanta inside closed superconducting contour. Information is represented by voltage pulses with fixed ''area'' (∫ V(t)/dt). This pulses are generated when logical state of SQUID-like elementary cell changes. The fundamental role of magnetic flux quantization in this type of logic leads to the necessity of large enough self-inductance of superconductor contour and thus to limitations on minimal device dimensions. (orig.)

  13. Flux cutting in superconductors

    International Nuclear Information System (INIS)

    Campbell, A M

    2011-01-01

    This paper describes experiments and theories of flux cutting in superconductors. The use of the flux line picture in free space is discussed. In superconductors cutting can either be by means of flux at an angle to other layers of flux, as in longitudinal current experiments, or due to shearing of the vortex lattice as in grain boundaries in YBCO. Experiments on longitudinal currents can be interpreted in terms of flux rings penetrating axial lines. More physical models of flux cutting are discussed but all predict much larger flux cutting forces than are observed. Also, cutting is occurring at angles between vortices of about one millidegree which is hard to explain. The double critical state model and its developments are discussed in relation to experiments on crossed and rotating fields. A new experiment suggested by Clem gives more direct information. It shows that an elliptical yield surface of the critical state works well, but none of the theoretical proposals for determining the direction of E are universally applicable. It appears that, as soon as any flux flow takes place, cutting also occurs. The conclusion is that new theories are required. (perspective)

  14. Preliminary Development of Conductivity based Test Method for Industrial Radiography Film Developer Solution

    International Nuclear Information System (INIS)

    Zainuddin, N.S.; Manah, N.S.A.; Khairul Anuar Mohd Salleh; Noorhazleena Azaman

    2015-01-01

    The strength of industrial radiography film developer solution is one of the most important aspects in radiography film processing. The developer solution reacts with the exposed film to visualize the latent image through chemical-film reaction. As the developer is repeatedly used, the strength decreases until a point where it cannot yield the required film optical density value. This work attempts to investigate the developer solution strength through its conductivity. Obtained data are cross correlated to the required industrial radiography optical density range. Through the experiment, the conductivity of the developer solution decreased as the number of the film processed increase. Thus, the desired optical density of the film cannot be achieved. The conductivity of developer is measured and recorded at interval of six films developed. The optical density of every film is recorded to analyze the change in optical density as the conductivity decreases. Through the procedure, it is suggested that as the conductivity decreases, the optical density of film decreased. Ultimately, the strength level of the developer solution can be determined. (author)

  15. Development of film dosimetric measurement system for verification of RTP

    International Nuclear Information System (INIS)

    Chen Yong; Bao Shanglian; Ji Changguo; Zhang Xin; Wu Hao; Han Shukui; Xiao Guiping

    2007-01-01

    Objective: To develop a novel film dosimetry system based on general laser scanner in order to verify patient-specific Radiotherapy Treatment Plan(RTP) in three-Dimensional Adaptable Radiotherapy(3D ART) and Intensity Modulated Radiotherapy (IMRT). Methods: Some advanced methods, including film saturated development, wavelet filtering with multi-resolution thresholds and discrete Fourier reconstruction are employed in this system to reduce artifacts, noise and distortion induced by film digitizing with general scanner; a set of coefficients derived from Monte Carlo(MC) simulation are adopted to correct the film over-response to low energy scattering photons; a set of newly emerging criteria, including γ index and Normalized Agreement Test (NAT) method, are employed to quantitatively evaluate agreement of 2D dose distributions between the results measured by the films and calculated by Treatment Planning System(TPS), so as to obtain straightforward presentations, displays and results with high accuracy and reliability. Results: Radiotherapy doses measured by developed system agree within 2% with those measured by ionization chamber and VeriSoft Film Dosimetry System, and quantitative evaluation indexes are within 3%. Conclusions: The developed system can be used to accurately measure the radiotherapy dose and reliably make quantitative evaluation for RTP dose verification. (authors)

  16. Fine uniform filament superconductors

    Science.gov (United States)

    Riley, Jr., Gilbert N.; Li, Qi; Roberts, Peter R.; Antaya, Peter D.; Seuntjens, Jeffrey M.; Hancock, Steven; DeMoranville, Kenneth L.; Christopherson, Craig J.; Garrant, Jennifer H.; Craven, Christopher A.

    2002-01-01

    A multifilamentary superconductor composite having a high fill factor is formed from a plurality of stacked monofilament precursor elements, each of which includes a low density superconductor precursor monofilament. The precursor elements all have substantially the same dimensions and characteristics, and are stacked in a rectilinear configuration and consolidated to provide a multifilamentary precursor composite. The composite is thereafter thermomechanically processed to provide a superconductor composite in which each monofilament is less than about 50 microns thick.

  17. Electronic structure and superconductivity of FeSe-related superconductors.

    Science.gov (United States)

    Liu, Xu; Zhao, Lin; He, Shaolong; He, Junfeng; Liu, Defa; Mou, Daixiang; Shen, Bing; Hu, Yong; Huang, Jianwei; Zhou, X J

    2015-05-13

    FeSe superconductors and their related systems have attracted much attention in the study of iron-based superconductors owing to their simple crystal structure and peculiar electronic and physical properties. The bulk FeSe superconductor has a superconducting transition temperature (Tc) of ~8 K and it can be dramatically enhanced to 37 K at high pressure. On the other hand, its cousin system, FeTe, possesses a unique antiferromagnetic ground state but is non-superconducting. Substitution of Se with Te in the FeSe superconductor results in an enhancement of Tc up to 14.5 K and superconductivity can persist over a large composition range in the Fe(Se,Te) system. Intercalation of the FeSe superconductor leads to the discovery of the AxFe2-ySe2 (A = K, Cs and Tl) system that exhibits a Tc higher than 30 K and a unique electronic structure of the superconducting phase. A recent report of possible high temperature superconductivity in single-layer FeSe/SrTiO3 films with a Tc above 65 K has generated much excitement in the community. This pioneering work opens a door for interface superconductivity to explore for high Tc superconductors. The distinct electronic structure and superconducting gap, layer-dependent behavior and insulator-superconductor transition of the FeSe/SrTiO3 films provide critical information in understanding the superconductivity mechanism of iron-based superconductors. In this paper, we present a brief review of the investigation of the electronic structure and superconductivity of the FeSe superconductor and related systems, with a particular focus on the FeSe films.

  18. Development of in-situ control diagnostics for application of epitaxial superconductor and buffer layers

    Energy Technology Data Exchange (ETDEWEB)

    B.C. Winkleman; T.V. Giel; Jason Cunningham

    1999-07-30

    The recent achievements of critical currents in excess of 1 x 10{sup 6} amp/cm{sup 2} at 77 K in YBCO deposited over suitably textured buffer/substrate composites have stimulated interest in the potential fabrication of these coated conductors as wire. Numerous approaches and manufacturing schemes for producing coated conductor wire are currently being developed. Recently, under the US DOE's sponsorship, the University of Tennessee Space Institute performed an extensive evaluation of leading coated conductor processing options. In general, it is their feeling that the science and chemistry that are being developed in the coated conductor wire program now need proper engineering evaluation to define the most viable options for a commercial fabrication process. All fabrication processes will need process control measurements. This report provides a specific review of the needs and available technologies for process control for many of the coated conductor processing options. This report also addresses generic process monitoring areas in which additional research and development is needed. The concentration is on the two different approaches for obtaining the textured substrates that have been identified as viable candidates. These are the Los Alamos National Laboratory's ion-beam assisted deposition, called IBAD, to obtain a highly textured yttria-stabilized zirconia (YSZ) buffer on nickel alloy strips, and Oak Ridge National Laboratory's rolling assisted, bi-axially textured substrate option called RABiTS{trademark}.

  19. DEVELOPMENT OF IN-SITU CONTROL DIAGNOSTICS FOR APPLICATION OF EPITAXIAL SUPERCONDUCTOR AND BUFFER LAYERS

    Energy Technology Data Exchange (ETDEWEB)

    B.C. Winkleman; T.V. Giel, Jr.; J. Cunningham

    1999-06-30

    The recent achievements of critical currents in excess of 1x10{sup 6}amp/cm{sup 2} at 77K in YBCO deposited over suitably textured buffer/substrate composites have stimulated interest in the potential fabrication of these coated conductors as wire. Numerous approaches and manufacturing schemes for producing coated conductor wire are currently being developed. Recently, under the U. S. Department of Energy (DOE's) sponsorship, the University of Tennessee Space Institute (UTSI) performed an extensive evaluation of leading coated conductor processing options. In general, it is our feeling that the science and chemistry that are being developed in the coated conductor wire program now need proper engineering evaluation to define the most viable options for a commercial fabrication process. All fabrication processes will need process control measurements. This report provides a specific review of the needs and available technologies for process control for many of the coated conductor processing options. This report also addresses generic process monitoring areas in which additional research and development is needed. The concentration is on the two different approaches for obtaining the textured substrates that have been identified as viable candidates. These are the Los Alamos National Laboratory's (LANL) ion-beam assisted deposition, called IBAD, to obtain a highly textured yttria-stabilized zirconia (YSZ) buffer on nickel alloy strips, and Oak Ridge National Laboratory's (ORNL) rolling assisted, bi-axially textured substrate option called RABiTS{trademark}.

  20. Research On Bi-Based High-Temperature Superconductors

    Science.gov (United States)

    Banks, Curtis; Doane, George B., III; Golben, John

    1993-01-01

    Brief report describes effects of melt sintering on Bi-based high-temperature superconductor system, as well as use of vibrating-sample magnetometer to determine hysteresis curves at 77 K for partially melt-sintered samples. Also discussed is production of high-temperature superconducting thin films by laser ablation: such films potentially useful in detection of signals of very low power.

  1. Advances in and prospects for development of high-temperature superconductor rotating machines at Siemens

    International Nuclear Information System (INIS)

    Neumueller, H W; Nick, W; Wacker, B; Frank, M; Nerowski, G; Frauenhofer, J; Rzadki, W; Hartig, R

    2006-01-01

    We report on the successful manufacture and testing of the Siemens 400 kVA HTS synchronous motor, which has been in operation for over 3 years, and on the progress of the 4 MVA synchronous motor/generator, which has been manufactured and is now in a phase of extended testing. Furthermore, the benefits of HTS machines will be discussed with emphasis on applications in ships. The development of future marketable products will be strongly dependent on the progress of secondary technologies, such as wire performance and efficient cost-effective refrigerators

  2. Development of high performance Nb-Ti(Fe) multifilamentary superconductor for the LHC insertion quadrupoles

    CERN Document Server

    Lee, P J; Gabr-Rayan, W; Larbalestier, D C; Naus, M T; Squitieri, A A; Starch, W L; Barzi, E; Limon, P J; Sabbi, G L; Zlobin, A V; Kanithi, H; Hong, S; McKinnell, J C; Neff, D

    1999-01-01

    A development program was initiated in order to develop strand with improved current density at 10.5 T and 1.9 K over existing SSCL designs. The two successful strand designs reported on here both utilized high Fe content Nb-47 wtTi $9 alloys to improve the critical current density at high field by 7 At 10.5 T and 1.9 K, critical current densities exceeding 1450 A/mm/sup 2/ were obtained. In this paper we report detailed quantification of the macro- and micro- $9 structures of these strands and correlate these with critical current density measurements at 1.9 K and 4.2 K. The high Fe content significantly reduced the alpha -Ti precipitate size. The linear relationship between critical current $9 density and precipitate volume found is in agreement with earlier studies. High resolution FESEM electron backscatter contrast suggests a thin layer of high atomic number at grain boundaries. (12 refs).

  3. Force measurements for levitated bulk superconductors

    International Nuclear Information System (INIS)

    Tachi, Y.; Sawa, K.; Iwasa, Y.; Nagashima, K.; Otani, T.; Miyamoto, T.; Tomita, M.; Murakami, M.

    2000-01-01

    We have developed a force measurement system which enables us to directly measure the levitation force of levitated bulk superconductors. Experimental data of the levitation forces were compared with the results of numerical simulation based on the levitation model that we deduced in our previous paper. They were in fairly good agreement, which confirms that our levitation model can be applied to the force analyses for levitated bulk superconductors. (author)

  4. Force measurements for levitated bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tachi, Y. [Department of Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama (Japan); ISTEC, Superconductivity Research Laboratory, 1-16-25 Shibaura, Minato-ku, Tokyo (Japan). E-mail: tachi at istec.or.jp; Uemura, N. [Department of Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama (Japan); ISTEC, Superconductivity Research Laboratory, 1-16-25 Shibaura, Minato-ku, Tokyo (Japan); Sawa, K. [Department of Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama (Japan); Iwasa, Y. [Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA (United States); Nagashima, K. [Railway Technical Research Institute, Hikari-cho, Kokubunji-shi, Tokyo (Japan); Otani, T.; Miyamoto, T.; Tomita, M.; Murakami, M. [ISTEC, Superconductivity Research Laboratory, 1-16-25 Shibaura, Minato-ku, Tokyo (Japan)

    2000-06-01

    We have developed a force measurement system which enables us to directly measure the levitation force of levitated bulk superconductors. Experimental data of the levitation forces were compared with the results of numerical simulation based on the levitation model that we deduced in our previous paper. They were in fairly good agreement, which confirms that our levitation model can be applied to the force analyses for levitated bulk superconductors. (author)

  5. Development of high field superconductors for fusion energy applications. Final report

    International Nuclear Information System (INIS)

    1985-01-01

    The purpose of this project was to develop a conductor design and a manufacturing procedure for a composite multifilamentary Nb 3 Sn conductor suitable for winding a magnet for use in a fusion energy power plant. Effort was concentrated on the design of a conductor with tubular niobium filaments in a copper matrix. Bronze in the bores of the filaments would react with the niobium to form Nb 3 Sn on the inside diameter of the niobium tubular filaments during a heat treatment at final size. Four filament geometries were evaluated. The addition of titanium to the bronze was found to increase the current density. The use of a hydrogen atmosphre did not appear to cause any increase in current density. Primary billets were assembled and extruded with five tubular filament designs and for comparison, five rod type filament designs. Billet designs are described

  6. 'Beautiful' unconventional synthesis and processing technologies of superconductors and some other materials

    Directory of Open Access Journals (Sweden)

    Petre Badica, Adrian Crisan, Gheorghe Aldica, Kazuhiro Endo, Hanna Borodianska, Kazumasa Togano, Satoshi Awaji, Kazuo Watanabe, Yoshio Sakka and Oleg Vasylkiv

    2011-01-01

    Full Text Available Superconducting materials have contributed significantly to the development of modern materials science and engineering. Specific technological solutions for their synthesis and processing helped in understanding the principles and approaches to the design, fabrication and application of many other materials. In this review, we explore the bidirectional relationship between the general and particular synthesis concepts. The analysis is mostly based on our studies where some unconventional technologies were applied to different superconductors and some other materials. These technologies include spray-frozen freeze-drying, fast pyrolysis, field-assisted sintering (or spark plasma sintering, nanoblasting, processing in high magnetic fields, methods of control of supersaturation and migration during film growth, and mechanical treatments of composite wires. The analysis provides future research directions and some key elements to define the concept of 'beautiful' technology in materials science. It also reconfirms the key position and importance of superconductors in the development of new materials and unconventional synthesis approaches.

  7. Superconductors with excess quasiparticles

    International Nuclear Information System (INIS)

    Elesin, V.F.; Kopaev, Y.V.

    1981-01-01

    This review presents a systematic kinetic theory of nonequilibrium phenomena in superconductors with excess quasiparticles created by electromagnetic or tunnel injection. The energy distributions of excess quasiparticles and of nonequilibrium phonons, dependence of the order parameter on the power and frequency (or intensity) of the electromagnetic field, magnetic properties of nonequilibrium superconductors, I-V curves of superconductor-insulator-superconductor junctions, and other properties are described in detail. The stability of superconducting states far from thermodynamic equilibrium is investigated and it is shown that characteristic instabilities leading to the formation of nonuniform states of a new type or phase transitions of the first kind are inherent to superconductors with excess quasiparticles. The results are compared with experimental data

  8. Superconductor digital electronics

    International Nuclear Information System (INIS)

    Likharev, Konstantin K.

    2012-01-01

    The objective of these notes is to offer a brief review of the history of superconductor digital electronics, and discuss prospects of its future development. Due to length restrictions, many important technical contributions could not be mentioned at all - with sincere apologies to their authors. Though an attempt has been made to give an unbiased review of the most important work all over the world, a special emphasis on the efforts in the former Soviet Union, which had not been discussed much in literature, and in which the author of this text took an active part, seemed excusable. Another important qualification is that the author phased out his own research in the field about 10 years ago, so that the last parts of the notes, devoted to present-time and future work, should be viewed as not much more than remarks by an (interested) outsider.

  9. Fabrication of high temperature superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam; Dorris, Stephen E.; Ma, Beihai; Li, Meiya

    2003-06-17

    A method of forming a biaxially aligned superconductor on a non-biaxially aligned substrate substantially chemically inert to the biaxially aligned superconductor comprising is disclosed. A non-biaxially aligned substrate chemically inert to the superconductor is provided and a biaxially aligned superconductor material is deposited directly on the non-biaxially aligned substrate. A method forming a plume of superconductor material and contacting the plume and the non-biaxially aligned substrate at an angle greater than 0.degree. and less than 90.degree. to deposit a biaxially aligned superconductor on the non-biaxially aligned substrate is also disclosed. Various superconductors and substrates are illustrated.

  10. High temperature superconductor bulk materials. Fundamentals - processing - properties control - application aspects

    International Nuclear Information System (INIS)

    Krabbes, G.; Fuchs, G.; Canders, W.R.; May, H.; Palka, R.

    2006-01-01

    This book presents all the features of bulk high temperature superconducting materials. Starting from physical and chemical fundamentals, the authors move on to portray methods and problems of materials processing, thoroughly working out the characteristic properties of bulk superconductors in contrast to long conductors and films. The authors provide a wide range of specific materials characteristics with respect to the latest developments and future applications guiding from fundamentals to practical engineering examples. This book contains the following chapters: 1. Fundamentals 2. Growth and melt processing of YBCO 3. Pinning-relevant defects in bulk YBCO 4. Properties of bulk YBCO 5. Trapped fields 6. Improved YBCO based bulk superconductors and functional elements 7. Alternative systems 8. Peak effect 9. Very high trapped fields in YBCO permanent magnets 10. Engineering aspects: Field distribution in bulk HTSC 11. Inherently stable superconducting magnetic bearings 12. Application of bulk HTSCs in electromagnetic energy converters 13. Applications in magnet technologies and power supplies

  11. Development of peelable films for decontamination and their performances

    International Nuclear Information System (INIS)

    Yang Enbo; Xu Baolan; Zhao Xiuyan

    1990-01-01

    Two kinds of peelable films have been developed which can be coated on surface contaminated by radioactivity for decontamination purposes. Very high levels of radioactive decontamination, especially on smooth surface, are obtained after one application. 90-99% decontamination based on initial activity can be obtained for stainless steel, PVC floor and glass

  12. Recent development in crystal growth of large-diameter Y-QMG (reg sign) bulk superconductors; Y kei ogata QMG (reg sign) baruku koonchodendotai no kaihatsu jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, T.; Morita, M. [Nippon Steel Corporation, Tokyo (Japan); Masahashi, N. [Tohoku University, Miyagi (Japan). Institute for Materials Research

    1999-11-25

    The current status of large-diameter Y-Ba-Cu-O OMG(reg sign) bulk superconductors is described. 75 mm-diameter QMG(reg sign) samples with fairly concentric trapped-magnetic-flux-density distributions have been successfully grown. In addition, a record-high value of the magnetic levitation force, 171 kgf, measured at 77 K using a 90 mm-diameter Nd-Fe-B magnet has been obtained for a 100 mm-diameter sample. The crystal orientation of subgrains in the sample was determined using Electron Back-Scattering Diffraction as well as using a conventional optical apparatus including a He-Ne-laser. For the sample grown under normal process conditions, the maximum value of the [001]-axis misorientation angles at the subgrain-boundaries we obtained in the c-substructure region is 2.9 degree. However, in the a/b-substructure regions, the misorientation angles are larger, and the maximum value obtained is 6.6 degree, exceeding the critical angle at which a significant reduction of the critical current density occurs in Y123 thin films due to the weak-link problem. (author)

  13. Large area bulk superconductors

    Science.gov (United States)

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  14. Friction in levitated superconductors

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1988-01-01

    A type I superconductor levitated above a magnet of low symmetry has a unique equilibrium position about which it may oscillate freely. In contrast, a type II superconductor has a continuous range of stable equilibrium positions and orientations where it floats rigidly without swinging or orbiting as if it were stuck in sand. A strong internal friction conspicuously indicates the existence and unpinning of flux lines in oxide superconductors levitated above liquid nitrogen. It is shown how these effects follow from the hysteretic magnetization curves and how the energy is dissipated

  15. Applications of high-temperature superconductors in power technology

    International Nuclear Information System (INIS)

    Hull, John R

    2003-01-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications

  16. High Tc superconductors using solution techniques

    International Nuclear Information System (INIS)

    Barboux, P.; Valente, I.; Henry, M.; Morineau, R.; Tarascon, J.M.; Khan, S.; Shokoohi, F.; Bagley, B.G.

    1989-01-01

    The authors have investigated different solution techniques to synthesize the Cu-based superconductors in the thick film form. Thick films of YBa 2 Cu 3 O 7 have been produced using controlled precipitation techniques. Bi-based and Tl-based materials have been deposited by spraying of ionic solutions. The numerous difficulties encountered during each process are analyzed in order to propose new synthesis procedures such as a new method, based on the precipitation of hydroxides only, which is described as a prospective for lowering the synthesis temperature and shortening the reaction time

  17. Microstructure and property correlations in high-temperature superconductors

    Science.gov (United States)

    Kalyanaraman, Ramakrishnan

    1998-11-01

    The work in this dissertation is intended at developing high quality device gradefilms of the high temperature (high-Tsbc) superconductor, Yttrium Barium Copper Oxide (YBCO), on MgO(001) substrates. Three approaches have been used to achieve the above goal, (i) The use of a SrTiOsb3 buffer layer, (ii) The use of Ag to enhance the growth of YBCO films and (iii) Investigation of the atomic structure-property correlations of low-angle grain boundaries in these films. Thin film heterostructures of YBCO/MgO and YBCO/SrTiOsb3/MgO were fabricated by pulsed laser deposition (PLD), using a 248 nm KrF excimer laser. Analysis of the structure and measurement of superconducting properties of the films were carried out to optimize the suitable conditions under each approach. The key findings were, (i) Single crystal-like SrTiOsb3 buffer layers can be grown and they give the highest JsbcYBCO films, (ii) An in-depth study of the role of Ag showed that it enhanced film growth of YBCO thereby improving its quality, and (iii) Low-angle boundaries in YBCO/MgO occur with two probable habit planes and the Jsbcs across them differ slightly. A systematic investigation of the crystalline quality of the SrTiOsb3 films deposited by PLD was performed as a function of oxygen partial pressure (pOsb2) and substrate temperature (Tsbc). The highest quality films were grown in the pOsb2 range of 0.1-1 mTorr at 750sp°C. The films had as-deposited x-ray diffraction rocking curve (omega) values of {˜}0.70sp° and Rutherford backscattering channeling yields (chisbmin) of 5% as compared to omega˜1.40sp° and chisbmin˜14% for the film deposited in 100 mTorr of pOsb2. The x-ray phi-scans showed epitaxial cube-on-cube alignment of the SrTiOsb3 films on MgO(001) substrates. Thermal annealing of the SrTiOsb3 films further improved the quality, and the 1 mTorr films gave omega{˜}0.13sp° and chisbmin˜2.0%. Transmission electron microscopy investigations (TEM) of these films showed that the defects in

  18. The Effective Coherence Length in Anisotropic Superconductors

    International Nuclear Information System (INIS)

    Polturak, E.; Koren, G.; Nesher, O

    1999-01-01

    If electrons are transmitted from a normal conductor(N) into a superconductor(S), common wisdom has it that the electrons are converted into Cooper pairs within a coherence length from the interface. This is true in conventional superconductors with an isotropic order parameter. We have established experimentally that the situation is rather different in high Tc superconductors having an anisotropic order parameter. We used epitaxial thin film S/N bilayers having different interface orientations in order to inject carriers from S into N along different directions. The distance to which these carriers penetrate were determined through their effect on the Tc of the bilayers. We found that the effective coherence length is 20A only along the a or b directions, while in other directions we find a length of 250dr20A out of plane, and an even larger value for in-plane, off high symmetry directions. These observations can be explained using the Blonder-Tinkham-Klapwijk model adapted to anisotropic superconductivity. Several implications of our results on outstanding problems with high Tc junctions will be discussed

  19. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    International Nuclear Information System (INIS)

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-01-01

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

  20. Review of progress in pulsed laser deposition and using Nd:YAG laser in processing of high Tc superconductors

    International Nuclear Information System (INIS)

    Chen, C.W.; Mukherjee, K.

    1993-01-01

    The current progress in pulsed laser ablation of high-temperature superconductors is reviewed with emphasis on the effect of pulse-width and wavelength, nature of the plasma plume, post-annealing and methods to improve quality of films grown at low temperature. An ion beam assisted millisecond pulsed laser vapor deposition process has been developed to fabricate YBa 2 Cu 3 O x high T. superconductor thin films. Solution to target overheating problem, effects of oxygen ion beam, properties of deposited films, and effect of silver buffer layer on YSZ substrate are presented. A new laser calcining process has been used to produce near single phase high T c superconductors of Bi-Pb-Sr-Ca-Cu-0 system. The total processing time was reduced to about 100 hours which is about half of that for conventional sintering. For this compound both resistance and magnetic susceptibility data showed an onset of superconducting transition at about 110K. A sharp susceptibility drop was observed above 106K. The zero resistance temperature was about 98K. High T c phase was formed via a different kinetic path in laser calcined sample compare with the conventionally processed sample

  1. Kohn anomalies in superconductors

    International Nuclear Information System (INIS)

    Flatte, M.E.

    1994-01-01

    The detailed behavior of phonon dispersion curves near momenta which span the electronic Fermi sea in a superconductor is presented. An anomaly, similar to the metallic Kohn anomaly, exists in a superconductor's dispersion curves when the frequency of the photon spanning the Fermi sea exceeds twice the superconducting energy gap. This anomaly occurs at approximately the same momentum but is stronger than the normal-state Kohn anomaly. It also survives at finite temperature, unlike the metallic anomaly. Determination of Fermi-surface diameters from the location of these anomalies, therefore, may be more successful in the superconducting phase than in the normal state. However, the superconductor's anomaly fades rapidly with increased phonon frequency and becomes unobservable when the phonon frequency greatly exceeds the gap. This constraint makes these anomalies useful only in high-temperature superconductors such as La 1.85 Sr 0.15 CuO 4

  2. Formation of hot spots in a superconductor observed by low-temperature scanning electron microscopy

    International Nuclear Information System (INIS)

    Eichele, R.; Seifert, H.; Huebener, R.P.

    1981-01-01

    Low-temperature scanning electron microscopy can be used for the direct observation of hot spots in a superconductor. Experiments performed at 2.10 K with tim films demonstrating the method are reported

  3. Topological superconductors: a review.

    Science.gov (United States)

    Sato, Masatoshi; Ando, Yoichi

    2017-07-01

    This review elaborates pedagogically on the fundamental concept, basic theory, expected properties, and materials realizations of topological superconductors. The relation between topological superconductivity and Majorana fermions are explained, and the difference between dispersive Majorana fermions and a localized Majorana zero mode is emphasized. A variety of routes to topological superconductivity are explained with an emphasis on the roles of spin-orbit coupling. Present experimental situations and possible signatures of topological superconductivity are summarized with an emphasis on intrinsic topological superconductors.

  4. Room temperature superconductors

    International Nuclear Information System (INIS)

    Sleight, A.W.

    1995-01-01

    If the Holy Grail of room temperature superconductivity could be achieved, the impact on could be enormous. However, a useful room temperature superconductor for most applications must possess a T c somewhat above room temperature and must be capable of sustaining superconductivity in the presence of magnetic fields while carrying a significant current load. The authors will return to the subject of just what characteristics one might seek for a compound to be a room temperature superconductor. 30 refs., 3 figs., 1 tab

  5. Continuous lengths of oxide superconductors

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2000-01-01

    A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.

  6. Evaluation of a new self-developing instant film for imaging and dosimetry

    International Nuclear Information System (INIS)

    Watanabe, Y.; Patel, G. N.; Patel, P.

    2006-01-01

    Radiation sensitive films are standard dosimetric tools in radiation therapy. Films are used for machine quality assurance (QA) and treatment planning software evaluation. With the advent of intensity modulated radiation therapy (IMRT), simple and fast imaging technology is needed for patient-specific verification of radiation fields. Conventional radiographic films are often used. Radiochromic films, e.g. Gafchromic films, were recently introduced to the market. But these films have some disadvantages. JP Laboratories have developed a prototype radiochromic film, called SIFID (self-developing, instant film for imaging and dosimetry) with superior performance such that SIFID is unaffected by ambient light for months, stable up to 90 deg. C and can be archived. SIFID is made of polymerizable diacetylene. The film develops blue colour instantly upon absorbing radiation. We evaluated the film for radiation therapy applications. Our preliminary data demonstrate its feasibility as a dosimetric tool for IMRT QA as well as for other applications. (authors)

  7. Defect formation and carrier doping in epitaxial films of the ''parent'' compound SrCuO2: Synthesis of two superconductors descendants

    International Nuclear Information System (INIS)

    Feenstra, R.; Norton, D.P.; Budai, J.D.; Jones, E.C.; Christen, D.K.; Kawai, T.

    1995-04-01

    The infinite layer or parent compounds ACuO 2 (A: Ca-Sr-Ba) constitute the simplest copper oxygen perovskites that contain the CuO 2 sheets essential for superconductivity. The stabilization of these basic ''building blocks'' as epitaxial films, therefore, provides alluring opportunities towards the search for new superconducting compounds and elucidation of the underlying mechanisms. In this work, general trends of the defect formation and carrier doping for epitaxial films of the intermediate endmember SrCuO 2 are reviewed. First results are presented from successful attempts to induce hole-doped superconductivity via the processing-controlled incorporation of charge reservoir layers

  8. Complex composition film condensation in the sluice device of an electron microscope

    International Nuclear Information System (INIS)

    Kukuev, V.I.; Lesovoj, M.V.; Vlasov, D.A.; Malygin, M.V.; Domashevskaya, Eh.P.; Tomashpol'skij, Yu.Ya.

    1994-01-01

    Based on the sluice device of an electron microscope a system is developed for material laser evaporation and vapor condensation on a substrate, situated in the microscope specimen holder. Substrate heating by laser radiation to 100 deg C is used. The system is applied for investigating growth of high-temperature superconductor films

  9. Achievement report on developing superconductor power applied technologies in fiscal 1999 (2). Research and development of superconductor wire materials, research and development of superconductor power generators, research of total systems, research and development of freezing systems, and verification tests; 1999 nendo chodendo denryoku oyo gijutsu kaihatsu seika hokokusho. 2. Chodendo senzai no kenkyu kaihatsu / chodendo hatsudenki no kenkyu kaihatsu / total system no kenkyu / reito system no kenkyu kaihatsu / jissho shiken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    With an objective to achieve higher efficiency, higher density, and higher stability in power systems, research and development has been performed on superconductor power generators. This paper summarizes the achievements thereof in fiscal 1999. A verification test was given on the rotor of an ultra high speed responding generator. In a sudden short circuit test using the different phase charging method, no anomalies were found such as quench generation and vibration changes, wherein the healthiness of the generator was verified. In the VVVF actuation test, knowledge was acquired on the actuation method when the ultra high speed responding generator is applied to a combined cycle plant. After the verification test has been completed, the disassembly inspections such as visual check and non-destructive test were performed. With regard to the vacuum leakage found in the rotor under very low temperatures, the causes were presumed and the countermeasures were discussed by observing the weld structures. In the design research, the conception design on the 200-MW pilot generator was reviewed by reflecting the results of the verification tests on the model generator. At the same time, trial design was made on a 600-MW target generator. In summarizing the overall research achievements, the achievements and evaluations were summarized on technological issues that have been allotted to each research member. (NEDO)

  10. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and

  11. Development and utilization of liquid quartz light modulating film. Ekisho choko film no kaihatsu to riyo

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, M. (Ajinomoto Co. Inc., Tokyo (Japan))

    1992-03-01

    This paper introduces the polymer dispersed liquid crystal (PDLC) ACT'' sheet, a liquid quartz light modulating film, developed by the Ajinomoto Company in Japan. A mixture of liquid crystal and polymer precursor is sandwiched between polyethylene terephthalate films imparted with transparency conductor made of indium tin oxide (ITO), which is then polymerized by heating or irradiating ultraviolet rays to obtain a PDLC. The film has a thickness as thin as about 0.3 mm, and good processibility. The sheet uses light modulating elements functioning on scatter and permeation of light. Clarification was made on the voltage dependence of cloudiness, total light permeability, straight and parallel light permeability, the response, and the operating voltage. The system consumes small amount of power with a threshold value of about 35V, and is suitable to operate large areas when working on the utility power supply. An incident light having a high diffusion capability when the electric field is turned off exhibits a high clouding function. The system gives an excellent feel of colorlessness and transparency when the electric field is turned on. The performances in heat insulation, infrared reflection capability and noise resistance are expected to be compounded for a functional versatility. 4 refs., 6 figs., 2 tabs.

  12. Propagation of normal zones in composite superconductors

    International Nuclear Information System (INIS)

    Dresner, L.

    1976-08-01

    This paper describes calculations of propagation velocities of normal zones in composite superconductors. Full accounting is made for (1) current sharing, (2) the variation with temperature of the thermal conductivity of the copper matrix, and the specific heats of the matrix and the superconductor, and (3) the variation with temperature of the steady-state heat transfer at a copper-helium interface in the nucleate-boiling, transition, and film-boiling ranges. The theory, which contains no adjustable parameters, is compared with experiments on bare (uninsulated) conductors. Agreement is not good. It is concluded that the effects of transient heat transfer may need to be included in the theory to improve agreement with experiment

  13. Conductive polymer/superconductor bilayer structures

    International Nuclear Information System (INIS)

    McDevitt, J.T.; Haupt, S.G.; Riley, D.R.; Zhao, J.; Grassi, J.; Lo, R.K.; Jones, C.

    1994-01-01

    The preparation of a hybrid conducting polymer/high-temperature superconductor device consisting of a polypyrrole-coated YBa 2 Cu 3 O 7-∂ microbridge is reported. Electrochemical techniques are exploited to alter the oxidation state of the polymer and, in doing so, it is found for the first time that superconductivity can be modulated in a controllable and reproducible fashion by a polymer layer. Whereas the neutral (insulating) polypyrrole only slightly influences the electrical properties of the underlying YBa 2 Cu 3 O 7-∂ film, the oxidized (conductive) polymer depresses Tc by up to 50K. In a similar fashion, the oxidation state of the polymer is found to modulate reversibly the magnitude of J c , the superconducting critical current. Thus, a new type of molecular switch for controlling superconductivity is demonstrated. Electrochemical, resistance vs. temperature, conact resistance, atomic force microscopy and scanning electron microscopy measurements are utilized to explore the polymer/superconductor interactions

  14. Flux Pinning and AC Loss in Second Generation High Temperature Superconductor Wires

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, Mariappan Parans [ORNL; Selvamanickam, V. [SuperPower Incorporated, Schenectady, New York

    2007-01-01

    Major advances have been made in the last 18 years in high-temperature superconductor (HTS) reserach and development, resulting in increased use of HTS materials in commerical and pre-commercial electric-power applications. This new and important book addresses the issues related to flux pinning, AC losses and thick YBCO film growth. Written by top most scientists in the world, it presents the current status and issues related to YBCO coated conductors and the need for further fundamental materials science work in YBCO coated conductor. It will be a useful handbook for years to come.

  15. Tunneling spectroscopy on grain boundary junctions in electron-doped high-temperature superconductors

    International Nuclear Information System (INIS)

    Welter, B.

    2007-01-01

    Some methods are developed anf presented, by means of which from experimental tunnel spectra, especially on symmetric SIS contacts, informations about the properties of electrodes and tunnel barriers can be obtained. Especially a procedure for the numerical unfolding of symmetric SIS spectra is proposed. Furthermore a series of models is summarized, which can explain the linear background conductivity observed in many spectra on high-temperature superconductors. The results of resistance measurements on film bridges are presented. Especially different methods for the determination of H c2 (T) respectively H c2 (0) are presented and applied to the experimental data. Finally the results of the tunnel-spectroscopy measurements are shown

  16. Orientational and positional order in flux lattices of type-II superconductors

    International Nuclear Information System (INIS)

    Chudnovsky, E.M.

    1991-01-01

    A detailed theory of a hexatic vortex glass, recently observed in high-T c superconductors, is developed. The vortex lattice in this phase is characterized by short-range positional order, which decays as exp(-αr) in three dimensions (3D) and as exp(-βr 2 ) in 2D, and by extended orientational correlations, which may be long range in a 3D sample and decay algebraically in a 2D film. For 2D and 3D the angular and field dependence of positional and orientational correlation functions is obtained; these may be easily tested experimentally

  17. Ivar Giaever, Tunneling, and Superconductors

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis Ivar Giaever, Tunneling, and Superconductors Resources with in Superconductors Measured by Electron Tunneling; Physical Review Letters, Vol. 5 Issue 4: 147 - 148 ; August 15, 1960 Electron Tunneling Between Two Superconductors; Physical Review Letters, Vol. 5 Issue 10

  18. Granular Superconductors and Gravity

    Science.gov (United States)

    Noever, David; Koczor, Ron

    1999-01-01

    As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (approx. 10(exp -6) g cu cm). Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating Type II, YBCO superconductor, with a relatively high percentage change (0.05-2.1%) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 104 was reported above a stationary (non-rotating) superconductor. In experiments using a sensitive gravimeter, bulk YBCO superconductors were stably levitated in a DC magnetic field and exposed without levitation to low-field strength AC magnetic fields. Changes in observed gravity signals were measured to be less than 2 parts in 108 of the normal gravitational acceleration. Given the high sensitivity of the test, future work will examine variants on the basic magnetic behavior of granular superconductors, with particular focus on quantifying their proposed importance to gravity.

  19. Origin of the resistivity minima in granular superconductors

    International Nuclear Information System (INIS)

    Simanek, E.

    1982-01-01

    The recently observed minima in the temperature dependence of the electrical resistivity of a granular superconductor are explained with use of a percolation model of a disordered granular array, which takes into account the electrostatic charging energy. The thermally activated tunneling of Cooper pairs is shown to play an important role in the interpretation of the experimental data on tin films

  20. Controlled Manipulation of Individual Vortices in a Superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Straver, E.W.J.

    2010-04-05

    We report controlled local manipulation of single vortices by low temperature magnetic force microscope (MFM) in a thin film of superconducting Nb. We are able to position the vortices in arbitrary configurations and to measure the distribution of local depinning forces. This technique opens up new possibilities for the characterization and use of vortices in superconductors.

  1. Observation of magnetooptical effects in several high Tc superconductors

    International Nuclear Information System (INIS)

    Dillon, J.F. Jr; Lyons, K.B.

    1992-01-01

    Recent so called 'anyon' theories of high temperature superconductivity in layer structure materials suggested that at some temperature T TP ≥T c there is a symmetry breaking transition below which these materials may be in either of two distinct states related to each other by time reversal. The study of magneto-optical effects in superconductors reviewed here was undertaken to explore time reversal symmetry of these materials. Using novel technique with rotating λ/2 plate at 525 nm, 'circular dichroism' was observed on reflection from epitaxial films and single crystals of cuprate superconductor with layer structures. The onset of dichroism was at temperatures of ∼ 180K to ∼ 300K. These results appear to support the 'anyon' theories. However, circular dichroism was also seen in films and single crystals of bismuthate superconductors with cubic structure, to which the theories seem inapplicable. In sharp contrast, Spielman et al., at Stanford in a very sensitive experiment at 1060 nm have seen no evidence of non-reciprocal circular birefringence in epitaxial cuprate superconducting films. Weber et al. at Dortmund have recently reported the observation at 633 nm of non-reciprocal magneto-optical effects on single crystals of cuprate superconductors, but none on films. (author). 15 refs., 5 figs

  2. Workshop on accelerator magnet superconductors. Proceedings

    International Nuclear Information System (INIS)

    2004-01-01

    The workshop on accelerator magnet superconductors has gathered 102 registered participants from research laboratories, universities and industry. 8 European companies, active in superconducting materials and cables were present. This workshop has been organized to deal with the status of the world research and development on superconducting materials and cables for high field magnets (B > 10 T). The workshop has also reviewed the status of high temperature superconductors and transmission line cables for potential use in low field superconducting magnets for injectors and beam transfer lines, as well as cables for pulsed magnets that might be used in future hadron colliders or injectors

  3. Workshop on accelerator magnet superconductors. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The workshop on accelerator magnet superconductors has gathered 102 registered participants from research laboratories, universities and industry. 8 European companies, active in superconducting materials and cables were present. This workshop has been organized to deal with the status of the world research and development on superconducting materials and cables for high field magnets (B > 10 T). The workshop has also reviewed the status of high temperature superconductors and transmission line cables for potential use in low field superconducting magnets for injectors and beam transfer lines, as well as cables for pulsed magnets that might be used in future hadron colliders or injectors.

  4. Development of antimicrobial films for microbiological control of packaged salad.

    Science.gov (United States)

    Muriel-Galet, Virginia; Cerisuelo, Josep P; López-Carballo, Gracia; Lara, Marta; Gavara, Rafael; Hernández-Muñoz, Pilar

    2012-07-02

    The aim of the present work was to characterize the antimicrobial efficiency of films consisting of PP/EVOH structures with oregano essential oil and citral. Both substances are known for their antimicrobial activity based on their interaction with the cell membrane. The films developed were used to pack minimally processed salads, combining modified atmosphere technology to extend shelf-life and active packaging technology to reduce possible microbiological risks. The antimicrobial activity of the films against the pathogenic microorganisms Escherichia coli, Salmonella enterica and Listeria monocytogenes and natural microflora was investigated "in vitro" and also on the food itself. The effect of release of the antimicrobial agent on the sensory characteristics of the salad was also studied. The results showed that antimicrobial activity reduced spoilage flora on the salad as well as inhibited the growth of pathogens in contaminated salads. This effect was greater against Gram-negative bacteria. Sensory studies showed that the package that was most effective and most accepted by customers was the one containing 5% oregano essential oil. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Microgravity Processing of Oxide Superconductors

    Science.gov (United States)

    Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus; McCallum, William; Peters, Palmer (Technical Monitor)

    2000-01-01

    The primary goal is to understand the microstructures which develop under the nonequilibrium solidification conditions achieved by melt processing in copper oxide superconductor systems. More specifically, to define the liquidus at the Y- 1:2:3 composition, the Nd-1:2:3 composition, and several intermediate partial substitution points between pure Y-1:2:3 and Nd-1:2:3. A secondary goal has been to understand resultant solidification morphologies and pathways under a variety of experimental conditions and to use this knowledge to better characterize solidification phenomena in these systems.

  6. Electro-physical properties of superconducting ceramic thick film prepared by partial melting method.

    Science.gov (United States)

    Lee, Sang Heon

    2013-05-01

    BiSrCaCuO superconductor thick films were prepared at several curing temperatures, and their electro-physical properties were determined to find an optimum fabrication conditions. Critical temperatures of the superconductors were decreased with increasing melting temperature, which was related to the amount of equilibrium phases of the superconducting materials with temperature. The critical temperature of BiSrCaCuO bulk and thick film superconductors were 107 K and 96 K, respectively. The variation of susceptibility of the superconductor thick film formed at 950 degrees C had multi-step-type curve for 70 G externally applied field, whereas, a superconductor thick film formed at 885 degrees C had a single step-type curve like a bulk BiSrCaCuO ceramic superconductor in the temperature-susceptibility curves. A partial melting at 865 degrees C is one of optimum conditions for making a superconductor thick film with a relatively homogeneous phase.

  7. Charge transport in junctions between d-wave superconductors

    International Nuclear Information System (INIS)

    Barash, Y.S.; Galaktionov, A.V.; Zaikin, A.D.

    1995-01-01

    We develop a microscopic analysis of superconducting and dissipative currents in junctions between superconductors with d-wave symmetry of the order parameter. We study the proximity effect in such superconductors and show that for certain crystal orientations the superconducting order parameter can be essentially suppressed in the vicinity of a nontransparent specularly reflecting boundary. This effect strongly influences the value and the angular dependence of the dc Josephson current j S . At T∼T c it leads to a crossover between j S ∝T c -T and j S ∝(T c -T) 2 respectively for homogeneous and nonhomogeneous distribution of the order parameter in the vicinity of a tunnel junction. We show that at low temperatures the current-phase relation j S (cphi) for superconductor--normal-metal--superconductor junctions and short weak links between d-wave superconductors is essentially nonharmonic and contains a discontinuity at cphi=0. This leads to further interesting features of such systems which can be used for pairing symmetry tests in high-temperature superconductors (HTSC). We also investigated the low-temperature I-V curves of normal-metal--superconductor and superconductor-superconductor tunnel junctions and demonstrated that depending on the junction type and crystal orientation these curves show zero-bias anomalies I∝V 2 , I∝V 2 ln(1/V), and I∝V 3 caused by the gapless behavior of the order parameter in d-wave superconductors. Many of our results agree well with recent experimental findings for HTSC compounds

  8. Theory of the electric current transmission coefficient in the superconductor-insulator-superconductor geometry

    International Nuclear Information System (INIS)

    Navani, R.

    1974-01-01

    Tunneling in the superconductor-insulator-superconductor (S'-I-S) geometry, where the two superconductors are not necessarily the same, is studied theoretically. Two different models of the S'-I-S geometry - which we call the ''initial model'' and the ''improved model'' are discussed. For the initial model the potential barrier is flat. In the improved model, however, the differing material properties of the three regions - S', I, and S - are taken into account in an approximate fashion. In addition, applied, contact, and image potentials in the insulator are included. The solid state material properties that are taken to be different are the effective electronic masses in the three regions and the Fermi energies in the two superconductors. The quasiparticle wave functions in the S', I, and S regions are determined for both models as solutions to the Bogoliubov-de Gennes equations. The electric current transmission coefficients (also the reflection coefficient for the initial model) are derived and their behavior is extensively analyzed. Their forms in the thick barrier limit - where L greater than or approximately equal to 5 A - are related to the BCS densities of states. The tunneling current density is found to depend strongly on the tunneling angle. A relation between the angular position of the tunneling current peak and the barrier thickness is given. Finally, it is shown that the choice of insulator material effects the tunneling current, and the effect is greater the thicker the insulating film

  9. Starch films from a novel (Pachyrhizus ahipa) and conventional sources: Development and characterization

    International Nuclear Information System (INIS)

    López, Olivia V.; García, María A.

    2012-01-01

    Biodegradable films from ahipa, cassava and corn native starches were developed by casting method and their physicochemical, mechanical and barrier properties were analyzed taking into account the different starch botanical sources. Filmogenic suspensions were prepared; their rheological behaviors were studied and all of them exhibited film-forming ability. However, mechanical assays demonstrated that unplasticized films were too rigid, limiting their technological applications. Thus, 1.5% w/w of glycerol as plasticizer was added to filmogenic suspensions and film flexibility and extensibility were improved, this effect was more significant for ahipa and cassava starch films. Furthermore, thickness, moisture content and water solubility of the developed films were increased when plasticizer was incorporated. Glycerol addition reduced film water vapor permeability and the lowest reduction corresponded to cassava starch films due to the high viscosity of its filmogenic suspensions. Plasticized starch films resulted to be UV radiation barriers; ahipa starch films had the lowest light absorption capacity and higher transparency than cassava and corn starch films. Dynamic-mechanical analysis indicated that plasticized films were partially miscible systems exhibiting two relaxations, one attributed to the starch-rich phase and the other to the glycerol-rich one. Likewise, it could be demonstrated that glycerol exerted a major plasticizing effect on ahipa starch matrixes. Highlights: ► Ahipa, cassava and corn starch films were developed by casting method. ► Glycerol effect on film mechanical behavior was major for tuberous starch films. ► Ahipa starch films resulted to be more transparent with lower UV absorption capacity. ► Plasticized films were partially miscible systems: with a glycerol-rich and a starch-rich phase. ► Glycerol exerted a major plasticizing effect on ahipa starch films.

  10. Superfluid response in heavy fermion superconductors

    Science.gov (United States)

    Zhong, Yin; Zhang, Lan; Shao, Can; Luo, Hong-Gang

    2017-10-01

    Motivated by a recent London penetration depth measurement [H. Kim, et al., Phys. Rev. Lett. 114, 027003 (2015)] and novel composite pairing scenario [O. Erten, R. Flint, and P. Coleman, Phys. Rev. Lett. 114, 027002 (2015)] of the Yb-doped heavy fermion superconductor CeCoIn5, we revisit the issue of superfluid response in the microscopic heavy fermion lattice model. However, from the literature, an explicit expression for the superfluid response function in heavy fermion superconductors is rare. In this paper, we investigate the superfluid density response function in the celebrated Kondo-Heisenberg model. To be specific, we derive the corresponding formalism from an effective fermionic large- N mean-field pairing Hamiltonian whose pairing interaction is assumed to originate from the effective local antiferromagnetic exchange interaction. Interestingly, we find that the physically correct, temperature-dependent superfluid density formula can only be obtained if the external electromagnetic field is directly coupled to the heavy fermion quasi-particle rather than the bare conduction electron or local moment. Such a unique feature emphasizes the key role of the Kondo-screening-renormalized heavy quasi-particle for low-temperature/energy thermodynamics and transport behaviors. As an important application, the theoretical result is compared to an experimental measurement in heavy fermion superconductors CeCoIn5 and Yb-doped Ce1- x Yb x CoIn5 with fairly good agreement and the transition of the pairing symmetry in the latter material is explained as a simple doping effect. In addition, the requisite formalism for the commonly encountered nonmagnetic impurity and non-local electrodynamic effect are developed. Inspired by the success in explaining classic 115-series heavy fermion superconductors, we expect the present theory will be applied to understand other heavy fermion superconductors such as CeCu2Si2 and more generic multi-band superconductors.

  11. Reversal film development for streamer chamber track photographs

    International Nuclear Information System (INIS)

    Bahr, J.

    1982-01-01

    It is the aim of this work to create a method of photographic development specially adapted to streamer image recording, i.e., with high sensitivity, only two signal levels, low dependence of the track signal on image intensity having a great jitter and noise suppression. The method has to be suitable for machine development of high speed films. A reversal photographic development was used to realize these demands, whereby strong fogging in the first step negative development and a solving process for silver bromide after blackening are specially introduced process stages. This results in a step-function shaped characteristic curve with small transition region having only two signal levels, i. e., independence of streamer image density, good resolution, fine grain, suppression of flares and low noise in the signal of the clear streamer images

  12. Effect of disorder on S-wave superconductors

    International Nuclear Information System (INIS)

    Ghosal, Amit; Randeria, Mohit; Trivedi, Nandini

    1997-01-01

    Experiment on conventional s-wave superconducting thin films have found a strong suppression of T c , with a subsequent transition from a superconductor (SC) to an insulator (I) with increasing disorder. Anderson proposed that even in the presence of disorder the Cooper pairs can be formed by pairing the time-reversed exact eigenstates of the non interacting disordered problem. Hence he argued that T c and the thermodynamic properties should be unaffected by disorder (Anderson's theorem). This is however valid for extremely small disorder. The aim here is to calculate the properties of a superconductor at high disorder, close to the SC-I transition

  13. Classical spins in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shiba, H [Tokyo Univ.; Maki, K

    1968-08-01

    It is shown that there exists a localized excited state in the energy gap in a superconductor with a classical spin. At finite concentration localized excited states around classical spins form an impurity band. The process of growth of the impurity band and its effects on observable quantities are investigated.

  14. Irradiation damage in superconductors

    International Nuclear Information System (INIS)

    Quere, Y.

    1989-01-01

    Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs

  15. Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils.

    Science.gov (United States)

    Cao, Thi Luyen; Yang, So-Young; Song, Kyung Bin

    2018-01-03

    In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry.

  16. Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils

    Science.gov (United States)

    Cao, Thi Luyen; Yang, So-Young; Song, Kyung Bin

    2018-01-01

    In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry. PMID:29301339

  17. Development of Oral Fast-Disintegrating Levothyroxine Films for ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... The films were evaluated for disintegration time, in vitro drug release, physical appearance, thickness, ... film is suitable for levothyroxine in the management of hypothyroidism in pediatrics.

  18. High-Tc superconductor applications

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    There has been much speculation about new products and business opportunities which high-Tc superconductors might make possible. However, with the exception of one Japanese survey, there have not been any recognized forecasts suggesting a timeframe and relative economic impact for proposed high-Tc products. The purpose of this survey is to provide definitive projections of the timetable for high-Tc product development, based on the combined forecasts of the leading U.S. superconductivity experts. The FTS panel of experts on high-Tc superconductor applications, representing both business and research, forecast the commercialization and economic impact for 28 classes of electronic, magnetic, communications, instrumentation, transportation, industrial, and power generation products. In most cases, forecasts predict the occurrence of developments within a 90% statistical confidence limit of 2-to-3 years. The report provides background information on the 28 application areas, as well as other information useful for strategic planners. The panel also forecast high-Tc research spending, markets, and international competitiveness, and provide insight into how the industry will evolve

  19. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  20. Application of superconductors to motors, generators, and transmission lines

    International Nuclear Information System (INIS)

    Kirtley, J.L.

    1989-01-01

    Superconductors are of interest to the designers of electric power equipment because they can carry current without loss, currents that are large enough to make very intense magnetic fields. This means that superconductors, used in suitable applications, can make electric power equipment smaller, lighter, more efficient, and perhaps with better dynamic response. Two specific applications are considered here: electric machinery (motors and generators) and transmission lines. The so-called high-T c superconductors will have beneficial impact on motors, generators, and transmission lines only if conductors with sufficient mechanical properties and current-carrying capabilities can be developed

  1. Holographic superconductor in the analytic hairy black hole

    International Nuclear Information System (INIS)

    Myung, Yun Soo; Park, Chanyong

    2011-01-01

    We study the charged black hole of hyperbolic horizon with scalar hair (charged Martinez-Troncoso-Zanelli: CMTZ black hole) as a model of analytic hairy black hole for holographic superconductor. For this purpose, we investigate the second order phase transition between CMTZ and hyperbolic Reissner-Nordstroem-AdS (HRNAdS) black holes. However, this transition unlikely occurs. As an analytic treatment for holographic superconductor, we develop superconductor in the bulk and superfluidity on the boundary using the CMTZ black hole below the critical temperature. The presence of charge destroys the condensates around the zero temperature, which is in accord with the thermodynamic analysis of the CMTZ black hole.

  2. Fractional Josephson vortices in two-gap superconductor long Josephson junctions

    Science.gov (United States)

    Kim, Ju

    2014-03-01

    We investigated the phase dynamics of long Josephson junctions (LJJ) with two-gap superconductors in the broken time reversal symmetry state. In this LJJ, spatial phase textures (i-solitons) can be excited due to the presence of two condensates and the interband Joesphson effect between them. The presence of a spatial phase texture in each superconductor layer leads to a spatial variation of the critical current density between the superconductor layers. We find that this spatial dependence of the crtitical current density can self-generate magnetic flux in the insulator layer, resulting in Josephson vortices with fractional flux quanta. Similar to the situation in a YBa2 Cu3O7 - x superconductor film grain boundary, the fractionalization of a Josephson vortex arises as a response to either periodic or random excitation of i-solitions. This suggests that magnetic flux measurements may be used to probe i-soliton excitations in multi-gap superconductor LJJs.

  3. Critical de Broglie wavelength in superconductors

    Science.gov (United States)

    Talantsev, E. F.

    2018-03-01

    There are growing numbers of experimental evidences that the self-field critical currents, Jc(sf,T), are a new instructive tool to investigate fundamental properties of superconductors ranging from atomically thin films [M. Liao et al., Nat. Phys. 6 (2018), https://doi.org/10.1038/s41567-017-0031-6; E. F. Talantsev et al., 2D Mater. 4 (2017) 025072; A. Fete et al., Appl. Phys. Lett. 109 (2016) 192601] to millimeter-scale samples [E. F. Talantsev et al., Sci. Rep. 7 (2017) 10010]. The basic empirical equation which quantitatively accurately described experimental Jc(sf,T) was proposed by Talantsev and Tallon [Nat. Commun. 6 (2015) 7820] and it was the relevant critical field (i.e. thermodynamic field, Bc, for type-I and lower critical field, Bc1, for type-II superconductors) divided by the London penetration depth, λL. In this paper, we report new findings relating to this empirical equation. It is that the critical wavelength of the de Broglie wave, λdB,c, of the superconducting charge carrier which within a numerical pre-factor is equal to the largest of two characteristic lengths of Ginzburg-Landau theory, i.e. the coherence length, ξ, for type-I superconductors or the London penetration depth, λL, for type-II superconductors. We also formulate a microscopic criterion for the onset of dissipative transport current flow: ps ṡ 2ṡλL ln(1+2ṡ(λL ξ )) ≥ 1 2 ṡ ( h 2π), where ps is the charge carrier momentum, h is Planck’s constant and the inequality sign “ <” is reserved for the dissipation-free flow.

  4. Development of CIGS2 thin film solar cells

    International Nuclear Information System (INIS)

    Dhere, Neelkanth G.; Gade, Vivek S.; Kadam, Ankur A.; Jahagirdar, Anant H.; Kulkarni, Sachin S.; Bet, Sachin M.

    2005-01-01

    Research and development of CuIn 1-x Ga x Se 2-y S y (CIGSS) thin-film solar cells on ultralightweight flexible metallic foil substrates is being carried out at FSEC PV Materials Lab for space applications. Earlier, the substrate size was limited to 3 cm x 2.5 cm. Large-area sputtering systems and scrubber for hydrogen selenide and sulfide have been designed and constructed for preparation of CIGSS thin-films on large (15 cm x 10 cm) substrates. A selenization/sulfurization furnace donated by Shell (formerly Siemens) Solar has also been refurbished and upgraded. The sputtering target assembly design was modified for proper clamping of targets and effective cooling. A new design of the magnetic assembly for large-area magnetron sputtering sources was implemented so as to achieve uniform deposition on large area. Lightweight stainless steel foil and ultralightweight titanium foil substrates were utilized to increase the specific power of solar cells. Sol-gel derived SiO 2 layers were coated on titanium foil by dip coating method. Deposition parameters for the preparation of molybdenum back contact layers were optimized so as to minimize the residual stress as well as reaction with H 2 S. Presently large (15 cm x 10 cm) CuIn 1-x Ga x S 2 (CIGS2) thin film solar cells are being prepared on Mo-coated titanium and stainless steel foil by sulfurization of CuGa/In metallic precursors in diluted Ar:H 2 S(4%). Heterojunction partner CdS layers are deposited by chemical bath deposition. The regeneration sequence of ZnO/ZnO:Al targets was optimized for obtaining consistently good-quality, transparent and conducting ZnO/ZnO:Al bilayer by RF magnetron-sputter deposition. Excellent facilities at FSEC PV Materials Lab are one of its kinds and could serve as a nucleus of a small pilot plant for CIGSS thin film solar cell fabrication

  5. Superconductor bearings, flywheels and transportation

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Rothfeld, R; Riedel, T; Goebel, B; Wippich, D; Schirrmeister, P

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN 2 . More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  6. Modified entropic gravitation in superconductors

    International Nuclear Information System (INIS)

    Matos, Clovis Jacinto de

    2012-01-01

    Verlinde recently developed a theoretical account of gravitation in terms of an entropic force. The central element in Verlinde’s derivation is information and its relation with entropy through the holographic principle. The application of this approach to the case of superconductors requires to take into account that information associated with superconductor’s quantum vacuum energy is not stored on Planck size surface elements, but in four volume cells with Planck-Einstein size. This has profound consequences on the type of gravitational force generated by the quantum vacuum condensate in superconductors, which is closely related with the cosmological repulsive acceleration responsible for the accelerated expansion of the Universe. Remarkably this new gravitational type force depends on the level of breaking of the weak equivalence principle for cooper pairs in a given superconducting material, which was previously derived by the author starting from similar principles. It is also shown that this new gravitational force can be interpreted as a surface force. The experimental detection of this new repulsive gravitational-type force appears to be challenging.

  7. Iron pnictide superconductors

    International Nuclear Information System (INIS)

    Tegel, Marcus Christian

    2011-01-01

    The scope of this dissertation therefore has not only been the synthesis of various new superconducting and non-superconducting iron pnictides of several structural families but also their in-depth crystallographic and physical characterisation. In Chapters 3 - 6, the family of the ZrCuSiAs-type (1111) compounds is subject of discussion. The solid solution series La(Co x Fe 1-x )PO is analysed regarding magnetic and superconducting properties and the new compounds EuMnPF and REZnPO, as well as the new superconductor parent compound SrFeAsF are presented. Chapters 7 - 9 are dedicated to the new iron arsenide superconductors of the ThCr 2 Si 2 -type (122 family). Therein, also the discovery of the first superconductor in this structural family, Ba 0.6 K 0.4 Fe 2 As 2 , is unveiled. A detailed examination of the complete solid solution series (Ba 1-x K x )Fe 2 As 2 is presented. Moreover, the crystallographic phase transitions of the closely related compounds SrFe 2 As 2 and EuFe 2 As 2 are characterised and the superconductors Sr 1-x K x Fe 2 As 2 and Ca 1-x Na x Fe 2 As 2 are examined for magnetic and phononic excitations. In Chapter 10, the redetermined crystal structure of the superconductor Fe(Se 1-x Te x ) (11-type) is presented from a chemist's point of view. Chapters 11 - 14 look into the superconducting and non-superconducting iron arsenides of more complex structural families (32522-type and 21311-type). Therein, crystallographic and magnetic details of Sr 3 Sc 2 O 5 Fe 2 As 2 are presented and Ba 2 ScO 3 FeAs and Sr 2 CrO 3 FeAs, the first two members of the new 21311-type are portrayed. Sr 2 CrO 3 FeAs is looked at in close detail with various methods, so e.g. the spin structure of the magnetically ordered compound is solved and a possible reason for the absence of superconductivity in this compound is given. Finally, the superconductor Sr 2 VO 3 FeAs is scrutinised and necessary prerequisites for superconductivity in this compound are suggested. (orig.)

  8. "Fluctuoscopy" of Superconductors

    Science.gov (United States)

    Varlamov, A. A.

    Study of fluctuation phenomena in superconductors (SCs) is the subject of great fundamental and practical importance. Understanding of their physics allowed to clear up the fundamental properties of SC state. Being predicted in 1968, one of the fluctuation effects, namely paraconductivity, was experimentally observed almost simultaneously. Since this time, fluctuations became a noticeable part of research in the field of superconductivity, and a variety of fluctuation effects have been discovered. The new wave of interest to fluctuations (FL) in superconductors was generated by the discovery of cuprate oxide superconductors (high-temperature superconductors, HTS), where, due to extremely short coherence length and low effective dimensionality of the electron system, superconductive fluctuations manifest themselves in a wide range of temperatures. Moreover, anomalous properties of the normal state of HTS were attributed by many theorists to strong FL in these systems. Being studied in the framework of the phenomenological Ginzburg-Landau theory and, more extensively, in diagrammatic microscopic approach, SC FLs side by side with other quantum corrections (weak localization, etc.) became a new tool for investigation and characterization of such new systems as HTS, disordered electron systems, granular metals, Josephson structures, artificial super-lattices, etc. The characteristic feature of SC FL is their strong dependence on temperature and magnetic fields in the vicinity of phase transition. This allows one to definitely separate the fluctuation effects from other contributions and to use them as the source of information about the microscopic parameters of a material. By their origin, SC FLs are very sensitive to relaxation processes, which break phase coherence. This allows using them for versatile characterization of SC. Today, one can speak about the " fluctuoscopy" of superconductive systems. In review, we present the qualitative picture both of thermodynamic

  9. Measuring condensate fraction in superconductors

    International Nuclear Information System (INIS)

    Chakravarty, Sudip; Kee, Hae-Young

    2000-01-01

    An analysis of off-diagonal long-range order in superconductors shows that the spin-spin correlation function is significantly influenced by the order if the order parameter is anisotropic on a microscopic scale. Thus, magnetic neutron scattering can provide a direct measurement of the condensate fraction of a superconductor. It is also argued that recent measurements in high-temperature superconductors come very close to achieving this goal. (c) 2000 The American Physical Society

  10. Processing of Mixed Oxide Superconductors

    Science.gov (United States)

    1990-07-01

    rapid changes world wide a major research centre on high Tc superconductors was awarded to Cambridge which involved moving the work and people to a...reports and paper is in the appendices. Separation Ceramic superconductors tend to be mixtures of phases, especially when first discovered. It would...properties of the superconducting state will in principle allow superconducting material to be levitated from the non superconductor and several designs

  11. Creation of the best performance high-$T_{c}$ superconductor based on Cu-1234

    CERN Document Server

    Ihara, H; Iyo, A; Kito, H; Terada, N; Tokumoto, M; Ishida, K; Sekita, Y; Yamamoto, H; Hayashi, H; Khan, N A; Sundaresan, A; Nie, J; Harashima, E; Ishiura, Y; Tateai, F; Kawamura, M

    1999-01-01

    The purpose of this project is to create the best performance superconductor on the basis of our original Cu-1234 (CuBa/sub 2/Ca /sub 3/Cu/sub 4/O/sub 12-y/) superconductor. Its best performance superconductor will be realized by the modification of superconducting wave function (MSWF) and application of new preparation techniques of thin films. The MSWF leads to the enhancement of coherence length along the c-axis and transformation from d-wave to (d+is)-wave, and then low superconducting anisotropy. The thin film techniques are APE (amorphous phase epitaxy) method and SAE (self assembling epitaxy) method by using a structure stabilizer such as Tl. The best superconductor with long coherence length, low anisotropy, high T/sub c/, high J/sub c/ and high H/sub irr/ will be realized for wire and Josephson junctions and microwave device application at 77 K. (16 refs).

  12. High Temperature Superconductor Resonator Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — High Temperature Superconductor (HTS) infrared detectors were studied for years but never matured sufficiently for infusion into instruments. Several recent...

  13. A high temperature superconductor tape RF receiver coil for a low field magnetic resonance imaging system

    International Nuclear Information System (INIS)

    Cheng, M C; Yan, B P; Lee, K H; Ma, Q Y; Yang, E S

    2005-01-01

    High temperature superconductor (HTS) thin films have been applied in making a low loss RF receiver coil for improving magnetic resonance imaging image quality. However, the application of these coils is severely limited by their limited field of view (FOV). Stringent fabrication environment requirements and high cost are further limitations. In this paper, we propose a simpler method for designing and fabricating HTS coils. Using industrial silver alloy sheathed Bi (2-x) Pb x Sr 2 Ca 2 Cu 3 O 10 (Bi-2223) HTS tapes, a five-inch single-turn HTS solenoid coil has been developed, and human wrist images have been acquired with this coil. The HTS tape coil has demonstrated an enhanced FOV over a six-inch YBCO thin film surface coil at 77 K with comparable signal-to-noise ratio

  14. Superconductor-insulator-normal-conductor-insulator-superconductor (Nb/Al{sub x}O{sub y}/Al/Al{sub x}O{sub y}/Nb) process development for integrated circuit applications

    Energy Technology Data Exchange (ETDEWEB)

    Balashov, D.; Buchholz, F.M.; Schulze, H.; Khabipov, M.I.; Kessel, W.; Niemeyer, J. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    1998-12-01

    The paper reports on recent developments in a new technology process in LTS implementation to fabricate intrinsically shunted tunnel junctions. The process has been realized in SINIS Nb/Al{sub x}O{sub y}/Al/Al{sub x}O{sub y}/Nb multilayer thin-film technology. In various test series, circuits containing a large variety of single junctions and junction arrays of different contact areas and sizes were fabricated and measured. By variation of the oxidation parameters the fabrication process has been optimized for application in integrated circuits operating in RSFQ impulse logic. The junction parameter values realized for the critical current density j{sub c} range to up to about j{sub c} = 1000 A cm{sup -2}, those for the characteristic voltage V{sub c} to up to about V{sub c} = 230 {mu}V. The junctions show nearly non-hysteretic current-voltage characteristics; the intra-wafer parameter spread is below 10%. The junctions realized fulfil the requirements imposed for digital RSFQ circuit operation at clock frequencies in the lower GHz frequency range. (author)

  15. Neutron Depolarization in Superconductors

    Science.gov (United States)

    Zhuchenko, N. K.

    1995-04-01

    The dependences of neutron depolarization on applied magnetic field are deduced along the magnetization hysteresis loop in terms of the Bean model of the critical state. The depolarization in uniaxial superconductors with the reversible magnetization, including uniaxial magnetic superconductors, is also considered. A strong depolarization is expected if the neutrons travel along the vortex lines. On calcule la dépendance en champ magnétique de la dépolarisation des neutrons le long du cycle d'hystérésis en termes du modèle critique de Bean. On considère aussi la dépolarisation dans les supraconducteurs uniaxiaux en fonction de l'aimantation réversible, y compris pour les supraconducteurs magnétiques. On attend une forte dépolarisation si les neutrons se propagent le long des vortex.

  16. Vortices and nanostructured superconductors

    CERN Document Server

    2017-01-01

    This book provides expert coverage of modern and novel aspects of the study of vortex matter, dynamics, and pinning in nanostructured and multi-component superconductors. Vortex matter in superconducting materials is a field of enormous beauty and intellectual challenge, which began with the theoretical prediction of vortices by A. Abrikosov (Nobel Laureate). Vortices, vortex dynamics, and pinning are key features in many of today’s human endeavors: from the huge superconducting accelerating magnets and detectors at the Large Hadron Collider at CERN, which opened new windows of knowledge on the universe, to the tiny superconducting transceivers using Rapid Single Flux Quanta, which have opened a revolutionary means of communication. In recent years, two new features have added to the intrinsic beauty and complexity of the subject: nanostructured/nanoengineered superconductors, and the discovery of a range of new materials showing multi-component (multi-gap) superconductivity. In this book, leading researche...

  17. Radiation behavior of superconductors

    International Nuclear Information System (INIS)

    Scanlan, R.M.; Raymond, E.L.

    1979-01-01

    High energy neutron irradiations have been performed on Nb 3 Sn superconductors to assess their behavior in a fusion reactor environment. Irradiations were performed at 4.2 K and property measurements were made without warming the samples. The critical current I/sub c/ increased with irradiation to a level about 50% above the unirradiated value at the highest fluences reached in our experiments. These results are compared with the results of other low temperature irradiations of Nb 3 Sn

  18. Strongly disordered superconductors

    International Nuclear Information System (INIS)

    Muttalib, K.A.

    1982-01-01

    We examine some universal effects of strong non-magnetic disorder on the electron-phonon and electron-electron interactions in a superconductor. In particular we explicitly take into account the effect of slow diffusion of electrons in a disordered medium by working in an exact impurity eigenstate representation. We find that the normal diffusion of electrons characterized by a constant diffusion coefficient does not lead to any significant correction to the electron-phonon or the effective electron-electron interactions in a superconductor. We then consider sufficiently strong disorder where Anderson localization of electrons becomes important and determine the effect of localization on the electron-electron interactions. We find that due to localization, the diffusion of electrons becomes anomalous in the sense that the diffusion coefficient becomes scale dependent. This results in an increase in the effective electron-electron interaction with increasing disorder. We propose that this provides a natural explanation for the unusual sensitivity of the transition temperature T/sub c/ of the high T/sub c/ superconductors (T/sub c/ > 10 0 K) to damage effects

  19. Developing strategies to promote the Iranian international film market

    Directory of Open Access Journals (Sweden)

    Mahmood Mohammadian

    2012-04-01

    Full Text Available International film market of Iran (IFM is one of the most important presenters of different films and television programs to be sold in the world market especially in Middle East. The primary purpose of this paper is to investigate different methods to promote this market. The study uses a questionnaire and distributes it among buyers and sales agents of IFM. The results of hypothetic tests prove that the socio-cultural factors are the most important reasons for the participants. Another important criterion promoting sales of movies is different awards from various movie festivals dedicated to moviemakers. The opening date and place of market, publication and publicity are other important criteria influencing sales of movies. The paper illustrates film-marketing mix for film marketers. Indicators, which are important for participants in international film festivals, are also illustrated for international film market holders.

  20. Enhancement of critical temperature in fractal metamaterial superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Smolyaninov, Igor I., E-mail: smoly@umd.edu [Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742 (United States); Smolyaninova, Vera N. [Department of Physics Astronomy and Geosciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)

    2017-04-15

    Fractal metamaterial superconductor geometry has been suggested and analyzed based on the recently developed theoretical description of critical temperature increase in epsilon near zero (ENZ) metamaterial superconductors. Considerable enhancement of critical temperature has been predicted in such materials due to appearance of large number of additional poles in the inverse dielectric response function of the fractal. Our results agree with the recent observation (Fratini et al. Nature 466, 841 (2010)) that fractal defect structure promotes superconductivity.

  1. The critical current of superconductors: an historical review

    International Nuclear Information System (INIS)

    Dew-Hughes, D.

    2001-01-01

    The most important practical characteristic of a superconductor is its critical current density. This article traces the history, both of the experimental discoveries and of the development of the theoretical ideas that have lead to the understanding of those factors that control critical current densities. These include Silsbee's hypothesis, the Meissner effect, London, Ginsburg-Landau and Abrikosov theories, flux pinning and the critical state, and the control of texture in high temperature superconductors

  2. Manufacturing and quality assurance for the MFTF superconductor core

    International Nuclear Information System (INIS)

    Scanlan, R.M.; Johnston, J.E.; Waide, P.A.; Zeitlin, B.A.; Smith, G.B.; Nelson, C.T.

    1979-01-01

    A total of 55,000 m of multifilamentary Nb-Ti superconductor in minimum lengths of 380 m are required for the Mirror Fusion Test Facility. This conductor is a large cross-section monolith and, as such, has presented several new manufacturing challenges. In addition, a monolith requires more stringent quality assurance procedures than braids or cables. This paper describes the manufacturing steps and the quality assurance program which have been developed for the MFTF superconductor core

  3. Effective Ginzburg–Landau free energy functional for multi-band isotropic superconductors

    International Nuclear Information System (INIS)

    Grigorishin, Konstantin V.

    2016-01-01

    Highlights: • The intergradient coupling of order parameters in a two-band superconductor plays important role and cannot be neglected. • A two-band superconductor must be characterized with a single coherence length and a single Ginzburg–Landau parameter. • Type-1.5 superconductors are impossible. • The free energy functional for a multi-band superconductor can be reduced to the effective single-band Ginzburg–Landau functional. - Abstract: It has been shown that interband mixing of gradients of two order parameters (drag effect) in an isotropic bulk two-band superconductor plays important role – such a quantity of the intergradients coupling exists that the two-band superconductor is characterized with a single coherence length and a single Ginzburg–Landau (GL) parameter. Other quantities or neglecting of the drag effect lead to existence of two coherence lengths and dynamical instability due to violation of the phase relations between the order parameters. Thus so-called type-1.5 superconductors are impossible. An approximate method for solving of set of GL equations for a multi-band superconductor has been developed: using the result about the drag effect it has been shown that the free-energy functional for a multi-band superconductor can be reduced to the GL functional for an effective single-band superconductor.

  4. High Tc superconductors at microwave frequencies

    International Nuclear Information System (INIS)

    Gruener, G.

    1991-01-01

    The author discusses various experiments conducted in the micro- and millimeter wave spectral range on thin film and single crystal specimens of the high temperature oxide superconductors. For high quality film the surface resistance R s is, except at low temperatures, due to thermally excited carriers, with extrinsic effects playing only a secondary role. Because of the low loss various passive microwave components, such as resonators, delay lines and filters, with performance far superior to those made of normal metals can be fabricated. The conductivity measured at millimeter wave frequencies displays a peak below T c . Whether this is due to coherence factors or due to the change of the relaxation rate when the materials enter the superconducting state remains to be seen

  5. High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

    Energy Technology Data Exchange (ETDEWEB)

    Selvamanickam, V; Gharahcheshmeh, MH; Xu, A; Galstyan, E; Delgado, L; Cantoni, C

    2015-01-19

    REBa2Cu3Ox ((REBCO), RE = rare earth) superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50K and fields of 2-30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J(c)) above 20 MA/cm(2) at 30 K, 3 T in heavily doped (25 mol.% Zr-added) (Gd,Y)Ba2Cu3Ox superconductor tapes, which is more than three times higher than the J(c) typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m(3) have also been attained at 20 K. A composition map of lift factor in J(c) (ratio of J(c) at 30 K, 3 T to the J(c) at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO3 (BZO) nanocolumn defect density of nearly 7 x 10(11) cm(-2) as well as 2-3 nm sized particles rich in Cu and Zr have been found in the high J(c) films. (C) 2015 AIP Publishing LLC.

  6. Controlling the flux dynamics in superconductors by nanostructured magnetic arrays

    Science.gov (United States)

    Kapra, Andrey

    In this thesis we investigate theoretically how the critical current jc of nano-engineered mesoscopic superconducting film can be improved and how one can control the dynamics of the magnetic flux, e.g., the transition from flux-pinned to flux-flow regime, using arrays of magnetic nanostructures. In particularly we investigate: (1) Vortex transport phenomena in superconductors with deposited ferromagnetic structures on top, and the influence of the sample geometry on the critical parameters and on the vortex configurations. Changing geometry of the magnetic bars and magnetization of the bars will affect the critical current jc of the superconducting film. Such nanostructured ferromagnets strongly alter the vortex structure in its neighborhood. The influence of geometry, position and magnetization of the ferromagnet (single bar or regular lattice of the bars) on the critical parameters of the superconductor is investigated. (2) Effect of flux confinement in narrow superconducting channels with zigzag-shaped banks: the flux motion is confined in the transverse (perpendicular) direction of a diamond-cell-shape channel. The matching effect for the magnetic flux is found in the system relevantless of boundary condition. We discuss the dynamics of vortices in the samples and vortex pattern formation in the channel. We show how the inclusion of higher-Tc superconductor into the sample can lead to enhanced properties of the system. By adding an external driving force, we study the vortex dynamics. The different dynamic regimes are discussed. They allowed an effective control of magnetic flux in superconductors.

  7. Research and development of stabilized multifilamentary Nb3 Sn superconductors. Technical report for the period, 12 September 1976 through 30 September 1977

    International Nuclear Information System (INIS)

    Ormand, F.T.

    1977-01-01

    An investigation of tensile properties of multifilamentary Nb 3 Sn superconductors indicated that composites containing less than 12.5 volume percent (v/o) Nb 3 Sn were usually ductile. Composites containing more than 12.5 v/o Nb 3 Sn were brittle

  8. High point for CERN and high-temperature superconductors

    CERN Multimedia

    2007-01-01

    Amalia Ballarino is named the Superconductor Industry Person of the year 2006. Amalia Ballarino showing a tape of high-superconducting material used for the LHC current leads.The CERN project leader for the high-temperature superconducting current leads for the LHC, Amalia Ballarino, has received the award for "Superconductor Industry Person of the Year". This award, the most prestigious international award in the development and commercialization of superconductors, is presented by the leading industry newsletter "Superconductor Week". Amalia Ballarino was selected from dozens of nominations from around the world by a panel of recognized leading experts in superconductivity. "It is a great honour for me," says Amalia Ballarino. "It has been many years of hard work, and it’s a great satisfaction to see that the work has been completed successfully." Amalia Ballarino has been working on high-temperature superconducting materials sin...

  9. Development of techniques for fabrication of film probe sensor assembly

    International Nuclear Information System (INIS)

    Moorhead, A.J.

    1982-10-01

    Pulsed laser welding and brazing techniques were developed for fabrication of sensors designed to measure liquid film properties in out-of-reactor safety tests that simulate a loss-of-coolant accident in a pressurized-water nuclear reactor. These sensors were made possible by a unique ceramic-to-metal seal system based on a cermet insulator and a brazing filler metal, both developed at ORNL. This seal system was shown to resist steam to an exposure of at least 100 h at 700 0 C (1292 0 F) and to resist repetitive thermal transients of 300 0 C/s (540 0 F). Procedures were also developed for induction brazing the instrumentation cables to a stainless steel end cap and for laser welding this component to the brazed sensor body itself. Cable end seals and sensor bodies fabricated with these designs and techniques maintained excellent helium leaktightness ( -6 cm 3 /s) after 20 severe thermal shock tests from 500 0 C air into water at 80 0 C

  10. Development of Cutaneous Bioadhesive Ureasil-Polyether Hybrid Films

    Directory of Open Access Journals (Sweden)

    João Augusto Oshiro Junior

    2015-01-01

    Full Text Available The hydrolysis and condensation reactions involved in synthesis of ureasil-polyether films influence the film formation time and the number of chemical groups able to form hydrogen bonds, responsible for the bioadhesion, with the biological substrate. The objective of this work was to study the influence of the use of an acid catalyst (hydrochloric acid and a basic catalyst (ammonium fluoride in the hydrolysis and condensation reactions on the time formation and bioadhesion of ureasil-polyether films. The toxicity of the films was evaluated. The MTT assay has shown cell viability of human skin keratinocytes higher than 70% of all analyzed materials suggesting low cytotoxicity. The bioadhesion of the films is strongly dependent on the viscosity and hydrophilic/hydrophobic balance of the polyether chains used to synthetize the hybrid molecules. The use of acid catalyst promotes the formation of less viscous films with higher bioadhesion. The hybrids formed by more hydrophilic PEO chains are more bioadherent, since they can interact more efficiently with the water present in the stratum corneum increasing the bioadhesion. Due to their low toxicity and high bioadhesion, the ureasil-PEO films obtained by using HCl as catalyst agent are good candidates for application to the skin as bioadhesive films.

  11. Testability issues in Superconductor Electronics

    NARCIS (Netherlands)

    Kerkhoff, Hans G.; Arun, Arun J.

    2004-01-01

    An emerging technology for solutions in high-end applications in computing and telecommunication is superconductor electronics. A system-level study has been carried out to verify the feasibility of DfT in superconductor electronics. In this paper, we present how this can be realized to monitor

  12. Method for preparation of superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Barber, A.C.; McDougall, I.L.

    1975-07-10

    The invention deals with a method to prepare a superconductor consisting of a superconducting compound of at least two elements. It especially deals with superconductors which surround a superconducting intermetallic compounds of at least two elements, examples of which are Nb/sub 2/Sn and Nb/sub 3/Al.

  13. Nonmagnetic impurities in magnetic superconductors

    International Nuclear Information System (INIS)

    Mineev, V.P.

    1989-01-01

    The magnetization and magnetic field arising around the nonmagnetic impurity in magnetic superconductor with triplet pairing are found. The relationship of these results with the data of recent (gm)sR experiments in heavy fermionic superconductor U 1 - x Th x Be 13 is presented

  14. Commercial Development Of Ovonic Thin Film Solar Cells

    Science.gov (United States)

    Ovshinsky, Stanford R.

    1983-09-01

    One square foot Ovonic amorphous photovoltaic devices are already in commercial production and are manufactured through a continuous web process. The next levels of commercialization required to achieve a large-volume power market will be discussed, and the device specifications correlated with the chemical and electronic properties of the materials that we are developing to achieve even higher efficiencies. It has been long considered a utopian dream to harness the energy of the sun to create electricity that would be competitive in cost to that produced from the conventional sources of energy such as oil, gas, and uranium. The impact on our society of stand-alone power generators without moving parts using the continually available, ubiquitous energy of the sun could certainly lead to a new age with consequences comparable to the first introduction of electricity which greatly accelerated the Industrial Revolution. Low cost, nonpolluting energy not dependent upon or limited by transmission costs could again make DC electricity a realistic option. The relatively young field of photovoltaics suffers from certain dogmas that are just now being questioned. For example, it is thought by many that solar cells utilizing crys-talline materials have inherently higher efficiencies than those using amorphous materials, and that somehow crystalline solar cells, whether fabricated from single crystals or polycrystalline material, in round or rectangular geometries, grown from the melt or by a rib-bon process, can be reduced in cost sufficiently that the economics become attractive enough for large-scale terrestrial generation of power. In this paper, we shall show that amorphous materials can have much higher efficiencies than do crystalline and that the answer to our power generation needs lies not in crystalline but in amorphous technology. At Energy Conversion Devices, Inc. (ECD), we have designed and built a production machine (described by my colleague, Dr. Izu, in a

  15. Development of thin film inorganic membranes for oxygen separation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Hyo Jeong

    2012-08-22

    Membrane-based gas separation systems are noteworthy among technological options for carbon capture and storage (CCS), which is an important strategy to reduce CO{sub 2} emitted from point sources, e.g. mainly fossil power plants. In Oxyfuel-Combustion and Pre-Combustion of CCS power plant concepts oxygen separation from air is required. To meet this requirement oxygen transport membranes (OTM) consisting of gastight mixed ionic electronic conductors (MIEC) are proposed, which are associated with significantly lower efficiency losses compared with conventional air separation technologies. For cost effective application a maximum oxygen flux has to be achieved to reduce the membrane area. This can be met by reduction of membrane thickness. Therefore, the reduction of the membrane thickness to the micrometer range or even below is aimed in the present thesis. Ce{sub 0.8}Gd{sub 0.2}O{sub 2-{delta}} (CGO) with fluorite crystal structure and La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF) with perovskite crystal structure were developed as thin film membrane. CGO is expected to be more stable than other potential MIEC membranes in reducing atmospheres and to achieve sufficient oxygen permeation, e.g. in syngas production or petrol chemistry. LSCF is expected to be highly permeable with an acceptable chemical stability in Oxyfuel-combustion. Various porous ceramic substrates were prepared by vacuum-slip-casting and warm-pressing, and then characterized for porosity, gas-permeability and surface roughness. Subsequently, two approaches to fabrication of thin film membranes were investigated, which are wetchemical deposition (WCD) and physical vapor deposition (PVD). For WCD, nano-dispersions and colloidal sols were prepared for membrane top-layer and/or interlayer. When CGO nano-dispersion (NDCGO) was spin-coated as thin film membrane, the gastightness of sintered membranes was increased with decrease in spinning time and increase in concentration of

  16. Coupling spin qubits via superconductors

    DEFF Research Database (Denmark)

    Leijnse, Martin; Flensberg, Karsten

    2013-01-01

    We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed...... Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled...... to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length....

  17. Evaluating superconductors for microwave applications

    International Nuclear Information System (INIS)

    Hammond, B.; Bybokas, J.

    1989-01-01

    It is becoming increasingly obvious that some of the earliest applications for high Tc superconductors will be in the microwave market. While this is a major opportunity for the superconductor community, it also represents a significant challenge. At DC or low frequencies a superconductor can be easily characterized by simple measurements of resistivity and magnetic susceptibility versus temperature. These parameters are fundamental to superconductor characterization and various methods exist for measuring them. The only valid way to determine the microwave characteristics of a superconductor is to measure it at microwave frequencies. It is for this reason that measuring microwave surface resistance has emerged as one of the most demanding and telling tests for materials intended for high frequency applications. In this article, the theory of microwave surface resistance is discussed. Methods for characterizing surface resistance theoretically and by practical implementation are described

  18. New possibilities for superconductor electronics

    International Nuclear Information System (INIS)

    Likharev, K.K.; Semenov, V.K.; Zorin, A.B.

    1989-01-01

    Situation in the superconducting electronics, the field being developed since mid '60s has changed drastically recently as a result of not only discovery of the high-T c superconductivity, but also of the nearly simultaneous invention of several novel electronic devices. A detailed analysis of the new situation and prospects of this important field was carried out recently by the present authors of this paper. A complete report on our analysis is being published elsewhere, while in this paper we are presenting a brief summary of its results. The analysis has shown that the virtually only advantage which can arise from applications of the high-T c superconductors in electronics is a drastic reduction of the refrigeration costs, rather than an improvement of the device performance

  19. Development of novel UV emitting single crystalline film scintillators

    Science.gov (United States)

    Zorenko, Yu; Gorbenko, V.; Savchyn, V.; Voznyak, T.; Nikl, M.; Mares, J. A.; Martin, T.; Douissard, P.-A.

    2011-04-01

    The work is dedicated to development of new types of UV -emitting scintillators based on single crystalline films (SCF) of aluminimum perovskites and garnets grown by the liquid phase epitaxy (LPE) method. The development of the following three types of UV SCF scintillators is considered in this work: i) Ce-doped SCF of Y-Lu-Al-perovskites with Ce3+ emission in the 360-370 nm range with a decay time of 16-17 ns; ii) Pr-doped SCF of Y-Lu-Al garnets with Pr3+ emission in the 300-400 nm range with a decay time of 13-17 ns; iii) La3+ and Sc3+ doped SCF of Y-Lu-Al-garnets, emitting in the 290-400 nm range due to formation of the LaY,Lu, ScY,Lu and ScAl centers with decay time of 250-575 ns. The results of testing the several novel UV-emitting SCFs scintillators for visualization of X-ray images at ESFR are presented. It is shown that the UV emission of the LuAG:Sc, LuAG:La and LuAG:Pr SCFs is efficient enough for conversion of X-ray to the UV light and that these scintillators can be used for improvement of the resolution of imaging detectors in synchrotron radiation applications.

  20. Development of novel UV emitting single crystalline film scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zorenko, Yu; Gorbenko, V; Savchyn, V; Voznyak, T [Laboratory of Opoelectronic Materials (LOM), Electronics Department of Ivan Franko National University of Lviv, 79017 Lviv (Ukraine); Nikl, M; Mares, J A [Institute of Physics of ASCR, 162 53 Prague (Czech Republic); Martin, T; Douissard, P-A, E-mail: zorenko@electronics.wups.lviv.ua [ESRF, Instrument Support Group, 6 rue Jules Horoeitz, 38043 Grenoble (France)

    2011-04-01

    The work is dedicated to development of new types of UV -emitting scintillators based on single crystalline films (SCF) of aluminium perovskites and garnets grown by the liquid phase epitaxy (LPE) method. The development of the following three types of UV SCF scintillators is considered in this work: i) Ce-doped SCF of Y-Lu-Al-perovskites with Ce{sup 3+} emission in the 360-370 nm range with a decay time of 16-17 ns; ii) Pr-doped SCF of Y-Lu-Al garnets with Pr{sup 3+} emission in the 300-400 nm range with a decay time of 13-17 ns; iii) La{sup 3+} and Sc{sup 3+} doped SCF of Y-Lu-Al-garnets, emitting in the 290-400 nm range due to formation of the La{sub Y,Lu}, Sc{sub Y,Lu} and Sc{sub Al} centers with decay time of 250-575 ns. The results of testing the several novel UV-emitting SCFs scintillators for visualization of X-ray images at ESFR are presented. It is shown that the UV emission of the LuAG:Sc, LuAG:La and LuAG:Pr SCFs is efficient enough for conversion of X-ray to the UV light and that these scintillators can be used for improvement of the resolution of imaging detectors in synchrotron radiation applications.

  1. Development of a Taste-Masked Orodispersible Film Containing Dimenhydrinate

    Directory of Open Access Journals (Sweden)

    Jörg Breitkreutz

    2012-10-01

    Full Text Available Orodispersible dosage forms are promising new approaches for drug delivery. They enable an easy application, as there is no need to drink high amounts of liquids or swallow large solid dosage forms. The aim of the study was to develop an orodispersible film (ODF as an alternative to tablets, syrups or suppositories for the treatment of vomiting and nausea, especially for the pediatric population. Formulations were investigated by X-ray diffraction, scanning electron and polarized light microscopy. Additionally, two commercially available electronic taste sensing systems were used to investigate the applied taste-masking strategies. Results obtained from X-ray-diffraction and polarized light microscopy showed no recrystallization of dimenhydrinate in the formulation when cyclodextrin or maltodextrin were used as solubilizing and complexing agent. All ODFs showed fast disintegration depending on the characterization method. In order to get taste information, the dimenhydrinate formulations were analytically compared to pure drug and drug-free formulations by electronic tongues. Results obtained from both systems are comparable and were used together for the first time. It was possible to develop an ODF of dimenhydrinate that is fast disintegrating even in small volumes of liquid. Furthermore, in vitro taste assessment by two electronic tongues revealed taste-masking effects by the excipients.

  2. Zirconia thin films from aqueous precursors: Processing, microstructural development, and epitaxial growth

    International Nuclear Information System (INIS)

    Miller, K.T.

    1991-01-01

    Thin films of ZrO 2 (Y 2 O 3 ) were prepared from aqueous salt precursors by spin coating. Films were pyrolyzed to produce porous polycrystalline thin films of 5-10 nm grain size. Subsequent microstructural development depends greatly upon the nature of the substrate. Upon randomly oriented sapphire, the films initially sintered to full density; further heat treatment and grain growth causes these films to break into interconnected islands and finally isolated particles. Thermodynamic calculations predict that breakup is energetically favorable when the grain-size film-thickness ratio exceeds a critical value. Upon basal-plane-oriented sapphire, grain growth and breakup prefer the (100) oriented grains, presumably because this orientation is a special interface of low energy. The isolated, oriented grains produced by film breakup act as seeds for the growth of newly deposited material. Upon (100) cubic zirconia, true epitaxial films develop. Epitaxial growth was observed for lattice mismatches up to 1.59%. Growth proceeds from a fine epitaxial layer which is produced during the initial stages of heat treatment, consuming the porous polycrystalline material and producing a dense epitaxial thin film whose misfit is accommodated by a combination of film strain and misfit dislocations

  3. Development, characterization and potential applications of edible film from seaweed (Kappaphycus alvarezii)

    Science.gov (United States)

    Moey, Siah Watt; Abdullah, Aminah; Ahmad, Ishak

    2014-09-01

    A new patent pending process is proposed in this study to produce edible film directly from seaweed (Kappaphycus alvarezii). Seaweed together with other ingredients had been used to produce the film through casting technique. Physical and mechanical tests were performed on the edible film to examine the thickness, colour, transparency, solubility, tensile strength, elongation at break, water permeability rate, oxygen permeability rate and surface morphology. The produced film was transparent, stretchable, sealable and have basic properties for applications in food, pharmaceutical, cosmetic, toiletries and also agricultural industries. Edible film was successfully developed directly from dry seaweed instead of using alginate and carrageenan. The edible film processing method developed in this research was easier and cheaper compared with the method by using alginate and carrageenan.

  4. Dynamics of vortices in planar and tubular microstructured superconductors

    International Nuclear Information System (INIS)

    Fomin, V. M.

    2011-01-01

    Full text: Nucleation and denucleation of vortices as well as their guided motion between antidots are key issues to design methods for controlling the vortex manipulation in micro patterned thin films and self-assembled micro tubes. The vortex dynamics in micro structured superconductors is modelled using an adaptive numerical approach on the basis of the time dependent Ginzburg-Landau equations. Evolution of the order parameter and the current density is analyzed for superconducting YBCO films with different patterns of antidots. The resulting picture of the accumulated vortex trajectories clearly reveals a guided motion between the antidots. Dynamics of correlated vortices in superconductor tubes in a magnetic field, which is perpendicular to their axes, is governed by the curvature. I acknowledge fruitful collaboration with R. Woerdenweber and O. G. Schmidt. (author)

  5. RF Characterization of Niobium Films for Superconducting Cavities

    CERN Document Server

    Aull† , S; Doebert, S; Junginger, T; Ehiasarian, AP; Knobloch, J; Terenziani, G

    2013-01-01

    The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. Niobium films on copper substrates have several advantages over bulk niobium cavities. HIPIMS (High-power impulse magnetron sputtering) is a promising technique to increase the quality and therefore the performance of niobium films. This contribution will introduce CERNs recently developed HIPIMS coating apparatus. Moreover, first results of niobium coated copper samples will be presented, revealing the dominant loss mechanisms.

  6. Iron pnictide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tegel, Marcus Christian

    2011-03-22

    The scope of this dissertation therefore has not only been the synthesis of various new superconducting and non-superconducting iron pnictides of several structural families but also their in-depth crystallographic and physical characterisation. In Chapters 3 - 6, the family of the ZrCuSiAs-type (1111) compounds is subject of discussion. The solid solution series La(Co{sub x}Fe{sub 1-x})PO is analysed regarding magnetic and superconducting properties and the new compounds EuMnPF and REZnPO, as well as the new superconductor parent compound SrFeAsF are presented. Chapters 7 - 9 are dedicated to the new iron arsenide superconductors of the ThCr{sub 2}Si{sub 2}-type (122 family). Therein, also the discovery of the first superconductor in this structural family, Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}, is unveiled. A detailed examination of the complete solid solution series (Ba{sub 1-x}K{sub x})Fe{sub 2}As{sub 2} is presented. Moreover, the crystallographic phase transitions of the closely related compounds SrFe{sub 2}As{sub 2} and EuFe{sub 2}As{sub 2} are characterised and the superconductors Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} and Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} are examined for magnetic and phononic excitations. In Chapter 10, the redetermined crystal structure of the superconductor Fe(Se{sub 1-x}Te{sub x}) (11-type) is presented from a chemist's point of view. Chapters 11 - 14 look into the superconducting and non-superconducting iron arsenides of more complex structural families (32522-type and 21311-type). Therein, crystallographic and magnetic details of Sr{sub 3}Sc{sub 2}O{sub 5}Fe{sub 2}As{sub 2} are presented and Ba{sub 2}ScO{sub 3}FeAs and Sr{sub 2}CrO{sub 3}FeAs, the first two members of the new 21311-type are portrayed. Sr{sub 2}CrO{sub 3}FeAs is looked at in close detail with various methods, so e.g. the spin structure of the magnetically ordered compound is solved and a possible reason for the absence of superconductivity in this compound is

  7. Iron pnictide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Tegel, Marcus Christian

    2011-03-22

    The scope of this dissertation therefore has not only been the synthesis of various new superconducting and non-superconducting iron pnictides of several structural families but also their in-depth crystallographic and physical characterisation. In Chapters 3 - 6, the family of the ZrCuSiAs-type (1111) compounds is subject of discussion. The solid solution series La(Co{sub x}Fe{sub 1-x})PO is analysed regarding magnetic and superconducting properties and the new compounds EuMnPF and REZnPO, as well as the new superconductor parent compound SrFeAsF are presented. Chapters 7 - 9 are dedicated to the new iron arsenide superconductors of the ThCr{sub 2}Si{sub 2}-type (122 family). Therein, also the discovery of the first superconductor in this structural family, Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2}, is unveiled. A detailed examination of the complete solid solution series (Ba{sub 1-x}K{sub x})Fe{sub 2}As{sub 2} is presented. Moreover, the crystallographic phase transitions of the closely related compounds SrFe{sub 2}As{sub 2} and EuFe{sub 2}As{sub 2} are characterised and the superconductors Sr{sub 1-x}K{sub x}Fe{sub 2}As{sub 2} and Ca{sub 1-x}Na{sub x}Fe{sub 2}As{sub 2} are examined for magnetic and phononic excitations. In Chapter 10, the redetermined crystal structure of the superconductor Fe(Se{sub 1-x}Te{sub x}) (11-type) is presented from a chemist's point of view. Chapters 11 - 14 look into the superconducting and non-superconducting iron arsenides of more complex structural families (32522-type and 21311-type). Therein, crystallographic and magnetic details of Sr{sub 3}Sc{sub 2}O{sub 5}Fe{sub 2}As{sub 2} are presented and Ba{sub 2}ScO{sub 3}FeAs and Sr{sub 2}CrO{sub 3}FeAs, the first two members of the new 21311-type are portrayed. Sr{sub 2}CrO{sub 3}FeAs is looked at in close detail with various methods, so e.g. the spin structure of the magnetically ordered compound is solved and a possible reason for the absence of superconductivity in this compound

  8. Superconductors go organic

    International Nuclear Information System (INIS)

    Singleton, John; Mielke, Charles

    2002-01-01

    Superconductors made from organic molecules are revealing fascinating new physics and could offer huge technological potential as well. Solid-state physicists are simple people. They believe that basic research is best carried out on chemically simple materials. Traditionally they have focused on inorganic elements, alloys, and other straightforward compounds. This approach has provided some notable successes. For example, any physicist over 35 will remember the huge fuss surrounding the discovery of high-temperature cuprate superconductors in 1986, which led to the infamous 'Woodstock of physics' meeting the following year. Just before the cuprates were discovered, however, an alternative view had begun to emerge. Physical chemists such as Klaus Bechgaard, Peter Day, Gunzi Saito, Viktor Schegolev and Jack Williams were suggesting that the 'simple-materials-are-best' assumption was misplaced. They argued that some of the most exciting studies in solid-state physics can - and should - be attempted on crystalline organic materials. Although chemically complex, such materials are beautifully simple in other ways, and they can, for example, provide much more information about basic phenomena like superconductivity and magnetism than supposedly simple materials. Physicists eventually embraced these materials with enthusiasm, and the number of papers on crystalline organic metals overtook those on the high-temperature cuprate superconductors three years ago. The gap has widened ever since, and the fact that God and a billion years of evolution have produced a processor based on three-dimensional arrays of molecules, rather than silicon or gallium-arsenide chips, is taken as a good omen by those working in the field. (U.K.)

  9. Indian meal moth (Plodia interpunctella)-resistant food packaging film development using microencapsulated cinnamon oil.

    Science.gov (United States)

    Kim, In-Hah; Song, Ah Young; Han, Jaejoon; Park, Ki Hwan; Min, Sea C

    2014-10-01

    Insect-resistant laminate films containing microencapsulated cinnamon oil (CO) were developed to protect food products from the Indian meal moth (Plodia interpunctella). CO microencapsulated with polyvinyl alcohol was incorporated with a printing ink and the ink mixture was applied to a low-density polyethylene (LDPE) film as an ink coating. The coated LDPE surface was laminated with a polypropylene film. The laminate film impeded the invasion of moth larvae and repelled the larvae. The periods of time during which cinnamaldehyde level in the film remained above a minimum repelling concentration, predicted from the concentration profile, were 21, 21, and 10 d for cookies, chocolate, and caramel, respectively. Coating with microencapsulated ink did not alter the tensile or barrier properties of the laminate film. Microencapsulation effectively prevented volatilization of CO. The laminate film can be produced by modern film manufacturing lines and applied to protect food from Indian meal moth damage. The LDPE-PP laminate film developed using microencapsulated cinnamon oil was effective to protect the model foods from the invasion of Indian meal moth larvae. The microencapsulated ink coating did not significantly change the tensile and barrier properties of the LDPE-PP laminate film, implying that replacement of the uncoated with coated laminate would not be an issue with current packaging equipment. The films showed the potential to be produced in commercial film production lines that usually involve high temperatures because of the improved thermal stability of cinnamon oil due to microencapsulation. The microencapsulated system may be extended to other food-packaging films for which the same ink-printing platform is used. © 2014 Institute of Food Technologists®

  10. Simulating atomic-scale phenomena on surfaces of unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kreisel, Andreas; Andersen, Brian [Niels Bohr Institute (Denmark); Choubey, Peayush; Hirschfeld, Peter [Univ. of Florida (United States); Berlijn, Tom [CNMS and CSMD, Oak Ridge National Laboratory (United States)

    2016-07-01

    Interest in atomic scale effects in superconductors has increased because of two general developments: First, the discovery of new materials as the cuprate superconductors, heavy fermion and Fe-based superconductors where the coherence length of the cooper pairs is as small to be comparable to the lattice constant, rendering small scale effects important. Second, the experimental ability to image sub-atomic features using scanning-tunneling microscopy which allows to unravel numerous physical properties of the homogeneous system such as the quasi particle excitation spectra or various types of competing order as well as properties of local disorder. On the theoretical side, the available methods are based on lattice models restricting the spatial resolution of such calculations. In the present project we combine lattice calculations using the Bogoliubov-de Gennes equations describing the superconductor with wave function information containing sub-atomic resolution obtained from ab initio approaches. This allows us to calculate phenomena on surfaces of superconductors as directly measured in scanning tunneling experiments and therefore opens the possibility to identify underlying properties of these materials and explain observed features of disorder. It will be shown how this method applies to the cuprate material Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} and a Fe based superconductor.

  11. Magnetic Scaling in Superconductors

    International Nuclear Information System (INIS)

    Lawrie, I.D.

    1997-01-01

    The Ginzburg-Landau-Wilson superconductor in a magnetic field B is considered in the approximation that magnetic-field fluctuations are neglected. A formulation of perturbation theory is presented in which multiloop calculations fully retaining all Landau levels are tractable. A 2-loop calculation shows that, near the zero-field critical point, the singular part of the free energy scales as F sing ∼ |t| 2-α F(B|t| -2ν ), where ν is the coherence-length exponent emdash a result which has hitherto been assumed on purely dimensional grounds. copyright 1997 The American Physical Society

  12. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  13. Development of orodispersible films with selected Indonesian medicinal plant extracts

    NARCIS (Netherlands)

    Visser, Johanna; Eugresya, Gabriella; Hinrichs, Wouter; Tjandrawinata, Raymond; Avanti, Christina; Frijlink, H.W.; Woerdenbag, Herman

    2017-01-01

    This study focused on the incorporation into orodispersible films (ODFs) of the dried extracts of five selected Indonesian medicinal plants: Lagerstroemia speciosa (L.) Pers. (LS), Phyllanthus niruri L. (PN), Cinnamomum burmanii Blume (CB), Zingiber officinale Roscoe (ZO) and Phaleria macrocarpa

  14. Development of transparent thin film transistors on PES polymer substrates

    International Nuclear Information System (INIS)

    Yun, Eui-Jung; Jung, Jin-Woo; Ko, Kyung-Nam; Song, Young-Wook; Nam, Hyoung; Cho, Nam-Ihn

    2010-01-01

    In this study, we demonstrate ZnO-based transparent thin film transistors (TTFT's) implemented on polyethersulfone (PES) polymer substrates. For the developed TTFT's, radio-frequency magnetron sputter techniques were used to deposit Al-doped ZnO (AZO) at zero oxygen partial pressures for the source, the drain, and the gate-contact electrodes, undoped ZnO at low oxygen partial pressures for the active p-type layer, and SiO 2 for the gate dielectric. The TTFT's were processed at room temperature (RT), except for a 100 .deg. C sputtering step to deposit the AZO source, drain, and gate-contact electrodes. The devices have bottom-gate structures with top contacts, are optically transparent, and operate in an enhancement mode with a threshold voltage of +13 V, a mobility of 0.1 cm 2 /Vs, an on-off ratio of about 0.5 x 10 3 and, a sub-threshold slope of 4.1 V/decade.

  15. Coincident photoelectron spectroscopy on superconductors

    International Nuclear Information System (INIS)

    Voss, Stefan

    2011-01-01

    Aim of the performed experiments of this thesis was to attempt to detect Cooper pairs as carriers of the superconducting current directly by means of the photoelectric effect. The method of the coincident photoelectron spectroscopy aims thereby at the detection of two coherently emitted electrons by the interaction with a photon. Because electrostatic analyzers typically cover only a very small spatial angle, which goes along with very low coincidence rates, in connection with this thesis a time-of-flight projection system has been developed, which maps nearly the whole spatial angle on a position-resolving detector. The pulsed light source in form of special synchrotron radiation necessary for the measurement has been adjusted so weak, that only single photons could arrive at the sample. Spectroscoped were beside test measurements on silver layers both a lead monocrystal as representative of the classical BCS superconductors and monocrystalline Bi 2 Sr 2 CaCu 2 O 8 from the family of the high-temperature superconductors. With excitation energies up to 40 eV could be shown that sufficiently smooth and clean surfaces in the superconducting phase exhibit within the resolving power of about 0.5 eV no recognizable differences in comparison to the normally conducting phase. Beside these studies furthermore the simple photoemission at the different samples and especially in the case of the lead crystal is treated, because here no comparable results are known. Thereby the whole momentum space is discussed and the Fermi surface established as three-dimensional model, by means of which the measurement results are discussed. in the theoretical descriptions different models for the Cooper-pair production are presented, whereby to the momentum exchange with the crystal a special role is attributed, because this can only occur in direct excitations via discrete lattice vectors.

  16. First International Public Health Film Competition 2016-reflections on the development and use of competition judging criteria.

    Science.gov (United States)

    Hoang, U; Luna, P; Russell, P; Bergonzi-King, L; Ashton, J; McCarthy, C; Donovan, H; Inman, P; Seminog, O; Botchway, S

    2018-03-01

    Film competitions can be a helpful method to understand issues of quality in health films. In this paper, we describe the development and use of explicit quality criteria to identify the 'best' films for the first ever international public health film competition. A film selection committee encompassing a range of stakeholders was compiled. The committee drew up 10 explicit quality criteria to judge films drawing upon other film festival's selection criteria. These criteria were then applied to a broad range of health-related films entered into a film competition to select the 'best' film to screen. Eighty-four films from 20 different countries were submitted to the public health film competition. The originality of the subject covered by the film, the public health importance of the issue and story-telling approach in the film were found to be the most discriminatory criteria to select films. Selection of health films for festivals can be undertaken using explicit quality criteria. There are a number of advantages to such an approach; however, explicit selection involves a large commitment of resources from film festival organizers and there is further research required to test the validity of the quality criteria applied to health-related films.

  17. Development of film antenna for diversity reception; Diversity taio film antenna no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Shigeta, K; Taniguchi, T; Kubota, K [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    Based on the principle of capacitance-loaded window antennas, a new film antenna construction pasting an antenna element on a defogger element printed on a rear window was found. The film antennas show high reception performance, and can be used as television diversity antennas or a VICS-FM multiplex antenna. This paper describes the antenna design concept, the antenna construction and the application to a recreational vehicle which styling is 1.3-Box wagon for the electric accessory. 2 refs., 11 figs.

  18. Development of thermoplastic starch blown film by incorporating plasticized chitosan.

    Science.gov (United States)

    Dang, Khanh Minh; Yoksan, Rangrong

    2015-01-22

    The objective of the present work was to improve blown film extrusion processability and properties of thermoplastic starch (TPS) film by incorporating plasticized chitosan, with a content of 0.37-1.45%. The effects of chitosan on extrusion processability and melt flow ability of TPS, as well as that on appearance, optical properties, thermal properties, viscoelastic properties and tensile properties of the films were investigated. The possible interactions between chitosan and starch molecules were evaluated by FTIR and XRD techniques. Chitosan and starch molecules could interact via hydrogen bonds, as confirmed from the blue shift of OH bands and the reduction of V-type crystal formation. Although the incorporation of chitosan caused decreased extensibility and melt flow ability, as well as increased yellowness and opacity, the films possessed better extrusion processability, increased tensile strength, rigidity, thermal stability and UV absorption, as well as reduced water absorption and surface stickiness. The obtained TPS/chitosan-based films offer real potential application in the food industry, e.g. as edible films. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Pinning and creep in superconductors

    International Nuclear Information System (INIS)

    Ovchinnikov, Yu.N.

    1994-01-01

    All superconductors can be separated into two large groups: type I and type II. The behaviour of these two groups in a magnetic field is quite different. The superconductors of type I, in a strong magnetic field, enter the intermediate state. Phenomenological picture of this state was given by Landau. The type II superconductors, in strong magnetic fields, form the mixed state (or Shubnikov phase). The microscopic picture of the mixed state was given by Abrikosov on the basis of Ginzburg-Landau equations. In ideal homogeneous superconductors the free energy is not changed if all the vortex structure is shifted on some distance u. The transport current will be proportional, therefore, to the electric field E. All the real superconductors, however, are inhomogeneous. Inhomogeneities interact with vortex lattice and pin it. In this new state the transport current below some critical value does not lead to the motion of the flux lattice and to the energy dissipation. The value of critical current strongly depends on the type of inhomogeneities, on the value of magnetic field and on temperature. In new layered superconductors, the critical current depends also on the orientation of the magnetic field B with respect to the layer planes. Temperature and quantum fluctuations lead to the transition between different metastable states in superconductors with current. As a result, the vortex lattice slowly moves (creep phenomenon). Below we will briefly discuss all these phenomena. (orig.)

  20. What can Andreev bound states tell us about superconductors?

    Science.gov (United States)

    Millo, Oded; Koren, Gad

    2018-08-06

    Zero-energy Andreev bound states, which manifest themselves in the tunnelling spectra as zero-bias conductance peaks (ZBCPs), are abundant at interfaces between superconductors and other materials and on the nodal surface of high-temperature superconductors. In this review, we focus on the information such excitations can provide on the properties of superconductor systems. First, a general introduction to the physics of Andreev bound states in superconductor/normal metal interfaces is given with a particular emphasis on why they appear at zero energy in d -wave superconductors. Then, specific spectroscopic tunnelling studies of thin films, bilayers and junctions are described, focusing on the corresponding ZBCP features. Scanning tunnelling spectroscopy (STS) studies show that the ZBCPs on the c -axis YBa 2 Cu 3 O 7- δ (YBCO) films are correlated with the surface morphology and appear only in proximity to (110) facets. STS on c -axis La 1.88 Sr 0.12 CuO 4 (LSCO) films exhibiting the 1/8 anomaly shows spatially modulated peaks near zero bias associated with the anti-phase ordering of the d -wave order parameter predicted at this doping level. ZBCPs were also found in micrometre-size edge junctions of YBCO/SrRuO 3 /YBCO, where SrRuO 3 is ferromagnetic. Here, the results are consistent with a crossed Andreev reflection effect (CARE) at the narrow domain walls of the SrRuO 3 ZBCPs measured in STS studies of manganite/cuprate bilayers could not be attributed to CARE because the manganite's domain wall is much larger than the coherence length in YBCO, and instead are attributed to proximity-induced triplet-pairing superconductivity with non-conventional symmetry. And finally, ZBCPs found in junctions of non-intentionally doped topological insulator films of Bi 2 Se 3 and the s -wave superconductor NbN are attributed to proximity-induced p x  + ip y triplet order parameter in the topological material.This article is part of the theme issue 'Andreev bound states'.

  1. Development of Antimicrobial Biocomposite Films to Preserve the Quality of Bread.

    Science.gov (United States)

    Figueroa-Lopez, Kelly J; Andrade-Mahecha, Margarita María; Torres-Vargas, Olga Lucía

    2018-01-19

    This study focused on the development of gelatin-based films with incorporation of microcrystalline cellulose as reinforcement material. Clove ( Syzygium aromaticum ), nutmeg ( Myristica fragrans ), and black pepper ( Piper nigrum ) oleoresins containing antimicrobial compounds of natural origin were incorporated into the films. The mechanical, thermal, optical, and structural properties, as well as color, seal strength and permeability to water vapor, light, and oil of the films were determined. Adding oleoresins to the gelatin matrix increased the elongation of the material and significantly diminished its permeability to water vapor and oil. Evaluation of the potential use of films containing different oleoresins as bread packaging material was influenced by the film properties. The biocomposite film containing oleoresin from black pepper was the most effective packaging material for maintaining bread's quality characteristics.

  2. Gelatin capsule waste: new source of protein to develop a biodegradable film

    Directory of Open Access Journals (Sweden)

    Camila de Campo

    Full Text Available Abstract This work aimed to develop biodegradable films utilizing a new source of gelatin derived from the nutraceutical capsule manufacture waste of coconut with safflower oil, coconut oil and safflower oil. The mechanical, physicochemical, barrier, optical, biodegradation, thermal and morphological properties were evaluated. All films showed low water vapor permeability, intermediate water solubility and high elongation at break. In addition, the films exhibited excellent barrier ability to ultraviolet light. After 15 days of soil burial degradation, the films lost over 68% of initial weight. Scanning electron microscopy showed an appearance free of pores, cracks or bubbles. Furthermore the films showed similar characteristics independent of the waste utilized. The results demonstrated that all the biodegradable films prepared presented appropriate characteristics to be used as substitute to synthetic packaging.

  3. Development of a metrology method for composition and thickness of barium strontium titanate thin films

    International Nuclear Information System (INIS)

    Remmel, Thomas; Werho, Dennis; Liu, Ran; Chu, Peir

    1998-01-01

    Thin films of barium strontium titanate (BST) are being investigated as the charge storage dielectric in advanced memory devices, due to their promise for high dielectric constant. Since the capacitance of BST films is a function of both stoichiometry and thickness, implementation into manufacturing requires precise metrology methods to monitor both of these properties. This is no small challenge, considering the BST film thicknesses are 60 nm or less. A metrology method was developed based on X-ray Fluorescence and applied to the measurement of stoichiometry and thickness of BST thin films in a variety of applications

  4. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  5. Vortex cutting in superconductors

    Science.gov (United States)

    Vlasko-Vlasov, Vitalii K.; Koshelev, Alexei E.; Glatz, Andreas; Welp, Ulrich; Kwok, Wai-K.

    2015-03-01

    Unlike illusive magnetic field lines in vacuum, magnetic vortices in superconductors are real physical strings, which interact with the sample surface, crystal structure defects, and with each other. We address the complex and poorly understood process of vortex cutting via a comprehensive set of magneto-optic experiments which allow us to visualize vortex patterns at magnetization of a nearly twin-free YBCO crystal by crossing magnetic fields of different orientations. We observe a pronounced anisotropy in the flux dynamics under crossing fields and the filamentation of induced supercurrents associated with the staircase vortex structure expected in layered cuprates, flux cutting effects, and angular vortex instabilities predicted for anisotropic superconductors. At some field angles, we find formation of the vortex domains following a type-I phase transition in the vortex state accompanied by an abrupt change in the vortex orientation. To clarify the vortex cutting scenario we performed time-dependent Ginzburg-Landau simulations, which confirmed formation of sharp vortex fronts observed in the experiment and revealed a left-handed helical instability responsible for the rotation of vortices. This work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division.

  6. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo

    2007-01-01

    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  7. Method for fabrication of high temperature superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam [Hinsdale, IL; Ma, Beihai [Naperville, IL; Miller, Dean [Darien, IL

    2009-07-14

    A layered article of manufacture and a method of manufacturing same is disclosed. A substrate has a biaxially textured MgO crystalline layer having the c-axes thereof inclined with respect to the plane of the substrate deposited thereon. A layer of one or more of YSZ or Y.sub.2O.sub.3 and then a layer of CeO.sub.2 is deposited on the MgO. A crystalline superconductor layer with the c-axes thereof normal to the plane of the substrate is deposited on the CeO.sub.2 layer. Deposition of the MgO layer on the substrate is by the inclined substrate deposition method developed at Argonne National Laboratory. Preferably, the MgO has the c-axes thereof inclined with respect to the normal to the substrate in the range of from about 10.degree. to about 40.degree. and YBCO superconductors are used.

  8. The improved damping of superconductor bearings for 35 kWh superconductor flywheel energy storage system

    International Nuclear Information System (INIS)

    Han, Y.H.; Park, B.J.; Jung, S.Y.; Han, S.C.; Lee, W.R.; Bae, Y.C.

    2013-01-01

    Highlights: ► We made a 35 kWh superconductor flywheel energy storage system. ► The damping coefficient of the superconductor bearing was increased over 3000 N s/m. ► The source of damping was discussed. -- Abstract: A 35 kWh Superconductor Flywheel Energy Storage system (SFES) using hybrid bearing sets, which is composed of a high temperature superconductor (HTS) bearing and an active magnet damper (AMD), has been developed at KEPCO Research Institute (KEPRI). Damping is a source of energy loss but necessary for the stability of the flywheel system. We found that the damping of HTS bearings can be improved by thermal insulating bolts, which play a role of passive type external damper. To investigate the source of the increased damping, damping coefficients were measured with HTS bearings using insulating bolts made of three kinds of polymer materials. The damping coefficient was raised over 3000 N s/m in the case of PEEK bolts. The value was almost a quarter of the AMD. In this study, thermoelastic and Coulomb friction damping mechanisms are discussed. The main damping mechanism was the thermoelastic damping of the bolts themselves. And interfacial gap between the insulating bolt and metal chamber, which increased during the cooling process, was considered to be the cause of the anisotropic damping coefficients. Finally, the effects of the HTS bearings on the first critical speed are shown

  9. Ac losses of transposed superconductors

    International Nuclear Information System (INIS)

    Eckert, D.; Enderlein, G.; Lange, F.

    1975-01-01

    Eastham and Rhodes published results of loss measurements on transposed superconducting NbTi cables and concluded basing on an extrapolation to very large numbers of wires that transposed superconductors could be used favorably in cables for power transmission. There are some reasons to question the correctness of their extrapolation. Losses were calculated for transposed superconductors in self field and got results different from those of Eastham and Rhodes. Loss measurements were performed the results of which give evidence for the correctness of our calculations. The results lead to the conclusion that the use of transposed cables of irreversible type 2 superconductors for power transmission is not advantageous

  10. Quality control for dental X-rays equipment and film developers

    International Nuclear Information System (INIS)

    Pomares C, Martin

    1998-01-01

    Quality control in five dental X-ray equipments, film and film developers was done. It was for evaluating the radiologic practices in the odontologic services too. This work was made based on international standards, the results will be used for future works in quality assurance in dental radiology

  11. Conductors, semiconductors, superconductors. A compact introduction to history, development, and theory of solid-state physics. 2. ed.

    International Nuclear Information System (INIS)

    Huebener, Rudolf

    2017-01-01

    The present book is a strongly revised and supplemented edition of the title: ''Kristalle: Spiefeld der Elektronen'', published scarcely ten years ago by the same author. Especially the physical contents are explained by the mathematically formulated foundations. The book appeals to students of natural sciences and especially of physics as well as to engineers as introduction to the wide field of solid-state physics, so to speak as motivating prestage to the established and very extensive textbooks. Beside the physical contents the book treats the important role of numerous important and often still very young scientists. By corresponding supplements in this book it is tried to present the fundamental developments in their wide environment.

  12. New superconductors. Pt. B

    International Nuclear Information System (INIS)

    Assmann, H.; Endres, G.; Friedrich, B.; Grosse, J.; Guenther, A.; Heine, K.; Helldoerfer, H.; Herkert, W.; Hofer, G.; Jenovelis, A.; Kleinlein, W.; Koerner, F.; Krauth, H.; Kress, B.; Moser, T.; Neumueller, H.W.; Proelss, N.; Schmatjko, K.J.; Schmidt, W.; Seebacher, B.; Stieding, P.; Tenbrink, J.; Uzel, Y.; Wilhelm, M.

    1992-02-01

    Based on the results of the work on thin films, ceramics and measurement techniques performed in part A, the aim of part B 'Conductor development' was to investigate and to evaluate selected fabrication processes suitable for the manufacturing of conductors (tapes, wires) for applicatons in magnet technology and power engineering. Critical current densities j c of about 1 kA/cm 2 (77 K, zero field) were obtained for melt-textured 2212 BiSrCaCuO bulk material and 2212 BiSrCaCuO Ag-wires; but j c strongly decreases in magnetic field B (factor 10 3 at 0.1 T). At 4.2 K, the Ag-wires made by the powder in tube technique (PIT) achieved j c -values of 50 kA/cm 2 and j c (B) is practically not affected by a magnetic field below 320 K (j c =10 kA/cm 2 at 20 T). Therefore, these conductors are intended for applications in high field magnets operated between 4.2 K and 20 K. First test coils (conductor lengths 1.5 m) had somewhat reduced j c =10 kA/cm 2 (4.2 K, zero field) The PIT-technique ws successfully applied with the three layer Bi-compound. j c vlaues up to 35 kA/cm 2 were obtained at 77 K (zero field), which are within the international top values reported so far. Another continuous manufacturing process is the laser melting technique which achieves rapid melting of YBaCuO-layers of 10-20 μm in thickness on (Ag) substrates, jc=1.4-4 kA/cm 2 were obtained without any process optimization using textured precursors made by electrophoretic deposition. As a preliminary step for the proposed high-current demonstration conductor (200 A, 77 K), laser-ablated YBaCuO films were tested on technical substrates (Ni-based alloys) with buffer layers (MgO, ZrO 2 ). The films had good c-axis orientation. Until now it has been not possible to measure j c at 77 K. (orig.). 67 refs., 21 tabs., 131 figs [de

  13. Quasiparticle current in superconductor-semiconductor-superconductor junctions

    International Nuclear Information System (INIS)

    Tartakovskij, A.V.; Fistul', M.V.

    1988-01-01

    It is shown that the quasiparticle current in a superconductor-semiconductor-superconductor junction may significantly increase as a result of resonant passage of the quasiparticle along particular trajectories from periodically situated localized centers. A prediction of the theory is that with increasing junction resistance there should be a change from an excessive current to a insufficient current on the current-voltage characteristics (at high voltages). The effect of transparency of the boundaries on resonance tunneling in such junctions is also investigated

  14. Rf and microwave measurements at Los Alamos on oxide superconductors

    International Nuclear Information System (INIS)

    Migliori, A.; Reagor, D.W.; Peterson, D.E.; Willis, J.O.; Fisk, Z.; Smith, R.C.

    1988-01-01

    Los Alamos National Laboratory has made a substantial commitment to develop oxide superconductors for RF and microwave cavity applications. The program involves materials development, complete microstructure characterization, static thermal and electrical characterization, RF loss measurements and microwave complex-conductivity measurements. Of the high-frequency techniques, three are nearing completion and one has produced preliminary results. Those still under development include a 3 GHz Nb cavity capable of 4 K operation, a LN 2 -cooled 2.25 GHz copper cavity having a Q of 2 x 10 4 , capable of operation from 15 K to 300 K, and a picosecond-laser/photo-diode driven microstripline technique which will provide complex conductivity information from 20 GHz to 200 GHz and from 10 K to 300 K. Because all of the techniques employed sense the impedance of the samples, their sensitivity to intrinsic properties such as conductivity or surface resistance is dependent on sample geometry. However, for easily handled samples, the Nb cavity can detect losses at least four order of magnitude lower than copper, the copper cavity can detect losses two orders of magnitude lower than copper and the microstripline can detect losses comparable to copper. The technique which has produced results is a coaxial microwave bridge. In this work they report results of measurements on sintered samples using the bridge; future work will concentrate on films. 2 references, 1 figure

  15. Development of thin film oxygen transport membranes on metallic supports

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Ye

    2012-04-25

    Asymmetric membrane structure has an attractive potential in the application of O{sub 2}/N{sub 2} gas separation membrane for the future membrane-based fossil fuel power plant using oxyfuel technology, which will reduce the carbon dioxide emission. The aim of this study is the development of a metal supported multi-layer membrane structure with a thin film top membrane layer and porous ceramic interlayers. Four perovskite materials were studied as candidate membrane materials. Material properties of these perovskite materials were investigated and compared. La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF58428) showed sufficient oxygen permeability, an acceptable thermal expansion coefficient and a moderate sintering temperature. Alternatively, Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF5582) is considered obtaining very high oxygen permeability but a higher thermal expansion and a lower thermal stability than LSCF58428. Four different Ni-based alloys were studied as candidate substrate materials in the asymmetric membrane structure. The chromia-scale alloys (Hastelloy X, Inconel 600 and Haynes 214) caused Cr poisoning of the membrane layer material LSCF58428 during high-temperature co-firing in air. NiCoCrAlY with a high Al content (12.7 wt%) was found to be the most promising substrate material. It showed a good chemical compatibility with perovskite materials at high temperatures. In order to bridge the highly porous substrate and the thin top membrane layer interlayers were developed. Two interlayers were coated by screen printing on the porous NiCoCrAlY substrate which was sintered at 1225 C in flowing H{sub 2} atmosphere. Screen printing pastes were optimized by investigating various solvent and binder combinations and various ceramic powder contents. The first interlayer significantly improved the surface quality and the surface pore size has been reduced from 30-50{mu}m on the substrate to few {mu}m on the first

  16. Microgravity Processing of Oxide Superconductors

    Science.gov (United States)

    Olive, James R.; Hofmeister, William H.; Bayuzick, Robert J.; Vlasse, Marcus

    1999-01-01

    Considerable effort has been concentrated on the synthesis and characterization of high T(sub c) oxide superconducting materials. The YBaCuO system has received the most intense study, as this material has shown promise for the application of both thin film and bulk materials. There are many problems with the application of bulk materials- weak links, poor connectivity, small coherence length, oxygen content and control, environmental reactivity, phase stability, incongruent melting behavior, grain boundary contamination, brittle mechanical behavior, and flux creep. The extent to which these problems are intrinsic or associated with processing is the subject of controversy. This study seeks to understand solidification processing of these materials, and to use this knowledge for alternative processing strategies, which, at the very least, will improve the understanding of bulk material properties and deficiencies. In general, the phase diagram studies of the YBaCuO system have concentrated on solid state reactions and on the Y2BaCuO(x) + liquid yields YBa2Cu3O(7-delta) peritectic reaction. Little information is available on the complete melting relations, undercooling, and solidification behavior of these materials. In addition, rare earth substitutions such as Nd and Gd affect the liquidus and phase relations. These materials have promising applications, but lack of information on the high temperature phase relations has hampered research. In general, the understanding of undercooling and solidification of high temperature oxide systems lags behind the science of these phenomena in metallic systems. Therefore, this research investigates the fundamental melting relations, undercooling, and solidification behavior of oxide superconductors with an emphasis on improving ground based synthesis of these materials.

  17. Advantageous grain boundaries in iron pnictide superconductors

    Science.gov (United States)

    Katase, Takayoshi; Ishimaru, Yoshihiro; Tsukamoto, Akira; Hiramatsu, Hidenori; Kamiya, Toshio; Tanabe, Keiichi; Hosono, Hideo

    2011-01-01

    High critical temperature superconductors have zero power consumption and could be used to produce ideal electric power lines. The principal obstacle in fabricating superconducting wires and tapes is grain boundaries—the misalignment of crystalline orientations at grain boundaries, which is unavoidable for polycrystals, largely deteriorates critical current density. Here we report that high critical temperature iron pnictide superconductors have advantages over cuprates with respect to these grain boundary issues. The transport properties through well-defined bicrystal grain boundary junctions with various misorientation angles (θGB) were systematically investigated for cobalt-doped BaFe2As2 (BaFe2As2:Co) epitaxial films fabricated on bicrystal substrates. The critical current density through bicrystal grain boundary (JcBGB) remained high (>1 MA cm−2) and nearly constant up to a critical angle θc of ∼9°, which is substantially larger than the θc of ∼5° for YBa2Cu3O7–δ. Even at θGB>θc, the decay of JcBGB was much slower than that of YBa2Cu3O7–δ. PMID:21811238

  18. Peeled film GaAs solar cell development

    International Nuclear Information System (INIS)

    Wilt, D.M.; Thomas, R.D.; Bailey, S.G.; Brinker, D.J.; DeAngelo, F.L.

    1990-01-01

    Thin film, single crystal gallium arsenide (GaAs) solar cells could exhibit a specific power approaching 700 W/Kg including coverglass. A simple process has been described whereby epitaxial GaAs layers are peeled from a reusable substrate. This process takes advantage of the extreme selectivity (>10 6 ) of the etching rate of aluminum arsenide (AlAs) over GaAs in dilute hydrofloric acid (HF). The intent of this work is to demonstrate the feasibility of using the peeled film technique to fabricate high efficiency, low mass GaAs solar cells. We have successfully produced a peeled film GaAs solar cell. The device, although fractured and missing the aluminum gallium arsenide (Al x Ga 1 - x As) window and antireflective (AR) coating, had a Voc of 874 mV and a fill factor of 68% under AMO illumination

  19. SU-G-TeP2-06: Development of Novel Radiochromic Films for Radiotherapy Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Alqathami, M; Lee, H; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Won Choi, G [UT MD Anderson Cancer Center, Houston, TX-Texas (United States); Blencowe, A [The University of South Australia, South Australia, SA (Australia); Wen, Z [MD Anderson Cancer Center, Houston, TX (United States); Adamovics, J [Department of Chemistry and Biology, Rider University, Skillman, NJ (United States)

    2016-06-15

    Purpose: To develop and evaluate novel radiochromic films for quality assurance in radiotherapy dosimetry. Materials and Methods: Novel radiochromic film compositions were formulated using leuco crystal violet (LCV) as a reporting system and tetrabromoethane as a free radical source. The film matrix used consisted of polyurethane polymer mixed with dibutyl phthalate plasticizer (20 wt%). The concentration of the radical initiator was kept constant at 10 wt% and the concentration of the LCV dye varied (1 and 2 wt%). To ensure uniform thickness of the film, its precursors were sandwiched between two pieces of glass separated by a 1 mm gap between during the curing process. The films were cut into pieces and were irradiated with a 6 MV X-ray beam to selected doses. The change in optical density was measured using a flatbed scanner and a spectrophotometer. Results: The results showed that all film formulations exhibited a linear response with dose and an absorption maximum at ∼ 590 nm. The formulation with 2 wt% LCV was ∼ 30% more sensitive to dose than the formulation with 1 wt% LCV. Both films were very deformable. In addition, the radiochromic response of the film was found to bleach over a short period of time (few weeks) allowing the film to be reused for dose verification measurements. Conclusion: Both film formulations displayed excellent sensitivity and linearity to radiation dose and thus can be used for the 2D dosimetry of clinical megavoltage and kilovoltage X-ray beams. In addition, the thickness of the film could easily be increased allowing for their potential use as a deformable bolus material. However, thicker films would need more optimization of the manufacturing procedure to ensure consistent material uniformity and sensitivity are recommended.

  20. Development of a fast dissolving film of epinephrine hydrochloride as a potential anaphylactic treatment for pediatrics.

    Science.gov (United States)

    Alayoubi, Alaadin; Haynes, Lindsay; Patil, Hemlata; Daihom, Baher; Helms, Richard; Almoazen, Hassan

    2017-12-01

    To develop a fast dissolving film strip containing epinephrine HCl for the potential treatment of pediatric anaphylaxis. Four different films have been prepared by solvent casting technique where the percentages of the polymer (Lycoat RS720) were optimized. The polymer percentages were (20%, 25%, 27% and 30%) of the total formulation weighs. The thickness and elastic modulus of the optimized film was evaluated using dynamic mechanical analyzer. Epinephrine content uniformity was assessed using UV at wavelength 280 nm. For the dissolution test, fast dissolving films (FDFs) were evaluated in 500 Simulated Saliva, with 50 rpm. In vivo taste and disintegration evaluation was performed on six healthy volunteers. Films formed by formulations 1, 2 and 3 were too sticky after drying, while formulation 4 that has 30% polymer content formed smooth, transparent, flexible and uniform film, and therefore, it was selected for further testing. The value of elastic modulus was determined at 1.325 MPa. The thickness of the film at different locations was measured at 0.29 mm. Drug content in film was measured at 93% ±10. More than 90% of epinephrine was released from the film within 7.2 min. Bitterness of epinephrine was masked efficiently according to volunteer's comments with average disintegration time of 20 s. This study presents potential proof for using FDFs as a replacement therapy of epinephrine injections for pediatrics.

  1. Development of optical thin film technology for lasers and synchrotron radiation

    International Nuclear Information System (INIS)

    Apparao, K.V.S.R.; Bagchi, T.C.; Sahoo, N.K.

    1985-01-01

    Dielectric multilayer optical thin film devices play an important role not only in the working of lasers but also in different front line research activities using high power lasers and high intensity synchrotron radiation sources. Facilities are set up recently in the Spectroscopy Division to develop the optical thin film design and fabrication technologies indigeneously. Using the facilities thin film devices for different laser applications working in the wavelength range from 300 nm to 1064 nm were developed. Different technical aspects involved in the technology development are briefly described. (author)

  2. Towards ferromagnet/superconductor junctions on graphene

    International Nuclear Information System (INIS)

    Pakkayil, Shijin Babu

    2015-01-01

    to contact graphene or any other semiconductor with a ferromagnet has to overcome one important problem known as ''Conductance mismatch''. To solve the conductance mismatch problem, which had stalled the injection of spin polarised electrons to a semiconductor for many years, in our fabrication method, a thin Al 2 O 3 layer is introduced between the ferromagnet and graphene. The insulating layer is grown using Atomic layer deposition (ALD) with the help of a thin Ti seed layer. Unlike the previously reported method, which treats the entire graphene flake with PTCA (3,4,9,10-perylene tetracarboxylic acid) prior to the ALD process, no such chemical treatment occurs in our fabrication process. Also, the yield of successful devices are higher than the highest yield reported so far (∝30%). The later part of the thesis discusses how this fabrication recipe is further developed to contact graphene with superconducting contacts to produce ferromagnet/superconductor junctions on graphene. The successful spin valve devices produced using the new fabrication process are discussed along with a simple theory of spin transport in graphene. Some of the spin valve devices discussed are fabricated with the help of Ti seed layer (for growing Al 2 O 3 ) and some of them are without. Also, measurement results on devices with varying number of ALD cycles are shown and discussed which helps to decide the optimum number of ALD cycles needed for the best yield and performance. The devices made using Ti seed layer shows better consistency in terms of contact resistances and device performance. Also, ferromagnetic contacts from one device showed perfect tunnel barrier behaviour. Chapter 5 mainly discusses the results of the measurements done on a device which has 4 ferromagnetic contacts and 4 superconducting contacts arranged in a fashion that it forms multiple ferromagnet/superconductor junctions on graphene. Lateral spin valves and Josephson junctions are also part of

  3. Towards ferromagnet/superconductor junctions on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Pakkayil, Shijin Babu

    2015-07-01

    to contact graphene or any other semiconductor with a ferromagnet has to overcome one important problem known as ''Conductance mismatch''. To solve the conductance mismatch problem, which had stalled the injection of spin polarised electrons to a semiconductor for many years, in our fabrication method, a thin Al{sub 2}O{sub 3} layer is introduced between the ferromagnet and graphene. The insulating layer is grown using Atomic layer deposition (ALD) with the help of a thin Ti seed layer. Unlike the previously reported method, which treats the entire graphene flake with PTCA (3,4,9,10-perylene tetracarboxylic acid) prior to the ALD process, no such chemical treatment occurs in our fabrication process. Also, the yield of successful devices are higher than the highest yield reported so far (∝30%). The later part of the thesis discusses how this fabrication recipe is further developed to contact graphene with superconducting contacts to produce ferromagnet/superconductor junctions on graphene. The successful spin valve devices produced using the new fabrication process are discussed along with a simple theory of spin transport in graphene. Some of the spin valve devices discussed are fabricated with the help of Ti seed layer (for growing Al{sub 2}O{sub 3}) and some of them are without. Also, measurement results on devices with varying number of ALD cycles are shown and discussed which helps to decide the optimum number of ALD cycles needed for the best yield and performance. The devices made using Ti seed layer shows better consistency in terms of contact resistances and device performance. Also, ferromagnetic contacts from one device showed perfect tunnel barrier behaviour. Chapter 5 mainly discusses the results of the measurements done on a device which has 4 ferromagnetic contacts and 4 superconducting contacts arranged in a fashion that it forms multiple ferromagnet/superconductor junctions on graphene. Lateral spin valves and Josephson junctions

  4. Preparation of superconductor precursor powders

    Science.gov (United States)

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  5. Superconductor Digital-RF Receiver Systems

    Science.gov (United States)

    Mukhanov, Oleg A.; Kirichenko, Dmitri; Vernik, Igor V.; Filippov, Timur V.; Kirichenko, Alexander; Webber, Robert; Dotsenko, Vladimir; Talalaevskii, Andrei; Tang, Jia Cao; Sahu, Anubhav; Shevchenko, Pavel; Miller, Robert; Kaplan, Steven B.; Sarwana, Saad; Gupta, Deepnarayan

    Digital superconductor electronics has been experiencing rapid maturation with the emergence of smaller-scale, lower-cost communications applications which became the major technology drivers. These applications are primarily in the area of wireless communications, radar, and surveillance as well as in imaging and sensor systems. In these areas, the fundamental advantages of superconductivity translate into system benefits through novel Digital-RF architectures with direct digitization of wide band, high frequency radio frequency (RF) signals. At the same time the availability of relatively small 4K cryocoolers has lowered the foremost market barrier for cryogenically-cooled digital electronic systems. Recently, we have achieved a major breakthrough in the development, demonstration, and successful delivery of the cryocooled superconductor digital-RF receivers directly digitizing signals in a broad range from kilohertz to gigahertz. These essentially hybrid-technology systems combine a variety of superconductor and semiconductor technologies packaged with two-stage commercial cryocoolers: cryogenic Nb mixed-signal and digital circuits based on Rapid Single Flux Quantum (RSFQ) technology, room-temperature amplifiers, FPGA processing and control circuitry. The demonstrated cryocooled digital-RF systems are the world's first and fastest directly digitizing receivers operating with live satellite signals in X-band and performing signal acquisition in HF to L-band at ˜30GHz clock frequencies.

  6. Pressure effect on iron based superconductors

    International Nuclear Information System (INIS)

    Arumugam, S.; Kanagaraj, M.

    2011-01-01

    A tuning of macroscopic thermo dynamical parameters such as temperature, pressure and volume play a crucial role in strongly correlated electron systems especially high T c superconductors, which leads to increasing conductivity as well as effective way of reducing intrinsic magnetic moments. Application of chemical and external pressure exhibits significant increases of critical temperature of recently discovered iron pnictides and chalcogenides superconductors. In this present report, we have investigated hydrostatic pressure effects on resistivity and magnetization of some 1111 type based oxypnictide superconductors such as Co doped CeFeAsO, La 0.8 Th 0.2 FeAsO, Ce 0.6 Y 0.4 FeAsO 0.8 F 0.2 and Yb doped CeFeAsO systems respectively. The initially applied pressure increases the T c and its down to lower value when beyond increasing pressure also has been observed and pressure effects on crystal structure were also discussed. From that all the obtained results reveal that controlling of magnetic instability and structure distortion at higher pressure is a dominant way to further developing of T c of these new ferropnictides compounds. (author)

  7. Study of the nonequilibrium state of superconductors by large quasiparticle injection from an external current source

    International Nuclear Information System (INIS)

    Iguchi, I.

    1977-01-01

    We have studied the nonequilibrium state of superconductors by injecting large numbers of quasiparticles from an external current source into a superconducting film of a tunnel junction with low tunnel resistance (typically 0.1--1 Ω for junction area approx. = 10 -4 cm 2 ). It was observed that there was a critical tunnel current density at which a voltage appeared locally in the part of a superconducting film confined to the junction area. Its values ranged from 10 2 to 10 3 A/cm 2 for bath temperatures well below T/sub c/. Followed by this voltage onset, a transition region corresponding to the nonequilibrium intermediate resistive state was also observed. For further increase of the tunnel current, the local film resistance developed beyond the value of its normal resistance, suggesting that the nonequilibrium state extends far beyond the voltage onset point. A theory based on the modified Rothwarf-Taylor equations and Parker's T* model is presented to compare with the experimental results. The calculated critical current density yielded almost the same order of magnitude as those found experimentally. The detailed behavior, however, deviates from the theoretical predictions although the film makes a second-order transition in the broad range of temperatures. It is also shown using four-terminal analysis that our observations and those by Wong, Yeh, and Langenberg are essentially the same

  8. Fiscal 1998 research report (New Sunshine Project). Research on the total system for development of superconductor power application technology; 1998 nendo seika hokokusho (new sunshine keikaku). Chodendo denryoku oyo gijutsu kaihatsu total system no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    This report summarizes the fiscal 1998 research promoted as a part of New Sunshine Project 'R and D project on development of superconductor power application technology.' This project is composed of R and D of superconductor power application technology (Rank 1), study on the total system (Rank 2), and study on review of introduction effects (Rank 3). The project is promoting R and D of the prototype superconducting generator model and elementary technologies based on the basic plan mainly by the research association. The combination test of the developed armature and the multi- cylindrical rotor model or slow response excitation rotor model was finished, and the test of the quick response excitation rotor model is in promotion. Together with R and D of hardware, this project is also promoting R and D of software through review of the introduction effects of superconducting power equipment. In fiscal 1998, the pre- final review was carried out by the project review sub- committee. 2 times of the committee, 12 times of the sub- committee, and several times of the working group were held until March, 1999. (NEDO)

  9. FY 1996 report on the results of the development of superconductor power application technology. Study of a total system, etc. (Investigational study of the introductory effect); 1996 nendo chodendo denryoku oyo gijutsu kaihatsu seika hokokusho. Total system nado no kenkyu (donyu koka no chosa kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Under the secondary interim assessment made in FY 1995 between the assessment committee of the energy/environment technology development sectional meeting of the Industrial Technology Deliberation Council and NEDO, in this project, the following were conducted in FY 1996: study of trial manufacture of superconductor motor model machine and R and D of element technology (conductor technology/refrigerator technology). The study was proceeded mainly with Super-GM, and as to the motor, the preparation for test on a part of the model machines was finished. Considering FY 1998 which is the final year of this project, the investigational study in FY 1996 aims at accumulating/arranging/analyzing the data which help judge how to proceed with the future R and D of superconductor power application technology continuously based on the secondary interim assessment. For superconductor motor and various superconductor power appliance, economical/technical feasibilities and methods of R and D and surveys of trends in Japan and abroad for the R and D were made important items. Further, 'R and D of the basement of superconductor power application' proposed in the secondary interim assessment (R and D of the combination of elements which become the basement of equipment technology over a stage of parallel R and D of element technology of conductor, etc.) targeted the presentation of concrete details. (NEDO)

  10. FY 1996 report on the results of the development of superconductor power application technology. Study of a total system, etc. (Investigational study of the introductory effect); 1996 nendo chodendo denryoku oyo gijutsu kaihatsu seika hokokusho. Total system nado no kenkyu (donyu koka no chosa kenkyu)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Under the secondary interim assessment made in FY 1995 between the assessment committee of the energy/environment technology development sectional meeting of the Industrial Technology Deliberation Council and NEDO, in this project, the following were conducted in FY 1996: study of trial manufacture of superconductor motor model machine and R and D of element technology (conductor technology/refrigerator technology). The study was proceeded mainly with Super-GM, and as to the motor, the preparation for test on a part of the model machines was finished. Considering FY 1998 which is the final year of this project, the investigational study in FY 1996 aims at accumulating/arranging/analyzing the data which help judge how to proceed with the future R and D of superconductor power application technology continuously based on the secondary interim assessment. For superconductor motor and various superconductor power appliance, economical/technical feasibilities and methods of R and D and surveys of trends in Japan and abroad for the R and D were made important items. Further, 'R and D of the basement of superconductor power application' proposed in the secondary interim assessment (R and D of the combination of elements which become the basement of equipment technology over a stage of parallel R and D of element technology of conductor, etc.) targeted the presentation of concrete details. (NEDO)

  11. Microwave superconductivity for particle accelerators - How the high TC superconductors measure up

    International Nuclear Information System (INIS)

    Padamsee, H.; Green, K.; Gruschus, J.

    1988-01-01

    Application of superconducting niobium cavities to accelerators for high energy physics, nuclear physics and free electron laser is growing rapidly. Cornell has a long standing effort in the development of superconducting RF accelerator technology. Nb cavities developed here from the basis for constructing the world's highest energy electron accelerator for nuclear physics. These cavities have set a standard against which the behavior of the new superconductors must be compared. From available results on dc critical fields, and the energy gap, it appears that the new materials could make a significant impact on the capabilities of future accelerators. Crucial to this assessment, however, are direct microwave loss measurements, together with measurements of the energy gap and RF frequency dependence as well as the behavior at high RF fields. Latest results on these properties for bulk sintered ceramics, thin films and single crystals at RF frequencies of 1.5 and 6 Ghz are presented

  12. Polymeric conductors and superconductors

    International Nuclear Information System (INIS)

    Goodings, E.P.

    1975-01-01

    The production of electrically conductive polymers which are flexible ans capable of being shaped by normal processes, is discussed. The relation between the structure of the polymer and its ability to transport electric charge is considered. The main problem is to combine high conductivity with good processability and it is shown that stacked-planar systems are superior to conjugated polymers. Good mechanical properties have yet to be achieved. In some way the rigid pi-bonded systems must be combined with a conventional sigma-bonded polymer without destroying its flexibility and tensile properties. The structure will contain a radical ion system to provide charge carriers but it is not yet known how to design the polymer structure to give high carrier mobility. Further work is required on organic superconductors in unravelling the relationship between charge carrier mobility and the supermolecular structure of polymers. (UK)

  13. Manufacturing of Superconductors

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Bay, Niels

    Superconducting tapes based on the ceramic high temperature superconductor (HTS) is a new promising product for high current applications such as electro-magnets and current transmission cables. The tapes are made by the oxide powder in tube (OPIT) method implying drawing and rolling of silver...... tubes containing ceramic powder. The final product is a composite tape, where ceramic superconducting fibres are embedded in a silver matrix. The critical current density Je [kA/cm 2 ] is the primary quality parameter of the product. The quality of the superconducting tape depends very much...... in the individual fibres. · The stresses and strains in the deformation zone are analysed. It is concluded that more detailed mechanical tests and a more detailed constitutive plasticity model is desirable in order to improve the precision of the numerical modelling. New test equipment is designed implying the new...

  14. Hybrid Quantum Information Processing with Superconductors and Neutral Atoms

    Science.gov (United States)

    McDermott, Robert

    Hybrid approaches to quantum information processing (QIP) aim to capitalize on the strengths of disparate quantum technologies to realize a system whose capabilities exceed those of any single experimental platform. At the University of Wisconsin, we are working toward integration of a fast superconducting quantum processor with a stable, long-lived quantum memory based on trapped neutral atoms. Here we describe the development of a quantum interface between superconducting thin-film cavity circuits and trapped Rydberg atoms, the key technological obstacle to realization of superconductor-atom hybrid QIP. Specific accomplishments to date include development of a theoretical protocol for high-fidelity state transfer between the atom and the cavity; fabrication and characterization of high- Q superconducting cavities with integrated trapping electrodes to enhance zero-point microwave fields at a location remote from the chip surface; and trapping and Rydberg excitation of single atoms within 1 mm of the cavity. We discuss the status of experiments to probe the strong coherent coupling of single Rydberg atoms and the superconducting cavity. Supported by ARO under contract W911NF-16-1-0133.

  15. High temperature superconductor current leads

    International Nuclear Information System (INIS)

    Zeimetz, B.; Liu, H.K.; Dou, S.X.

    1996-01-01

    Full text: The use of superconductors in high electrical current applications (magnets, transformers, generators etc.) usually requires cooling with liquid Helium, which is very expensive. The superconductor itself produces no heat, and the design of Helium dewars is very advanced. Therefore most of the heat loss, i.e. Helium consumption, comes from the current lead which connects the superconductor with its power source at room temperature. The current lead usually consists of a pair of thick copper wires. The discovery of the High Temperature Superconductors makes it possible to replace a part of the copper with superconducting material. This drastically reduces the heat losses because a) the superconductor generates no resistive heat and b) it is a very poor thermal conductor compared with the copper. In this work silver-sheathed superconducting tapes are used as current lead components. The work comprises both the production of the tapes and the overall design of the leads, in order to a) maximize the current capacity ('critical current') of the superconductor, b) minimize the thermal conductivity of the silver clad, and c) optimize the cooling conditions

  16. Hybrid molecule/superconductor assemblies

    International Nuclear Information System (INIS)

    McDevitt, J.T.; Haupt, S.G.; Riley, D.R.; Zhao, J.; Zhou, J.P., Jones, C.

    1993-01-01

    The fabrication of electronic devices from molecular materials has attracted much attention recently. Schottky diodes, molecular transistors, metal-insulator-semiconductor diodes, MIS field effect transistors and light emitting diodes have all been prepared utilizing such substances. The active elements in these devices have been constructed by depositing the molecular phase onto the surface of a metal, semiconductor or insulating substrate. With the recent discovery of high temperature superconductivity, new opportunities now exist for the study of molecule/superconductor interactions as well as for the construction of novel hybrid molecule/superconductor devices. In this paper, methods for preparing the initial two composite molecule/semiconductor devices will be reported. Consequently, light sensors based on dye-coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor microbridges will be discussed. Moreover, molecule/superconductor energy and electron transfer phenomena will be illustrated also for the first time

  17. Model films of cellulose. I. Method development and initial results

    NARCIS (Netherlands)

    Gunnars, S.; Wågberg, L.; Cohen Stuart, M.A.

    2002-01-01

    This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated

  18. Development of A Thin Film Crystalline Silicon Solar Cell

    International Nuclear Information System (INIS)

    Sopori, B.; Chen, W.; Zhang, Y.

    1998-01-01

    A new design for a single junction, thin film Si solar cell is presented. The cell design is compatible with low-temperature processing required for the use of a low-cost glass substrate, and includes effective light trapping and impurity gettering. Elements of essential process steps are discussed

  19. Development of Chitosan Acetate Films for Transdermal Delivery of ...

    African Journals Online (AJOL)

    Methods: Chitosan acetate was chemically modified with acetaldehyde and the solution was prepared with 1 % acetic acid, in which was dissolved propranolol hydrochloride, was cast as films in Petri dish and characterised by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and ...

  20. Development of Oral Fast-Disintegrating Levothyroxine Films for ...

    African Journals Online (AJOL)

    physical appearance, thickness, weight variation, folding endurance, drug content uniformity, The effect ... In children, hypothyroidism leads to delay in growth and .... rapid and convenient drug delivery technology for the pediatric patients. Table 3: Physical characteristics of films. Batch. Drug content. (%). Folding endurance.

  1. Tl Cuprate Superconductors Studied by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, R. P. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099 (United States); Siegal, M. P. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, NM 87185-1421 (United States); Ren, Z. F. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Lao, J. Y. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States); Wang, J. H. [Department of Chemistry, State University of New York, Buffalo, NY 14260-3000 (United States)

    1999-07-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-{delta} are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-{delta} and TlBa2CaCu2O7-{delta}, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society.

  2. Tl Cuprate Superconductors Studied by XPS

    International Nuclear Information System (INIS)

    Vasquez, R. P.; Siegal, M. P.; Overmyer, D. L.; Ren, Z. F.; Lao, J. Y.; Wang, J. H.

    1999-01-01

    XPS measurements on epitaxial thin films of the Tl cuprate superconductors Tl2Ba2CaCu2O8, Tl2Ba2Ca2Cu3O10, and Tl0.78Bi0.22Ba0.4Sr1.6Ca2Cu3O9-δ are presented. These data, together with previous measurements in this lab on Tl2Ba2CuO6-δ and TlBa2CaCu2O7-δ, comprise a comprehensive data set for comparison of Tl cuprates in which the number of Tl-O and Cu-O layers, and hence the chemical and electronic properties, vary. (c) 2000 American Vacuum Society

  3. The Goettingen high-Tc superconductivity research pool: the effects of structure and structural defects on the performance of high-Tc superconductors. Final reports

    International Nuclear Information System (INIS)

    1992-02-01

    The compilation presents the final reports prepared by the various teams of the Goettingen research pool for high-Tc superconductivity. The reports are entitled: Structure and phase transition in high-Tc superconductors (Krebs/Freyhardt). Preparation and critical properties of high-Tc superconductors (Freyhardt/Heinemann/Zimmermann). EMC measurements in high-Tc superconductors (Bormann/Noelting). Phase analysis of the various phases observed in the preparation of high-Tc superconductors (Faupel/Hehenkamp). Positron annihilation in high-Tc superconductors (Hehenkamp). Preparation and characterization of thin films consisting of superconducting oxide ceramics (v. Minnigerode/Samwer). High-Tc superconductivity in monocrystals (Winzer/Beuermann). Microwave conductivity in high-Tc superconductors (Helberg). High-resolution structural analyses in high-Tc superconductors (Kupcik/Bente). Synthesis, structural analyses and spectroscopy of high-Tc superconductors (Bente). Synthesis, monocrystal growing, crystal structure of high-Tc superconductors (Schwarzmann). Ion-beam-aided studies in high-Tc superconductors (Uhrmacher). (orig./MM) [de

  4. Superconducting thin films of Bi-Sr-Ca-Cu-O by laser ablation

    International Nuclear Information System (INIS)

    Bedekar, M.M.

    1992-01-01

    The discovery of a new class of copper oxide superconductors has led to the development of three major systems that exhibit superconducting properties. The Bi-Sr-Ca-Cu-O superconductors offer intrinsic advantages due to the high T c , chemical inertness and tolerance for a range of compositions. However, thin film research on these materials has progressed more slowly than the other cuprate systems. This dissertation examines the film growth, by laser ablation, of the Bi-Sr-Ca-Cu-O superconductors and the effect of the deposition parameters such as the laser target interaction, substrate temperature, target to substrate distance, deposition and cooling pressure, target type and processing and the substrate type. CO 2 laser ablation was shown to give rise to a non-stoichiometric material transfer due to the low fluences and long pulse lengths. In situ superconducting thin films with T c(0) 's of 76 K could be deposited using the KrF laser at substrate temperatures of 5 degrees C to 20 degrees C below phases. Lower temperatures gave rise to a mixture of 2201 and glassy phases. An increase in the target to substrate distance led to a deterioration of the electrical and structural properties of the films due to a decrease in the energy for film formation. A maximum in T c(0) was observed at 450 mtorr as the deposition pressure was varied between 200 to 700 mtorr. Optimum oxygen incorporation could be achieved by cooling the films in high oxygen pressures and the best films were obtained with 700 torr cooling pressure. The oxygen deficiency of the hot pressed targets led to inferior properties compared to the conventionally sintered targets. The microwave surface resistance of the films measured at 35 GHz showed an onset at 80 K and dropped below that of copper at 30 K. The study of the laser ablation process in this system revealed the presence of a stoichiometric forward directed component and a diffuse evaporation component

  5. Vortex and characteristics of prestrained type-II deformable superconductors under magnetic fields

    International Nuclear Information System (INIS)

    Ma, Zeling; Wang, Xingzhe; Zhou, Youhe

    2016-01-01

    Highlights: • A numerical investigation of magnetic vortex dynamics of a deformable superconductor with prestrains is presented. • The prestrain has a remarkable influence on the magnetic vortex distribution and dynamics. • The different prestrains, i.e., pre-given compression and tension strains, result in dissimilar characteristics. • The energy density and spectrum in the deformable superconductor are demonstrated. - Abstract: Based on the time-dependent Ginzburg–Landau (TDGL) theory and the linear deformation theory, we present a numerical investigation of magnetic vortex characteristics of a type-II deformable superconductor with prestrain. The effect of prestrain on the wave function, vortex dynamics and energy density of a superconducting film is analyzed by solving the nonlinear TDGL equations in the presence of magnetic field. The results show that the prestrain has a remarkable influence on the magnetic vortex distribution and the vortex dynamics, as well as value of wave function of the superconductor. The different prestrains, i.e., pre-given compression and tension strains, result in dissimilar characteristics on a half-plane of deformable superconductor in an applied magnetic field, and the vortex distribution and entrance in a two dimensional superconducting film. The studies demonstrated that the compression prestrain may speed up the vortexes entering into the region of the superconducting film and increases the vortex number in comparison with those of free-prestrain case, while the tension prestrain shows the reversal features. The energy density and spectrum in the superconductor are further demonstrated numerically and discussed. The present investigation is an attempt to give insight into the superconductivity and electromagnetic characteristics taking into account the elastic deformation in superconductors.

  6. Development of Epitaxial GaN Films for RF Communications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective of this SBIR is to develop epitaxial GaN films with threading dislocation density less than 10^6 cm^-2. We propose an innovative approach...

  7. An approach to finding teaching moments on families and child development in Disney films.

    Science.gov (United States)

    Guerrero, Anthony P S

    2015-04-01

    In the interest of finding "teaching moments in film" for psychiatric education and education on child development, the author describes an approach to analyzing Disney--and potentially other children's films--based on specifically observing family structure at the beginning and ending of the story, developmental stage and gender of the protagonist, the developmental crisis, and the external change agent and/or stressor. The author considered a convenience sample of ten popular Disney films. A wide variety of family structures and developmental stages and challenges were observed in the reviewed films. A matrix approach such as the one illustrated may help psychiatric educators to select effective teaching moments from Disney and other children's films.

  8. Development and characterization of edible films based on mucilage of Opuntia ficus-indica (L.).

    Science.gov (United States)

    Espino-Díaz, Miguel; de Jesús Ornelas-Paz, J; Martínez-Téllez, Miguel A; Santillán, Carlos; Barbosa-Cánovas, Gustavo V; Zamudio-Flores, Paul B; Olivas, Guadalupe I

    2010-08-01

    could represent a good option for the development of edible films in countries where nopal is highly produced at low cost, constituting a processing alternative for nopal.

  9. Development and initial evaluation of a spectral microdensitometer for analysing radiochromic films

    International Nuclear Information System (INIS)

    Lee, K Y; Fung, K L; Kwok, C S

    2004-01-01

    Radiation dose deposited on a radiochromic film is considered as a dose image. A precise image extraction system with commensurate capabilities is required to measure the transmittance of the image and translate it to radiation dose. This paper describes the development of a spectral microdensitometer which has been designed to achieve this goal under the conditions of (a) the linearity and sensitivity of the dose response curve of the radiochromic film being highly dependent on the wavelength of the analysing light, and (b) the inherent high spatial resolution of the film. The microdensitometer consists of a monochromator which provides an analysing light of variable wavelength, a film tray on a high-precision scanning stage, a transmission microscope coupled to a thermoelectrically cooled CCD camera, a microcomputer and corresponding interfaces. The measurement of the transmittance of the radiochromic film is made at the two absorption peaks with maximum sensitivities. The high spatial resolution of the instrument, of the order of micrometres, is achieved through the use of the microscope combined with a measure-and-step technique to cover the whole film. The performance of the instrument in regard to the positional accuracy, system reproducibility and dual-peak film calibration was evaluated. The results show that the instrument fulfils the design objective of providing a precise image extraction system for radiochromic films with micrometre spatial resolution and sensitive dose response

  10. Development and initial evaluation of a spectral microdensitometer for analysing radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K Y [Department of Optometry and Radiography, Hong Kong Polytechnic University, Hong Kong (China); Fung, K L [Department of Optometry and Radiography, Hong Kong Polytechnic University, Hong Kong (China); Kwok, C S [Department of Radioimmunotherapy, City of Hope National Medical Centre, Duarte, CA 91010 (United States)

    2004-11-21

    Radiation dose deposited on a radiochromic film is considered as a dose image. A precise image extraction system with commensurate capabilities is required to measure the transmittance of the image and translate it to radiation dose. This paper describes the development of a spectral microdensitometer which has been designed to achieve this goal under the conditions of (a) the linearity and sensitivity of the dose response curve of the radiochromic film being highly dependent on the wavelength of the analysing light, and (b) the inherent high spatial resolution of the film. The microdensitometer consists of a monochromator which provides an analysing light of variable wavelength, a film tray on a high-precision scanning stage, a transmission microscope coupled to a thermoelectrically cooled CCD camera, a microcomputer and corresponding interfaces. The measurement of the transmittance of the radiochromic film is made at the two absorption peaks with maximum sensitivities. The high spatial resolution of the instrument, of the order of micrometres, is achieved through the use of the microscope combined with a measure-and-step technique to cover the whole film. The performance of the instrument in regard to the positional accuracy, system reproducibility and dual-peak film calibration was evaluated. The results show that the instrument fulfils the design objective of providing a precise image extraction system for radiochromic films with micrometre spatial resolution and sensitive dose response.

  11. Effects of developer exhaustion on DFL Contrast FV-58 and Kodak Insight dental films.

    Science.gov (United States)

    de Carvalho, Fabiano Pachêco; da Silveira, M M F; Frazão, M A G; de Santana, S T; dos Anjos Pontual, M L

    2011-09-01

    The aim of this study was to compare the properties of the DFL Contrast FV-58 F-speed film (DFL Co., Rio de Janerio, Brazil) with the Kodak Insight E/F speed film (Eastman Kodak, Rochester, NY) in fresh and exhausted processing solutions. The parameters studied were the speed, average gradient and latitude. Five samples of each type of film were exposed under standardized conditions over 5 weeks. The films were developed in fresh and progressively exhausted processing solutions. Characteristic curves were constructed from values of optical density and radiation dose and were used to calculate the parameters. An analysis of variance was performed separately for film type and time. DFL Contrast FV-58 film has a speed and average gradient that is significantly higher than Insight film, whereas the values of latitude are lower. Exhausted processing solutions were not significant in the parameters studied. DFL Contrast FV-58 film has stable properties when exhausted manual processing solutions are used and can be recommended for use in dental practice, contributing to dose reduction.

  12. Development and characterization of carrageenan/grapefruit seed extract composite films for active packaging.

    Science.gov (United States)

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-07-01

    Carrageenan-based antimicrobial films were developed by incorporation of grape fruit seed extract (GSE) at different concentration into the polymer using a solvent casing method and their physical, mechanical, and antimicrobial properties were examined. The carrageenan/GSE composite films appeared yellowish tint due to the polyphenolic compounds in the GSE. SEM analysis showed rough surface with sponge like structures on the cross section of the films. FT-IR results indicated at GSE had good compatibility with carrageenan. The amorphous structure of polymer films was not changed by the incorporation of GSE. But, the addition of GSE increased moisture content, water vapor permeability, and surface hydrophilicity of the films. The tensile strength and elastic modulus decreased with increasing content of GSE, however, the elongation at break increased significantly up to 6.6μg/mL of GSE then decreased thereafter. Thermal stability of the films was not influenced by GSE incorporation. The carrageenan/GSE composite films exhibited great antibacterial activity against food borne pathogens. These results suggest that the carrageenan-based composite films have a high potential for being used as an antimicrobial or active food packaging applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Development of ecofriendly bionanocomposite: Whey protein isolate/pullulan films with nano-SiO2.

    Science.gov (United States)

    Hassannia-Kolaee, Mahbobeh; Khodaiyan, Faramarz; Pourahmad, Rezvan; Shahabi-Ghahfarrokhi, Iman

    2016-05-01

    During the past decade, the limitation of petroleum based polymers, the high price of oil, and the environmental concern were attracted the attention of researchers to develop biobased polymers. The composition of different biopolymers and the reinforcement with nano filler are common methods to improve the drawbacks of biopolymers. In this study whey protein isolate/pullulan (WPI/PUL) films contain 1%, 3%, and 5% (w/w) nano-SiO2 (NS) were prepared by a casting method. Tensile strength of nanocomposite films increased after increasing NS content, but elongation at break decreased, simultaneously. Water absorption, moisture content, solubility in water improved in the wake of increasing NS content because NS increase the cohesiveness of the polymer matrix and improved the barrier and water resistance properties of the films. water vapor permeability of film specimens decreased by increasing NS content. Uniform distribution of NS into polymer matrix was confirmed by scanning electron microscopy (SEM). XRD pattern and thermal analysis revealed increasing crystallinity and increasing Tg of film specimens with increasing NS content, respectively. According to our result WPI/PUL/NS films possess potential to be used as environment friendly packaging films to improve shelf life of food and can be used as promising alternative to petroleum based packaging films. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Pharmaceutical films made from the waste material from the preparation of propolis extracts: development and characterization

    Directory of Open Access Journals (Sweden)

    Lucas de Alcântara Sica de Toledo

    2015-12-01

    Full Text Available abstract This study investigated the development and characterized the physicochemical properties of films obtained from by-products (BP from the preparation of propolis extracts. Films were produced in the presence and absence of a polymeric adjuvant (gelatin or ethylcellulose and propylene glycol by a solvent casting method. Density, surface topography by scanning electron microscopy, mechanical properties (folding endurance, tensile strength and percentage elongation, water vapour permeability (WVP, moisture uptake capacity, thermogravimetry, differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR were determined. The films were a transparent, light greenish-yellow colour, with a uniform surface, and were flexible and easy to handle. The thickness and density of the preparations indicated that the compounds were homogeneously dispersed throughout the film. Mechanical properties were influenced by the film composition; films containing gelatin were more resistant to stress, while those containing ethylcellulose were more flexible. Increasing the adjuvant concentration decreased the elasticity and the rupture resistance, but increased the moisture uptake capacity and WVP of the formulations. BP was thermally stable as were the films. FTIR tests suggested interactions between BP and the adjuvants. This work could contribute to the utilization of BP to prepare films for food and pharmaceutical uses

  15. Screen printed Y and Bi-based superconductors

    Science.gov (United States)

    Haertling, Gene H.; Hsi, Chi-Shiung

    1992-01-01

    High T(sub c) superconducting thick film was prepared by screen printing process. Y-based (YBa2Cu3O(7 - x)) superconducting thick films were printed on 211/Al2O3, SNT/Al2O3, and YSZ substrates. Because of poor adhesion of the superconducting thick films to 211/Al2O3 and SNT/Al2O3 substrates, relatively low T(sub c) and J(sub c) values were obtained from the films printed on these substrates. Critical temperatures of YBa2Cu3O(7 - x) thick films deposited on 211/Al2O3 and SNT/Al2O3 substrates were about 80 K. The critical current densities of these films were less than 2 A/cm(exp 2). Higher T(sub c) and J(sub c) films were printed on the YSZ substrates; T(sub c) = 86.4 K and J(sub c) = 50.4 A/cm(exp 2). Multiple lead samples were also prepared on the YSZ substrates. These showed lower T(sub c) and J(sub c) values than plain samples. The heat treatment conditions of the multiple lead samples are still under investigation. Bi-based superconductor thick films have been obtained so far. Improving the superconducting properties of the BSCCO screen printed thick films will be emphasized in future work.

  16. Signature of magnetic-dependent gapless odd frequency states at superconductor / ferromagnet interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Jason [Department of Materials Science, 27 Charles Babbage Road, Cambridge, CB30FS (United Kingdom)

    2015-07-01

    The theory of superconductivity developed by Bardeen, Cooper, and Schrieffer (BCS) explains the stabilisation of electron pairs into a spin-singlet, even frequency, state by the formation of an energy gap below which the density of states (DoS) is zero. At a superconductor interface with an inhomogeneous ferromagnet, a gapless odd frequency superconducting state is predicted in which the Cooper pairs are in a spin-triplet state. Although indirect evidence for such a state has been obtained, the gap structure and pairing symmetry have not so far been determined. In this talk I will present scanning tunnelling spectroscopy of Nb superconducting films proximity coupled to epitaxial Ho. These measurements reveal pronounced changes to the Nb sub-gap superconducting DoS on driving the Ho through a metamagnetic transition from a helical antiferromagnetic to a homogeneous ferromagnetic state for which a BCS-like gap is recovered. The results verify odd frequency spin-triplet superconductivity at superconductor / inhomogeneous magnet interfaces.

  17. Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour [Radiation Application Research School, Nuclear Science and Research Institute, North Kargar Ave., Tehran (Iran, Islamic Republic of)

    2009-07-01

    Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

  18. Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

    International Nuclear Information System (INIS)

    Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour

    2009-01-01

    Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

  19. Development of thin-film Si HYBRID solar module

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Akihiko; Gotoh, Masahiro; Sawada, Toru; Fukuda, Susumu; Yoshimi, Masashi; Yamamoto, Kenji; Nomura, Takuji [Kaneka Corporation, 2-1-1, Hieitsuji, Otsu, Shiga 520-0104 (Japan)

    2009-06-15

    The device current-voltage (I-V) characteristics of thin-film silicon stacked tandem solar modules (HYBRID modules), consisting of a hydrogenated amorphous silicon (a-Si:H) cell and a thin-film crystalline silicon solar cell ({mu}c-Si), have been investigated under various spectral irradiance distributions. The performance of the HYBRID module varied periodically in natural sunlight due to the current-limiting property of the HYBRID module and the environmental effects. The behavior based on the current-limiting property was demonstrated by the modelling of the I-V curves using the linear interpolation method for each component cell. The improvement of the performance for the HYBRID module in natural sunlight will also be discussed from the viewpoint of the device design of the component cells. (author)

  20. Film and the Representation of the Poverty. Touristic Mobilities in Developing countries

    Directory of Open Access Journals (Sweden)

    Donatella Privitera

    2015-03-01

    Full Text Available In recent times, film tourism has become one of the fastest-growing niche tourism segments in the world. Many films and audiovisual works analyse various representations of social life including the poverty and degradation of the poorest urban areas of the developing world. Films are seen as being responsible for the increased interest in the favela in Brazil, the townships of South Africa, and the slums in India. The development of the favela into a tourist destination is seen as part of the so-called reality tour phenomenon and of the global circulation of the favela as a trademark. This paper evaluates poverty representations that induced tourism in developing countries. Our selection is drawn primarily from popular films that have been influential in the global north such as City of God (2002 and Slumdog Millionaire (2008.

  1. Development of microforming process combined with thin film transfer printing

    Directory of Open Access Journals (Sweden)

    Koshimizu Kazushi

    2015-01-01

    Full Text Available Microforming receives a lot of attentions in the recent years due to the increased use of microparts in electronics and medical sectors. For the further functionalization of these micro devices, high functional surface with noble metals are strongly required for the devices in bio- and medical fields, such as bio-sensors. To realize the submillimeter structure of metal foils and micro to nanometer structures in one forming process, the present study proposes a combined process of microforming for metal foils and transfer printing of gold (Au thin films. To clarify the availability of the proposed combined process, transferability of Au thin films under micro bulging deformation are investigated. 0.1 mm-thick pure titanium (Ti foils and 100 nm-thick Au films were used as blank and functional materials, respectively. The forming tests of the proposed process were conducted. With increasing strain of Ti foils, Au TP areas increase. By this experiment, it’s confirmed that the hydrogen reduction of oxidation layers and the strain of Ti foil are significant factor for Au TP on Ti foils.

  2. TECHNICAL TRAINING SEMINAR: High Temperature Superconductors: Progress and Issues

    CERN Multimedia

    Davide Vitè

    2002-01-01

    Monday 24 June from 14:30 to 15:30 - Training Centre Auditorium - bldg. 593-11 High Temperature Superconductors: Progress and Issues Prof. Jan Evetts / UNIVERSITY OF CAMBRIDGE, Department of Materials Science and Metallurgy, UK Grappling with grain boundaries: Current transport processes in granular High Temperature Superconductors (HTS) The development of High Temperature Superconductors, seen from a materials scientist's point of view, is relevant to the superconductivity community at CERN: their possible high current applications can include high performance magnets for future accelerators. There is an urgent need to develop a quantitative description of HTS conductors in terms of their complex anisotropy, inhomogeneity and dimensionality. This is essential both for the practical specification of a conductor and for charting routes to conductor optimisation. The critical current, the n-value, dissipation and quenching characteristics are amongst most important parameters that make up an engineering specifi...

  3. Energy-gap spectroscopy of superconductors using a tunneling microscope

    International Nuclear Information System (INIS)

    Le Duc, H.G.; Kaiser, W.J.; Stern, J.A.

    1987-01-01

    A unique scanning tunneling microscope (STM) system has been developed for spectroscopy of the superconducting energy gap. High-resolution control of tunnel current and voltage allows for measurement of superconducting properties at tunnel resistance levels 10 2 --10 3 greater than that achieved in prior work. The previously used STM methods for superconductor spectroscopy are compared to those developed for the work reported here. Superconducting energy-gap spectra are reported for three superconductors, Pb, PbBi, and NbN, over a range of tunnel resistance. The measured spectra are compared directly to theory

  4. Development of Biopolymer Composite Films Using a Microfluidization Technique for Carboxymethylcellulose and Apple Skin Particles

    Directory of Open Access Journals (Sweden)

    Inyoung Choi

    2017-06-01

    Full Text Available Biopolymer films based on apple skin powder (ASP and carboxymethylcellulose (CMC were developed with the addition of apple skin extract (ASE and tartaric acid (TA. ASP/CMC composite films were prepared by mixing CMC with ASP solution using a microfluidization technique to reduce particle size. Then, various concentrations of ASE and TA were incorporated into the film solution as an antioxidant and an antimicrobial agent, respectively. Fourier transform infrared (FTIR, optical, mechanical, water barrier, and solubility properties of the developed films were then evaluated to determine the effects of ASE and TA on physicochemical properties. The films were also analyzed for antioxidant effect on 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and antimicrobial activities against Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, and Shigella flexneri. From the results, the ASP/CMC film containing ASE and TA was revealed to enhance the mechanical, water barrier, and solubility properties. Moreover, it showed the additional antioxidant and antimicrobial properties for application as an active packaging film.

  5. Insect-resistant food packaging film development using cinnamon oil and microencapsulation technologies.

    Science.gov (United States)

    Kim, In-Hah; Han, Jaejoon; Na, Ja Hyun; Chang, Pahn-Sik; Chung, Myung Sub; Park, Ki Hwan; Min, Sea C

    2013-02-01

    Insect-resistant films containing a microencapsulated insect-repelling agent were developed to protect food products from the Indian meal moth (Plodia interpunctella). Cinnamon oil (CO), an insect repelling agent, was encapsulated with gum arabic, whey protein isolate (WPI)/maltodextrin (MD), or poly(vinyl alcohol) (PVA). A low-density polyethylene (LDPE) film was coated with an ink or a polypropylene (PP) solution that incorporated the microcapsules. The encapsulation efficiency values obtained with gum arabic, WPI/MD, and PVA were 90.4%, 94.6%, and 80.7%, respectively. The films containing a microcapsule emulsion of PVA and CO or incorporating a microcapsule powder of WPI/MD and CO were the most effective (P packaging for food products. The insect-repelling effect of cinnamon oil incorporated into LDPE films was more effective with microencapsulation. The system developed in this research with LDPE film may also be extended to other food-packaging films where the same coating platform can be used. This platform is interchangeable and easy to use for the delivery of insect-repelling agents. The films can protect a wide variety of food products from invasion by the Indian meal moth. © 2013 Institute of Food Technologists®

  6. A look-up table for fully developed film-boiling heat transfer

    International Nuclear Information System (INIS)

    Groeneveld, D.C.; Leung, L.K.H.; Vasic, A.Z.; Guo, Y.J.; Cheng, S.C.

    2003-01-01

    An improved look-up table for film-boiling heat-transfer coefficients has been derived for steam-water flow inside vertical tubes. Compared to earlier versions of the look-up table, the following improvements were made: - The database has been expanded significantly. The present database contains 77,234 film-boiling data points obtained from 36 sources. - The upper limit of the thermodynamic quality range was increased from 1.2 to 2.0. The wider range was needed as non-equilibrium effects at low flows can extend well beyond the point where the thermodynamic quality equals unity. - The surface heat flux has been replaced by the surface temperature as an independent parameter. - The new look-up table is based only on fully developed film-boiling data. - The table entries at flow conditions for which no data are available is based on the best of five different film-boiling prediction methods. The new film-boiling look-up table predicts the database for fully developed film-boiling data with an overall rms error in heat-transfer coefficient of 10.56% and an average error of 1.71%. A comparison of the prediction accuracy of the look-up table with other leading film-boiling prediction methods shows that the look-up table results in a significant improvement in prediction accuracy

  7. Ultrasound treated potato peel and sweet lime pomace based biopolymer film development.

    Science.gov (United States)

    Borah, Purba Prasad; Das, Pulak; Badwaik, Laxmikant S

    2017-05-01

    Treatment and management of food processing waste is a major challenge for food industry. Potato processing industry generates tremendous amount of peel and consider it as zero valued waste. Again, pomace generated after juice extraction from sweet lime pulp is considered as waste and not properly utilized. Whereas these waste could be utilized for the development of biodegradable packaging film to overcome environmental issues. Composite films were prepared with varying proportion of potato peel powder (PP) and sweet lime pomace (SLP) in the ratio of 0:1(A), 0.5:1(B), 1:1(C), 1:0.5(D), 1:0(E) with an ultrasound treatment of 45min, and 0:1(F), 0.5:1(G), 1:1(H), 1:0.5(I), 1:0(J) with an ultrasound treatment of 60min. Ultrasound was applied for 45 and 60min to film forming solutions to break down biopolymer particles small enough to form a film. All the films were analyzed for their barrier and mechanical properties. It was observed that increasing ultrasound treatment times gives better result in film properties and less PP content also gives better film properties, from these observations film G prepared with 0.5:1 (PP:SLP) showed better characteristics among all other films. Water vapor permeability, moisture absorption, water solubility, breakage strength and elongation capacity of G film were reported as 7.25×10 -9 g/Pahm, 12.88±0.348%, 38.92±0.702%, 242.01±3.074g and 7.61±0.824mm respectively. However, thermal decomposition for film G took place above 200°C. The film forming solution of selected G film, added with clove essential oil (1.5%) as an antimicrobial agent was wrapped on bread and stored it for 5days. The film was successful in lowering the weight loss, reducing the hardness and inhibition of surface microbial load from bread sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Investigation on the bisoliton mechanism of high-temperature superconductors

    International Nuclear Information System (INIS)

    Zhang Lingyun; Li Bozang; Pu Fucho; Lin Jiatih

    1996-01-01

    Microscopic parameters in the Davydov model are calculated on the basis of the bisoliton idea. The energy gap is obtained from combining the condition for the solution of Davydov's equation with the condensation energy of the superconductive state in zero field, and some characteristic parameters of high-temperature superconductors such as coherence length, penetration depth, and density of critical current for a thin film in weak magnetic field are given. It is also proved that lattice displacement in Davydov's equation satisfies the φ 4 field form. The critical temperature and the coefficient of linear specific heat of high-temperature superconductors are studied from the statistics of lattice kinks. The agreement between theoretical and experimental values for YBaCuO oxide ceramics suggests that the bisoliton model gives a reasonable explanation of high-temperature superconductivity. (orig.)

  9. Nanostructuring superconductors by ion beams: A path towards materials engineering

    Energy Technology Data Exchange (ETDEWEB)

    Gerbaldo, Roberto; Ghigo, Gianluca; Gozzelino, Laura; Laviano, Francesco [Department of Applied Science and Technology, Politecnico di Torino c.so Duca degli Abruzzi 24, 10129 Torino, Italy and INFN Sez. Torino, via P. Giuria 1, 10125 Torino (Italy); Amato, Antonino; Rovelli, Alberto [INFN Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Cherubini, Roberto [INFN Laboratori Nazionali di Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy)

    2013-07-18

    The paper deals with nanostructuring of superconducting materials by means of swift heavy ion beams. The aim is to modify their structural, optical and electromagnetic properties in a controlled way, to provide possibility of making them functional for specific applications. Results are presented concerning flux pinning effects (implantation of columnar defects with nanosize cross section to enhance critical currents and irreversibility fields), confined flux-flow and vortex guidance, design of devices by locally tailoring the superconducting material properties, analysis of disorder-induced effects in multi-band superconductors. These studies were carried out on different kinds of superconducting samples, from single crystals to thin films, from superconducting oxides to magnesium diboride, to recently discovered iron-based superconductors.

  10. Ferromagnet / superconductor oxide superlattices

    Science.gov (United States)

    Santamaria, Jacobo

    2006-03-01

    The growth of heterostructures combining oxide materials is a new strategy to design novel artificial multifunctional materials with interesting behaviors ruled by the interface. With the (re)discovery of colossal magnetoresistance (CMR) materials, there has been renewed interest in heterostructures involving oxide superconductors and CMR ferromagnets where ferromagnetism (F) and superconductivity (S) compete within nanometric distances from the interface. In F/S/F structures involving oxides, interfaces are especially complex and various factors like interface disorder and roughness, epitaxial strain, polarity mismatch etc., are responsible for depressed magnetic and superconducting properties at the interface over nanometer length scales. In this talk I will focus in F/S/F structures made of YBa2Cu3O7 (YBCO) and La0.7Ca0.3MnO3 (LCMO). The high degree of spin polarization of the LCMO conduction band, together with the d-wave superconductivity of the YBCO make this F/S system an adequate candidate for the search of novel spin dependent effects in transport. We show that superconductivity at the interface is depressed by various factors like charge transfer, spin injection or ferromagnetic superconducting proximity effect. I will present experiments to examine the characteristic distances of the various mechanisms of superconductivity depression. In particular, I will discuss that the critical temperature of the superconductor depends on the relative orientation of the magnetization of the F layers, giving rise to a new giant magnetoresistance effect which might be of interest for spintronic applications. Work done in collaboration with V. Peña^1, Z. Sefrioui^1, J. Garcia-Barriocanal^1, C. Visani^1, D. Arias^1, C. Leon^1 , N. Nemes^2, M. Garcia Hernandez^2, S. G. E. te Velthuis^3, A. Hoffmann^3, M. Varela^4, S. J. Pennycook^4. Work supported by MCYT MAT 2005-06024, CAM GR- MAT-0771/2004, UCM PR3/04-12399 Work at Argonne supported by the Department of Energy, Basic

  11. Topological Insulators and Superconductors for Innovative Devices

    Science.gov (United States)

    2015-03-20

    Final 3. DATES COVERED (From - To) 20120321 - 20150320 4. TITLE AND SUBTITLE Topological insulators and superconductors for innovative...locking, which hold promise for various innovative devices. Similarly, topological superconductors are associated with exotic surface states, which...298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 Final Report Title: Topological Insulators and Superconductors for Innovative Devices

  12. Superconductors: The long road ahead

    International Nuclear Information System (INIS)

    Foner, S.; Orlando, T.P.

    1988-01-01

    Before the discovery of high-temperature superconductors, progress in superconductivity was measured by quite small increases in critical temperature, often of less than one degree. Today, there is no reason to believe that the dramatic leaps in critical temperature inaugurated by superconducting ceramics are over. Researchers may find new high-temperature superconducting materials with less severe technical limitations than the ceramics we know today. And if the day ever comes when a superconductor can be reliably manufactured to operate effectively at room temperature, then superconductors will be incorporated in a broad range of everyday household devices - motors, appliances, even children's toys - with a large consumer market. High-temperature superconductors may also cause us to extensively revise our traditional theories about how superconductivity works. Should it run out that superconductivity in ceramics involves new physical mechanisms, then these mechanisms could lead to applications never considered before. The recent discoveries have already reinvigorated superconductivity research. What was once largely the domain of a relatively small group of scientists has become a genuinely multidisciplinary realm. Now physicists, materials scientists, chemists, metallurgists, ceramists, and solid-state electronics engineers are all focusing on superconductivity. The cross-fertilization of these disciplines should contribute to further discoveries of importance to the practical application of superconductors

  13. Electronic components with yttrium- and bismuth-based high-Tc superconductors

    International Nuclear Information System (INIS)

    Daginnus, M.; Guettler, B.

    1992-01-01

    This project investigates the fabrication of microwave components by use of high-Tc superconductors. Detailed descriptions are given of the manufacturing and use of active Y-Ba-Cu-O components. The surface resistance of thin films used in high-quality passive microwave components such as resonators and filters is measured and optimized. (orig./MM) [de

  14. Low-temperature dependence of the optical conductivity in superconductor MgB2

    International Nuclear Information System (INIS)

    Shahzamanian, M.A.; Yavary, H.; Moarrefi, M.

    2005-01-01

    The real part of the optical conductivity is calculated by using the Kubo formula approach, and in the framework of the two-bands model. It is shown that a single-gap model is insufficient to describe the optical behavior of superconductor MgB 2 film, but the two-gap model with different symmetries is sufficient to explain the experimental results

  15. Far infrared spectroscopy of high-Tc superconductors at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Perkowitz, S.; Williams, G.P.

    1989-01-01

    This paper reports the first far infrared transmission spectra for micron-thick films of high-T c rare-earth superconductors such as DyBaCuO, with implications for the superconducting gap. Spectra were obtained at Brookhaven's National Synchrotron Light Source, a new high-intensity, broad-band millimeter to infrared source. The National Synchrotron Light Source at Brookhaven National Laboratory, known for powerful X-ray and UV output, is also a high-intensity (10 to 1000 times above a black body), high-brightness (intensity per solid angle), broad-band, picosecond, millimeter to infrared source. These features make it valuable for far-infrared condensed matter experiments, especially those in highly absorbing or extremely small systems. A first application has been to measure very small infrared transmissions through thick bulk-like high-T c superconducting films. Preliminary measurements through films of the conventional superconductor Nb 3 Ge established techniques. These were followed by the first measurements (to the author's knowledge) through micron-thick films of high-T c rare-earth superconductors such as DyBaCuO over 10-300 cm -1 , which includes the superconducting gap according to BCS or moderately strong-coupled theory. The authors discuss the transmission evidence bearing on the existence of a gap and other important features of high-T c superconductors, and describe the synchrotron and instrumentation features which make possible these unusual measurements

  16. Visual development as a tool for storytelling in animated feature films

    OpenAIRE

    Moura, João Garcia de Lima de

    2014-01-01

    This dissertation aims to study and deepen the understanding of Visual Development and the way it is used towards storytelling. In animated feature and short films every element is studied and created in order to help the viewer understand the story. We will study concepts like color and light to understand how they are used in order to create an emotional connection between the animation and the viewer. The animated film ‘Beauty and the Beast’ (1991) from Walt Disney studio...

  17. Development of tailored indigenous marine consortia for the degradation of naturally weathered polyethylene films

    OpenAIRE

    Syranidou, Evdokia; Karkanorachaki, Katerina; Amorotti, Filippo; Repouskou, Eftychia; Kroll, Kevin; Kolvenbach, Boris; Corvini, Philippe F-X; Fava, Fabio; Kalogerakis, Nicolas

    2017-01-01

    This study investigated the potential of bacterial-mediated polyethylene (PE) degradation in a two-phase microcosm experiment. During phase I, naturally weathered PE films were incubated for 6 months with the indigenous marine community alone as well as bioaugmented with strains able to grow in minimal medium with linear low-density polyethylene (LLDPE) as the sole carbon source. At the end of phase I the developed biofilm was harvested and re-inoculated with naturally weathered PE films. Bac...

  18. Structure and properties of porous films based on aliphatic copolyamide developed for cellular technologies

    Czech Academy of Sciences Publication Activity Database

    Dobrovol`skaya, I.P.; Popryadukhin, P.V.; Yudin, V. E.; Ivankova, E.M.; Elokhovskiy, V.Y.; Weishauptová, Zuzana; Balík, Karel

    2015-01-01

    Roč. 26, č. 1 (2015), article number 46 ISSN 0957-4530 Institutional support: RVO:67985891 Keywords : porous film * aliphatic copolyamide * structure * properties Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.272, year: 2015 http://www.stem-art.com/Library/Science/Structure%20and%20properties%20of%20porous%20films%20based%20on%20aliphatic%20copolyamide%20developed%20for%20cellular%20technologies.pdf

  19. FY 1998 result report. Study of a total system for the development of superconductor power application technology (Feasibility study of commercialization of superconductivity technology and study of the introductory effect. Future superconductivity technology development in Japan); 1998 nendo seika hokokusho. Chodendo denryoku oyo gijutsu kaihatsu total system nado no kenkyu chodendo gijutsu no jitsuyoka kanosei oyobi donyu kokanado no chosa (Nippon ni okeru chodendo gijutsu kaihatsu no kongo no hokosei)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    As a part of the New Sunshine Project, 'an R and D project on superconductor power application technology,' an examinational study was made as a mini project to clarify the developmental course for commercialization of superconductor technology. The superconductor technology is being watched with interest as a technology in the 21st century. In the application to the electric power/energy field, in particular, expected are the energy saving effect by high operation efficiency, excellent environmentality, developmental potentiality of new equipment/system by the application of ferromagnetism, etc. Accordingly, the paper analytically arranged the needs of superconductor devices in Japan and abroad and the technology seeds corresponding to the needs, and prepared the developmental subjects of superconductor technology. These developmental steps and the mutual relationship were expressed in an R and D framework. At the same time, as to the superconductivity, a survey outlined the projects carried out in each government office in Japan. The future developmental course was indicated, and proposals were made on the equipment/system as object which are the subjects for urgent development for commercialization. (NEDO)

  20. FY 1998 result report. Study of a total system for the development of superconductor power application technology (Feasibility study of commercialization of superconductivity technology and study of the introductory effect. Future superconductivity technology development in Japan); 1998 nendo seika hokokusho. Chodendo denryoku oyo gijutsu kaihatsu total system nado no kenkyu chodendo gijutsu no jitsuyoka kanosei oyobi donyu kokanado no chosa (Nippon ni okeru chodendo gijutsu kaihatsu no kongo no hokosei)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    As a part of the New Sunshine Project, 'an R and D project on superconductor power application technology,' an examinational study was made as a mini project to clarify the developmental course for commercialization of superconductor technology. The superconductor technology is being watched with interest as a technology in the 21st century. In the application to the electric power/energy field, in particular, expected are the energy saving effect by high operation efficiency, excellent environmentality, developmental potentiality of new equipment/system by the application of ferromagnetism, etc. Accordingly, the paper analytically arranged the needs of superconductor devices in Japan and abroad and the technology seeds corresponding to the needs, and prepared the developmental subjects of superconductor technology. These developmental steps and the mutual relationship were expressed in an R and D framework. At the same time, as to the superconductivity, a survey outlined the projects carried out in each government office in Japan. The future developmental course was indicated, and proposals were made on the equipment/system as object which are the subjects for urgent development for commercialization. (NEDO)

  1. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  2. Prospects for utilization of superconductors in the power industry

    International Nuclear Information System (INIS)

    Chernolepkov, N.A.

    1993-01-01

    Utilization of superconducting technology is greatly influenced by the discovery of the so-called high-temperature superconductors (HTS). The present report considers to what extent there is a need for HTS in up-to-date engineering and how much they are prepared for practical applications. The work on the practical use of superconductors was started about 30 years ago. As a results, two fields of the high-current superconductivity have emerged. The first category is the field in which other alternatives were inconceivable from techno-economic points of view (magnets of thermo-nuclear installations, MHD generators, inductive energy storage systems, etc.). The second category involves areas where superconductors must demonstrate the ability to compete with existing technologies (electrical devices, magnetic separators, etc.). The present overview discusses developments of various low temperature superconducting devices, estimate their potential and evaluates future applications of HTS based on the experience accumulated in the USSR and other countries. (author)

  3. Workshop on Accelerator Magnet Superconductors, Design and Optimization

    CERN Document Server

    WAMSDO Workshop

    2009-01-01

    This report contains the proceedings of the CARE-HHH-AMT Workshop on Accelerator Magnet Superconductors, Design and Optimization (WAMSDO) held at CERN from 19 to 23 May 2008. The needs in terms of superconducting magnets for the accelerator projects were discussed, mainly for the LHC interaction regions and injector upgrades, and for the GSI FAIR complex. The first part of the workshop focused on the development of superconductor and cables, i.e., low-loss Nb-Ti cables, Nb$_{3}$Sn and high-temperature superconductors. An industry session summarized the actual plans and status of the activities in the main European industries. Then, a worldwide status of the high field magnets programme was presented. A special session was devoted to fast cycled magnets, including FAIR facilities and LHC injector upgrades. A final session focused on the optimization methods and numerical tools for magnet design.

  4. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  5. Interaction between fractional Josephson vortices in multi-gap superconductor tunnel junctions

    Science.gov (United States)

    Kim, Ju H.

    In a long Josephson junction (LJJ) with two-band superconductors, fractionalization of Josephson vortices (fluxons) can occur in the broken time reversal symmetry state when spatial phase textures (i-solitons) are excited. Excitation of i-solitons in each superconductor layer of the junction, arising due to the presence of two condensates and the interband Josephson effect, leads to spatial variation of the critical current density between the superconductor layers. Similar to the situation in a YBa2 Cu3O7 - x superconductor film grain boundary, this spatial dependence of the crtitical current density can self-generate magnetic flux in the insulator layer, resulting in fractional fluxons with large and small fraction of flux quantum. Similar to fluxons in one-band superconductor LJJ, these fractional fluxons are found to interact with each other. The interaction between large and small fractional fluxons determines the size of a fluxon which includes two (one large and one small) fractional fluxons. We discuss the nature of interaction between fractional fluxons and suggest that i-soliton excitations in multi-gap superconductor LJJs may be probed by using magnetic flux measurements.

  6. Compact terahertz passive spectrometer with wideband superconductor-insulator-superconductor mixer.

    Science.gov (United States)

    Kikuchi, K; Kohjiro, S; Yamada, T; Shimizu, N; Wakatsuki, A

    2012-02-01

    We developed a compact terahertz (THz) spectrometer with a superconductor-insulator-superconductor (SIS) mixer, aiming to realize a portable and highly sensitive spectrometer to detect dangerous gases at disaster sites. The receiver cryostat which incorporates the SIS mixer and a small cryocooler except for a helium compressor has a weight of 27 kg and dimensions of 200 mm × 270 mm × 690 mm. In spite of the small cooling capacity of the cryocooler, the SIS mixer is successfully cooled lower than 4 K, and the temperature variation is suppressed for the sensitive measurement. By adopting a frequency sweeping system using photonic local oscillator, we demonstrated a spectroscopic measurement of CH(3)CN gas in 0.2-0.5 THz range.

  7. Development and Characterization of Edible Films Based on Fruit and Vegetable Residues.

    Science.gov (United States)

    Andrade, Roberta M S; Ferreira, Mariana S L; Gonçalves, Édira C B A

    2016-02-01

    Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films. © 2016 Institute of Food Technologists®

  8. Muon spin relaxation studies of heavy fermion superconductors

    International Nuclear Information System (INIS)

    Heffner, R.H.

    1993-01-01

    This talk will focus recent developments in our understanding of heavy fermion (HF) superconductors and the role that positive muon spin relaxation (μSR) studies have played in helping to elucidate their properties. As illustrations two systems will be discussed: (1) UPd 2 Al 3 , one of the most recently discovered HF superconductors, which also displays coexisting magnetic order and (2) UBe 3 doped with small quantities Of Th substituted for U, which displays an interplay between its superconducting and magnetic ground states, leading to multiple superconducting states

  9. Superconducting proximity effect in mesoscopic superconductor/normal-metal junctions

    CERN Document Server

    Takayanagi, H; Toyoda, E

    1999-01-01

    The superconducting proximity effect is discussed in mesoscopic superconductor/normal-metal junctions. The newly-developed theory shows long-range phase-coherent effect which explaines early experimental results of giant magnetoresistance oscillations in an Andreev interferometer. The theory also shows that the proximity correction to the conductance (PCC) has a reentrant behavior as a function of energy. The reentrant behavior is systematically studied in a gated superconductor-semiconductor junction. A negative PCC is observed in the case of a weak coupling between the normal metal and the external reservoir. Phase coherent ac effect is also observed when rf is irradiated to the junction.

  10. Edge instabilities of topological superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Johannes S. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Assaad, Fakher F. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Schnyder, Andreas P. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2016-07-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground state degeneracy and a diverging density of states. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry broken phases, which lift the ground-state degeneracy. Here, we employ Monte Carlo simulations combined with mean-field considerations to examine the instabilities of the flat-band edge states of d{sub xy}-wave superconductors. We find that attractive interactions induce a complex s-wave pairing instability together with a density wave instability. Repulsive interactions, on the other hand, lead to ferromagnetism mixed with spin-triplet pairing at the edge. We discuss the implications of our findings for experiments on cuprate high-temperature superconductors.

  11. Superconductor stability, 1983: a review

    International Nuclear Information System (INIS)

    Dresner, L.

    1983-01-01

    Three main topics have been discussed in this paper, namely, internally cooled superconductors, cooling by superfluid helium, and metastable magnets. The discussion of each has centered around a dominant idea, and it is fitting to highlight these ideas by way of conclusion. With regard to internally cooled superconductors, most of what we have learned in the last few years centers on the strong motion caused by the thermal expansion of helium. How naive were our early calculations that treated the helium as though it were incompressible. Our discussion of He-II was organized around the Gorter-Mellink relation and the solutions of the nonlinear diffusion equation it gives rise to. And our discussion of metastable magnets revolved around the fruitful concept of the MPZ. These three ideas are sturdy trunks that support much of the thought about superconductor stability that has flowered in the past several years

  12. High temperature resistive phase transition in A15 high temperature superconductors

    International Nuclear Information System (INIS)

    Chu, C.W.; Huang, C.Y.; Schmidt, P.H.; Sugawara, K.

    1976-01-01

    Resistive measurements were made on A15 high temperature superconductors. Anomalies indicative of a phase transition were observed at 433 0 K in a single crystal Nb 3 Sn and at 485 0 K in an unbacked Nb 3 Ge sputtered thin film. Results are compared with the high temperature transmission electron diffraction studies of Nb 3 Ge films by Schmidt et al. A possible instability in the electron energy spectrum is discussed

  13. Topological surface states in nodal superconductors.

    Science.gov (United States)

    Schnyder, Andreas P; Brydon, Philip M R

    2015-06-24

    Topological superconductors have become a subject of intense research due to their potential use for technical applications in device fabrication and quantum information. Besides fully gapped superconductors, unconventional superconductors with point or line nodes in their order parameter can also exhibit nontrivial topological characteristics. This article reviews recent progress in the theoretical understanding of nodal topological superconductors, with a focus on Weyl and noncentrosymmetric superconductors and their protected surface states. Using selected examples, we review the bulk topological properties of these systems, study different types of topological surface states, and examine their unusual properties. Furthermore, we survey some candidate materials for topological superconductivity and discuss different experimental signatures of topological surface states.

  14. Modeling forces in high-temperature superconductors

    International Nuclear Information System (INIS)

    Turner, L. R.; Foster, M. W.

    1997-01-01

    We have developed a simple model that uses computed shielding currents to determine the forces acting on a high-temperature superconductor (HTS). The model has been applied to measurements of the force between HTS and permanent magnets (PM). Results show the expected hysteretic variation of force as the HTS moves first toward and then away from a permanent magnet, including the reversal of the sign of the force. Optimization of the shielding currents is carried out through a simulated annealing algorithm in a C++ program that repeatedly calls a commercial electromagnetic software code. Agreement with measured forces is encouraging

  15. Application of high temperature superconductors for fusion

    International Nuclear Information System (INIS)

    Fietz, W.H.; Heller, R.; Schlachter, S.I.; Goldacker, W.

    2011-01-01

    The use of High Temperature Superconductor (HTS) materials in future fusion machines can increase the efficiency drastically. For ITER, W7-X and JT-60SA the economic benefit of HTS current leads was recognized after a 70 kA HTS current lead demonstrator was designed, fabricated and successfully tested by Karlsruhe Institute of Technology (KIT, which is a merge of former Forschungszentrum Karlsruhe and University of Karlsruhe). For ITER, the Chinese Domestic Agency will provide the current leads as a part of the superconducting feeder system. KIT is in charge of design, construction and test of HTS current leads for W7-X and JT-60SA. For W7-X 14 current leads with a maximum current of 18.2 kA are required that are oriented with the room temperature end at the bottom. JT60-SA will need 26 current leads (20 leads - 20 kA and 6 leads - 25.7 kA) which are mounted in vertical, normal position. These current leads are based on BiSCCO HTS superconductors, demonstrating that HTS material is now state of the art for highly efficient current leads. With respect to future fusion reactors, it would be very promising to use HTS material not only in current leads but also in coils. This would allow a large increase of efficiency if the coils could be operated at temperatures ≥65 K. With such a high temperature it would be possible to omit the radiation shield of the coils, resulting in a less complex cryostat and a size reduction of the machine. In addition less refrigeration power is needed saving investment and operating costs. However, to come to an HTS fusion coil it is necessary to develop low ac loss HTS cables for currents well above 20 kA at high fields well above 10 T. The high field rules BiSCCO superconductors out at temperatures above 50 K, but RE-123 superconductors are promising. The development of a high current, high field RE-123 HTS fusion cable will not be targeted outside fusion community and has to be in the frame of a long term development programme for

  16. Oxygen diffusion in cuprate superconductors

    International Nuclear Information System (INIS)

    Routbort, J.L.; Rothman, S.J.

    1995-01-01

    Superconducting properties of the cuprate superconductors depend on the oxygen content of the material; the diffusion of oxygen is thus an important process in the fabrication and application of these materials. This article reviews studies of the diffusion of oxygen in La 2-x Sr x CuO 4 , YBa 2 Cu 3 O 7- δ, YBa 2 Cu 4 O 8 , and the Bi 2 Sr 2 Ca n-1 Cu n O 2+4 (n = 1, and 2) superconductors, and attempt to elucidate the atomic mechanisms responsible

  17. Method of fabricating composite superconductors

    International Nuclear Information System (INIS)

    Koike, Y.; Shiraki, H.; Suzuki, E.; Yoshida, M.

    1977-01-01

    A method of making stabilized superconductors of a composition such as Nb 3 Sn is disclosed. The method includes forming a stock product comprising a tin base alloy as a core with a copper jacket and having a niobium tube clad thereon. The stock product is then embedded in a good thermally and electrically conducting matrix which is then coreduced until the desired size is obtained. This cold worked product is then submitted to a heat treatment to form superconductors of Nb 3 Sn

  18. Development of wear resistant zirconium oxide thin films on stainless steel substrates

    International Nuclear Information System (INIS)

    Then, I.K.; Mujahid, M.; Zhang, B.

    2005-01-01

    The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 μm in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650 C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced. (orig.)

  19. Development of wear resistant zirconium oxide thin films on stainless steel substrates

    Energy Technology Data Exchange (ETDEWEB)

    Then, I.K.; Mujahid, M. [School of Materials Engineering, Nanyang Technological Univ. (Singapore); Zhang, B. [Dou Yee Technologies Pte Ltd, Bedok Industrial Park C (Singapore)

    2005-07-01

    The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 {mu}m in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650 C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced. (orig.)

  20. Copper Antimony Chalcogenide Thin Film PV Device Development

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Adam W.; Baranowski, Lauryn L.; de Souza Lucas, Francisco Willian; Toberer, Eric S.; Wolden, Colin A.; Zakutayev, Andriy

    2015-06-14

    Emerging ternary chalcogenide thin film solar cell technologies, such as CuSbS2 and CuSbSe2, have recently attracted attention as simpler alternatives to quaternary Cu2ZnSnS4 (CZTS). Despite suitable photovoltaic properties, the initial energy conversion efficiency of CuSbS2 is rather low (0.3%). Here, we report on our progress towards improving the efficiency of CuSbS2 solar cells using a high throughput approach. The combinatorial methodology quickly results in baseline solar cell prototypes with 0.6% efficiency, and then modification of the back contact architecture leads to 1% PV devices. We then translate the optimal CuSbS2 synthesis parameters to CuSbSe2 devices, which show 3% efficiencies.

  1. Growth, characterization and device development in monocrystalline diamond films

    Science.gov (United States)

    Davis, R. F.; Glass, J. T.; Nemanich, R. J.; Bozeman, S. P.; Sowers, A. T.

    1995-06-01

    Experimental and theoretical studies concerned with interface interactions of diamond with Si, Ni, and Ni3Si substrates have been conducted. Oriented diamond films deposited on (100) Si were characterized by polar Raman, polar x-ray diffraction (XRD), and cross-sectional high resolution transmission electron microscopy (HRTEM). These sutides showed that the diamond(100)/Si(100) interface adopted the 3:2-match arrangement rather than a 45 deg rotation. Extended Hueckel tight-binding (EHTB) electronic structure calculations for a model system revealed that the interface interaction favors the 3:2-match arrangement. Growth on polycrystalline Ni3Si resulted in oriented diamond particles; under the same growth conditions, graphite was formed on the nickel substrate. Our EHTB electronic structure calculations showed that the (111) and (100) surfaces of Ni3Si have a strong preference for diamond nucleation over graphite nucleation, but this was not the case for the (111) and (100) surfaces of Ni.

  2. High critical currents in heavily doped (Gd,Y)Ba2Cu3Ox superconductor tapes

    International Nuclear Information System (INIS)

    Selvamanickam, V.; Gharahcheshmeh, M. Heydari; Xu, A.; Galstyan, E.; Delgado, L.; Cantoni, C.

    2015-01-01

    REBa 2 Cu 3 O x ((REBCO), RE = rare earth) superconductor tapes with moderate levels of dopants have been optimized for high critical current density in low magnetic fields at 77 K, but they do not exhibit exemplary performance in conditions of interest for practical applications, i.e., temperatures less than 50 K and fields of 2–30 T. Heavy doping of REBCO tapes has been avoided by researchers thus far due to deterioration in properties. Here, we report achievement of critical current densities (J c ) above 20 MA/cm 2 at 30 K, 3 T in heavily doped (25 mol. % Zr-added) (Gd,Y)Ba 2 Cu 3 O x superconductor tapes, which is more than three times higher than the J c typically obtained in moderately doped tapes. Pinning force levels above 1000 GN/m 3 have also been attained at 20 K. A composition map of lift factor in J c (ratio of J c at 30 K, 3 T to the J c at 77 K, 0 T) has been developed which reveals the optimum film composition to obtain lift factors above six, which is thrice the typical value. A highly c-axis aligned BaZrO 3 (BZO) nanocolumn defect density of nearly 7 × 10 11  cm −2 as well as 2–3 nm sized particles rich in Cu and Zr have been found in the high J c films

  3. Superconductor-insulator transitions in 2D: the experimental situation

    International Nuclear Information System (INIS)

    Markovic, N.; Christiansen, C.; Mack, A.; Goldman, A.M.

    2000-01-01

    Superconductor-insulator (SI) transitions in ultrathin films have attracted significant attention over the last decade because of the possibility that they are quantum phase transitions. Magnetic field, film thickness, or carrier concentration can be used as control parameters. The bosonic pictures of these transitions proposed some years ago are only in qualitative agreement with experiment. In particular, the critical resistance appears not to be universal, and there are variations in the values of critical exponents. It has been concluded that in real films fermionic degrees of freedom must be taken into account. There are also indications that the phase diagram may include a significant metallic phase separating the superconducting and insulating phases, and that the transition may have a significant percolative aspect. The experimental situation will be broadly reviewed with attention paid to issues relating to materials and measurements. (orig.)

  4. Stability of superconductor

    International Nuclear Information System (INIS)

    Wada, Hitoshi; Takeuchi, Takao; Kuroda, Tsuneo

    2000-01-01

    To evaluate the stability of superconductors, we constructed a measurement system of the critical current density Jr property as function of temperature, magnetic strength, azimuth of magnetic field and distortion. LabView program automatically controlled the magnetic field, temperature, rotational displacement, load, multimeter and sample source in the system. The superconducting critical surface of Nb 3 Al wire was prepared by two methods: a low temperature diffusion method and a phase transformation method. Nb 3 Al prepared by two methods proved the temperature scaling law of magnetic pinning force density and parameters for fitting the pinning model were introduced. The tailing of Jc-T curve at the high temperature side was generated by pinning property of magnetic flux line. On measurement of AC magnetic susceptibility, a primary stack (JR filament) of RIT Nb 3 Al wire prepared by phase transformation connected electrically and the size corresponded to the effective core size, so that, large n value was shown in spite of high temperature treatment and it showed good distortion resistance. Nb 3 Al wire prepared by low temperature diffusion method indicated large anisotropy of Bc 2 and Jc in the rectangular wire. On V 3 Ga, the temperature scaling law of magnetic field was not established and it was observed the effective grain boundary pinning at the low magnetic field and the other pinning mechanism of which magnetic flux line synchronized in the high temperature field. The specific magnetic azimuth dependency showed in the neighborhood of the parallel magnetic field. Jc indicated the positive dependence of temperature in the peak magnetic field. Jc of Bi oxides tape conductor was measured and the results showed the magnetic field was governed by magnetic field dependence on the c axis direction. (S.Y.)

  5. Static Properties of Superconductor Journal Bearing Substator for Superconductor Flywheel Energy Storage System

    International Nuclear Information System (INIS)

    Park, B. J.; Jung, S. Y.; Lee, J. P.; Park, B. C.; Jeong, N. H.; Sung, T. H.; Han, Y. H.

    2008-01-01

    A Superconductor Flywheel Energy Storage System(SFES) mainly consists of a pair of non-contacting High Temperature Superconductor(HTS) bearings that provide very low frictional losses, a composite flywheel with high energy storage density. The HTS bearings, which offer dynamic stability without active control, are the key technology that distinguishes the SFES from other flywheel energy storage devices, and great effort is being put into developing this technology. The Superconductor Journal Bearing(SJB) mainly consists of HTS bulks and a stator, which holds the HTS bulks and also acts as a cold head. Static properties of HTS bearings provide data to solve problems which may occur easily in a running system. Since stiffness to counter vibration is the main parameter in designing an HTS bearing system, we investigate SJB magnetic force through static properties between the Permanent Magnet(PM) and HTS. We measure stiffness in static condition and the results are used to determine the optimal number of HTS bulks for a 100kWh SFES.

  6. High T(c) superconductors: Technical and commercial challenge

    Science.gov (United States)

    Kirschner, I.; Horvath, E.; Vajda, I.; Bencze, L.; Goebl, N.

    1995-01-01

    Some basic questions of the way which leads from the discovery of high-T(c) superconductors to their applications is surveyed. The influence of high-T(c) superconducting technology on the industrial and social development is also briefly analyzed.

  7. Plastic strain and flux jumps in hard and composite superconductors

    International Nuclear Information System (INIS)

    Maksimov, I.L.; Mints, R.G.

    1981-01-01

    A study is made into the effect of the critical current density dependence upon the value of plastic strain on the critical state stability in hard and composite superconductors under conditions of plastic yield of the material. Criteria of the critical state stability relative to the jointly developing magnetic flux jumps and plastic strain jerks, are found. (author)

  8. Iron-based superconductors via soft chemistry

    International Nuclear Information System (INIS)

    Friederichs, Gina Maya

    2015-01-01

    This thesis provides new soft chemistry approaches to Fe-based superconductors. Mild syntheses were demonstrated to be able to overcome difficulties, occurring in conventional synthesis and to enable the access to new metastable phases. A solvent-based metathesis reaction led to β-FeSe exclusively. Contrary to solid state syntheses, the formation of hexagonal α-FeSe could be avoided under mild conditions. The deintercalation of interstitial Fe (by formation of Fe 3 O 4 ) could be proven by low temperature O 2 -annealing of Fe 1+x Te 1-y Se y . By using redox (de)intercalations K 1-x Fe 2-y Se 2 , metastable Na 1-x Fe 2-y As 2 and Na 1-x ((Fe 1-y Co y ) 1-z As) 2 could successfully be obtained at room temperature. The mild synthesis conditions led to compounds like FeSe and K 1-x Fe 2-y Se 2 which exhibited different physical properties than found by conventional high temperature methods. In general, the developed (de)intercalation reactions represent a new, universally applicable tool in order to manipulate the structure along with the properties of Fe-based superconductors. The basic structural features of the characteristic FeX 4/4 tetrahedral layers, however, are preserved. Soft chemistry syntheses have been shown to allow the formation of a variety of phases, like Na 1-x Fe 2-y As 2 , Na 1-x ((Fe 1-y Co y ) 1-z As) 2 and K 1-x Fe 2-y Se 2 . Hence, especially low temperature approaches may enable the realization of complex stacking sequences, potentially leading to the fulfillment of the greatest goal in the research of superconductors - room temperature superconductivity.

  9. Magnesium Diboride thin Films, multilayers, and coatings for SRF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Xiaoxing [Temple Univ., Philadelphia, PA (United States)

    2017-08-17

    Superconducting radio frequency (SRF) cavities currently use low-temperature superconductor niobium, and the Nb SRF cavities have approached the performance levels predicted theoretically. Compared to Nb, MgB2 becomes superconducting at a much higher temperature and promises a better RF performance in terms of higher quality factor Q and higher acceleration capability. An MgB2 SRF technology can significantly reduce the operating costs of particle accelerators when these potentials are realized. This project aimed to advance the development of an MgB2 SRF technology. It had two main objectives: (1) materials issues of MgB2 thin films and multilayers related to their applications in SRF cavities; and (2) coating single-cell cavities for testing at RF frequencies. The key technical thrust of the project is the deposition of high quality clean MgB2 films and coatings by the hybrid physical-chemical vapor deposition (HPCVD) technique, which was developed in my group. We have achieved technical progress in each of the two areas. For the first objective, we have confirmed that MgB2 thin film coatings can be used to effectively enhance the vortex penetration field of an SRF cavity. A vortex is a normal region in the shape of spaghetti that threads through a superconductor. Its existence is due to an applied magnetic field that is greater than a so-called lower critical field, Hc1. Once a vortex enters the superconductor, its movement leads to loss. This has been shown to be the reason for an SRF cavity to break down. Thus, enhancing the magnetic field for a vortex to enter the superconductor that forms the SRF cavity has be a goal of intense research. To this end, Gurevich proposed that a coating of thin superconductor layer can impede the vortex entrance. In this project, we have done two important experiment to test this concept. One, we showed that the enhancement of Hc1 can be

  10. Reel Science: An Ethnographic Study of Girls' Science Identity Development in and through Film

    Science.gov (United States)

    Chaffee, Rachel L.

    2016-01-01

    This dissertation study contributes to the research on filmmaking and identity development by exploring the ways that film production provided unique opportunities for a team of four girls to engage in science, to develop identities in science, and to see and understand science differently. Using social practice, identity, and feminist theory and…

  11. Development and characterization of sugar palm starch and poly(lactic acid) bilayer films.

    Science.gov (United States)

    Sanyang, M L; Sapuan, S M; Jawaid, M; Ishak, M R; Sahari, J

    2016-08-01

    The development and characterization of environmentally friendly bilayer films from sugar palm starch (SPS) and poly(lactic acid) (PLA) were conducted in this study. The SPS-PLA bilayer films and their individual components were characterized for their physical, mechanical, thermal and water barrier properties. Addition of 50% PLA layer onto 50% SPS layer (SPS50-PLA50) increased the tensile strength of neat SPS film from 7.74 to 13.65MPa but reduced their elongation at break from 46.66 to 15.53%. The incorporation of PLA layer significantly reduced the water vapor permeability as well as the water uptake and solubility of bilayer films which was attributed to the hydrophobic characteristic of the PLA layer. Furthermore, scanning electron microscopy (SEM) image of SPS50-PLA50 revealed lack of strong interfacial adhesion between the SPS and PLA. Overall, the incorporation of PLA layer onto SPS films enhances the suitability of SPS based films for food packaging. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Response of custom-developed radiochromic dye films after electron irradiation

    International Nuclear Information System (INIS)

    Vargas-Aburto, C.; Uribe, R.M.; McLauglin, W.L.; Dick, C.E.

    1995-01-01

    Radiochromic dye (RD) films with varying formulations have been produced in this laboratory and are being used to aid in the determination of both the absorbed dose in irradiated test materials as well as the spatial homogeneity of the electron beam used to perform the irradiations. Specifically, these films have been used during the irradiation of both photovoltaic (solar cells) and liquid crystal-based devices (light valves). However, the optical response of RD films is known to be affected by post-irradiation conditions, such as the storage time and temperature, among others. This work represents a study of the time-dependence of the response of the custom-developed RD films. The change in response has been studied for every formulation, as a function of two different post-irradiation storage temperatures (23 degrees C and 45 degrees C) for a period of six months. Results show that significant changes in the response of these films can be observed even after this extended period. These results are compared with those obtained by other authors on similar films subjected to both electron and gamma ( 60 Co) radiation

  13. Development of tantalum oxynitride thin films produced by PVD: Study of structural stability

    Energy Technology Data Exchange (ETDEWEB)

    Cristea, D. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Department of Materials Science, Transylvania University, 500036 Brasov (Romania); Crisan, A. [Department of Materials Science, Transylvania University, 500036 Brasov (Romania); Barradas, N.P.; Alves, E. [Instituto Superior Técnico, Universidade Técnica de Lisboa Estrada Nacional 10, ao km 139,7 2695-066, Bobadela LRS (Portugal); Moura, C.; Vaz, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Cunha, L., E-mail: lcunha@fisica.uminho.pt [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2013-11-15

    The purpose of this work is to study the evolution of the structure and of the thermal stability of a group of tantalum oxynitride thin films, prepared by magnetron sputtering, under the influence of vacuum annealing, up to a temperature of 800 °C. When varying the partial pressure of the reactive gases (P{sub O{sub 2+N{sub 2}}}), during the deposition process, the films change from a structure with a combination of poorly developed crystallites of the tetragonal β-Ta and of the face centred cubic (fcc) Ta(O,N) phases, for the films deposited with low P{sub O2+N2}, to a quasi-amorphous structure, for the films deposited with highest pressures. For intermediate pressures, the films reveal the presence of the fcc-Ta(O,N) structure. This structure corresponds to O atoms substituting some of the N atoms on the fcc-TaN structure and/or N atoms substituting O atoms of the fcc-γ-TaO structure. When subjected to the thermal annealing at 700 °C or higher, the film produced with lowest partial pressure revealed a remarkable structural change. New diffraction peaks appear and can only be attributed to a sub-stoichiometric hexagonal tantalum nitride structure. The film did not reveal any signs of delamination or cracks after all annealing temperatures. The two films produced with highest partial pressure proved to be the most stable. Structurally, they maintain the amorphous structure after all the annealing treatments and, in addition, no cracks or delamination were detected.

  14. Development of orodispersible polymer films with focus on the solid state characterization of crystalline loperamide.

    Science.gov (United States)

    Woertz, Christina; Kleinebudde, Peter

    2015-08-01

    The formulation of active pharmaceutical ingredients (API) as orodispersible films is gaining interest among novel oral drug delivery systems due to their small size, enhanced flexibility and improved patient compliance. The aim of this work was the preparation and characterization of orodispersible films containing loperamide hydrochloride (LPH) as model drug. As loperamide hydrochloride is poorly soluble in water it was used in crystalline form with a loading of 2mg/6cm(2) film. Hydroxypropyl methylcellulose (HPMC) and different types of hydroxypropyl cellulose (HPC) in different concentrations were used as film forming polymers whereas arabic gum, xanthan gum and tragacanth served as thickening agents. Films were characterized with respect to the content uniformity, morphology, thermal behavior and crystallinity. Suspensions were investigated regarding their viscosity using a rotational rheometer and the crystal structure of the Active Pharmaceutical Ingredient (API) was analyzed using polarized light microscopy. The development of flexible, non-brittle and homogeneous films of LPH was feasible. Two polymorphic forms of LPH appeared in the film formulations dependent on the utilized polymer. While in presence of HPMC the original polymorphic form I remained stable in suspension and films, the polymorphic form II occurred in presence of HPC. Both polymorphic forms were prepared separately and a solid state characterization was performed. Polymorph I showed isometric crystals whereas polymorph II showed needle shaped crystals. Tragacanth was able to prevent the transformation to polymorph II, if it was dissolved first before HPC. When HPC was added first to the suspension, the conversion to form II occurred irreversibly also after further addition of tragacanth. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Development of Functional Thin Polymer Films Using a Layer-by-Layer Deposition Technique.

    Science.gov (United States)

    Yoshida, Kentaro

    2017-01-01

    Functional thin films containing insulin were prepared using layer-by-layer (LbL) deposition of insulin and negatively- or positively-charged polymers on the surface of solid substrates. LbL films composed of insulin and negatively-charged polymers such as poly(acrylic acid) (PAA), poly(vinylsulfate) (PVS), and dextran sulfate (DS) were prepared through electrostatic affinity between the materials. The insulin/PAA, insulin/PVS, and insulin/DS films were stable in acidic solutions, whereas they decomposed under physiological conditions as a result of a change in the net electric charge of insulin from positive to negative. Interestingly, the insulin-containing LbL films were stable even in the presence of a digestive-enzyme (pepcin) at pH 1.4 (stomach pH). In contrast, LbL films consisting of insulin and positively-charged polymers such as poly(allylamine hydrochloride) (PAH) decomposed in acidic solutions due to the positive charges of insulin generated in acidic media. The insulin-containing LbL films can be prepared not only on the surface of flat substrates, such as quartz slides, but also on the surface of microparticles, such as poly(lactic acid) (PLA) microbeads. Thus, insulin-containing LbL film-coated PLA microbeads can be handled as a powder. In addition, insulin-containing microcapsules were prepared by coating LbL films on the surface of insulin-doped calcium carbonate (CaCO 3 ) microparticles, followed by dissolution of the CaCO 3 core. The release of insulin from the microcapsules was accelerated at pH 7.4, whereas it was suppressed in acidic solutions. These results suggest the potential use of insulin-containing microcapsules in the development of oral formulations of insulin.

  16. Fabrication and transport studies of graphene-superconductor heterostructures

    Science.gov (United States)

    Hu, Jiuning; Wu, Tailung; Tian, Jifa; Chen, Yong

    2014-03-01

    Recently, graphene based stacked heterostructures, e.g., graphene and boron nitride (BN) multi-layers, have attracted much attention as a system to study novel interaction-driven physics (e.g., excitonic condensation) and perform interesting measurements (eg. Coulomb drag and tunneling). The realm of graphene-superconductor heterostructures remains less unexplored, while such a system offers various interesting prospects (effects of superconductor vortices lattices on over-layering graphene and quantum Hall states, where novel phenomena such as anionic excitations have been predicted). We have used polyvinyl alcohol (PVA) based carrier films and a micro-manipulator to transfer mechanically exfoliated flakes and fabricated graphene/BN/NbSe2 structures to study the transport properties of graphene in close proximity to electrically isolated superconducting NbSe2 films. The NbSe2 film shows the superconducting transition temperature of ~7 K and upper critical field of ~3.5 T after device fabrication. We will present results from magneto-transport in graphene and graphene-NbSe2 Coulomb drag and tunneling measurements.

  17. Slim-look superconductors lead the applications race

    International Nuclear Information System (INIS)

    Hellemans, A.

    1996-01-01

    When George Bednorz and Alex Mueller discovered high-temperature superconductivity (HTS) 10 years ago at IBM research labs near Zurich, newspapers, magazines, and TV news reports across the world were soon filled with forecasts of super-efficient power lines, trains floating along at unimaginable speeds levitated by superconducting magnets, and swift, silent ships powered by magnetohydro-dynamic drives. Chunks of these new ceramic materials, which can conduct electricity free form all resistance at temperatures high enough to require only cheap liquid nitrogen as a coolant rather than expensive liquid helium, would pave the way to the technological future. However, researchers are now thinking of thin films rather than chunks of HTS material. Superconductors do not always require long wires and coils or high currents. Electronic devices make from HTS ceramics have some remarkable properties, and all you need is a thin layer of film of the ceramic grown on a rigid substrate. This article discusses the possibilities of applications using new thin film superconductors

  18. Superconductor with improved persistence characteristics

    International Nuclear Information System (INIS)

    Stekly, Z. J. J.; Strauss, B. P.

    1984-01-01

    In a multifilamentary superconductor, plural filaments are separated from one another by a ductile nonsuperconducting copper matrix. The niobium titanium filaments are arrayed through the copper, with one filament being substantially larger than the others, and preferably, centrally located in the wire. Preferably also, the other filaments are arrayed in an annular configuration about the periphery of the wire

  19. Testing Superconductor Logic Integrated Circuits

    NARCIS (Netherlands)

    Arun, A.J.; Kerkhoff, Hans G.

    2005-01-01

    Superconductor logic has the potential of extremely low-power consumption and ultra-fast digital signal processing. Unfortunately, the obtained yield of the present processes is low and specific faults occur. This paper deals with fault-modelling, Design-for-Test structures, and ATPG for these

  20. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  1. Vortex lattices in layered superconductors

    International Nuclear Information System (INIS)

    Prokic, V.; Davidovic, D.; Dobrosavljevic-Grujic, L.

    1995-01-01

    We study vortex lattices in a superconductor--normal-metal superlattice in a parallel magnetic field. Distorted lattices, resulting from the shear deformations along the layers, are found to be unstable. Under field variation, nonequilibrium configurations undergo an infinite sequence of continuous transitions, typical for soft lattices. The equilibrium vortex arrangement is always a lattice of isocell triangles, without shear

  2. Superconductors by powder metallurgy techniques

    International Nuclear Information System (INIS)

    Pickus, M.R.; Wang, J.L.F.

    1976-05-01

    Fabrication methods for Nb 3 Sn type compounds are described. Information is included on the Bell Telephone process, the General Electric tape process, superconductor stability, the bronze process, powder metallurgy multifilamentary tapes and wires, and current assessment of powder metallurgy superconducting wire

  3. Dynamics of vortices in superconductors

    International Nuclear Information System (INIS)

    Weinan, E.

    1992-01-01

    We study the dynamics of vortices in type-II superconductors from the point of view of time-dependent Ginzburg-Landau equations. We outline a proof of existence, uniqueness and regularity of strong solutions for these equations. We then derive reduced systems of ODEs governing the motion of the vortices in the asymptotic limit of large Ginzburg-Landau parameter

  4. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  5. Development of elastin-like recombinamer films with antimicrobial activity

    DEFF Research Database (Denmark)

    Costa, André; Machado, Raul; Ribeiro, Artur

    2015-01-01

    In the present work we explored the ABP-CM4 peptide properties from Bombyx mori for the creation of biopolymers with broad antimicrobial activity. An antimicrobial recombinant protein-based polymer (rPBP) was designed by cloning the DNA sequence coding for ABP-CM4 in frame with the N......-terminus of the elastin-like recombinamer consisting of 200 repetitions of the pentamer VPAVG, here named A200. The new rPBP, named CM4-A200, was purified via a simplified nonchromatographic method, making use of the thermoresponsive behavior of the A200 polymer. ABP-CM4 peptide was also purified through...... the incorporation of a formic acid cleavage site between the peptide and the A200 sequence. In soluble state the antimicrobial activity of both CM4-A200 polymer and ABP-CM4 peptide was poorly effective. However, when the CM4-A200 polymer was processed into free-standing films high antimicrobial activity against...

  6. Development of a Vsible-Light-Active Film for Direct Solar Energy Storage

    Science.gov (United States)

    Salazar, Audrey

    We conceived of a two-compartment photocatalytic assembly for direct storage of solar energy as chemical potential. Our approach was to maintain reductant and oxidant in separate compartments and develop a visible light (wavelength >400nm) photo-active film to effect an uphill photoreaction between compartments. A proton exchange membrane was included in the assembly to complete the electrical circuit. Towards obtaining a working prototype of the assembly, we developed a freeze-drying method to adhere visible-light photoactive nanoparticles to a self- standing, non-porous and conductive indium tin oxide-polyvinylidene difluoride (ITO-PVDF) support film, developed in-house. We explored the possibility of employing an iron-rich metal oxide as the photocatalytic component of the film and several were explored utilizing the sodium tartrate-assisted photoreduction of Cr(VI) to Cr(III). Although the Fe2O3-coated TiO2 nanoparticles were active for photoreduction, the initial reaction rate was modest and was slowed by substantial deactivation, making it unsuitable as a photo-active material for the composite film. A complete, two-compartment assembly was prepared using cadmium sulfide (CdS) and preliminarily examined for the Cr(VI) probe reaction, however, no catalytic activity was observed. To identify the reason(s) for this observation, further testing of the apparatus and the composite film is required.

  7. Accelerated stress testing of thin film solar cells: Development of test methods and preliminary results

    Science.gov (United States)

    Lathrop, J. W.

    1985-01-01

    If thin film cells are to be considered a viable option for terrestrial power generation their reliability attributes will need to be explored and confidence in their stability obtained through accelerated testing. Development of a thin film accelerated test program will be more difficult than was the case for crystalline cells because of the monolithic construction nature of the cells. Specially constructed test samples will need to be fabricated, requiring committment to the concept of accelerated testing by the manufacturers. A new test schedule appropriate to thin film cells will need to be developed which will be different from that used in connection with crystalline cells. Preliminary work has been started to seek thin film schedule variations to two of the simplest tests: unbiased temperature and unbiased temperature humidity. Still to be examined are tests which involve the passage of current during temperature and/or humidity stress, either by biasing in the forward (or reverse) directions or by the application of light during stress. Investigation of these current (voltage) accelerated tests will involve development of methods of reliably contacting the thin conductive films during stress.

  8. Simulation of ion-beam induced defects in cuprate superconductors

    International Nuclear Information System (INIS)

    Dineva, M.; Marksteiner, M.; Lang, W.

    2005-01-01

    Full text: Heavy-ion irradiation of cuprate superconductors is well known to produce columnar defect tracks along which magnetic vortices can be pinned. Hence, this effect has a large potential for practical applications and can enhance the critical current of the high-temperature superconducting materials. On the other hand, little work has been devoted to light-ion irradiation of the new superconductors. Our previous experimental results have indicated a systematic change of electric transport properties when irradiating YBa 2 Cu 3 O 7 (YBCO) with 75 KEXV He + ions. The purpose of the present study is the investigation of the ion-target interactions with computer simulation programs based on the binary collision approximation. The program package SRIM (Stopping and Range of Ions in Matter) is widely used to simulate the impact of energetic ions (10 eV to 2 GeV) on a solid target using a quantum mechanical treatment of ion-atom collisions under the assumption of an unstructured target material. A similar program, MARLOWE, includes the exact crystalline structure of the target and, thus, is able to calculate ion channeling effects and angle dependences. Detailed results of the penetration range of ions into YBCO, scattering cascades, creation of vacancies and interstitials, are reported for various kinds of ions. One of the central results is that light ions with energy of about 80 KEXV can penetrate through thin films of the cuprate superconductors and create point defects, mainly by oxygen displacement. (author)

  9. Transparent thin-film transistor exploratory development via sequential layer deposition and thermal annealing

    International Nuclear Information System (INIS)

    Hong, David; Chiang, Hai Q.; Presley, Rick E.; Dehuff, Nicole L.; Bender, Jeffrey P.; Park, Cheol-Hee; Wager, John F.; Keszler, Douglas A.

    2006-01-01

    A novel deposition methodology is employed for exploratory development of a class of high-performance transparent thin-film transistor (TTFT) channel materials involving oxides composed of heavy-metal cations with (n - 1)d 10 ns 0 (n ≥ 4) electronic configurations. The method involves sequential radio-frequency sputter deposition of thin, single cation oxide layers and subsequent post-deposition annealing in order to obtain a multi-component oxide thin film. The viability of this rapid materials development methodology is demonstrated through the realization of high-performance TTFTs with channel layers composed of zinc oxide/tin oxide, and tin oxide/indium oxide

  10. RF properties of high-T/sub c/ superconductors

    International Nuclear Information System (INIS)

    Bohn, C.L.; Delayen, J.R.; Dos Santos, D.I.; Lanagan, M.T.; Shepard, K.W.

    1988-01-01

    We have investigated the rf properties of high-T/sub c/ superconductors over a wide range of temperature, frequency, and rf field amplitude. We have tested both bulk polycrystalline samples and thick films on silver substrates. At 150 MHz and 4.2 K, we have measured a surface resistance of 18 μ/sup /OMEGA// at low rf field and 3.6 m/sup /OMEGA// at an rf field of 270 gauss. All samples showed a strong dependence of the surface resistance on rf field; however, no breakdown of the superconducting state has been observed up to the highest field achieved (320 gauss). 9 refs., 4 figs., 1 tab

  11. Phase Equilibria Relationships of High-Tc Superconductors

    International Nuclear Information System (INIS)

    Wong-Ng, Winnie

    2011-01-01

    As an integral part of a R and D program partially supported by the Electricity Delivery and Energy Reliability Office of DOE, we have determined phase equilibria data and phase diagrams for the three generations of superconductor materials: 1st generation, (Bi,Pb)-Sr-Ca- Cu-O systems; 2nd generation, Ba-R-Cu-O systems (R=lanthanides and yttrium); and 3rd generation, MgB2 systems. Our studies involved bulk materials, single crystals and thin films. This report gives a summary of our accomplishments, a list of publications, and 15 selected journal publications.

  12. Thermally activated flux creep in A15 lattice superconductor microbridges

    International Nuclear Information System (INIS)

    Lykov, A.N.; Prishchepa, S.L.

    1984-01-01

    Current-voltage characteristics were measured for bridges of superconductors having A15 lattices at low voltages; it was found that the characteristics are then exponential, the exponential range being proportional to the resistivity of the films. The existence of thermally activated flux creep in such contacts was demonstrated by experiment. The temperature dependence of the critical bridge current was measured. It was shown that flux creep considerably affects this current. Several parameters of Abrikosov vortex motion were estimated, taking into account the interaction with pinning centers

  13. Achievement report for fiscal 1997 (New Sunshine Project) on the development of superconductor power application technology. Research on a total system / investigative research on introduction effects; 1997 nendo chodendo denryoku oyo gijutsu kaihatsu (New Sunshine keikaku) seika hokokusho. Total system nado no kenkyu / donyu koka no chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This paper describes investigation and discussion on effects of introducing a superconductor power application technology. The generator sub-committee has compared features, technical problems and development expenses in the first and second proposals, but has not reached the final conclusion. The first proposal is targeted for early realization of 200-300 MW class generators with development cost of six to seven billion yen and a development term of seven years. These developments raise largely towards practical application the levels of material technologies, fabrication and processing technologies, and analysis and design technologies. The second proposal is intended of developing 200-300 MW class generators targeted for increased diameter, as a reduced size machine of a 600-MW generator being a future generator. It will take development cost of eight to nine billion yen with the period of nine years for the development. Majority of the technologies required for developing the future 600-MW class generator can be demonstrated. The AC superconductor device sub-committee has investigated design examples, clarified the specification requirements, and investigated and studied the development measures. The oxide superconductor sub-committee has investigated and studied making wires and conductors, and device application feasibility, but has not reached the stage of presenting specific research and development methods. The practical application strategy sub-committee has also not been able to present a collective measure because of difficulty of making future prospect on the electric power business. (NEDO)

  14. Fluctuoscopy of Superconductors

    Science.gov (United States)

    Varlamov, Andrey

    2012-02-01

    The study of superconducting fluctuations (SF) is a subject of fundamental and practical importance. Since the moment of discovery SF became a noticeable part of research in the field of superconductivity (SC) and a variety of fluctuation effects have been detected. The interest to SF in SC was regenerated by the discovery of HTS, where, due to extremely short coherence length and low effective dimensionality of the electron system, SF manifest themselves in a wide range of temperatures. The characteristic feature of SF is their strong dependence on temperature and magnetic field. This allows to separate SFs from other contributions and to use them as a tool for characterization of SC systems (``fluctuoscopy'') for example to extract the values of Tc, Hc2(T) and phase-breaking time from experimental data. We present the complete results for fluctuation magneto-conductivity (FMC) and Nernst signal (FNS) of impure 2D superconductor in the whole phase diagram above the transition line Hc2(T), including the domain of quantum fluctuations. Along some line H0(T), in agreement with experimental findings, FMC becomes zero and beyond it remains small and negative. The corresponding surface in coordinates (T,H) becomes in particular non-trivial at low temperatures and close to Hc2(0), where it is trough-shaped. The observation of large FNS in HTS and conventional SC above Tc(H), has attracted much attention recently. The idea to attribute it to the entropy transport by analogy to vortices was proposed. On the other hand this giant effect, close to Tc(0), was explained in terms of SF. Our general results allow to successfully fit the available experimental data in a wide range of magnetic fields and temperatures, to extract the value of the ``ghost'' field and other parameters of SC. We offer also a qualitative consideration, which gives a natural explanation for the giant value of FNS attributing it to a strong dependence of the fluctuation Cooper pair (FCP) chemical

  15. Patterned YBa2Cu3O7-x thin films from photopolymerizable precursors

    International Nuclear Information System (INIS)

    Hung, Y.; Agostinelli, J.A.

    1990-01-01

    A technique which combines the fabrication and patterning of thin films of the high T c superconductor YBa 2 Cu 3 O 7-x has been developed. The technique possesses the essential features of the metalorganic decomposition method with the additional attribute that the metalorganic precursor is photopolymerizable. Patterns are generated directly in the precursor film using optical exposure through a mask followed by development in a solvent. A subsequent thermal treatment transforms the patterned precursor film to the oriented superconducting phase with c axis perpendicular to the substrate surface. Resistivity measurements for such a patterned film on a single crystal (100)MgO substrate show an onset to the superconducting state occurring at 85 K with zero resistivity below 67 K

  16. Sensory evaluation of aromatic foods packed in developed starch based films using fuzzy logic

    Directory of Open Access Journals (Sweden)

    Tanima Chowdhury

    2015-04-01

    Full Text Available The last two decades have seen attempts to replace non biodegradable, synthetic food packaging films with alternatives made from biopolymers. The objective of the present work was to evaluate sensory quality of tea leaf and culinary tastemaker powder when sealed in pouches based on starch films.Films were developed from corn starch and a functional polysaccharide (FP from amylose (AM, methylcellulose (MC, and hydroxypropylmethylcellulose (HPMC, using a casting technique. Pouches were stored inside a secondary package (plastic jar under ambient condition for 90 days. Sensory attributes of the stored food samples were evaluated (tea in liquor form and the scores analysed by fuzzy logic. Results were compared with similarly stored foods but using market available poly-pouches as packaging material.For tea and tastemaker in general, the relative importance of the sensory attributes under consideration was assessed as:  aroma (Highly important >taste (Highly important>colour (Highly important > strength (Important for tea, and taste (Highly important>aroma (Highly important>colour (Important>appearance (Important for tastemaker. Among the three films that were developed, the highly important sensory attributes of aroma and taste were maintained as ‘Very good’ when the foods were packed in starch–HPMC/AM film. When the products were packed in market-available poly-pouches they exhibited similar attributes. With the exception of ‘Very good’ maintenance of the colour of tastemaker by the commercial pouch, irrespective of film and food, the colour and strength/appearance were retained in the ‘Good’-‘Satisfactory’ range. The overall sensory score of tea was also maintained as ‘Very good’ in starch-HPMC film.

  17. Design and development of an in-line sputtering system and process development of thin film multilayer neutron supermirrors

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, A.; Sampathkumar, R.; Kumar, Ajaya; Bhattacharyya, D.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lagoo, K. D.; Veerapur, R. D.; Padmanabhan, M.; Puri, R. K. [Division of Remote Handling and Robotics, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhattacharya, Debarati; Singh, Surendra; Basu, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-12-15

    Neutron supermirrors and supermirror polarizers are thin film multilayer based devices which are used for reflecting and polarizing neutrons in various neutron based experiments. In the present communication, the in-house development of a 9 m long in-line dc sputtering system has been described which is suitable for deposition of neutron supermirrors on large size (1500 mm × 150 mm) substrates and in large numbers. The optimisation process of deposition of Co and Ti thin film, Co/Ti periodic multilayers, and a-periodic supermirrors have also been described. The system has been used to deposit thin film multilayer supermirror polarizers which show high reflectivity up to a reasonably large critical wavevector transfer of ∼0.06 Å{sup −1} (corresponding to m = 2.5, i.e., 2.5 times critical wavevector transfer of natural Ni). The computer code for designing these supermirrors has also been developed in-house.

  18. Thermal transport in layered structure of YBa2Cu3O7-δ superconductors

    Science.gov (United States)

    Sharma, Rakhi; Indu, B. D.

    2017-12-01

    The heat transfer study in YBa2Cu3O7-δ superconductors structures is focused on the influence of the effect of scattering events in cross-plane and in-plane references. Understanding the mechanism of controlling the thermal conductivity of layered superconductors is an area of interest for nano microelectronics and thermo-electronic technological applications. The model of the thermal conduction, and phonon transport perpendicular and parallel to the layers of YBa2Cu3O7-δ are developed. It has been justified via numerical estimation and found substantial diminution in thermal conductivities in both in-plane and cross-plane directions of layered cuprate superconductors.

  19. Development of stripper films made of high strength, long life carbon nitride

    International Nuclear Information System (INIS)

    Oyaizu, Mitsuhiro; Sugai, Isamu; Yoshida, Koji; Haruyama, Yoichi.

    1994-01-01

    The heavy ion accelerators such as tandem type van de Graaff, linear accelerators, cyclotrons and so on raise the acceleration efficiency usually by producing multivalent ions by making the charge conversion of heavy ions using carbon thin films. However, when the electrons of large atomic number ions of low energy, high intensity current are stripped, the conventional carbon thin films on the market or home made were very short in their life, and have become the cause of remarkably lowering the acceleration efficiency. The concrete objectives of the development are the use of the charge conversion of unstable nuclear ions in the E arena accelerator for JHP of the future project of Institute of Nuclear Study and the manufacture of the carbon films which are used for the charge conversion of the H beam of high energy, but at the time of exchanging the films, there is the problem of the radiation exposure of large amount, therefore, the development of high reliability, long life stripper films has been strongly demanded. The experiment was carried out by controlled carbon arc discharge process using both AC and DC and the ion beam sputtering process using reactive nitrogen gas. The results are reported. (K.I.)

  20. Advanced magneto-optical Kerr effect measurements of superconductors at low temperatures

    Directory of Open Access Journals (Sweden)

    Claudia Stahl

    2017-10-01

    Full Text Available Magneto-optical Kerr-effect (MOKE measurements of superconducting films with soft-magnetic coatings are performed at low temperatures using a laser-based MOKE set-up. An elaborate measurement scheme with internal reference allows the quantitative comparison of the temperature dependent Kerr-amplitude with the magnetic field generated by supercurrents. For this purpose, an amorphous CoFeB thin film exhibiting a large Kerr-signal is deposited directly on top of the YBCO superconductor acting as field sensing layer. It is shown that the resulting magnetic hysteresis loops of the soft-magnetic film can be used to reconstruct the electric properties of the superconductor.

  1. Imaging of topological magnetic pinning in superconductor-ferrimagnet bilayer with scanning Hall microscopy

    International Nuclear Information System (INIS)

    Marchevsky, M; Higgins, M J; Bhattacharya, S; Fratello, V J

    2011-01-01

    In a superconducting film deposited on ferromagnetic substrate with perpendicular magnetic anisotropy, vortex matter is confined by the magnetic potential landscape. Using scanning Hall microscopy we visualize flux accumulation and removal in a superconductor-ferrimagnet (S/F) bilayer prepared by rf sputtering of thin niobium film on bismuth-doped rare-earth iron garnet. Penetration of the perpendicular magnetic field in the S/F bilayer follows magnetic domain boundaries and is laterally guided by the garnet magnetization component along the field direction. Upon field removal, localization of the remnant flux at the disclination points of the labyrinthine domain pattern is observed. Our experiments show evidence for strong vortex pinning due the special topology of the domain pattern. Ac magnetic imaging of the transport current distribution in the bilayer reveals complex flow paths commensurate with the magnetic domain boundaries. Topological magnetic pinning can be a useful tool for enhancement and control of critical current in thin film superconductors.

  2. Imaging of topological magnetic pinning in superconductor-ferrimagnet bilayer with scanning Hall microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marchevsky, M [Department of Physics, Syracuse University, Syracuse, NY 12344 (United States); Higgins, M J [Princeton High School, Princeton, NJ 08540 (United States); Bhattacharya, S [Tata Institute of Fundamental Research, Mumbai 400 005 (India); Fratello, V J, E-mail: mmartchevskii@lbl.gov [Integrated Photonics, Inc., Hillsborough, NJ 08844 (United States)

    2011-02-15

    In a superconducting film deposited on ferromagnetic substrate with perpendicular magnetic anisotropy, vortex matter is confined by the magnetic potential landscape. Using scanning Hall microscopy we visualize flux accumulation and removal in a superconductor-ferrimagnet (S/F) bilayer prepared by rf sputtering of thin niobium film on bismuth-doped rare-earth iron garnet. Penetration of the perpendicular magnetic field in the S/F bilayer follows magnetic domain boundaries and is laterally guided by the garnet magnetization component along the field direction. Upon field removal, localization of the remnant flux at the disclination points of the labyrinthine domain pattern is observed. Our experiments show evidence for strong vortex pinning due the special topology of the domain pattern. Ac magnetic imaging of the transport current distribution in the bilayer reveals complex flow paths commensurate with the magnetic domain boundaries. Topological magnetic pinning can be a useful tool for enhancement and control of critical current in thin film superconductors.

  3. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  4. Growth, characterization, and device development in monocrystalline diamond films

    Science.gov (United States)

    Davis, Robert F.

    1991-12-01

    The nucleation of diamond grains on an unscratched silicon wafer is enhanced by four order of magnitude relative to scratched substrates by using negative bias enhanced microwave plasma CVD in a 2 percent methane/hydrogen plasma for an initial period. In vacuo surface analysis has revealed that the actual nucleation occurs on the amorphous C coating present on the thin SiC layer which forms as the product of the initial reaction with the Si surface. It is believed that the C forms critical clusters which are favorable for diamond nucleation. Similar enhancement was observed together with the occurrence of textured diamond films in the use of bias pretreatment of cubic Beta SiC substrates. Approximately 50 percent of the initial diamond nuclei were aligned with the SiC substrate. In contrast, the use of the biasing pretreatment for one hour on polycrystalline substrates resulted in only about 7 percent coverage with diamond particles. Numerous techniques have been used to analyze the nucleation and growth phenomena, especially micro Raman and scanning tunneling microscopy. The latter technique has shown that the morphology of doped and undoped diamond nuclei are similar, as well as the fact that significant concentrations of vacancy related defects are present. In device related-studies, UV-photoemission studies have shown that TiC occurs at the Ti-diamond (100) interface after a 400 C anneal. The Schottky barrier height from this metal on p-type diamond was determined to be 1.0 eV. Indications of negative electron affinity (NEA) was observed and attributed to emission of electrons that are quasi-thermalized to the bottom of the conduction band. A disordered surface removes the NEA. The microwave performance of p-type (beta-doped) diamond MESFET's at 10 GHz has been further investigated. Elevated temperatures may be necessary to obtain sufficient free charge densities in the conducting channel but this will result in degraded device performance. Each of these

  5. Development and characterization of a three-dimensional radiochromic film stack dosimeter for megavoltage photon beam dosimetry.

    Science.gov (United States)

    McCaw, Travis J; Micka, John A; DeWerd, Larry A

    2014-05-01

    Three-dimensional (3D) dosimeters are particularly useful for verifying the commissioning of treatment planning and delivery systems, especially with the ever-increasing implementation of complex and conformal radiotherapy techniques such as volumetric modulated arc therapy. However, currently available 3D dosimeters require extensive experience to prepare and analyze, and are subject to large measurement uncertainties. This work aims to provide a more readily implementable 3D dosimeter with the development and characterization of a radiochromic film stack dosimeter for megavoltage photon beam dosimetry. A film stack dosimeter was developed using Gafchromic(®) EBT2 films. The dosimeter consists of 22 films separated by 1 mm-thick spacers. A Virtual Water™ phantom was created that maintains the radial film alignment within a maximum uncertainty of 0.3 mm. The film stack dosimeter was characterized using simulations and measurements of 6 MV fields. The absorbed-dose energy dependence and orientation dependence of the film stack dosimeter were investigated using Monte Carlo simulations. The water equivalence of the dosimeter was determined by comparing percentage-depth-dose (PDD) profiles measured with the film stack dosimeter and simulated using Monte Carlo methods. Film stack dosimeter measurements were verified with thermoluminescent dosimeter (TLD) microcube measurements. The film stack dosimeter was also used to verify the delivery of an intensity-modulated radiation therapy (IMRT) procedure. The absorbed-dose energy response of EBT2 film differs less than 1.5% between the calibration and film stack dosimeter geometries for a 6 MV spectrum. Over a series of beam angles ranging from normal incidence to parallel incidence, the overall variation in the response of the film stack dosimeter is within a range of 2.5%. Relative to the response to a normally incident beam, the film stack dosimeter exhibits a 1% under-response when the beam axis is parallel to the film

  6. Iron-Based Superconductors as Odd-Parity Superconductors

    Directory of Open Access Journals (Sweden)

    Jiangping Hu

    2013-07-01

    Full Text Available Parity is a fundamental quantum number used to classify a state of matter. Materials rarely possess ground states with odd parity. We show that the superconducting state in iron-based superconductors is classified as an odd-parity s-wave spin-singlet pairing state in a single trilayer FeAs/Se, the building block of the materials. In a low-energy effective model constructed on the Fe square bipartite lattice, the superconducting order parameter in this state is a combination of an s-wave normal pairing between two sublattices and an s-wave η pairing within the sublattices. The state has a fingerprint with a real-space sign inversion between the top and bottom As/Se layers. The results suggest that iron-based superconductors are a new quantum state of matter, and the measurement of the odd parity can help to establish high-temperature superconducting mechanisms.

  7. Development of PLA films containing oregano essential oil (Origanum vulgare L. virens) intended for use in food packaging.

    Science.gov (United States)

    Llana-Ruiz-Cabello, M; Pichardo, S; Bermúdez, J M; Baños, A; Núñez, C; Guillamón, E; Aucejo, S; Cameán, A M

    2016-08-01

    Consumers' concerns about the environment and health have led to the development of new food packaging materials avoiding petroleum-based matrices and synthetic additives. The present study has developed polylactic acid (PLA) films containing different concentrations of essential oil from Origanum vulgare L. virens (OEO). The effectiveness of this new active packaging was checked for use in ready-to-eat salads. A plasticising effect was observed when OEO was incorporated in PLA films. The rest of the mechanical and physical properties of developed films did not show much change when OEO was included in the film. An antioxidant effect was recorded only for films containing the highest percentages of the active agent (5% and 10%). In addition, films exhibited in vitro antibacterial activity against Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Enterococcus faecalis and Staphylococcus carnosus. Moreover, in ready-to-eat salads, antimicrobial activity was only observed against yeast and moulds, where 5% and 10% of OEO was the most effective.

  8. Orodispersible films in individualized pharmacotherapy : The development of a formulation for pharmacy preparations

    NARCIS (Netherlands)

    Visser, Caroline; Woerdenbag, Herman J.; Crediet, Stefan; Gerrits, Edwin; Lesschen, Marjan A.; Hinrichs, Wouter L.J.; Breitkreutz, Jörg; Frijlink, Henderik W.

    2015-01-01

    Orodispersible films (ODFs) are promising drug delivery systems for customized small scale pharmacy preparations. The aim of the present study was to develop a versatile casting solution suitable for the extemporaneous production of ODFs to which active pharmaceutical ingredients (APIs) can be

  9. Development of Doped Microcrystalline Silicon Oxide and its Application to Thin‑Film Silicon Solar Cells

    NARCIS (Netherlands)

    Lambertz, A.

    2015-01-01

    The aim of the present study is the development of doped microcrystalline silicon oxide (µc‑SiOx:H) alloys and its application in thin‑film silicon solar cells. The doped µc‑SiOx:H material was prepared from carbon dioxide (CO2), silane (SiH4), hydrogen (H2) gas mixtures using plasma enhanced

  10. Development surface modification technologies - A development of new nuclear materials by thin film deposition methods

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jong; Lee, Min Goo; Kim, Hyun Ho; Kim, Yong Il; Kwang, Hee Soo [Korea Advanced Institute of Scienec and Technology, Taejon (Korea, Republic of)

    1995-08-01

    Pitting corrosion of TiN-coted Inconel 600 in hightemperature chloride solution was studied. To improve the pitting resistance of Inconel 600 by depositing TiN thin film, TiN must have the thickness greater than a critical value at which the characteristics of the film itself appear. E{sub np}s of the TiN-coated sample were higher than those of the bare Inconel 600 at all the solution temperature implying that the TiN film improved the pitting resistance. The heavy defects on the surface of the substrate which were incompletely covered by TiN film served as the active sites for the pit nucleation. Fine polishing reduced those defects and improved the pitting resistance of the TiN-coated Inconel 600. The pit densities of the TiN-coated samples were much lower than those of the bare Inconel 600 at low chloride concentrations. However, at high chloride concentrations the TiN film failed to improve the pitting resistance of the Inconel. The TiN film deposited by ion-plating on Stellite was studied. The X-ray analysis shows that the deposited films were only in .delta.-TiN phase and the texture was changed from (111) to (200) with the increase of N{sub 2}/Ar ratio. The impurities in TiN films were carbon and oxygen. The amounts of these impurities were decreased greatly when the substrate bias, -200 V, was applied compared to no bias. 40 refs., 4 tabs., 20 figs. (author)

  11. Kinetic models for the development of density in photographic and radiographic film

    International Nuclear Information System (INIS)

    Darvell, B.W.; Prince Philip Dental Hospital, Hong Kong)

    1985-01-01

    The behaviour of radiographic and photographic films is usually described in terms of a plot of optical density against log (exposure). This form, based on a desired 'ideal' rather than any theory of the actual process, leads to difficulties of interpretation and arbitrary 'speed' determinations. Data collected have been shown to fit chemical kinetic models of differing order, depending on film and radiation type, with the rate constant providing a rational speed parameter. The order of the model seems to be associated with the number of quantum hits required for grain developability. A rational contrast index is proposed. (author)

  12. Development of a slip sensor using separable bilayer with Ecoflex-NBR film

    Science.gov (United States)

    Kim, Sung Joon; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

    2017-04-01

    Polymer film-type slip sensor is presented by using novel working principle rather than measuring micro-vibration. The sensor is comprised of bilayer with Ecoflex and NBR(acrylonitrile butadiene rubber) films divided by di-electric. When slip occur on surface, bilayer have relative displacement from each other because friction-induced vibration make a clearance between two layers. This displacement can be obtained by capacitance difference. CNT(carbon nanotube) was employed for electrode because of flexible and stretchable characteristics. Also normal and shear force can be decoupled by the working principle. To verify developed sensor, slip test apparatus was designed and experiments were conducted.

  13. NSSEFF Designing New Higher Temperature Superconductors

    Science.gov (United States)

    2017-04-13

    AFRL-AFOSR-VA-TR-2017-0083 NSSEFF - DESIGINING NEW HIGHER TEMPERATURE SUPERCONDUCTORS Meigan Aronson THE RESEARCH FOUNDATION OF STATE UNIVERSITY OF...2015 4. TITLE AND SUBTITLE NSSEFF - DESIGINING NEW HIGHER TEMPERATURE SUPERCONDUCTORS 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-10-1-0191 5c...materials, identifying the most promising candidates. 15. SUBJECT TERMS TEMPERATURE, SUPERCONDUCTOR 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  14. Applications of superconductors to electric motors

    International Nuclear Information System (INIS)

    McConnell, B.W.

    1988-01-01

    This paper reviews previous experience in applying superconductors to electric motors and examines the difficulties encountered. While motors and generators have a common basis, several significant differences exist. The application of high temperature superconductors to the major electric motor types is discussed and expected difficulties are presented. The limitations imposed by various motor designs are reflected in a statement of the desired material properties for high temperature superconductor electric motor applications

  15. Holographic complexity in gauge/string superconductors

    Directory of Open Access Journals (Sweden)

    Davood Momeni

    2016-05-01

    Full Text Available Following a methodology similar to [1], we derive a holographic complexity for two dimensional holographic superconductors (gauge/string superconductors with backreactions. Applying a perturbation method proposed by Kanno in Ref. [2], we study behaviors of the complexity for a dual quantum system near critical points. We show that when a system moves from the normal phase (T>Tc to the superconductor phase (T

  16. Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing

    Directory of Open Access Journals (Sweden)

    Oana Maria Dragostin

    2015-12-01

    Full Text Available The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6 showed the highest swelling ratio (197% and the highest biodegradation rate (63.04% in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5 which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity.

  17. A study on the correlations development for film boiling heat transfer on spheres

    International Nuclear Information System (INIS)

    Jeong, Yong Hoon; Baek, Won Pil; Chang, Soon Heung

    1998-01-01

    Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling have been performed. However, there is no available correlation adequate for severe accident analysis. In this study, film boiling heat transfer correlations have been developed, and their applicable ranges have been enlarged and their prediction accuracy has been enhanced

  18. A study on the correlations development for film boiling heat transfer on spheres

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yong Hoon; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-12-31

    Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corlium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling have been performed. However, there is no available correlation adequate for severe accident analysis. In this study, film boiling heat transfer correlations have been developed, and their applicable ranges have been enlarged and their prediction accuracy has been enhanced. 7 refs., 5 figs., 5 tabs. (Author)

  19. Development of polymer-bound fast-dissolving metformin buccal film with disintegrants.

    Science.gov (United States)

    Haque, Shaikh Ershadul; Sheela, Angappan

    2015-01-01

    Fast-dissolving drug-delivery systems are considered advantageous over the existing conventional oral dosage forms like tablets, capsules, and syrups for being patient friendly. Buccal films are one such system responsible for systemic drug delivery at the desired site of action by avoiding hepatic first-pass metabolism. Metformin hydrochloride (Met), an antidiabetic drug, has poor bioavailability due to its high solubility and low permeability. The purpose of the study reported here was to develop a polymer-bound fast-dissolving buccal film of metformin to exploit these unique properties. In the study, metformin fast-dissolving films were prepared by the solvent-casting method using chitosan, a bioadhesive polymer. Further, starch, sodium starch glycolate, and microcrystalline cellulose were the disintegrants added to different ratios, forming various formulations (F1 to F7). The buccal films were evaluated for various parameters like weight variation, thickness, folding endurance, surface pH, content uniformity, tensile strength, and percentage of elongation. The films were also subjected to in vitro dissolution study, and the disintegration time was found to be less than 30 minutes for all formulations, which was attributed to the effect of disintegrants. Formulation F6 showed 92.2% drug release within 6 minutes due to the combined effect of sodium starch glycolate and microcrystalline cellulose.

  20. Development of liquid film thickness measurement technique by high-density multipoint electrodes method

    International Nuclear Information System (INIS)

    Arai, Takahiro; Furuya, Masahiro; Kanai, Taizo

    2010-01-01

    High-density multipoint electrode method was developed to measure a liquid film thickness transient on a curved surface. The devised method allows us to measure spatial distribution of liquid film with its conductance between electrodes. The sensor was designed and fabricated as a multilayer print circuit board, where electrode pairs were distributed in reticular pattern with narrow interval. In order to measure a lot of electrode pairs at a high sampling rate, signal-processing method used by the wire mesh sensor measurement system was applied. An electrochemical impedance spectrometry concludes that the sampling rate of 1000 slices/s is feasible without signal distortion by electric double layer. The method was validated with two experimental campaigns: (1) a droplet impingement on a flat film and (2) a jet impingement on a rod-shape sensor surface. In the former experiment, a water droplet having 4 mm in diameter impinged onto the 1 mm thick film layer. A visual observation study with high-speed video camera shows after the liquid impingement, the water layer thinning process was clearly demonstrated with the sensor. For the latter experiment, the flexible circuit board was bended to form a cylindrical shape to measure water film on a simulated fuel rod in bundle geometry. A water jet having 3 mm in diameter impinged onto the rod-shape sensor surface. The process of wetting area enlargement on the rod surface was demonstrated in the same manner that the video-frames showed. (author)

  1. A study on the correlations development for film boiling heat transfer on spheres

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yong Hoon; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corlium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling have been performed. However, there is no available correlation adequate for severe accident analysis. In this study, film boiling heat transfer correlations have been developed, and their applicable ranges have been enlarged and their prediction accuracy has been enhanced. 7 refs., 5 figs., 5 tabs. (Author)

  2. Development and Characterization of Photoinduced Acrylamide-Grafted Polylactide Films for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Mijanur Rahman

    2017-01-01

    Full Text Available Surface grafting of biodegradable/biocompatible polylactide (PLA films by a UV-assisted reaction has been developed by employing a hydrophilic acrylamide (Am monomer, an N,N′-methylenebisacrylamide (MBAm cross-linker, and a camphorquinone (CQ/N,N′-dimethylaminoethylmethacrylate (DMAEMA photoinitiator/coinitiator system. The accomplishment of the process is confirmed by FTIR and XPS analyses. Physicochemical changes of the grafted PLA films are evaluated in terms of chemical structures, radiation-induced degradation followed by crystallization, morphology, thermal properties, and mechanical behavior. The results reveal that a low degree of PLA degradation through chain scission is observed in both blank and grafted PLA films. This generates more polar chain ends that can further induce crystallization. Results from contact angle measurements indicate that the grafted films have higher hydrophilicity and pH-responsive behavior. The incorporation of PAm on the film’s surface and the induced crystallization lead to improvements in certain aspects of mechanical properties of the films. The materials have high potential for use in biomedical and environmental applications, such as cell culture substrates or scaffolds or pH-sensitive absorbents.

  3. Development of polymer-bound fast-dissolving metformin buccal film with disintegrants

    Directory of Open Access Journals (Sweden)

    Haque SE

    2015-10-01

    Full Text Available Shaikh Ershadul Haque, Angappan Sheela Materials Chemistry Division, Centre for Nanomaterials, School of Advanced Sciences, VIT University, Vellore, India Abstract: Fast-dissolving drug-delivery systems are considered advantageous over the existing conventional oral dosage forms like tablets, capsules, and syrups for being patient friendly. Buccal films are one such system responsible for systemic drug delivery at the desired site of action by avoiding hepatic first-pass metabolism. Metformin hydrochloride (Met, an antidiabetic drug, has poor bioavailability due to its high solubility and low permeability. The purpose of the study reported here was to develop a polymer-bound fast-dissolving buccal film of metformin to exploit these unique properties. In the study, metformin fast-dissolving films were prepared by the solvent-casting method using chitosan, a bioadhesive polymer. Further, starch, sodium starch glycolate, and microcrystalline cellulose were the disintegrants added to different ratios, forming various formulations (F1 to F7. The buccal films were evaluated for various parameters like weight variation, thickness, folding endurance, surface pH, content uniformity, tensile strength, and percentage of elongation. The films were also subjected to in vitro dissolution study, and the disintegration time was found to be less than 30 minutes for all formulations, which was attributed to the effect of disintegrants. Formulation F6 showed 92.2% drug release within 6 minutes due to the combined effect of sodium starch glycolate and microcrystalline cellulose. Keywords: chitosan, sodium starch glycolate, microcrystalline cellulose, drug-delivery system, immediate release

  4. New application of superconductors: High sensitivity cryogenic light detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cardani, L., E-mail: laura.cardani@roma1.infn.it [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Physics Department, Princeton University, Washington Road, 08544 Princeton, NJ (United States); Bellini, F.; Casali, N. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); Castellano, M.G. [Istituto di Fotonica e Nanotecnologie – CNR, Via Cineto Romano 42, 00156 Roma (Italy); Colantoni, I.; Coppolecchia, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Cosmelli, C.; Cruciani, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); D' Addabbo, A. [INFN – Laboratori Nazionali del Gran Sasso, Assergi (L' Aquila) 67010 (Italy); Di Domizio, S. [INFN – Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Martinez, M. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); Laboratorio de Fisica Nuclear y Astroparticulas, Universidad de Zaragoza, Zaragoza 50009 (Spain); Tomei, C. [INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); and others

    2017-02-11

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs) that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2×2 cm{sup 2} substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement.

  5. Proceedings, phenomenology and applications of high temperature superconductors

    International Nuclear Information System (INIS)

    Bedell, K.S.

    1991-01-01

    Phenomenology and Applications of High Temperature Superconductors, The Los Alamos Symposium: 1991, was sponsored by the Los Alamos National Laboratory, Center for Materials Science, the Advanced Studies Program on High Temperature Superconductivity Theory (ASP) and the Exploratory Research and Development Center. This is the second symposium in the series. High Temperature Superconductivity, The Los Alamos Symposium: 1989, also published by Addison Wesley, focused on the cutting-edge theoretical and experimental issues in high temperature superconductors. This symposium, with its focus on the phenomenology and applications of high temperature superconductors, gives a complementary review of the aspects of the field closely related to the impact of high temperature superconductors on technology. The objective of ASP is to advance the field on a broad front with no specific point of view by bringing a team of leading academic theorists into a joint effort with the theoretical and experimental scientists of a major DOE national laboratory. The ASP consisted of fellows led by Robert Schrieffer (UCSB and now FSU) joined by David Pines (University of illinois), Elihu Abrahams (Rutgers), Sebastian Doniach (Stanford), and Maurice Rice (ETH, Zurich) and theoretical and experimental staff of Los Alamos National Laboratory. This synergism of academic, laboratory, theoretical and experimental research produced a level of interaction and excitement that would not be possible otherwise. This publication and the previous one in the series are just examples of how this approach to advancing science can achieve significant contributions

  6. New application of superconductors: High sensitivity cryogenic light detectors

    International Nuclear Information System (INIS)

    Cardani, L.; Bellini, F.; Casali, N.; Castellano, M.G.; Colantoni, I.; Coppolecchia, A.; Cosmelli, C.; Cruciani, A.; D'Addabbo, A.; Di Domizio, S.; Martinez, M.; Tomei, C.

    2017-01-01

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs) that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2×2 cm"2 substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement.

  7. Development and implementation of an automated quantitative film digitizer quality control program

    Science.gov (United States)

    Fetterly, Kenneth A.; Avula, Ramesh T. V.; Hangiandreou, Nicholas J.

    1999-05-01

    A semi-automated, quantitative film digitizer quality control program that is based on the computer analysis of the image data from a single digitized test film was developed. This program includes measurements of the geometric accuracy, optical density performance, signal to noise ratio, and presampled modulation transfer function. The variability of the measurements was less than plus or minus 5%. Measurements were made on a group of two clinical and two laboratory laser film digitizers during a trial period of approximately four months. Quality control limits were established based on clinical necessity, vendor specifications and digitizer performance. During the trial period, one of the digitizers failed the performance requirements and was corrected by calibration.

  8. Towards developing an efficient sensitive element for trinitrotoluene detection: TiO{sub 2} thin films functionalized with molecularly imprinted copolymer films

    Energy Technology Data Exchange (ETDEWEB)

    Lazau, Carmen [National Institute for Research and Development in Electrochemistry and Condensed Matter, Condensed Matter Department, 1 P. Andronescu Street, 300224 Timisoara (Romania); Iordache, Tanta-Verona [National Research and Development Institute for Chemistry and Petrochemistry INCDCP-ICECHIM, Advanced Polymer Materials and Polymer Recycling, 202 Splaiul Independentei, 060021 Bucharest (Romania); Florea, Ana-Mihaela [National Research and Development Institute for Chemistry and Petrochemistry INCDCP-ICECHIM, Advanced Polymer Materials and Polymer Recycling, 202 Splaiul Independentei, 060021 Bucharest (Romania); University Politehnica of Bucharest, The Faculty of Applied Chemistry and Materials Science, Bioresources and Polymer Science Department, 1-7 Polizu, 011061 Bucharest (Romania); Orha, Corina [National Institute for Research and Development in Electrochemistry and Condensed Matter, Condensed Matter Department, 1 P. Andronescu Street, 300224 Timisoara (Romania); Bandas, Cornelia, E-mail: cornelia.bandas@gmail.com [National Institute for Research and Development in Electrochemistry and Condensed Matter, Condensed Matter Department, 1 P. Andronescu Street, 300224 Timisoara (Romania); Radu, Anita-Laura; Sarbu, Andrei [National Research and Development Institute for Chemistry and Petrochemistry INCDCP-ICECHIM, Advanced Polymer Materials and Polymer Recycling, 202 Splaiul Independentei, 060021 Bucharest (Romania); Rotariu, Traian [Technical Military Academy, Chemistry Department, Bucharest (Romania)

    2016-10-30

    Highlights: • A new concept for creating reusable and more sensitive sensors for trinitrotoluene. • Titanium oxide thin films as transducers deposited by a new hydrothermal process. • Trinitrotoluene-molecularly imprinted receptors obtained by a two-step procedure. - Abstract: In this study, TiO{sub 2} films were successfully grown in-situ onto a FTO substrate by a hydrothermal method, using TiCl{sub 4} as Ti precursor, and further on functionalized with a 2,4,6-trinitrotoluene-molecularly imprinted polymer (TNT-MIP) film as a preliminary step in developing a trinitrotoluene (TNT) reusable sensor to overcome the international security issues. For investigating the TiO{sub 2} film thickness, crystalline structure and morphology, the films were autoclaved at 200 °C at different times. The X-ray diffraction showed that TiO{sub 2} films possessed a rutile structure, with no cracks visible by atomic force microscopy (AFM), and the films morphology observed by scanning electron microscopy (SEM) was highly dependent upon the hydrothermal treatment time. Yet, the TiO{sub 2} films with a more porous surface were more suitable for TNT-MIP film deposit. Rheology of precursor polymer film solutions, based on poly (acrylonitrile-co-acrylic acid), poly (acrylonitrile-co-methacrylic acid) or poly (acrylonitrile- co-itaconic acid), and the structure and adherence of TNT-MIP films were investigated in order to establish the correct recipe of the MIP. The removal yield of TNT from the imprinted films, the thickness, the porosity and the compatibility with the inorganic TiO{sub 2} film were adequate for the poly (acrylonitrile-co-acrylic acid) system with an acrylonitrile: acrylic acid practical ratio of 86.1:13.9 (wt./wt.). Farmore, AFM morphology corroborated with SEM results highlighted the effect of TNT imprinting in the copolymer matrix as the surface of the imprinted layer was quite different from that of the non-imprinted layer.

  9. Study of the inhomogeneous characteristics of modified YBa_2Cu_3O_7_-_d thin films and (YBa_2Cu_3O_7_-_d /LaAlO_3)_n superlattices: growth and properties

    International Nuclear Information System (INIS)

    Thimont, Yohann

    2009-01-01

    This manuscript is devoted to the study of crystallographic and physical properties of superconductor YBCO thin films and superconductor/insulator (YBCO/LAO)_n superlattices. The first stage of this work was to optimize the YBCO thin film deposition. Elaboration of a new physical model allows us to determine a critical temperature distribution inside the films thickness. Nevertheless, no homogeneous critical temperature inside the films can be obtained. This work shows that the interface strains modify the crystallographic and physical properties. We developed a new simulation method concerning the XRD peak shape analysis which allows us to determine YBCO cell deformation profile along the c-bar axis. About superlattices, effects of thickness on the physical and structural properties have been noticed. Transmission Electron Microscopy exhibits existence of structural defects in the films. Ending, the physical model proposed in the present work provides important information regarding the magnetic interaction between two superconductor layers, which seems to limit application of these superlattices in the realization of complex electronic devices. (author) [fr

  10. Recent status of superconductors for accelerator magnets

    International Nuclear Information System (INIS)

    Greene, A.F.

    1992-01-01

    A survey is given of superconductor wire and cable which has been or will be used for construction of dipole magnets for all of the large European and US superconducting accelerator rings. Included is a simplified view of the construction methods and operating requirements of an accelerator dipole magnet, with emphasis on required superconductor performance. The methods of fabricating Nb-Ti superconductors are described, including the critical parameters and materials requirements. The superconductor performance requirements are summarized in an effort to relate why these are important to accelerator designers. Some of the recently observed time dependent effects are covered briefly

  11. Improved magnetic-field homogeneity of NMR HTS bulk magnet using a new stacking structure and insertion of an HTS film cylinder into a bulk bore

    International Nuclear Information System (INIS)

    Itoh, Yoshitaka; Yanagi, Yousuke; Nakamura, Takashi

    2017-01-01

    A new type of superconducting bulk magnet for compact nuclear magnetic resonance (NMR) devices with high magnetic-field homogeneity has been developed by inserting an HTS film cylinder into a bulk superconductor bore. Annular 60 mmϕ Eu-Ba-Cu-O bulk superconductors with a larger inner diameter (ID) of 36 mm were sandwiched between bulk superconductors with a smaller ID of 28 mm, and the total height of the bulk superconductor set was made to be 120 mm. The inner height of central wide bore space was optimized by magnetic-field simulation so that the influence of the bulk superconductor's paramagnetic moment on applied field homogeneity was minimized during the magnetization process. An HTS film cylinder, in which Gd-Ba-Cu-O tapes were wound helically in three layers around a copper cylinder, was inserted into the bulk bore in order to compensate for the inhomogeneous field trapped by the bulk superconductor. The superconducting bulk magnet composed of the above bulk superconductor set and the film cylinder were cooled by a GM pulse tube refrigerator and magnetized at 4.747 T using the field cooling (FC) method and a conventional superconducting coil magnet adjusted to below 0.5 ppm in magnetic-field homogeneity. The NMR measurement was conducted for an H_2O sample with a diameter of 6.9 mm and a length of 10 mm by setting the sample in the center of the 20 mm ID room-temperature bore of the bulk magnet. The magnetic-field homogeneity derived from the full width at half maximum (FWHM) of the "1H spectrum of H_2O was 0.45 ppm. We confirmed that the HTS film inner cylinder was effective in maintaining the homogeneity of the magnetic field applied in the magnetization process, and as a result, a magnetic field with a homogeneity of less than 1 ppm can be generated in the bore of the bulk magnet without using shim coils. (author)

  12. Theory of quantum metal to superconductor transitions in highly conducting systems

    Energy Technology Data Exchange (ETDEWEB)

    Spivak, B.

    2010-04-06

    We derive the theory of the quantum (zero temperature) superconductor to metal transition in disordered materials when the resistance of the normal metal near criticality is small compared to the quantum of resistivity. This can occur most readily in situations in which 'Anderson's theorem' does not apply. We explicitly study the transition in superconductor-metal composites, in an swave superconducting film in the presence of a magnetic field, and in a low temperature disordered d-wave superconductor. Near the point of the transition, the distribution of the superconducting order parameter is highly inhomogeneous. To describe this situation we employ a procedure which is similar to that introduced by Mott for description of the temperature dependence of the variable range hopping conduction. As the system approaches the point of the transition from the metal to the superconductor, the conductivity of the system diverges, and the Wiedemann-Franz law is violated. In the case of d-wave (or other exotic) superconductors we predict the existence of (at least) two sequential transitions as a function of increasing disorder: a d-wave to s-wave, and then an s-wave to metal transition.

  13. Oxygen diffusion in cuprate superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Routbort, J.L.; Rothman, S.J.

    1995-01-01

    Superconducting properties of the cuprate superconductors depend on the oxygen content of the material; the diffusion of oxygen is thus an important process in the fabrication and application of these materials. This article reviews studies of the diffusion of oxygen in La{sub 2}{sub {minus}}{sub {times}}Sr{sub {times}}CuO{sub 4}, YBa{sub 2}Cu{sub 3}O{sub 7}{sub {minus}}{delta}, YBa{sub 2}Cu{sub 4}O{sub 8}, and the Bi{sub 2}Sr{sub 2}Ca{sub n}{sub {minus}}{sub 1}Cu{sub n}O{sub 2}{sub +}{sub 4} (n = 1, and 2) superconductors, and attempt to elucidate the atomic mechanisms responsible.

  14. QCD as a dual superconductor

    International Nuclear Information System (INIS)

    Zachariasen, F.

    1986-01-01

    The author describes the construction of an effective action describing long-range Yang-Mills theory. This action is motivated by a study of the system of Dyson equations and Ward identities, but cannot (yet) be derived from the underlying quantum theory. The effective action turns out to describe a medium very much like a dual relativistic superconductor; that is, with electric and magnetic fields interchanged. There is a dual Meissner effect, which serves to compress color electric fields into flux tubes, containing quantized units of color electric flux. This produces electric confinement. There is a magnetic condensate, resulting from a spontaneous symmetry breaking analogous to that in the relativistic superconductor, as in the Abelian Higgs model. He gives the motivation leading to the effective action, and describes the quantized electric flux tube solutions. Finally, he mentions briefly some other applications

  15. Theoretical studies of unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Groensleth, Martin Sigurd

    2008-07-01

    This thesis presents four research papers. In the first three papers we have derived analytical results for the transport properties in unconventional superconductors and ferromagnetic systems with multiple broken symmetries. In Paper I and parts of Paper II we have studied tunneling transport between two non-unitary ferromagnetic spin-triplet superconductors, and found a novel interplay between ferromagnetism and superconductivity manifested in the Josephson effect as a spin- and charge-current in the absence of an applied voltage across the junction. The critical amplitudes of these currents can be adjusted by the relative magnetization direction on each side of the junction. Furthermore, in Paper II, we have found a way of controlling a spin-current between two ferromagnets with spin-orbit coupling. Paper III considers a junction consisting of a ferromagnet and a non-unitary ferromagnetic superconductor, and we show that the conductance spectra contains detailed information about the superconducting gaps and pairing symmetry of the Cooper-pairs. In the last paper we present a Monte Carlo study of an effective Hamiltonian describing orbital currents in the CuO2 layers of high-temperature superconductive cuprates. The model features two intrinsically anisotropic Ising models, coupled through an anisotropic next-nearest neighbor interaction, and an Ashkin-Teller nearest neighbor fourth order coupling. We have studied the specific heat anomaly, as well as the anomaly in the staggered magnetization associated with the orbital currents and its susceptibility. We have found that in a limited parameter regime, the specific heat anomaly is substantially suppressed, while the susceptibility has a non-analytical peak across the order-disorder transition. The model is therefore a candidate for describing the breakup of hidden order when crossing the pseudo-gap line on the under-doped side in the phase diagram of high-temperature superconductors. (Author) 64 refs., figs

  16. Interaction between light and superconductors

    Science.gov (United States)

    Gilabert, Alain

    In the first part of this review article we resume briefly the fundamental aspect of the photon-superconductor interaction. The emphase is focused on the characteristic times and on the phenomenological models (the T*, the μ* models and the model of the kinetics equations) describing the out of equilibrium superconductivity. The experiments made on classical illuminated superconductors especially on tunnel junctions are then reported. In the second part we present the applied aspect of the photon-superconductor interaction. The interaction of the light with the high Tc superconductors is reviewed in the last part. Dans la première partie de cet article de revue, on résume brièvement 1'aspect fondamental de l'action des photons sur les supraconducteurs en s'attachant surtout à rappeler les différents temps caractéristiques de cette interaction et les modèles phénoménologiques (le modèle T*, le modèle μ*, le modèle des équations cinétiques) décrivant la supraconductivité hors équilibre. La seconde partie rappelle les expériences réalisées sur les supraconducteurs classiques illuminés et spécialement les jonctions tunnel ainsi que certaines applications de la supraconductivité hors équilibre comme les liens faibles controllables par des moyens optiques. La dernière partie est consacrée aux nouvelles expériences qui démarrent concernant l'action de la lumière sur les supraconducteurs à hautes températures critiques.

  17. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  18. Development of a tensile-stress-induced anisotropy in amorphous magnetic thin films

    International Nuclear Information System (INIS)

    Mandal, K.; Vazquez, M.; Garcia, D.; Castano, F.J.; Prados, C.; Hernando, A.

    2000-01-01

    Magnetic anisotropy was induced in positive magnetostrictive Fe 80 B 20 and negative magnetostrictive Co 75 Si 15 B 10 thin films by developing a tensile stress within the samples. The films were grown on the concave surfaces of mechanically bowed glass substrates. On releasing the substrates from the substrate holders, a tensile stress was developed within the samples that modified the domain structure. As a result of it, a magnetic easy axis parallel to the direction of the stress was induced in FeB sample whereas in CoSiB sample the induced easy axis was perpendicular to the direction of the developed stress. To produce magnetic multilayers with crossed anisotropy, FeB/CoSiB bilayers and FeB/Cu/CoSiB trilayers were grown on bowed substrates. The study of magnetic properties of the multilayers indicates the development of crossed anisotropy within them, particularly when the magnetic layers are separated by a nonmagnetic Cu layer

  19. Topological phase transition of Dirac superconductors in the presence of pseudo-scalar pairings

    Science.gov (United States)

    Salehi, Morteza; Jafari, S. A.

    2018-06-01

    Motivated by recent developments in the field of topological superconductors, we show that there is a topological phase transition (TPT) for three dimensional Dirac superconductors (3DDS) in the presence of pseudo-scalar superconducting order parameter which leads to the appearance of a two dimensional Majorana sea (2DMS) on its surface. The perfect Andreev-Klein transmission, resonant peak with robust character in the differential conductance and 4π periodic Josephson current are experimental signatures of 2DMS.

  20. The Origin of Tc Enhancement in Heterostructure Cuprate Superconductors

    Directory of Open Access Journals (Sweden)

    Doron L. Bergman

    2011-10-01

    Full Text Available Recent experiments on heterostructures composed of two or more films of cuprate superconductors of different oxygen doping levels have shown a remarkable Tc enhancement (up to 50% relative to single compound films. We provide a simple explanation of the enhancement which arises naturally from a collection of experimental works. We show that the enhancement could be caused by a structural change in the lattice, namely an increase in the distance of the apical oxygen from the copper-oxygen plane. This increase modifies the effective off-site interaction in the plane which in turn enhances the d-wave superconductivity order parameter. To illustrate this point we study the extended Hubbard model using the fluctuation exchange approximation.