WorldWideScience

Sample records for wire superconducting-superconducting contact

  1. Superconducting wires and methods of making thereof

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xingchen; Sumption, Michael D.; Peng, Xuan

    2018-03-13

    Disclosed herein are superconducting wires. The superconducting wires can comprise a metallic matrix and at least one continuous subelement embedded in the matrix. Each subelement can comprise a non-superconducting core, a superconducting layer coaxially disposed around the non-superconducting core, and a barrier layer coaxially disposed around the superconducting layer. The superconducting layer can comprise a plurality of Nb.sub.3Sn grains stabilized by metal oxide particulates disposed therein. The Nb.sub.3Sn grains can have an average grain size of from 5 nm to 90 nm (for example, from 15 nm to 30 nm). The superconducting wire can have a high-field critical current density (J.sub.c) of at least 5,000 A/mm.sup.2 at a temperature of 4.2 K in a magnetic field of 12 T. Also described are superconducting wire precursors that can be heat treated to prepare superconducting wires, as well as methods of making superconducting wires.

  2. Low-Cost Superconducting Wire for Wind Generators: High Performance, Low Cost Superconducting Wires and Coils for High Power Wind Generators

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    REACT Project: The University of Houston will develop a low-cost, high-current superconducting wire that could be used in high-power wind generators. Superconducting wire currently transports 600 times more electric current than a similarly sized copper wire, but is significantly more expensive. The University of Houston’s innovation is based on engineering nanoscale defects in the superconducting film. This could quadruple the current relative to today’s superconducting wires, supporting the same amount of current using 25% of the material. This would make wind generators lighter, more powerful and more efficient. The design could result in a several-fold reduction in wire costs and enable their commercial viability of high-power wind generators for use in offshore applications.

  3. Composite conductor containing superconductive wires

    Energy Technology Data Exchange (ETDEWEB)

    Larson, W.L.; Wong, J.

    1974-03-26

    A superconductor cable substitute made by coworking multiple rods of superconductive niobium--titanium or niobium--zirconium alloy with a common copper matrix to extend the copper and rods to form a final elongated product which has superconductive wires distributed in a reduced cross-section copper conductor with a complete metallurgical bond between the normal-conductive copper and the superconductor wires contained therein is described. The superconductor cable can be in the form of a tube.

  4. Sample of superconducting wiring (Niobium Titanium)

    CERN Multimedia

    About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resistan...

  5. Sample of superconducting wiring (Niobium Titanium)

    CERN Multimedia

    About NbTi cable: The cable consists of 36 strands of superconducting wire, each strand has a diameter of 0.825 mm and houses 6300 superconducting filaments of niobium-titanium (Nb-Ti, a superconducting alloy). Each filament has a diameter of about 0.006 mm, i.e. 10 times smaller than a typical human hair. The filaments are embedded in a high-purity copper matrix. Copper is a normal conducting material. The filaments are in the superconductive state when the temperature is below about -263ºC (10.15 K). When the filaments leave the superconductive state, the copper acts as conductor transports the electrical current. Each strand of The NbTi cable (at superconducting state) has a current density of up to above 2000 A/mm2 at 9 T and -271ºC (2.15 K). A cable transport a current of about 13000 A at 10 T and -271ºC (2.15 K). About LHC superconducting wiring: The high magnetic fields needed for the LHC can only be reached using superconductors. At very low temperatures, superconductors have no electrical resista...

  6. Development of Nb-Ti multifilamentar superconducting wires

    International Nuclear Information System (INIS)

    Otubo, J.

    1986-01-01

    Ni-Ti superconducting wires with multifilamentar configuration were produced, using the grouping technique. Some basic concepts on superconductivity and its main critical parameters are presented. The criteria for stabilizing superconductors in terms of the geometry are studied. The main critical parameters, H c , J c , T c in function of the composition and the metallurgical structure of Ni-Ti alloy are analysed. The development of Ni-Ti superconducting wires is described. (M.C.K.) [pt

  7. A study on the development of high-Tc superconducting wire

    International Nuclear Information System (INIS)

    Won, Dong Yeon; Chang, In Soon; Lee, Jong Min; Um, Tae Yoon; Hong, Kyae Won; Lee, Ho Jin; Lee, Hee Kwun; Kim, Chan Joong; Park, Soon Dong; Kim, Woo Gon; Kim, Ki Baek; Kwon, Sun Chil

    1992-10-01

    On this study Y-Ba-Cu-O was prepared by partial melt process and superconducting wire was fabricated by powder-in-tube method. First, mechancial properties, electrical properties, microstructure and oxygen diffusion behavior were observed. Second, through fabricated superconducting wire, conceptual design, composition and plasticity of filament superconducting wire were investigated. (Author)

  8. Superconducting wire for Lawrence Livermore National Laboratory in U.S.A

    International Nuclear Information System (INIS)

    Inoue, Itaru; Ikeda, Masaru; Tanaka, Yasuzo; Meguro, Shinichiro

    1985-01-01

    In Lawrence Livermore National Laboratory in USA, the development of a mirror type nuclear fusion reactor is carried out, and for plasma confinement, superconducting magnets are used. For the axicell coil generating a 12 T magnetic field in one of these magnets, Nb 3 Sn superconducting wires are to be used, and after the completion, it will be the largest magnet in the world as high magnetic field superconducting magnets. Furukawa Electric Co., Ltd. has completed the delivery of Nb 3 Sn superconducting wires used for this purpose. Since the Nb 3 Sn superconducting wires are very brittle, attention was paid to the manufacture to satisfy the required characteristics, and it was able to obtain the good reputation that the product was highly homogeneous as the superconducting wires of this type. In this paper, the design, manufacture and various characteristics of these superconducting wires are reported. The Nb 3 Sn superconducting wires were manufactured on industrial scale of 8 tons. The features of these Nb 3 Sn wires are the compound structure with semi-hard copper for low temperature stability and strengthening. (Kako, I.)

  9. Superconductivity optimization and phase formation kinetics study of internal-Sn Nb3Sn superconducting wires

    International Nuclear Information System (INIS)

    Zhang, Chaowu

    2007-07-01

    Superconductors Nb 3 Sn wires are one of the most applicable cryogenic superconducting materials and the best choice for high-field magnets exceeding 10 T. One of the most significant utilization is the ITER project which is regarded as the hope of future energy source. The high-Cu composite designs with smaller number of sub-element and non-reactive diffusion barrier, and the RRP (Restacked Rod Process) internal-Sn technology are usually applied for the wire manufacturing. Such designed and processed wires were supplied by MSA/Alstom and WST/NIN in this research. The systematic investigation on internal-Sn superconducting wires includes the optimization of heat treatment (HT) conditions, phase formation and its relation with superconductivity, microstructure analysis, and the phase formation kinetics. Because of the anfractuosity of the configuration design and metallurgical processing, the MF wires are not sufficient for studying a sole factor effect on superconductivity. Therefore, four sets of mono-element (ME) wires with different Sn ratios and different third-element addition were designed and fabricated in order to explore the relationship between phase formation and superconducting performances, particularly the A15 layer growth kinetics. Different characterization technic have been used (magnetization measurements, neutron diffraction and SEM/TEM/EDX analysis). The A15 layer thicknesses of various ME samples were measured and carried out linear and non-linear fits by means of two model equations. The results have clearly demonstrated that the phase formation kinetics of Nb 3 Sn solid-state reaction is in accordance with an n power relation and the n value is increased with the increase of HT temperature and the Sn ratio in the wire composite. (author)

  10. A high field and cryogenic test facility for neutron irradiated superconducting wire

    Science.gov (United States)

    Nishimura, A.; Miyata, H.; Yoshida, M.; Iio, M.; Suzuki, K.; Nakamoto, T.; Yamazaki, M.; Toyama, T.

    2017-12-01

    A 15.5 T superconducting magnet and a variable temperature insert (VTI) system were installed at a radiation control area in Oarai center in Tohoku University to investigate the superconducting properties of activated superconducting materials by fast neutron. The superconductivity was measured at cryogenic temperature and high magnetic field. During these tests, some inconvenient problems were observed and the additional investigation was carried out. The variable temperature insert was designed and assembled to perform the superconducting property tests. without the liquid helium. To remove the heat induced by radiation and joule heating, high purity aluminum rod was used in VTI. The thermal contact was checked by FEM analysis and an additional support was added to confirm the decreasing the stress concentration and the good thermal contact. After the work for improvement, it was affirmed that the test system works well and all troubles were resolved. In this report, the improved technical solution is described and the first data set on the irradiation effect on Nb3Sn wire is presented.

  11. Superconductivity optimization and phase formation kinetics study of internal-Sn Nb{sub 3}Sn superconducting wires

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chaowu

    2007-07-15

    Superconductors Nb{sub 3}Sn wires are one of the most applicable cryogenic superconducting materials and the best choice for high-field magnets exceeding 10 T. One of the most significant utilization is the ITER project which is regarded as the hope of future energy source. The high-Cu composite designs with smaller number of sub-element and non-reactive diffusion barrier, and the RRP (Restacked Rod Process) internal-Sn technology are usually applied for the wire manufacturing. Such designed and processed wires were supplied by MSA/Alstom and WST/NIN in this research. The systematic investigation on internal-Sn superconducting wires includes the optimization of heat treatment (HT) conditions, phase formation and its relation with superconductivity, microstructure analysis, and the phase formation kinetics. Because of the anfractuosity of the configuration design and metallurgical processing, the MF wires are not sufficient for studying a sole factor effect on superconductivity. Therefore, four sets of mono-element (ME) wires with different Sn ratios and different third-element addition were designed and fabricated in order to explore the relationship between phase formation and superconducting performances, particularly the A15 layer growth kinetics. Different characterization technic have been used (magnetization measurements, neutron diffraction and SEM/TEM/EDX analysis). The A15 layer thicknesses of various ME samples were measured and carried out linear and non-linear fits by means of two model equations. The results have clearly demonstrated that the phase formation kinetics of Nb{sub 3}Sn solid-state reaction is in accordance with an n power relation and the n value is increased with the increase of HT temperature and the Sn ratio in the wire composite. (author)

  12. Superconducting wire for the T-15 toroidal magnet

    International Nuclear Information System (INIS)

    Klimenko, E.Yu.; Kruglov, V.S.; Martovetskij, N.N.

    1987-01-01

    Main characteristics of a wire designed for the T-15 toroidal superconducting magnet production are given. The wire with circulation cooling is a twist of 11 niobium-tin wires 1.5 mm in diameter, joined electrolytically by two copper tubes with 3 mm inside diameter. The wire is capable to carry 10 kA current in the 8.5 T induction field. Wire features and structures promote to receive high structural current density in winding: diffuseness of superconducting-to-normal transition increases wire stability, screw symmetry od a current-carrying core provides wire resistance to pulse longitudinal field effect at plasma current disruption, low bronze thermal conductivity in a twist increases stability to outside pulse perturbations

  13. Investigation of wire motion in superconducting magnets

    International Nuclear Information System (INIS)

    Ogitsu, T.; Tsuchiya, K.; Devred, A.

    1990-09-01

    The large Lorentz forces occuring during the excitation of superconducting magnets can provoke sudden motions of wire, which eventually release enough energy to trigger a quench. These wire motions are accompanied by two electromagnetic effects: an induced emf along the moved wire, and a local change in flux caused by the minute dislocation of current. Both effects cause spikes in the coil voltage. Voltage data recorded during the excitation of a superconducting quadrupole magnet which early exhibit such events are here reported. Interpretations of the voltage spikes in terms of energy release are also presented, leading to insights on the spectrum of the disturbances which occur in real magnets. 15 refs

  14. Josephson junction arrays and superconducting wire networks

    International Nuclear Information System (INIS)

    Lobb, C.J.

    1992-01-01

    Techniques used to fabricate integrated circuits make it possible to construct superconducting networks containing as many as 10 6 wires or Josephson junctions. Such networks undergo phase transitions from resistive high-temperature states to ordered low-resistance low-temperature states. The nature of the phase transition depends strongly on controllable parameters such as the strength of the superconductivity in each wire or junction and the external magnetic field. This paper will review the physics of these phase transitions, starting with the simplest zero-magnetic field case. This leads to a Kosterlitz-Thouless transition when the junctions or wires are weak, and a simple mean-field fransition when the junctions or wires are strong. Rich behavior, resulting from frustration, occurs in the presence of a magnetic field. (orig.)

  15. Superconducting magnet wire

    Science.gov (United States)

    Schuller, Ivan K.; Ketterson, John B.; Banerjee, Indrajit

    1986-01-01

    A superconducting tape or wire with an improved critical field is formed of alternating layers of a niobium-containing superconductor such as Nb, NbTi, Nb.sub.3 Sn or Nb.sub.3 Ge with a thickness in the range of about 0.5-1.5 times its coherence length, supported and separated by layers of copper with each copper layer having a thickness in the range of about 170-600 .ANG..

  16. Development of Nb3Sn AC superconducting wire. Pt. 2

    International Nuclear Information System (INIS)

    Kasahara, Hobun; Torii, Shinji; Akita, Shirabe; Ueda, Kiyotaka; Kubota, Yoji; Yasohama, Kazuhiko; Kobayashi, Hisayasu; Ogasawara, Takeshi.

    1993-01-01

    For the realization of superconducting power apparatus, it is important that the development of highly stable superconducting cables. Nb 3 Sn wire has higher critical temperature than NbTi wire. Therefore, it is possible to make highly stable superconducting wires. In this report, we examine a manufacturing process of Ac Nb 3 Sn wire. This manufacturing process has four times higher critical current density than conventional processes. We have made a 400 kVA class AC coil with React and Wind method. The loss density of this coil was 20MW/m 3 at just before the quench. In this case, the temperature of cable increased about 3.8 K. This means that the Nb 3 Sn coil has a very high stability. (author)

  17. High field superconducting magnets

    Science.gov (United States)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  18. Wire rope superconducting cable for diurnal load leveling SMES

    International Nuclear Information System (INIS)

    Costello, G.A.

    1980-01-01

    The design of a wire rope cable for a superconducting magnetic energy storage (SMES) unit is discussed. The superconducting wires in the rope permit the passage of large currents in the relatively small conductors of the windings and hence cause large electromagnetic forces to act on the rope. The diameter of the rope, from a strength point of view, can be considerably reduced by supporting the rope at various points along its length

  19. Development of Fe-based superconducting wires for liquid-hydrogen level sensors

    Science.gov (United States)

    Ishida, S.; Tsuchiya, Y.; Mawatari, Y.; Eisaki, H.; Nakano, A.; Yoshida, Y.

    2017-07-01

    We developed liquid-hydrogen (LH2) level sensors with Ba(Fe1-x Co x )2As2 superconducting wires (Co-Ba122 wires) as their detection elements. We fabricated Co-Ba122 wires with different Co concentrations x by using the powder-in-tube method. The superconducting transition temperatures of the wires were successfully controlled in the range of 20-25 K by changing x from 0.06 to 0.10. The resistance-temperature curves of the wires exhibited sharp superconducting transitions with widths of 0.5-1.0 K. In addition, we performed an operation test of the Co-Ba122 level sensors with LH2. Close correspondence between the output resistance and the actual LH2 level was observed for a sensor equipped with x = 0.09 wire, demonstrating that this sensor can accurately measure LH2 levels.

  20. The Quantum Socket: Wiring for Superconducting Qubits - Part 2

    Science.gov (United States)

    Bejanin, J. H.; McConkey, T. G.; Rinehart, J. R.; Bateman, J. D.; Earnest, C. T.; McRae, C. H.; Rohanizadegan, Y.; Shiri, D.; Mariantoni, M.; Penava, B.; Breul, P.; Royak, S.; Zapatka, M.; Fowler, A. G.

    Quantum computing research has reached a level of maturity where quantum error correction (QEC) codes can be executed on linear arrays of superconducting quantum bits (qubits). A truly scalable quantum computing architecture, however, based on practical QEC algorithms, requires nearest neighbor interaction between qubits on a two-dimensional array. Such an arrangement is not possible with techniques that rely on wire bonding. To address this issue, we have developed the quantum socket, a device based on three-dimensional wires that enables the control of superconducting qubits on a two-dimensional grid. In this talk, we present experimental results characterizing this type of wiring. We will show that the quantum socket performs exceptionally well for the transmission and reflection of microwave signals up to 10 GHz, while minimizing crosstalk between adjacent wires. Under realistic conditions, we measured an S21 of -5 dB at 6 GHz and an average crosstalk of -60 dB. We also describe time domain reflectometry results and arbitrary pulse transmission tests, showing that the quantum socket can be used to control superconducting qubits.

  1. Processing of flexible high-Tc superconducting wires

    International Nuclear Information System (INIS)

    Lee, B.I.; Modi, V.

    1989-01-01

    Wires superconducting at temperatures above 77 K are produced by using YBa 2 Cu 3 O 7 materials. Flexibility was obtained by support from prefabricated fibers or a metallic coating on the extruded YBa 2 Cu 3 O 7 wires. The microstructure, the T c and the critical current densities of the wires were determined. Processing variables and steps are described

  2. Sensing with Superconducting Point Contacts

    Directory of Open Access Journals (Sweden)

    Argo Nurbawono

    2012-05-01

    Full Text Available Superconducting point contacts have been used for measuring magnetic polarizations, identifying magnetic impurities, electronic structures, and even the vibrational modes of small molecules. Due to intrinsically small energy scale in the subgap structures of the supercurrent determined by the size of the superconducting energy gap, superconductors provide ultrahigh sensitivities for high resolution spectroscopies. The so-called Andreev reflection process between normal metal and superconductor carries complex and rich information which can be utilized as powerful sensor when fully exploited. In this review, we would discuss recent experimental and theoretical developments in the supercurrent transport through superconducting point contacts and their relevance to sensing applications, and we would highlight their current issues and potentials. A true utilization of the method based on Andreev reflection analysis opens up possibilities for a new class of ultrasensitive sensors.

  3. Studying superconducting Nb3Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb3Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb3Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  4. Studying superconducting Nb$_{3}$Sn wire

    CERN Multimedia

    AUTHOR|(CDS)2099575

    2015-01-01

    Studying superconducting Nb$_{3}$Sn wire. From the current experience from LHC and HL-LHC we know that the performance requirements for Nb$_{3}$Sn conductor for future circular collider are challenging and should exceed that of present state-of-the-art materials.

  5. Power operated contact apparatus for superconductive circuit

    Energy Technology Data Exchange (ETDEWEB)

    Woods, D.C.; Efferson, K.R.

    1989-10-10

    This patent describes a power operated contact apparatus for extending and retracting one or more electrical leads into and out of a cryostat for making and breaking, at a cryogenic temperature, electrical contact with a superconductive circuit. It comprises at least one rigid elongated lead for extending into a cold space of the cryostat which is at or near a cryogenic temperature. The lead having an inner end and a outer end; a connector fixed at the inner end of the lead for making electrical contact in the cold space with a connector of the superconductive circuit; guide means journaling the lead for allowing the lead to move axially relative to the guide means and sealing against the lead; a foundation for sealed attachment to the cryostat and to the guide means so that the connector on the inner end of the lead is extendable into making electrical contact with the connector of the superconductive circuit in the cold space; power operated means mounted on the foundation and fixed to the outer end of the lead for extending and retracting the lead to and from making electrical contact with the superconductive circuit in the cold space; and means for de-icing the exterior of the leads and guide means when the leads are connected to the superconducting circuit.

  6. Fabrication of superconducting wire using organometallic precursors and infiltration

    International Nuclear Information System (INIS)

    Lee, Y.J.

    1991-01-01

    Organometallic precursors from naphthenic acid and metal nitrates were used for the synthesis of YBCO oxide superconducting compounds. The characteristics of metal naphthenates as organometallic precursors were investigated by IR spectra, viscosity measurements, and infiltration. 123 superconducting compound obtained from 123 naphthenate showed a Tc of 90 degree K and a rather dense and elongated microstructure. Also, the melting behavior of Ba-cuprates which were used for 123 making was studied. A low-temperature melting process was developed to fabricate silver-sheathed superconducting wire with the powder-in-tube method; flowing argon gas is introduced to the system at 930-945 degree C to reduce the melting temperature of the 123 compound without silver sheath melting. It resulted in a 90 degree K Tc superconducting core with dense and locally aligned microstructure. SEM-EDS and XRD analysis, 4-probe resistance and Jc measurements, and carbon-content determinations were carried out to characterize the microstructure, grain alignment, and superconducting properties of the samples

  7. Stabilized superconductive wires

    International Nuclear Information System (INIS)

    Randall, R.N.; Wong, J.

    1976-01-01

    A stable, high field, high current conductor is produced by packing multiple, multi-layer rods of a bronze core and niobium or vanadium inner jacket and copper outer jacket into a pure copper tube or other means for forming a pure copper matrix, sealing, working the packed tube to a wire, and by diffusion, heat treating to form a type II superconducting, Beta-Wolfram structure, intermetallic compound as a layer within each of several filaments derived from the rods. The layer of Beta-Wolfram structure compound may be formed in less than 2 h of diffusion heat treatment in a thickness of 0.5--2μ

  8. Superconductivity

    International Nuclear Information System (INIS)

    Andersen, N.H.; Mortensen, K.

    1988-12-01

    This report contains lecture notes of the basic lectures presented at the 1st Topsoee Summer School on Superconductivity held at Risoe National Laboratory, June 20-24, 1988. The following lecture notes are included: L.M. Falicov: 'Superconductivity: Phenomenology', A. Bohr and O. Ulfbeck: 'Quantal structure of superconductivity. Gauge angle', G. Aeppli: 'Muons, neutrons and superconductivity', N.F. Pedersen: 'The Josephson junction', C. Michel: 'Physicochemistry of high-T c superconductors', C. Laverick and J.K. Hulm: 'Manufacturing and application of superconducting wires', J. Clarke: 'SQUID concepts and systems'. (orig.) With 10 tabs., 128 figs., 219 refs

  9. Composite ceramic superconducting wires for electric motor applications

    Science.gov (United States)

    Halloran, John W.

    1990-07-01

    Several types of HTSC wire have been produced and two types of HTSC motors are being built. Hundreds of meters of Ag- clad wire were fabricated from YBa2Cu3O(7-x) (Y-123) and Bi2Ca2Sr2Cu3O10 (BiSCCO). The dc homopolar motor coils are not yet completed, but multiple turns of wire have been wound on the coil bobbins to characterize the superconducting properties of coiled wire. Multifilamentary conductors were fabricated as cables and coils. The sintered polycrystalline wire has self-field critical current densities (Jc) as high as 2800 A/sq cm, but the Jc falls rapidly with magnetic field. To improve Jc, sintered YBCO wire is melt textured with a continuous process which has produced textures wire up to 0.5 meters long with 77K transport Jc above 11, 770 A/sq cm2 in self field and 2100 A/sq cm2 at 1 telsa. The Emerson Electric dc homopolar HTSC motor has been fabricated and run with conventional copper coils. A novel class of potential very powerful superconducting motors have been designed to use trapped flux in melt textures Y-123 as magnet replicas in an new type of permanent magnet motor. The stator element and part of the rotor of the first prototype machine exist, and the HTSC magnet replica segments are being fabricated.

  10. Method of forming a ceramic superconducting composite wire using a molten pool

    International Nuclear Information System (INIS)

    Geballe, T.H.; Feigelson, R.S.; Gazit, D.

    1991-01-01

    This paper describes a method for making a flexible superconductive composite wire. It comprises: drawing a wire of noble metal through a molten material, formed by melting a solid formed by pressing powdered Bi 2 O 3 , CaCO 3 SrCO 3 and CuO in a ratio of components necessary for forming a Bi-Sr-Ca-Cu-O superconductor, into the solid and sintering at a temperature in the range of 750 degrees - 800 degrees C. for 10-20 hours, whereby the wire is coated by the molten material; and cooling the coated wire to solidify the molten material to form the superconductive flexible composite wire without need of further annealing

  11. AC loss in superconducting wires operating in a wind turbine like generator

    DEFF Research Database (Denmark)

    Seiler, Eugen; Zirngibl, Thomas; Mijatovic, Nenad

    2010-01-01

    We have manufactured a small circular superconducting coil impregnated with epoxy fibreglass. The coil was wound from a Bi-2223/Ag superconducting wire and it was tested in liquid nitrogen at 77 K. Current-voltage characteristic and the AC losses of the coil were measured and compared...

  12. MgB2 superconducting wires basics and applications

    CERN Document Server

    2016-01-01

    The compendium gives a complete overview of the properties of MgB2 (Magnesium Diboride), a superconducting compound with a transition temperature of Tc = 39K, from the fundamental properties to the fabrication of multifilamentary wires and to the presentation of various applications. Written by eminent researchers in the field, this indispensable volume not only discusses superconducting properties of MgB2 compounds, but also describes known preparation methods of thin films and of bulk samples obtained under high pressure methods. A unique selling point of the book is the detailed coverage of various applications based on MgB2, starting with MRI magnets and high current cables, cooled by Helium (He) vapor. High current cables cooled by liquid hydrogen are also highlighted as an interesting alternative due to the shrinking He reserves on earth. Other pertinent subjects comprise permanent magnets, ultrafine wires for space applications and wind generator projects.

  13. Sample of superconducting wiring from the LHC

    CERN Multimedia

    The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair. The cables carry up to 12’500 amps and must withstand enormous electromagnetic forces. At full field, the force on one metre of magnet is comparable to the weight of a jumbo jet. Coil winding requires great care to prevent movements as the field changes. Friction can create hot spots wh...

  14. A New Superconducting Wire for Future Accelerators

    CERN Multimedia

    2006-01-01

    The CARE/NED project has developed a new superconducting wire that can achieve very high currents (1400 amps) at high magnetic fields (12 teslas). Cross-section of the CARE/NED wire produced by SMI. As we prepare to enter a new phase of particle physics with the LHC, technological development is a continuous process to ensure the demands of future research are met. The next generation of colliders and upgrades of the present ones will require significantly larger magnetic fields for bending and focusing the particle beams. NED (Next European Dipole) is one of the projects taking on this challenge to push technology beyond the present limit (see: More about NED). The magnets in the LHC rely on niobium titanium (NbTi) as the superconducting material, with a maximum magnetic field of 8 to 10T (tesla). In order to exceed this limitation, a different material together with the corresponding technology needs to be developed. NED is assessing the suitability of niobium tin (Nb3Sn), which has the potential to at le...

  15. Packaging and interconnection for superconductive circuitry

    International Nuclear Information System (INIS)

    Anacker, W.

    1976-01-01

    A three dimensional microelectronic module packaged for reduced signal propagation delay times including a plurality of circuit carrying means, which may comprise unbacked chips, with integrated superconductive circuitry thereon is described. The circuit carrying means are supported on their edges and have contact lands in the vicinity of, or at, the edges to provide for interconnecting circuitry. The circuit carrying means are supported by supporting means which include slots to provide a path for interconnection wiring to contact the lands of the circuit carrying means. Further interconnecting wiring may take the form of integrated circuit wiring on the reverse side of the supporting means. The low heat dissipation of the superconductive circuitry allows the circuit carrying means to be spaced approximately no less than 30 mils apart. The three dimensional arrangement provides lower random propagation delays than would a planar array of circuits

  16. Theoretical and experimental determination of mechanical properties of superconducting composite wire

    International Nuclear Information System (INIS)

    Gray, W.H.; Sun, C.T.

    1976-07-01

    The mechanical properties of a composite superconducting (NbTi/Cu) wire are characterized in terms of the mechanical properties of each constituent material. For a particular composite superconducting wire, five elastic material constants were experimentally determined and theoretically calculated. Since the Poisson's ratios for the fiber and the matrix material were very close, there was essentially no (less than 1 percent) difference among all the theoretical predictions for any individual mechanical constant. Because of the expense and difficulty of producing elastic constant data of 0.1 percent accuracy, and therefore conclusively determining which theory is best, no further experiments were performed

  17. Method of preparing composite superconducting wire

    International Nuclear Information System (INIS)

    Verhoeven, J. D.; Finnemore, D. K.; Gibson, E. D.; Ostenson, J. E.; Schmidt, F. A.

    1985-01-01

    An improved method of preparing composite multifilament superconducting wire of Nb 3 Sn in a copper matrix which eliminates the necessity of coating the drawn wire with tin. A generalized cylindrical billet of an alloy of copper containing at least 15 weight percent niobium, present in the copper as discrete, randomly distributed and oriented dendritic-shaped particles, is provided with at least one longitudinal opening which is filled with tin to form a composite drawing rod. The drawing rod is then drawn to form a ductile composite multifilament wire containing a filament of tin. The ductile wire containing the tin can then be wound into magnet coils or other devices before heating to diffuse the tin through the wire to react with the niobium forming Nb 3 Sn. Also described is an improved method for making large billets of the copper-niobium alloy by consumable-arc casting

  18. Method of superconducting joint and its measurement

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Lee, Ho Jin; Hong, Gye Won

    1994-04-01

    The development of joint techniques for superconducting wires is essential to fabricate the high quality superconducting magnet. In this report, the various joining methods and their measuring techniques were reviewed. In order to fabricate a precise superconducting magnet, joining and measuring experiment by using the field decay technique carried out. The contact resistance of coupled specimens with joint was measured as 3.0 x 10 -15 ohm at 1 Tesla which is lower than that of the real operating condition of MRI magnet. It is expected that these data can be used to design and fabricate the superconducting magnets successfully. (Author) 12 refs., 20 figs., 2 tabs

  19. Pb induces superconductivity in Bi2Se3 analyzed by point contact spectroscopy

    OpenAIRE

    Arevalo-López, P.; López-Romero, R. E.; Escudero, R.

    2015-01-01

    Some topological insulators become superconducting when doped with Cu and Pd. Superconductivity in a non-superconductor may be induced by proximity effect: i.e. Contacting a non-superconductor with a superconductor. The superconducting macroscopic wave function will induce electronic pairing into the normal compound. In the simplest topological insulator, Bi$_2$Se$_3$, superconductivity may be induced with Pb. We studied with point contact junctions formed by contacting Bi$_2$Se$_3$ crystals ...

  20. Development of a new type of three-component composite superconducting wire

    International Nuclear Information System (INIS)

    Onishi, T.

    1977-01-01

    A new type of multifilamentary composite superconducting wire is described. This wire consists of seven filaments, each of which is a fine tubular Nb 50% Ti wire, filled with high purity aluminium and embedded in a cupronickel matrix. The results of experiments carried out on the stability and ac losses of this wire are presented. (author)

  1. Zero-bias conductance quantization in a normal / superconducting junction of nano wire

    International Nuclear Information System (INIS)

    Asano, Yasuhiro; Tanaka, Yukio

    2012-01-01

    We discuss a strong relationship between Majorana fermions and odd-frequency Cooper pairs which appear at a disordered normal nano wire attached to a topologically nontrivial superconducting one. The zero-bias differential conductance in a normal / superconducting nano wire junctions is quantized at 2e 2 /h irrespective of degree of disorder, length of disordered segment, and random realization of disordered potential. Such behaviors are exactly the same as those in the anomalous proximity effect of p x -wave spin-triplet superconductors. We show that odd-frequency Cooper pairs assist the unusual transport properties.

  2. Improved superconducting magnet wire

    Science.gov (United States)

    Schuller, I.K.; Ketterson, J.B.

    1983-08-16

    This invention is directed to a superconducting tape or wire composed of alternating layers of copper and a niobium-containing superconductor such as niobium of NbTi, Nb/sub 3/Sn or Nb/sub 3/Ge. In general, each layer of the niobium-containing superconductor has a thickness in the range of about 0.05 to 1.5 times its coherence length (which for Nb/sub 3/Si is 41 A) with each copper layer having a thickness in the range of about 170 to 600 A. With the use of very thin layers of the niobium composition having a thickness within the desired range, the critical field (H/sub c/) may be increased by factors of 2 to 4. Also, the thin layers of the superconductor permit the resulting tape or wire to exhibit suitable ductility for winding on a magnet core. These compositions are also characterized by relatively high values of critical temperature and therefore will exhibit a combination of useful properties as superconductors.

  3. High-Tc superconducting electric motors

    International Nuclear Information System (INIS)

    Schiferl, R.; Stein, J.

    1992-01-01

    In this paper, the advantages and limitations of using superconductors in motors are discussed. A synchronous motor with a high temperature superconducting field winding for pump and fan drive applications is described and some of its unique design features are identified. A 10,000 horsepower superconducting motor design is presented. The critical field and current density requirements for high temperature superconducting wire in motors is discussed. Finally, recent progress in superconducting wire performance is presented

  4. A vibrating wire parallel to a high temperature superconducting slab. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Saif, A G; El-sabagh, M A [Department of Mathematic and Theoretical physics, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The power losses problem for an idealized high temperature type II superconducting system of a simple geometry is studied. This system is composed of a vibrating normal conducting wire (two wires) carrying a direct current parallel to an uniaxial anisotropic type II superconducting slab (moving slab). First, the electromagnetic equation governing the dynamics of this system, and its solutions are obtained. Secondly, a modified anisotropic london equation is developed to study these systems in the case of the slab moving. Thirdly, it is found that, the power losses is dependent on the frequency, london penetration depth, permeability, conductivity, velocity, and the distance between the normal conductors and the surfaces of the superconducting slab. Moreover, the power losses decreases as the distance between the normal conductors and the surface of the superconducting slab decreases; and increases as the frequency, the london penetration depth, permeability, conductivity, and velocity are increased. These losses along the versor of the anisotropy axis is increased as {lambda}{sub |}| increases. Moreover, it is greater than the power losses along the crystal symmetry direction. In the isotropic case as well as the slab thickness tends to infinity, agreement with previous results are obtained. 2 figs.

  5. Superconducting technology

    International Nuclear Information System (INIS)

    2010-01-01

    Superconductivity has a long history of about 100 years. Over the past 50 years, progress in superconducting materials has been mainly in metallic superconductors, such as Nb, Nb-Ti and Nb 3 Sn, resulting in the creation of various application fields based on the superconducting technologies. High-T c superconductors, the first of which was discovered in 1986, have been changing the future vision of superconducting technology through the development of new application fields such as power cables. On basis of these trends, future prospects of superconductor technology up to 2040 are discussed. In this article from the viewpoints of material development and the applications of superconducting wires and electronic devices. (author)

  6. A new wire fabrication processing using high Ga content Cu-Ga compound in V3Ga compound superconducting wire

    International Nuclear Information System (INIS)

    Hishinuma, Yoshimitsu; Nishimura, Arata; Kikuchi, Akihiro; Iijima, Yasuo; Takeuchi, Takao

    2007-01-01

    A superconducting magnet system is also one of the important components in an advanced magnetic confinement fusion reactor. Then it is required to have a higher magnetic field property to confine and maintain steady-sate burning deuterium (D)-tritium (T) fusion plasma in the large interspace during the long term operation. Burning plasma is sure to generate 14 MeV fusion neutrons during deuterium-tritium reaction, and fusion neutrons will be streamed and penetrated to superconducting magnet through large ports with damping neutron energy. Therefore, it is necessary to consider carefully not only superconducting property but also neutron irradiation property in superconducting materials for use in a future fusion reactor, and a 'low activation and high field superconducting magnet' will be required to realize the fusion power plant beyond International Thermonuclear Experimental Reactor (ITER). V-based superconducting material has a much shorter decay time of induced radioactivity compared with the Nb-based materials. We thought that the V 3 Ga compound was one of the most promising materials for the 'low activation and higher field superconductors' for an advanced fusion reactor. However, the present critical current density (J c ) property of V 3 Ga compound wire is insufficient for apply to fusion magnet applications. We investigated a new route PIT process using a high Ga content Cu-Ga compound in order to improve the superconducting property of the V 3 Ga compound wire. (author)

  7. Quality analysis of superconducting wire and cable for SSC dipole magnets

    International Nuclear Information System (INIS)

    Pollock, D.A.

    1992-01-01

    This paper reports that a critical component of the SSC collider dipole magnets is superconducting cable. The uniformity and reliability requirements for the dipoles place stringent demands on the cable. These needs have been defined as various contract requirements in the material specifications for NbTi alloy, superconducting wire and cable. A supplied qualification program is being started by the SSCL with industry to establish reliable sources of superconductor cable. Key to this qualification program is the establishment by industry of detailed process methods and controls for wire and cable manufacture. To monitor conductor performance, a computer database is being developed by the SSCL Magnet Systems Division Quality Assurance Department. The database is part of a program for ensuring superconductor uniformity by focusing on the understanding and control of variation. A statistical and graphical summary of current data for key performance variables will be presented in light of the specification requirement for uniformity. Superconductor material characteristics to be addressed will include Wire Critical Current (I c ), Copper Ratio (Cu:SC), Wire Diameter, Wire Piece Length, and Cable Dimensional Control

  8. Composite superconducting wires produced by rapid coating in Bi-Sr-Ca-Cu-O metal oxide system

    International Nuclear Information System (INIS)

    Grozav, A.D.; Konopko, L.A.; Leoporda, N.I.

    1989-01-01

    Method for producing superconducting composite wires by dip coating of copper wires in metal-oxide BiSrCaCu 2 O x melt is developed. The thickness of the coating is regulated by the change of dip rate, melt viscosity and by the number of passages through the melt. Wire annealing at 700-800 deg C leads to the production of two phases, one of them being superconducting with T c =80K

  9. Technology development of fabrication NbTi and Nb3 Sn superconducting wires

    International Nuclear Information System (INIS)

    Rodrigues Junior, D.; Bormio, C.; Baldan, C.A.; Ramos, M.J.; Pinatti, D.G.

    1988-01-01

    The technology development of NbTi and Nb 3 Sn superconducting wires are studied, mentioning the use of fluxes capture theory in the sizing of wires fabrication. The fabrication process, the thermal treatment and the experimental datas of critical temperature and current of Nb 3 Sn wires are described. (C.G.C.) [pt

  10. Development of a short sample test facility for evaluating superconducting wires

    International Nuclear Information System (INIS)

    Singh, M.R.; Kulkarni, D.G.; Sahni, V.C.; Ravikumar, G.; Patel, K.L.

    2002-01-01

    In this paper we describe a short sample test facility we have set up at Bhabha Atomic Research Centre (BARC). This facility has been used to measure critical currents of NbTi/Cu composite superconducting wires by recording V versus I data at 4.2 K. It offers sample current as large as 1500 A and a transverse magnetic field up to 7.4 T. A power law, V ∼I n( H) is fitted to the resistive transition region to estimate the exponent n, which is a measure of the uniformity of superconducting filaments in composite wires. It is observed that inadequate thermal stabilization of sample wire results in thermal runaway, which limits the V-I data to∼ 2μ V . This in turn affects the reliability of estimated filament uniformity. To mitigate this problem, we have used a sample holder made of OFHC-Cu which enhances thermal stabilization of the sample. With this sample holder, the results of measurements carried out on wires developed by the Atomic Fuel Division, BARC show a high filament uniformity (n ∼ 58). (author)

  11. The Quantum Socket: Wiring for Superconducting Qubits - Part 3

    Science.gov (United States)

    Mariantoni, M.; Bejianin, J. H.; McConkey, T. G.; Rinehart, J. R.; Bateman, J. D.; Earnest, C. T.; McRae, C. H.; Rohanizadegan, Y.; Shiri, D.; Penava, B.; Breul, P.; Royak, S.; Zapatka, M.; Fowler, A. G.

    The implementation of a quantum computer requires quantum error correction codes, which allow to correct errors occurring on physical quantum bits (qubits). Ensemble of physical qubits will be grouped to form a logical qubit with a lower error rate. Reaching low error rates will necessitate a large number of physical qubits. Thus, a scalable qubit architecture must be developed. Superconducting qubits have been used to realize error correction. However, a truly scalable qubit architecture has yet to be demonstrated. A critical step towards scalability is the realization of a wiring method that allows to address qubits densely and accurately. A quantum socket that serves this purpose has been designed and tested at microwave frequencies. In this talk, we show results where the socket is used at millikelvin temperatures to measure an on-chip superconducting resonator. The control electronics is another fundamental element for scalability. We will present a proposal based on the quantum socket to interconnect a classical control hardware to a superconducting qubit hardware, where both are operated at millikelvin temperatures.

  12. Possibility of material cost reduction toward development of low-cost second-generation superconducting wires

    Science.gov (United States)

    Ichinose, Ataru; Horii, Shigeru; Doi, Toshiya

    2017-10-01

    Two approaches to reducing the material cost of second-generation superconducting wires are proposed in this paper: (1) instead of the electrical stabilizing layers of silver and copper presently used on the superconducting layer, a Nb-doped SrTiO3 conductive buffer layer and cube-textured Cu are proposed as an advanced architecture, and (2) the use of an electromagnetic (EM) steel tape as a metal substrate of coated conductors in a conventional architecture. In structures fabricated without using electrical stabilizing layers on the superconducting layer, the critical current density achieved at 77 K in a self-field was approximately 2.6 MA/cm2. On the other hand, in the case of using EM steel tapes, although the critical current density was far from practical at the current stage, the biaxial alignment of YBa2Cu3O y (YBCO) and buffer layers was realized without oxidation on the metal surface. In this study, the possibility of material cost reduction has been strongly indicated toward the development of low-cost second-generation superconducting wires in the near future.

  13. Current contact device for a superconducting magnet coil

    International Nuclear Information System (INIS)

    Hieronymus, H.

    1987-01-01

    The invention concerns a current supply device for a superconducting magnet coil to be shortcircuited, with a separating device per coil end, which contains a fixed cooled contact and a moving contact connected to a power supply device and a mechanical actuating device for closing and opening the contacts. When closing the heated contact on to the cooled contact, relatively large quantities of heat can be transferred to the cooled contact and therefore to the connected superconducting coil end and can cause normal conduction there. The invention therefore provides that the mass ratio of the cooled contact to the moving contact is at least 5:1, preferably at least 10:1, and that the cooled contact part is provided, at the end away from the contact area, with means for increasing the area, for example cooling fins and is connected to the coil end has a thermal resistance between the contact area and the coil end of at least 0.2 k/W, preferably at least 0.5 k/W per 1000 A of current to be transmitted. (orig.) [de

  14. Superconducting magnet

    Science.gov (United States)

    1985-01-01

    Extensive computer based engineering design effort resulted in optimization of a superconducting magnet design with an average bulk current density of approximately 12KA/cm(2). Twisted, stranded 0.0045 inch diameter NbTi superconductor in a copper matrix was selected. Winding the coil from this bundle facilitated uniform winding of the small diameter wire. Test coils were wound using a first lot of the wire. The actual packing density was measured from these. Interwinding voltage break down tests on the test coils indicated the need for adjustment of the wire insulation on the lot of wire subsequently ordered for construction of the delivered superconducting magnet. Using the actual packing densities from the test coils, a final magnet design, with the required enhancement and field profile, was generated. All mechanical and thermal design parameters were then also fixed. The superconducting magnet was then fabricated and tested. The first test was made with the magnet immersed in liquid helium at 4.2K. The second test was conducted at 2K in vacuum. In the latter test, the magnet was conduction cooled from the mounting flange end.

  15. Survey of potential applications of superconducting suspensions

    International Nuclear Information System (INIS)

    Rao, D.K.; Bupara, S.S.

    1993-01-01

    The purpose of this report is to survey the recent developments in applying the bulk superconductors to mechanical applications. These applications, called superconducting suspensions, can be broadly divided into three groups - Passive Magnetic Bearings, Passive Superconducting Dampers and Active Superconducting Bearings. Basically, passive magnetic bearings utilize bulk superconductors to support a rotating shaft without contact while active superconducting bearings employ superconducting wires. Passive superconducting dampers, on the other hand, dissipate energy from a vibrating component. Over the past one year, dramatic improvements have been made in processing large-size specimens made of high grade bulk superconductors. As a result, they can meet the size requirements and load capacity requirements of many applications. With this size-scale up, one can utilize them in a wider number of applications than what was possible a few years back. At present several organizations have demonstrated the capability of passive magnetic bearings. The targeted applications include miniature cryoturboexpanders, cryoturbopumps, energy storage wheels and turbomolecular pumps. These demonstrations indicate that the passive magnetic bearings are closer to technology maturity. (orig.)

  16. Quantum suppression of superconductivity in nanowires

    International Nuclear Information System (INIS)

    Bezryadin, Alexey

    2008-01-01

    It is of fundamental importance to establish whether there is a limit to how thin a superconducting wire can be, while retaining its superconducting character-and if there is such limit, to understand what determines it. This issue may be of practical importance in defining the limit to miniaturization of superconducting electronic circuits. Recently, a new fabrication method, called molecular templating, was developed and used to answer such questions. In this approach, a suspended carbon nanotube is coated with a thin superconducting metal film, thus forming a superconducting nanowire. The wire obtained is automatically attached to the two leads formed by the sides of the trench. The usual material for such wires is the amorphous alloy of MoGe (Graybeal 1985 PhD Thesis Stanford University; Graybeal and Beasley 1984 Phys. Rev. B 29 4167; Yazdani and Kapitulnik 1995 Phys. Rev. Lett. 74 3037; Turneaure et al 2000 Phys. Rev. Lett. 84 987). Such wires typically exhibit a high degree of homogeneity and can be made very small: as thin as ∼5 nm in diameter and as short as ∼40 nm in length. The results of transport measurements on such homogeneous wires can be summarized as follows. Short wires, shorter than some empirical length, ∼200 nm for MoGe, exhibit a clear dichotomy. They show either a superconducting behavior, with the resistance controlled by thermal fluctuations, or a weakly insulating behavior, with the resistance controlled by the weak Coulomb blockade. Thus a quantum superconductor-insulator transition (SIT) is indicated. Longer wires exhibit a gradual crossover behavior, from almost perfectly superconducting to normal or weakly insulating behavior, as their diameter is reduced. Measurements of wires, which are made inhomogeneous (granular) on purpose, show that such wires, even if they are short in the sense stated above, do not show a clear dichotomy, which could be identified as an SIT (Bollinger et al 2004 Phys. Rev. B 69 180503(R)). Thus

  17. Fabrication and superconducting properties of a simple-structured jelly-roll Nb{sub 3}Al wire with low-temperature heat-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cui, L.J. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Yan, G., E-mail: gyan@c-wst.com [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Pan, X.F. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Zhang, P.X. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Northwest Institute for Nonferrous Metal Research (NIN), Xi’an 710016 (China); Qi, M. [Northwest Institute for Nonferrous Metal Research (NIN), Xi’an 710016 (China); Liu, X.H.; Feng, Y. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Chen, Y.L.; Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Superconductivity and New Energy R& D Center, Southwest Jiaotong University (SWJTU), Chengdu 610031 (China)

    2015-06-15

    Highlights: • Nb{sub 3}Al superconducting wires with Cu-matrix and different filament numbers were prepared by the jelly-roll method. • The length of 18-cores Nb{sub 3}Al superconducting wire reaches 100 m without any breakage and intermediate anneal. • This wire has the uniform filament-shapes and fine long-wire homogeneity. • This Nb{sub 3}Al long wire has the T{sub c} of 13.4 K and J{sub c} of 4.7 × 10{sup 4} A/cm{sup 2} at 4.2 K and 12 T. - Abstract: With extremely high critical current density (J{sub c}) and excellent strain tolerance, Nb{sub 3}Al superconductor is considered as an alternative to Nb{sub 3}Sn for application of high-field magnets. However, owing to their complex structure, Nb{sub 3}Al superconducting wires can hardly meet the requirement of engineering application at present. In this work, a novel simple-structured Nb{sub 3}Al superconducting wires with Cu-matrix and different filament numbers were prepared by the conventional jelly-roll method, as well as a heat-treatment of 800–850 °C for 20–50 h. The results show that a 18-filament superconducting wire with length longer than 100 m can be successfully prepared by this method, and also this Nb{sub 3}Al long wire has the T{sub c} of 13.4 K and J{sub c} of 4.7 × 10{sup 4} A/cm{sup 2} at 4.2 K and 12 T. These suggest that with further optimization, the simple-structured Nb{sub 3}Al superconducting wires are very promising to fabricate the km-grade long wires to meet the requirement of engineering application.

  18. Analysis of mechanical characteristics of superconducting field coil for 17 MW class high temperature superconducting synchronous motor

    International Nuclear Information System (INIS)

    Kim, J. H.; Park, S. I.; Im, S. H.; Kim, H. M.

    2013-01-01

    Superconducting field coils using a high-temperature superconducting (HTS) wires with high current density generate high magnetic field of 2 to 5 [T] and electromagnetic force (Lorentz force) acting on the superconducting field coils also become a very strong from the point of view of a mechanical characteristics. Because mechanical stress caused by these powerful electromagnetic force is one of the factors which worsens the critical current performance and structural characteristics of HTS wire, the mechanical stress analysis should be performed when designing the superconducting field coils. In this paper, as part of structural design of superconducting field coils for 17 MW class superconducting ship propulsion motor, mechanical stress acting on the superconducting field coils was analyzed and structural safety was also determined by the coupling analysis system that is consists of commercial electromagnetic field analysis program and structural analysis program.

  19. Electromechanical characterization of superconducting wires and tapes at 77 K

    CERN Document Server

    Bjoerstad, Roger

    The strain dependency of the critical current in state-of-the-art cuprate high-temperature superconductors (HTS) has been characterized. A universal test machine (UTM) combined with a critical current measurement system has been used to characterize the mechanical and the superconducting properties of conductors immersed in an open liquid nitrogen dewar. A set-up has been developed in order to perform simultaneous measurements of the superconductor lattice parameter changes, critical current, as well as the stress and strain at 77 K in self-field in a high energy synchrotron beamline. The HTS tapes and wires studied were based on YBCO, Bi-2223 and Bi-2212. The YBCO tapes were produced by SuperPower and American Superconductors (AMSC). Two types of Bi-2223 tapes, HT and G, were produced by Sumitomo Electric Industries (SEI). The Bi-2212 wires were produced by Oxford Superconducting Technology (OST) using Nexans granulate precursor, before undergoing a specialized over pressure (OP) processing and heat treatmen...

  20. Recent progress in methods for non-invasive measurements of local strain in practical superconducting wires and conductors using quantum beam techniques

    International Nuclear Information System (INIS)

    Osamura, Kozo; Machiya, Shutaro; Tsuchiya, Yoshinori; Suzuki, Hiroshi; Awaji, Satoshi; Takahashi, Kohki; Oguro, Hidetoshi; Harjo, Stefanus; Hemmi, Tsutomu; Nakamoto, Tatsushi; Sugano, Michinaka; Jin, Xinzhe; Kajiwara, Kentaro

    2014-01-01

    Practical superconducting wires are designed with a composite structure to meet the desired engineering characteristics by expert selection of materials and design of the architecture. In practice, the local strain exerted on the superconducting component influences the electromagnetic properties. Here, recent progress in methods used to measure the local strain in practical superconducting wires and conductors using quantum beam techniques is introduced. Recent topics on the strain dependence of critical current are reviewed for three major practical wires: ITER-Nb 3 Sn strand, DI-BSCCO wires and REBCO tapes. (author)

  1. Superconducting properties of powder-metallurgically produced Cu-Nb3Sn composite wires

    International Nuclear Information System (INIS)

    Schaper, W.; Wecker, J.; Heine, K.; Bormann, R.; Freyhardt, H.C.

    1988-01-01

    The critical current density of composite superconducting wires can be improved by ternary or quaternary additions. If these additions are incorporated into the A15 phase the upper critical field can be increased. An increase in this field, however, can only be realized if the additions do not strongly deteriorate the critical temperature. An enhanced upper critical field in connection with a favorable grain size of the A15 phase finally leads to improved critical current densities in the entire field range. With these parameters as guidelines, the effects of Ti, In, Ga, and Ge additions to the bronze and of Ta additions to the niobium on the superconducting properties of PM produced Cu-Nb 3 Sn wires were investigated

  2. Young's modulus of a copper-stabilized niobium-titanium superconductive wire

    International Nuclear Information System (INIS)

    Ledbetter, H.M.; Moulder, J.C.; Austin, M.W.

    1980-01-01

    Young's modulus was determined for a 0.6-mm-dia niobium-titanium superconductive wire. Two methods were used: continuous-wave-resonance and laser-pulse-excitation. Young's moduli were also determined for the components - copper and Nb-Ti - in both wire and bulk forms. Some mechanical-deformation effects on Young's modulus were also measured. From the component' elastic moduli, that of the composite was predicted accurately by a simple rule-of-mixtures relationship

  3. Resistive transition of superconducting-wire networks. Influence of pinning and fluctuations

    International Nuclear Information System (INIS)

    Giroud, M.; Buisson, O.; Wang, Y.Y.; Pannetier, B.; Mailly, D.

    1992-01-01

    The authors studied the resistive transition of several 2-D superconducting-wire networks of various coupling strengths, which they characterize in terms of the Kosterlitz-Thouless transition temperature and the ratio ξ/a of the coherence length to the array period. In the extreme strong-coupling limit where the mesh size is of the order of the zero-temperature coherence length, the superconducting behavior is well described by the mean-field properties of the superconducting wave function. Extending to 2-D array, the 1-D phase-slippage model explains the dissipative regime observed above the Ginzburg-Landau depairing critical current. On the other hand, when the coupling is weak, phase fluctuations below the Ginzburg-Landau transition and vortex depinning dominate the resistive behavior. An activated dissipation is observed even below the depairing critical current. Results obtained in this regime for critical temperature, magnetoresistance, or critical current versus temperature, and magnetic field are shown; their periodic oscillations are discussed in terms of depinning of vortices on the array. A simple periodic pinning potential for a vortex in a wire network is calculated, and compared with the case of pinning in Josephson junction arrays. It is shown that this model explains qualitatively the experimental results observed for small ξ/a

  4. Characterization of NbTi multifilamentary superconducting wires

    International Nuclear Information System (INIS)

    Vellego, G.

    1988-01-01

    Pirelli is developing superconducting mulfilamentary NbTi wires, with current carrying capacities of up to 500 A, for use in magnetic resonance imaging (MRI) systems and in small research magnets. Pirelli and IFUSP have developed a system for assessing wire performance, whose quality is comparable to the equivalent systems at the Brookhaven National Laboratory (BNL) and at the National Bureau of Standards (NBS). In particular, a high sensitivity is required for critical current measurements, so that the modern criteria for definition of critical current can be used. These involve conductor resistivities of the order of 10 -12 ohm-cm. The methods of measurements of critical current in applied magnetic fields, of residual resistance ratio and of copper to superconductor ratio are described. The results of the first tests performed in Pirelli wires and in wires of other manufacturers are described. These include tests on a NBS standard reference material. These results are of the same quality as results obtained at BNL or NBS on the same wires. So this system can be very useful throughout the Pirelli program. (author) [pt

  5. Composite superconducting MgB2 wires made by continuous process

    NARCIS (Netherlands)

    Kutukcu, Mehmet; Atamert, Serdar; Scandella, Jean Louis; Hopstock, Ron; Blackwood, Alexander C.; Dhulst, Chris; Mestdagh, Jan; Nijhuis, Arend; Glowacki, Bartek A.

    Previously developed manufacturing technology of a low-cost composite single core MgB2 superconductive wires has been investigated in details using monel sheath and titanium diffusion barrier. In this process Mg and nano-sized B as well as SiC dopant powders were fed continuously to a "U" shaped

  6. Composite superconducting MgB2 wires made by continuous process

    NARCIS (Netherlands)

    Kutukcu, Mehmet; Atamert, Serdar; Scandella, Jean Louis; Hopstock, Ron; Blackwood, Alexander C.; Dhulst, Chris; Mestdagh, Jan; Nijhuis, Arend; Glowacki, Bartek A.

    2018-01-01

    Previously developed manufacturing technology of a low-cost composite single core MgB2 superconductive wires has been investigated in details using monel sheath and titanium diffusion barrier. In this process Mg and nano-sized B as well as SiC dopant powders were fed continuously to a "U" shaped

  7. Textured YBCO films grown on wires: application to superconducting cables

    International Nuclear Information System (INIS)

    Dechoux, N; Jiménez, C; Chaudouët, P; Rapenne, L; Sarigiannidou, E; Robaut, F; Petit, S; Garaudée, S; Porcar, L; Soubeyroux, J L; Odier, P; Bruzek, C E; Decroux, M

    2012-01-01

    Efforts to fabricate superconducting wires made of YBa 2 Cu 3 O 7 (YBCO) on La 2 Zr 2 O 7 (LZO) buffered and biaxially textured Ni-5 at.%W (NiW) are described. Wires were manually shaped from LZO buffered NiW tapes. Different diameters were produced: 1.5, 2 and 3 mm. The wires were further covered with YBCO grown by metal organic chemical vapor deposition (MOCVD). We developed an original device in which the round substrate undergoes an alternated rotation of 180° around its axis in addition to a reel-to-reel translation. This new approach allows covering the whole circumference of the wire with a YBCO layer. This was confirmed by energy dispersive x-ray spectroscopy (EDX) analysis coupled to a scanning electron microscope (SEM). For all wire diameters, the YBCO layer thickness varied from 300 to 450 nm, and the cationic composition was respected. Electron backscattering diffraction (EBSD) measurements were performed directly on an as-deposited wire without surface preparation allowing the investigation of the crystalline quality of the film surface. Combining EBSD with XRD results we show that YBCO grows epitaxially on the LZO buffered NiW wires. For the first time, superconductive behaviors have been detected on round substrates in both the rolling and circular direction. J c reached 0.3 MA cm −2 as measured at 77 K by transport and third-harmonic detection. Those preliminary results confirm the effectiveness of the MOCVD for complex geometries, especially for YBCO deposition on small diameter wires. This approach opens huge perspectives for the elaboration of a new generation of YBCO-based round conductors. (paper)

  8. Ductile alloy and process for preparing composite superconducting wire

    Science.gov (United States)

    Verhoeven, J.D.; Finnemore, D.K.; Gibson, E.D.; Ostenson, J.E.

    An alloy for the commercial production of ductile superconducting wire is prepared by melting together copper and at least 15 weight percent niobium under non-oxygen-contaminating conditions, and rapidly cooling the melt to form a ductile composite consisting of discrete, randomly distributed and oriented dendritic-shaped particles of niobium in a copper matrix. As the wire is worked, the dendritic particles are realigned parallel to the longitudinal axis and when drawn form a plurality of very fine ductile superconductors in a ductile copper matrix. The drawn wire may be tin coated and wound into magnets or the like before diffusing the tin into the wire to react with the niobium. Impurities such as aluminum or gallium may be added to improve upper critical field characteristics.

  9. New analytical results in the electromagnetic response of composite superconducting wire in parallel fields

    NARCIS (Netherlands)

    Niessen, E.M.J.; Niessen, E.M.J.; Zandbergen, P.J.

    1993-01-01

    Analytical results are presented concerning the electromagnetic response of a composite superconducting wire in fields parallel to the wire axis, using the Maxwell equations supplemented with constitutive equations. The problem is nonlinear due to the nonlinearity in the constitutive equation

  10. Process for producing clad superconductive materials

    International Nuclear Information System (INIS)

    Cass, R.B.; Ott, K.C.; Peterson, D.E.

    1992-01-01

    This patent describes a process for fabricating superconducting composite wire. It comprises placing a superconductive precursor admixture capable of undergoing self propagating combustion in stoichiometric amounts sufficient to form a superconductive product within an oxygen-porous metal tube; sealing one end of the tube; igniting the superconductive precursor admixture whereby the superconductive precursor admixture endburns along the length of the admixture; and cross-section reducing the tube at a rate substantially equal to the rate of burning of the superconductive precursor admixture and at a point substantially planar with the burnfront of the superconductive precursor mixture, whereby a clad superconductive product is formed in situ

  11. Manufacture of keystoned flat superconducting cables for use in SSC [Superconducting Super Collider] dipoles

    International Nuclear Information System (INIS)

    Royet, J.; Scanlan, R.M.

    1986-09-01

    The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. In this paper we will emphasize the differences between the techniques for cabling conventional wires for cabling superconducting wires. Concepts for the tooling will be introduced. The effects of cabling parameters on critical current degradation are being evaluated in collaboration with NBS-Boulder

  12. Development of superconducting wire and cable for the SSC project in Sumitomo Electric Industries

    International Nuclear Information System (INIS)

    Sashida, T.; Saito, S.; Oku, G.; Kurimoto, K.; Yamada, Y.; Yokota, M.; Ohmatsu, K.; Nagata, M.

    1991-01-01

    As a large production volume of NbTi superconducting wire and cable is required for the SSC project, a production process has been developed at Sumitomo Electric to optimize critical variables of wire properties. To achieve high electrical properties and a high overall yield of NbTi alloy in the fabrication process, the authors have employed carefully designed large size multifilament billets weighing more than 350kg to decrease the number of billets in large production scale. The collider dipole magnet consists of inner and outer cables, and the cable should be as uniform as possible to ensure the performance of the magnets. The authors studied two aspects to obtain such uniformity of superconducting wire; one is the selection of unit weight and the other is the property of critical current density of a strand

  13. Thermal anchoring of wires in large scale superconducting coil test experiment

    International Nuclear Information System (INIS)

    Patel, Dipak; Sharma, A.N.; Prasad, Upendra; Khristi, Yohan; Varmora, Pankaj; Doshi, Kalpesh; Pradhan, S.

    2013-01-01

    Highlights: • We addressed how thermal anchoring in large scale coil test is different compare to small cryogenic apparatus? • We did precise estimation of thermal anchoring length at 77 K and 4.2 K heat sink in large scale superconducting coil test experiment. • We addressed, the quality of anchoring without covering entire wires using Kapton/Teflon tape. • We obtained excellent results in temperature measurement without using GE Varnish by doubling estimated anchoring length. -- Abstract: Effective and precise thermal anchoring of wires in cryogenic experiment is mandatory to measure temperature in milikelvin accuracy and to avoid unnecessary cooling power due to additional heat conduction from room temperature (RT) to operating temperature (OT) through potential, field, displacement and stress measurement instrumentation wires. Instrumentation wires used in large scale superconducting coil test experiments are different compare to cryogenic apparatus in terms of unique construction and overall diameter/area due to errorless measurement in large time-varying magnetic field compare to small cryogenic apparatus, often shielded wires are used. Hence, along with other variables, anchoring techniques and required thermal anchoring length are entirely different in this experiment compare to cryogenic apparatus. In present paper, estimation of thermal anchoring length of five different types of instrumentation wires used in coils test campaign at Institute for Plasma Research (IPR), India has been discussed and some temperature measurement results of coils test campaign have been presented

  14. Superconducting energy gap of YB6 studied by point-contact spectroscopy

    International Nuclear Information System (INIS)

    Szabo, Pavol; Kacmarcik, Jozef; Samuely, Peter; Girovsky, Jan; Gabani, Slavomir; Flachbart, Karol; Mori, Takao

    2007-01-01

    Yttrium hexaboride has the second highest critical temperature, T c ∼ 8 K, among all borides. The presented paper deals with the experimental study of its superconducting energy gap established by the method of the point-contact spectroscopy. The temperature dependence of the energy gap and the strength of the superconducting coupling is presented

  15. Method and apparatus for forming high-critical-temperature superconducting layers on flat and/or elongated substrates

    Science.gov (United States)

    Ciszek, Theodore F.

    1994-01-01

    An elongated, flexible superconductive wire or strip is fabricated by pulling it through and out of a melt of metal oxide material at a rate conducive to forming a crystalline coating of superconductive metal oxide material on an elongated, flexible substrate wire or strip. A coating of crystalline superconductive material, such as Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8, is annealed to effect conductive contact between adjacent crystalline structures in the coating material, which is then cooled to room temperature. The container for the melt can accommodate continuous passage of the substrate through the melt. Also, a second pass-through container can be used to simultaneously anneal and overcoat the superconductive coating with a hot metallic material, such as silver or silver alloy. A hollow, elongated tube casting method of forming an elongated, flexible superconductive wire includes drawing the melt by differential pressure into a heated tubular substrate.

  16. Peak effect and superconducting properties of SmFeAsO{sub 0.8}F{sub 0.2} wires

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y L; Cui, Y J; Yang, Y; Zhang, Y; Wang, L; Zhao, Y [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, and Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C H; Sorrell, C [School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)], E-mail: yzhao@swjtu.edu.cn

    2008-11-15

    Ta-sheathed SmFeAsO{sub 0.8}F{sub 0.2} superconducting wires with T{sub c} = 52.5 K have been fabricated using the powder-in-tube (PIT) method and the superconducting properties of the wires have been investigated. The wires exhibit a very large intragrain critical current density at a temperature below 30 K. A peak effect with maximal J{sub c} = 0.6 MA cm{sup -2} at 10 K under 6 T field was observed. The peak field H{sub pear} is strongly temperature-dependent. A severe weak-link effect depresses the development of global supercurrent owing to a very short coherence length. The wires also show a power law temperature dependence for the irreversibility line with H{sub irr}{approx_equal}(1-T/T{sub c}){sup 1.5}. The H-T phase diagram was found to be similar to that of other superconducting cuprates.

  17. Superconducting technology program Sandia 1996 annual report

    International Nuclear Information System (INIS)

    Roth, E.P.

    1997-02-01

    Sandia's Superconductivity Technology Program is a thallium-based high-temperature superconductor (HTS) research and development program consisting of efforts in powder synthesis and process development, open-system thick film conductor development, wire and tape fabrication, and HTS motor design. The objective of this work is to develop high-temperature superconducting conductors (wire and tape) capable of meeting requirements for high-power electrical devices of interest to industry. The research efforts currently underway are: (1) Process development and characterization of thallium-based high-temperature superconducting closed system wire and tape, (2) Investigation of the synthesis and processing of thallium-based thick films using two-zone processing, and (3) Cryogenic design of a 30K superconducting motor. This report outlines the research that has been performed during FY96 in each of these areas

  18. Vortex pinning vs superconducting wire network: origin of periodic oscillations induced by applied magnetic fields in superconducting films with arrays of nanomagnets

    International Nuclear Information System (INIS)

    Gomez, A; Del Valle, J; Gonzalez, E M; Vicent, J L; Chiliotte, C E; Carreira, S J; Bekeris, V; Prieto, J L; Schuller, Ivan K

    2014-01-01

    Hybrid magnetic arrays embedded in superconducting films are ideal systems to study the competition between different physical (such as the coherence length) and structural length scales such as are available in artificially produced structures. This interplay leads to oscillation in many magnetically dependent superconducting properties such as the critical currents, resistivity and magnetization. These effects are generally analyzed using two distinct models based on vortex pinning or wire network. In this work, we show that for magnetic dot arrays, as opposed to antidot (i.e. holes) arrays, vortex pinning is the main mechanism for field induced oscillations in resistance R(H), critical current I c (H), magnetization M(H) and ac-susceptibility χ ac (H) in a broad temperature range. Due to the coherence length divergence at T c , a crossover to wire network behaviour is experimentally found. While pinning occurs in a wide temperature range up to T c , wire network behaviour is only present in a very narrow temperature window close to T c . In this temperature interval, contributions from both mechanisms are operational but can be experimentally distinguished. (papers)

  19. Superconductivity: materials and applications

    International Nuclear Information System (INIS)

    Duchateau, J.L.; Kircher, F.; Leveque, J.; Tixador, P.

    2008-01-01

    This digest paper presents the different types of superconducting materials: 1 - the low-TC superconductors: the multi-filament composite as elementary constituent, the world production of NbTi, the superconducting cables of the LHC collider and of the ITER tokamak; 2 - the high-TC superconductors: BiSrCaCuO (PIT 1G) ribbons and wires, deposited coatings; 3 - application to particle physics: the the LHC collider of the CERN, the LHC detectors; 4 - applications to thermonuclear fusion: Tore Supra and ITER tokamaks; 5 - NMR imaging: properties of superconducting magnets; 6 - applications in electrotechnics: cables, motors and alternators, current limiters, transformers, superconducting energy storage systems (SMES). (J.S.)

  20. Metallization of a Rashba wire by a superconducting layer in the strong-proximity regime

    Science.gov (United States)

    Reeg, Christopher; Loss, Daniel; Klinovaja, Jelena

    2018-04-01

    Semiconducting quantum wires defined within two-dimensional electron gases and strongly coupled to thin superconducting layers have been extensively explored in recent experiments as promising platforms to host Majorana bound states. We study numerically such a geometry, consisting of a quasi-one-dimensional wire coupled to a disordered three-dimensional superconducting layer. We find that, in the strong-coupling limit of a sizable proximity-induced superconducting gap, all transverse subbands of the wire are significantly shifted in energy relative to the chemical potential of the wire. For the lowest subband, this band shift is comparable in magnitude to the spacing between quantized levels that arises due to the finite thickness of the superconductor (which typically is ˜500 meV for a 10-nm-thick layer of aluminum); in higher subbands, the band shift is much larger. Additionally, we show that the width of the system, which is usually much larger than the thickness, and moderate disorder within the superconductor have almost no impact on the induced gap or band shift. We provide a detailed discussion of the ramifications of our results, arguing that a huge band shift and significant renormalization of semiconducting material parameters in the strong-coupling limit make it challenging to realize a topological phase in such a setup, as the strong coupling to the superconductor essentially metallizes the semiconductor. This metallization of the semiconductor can be tested experimentally through the measurement of the band shift.

  1. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Science.gov (United States)

    Shen, Tengming

    2016-11-15

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  2. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Tengming

    2018-01-02

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  3. Fabrication of Nb3Al superconducting wires by utilizing the mechanically alloyed Nb(Al)ss supersaturated solid-solution with low-temperature annealing

    International Nuclear Information System (INIS)

    Pan, X.F.; Yan, G.; Qi, M.; Cui, L.J.; Chen, Y.L.; Zhao, Y.; Li, C.S.; Liu, X.H.; Feng, Y.; Zhang, P.X.; Liu, H.J.

    2014-01-01

    Highlights: • This paper reported superconducting properties of the powder-in-tube Nb 3 Al wires. • The Nb 3 Al wires were made by using Nb(Al) ss supersaturated solid solution powders. • The Cu-matrix Nb 3 Al superconducting wires have been successfully fabricated. • The transport J c of Nb 3 Al wires at 4.2 K, 10 T is up to 12,700 A/cm 2 . - Abstract: High-performance Nb 3 Al superconducting wire is a promising candidate to the application of high-field magnets. However, due to the production problem of km-grade wires that are free from low magnetic field instability, the Nb 3 Al wires made by rapid heating, quenching and transformation (RHQT) are still not available to the large-scale engineering application. In this paper, we reported the properties of the in situ powder-in-tube (PIT) Nb 3 Al superconducting wires, which were made by using the mechanically alloyed Nb(Al) ss supersaturated solid solution, as well as the low temperature heat-treatment at 800 °C for 10 h. The results show that Nb 3 Al superconductors in this method possess very fine grains and well superconducting properties, though a little of Nb 2 Al and Nb impurities still keep being existence at present work. At the Nb 3 Al with a nominal 26 at.% Al content, the onset T c reaches 15.8 K. Furthermore, a series of Nb 3 Al wires and tapes with various sizes have been fabricated; for the 1.0 mm-diameter wire, the J c at 4.2 K, 10 T and 14 T have achieved 12,700 and 6900 A/cm 2 , respectively. This work suggests it is possible to develop high-performance Cu-matrix Nb 3 Al superconducting wires by directly using the Nb(Al) ss supersaturated solid-solution without the complex RHQT heat-treatment process

  4. Two-step superconducting transition in Cu-V-Si alloys

    International Nuclear Information System (INIS)

    Sharma, R.G.; Krishna, M.M.; Narlikar, A.V.

    1980-01-01

    Copper ternary alloys containing small amounts of vanadium and silicon exhibit a two-step superconducting resistive transition. The first transition occurs around 17 K, the transition temperature of β-W V 3 Si, followed by a plateau and a second transition around 10 K. The resistivity, however, does not drop to zero down to 2.5 K. Reduction of the wire diameter causes the two transitions to shift to lower temperatures. Complete superconductivity in these specimens is absent for two reasons. Firstly, the superconducting volume fraction present in these alloy-wires is below the threshold given by either the effective-medium theory or the site percolation theory. Secondly, the superconducting phase V 3 Si does not precipitate in copper matrix in a fine structure and the proximity effect does not operate strongly. Annealing causes the superconducting particles to coalesce and grow in size and suppresses the proximity effect and superconductivity further in these alloy wires. (author)

  5. Elastic stiffnesses of an Nb-Ti/Cu-composite superconductive wire

    Science.gov (United States)

    Kim, Sudook; Ledbetter, Hassel; Ogi, Hirotsugu

    2000-09-01

    Elastic-stiffness coefficients were determined on a 1.4-mm-diameter wire consisting of superconducting Nb-Ti fibers in a copper matrix, with a polyvinyl-resin coating. The matrix contained 324 Nb-Ti fibers. An electromagnetic-acoustic-resonance method was used to obtain five independent elastic-stiffness coefficients assuming transverse-isotropic symmetry. From these we calculated Young moduli, bulk modulus, and principal Poisson ratios. As a check, we used a mechanical-impulse-excitation method to directly measure the Young modulus in the fiber direction. The three-phase composite wire showed a 10% anisotropy in the Young modulus.

  6. Meissner effect in superconducting microtraps

    International Nuclear Information System (INIS)

    Cano, Daniel

    2009-01-01

    This thesis investigates the impact of the Meissner effect on magnetic microtraps for ultracold atoms near superconducting microstructures. This task has been accomplished both theoretically and experimentally. The Meissner effect distorts the magnetic fields near superconducting surfaces, thus altering the parameters of magnetic microtraps. Both computer simulations and experimental measurements demonstrate that the Meissner effect shortens the distance between the magnetic microtrap and the superconducting surface, reduces the magnetic-field gradients and dramatically lowers the trap depth. A novel numerical method for calculating magnetic fields in atom chips with superconducting microstructures has been developed. This numerical method overcomes the geometrical limitations of other calculation techniques and can solve superconducting microstructures of arbitrary geometry. The numerical method has been used to calculate the parameters of magnetic microtraps in computer-simulated chips containing thin-film wires. Simulations were carried out for both the superconducting and the normal-conducting state, and the differences between the two cases were analyzed. Computer simulations have been contrasted with experimental measurements. The experimental apparatus generates a magnetic microtrap for ultracold Rubidium atoms near a superconducting Niobium wire of circular cross section. The design and construction of the apparatus has met the challenge of integrating the techniques for producing atomic quantum gases with the techniques for cooling solid bodies to cryogenic temperatures. By monitoring the position of the atom cloud, one can observe how the Meissner effect influences the magnetic microtrap. (orig.)

  7. Meissner effect in superconducting microtraps

    Energy Technology Data Exchange (ETDEWEB)

    Cano, Daniel

    2009-04-30

    This thesis investigates the impact of the Meissner effect on magnetic microtraps for ultracold atoms near superconducting microstructures. This task has been accomplished both theoretically and experimentally. The Meissner effect distorts the magnetic fields near superconducting surfaces, thus altering the parameters of magnetic microtraps. Both computer simulations and experimental measurements demonstrate that the Meissner effect shortens the distance between the magnetic microtrap and the superconducting surface, reduces the magnetic-field gradients and dramatically lowers the trap depth. A novel numerical method for calculating magnetic fields in atom chips with superconducting microstructures has been developed. This numerical method overcomes the geometrical limitations of other calculation techniques and can solve superconducting microstructures of arbitrary geometry. The numerical method has been used to calculate the parameters of magnetic microtraps in computer-simulated chips containing thin-film wires. Simulations were carried out for both the superconducting and the normal-conducting state, and the differences between the two cases were analyzed. Computer simulations have been contrasted with experimental measurements. The experimental apparatus generates a magnetic microtrap for ultracold Rubidium atoms near a superconducting Niobium wire of circular cross section. The design and construction of the apparatus has met the challenge of integrating the techniques for producing atomic quantum gases with the techniques for cooling solid bodies to cryogenic temperatures. By monitoring the position of the atom cloud, one can observe how the Meissner effect influences the magnetic microtrap. (orig.)

  8. Analysis of Mechanical Stresses/Strains in Superconducting Wire

    Science.gov (United States)

    Barry, Matthew; Chen, Jingping; Zhai, Yuhu

    2016-10-01

    The optimization of superconducting magnet performance and development of high-field superconducting magnets will greatly impact the next generation of fusion devices. A successful magnet development, however, relies deeply on the understanding of superconducting materials. Among the numerous factors that impact a superconductor's performance, mechanical stress is the most important because of the extreme operation temperature and large electromagnetic forces. In this study, mechanical theory is used to calculate the stresses/strains in typical superconducting strands, which consist of a stabilizer, a barrier, a matrix and superconducting filaments. Both thermal loads and mechanical loads are included in the analysis to simulate operation conditions. Because this model simulates the typical architecture of major superconducting materials, such as Nb3Sn, MgB2, Bi-2212 etc., it provides a good overall picture for us to understand the behavior of these superconductors in terms of thermal and mechanical loads. This work was supported in part by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI) program.

  9. Superconducting self-correcting harmonic coils for pulsed superconducting dipole or multipole magnets

    International Nuclear Information System (INIS)

    Dael, A.; Kircher, F.; Perot, J.

    1975-01-01

    Due to the zero resistance of a superconducting wire, an induced current in a closed superconducting circuit is continuously exactly opposed to its cause. This phenomenon was applied to the correction of the field harmonics of a pulsed magnet by putting short-circuited superconducting coils of particular symmetry in the useful aperture of the magnet. After a review of the main characteristics of such devices, the construction of two correcting coils (quadrupole and sextupole) is described. Experimental results of magnetic efficiency and time behavior are given; they are quite encouraging, since the field harmonics were reduced by one or two orders of magnitude

  10. Comparison of phase boundaries between kagomé and honeycomb superconducting wire networks

    Science.gov (United States)

    Xiao, Yi; Huse, David A.; Chaikin, Paul M.; Higgins, Mark J.; Bhattacharya, Shobo; Spencer, David

    2002-06-01

    We measure resistively the mean-field superconducting-normal phase boundaries of both kagomé and honeycomb wire networks immersed in a transverse magnetic field. In addition to their agreement with theory about the overall shapes of phase diagrams, they show striking one-to-one correspondence between the cusps in the honeycomb phase boundary and those in the kagomé curve. This correspondence is due to their geometric arrangements and agrees with Lin and Nori's recent calculation. We also find that for the frustrated honeycomb network at f=1/2, the current patterns in the superconducting phase differ between the low-temperature London regime and the higher-temperature Ginzburg-Landau regime near Tc.

  11. Method for producing superconducting wire and products of the same

    International Nuclear Information System (INIS)

    Marancik, W.G.; Ormand, F.T.

    1975-01-01

    A method is described for producing a composite superconducting wire including one or more strands of high-field Type II superconductor embedded in a conductive matrix of normal material. A composite body is prepared which includes a matrix in which are embedded one or more rods of a metal which is capable of forming a high-field Type II superconductor upon high temperature extruded to an intermediate diameter, and then is hot-drawn to a final diameter at temperatures exceeding about 100 0 C, by multiple passes through drawing dies, the composite being reduced in cross-sectional area approximately 15 to 20 percent per draw. In a preferred mode of practicing the invention, the rods comprise vanadium or niobium, with the matrix being respectively gallium--bronze or tin--bronze, and the superconductive strands being formed by high temperature diffusion of the gallium or tin into the rods subsequent to drawing

  12. Josephson junctions of multiple superconducting wires

    Science.gov (United States)

    Deb, Oindrila; Sengupta, K.; Sen, Diptiman

    2018-05-01

    We study the spectrum of Andreev bound states and Josephson currents across a junction of N superconducting wires which may have s - or p -wave pairing symmetries and develop a scattering matrix based formalism which allows us to address transport across such junctions. For N ≥3 , it is well known that Berry curvature terms contribute to the Josephson currents; we chart out situations where such terms can have relatively large effects. For a system of three s -wave or three p -wave superconductors, we provide analytic expressions for the Andreev bound-state energies and study the Josephson currents in response to a constant voltage applied across one of the wires; we find that the integrated transconductance at zero temperature is quantized to integer multiples of 4 e2/h , where e is the electron charge and h =2 π ℏ is Planck's constant. For a sinusoidal current with frequency ω applied across one of the wires in the junction, we find that Shapiro plateaus appear in the time-averaged voltage across that wire for any rational fractional multiple (in contrast to only integer multiples in junctions of two wires) of 2 e /(ℏ ω ) . We also use our formalism to study junctions of two p -wave and one s -wave wires. We find that the corresponding Andreev bound-state energies depend on the spin of the Bogoliubov quasiparticles; this produces a net magnetic moment in such junctions. The time variation of these magnetic moments may be controlled by an external voltage applied across the junction. We discuss experiments which may test our theory.

  13. An investigation into preparation of silver sheathed superconducting wires with a high critical temperature

    International Nuclear Information System (INIS)

    Chaffron, Laurent

    1992-01-01

    We have shown that the critical current density of YBaCuO superconducting wires prepared using 'powder in tube' method is limited by the following principal factors: - cracks and porosity arising from the shrinkage of the powder during sintering, - irregularities in the wire section, - presence of secondary phases in the phase diagram of the three oxides, - incomplete re-oxidation at the centre of the wire, - insufficient, or complete lack of, texture in the wire, - presence of amorphous, non superconducting phase across the grains that blocks grain boundary migration. We have reduced the deleterious effects due to the first four factors by modifying prior nature of the powder, by reinforcing the sheath and by modifying the thermal treatments. We also used creep sintering to produce a strong texture; however, our study shows that texture, though necessary, is not a sufficient condition for a high current. This is because the latter is limited by the presence of the amorphous phase at too many grain boundaries. Finally, we have obtained wires in which grain boundaries are clean and which have very high critical currents by melting the wire in a thermal gradient and by passing it through the gradient very slowly. Such a technique, however, is too slow for producing superconductors. (author) [fr

  14. Graphene-based superconducting quantum point contacts

    International Nuclear Information System (INIS)

    Moghaddam, A.G.; Zareyan, M.

    2007-01-01

    We investigate the Josephson effect in the graphene nanoribbons of length L smaller than the superconducting coherence length and an arbitrary width W. We find that in contrast to an ordinary superconducting quantum point contact (SQPC), the critical supercurrent I c is not quantized for the nanoribbons with smooth and armchair edges. For a low concentration of the carriers, I c decreases monotonically with lowering W/L and tends to a constant minimum for a narrow nanoribbon with W c is zero for the smooth edges but eΔ 0 /ℎ for the armchair edges. At higher concentrations of the carriers this monotonic variation acquires a series of peaks. Further analysis of the current-phase relation and the Josephson coupling strength I c R N in terms of W/L and the concentration of carriers revels significant differences with those of an ordinary SQPC. On the other hand for a zigzag nanoribbon, we find that, similar to an ordinary SQPC, I c is quantized but to the half-integer values (n+1/2)4eΔ 0 /ℎ. (orig.)

  15. Possible high-T/sub c/ superconductivity in thin wires

    International Nuclear Information System (INIS)

    Lee, Y.C.; Mendoza, B.S.

    1989-01-01

    A heuristic approach to the theory of superconductivity based on a simple physical picture and capable of treating the simultaneous participation of multiple bosonic modes that mediate the pairing interaction is first developed. The effect of the bosonic mode damping is also accounted for. We then propose a possible mechanism of superconductivity in slender electronic systems of finite cross sections based on the pairing interaction mediated by the multiple modes of acoustic plasmons in these structures. Such modes include the quasi-one-dimensional plasmon as well as the so-called slender acoustic plasmons. The critical temperature and the energy gap/T/sub c/ ratio are then calculated by the heuristic method just developed. Numerical results on T/sub c/ in various samples are presented, showing T/sub c/ in the 150--200 K range. The ratio 2Δ 0 /T/sub c/ differs generally from the BCS value due to the temperature dependence of the mode damping. The associated coherence length is shown to be considerably smaller than the transverse dimension of the wires

  16. Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

    Science.gov (United States)

    Arnold, F.; Nyéki, J.; Saunders, J.

    2018-05-01

    In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of micro-crystalline graphite. Magnetic field dependent point-contact spectroscopy was carried out at a temperature of 1.8K using an etched aluminium tip. At zero field a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2 meV. On applying magnetic fields of up to 500mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a critical superconducting temperature of 14K.

  17. Superconductivity application technologies. Superconducting quadrupole magnet and cooling system for KEK B factory

    International Nuclear Information System (INIS)

    Tsuchiya, Kiyosumi; Yamaguchi, Kiyoshi; Sakurabata, Hiroaki; Seido, Masahiro; Matsumoto, Kozo.

    1997-01-01

    At present in National Laboratory for High Energy Physics (KEK), the construction of B factory is in progress. By colliding 8 GeV electrons and 3.5 GeV positrons, this facility generates large amounts of B mesons and anti-B mesons, and performs the elementary particle experiment of high accuracy. It is the collision type accelerator of asymmetric two-ring type comprising 8 GeV and 3.5 GeV rings. In the field of high energy physics, superconductivity technology has been put to practical use. As the objects of superconductivity technology, there are dipole magnet for bending beam, quadrupole magnet for adjusting beam, large solenoid magnet used for detector and so on. Superconducting magnets which are indispensable for high energy, superconducting wire material suitable to accelerators, and the liquid helium cooling system for maintaining superconducting magnets at 4.4 K are reported. The technologies of metallic conductors and making their coils have advanced rapidly, and also cooling technology has advanced, accordingly, superconductivity technology has reached the stage of practical use perfectly. (K.I.)

  18. Kinetics and thermodynamics of ceramic/metal interface reactions related to high T(sub c) superconducting applications

    Science.gov (United States)

    Notis, Michael R.; Oh, Min-Seok

    1990-01-01

    Superconducting ceramic materials, no matter what their form, size or shape, must eventually make contact with non-superconducting materials in order to accomplish current transfer to other parts of a real operating system, or for testing and measurement of properties. Thus, whether the configuration is a clad wire, a bulk superconducting disc, tape, or a thick or thin superconducting film on a substrate, the physical and mechanical behavior of interface (interconnections, joints, etc.) between superconductors and normal conductor materials of all kinds is of extreme importance to the technological development of these systems. Fabrication heat treatments associated with the particular joining process allow possible reactions between the superconducting ceramic and the contact to occur, and consequently influence properties at the interface region. The nature of these reactions is therefore of great broad interest, as these may be a primary determinant for the real capability of these materials. Research related both to fabrication of composite sheathed wire products, and the joining contacts for physical property measurements, as well as, a review of other related literature in the field are described. Comparison are made between 1-2-3, Bi-, and Tl-based ceramic superconductors joined to a variety of metals including Cu, Ni, Fe, Cr, Ag, Ag-Pd, Au, In, and Ga. The morphology of reaction products and the nature of interface degradation as a function of time will be highlighted.

  19. Fabrication of Nb{sub 3}Al superconducting wires by utilizing the mechanically alloyed Nb(Al){sub ss} supersaturated solid-solution with low-temperature annealing

    Energy Technology Data Exchange (ETDEWEB)

    Pan, X.F. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Yan, G., E-mail: gyan@c-nin.com [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Qi, M. [Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Cui, L.J. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Chen, Y.L.; Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity and New Energy R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Li, C.S. [Superconducting Materials Center, Northwest Institute for Nonferrous Metal Research, Xi’an 710016 (China); Liu, X.H. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Feng, Y.; Zhang, P.X. [National Engineering Laboratory for Superconducting Material, Western Superconducting Technologies (WST) Co., Ltd., Xi’an 710018 (China); Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of China), Superconductivity and New Energy R and D Center, Southwest Jiaotong University, Chengdu 610031 (China); Liu, H.J. [Institute of Plasma Physics, Chinese Academy of Sciences (CAS), Hefei 230031 (China); and others

    2014-07-15

    Highlights: • This paper reported superconducting properties of the powder-in-tube Nb{sub 3}Al wires. • The Nb{sub 3}Al wires were made by using Nb(Al){sub ss} supersaturated solid solution powders. • The Cu-matrix Nb{sub 3}Al superconducting wires have been successfully fabricated. • The transport J{sub c} of Nb{sub 3}Al wires at 4.2 K, 10 T is up to 12,700 A/cm{sup 2}. - Abstract: High-performance Nb{sub 3}Al superconducting wire is a promising candidate to the application of high-field magnets. However, due to the production problem of km-grade wires that are free from low magnetic field instability, the Nb{sub 3}Al wires made by rapid heating, quenching and transformation (RHQT) are still not available to the large-scale engineering application. In this paper, we reported the properties of the in situ powder-in-tube (PIT) Nb{sub 3}Al superconducting wires, which were made by using the mechanically alloyed Nb(Al){sub ss} supersaturated solid solution, as well as the low temperature heat-treatment at 800 °C for 10 h. The results show that Nb{sub 3}Al superconductors in this method possess very fine grains and well superconducting properties, though a little of Nb{sub 2}Al and Nb impurities still keep being existence at present work. At the Nb{sub 3}Al with a nominal 26 at.% Al content, the onset T{sub c} reaches 15.8 K. Furthermore, a series of Nb{sub 3}Al wires and tapes with various sizes have been fabricated; for the 1.0 mm-diameter wire, the J{sub c} at 4.2 K, 10 T and 14 T have achieved 12,700 and 6900 A/cm{sup 2}, respectively. This work suggests it is possible to develop high-performance Cu-matrix Nb{sub 3}Al superconducting wires by directly using the Nb(Al){sub ss} supersaturated solid-solution without the complex RHQT heat-treatment process.

  20. Point contact tunneling spectroscopy apparatus for large scale mapping of surface superconducting properties

    Energy Technology Data Exchange (ETDEWEB)

    Groll, Nickolas; Pellin, Michael J. [Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); Zasadzinksi, John F. [Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Proslier, Thomas, E-mail: prolier@anl.gov [Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States); High Energy Physics Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States)

    2015-09-15

    We describe the design and testing of a point contact tunneling spectroscopy device that can measure material surface superconducting properties (i.e., the superconducting gap Δ and the critical temperature T{sub C}) and density of states over large surface areas with size up to mm{sup 2}. The tip lateral (X,Y) motion, mounted on a (X,Y,Z) piezo-stage, was calibrated on a patterned substrate consisting of Nb lines sputtered on a gold film using both normal (Al) and superconducting (PbSn) tips at 1.5 K. The tip vertical (Z) motion control enables some adjustment of the tip-sample junction resistance that can be measured over 7 orders of magnitudes from a quasi-ohmic regime (few hundred Ω) to the tunnel regime (from tens of kΩ up to few GΩ). The low noise electronic and LabVIEW program interface are also presented. The point contact regime and the large-scale motion capabilities are of particular interest for mapping and testing the superconducting properties of macroscopic scale superconductor-based devices.

  1. Improvements in or relating to superconductive magnet coils and their formers

    International Nuclear Information System (INIS)

    McDougall, I.L.

    1977-01-01

    A method of manufacturing a superconductive magnet coil is described comprising winding on to a former a wire containing the components of a superconductive intermetallic compound and heating the assembly to a temperature such that the components of the compound react to form the intermetallic compound. The former should be made of metal, such as steel or stainless steel, of melting point higher than that at which the reaction occurs, and should have on all portions of its surface contacted by the wire a coating of a refractory material, such as Al 2 O 3 , non reactive with the metal and the wire. The wire may contain, after reaction, filaments of the intermetallic compound, and adjacent strands of wire in a single layer may be insulated one from the other by refractory material. A flange is formed on one end of the former, which may be cylindrical in shape. The refractory coating of the former may be flame sprayed into the metal. (U.K.)

  2. Probing multiband superconductivity by point-contact spectroscopy

    International Nuclear Information System (INIS)

    Daghero, D; Gonnelli, R S

    2010-01-01

    Point-contact spectroscopy was originally developed for the determination of the electron-phonon spectral function in normal metals. However, in the past 20 years it has become an important tool in the investigation of superconductors. As a matter of fact, point contacts between a normal metal and a superconductor can provide information on the amplitude and symmetry of the energy gap that, in the superconducting state, opens up at the Fermi level. In this paper we review the experimental and theoretical aspects of point-contact spectroscopy in superconductors, and we give an experimental survey of the most recent applications of this technique to anisotropic and multiband superconductors. (topical review)

  3. Exploration of new superconductors and functional materials, and fabrication of superconducting tapes and wires of iron pnictides.

    Science.gov (United States)

    Hosono, Hideo; Tanabe, Keiichi; Takayama-Muromachi, Eiji; Kageyama, Hiroshi; Yamanaka, Shoji; Kumakura, Hiroaki; Nohara, Minoru; Hiramatsu, Hidenori; Fujitsu, Satoru

    2015-06-01

    This review shows the highlights of a 4-year-long research project supported by the Japanese Government to explore new superconducting materials and relevant functional materials. The project found several tens of new superconductors by examining ∼1000 materials, each of which was chosen by Japanese experts with a background in solid state chemistry. This review summarizes the major achievements of the project in newly found superconducting materials, and the fabrication wires and tapes of iron-based superconductors; it incorporates a list of ∼700 unsuccessful materials examined for superconductivity in the project. In addition, described are new functional materials and functionalities discovered during the project.

  4. The energizing of a NMR superconducting coil by a superconducting rectifier

    International Nuclear Information System (INIS)

    Sikkenga, J.; ten Kate, H.H.J.; van der Klundert, L.J.M.; Knoben, J.; Kraaij, G.J.; Spuorenberg, C.J.G.

    1985-01-01

    NMR magnets require a good homogeneity within a certain volume and an excellent field stability. The homogeneity can be met using a superconducting shim coil system. The field stability requires a constant current, although in many cases the current decay time constant is too low, due to imperfections in the superconducting wire and joints. This can be overcome using a rectifier. The rectifier can also be used to load the coil. The combination and interaction of the superconducting NMR coil (2.0 Tesla and 0.35 m cold bore) and the rectifier (20 W / 1 kA) is tested. The safety of the system is discussed. The shim coil system can compensate the strayfield of the rectifier. The field decay compensation will be discussed

  5. Superconducting magnetic quadrupole

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  6. Superconducting Technology Program: Sandia 1993 annual report

    International Nuclear Information System (INIS)

    Roth, E.P.

    1994-05-01

    Sandia's STP program is a four-part high-temperature superconductor (HTS) research and development program consisting of efforts in powder synthesis and process development, thallium-based HTS film development, wire and tape fabrication, and HTS motor design. The objective of this work is to develop high-temperature superconducting conductors (wire and tape) capable of meeting requirements for high-power electrical devices of interest to industry. The four research efforts currently underway are: (1) process research on the material synthesis of high-temperature superconductors; (2) investigation of the synthesis and processing of thallium-based high-temperature superconducting thick films; (3) process development and characterization of high-temperature superconducting wire and tape, and (4) cryogenic design of a high-temperature superconducting motor. This report outlines the research that has been performed during FY93 in each of these four areas. A brief background of each project is included to provide historical context and perspective. Major areas of research are described, although no attempt has been made to exhaustively include all work performed in each of these areas

  7. Influence of iridium doping in MgB2 superconducting wires

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2018-01-01

    MgB2 wires with iridium doping were manufactured using the in-situ technique in a composite Cu-Nb sheath. Reaction was performed at 700°C, 800°C or 900°C for 1h in argon atmosphere. A maximum of about 1.5 at.% Ir replaces Mg in MgB2. The superconducting transition temperature is slightly lowered...... by Ir doping. The formation of IrMg3 and IrMg4 secondary phase particles is evidenced, especially for a nominal stoichiometry with 2.0 at.% Ir doping. The critical current density and accommodation field of the wires are strongly dependent on the Ir content and are generally weakened in the presence...

  8. The Quantum Socket: Wiring for Superconducting Qubits - Part 1

    Science.gov (United States)

    McConkey, T. G.; Bejanin, J. H.; Rinehart, J. R.; Bateman, J. D.; Earnest, C. T.; McRae, C. H.; Rohanizadegan, Y.; Shiri, D.; Mariantoni, M.; Penava, B.; Breul, P.; Royak, S.; Zapatka, M.; Fowler, A. G.

    Quantum systems with ten superconducting quantum bits (qubits) have been realized, making it possible to show basic quantum error correction (QEC) algorithms. However, a truly scalable architecture has not been developed yet. QEC requires a two-dimensional array of qubits, restricting any interconnection to external classical systems to the third axis. In this talk, we introduce an interconnect solution for solid-state qubits: The quantum socket. The quantum socket employs three-dimensional wires and makes it possible to connect classical electronics with quantum circuits more densely and accurately than methods based on wire bonding. The three-dimensional wires are based on spring-loaded pins engineered to insure compatibility with quantum computing applications. Extensive design work and machining was required, with focus on material quality to prevent magnetic impurities. Microwave simulations were undertaken to optimize the design, focusing on the interface between the micro-connector and an on-chip coplanar waveguide pad. Simulations revealed good performance from DC to 10 GHz and were later confirmed against experimental measurements.

  9. New Fast Response Thin Film-Based Superconducting Quench Detectors

    CERN Document Server

    Dudarev, A; van de Camp, W; Ravaioli, E; Teixeira, A; ten Kate, H H J

    2014-01-01

    Quench detection on superconducting bus bars and other devices with a low normal zone propagation velocity and low voltage build-up is quite difficult with conventional quench detection techniques. Currently, on ATLAS superconducting bus bar sections, superconducting quench detectors (SQD) are mounted to detect quench events. A first version of the SQD essentially consists of an insulated superconducting wire glued to a superconducting bus line or windings, which in the case of a quench rapidly builds up a relatively high resistance that can be easily and quietly detected. We now introduce a new generation of drastically improved SQDs. The new version makes the detection of quenches simpler, more reliable, and much faster. Instead of a superconducting wire, now a superconducting thin film is used. The layout of the sensor shows a meander like pattern that is etched out of a copper coated 25 mu m thick film of Nb-Ti glued in between layers of Kapton. Since the sensor is now much smaller and thinner, it is easi...

  10. The development of the high-tension wire for nuclear fusion superconductive magnet measurement

    International Nuclear Information System (INIS)

    Yoshida, Kiyoshi; Morita, Yohsuke; Yamazaki, Takanori; Watanabe, Kiyoshi; Furusawa, Ken-ichi.

    1987-01-01

    Following on tokamak critical plasma testing device JT-60, experimental fusion reactor JT-100 is being developed. The 6 kV high-tension wire has been developed for use in JT-100 under ultra-low temperature and high radiation environment. Used for superconductive magnet measurement, the wire is inserted in the vacuum vessel, being immersed within the liquid helium. As the insulating material of this wire, polyetherimido was found to be most suitable in the respects of radiation resistance and voltage-withstand property. In an electric wire covered with polyetherimido, which was made in trial, its test in voltage-withstand and bending characteristics at ultra-low temperature showed the wire to be usable for the intended purpose. (Mori, K.)

  11. Stable superconducting magnet. [high current levels below critical temperature

    Science.gov (United States)

    Boom, R. W. (Inventor)

    1967-01-01

    Operation of a superconducting magnet is considered. A method is described for; (1) obtaining a relatively high current in a superconducting magnet positioned in a bath of a gas refrigerant; (2) operating a superconducting magnet at a relatively high current level without training; and (3) operating a superconducting magnet containing a plurality of turns of a niobium zirconium wire at a relatively high current level without training.

  12. Probing Andreev bound states in one-atom superconducting contacts

    Energy Technology Data Exchange (ETDEWEB)

    Pothier, Hugues; Janvier, Camille; Tosi, Leandro; Girit, Caglar; Goffman, Marcelo; Esteve, Daniel; Urbina, Cristian [Quantronics Group, SPEC, CEA-Saclay (France)

    2015-07-01

    Superconductors are characterized by a dissipationless current. Since the work of Josephson 50 years ago, it is known that a supercurrent can even flow through tunnel junctions between superconductors. This Josephson effect also occurs through any type of ''weak links'' between superconductors: non-superconducting materials, constrictions,.. A unified understanding of the Josephson effect has emerged from a mesoscopic description of weak links. It relies on the existence of doublets of localized states that have energies below the superconducting gap: the Andreev bound states. I will present experiments performed on the simplest conductor possible, a single-atom contact between superconductors, that illustrate these concepts. The most recent work demonstrates time-domain manipulation of quantum superpositions of Andreev bound states.

  13. Search for Superconducting Energy Gap in UPt3 by Point-Contact Spectroscopy

    International Nuclear Information System (INIS)

    Gouchi, Jun; Sumiyama, Akihiko; Yamaguchi, Akira; Motoyama, Gaku; Kimura, Noriaki; Yamamoto, Etsuji; Haga, Yoshinori; Ōnuki, Yoshichika

    2015-01-01

    We have investigated the differential resistance of the point contacts between heavy-fermion superconductor UPt 3 and a normal metal Pt, which were fabricated using a commercial piezo-electric actuator, and retried the observation of the energy gap of UPt 3 . A V-shaped dip is observed in both normal and superconducting states and disappeared around T K ∼ 20 K, suggesting that it is related to the Kondo effect. Below the superconducting transition temperature, a shallow double-minimum structure, which indicates the energy gap, has been observed for the contacts on the faces perpendicular to the a-, b- and c-axes of UPt 3

  14. Characterisation of superconducting capillaries for magnetic shielding of twisted-wire pairs in a neutron electric dipole moment experiment

    Energy Technology Data Exchange (ETDEWEB)

    Henry, S., E-mail: s.henry@physics.ox.ac.uk; Pipe, M.; Cottle, A.; Clarke, C.; Divakar, U.; Lynch, A.

    2014-11-01

    The cryoEDM neutron electric dipole moment experiment requires a SQUID magnetometry system with pick-up loops inside a magnetically shielded volume connected to SQUID sensors by long (up to 2 m) twisted-wire pairs (TWPs). These wires run outside the main shield, and therefore must run through superconducting capillaries to screen unwanted magnetic pick-up. We show that the average measured transverse magnetic pick-up of a set of lengths of TWPs is equivalent to a loop area of 5.0×10{sup −6} m{sup 2}/m, or 14 twists per metre. From this we set the requirement that the magnetic shielding factor of the superconducting capillaries used in the cryoEDM system must be greater than 8.0×10{sup 4}. The shielding factor—the ratio of the signal picked-up by an unshielded TWP to that induced in a shielded TWP—was measured for a selection of superconducting capillaries made from solder wire. We conclude the transverse shielding factor of a uniform capillary is greater than 10{sup 7}. The measured pick-up was equal to, or less than that due to direct coupling to the SQUID sensor (measured without any TWP attached). We show that discontinuities in the capillaries substantially impair the magnetic shielding, yet if suitably repaired, this can be restored to the shielding factor of an unbroken capillary. We have constructed shielding assemblies for cryoEDM made from lengths of single core and triple core solder capillaries, joined by a shielded Pb cylinder, incorporating a heater to heat the wires above the superconducting transition as required.

  15. Superconducting Magnet Power Supply and Hard-Wired Quench Protection at Jefferson Lab for 12 GeV Upgrade

    International Nuclear Information System (INIS)

    Ghoshal, Probir K.; Bachimanchi, Ramakrishna; Fair, Ruben J.; Gelhaar, David; Kumar, Onish

    2017-01-01

    The superconducting magnet system in Hall B being designed and built as part of the Jefferson Lab 12 GeV upgrade requires powering two conduction cooled superconducting magnets - a torus and a solenoid. The torus magnet is designed to operate at 3770 A and solenoid at 2416 A. Failure Modes and Effects Analysis (FMEA) determined that voltage level thresholds and dump switch operation for magnet protection should be tested and analyzed before incorporation into the system. The designs of the quench protection and voltage tap sub-systems were driven by the requirement to use a primary hard-wired quench detection sub-system together with a secondary PLC-based protection. Parallel path voltage taps feed both the primary and secondary quench protection sub-systems. The PLC based secondary protection is deployed as a backup for the hard-wired quench detection sub-system and also acts directly on the dump switch. Here, we describe a series of tests and modifications carried out on the magnet power supply and quench protection system to ensure that the superconducting magnet is protected for all fault scenarios.

  16. A New Understanding of the Heat Treatment of Nb-Sn Superconducting Wires

    Science.gov (United States)

    Sanabria, Charlie

    Enhancing the beam energy of particle accelerators like the Large Hadron Collider (LHC), at CERN, can increase our probability of finding new fundamental particles of matter beyond those predicted by the standard model. Such discoveries could improve our understanding of the birth of universe, the universe itself, and/or many other mysteries of matter--that have been unresolved for decades--such as dark matter and dark energy. This is obviously a very exciting field of research, and therefore a worldwide collaboration (of universities, laboratories, and the industry) is attempting to increase the beam energy in the LHC. One of the most challenging requirements for an energy increase is the production of a magnetic field homogeneous enough and strong enough to bend the high energy particle beam to keep it inside the accelerating ring. In the current LHC design, these beam bending magnets are made of Nb Ti superconductors, reaching peak fields of 8 T. However, in order to move to higher fields, future magnets will have to use different and more advanced superconducting materials. Among the most viable superconductor wire technologies for future particle accelerator magnets is Nb3Sn, a technology that has been used in high field magnets for many decades. However, Nb3Sn magnet fabrication has an important challenge: the fact the wire fabrication and the coil assembly itself must be done using ductile metallic components (Nb, Sn, and Cu) before the superconducting compound (Nb3 Sn) is activated inside the wires through a heat treatment. The studies presented in this thesis work have found that the heat treatment schedule used on the most advanced Nb3Sn wire technology (the Restacked Rod Process wires, RRPRTM) can still undergo significant improvements. These improvements have already led to an increase of the figure of merit of these wires (critical current density) by 28%.

  17. Application of superconductivity to pulse fields

    International Nuclear Information System (INIS)

    Saito, Shigeo; Suzawa, Chizuru; Ohkura, Kengo; Nagata, Masayuki; Kawashima, Masao

    1984-01-01

    Numerous attempts to apply the superconductive phenomena of zero electrical resistivity to AC (pulsed) magnets in addition to conventional DC magnet fields are being made in the areas of poloidal coils of nuclear fusion, energy storage, rotary machines, and induction for stabilization of electric power systems. In pulsed superconductive magnets, the stability of the superconductivity and the generation of heat due to AC loss are serious problems. Based on the knowledge obtained through the development of various types of superconductors, magnets, cryostats, and other superconductive-related products, Cu-Ni/Cu/Nb-Ti mixed-matrix fine multifilamentary superconductor wire and the stable, low AC loss superconductors used therein, magnets, and FRP cryostats are developed and manufactured. (author)

  18. Superconducting coil development and motor demonstration: Overview

    Science.gov (United States)

    Gubser, D. U.

    1995-12-01

    Superconducting bismuth-cuprate wires, coils, and magnets are being produced by industry as part of a program to test the viability of using such magnets in Naval systems. Tests of prototype magnets, coils, and wires reveal progress in commercially produced products. The larger magnets will be installed in an existing superconducting homopolar motor and operated initially at 4.2K to test the performance. It is anticipated that approximately 400 Hp will be achieved by the motor. This article reports on the initial tests of the magnets, coils, and wires as well as the development program to improve their performance.

  19. Superconductivity in Spain. Midas program

    International Nuclear Information System (INIS)

    Yndurain, F.

    1996-01-01

    The different activities in the field of applied superconductivity carried out in Spain under the auspices of the MIDAS program are reported. Applications using both low- and high-temperature superconductors are considered. In the low temperature superconductors case, the design and construction of a 1 mega joule SMES (Superconducting Magnetic Energy Storage) unit, as well as the fabrication of voltage and resistance standards, are reviewed. Developments involving the design and fabrication of an inductive current fault limited and mono- and multi-filamentary wires and tapes using high-temperature superconductors are discussed. Finally, the prospects for the application of superconductivity technology to electric power systems for the electric utilities is considered. (author)

  20. Improved thermal isolation for superconducting magnet systems

    Science.gov (United States)

    Wiebe, E. R.

    1974-01-01

    Closed-cycle refrigerating system for superconductive magnet and maser is operated in vacuum environment. Each wire leading from external power source passes through cooling station which blocks heat conduction. In connection with these stations, switch with small incandescent light bulb, which generates heat, is used to stop superconduction.

  1. Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Paul (ed.) [Jena Univ. (Germany). Inst. fuer Festkoerperphysik, AG Tieftemperaturphysik

    2015-07-01

    The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

  2. Applied superconductivity. Handbook on devices and applications. Vol. 1 and 2

    International Nuclear Information System (INIS)

    Seidel, Paul

    2015-01-01

    The both volumes contain the following 12 chapters: 1. Fundamentals; 2. Superconducting Materials; 3. Technology, Preparation, and Characterization (bulk materials, thin films, multilayers, wires, tapes; cooling); 4, Superconducting Magnets; 5. Power Applications (superconducting cables, superconducting current leads, fault current limiters, transformers, SMES and flywheels; rotating machines; SmartGrids); 6. Superconductive Passive Devices (superconducting microwave components; cavities for accelerators; superconducting pickup coils; magnetic shields); 7. Applications in Quantum Metrology (superconducting hot electron bolometers; transition edge sensors; SIS Mixers; superconducting photon detectors; applications at Terahertz frequency; detector readout); 8. Superconducting Radiation and Particle Detectors; 9. Superconducting Quantum Interference (SQUIDs); 10. Superconductor Digital Electronics; 11. Other Applications (Josephson arrays as radiation sources. Tunable microwave devices) and 12. Summary and Outlook (of the superconducting devices).

  3. New technique for wiring SSC superconducting sextupole corrector coils

    International Nuclear Information System (INIS)

    Leon, B.

    1985-01-01

    There exists in the electronics industry, a technology for the manufacture of printed circuit (PC) boards which is directly transferable into the creation of highly controlled coils, such as the SSC sextupole superconducting corrector coils. This technology, which uses a process of laying down insulated wire in highly controlled patterns has heretofore been confined exclusively to the manufacture of high density printed circuit (PC) boards, possibly due to an ignorance of its utility in the field of precision winding of coils. This ability to fix wires in a well defined location can be used to produce precision wound coils in a very cost-effective manner. These coils may be superior in quality to conventionally made coils. Before describing what can be created with this technology, it is necessary to take a look at this coil winding process, the MULTIWIRE process, and the industry which has utilized this technology

  4. A-15 superconducting composite wires and a method for making

    International Nuclear Information System (INIS)

    Suenaga, M.; Klamut, C. J.; Luhman, Th. S.

    1984-01-01

    A method for fabricating superconducting wires wherein a billet of copper containing filaments of niobium or vanadium is rolled to form a strip which is wrapped about a tin-alloy core to form a composite. The alloy is a tin-copper alloy for niobium filaments and a gallium-copper alloy for vanadium filaments. The composite is then drawn down to a desired wire size and heat treated. During the heat treatment process, The tin in the bronze reacts with the niobium to form the superconductor niobium tin. In the case where vanadium is used, the gallium in the gallium bronze reacts with the vanadium to form the superconductor vanadium gallium. This new process eliminates the costly annealing steps, external tin plating and drilling of bronze ingots required in a number of prior art processes

  5. Superconducting magnet applications in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Berglund, P; Collan, H K; Lounasmaa, O V

    1983-01-01

    A short review of superconducting magnet applications in Finland is presented. The development work was done in areas that seem to offer potential for a significant break-through technology. So far our efforts have covered magnetic separation, electric DC machinery and medical NMR imaging, and it is now being extended to biological NMR on living tissue and to particle physics experiments. Our work has been facilitated by the recently started fabrication of domestic superconducting wire.

  6. Superconducting Generators for Airborne Applications and YBCO-Coated Conductors (Preprint)

    National Research Council Canada - National Science Library

    Barnes, Paul N; Levin, George A; Durkin, Edward B

    2008-01-01

    .... Superconducting generators can address this need. Recently, several successful rotating machinery projects demonstrated the practicality and feasibility of the technology using the high temperature superconducting BSCCO wire...

  7. Development of prototype DC superconducting cable for railway system

    International Nuclear Information System (INIS)

    Tomita, Masaru; Fukumoto, Yusuke; Suzuki, Kenji; Miryala, Muralidhar

    2010-01-01

    High Temperature Superconducting (HTSC) wire has significant potential for railway system applications. HTSC wire is currently a promising candidate for various engineering applications such as transformers and motors for railway system. HTSC direct current (DC) cable is ideal for a feeder of the overhead contact line system between the substation and the electric train. We completed a prototype Bi-2223 tape based direct current cable for trial purposes of several meters length. In the energizing experiment the current of 1720 A successfully constantly flew.

  8. Superconductivity

    International Nuclear Information System (INIS)

    Palmieri, V.

    1990-01-01

    This paper reports on superconductivity the absence of electrical resistance has always fascinated the mind of researchers with a promise of applications unachievable by conventional technologies. Since its discovery superconductivity has been posing many questions and challenges to solid state physics, quantum mechanics, chemistry and material science. Simulations arrived to superconductivity from particle physics, astrophysic, electronics, electrical engineering and so on. In seventy-five years the original promises of superconductivity were going to become reality: a microscopical theory gave to superconductivity the cloth of the science and the level of technological advances was getting higher and higher. High field superconducting magnets became commercially available, superconducting electronic devices were invented, high field accelerating gradients were obtained in superconductive cavities and superconducting particle detectors were under study. Other improvements came in a quiet progression when a tornado brought a revolution in the field: new materials had been discovered and superconductivity, from being a phenomenon relegated to the liquid Helium temperatures, became achievable over the liquid Nitrogen temperature. All the physics and the technological implications under superconductivity have to be considered ab initio

  9. Apparent destruction of superconductivity in the disordered one-dimensional limit

    International Nuclear Information System (INIS)

    Graybeal, J.M.; Mankiewich, P.M.; Dynes, R.C.; Beasley, M.R.

    1987-01-01

    We present the results of a model-system study of the competition between superconductivity and disorder in narrow superconducting wires. As one moves from the two-dimensional regime toward the one-dimensional limit, large and systematic reductions in the superconducting transition temperature are obtained. The observed behavior extrapolates to the total destruction of superconductivity in the disordered one-dimensional limit. Our findings are in clear disagreement with a recent theoretical treatment. In addition, the superconducting fluctuations appear to be modified by disorder for the narrowest samples

  10. Rapid characterization of superconducting wires and tapes in strong pulsed magnetic fields

    International Nuclear Information System (INIS)

    Bockstal, L. van; Keyser, A. de; Deschagt, J.; Hopkins, S.C.; Glowacki, B.A.

    2007-01-01

    A new measurement system for rapid characterization of superconducting wires and tapes is developed. The CryoPulse-BI is a system to provide a direct measurement of critical material parameters for superconducting materials when high long pulsed magnetic fields and strong currents are applied. In the experiments, synchronized magnetic fields up to 30 T and current pulses up to 5 kA are generated with adjustable timing. Varying the magnetic field strength, the current through the sample and the BI timing allows for a thorough characterization of the sample and the determination of critical currents. The rapid cycle time of the experiments yields a rapid and thorough determination of the critical parameters. The method has been tested on low T c as well as high T c materials with the field parallel or perpendicular to the current. The discussion covers the current state of the art including a comparison of our results to classical DC characterization measurements

  11. Fabrication of Chemically Doped, High Upper Critical Field Magnesium Diboride Superconducting Wires

    Energy Technology Data Exchange (ETDEWEB)

    Marzik, James, V.

    2005-10-13

    Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve its superconducting properties to the levels required for high field magnets, but the doping is difficult to accomplish through the usual route of solid state reaction and diffusion. Further, superconducting cables of MgB2 are difficult to fabricate because of the friable nature of the material. In this Phase I STTR project, doped and undoped boron fibers were made by chemical vapor deposition (CVD). Several >100m long batches of doped and undoped fiber were made by CVD codeposition of boron plus dopants. Bundles of these fibers infiltrated with liquid magnesium and subsequently converted to MgB2 to form Mg-MgB2 metal matrix composites. In a parallel path, doped boron nano-sized powder was produced by a plasma synthesis technique, reacted with magnesium to produce doped MgB2 superconducting ceramic bodies. The doped powder was also fabricated into superconducting wires several meters long. The doped boron fibers and powders made in this program were fabricated into fiber-metal composites and powder-metal composites by a liquid metal infiltration technique. The kinetics of the reaction between boron fiber and magnesium metal was investigated in fiber-metal composites. It was found that the presence of dopants had significantly slowed the reaction between magnesium and boron. The superconducting properties were measured for MgB2 fibers and MgB2 powders made by liquid metal infiltration. Properties of MgB2 products (Jc, Hc2) from Phase I are among the highest reported to date for MgB2 bulk superconductors. Chemically doped MgB2 superconducting magnets can perform at least as well as NbTi and NbSn3 in high magnetic fields and still offer an improvement over the latter two in terms of operating temperature. These characteristics make doped MgB2 an effective material for high magnetic field applications, such as magnetic confined fusion, and medical MRI devices. Developing

  12. Fabrication of Chemically Doped, High Upper Critical Field Magnesium Diboride Superconducting Wires

    International Nuclear Information System (INIS)

    Marzik, James V.

    2005-01-01

    Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve its superconducting properties to the levels required for high field magnets, but the doping is difficult to accomplish through the usual route of solid state reaction and diffusion. Further, superconducting cables of MgB2 are difficult to fabricate because of the friable nature of the material. In this Phase I STTR project, doped and undoped boron fibers were made by chemical vapor deposition (CVD). Several >100m long batches of doped and undoped fiber were made by CVD codeposition of boron plus dopants. Bundles of these fibers infiltrated with liquid magnesium and subsequently converted to MgB2 to form Mg-MgB2 metal matrix composites. In a parallel path, doped boron nano-sized powder was produced by a plasma synthesis technique, reacted with magnesium to produce doped MgB2 superconducting ceramic bodies. The doped powder was also fabricated into superconducting wires several meters long. The doped boron fibers and powders made in this program were fabricated into fiber-metal composites and powder-metal composites by a liquid metal infiltration technique. The kinetics of the reaction between boron fiber and magnesium metal was investigated in fiber-metal composites. It was found that the presence of dopants had significantly slowed the reaction between magnesium and boron. The superconducting properties were measured for MgB2 fibers and MgB2 powders made by liquid metal infiltration. Properties of MgB2 products (Jc, Hc2) from Phase I are among the highest reported to date for MgB2 bulk superconductors. Chemically doped MgB2 superconducting magnets can perform at least as well as NbTi and NbSn3 in high magnetic fields and still offer an improvement over the latter two in terms of operating temperature. These characteristics make doped MgB2 an effective material for high magnetic field applications, such as magnetic confined fusion, and medical MRI devices. Developing

  13. Stress relaxation technique of high magnetic field superconducting magnet for the nuclear fusion

    International Nuclear Information System (INIS)

    Kamimoto, Masayuki; Tateishi, Hiroshi; Agatsuma, Ko; Arai, Kazuaki; Umeda, Masaichi

    1999-01-01

    Here were attempted not only to prove effectiveness of a stress self-supporting type wire material for magnet constituting technique, but also to develop a fiber reinforcing type superconducting wire material used by materials with excellent strain resistance to expand usable range of the stress self-supporting type with material. In 1997 fiscal year, superconductive features of the wire material produced by using composite processing method were evaluated, actual applicability for superconducting wire material was inspected, and investigation on manufacturing parameter of NbN thin films on trial production at present apparatus was conducted. (G.K.)

  14. A high Tc superconducting liquid nitrogen level sensor

    International Nuclear Information System (INIS)

    Jin, J. X.; Liu, H. K.; Dou, S. X.; Grantham, C.; Beer, J.

    1996-01-01

    Full text: The dramatic resistance change in the superconducting-normal transition temperature range enables a high T c superconductor to be considered for designing a liquid nitrogen level sensor. A (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+x Ag clad superconducting wire is selected and tested as a continuous liquid nitrogen level sensor to investigate the possibility for this application. The (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10+x Ag clad superconducting wire has approximately 110 K critical temperature, with more flexible and stable properties compared with bulk shape ceramic high T c superconductors. The voltage drops across the sensor are tested with different immersion lengths in liquid nitrogen. The accuracy of the HTS sensor is analysed with its dR/dT in the superconducting-normal transition range. The voltage signal is sensitive to liquid nitrogen level change, and this signal can be optimized by controlling the transport current. The problems of the Ag clad superconductor are that the Ag sheath thermal conductivity is very high, and the sensor normal resistance is low. These are the main disadvantages for using such a wire as a continuous level sensor. However, a satisfactory accuracy can be achieved by control of the transport current. A different configuration of the wire sensor is also designed to avoid this thermal influence

  15. Energy losses in mixed matrix superconducting wires under fast pulsed conditions

    International Nuclear Information System (INIS)

    Wollan, J.J.

    1976-01-01

    Energy losses have been measured on a set of mixed matrix (CuNi, Cu, NbTi) superconducting wires at B's up to 1.5 x 10 7 G/s. The losses have been measured as a function of wire diameter, twist pitch, maximum applied field, and B. Both static and dynamic losses were measured for a field applied perpendicularly to the wire axis. The dynamic losses were measured by slowly applying an external field to a sample and then causing the field to decay exponentially in roughly 1 ms to 10 ms. Under low B (9 kG) and B (10 6 G/s) conditions the hysteretic loss dominated. At high B (21 kG) and B (1.5 x 10 7 G/s) the matrix losses became dominant. The systematic variation of the losses with the mentioned parameters will be presented and will be compared to theoretical predictions

  16. Effects of drawing and high-pressure sintering on the superconducting properties of (Ba,K)Fe2As2 powder-in-tube wires

    International Nuclear Information System (INIS)

    Pyon, Sunseng; Yamasaki, Yuji; Tamegai, Tsuyoshi; Kajitani, Hideki; Koizumi, Norikiyo; Tsuchiya, Yuji; Awaji, Satoshi; Watanabe, Kazuo

    2015-01-01

    The evolution of the superconducting properties of round wires of (Ba,K)Fe 2 As 2 fabricated by the powder-in-tube (PIT) method is systematically studied. After establishing the method to obtain the largest transport critical current density (J c ) in round wires using the hot isostatic press technique, we investigated how the transition temperature (T c ), J c , and microstructures change at each step of the wire fabrication. Unexpectedly, we find that superconducting properties of the wire core are significantly damaged by the drawing process. Systematic measurements of J c and T c of the core superconductor after each drawing and sintering process clarified the evolution of degradation by the drawing process and recovery by heat treatment. (paper)

  17. Development of 50 MVA superconducting generator

    International Nuclear Information System (INIS)

    Ueda, Kiyotaka; Maki, Naoki; Takahashi, Noriyoshi; Ogata, Hisanao; Sanematsu, Toshihiro.

    1984-01-01

    Superconducting synchronous generators are expected to be the large capacity turbogenerators of next generation, but they have the structural features considerably different from conventional generators, such as low temperature multiple cylinder rotors and air gap armature winding. For the purpose of grasping the performance of superconducting generators and establishing the fundamental technology for their practical use, Hitachi Ltd. manufactured a 50 MVA superconducting generator. As the results of test, the precooling operation was smoothly finished for about 40 hours, and the superconducting rotor rotated stably at 3000 rpm. The steady and transient electrical characteristics were able to be grasped. It is intended to reflect these results to the development of a practical generator of 500 MVA class expected as the next step. When the superconducting exciting winding cooled by liquid helium is used, the reduction of weight, the improvement of efficiency and the improvement of the stability of power system can be expected. The structural features and the function of superconducting generators, the present state of the development in the world, the outline of the 50 MVA generator, the test results and the problems and the prospect hereafter are reported. The superconducting winding was made of NbTiZr alloy multicore wires. (Kako, I.)

  18. Superconductivity

    CERN Document Server

    Thomas, D B

    1974-01-01

    A short general review is presented of the progress made in applied superconductivity as a result of work performed in connection with the high-energy physics program in Europe. The phenomenon of superconductivity and properties of superconductors of Types I and II are outlined. The main body of the paper deals with the development of niobium-titanium superconducting magnets and of radio-frequency superconducting cavities and accelerating structures. Examples of applications in and for high-energy physics experiments are given, including the large superconducting magnet for the Big European Bubble Chamber, prototype synchrotron magnets for the Super Proton Synchrotron, superconducting d.c. beam line magnets, and superconducting RF cavities for use in various laboratories. (0 refs).

  19. Melt formed superconducting joint between superconducting tapes

    International Nuclear Information System (INIS)

    Benz, M.G.; Knudsen, B.A.; Rumaner, L.E.; Zaabala, R.J.

    1992-01-01

    This patent describes a superconducting joint between contiguous superconducting tapes having an inner laminate comprised of a parent-metal layer selected from the group niobium, tantalum, technetium, and vanadium, a superconductive intermetallic compound layer on the parent-metal layer, a reactive-metal layer that is capable of combining with the parent-metal and forming the superconductive intermetallic compound, the joint comprising: a continuous precipitate of the superconductive intermetallic compound fused to the tapes forming a continuous superconducting path between the tapes

  20. Capacitor energy needed to induce transitions from the superconducting to the normal state

    International Nuclear Information System (INIS)

    Eberhard, P.H.; Ross, R.R.

    1985-08-01

    The purpose of this paper is to describe a technique to turn a long length of superconducting wire normal by dumping a charged capacitor into it and justify some formulae needed in the design. The physical phenomenon is described. A formula for the energy to be stored in the capacitor is given. There are circumstances where the dc in an electrical circuit containing superconducting elements has to be turned off quickly and where the most convenient way to switch the current off is to turn a large portion or all of the superconducting wire normal. Such was the case of the Time Projection Chamber (TPC) superconducting magnet as soon as a quench was detected. The technique used was the discharge of a capacitor into the coil center tap. It turned the magnet winding normal in ten milliseconds or so and provided an adequate quench protection. The technique of discharging a capacitor into a superconducting wire should have many other applications whenever a substantial resistance in a superconducting circuit has to be generated in that kind of time scale. The process involves generating a pulse of large currents in some part of the circuit and heating the wire up by ac losses until the value of the wire critical current is smaller than the dc current. Use of low inductance connections to the circuit is necessary. Then the dc gets turned off due to the resistance of the wire as in a magnet quench

  1. Universal transport characteristics of multiple topological superconducting wires with large charging energy

    Energy Technology Data Exchange (ETDEWEB)

    Kashuba, Oleksiy; Trauzettel, Bjoern [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Timm, Carsten [Institut fuer Theoretische Physik, TU Dresden, 01062 Dresden (Germany)

    2016-07-01

    The system with multiple Majorana states coupled to the normal lead can potentially support the interaction between Majorana fermions and electrons. Such system can be implemented by several floating topological superconducting wires with large charging energy asymmetrically coupled to two normal leads. The analysis of the renormalization flow shows that there is a single fixed point - the strong coupling limit of isotropic antiferromagnetic Kondo model. The topological Kondo-like interaction leads also to the selective renormalization of the tunneling coefficients, strongly enhancing one component and suppressing others. Thus, charging energy crucially changes the transport properties of the system leading to the universal single-channel conductance independently from the values of the initial leads-wires coupling.

  2. Magnetic and superconducting nanowires

    DEFF Research Database (Denmark)

    Piraux, L.; Encinas, A.; Vila, L.

    2005-01-01

    magnetic and superconducting nanowires. Using different approaches entailing measurements on both single wires and arrays, numerous interesting physical properties have been identified in relation to the nanoscopic dimensions of these materials. Finally, various novel applications of the nanowires are also...

  3. An internal superconducting ''holding-coil'' for frozen spin targets

    International Nuclear Information System (INIS)

    Dutz, H.; Gehring, R.; Goertz, S.; Kraemer, D.; Meyer, W.; Reicherz, G.; Thomas, A.

    1995-01-01

    A new concept of a small superconducting holding magnet, placed inside a polarizing refrigerator, has been developed for frozen spin targets. The superconducting wire has been wound on the inner cooling shield of the vertical dilution refrigerator of the Bonn frozen spin target. The maximum field of the magnet is 0.35 T. The total thickness of the superconducting coil consisting of the wire and the copper carrier is of the order of 500 μm. Based on this concept, a frozen spin target is under construction for the measurement of the Gerasimov-Drell-Hearn sum rule with polarized real photons at the Mainz microtron MAMI and the Bonn electron stretcher accelerator ELSA. ((orig.))

  4. An internal superconducting ``holding-coil`` for frozen spin targets

    Energy Technology Data Exchange (ETDEWEB)

    Dutz, H. [Bonn Univ. (Germany). Physikalisches Inst.; Gehring, R. [Bonn Univ. (Germany). Physikalisches Inst.; Goertz, S. [Bonn Univ. (Germany). Physikalisches Inst.; Kraemer, D. [Bonn Univ. (Germany). Physikalisches Inst.; Meyer, W. [Bonn Univ. (Germany). Physikalisches Inst.; Reicherz, G. [Bonn Univ. (Germany). Physikalisches Inst.; Thomas, A. [Bonn Univ. (Germany). Physikalisches Inst.

    1995-03-01

    A new concept of a small superconducting holding magnet, placed inside a polarizing refrigerator, has been developed for frozen spin targets. The superconducting wire has been wound on the inner cooling shield of the vertical dilution refrigerator of the Bonn frozen spin target. The maximum field of the magnet is 0.35 T. The total thickness of the superconducting coil consisting of the wire and the copper carrier is of the order of 500 {mu}m. Based on this concept, a frozen spin target is under construction for the measurement of the Gerasimov-Drell-Hearn sum rule with polarized real photons at the Mainz microtron MAMI and the Bonn electron stretcher accelerator ELSA. ((orig.))

  5. Proposal for the change of contractor for the supply of superconducting wires for the LHC corrector magnets

    CERN Document Server

    2001-01-01

    This document concerns the change of contractor for the supply of superconducting wires of four different types (1 to 4) for the LHC corrector magnets. For the reasons set out in this document, the Finance Committee is invited to agree to the negotiation of a contract with ALSTOM (FR), for the supply of superconducting wire for a total amount of 1 963 793 euros (3 140 059 Swiss francs), not subject to revision until 31 December 2001, with options for up to 20% additional wire, for an additional amount of 392 759 euros (628 012 Swiss francs), not subject to revision until 31 December 2001, bringing the total amount to 2 356 552 euros (3 768 071 Swiss francs), not subject to revision until 31 December 2001. The rate of exchange which has been used is that stipulated in the tender. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: FR - 67%, US - 27%, DE - 4% and BE - 2%.

  6. Properties of a tunnel point contact between aluminum and the superconducting amorphous alloy NiZr2

    International Nuclear Information System (INIS)

    Gantmakher, V.F.; Golubov, A.A.; Osherov, M.V.

    1989-01-01

    The I-V characteristics of a tunnel point contact between aluminum and an amorphous ribbon resembling NiZr 2 in composition differ qualitatively from those of ordinary tunnel junctions between a superconductor and a normal metal. It is demonstrated that the observed curve shapes cannot be explained by accounting solely for one-particle tunneling in conditions of the proximity effect. This is followed by a qualitative discussion of a model in which the current rise at the potential eV equal to the gap width Δ (T) is generated by two-particle electron tunneling through the intermediate state which is manifested as a Cooper pair on the Fermi-level in the thin superconducting layer produced in the aluminum by the proximity effect. The current flowing through the contact will cause a breakdown of superconductivity in the vicinity of the contact at voltages exceeding the gap width. Smallness of the junction plays a decisive role both in inducing superconductivity for eV Δ

  7. Upper critical fields in multifilamentary NbTi alloy superconducting wires

    International Nuclear Information System (INIS)

    Watanabe, Kazuo; Muto, Yoshio; Noto, Koshichi.

    1991-01-01

    In order to improve the high field performance of superconducting magnets, the upper critical field B c2 for practical multifilamentary alloy wires of NbTi, NbTiTa and NbTiHf were examined in respect with the usage of a pressurized superfluid cooling technique. The addition of Ta or Hf to NbTi enhanced by 0.5 T for B c2 at 1.8 K. Although the addition of a heavy element such as Ta or Hf has been regarded as suppressing Pauli-paramagnetism so far, it was found that the mechanism for B c2 enhancement by Hf addition is different from that by Ta addition. (author)

  8. A new technique for wiring SSC superconducting sextupole corrector coils

    International Nuclear Information System (INIS)

    Leon, B.

    1985-01-01

    There exists in the electronics industry, a technology for the manufacture of printed circuit (PC) boards which is directly transferable into the creation of highly controlled coils, such as the SSC sextupole superconducting corrector coils. This technology, which uses a process of laying down insulated wire in highly controlled patterns, has heretofore been confined excusively to the manufacture of high density printed circuit (PC) boards, possibly due to an ignorance of its utility in the field of precision winding of coils. This ability to fix wires in a well defined location can be used to produce precision wound coils in a very cost-effective manner. These coils may be superior in quality to conventionally made coils. Before describing what can be created with this technology, it is necessary to take a look at this coil winding process, the MULTIWIRE process, and the industry which has utilized this technology

  9. Proposal to negotiate an amendment to an existing contract for the supply of superconducting wire for the LHC corrector magnets

    CERN Document Server

    2005-01-01

    This document concerns the proposal to negotiate an amendment to an existing contract for the supply of superconducting wire for the LHC corrector magnets. For the reasons explained in this document, the Finance Committee is invited to approve an amendment to an existing contract with the firm ALSTOM (FR) for the supply of an additional 1 270 km of superconducting wire (Types 1 and 2) for an amount of 257 549 euros (402 679 Swiss francs), subject to revision for inflation, bringing the total to a maximum amount of 2 814 170 euros (4 399 955 Swiss francs), subject to revision for inflation. The amounts in Swiss francs have been calculated using the present rate of exchange.

  10. Superconducting power distribution structure for integrated circuits

    International Nuclear Information System (INIS)

    Ruby, R.C.

    1991-01-01

    This patent describes a superconducting power distribution structure for an integrated circuit. It comprises a first superconducting capacitor plate; a second superconducting capacitor plate provided with electrical isolation means within the second capacitor plate; dielectric means separating the first capacitor plate from the second capacitor plate; first via means coupled at a first end to the first capacitor plate and extending through the dielectric and the electrical isolation means of the second capacitor plate; first contact means coupled to a second end of the first via means; and second contact means coupled to the second capacitor plate such that the first contact means and the second contact means are accessible from the same side of the second capacitor plate

  11. Superconductivity

    CERN Document Server

    Poole, Charles P; Farach, Horacio A

    1995-01-01

    Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

  12. Method for producing superconductive wires of multifilaments which are encased in copper or a copper alloy and contain niobium and aluminium

    International Nuclear Information System (INIS)

    Flukiger, R.

    1983-01-01

    A method is disclosed for producing a superconductive wire of multifilaments having components comprising niobium and aluminum encased in copper or a copper alloy, wherein the multifilament configuration and the formation of a superconductive A15 phase are positively developed from the components disposed in a copper or copper alloy tube having an interior metallic coating serving as a diffusion barrier, by cold forming and subsequent heat treatment

  13. Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken [Railway Technical Research Institute, 2-8-38 Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan)

    2010-11-15

    We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

  14. Levitation properties of superconducting magnetic bearings using superconducting coils and bulk superconductors

    International Nuclear Information System (INIS)

    Arai, Yuuki; Seino, Hiroshi; Nagashima, Ken

    2010-01-01

    We have been developing a flywheel energy storage system (FESS) with 36 MJ energy capacity for a railway system with superconducting magnetic bearings (SMBs). We prepared two kinds of models using superconducting coils and bulk superconductors (SCs). One model demonstrated SMB load capacity of 20 kN and the other model proved non-contact stable levitation and non-contact rotation with SMBs. Combining these results, the feasibility of a 36 MJ energy capacity FESS with SMBs completely inside a cryostat has been confirmed. In this paper, we report the levitation properties of SMBs in these models.

  15. Superconductivity

    International Nuclear Information System (INIS)

    2007-01-01

    During 2007, a large amount of the work was centred on the ITER project and related tasks. The activities based on low-temperature superconducting (LTS) materials included the manufacture and qualification of ITER full-size conductors under relevant operating conditions, the design of conductors and magnets for the JT-60SA tokamak and the manufacture of the conductors for the European dipole facility. A preliminary study was also performed to develop a new test facility at ENEA in order to test long-length ITER or DEMO full-size conductors. Several studies on different superconducting materials were also started to create a more complete database of superconductor properties, and also for use in magnet design. In this context, an extensive measurement campaign on transport and magnetic properties was carried out on commercially available NbTi strands. Work was started on characterising MgB 2 wire and bulk samples to optimise their performance. In addition, an intense experimental study was started to clarify the effect of mechanical loads on the transport properties of multi-filamentary Nb 3 Sn strands with twisted or untwisted superconducting filaments. The experimental activity on high-temperature superconducting (HTS) materials was mainly focussed on the development and characterisation of YBa 2 Cu 3 O 7-X (YBCO) based coated conductors. Several characteristics regarding YBCO deposition, current transport performance and tape manufacture were investigated. In the framework of chemical approaches for YBCO film growth, a new method, developed in collaboration with the Technical University of Cluj-Napoca (TUCN), Romania, was studied to obtain YBCO film via chemical solution deposition, which modifies the well-assessed metallic organic deposition trifluoroacetate (MOD-TFA) approach. The results are promising in terms of critical current and film thickness values. YBCO properties in films with artificially added pinning sites were characterised in collaboration with

  16. Controllable manipulation of superconductivity using magnetic vortices

    International Nuclear Information System (INIS)

    Villegas, J E; Schuller, Ivan K

    2011-01-01

    The magneto-transport of a superconducting/ferromagnetic hybrid structure, consisting of a superconducting thin film in contact with an array of magnetic nanodots in the so-called 'magnetic vortex state', exhibits interesting properties. For certain magnetic states, the stray magnetic field from the vortex array is intense enough to drive the superconducting film into the normal state. In this fashion, the normal-to-superconducting phase transition can be controlled by the magnetic history. The strong coupling between superconducting and magnetic subsystems allows characteristically ferromagnetic properties, such as hysteresis and remanence, to be dramatically transferred into the transport properties of the superconductor.

  17. Contribution of ion beam analysis methods to the development of 2nd generation high temperature superconducting (HTS) wires

    Energy Technology Data Exchange (ETDEWEB)

    Usov, Igor O [Los Alamos National Laboratory; Arendt, Paul N [Los Alamos National Laboratory; Stan, Liliana [Los Alamos National Laboratory; Holesinger, Terry G [Los Alamos National Laboratory; Foltyn, Steven R [Los Alamos National Laboratory; Depaula, Raymond F [Los Alamos National Laboratory

    2009-01-01

    One of the crucial steps in the second generation high temperature superconducting wire program was development of the buffer layer architecture. The architecture designed at the Superconductivity Technology Center at Los Alamos National Laboratory consists of several oxide layers wherein each layer plays a specific role, namely: nucleation layer, diffusion barrier, biaxially textured template, and an intermediate layer with a good match to the lattice parameter of superconducting Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7} (YBCO) compound. This report demonstrates how a wide range of ion beam analysis techniques (SIMS, RBS, channeling, PIXE, PIGE, NRA, ERD) was employed for analysis of each buffer layer and the YBCO films. These results assisted in understanding of a variety of physical processes occurring during the buffet layer fabrication and helped to optimize the buffer layer architecture as a whole.

  18. Interplay between superconductivity and Coulomb blockade

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Thomas; Sprenger, Susanne; Scheer, Elke [Universitaet Konstanz (Germany)

    2016-07-01

    Studying the interplay between superconductivity and Coulomb blockade (CB) can be achieved by investigating an all superconducting single electron transistor (SSET) consisting of an island coupled to the leads by two tunneling contacts. The majority of experiments performed so far were using superconducting tunnel contacts made from oxide layers, in which multiple Andreev reflections (MAR) can be excluded. Using a mechanically controlled break junction (MCBJ) made of aluminum enables tuning the contributions of MAR in one junction continuously and thereby addressing different transport regimes within the same sample. Our results offer the possibility to attribute particular features in the transport characteristics to the transmission probabilities of individual modes in the MCBJ contact. We discuss our findings in terms of dynamical CB, SSET behaviour and MAR when continuously opening the MCBJ from the fully closed state to a tunneling contact.

  19. Subharmonic energy-gap structure and heating effects in superconducting niobium point contacts

    DEFF Research Database (Denmark)

    Flensberg, K.; Hansen, Jørn Bindslev

    1989-01-01

    We present experimental data of the temperature-dependent subharmonic energy-gap structure (SGS) in the current-voltage (I-V) curves of superconducting niobium point contacts. The observed SGS is modified by heating effects. We construct a model of the quasiparticle conductance of metallic...

  20. A study on the development of high-Tc superconducting wire

    International Nuclear Information System (INIS)

    Won, Dong Yeon; Lee, Hee Gyoun; Kim, Chan Joong

    1991-09-01

    High magnetization YBaCuO superconductor was prepared with additions of BaSnO 3 , SnO 2 and SiC by partial melt processing. Addition of BaSnO 3 increased the magnetic property of YBaCuO by flux pinning action of finely dispersed BaSnO 3 particles, while addition of SnO 2 decreased the magnetic property, because the size of particle was larger than that of BaSnO 3 . BiPbSrCaCuO superconducting tape of single filament was prepared by powder-in-tube method using silver as a shearth material. The fabrication techniques involves powder packing, swaging, drawing and cold rolling/pressing method. The final dimension of wire after drawing is 1.2mm diameter. The wire was pressed into a tape form with a thickness of 70micron and a width of 3mm. The obtained critical current density of the prepared tape was 2000A/cm 2 at 77K. (Author)

  1. Ex-situ manufacturing of SiC-doped MgB2 used for superconducting wire in medical device applications

    Science.gov (United States)

    Herbirowo, Satrio; Imaduddin, Agung; Sofyan, Nofrijon; Yuwono, Akhmad Herman

    2017-02-01

    Magnesium diboride (MgB2) is a superconductor material with a relatively high critical temperature. Due to its relatively high critical temperature, this material is promising and has the potential to replace Nb3Sn for wire superconducting used in many medical devices. In this work, nanoparticle SiC-doped MgB2 superconducting material has been fabricated through an ex-situ method. The doping of nanoparticle SiC by 10 and 15 wt% was conducted to analyze its effect on specific resistivity of MgB2. The experiment was started by weighing a stoichiometric amount of MgB2 and nanoparticles SiC. Both materials were mixed and grounded for 30 minutes by using an agate mortar. The specimens were then pressed into a 6 mm diameter stainless steel tube, which was then reduced until 3 mm through a wire drawing method. X-ray diffraction analysis was conducted to confirm the phase, whereas the superconductivity of the specimens was analyzed by using resistivity measurement under cryogenic magnetic system. The results indicated that the commercial MgB2 showed a critical temperature of 37.5 K whereas the SiC doped MgB2 has critical temperature of 38.3 K.

  2. Superconductivity

    International Nuclear Information System (INIS)

    Taylor, A.W.B.; Noakes, G.R.

    1981-01-01

    This book is an elementray introduction into superconductivity. The topics are the superconducting state, the magnetic properties of superconductors, type I superconductors, type II superconductors and a chapter on the superconductivity theory. (WL)

  3. Superconductivity

    International Nuclear Information System (INIS)

    Onnes, H.K.

    1988-01-01

    The author traces the development of superconductivity from 1911 to 1986. Some of the areas he explores are the Meissner Effect, theoretical developments, experimental developments, engineering achievements, research in superconducting magnets, and research in superconducting electronics. The article also mentions applications shown to be technically feasible, but not yet commercialized. High-temperature superconductivity may provide enough leverage to bring these applications to the marketplace

  4. Superconductivity: materials and applications; La supraconductivite: materiaux et apllications

    Energy Technology Data Exchange (ETDEWEB)

    Duchateau, J.L. [CEA Cadarache, 13 - Saint Paul lez Durance (France); Kircher, F. [CEA Saclay, 91 - Gif sur Yvette (France); Leveque, J. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, GREEN - UHP, 54 - Vandoeuvre les Nancy (France); Tixador, P. [INP/Institut Neel, 38 - Grenoble (France)

    2008-07-01

    This digest paper presents the different types of superconducting materials: 1 - the low-TC superconductors: the multi-filament composite as elementary constituent, the world production of NbTi, the superconducting cables of the LHC collider and of the ITER tokamak; 2 - the high-TC superconductors: BiSrCaCuO (PIT 1G) ribbons and wires, deposited coatings; 3 - application to particle physics: the the LHC collider of the CERN, the LHC detectors; 4 - applications to thermonuclear fusion: Tore Supra and ITER tokamaks; 5 - NMR imaging: properties of superconducting magnets; 6 - applications in electrotechnics: cables, motors and alternators, current limiters, transformers, superconducting energy storage systems (SMES). (J.S.)

  5. Laser patterning of superconducting oxide films

    International Nuclear Information System (INIS)

    Gupta, A.; Hussey, B.W.; Koren, G.; Cooper, E.I.; Jagannathan, R.

    1988-01-01

    The focused output of an argon ion laser (514.5 nm) has been used for wiring superconducting lines of Y/sub 1/Ba/sub 2/CU/sub 3/O/sub 7-δ/ using films prepared from nitrate and trifluoroacetate solution precursors. A stoichiometric solution of the precursors is sprayed or spun on to the substrate to form a film. The film is patterned by irradiating in selected areas to convert the irradiated layers to an intermediate oxide or fluoride state, the nonirradiated areas being unchanged. The nonirradiated areas are then dissolved away, leaving a pattern of the oxide or fluoride material. This patterned layer is converted to the superconducting 1-2-3 oxide in a subsequent annealing step. Maskless patterning of superconducting films has also been demonstrated by laser-assisted etching of the films in aqueous KOH solution. Although superconductivity is destroyed when the films are placed in solution, it can be restored after a brief anneal in oxygen

  6. Theory of superconductivity

    International Nuclear Information System (INIS)

    Crisan, M.

    1988-01-01

    This book discusses the most important aspects of the theory. The phenomenological model is followed by the microscopic theory of superconductivity, in which modern formalism of the many-body theory is used to treat most important problems such as superconducting alloys, coexistence of superconductivity with the magnetic order, and superconductivity in quasi-one-dimensional systems. It concludes with a discussion on models for exotic and high temperature superconductivity. Its main aim is to review, as complete as possible, the theory of superconductivity from classical models and methods up to the 1987 results on high temperature superconductivity. Contents: Phenomenological Theory of Superconductivity; Microscopic Theory of Superconductivity; Theory of Superconducting Alloys; Superconductors in a Magnetic Field; Superconductivity and Magnetic Order; Superconductivity in Quasi-One-Dimensional Systems; and Non-Conventional Superconductivity

  7. Applied superconductivity

    CERN Document Server

    Newhouse, Vernon L

    1975-01-01

    Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

  8. Hofstadter's Butterfly and Phase Transition of Checkerboard Superconducting Network in a Magnetic Field

    International Nuclear Information System (INIS)

    Hou Jingmin; Tian, Li-Jim

    2010-01-01

    We study the magnetic effect of the checkerboard superconducting wire network. Based on the de Gennes-Alexader theory, we obtain difference equations for superconducting order parameter in the wire network. Through solving these difference equations, we obtain the eigenvalues, linked to the coherence length, as a function of magnetic field. The diagram of eigenvalues shows a fractal structure, being so-called Hofstadter's butterfly. We also calculate and discuss the dependence of the transition temperature of the checkerboard superconducting wire network on the applied magnetic field, which is related to up-edge of the Hofstadter's butterfly spectrum. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  9. Development of high field superconducting magnet

    International Nuclear Information System (INIS)

    Irie, Fujio; Takeo, Masakatsu.

    1986-01-01

    Recently, in connection with nuclear fusion research, the development of high field superconducting magnets showed rapid progress. The development of high field magnets of 15 T class by the techniques of winding after heat treatment has been continued in various places, as these techniques are suitable to make large magnets. In 1985, Kyushu University attained the record of 15.5 T. However in high field magnets, there are many problems peculiar to them, and the basic research related to those is demanded. In this report, these general problems, the experience of the design and manufacture in Kyushu University and the related problems are described. The superconducting magnet installed in the Superconducting Magnet Research Center of Kyushu University attained the record of 15.5 T for the first time in March, 1985. In superconducting magnets, very difficult problem must be solved since superconductivity, heat and mechanical force are inter related. The problems of the wire materials for high field, the scale of high field magnets, the condition limiting mean current density, and the development of high field magnets in Kyushu University are described. (Kako, I.)

  10. Low AC-Loss Superconducting Cable Technology for Electric Aircraft Propulsion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The availability of low AC loss magnesium diboride (MgB2) superconducting wires enables much lighter weight superconducting stator coils than with any other metal or...

  11. Development of 'low activation superconducting wire' for an advanced fusion reactor

    International Nuclear Information System (INIS)

    Hishinuma, Y.; Yamada, S.; Sagara, A.; Kikuchi, A.; Takeuchi, T.; Matsuda, K.; Taniguchi, H.

    2011-01-01

    In the D-T burning plasma reactor beyond ITER such as DEMO and fusion power plants assuming the steady-state and long time operation, it will be necessary to consider carefully induced radioactivity and neutron irradiation properties on the all components for fusion reactors. The decay time of the induced radioactivity can control the schedule and scenarios of the maintenance and shutdown on the fusion reactor. V 3 Ga and MgB 2 compound have shorter decay time within 1 years and they will be desirable as a candidate material to realize 'low activation and high magnetic field superconducting magnet' for advanced fusion reactor. However, it is well known that J c -B properties of V 3 Ga and MgB 2 wires are lower than that of the Nb-based A15 compound wires, so the J c -B enhancements on the V 3 Ga and MgB 2 wires are required in order to apply for an advanced fusion reactor. We approached and succeeded to developing the new process in order to improve J c properties of V 3 Ga and MgB 2 wires. In this paper, the recent activities for the J c improvements and detailed new process in V 3 Ga and MgB 2 wires are investigated. (author)

  12. Superconductivity

    International Nuclear Information System (INIS)

    Caruana, C.M.

    1988-01-01

    Despite reports of new, high-temperature superconductive materials almost every day, participants at the First Congress on Superconductivity do not anticipate commercial applications with these materials soon. What many do envision is the discovery of superconducting materials that can function at much warmer, perhaps even room temperatures. Others hope superconductivity will usher in a new age of technology as semiconductors and transistors did. This article reviews what the speakers had to say at the four-day congress held in Houston last February. Several speakers voiced concern that the Reagan administration's apparent lack of interest in funding superconductivity research while other countries, notably Japan, continue to pour money into research and development could hamper America's international competitiveness

  13. Limiting currents in superconducting composites

    International Nuclear Information System (INIS)

    Keilin, V.E.; Romanovskii, V.R.

    1992-01-01

    In this paper the results of numerical and analytical calculations of the process of current charging into a round superconducting composite with properties homogenized over cross-section are presented. In the numerical solution taken was into account a common proceeding of the thermal and electromagnetic processes. A wire with real volt-ampere characteristics approximated by exponential dependence was considered. The calculations carried out at various rates of current charging, voltampere characteristics, matrix materials, heat transfer coefficients and other parameters showed: the existence of characteristic limiting value of current below which the wire remains in a superconducting state if the current charging ceases and above which changes into a normal state; this current is somewhat less than a quench current; the existence of finite value for limiting current at any low heat transfer from a surface. The analytical solution of the problem is given. It permitted to write the stability criterion from which the dependence of limiting currents on initial parameters follows. The wire nonisothermality, its heat capacity, thermal and electric conductivities are taken into account additionally, as compared to results published earlier

  14. Magnesium Diboride Superconducting Coils for Electric Propulsion Systems for Large Aircraft, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The recent development of magnesium diboride superconducting wires makes possible the potential to have much lighter weight superconducting coils for heavy aircraft...

  15. Advantage and Challenges of $Nb_3Sn$ Superconducting Undulators

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A. V. [Fermilab; Barzi, E. [Fermilab; Turrinoni, D. [Fermilab; Ivanyushenkov, Yu. [Argonne; Kesgin, I. [Argonne

    2018-04-01

    Utilization of Nb3Sn superconducting wires offers the possibility to increase undulators’ nominal operation field and temperature margin, but requires overcoming chal-lenges that are described in this paper. The achievable field levels for a Nb3Sn version of superconducting undulators being developed at APS-ANL and the conductor choice are also presented and discussed.

  16. Development and fabrication of superconducting hybrid Cable-In-Conduit-Conductor (CICC) for indigenous fusion programme

    International Nuclear Information System (INIS)

    Singh, A.K.; Hussain, M.M.; Abdulla, K.K.; Singh, R.P.

    2011-01-01

    The Atomic Fuels Division has initiated development and fabrication of Cable-In-Conduit-Conductor (CICC) of various configurations, for superconducting fusion grade magnets required for their indigenous Fusion Programme. The process involves development of high grade superconducting multifilamentary wire, multi stage cabling of superconducting as well as copper wires and, finally, jacketing of the cables in SS316LN tubes. The overview of the development and fabrication of CICC is presented in this article. (author)

  17. Tuning the Superconducting Properties of Magnesium Diboride

    Energy Technology Data Exchange (ETDEWEB)

    Theoderich Wilke, Rudeger Heinrich [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    This work is presented in the following order: A review of the relevant physics and discussion of theoretical predictions for a two gap superconducting compound is given in chapter 2. Chapter 3 provides a review of the basic properties of MgB2. Details of sample synthesis and characterization are given in chapter 4. Chapter 5 presents normal state and superconducting properties of Mg(B1-xCx)2 wires. Attempts to increase critical current densities in filaments via titanium additions are discussed in chapter 6. In chapters 7 and 8 alternative methods for synthesizing doped MgB2 powders are explored. In chapter 7 we synthesize Mg(B1-xCx)2 up to x=0.069 using a mixture of Mg, B, and the binary compound B4C. Chapter 8 explores an alternative method, plasma spray synthesis, to produce nanometer sized doped boron powders for powder-in-tube applications. The effects of neutron irradiation on pure MgB2 wires is discussed in chapter 9. This is followed by a study of the effects of neutron irradiation on Mg(B.962C.038)2 wires, presented in chapter 10. I will summarize the results of all of these studies in chapter 11 and discuss future directions for research in understanding the physics behind this novel material as well as its development for practical applications. In this thesis I have presented the results of investigations into the changes in the superconducting properties of MgB2 as a function of carbon doping and neutron irradiation. The goal has been to understand the physics underlying this unique two-gap superconductor as different types of perturbations are made to the system. Such knowledge not only contributes to our understanding of two-gap superconductivity, but could potentially lead to the development of superconducting MgB2 wires for the use in power applications near 20 K.

  18. Test results of a 5 kW fully superconducting homopolar motor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. K. [Woosuk University, Wanju (Korea, Republic of); Park, S. H.; Kim, Y.; Lee, S.; Joo, H. G.; Kim, W. S.; Choi, K. [Korea Polytechnic University,Siheong (Korea, Republic of); Hahm, S. Y. [Electrical Engineering and Science Research Institute,Seoul (Korea, Republic of)

    2013-05-15

    The superconducting Homopolar motor is manufactured and tested. Homopolar motor system is simple and solid as the field coil of the motor is fixed near the stator coil without rotating system. In this paper, a 5 kW fully superconducting homopolar motor which has high temperature superconducting armature and field coils is manufactured and tested in liquid nitrogen. The critical current test results of the used 2G superconducting wire, pancake coil for rotor winding and race-track coils for armature winding are reported. Also, the test result of rotating and operating performance is presented. The operating frequency is to be 5 Hz for low-speed rotating. The developed fully superconducting Homopolar motor is the world's first.

  19. Test results of a 5 kW fully superconducting homopolar motor

    International Nuclear Information System (INIS)

    Lee, J. K.; Park, S. H.; Kim, Y.; Lee, S.; Joo, H. G.; Kim, W. S.; Choi, K.; Hahm, S. Y.

    2013-01-01

    The superconducting Homopolar motor is manufactured and tested. Homopolar motor system is simple and solid as the field coil of the motor is fixed near the stator coil without rotating system. In this paper, a 5 kW fully superconducting homopolar motor which has high temperature superconducting armature and field coils is manufactured and tested in liquid nitrogen. The critical current test results of the used 2G superconducting wire, pancake coil for rotor winding and race-track coils for armature winding are reported. Also, the test result of rotating and operating performance is presented. The operating frequency is to be 5 Hz for low-speed rotating. The developed fully superconducting Homopolar motor is the world's first.

  20. Beating liquid helium: the technologies of cryogen-free superconducting magnets

    Science.gov (United States)

    Burgoyne, John

    2015-03-01

    Cryogen-free superconducting magnets have been available now for almost 15 years, but have only become standard commercial products in more recent years. In this review we will consider the pros and cons of ``dry'' design including superconducting wire development and selection, thermal budgeting, and the alternative methods for achieving magnet cooling.

  1. A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Z; Jiang, Y; Pei, R; Coombs, T A [Electronic, Power and Energy Conversion Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Ye, L [Department of Electrical Power Engineering, CAU, P. O. Box 210, Beijing 100083 (China); Campbell, A M [Interdisciplinary Research Centre in Superconductivity, University of Cambridge, CB3 0HE (United Kingdom)], E-mail: Zh223@cam.ac.uk

    2008-02-15

    In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB{sub 2} wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB{sub 2} wires. The results demonstrate that the multi-element MgB{sub 2} wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement.

  2. Diamagnetism in quasicrystalline superconducting networks

    International Nuclear Information System (INIS)

    Qian Niu; Nori, F.

    1990-01-01

    In this paper, we review recent results on superconducting structures with quasicrystalline geometry. Specifically, we consider the superconducting-normal phase boundaries of a variety of wire networks and Josephson junction arrays. We have computed the mean field phase diagrams for a number of geometries and compared them to the corresponding experimental data. We have introduced an analytical approach to the analysis of the structures present in the phase boundaries. Furthermore, we have shown in great detail how the gross structure is determined by the statistical distributions of the cell areas, and how the fine structures are determined by correlations among neighboring cells in the lattices. (author). 12 refs, 2 figs

  3. A jelly-roll process for high temperature superconducting tapes and wires

    International Nuclear Information System (INIS)

    Tsuei, C.C.; Chi, C.C.; Frey, T.; Mitzi, D.B.; Kazyaka, T.; Haugan, T.; Ye, J.; Patel, S.; Shaw, D.T.; Wu, M.K.

    1992-01-01

    As an alternative to the powder-in-tube method, a new technique called the jelly-roll process is proposed for making high-T c superconducting tapes and wires. A normal-metal sheet coated with high-T c cuprate is configured in a jelly-roll fashion and cold worked into tapes or wires made of alternating cuprate superconductor and normal metal layers. The feasibility of this new process is demonstrated for both the YBa 2 Cu 3 O 7 /Ag and Bi 2 Sr 2 CaCu 2 O 8 /Ag composite systems. The role of reduction in the cross-sectional area by cold-rolling, heat treatment and oxygenation in optimizing T c and J c has been studied. Preliminary results indicate that partialmelt texturing, in the Bi 2 Sr 2 CaCu 2 O 8 /Ag system, results in a relatively field independent J c (H c (H = 0) ∝5 X 10 4 A cm -2 at 4.2 K

  4. Realization of superconductive films by screen printing

    International Nuclear Information System (INIS)

    Baudry, H.

    1988-01-01

    Screen printing is a promising method to manufacture superconductive lines making use of superconductive ceramics. An ink has been realized with YBa 2 Cu 3 0 7-x' and the process conditions defined by thermal analysis. A superconductive transition is observed after screen printing on MgO. The firing of the layer is made at 920 0 C followed by a reoxidation step at 420 0 C. The silver electrical contacts are also screen printed [fr

  5. Superconducting homopolar motor and conductor development

    Science.gov (United States)

    Gubser, Donald U.

    1996-10-01

    The U.S. Navy has been developing superconducting homopolar motors for ship applications since 1969; a successful at-sea demonstration of the first motor, using NbTi wire for the magnet, was achieved in the early 1980s. Recently, this same motor was used as a test bed to demonstrate progress in high-critical-temperature superconducting magnet technology using bismuth-strontium- calcium-copper-oxide (BSCCO) compounds. In the fall of 1995, this motor achieved a performance of 124 kW operating at a temperature of 4.2 K and 91 kW while operating at 28 K. Future tests are scheduled using new magnets with conductors of both the 2223 and the 2212 BSCCO phases. This article describes the advantages of superconducting propulsion and recent progress in the development of BSCCO conductors for use in Navy power systems.

  6. Pantechnik new superconducting ion source: PantechniK Indian Superconducting Ion Source

    International Nuclear Information System (INIS)

    Gaubert, G.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Leroy, R.; Sineau, A.; Vallerand, C.; Villari, A. C. C.; Thuillier, T.

    2012-01-01

    The new ECR ion source PantechniK Indian Superconducting Ion Source (PKISIS) was recently commissioned at Pantechnik. Three superconducting coils generate the axial magnetic field configuration, while the radial magnetic field is done with the multi-layer permanent magnets. Special care was devoted to the design of the hexapolar structure, allowing a maximum magnetic field of 1.32 T at the wall of the 82 mm diameter plasma chamber. The three superconducting coils using low temperature superconducting wires are cooled by a single double stage cryo-cooler (4.2 K). Cryogen-free technology is used, providing reliability and easy maintenance at low cost. The maximum installed RF power (18.0 GHz) is of 2 kW. Metallic beams can be produced with an oven (T max = 1400 deg. C) installed with an angle of 5 deg. with respect to the source axis or a sputtering system, mounted on the axis of the source. The beam extraction system is constituted of three electrodes in accel-decel configuration. The new source of Pantechnik is conceived for reaching optimum performances at 18 GHz RF frequencies. PKISIS magnetic fields are 2.1 T axial B inj and 1.32 T radial field in the wall, variable B min with an independent coil and a large and opened extraction region. Moreover, PKISIS integrates modern design concepts, like RF direct injection (2 kW availability), dc-bias moving disk, out-of-axis oven and axial sputtering facility for metal beams. Finally, PKISIS is also conceived in order to operate in a high-voltage platform with minor power consumption.

  7. The quality assurance of superconducting wire and cable for SSC magnets

    International Nuclear Information System (INIS)

    Pollock, D.; Baggett, P.; Capone, D.

    1991-03-01

    The success of the SSC depends on the consistency and uniformity of the superconducting magnets used in the main collider rings and the high energy booster. To a great extent the success of the magnets depends upon the quality of the superconductor wire and cable used in coil windings. As the SSC project has begun its transition from Research to Development, a new laboratory organization has been established to carry the design requirements from concept to reality. The SSCL Magnet Systems Division Quality Assurance Group has been working on the development of a quality management and analysis system for insuring superconductor uniformity through the understanding and control of manufacturing variation. Key areas of the QA activity include: the design and development of a computer database and analysis system for the collection and statistical analysis of superconductor materials data (containing: source physical and chemical properties, billet process history, and final product performance data); and the development of wire and cable product specifications which focus on the control of variation. As a result of this work several new concepts have been developed which will affect the traditional approach to superconductor wire and cable production. 18 refs., 5 figs., 1 tab

  8. Interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gariglio, S., E-mail: stefano.gariglio@unige.ch [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland); Gabay, M. [Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud 11, Centre d’Orsay, 91405 Orsay Cedex (France); Mannhart, J. [Max Planck Institute for Solid State Research, 70569 Stuttgart (Germany); Triscone, J.-M. [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland)

    2015-07-15

    Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3} are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO{sub 3} and SrTiO{sub 3}. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO{sub 3} and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3}.

  9. Thermal properties of a large-bore cryocooled 10 T superconducting magnet for a hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, M.; Hamajima, T.; Itou, T.; Sakuraba, J.; Nishijima, G.; Awaji, S.; Watanabe, K.

    2010-01-01

    A cryocooled 10 T superconducting magnet with a 360 mm room temperature bore has been developed for a hybrid magnet. The superconducting magnet cooled by four Gifford-McMahon cryocoolers has been designed to generate a magnetic field of 10 T. Since superconducting wires composed of coils were subjected to large hoop stress over 150 MPa and Nb 3 Sn superconducting wires particularly showed a low mechanical strength due to those brittle property, Nb 3 Sn wires strengthened by NbTi-filaments were developed for the cryocooled superconducting magnet. We have already reported that the hybrid magnet could generate the resultant magnetic field of 27.5 T by adding 8.5 T from the superconducting magnet and 19 T from a water-cooled Bitter resistive magnet, after the water-cooled resistive magnet was inserted into the 360 mm room temperature bore of the cryocooled superconducting magnet. When the hybrid magnet generated the field of 27.5 T, it achieved the high magnetic-force field (B x ∂Bz/∂z) of 4500 T 2 /m, which was useful for magneto-science in high fields such as materials levitation research. In this paper, we particularly focus on the cause that the cryocooled superconducting magnet was limited to generate the designed magnetic field of 10 T in the hybrid magnet operation. As a result, it was found that there existed mainly two causes as the limitation of the magnetic field generation. One was a decrease of thermal conductive passes due to exfoliation from the coil bobbin of the cooling flange. The other was large AC loss due to both a thick Nb 3 Sn layer and its large diameter formed on Nb-barrier component in Nb 3 Sn wires.

  10. Superconducting coil and method of stress management in a superconducting coil

    Science.gov (United States)

    McIntyre, Peter M.; Shen, Weijun; Diaczenko, Nick; Gross, Dan A.

    1999-01-01

    A superconducting coil (12) having a plurality of superconducting layers (18) is provided. Each superconducting layer (18) may have at least one superconducting element (20) which produces an operational load. An outer support structure (24) may be disposed outwardly from the plurality of layers (18). A load transfer system (22) may be coupled between at least one of the superconducting elements (20) and the outer support structure (24). The load transfer system (22) may include a support matrix structure (30) operable to transfer the operational load from the superconducting element (20) directly to the outer support structure (24). A shear release layer (40) may be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a shear stress between the superconducting element (20) and the support matrix structure (30). A compliant layer (42) may also be disposed, in part, between the superconducting element (20) and the support matrix structure (30) for relieving a compressive stress on the superconducting element (20).

  11. Analysis of the trade-offs between conventional and superconducting interconnections

    International Nuclear Information System (INIS)

    Frye, R.

    1989-01-01

    Superconductivity can now be achieved at temperatures compatible with semiconductor device operation. This raises the interesting possibility of using the new, high-temperature superconducting ceramics for interconnections in electronic systems. This paper examines some of the consequences of a resistance-free interconnection medium. A problem with conventional conductors in electronic systems is that the resistance of wires increases quadratically as the wire dimensions are scaled down. Below some minimum cross-sectional area, determined by the metal resistivity and wire length, the resistance in these lines begins to severely limit their bandwidth. Superconductors, on the other hand, are not constrained by the same scaling rules. They provide a high bandwidth interconnection at all sizes and lengths. The limitations for superconductors are set by their critical current densities. If line dimensions become too small, a superconductor will no longer support an adequate flow of current. An analysis is presented examining the performance trade-offs for conventional and superconducting interconnections in applications ranging from printed wiring boards to chips. For most semiconductor device-based applications, the potential gains in wiring density offered by superconductors are probably more important than the bandwidth improvements. An important result of the analysis is that it determines the values of critical current density above which superconductors outperform conventional wires in systems of various physical sizes. This identifies particular interconnection technologies for which high-temperature superconductors show the most promise

  12. Superconductivity

    International Nuclear Information System (INIS)

    Kakani, S.L.; Kakani, Shubhra

    2007-01-01

    The monograph provides readable introduction to the basics of superconductivity for beginners and experimentalists. For theorists, the monograph provides nice and brief description of the broad spectrum of experimental properties, theoretical concepts with all details, which theorists should learn, and provides a sound basis for students interested in studying superconducting theory at the microscopic level. Special chapter on the theory of high-temperature superconductivity in cuprates is devoted

  13. Magnetic signature of granular superconductivity in electrodeposited Pb nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Riminucci, Alberto, E-mail: a.riminucci@bo.ismn.cnr.it [CNR, Institute for Nanostructured Materials, Via Gobetti 101, 40129 Bologna (Italy); H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Schwarzacher, Walther [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2014-06-14

    Nanocrystalline freestanding Pb nanowires ∼200 nm in diameter were fabricated by electrodeposition into track etched polycarbonate membranes in order to study their superconducting properties. Their superconducting critical temperature, as determined by measuring the Meissner effect, was the same as for bulk Pb, but their critical field was greatly enhanced up to ∼3000 Oe. By assuming the wires consisted of spherical superconducting grains, an estimated grain size r = 60 ± 25 nm was obtained from the magnetization measured as a function of the applied magnetic field at a fixed temperature. An independent estimate for r = 47 ± 12 nm, in good agreement with the previous one, was obtained from the magnetization measured as a function of temperature at a fixed applied magnetic field. Transmission electron microscopy was used to characterize grain size at the wire edges, where a grain size in agreement with the magnetic studies was observed.

  14. Superconductivity

    International Nuclear Information System (INIS)

    Langone, J.

    1989-01-01

    This book explains the theoretical background of superconductivity. Includes discussion of electricity, material fabrication, maglev trains, the superconducting supercollider, and Japanese-US competition. The authors reports the latest discoveries

  15. ac superconducting articles

    International Nuclear Information System (INIS)

    Meyerhoff, R.W.

    1977-01-01

    A noval ac superconducting cable is described. It consists of a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface

  16. High-temperature superconductivity

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1987-07-01

    After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

  17. Superconducting accelerator technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Hartline, B.K.

    1986-01-01

    Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

  18. Superconducting magnets for HERA

    International Nuclear Information System (INIS)

    Wolff, S.

    1987-01-01

    The Hadron-Electron-Ring Accelerator (HERA) presently under construction at DESY, Hamburg, consists of an electron storage ring of 30 GeV and a proton storage ring of 820 GeV. Superconducting magnets are used for the proton ring. There are 416 superconducting bending magnets of 4.698 T central field and 8.824 m magnetic length, 224 superconducting quadrupoles of 91.2 T/m central gradient and many superconducting correction dipoles, quadrupoles and sextupoles. The main dipoles and quadrupoles consist of two-layer coils of 75 mm inner diameter clammed with aluminium (for the dipoles) or stainless steel laminations (for the quadrupoles). The collared coils are surrounded by a laminated cold iron yoke and supported inside a low loss cryostat. The protection system uses cold diodes to bypass the current around a quenching magnet. The magnets are cooled with one phase helium supplied by a 3 block central refrigeration system of 20 kW refrigeration power at 4.3 K. Two helium is returned through the magnets in good thermal contact with the one phase helium in the dipoles for temperature control. This paper describes the magnet system and gives the results obtained for prototype magnets

  19. Lightweight MgB2 superconducting 10 MW wind generator

    Science.gov (United States)

    Marino, I.; Pujana, A.; Sarmiento, G.; Sanz, S.; Merino, J. M.; Tropeano, M.; Sun, J.; Canosa, T.

    2016-02-01

    The offshore wind market demands a higher power rate and more reliable turbines in order to optimize capital and operational costs. The state-of-the-art shows that both geared and direct-drive conventional generators are difficult to scale up to 10 MW and beyond due to their huge size and weight. Superconducting direct-drive wind generators are considered a promising solution to achieve lighter weight machines. This work presents an innovative 10 MW 8.1 rpm direct-drive partial superconducting generator using MgB2 wire for the field coils. It has a warm iron rotor configuration with the superconducting coils working at 20 K while the rotor core and the armature are at ambient temperature. A cooling system based on cryocoolers installed in the rotor extracts the heat from the superconducting coils by conduction. The generator's main parameters are compared against a permanent magnet reference machine, showing a significant weight and size reduction. The 10 MW superconducting generator concept will be experimentally validated with a small-scale magnetic machine, which has innovative components such as superconducting coils, modular cryostats and cooling systems, and will have similar size and characteristics as the 10 MW generator.

  20. High Temperature Superconducting Underground Cable

    International Nuclear Information System (INIS)

    Farrell, Roger A.

    2010-01-01

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  1. Influence of Ni and Cu contamination on the superconducting properties of MgB2 filaments

    International Nuclear Information System (INIS)

    Jung, A; Schlachter, S I; Runtsch, B; Ringsdorf, B; Fillinger, H; Orschulko, H; Drechsler, A; Goldacker, W

    2010-01-01

    Technical MgB 2 wires usually have a sheath composite consisting of different metals. For the inner sheath with direct contact to the superconducting filament, chemically inert Nb may be used as a reaction barrier and thermal stabilization is provided by a highly conductive metal like Cu. A mechanical reinforcement can be achieved by the addition of stainless steel. In order to illuminate the influence of defects in the reaction barrier, monofilament in situ wires with direct contact between the MgB 2 filament and frequently applied reactive sheath metals like Cu, Ni or Monel are studied. Reactions of Mg and B with a Cu-containing sheath lead to Cu-based by-products penetrating the whole filament. Reactions with Ni-containing sheaths lead to Ni-based by-products which tend to remain at the filament-sheath interface. Cu and/or Ni contamination of the filament lowers the MgB 2 -forming temperature due to the eutectic reaction between Mg, Ni and Cu. Thus, for the samples heat-treated at low temperatures J C and (partly) T C are increased compared to stainless-steel-sheathed wires. At high heat treatment temperatures uncontaminated filaments lead to the highest J C values. From the point of view of broken reaction barriers in real wires, the contamination of the filament with Cu and/or Ni does not necessarily constrain the superconductivity; it may even improve the properties of the wire, depending on the desired application.

  2. Microstructures and superconducting properties of Y-Ba-Cu and Bi-Sr-Ca-Cu oxide wires and coils prepared by the explosive compaction technique

    International Nuclear Information System (INIS)

    Hagino, S.; Suzuki, M.; Takeshita, T.; Takashima, K.; Tonda, H.

    1989-01-01

    It has been shown that explosive compaction technique can be used to densify metal, and ceramics powders and their mixtures. The authors discuss how they applied this technique to produce silver sheathed superconducting oxide wires and coils (Y-B-Cu-O and Bi-Sr-Ca-Cu-O). The wires and coils to be compacted were placed into metal tube and the tube was filled with SiC powder as a pressure propagating medium and the tube was compacted by a cylindrically axisymmetric method. The wires and coils compacted were then heat-treated in order to improve grain boundary connections of superconducting oxide crystalline grains. The oxide cores heat-treated were seen to be very dense, and a part of a Y-Ba-Cu oxide coil which was heat-treated optimally was found to have a critical current density higher than 13,000A/cm 2 at 77K

  3. Manufacture of superconducting wire. Progress report, February 1-October 15, 1979

    International Nuclear Information System (INIS)

    Avitzur, B.; Chou, Y.T.; Talbert, S.; Wu, R.

    1979-10-01

    This report is divided into three major sections. The first section covers aspects of the manufacturing technology with existing and potential processes, and the second deals with the analysis of flow and fracture and the derivation of criteria to prevent failure. In the first section, typical present-day procedure to assemble a billet, extrude and draw it, with intermediate and final anneals, is described. Then an hypothetical production line with potential alternative processes along the entire path from heavy billet to fine wire, is laid out. Several processes at different stages of development, are offered. In the second section the analysis of core fracture and its prevention during the process of drawing is provided. Treatment of velocity fields for a bi-metallic rod leads to the determination of criteria for the prevention of fracture. The criteria are presented graphically. The third section describes work on micro properties of superconducting wires. A modification of the bronze method for niobium-tin superconductors is proposed and a preliminary schedule of the testing procedures is outlined

  4. 10th International Symposium on Superconductivity

    CERN Document Server

    Hirabayashi, Izumi

    1998-01-01

    The International Symposium on Superconductivity, which has been held annu­ ally since 1988, is a forum for presenting the most up-to-date information about a broad range of research and development in superconductivity, from funda­ mental aspects to applications. More than 10 years have passed since the discovery of oxide superconductors and since various developments of applications began. It may be said that the prospects for application of oxide superconductors recently have opened up. Great progress has been made toward practical use, for example, of the flywheel, which uses bulk materials, and the high-performance cryo-cooled magnet made of bismuth wire. These were the results of persistent efforts to develop materials from the viewpoint of materials science and engineering. Also important is the progress in comprehensive understanding of high­ temperature superconductivity. Unique electronic properties of cuprates such as the non-Fermi liquid normal state, spin-charge separation, spin gap, and d-wav...

  5. Electrical protection of superconducting magnet systems

    International Nuclear Information System (INIS)

    Sutter, D.F.; Flora, R.H.

    1975-01-01

    The problem of dissipating the energy stored in the field of a superconducting magnet when a quench occurs has received considerable study. However, when the magnet becomes a system 4 miles in length whose normal operation is an ac mode, some re-examination of standard techniques for dissipating energy outside the magnets is in order. Data accumulated in the Fermilab Energy Doubler magnet development program shows that heating associated with the temporal and spatial development of quenches is highly localized and can result in temperatures damaging to the superconducting wire. The design and operation are discussed for several energy dumping schemes, compatible with the operation of ac superconducting magnets, wherein more than 70 percent of the stored energy can be dissipated outside the magnet. Instrumentation to detect quenches early in their development and circuits for dumping the field energy are described, and representative operating performance data for the dump circuits and data showing temporal development of quenches are presented. (auth)

  6. Designing of superconducting magnet for clinical MRI

    International Nuclear Information System (INIS)

    Kar, Soumen; Choudhury, A.; Sharma, R.G.; Datta, T.S.

    2015-01-01

    Superconducting technology of Magnetic Resonance Imaging (MRI) scanner is closely guarded technology as it has huge commercial application for clinical diagnostics. This is a rapidly evolving technology which requires innovative design of magnetic and cryogenic system. A project on the indigenous development of 1.5 T (B_0) MRI scanner has been initiated by SAMEER, Mumbai funded by DeitY, Gov. of India. IUAC is the collaborating institute for designing and developing the superconducting magnets and the cryostat for 1.5 T MRI scanner. The superconducting magnet is heart of the present day MRI system. The performance of the magnet has the highest impact on the overall image quality of the scanner. The stringent requirement of the spatial homogeneity (few parts per million within 50 cm diametrical spherical volume), the temporal stability (0.1 ppm/hr.) of the superconducting magnet and the safety standard (5 G in 5 m x 3 m ellipsoidal space) makes the designing of the superconducting magnet more complex. MRI consists of set of main coils and shielding coils. The large ratio between the diameter and the winding length of each coil makes the B_p_e_a_k/B_0 ratio much higher, which makes complexity in selecting the load line of the magnet. Superconducting magnets will be made of NbTi wire-in-channel (WIC) conductor with high copper to superconducting (NbTi) ratio. Multi-coil configuration on multi-bobbin architecture is though is cost effective but poses complexity in the mechanical integration to achieve desired homogeneity. Some of the major sources of inhomogeneities, in a multi-bobbin configuration, are the imperfect axial positioning and angular shift. We have simulated several factors which causes the homogeneity in six (main) coils configuration for a 1.5 T MRI magnet. Differential thermal shrinkage between the bobbin and superconducting winding is also a major source of inhomogeneity in a MRI magnet. This paper briefly present the different designing aspects of the

  7. Quantum interferometer based on GaAs/InAs core/shell nanowires connected to superconducting contacts

    Science.gov (United States)

    Haas, F.; Dickheuer, S.; Zellekens, P.; Rieger, T.; Lepsa, M. I.; Lüth, H.; Grützmacher, D.; Schäpers, Th

    2018-06-01

    An interferometer structure was realized based on a GaAs/InAs core/shell nanowire and Nb superconducting electrodes. Two pairs of Nb contacts are attached to the side facets of the nanowire allowing for carrier transport in three different orientations. Owing to the core/shell geometry, the current flows in the tubular conductive InAs shell. In transport measurements with superconducting electrodes directly facing each other, indications of a Josephson supercurrent are found. In contrast for junctions in diagonal and longitudinal configuration a deficiency current is observed, owing to the weaker coupling on longer distances. By applying a magnetic field along the nanowires axis pronounced h/2e flux-periodic oscillations are measured in all three contact configurations. The appearance of these oscillations is explained in terms of interference effects in the Josephson supercurrent and long-range phase-coherent Andreev reflection.

  8. Superconductivity

    CERN Document Server

    Ketterson, John B

    2008-01-01

    Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

  9. Experimental studies of the quench behaviour of MgB{sub 2} superconducting wires for fault current limiter applications

    Energy Technology Data Exchange (ETDEWEB)

    Ye Lin [Interdisciplinary Research Center (IRC) in Superconductivity, Cavendish Laboratory/Department of Engineering, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Majoros, M [Laboratories for Applied Superconductivity and Magnetism, Ohio State University, Columbus, OH 43210 (United States); Campbell, A M [Interdisciplinary Research Center (IRC) in Superconductivity, Cavendish Laboratory/Department of Engineering, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Coombs, T [Interdisciplinary Research Center (IRC) in Superconductivity, Cavendish Laboratory/Department of Engineering, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Astill, D [Interdisciplinary Research Center (IRC) in Superconductivity, Cavendish Laboratory/Department of Engineering, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Harrison, S [Scientific Magnetics, Culham Science Centre, Culham, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Husband, M [Strategic Research Center (SRC)-Electrical Engineering, Rolls-Royce plc, Derby DE24 8BJ (United Kingdom); Rindfleisch, M [Hyper Tech Research Inc., Columbus, OH 43212 (United States); Tomsic, M [Hyper Tech Research Inc., Columbus, OH 43212 (United States)

    2007-07-15

    Various MgB{sub 2} wires with different sheath materials provided by Hyper Tech Research Inc., have been tested in the superconducting fault current limiter (SFCL) desktop tester at 24-26 K in a self-field. Samples 1 and 2 are similarly fabricated monofilamentary MgB{sub 2} wires with a sheath of CuNi, except that sample 2 is doped with SiC and Mg addition. Sample 3 is a CuNi sheathed multifilamentary wire with Cu stabilization and Mg addition. All the samples with Nb barriers have the same diameter of 0.83 mm and superconducting fractions ranging from 15% to 27% of the total cross section. They were heat-treated at temperatures of 700 deg. C for a hold time of 20-40 min. Current limiting properties of MgB{sub 2} wires subjected to pulse overcurrents have been experimentally investigated in an AC environment in the self-field at 50 Hz. The quench currents extracted from the pulse measurements were in a range of 200-328 A for different samples, corresponding to an average engineering critical current density (J{sub e}) of around 4.8 x 10{sup 4} A cm{sup -2} at 25 K in the self-field, based on the 1 {mu}V cm{sup -1} criterion. This work is intended to compare the quench behaviour in the Nb-barrier monofilamentary and multifilamentary MgB{sub 2} wires with CuNi and Cu/CuNi sheaths. The experimental results can be applied to the design of fault current limiter applications based on MgB{sub 2} wires.

  10. Superconductivity of powder-in-tube MgB{sub 2} wires

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, B A; Evetts, J E [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); Department of Materials Science and Metallurgy, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Majoros, M [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); Institute of Electrical Engineering, Slovak Academy of Science, Dubravska Cesta 9, Bratislava (Slovakia); Vickers, M [Department of Materials Science and Metallurgy, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Shi, Y [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); McDougall, I [Oxford Instruments Plc, Eynsham, OX8 ITL (United Kingdom)

    2001-04-01

    A new class of 'powder-in-tube' Mg-B superconducting conductors has been prepared using two different methods: an in situ technique where an Mg + 2B mixture was used as a central conductor core and reacted in situ to form MgB{sub 2}, and an ex situ technique where fully reacted MgB{sub 2} powder was used to fill the metal tube. Conductors were prepared using silver, copper and bimetallic silver/stainless steel tubes. Wires manufactured by the in situ technique, diffusing Mg to B particles experienced {approx}25.5% decrease in density from the initial value after cold deformation, due to the phase transformation from Mg + 2({beta}-B){yields}MgB{sub 2} all with hexagonal structure. A comparative study of the intergranular current and grain connectivity in wires was conducted by AC susceptibility measurements and direct four point transport measurements. Using a SQUID magnetometer, magnetization versus magnetic field (M-H) curves of the round wires before and after sintering and reactive diffusion were measured at 5 K and in magnetic fields up to 5 T to define the J{sub cmag}. The direct current measurements were performed in self field at 4.2 K. A comparison between zero-field-cooled (ZFC) and field-cooled (FC) susceptibility measurements for sintered Ag/MgB{sub 2}, and reacted Cu/Mg + 2B conductors revealed systematic differences in the flux pinning in the wires which is in very good agreement with direct high transport current measurements. (author)

  11. Superconductivity of powder-in-tube MgB{sub 2} wires

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, B.A.; Evetts, J.E. [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); Department of Materials Science and Metallurgy, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Majoros, M. [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); Institute of Electrical Engineering, Slovak Academy of Science, Dubravska Cesta 9, Bratislava (Slovakia); Vickers, M. [Department of Materials Science and Metallurgy, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Shi, Y. [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge, CB3 OHE (United Kingdom); McDougall, I. [Oxford Instruments Plc, Eynsham, OX8 ITL (United Kingdom)

    2001-04-01

    A new class of 'powder-in-tube' Mg-B superconducting conductors has been prepared using two different methods: an in situ technique where an Mg + 2B mixture was used as a central conductor core and reacted in situ to form MgB{sub 2}, and an ex situ technique where fully reacted MgB{sub 2} powder was used to fill the metal tube. Conductors were prepared using silver, copper and bimetallic silver/stainless steel tubes. Wires manufactured by the in situ technique, diffusing Mg to B particles experienced {approx}25.5% decrease in density from the initial value after cold deformation, due to the phase transformation from Mg + 2({beta}-B){yields}MgB{sub 2} all with hexagonal structure. A comparative study of the intergranular current and grain connectivity in wires was conducted by AC susceptibility measurements and direct four point transport measurements. Using a SQUID magnetometer, magnetization versus magnetic field (M-H) curves of the round wires before and after sintering and reactive diffusion were measured at 5 K and in magnetic fields up to 5 T to define the J{sub cmag}. The direct current measurements were performed in self field at 4.2 K. A comparison between zero-field-cooled (ZFC) and field-cooled (FC) susceptibility measurements for sintered Ag/MgB{sub 2}, and reacted Cu/Mg + 2B conductors revealed systematic differences in the flux pinning in the wires which is in very good agreement with direct high transport current measurements. (author)

  12. A superconducting shield to protect astronauts

    CERN Document Server

    Antonella Del Rosso

    2015-01-01

    The CERN Superconductors team in the Technology department is involved in the European Space Radiation Superconducting Shield (SR2S) project, which aims to demonstrate the feasibility of using superconducting magnetic shielding technology to protect astronauts from cosmic radiation in the space environment. The material that will be used in the superconductor coils on which the project is working is magnesium diboride (MgB2), the same type of conductor developed in the form of wire for CERN for the LHC High Luminosity Cold Powering project.   Image: K. Anthony/CERN. Back in April 2014, the CERN Superconductors team announced a world-record current in an electrical transmission line using cables made of the MgB2 superconductor. This result proved that the technology could be used in the form of wire and could be a viable solution for both electrical transmission for accelerator technology and long-distance power transportation. Now, the MgB2 superconductor has found another application: it wi...

  13. Superconductivity: 100th anniversary of its discovery and its future

    International Nuclear Information System (INIS)

    Kitazawa, Koichi

    2011-01-01

    The past and prospects of the superconducting technology are discussed as a systematic wide technology from the aspects of energy, transport and telecommunication. Superconductivity has unique characteristics, perpetual current, diamagnetism and Josephson effect. Since its discovery 100 years ago, it had taken nearly half a century to elucidate its mechanism and its application has still been restricted only to fields of extreme needs in the technical level. The major reason for the delay has apparently been the 'penalty of cooling', however, it is also due to the fact that a superconducting wire has to be a complex composite in a nanotechnology-processed structure. Also, owing to the discovery of high-temperature superconductors, it has recently become feasible to forecast a promising future of the superconducting technology in a long term. (author)

  14. Magnetoresistance oscillations in topological insulator microwires contacted with normal and superconducting leads

    Science.gov (United States)

    Konopko, Leonid; Nikolaeva, Albina; Huber, Tito E.; Rogacki, Krzysztof

    2018-05-01

    Recent efforts to detect and manipulate Majorana fermions in solid state devices have employed topological insulator (TI) nanowires proximity coupled to superconducting (SC) leads. This combination holds some promises for the fundamental physics and applications. We studied the transverse magnetoresistance (MR) of polycrystal Bi2Te2Se and single-crystal Bi0.83Sb0.17 TI microwires contacted with superconducting In2Bi leads. Bi2Te2Se has a simple band structure with a single Dirac cone on the surface and a large non-trivial bulk gap of 300 meV. The semiconducting alloy Bi0.83Sb0.17 is a strong topological insulator due to the inversion symmetry of bulk crystalline Bi and Sb. To study the TI/SC interface, we prepared Bi2Te2Se and Bi0.83Sb0.17 glass-coated microwire samples using superconducting alloy In2Bi (Tc = 5.6 K) to provide a contact of one side of the microwires with copper leads and gallium to provide a contact of the other side of microwires with copper leads. The MR oscillations equidistant in a transverse magnetic field (up to 1 T) at the TI/SC interface were observed at various temperatures (4.2 K-1.5 K) in both the Bi2Te2Se and Bi0.83Sb0.17 samples. In the Bi2Te3 sample with a diameter of d = 17 μm, this oscillations exist with a period of ΔB = 18 mT; in the Bi0.83Sb0.17 sample with d = 1.7 μm MR oscillations are characterized by a period of ΔB = 46 mT. The observed oscillations cannot be referred to the Shubnikov de Haas oscillations because they are not periodic in an inverse magnetic field and their amplitude decreases with increasing magnetic field. Most probably, transverse MR oscillations arise owing to the appearance of highly conducting edge states on the planar boundary of SC/TI.

  15. Superconductivity revisited

    CERN Document Server

    Dougherty, Ralph

    2013-01-01

    While the macroscopic phenomenon of superconductivity is well known and in practical use worldwide in many industries, including MRIs in medical diagnostics, the current theoretical paradigm for superconductivity (BCS theory) suffers from a number of limitations, not the least of which is an adequate explanation of high temperature superconductivity. This book reviews the current theory and its limitations and suggests new ideas and approaches in addressing these issues. The central objective of the book is to develop a new, coherent, understandable theory of superconductivity directly based on molecular quantum mechanics.

  16. Feasibility study of electric motors constructed with high temperature superconducting materials

    International Nuclear Information System (INIS)

    Jordan, H.E.

    1989-01-01

    The potential application of high temperature superconducting (HTSC) materials to electric motors is discussed. The specific application area of motors in electric power generating stations has been selected and a feasible study has been initiated on the use of HTSC materials in the design of motors for this application. A progress report on this feasibility study is presented. Technical challenges in both the development of HTSC wire and the design of a motor to utilize this wire are discussed. Finally, the results of design calculations comparing a superconducting motor with one of conventional design are presented assuming that success can be achieved in overcoming the technical problems which must be resolved to produce a high performance HTSC wire

  17. Interacting loop-current model of superconducting networks

    International Nuclear Information System (INIS)

    Chi, C.C.; Santhanam, P.; Bloechl, P.E.

    1992-01-01

    The authors review their recent approximation scheme to calculate the normal-superconducting phase boundary, T c (H), of a superconducting wire network in a magnetic field in terms of interacting loop currents. The theory is based on the London approximation of the linearized Ginzburg-Landau equation. An approximate general formula is derived for any two-dimensional space-filling lattice comprising tiles of two shapes. Many examples are provided illustrating the use of this method, with a particular emphasis on the fluxoid distribution. In addition to periodic lattices, quasiperiodic lattices and fractal Sierpinski gaskets are also discussed

  18. Effect of annealing on the superconducting and normal state properties of the doped multifilamentary Cu-Nb composite wires prepared by in situ technique

    International Nuclear Information System (INIS)

    Dubey, S.S.; Dheer, P.N.

    1999-01-01

    The effect of annealing on the superconducting and normal state properties of the Ga-, In-, Ti- and Zr-doped (1 wt%) Cu-Nb composite wires prepared by in situ technique have been investigated in this paper. The wires annealed at 700 C for 10 h and then quenched at room temperature, show a decrease in the superconducting transition temperature, T c , and increase in the transition width, ΔT. Doping of the Cu-Nb wires causes an increase in the normal state resistivity and hence the upper critical field, H C2 . This results in a significant increase of J c . Annealing of these doped samples decreases H C2 and J c . In the case of In- and Ga-doped samples J c shows a marginal improvement at lower field but decreases at higher field. Zr and Ti doping appears to be beneficial for the improved J c in these in situ materials. (orig.)

  19. Lightweight MgB2 superconducting 10 MW wind generator

    International Nuclear Information System (INIS)

    Marino, I; Pujana, A; Sarmiento, G; Sanz, S; Merino, J M; Tropeano, M; Sun, J; Canosa, T

    2016-01-01

    The offshore wind market demands a higher power rate and more reliable turbines in order to optimize capital and operational costs. The state-of-the-art shows that both geared and direct-drive conventional generators are difficult to scale up to 10 MW and beyond due to their huge size and weight. Superconducting direct-drive wind generators are considered a promising solution to achieve lighter weight machines. This work presents an innovative 10 MW 8.1 rpm direct-drive partial superconducting generator using MgB 2 wire for the field coils. It has a warm iron rotor configuration with the superconducting coils working at 20 K while the rotor core and the armature are at ambient temperature. A cooling system based on cryocoolers installed in the rotor extracts the heat from the superconducting coils by conduction. The generator’s main parameters are compared against a permanent magnet reference machine, showing a significant weight and size reduction. The 10 MW superconducting generator concept will be experimentally validated with a small-scale magnetic machine, which has innovative components such as superconducting coils, modular cryostats and cooling systems, and will have similar size and characteristics as the 10 MW generator. (paper)

  20. ISTS of Fe adatoms in contact to superconducting Ta

    Energy Technology Data Exchange (ETDEWEB)

    Kamlapure, Anand; Cornils, Lasse; Wiebe, Jens; Wiesendanger, Roland [Department of Physics, Hamburg University, Hamburg (Germany); Zhou, Lihui [Department of Physics, Hamburg University, Hamburg (Germany); Max-Planck Institute for Solid State-Research, Stuttgart (Germany); Khajetoorians, Alexander A. [Department of Physics, Hamburg University, Hamburg (Germany); Institute for Molecules and Materials, Radboud University, Nijmegen (Netherlands)

    2015-07-01

    Recent local scale investigations of the competition of superconductivity and magnetism in molecular systems revealed rich physics associated with a quantum phase transition. Here, we experimentally study individual Fe atoms adsorbed on a reconstructed surface of superconducting Ta by inelastic scanning tunneling spectroscopy (ISTS) at a temperature of 1 K and as a function of magnetic field of strength up to 3 T perpendicular to the surface. We observe strong inelastic excitations at three different adsorption sites of the Fe adatoms. The majority site shows a sharp step around 2 meV which is almost independent of the magnetic field. The other two sites exhibit excitations around 1 meV and 4 meV which have a weak magnetic field dependence indicating the magnetic origin of this excitation. In all three cases the superconducting energy gap and coherence peaks are preserved at zero magnetic field indicating very weak coupling between the magnetic moment and the cooper pairs.

  1. Superconductivity in Medicine

    Science.gov (United States)

    Alonso, Jose R.; Antaya, Timothy A.

    2012-01-01

    Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

  2. An argon ion beam milling process for native AlOx layers enabling coherent superconducting contacts

    Science.gov (United States)

    Grünhaupt, Lukas; von Lüpke, Uwe; Gusenkova, Daria; Skacel, Sebastian T.; Maleeva, Nataliya; Schlör, Steffen; Bilmes, Alexander; Rotzinger, Hannes; Ustinov, Alexey V.; Weides, Martin; Pop, Ioan M.

    2017-08-01

    We present an argon ion beam milling process to remove the native oxide layer forming on aluminum thin films due to their exposure to atmosphere in between lithographic steps. Our cleaning process is readily integrable with conventional fabrication of Josephson junction quantum circuits. From measurements of the internal quality factors of superconducting microwave resonators with and without contacts, we place an upper bound on the residual resistance of an ion beam milled contact of 50 mΩ μm2 at a frequency of 4.5 GHz. Resonators for which only 6% of the total foot-print was exposed to the ion beam milling, in areas of low electric and high magnetic fields, showed quality factors above 106 in the single photon regime, and no degradation compared to single layer samples. We believe these results will enable the development of increasingly complex superconducting circuits for quantum information processing.

  3. Superconductivity in technology

    International Nuclear Information System (INIS)

    Komarek, P.

    1976-01-01

    Physics, especially high energy physics and solid state physics was the first area in which superconducting magnets were used but in the long run, the most extensive application of superconductivity will probably be in energy technology. Superconducting power transmission cables, magnets for energy conversion in superconducting electrical machines, MHD-generators and fusion reactors and magnets for energy storage are being investigated. Magnets for fusion reactors will have particularly large physical dimensions, which means that much development effort is still needed, for there is no economic alternative. Superconducting surfaces in radio frequency cavities can give Q-values up to a factor of 10 6 higher than those of conventional resonators. Particle accelerators are the important application. And for telecommunication, simple coaxial superconducting radio frequency cables seem promising. The tunnel effect in superconducting junctions is now being developed commercially for sensitive magnetometers and may soon possibly feature in the memory cells of computer devices. Hence superconductivity can play an important role in the technological world, solving physical and technological problems and showing economic advantages as compared with possible conventional techniques, bearing also in mind the importance of reliability and safety. (author)

  4. Apparatus and method to pulverize rock using a superconducting electromagnetic linear motor

    Science.gov (United States)

    Ignatiev, Alex (Inventor)

    2009-01-01

    A rock pulverizer device based on a superconducting linear motor. The superconducting electromagnetic rock pulverizer accelerates a projectile via a superconducting linear motor and directs the projectile at high speed toward a rock structure that is to be pulverized by collision of the speeding projectile with the rock structure. The rock pulverizer is comprised of a trapped field superconducting secondary magnet mounted on a movable car following a track, a wire wound series of primary magnets mounted on the track, and the complete magnet/track system mounted on a vehicle used for movement of the pulverizer through a mine as well as for momentum transfer during launch of the rock breaking projectile.

  5. Thermal analysis of the cryocooled superconducting magnet for the liquid helium-free hybrid magnet

    International Nuclear Information System (INIS)

    Ishizuka, Masayuki; Hamajima, Takataro; Itou, Tomoyuki; Sakuraba, Junji; Nishijima, Gen; Awaji, Satoshi; Watanabe, Kazuo

    2010-01-01

    The liquid helium-free hybrid magnet, which consists of an outer large bore cryocooled superconducting magnet and an inner water-cooled resistive magnet, was developed for magneto-science in high fields. The characteristic features of the cryogen-free outsert superconducting magnet are described in detail in this paper. The superconducting magnet cooled by Gifford-McMahon cryocoolers, which has a 360 mm room temperature bore in diameter, was designed to generate high magnetic fields up to 10 T. The hybrid magnet has generated the magnetic field of 27.5 T by combining 8.5 T generation of the cryogen-free superconducting magnet with 19 T generation of the water-cooled resistive magnet. The superconducting magnet was composed of inner Nb 3 Sn coils and outer NbTi coils. In particular, inner Nb 3 Sn coils were wound using high-strength CuNi-NbTi/Nb 3 Sn wires in consideration of large hoop stress. Although the cryocooled outsert superconducting magnet achieved 9.5 T, we found that the outsert magnet has a thermal problem to generate the designed maximum field of 10 T in the hybrid magnet operation. This problem is associated with unexpected AC losses in Nb 3 Sn wires.

  6. Experimentally verified inductance extraction and parameter study for superconductive integrated circuit wires crossing ground plane holes

    International Nuclear Information System (INIS)

    Fourie, Coenrad J; Wetzstein, Olaf; Kunert, Juergen; Meyer, Hans-Georg; Toepfer, Hannes

    2013-01-01

    As the complexity of rapid single flux quantum (RSFQ) circuits increases, both current and power consumption of the circuits become important design criteria. Various new concepts such as inductive biasing for energy efficient RSFQ circuits and inductively coupled RSFQ cells for current recycling have been proposed to overcome increasingly severe design problems. Both of these techniques use ground plane holes to increase the inductance or coupling factor of superconducting integrated circuit wires. New design tools are consequently required to handle the new topographies. One important issue in such circuit design is the accurate calculation of networks of inductances even in the presence of finite holes in the ground plane. We show how a fast network extraction method using InductEx, which is a pre- and post-processor for the magnetoquasistatic field solver FastHenry, is used to calculate the inductances of a set of SQUIDs (superconducting quantum interference devices) with ground plane holes of different sizes. The results are compared to measurements of physical structures fabricated with the IPHT Jena 1 kA cm −2 RSFQ niobium process to verify accuracy. We then do a parameter study and derive empirical equations for fast and useful estimation of the inductance of wires surrounded by ground plane holes. We also investigate practical circuits and show excellent accuracy. (paper)

  7. Winding workshop for the ISR low beta Superconducting Quadrupole Prototype

    CERN Multimedia

    1975-01-01

    From right to left one sees the wire spool with its electro-magnetic brake to ensure a constant tension of the superconducting wire, a pulley with a wire length recording and the winding machine. In front on the table a finished coil. In the back the heavy clamping tool. See also 7510213X, 7510213X.

  8. Transfer Efficiency and Cooling Cost by Thermal Loss based on Nitrogen Evaporation Method for Superconducting MAGLEV System

    Science.gov (United States)

    Chung, Y. D.; Kim, D. W.; Lee, C. Y.

    2017-07-01

    This paper presents the feasibility of technical fusion between wireless power transfer (WPT) and superconducting technology to improve the transfer efficiency and evaluate operating costs such as refrigerant consumption. Generally, in WPT technology, the various copper wires have been adopted. From this reason, the transfer efficiency is limited since the copper wires of Q value are intrinsically critical point. On the other hand, as superconducting wires keep larger current density and relatively higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. However, since superconducting wires should be cooled indispensably, the cooling cost of consumed refrigerant for resonance HTS wires should be estimated. In this study, the transmission ratios using HTS resonance receiver (Rx) coil and various cooled and noncooled copper resonance Rx coils were presented under non cooled copper antenna within input power of 200 W of 370 kHz respectively. In addition, authors evaluated cooling cost of liquid nitrogen for HTS resonance coil and various cooled copper resonance coils based on nitrogen evaporation method.

  9. Transfer Efficiency and Cooling Cost by Thermal Loss based on Nitrogen Evaporation Method for Superconducting MAGLEV System

    International Nuclear Information System (INIS)

    Chung, Y D; Kim, D W; Lee, C Y

    2017-01-01

    This paper presents the feasibility of technical fusion between wireless power transfer (WPT) and superconducting technology to improve the transfer efficiency and evaluate operating costs such as refrigerant consumption. Generally, in WPT technology, the various copper wires have been adopted. From this reason, the transfer efficiency is limited since the copper wires of Q value are intrinsically critical point. On the other hand, as superconducting wires keep larger current density and relatively higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. However, since superconducting wires should be cooled indispensably, the cooling cost of consumed refrigerant for resonance HTS wires should be estimated. In this study, the transmission ratios using HTS resonance receiver (Rx) coil and various cooled and noncooled copper resonance Rx coils were presented under non cooled copper antenna within input power of 200 W of 370 kHz respectively. In addition, authors evaluated cooling cost of liquid nitrogen for HTS resonance coil and various cooled copper resonance coils based on nitrogen evaporation method. (paper)

  10. 56th (fiscal 1997) Meeting on Cryogenics and Superconductivity; Dai 56 kai 1997 nendo shunki teion kogaku chodendo gakkai koen gaiyoshu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-14

    In the meeting, 266 papers were made public which deal with the following fields: GM refrigerators, pulse tube refrigerators, cold storage equipment, Bi-2212 system, coil application, superconducting generators, LHD/ITER/accelerators, cable-in conduit conductors, electromagnetic phenomena/proximity effect, oxide cable, Nb3Sn, Nb3Al, metal materials, WE-NET, friction/organic materials, composite materials, Nb3Sn, Nb3Al wires, strand wire structure analysis, hybrid superconducting wire, Y system, Bi system, low temperature device, measurement, high magnetic field NMR magnet, oxide NMR application, Bi-2223 system wire, pinning, NbTi ac wire, pinning/ac loss, various characteristics, superconducting application, refrigerating system, heat transfer, cryostat, Hg/Ti/Y system wire, ac loss/application, superconducting electric power storage system and the development of element technology therefor, current limiter/magnetic flotation, stability and drift of strand conductors, stability, ITER, LHD/accelerator/SLIM, oxide application, conductor stability test and others, and quench of ac cable.

  11. Design and market considerations for axial flux superconducting electric machine design

    Science.gov (United States)

    Ainslie, M. D.; George, A.; Shaw, R.; Dawson, L.; Winfield, A.; Steketee, M.; Stockley, S.

    2014-05-01

    In this paper, the authors investigate a number of design and market considerations for an axial flux superconducting electric machine design that uses high temperature superconductors. The axial flux machine design is assumed to utilise high temperature superconductors in both wire (stator winding) and bulk (rotor field) forms, to operate over a temperature range of 65-77 K, and to have a power output in the range from 10s of kW up to 1 MW (typical for axial flux machines), with approximately 2-3 T as the peak trapped field in the bulk superconductors. The authors firstly investigate the applicability of this type of machine as a generator in small- and medium-sized wind turbines, including the current and forecasted market and pricing for conventional turbines. Next, a study is also carried out on the machine's applicability as an in-wheel hub motor for electric vehicles. Some recommendations for future applications are made based on the outcome of these two studies. Finally, the cost of YBCO-based superconducting (2G HTS) wire is analysed with respect to competing wire technologies and compared with current conventional material costs and current wire costs for both 1G and 2G HTS are still too great to be economically feasible for such superconducting devices.

  12. Superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This book profiles the research activity of 42 companies in the superconductivity field, worldwide. It forms a unique and comprehensive directory to this emerging technology. For each research site, it details the various projects in progress, analyzes the level of activity, pinpoints applications and R and D areas, reviews strategies and provides complete contact information. It lists key individuals, offers international comparisons of government funding, reviews market forecasts and development timetables and features a bibliography of selected articles on the subject

  13. Optimization of a Superconducting Magnetic Energy Storage Device via a CPU-Efficient Semi-Analytical Simulation

    OpenAIRE

    Dimitrov, I K; Zhang, X; Solovyov, V F; Chubar, O; Li, Qiang

    2014-01-01

    Recent advances in second generation (YBCO) high temperature superconducting wire could potentially enable the design of super high performance energy storage devices that combine the high energy density of chemical storage with the high power of superconducting magnetic storage. However, the high aspect ratio and considerable filament size of these wires requires the concomitant development of dedicated optimization methods that account for both the critical current density and ac losses in ...

  14. QUANTUM ELECTRONIC DEVICES: Superconducting Nb3Sn point contact in the submillimeter range of electromagnetic radiation

    Science.gov (United States)

    Belenov, É. M.; Danileĭko, M. V.; Derkach, V. E.; Romanenko, V. I.; Uskov, A. V.

    1988-05-01

    An investigation was made of the influence of submillimeter radiation emitted by an HCN laser operating at a frequency νl = 891 GHz on a superconducting point contact made of Nb3Sn. Three steps of the electric current were recorded. The experimental results indicated that such a contact could be used for frequency multiplication up to 3 THz.

  15. Proceedings of the fourth international conference and exhibition: World Congress on superconductivity. Volume 1

    International Nuclear Information System (INIS)

    Krishen, K.; Burnham, C.

    1994-01-01

    The goals of the World Congress on Superconductivity (WCS) have been to establish and foster the development and commercial application of superconductivity technology on a global scale by providing a non-adversarial, non-advocacy forum where scientists, engineers, businessmen and government personnel can freely exchange information and ideas on recent developments and directions for the future of superconductive research. Sessions were held on: accelerator technology, power and energy, persistent magnetic fields, performance characterization, physical properties, fabrication methodology, superconductive magnetic energy storage (SMES), thin films, high temperature materials, device applications, wire fabrication, and granular superconductors. Individual papers are indexed separately

  16. Proceedings of the fourth international conference and exhibition: World Congress on superconductivity. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Krishen, K.; Burnham, C. [eds.] [National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center

    1994-12-31

    The goals of the World Congress on Superconductivity (WCS) have been to establish and foster the development and commercial application of superconductivity technology on a global scale by providing a non-adversarial, non-advocacy forum where scientists, engineers, businessmen and government personnel can freely exchange information and ideas on recent developments and directions for the future of superconductive research. Sessions were held on: accelerator technology, power and energy, persistent magnetic fields, performance characterization, physical properties, fabrication methodology, superconductive magnetic energy storage (SMES), thin films, high temperature materials, device applications, wire fabrication, and granular superconductors. Individual papers are indexed separately.

  17. Measurement of kinetic inductance of superconducting wires and application for measuring flux state of Josephson-junction loops

    Energy Technology Data Exchange (ETDEWEB)

    Shimazu, Y.; Yokoyama, T

    2004-10-01

    In order to realize strong coupling in a system of multiple flux qubits with a DC-SQUID, the use of kinetic inductance is advantageous because it can be much larger than geometrical inductance for narrow superconducting wires. We measured the inductance associated with narrow Al wires, and estimated the contributions of kinetic and geometrical inductances. The London penetration depth which determines the kinetic inductance is evaluated. We fabricated samples of two Josephson-junction loops and a DC-SQUID which are all coupled with kinetic inductances. The observed magnetic flux due to the loops is in good agreement with the result of numerical simulation based on the estimated inductances.

  18. A jelly-roll process for high temperature superconducting tapes and wires

    Energy Technology Data Exchange (ETDEWEB)

    Tsuei, C C; Chi, C C; Frey, T; Mitzi, D B; Kazyaka, T [IBM Thomas J. Watson Research Center, Yorktown Heights, NY (United States); Haugan, T; Ye, J; Patel, S; Shaw, D T [New York State Inst. on Superconductivity, SUNY, Buffalo, Amherst, NY (United States); Wu, M K [Dept. of Physics, National Tsing Hua Univ., Hsinchu (Taiwan)

    1992-07-01

    As an alternative to the powder-in-tube method, a new technique called the jelly-roll process is proposed for making high-T[sub c] superconducting tapes and wires. A normal-metal sheet coated with high-T[sub c] cuprate is configured in a jelly-roll fashion and cold worked into tapes or wires made of alternating cuprate superconductor and normal metal layers. The feasibility of this new process is demonstrated for both the YBa[sub 2]Cu[sub 3]O[sub 7]/Ag and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8]/Ag composite systems. The role of reduction in the cross-sectional area by cold-rolling, heat treatment and oxygenation in optimizing T[sub c] and J[sub c] has been studied. Preliminary results indicate that partialmelt texturing, in the Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8]/Ag system, results in a relatively field independent J[sub c] (H< or approx.7T) with J[sub c](H = 0) [proportional to]5 X 10[sup 4] A cm[sup -2] at 4.2 K.

  19. Change in properties of superconducting magnet materials by fusion neutron irradiation

    International Nuclear Information System (INIS)

    Nishimura, Arata; Nishijima, Shigehiro; Takeuchi, Takao; Nishitani, Takeo

    2007-01-01

    A fusion reactor will generate a lot of high energy neutron and much energy will be taken out of the neutrons by a blanket system. Since some neutrons will stream out of a plasma vacuum vessel through neutral beam injection ports and penetrate a blanket system, a superconducting magnet system, which provides high magnetic field to confirm high energy particles, will be irradiated by a certain amount of neutrons. By developing the new NBI system or by reducing the penetration, the neutron fluence to the superconducting magnet will be able to be reduced. However, it is not easy to achieve the lower streaming and penetration at the present. Therefore, investigations on irradiation behavior of superconducting magnet materials are desired and some novel researches have been performed from 1970s. In general, the critical current of the superconducting wire increases under fast neutron environment comparing with that of the non-irradiated wire, and then decreased to almost zero as an increase of neutron fluence. On the other hand, the critical temperature of the wire starts to get down around 10 22 n/m 2 of neutron fluence and the temperature margin will be decreased during the operation by the neutron irradiation. In this paper, some aspects of irradiated materials will be overviewed and general tendency will be discussed focussing on knock-on effect of fast neutron and long range ordering of A15 compounds

  20. Superconductivity Program for electric power systems: 1994 annual PEER review. Volume 1, Meeting proceedings

    International Nuclear Information System (INIS)

    1994-01-01

    This is Volume I of information presented at the Annual Peer Review of the Superconductivity Program For Electric Power Systems. Topics include: Wire development; powder synthesis; characterization of superconducting materials; electric power applications; magnetic refrigerators; and motor cooling issues. Individual reports were processed separately for the database

  1. Coexistence of superconductivity and superparamagnetism in Pb-Co electrodeposited nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Riminucci, Alberto [CNR-ISMN, Bologna (Italy); H.H.Wills Physics Laboratory, Bristol (United Kingdom); Schwarzacher, Walther [H.H.Wills Physics Laboratory, Bristol (United Kingdom)

    2017-03-15

    Pb-Co nanowires were electrodeposited in 100 nm nominal pore diameter polycarbonate membranes. Above the T{sub C} of Pb we modelled the behaviour of the wires with a Langevin function, obtaining a Co volume of (1.06 ± 0.01) x 10{sup -7} cm{sup 3} divided into clusters of ∼10 atoms in size. The magnetic response of the wires in the 3-10 K interval, which comprises T{sub C}, was modelled by adding spherical superconducting Pb grains to the Co clusters; the Pb grains were found to be (87 ± 6) nm in diameter. The Co clusters were not interacting and were not magnetically screened by the superconducting Pb. (orig.)

  2. Deenergizing method of superconducting magnets for Maglev in an emergency

    Energy Technology Data Exchange (ETDEWEB)

    Kishikawa, Akihiko [Railway Technical Research Inst., Tokyo (Japan); Nemoto, Kaoru [Railway Technical Research Inst., Tokyo (Japan)

    1996-12-31

    The running stability of the superconducting magnets (SCMs) mounted on the JR Maglev vehicle has been confirmed through many researches and actual running tests. So we could confirm that the high performance of our SCMs during the last few years, but we must bear in mind that the SCM which consists of the superconducting wire has the possibility of changing into normal resistive state from superconducting state. If one of the pair SCMs normalizes, a huge lateral force on one side of a bogie will occur suddenly and push the vehicle toward the sidewall of the guideway. This paper describes the method that reduces this huge force acting on one side of a bogie in an SCM accident. (orig.)

  3. Production of superconducting Nb3Sn wire using Nb or Nb(Ti) and Sn(Ga) solid solution powders

    International Nuclear Information System (INIS)

    Thieme, C.L.H.; Foner, S.

    1991-01-01

    This paper reports on superconducting Nb 3 Sn wire produced by the powder metallurgy method using Nb or Nb-2.9 at% Ti powder in combination with Sn-x at% Ga powders (x = 3, 4.2, 6.2 and 9.0). Ga additions to the Sn caused considerable solid solution hardening which improved its workability. It made the Nb-Sn(Ga) powder combinations convenient for swaging and extensive wire drawing. Anneals at 950 degrees C produced wires with an overall J c of 10 4 A/cm 2 at 21.9 T for wires with both Ti in the Nb and 6.2 at% Ga in the Sn. Comparison of this wire with the best Nb(Ti)-Cu-internal Sn(Ti) shows a higher J c per A15 areas, especially in fields of 22T and above

  4. Study on magnetic field distribution in superconducting magnetic systems with account of magnetization of a superconducting winding

    International Nuclear Information System (INIS)

    Shakhtarin, V.N.; Koshurnikov, E.K.

    1977-01-01

    A method for investigating a magnetic field in a superconducting magnetic system with an allowance for magnetization of the superconducting winding material is described. To find the field, use was made of the network method for solving a nonlinear differential equation for the scalar magnetic potential of the magnetization field with adjustment of the boundary conditions by the boundary relaxation method. It was assumed that the solenoid did not pass into the normal state, and there were no flow jumps. The calculated dependences for the magnetization field of a superconducting solenoid with an inner diameter of 43 mm, an outer diameter of 138 mm, and a winding of 159 mm length are presented. The solenoid is wound with a 37-strand niobium-titanium wire. The magnetization field gradient in the area of the geometrical centre with a magnetic field strength of 43 kOe was equal to 1 Oe/cm, this meaning that within a sphere of 1 cm radius the inhomogeneity of the magnetization field was 2.5 x 10 -5

  5. Understanding and application of superconducting materials

    International Nuclear Information System (INIS)

    Moon, Byeong Mu; Lee, Chun Heung

    1997-02-01

    This book deals with superconducting materials, which contains from basic theory to application of superconducting materials. The contents of this book are mystery of superconducting materials, properties of superconducting materials, thermodynamics of superconducting materials, theoretical background of superconducting materials, tunnelling and quantum interference, classification and properties of superconducting materials, high temperature superconducting materials, production and analysis of superconducting materials and application of superconducting materials.

  6. Superconducting Multilayer High-Density Flexible Printed Circuit Board for Very High Thermal Resistance Interconnections

    Science.gov (United States)

    de la Broïse, Xavier; Le Coguie, Alain; Sauvageot, Jean-Luc; Pigot, Claude; Coppolani, Xavier; Moreau, Vincent; d'Hollosy, Samuel; Knarosovski, Timur; Engel, Andreas

    2018-05-01

    We have successively developed two superconducting flexible PCBs for cryogenic applications. The first one is monolayer, includes 552 tracks (10 µm wide, 20 µm spacing), and receives 24 wire-bonded integrated circuits. The second one is multilayer, with one track layer between two shielding layers interconnected by microvias, includes 37 tracks, and can be interconnected at both ends by wire bonding or by connectors. The first cold measurements have been performed and show good performances. The novelty of these products is, for the first one, the association of superconducting materials with very narrow pitch and bonded integrated circuits and, for the second one, the introduction of a superconducting multilayer structure interconnected by vias which is, to our knowledge, a world-first.

  7. Superconducting energy storage magnet

    International Nuclear Information System (INIS)

    Eyssa, Y.M.; Boom, R.W.; Young, W.C.; McIntosh, G.E.; Abdelsalam, M.K.

    1986-01-01

    A superconducting magnet is described comprising: (a) a first, outer coil of one layer of conductor including at least a superconducting composite material; (b) a second, inner coil of one layer of conductor including at least a superconducting composite material. The second coil disposed adjacent to the first coil with each turn of the second inner coil at substantially the same level as a turn on the first coil; (c) an inner support structure between the first and second coils and engaged to the conductors thereof, including support rails associated with each turn of conductor in each coil and in contact therewith along its length at positions on the inwardly facing periphery of the conductor. The rail associated with each conductor is electrically isolated from other rails in the inner support structure. The magnetic field produced by a current flowing in the same direction through the conductors of the first and second coils produces a force on the conductors that are directed inwardly toward the inner support structure

  8. Submicron superconducting structures

    International Nuclear Information System (INIS)

    Golovashkin, A.I.; Lykov, A.N.

    1986-01-01

    An overview of works concerning superconducting structures of submicron dimensions and a system of such structures is given. It is noted that usage of the above structures in superconducting microelectronics permits, first, to increase the element packing density, to decrease the signal transmission time, capacity, power dissipated in high-frequency applications. Secondly, negligible coherence length in transition metals, their alloys and high-temperature compounds also restrict the dimensions of superconducting weak couplings when the 'classical' Josephson effect is displayed. The most effective methods for production of submicron superconducting structures are the following: lithography, double scribering. Recently the systems of superconducting submicron elements are extensively studied. It is shown that such systems can be phased by magnetic field

  9. Academic training: Applied superconductivity

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

  10. Superconductivity in nanowires

    CERN Document Server

    Bezryadin, Alexey

    2012-01-01

    The importance and actuality of nanotechnology is unabated and will be for years to come. A main challenge is to understand the various properties of certain nanostructures, and how to generate structures with specific properties for use in actual applications in Electrical Engineering and Medicine.One of the most important structures are nanowires, in particular superconducting ones. They are highly promising for future electronics, transporting current without resistance and at scales of a few nanometers. To fabricate wires to certain defined standards however, is a major challenge, and so i

  11. Influence of the introduction and formation of artificial pinning centers on the transport properties of nanostructured Nb{sub 3}Sn superconducting wires

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, L B S; Rodrigues, C A; Bormio-Nunes, C; Oliveira, N F Jr; Rodrigues, D Jr, E-mail: lucas_sarno@ppgem.eel.usp.b, E-mail: durval@demar.eel.usp.b [Superconductivity Group, Department of Materials Engineering (DEMAR) Escola de Engenharia de Lorena (EEL), Universidade de Sao Paulo - USP Polo Urbo-Industrial, Gleba AI-6 - PO Box 116 - Lorena, SP (Brazil)

    2009-05-01

    The formation of nanostructures projected to act as pinning centers is presented as a highly promising technique for the transport properties optimization of superconductors. However, due to the necessity of nanometric dimensions of these pinning centers, the heat treatment (HT) profiles must be carefully analyzed. The present work describes a methodology to optimize the HT profiles in respect to diffusion, reaction and formation of the superconducting phases. After the HT, samples were removed for micro structural characterization. Measurements of transport properties were performed to analyze the influence of the introduction of artificial pinning centers (APC) on the superconducting phase and to find the flux pinning mechanism acting in these wires. Fitting the volumetric pinning force vs. applied magnetic field (F{sub p} vs. mu{sub o}H) curves of transport properties, we could determine the type and influence of flux pinning mechanism acting in the global behavior of the samples. It was concluded that the maximum current densities were obtained when normal phases (due to the introduction of the APCs) are the most efficient pinning centers in the global behavior of the samples. The use of HT with profile 220{sup 0}C/100h+575{sup 0}C/50h+650{sup 0}C/100h was found as the best treatment for these nanostructured superconducting wires.

  12. Minimum Quench Energy and Early Quench Development in NbTi Superconducting Strands

    CERN Document Server

    Breschi, M; Boselli, M; Bottura, Luca; Devred, Arnaud; Ribani, P L; Trillaud, F

    2007-01-01

    The stability of superconducting wires is a crucial task in the design of safe and reliable superconducting magnets. These magnets are prone to premature quenches due to local releases of energy. In order to simulate these energy disturbances, various heater technologies have been developed, such as coated tips, graphite pastes, and inductive coils. The experiments studied in the present work have been performed using a single-mode diode laser with an optical fiber to illuminate the superconducting strand surface. Minimum quench energies and voltage traces at different magnetic flux densities and transport currents have been measured on an LHC-type, Cu/NbTi wire bathed in pool boiling helium I. This paper deals with the numerical analysis of the experimental data. In particular, a coupled electromagnetic and thermal model has been developed to study quench development and propagation, focusing on the influence of heat exchange with liquid helium.

  13. A low energy muon spin rotation and point contact tunneling study of niobium films prepared for superconducting cavities

    Science.gov (United States)

    Junginger, Tobias; Calatroni, S.; Sublet, A.; Terenziani, G.; Prokscha, T.; Salman, Z.; Suter, A.; Proslier, T.; Zasadzinski, J.

    2017-12-01

    Point contact tunneling and low energy muon spin rotation are used to probe, on the same samples, the surface superconducting properties of micrometer thick niobium films deposited onto copper substrates using different sputtering techniques: diode, dc magnetron and HIPIMS. The combined results are compared to radio-frequency tests performances of RF cavities made with the same processes. Degraded surface superconducting properties are found to correlate to lower quality factors and stronger Q-slope. In addition, both techniques find evidence for surface paramagnetism on all samples and particularly on Nb films prepared by HIPIMS.

  14. Analysis of flat rolling of superconducting silver/ceramic composites

    DEFF Research Database (Denmark)

    Bech, Jakob Ilsted; Nielsen, Morten Storgård; Eriksen, Morten

    2001-01-01

    The flat rolling process from wire to tape is presumably the most crucial link in the chain of mechanical processes leading from loose powder and silver tubes to the final superconducting Ag/BSCCO tape. In order to improve the critical current density of the superconducting filaments, one must...... process these to the highest possible density without at the same time introducing failures as large cracks and macroscopic shear bands. In order to analyse and optimise the process, the interaction between the involved materials and their very different mechanical properties must be taken into account...

  15. The state of superconductivity

    International Nuclear Information System (INIS)

    Clark, T.D.

    1981-01-01

    The present status of applications based on the phenomena of superconductivity are reviewed. Superconducting materials, large scale applications, the Josephson effect and its applications, and superconductivity in instrumentation, are considered. The influence that superconductivity has had on modern theories of elementary particles, such as gauge symmetry breaking, is discussed. (U.K.)

  16. Superconductivity - applications

    International Nuclear Information System (INIS)

    The paper deals with the following subjects: 1) Electronics and high-frequency technology, 2) Superconductors for energy technology, 3) Superconducting magnets and their applications, 4) Electric machinery, 5) Superconducting cables. (WBU) [de

  17. Basic Study of Superconductive Actuator

    OpenAIRE

    涌井, 和也; 荻原, 宏康

    2000-01-01

    There are two kinds of electromagnetic propulsion ships : a superconductive electromagnetic propulsion ship and a superconductive electricity propulsion ship. A superconductive electromagnetic propulsion ship uses the electromagnetic force (Lorenz force) by the interaction between a magnetic field and a electric current. On the other hand, a superconductive electricity propulsion ship uses screws driven by a superconductive motor. A superconductive propulsion ship technique has the merits of ...

  18. 100 years of superconductivity

    CERN Document Server

    Rogalla, Horst

    2011-01-01

    Even a hundred years after its discovery, superconductivity continues to bring us new surprises, from superconducting magnets used in MRI to quantum detectors in electronics. 100 Years of Superconductivity presents a comprehensive collection of topics on nearly all the subdisciplines of superconductivity. Tracing the historical developments in superconductivity, the book includes contributions from many pioneers who are responsible for important steps forward in the field.The text first discusses interesting stories of the discovery and gradual progress of theory and experimentation. Emphasizi

  19. The formation of Cooper pairs and the nature of superconducting currents

    International Nuclear Information System (INIS)

    Weisskopf, V.F.

    1979-12-01

    A simple physical explanation is given for the formation of Cooper pairs in a superconducting metal, for the origin of the attractive force causing the binding of the pairs, for the forming of a degenerate Bose gas by the Cooper pairs, for the finite energy gap that prevents the ensemble of electrons to change its quantum state at low temperatures, and for the existence of permanent currents in a superconducting wire. (orig.)

  20. The formation of Cooper pairs and the nature of superconducting currents

    International Nuclear Information System (INIS)

    Weisskopf, V.F.

    1981-01-01

    A simple physical explanation is given for the formation of Cooper pairs in a superconducting metal, for the origin of the attractive force causing the binding of the pairs, for the forming of a degenerate Bose gas by the Cooper pairs, for the finite energy gap that prevents the ensemble of electrons from changing its quantum state at low temperatures, and for the existence of permanent currents in a superconducting wire. (author)

  1. Superconducting current in a bisoliton superconductivity model

    International Nuclear Information System (INIS)

    Ermakov, V.N.; Kruchinin, S.P.; Ponezha, E.A.

    1991-01-01

    It is shown that the transition into a superconducting state with the current which is described by a bisoliton superconductivity model is accompanied by the deformation of the spectrum of one-particle states of the current carriers. The deformation value is proportional to the conducting current force. The residuaby resistance in such state is absent

  2. Coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compound

    International Nuclear Information System (INIS)

    Lu, T.P.; Wu, C.C.; Chou, W.H.; Lan, M.D.

    2010-01-01

    The magnetic and superconducting properties of the Sm-doped FeAs-based superconducting compound were investigated under wide ranges of temperature and magnetic field. After the systematical magnetic ion substitution, the superconducting transition temperature decreases with increasing magnetic moment. The hysteresis loop of the La 0.87-x Sm x Sr 0.13 FeAsO sample shows a superconducting hysteresis and a paramagnetic background signal. The paramagnetic signal is mainly attributed to the Sm moments. The experiment demonstrates that the coexistence of magnetism and superconductivity in the hole doped FeAs-based superconducting compounds is possible. Unlike the electron doped FeAs-based superconducting compounds SmFeAsOF, the hole doped superconductivity is degraded by the substitution of La by Sm. The hole-doped and electron-doped sides are not symmetric.

  3. Local switching of two-dimensional superconductivity using the ferroelectric field effect

    Science.gov (United States)

    Takahashi, K. S.; Gabay, M.; Jaccard, D.; Shibuya, K.; Ohnishi, T.; Lippmaa, M.; Triscone, J.-M.

    2006-05-01

    Correlated oxides display a variety of extraordinary physical properties including high-temperature superconductivity and colossal magnetoresistance. In these materials, strong electronic correlations often lead to competing ground states that are sensitive to many parameters-in particular the doping level-so that complex phase diagrams are observed. A flexible way to explore the role of doping is to tune the electron or hole concentration with electric fields, as is done in standard semiconductor field effect transistors. Here we demonstrate a model oxide system based on high-quality heterostructures in which the ferroelectric field effect approach can be studied. We use a single-crystal film of the perovskite superconductor Nb-doped SrTiO3 as the superconducting channel and ferroelectric Pb(Zr,Ti)O3 as the gate oxide. Atomic force microscopy is used to locally reverse the ferroelectric polarization, thus inducing large resistivity and carrier modulations, resulting in a clear shift in the superconducting critical temperature. Field-induced switching from the normal state to the (zero resistance) superconducting state was achieved at a well-defined temperature. This unique system could lead to a field of research in which devices are realized by locally defining in the same material superconducting and normal regions with `perfect' interfaces, the interface being purely electronic. Using this approach, one could potentially design one-dimensional superconducting wires, superconducting rings and junctions, superconducting quantum interference devices (SQUIDs) or arrays of pinning centres.

  4. Effect of Sintering Time and Diameter on Bi-Pb-Sr-Ca-Cu-O Superconducting Wire Formation with TiO2 Dopant by Silver (Ag Tube

    Directory of Open Access Journals (Sweden)

    Cindy Al Kindi

    2018-01-01

    Full Text Available Pengaruh waktu sintering dan diameter terhadap pembentukan kawat superkonduktor Bi-Pb-Sr-Ca-Cu-O dengan dopan TiO2 menggunakan tabung perak (Ag menjadi penting untuk dibahas karena hal ini berpengaruh terhadap adanya suhu kritis yang merupakan syarat penting superkonduktor. Pada penelitian ini ada beberapa tahap yang dilakukan yaitu preparasi bahan, proses permesinan, penarikan kawat dan proses perlakuan panas. Serbuk BPSCCO dengan dopan TiO2 dimasukkan ke dalam tabung perak (Ag dan dikalsinasi pada temperatur 820oC selama 20 jam, lalu proses penarikan (Rolling sampai diameter 6 mm dan 2,6 mm serta sintering dilakukan pada temperatur 850oC selama 9 jam dan 30 jam untuk masing-masing ukuran diameter dengan dua kali proses sintering. Hasil penelitian menunjukkan bahwa kawat superkonduktor memiliki suhu kritis yaitu Tc onset = 99 K dan Tc zero = 70 K. Waktu yang sangat berpengaruh pada pembentukan fasa superkonduktor yaitu sintering selama 9 jam sedangkan untuk ukuran diameter kawat yang memiliki suhu kritis yaitu 6 mm, sedangkan waktu sintering selama 30 jam dapat merubah fasa BPSCCO sehingga tidak terbentuk superkonduktor melainkan konduktor dan semikonduktor. Pada diameter 2,6 mm belum menjadi ukuran yang tepat pada pembentukan kawat superkonduktor.   The influence of sintering time and diameter on the formation of Bi-Pb-Sr-Ca-Cu-O superconducting wire with doped TiO2 by silver (Ag tube becomes important to be discussed because of the presence of critical temperature which is an essential condition in superconductors. In this research there are several steps must be done that is: material preparation, machine process, wire drawing and heat process. BPSCCO powder with dopant TiO2 filled into silver (Ag tube with calcination temperature at 820oC for 20 h, then rolling process to diameter 6 mm and 2,6 mm with sintering temperature at 850oC for 9 h and 30 h for each size of diameter by twice sintering process. The results showed that

  5. Analysis of reflection-coefficient by wireless power transmission using superconducting coils

    International Nuclear Information System (INIS)

    Jeong, In Sung; Choi, Hyo Sang; Chung, Dong Chul

    2017-01-01

    The use of electronic devices such as mobile phones and tablet PCs has increased of late. However, the power which is supplied through wires has a limitation of the free use of devices and portability. Magnetic-resonance wireless power transfer (WPT) can achieve increased transfer distance and efficiency compared to the existing electromagnetic inductive coupling. A superconducting coil can be applied to increase the efficiency and distance of magnetic-resonance WPT. As superconducting coils have lower resistance than copper coils, they can increase the quality factor (Q-factor) and can overcome the limitations of magnetic-resonance WPT. In this study, copper coils were made from ordinary copper under the same condition as the superconducting coils for a comparison experiment. Superconducting coils use liquid nitrogen to keep the critical temperature. As there is a difference of medium between liquid nitrogen and air, liquid nitrogen was also used in the normal conductor coil to compare the experiment with under the same condition. It was confirmed that superconducting coils have a lower reflection-coefficient(S11) than the normal conductor coils

  6. Analysis of reflection-coefficient by wireless power transmission using superconducting coils

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, In Sung; Choi, Hyo Sang [Chosun University, Gwangju (Korea, Republic of); Chung, Dong Chul [Korea Institute of Carbon Convergence Technology, Jeonju (Korea, Republic of)

    2017-06-15

    The use of electronic devices such as mobile phones and tablet PCs has increased of late. However, the power which is supplied through wires has a limitation of the free use of devices and portability. Magnetic-resonance wireless power transfer (WPT) can achieve increased transfer distance and efficiency compared to the existing electromagnetic inductive coupling. A superconducting coil can be applied to increase the efficiency and distance of magnetic-resonance WPT. As superconducting coils have lower resistance than copper coils, they can increase the quality factor (Q-factor) and can overcome the limitations of magnetic-resonance WPT. In this study, copper coils were made from ordinary copper under the same condition as the superconducting coils for a comparison experiment. Superconducting coils use liquid nitrogen to keep the critical temperature. As there is a difference of medium between liquid nitrogen and air, liquid nitrogen was also used in the normal conductor coil to compare the experiment with under the same condition. It was confirmed that superconducting coils have a lower reflection-coefficient(S11) than the normal conductor coils.

  7. Superconducting pulsed magnets

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mechanisms and calculation of total losses in the magnet. The need for cooling to minimize temperature rise in a magnet. Measuring ac losses in wires and in magnets. Lecture 5. Stab...

  8. Status and prospects on development of yttrium-based high-temperature superconducting coated conductor

    International Nuclear Information System (INIS)

    Izumi, Teruo; Yanagi, Nagato

    2017-01-01

    Development of a large-sized large-current conductor using a high-temperature superconducting wire rod based on copper oxide has been started worldwide for the purpose of applying it as an option of a magnet for a nuclear fusion prototype reactor. There is yttrium-based thin film wire rod as a promising candidate. Japan is leading the development of this wire rod for many years, aiming to apply it to power equipment and the like. This paper explained the history of wire rod development, basic superconducting properties and manufacturing method, and latest achievements, and overviewed the feasibility of application to nuclear fusion reactor magnets. At present, the use of niobium-based low-temperature superconducting wire rod that is used in ITER is the basic idea. On the other hand, the development of wire rod using a copper oxide type high-temperature superconductor (HTS) has also been started. HTS wire rod is evaluated as suitable for application to nuclear fusion magnets due to its superior critical current characteristics and high mechanical rigidity up to high magnetic fields at high temperatures of yttrium. As current development progress, there are development of high-quality wire rod in the magnetic field and development of low AC loss wire rod. As future prospects, cost reduction due to mass production and improvement of yield, and investigation of low-resistance connection technology are being studied. The remaining future challenges of yttrium-based HTS are improvement of the anisotropy, influence on neutron irradiation, and problem of activation. (A.O.)

  9. Overview of Superconductivity and Challenges in Applications

    Science.gov (United States)

    Flükiger, Rene

    2012-01-01

    Considerable progress has been achieved during the last few decades in the various fields of applied superconductivity, while the related low temperature technology has reached a high level. Magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) are so far the most successful applications, with tens of thousands of units worldwide, but high potential can also be recognized in the energy sector, with high energy cables, transformers, motors, generators for wind turbines, fault current limiters and devices for magnetic energy storage. A large number of magnet and cable prototypes have been constructed, showing in all cases high reliability. Large projects involving the construction of magnets, solenoids as well as dipoles and quadrupoles are described in the present book. A very large project, the LHC, is currently in operation, demonstrating that superconductivity is a reliable technology, even in a device of unprecedented high complexity. A project of similar complexity is ITER, a fusion device that is presently under construction. This article starts with a brief historical introduction to superconductivity as a phenomenon, and some fundamental properties necessary for the understanding of the technical behavior of superconductors are described. The introduction of superconductivity in the industrial cycle faces many challenges, first for the properties of the base elements, e.g. the wires, tapes and thin films, then for the various applied devices, where a number of new difficulties had to be resolved. A variety of industrial applications in energy, medicine and communications are briefly presented, showing how superconductivity is now entering the market.

  10. High-current applications of superconductivity

    International Nuclear Information System (INIS)

    Komarek, P.

    1995-01-01

    The following topics were dealt with: superconducting materials, design principles of superconducting magnets, magnets for research and engineering, superconductivity for power engineering, superconductivity in nuclear fusion technology, economical considerations

  11. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  12. Superconducting linac

    International Nuclear Information System (INIS)

    Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

    1978-01-01

    This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

  13. Superconductivity and electron microscopy

    International Nuclear Information System (INIS)

    Hawkes, P.W.; Valdre, U.

    1977-01-01

    In this review article, two aspects of the role of superconductivity in electron microscopy are examined: (i) the development of superconducting devices (mainly lenses) and their incorporation in electron microscopes; (ii) the development of electron microscope techniques for studying fundamental and technological problems associated with superconductivity. The first part opens with a brief account of the relevant properties of conventional lenses, after which the various types of superconducting lenses are described and their properties compared. The relative merits and inconveniences of superconducting and conventional lenses are examined, particular attention being paid to the spherical and chromatic aberration coefficients at accelerating voltages above a megavolt. This part closes with a survey of the various microscope designs that have been built or proposed, incorporating superconducting components. In the second part, some methods that have been or might be used in the study of superconductivity in the electron microscope are described. A brief account of the types of application for which they are suitable is given. (author)

  14. Superconductivity in transition metals.

    Science.gov (United States)

    Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

    2015-03-13

    A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  15. Development of Experimental Superconducting Magnet for the Collector Ring of FAIR Project

    International Nuclear Information System (INIS)

    Zhu Yinfeng; Wu Weiyue; Wu Songtao; Liu Changle; Xu Houchang

    2010-01-01

    A pool cooled experimental magnet based on the copper stabilized NbTi superconducting wire was designed, fabricated and tested, in order to evaluate the engineering design of the dipole superconducting magnet for the collector ring (CR) of the facility for antiproton and ion research (FAIR) project. In this paper, the experimental setup including quench protection system was presented. Performance of the liquid helium pool cooled test was introduced. All of the results indicate both the performance of conductor and the experimental superconducting magnet under low temperature is stable, which suggests the engineering design are feasible for the formal magnet in CR of the FAIR project.

  16. Linear arrangement of metallic and superconducting defects in a thin superconducting sample

    International Nuclear Information System (INIS)

    Barba-Ortega, J.; Sardella, Edson; Albino Aguiar, J.

    2013-01-01

    Highlights: • We study the influence of superconducting and metallic defects on the vortex configurations in a thin mesoscopic disk. • We found that the vortex–defect interaction leads to interesting vortex configurations. • The first vortex entry is always (never) found sitting on the metallic (superconducting) defect position. -- Abstract: The vortex matter in a superconducting disk with a linear configuration of metallic and superconducting defects is studied. Effects associated to the pinning (anti-pinning) force of the metallic (superconducting) defect on the vortex configuration and on the thermodynamic critical fields are analyzed in the framework of the Ginzburg Landau theory. We calculate the loop of the magnetization, vorticity and free energy curves as a function of the magnetic field for a thin disk. Due to vortex–defect attraction for a metallic defect (repulsion for a superconducting defect), the vortices always (never) are found to be sitting on the defect position

  17. Superconducting state mechanisms and properties

    CERN Document Server

    Kresin, Vladimir Z; Wolf, Stuart A

    2014-01-01

    'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

  18. Preparation of YBaCuO superconducting tape by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Fukutomi, Masao; Akutsu, Nakao; Tanaka, Yoshiaki; Asano, Toshihisa; Maeda, Hiroshi (National Research Inst. for Metals, Tsukuba (Japan); Mitsui Mining and Smelting Co., Ltd., Tokyo (Japan))

    1989-04-01

    The effect of buffer layers, conditions of film preparation, and the relation between superconducting characteristics and bombardment of high energy ions on films were discussed in an attempt to fabricate YBaCuO films on metallic substrates by sputtering. Hastelloy-X tapes and Chromel (Ni-10Cr) fine wires were used as metallic substrates, and MgO films as buffer layers, which were provided by sputtering a MgO sintered target and annealing. As a result, superconducting films were favorably obtained on the Hastelloy tapes with the MgO buffer layers, however, counter diffusion at the interface of the film and layer was unavoidable in annealing. C axis-highly oriented film with high zero resistance Tc was obtained in such an arrangement of the target and substrate as to lower the effect of 0{sup {minus}} ion resputtering, resulting in the most favorable Tc=80.4K. YBaCuO superconducting films could be also deposited on a bundle of Chromel fine wires preliminarily. 11 refs., 7 figs.

  19. Enhanced superconductivity of fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Washington, II, Aaron L.; Teprovich, Joseph A.; Zidan, Ragaiy

    2017-06-20

    Methods for enhancing characteristics of superconductive fullerenes and devices incorporating the fullerenes are disclosed. Enhancements can include increase in the critical transition temperature at a constant magnetic field; the existence of a superconducting hysteresis over a changing magnetic field; a decrease in the stabilizing magnetic field required for the onset of superconductivity; and/or an increase in the stability of superconductivity over a large magnetic field. The enhancements can be brought about by transmitting electromagnetic radiation to the superconductive fullerene such that the electromagnetic radiation impinges on the fullerene with an energy that is greater than the band gap of the fullerene.

  20. Superconducting ac cable

    Science.gov (United States)

    Schmidt, F.

    1980-11-01

    The components of a superconducting 110 kV ac cable for power ratings or = 2000 MVA were developed. The cable design is of the semiflexible type, with a rigid cryogenic envelope containing a flexible hollow coaxial cable core. The cable core consists of spirally wound Nb-A1 composite wires electrically insulated by high pressure polyethylene tape wrappings. A 35 m long single phase test cable with full load terminals rated at 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of this cable design.

  1. Superconducting ac cable

    International Nuclear Information System (INIS)

    Schmidt, F.

    1980-01-01

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.) [de

  2. Superconducting Material - A study on the near field of a superconducting antenna

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soon Chil; Lee, Seung Chul; Doe, Joong Hoe; Hoe, Mi Ra [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-01

    The pulse spectroscopy in combination with piezoelectric resonance makes an ideal non-disturbing tool for the measurement of electric field near an antenna. This new field sensing technique was used to investigate the field of a ring antenna the near field of which is widely used such as the plasma generation and NMR. The superconducting wire also have the dominant capacitive AC field in near regions, meaning that the net charge on the ring surface is not due to the ohm`s law as in DC. 23 refs., 8 figs. (author)

  3. Hole superconductivity

    International Nuclear Information System (INIS)

    Hirsch, J.E.; Marsiglio, F.

    1989-01-01

    The authors review recent work on a mechanism proposed to explain high T c superconductivity in oxides as well as superconductivity of conventional materials. It is based on pairing of hole carriers through their direct Coulomb interaction, and gives rise to superconductivity because of the momentum dependence of the repulsive interaction in the solid state environment. In the regime of parameters appropriate for high T c oxides this mechanism leads to characteristic signatures that should be experimentally verifiable. In the regime of conventional superconductors most of these signatures become unobservable, but the characteristic dependence of T c on band filling survives. New features discussed her include the demonstration that superconductivity can result from repulsive interactions even if the gap function does not change sign and the inclusion of a self-energy correction to the hole propagator that reduces the range of band filling where T c is not zero

  4. Emergent Higgsless Superconductivity

    Directory of Open Access Journals (Sweden)

    Cristina Diamantini M.

    2017-01-01

    Full Text Available We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D-1-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact lowenergy effective BF theories. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2 and the topological order (4 are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D thi! s type of superconductivity is explicitly realized as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

  5. Superconducting Fullerene Nanowhiskers

    Directory of Open Access Journals (Sweden)

    Yoshihiko Takano

    2012-04-01

    Full Text Available We synthesized superconducting fullerene nanowhiskers (C60NWs by potassium (K intercalation. They showed large superconducting volume fractions, as high as 80%. The superconducting transition temperature at 17 K was independent of the K content (x in the range between 1.6 and 6.0 in K-doped C60 nanowhiskers (KxC60NWs, while the superconducting volume fractions changed with x. The highest shielding fraction of a full shielding volume was observed in the material of K3.3C60NW by heating at 200 °C. On the other hand, that of a K-doped fullerene (K-C60 crystal was less than 1%. We report the superconducting behaviors of our newly synthesized KxC60NWs in comparison to those of KxC60 crystals, which show superconductivity at 19 K in K3C60. The lattice structures are also discussed, based on the x-ray diffraction (XRD analyses.

  6. Development of partially-stabilized pulsed superconducting magnets

    International Nuclear Information System (INIS)

    Tateishi, Hiroshi; Onishi, Toshitada; Komuro, Kazuo; Koyama, Kenichi

    1987-01-01

    Two types of pulsed superconducting cables and four pulsed superconducting magnets have been developed in order to investigate basic problems in constructing ohmic heating coils of a tokamak-type fusion reactor. We found that a compacted cable is superior in mechanical rigidity and a braided cable is superior in cooling capacity as a conductor of a pulsed magnet. Stored energy and a maximum field of the magnets are 78 kJ and 6 T, 68 kJ and 4 T, 375 kJ and 6 T, and 363 kJ and 3 T, respectively. Some of these magnets quenched in pulsive operations due to excessive ac losses or macroscopic wire motions. Therefore, main conditions for operating pulsed magnets without quenching are (1) to make ac losses low enough to be cooled with liquid helium existing near at the conductor surface by reducing filament diameter to the order of 10 μm and utilizing CuNi as matrix effectively, and (2) to prevent macroscopic wire motions by partial solderfilling of a cable or winding a magnet with strong tension. (author)

  7. Superconducting quantum electronics

    International Nuclear Information System (INIS)

    Kose, V.

    1989-01-01

    This book reviews recent accomplishments, presents new results and discusses possible future developments of superconducting quantum electronics and high T c superconductivity. The three main parts of the book deal with fundamentals, sensitive detectors, and precision metrology. New results reported include: correct equivalent circuits modelling superconducting electronic devices; exact solution of the Mattis-Bardeen equations describing various experiments for thin films; complete theoretical description and experimental results for a new broad band spectrum analyzer; a new Josephson junction potentiometer allowing tracing of unknown voltage ratios back to well-known frequency ratios; and fast superconducting SQUID shift registers enabling the production of calculable noise power spectra in the microwave region

  8. Electromagnetic forces on type-II superconducting rotating cylinders

    International Nuclear Information System (INIS)

    Saif, A.G.; Refai, T.F.; El-Sabagh, M.A.

    1995-01-01

    Analytical solutions of the electromagnetic fields are presented for a system composed of an infinitely long superconducting cylinder rotating about its axis and placed parallel to two infinitely long normal conducting wires. Both wires carry the same alternating current. From the obtained electromagnetic fields the electromagnetic power loss on the cylinder surface, electromagnetic forces due to induced currents, electromagnetic torque, and the work opposing the rotation of the cylinder are calculated. (orig.)

  9. High-Density Superconducting Cables for Advanced ACTPol

    Science.gov (United States)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; McMahon, J.; Nati, F.; Niemack, M. D.; Niraula, P.; Salatino, M.; Schillaci, A.; Schmitt, B. L.; Simon, S. M.; Staggs, S. T.; Stevens, J. R.; Vavagiakis, E. M.; Ward, J. T.; Wollack, E. J.

    2016-07-01

    Advanced ACTPol (AdvACT) is an upcoming Atacama Cosmology Telescope (ACT) receiver upgrade, scheduled to deploy in 2016, that will allow measurement of the cosmic microwave background polarization and temperature to the highest precision yet with ACT. The AdvACT increase in sensitivity is partly provided by an increase in the number of transition-edge sensors (TESes) per array by up to a factor of two over the current ACTPol receiver detector arrays. The high-density AdvACT TES arrays require 70 \\upmu m pitch superconducting flexible cables (flex) to connect the detector wafer to the first-stage readout electronics. Here, we present the flex fabrication process and test results. For the flex wiring layer, we use a 400-nm-thick sputtered aluminum film. In the center of the cable, the wiring is supported by a polyimide substrate, which smoothly transitions to a bare (uncoated with polyimide) silicon substrate at the ends of the cable for a robust wedge wire-bonding interface. Tests on the first batch of flex made for the first AdvACT array show that the flex will meet the requirements for AdvACT, with a superconducting critical current above 1 mA at 500 mK, resilience to mechanical and cryogenic stress, and a room temperature yield of 97 %.

  10. ORNL superconducting technology program for electric energy systems

    Science.gov (United States)

    Hawsey, R. A.

    1993-02-01

    The Oak Ridge National Laboratory (ORNL) Superconducting Technology Program is conducted as part of a national effort by the US Department of Energy's (DOE's) Office of Conservation and Renewable Energy to develop the technology base needed by US industry for commercial development of electric power applications of high-temperature superconductivity. The two major elements of this program are wire development and systems development. This document describes the major research and development activities for this program together with related accomplishments. The technical progress reported was summarized from information prepared for the FY-92 Peer Review of Projects, which was conducted by DOE's Office of Program Analysis, Office of Energy Research. This ORNL program is highly leveraged by the staff and other resources of US industry and universities. Interlaboratory teams are also in place on a number of industry-driven projects. Patent disclosures, working group meetings, staff exchanges, and joint publications and presentations ensure that there is technology transfer to US industry. Working together, the collaborative teams are making tremendous progress in solving the scientific and technical issues necessary for the commercialization of long lengths of practical high-temperature superconductor wire and wire products.

  11. Superconductivity in graphite intercalation compounds

    International Nuclear Information System (INIS)

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P.M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-01-01

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC 6 and YbC 6 in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition

  12. Superconductivity in graphite intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

    2015-07-15

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  13. Realisation and instrumentation of high current power station for superconducting cables testing

    International Nuclear Information System (INIS)

    Regnaud, S.

    2000-05-01

    This report deals with the designing of a high current station able to test electric properties of superconductors. This test station will be used for testing the superconducting wires of large hadron collider detectors in CERN. The high current test station will have to generate high intensity continuous current in a magnetic field of 0 to 5 tesla and in temperature conditions of 4.2 K. The length of wire samples submitted to the uniform magnetic field is 300 mm and the installation is fitted with equipment able to measure the magnetic field perpendicular to either faces of the wire. The peculiarity of this station is to use a superconducting transformer in order to generate the high current. The first part of this work recalls important notions concerning superconductivity. The second part presents the high current station by describing the superconducting transformer and the sample-holder. We have studied the designing of a transformer able to yield a secondary current whose intensity reaches 100 kA, such intensity generates powerful electromagnetic forces (566 kN/m) in case of defect, so the sample-holder has to be carefully design to bear them. The third part presents the cryogenic component of the station, the instrumentation of the sample-holder and the method used to measure secondary currents. In the last part we present the performance of a prototype transformer, this prototype is able to deliver a 22 kA secondary current for a 160 A primary current, the uncertainty on the measured value of the secondary current is about 3%

  14. Modern high-temperature superconductivity

    International Nuclear Information System (INIS)

    Ching Wu Chu

    1988-01-01

    Ever since the discovery of superconductivity in 1911, its unusual scientific challenge and great technological potential have been recognized. For the past three-quarters of a century, superconductivity has done well on the science front. This is because sueprconductivity is interesting not only just in its own right but also in its ability to act as a probe to many exciting nonsuperconducting phenomena. For instance, it has continued to provide bases for vigorous activities in condensed matter science. Among the more recent examples are heavy-fermion systems and organic superconductors. During this same period of time, superconductivity has also performed admirably in the applied area. Many ideas have been conceived and tested, making use of the unique characteristics of superconductivity - zero resistivity, quantum interference phenomena, and the Meissner effect. In fact, it was not until late January 1987 that it became possible to achieve superconductivity with the mere use of liquid nitrogen - which is plentiful, cheap, efficient, and easy to handle - following the discovery of supercondictivity above 90 K in Y-Ba-Cu-O, the first genuine quaternary superconductor. Superconductivity above 90 K poses scientific and technological challenges not previously encountered: no existing theories can adequately describe superconductivity above 40 K and no known techniques can economically process the materials for full-scale applications. In this paper, therefore, the author recalls a few events leading to the discovery of the new class of quaternary compounds with a superconducting transition temperature T c in the 90 K range, describes the current experimental status of high-temperature superconductivity and, finally, discusses the prospect of very-high-temperature superconductivity, i.e., with a T c substantially higher than 100 K. 97 refs., 7 figs

  15. Overview of superconductivity in Japan Strategy road map and R&D status

    Science.gov (United States)

    Tsukamoto, O.

    2008-09-01

    Superconducting technology benefits society in broad fields; environment/energy, life science, manufacturing industry and information and communication. Superconducting equipments and devices used in various fields are divided into two categories, electric and electronic applications. Technologies in those applications are progressing remarkably owing to firm and consistent supports by various national projects. The final target of the NEDO R&D project of fundamental technology for superconductivity applications to develop 500 m long coated conductors (CCs) of the critical current 300 A/cm (at 77 K, 0 T) will be fulfilled by the end of JFY 2007 and manufacturing process to produce extremely low-cost CCs is to be developed to make the applications realistic. Preliminary works to develop power apparatuses using CCs have started in the frame of the R&D project for the fundamental technology and have produced significant results. Performance of BSCCO/Ag-sheathed wires has been improved greatly and various applications using those wires are being developed. R&D projects for SMES, power cable, flywheel energy storage and rotating machines are going to introduce those equipments to the real world. Technologies of SQUID and SFQ, basic devices of the electronic applications, are progressing dramatically also owing to various national projects. In this back ground the technology strategy map in the field of superconducting technology was formulated to prioritize investments in R&D by clearly defining the objectives and inspire autonomous R&D actives in various fields of industries. R&D activities in the superconducting technologies are to be scheduled following this strategy map.

  16. Inhomogeneous superconductivity in a ferromagnet

    International Nuclear Information System (INIS)

    Kontos, T.; Aprili, M.; Lesueur, J.; Genet, F.; Boursier, R.; Grison, X.

    2003-01-01

    We have studied a new superconducting state where the condensate wave function resulting from conventional pairing, is modified by an exchange field. Superconductivity is induced into a ferromagnetic thin film (F) by the proximity effect with a superconducting reservoir (S). We observed oscillations of the superconducting order parameter induced in F as a function of the distance from the S/F interface. They originate from the finite momentum transfer provided to Cooper pairs by the splitting of the spin up and down bands. We measured the superconducting density of states in F by tunneling spectroscopy and the Josephson critical current when F is coupled with a superconducting counter-electrode. Negative values of the superconducting order parameter are revealed by capsized tunneling spectra in F and a negative Josephson coupling (π-junction)

  17. Method and etchant to join Ag-clad BSSCO superconducting tape

    Science.gov (United States)

    Balachandran, U.; Iyer, A.N.; Huang, J.Y.

    1999-03-16

    A method of removing a silver cladding from high temperature superconducting material clad in silver (HTS) is disclosed. The silver clad HTS is contacted with an aqueous solution of HNO{sub 3} followed by an aqueous solution of NH{sub 4}OH and H{sub 2}O{sub 2} for a time sufficient to remove the silver cladding from the superconducting material without adversely affecting the superconducting properties of the superconducting material. A portion of the silver cladding may be masked with a material chemically impervious to HNO{sub 3} and to a combination of NH{sub 4}OH and H{sub 2}O{sub 2} to preserve the Ag coating. A silver clad superconductor is disclosed, made in accordance with the method discussed. 3 figs.

  18. Lightweight superconducting magnet for a test facility of magnetic suspension for vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, S; Fujino, H; Onodera, K; Hirai, K

    1973-01-01

    Light weight superconducting magnets are required in the magnetic suspension of high speed trains. A ring shaped magnet consisting of two C-shaped superconducting coils was manufactured and tested. Twisted multifilament Nb-TI wires were used for the superconducting coils and the concept of the pipe structure for a cryostat was adopted. These improved the reliability and reduced the weight. In order to minimize the amount of heat leak into the cryostat, and FRP support with a hinge structure was used against the lift force. The superconducting coil generates a magnetomotive force of 200 kAT at a rated current of 855 A and the dimensions and weight of the whole unit are 1540 mm (outer diameter) and 560 mm (height), and 650 kG, respectively. The suspension test was done in the persistent current mode. The suspension height of 80 mm was observed at an exciting current of 800 A.

  19. Point-contact spectroscopic studies on normal and superconducting AFe2As2-type iron pnictide single crystals

    International Nuclear Information System (INIS)

    Lu Xin; Park, W K; Greene, L H; Yuan, H Q; Chen, G F; Luo, G L; Wang, N L; Sefat, A S; McGuire, M A; Jin, R; Sales, B C; Mandrus, D; Gillett, J; Sebastian, Suchitra E

    2010-01-01

    Point-contact Andreev reflection spectroscopy is applied to investigate the gap structure in iron pnictide single-crystal superconductors of the AFe 2 As 2 (A = Ba, Sr) family ('Fe-122'). The observed point-contact junction conductance curves, G(V), can be divided into two categories: one where Andreev reflection is present for both (Ba 0.6 K 0.4 )Fe 2 As 2 and Ba(Fe 0.9 Co 0.1 ) 2 As 2 , and the other with a V 2/3 background conductance universally observed, extending even up to 100 meV for Sr 0.6 Na 0.4 Fe 2 As 2 and Sr(Fe 0.9 Co 0.1 ) 2 As 2 . The latter is also observed in point-contact junctions on the nonsuperconducting parent compound BaFe 2 As 2 and superconducting (Ba 0.6 K 0.4 )Fe 2 As 2 crystals. Mesoscopic phase-separated coexistence of magnetic and superconducting orders is considered to explain distinct behaviors in the superconducting samples. For Ba 0.6 K 0.4 Fe 2 As 2 , double peaks due to Andreev reflection with a strongly sloping background are frequently observed for point contacts on freshly cleaved c-axis surfaces. If normalized using a background baseline and analyzed using the Blonder-Tinkham-Klapwijk model, the data show a gap size of ∼ 3.0-4.0 meV with 2Δ 0 /k B T c ∼ 2.0-2.6, consistent with the smaller gap size reported for the LnFeAsO family ('Fe-1111'). For the Ba(Fe 0.9 Co 0.1 ) 2 As 2 , the G(V) curves typically display a zero-bias conductance peak.

  20. WORKSHOP: Radiofrequency superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-10-15

    The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators.

  1. WORKSHOP: Radiofrequency superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The Second Workshop on Radiofrequency Superconductivity was held at CERN from 23-27 July, four years after the first, organized at Karlsruhe. 35 invited talks were presented to the about 80 participants from Australia, Brazil, Europe, Japan and the United States. For the first time, ten Laboratories operating or planning superconducting accelerators for heavy ions participated and shared their experience with the community proposing the use of superconducting accelerating sections for electron accelerators

  2. A new structure of superconducting magnetic system for 50 GHz operations (invited).

    Science.gov (United States)

    Xie, D Z

    2012-02-01

    High field and high frequency have been leading the development of electron cyclotron resonance ion sources (ECRISs) in the past decade as demonstrated by the achieved great performance. The present superconducting magnet structures built with NbTi wires have reached an axial field of 3.5-4.0 T and a radial field of 2.0 T for operating frequency up to 28 GHz. Further increase of the magnetic field strength will require higher current superconductor, i.e., Nb(3)Sn wires. This paper will present the features of a new superconducting magnet structure and review of the existing structures. Using NbTi wires, the new magnet structure could be able to produce maximum fields of 7.0 T on axis and radial field of 3.7 T at a hexagonal plasma chamber wall for ECRIS operations up to 50 GHz. If this new magnet can be built with Nb(3)Sn wires, much higher fields can be expected.

  3. Organic superconductivity

    International Nuclear Information System (INIS)

    Jerome, D.

    1980-01-01

    We present the experimental evidences for the existence of a superconducting state in the Quasi One Dimensional organic conductor (TMTSF) 2 PF 6 . Superconductivity occuring at 1 K under 12 kbar is characterized by a zero resistance diamagnetic state. The anistropy of the upper critical field of this type II superconductor is consistent with the band structure anistropy. We present evidences for the existence of large superconducting precursor effects giving rise to a dominant paraconductive contribution below 40 K. We also discuss the anomalously large pressure dependence of T sb(s), which drops to 0.19 K under 24 kbar in terms of the current theories. (author)

  4. Superconducting nanostructured materials

    International Nuclear Information System (INIS)

    Metlushko, V.

    1998-01-01

    Within the last year it has been realized that the remarkable properties of superconducting thin films containing a periodic array of defects (such as sub-micron sized holes) offer a new route for developing a novel superconducting materials based on precise control of microstructure by modern photolithography. A superconductor is a material which, when cooled below a certain temperature, loses all resistance to electricity. This means that superconducting materials can carry large electrical currents without any energy loss--but there are limits to how much current can flow before superconductivity is destroyed. The current at which superconductivity breaks down is called the critical current. The value of the critical current is determined by the balance of Lorentz forces and pinning forces acting on the flux lines in the superconductor. Lorentz forces proportional to the current flow tend to drive the flux lines into motion, which dissipates energy and destroys zero resistance. Pinning forces created by isolated defects in the microstructure oppose flux line motion and increase the critical current. Many kinds of artificial pinning centers have been proposed and developed to increase critical current performance, ranging from dispersal of small non-superconducting second phases to creation of defects by proton, neutron or heavy ion irradiation. In all of these methods, the pinning centers are randomly distributed over the superconducting material, causing them to operate well below their maximum efficiency. We are overcome this drawback by creating pinning centers in aperiodic lattice (see Fig 1) so that each pin site interacts strongly with only one or a few flux lines

  5. Josephson current and Andreev level dynamics in nanoscale superconducting weak links

    Energy Technology Data Exchange (ETDEWEB)

    Brunetti, Aldo

    2014-11-15

    In this thesis we focus on the interplay between proximity induced superconducting correlations and Coulomb interactions in a Josephson junction: i.e., in a system where two superconductors modeled as two s-wave superconductors at a phase difference φ are contacted by means of a weak link, in our case a quantum dot located in the contact. In the first part we study the Josephson current-phase relation for a multi-level quantum dot tunnel-contacted by two conventional s-waves superconductors. We determine in detail the conditions for observing a finite anomalous Josephson current, i.e. a supercurrent flowing at zero phase difference in a two-level dot with spin-orbit interactions, a weak magnetic (Zeeman) field, and in the presence of Coulomb interactions. This leads to an onset behavior I{sub a}∝sgn(B), interpreted as the sign of an incipient spontaneous breakdown of time-reversal symmetry. Moreover, we will provide conditions for realizing spatially separated - but topologically unprotected - Majorana bound states, whose signature in the system will be detectable via the current-phase relation. In the second part of the thesis, we address the Andreev bound state population dynamics in superconducting weak links (a superconducting 'atomic contact'), in which a poisoning mechanism due to the trapping of single quasiparticles can occur. Our motivation is that quantum coherent superconducting circuits are the most promising candidates for future large-scale quantum information processing devices. Moreover, quasiparticle poisoning has recently been observed in devices which contain a short superconducting weak link with few transport channels. We discuss a novel charge imbalance effect in the continuum quasiparticle population, which is due to phase fluctuations of the environment weakly coupled to the superconducting contact. This coupling enters the system as a transition rate connecting continuum quasiparticles and the Andreev bound state system. The

  6. Effect of epoxy impregnation on strain distribution of materials in Bi2223 superconducting coils by using synchrotron X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xinzhe, E-mail: xinzhe.jin@riken.jp [Center for Life Science Technologies, RIKEN, Yokohama-shi, Kanagawa 230-0045 (Japan); Osamura, Kozo [Research Institute for Applied Sciences, Sakyo-ku, Kyoto 606-8202 (Japan); Machiya, Shutaro [Daido University, Minami-ku, Nagoya 457-8530 (Japan); Kajiwara, Kentaro [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198 (Japan); Shobu, Takahisa [Japan Atomic Energy Agency, Sayo, Hyogo 679-5148 (Japan); Maeda, Hideaki [Center for Life Science Technologies, RIKEN, Yokohama-shi, Kanagawa 230-0045 (Japan)

    2015-11-25

    Synchrotron X-rays have been used to observe strain distributions in composite materials such as superconducting wires with a thickness of less than about 2 mm. In applications that employ wound coils of superconducting wire, it is necessary to understand the strain distribution within the coiled wire. Superconducting wires such as Bi2223 and REBCO wires approximately 4–5 mm wide are commercially available. Coiled wires of this width are too thick to easily measure using conventional X-ray techniques, especially the inner strain, because the penetration depth tends to be around 2 mm. Therefore, the beam penetration must be improved, and it is known that the penetration depth of an X-ray beam depends upon the beam energy, beam intensity, measurement material, and measurement method. In this study, we used a white X-ray diffractometer at SPring-8 to develop a method of observing the strain distribution in Bi2223 superconducting coils winded by a 4.5 mm wide Bi2223 wire. We successfully observed a clear (400) peak of the Bi2223 phase by an appropriate measurement condition, and then observed the strains of each material in the Bi2223 coils with and without epoxy impregnation. This is the first time that we have obtained the strain of a Bi2223 phase in coiled wire using synchrotron X-ray diffraction. Further synchrotron-based study of superconducting coils will be useful in the development of advanced high-field magnets. The appropriate measurement method and the obtained measurement results are presented in this paper. - Highlights: • We successfully obtained clear peaks of Bi2223 phase in 4.5 mm thick coils. • The strain behaviors of materials in the coil correspond to a three turn cycle model. • A uniform strain distribution of the Bi2223 phase was obtained by epoxy impregnation.

  7. System of cylindrical drift chambers in a superconducting solenoid

    International Nuclear Information System (INIS)

    Camilleri, L.; Blumenfeld, B.J.; Dimcovski, Z.

    1978-01-01

    A superconducting solenoid at the CERN ISR was equipped with a system of high accuracy cylindrical drift chambers. This detector consists of eight layers of field shaped drift cells with a delay line opposite each sense wire to provide coupled two dimensional readout. The design, construction, and operation of this system are discussed. The resolution and performance of the delay lines and sense wires under ISR running conditions are shown

  8. Quantum phase slips and voltage fluctuations in superconducting nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Andrew G. [I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physics Institute, Moscow (Russian Federation); National Research University Higher School of Economics, Moscow (Russian Federation); Zaikin, Andrei D. [I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physics Institute, Moscow (Russian Federation); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)

    2017-06-15

    We argue that quantum phase slips (QPS) may generate non-equilibrium voltage fluctuations in superconducting nanowires. In the low frequency limit we evaluate all cumulants of the voltage operator which obey Poisson statistics and show a power law dependence on the external bias. We specifically address quantum shot noise which power spectrum S{sub Ω} may depend non-monotonously on temperature. In the long wire limit S{sub Ω} decreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T → 0. Our predictions can be directly tested in future experiments with superconducting nanowires. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Superconducting Wind Turbine Generators

    Directory of Open Access Journals (Sweden)

    Yunying Pan

    2016-08-01

    Full Text Available Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends to introduce the basic concept and principle of superconductivity, and compare form traditional wind turbine to obtain superiority, then to summary three proposed machine concept.While superconductivity have difficulty  in modern technology and we also have proposed some challenges in achieving superconducting wind turbine finally.

  10. Superconducting cermets

    International Nuclear Information System (INIS)

    Goyal, A.; Funkenbusch, P.D.; Chang, G.C.S.; Burns, S.J.

    1988-01-01

    Two distant classes of superconducting cermets can be distinguished, depending on whether or not a fully superconducting skeleton is established. Both types of cermets have been successfully fabricated using non-noble metals, with as high as 60wt% of the metal phase. The electrical, magnetic and mechanical behavior of these composites is discussed

  11. PK-ISIS: a new superconducting ECR ion source at Pantechnik

    International Nuclear Information System (INIS)

    Villari, A.C.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Gaubert, G.; Leroy, R.; Sineau, A.; Tasset, O.; Vallerand, C.; Thuillier, T.

    2012-01-01

    The new ECR ion source PK-ISIS was recently commissioned at Pantechnik. Three superconducting coils generate the axial magnetic field configuration while the radial magnetic field is done with multi-layer permanent magnets. Special care was devoted in the design of the hexapolar structure, allowing a maximum magnetic field of 1.32 T at the wall of the 82 mm diameter plasma chamber. The three superconducting coils using Low Temperature Superconducting wires are cooled by a single double stage cryo-cooler (4.2 K). Cryogen-free technology is used, providing reliability, easy maintenance at low cost. The maximum installed RF power (18.0 GHz) is of 2 kW. Metallic beams can be produced with an oven (T max = 1400 C) installed with an angle of 5 degrees with respect to the source axis or a sputtering system, mounted in the axis of the source. The beam extraction system is constituted of three electrodes in accel-decel configuration. The new source of Pantechnik is conceived for reaching optimum performances at 18 GHz RF frequencies. PK-ISIS delivers 5 to 10 times more beam intensity than the original PK-DELIS and/or shifting the charge state distribution to higher values. PK-ISIS is built with Low Temperature Superconducting wire technology (LTS), but keeps the He-free concept, extremely important for a reliable and easy operation. The radial field circuit is permanent magnet made. Finally, PK-ISIS is also conceived for using in a High-Voltage platform with minor power consumption. The paper is followed by the slides of the presentation. (A.C.)

  12. Rf superconducting devices

    International Nuclear Information System (INIS)

    Hartwig, W.H.; Passow, C.

    1975-01-01

    Topics discussed include (1) the theory of superconductors in high-frequency fields (London surface impedance, anomalous normal surface resistance, pippard nonlocal theory, quantum mechanical model, superconductor parameters, quantum mechanical calculation techniques for the surface, impedance, and experimental verification of surface impedance theories); (2) residual resistance (separation of losses, magnetic field effects, surface resistance of imperfect and impure conductors, residual loss due to acoustic coupling, losses from nonideal surfaces, high magnetic field losses, field emission, and nonlinear effects); (3) design and performance of superconducting devices (design considerations, materials and fabrication techniques, measurement of performance, and frequency stability); (4) devices for particle acceleration and deflection (advantages and problems of using superconductors, accelerators for fast particles, accelerators for particles with slow velocities, beam optical devices separators, and applications and projects under way); (5) applications of low-power superconducting resonators (superconducting filters and tuners, oscillators and detectors, mixers and amplifiers, antennas and output tanks, superconducting resonators for materials research, and radiation detection with loaded superconducting resonators); and (6) transmission and delay lines

  13. Superconducting Ferromagnetic Nanodiamond.

    Science.gov (United States)

    Zhang, Gufei; Samuely, Tomas; Xu, Zheng; Jochum, Johanna K; Volodin, Alexander; Zhou, Shengqiang; May, Paul W; Onufriienko, Oleksandr; Kačmarčík, Jozef; Steele, Julian A; Li, Jun; Vanacken, Johan; Vacík, Jiri; Szabó, Pavol; Yuan, Haifeng; Roeffaers, Maarten B J; Cerbu, Dorin; Samuely, Peter; Hofkens, Johan; Moshchalkov, Victor V

    2017-06-27

    Superconductivity and ferromagnetism are two mutually antagonistic states in condensed matter. Research on the interplay between these two competing orderings sheds light not only on the cause of various quantum phenomena in strongly correlated systems but also on the general mechanism of superconductivity. Here we report on the observation of the electronic entanglement between superconducting and ferromagnetic states in hydrogenated boron-doped nanodiamond films, which have a superconducting transition temperature T c ∼ 3 K and a Curie temperature T Curie > 400 K. In spite of the high T Curie , our nanodiamond films demonstrate a decrease in the temperature dependence of magnetization below 100 K, in correspondence to an increase in the temperature dependence of resistivity. These anomalous magnetic and electrical transport properties reveal the presence of an intriguing precursor phase, in which spin fluctuations intervene as a result of the interplay between the two antagonistic states. Furthermore, the observations of high-temperature ferromagnetism, giant positive magnetoresistance, and anomalous Hall effect bring attention to the potential applications of our superconducting ferromagnetic nanodiamond films in magnetoelectronics, spintronics, and magnetic field sensing.

  14. Superconductivity and its application

    International Nuclear Information System (INIS)

    Spadoni, M.

    1988-01-01

    This paper, after a short introduction to superconductivity and to multifilamentary superconducting composites is aiming to review the state of the art and the future perspective of some of the applications of the superconducting materials. The main interest is focussed to large scale applications like, for istance, magnets for accelerators or fusion reactors, superconducting system for NMR thomography, etc. A short paragraph is dedicated to applications for high sensitivity instrumentation. The paper is then concluded by some considerations about the potentialities of the newly discovered high critical temperature materials

  15. WORKSHOPS: Radiofrequency superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    In the continual push towards higher energy particle beams, superconducting radiofrequency techniques now play a vital role, highlighted in the fifth workshop on radiofrequency superconductivity, held at DESY from 19 - 24 August 1991

  16. WORKSHOPS: Radiofrequency superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-01-15

    In the continual push towards higher energy particle beams, superconducting radiofrequency techniques now play a vital role, highlighted in the fifth workshop on radiofrequency superconductivity, held at DESY from 19 - 24 August 1991.

  17. Design and fabrication of a 30 T superconducting solenoid using overpressure processed Bi2212 round wire

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, Gene [Muons, Inc., Batavia, IL (United States); Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2016-02-18

    High field superconducting magnets are used in particle colliders, fusion energy devices, and spectrometers for medical imaging and advanced materials research. Magnets capable of generating fields of 20-30 T are needed by future accelerator facilities. A 20-30 T magnet will require the use of high-temperature superconductors (HTS) and therefore the challenges of high field HTS magnet development need to be addressed. Superconducting Bi2Sr2CaCu2Ox (Bi2212) conductors fabricated by the oxide-powder-in-tube (OPIT) technique have demonstrated the capability to carry large critical current density of 105 A/cm2 at 4.2 K and in magnetic fields up to 45 T. Available in round wire multi-filamentary form, Bi2212 may allow fabrication of 20-50 T superconducting magnets. Until recently the performance of Bi2212 has been limited by challenges in realizing high current densities (Jc ) in long lengths. This problem now is solved by the National High Magnetic Field Lab using an overpressure (OP) processing technique, which uses external pressure to process the conductor. OP processing also helps remove the ceramic leakage that results when Bi-2212 liquid leaks out from the sheath material and reacts with insulation, coil forms, and flanges. Significant advances have also been achieved in developing novel insulation materials (TiO2 coating) and Ag-Al sheath materials that have higher mechanical strengths than Ag-0.2wt.% Mg, developing heat treatment approaches to broadening the maximum process temperature window, and developing high-strength, mechanical reinforced Bi-2212 cables. In the Phase I work, we leveraged these new opportunities to prototype overpressure processed solenoids and test them in background fields of up to 14 T. Additionally a design of a fully superconducting 30 T solenoid was produced. This work in conjunction with the future path outlined in the Phase II proposal would

  18. 'Speedy' superconducting circuits

    International Nuclear Information System (INIS)

    Holst, T.

    1994-01-01

    The most promising concept for realizing ultra-fast superconducting digital circuits is the Rapid Single Flux Quantum (RSFQ) logic. The basic physical principle behind RSFQ logic, which include the storage and transfer of individual magnetic flux quanta in Superconducting Quantum Interference Devices (SQUIDs), is explained. A Set-Reset flip-flop is used as an example of the implementation of an RSFQ based circuit. Finally, the outlook for high-temperature superconducting materials in connection with RSFQ circuits is discussed in some details. (au)

  19. Superconductivity

    International Nuclear Information System (INIS)

    Buller, L.; Carrillo, F.; Dietert, R.; Kotziapashis, A.

    1989-01-01

    Superconductors are materials which combine the property of zero electric resistance with the capability to exclude any adjacent magnetic field. This leads to many large scale applications such as the much publicized levitating train, generation of magnetic fields in MHD electric generators, and special medical diagnostic equipment. On a smaller-scale, superconductive materials could replace existing resistive connectors and decrease signal delays by reducing the RLC time constants. Thus, a computer could operate at much higher speeds, and consequently at lower power levels which would reduce the need for heat removal and allow closer spacing of circuitry. Although technical advances and proposed applications are constantly being published, it should be recognized that superconductivity is a slowly developing technology. It has taken scientists almost eighty years to learn what they now know about this material and its function. The present paper provides an overview of the historical development of superconductivity and describes some of the potential applications for this new technology as it pertains to the electronics industry

  20. Luminescence and squeezing of a superconducting light-emitting diode

    Science.gov (United States)

    Hlobil, Patrik; Orth, Peter P.

    2015-05-01

    We investigate a semiconductor p -n junction in contact with superconducting leads that is operated under forward bias as a light-emitting diode. The presence of superconductivity results in a significant increase of the electroluminescence in a sharp frequency window. We demonstrate that the tunneling of Cooper pairs induces an additional luminescence peak on resonance. There is a transfer of superconducting to photonic coherence that results in the emission of entangled photon pairs and squeezing of the fluctuations in the quadrature amplitudes of the emitted light. We show that the squeezing angle can be electrically manipulated by changing the relative phase of the order parameters in the superconductors. We finally derive the conditions for lasing in the system and show that the laser threshold is reduced due to superconductivity. This reveals how the macroscopic coherence of a superconductor can be used to control the properties of light.

  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. Finite Element Analysis of Transverse Compressive Loads on Superconducting Nb3Sn Wires Containing Voids

    Science.gov (United States)

    D'Hauthuille, Luc; Zhai, Yuhu; Princeton Plasma Physics Lab Collaboration; University of Geneva Collaboration

    2015-11-01

    High field superconductors play an important role in many large-scale physics experiments, particularly particle colliders and fusion devices such as the LHC and ITER. The two most common superconductors used are NbTi and Nb3Sn. Nb3Sn wires are favored because of their significantly higher Jc, allowing them to produce much higher magnetic fields. The main disadvantage is that the superconducting performance of Nb3Sn is highly strain-sensitive and it is very brittle. The strain-sensitivity is strongly influenced by two factors: plasticity and cracked filaments. Cracks are induced by large stress concentrators due to the presence of voids. We will attempt to understand the correlation between Nb3Sn's irreversible strain limit and the void-induced stress concentrations around the voids. We will develop accurate 2D and 3D finite element models containing detailed filaments and possible distributions of voids in a bronze-route Nb3Sn wire. We will apply a compressive transverse load for the various cases to simulate the stress response of a Nb3Sn wire from the Lorentz force. Doing this will further improve our understanding of the effect voids have on the wire's mechanical properties, and thus, the connection between the shape & distribution of voids and performance degradation.

  4. A high efficiency superconducting nanowire single electron detector

    NARCIS (Netherlands)

    Rosticher, M.; Ladan, F.R.; Maneval, J.P.; Dorenbos, S.N.; Zijlstra, T.; Klapwijk, T.M.; Zwiller, V.; Lupa?cu, A.; Nogues, G.

    2010-01-01

    We report the detection of single electrons using a Nb0.7Ti0.3N superconducting wire deposited on an oxidized silicon substrate. While it is known that this device is sensitive to single photons, we show that it also detects single electrons with kilo-electron-volt energy emitted from the cathode of

  5. High-Density Superconducting Cables for Advanced ACTPol

    Science.gov (United States)

    Pappas, C. G.; Austermann, J.; Beall, J. A.; Duff, S. M.; Gallardo, P. A.; Grace, E.; Henderson, S. W.; Ho, S. P.; Koopman, B. J.; Li, D.; hide

    2016-01-01

    Advanced ACTPol (AdvACT) is an upcoming Atacama Cosmology Telescope (ACT) receiver upgrade, scheduled to deploy in 2016, that will allow measure- ment of the cosmic microwave background polarization and temperature to the highest precision yet with ACT. The AdvACT increase in sensitivity is partly provided by an increase in the number of transition-edge sensors (TESes) per array by up to a factor of two over the current ACTPol receiver detector arrays. The high-density AdvACT TES arrays require 70 µ m pitch superconducting flexible cables (flex) to connect the detec- tor wafer to the first-stage readout electronics. Here, we present the flex fabrication process and test results. For the flex wiring layer, we use a 400-nm-thick sputtered alu- minum film. In the center of the cable, the wiring is supported by a polyimide substrate, which smoothly transitions to a bare (uncoated with polyimide) silicon substrate at the ends of the cable for a robust wedge wire-bonding interface. Tests on the first batch of flex made for the first AdvACT array show that the flex will meet the requirements for AdvACT, with a superconducting critical current above 1 mA at 500 mK, resilience to mechanical and cryogenic stress, and a room temperature yield of 97%.

  6. A Cryogenic Magnetostrictive Actuator Using a Persistent High Temperature Superconducting Magnet. Part 1; Concept and Design

    Science.gov (United States)

    Horner, Garnett; Bromberg, Leslie; Teter, J. P.

    2000-01-01

    Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSCCO 2212 with a magnetostrictive element will be discussed.

  7. Superconductivity basics and applications to magnets

    CERN Document Server

    Sharma, R G

    2015-01-01

    This book presents the basics and applications of superconducting magnets. It explains the phenomenon of superconductivity, theories of superconductivity, type II superconductors and high-temperature cuprate superconductors. The main focus of the book is on the application to superconducting magnets to accelerators and fusion reactors and other applications of superconducting magnets. The thermal and electromagnetic stability criteria of the conductors and the present status of the fabrication techniques for future magnet applications are addressed. The book is based on the long experience of the author in studying superconducting materials, building magnets and numerous lectures delivered to scholars. A researcher and graduate student will enjoy reading the book to learn various aspects of magnet applications of superconductivity. The book provides the knowledge in the field of applied superconductivity in a comprehensive way.

  8. A method for building low loss multi-layer wiring for superconducting microwave devices

    Science.gov (United States)

    Dunsworth, A.; Barends, R.; Chen, Yu; Chen, Zijun; Chiaro, B.; Fowler, A.; Foxen, B.; Jeffrey, E.; Kelly, J.; Klimov, P. V.; Lucero, E.; Mutus, J. Y.; Neeley, M.; Neill, C.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Neven, H.; Martinis, John M.; Megrant, A.

    2018-02-01

    Complex integrated circuits require multiple wiring layers. In complementary metal-oxide-semiconductor processing, these layers are robustly separated by amorphous dielectrics. These dielectrics would dominate energy loss in superconducting integrated circuits. Here, we describe a procedure that capitalizes on the structural benefits of inter-layer dielectrics during fabrication and mitigates the added loss. We use a deposited inter-layer dielectric throughout fabrication and then etch it away post-fabrication. This technique is compatible with foundry level processing and can be generalized to make many different forms of low-loss wiring. We use this technique to create freestanding aluminum vacuum gap crossovers (airbridges). We characterize the added capacitive loss of these airbridges by connecting ground planes over microwave frequency λ/4 coplanar waveguide resonators and measuring resonator loss. We measure a low power resonator loss of ˜3.9 × 10-8 per bridge, which is 100 times lower than that of dielectric supported bridges. We further characterize these airbridges as crossovers, control line jumpers, and as part of a coupling network in gmon and fluxmon qubits. We measure qubit characteristic lifetimes (T1s) in excess of 30 μs in gmon devices.

  9. Conceptual design and development of a superconducting bus-line for the Large Helical Device

    International Nuclear Information System (INIS)

    Mito, T.; Takahata, K.; Yamada, S.; Yamamoto, J.; Uede, T.; Ikeda, M.

    1993-01-01

    A superconducting bus-line is proposed and preliminarily tested as an electrical feeder between the superconducting coils of the Large Helical Device (LHD) and their electrical power supply. The bus-line consists of a superconductor and its cryogenic transfer-line. The superconductor is a specially developed aluminum stabilized NbTi wire, which is installed in the innermost channel of the transfer-line. The vacuum insulated transfer-line consists of four corrugated tubes assembled coaxially. Liquid helium flows through the innermost channel and shield gas flows through another annular channel in the line. We are completing the conceptual design of the bus-line and the installation plan for the LHD experimental hall and are carrying out development of wires, including an investigation of their mechanical properties and electrical insulation. This report describes the conceptual design of the superconducting bus-line for the LHD, and the results we obtained recently during the design and development of a full-scale demonstration facility. (orig.)

  10. Overview of superconductivity in Japan - Strategy road map and R and D status

    International Nuclear Information System (INIS)

    Tsukamoto, O.

    2008-01-01

    Superconducting technology benefits society in broad fields; environment/energy, life science, manufacturing industry and information and communication. Superconducting equipments and devices used in various fields are divided into two categories, electric and electronic applications. Technologies in those applications are progressing remarkably owing to firm and consistent supports by various national projects. The final target of the NEDO R and D project of fundamental technology for superconductivity applications to develop 500 m long coated conductors (CCs) of the critical current 300 A/cm (at 77 K, 0 T) will be fulfilled by the end of JFY 2007 and manufacturing process to produce extremely low-cost CCs is to be developed to make the applications realistic. Preliminary works to develop power apparatuses using CCs have started in the frame of the R and D project for the fundamental technology and have produced significant results. Performance of BSCCO/Ag-sheathed wires has been improved greatly and various applications using those wires are being developed. R and D projects for SMES, power cable, flywheel energy storage and rotating machines are going to introduce those equipments to the real world. Technologies of SQUID and SFQ, basic devices of the electronic applications, are progressing dramatically also owing to various national projects. In this back ground the technology strategy map in the field of superconducting technology was formulated to prioritize investments in R and D by clearly defining the objectives and inspire autonomous R and D actives in various fields of industries. R and D activities in the superconducting technologies are to be scheduled following this strategy map

  11. Superconducting magnets and cryogenics for the steady state superconducting tokamak SST-1

    International Nuclear Information System (INIS)

    Saxena, Y.C.

    2000-01-01

    SST-1 is a steady state superconducting tokamak for studying the physics of the plasma processes in tokamak under steady state conditions and to learn technologies related to the steady state operation of the tokamak. SST-1 will have superconducting magnets made from NbTi based conductors operating at 4.5 K temperature. The design of the superconducting magnets and the cryogenic system of SST-1 tokamak are described. (author)

  12. Vector superconductivity in cosmic strings

    International Nuclear Information System (INIS)

    Dvali, G.R.; Mahajan, S.M.

    1992-03-01

    We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

  13. Foreword: Focus on Superconductivity in Semiconductors

    Directory of Open Access Journals (Sweden)

    Yoshihiko Takano

    2008-01-01

    Full Text Available Since the discovery of superconductivity in diamond, much attention has been given to the issue of superconductivity in semiconductors. Because diamond has a large band gap of 5.5 eV, it is called a wide-gap semiconductor. Upon heavy boron doping over 3×1020 cm−3, diamond becomes metallic and demonstrates superconductivity at temperatures below 11.4 K. This discovery implies that a semiconductor can become a superconductor upon carrier doping. Recently, superconductivity was also discovered in boron-doped silicon and SiC semiconductors. The number of superconducting semiconductors has increased. In 2008 an Fe-based superconductor was discovered in a research project on carrier doping in a LaCuSeO wide-gap semiconductor. This discovery enhanced research activities in the field of superconductivity, where many scientists place particular importance on superconductivity in semiconductors.This focus issue features a variety of topics on superconductivity in semiconductors selected from the 2nd International Workshop on Superconductivity in Diamond and Related Materials (IWSDRM2008, which was held at the National Institute for Materials Science (NIMS, Tsukuba, Japan in July 2008. The 1st workshop was held in 2005 and was published as a special issue in Science and Technology of Advanced Materials (STAM in 2006 (Takano 2006 Sci. Technol. Adv. Mater. 7 S1.The selection of papers describe many important experimental and theoretical studies on superconductivity in semiconductors. Topics on boron-doped diamond include isotope effects (Ekimov et al and the detailed structure of boron sites, and the relation between superconductivity and disorder induced by boron doping. Regarding other semiconductors, the superconducting properties of silicon and SiC (Kriener et al, Muranaka et al and Yanase et al are discussed, and In2O3 (Makise et al is presented as a new superconducting semiconductor. Iron-based superconductors are presented as a new series of high

  14. Status of RF superconductivity at Argonne

    International Nuclear Information System (INIS)

    Shepard, K.W.

    1990-01-01

    Development of a superconducting slow-wave structures began at Argonne National Laboratory (ANL) in 1971, and led to the first superconducting heavy-ion linac (ATLAS - the Argonne Tandem-Linac Accelerator System). The Physics Division at ANL has continued to develop superconducting RF technology for accelerating heavy-ions, with the result that the linac has been in an almost continuous process of upgrade and expansion. In 1987, the Engineering Physics Division at ANL began developing of superconducting RF components for the acceleration of high-brightness proton and deuterium beams. The two divisions collaborate in work on several applications of RF superconductivity, and also in work to develop the technology generally. The present report briefly describes major features of the superconducting heavy-ion linac (very-low-velocity superconducting linac, positive ion injector), proton accelerating structures (superconducting resonant cavities for acceleration of high-current proton and deuteron beams, RF properties of oxide superconductors), and future work. Both divisions expect to continue a variety of studies, frequently in collaboration, to advance the basic technology of RF superconductivity. (N.K.)

  15. Unconventional superconductivity in heavy-fermion compounds

    Energy Technology Data Exchange (ETDEWEB)

    White, B.D. [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093 (United States); Thompson, J.D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maple, M.B., E-mail: mbmaple@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Advanced Nanoscience, University of California, San Diego, La Jolla, CA 92093 (United States)

    2015-07-15

    Highlights: • Quasiparticles in heavy-fermion compounds are much heavier than free electrons. • Superconductivity involves pairing of these massive quasiparticles. • Quasiparticle pairing mediated by magnetic or quadrupolar fluctuations. • We review the properties of superconductivity in heavy-fermion compounds. - Abstract: Over the past 35 years, research on unconventional superconductivity in heavy-fermion systems has evolved from the surprising observations of unprecedented superconducting properties in compounds that convention dictated should not superconduct at all to performing explorations of rich phase spaces in which the delicate interplay between competing ground states appears to support emergent superconducting states. In this article, we review the current understanding of superconductivity in heavy-fermion compounds and identify a set of characteristics that is common to their unconventional superconducting states. These core properties are compared with those of other classes of unconventional superconductors such as the cuprates and iron-based superconductors. We conclude by speculating on the prospects for future research in this field and how new advances might contribute towards resolving the long-standing mystery of how unconventional superconductivity works.

  16. A superconducting homopolar motor and generator—new approaches

    International Nuclear Information System (INIS)

    Fuger, Rene; Matsekh, Arkadiy; Kells, John; Sercombe, D B T; Guina, Ante

    2016-01-01

    Homopolar machines were the first continuously running electromechanical converters ever demonstrated but engineering challenges and the rapid development of AC technology prevented wider commercialisation. Recent developments in superconducting, cryogenic and sliding contact technology together with new areas of application have led to a renewed interest in homopolar machines. Some of the advantages of these machines are ripple free constant torque, pure DC operation, high power-to-weight ratio and that rotating magnets or coils are not required. In this paper we present our unique approach to high power and high torque homopolar electromagnetic turbines using specially designed high field superconducting magnets and liquid metal current collectors. The unique arrangement of the superconducting coils delivers a high static drive field as well as effective shielding for the field critical sliding contacts. The novel use of additional shielding coils reduces weight and stray field of the system. Liquid metal current collectors deliver a low resistance, stable and low maintenance sliding contact by using a thin liquid metal layer that fills a circular channel formed by the moving edge of a rotor and surrounded by a conforming stationary channel of the stator. Both technologies are critical to constructing high performance machines. Homopolar machines are pure DC devices that utilise only DC electric and magnetic fields and have no AC losses in the coils or the supporting structure. Guina Energy Technologies has developed, built and tested different motor and generator concepts over the last few years and has combined its experience to develop a new generation of homopolar electromagnetic turbines. This paper summarises the development process, general design parameters and first test results of our high temperature superconducting test motor. (paper)

  17. A superconducting homopolar motor and generator—new approaches

    Science.gov (United States)

    Fuger, Rene; Matsekh, Arkadiy; Kells, John; Sercombe, D. B. T.; Guina, Ante

    2016-03-01

    Homopolar machines were the first continuously running electromechanical converters ever demonstrated but engineering challenges and the rapid development of AC technology prevented wider commercialisation. Recent developments in superconducting, cryogenic and sliding contact technology together with new areas of application have led to a renewed interest in homopolar machines. Some of the advantages of these machines are ripple free constant torque, pure DC operation, high power-to-weight ratio and that rotating magnets or coils are not required. In this paper we present our unique approach to high power and high torque homopolar electromagnetic turbines using specially designed high field superconducting magnets and liquid metal current collectors. The unique arrangement of the superconducting coils delivers a high static drive field as well as effective shielding for the field critical sliding contacts. The novel use of additional shielding coils reduces weight and stray field of the system. Liquid metal current collectors deliver a low resistance, stable and low maintenance sliding contact by using a thin liquid metal layer that fills a circular channel formed by the moving edge of a rotor and surrounded by a conforming stationary channel of the stator. Both technologies are critical to constructing high performance machines. Homopolar machines are pure DC devices that utilise only DC electric and magnetic fields and have no AC losses in the coils or the supporting structure. Guina Energy Technologies has developed, built and tested different motor and generator concepts over the last few years and has combined its experience to develop a new generation of homopolar electromagnetic turbines. This paper summarises the development process, general design parameters and first test results of our high temperature superconducting test motor.

  18. Superconducting magnet development in Japan

    International Nuclear Information System (INIS)

    Yasukochi, K.

    1983-01-01

    The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb 3 Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting μ meson channel and π meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration

  19. Electro-mechanical characterization of MgB2 wires for the Superconducting Link Project at CERN

    Science.gov (United States)

    Konstantopoulou, K.; Ballarino, A.; Gharib, A.; Stimac, A.; Garcia Gonzalez, M.; Perez Fontenla, A. T.; Sugano, M.

    2016-08-01

    In previous years, the R & D program between CERN and Columbus Superconductors SpA led to the development of several configurations of MgB2 wires. The aim was to achieve excellent superconducting properties in high-current MgB2 cables for the HL-LHC upgrade. In addition to good electrical performance, the superconductor shall have good mechanical strength in view of the stresses during operation (Lorenz forces and thermal contraction) and handling (tension and bending) during cabling and installation at room temperature. Thus, the study of the mechanical properties of MgB2 wires is crucial for the cable design and its functional use. In the present work we report on the electro-mechanical characterization of ex situ processed composite MgB2 wires. Tensile tests (critical current versus strain) were carried out at 4.2 K and in a 3 T external field by means of a purpose-built bespoke device to determine the irreversible strain limit of the wire. The minimum bending radius of the wire was calculated taking into account the dependence of the critical current with the strain and it was then used to obtain the minimum twist pitch of MgB2 wires in the cable. Strands extracted from cables having different configurations were tested to quantify the critical current degradation. The Young’s modulus of the composite wire was measured at room temperature. Finally, all measured mechanical parameters will be used to optimize an 18-strand MgB2 cable configuration.

  20. Superconducting joint of Bi-2223/Ag superconducting tapes by diffusion bonding

    International Nuclear Information System (INIS)

    Guo Wei; Zou Guisheng; Wu Aiping; Wang Yanjun; Bai Hailin; Ren Jialie

    2009-01-01

    61-Filaments Bi-2223/Ag superconducting tapes have been joined by diffusion bonding. The critical currents (I C s) of the joints are obtained by using standard four probe method under no magnetic field in the liquid nitrogen. The microstructures of the joints are evaluated by the electron microscope in electron backscatter diffraction mode and the phase compositions of the superconducting cores of the joint and the original tape are determined by X-ray diffraction (XRD). The results show diffusion bonding is effective bonding technique for HTS tapes, and the bonding time is reduced greatly from hundreds of hours to a few hours, and the bonding pressure also changes from 140-4000 MPa to 3 MPa. Furthermore, the diffusion bonding joints sustain superconducting properties, and the critical current ratios (CCR O ) of the joints are in the range of 35%-80%. Microstructures of the typical joint display a good bonding and some defects existed in traditional method are avoided. XRD results show that the phase compositions of the superconducting cores have no obvious changes before and after diffusion bonding, which offers physical and material bases for high superconducting property of the joints.

  1. Superconductivity in the 1990's

    International Nuclear Information System (INIS)

    Stekly, Z.J.J.

    1990-01-01

    Superconducting magnets, coils or windings are the basis for a range of major applications in the energy area such as energy storage in superconducting coils, magnets for fusion research, and rotating machinery. Other major applications of superconductivity include high energy physics where 1000 superconducting magnets are operated continuously in the Tevatron at Fermilab in Illinois, over 12,000 superconducting magnets will be required for the superconducting Super Collider being build near Dallas. The largest commercial application of superconductors is in magnets for magnetic resonance imaging (MRI) - a new medical diagnostic imaging technique with about 2,000 systems installed worldwide. These form a sizable technology base on which to evaluate and push forward applications such as magneto hydrodynamic propulsion of seagoing vessels. The attractiveness of which depends ultimately on the characteristics of the superconducting magnet. The magnet itself is a combination of several technology areas - the conductors, magnetics, structures and cryogenics. This paper reviews state-of-the-art in each of the technology areas as they relate to superconductors

  2. Superconductivity in doped Dirac semimetals

    Science.gov (United States)

    Hashimoto, Tatsuki; Kobayashi, Shingo; Tanaka, Yukio; Sato, Masatoshi

    2016-07-01

    We theoretically study intrinsic superconductivity in doped Dirac semimetals. Dirac semimetals host bulk Dirac points, which are formed by doubly degenerate bands, so the Hamiltonian is described by a 4 ×4 matrix and six types of k -independent pair potentials are allowed by the Fermi-Dirac statistics. We show that the unique spin-orbit coupling leads to characteristic superconducting gap structures and d vectors on the Fermi surface and the electron-electron interaction between intra and interorbitals gives a novel phase diagram of superconductivity. It is found that when the interorbital attraction is dominant, an unconventional superconducting state with point nodes appears. To verify the experimental signature of possible superconducting states, we calculate the temperature dependence of bulk physical properties such as electronic specific heat and spin susceptibility and surface state. In the unconventional superconducting phase, either dispersive or flat Andreev bound states appear between point nodes, which leads to double peaks or a single peak in the surface density of states, respectively. As a result, possible superconducting states can be distinguished by combining bulk and surface measurements.

  3. A sourcebook of titanium alloy superconductivity

    CERN Document Server

    Collings, E W

    1983-01-01

    In less than two decades the concept of supercon­ In every field of science there are one or two ductivity has been transformed from a laboratory individuals whose dedication, combined with an innate curiosity to usable large-scale applications. In the understanding, permits them to be able to grasp, late 1960's the concept of filamentary stabilization condense, and explain to the rest of us what that released the usefulness of zero resistance into the field is all about. For the field of titanium alloy marketplace, and the economic forces that drive tech­ superconductivity, such an individual is Ted Collings. nology soon focused on niobium-titanium alloys. They His background as a metallurgist has perhaps given him are ductile and thus fabricable into practical super­ a distinct advantage in understanding superconduc­ conducting wires that have the critical currents and tivity in titanium alloys because the optimization of fields necessary for large-scale devices. More than superconducting parameters in ...

  4. Superconductivity in power engineering

    International Nuclear Information System (INIS)

    1989-01-01

    This proceedings volume presents 24 conference papers and 15 posters dealing with the following aspects: 1) Principles and elementary aspects of high-temperature superconductivity (3 plenary lectures); 2) Preparation, properties and materials requirements of metallic or oxide superconductors (critical current behaviour, soldered joints, structural studies); 3) Magnet technology (large magnets for thermonuclear fusion devices; magnets for particle accelerators and medical devices); 4) Magnetic levitation and superconductivity; 5) Cryogenics; 6) Energy storage systems using superconducting coils (SMES); 7) Superconducting power transmission cables, switches, transformers, and generator systems for power plant; 8) Supporting activities, industrial aspects, patents. There are thirty-eight records in the ENERGY database relating to individual conference papers. (MM) [de

  5. Comparison of water degradation of YBaCuO superconducting films made from different structures

    International Nuclear Information System (INIS)

    Chang, C.; Tsai, J.A.

    1988-01-01

    Immersion of YBaCuO superconducting films in water has shown a large difference in degradation between structures with and without silver. For the structures containing silver layers and depositing at a high temperature, superconducting films with zero resistance at 87 K remain superconductive at 77 K after 5 h immersion in water, with an increase in room-temperature film resistance by a factor of 4; the contact resistance remains low after 60 h of immersion, allowing the measurement at low temperatures. For the structures containing no silver and depositing at room temperature, the contact resistance rapidly increases with immersion times, making the measurement at 77 K difficult after 5 min of immersion. Changes in the sharpness of the superconductive transition, and structures of the films due to the water immersion are also compared

  6. Magnetic Measurement System for the NSLS Superconducting Undulator Vertical Test Facility

    CERN Document Server

    Harder, David; Skaritka, John

    2005-01-01

    One of the challenges of small-gap superconducting undulators is measurement of magnetic fields within the cold bore to characterize the device performance and to determine magnetic field errors for correction or shimming, as is done for room-temperature undulators. Both detailed field maps and integrated field measurements are required. This paper describes a 6-element, cryogenic Hall probe field mapper for the NSLS Superconducting Undulator Vertical Test Facility (VTF). The probe is designed to work in an aperture only 3 mm high. A pulsed-wire insert is also being developed, for visualization of the trajectory, for locating steering errors and for determining integrated multi-pole errors. The pulsed-wire insert will be interchangeable with the Hall probe mapper. The VTF and the magnetic measurement systems can accommodate undulators up to 0.4 m in length.

  7. Superconducting magnets for a muon collider

    International Nuclear Information System (INIS)

    Green, M.A.

    1996-01-01

    The existence of a muon collider will be dependent on the use of superconducting magnets. Superconducting magnets for the μ - μ + collider will be found in the following locations: the π - π + capture system, the muon phase rotation system, the muon cooling system, the recirculating acceleration system, the collider ring, and the collider detector system. This report describes superconducting magnets for each of these sections except the detector. In addition to superconducting magnets, superconducting RF cavities will be found in the recirculating accelerator sections and the collider ring. The use of superconducting magnets is dictated by the need for high magnetic fields in order to reduce the length of various machine components. The performance of all of the superconducting magnets will be affected the energy deposited from muon decay products. (orig.)

  8. HTS Wire Development Workshop: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  9. Stress/strain characteristics of Cu alloy sheath in situ processed MgB2 superconducting wires

    International Nuclear Information System (INIS)

    Katagiri, Kazumune; Kasaba, Koichi; Shoji, Yoshitaka

    2005-01-01

    The mechanical properties of copper and copper alloy (Cu-Zr, Cu-Be and Cu-Cr) sheath in situ PIT-processed MgB 2 superconducting wires were studied at room temperature (RT) and 4.2 K. The effects of stress-strain on the critical current (I c ) of the wires have also been studied at 4.2 K and in magnetic fields up to 5 T. It has been clarified that alloying the Cu sheath significantly increases the yield and flow stresses of the wires at both RT and 4.2 K. The 0.5% flow stresses of the Cu alloy sheath wire were 147-237 MPa, whereas that of Cu was 55 MPa. At RT, serration corresponding to multiple cracking was observed around a strain of 0.4% and the stress-strain curves saturated beyond that point. The strain dependence of I c prior to the critical strain (ε irr ) was different depending on the magnetic field; being almost constant at 2 T and increasing with strain at 5 T. The I c decreased beyond ε irr , which is much larger for Cu alloy sheath wires as compared to Cu sheath wire. This is due to the difference in the residual compressive strain in the MgB 2 core during cooling from the heat-treatment temperature to 4.2 K, which is determined through relaxation by yielding in the sheath materials. The transverse compression tests revealed that the I c of the Cu alloy sheath wire did not degrade up to 314 MPa, which is also higher than that of Cu sheath wire. (author)

  10. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

    2010-01-01

    , the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10......We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future...... offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However...

  11. Three-terminal superconducting devices

    International Nuclear Information System (INIS)

    Gallagher, W.J.

    1985-01-01

    The transistor has a number of properties that make it so useful. The authors discuss these and the additional properties a transistor would need to have for high performance applications at temperatures where superconductivity could contribute advantages to system-level performance. These properties then serve as criteria by which to evaluate three-terminal devices that have been proposed for applications at superconducting temperatures. FETs can retain their transistor properties at low temperatures, but their power consumption is too large for high-speed, high-density cryogenic applications. They discuss in detail why demonstrated superconducting devices with three terminals -Josephson effect based devices, injection controlled weak links, and stacked tunnel junction devices such as the superconducting transistor proposed by K. Gray and the quiteron -- each fail to have true transistor-like properties. They conclude that the potentially very rewarding search for a transistor compatible with superconductivity in high performance applications must be in new directions

  12. Korea's developmental program for superconductivity

    Science.gov (United States)

    Hong, Gye-Won; Won, Dong-Yeon; Kuk, Il-Hyun; Park, Jong-Chul

    1995-04-01

    Superconductivity research in Korea was firstly carried out in the late 70's by a research group in Seoul National University (SNU), who fabricated a small scale superconducting magnetic energy storage system under the financial support from Korea Electric Power Company (KEPCO). But a few researchers were involved in superconductivity research until the oxide high Tc superconductor was discovered by Bednorz and Mueller. After the discovery of YBaCuO superconductor operating above the boiling point of liquid nitrogen (77 K)(exp 2), Korean Ministry of Science and Technology (MOST) sponsored a special fund for the high Tc superconductivity research to universities and national research institutes by recognizing its importance. Scientists engaged in this project organized 'High Temperature Superconductivity Research Association (HITSRA)' for effective conducting of research. Its major functions are to coordinate research activities on high Tc superconductivity and organize the workshop for active exchange of information. During last seven years the major superconductivity research has been carried out through the coordination of HITSRA. The major parts of the Korea's superconductivity research program were related to high temperature superconductor and only a few groups were carrying out research on conventional superconductor technology, and Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI) have led this research. In this talk, the current status and future plans of superconductivity research in Korea will be reviewed based on the results presented in interim meeting of HITSRA, April 1-2, 1994. Taejeon, as well as the research activity of KAERI.

  13. Superconducting machines. Chapter 4

    International Nuclear Information System (INIS)

    Appleton, A.D.

    1977-01-01

    A brief account is given of the principles of superconductivity and superconductors. The properties of Nb-Ti superconductors and the method of flux stabilization are described. The basic features of superconducting d.c. machines are illustrated by the use of these machines for ship propulsion, steel-mill drives, industrial drives, aluminium production, and other d.c. power supplies. Superconducting a.c. generators and their design parameters are discussed. (U.K.)

  14. Superconductivity at the industrial scale

    International Nuclear Information System (INIS)

    Tixador, P.; Lebrun, Ph.

    2011-01-01

    The discovery of superconductivity is 100 years old but theoretical works are still necessary: the BCS theory does not apply to the new families of high temperature superconducting materials discovered after 1986. In 2001 it was discovered that MgB 2 is superconducting at 39 K, this critical temperature is not the highest but MgB 2 is easy to produce and cheap. Today's highest critical temperature under atmospheric pressure is that of the HgTlBaCaCuO compound: 138 K. The complexity and the cost of cryogenic systems restrain the applications of superconductivity. The author reviews the applications of superconducting in medical imaging, particle detectors, and in the safety systems of power networks. (A.C.)

  15. Process of producing superconducting bar magnets

    International Nuclear Information System (INIS)

    Wilson, M.A.

    1988-01-01

    A method of forming a magnet having an established magnetic field is described comprising; (1) establishing a magnetic field of the desired extent and shape; (2) providing a superconducting material of desired shape; (3) positioning the material of (2) in field (1) while at a temperature above the critical temperature of the superconducting material so as to apply a magnetic field on the superconducting material; (4) cooling the superconducting material while in magnetic field (1) to below the critical temperature of the superconducting material; (5) removing the superconducting material from the magnetic field while in the supercooled condition; and (6) maintaining the material at or below the critical temperature

  16. Cryocooled superconducting magnets for high magnetic fields at the HFLSM and future collaboration with the TML

    International Nuclear Information System (INIS)

    Watanabe, K; Nishijima, G; Awaji, S; Koyama, K; Takahashi, K; Kobayashi, N; Kiyoshi, T

    2006-01-01

    A hybrid magnet needs a large amount of liquid helium for operation. In order to make an easy-to-operate hybrid magnet system, we constructed a cryocooled 28 T hybrid magnet, consisting of an outer cryocooled 10 T superconducting magnet and an inner traditional water-cooled 19 T resistive magnet. As a performance test, the cryocooled hybrid magnet generated 27.5 T in a 32 mm room temperature experimental bore. As long as Nb3Sn superconducting wires are employed, the expected maximum high field generation in the cryocooled superconducting magnet will be 17 T at 5 K. We adopted the high temperature superconducting insert coil, employing Ag-sheathed Bi 2 Sr 2 Ca 2 Cu 3 O 10 superconducting tape. In combination with the low temperature 16.5 T back-up coil with a 174 mm cold bore, the cryocooled high temperature superconducting magnet successfully generated the total central field of 18.1 T in a 52 mm room temperature bore. As a next step, we start the collaboration with the National Institute for Materials Science for the new developmental works of a 30 T high temperature superconducting magnet and a 50 T-class hybrid magnet

  17. Superconductivity and its devices

    International Nuclear Information System (INIS)

    Forbes, D.S.

    1981-01-01

    Among the more important developments that are discussed are cryotrons, superconducting motors and generators, and high-field magnets. Cryotrons will create faster and more economical computer systems. Superconducting motors and generators will cost much less to build than conventional electric generators and cut fuel consumption. Moreover, high-field magnets are being used to confine plasma in connection with nuclear fusion. Superconductors have a vital role to play in all of these developments. Most importantly, though, are the magnetic properties of superconductivity. Superconducting magnets are an integral part of nuclear fusion. In addition, high-field magnets are necessary in the use of accelerators, which are needed to study the interactions between elementary particles

  18. Superconductive technologies for the Large Hadron collider at CERN

    CERN Document Server

    Rossi, L

    2000-01-01

    The Large Hadron Collider (LHC) project is the largest plant based on superconductivity and cryogenics: 27 km of tunnel filled with superconducting magnets and other equipment that will be kept at 1.9 K. The dipole magnets have to generate a minimum magnetic field of 8.3 T to allow collisions of proton beams at an energy of 14 TeV in the centre of mass. The construction of LHC started in 1997 at CERN in Geneva and required 10 years of research and development on fine- filament NbTi superconducting wires and cables, on magnet technology and on He-II refrigerators. In particular the project needs the production of about 1000 tons of high-homogeneity NbTi with current densities of more than 2000 A mm/sup -2/ at 9 T and 1.9 K, with tight control also of all other cable properties such as magnetization, interstrand resistance and copper resistivity. The paper describes the main dipole magnets and reviews the most significant steps in the research and development, focusing on the issues related to the conductor, to...

  19. Superconductivity

    CERN Document Server

    Poole, Charles P; Creswick, Richard J; Prozorov, Ruslan

    2014-01-01

    Superconductivity, Third Edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Widely used theoretical approaches are explained in detail. Topics of special interest include high temperature superconductors, spectroscopy, critical states, transport properties, and tunneling. This book covers the whole field of superconductivity from both the theoretical and the experimental point of view. This third edition features extensive revisions throughout, and new chapters on second critical field and iron based superconductors.

  20. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  1. Unconventional superconductivity in honeycomb lattice

    Directory of Open Access Journals (Sweden)

    P Sahebsara

    2013-03-01

    Full Text Available   ‎ The possibility of symmetrical s-wave superconductivity in the honeycomb lattice is studied within a strongly correlated regime, using the Hubbard model. The superconducting order parameter is defined by introducing the Green function, which is obtained by calculating the density of the electrons ‎ . In this study showed that the superconducting order parameter appears in doping interval between 0 and 0.5, and x=0.25 is the optimum doping for the s-wave superconductivity in honeycomb lattice.

  2. Basic Research Needs for Superconductivity. Report of the Basic Energy Sciences Workshop on Superconductivity, May 8-11, 2006

    Energy Technology Data Exchange (ETDEWEB)

    Sarrao, J.; Kwok, W-K; Bozovic, I.; Mazin, I.; Seamus, J. C.; Civale, L.; Christen, D.; Horwitz, J.; Kellogg, G.; Finnemore, D.; Crabtree, G.; Welp, U.; Ashton, C.; Herndon, B.; Shapard, L.; Nault, R. M.

    2006-05-11

    As an energy carrier, electricity has no rival with regard to its environmental cleanliness, flexibility in interfacing with multiple production sources and end uses, and efficiency of delivery. In fact, the electric power grid was named ?the greatest engineering achievement of the 20th century? by the National Academy of Engineering. This grid, a technological marvel ingeniously knitted together from local networks growing out from cities and rural centers, may be the biggest and most complex artificial system ever built. However, the growing demand for electricity will soon challenge the grid beyond its capability, compromising its reliability through voltage fluctuations that crash digital electronics, brownouts that disable industrial processes and harm electrical equipment, and power failures like the North American blackout in 2003 and subsequent blackouts in London, Scandinavia, and Italy in the same year. The North American blackout affected 50 million people and caused approximately $6 billion in economic damage over the four days of its duration. Superconductivity offers powerful new opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency. Superconductors are capable of carrying current without loss, making the parts of the grid they replace dramatically more efficient. Superconducting wires carry up to five times the current carried by copper wires that have the same cross section, thereby providing ample capacity for future expansion while requiring no increase in the number of overhead access lines or underground conduits. Their use is especially attractive in urban areas, where replacing copper with superconductors in power-saturated underground conduits avoids expensive new underground construction. Superconducting transformers cut the volume, weight, and losses of conventional transformers by a factor of two and do not require the contaminating and flammable transformer oils that violate urban safety

  3. Basic Research Needs for Superconductivity. Report of the Basic Energy Sciences Workshop on Superconductivity, May 8-11, 2006

    International Nuclear Information System (INIS)

    Sarrao, J.; Kwok, W-K; Bozovic, I.; Mazin, I.; Seamus, J. C.; Civale, L.; Christen, D.; Horwitz, J.; Kellogg, G.; Finnemore, D.; Crabtree, G.; Welp, U.; Ashton, C.; Herndon, B.; Shapard, L.; Nault, R. M.

    2006-01-01

    As an energy carrier, electricity has no rival with regard to its environmental cleanliness, flexibility in interfacing with multiple production sources and end uses, and efficiency of delivery. In fact, the electric power grid was named ?the greatest engineering achievement of the 20th century? by the National Academy of Engineering. This grid, a technological marvel ingeniously knitted together from local networks growing out from cities and rural centers, may be the biggest and most complex artificial system ever built. However, the growing demand for electricity will soon challenge the grid beyond its capability, compromising its reliability through voltage fluctuations that crash digital electronics, brownouts that disable industrial processes and harm electrical equipment, and power failures like the North American blackout in 2003 and subsequent blackouts in London, Scandinavia, and Italy in the same year. The North American blackout affected 50 million people and caused approximately $6 billion in economic damage over the four days of its duration. Superconductivity offers powerful new opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency. Superconductors are capable of carrying current without loss, making the parts of the grid they replace dramatically more efficient. Superconducting wires carry up to five times the current carried by copper wires that have the same cross section, thereby providing ample capacity for future expansion while requiring no increase in the number of overhead access lines or underground conduits. Their use is especially attractive in urban areas, where replacing copper with superconductors in power-saturated underground conduits avoids expensive new underground construction. Superconducting transformers cut the volume, weight, and losses of conventional transformers by a factor of two and do not require the contaminating and flammable transformer oils that violate urban safety

  4. Superconducting transition edge sensors and methods for design and manufacture thereof

    Science.gov (United States)

    Sadleir, John E. (Inventor)

    2013-01-01

    Methods for forming sensors using transition edge sensors (TES) and sensors therefrom are described. The method includes forming a plurality of sensor arrays includes at least one TES device. The TES device includes a TES device body, a first superconducting lead contacting a first portion of the TES device body, and a second superconducting lead contacting of a second portion of the TES device body, where the first and second superconducting leads separated on the TES device body by a lead spacing. The lead spacing can be selected to be different for at least two of the plurality of sensor arrays. The method also includes determining a transition temperature for each of the plurality of sensor arrays and generating a signal responsive to detecting a change in the electrical characteristics of one of the plurality of sensor arrays meeting a transition temperature criterion.

  5. 2017 Gordon Conference on Superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Chubukov, Andrey [Univ. of Minnesota, Twin Cities, MN (United States)

    2017-11-14

    The DOE award was for a 2017 Gordon Research conference on Superconductivity (GRC). The objective of GRC is to interchange the information about the latest theoretical and experimental developments in the area of superconductivity and to select most perspective directions for future research in this area.The goal of the Gordon Conference on Superconductivity is to present and discuss the latest results in the field of modern superconductivity, discuss new ideas and new directions of research in the area. It is a long-standing tradition of the Gordon conference on Superconductivity that the vast majority of participants are junior scientists. Funding for the conference would primarily be used to support junior researchers, particularly from under-represented groups. We had more 10 female speakers, some of them junior researchers, and some funding was used to support these speakers. The conference was held together with Gordon Research Seminar on Superconductivity, where almost all speakers and participants were junior scientists.

  6. Superconductivity and their applications

    OpenAIRE

    Roque, António; Sousa, Duarte M.; Fernão Pires, Vítor; Margato, Elmano

    2017-01-01

    Trabalho apresentado em International Conference on Renewable Energies and Power Quality (ICREPQ’17), 4 a 6 de Abril de 2017, Málaga, Espanha The research in the field of superconductivity has led to the synthesis of superconducting materials with features that allow you to expand the applicability of this kind of materials. Among the superconducting materials characteristics, the critical temperature of the superconductor is framing the range and type of industrial applications that can b...

  7. Report on the achievements in fiscal 1999. Research and development on a basic technology to apply superconductivity (Research and development on a basic technology to apply superconductivity); 1999 nendo chodendo oyo kiban gijutsu kenkyu kaihatsu seika hokokusho. Chodendo oyo kiban gijutsu kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-01

    The development of a basic technology to improve superconductivity characteristics has performed (1) studies on the high-temperature superconductivity mechanism, (2) studies on the critical current mechanism, and (3) search for materials. In Item (1), composition and temperature dependence were investigated by measuring superconductivity gap and change in the electron state of pseudo gap using photo-electron spectra and Raman scattering spectra. In Item (2), magnetic flux behavior in the vicinity of the irreversible line was investigated on magnetic flux dynamics of Bi2212 by measuring magnetic resistance and magnetization. High viscosity condition having strong magnetic flux liquid zone was discovered. In Item (3), Sr was used in place of Ba as the constituting element, and several new mercury-based superconductors were synthesized successfully by using the high pressure synthesizing method. In developing superconductive bulk materials and wire materials, elucidation was given on (1) an element technology for high magnetic power bulk materials, (2) an element technology for high critical temperature bulk materials, (3) a fundamental technology for manufacturing next generation wire materials, (4) a fundamental technology for manufacturing next generation large current conductors, and (5) growth mechanism in wire material crystals. Development of laminating and processing technologies for superconductive materials has worked on (1) a single crystal substrate technology, (2) a thin film lamination technology, (3) a standard bonding technology, (4) an advanced bonding technology, and (5) a thin film and bond evaluation technology. (NEDO)

  8. Superconducting wind turbine generators

    International Nuclear Information System (INIS)

    Abrahamsen, A B; Seiler, E; Zirngibl, T; Andersen, N H; Mijatovic, N; Traeholt, C; Pedersen, N F; Oestergaard, J; Noergaard, P B

    2010-01-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  9. Purification of condenser water in thermal power station by superconducting magnetic separation

    International Nuclear Information System (INIS)

    Ha, D.W.; Kwon, J.M.; Baik, S.K.; Lee, Y.J.; Han, K.S.; Ko, R.K.; Sohn, M.H.; Seong, K.C.

    2011-01-01

    Magnetic separation using cryo-cooled Nb-Ti superconducting magnet was applied for the purification of condenser water. Iron oxides in condenser water were effectively removed by superconducting magnetic separation. The effect of magnetic field strength and filter size was determined. Thermal power station is made up of a steam turbine and a steam condenser which need a lot of water. The water of steam condenser should be replaced, since scales consisting of iron oxide mainly are accumulated on the surface of condenser pipes as it goes. Superconducting high gradient magnetic separation (HGMS) system has merits to remove paramagnetic substance like iron oxides because it can generate higher magnetic field strength than electromagnet or permanent magnet. In this paper, cryo-cooled Nb-Ti superconducting magnet that can generate up to 6 T was used for HGMS systems. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The result of X-ray analysis showed contaminants were mostly α-Fe 2 O 3 (hematite) and γ-Fe 2 O 3 (maghemite). The higher magnetic field was applied up to 6 T, the more iron oxides were removed. As the wire diameter of magnetic filter decreased, the turbidity removal of the sample was enhanced.

  10. Superconducting properties of a copper-ternary alloy

    International Nuclear Information System (INIS)

    Sharma, R.G.; Aleksivskii, N.E.

    1975-01-01

    The superconducting properties of a copper-ternary alloy of the type Cu 93 Nb 5 Sn 2 , subjected to a variety of mechanical and heat treatments, are discussed. The as-cast alloy does not turn superconducting down to 4.5K; but the cold-work and subsequent prescribed heat treatments are found to raise the transition temperature Tsub(c) to values as high as 18.1K and the critical current density Jsub(c) (of the Nb 3 Sn formed during annealing) to a value of 3.6x10 5 Acm -2 (at 4.2K and 30kOe). Various possibilities to improve Jsub(c) of this alloy to still higher values are discussed. The as-cast alloy is ductile, easy to draw, and economical from a technical point of view, and the annealed wires and strips are flexible enough for winding. (author)

  11. Superconductivity from magnetic elements under high pressure

    International Nuclear Information System (INIS)

    Shimizu, Katsuya; Amaya, Kiichi; Suzuki, Naoshi; Onuki, Yoshichika

    2006-01-01

    Can we expect the appearance of superconductivity from magnetic elements? In general, superconductivity occurs in nonmagnetic metal at low temperature and magnetic impurities destroy superconductivity; magnetism and superconductivity are as incompatible as oil and water. Here, we present our experimental example of superconducting elements, iron and oxygen. They are magnetic at ambient pressure, however, they become nonmagnetic under high pressure, then superconductor at low temperature. What is the driving force of the superconductivity? Our understanding in the early stages was a simple scenario that the superconductive state was obtained as a consequence of an emergence of the nonmagnetic states. In both cases, we may consider another scenario for the appearance of superconductivity; the magnetic fluctuation mechanism in the same way as unconventional superconductors

  12. Superconducted tour

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1988-09-15

    Superconductivity - the dramatic drop in electrical resistance in certain materials at very low temperatures - has grown rapidly in importance over the past two or three decades to become a key technology for high energy particle accelerators. It was in this setting that a hundred students and 15 lecturers met in Hamburg in June for a week's course on superconductivity in particle accelerators, organized by the CERN Accelerator School and the nearby DESY Laboratory.

  13. Superconductivity: Phenomenology

    International Nuclear Information System (INIS)

    Falicov, L.M.

    1988-08-01

    This document discusses first the following topics: (a) The superconducting transition temperature; (b) Zero resistivity; (c) The Meissner effect; (d) The isotope effect; (e) Microwave and optical properties; and (f) The superconducting energy gap. Part II of this document investigates the Ginzburg-Landau equations by discussing: (a) The coherence length; (b) The penetration depth; (c) Flux quantization; (d) Magnetic-field dependence of the energy gap; (e) Quantum interference phenomena; and (f) The Josephson effect

  14. Design study of superconducting sextupole magnet using HTS coated conductor for neutron-focusing device

    International Nuclear Information System (INIS)

    Tosaka, T.; Koyanagi, K.; Ono, M.; Kuriyama, T.; Watanabe, I.; Tsuchiya, K.; Suzuki, J.; Adachi, T.; Shimizu, H.M.

    2006-01-01

    We performed a design study of sextupole magnet using high temperature superconducting (HTS) wires. The sextupole magnet is used as a focusing lens for neutron-focusing devices. A neutron-focusing device is desired to have a large aperture and a high magnetic field gradient of G, where G = 2B/r 2 , B is the magnetic field and r is a distance from the sextupole magnet axis. Superconducting magnets offer promising prospects to meet the demands of a neutron-focusing device. Recently NbTi coils of low temperature superconducting (LTS) have been developed for a sextupole magnet with a 46.8 mm aperture. The maximum magnetic field gradient G of this magnet is 9480 T/m 2 at 4.2 K and 12,800 T/m 2 at 1.8 K. On the other hand, rapid progress on second generation HTS wire has been made in increasing the performance of critical current and in demonstrating a long length. The second generation HTS wire is referred to as coated conductor. It consists of tape-shaped base upon which a thin coating of superconductor, usually YBCO, is deposited or grown. This paper describes a design study of sextupole magnet using coated conductors

  15. Modal bifurcation in a high-Tc superconducting levitation system

    International Nuclear Information System (INIS)

    Taguchi, D; Fujiwara, S; Sugiura, T

    2011-01-01

    This paper deals with modal bifurcation of a multi-degree-of-freedom high-T c superconducting levitation system. As modeling of large-scale high-T c superconducting levitation applications, where plural superconducting bulks are often used, it can be helpful to consider a system constituting of multiple oscillators magnetically coupled with each other. This paper investigates nonlinear dynamics of two permanent magnets levitated above high-T c superconducting bulks and placed between two fixed permanent magnets without contact. First, the nonlinear equations of motion of the levitated magnets were derived. Then the method of averaging was applied to them. It can be found from the obtained solutions that this nonlinear two degree-of-freedom system can have two asymmetric modes, in addition to a symmetric mode and an antisymmetric mode both of which also exist in the linearized system. One of the backbone curves in the frequency response shows a modal bifurcation where the two stable asymmetric modes mentioned above appear with destabilization of the antisymmetric mode, thus leading to modal localization. These analytical predictions have been confirmed in our numerical analysis and experiments of free vibration and forced vibration. These results, never predicted by linear analysis, can be important for application of high-T c superconducting levitation systems.

  16. Development of scaling rules for Rutherford type superconducting cables

    International Nuclear Information System (INIS)

    Royet, J.M.; Scanlan, R.M.

    1991-01-01

    During the R and D phase of the Superconducting Supercollider (SSC) program, LBL was responsible for establishing the parameters for cables used in SSC dipole and quadrupole magnets. In addition, LBL has collaborated with Fermi National Accelerator Laboratory on the design and fabrication of a new cable for use in the Low Beta Quadrupoles. As a result of the development work on these and other cables, we have arrived a set of scaling rules which provide guidelines for choosing the parameters for a wide range of superconducting cables. These parameters include strand size, strand number, keystone angle, percent compaction, cable pitch and compacted cable dimensions. In addition, we have defined the tolerance ranges for the key cable manufacturing parameters such as mandrel size and shape, strand tension, and Turkshead temperature control. In this paper, the authors present the results on cables ranging from 8 strands to 36 strands of 0.65mm wire and from 8 strands to 30 strands of 0.8mm wire. The authors use these results to demonstrate the application of the scaling rules for Rutherford-type cable

  17. Development of scaling rules for Rutherford type superconducting cables

    International Nuclear Information System (INIS)

    Royet, J.M.; Scanlan, R.M.

    1990-09-01

    During the R ampersand D phase of the Superconducting Supercollider (SSC) program, LBL was responsible for establishing the parameters for cables used in SSC dipole and quadrupole magnets. In addition, the design and fabrication of a new cable for use in the Low Beta Quadrupoles. As a result of the development work on these and other cables, we have arrived a set of scaling rules which provide guidelines for choosing the parameters for a wide range of superconducting cables. These parameters include strand size, strand number, keystone angle, percent compaction, cable pitch and compacted cable dimensions. In addition, we have defined the tolerance ranges for the key cable manufacturing parameters such as mandrel size and shape, stand tension, and Turkshead temperature control. In this paper, we present the results on cables ranging from 8 strands to 36 strands of 0.65mm wire and from 8 strands to 30 strands of 0.8mm wire. We use these results to demonstrate the application of the scaling rules for Rutherford-type cable

  18. Quench Property of Twisted-Pair MgB$_2$ Superconducting Cables in Helium Gas

    CERN Document Server

    Spurrell, J; Falorio, I; Pelegrin, J; Ballarino, A; Yang, Y

    2015-01-01

    CERN's twisted-pair superconducting cable is a novel design which offers filament transposition, low cable inductance and is particularly suited for tape conductors such as 2G YBCO coated conductors, Ag-sheathed Bi2223 tapes and Ni/Monel-sheathed MgB2 tapes. A typical design of such twistedpair cables consists of multiple superconducting tapes intercalated with thin copper tapes as additional stabilizers. The copper tapes are typically not soldered to the superconducting tapes so that sufficient flexibility is retained for the twisting of the tape assembly. The electrical and thermal contacts between the copper and superconducting tapes are an important parameter for current sharing, cryogenic stability and quench propagation. Using an MgB2 twisted-pair cable assembly manufactured at CERN, we have carried out minimum quench energy (MQE) and propagation velocity (vp) measurements with point-like heat deposition localized within a tape. Furthermore, different contacts between the copper and superconductor aroun...

  19. Select problems of the electrodynamics of superconducting weak-coupled systems

    International Nuclear Information System (INIS)

    Belenov, E.M.; Vedeneev, S.I.; Uskov, A.V.

    1988-01-01

    The interaction of currents in superconducting Josephson elements irradiated by electromagnetic fields in a cavity and a waveguide is considered theoretically. The possibility of using weak-coupled systems to implement stimulated emission oscillators tunable over a broad range from 10 10 to 10 13 Hz is investigated. The properties of a superconducting point contact for use as a nonlinear element in a reference frequency circuit from the microwave to the optical ranges are investigated theoretically. The possibility of frequency synthesis by means of a single nonlinear element from the microwave range to the optical range is demonstrated together with the capacity for precision laser frequency measurements. The noise aspects of using superconducting elements for laser frequency measurements are investigated

  20. Introduction to superconductivity

    CERN Document Server

    Darriulat, Pierre

    1998-01-01

    The lecture series will address physicists, such as particle and nuclear physicists, familiar with non-relativistic quantum mechanics but not with solid state physics. The aim of this introduction to low temperature superconductivity is to give sufficient bases to the student for him/her to be able to access the scientific literature on this field. The five lectures will cover the following topics : 1. Normal metals, free electron gas, chambers equation. 2. Cooper pairs, the BCS ground state, quasi particle excitations. 3. DC superconductivity, Meissner state, dirty superconductors.4. Self consistent approach, Ginsburg Landau equations, Abrikosov fluxon lattice. 5. Josephson effects, high temperature superconductivity.

  1. Superconducting properties of (Nb,Ta)3Sn wires fabricated by the bronze process

    International Nuclear Information System (INIS)

    Suenaga, M.; Aihara, K.; Kaiho, K.; Luhman, T.S.

    1979-01-01

    Measurements of the superconducting critical temperature T/sub c/, critical current density, J/sub c/ (8 3 Sn monofilamentary wires. Ta content in the Nb 3 Sn compound was varied by alloying the Nb core prior to a reaction heat treatment. Core compositions were 0, 3, 7, 10, and 20 wt% Ta and heat treatments for the reaction were 16, 64, and 120 h at 725 0 C. For the 120 h heat treatment T/sub c/ decreased monotonically with Ta content from 17.5 to 15.7K while H/sub c2/ increased from 19.8 to 24.6 T. With increasing Ta content J/sub c/ (16 T) increased from 0.7 x 10 5 A/cm 2 to a maximum value of 1.3 x 10 5 at 7 wt% Ta. Further increases in the Ta content produced a decrease in J/sub c/(16 T). At 10 T J/sub c/ decreased with increasing Ta content. An important aspect of this work is the observation that alloying with Ta did not hinder wire ductility during drawing. It appears therefore that the improvements in J/sub c/(16 T) can be incorporated into commercially manufactured conductors

  2. Progress in DOE high temperature superconductivity electric power applications program

    International Nuclear Information System (INIS)

    Daley, J.G.; Sheahn, T.P.

    1992-01-01

    The Department of Energy (DOE) leads national R and D effort to develop US industry's capability to produce a wide range of advanced energy-efficient electric power products. The immediate need is to make high temperature superconductivity (HTS) wire. Wire developers at the DOE National laboratories are working wit industrial partners toward this objective. In this paper, the authors describe the progress to date, citing both the difficulties associated with making wire from these ceramic materials, and achievements at several organizations. Results for progress over the next five years are stated

  3. The development of superconducting equipment

    CERN Document Server

    Ueda, T; Hiue, H

    2003-01-01

    Fuji Electric has been developing various types of superconducting equipment for over a quarter of a century. This paper describes the development results achieved for superconducting equipment and especially focuses on large-capacity current leads and superconducting transmission systems, the development of which is being promoted for application to the field of nuclear fusion. High temperature superconductor (HTS) is becoming the mainstream in the field of superconductivity, and the HTS floating coil and conduction-cooled HTS transformed are also introduced as recent developments for devices that utilize this technology. (author)

  4. Multifilamentary superconducting (NbTa)-Sn composite wire by solid-liquid reaction for possible application above 20 tesla

    International Nuclear Information System (INIS)

    Hong, M.; Hull, G.W. Jr.; Fuchs, E.O.; Holthuis, J.T.

    1983-01-01

    Nb alloyed with Ta was employed in fabricating multifilamentary composite wires of (NbTa)-Sn using the liquid-infiltration process. The superconducting A15 phase was formed with subsequent heat treatments at 800-950 0 C by the solid-liquid reaction. High inductive Tsub(c)'s of 18.2 K with sharp transition width ( 4 A/cm 2 at 2O T and 4.2 K were obtained. It was found that 2 wt.% Ta in the Nb was sufficient in the enhancement of the overall Jsub(c) at the high fields and in increasing the Hsub(c2) (4.2 K) to 25 T. (Auth.)

  5. Multifilamentary superconducting (NbTa)-Sn composite wire by solid-liquid reaction for possible application above 20 tesla

    International Nuclear Information System (INIS)

    Hong, M.; Hull, G.W. Jr.; Fuchs, E.O.; Holthuis, J.T.

    1983-01-01

    Nb alloyed with Ta was employed in fabricating multifilamentary composite wires of (NbTa)-Sn using the liquid-infiltration process. The superconducting A15 phase was formed with subsequent heat treatments at 800-950 0 C by the solid-liquid reaction. High inductive Tsub(c)'s of 18.2 K with sharp transition width ( 4 A/cm 2 at 20 T and 4.2 K were obtained. It was found that 2 wt.% Ta in the Nb was sufficient in the enhancement of the overall Jsub(c) at the high fields and in increasing the Hsub(c2) (4.2 K) to 25 T. (orig.)

  6. Materials and mechanisms of hole superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, J.E., E-mail: jhirsch@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319 (United States)

    2012-01-15

    We study the applicability of the model of hole superconductivity to materials. Both conventional and unconventional materials are considered. Many different classes of materials are discussed. The theory is found suitable to describe all of them. No other theory of superconductivity can describe all these classes of materials. The theory of hole superconductivity proposes that there is a single mechanism of superconductivity that applies to all superconducting materials. This paper discusses several material families where superconductivity occurs and how they can be understood within this theory. Materials discussed include the elements, transition metal alloys, high T{sub c} cuprates both hole-doped and electron-doped, MgB{sub 2}, iron pnictides and iron chalcogenides, doped semiconductors, and elements under high pressure.

  7. Molybdenum-rhenium superconducting suspended nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Mohsin; Christopher Hudson, David; Russo, Saverio [Centre for Graphene Science, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF (United Kingdom)

    2014-06-09

    Suspended superconducting nanostructures of MoRe 50%/50% by weight are fabricated employing commonly used fabrication steps in micro- and nano-meter scale devices followed by wet-etching with Hydro-fluoric acid of a SiO{sub 2} sacrificial layer. Suspended superconducting channels as narrow as 50 nm and length 3 μm have a critical temperature of ≈6.5 K, which can increase by 0.5 K upon annealing at 400 °C. A detailed study of the dependence of the superconducting critical current and critical temperature upon annealing and in devices with different channel widths reveals that desorption of contaminants is responsible for the improved superconducting properties. These findings pave the way for the development of superconducting electromechanical devices using standard fabrication techniques.

  8. Superconducting RF activities at Cornell University

    International Nuclear Information System (INIS)

    Kirchgessner, J.; Moffat, D.; Padamsee, H.; Rubin, D.; Sears, J.; Shu, Q.S.

    1990-01-01

    This paper outlines the RF superconductivity research and development work that has taken place at Cornell Laboratory of Nuclear Studies over the past years. The work that has been performed since the last RF superconductivity workshop is emphasized together with a discussion of the direction of future efforts. Past work is summarized first, focusing on research and development activities in the area of RF superconductivity. Superconducting TeV linear collider is then discussed focusing on the application of superconducting RF to a future TeV linear collider. Linear collider structure development is then described centering on the development of a simpler (thereby cheaper) structure for a TeV linear collider. B-factory with superconducting RF is outlined focusing on the formulation of a conceptual design for a B-factory. B-factory structure development is discussed in relation to the advancement in the capability of SC cavities to carry beam currents of several amperes necessary for a high luminosity storage ring. High gradients are discussed as the key to the realization of a high energy superconducting linac or a superconducting RF B-factory. (N.K.)

  9. Mechanical characterization of journal superconducting magnetic bearings: stiffness, hysteresis and force relaxation

    International Nuclear Information System (INIS)

    Cristache, Cristian; Valiente-Blanco, Ignacio; Diez-Jimenez, Efren; Alvarez-Valenzuela, Marco Antonio; Perez-Diaz, Jose Luis; Pato, Nelson

    2014-01-01

    Superconducting magnetic bearings (SMBs) can provide stable levitation without direct contact between them and a magnetic source (typically a permanent magnet). In this context, superconducting magnetic levitation provides a new tool for mechanical engineers to design non-contact mechanisms solving the tribological problems associated with contact at very low temperatures. In the last years, different mechanisms have been proposed taking advantage of superconducting magnetic levitation. Flywheels, conveyors or mechanisms for high-precision positioning. In this work the mechanical stiffness of a journal SMBs have been experimentally studied. Both radial and axial stiffness have been considered. The influence of the size and shape of the permanent magnets (PM), the size and shape of the HTS, the polarization and poles configuration of PMs of the journal SMB have been studied experimentally. Additionally, in this work hysteresis behavior and force relaxation are considered because they are essential for mechanical engineer when designing bearings that hold levitating axles.

  10. Superconducting materials for large scale applications

    International Nuclear Information System (INIS)

    Scanlan, Ronald M.; Malozemoff, Alexis P.; Larbalestier, David C.

    2004-01-01

    Significant improvements in the properties of superconducting materials have occurred recently. These improvements are being incorporated into the latest generation of wires, cables, and tapes that are being used in a broad range of prototype devices. These devices include new, high field accelerator and NMR magnets, magnets for fusion power experiments, motors, generators, and power transmission lines. These prototype magnets are joining a wide array of existing applications that utilize the unique capabilities of superconducting magnets:accelerators such as the Large Hadron Collider, fusion experiments such as ITER, 930 MHz NMR, and 4 Tesla MRI. In addition, promising new materials such as MgB2 have been discovered and are being studied in order to assess their potential for new applications. In this paper, we will review the key developments that are leading to these new applications for superconducting materials. In some cases, the key factor is improved understanding or development of materials with significantly improved properties. An example of the former is the development of Nb3Sn for use in high field magnets for accelerators. In other cases, the development is being driven by the application. The aggressive effort to develop HTS tapes is being driven primarily by the need for materials that can operate at temperatures of 50 K and higher. The implications of these two drivers for further developments will be discussed. Finally, we will discuss the areas where further improvements are needed in order for new applications to be realized

  11. Frontiers in Superconducting Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Superconducting Materials gives a state-of-the-art report of the most important topics of the current research in superconductive materials and related phenomena. It comprises 30 chapters written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students. It also addresses electronic and electrical engineers. Even non-specialists interested in superconductivity might find some useful answers.

  12. Superconductivity in the actinides

    International Nuclear Information System (INIS)

    Smith, J.L.; Lawson, A.C.

    1985-01-01

    The trends in the occurrence of superconductivity in actinide materials are discussed. Most of them seem to show simple transition metal behavior. However, the superconductivity of americium proves that the f electrons are localized in that element and that ''actinides'' is the correct name for this row of elements. Recently the superconductivity of UBe 13 and UPt 3 has been shown to be extremely unusual, and these compounds fall in the new class of compounds now known as heavy fermion materials

  13. Superconducting rotating machines

    International Nuclear Information System (INIS)

    Smith, J.L. Jr.; Kirtley, J.L. Jr.; Thullen, P.

    1975-01-01

    The opportunities and limitations of the applications of superconductors in rotating electric machines are given. The relevant properties of superconductors and the fundamental requirements for rotating electric machines are discussed. The current state-of-the-art of superconducting machines is reviewed. Key problems, future developments and the long range potential of superconducting machines are assessed

  14. Status of superconducting power transformer development

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.C.; McConnell, B.W.; Mehta, S.P. [and others

    1996-03-01

    Development of the superconducting transformer is arguably the most difficult of the ac power applications of superconductivity - this is because of the need for very low ac losses, adequate fault and surge performance, and the rigors of the application environment. This paper briefly summarizes the history of superconducting transformer projects, reviews the key issues for superconducting transformers, and examines the status of HTS transformer development. Both 630-kVA, three-phase and 1-MVA single phase demonstration units are expected to operate in late 1996. Both efforts will further progress toward the development of economical and performance competitive superconducting transformers.

  15. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  16. Quenches in large superconducting magnets

    International Nuclear Information System (INIS)

    Eberhard, P.H.; Alston-Garnjost, M.; Green, M.A.; Lecomte, P.; Smits, R.G.; Taylor, J.D.; Vuillemin, V.

    1977-08-01

    The development of large high current density superconducting magnets requires an understanding of the quench process by which the magnet goes normal. A theory which describes the quench process in large superconducting magnets is presented and compared with experimental measurements. The use of a quench theory to improve the design of large high current density superconducting magnets is discussed

  17. Development of superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2013-01-01

    In this paper, the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors; one is based on high temperature superconductors......; and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are, however, not without their challenges. The superconductors have to be cooled down to somewhere...

  18. Development of Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2012-01-01

    In this paper the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors (LTS); one is based on high temperature superconductors...... (HTS); and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are however not without their challenges. The superconductors have to be cooled down...

  19. Superconducting fault current-limiter with variable shunt impedance

    Science.gov (United States)

    Llambes, Juan Carlos H; Xiong, Xuming

    2013-11-19

    A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

  20. Superconducting magnetic energy storage and superconducting self-supplied electromagnetic launcher

    Science.gov (United States)

    Ciceron, Jérémie; Badel, Arnaud; Tixador, Pascal

    2017-10-01

    Superconductors can be used to build energy storage systems called Superconducting Magnetic Energy Storage (SMES), which are promising as inductive pulse power source and suitable for powering electromagnetic launchers. The second generation of high critical temperature superconductors is called coated conductors or REBCO (Rare Earth Barium Copper Oxide) tapes. Their current carrying capability in high magnetic field and their thermal stability are expanding the SMES application field. The BOSSE (Bobine Supraconductrice pour le Stockage d'Energie) project aims to develop and to master the use of these superconducting tapes through two prototypes. The first one is a SMES with high energy density. Thanks to the performances of REBCO tapes, the volume energy and specific energy of existing SMES systems can be surpassed. A study has been undertaken to make the best use of the REBCO tapes and to determine the most adapted topology in order to reach our objective, which is to beat the world record of mass energy density for a superconducting coil. This objective is conflicting with the classical strategies of superconducting coil protection. A different protection approach is proposed. The second prototype of the BOSSE project is a small-scale demonstrator of a Superconducting Self-Supplied Electromagnetic Launcher (S3EL), in which a SMES is integrated around the launcher which benefits from the generated magnetic field to increase the thrust applied to the projectile. The S3EL principle and its design are presented. Contribution to the topical issue "Electrical Engineering Symposium (SGE 2016)", edited by Adel Razek

  1. Stabilized superconducting materials and fabrication process

    International Nuclear Information System (INIS)

    Chevallier, B.; Dance, J.M.; Etourneau, J.; Lozano, L.; Tressaud, A.; Tournier, R.; Sulpice, A.; Chaussy, J.; Lejay, P.

    1989-01-01

    Superconducting ceramics are fluorinated at a temperature ≤ 120 0 C. Are also claimed new superconducting materials with a fluorine concentration gradient decreasing from the surface to the core. Superconductivity is stabilized and/or improved [fr

  2. Superconductivity in MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Muranaka, Takahiro; Akimitsu, Jun [Aoyama Gakuin Univ., Kanagawa (Japan). Dept. of Physics and Mathematics

    2011-07-01

    We review superconductivity in MgB{sub 2} in terms of crystal and electronic structure, electron-phonon coupling, two-gap superconductivity and application. Finally, we introduce the development of new superconducting materials in related compounds. (orig.)

  3. Superconducting materials and magnets

    International Nuclear Information System (INIS)

    1991-04-01

    The Technical Committee Meeting on Superconducting Materials and Magnets was convened by the IAEA and held by invitation of the Japanese government on September 4-6, 1989 in Tokyo. The meeting was hosted by the National Research Institute for Metals. Topics of the conference related to superconducting magnets and technology with particular application to fusion and the superconducting supercollider. Technology using both high and low-temperature superconductors was discussed. This document is a compendium of the papers presented at the meeting. Refs, figs and tabs

  4. Basic study of HTS magnet using 2G wires for maglev train

    International Nuclear Information System (INIS)

    Ogata, M.; Miyazaki, Y.; Hasegawa, H.; Sasakawa, T.; Nagashima, K.

    2010-01-01

    There are several advantages by applying a high-temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the I c measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of I c characteristics for the small race track-shaped superconducting coil.

  5. Preliminary study of HTS magnet using 2G wires for maglev train

    International Nuclear Information System (INIS)

    Ogata, Masafumi; Miyazaki, Yoshiki; Hasegawa, Hitoshi; Sasakawa, Takashi; Nagashima, Ken

    2010-01-01

    There are several advantages by applying a high temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the I c measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of I c characteristics for the small race track-shaped superconducting coil.

  6. Basic study of HTS magnet using 2G wires for maglev train

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, M., E-mail: ogata@rtri.or.j [Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan); Miyazaki, Y.; Hasegawa, H.; Sasakawa, T.; Nagashima, K. [Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji-shi, Tokyo 185-8540 (Japan)

    2010-11-01

    There are several advantages by applying a high-temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the I{sub c} measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of I{sub c} characteristics for the small race track-shaped superconducting coil.

  7. Preliminary study of HTS magnet using 2G wires for maglev train

    Energy Technology Data Exchange (ETDEWEB)

    Ogata, Masafumi; Miyazaki, Yoshiki; Hasegawa, Hitoshi; Sasakawa, Takashi; Nagashima, Ken, E-mail: ogata@rtri.or.j [Railway Technical Research Institute, Hikari-cho 2-8-38, Kokubunji-shi, Tokyo (Japan)

    2010-06-01

    There are several advantages by applying a high temperature superconducting wire to an on-board superconducting magnet for the maglev train. At first, an increase of thermal capacity of superconducting coils contributes a stability of the superconducting state of the coils. In addition, a reliability of superconducting magnet improves by simplification of the magnet structure. And the weight of the superconducting magnet and the energy consumption of the on-board cryocooler will decrease. Therefore, we examined the possibility on application of the 2G wire with a high critical current density in a high magnetic field. We performed numerical analysis regarding the weight of a superconducting magnet and the energy consumption of an on-board cryocooler in consideration of the characteristics of the 2G wire. Furthermore, we have carried out the I{sub c} measurement for the commercial 2G wires under various experimental conditions such as temperature, magnetic field strength and angle. We also performed the trial manufacture and evaluation of I{sub c} characteristics for the small race track-shaped superconducting coil.

  8. Macroscopic Quantum Tunneling in Superconducting Junctions of β-Ag2Se Topological Insulator Nanowire.

    Science.gov (United States)

    Kim, Jihwan; Kim, Bum-Kyu; Kim, Hong-Seok; Hwang, Ahreum; Kim, Bongsoo; Doh, Yong-Joo

    2017-11-08

    We report on the fabrication and electrical transport properties of superconducting junctions made of β-Ag 2 Se topological insulator (TI) nanowires in contact with Al superconducting electrodes. The temperature dependence of the critical current indicates that the superconducting junction belongs to a short and diffusive junction regime. As a characteristic feature of the narrow junction, the critical current decreases monotonously with increasing magnetic field. The stochastic distribution of the switching current exhibits the macroscopic quantum tunneling behavior, which is robust up to T = 0.8 K. Our observations indicate that the TI nanowire-based Josephson junctions can be a promising building block for the development of nanohybrid superconducting quantum bits.

  9. Influence of pulse electric current on structure and superconducting properties of high temperature superconductor

    International Nuclear Information System (INIS)

    Rajchenko, A.I.; Flis, A.A.; Chernenko, L.I.; Kryuchkova, N.I.

    1998-01-01

    The influence of high-density pulse current treatment at room temperature on structure and superconducting properties of HTSC Y Ba 2 Cu 3 O x ceramics is studied. The structures of the samples are found to undergo appreciable changes as the density of pulse current is gradually increased from its minimum value; as a certain threshold value is attained, there occurs a melting-off of coarse grains with a partial destroying of intergrain contact areas followed by superconductivity loss. A further increase in the treatment current density results in a restoration of the superconducting properties probably due to the occurrence of aligned-with-current superconducting bridges between the melted-off grains. The superconducting transition temperature in the samples does not charge but subsequent thermal treatment causes this temperature to increase

  10. Development of superconducting ship propulsion system

    International Nuclear Information System (INIS)

    Sakuraba, Junji; Mori, Hiroyuki; Hata, Fumiaki; Sotooka, Koukichi

    1991-01-01

    When we plan displacement-type monohull high speed vessels, it is difficult to get the hull form with the wave-making resistance minimum, because the stern shape is restricted by arrangement of propulsive machines and shafts. A small-sized and light-weight propulsive machines will reduce the limit to full form design. Superconducting technology will have capability of realizing the small-sized and light-weight propulsion motor. The superconducting electric propulsion system which is composed of superconducting propulsion motors and generators, seems to be an ideal propulsion system for future vehicles. We have constructed a 480 kW superconducting DC homopolar laboratory test motor for developing this propulsion system. The characteristic of this motor is that it has a superconducting field winding and a segmented armature drum. The superconducting field winding which operates in the persistent current mode, is cooled by a condensation heat exchanger and helium refigerating system built into the cryostat of the superconducting field winding. The operating parameters of this motor agreed well with the design parameters. Using the design concepts of this motor, we have conceptually designed a 150,000-200,000 PS superconducting electric propulsive system for a displacement-type monohull high speed ship. (author)

  11. Superconductivity Engineering and Its Application for Fusion 3.Superconducting Technology as a Gateway to Future Technology

    Science.gov (United States)

    Asano, Katsuhiko

    Hopes for achieving a new source of energy through nuclear fusion rest on the development of superconducting technology that is needed to make future equipments more energy efficient as well as increase their performance. Superconducting technology has made progress in a wide variety of fields, such as energy, life science, electronics, industrial use and environmental improvement. It enables the actualization of equipment that was unachievable with conventional technology, and will sustain future “IT-Based Quality Life Style”, “Sustainable Environmental” and “Advanced Healthcare” society. Besides coil technology with high magnetic field performance, superconducting electoronics or device technology, such as SQUID and SFQ-circuit, high temperature superconducting material and advanced cryogenics technology might be great significance in the history of nuclear fusion which requires so many wide, high and ultra technology. Superconducting technology seems to be the catalyst for a changing future society with nuclear fusion. As society changes, so will superconducting technology.

  12. Localized excitations in superconducting point contacts: probing the Andreev doublet

    International Nuclear Information System (INIS)

    Bretheau, L.

    2013-01-01

    The Josephson effect describes the coherent coupling between superconductors and the resulting supercurrent. Microscopically, it arises from the existence of discrete quasiparticle states, localized at the weak link, the Andreev bound states. They come in doublets in each conduction channel of the weak link, with energies symmetric about the Fermi energy and opposite supercurrents. Each Andreev doublet gives rise to four states: the ground state |-> and the excited state |+>, with even parity, and the excited odd states |↑> and |↓>. Is it possible to address and control Andreev doublets? This thesis describes two sets of experiments designed to answer this question using the most basic Josephson element, a one-atom contact between two superconducting electrodes. In a first experiment, we have observed and characterized the excited odd states |↑> and |↓>. As expected for a spin-degenerate system, they do not carry supercurrent. In this experiment the excitation was uncontrolled and resulted from trapping of spurious quasiparticles. We have measured the lifetime of the odd states: under some condition, it is found to exceed 100 μs. The second experiment is a photon-absorption spectroscopy of the Andreev doublet. It was performed by using a Josephson junction as an integrated on-chip microwave emitter and detector. The observed Andreev transitions correspond to excitation from the ground state |->to the excited even state |+>, and are well accounted for by our quantum model. This result opens the way to coherent manipulation of this two level system. The direct observation of the excited Andreev state, either by quasiparticle-injection or photon-absorption, strongly supports the mesoscopic theory of the Josephson effect. It shows that in addition to the phase difference, each channel of a Josephson weak link possesses an internal fermionic degree of freedom. It could be used to code information in a novel type of superconducting qubit. (author) [fr

  13. Superconductivity in doped insulators

    International Nuclear Information System (INIS)

    Emery, V.J.; Kivelson, S.A.

    1995-01-01

    It is shown that many synthetic metals, including high temperature superconductors are ''bad metals'', with such a poor conductivity that the usual meanfield theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. It is argued that the supression of a first order phase transition (phase separation) by the long-range Coulomb interaction leads to high temperature superconductivity accompanied by static or dynamical charge inhomogeneIty. Evidence in support of this picture for high temperature superconductors is described

  14. Development of superconducting equipment for fusion device

    International Nuclear Information System (INIS)

    Konno, Masayuki; Ueda, Toshio; Hiue, Hisaaki; Ohgushi, Kouzou

    1993-01-01

    At Fuji Electric Co., Ltd., the development of superconductivity was started from 1960, and superconducting equipment for fusion device has been developed for ten years. The superconducting equipment, which is developed for fusion by Fuji Electric Co., Ltd., are able to be grouped in three categories which are current lead, superconducting coil and superconducting bus-line. The current lead is an electrical feeder between a superconducting coil and an electrical power supply. The rated current of developed current lead is 30kA at continuous use and 100kA at short time use respectively. The advanced disk type coil is developed for the toroidal field coil and some coils are developed for critical current measurement. Superconductor is applied to the superconducting bus-line between the superconducting coils and the current leads, and the bus-line is being developed for the Large Helical Device. This report describes an abstract of these equipment. (author)

  15. First electrical tests on a machine with an AC superconducting stator winding

    International Nuclear Information System (INIS)

    Brunet, Y.; Tixador, P.; Laumond, Y.; Sabrie, J.L.

    1988-01-01

    A three phase superconducting stator winding has been built using a low losses NbTi wire under 50 Hz varying magnetic field and current. It has first been necessary to design an horizontal helium cryostat with fiber-glass composites to avoid the permanent eddy-current losses of the rotating magnetic fields. The liquid helium vessel, containing the armature, is dismountable. The cryostat is 900 mm long and the rotor bore has a diameter of 180 mm. The windings are wounded on five concentric fiber glass cylinders with a thin impregnation of an epoxy film adhesive. The first electrical tests have been performed using a normal iron rotor inside the superconducting stator. No load and permanent tests have been achieved up to a power of 13 kVA. The 18,5 kVA predicted have not been reached because of the present inductor, not yet superconducting

  16. Two gap superconductivity in Ba0.55K0.45Fe2As2 single crystals studied by the directional point-contact Andreev reflection spectroscopy

    International Nuclear Information System (INIS)

    Szabo, P.; Pribulova, Z.; Pristas, G.; Bud'ko, S.L.; Canfield, P.C.; Samuely, P.

    2009-01-01

    First directional point-contact Andreev reflection spectroscopy on the Ba 0.55 K 0.45 Fe 2 As 2 single crystals is presented. The spectra show significant differences when measured in the ab plane in comparison with those measured in the c direction. In the latter case no traces of superconducting energy gap could be found, just a reduced point-contact conductance persisting up to about 100 K and indicating reduced density of states. On the other hand within the ab plane two nodeless superconducting energy gaps Δ S ∼2-5 meV and Δ L ∼9-11 meV are detected.

  17. Protection for low current superconducting coils wound with insulated strand cable

    International Nuclear Information System (INIS)

    Satti, J.

    1980-09-01

    The insulated strand cable concept for winding of low current superconducting coil leads to an ideal quench protection by induction coupling. A superconducting secondary loop was made within a cable of a 6.2 Henry dipole coil. When quenching occurred, current was induced in the secondary strand above the critical value. The normal strand quenched the whole cable due to good thermal contact. The secondary loop works as a heater turned on as the wire becomes normal throughout the coil. With a well spread quench, the energy dissipation density is decreased thus preventing local burnout. The mechanism is possible because of close coupling that is present in the insulated cable as in bifilar winding. For the coil tested a 12 strand cable was used, thus a favorable 11 to 1 turn ratio was obtained for the primary to secondary. The superconductor in the secondary had a lower resistance until the critical current was achieved. A theoretical explanation is described for a simplified circuit. Test on the dipole coil with four individual shells showed that the one shell protected with the induced coupling heater always had a more rapid reduction of current. The induced coupling heater tested and explained in this paper works automatically and does not rely on mechanical or electrical devices

  18. Superconducting magnets technologies for large accelerator

    International Nuclear Information System (INIS)

    Ogitsu, Toru

    2017-01-01

    The first hadron collider with superconducting magnet technologies was built at Fermi National Accelerator Laboratory as TEVATRON. Since then, the superconducting magnet technologies are widely used in large accelerator applications. The paper summarizes the superconducting magnet technologies used for large accelerators. (author)

  19. Experimental testing and modelling of a resistive type superconducting fault current limiter using MgB2 wire

    International Nuclear Information System (INIS)

    Smith, A C; Pei, X; Oliver, A; Husband, M; Rindfleisch, M

    2012-01-01

    A prototype resistive superconducting fault current limiter (SFCL) was developed using single-strand round magnesium diboride (MgB 2 ) wire. The MgB 2 wire was wound with an interleaved arrangement to minimize coil inductance and provide adequate inter-turn voltage withstand capability. The temperature profile from 30 to 40 K and frequency profile from 10 to 100 Hz at 25 K were tested and reported. The quench properties of the prototype coil were tested using a high current test circuit. The fault current was limited by the prototype coil within the first quarter-cycle. The prototype coil demonstrated reliable and repeatable current limiting properties and was able to withstand a potential peak current of 372 A for one second without any degradation of performance. A three-strand SFCL coil was investigated and demonstrated scaled-up current capacity. An analytical model to predict the behaviour of the prototype single-strand SFCL coil was developed using an adiabatic boundary condition on the outer surface of the wire. The predicted fault current using the analytical model showed very good correlation with the experimental test results. The analytical model and a finite element thermal model were used to predict the temperature rise of the wire during a fault. (paper)

  20. Filament bundle location influence on coupling losses in superconducting composites

    International Nuclear Information System (INIS)

    Ito, Daisuke; Koizumi, Misao; Hamajima, Takataro; Nakane, Fumoto.

    1983-01-01

    The ac losses in multifilamentary superconducting composites with different superconducting filament bundle positions have been measured using the magnetization method in order to reveal the relation between filament bundle position and coupling losses. Loss components depending on dB/dt in a mixed matrix superconducting composite, whose filament bundle is located in a central region surrounded by an outer stabilizing copper sheath, has been compared with another superconducting composite whose stabilizing copper is located in a central region surrounded by an outer filament bundle. In both conductors, key parameters, such as filament twistpitch, wire diameter and amount of copper stabilizer, were almost the same. Applied magnetic field is 2 Tesla with 0.05-2 Tesla/sec field change rate. Experimental results indicate that coupling losses between filaments in the composite with the filament bundle located in the central region is smaller than the composite with the filament bundle located in the outer region. A similar conclusion was reached theoretically by B. Truck. Coupling loss values obtained by the experiment show good agreement with calculated values with the equations proposed by B. Truck. It is also pointed out that a copper stabilizer, divided by the CuNi barrier into small regions, like a honeycomb, causes anomalous increasing in the copper resistivity due to Ni diffusion during heat treatment. (author)

  1. Mechanical design features of the MSU K-800 cyclotron superconducting coil

    International Nuclear Information System (INIS)

    Lawton, D.; Blosser, H.G.; Moskalik, J.M.; Stork, G.A.

    1984-01-01

    The winding of the K-800 cyclotron superconducting magnet coil was completed in late 1983. The windings consist of four separate coils (symmetrical large and small coils on each side of the median plane). The coils are wound in vertical layers in a spiral fashion. The large coils are 32 layers with 2329 total turns each (59,000 feet of wire) and the small coils are 32 layers with 1544 turns each (39,000 feet of wire). The spiral winding was achieved by supporting the first turn of a layer by a set of gradually increasing spacers with subsequent turns supported by previous turns. Winding was done on the 10 foot diameter table vertical lathe. The winding apparatus was mounted on the lathe's tool arm which had an automatic vertical feed to match the spiral path of the wire. The superconducting cable has a retangular cross section (with rounded corners) of dimentions .207 inches x .150 inches. Approximately 200 niobium titanium filaments are contained in a .04 inch x .06 inches copper insert that is soldered (50/50 lead tin) in a slot in the side of the copper conductor substrate

  2. Note: Progress on the use of MgB2 superconducting joint technique for the development of MgB2 magnets for magnetic resonance imaging (MRI).

    Science.gov (United States)

    Kim, Y G; Song, J B; Kim, J C; Kim, J M; Yoo, B H; Yun, S B; Hwang, D Y; Lee, H G

    2017-08-01

    This note presents a superconducting joint technique for the development of MgB 2 magnetic resonance imaging (MRI) magnets. The MgB 2 superconducting joint was fabricated by a powder processing method using Mg and B powders to establish a wire-bulk-wire connection. The joint resistance measured using a field-decay method was magnets operating in the persistent current mode.

  3. Liquid phase sintered superconducting cermet

    International Nuclear Information System (INIS)

    Ray, S.P.

    1990-01-01

    This patent describes a method of making a superconducting cermet having superconducting properties with improved bulk density, low porosity and in situ stabilization. It comprises: forming a structure of a superconducting ceramic material having the formula RM 2 Cu 3 O (6.5 + x) wherein R is one or more rare earth elements capable of reacting to form a superconducting ceramic, M is one or more alkaline earth metal elements selected from barium and strontium capable of reacting to form a superconducting ceramic, x is greater than 0 and less than 0.5; and a precious metal compound in solid form selected from the class consisting of oxides, sulfides and halides of silver; and liquid phase sintering the mixture at a temperature wherein the precious metal of the precious metal compound is molten and below the melting point of the ceramic material. The liquid phase sintering is carried out for a time less than 36 hours but sufficient to improve the bulk density of the cermet

  4. Japan. Superconductivity for Smart Grids

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.

    2012-11-15

    Currently, many smart grid projects are running or planned worldwide. These aim at controlling the electricity supply more efficiently and more stably in a new power network system. In Japan, especially superconductivity technology development projects are carried out to contribute to the future smart grid. Japanese cable makers such as Sumitomo Electric and Furukawa Electric are leading in the production of high-temperature superconducting (HTS) power cables. The world's largest electric current and highest voltage superconductivity proving tests have been started this year. Big cities such as Tokyo will be expected to introduce the HTS power cables to reduce transport losses and to meet the increased electricity demand in the near future. Superconducting devices, HTS power cables, Superconducting Magnetic Energy Storage (SMES) and flywheels are the focus of new developments in cooperations between companies, universities and research institutes, funded by the Japanese research and development funding organization New Energy and Industrial Technology Development Organization (NEDO)

  5. Low-velocity superconducting accelerating structures

    International Nuclear Information System (INIS)

    Delayen, J.R.

    1990-01-01

    The present paper reviews the status of RF superconductivity as applied to low-velocity accelerating properties. Heavy-ion accelerators must accelerate efficiently particles which travel at a velocity much smaller than that of light particles, whose velocity changes along accelerator, and also different particles which have different velocity profiles. Heavy-ion superconducting accelerators operate at frequencies which are lower than high-energy superconducting accelerators. The present paper first discusses the basic features of heavy-ion superconducting structures and linacs. Design choices are then addressed focusing on structure geometry, materials, frequency, phase control, and focusing. The report also gives an outline of the status of superconducting booster projects currently under way at the Argonne National Laboratory, SUNY Stony Brook, Weizmann Institute, University of Washington, Florida State, Saclay, Kansas State, Daresbury, Japanese Atomic Energy Research Institute, Legnaro, Bombay, Sao Paulo, ANU (Canberra), and Munich. Recent developments and future prospects are also described. (N.K.) 68 refs

  6. Superconducting cyclotrons

    International Nuclear Information System (INIS)

    Blosser, H.G.; Johnson, D.A.; Burleigh, R.J.

    1976-01-01

    Superconducting cyclotrons are particularly appropriate for acceleration of heavy ions. A review is given of design features of a superconducting cyclotron with energy 440 (Q 2 /A) MeV. A strong magnetic field (4.6 tesla average) leads to small physical size (extraction radius 65 cm) and low construction costs. Operating costs are also low. The design is based on established technology (from present cyclotrons and from large bubble chambers). Two laboratories (in Chalk River, Canada and in East Lansing, Michigan) are proceeding with construction of full-scale prototype components for such cyclotrons

  7. Superconducting phase transition in STM tips

    Energy Technology Data Exchange (ETDEWEB)

    Eltschka, Matthias; Jaeck, Berthold; Assig, Maximilian; Etzkorn, Markus; Ast, Christian R. [Max Planck Institute for Solid State Research, Stuttgart (Germany); Kern, Klaus [Max Planck Institute for Solid State Research, Stuttgart (Germany); Ecole Polytechnique Federale de Lausanne (Switzerland)

    2015-07-01

    The superconducting properties of systems with dimensions comparable to the London penetration depth considerably differ from macroscopic systems. We have studied the superconducting phase transition of vanadium STM tips in external magnetic fields. Employing Maki's theory we extract the superconducting parameters such as the gap or the Zeeman splitting from differential conductance spectra. While the Zeeman splitting follows the theoretical description of a system with s=1/2 and g=2, the superconducting gaps as well as the critical fields depend on the specific tip. For a better understanding of the experimental results, we solve a one dimensional Usadel equation modeling the superconducting tip as a cone with the opening angle α in an external magnetic field. We find that only a small region at the apex of the tip is superconducting in high magnetic fields and that the order of the phase transition is directly determined by α. Further, the spectral broadening increases with α indicating an intrinsic broadening mechanism due to the conical shape of the tip. Comparing these calculations to our experimental results reveals the order of the superconducting phase transition of the STM tips.

  8. Design Aspects on Winding of an MgB2 Superconducting Generator Coil

    DEFF Research Database (Denmark)

    Magnusson, N.; Eliassen, J.C.; Abrahamsen, Asger Bech

    2015-01-01

    copper conductors at room temperature at one tenth of the wire cost per unit carried current. In the framework of the European project INNWIND.EU, an MgB2 superconducting generator pole will be designed, built and tested. Some of the design aspects of this work with emphasis on the winding process...... and associated coil insulation are discussed. An overall high current density in the coil is of crucial importance to obtain clear benefits compared to conventional solutions. The wire itself may be the most important parameter in that respect. However, the overall current density of the coil is also influenced......% compared to the use of an additional, dedicated, electrical insulation like Kapton for wet-winding or glass-fibre for dry-winding followed by vacuum impregnation. We show the results of a trial winding of 500 m of MgB2 superconducting wire into a double pancake coil using the wet-winding technique...

  9. Superconducting quantum circuits theory and application

    Science.gov (United States)

    Deng, Xiuhao

    Superconducting quantum circuit models are widely used to understand superconducting devices. This thesis consists of four studies wherein the superconducting quantum circuit is used to illustrate challenges related to quantum information encoding and processing, quantum simulation, quantum signal detection and amplification. The existence of scalar Aharanov-Bohm phase has been a controversial topic for decades. Scalar AB phase, defined as time integral of electric potential, gives rises to an extra phase factor in wavefunction. We proposed a superconducting quantum Faraday cage to detect temporal interference effect as a consequence of scalar AB phase. Using the superconducting quantum circuit model, the physical system is solved and resulting AB effect is predicted. Further discussion in this chapter shows that treating the experimental apparatus quantum mechanically, spatial scalar AB effect, proposed by Aharanov-Bohm, can't be observed. Either a decoherent interference apparatus is used to observe spatial scalar AB effect, or a quantum Faraday cage is used to observe temporal scalar AB effect. The second study involves protecting a quantum system from losing coherence, which is crucial to any practical quantum computation scheme. We present a theory to encode any qubit, especially superconducting qubits, into a universal quantum degeneracy point (UQDP) where low frequency noise is suppressed significantly. Numerical simulations for superconducting charge qubit using experimental parameters show that its coherence time is prolong by two orders of magnitude using our universal degeneracy point approach. With this improvement, a set of universal quantum gates can be performed at high fidelity without losing too much quantum coherence. Starting in 2004, the use of circuit QED has enabled the manipulation of superconducting qubits with photons. We applied quantum optical approach to model coupled resonators and obtained a four-wave mixing toolbox to operate photons

  10. Superconducting tin core fiber

    International Nuclear Information System (INIS)

    Homa, Daniel; Liang, Yongxuan; Hill, Cary; Kaur, Gurbinder; Pickrell, Gary

    2015-01-01

    In this study, we demonstrated superconductivity in a fiber with a tin core and fused silica cladding. The fibers were fabricated via a modified melt-draw technique and maintained core diameters ranging from 50-300 microns and overall diameters of 125-800 microns. Superconductivity of this fiber design was validated via the traditional four-probe test method in a bath of liquid helium at temperatures on the order of 3.8 K. The synthesis route and fiber design are perquisites to ongoing research dedicated all-fiber optoelectronics and the relationships between superconductivity and the material structures, as well as corresponding fabrication techniques. (orig.)

  11. ESCAR superconducting magnet system

    International Nuclear Information System (INIS)

    Gilbert, W.S.; Meuser, R.B.; Pope, W.L.; Green, M.A.

    1975-01-01

    Twenty-four superconducting dipoles, each about 1 meter long, provide the guide field for the Experimental Superconducting Accelerator Ring proton accelerator--storage ring. Injection of 50 MeV protons corresponds to a 3 kG central dipole field, and a peak proton energy of 4.2 GeV corresponds to a 46 kG central field. Thirty-two quadrupoles provide focusing. The 56 superconducting magnets are contained in 40 cryostats that are cryogenically connected in a novel series ''weir'' arrangement. A single 1500 W refrigeration plant is required. Design and testing of the magnet and cryostat system are described. (U.S.)

  12. Superconducting six-axis accelerometer

    Science.gov (United States)

    Paik, H. J.

    1990-01-01

    A new superconducting accelerometer, capable of measuring both linear and angular accelerations, is under development at the University of Maryland. A single superconducting proof mass is magnetically levitated against gravity or any other proof force. Its relative positions and orientations with respect to the platform are monitored by six superconducting inductance bridges sharing a single amplifier, called the Superconducting Quantum Interference Device (SQUID). The six degrees of freedom, the three linear acceleration components and the three angular acceleration components, of the platform are measured simultaneously. In order to improve the linearity and the dynamic range of the instrument, the demodulated outputs of the SQUID are fed back to appropriate levitation coils so that the proof mass remains at the null position for all six inductance bridges. The expected intrinsic noise of the instrument is 4 x 10(exp -12)m s(exp -2) Hz(exp -1/2) for linear acceleration and 3 x 10(exp -11) rad s(exp -2) Hz(exp -1/2) for angular acceleration in 1-g environment. In 0-g, the linear acceleration sensitivity of the superconducting accelerometer could be improved by two orders of magnitude. The design and the operating principle of a laboratory prototype of the new instrument is discussed.

  13. Superconductivity

    International Nuclear Information System (INIS)

    Narlikar, A.V.

    1993-01-01

    Amongst the numerous scientific discoveries that the 20th century has to its credit, superconductivity stands out as an exceptional example of having retained its original dynamism and excitement even for more than 80 years after its discovery. It has proved itself to be a rich field by continually offering frontal challenges in both research and applications. Indeed, one finds that a majority of internationally renowned condensed matter theorists, at some point of their career, have found excitement in working in this important area. Superconductivity presents a unique example of having fetched Nobel awards as many as four times to date, and yet, interestingly enough, the field still remains open for new insights and discoveries which could undeniably be of immense technological value. 1 fig

  14. On anyon superconductivity--

    International Nuclear Information System (INIS)

    Chen, Y.-H.; Wilczek, F.; Witten, E.; Halperin, B.I.

    1989-01-01

    We investigate the statistical mechanics of a gas of fractional statistics particles in 2 + 1 dimensions. In the case of statistics very close to Fermi statistics (statistical parameter θ = π(1 - 1/n), for large n), the effect of the statistics is a weak attraction. Building upon earlier RPA calculation for the case n = 2, the authors argue that for large n perturbation theory is reliable and exhibits superfluidity (or superconductivity after coupling to electromagnetism). They describe the order parameter for this superconductng phase in terms of spontaneous breaking of commutativity of translations as opposed to the usual pairing order parameters. The vortices of the superconducting anyon gas are charged, and superconducting order parameters of the usual type vanish. They investigate the characteristic P and T violating phenomenology

  15. ORNL superconducting technology program for electric power systems

    Science.gov (United States)

    Hawsey, R. A.

    1994-04-01

    The Oak Ridge National Laboratory (ORNL) Superconducting Technology Program is conducted as part of a national effort by the US Department of Energy's Office of Energy Efficiency and Renewable Energy to develop the technology base needed by US industry for commercial development of electric power applications of high-temperature superconductivity. The two major elements of this program are conductor development and applications development. This document describes the major research and development activities for this program together with related accomplishments. The technical progress reported was summarized from information prepared for the FY 1993 Annual Program Review held July 28--29, 1993. This ORNL program is highly leveraged by the staff and other resources of US industry and universities. In fact, nearly three-fourths of the ORNL effort is devoted to industrial competitiveness projects with private companies. Interlaboratory teams are also in place on a number of industry-driven projects. Patent disclosures, working group meetings, staff exchanges, and joint publications and presentations ensure that there is technology transfer to US industry. Working together, the collaborative teams are making rapid progress in solving the scientific and technical issues necessary for the commercialization of long lengths of practical high-temperature superconductor wire and wire products.

  16. GLAG theory for superconducting property variations with A15 composition in Nb3Sn wires.

    Science.gov (United States)

    Li, Yingxu; Gao, Yuanwen

    2017-04-25

    We present a model for the variation of the upper critical field H c2 with Sn content in A15-type Nb-Sn wires, within the Ginzburg-Landau-Abrikosov-Gor'kov (GLAG) theory frame. H c2 at the vicinity of the critical temperature T c is related quantitatively to the electrical resistivity ρ, specific heat capacity coefficient γ and T c . H c2 versus tin content is theoretically formulated within the GLAG theory, and generally reproduces the experiment results. As Sn content gradually approaches the stoichiometry, A15-type Nb-Sn undergoes a transition from the dirty limit to clean limit, split by the phase transformation boundary. The H-T phase boundary and pinning force show different behaviors in the cubic and tetragonal phase. We dipict the dependence of the composition gradient on the superconducting properties variation in the A15 layer, as well as the curved tail at vicinity of H c2 in the Kramer plot of the Nb 3 Sn wire. This helps understanding of the inhomogeneous-composition inducing discrepancy between the results by the state-of-art scaling laws and experiments.

  17. Radiation effects on superconductivity

    International Nuclear Information System (INIS)

    Brown, B.S.

    1975-01-01

    The effect of radiation on the superconducting transition temperature (T/sub c/), upper critical field (H/sub c2/), and volume-pinning-force density (F/sub p/) were discussed for the three kinds of superconducting material (elements, alloys, and compounds). 11 figures, 3 tables, 86 references

  18. Superconductivity in borides and carbides

    International Nuclear Information System (INIS)

    Muranaka, Takahiro

    2007-01-01

    It was thought that intermetallic superconductors do not exhibit superconductivity at temperatures over 30 K because of the Bardeen-Cooper-Schrieffer (BCS) limit; therefore, researchers have been interested in high-T c cuprates. Our group discovered high-T c superconductivity in MgB 2 at 39 K in 2001. This discovery has initiated a substantial interest in the potential of high-T c superconductivity in intermetallic compounds that include 'light' elements (borides, carbides, etc.). (author)

  19. Study of superconducting Nb3Sn coils

    International Nuclear Information System (INIS)

    Vivet, B.

    1963-01-01

    Composite superconducting Nb 3 Sn wires with a diameter of 0.5 mm and a length of about 100 m were made, and Hc-Ic diagrams were plotted up to fields of 80 kgauss for short lengths. Two solenoids producing fields of about 20 kgauss were studied. Nb 3 Sn solenoids, as opposed to those of Nb-Zr or Nb-Ti, appear to have a predictable behavior. Solenoids with less insulation produced stronger fields than heavily insulated solenoids. (author) [fr

  20. Superconductivity and magnet technology

    International Nuclear Information System (INIS)

    Lubell, M.S.

    1975-01-01

    The background theory of superconducting behavior is reviewed. Three parameters that characterize superconducting materials with values of commercial materials as examples are discussed. More than 1000 compounds and alloy systems and 26 elements are known to exhibit superconducting properties under normal conditions at very low temperatures. A wide variety of crystal structures are represented among the known superconductors. The most important ones do seem to have cubic symmetry such as the body-centered cubic (NbZr and NbTi), face-centered cubic (NbN), and the A15 or β-tungsten structures (Nb 3 Sn), V 3 Ga, Nb 3 Ge, Nb 3 Al, and V 3 Si). Attempts to understand some of the particular phenomena associated with superconductors as a necessary prelude to constructing superconducting magnets are discussed by the author. The origin of degradation is briefly discussed and methods to stabilize magnets are illustrated. The results of Oak Ridge National Laboratory design studies of toroidal magnet systems for fusion reactors are described

  1. Hybrid superconducting magnetic suspensions

    International Nuclear Information System (INIS)

    Tixador, P.; Hiebel, P.; Brunet, Y.; Chaud, X.; Gautier-Picard, P.

    1996-01-01

    Superconductors, especially high T c ones, are the most attractive materials to design stable and fully passive magnetic suspensions which have to control five degrees of freedom. The hybrid superconducting magnetic suspensions present high performances and a simple cooling mode. They consist of a permanent magnet bearing, stabilized by a suitable magnet-superconductor structure. Several designs are given and compared in terms of forces and stiffnesses. The design of the magnet bearing plays an important part. The superconducting magnetic bearing participates less in levitation but must provide a high stabilizing stiffness. This is achieved by the magnet configuration, a good material in term of critical current density and field cooling. A hybrid superconducting suspension for a flywheel is presented. This system consists of a magnet thrust bearing stabilized by superconductors interacting with an alternating polarity magnet structure. First tests and results are reported. Superconducting materials are magnetically melt-textured YBaCuO

  2. Enhanced superconductivity at the interface of W/Sr2RuO4 point contact

    Science.gov (United States)

    Wei, Jian; Wang, He; Lou, Weijian; Luo, Jiawei; Liu, Ying; Ortmann, J. E.; Mao, Z. Q.

    Differential resistance measurements are conducted for point contacts (PCs) between the Sr2RuO4 (SRO) single crystal and the tungsten tip. Since the tungsten tip is hard enough to penetrate through the surface layer, consistent superconducting features are observed. Firstly, with the tip pushed towards the crystal, the zero bias conductance peak (ZBCP) due to Andreev reflection at the normal-superconducting interface increases from 3% to more than 20%, much larger than previously reported, and extends to temperature higher than the bulk transition temperature. Reproducible ZBCP within 0.2 mV may also help determine the gap value of SRO, on which no consensus has been reached. Secondly, the logarithmic background can be fitted with the Altshuler-Aronov theory of electron-electron interaction for tunneling into quasi two dimensional electron system. Feasibility of such fitting confirms that spectroscopic information like density of states is probed, and electronic temperature retrieved from such fitting can be important to analyse the PC spectra. Third, at bias much higher than 0.2 mV there are conductance dips due to the critical current effect and these dips persist up to 6.2 K. For more details see. National Basic Research Program of China (973 Program) through Grant No. 2011CBA00106 and No. 2012CB927400.

  3. Recent advances in fullerene superconductivity

    CERN Document Server

    Margadonna, S

    2002-01-01

    Superconducting transition temperatures in bulk chemically intercalated fulleride salts reach 33 K at ambient pressure and in hole-doped C sub 6 sub 0 derivatives in field-effect-transistor (FET) configurations, they reach 117 K. These advances pose important challenges for our understanding of high-temperature superconductivity in these highly correlated organic metals. Here we review the structures and properties of intercalated fullerides, paying particular attention to the correlation between superconductivity and interfullerene separation, orientational order/disorder, valence state, orbital degeneracy, low-symmetry distortions, and metal-C sub 6 sub 0 interactions. The metal-insulator transition at large interfullerene separations is discussed in detail. An overview is also given of the exploding field of gate-induced superconductivity of fullerenes in FET electronic devices.

  4. Superconductivity in Layered Organic Metals

    Directory of Open Access Journals (Sweden)

    Jochen Wosnitza

    2012-04-01

    Full Text Available In this short review, I will give an overview on the current understanding of the superconductivity in quasi-two-dimensional organic metals. Thereby, I will focus on charge-transfer salts based on bis(ethylenedithiotetrathiafulvalene (BEDT-TTF or ET for short. In these materials, strong electronic correlations are clearly evident, resulting in unique phase diagrams. The layered crystallographic structure leads to highly anisotropic electronic as well as superconducting properties. The corresponding very high orbital critical field for in-plane magnetic-field alignment allows for the occurrence of the Fulde–Ferrell– Larkin–Ovchinnikov state as evidenced by thermodynamic measurements. The experimental picture on the nature of the superconducting state is still controversial with evidence both for unconventional as well as for BCS-like superconductivity.

  5. Interplay of magnetism and superconductivity

    International Nuclear Information System (INIS)

    Akhavan, M.

    2006-01-01

    After about two decades of intense research since the discovery of high-temperature superconductivity (HTSC) in cuprates, although many aspects of the physics and chemistry of these cuprate superconductors are now well understood, the underlying pairing mechanism remains elusive. Magnetism and superconductivity are usually thought as incompatible, but in number of special materials including HTSCs these two mutually excluding mechanisms are found to coexist. The presence in a system of superconductivity and magnetism, gives rise to a large number of interesting phenomenon. This article provides perspective on recent developments and their implications for our understanding of the interplay between magnetism and superconductivity in new materials. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  6. Proceedings of the fourth international conference and exhibition: World Congress on superconductivity. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Krishen, K.; Burnham, C. [eds.] [National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center

    1994-12-31

    This document contains papers presented at the 4th International Conference Exhibition: World Congress on Superconductivity held at the Marriott Orlando World Center, Orlando, Florida, June 27--July 1, 1994. This conference encompassed research, technology, applications, funding, political, and social aspects of superconductivity. Specifically, the areas of research, technology, and development covered during the conference included high-temperature materials, thin films, C-60 based superconductors, persistent magnetic fields and shielding, fabrication methodology, space applications, physical applications, performance characterization, device applications, weak link effects and flux motion, accelerator technology, superconductivity energy, storage, future research and development directions, medical applications, granular superconductors, wire fabrication technology, computer applications, technical and commercial challenges, and power and energy applications. The key objective of this conference was to provide a forum for the world community to share technological results of recent advances made in the field of superconductivity and to discuss translation of the research to technology which will benefit humanity. More than 150 presentations were made at this conference. Individual papers are indexed separately on the Energy Data Bases.

  7. Proceedings of the fourth international conference and exhibition: World Congress on superconductivity. Volume 2

    International Nuclear Information System (INIS)

    Krishen, K.; Burnham, C.

    1994-01-01

    This document contains papers presented at the 4th International Conference Exhibition: World Congress on Superconductivity held at the Marriott Orlando World Center, Orlando, Florida, June 27--July 1, 1994. This conference encompassed research, technology, applications, funding, political, and social aspects of superconductivity. Specifically, the areas of research, technology, and development covered during the conference included high-temperature materials, thin films, C-60 based superconductors, persistent magnetic fields and shielding, fabrication methodology, space applications, physical applications, performance characterization, device applications, weak link effects and flux motion, accelerator technology, superconductivity energy, storage, future research and development directions, medical applications, granular superconductors, wire fabrication technology, computer applications, technical and commercial challenges, and power and energy applications. The key objective of this conference was to provide a forum for the world community to share technological results of recent advances made in the field of superconductivity and to discuss translation of the research to technology which will benefit humanity. More than 150 presentations were made at this conference. Individual papers are indexed separately on the Energy Data Bases

  8. The US market for high-temperature superconducting wire in transmission cable applications

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, D

    1996-04-01

    Telephone interviews were conducted with 23 utility engineers concerning the future prospects for high-temperature superconducting (HTS) transmission cables. All have direct responsibility for transmission in their utility, most of them in a management capacity. The engineers represented their utilities as members of the Electric Power Research Institute`s Underground Transmission Task Force (which has since been disbanded). In that capacity, they followed the superconducting transmission cable program and are aware of the cryogenic implications. Nineteen of the 23 engineers stated the market for underground transmission would grow during the next decade. Twelve of those specified an annual growth rate; the average of these responses was 5.6%. Adjusting that figure downward to incorporate the remaining responses, this study assumes an average growth rate of 3.4%. Factors driving the growth rate include the difficulty in securing rights-of-way for overhead lines, new construction techniques that reduce the costs of underground transmission, deregulation, and the possibility that public utility commissions will allow utilities to include overhead costs in their rate base. Utilities have few plans to replace existing cable as preventive maintenance, even though much of the existing cable has exceeded its 40-year lifetime. Ten of the respondents said the availability of a superconducting cable with the same life-cycle costs as a conventional cable and twice the ampacity would induce them to consider retrofits. The respondents said a cable with those characteristics would capture 73% of their cable retrofits.

  9. Superconducting Undulator with Variably Polarized Light

    CERN Document Server

    Hwang, Ching Shiang; Ching Fan, Tai; Li, W P; Lin, P H

    2004-01-01

    This study investigates planar in-vacuo superconducting undulators with periodic length of 5 cm (IVSU5) producing linearly and circularly polarized infrared rays or xrays source. The vertically wound racetrack coil is selected for the coil and pole fabrication of the IVSU5. When the up and down magnetic pole arrays with alternative directions rotated wires in the horizontal plane, a helical field radiates circularly polarized light in the electron storage ring, the free electron laser (FEL), and the energy recovery linac (ERL) facilities. Meanwhile, an un-rotated wire is constructed together with the rotated wire on the same undulator is used to switch the linear horizontal and vertical, the right- and left-circular polarization radiation. Given a periodic length of 5 cm and a gap of 23 mm, the maximum magnetic flux density in the helical undulator are Bz = 1.5 T and Bx = 0.5 T when the wires rotated by 20°. This article describes the main factors of the planar and helical undulator design for FEL and...

  10. Gauge Model of High-Tc Superconductivity

    International Nuclear Information System (INIS)

    Ng, Sze Kui

    2012-01-01

    A simple gauge model of superconductivity is presented. The seagull vertex term of this gauge model gives an attractive potential between electrons for the forming of Cooper pairs of superconductivity. This gauge model gives a unified description of superconductivity and magnetism including antiferromagnetism, pseudogap phenomenon, stripes phenomenon, paramagnetic Meissner effect, Type I and Type II supeconductivity and high-T c superconductivity. The doping mechanism of superconductivity is found. It is shown that the critical temperature T c is related to the ionization energies of elements and can be computed by a formula of T c . For the high-T c superconductors such as La 2-x Sr x CuO 4 , Y Ba 2 Cu 3 O 7 , and MgB 2 , the computational results of T c agree with the experimental results.

  11. Superconducting active impedance converter

    International Nuclear Information System (INIS)

    Ginley, D.S.; Hietala, V.M.; Martens, J.S.

    1993-01-01

    A transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductors allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10-80 K. temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology. 12 figures

  12. Magnetization Modeling of Twisted Superconducting Filaments

    CERN Document Server

    Satiramatekul, T; Devred, Arnaud; Leroy, Daniel

    2007-01-01

    This paper presents a new Finite Element numerical method to analyze the coupling between twisted filaments in a superconducting multifilament composite wire. To avoid the large number of elements required by a 3D code, the proposed method makes use of the energy balance principle in a 2D code. The relationship between superconductor critical current density and local magnetic flux density is implemented in the program for the Bean and modified Kim models. The modeled wire is made up of six filaments twisted together and embedded in a lowresistivity matrix. Computations of magnetization cycle and of the electric field pattern have been performed for various twist pitch values in the case of a pure copper matrix. The results confirm that the maximum magnetization depends on the matrix conductivity, the superconductor critical current density, the applied field frequency, and the filament twist pitch. The simulations also lead to a practical criterion for wire design that can be used to assess whether or not th...

  13. Superconducting linac booster

    International Nuclear Information System (INIS)

    Srinivasan, B.; Betigeri, M.G.; Pandey, M.K.; Pillay, R.G.; Kurup, M.B.

    1997-01-01

    The report on superconducting LINAC booster, which is a joint project of Bhabha Atomic Research Centre (BARC) and Tata Institute of Fundamental Research (TIFR), brings out the work accomplished so far towards the development of the technology of superconducting LINAC to boost the energy of ions from the 14UD Pelletron. The LINAC is modular in construction with each module comprising of a helium cryostat housing four lead-plated quarter wave resonators. The resonators are superconducting for temperatures below 7.19K. An energy boost of 2 MeV/q per module is expected to be achieved. The first module and the post-tandem superbuncher have been fabricated and tested on the LINAC beam line. This report gives a summary of the technological achievements and also brings out the difficulties encountered during the R and D phase. (author)

  14. Superconducting super collider

    International Nuclear Information System (INIS)

    Limon, P.J.

    1987-01-01

    The Superconducting Super Collider is to be a 20 TeV per beam proton-proton accelerator and collider. Physically the SCC will be 52 miles in circumference and slightly oval in shape. The use of superconducting magnets instead of conventional cuts the circumference from 180 miles to the 52 miles. The operating cost of the SCC per year is estimated to be about $200-250 million. A detailed cost estimate of the project is roughly $3 billion in 1986 dollars. For the big collider ring, the technical cost are dominated by the magnet system. That is why one must focus on the cost and design of the magnets. Presently, the process of site selection is underway. The major R and D efforts concern superconducting dipoles. The magnets use niobium-titanium as a conductor stabilized in a copper matrix. 10 figures

  15. Superconductivity in doped two-leg ladder cuprates

    International Nuclear Information System (INIS)

    Qin Jihong; Yuan Feng; Feng Shiping

    2006-01-01

    Within the t-J ladder model, superconductivity with a modified d-wave symmetry in doped two-leg ladder cuprates is investigated based on the kinetic energy driven superconducting mechanism. It is shown that the spin-liquid ground-state at the half-filling evolves into the superconducting ground-state upon doping. In analogy to the doping dependence of the superconducting transition temperature in the planar cuprate superconductors, the superconducting transition temperature in doped two-leg ladder cuprates increases with increasing doping in the underdoped regime, and reaches a maximum in the optimal doping, then decreases in the overdoped regime

  16. International round robin test for mechanical properties of Nb3Sn superconductive wires at room temperature

    International Nuclear Information System (INIS)

    Osamura, K; Nyilas, A; Thoener, M; Seeber, B; Fluekiger, R; Ilyin, Y; Njihuis, A; Ekin, J; Clickner, C; Walsh, R P; Toplosky, V; Shin, H; Katagiri, K; Ochiai, S; Hojo, M; Kubo, Y; Miyashita, K

    2008-01-01

    An international RRT has been carried out in order to establish the test method for mechanical properties of commercial Nb 3 Sn superconductive wires under the cooperation of eleven worldwide research groups. From the stress-strain curve, the following quantities were evaluated; modulus of elasticity, transition of elastic to plastic deformation, proof strength, tensile strength and elongation to fracture. The scatter of measured values was analyzed to evaluate the COV, which is the standard deviation divided by the average. The results made clear how the experimental conditions influence the determination of physical quantities. The most important point is that large COVs for modulus of elasticity and proof strength from the initial slope are caused by the narrow elastic limit. Methods have been discussed to improve the statistics of experimental results obtained from the international RRT

  17. The Influence of CuFe2O4 Nanoparticles on Superconductivity of MgB2

    Science.gov (United States)

    Novosel, Nikolina; Pajić, Damir; Skoko, Željko; Mustapić, Mislav; Babić, Emil; Zadro, Krešo; Horvat, Joseph

    The influence of CuFe2O4 nanoparticle doping on superconducting properties of Fe-sheated MgB2 wires has been studied. The wires containing 0, 3 and 7.5 wt.% of monodisperse superparamagnetic nanoparticles (˜7 nm) were sintered at 650°C or 750°C for 1 hour in the pure argon atmosphere. X-ray diffraction patterns of doped samples showed very small maxima corresponding to iron boride and an increase in the fraction of MgO phase indicating some interaction of nanoparticles with Mg and B. Both magnetic and transport measurements (performed in the temperature range 2-42 K and magnetic field up to 16 T) showed strong deterioration of the superconducting properties upon doping with CuFe2O4. The transition temperatures, Tc, of doped samples decreased for about 1.4 K per wt.% of CuFe2O4. Also, the irreversibility fields Birr(T) decreased progressively with increasing doping. Accordingly, also the suppression of Jc with magnetic field became stronger. The observed strong deterioration of superconducting properties of MgB2 wires is at variance with reported enhancement of critical currents at higher temperatures (determined from magnetization) in bulk MgB2 samples doped with Fe3O4 nanoparticles. The probable reason for this discrepancy is briefly discussed

  18. Superconducting pipes and levitating magnets.

    Science.gov (United States)

    Levin, Yan; Rizzato, Felipe B

    2006-12-01

    Motivated by a beautiful demonstration of the Faraday and the Lenz laws in which a small neodymium magnet falls slowly through a conducting nonferromagnetic tube, we consider the dynamics of a magnet falling coaxially through a superconducting pipe. Unlike the case of normal conducting pipes, in which the magnet quickly reaches the terminal velocity, inside a superconducting tube the magnet falls freely. On the other hand, to enter the pipe the magnet must overcome a large electromagnetic energy barrier. For sufficiently strong magnets, the barrier is so large that the magnet will not be able to penetrate it and will be levitated over the mouth of the pipe. We calculate the work that must done to force the magnet to enter a superconducting tube. The calculations show that superconducting pipes are very efficient at screening magnetic fields. For example, the magnetic field of a dipole at the center of a short pipe of radius a and length L approximately > a decays, in the axial direction, with a characteristic length xi approximately 0.26a. The efficient screening of the magnetic field might be useful for shielding highly sensitive superconducting quantum interference devices. Finally, the motion of the magnet through a superconducting pipe is compared and contrasted to the flow of ions through a trans-membrane channel.

  19. Controllable Quantum States Mesoscopic Superconductivity and Spintronics (MS+S2006)

    Science.gov (United States)

    Takayanagi, Hideaki; Nitta, Junsaku; Nakano, Hayato

    2008-10-01

    Josephson effect in diffusive d-wave junctions / T. Yokoyama. Quantum dissipation due to the zero energy bound states in high-T[symbol] superconductor junctions / Shiro Kawabata. Spin-polarized heat transport in ferromagnet/unconventional superconductor junctions / T. Yokoyama. Little-Parks oscillations in chiral p-wave superconducting rings / Mitsuaki Takigawa. Theoretical study of synergy effect between proximity effect and Andreev interface resonant states in triplet p-wave superconductors / Yasunari Tanuma. Theory of proximity effect in unconventional superconductor junctions / Y. Tanaka -- Quantum information. Analyzing the effectiveness of the quantum repeater / Kenichiro Furuta. Architecture-dependent execution time of Shor's algorithm / Rodney Van Meter -- Quantum dots and Kondo effects. Coulomb blockade properties of 4-gated quantum dot / Shinichi Amaha. Order-N electronic structure calculation of n-type GaAs quantum dots / Shintaro Nomura. Transport through double-dots coupled to normal and superconducting leads / Yoichi Tanaka. A study of the quantum dot in application to terahertz single photon counting / Vladimir Antonov. Electron transport through laterally coupled double quantum dots / T. Kubo. Dephasing in Kondo systems: comparison between theory and experiment / F. Mallet. Kondo effect in quantum dots coupled with noncollinear ferromagnetic leads / Daisuke Matsubayashi. Non-crossing approximation study of multi-orbital Kondo effect in quantum dot systems / Tomoko Kita. Theoretical study of electronic states and spin operation in coupled quantum dots / Mikio Eto. Spin correlation in a double quantum dot-quantum wire coupled system / S. Sasaki. Kondo-assisted transport through a multiorbital quantum dot / Rui Sakano. Spin decay in a quantum dot coupled to a quantum point contact / Massoud Borhani -- Quantum wires, low-dimensional electrons. Control of the electron density and electric field with front and back gates / Masumi Yamaguchi. Effect of the array

  20. Superconducting Metallic Glass Transition-Edge-Sensors

    Science.gov (United States)

    Hays, Charles C. (Inventor)

    2013-01-01

    A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

  1. Cooldown of superconducting magnet strings

    International Nuclear Information System (INIS)

    Yuecel, A.; Carcagno, R.H.

    1995-01-01

    A numerical model for the cooldown of the superconducting magnet strings in the Accelerator System String Test (ASST) Facility at the Superconducting Super Collider (SSC) Laboratory is presented. Numerical results are compared with experimental data from the ASST test runs. Agreement between the numerical predictions and experiments is very good over the entire range from room temperature to liquid helium temperatures. The model can be readily adapted to predict the cooldown and warmup behavior of other superconducting magnets or cold masses

  2. Superconductivity in bad metals

    International Nuclear Information System (INIS)

    Emery, V.J.; Kivelson, S.A.

    1995-01-01

    It is argued that many synthetic metals, including high temperature superconductors are ''bad metals'' with such a poor conductivity that the usual mean-field theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. Some consequences for high temperature superconductors are described

  3. Adaptation of superconducting fault current limiter to high-speed reclosing

    International Nuclear Information System (INIS)

    Koyama, T.; Yanabu, S.

    2009-01-01

    Using a high temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor might break in some cases because of its excessive generation of heat. Therefore, it is desirable to interrupt early the current that flows to superconductor. So, we proposed the SFCL using an electromagnetic repulsion switch which is composed of a superconductor, a vacuum interrupter and a by-pass coil, and its structure is simple. Duration that the current flow in the superconductor can be easily minimized to the level of less than 0.5 cycle using this equipment. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. There is duty of high-speed reclosing after interrupting fault current in the electric power system. After the fault current is interrupted, the back-up breaker is re-closed within 350 ms. So, the electromagnetic repulsion switch should return to former state and the superconductor should be recovered to superconducting state before high-speed reclosing. Then, we proposed the SFCL using an electromagnetic repulsion switch which employs our new reclosing function. We also studied recovery time of the superconductor, because superconductor should be recovered to superconducting state within 350 ms. In this paper, the recovery time characteristics of the superconducting wire were investigated. Also, we combined the superconductor with the electromagnetic repulsion switch, and we did performance test. As a result, a high-speed reclosing within 350 ms was proven to be possible.

  4. Mechanical Design of Superconducting Accelerator Magnets

    International Nuclear Information System (INIS)

    Toral, F

    2014-01-01

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques

  5. Mechanical Design of Superconducting Accelerator Magnets

    CERN Document Server

    Toral, Fernando

    2014-07-17

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

  6. Mechanical Design of Superconducting Accelerator Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Toral, F [Madrid, CIEMAT (Spain)

    2014-07-01

    This paper is about the mechanical design of superconducting accelerator magnets. First, we give a brief review of the basic concepts and terms. In the following sections, we describe the particularities of the mechanical design of different types of superconducting accelerator magnets: solenoids, costheta, superferric, and toroids. Special attention is given to the pre-stress principle, which aims to avoid the appearance of tensile stresses in the superconducting coils. A case study on a compact superconducting cyclotron summarizes the main steps and the guidelines that should be followed for a proper mechanical design. Finally, we present some remarks on the measurement techniques.

  7. Can magnetism and superconductivity coexist

    International Nuclear Information System (INIS)

    Ishikawa, M.

    1982-01-01

    Recent syntheses of rare earth (RE) ternary superconductors such as (RE)Mo 6 X 8 (X=S or Se) and (RE)Rh 4 B 4 have provided the first opportunity to explore the interaction between magnetism and superconductivity in detail owing to their particular crystal structure. The regular sublattice of the rare-earth ions in these new ternary compounds undergoes a ferro- or antiferromagnetic phase transition in the superconducting state. If the transition is antiferromagnetic, the superconductivity is preserved so that true coexistence results. If it is ferromagnetic, on the other hand, the superconductivity eventually gives way to uniform ferromagnetism at low temperatures. However, recent theories predict several possible states of coexistence even in ferromagnetic superconductors. This article reviews aspects of these new phase transitions in ternary superconductors. (author)

  8. New world of Gossamer superconductivity

    International Nuclear Information System (INIS)

    Maki, Kazumi; Haas, Stephan; Parker, David; Won, Hyekyung; Dora, Balazs; Virosztek, Attila

    2006-01-01

    Since the discovery of the high-T c cuprate superconductor La 2-x BaCuO 4 in 1986 by Bednorz and Mueller, controversy regarding the nature or origin of this remarkable superconductivity has continued. However, d-wave superconductivity in the hole-doped cuprates, arising due to the anti-paramagnon exchange, was established around 1994. More recently we have shown that the mean field theory, like the BCS theory of superconductivity and Landau's Fermi liquid theory are adequate to describe the cuprates. The keys for this development are the facts that a) the pseudogap phase is d-wave density wave (dDW) and that the high-T c cuprate superconductivity is gossamer (i.e. it exists in the presence of dDW). (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Superconducting generator technology--an overview

    International Nuclear Information System (INIS)

    Edmonda, J.S.

    1979-01-01

    Application of superconducting technology to field windings of large ac generators provides virtually unlimited field capability without incurring resistive losses in the winding. Several small-scale superconducting generators have been built and tested demonstrating the feasibility of such concepts. For machines of much larger capacity, conceptual designs for 300 Mva and 1200 Mva have been completed. The development of a 300 Mva generator is projected. Designed, engineered and fabricated as a turbo generator, the superconducting machine is to be installed in a power plant, tested and operated in concert with a prime mover, the steam generator and the auxiliary support systems of the power plant. This will provide answers to the viability of operating a superconducting machine and its cryogenic handling systems in a full time, demanding environment. 21 refs

  10. A Cryogenic Magnetostrictive Actuator using a Persistent High Temperature Superconducting Magnet, Part 1: Concept and Design. Part 1; Concept and Design

    Science.gov (United States)

    Horner, Garnett C.; Bromberg, Leslie; Teter, J. P.

    2001-01-01

    Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications, such as Next Generation Space Telescope (NGST), the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Very fast charging and discharging of HTS tubes, as short as 100 microseconds, has been demonstrated. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSSCO 2212 with a

  11. Heavy-ion superconducting linacs

    International Nuclear Information System (INIS)

    Delayen, J.R.

    1989-01-01

    This paper reviews the status of the superconducting heavy-ion accelerators. Most of them are linacs used as boosters for tandem electrostatic accelerators, although the technology is being extended to very low velocity to eliminate the need for an injector. The characteristics and features of the various superconducting heavy-ion accelerators are discussed. 45 refs

  12. Heavy-ion superconducting linacs

    Energy Technology Data Exchange (ETDEWEB)

    Delayen, J.R.

    1989-01-01

    This paper reviews the status of the superconducting heavy-ion accelerators. Most of them are linacs used as boosters for tandem electrostatic accelerators, although the technology is being extended to very low velocity to eliminate the need for an injector. The characteristics and features of the various superconducting heavy-ion accelerators are discussed. 45 refs.

  13. Modal bifurcation in a high-T{sub c} superconducting levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, D; Fujiwara, S; Sugiura, T, E-mail: sugiura@mech.keio.ac.jp [Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, kohoku-ku, Yokohama 223-8522 (Japan)

    2011-05-15

    This paper deals with modal bifurcation of a multi-degree-of-freedom high-T{sub c} superconducting levitation system. As modeling of large-scale high-T{sub c} superconducting levitation applications, where plural superconducting bulks are often used, it can be helpful to consider a system constituting of multiple oscillators magnetically coupled with each other. This paper investigates nonlinear dynamics of two permanent magnets levitated above high-T{sub c} superconducting bulks and placed between two fixed permanent magnets without contact. First, the nonlinear equations of motion of the levitated magnets were derived. Then the method of averaging was applied to them. It can be found from the obtained solutions that this nonlinear two degree-of-freedom system can have two asymmetric modes, in addition to a symmetric mode and an antisymmetric mode both of which also exist in the linearized system. One of the backbone curves in the frequency response shows a modal bifurcation where the two stable asymmetric modes mentioned above appear with destabilization of the antisymmetric mode, thus leading to modal localization. These analytical predictions have been confirmed in our numerical analysis and experiments of free vibration and forced vibration. These results, never predicted by linear analysis, can be important for application of high-T{sub c} superconducting levitation systems.

  14. RADIOFREQUENCY SUPERCONDUCTIVITY: Workshop

    International Nuclear Information System (INIS)

    Lengeler, Herbert

    1989-01-01

    Superconducting radiofrequency is already playing an important role in the beam acceleration system for the TRISTAN electron-positron collider at the Japanese KEK Laboratory and new such systems are being prepared for other major machines. Thus the fourth Workshop on Radiofrequency Superconductivity, organized by KEK under the chairmanship of local specialist Yuzo Kojima and held just before the International Conference on High Energy Accelerators, had much progress to review and even more to look forward to

  15. Connectivity and superconductivity

    CERN Document Server

    Rubinstein, Jacob

    2000-01-01

    The motto of connectivity and superconductivity is that the solutions of the Ginzburg--Landau equations are qualitatively influenced by the topology of the boundaries, as in multiply-connected samples. Special attention is paid to the "zero set", the set of the positions (also known as "quantum vortices") where the order parameter vanishes. The effects considered here usually become important in the regime where the coherence length is of the order of the dimensions of the sample. It takes the intuition of physicists and the awareness of mathematicians to find these new effects. In connectivity and superconductivity, theoretical and experimental physicists are brought together with pure and applied mathematicians to review these surprising results. This volume is intended to serve as a reference book for graduate students and researchers in physics or mathematics interested in superconductivity, or in the Schrödinger equation as a limiting case of the Ginzburg--Landau equations.

  16. Large Superconducting Magnet Systems

    CERN Document Server

    Védrine, P.

    2014-07-17

    The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb$_{3}$Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

  17. Superconducting accelerator magnet design

    International Nuclear Information System (INIS)

    Wolff, S.

    1994-01-01

    Superconducting dipoles, quadrupoles and correction magnets are necessary to achieve the high magnetic fields required for big accelerators presently in construction or in the design phase. Different designs of superconducting accelerator magnets are described and the designs chosen at the big accelerator laboratories are presented. The most frequently used cosθ coil configuration is discussed in detail. Approaches for calculating the magnetic field quality including coil end fields are presented. Design details of the cables, coils, mechanical structures, yokes, helium vessels and cryostats including thermal radiation shields and support structures used in superconducting magnets are given. Necessary material properties are mentioned. Finally, the main results of magnetic field measurements and quench statistics are presented. (orig.)

  18. Large Superconducting Magnet Systems

    Energy Technology Data Exchange (ETDEWEB)

    Védrine, P [Saclay (France)

    2014-07-01

    The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

  19. Zero-bias peaks in the tunneling conductance of spin-orbit-coupled superconducting wires with and without Majorana end-states.

    Science.gov (United States)

    Liu, Jie; Potter, Andrew C; Law, K T; Lee, Patrick A

    2012-12-28

    One of the simplest proposed experimental probes of a Majorana bound state is a quantized (2e(2)/h) value of zero-bias tunneling conductance. When temperature is somewhat larger than the intrinsic width of the Majorana peak, conductance is no longer quantized, but a zero-bias peak can remain. Such a nonquantized zero-bias peak has been recently reported for semiconducting nanowires with proximity induced superconductivity. In this Letter we analyze the relation of the zero-bias peak to the presence of Majorana end states, by simulating the tunneling conductance for multiband wires with realistic amounts of disorder. We show that this system generically exhibits a (nonquantized) zero-bias peak even when the wire is topologically trivial and does not possess Majorana end states. We make comparisons to recent experiments, and discuss the necessary requirements for confirming the existence of a Majorana state.

  20. Acoustic wave spread in superconducting-normal-superconducting sandwich

    International Nuclear Information System (INIS)

    Urushadze, G.I.

    2004-01-01

    The acoustic wave spread, perpendicular to the boundaries between superconducting and normal metals in superconducting-normal-superconducting (SNS) sandwich has been considered. The alternate current flow sound induced by the Green function method has been found and the coefficient of the acoustic wave transmission through the junction γ=(S 1 -S 2 )/S 1 , (where S 1 and S 2 are average energy flows formed on the first and second boundaries) as a function of the phase difference between superconductors has been investigated. It is shown that while the SNS sandwich is almost transparent for acoustic waves (γ 0 /τ), n=0,1,2, ... (where τ 0 /τ is the ratio of the broadening of the quasiparticle energy levels in impurity normal metal as a result of scattering of the carriers by impurities 1/τ to the spacing between energy levels 1/τ 0 ), γ=2, (S 2 =-S 1 ), which corresponds to the full reflection of the acoustic wave from SNS sandwich. This result is valid for the limit of a pure normal metal but in the main impurity case there are two amplification and reflection regions for acoustic waves. The result obtained shows promise for the SNS sandwich as an ideal mirror for acoustic wave reflection

  1. Valence skipping driven superconductivity and charge Kondo effect

    International Nuclear Information System (INIS)

    Yanagisawa, Takashi; Hase, Izumi

    2013-01-01

    Highlights: •Valence skipping in metallic compounds can give rise to an unconventional superconductivity. •Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. •The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. •We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. •There is a high temperature region near the boundary. -- Abstract: Valence skipping in metallic compounds can give rise to an unconventional superconductivity. Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. The superconducting state is changed into a metallic state with a local singlet as the attractive interaction |U| increases. There is a high temperature region near the boundary

  2. Half-metallic superconducting triplet spin multivalves

    Science.gov (United States)

    Alidoust, Mohammad; Halterman, Klaus

    2018-02-01

    We study spin switching effects in finite-size superconducting multivalve structures. We examine F1F2SF3 and F1F2SF3F4 hybrids where a singlet superconductor (S) layer is sandwiched among ferromagnet (F) layers with differing thicknesses and magnetization orientations. Our results reveal a considerable number of experimentally viable spin-valve configurations that lead to on-off switching of the superconducting state. For S widths on the order of the superconducting coherence length ξ0, noncollinear magnetization orientations in adjacent F layers with multiple spin axes leads to a rich variety of triplet spin-valve effects. Motivated by recent experiments, we focus on samples where the magnetizations in the F1 and F4 layers exist in a fully spin-polarized half-metallic phase, and calculate the superconducting transition temperature, spatially and energy resolved density of states, and the spin-singlet and spin-triplet superconducting correlations. Our findings demonstrate that superconductivity in these devices can be completely switched on or off over a wide range of magnetization misalignment angles due to the generation of equal-spin and opposite-spin triplet pairings.

  3. Fullerides - Superconductivity at the limit

    NARCIS (Netherlands)

    Palstra, Thomas T. M.

    The successful synthesis of highly crystalline Cs3C60, exhibiting superconductivity up to a record temperature for fullerides of 38 K, demonstrates a powerful synthetic route for investigating the origin of superconductivity in this class of materials.

  4. Fast superconducting magnetic field switch

    Science.gov (United States)

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  5. Fast superconducting magnetic field switch

    International Nuclear Information System (INIS)

    Goren, Y.; Mahale, N.K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs

  6. Superconductivity in compensated and uncompensated semiconductors

    Directory of Open Access Journals (Sweden)

    Youichi Yanase and Naoyuki Yorozu

    2008-01-01

    Full Text Available We investigate the localization and superconductivity in heavily doped semiconductors. The crossover from the superconductivity in the host band to that in the impurity band is described on the basis of the disordered three-dimensional attractive Hubbard model for binary alloys. The microscopic inhomogeneity and the thermal superconducting fluctuation are taken into account using the self-consistent 1-loop order theory. The superconductor-insulator transition accompanies the crossover from the host band to the impurity band. We point out an enhancement of the critical temperature Tc around the crossover. Further localization of electron wave functions leads to the localization of Cooper pairs and induces the pseudogap. We find that both the doping compensation by additional donors and the carrier increase by additional acceptors suppress the superconductivity. A theoretical interpretation is proposed for the superconductivity in the boron-doped diamond, SiC, and Si.

  7. New world of Gossamer superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Kazumi; Haas, Stephan; Parker, David [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (United States); Won, Hyekyung [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str. 38, 01187, Dresden (Germany); Department of Physics, Hallym University, Chuncheon 200-702 (Korea); Dora, Balazs; Virosztek, Attila [Department of Physics, Budapest University of Technology and Economics, 1521 Budapest (Hungary)

    2006-09-15

    Since the discovery of the high-T {sub c} cuprate superconductor La{sub 2-x}BaCuO{sub 4} in 1986 by Bednorz and Mueller, controversy regarding the nature or origin of this remarkable superconductivity has continued. However, d-wave superconductivity in the hole-doped cuprates, arising due to the anti-paramagnon exchange, was established around 1994. More recently we have shown that the mean field theory, like the BCS theory of superconductivity and Landau's Fermi liquid theory are adequate to describe the cuprates. The keys for this development are the facts that a) the pseudogap phase is d-wave density wave (dDW) and that the high-T{sub c} cuprate superconductivity is gossamer (i.e. it exists in the presence of dDW). (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Earlier and recent aspects of superconductivity

    International Nuclear Information System (INIS)

    Bednorz, J.G.; Muller, K.A.

    1990-01-01

    Contemporary knowledge of superconductivity is set against its historical background in this book. First, the highlights of superconductivity research in the twentieth century are reviewed. Further contributions then describe the basic phenomena resulting from the macroscopic quantum state of superconductivity (such as zero resistivity, the Meissner-Ochsenfeld effect, and flux quantization) and review possible mechanisms, including the classical BCS theory and the more recent alternative theories. The main categories of superconductors - elements, intermetallic phases, chalcogenides, oxides and organic compounds - are described. Common features and differences in their structure and electronic properties are pointed out. This overview of superconductivity is completed by a discussion of properties related to the coherence length

  9. Direct measurement of elastic modulus of Nb 3Sn using extracted filaments from superconducting composite wire and resin impregnation method

    Science.gov (United States)

    Hojo, M.; Matsuoka, T.; Hashimoto, M.; Tanaka, M.; Sugano, M.; Ochiai, S.; Miyashita, K.

    2006-10-01

    Young's modulus of Nb3Sn filaments in Nb3Sn/Cu superconducting composite wire was investigated in detail. Nb3Sn filaments were first extracted from composite wire. Nitric acid and hydrofluoric acid were used to remove copper stabilizer, Nb3Sn/Nb barrier and bronze. Then, Nb3Sn filaments were impregnated with epoxy resin to form simple filament bundle composite rods. A large difference in Young's moduli of filaments and epoxy resin enhance the accuracy of the measurement of Nb3Sn filament modulus. The ratio of Nb3Sn to Nb in filaments and the number of filaments in the fiber bundle composite rods were used in the final calculation of the Young's modulus of Nb3Sn. The obtained modulus of 127 GPa was the lower bound of the already reported values.

  10. Direct measurement of elastic modulus of Nb3Sn using extracted filaments from superconducting composite wire and resin impregnation method

    International Nuclear Information System (INIS)

    Hojo, M.; Matsuoka, T.; Hashimoto, M.; Tanaka, M.; Sugano, M.; Ochiai, S.; Miyashita, K.

    2006-01-01

    Young's modulus of Nb 3 Sn filaments in Nb 3 Sn/Cu superconducting composite wire was investigated in detail. Nb 3 Sn filaments were first extracted from composite wire. Nitric acid and hydrofluoric acid were used to remove copper stabilizer, Nb 3 Sn/Nb barrier and bronze. Then, Nb 3 Sn filaments were impregnated with epoxy resin to form simple filament bundle composite rods. A large difference in Young's moduli of filaments and epoxy resin enhance the accuracy of the measurement of Nb 3 Sn filament modulus. The ratio of Nb 3 Sn to Nb in filaments and the number of filaments in the fiber bundle composite rods were used in the final calculation of the Young's modulus of Nb 3 Sn. The obtained modulus of 127 GPa was the lower bound of the already reported values

  11. Superconducting devices at Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Dahl, P.F.

    1978-04-01

    The various ongoing programs in applied superconductivity supported by BNL are summarized, including the development of high field ac and dc superconducting magnets for accelerators and other applications, of microwave deflecting cavities for high energy particle beam separators, and of cables for underground power transmission, and materials research on methods of fabricating new superconductors and on metallurgical properties affecting the performance of superconducting devices

  12. Superconductivity and macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Rogovin, D.; Scully, M.

    1976-01-01

    It is often asserted that superconducting systems are manifestations of quantum mechanics on a macroscopic scale. In this review article it is demonstrated that this quantum assertion is true within the framework of the microscopic theory of superconductivity. (Auth.)

  13. Superconductivity in heavily boron-doped silicon carbide

    Directory of Open Access Journals (Sweden)

    Markus Kriener, Takahiro Muranaka, Junya Kato, Zhi-An Ren, Jun Akimitsu and Yoshiteru Maeno

    2008-01-01

    Full Text Available The discoveries of superconductivity in heavily boron-doped diamond in 2004 and silicon in 2006 have renewed the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a closely related system: heavily boron-doped silicon carbide. The sample used for that study consisted of cubic and hexagonal SiC phase fractions and hence this led to the question which of them participated in the superconductivity. Here we studied a hexagonal SiC sample, free from cubic SiC phase by means of x-ray diffraction, resistivity, and ac susceptibility.

  14. Design and Test of a Thermal Triggered Persistent Current System using High Temperature Superconducting Tapes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Keun [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Kang, Hyoungku [Electro-Mechanical Research Institute, Hyundai Heavy Industries, Yongin (Korea, Republic of); Ahn, Min Cheol [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Yang, Seong Eun [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Yoon, Yong Soo [Department of Electrical Engineering, Ansan College of Technology, 671 Choji-Dong, Danwon-Gu, Ansan, 425-792 (Korea, Republic of); Lee, Sang Jin [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Ko, Tae Kuk [Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of)

    2006-06-01

    A superconducting magnet which is operated in persistent current mode in SMES, NMR, MRI and MAGLEV has many advantages such as high uniformity of magnetic field and reduced thermal loss. A high temperature superconducting (HTS) persistent current switch (PCS) system was designed and tested in this research. The HTS PCS was optimally designed using two different HTS tapes, second generation coated conductor (CC) HTS tape and Bi-2223 HTS tape by the finite element method (FEM) in thermal quench characteristic view. The CC tape is more prospective applicable wire in these days for its high n value and critical current independency from external magnetic field than Bi-2223 tape. Also a prototype PCS system using Bi-2223 tape was manufactured and tested. The PCS system consists of a PCS part, a heater which induces the PCS to quench, and a superconducting magnet. The test was performed in various conditions of transport current. An initial current decay appeared when the superconducting magnet was energized in a PCS system was analyzed. This paper would be foundation of HTS PCS researches.

  15. A study on metastable superconducting magnets

    International Nuclear Information System (INIS)

    Koyama, Kenichi

    1976-01-01

    It is important to construct superconducting magnets as cheap as possible. One of the methods to achieve such a purpose is to save the superconducting material and operate the magnets at a high current density. Therefore it is useful to investigate the requirements for the operation of metastable superconducting magnets which can work at a current higher than the recovery current. Using the theory of flux jump, we introduce a ''stable current'' below which no flux jump can occur. On a rough approximation, it is given by I sub(s) =√A P sub(i) H sub(e) T sub(o) f(x)/rho where A : cross-section of the composite conductor. P sub(i) : total perimeter of all the superconducting cores. h sub(e) : effective heat transfer coefficient to the liquid helium through the stabilizer. T sub(o) : a characteristic temperature of the superconducting cores. f(x) : a characteristic function for the relative core radius x. rho : effective resistivity of the composite. Then it is shown that superconducting magnets can operate without unexpected normal transitions in the region enclosed by the two curves of I sub(s) and I sub(c). Next, we discuss the characteristics of our saddle shaped superconducting magnet for an one-KW MHD generator. We found that, 1) the magnet does safely operate in the metastable state; 2) the characteristics of the magnet are consistent with our theoretical results. (auth.)

  16. Thermal expansion of coexistence of ferromagnetism and superconductivity

    International Nuclear Information System (INIS)

    Hatayama, Nobukuni; Konno, Rikio

    2010-01-01

    The temperature dependence of thermal expansion of coexistence of ferromag-netism and superconductivity below the superconducting transition temperature T cu of a majority spin conduction band is investigated. Majority spin and minority spin superconducting gaps exist in the coexistent state. We assume that the Curie temperature is much larger than the superconducting transition temperatures. The free energy that Linder et al. [Phys. Rev. B76, 054511 (2007)] derived is used. The thermal expansion of coexistence of ferromagnetism and superconductivity is derived by the application of the method of Takahashi and Nakano [J. Phys.: Condens. Matter 18, 521 (2006)]. We find that we have the anomalies of the thermal expansion in the vicinity of the superconducting transition temperatures.

  17. Superconductivity in multilayer perovskite. Weak coupling analysis

    International Nuclear Information System (INIS)

    Koikegami, Shigeru; Yanagisawa, Takashi

    2006-01-01

    We investigate the superconductivity of a three-dimensional d-p model with a multilayer perovskite structure on the basis of the second-order perturbation theory within the weak coupling framework. Our model has been designed with multilayer high-T c superconducting cuprates in mind. In our model, multiple Fermi surfaces appear, and the component of a superconducting gap function develops on each band. We have found that the multilayer structure can stabilize the superconductivity in a wide doping range. (author)

  18. A statistical rationale for establishing process quality control limits using fixed sample size, for critical current verification of SSC superconducting wire

    International Nuclear Information System (INIS)

    Pollock, D.A.; Brown, G.; Capone, D.W. II; Christopherson, D.; Seuntjens, J.M.; Woltz, J.

    1992-03-01

    The purpose of this paper is to demonstrate a statistical method for verifying superconducting wire process stability as represented by I c . The paper does not propose changing the I c testing frequency for wire during Phase 1 of the present Vendor Qualification Program. The actual statistical limits demonstrated for one supplier's data are not expected to be suitable for all suppliers. However, the method used to develop the limits and the potential for improved process through their use, may be applied equally. Implementing the demonstrated method implies that the current practice of testing all pieces of wire from each billet, for the purpose of detecting manufacturing process errors (i.e. missing a heat-treatment cycle for a part of the billet, etc.) can be replaced by other less costly process control measures. As used in this paper process control limits for critical current are quantitative indicators of the source manufacturing process uniformity. The limits serve as alarms indicating the need for manufacturing process investigation

  19. Crystalline color superconductivity

    International Nuclear Information System (INIS)

    Alford, Mark; Bowers, Jeffrey A.; Rajagopal, Krishna

    2001-01-01

    In any context in which color superconductivity arises in nature, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with nonzero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde, and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. Unlike the original LOFF state, these crystalline quark matter condensates include both spin-zero and spin-one Cooper pairs. We explore the range of parameters for which crystalline color superconductivity arises in the QCD phase diagram. If in some shell within the quark matter core of a neutron star (or within a strange quark star) the quark number densities are such that crystalline color superconductivity arises, rotational vortices may be pinned in this shell, making it a locus for glitch phenomena

  20. Fabrication and testing of a superconducting coil: Phase 3 of the Maglev development program

    Energy Technology Data Exchange (ETDEWEB)

    Fife, A A; Lee, S; Tillotson, M [CTF Systems Inc., Port Coquitlam, BC (Canada)

    1989-03-01

    This report documents developmental research on superconducting magnet technology suitable for the levitation and propulsion units of the Canadian Maglev vehicle. The contract work involved the design, fabrication and testing of a racetrack coil fabricated using epoxy-impregnated windings of copper stabilized NbTi wire. The following results were achieved: successful fabrication and testing of a superconducting racetrack magnet with strength {gt} 400,000 A-turns integrated in a support frame; selection and characterization of cryogenic strain gauges; characterization of strain in solenoidal and racetrack superconducting magnets; design, fabrication and testing of high current persistent switches; and operation of superconducting magnets in persistent mode. The racetrack coil reached the design current after the third quench and short sample critical current after the eighth quench. This behavior is essentially identical to that observed with a superconducting solenoid fabricated during a previous phase. The strain measured perpendicular to the straight sides of the racetrack coil was proportional to the square of the energizing current. Persistent switches were fabricated, one type with low resistance (10{sup -2} ohm) and the other with high resistance (1.2 ohm) in their normal states. The low resistance switch could be operated in 1-Tesla fields with stabel characteristics up to about 800A drive current and the high resistance switch to 475A.