Abstract: A high temperature oxide superconducting wire is provided which is capable of preventing metal located on the outer periphery of the superconducting wire from diffusing into a superconductor to achieve restriction of reduction in the critical current density. The high temperature oxide superconducting wire includes a high temperature oxide superconductor 1, a sheathing body 2 formed of material containing silver for coating the high temperature oxide superconductor 1, a heat-resistant oxide ceramic material 3 for coating the sheathing body 2, and a coating body 4 which is inactive relative to the heat-resistant oxide ceramic material 3 in a high temperature oxidative atmosphere.

Abstract: A composite superconducting tape including a plurality of stacked and diffusion-bonded superconducting. Each of the superconducting tapes includes a filament of superconducting material in a silver-silver alloy cladding. Each of the superconducting tapes are an elongate component extending longitudinally.

Abstract: A method of producing multifilament superconducting Nb3Sn wire with low bridging potential during reaction by introducing a diffusion/reaction barrier between the filaments as a radial sheet. The barrier is made of Ta, Va, a NbTa alloy or other ductile material.

Abstract: The invention features a superconducting ceramic conductor for use in a preselected fluid cryogen. The conductor includes a composite ceramic superconducting wire having an outer surface along its length and a sealing structure hermetically surrounding the outer surface to prevent the cryogen from infiltrating into the wire and degrading its superconducting properties. The sealing. structure includes a cured polymer layer encircling the outside surface of the wire.

Abstract: This invention relates to a practical superconducting conductor based upon biaxially textured high temperature superconducting coatings. In particular, methods for producing flexible and bend strain-resistant articles and articles produced in accordance therewith are described which provide improved current sharing, lower hysteretic losses under alternating current conditions, enhanced electrical and thermal stability and improved mechanical properties between otherwise isolated films in a coated high temperature superconducting (HTS) wire. Multilayered materials including operational material which is sensitive to bend strain can be constructed, in which the bend strain in the region in which such operational material is located is minimized. The invention also provides a means for splicing coated tape segments and for termination of coated tape stack ups or conductor elements.

Abstract: A High-Temperature Superconducting (HTS) transmission cable based on the cold dielectric concept with an HTS shield makes it possible to house all three phases inside a single cryostat without causing large degradation and loss due to magnetic fields generated by the neighboring phases. A further optimization is realized by making the three phases concentric to each other. No shielding layer is required in such a tri-axial configuration. It is more compact and requires only about half of the HTS tapes as that of three separately shielded phases. Each phase advantageously consists of two layers of BSCCO-2223 HTS tapes.

Abstract: A fully transposed composite superconductor can be especially used for AD devices and contains subconductors composed according to the Roebel bar principle and containing TC superconducting material. Superconductors are provided, that can be laterally bent in the plain of their width B so that the bending radius R is more than 100 times the width B and the bending zone length Hsue et al. '352 publication is more than 20 times the width B. The device for producing the conductor includes devices disposed in series for combining, bending, assembling to a Roebel bar, and fixating the subcontractors.

Abstract: A high temperature superconducting composite rod, wire or tape is formed by filling the open cells of a reticulated foam structure made of silver, silver alloy, gold or gold alloy with a superconducting ceramic oxide or precursor, compacting the filled structure and forming it into a rod, wire or tape and heating it to melt and/or texture the superconducting ceramic oxide. The resulting composite has continuous ligaments of metal throughout a continuous region of superconducting ceramic oxide.

Abstract: By rapidly heating a precursor wire having a multifilamentary structure in which multiple composite cores in which a composite compound of an Nb—Ga compound and Nb is embedded in Nb are embedded in Nb, Ta, Nb-base alloy or Tabase alloy as a matrix material to a temperature range of 1400 to 2100° C. in 2 seconds, quenching the precursor wire at a rate of 5000° C./second or larger, and subjecting the precursor wire to additional heat treatment at a temperature range of 600 to 850° C. for 1 to 400 hours, a superconducting wire having a multifilamentary structure in which multiple composite cores in which a composite compound containing Nb3Ga of a stoichiometric composition embedded in Nb are embedded in Nb, Ta, Nb-base alloy or Tabase alloy as a matrix material is obtained.

Abstract: A process for manufacturing superconducting magnetic coils from strain-tolerant, superconducting multi-filament composite conductors is described. The method involves winding the precursor to a multi-filament composite conductor and an insulating material or its precursor around a mandrel in order to form a coil, and then exposing the coil to high temperatures and an oxidizing environment. The insulating material or its precursor is chosen to permit exposure of the superconductor precursor filaments to the oxidizing environment, and to encase the matrix-forming material enclosing the filaments, which is reversibly weakened during processing.

Abstract: A composite superconducting tape which includes at least one constituent superconducting tape that may be a multiplicity of stacked and bonded tapes including a pair of exposed opposite major faces, and at least one outer layer of metal tape overlying and bonded to one of the exposed major faces. In the case where two outer layer metal tapes are included, the strength thereof differ.

Abstract: The cross section of a wire is round and is composed of several units, each consisting of tape-like superconductors laminated in an approximately rhombic shape, which are arranged such that they form a hexagon as a whole. Oxide superconducting tape wires each consisting of a plurality of oxide superconducting filaments are arranged in rotational symmetry to a core. The oxide superconducting filaments have the cross section such that the average thickness is 3 to 20 &mgr;m and the average aspect ratio is larger than 2 and smaller than 10. A step of arranging the oxide superconducting tape-like wires in rotational symmetry is accomplished when the multi-core tape-like wires are packed in a third metal pipe which becomes a metal sheath later. Since the multi-core tape wires having oxide superconducting filaments are arranged in rotational symmetry, the oxide superconductor in the oxide superconducting filaments permits its c axis to orient in various directions.

Abstract: The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

Abstract: Superconducting cables and magnetic devices are disclosed.

Abstract: Provided are an oxide superconducting wire which maintains a high critical current density and has a small current drift with small ac loss when the same carries an alternating current and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires. The oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor, and is characterized in that the flat-molded stranded wire has a rectangular sectional shape, and a section of each strand forming the flat-molded stranded wire has an aspect ratio (W1/T1) of at least 2. The method of preparing this oxide superconducting wire comprises the steps of preparing a stranded wire by twisting a plurality of strands, each of which is formed by metal-coating an oxide superconductor or raw material powder therefor, flat-molding the prepared stranded wire, and repeating rolling and a heat treatment of at least 800° C.

Abstract: A superconducting cable includes a core material, conductor layers formed by means of helically winding superconducting wires around the core material, electrically insulating layers, and magnetic shielding layers formed by means of helically winding superconducting wires around each of the electrically shielding layers. The superconducting wire is wound at the shortest pitch on the outermost conductor layer and is wound at the longest pitch on the outermost magnetic shielding layer.

Abstract: The invention relates a powder in tube type method of making an HTc superconductive multifilament strand having a silver-based matrix, in which: a first envelope is filled with powder reagents for an HTc superconductor; the resulting billet is drawn down into a monofilament strand; said monofilament strand is cut up into lengths and a secondary envelope is filled with the resulting lengths, thereby making a multifilament billet which is drawn down into a multifilament strand; said multifilament strand is cut up into lengths and a new envelope is filled with the resulting lengths, thereby making a new multifilament billet which is drawn down into a new multifilament strand; and it is shaped and subjected to heat treatment; according to the invention, at least one face of the monofilament strand is electrically insulated; and during the first multifilament step the secondary envelope is filled with the resulting insulated lengths.

Abstract: A superconducting joint between multifilamentary superconducting wires through an optional superconducting medium where at least one of such components is an interconnected filament superconducting part is disclosed. Such joint and method for producing same can include a bridge made of a superconducting medium to contact and make electrical connection with the side of such wire.

Abstract: A multi-layer passivation barrier (24) for, and a method of, passivating a superconducting layer (22) of a microelectronic device (20). The passivation barrier includes a passivating layer (32) and a barrier buffering layer (30). The passivating layer provides a barrier to moisture, salts, alkali metals and the like located outside the device. The passivating layer also provides a barrier to outdiffusion of oxygen from the superconducting layer. The buffering layer permits oxygen to diffuse therethrough and provides a barrier to prevent diffusion of one or more constituent chemical elements of the passivating layer into the superconducting layer. The method includes the steps of depositing the barrier buffering layer (30) onto the superconducting layer (22) and depositing the passivating layer (32) onto the buffering layer.

Abstract: The present invention is for a compact superconducting power transmission cable operating at distribution level voltages. The superconducting cable is a conductor with a number of tapes assembled into a subconductor. These conductors are then mounted co-planarly in an elongated dielectric to produce a 3-phase cable. The arrangement increases the magnetic field parallel to the tapes thereby reducing ac losses.

Abstract: A superconducting cable (1) for high power with at least one phase comprises a superconducting core (2) wherein a plurality of elements (3) are housed, which are structurally independent and magnetically uncoupled, each of which includes—for each phase—a couple of phase and neutral coaxial conductors, each formed by at least a layer of superconducting material, electrically insulated from one another by interposition of a dielectric material (8). Thanks to the distribution of the superconducting material into several coaxial conductive elements (3), the cable (1) allows to transmit high current amounts in conditions of superconductivity, while using a high-temperature superconducting material sensitive to the magnetic field.

Abstract: The present invention provides an oxide superconducting wire including a component provided in the form of a tape and a metal tape. The component in the form of a tape has an oxide superconducting member and a metal coating member formed mainly of silver and coating a surface of the oxide superconducting member. The metal tape, bonded in a heat treatment (e.g., fusion- or diffusion-bonded) to a surface of the component in the form of a tape, does not contain any superconducting material and it is formed mainly of silver and it also contains at least one component other than silver.

Abstract: A multifilamentary oxide superconducting wire having a low aspect ratio and a relatively high critical current density, and being suitable for a stranded wire. In order to produce such a wire, a tape-shaped, multifilamentary oxide superconducting wire prepared by the powder-in-tube process is cut along its length. The resulting multifilamentary oxide superconducting wires have a width smaller than that of the tape-shaped wire. The resulting wires typically have an aspect ratio of one to two. The filaments of the resulting wires are in the shape of a ribbon extending in the longitudinal direction, and arranged substantially parallel to each other and in layers. The filaments have an aspect ratio greater than two. The filaments inside include a filament having a portion substantially not covered with the stabilizer.

Abstract: The present invention provides a method to prepare a (Bi,Pb)SrCaCuO-2223 superconducting wire with improved critical current density at reduced cost. In general, the basic method according to the present invention comprises the steps of: (a) preparing a starting precursor powder with the oxygen content adjusted to the value of the final 2223 phase; (b) filling the starting powder into a metal sheath; (c) performing deformation processing on the metal sheath to form a composite wire and develop texture in the 2212 superconducting phases; (d) sealing said metal sheath so that a fixed oxygen content is maintained; (e) performing sintering to obtain the (Bi,Pb)SrCaCuO-2223 phase. The method uses metals other than a silver-based material in the sheath material, thus significantly reducing the materials cost of the (Bi,Pb)SrCaCuO-2223 superconducting wire.

Abstract: The present invention relates to an oxide superconducting wire. The wire has a filament made essentially of an oxide superconductor, and a stabilizing metal covering the oxide superconductor. The stabilizing metal includes a silver alloy having at least either higher mechanical strength or higher specific electrical resistance than that of silver. In one embodiment, the stabilizing metal further includes a first portion directly covering the oxide superconductor and a second portion covering the first portion. The first portion is adapted to prevent the component of the second portion from diffusing into and reacting with the oxide superconductor. The first and second portions have different materials, and the first portion is made essentially of an Ag—Sb alloy. In another embodiment, the stabilizing metal further has a first portion directly covering the oxide superconductor, a second portion covering the first portion and a third portion covering the second portion.

Abstract: A composite superconductor having an interior component of multiple filaments of superconducting Bi-2223 sheathed in a Ag or Ag alloy material, and a RE, TI or Hg based superconductor surrounding the interior component.

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

Abstract: In order to provide a flexible oxide superconducting cable which is reduced in AC loss, tape-shaped superconducting wires covered with a stabilizing metal are wound on a flexible former. The superconducting wires are preferably laid on the former at a bending strain of not more than 0.2%. In laying on the former, a number of tape-shaped superconducting wires are laid on a core member in a side-by-side manner, to form a first layer. A prescribed number of tape-shaped superconducting wires are laid on top of the first layer in a side-by-side manner, to form a second layer. The former may be made of a metal, plastic, reinforced plastic, polymer, or a composite and provides flexibility to the superconducting wires and the cable formed therewith.

Abstract: Oxide bronze compositions and articles manufactured in accordance therewith are provided. The oxide bronze compositions have the general formula AxBOy, in which A comprises an alkali, alkaline earth or rare earth metal and in which A has a valence, m, equal to 1, 2 or 3, B comprises a transition metal having a valence, n, less than or equal to 6,0<x<1 on an atomic ratio basis and y=[(x)(m)+n]/2. High temperature superconducting devices incorporating such compositions are also provided. The superconducting devices include a substrate having a polycrystalline superconducting layer or filament deposited on top of or embedded in the substrate. The superconducting layer or filament is formed of the oxide bronze composition. In some embodiments, the oxide bronze layer is textured with a full-width-half-maximum of a pole figure of less than or equal to 20 degrees.

Abstract: In a multi-core-BSCCO high-temperature superconductor comprising a superconductor structure disposed in a silver enclosure, silver-enveloped superconductor filaments including a superconductive material having a metal component, and a resistive material layer disposed around the superconductor filaments and separating the superconductor filaments from each other, the resistive material layer consists of a carbonate having a metal component which is identical to a metal component included in the superconductor material.

Abstract: A superconducting cable for alternating current, comprising conductor layers formed by a plurality of tape-shaped superconducting wires wound around a center member, an electric insulating layer formed outside the conductor layers, and a plurality of shielding layers formed outside the insulating layer, wherein, the conductor layers are formed, where N is a number of layers in the conductor layers and expressed by an integer, by gradually increasing a winding pitch of conductor layers in the same direction from an inner first layer to an N/2 layer when the number of layers is even, or from an inner first layer to a (N−1)/2 layer when the number of layers is odd, and then by gradually decreasing a winding pitch of conductor layers in an opposite direction to the inner layers from a N/2+1 layer to an N layer when the number of layers is even, or from a (N+1)/2 layer to an N layer when the number of layers is odd.

Abstract: An oxide superconducting cable is provided having a plurality of strands comprised of at least one oxide superconductor filament sheathed in a ductile and conductive metal matrix and least one of said strand further comprising a substantially continuous high resistivity coating substantially surrounding said at least one strand. The strands are positioned and arranged to form a cable. The cable is prepared by (a) applying a ductile predecessor coating to a plurality of strands, each said strand comprised of at least one oxide superconductor filament or a precursor thereto sheathed in a ductile metal matrix, and the ductile predecessor capable of conversion into a high resistivity material; (b) assembling the plurality of strands into a cable; and (c ) converting the ductile predecessor into a high resistivity material, where steps (a) and (b) can be performed in any order.

Abstract: A current lead including a high-temperature superconductor and a normal conductive component is coupled to a superconducting device. Electric current is delivered through the current lead at a level above the critical current carrying capacity of the high-temperature superconductor, creating a current-sharing mode of conductance through at least part of both the superconducting component and the normal conductive component.

Abstract: A process for manufacturing superconducting magnets is described. Two conducting tapes are assembled with an insulating ceramic layer deposited between facing sides of the tapes. The tapes and the insulative refractory material are bonded together by, for example, rolling to result in a self insulating substrate tape to which superconducting composition precursors are applied for later annealing. In one aspect, the composite tape is then wound to result in a pancake coil which is exposed to high temperatures in an oxidizing environment to convert the superconducting precursors to superconducting materials. The resultant high temperature superconducting composition coil can then be used as a high temperature superconducting magnet with appropriate conducting connectors applied thereto.

Abstract: A superconducting wire having a stacked structure comprising (a) a substrate composed of an electrically conductive material, (b) an oxide superconductor material, and (c) an electrically conductive material which is substantially not reactive with said oxide superconductor material (b), wherein said electrically conductive material (c) is impregnated in said oxide superconductor material (b) by way of heat fusion such that gaps among crystal grains contained in said oxide superconductor material (b) are filled with said electrically conductive material (c). And a process for the production of said superconducting wire.

Abstract: A reduced coefficient of friction, preferably created by ideal lubrication conditions, may advantageously be employed in the breakdown deformation of a precursor to a multifilamentary superconducting composite, particularly in combination with one or more high reduction breakdown drafts, to improve composite homogeneity and significantly increase the range of deformation conditions over which dimensional tolerances and Je may be optimized. Precursor composites made by this method exhibit reduced microhardness variability and fewer and less serious transverse filament defects than composites made by prior art methods. The method comprises the steps of: first, providing a precursor article comprising a metal matrix surrounding a plurality of filaments extending along the length of the article and comprising precursors to a desired superconducting ceramic; next, roll working the precursor article during a breakdown stage at a predetermined pressure and a coefficient of friction less than about 0.

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

Abstract: A method of texturing a multifilamentary article having filaments comprising a desired oxide superconductor or its precursors by torsionally deforming the article is provided. The texturing is induced by applying a torsional strain which is at least about 0.3 and preferably at least about 0.6 at the surface of the article, but less than the strain which would cause failure of the composite. High performance multifilamentary superconducting composite articles having a plurality of low aspect ratio, twisted filaments with substantially uniform twist pitches in the range of about 1.00 inch to 0.01 inch (25 to 0.25 mm), each comprising a textured desired superconducting oxide material, may be obtained using this texturing method. If tighter twist pitches are desired, the article may be heat treated or annealed and the strain repeated as many times as necessary to obtain the desired twist pitch.

Abstract: An oxide superconducting wire of an anisotropic oxide superconductor comprises a core part of the wire and a superconducting layer enclosing the core part so that specific crystal axes of the oxide superconductor are oriented toward the core part. A method of producing a wire of an anisotropic oxide superconductor comprises the steps of arranging a metal sheath around a metal rod for forming a core part of the wire and charging powder of the oxide superconductor in a clearance between the metal sheath and the metal rod for preparing a composite material, and plastically working the composite material so that the metal sheath is larger in reduction of area than the metal rod.

Abstract: Provided are an oxide superconducting wire which maintains a high critical current density and has a small current drift with small ac loss when the same carries an alternating current and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires. The oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor, and is characterized in that the flat-molded stranded wire has a rectangular sectional shape, and a section of each strand forming the flat-molded stranded wire has an aspect ratio (W1/T1) of at least 2. The method of preparing this oxide superconducting wire comprises the steps of preparing a stranded wire by twisting a plurality of strands, each of which is formed by metal-coating an oxide superconductor or raw material powder therefor, flat-molding the prepared stranded wire, and repeating rolling and a heat treatment of at least 800° C.

Abstract: The present invention provides a (Bi,Pb)SCCO-2223 oxide superconductor composite which exhibits improved critical current density and critical current density retention in the presence of magnetic fields. Retention of critical current density in 0.1 T fields (77 K, ⊥ ab plane) of greater than 35% is disclosed. Significant improvements in oxide superconductor wire current carrying capacity in a magnetic field are obtained by subjecting the oxide superconductor composite to a post-processing heat treatment which reduces the amount of lead in the (Bi,Pb)SCCO-2223 phase and forms a lead-rich non-superconducting phase. The heat treatment is carried out under conditions which localize the lead-rich phase at high energy sites in the composite.

Abstract: A powder in tube type method of making an HTc superconductive multifilament strand having a silver-based matrix, and an HTc superconductive multifilament strand having a silver-based matrix. The method includes, prior to the monofilament step, preparing a composite multilayer material is including at least one silver-based sheet, and at least one layer of non-superconductive ceramic material that is permeable to oxygen. During the monofilament step, a thickness of composite multilayer material is interposed between first and second thicknesses of silver-based material, thereby forming the first silver-based envelope.

Abstract: A composite superconductor having an interior component of multiple filaments of superconducting Bi-2223 sheathed in a Ag or Ag alloy material, and a RE, TI or Hg based superconductor surrounding the interior component.

Abstract: A multifilamentary oxide superconducting wire having a low aspect ratio and a relatively high critical current density, and being suitable for a stranded wire, is provided. In order to produce such a wire, a tape-shaped, multifilamentary oxide superconducting wire prepared by the powder-in-tube process is cut along its length. The resulting multifilamentary oxide superconducting wires have a width smaller than that of the tape-shaped wire. The resulting wires typically have an aspect ratio of one to two. The filaments of the resulting wires are in the shape of a ribbon extending in the longitudinal direction, and arranged substantially parallel to each other and in layers. The filaments have an aspect ratio greater than two. The filaments include a filament having a portion substantially not covered with the stabilizer.

Abstract: The present invention provides superconductors capable of being used at temperatures to which the superconductor can be cooled in liquid nitrogen and of carrying current in a high critical current density in a magnetic field, and superconducting apparatuses employing the superconductors and more advantageous in costs than the conventional superconducting apparatuses. A superconducting wire is formed by combining a metallic body of a cubic aggregate structure and an oxide superconducting substance. The present invention provides superconductors, superconducting wires, superconducting magnets and applied superconducting apparatuses having a high superconducting critical current density. The applied super conducting apparatuses employing the superconductors or the superconducting wires in accordance with the present invention are able to operate when cooled in liquid nitrogen-and can be manufactured at costs lower than those of the conventional superconducting apparatuses.

Abstract: Provided is an insulated oxide superconducting cable conductor having a high critical current and a high critical current density. The insulated oxide superconducting cable conductor comprises an elongated former, a plurality of tape-shaped multifilamentary oxide superconducting wires which are wound on the former at a bending strain factor of not more than 0.5%, and a spirally wound tape-shaped insulating material covering the tape-shaped multifilamentary oxide superconducting wires. The tape-shaped multifilamentary superconducting wires are superposed on the former in layers, whereby stabilizing materials of the superposed superconducting wires are in contact with each other. The tape-shaped insulating material consists essentially of a material which is contracted at a thermal contraction rate of at least three times that of the tape-shaped multifilamentary wires by cooling from a temperature of 298 K to that of 77 K.

Abstract: Provided are an oxide superconducting wire which maintains a high critical current density and has a small current drift with small ac loss when the same carries an alternating current and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires. The oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor, and is characterized in that the flat-molded stranded wire has a rectangular sectional shape, and a section of each strand forming the flat-molded stranded wire has an aspect ratio (W1/T1) of at least 2. The method of preparing this oxide superconducting wire comprises the steps of preparing a stranded wire by twisting a plurality of strands, each of which is formed by metal-coating an oxide superconductor or raw material powder therefor, flat-molding the prepared stranded wire, and repeating rolling and a heat treatment of at least 800° C.

Abstract: A cabled conductor is provided for use in a cryogenically cooled circuit including refrigeration having a predetermined operating temperature and efficiency. The conductor includes multiple conductor strands cabled about the longitudinal axis of the conductor at a preselected cabling period, each strand including a composite of superconducting ceramic in intimate contact with conductive matrix material. Each filament has high performance regions in which the filament material is well-textured with its preferred direction aligned perpendicular to the widest longitudinal cross-section of the conductor alternating with poorly superconducting regions which are at least about half the diameter of a filament in length and in which the superconducting ceramic filament is strained by transposition in excess of its critical strain limit. In the poorly superconducting regions, the conductive matrix material provides an alternate current path.

Abstract: A low-aspect ratio multi-filament superconductor wire includes a plurality of oxide superconductor filaments arranged in an elongated wire structure. Each filament of the wire also has a low-aspect ratio. The filaments are textured such that a crystallographic c direction of each filament is aligned with a crystallographic c direction of all other filaments with the crystallographic c directions being perpendicular to the longitudinal axis of the wire structure. The invention also features a groove rolling machine for forming a low-aspect ratio multi-filament superconductor wire by texturing a precursor tape by deforming the tape to a low-aspect ratio wire by reducing a larger dimension of the tape in such a way as to prevent buckling of the tape. A superconducting cable can be formed by planetary winding a plurality of multi-filament superconductor wires.

Abstract: An oxide superconducting stranded wire having inter-strand insulation and high critical current is provided. A wire including an oxide superconducting material and a matrix covering the material and consisting essentially of silver or a silver alloy is coated with a paint containing, as a main component, an organometallic polymer such as a silicone polymer or aluminum primary phosphorus in a paint reservoir, and the paint is baked in a baking furnace via a drying furnace. A plurality of such wires with the baked paint are twined into a stranded wire, which is then heated up to a temperature necessary for sintering the oxide superconducting material. The stranded wire thus obtained through the step of sintering may have high critical current. A heat-resisting insulating coating layer may be formed by baking the paint.