KR20070093050A - Thick superconductor films with improved performance - Google Patents

Abstract

A method for producing a thick film includes disposing a precursor solution onto a substrate to form a precursor film. The precursor solution contains precursor components to a rare-earth/alkaline-earth-metal/transition-metal oxide including a salt of a rare earth element, a salt of an alkaline earth metal, and a salt of a transition metal in one or more solvents, wherein at least one of the salts is a fluoride-containing salt, and wherein the ratio of the transition metal to the alkaline earth metal is greater than 1.5. The precursor solution is treated to form a rare earth-alkaline earth-metal transition metal oxide superconductor film having a thickness greater than 0.8 Vm. solution.

Description

Superconductor thick film with improved performance {THICK SUPERCONDUCTOR FILMS WITH IMPROVED PERFORMANCE}

Cross Reference with Related Application

This application claims 35 U.S.C. Priority to co-pending US Provisional Serial No. 60 / 615,289, filed October 1, 2004, under § 119 (e), and US Provisional Serial No. 60 / 703,836, filed July 29, 2005. The provisional application of the claims, both of which are entitled "Thick Superconductor Films With Improved Performance", both of which are incorporated herein by reference.

The present application provides the following applications:

US Patent Application Serial No. 60 / 703,815, filed Jul. 29, 2005 and entitled "High Temperature Superconductive Wires and Coils";

US Patent Application Serial No. 11 / 193,262, filed Jul. 29, 2005, entitled "Architecture for High Temperature Superconductor Wire."

In which the entire contents of the following applications are incorporated herein by reference.

Field of technology

The present invention generally relates to enhancing the critical current density carrying capacity of superconducting materials. The invention also relates to a method for improving the superconducting properties of superconducting structures and rare earth metal-alkaline earth metal-transition metal oxide films.

Since the discovery of high-temperature superconducting (HTS) materials (superconductivity at temperatures above the liquid nitrogen temperature of 77 K), efforts have been made to research and develop various engineering applications using these HTS materials. In thin film superconductor devices and wires, devices in which oxide superconductors containing yttrium, barium, copper and oxygen in the basic composition of the well-known YBa ₂ Cu ₃ O _{7 -x} (hereinafter referred to as Y123 or YBCO) are used. Has made the most progress. There has also been a great advance in the rare earth element "RE" replacing Y. In biaxially textured superconductor metal oxides, for example Y123, high critical current densities have been achieved in coated conductor constructions. Such wires are often referred to as second generation HTS wires. The Y123 is therefore suitable for numerous applications, including cables, motors, generators, synchronous capacitors, transformers, current limiters, and magnetic systems for military, high energy physics, material processing, transportation, and medical applications. It is a preferred material.

Certain challenges in this field include the need for a cost-effective method of manufacturing a chemically compatible biaxial textured buffer layer, as well as the need to deposit a high critical current density (Jc) superconducting layer of sufficient thickness. With regard to the first object, it has been shown that a strained textured substrate having an epitaxial buffer layer can be produced cost effectively. As to the need to deposit thick layers of superconductor precursor compositions, a number of techniques have been evaluated. Chemical vapor deposition (CVD) is not considered a competitive method at this time due to the very high cost of precursor materials. Most physical vapor deposition (PVD) methods (e.g., pulsed laser ablation, reactive sputtering and electron beam evaporation) are known as deposition rate, Limited by control of composition, and high capital costs. Possible economical PVD methods include thermal or electron beam evaporation methods of rare earth elements, copper and barium fluoride (known as “barium fluoride” processes). This process has been shown to be faster than the direct PVD method, but the cost of capital and control system still seems too high. In addition, the deposited precursor composition must then be reacted in a separate furnace system to form an HTS film.

Solution deposition methods are also being evaluated, which have been shown to provide much lower costs since the vacuum system is excluded. Thus, the capital cost is not as high as the other methods in which the vacuum system is used, and the deposition rate is not as low as the other methods. The trifluoroacetate (TFA) solution process offers the advantages of low cost, high deposition rate, and non-vacuum processing in the precursor composition. Such processes are disclosed, for example, in US Pat. No. 5,231,074 (Cima et al.) And WO 98/58415 (published Dec. 23, 1998) and by dissolving the components of the precursor composition to obtain a solution. It is necessary to form an image. US Patent No. 5,231,074 and WO 98/58415 are incorporated herein by reference in their entirety.

Summary of the Invention

In one aspect, the present invention provides a composition that serves as a precursor to a superconducting film, which can be coated onto a large area substrate in a single application using high deposition rates to produce the desired film thickness. The precursor composition may preferably be converted to a superconducting phase through a simple thermal process. The present invention provides a method for producing a low cost, thick film precursor composition of a rare earth superconductor on a long length substrate.

In one aspect of the invention, a process for preparing a superconductor membrane comprises precursor components for rare earth-alkaline earth metal-transition metal oxides, including salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in one or more solvents. Depositing a first precursor solution on a substrate to form a precursor film, wherein at least one of the salts is a fluoride containing salt and the ratio of transition metal to alkaline earth metal is greater than 1.5; And treating the precursor film to form a rare earth-alkaline earth-transition metal oxide superconductor, wherein the total ratio of transition metal to alkaline earth metal in the precursor film is greater than 1.5 and the total thickness of the superconductor film is greater than 0.8 μm. Include.

In at least one embodiment, the process comprises treating the precursor film to form a metal oxyfluoride intermediate film comprising rare earth, alkaline earth metal and transition metal of the first precursor solution, and heating the metal oxyfluoride intermediate film to heat the rare earth- Forming an alkaline earth metal-transition metal oxide superconductor. The metal oxyfluoride film comprises yttrium, barium and copper and the barium: copper ratio of the film adjacent the substrate / metal oxyfluoride interface is about 2: 3. The metal oxyfluoride intermediate film may be heated to a temperature in the range of about 190 ° C. to about 650 ° C. to decompose the precursor components of the first precursor solution, or the film may be heated to a temperature in the range of about 190 ° C. to about 400 ° C. Obtained by decomposing the precursor components of the precursor solution. In another embodiment, the metal oxyfluoride intermediate membrane has a total pressure of about 0.1 torr to about 760 torr and about 700 ° C. in an environment that includes about 0.09 torr to about 50 torr of oxygen and about 0.01 torr to about 150 torr of water vapor. Obtained by heating at a temperature in the range from about 825 ° C.

In one or more embodiments, the ratio of transition metal to alkaline earth metal in the precursor solution or final oxide superconductor is greater than 1.6, or greater than about 1.5 to about 1.8. The transition metal may be copper and the alkaline earth metal comprises barium.

In one or more embodiments, the first precursor solution comprises at least about 5 mol% excess copper, or at least about 20 mol% excess copper.

In one or more embodiments, the first precursor solution is at least 5 mol% barium or at least 20 mol% barium.

In one or more embodiments, the first precursor solution is deposited to a thickness of greater than 1.0 μm and / or the superconductor film has a total thickness of greater than 1.0 μm.

In one or more embodiments, the first precursor solution is deposited in two or more deposition steps. The deposition of the precursor film comprises depositing a second precursor solution comprising precursor components for the rare earth-alkaline earth metal-transition metal oxide comprising salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in one or more solvents. Wherein at least one of the salts is a fluoride containing salt, the ratio of transition metal to alkaline earth metal is about 1.5 and the second precursor composition is different from the first precursor composition.

In one or more embodiments, the second precursor solution comprises one or more additive components or dopant components selected for the formation of flux pinning sites in the superconducting film. The additive component includes a soluble component that forms second phase nanoparticles under the conditions used for the treatment of the precursor film, the soluble component consisting of a compound of rare earth, alkaline earth metal, transition metal, cerium, zirconium, silver, aluminum and magnesium Is selected from. The dopant component includes a metal that partially replaces the rare earth, alkaline earth metal or transition metal of the oxide superconductor.

In one or more embodiments, the second precursor solution may be deposited prior to the deposition of the first precursor solution, or the second precursor solution may be deposited after the first precursor solution.

In one or more embodiments, the second precursor solution is deposited to form an oxide superconductor film having a total thickness of less than 0.8 μm.

In one or more embodiments, the substrate is biaxially oriented, the superconductor film is biaxially oriented and has a substantially constant c-axis orientation across its width, and the c-axis orientation of the superconductor film is substantially perpendicular to the surface of the substrate. to be.

In one or more embodiments, the first precursor solution includes one or more additive components or dopant components that are selected for the formation of flux line anchorage points in the superconducting film. The additive component includes a soluble component that forms second phase nanoparticles under the conditions used for the treatment of the precursor film, the soluble component consisting of a compound of rare earth, alkaline earth metal, transition metal, cerium, zirconium, silver, aluminum and magnesium Is selected from. The dopant component includes a metal that partially replaces the rare earth, alkaline earth metal or transition metal of the oxide superconductor.

In another aspect of the present invention, a process for preparing a superconductor film includes a first precursor solution comprising a salt of a transition metal in at least one solvent, a salt of a rare earth element, a salt of an alkaline earth metal, and a transition metal in at least one solvent. Placing a second precursor solution comprising precursor components for the rare earth-alkaline earth-metal transition metal oxide comprising a salt on the substrate in any order to form a precursor film, wherein at least one of the salts contains fluoride Salt, and the ratio of transition metal to alkaline earth metal is at least 1.5; And treating the precursor film to form a rare earth-alkaline earth metal-transition metal oxide superconductor, wherein the total ratio of transition metal to alkaline earth metal in the precursor film is greater than 1.5 and the total thickness of the superconductor film is greater than 0.8 μm or greater than 1.0 μm. It comprises a step. Treating the precursor film includes treating the precursor film to form an intermediate film comprising rare earth, alkaline earth metal, and transition metal of the first and second precursor solutions; And heating the intermediate film to form a rare earth-alkaline earth metal-transition metal oxide superconductor.

In one or more embodiments, the precursor film is heated after deposition of each precursor solution to form an intermediate film comprising the metal component of the precursor solution.

In one or more embodiments, the total ratio of transition metal to alkaline earth metal is in the range of greater than 1.6, or greater than about 1.5 to about 1.8. Transition metals include copper and alkaline earth metals include barium.

In one or more embodiments, the first precursor solution is predominantly made of copper.

In one or more embodiments, the first precursor solution is deposited before the second precursor.

In one or more embodiments, the second precursor solution has a copper to barium ratio of about 1.5 and the second precursor solution has a copper to barium ratio greater than 1.5.

In one or more embodiments, the second precursor further comprises at least one of an additive component and a dopant component selected for the formation of a pinning center.

In one or more embodiments, the method includes disposing a copper solution on a substrate to form a copper precursor layer; And disposing a second precursor solution comprising salts of yttrium, barium and copper on the copper precursor layer, wherein the ratio of copper to barium is at least 1.5.

In one or more embodiments, the substrate is biaxially oriented, the superconductor film is biaxially oriented and has a substantially constant c-axis orientation across its width, and the c-axis orientation of the superconductor film is substantially perpendicular to the surface of the substrate. to be.

In another aspect of the invention, an article comprises a biaxial textured substrate having a superconducting layer thereon, wherein the superconducting layer comprises a rare earth barium copper oxide superconductor, the superconducting layer having a thickness of greater than 0.8 μm, Cu The ratio of Ba to 1.5 is greater than 1.5, and the superconducting layer comprises fluoride. The ratio of copper to barium may be greater than 1.6 and / or the superconductor film is greater than 1.0 μm in thickness.

In one or more embodiments, the substrate comprises a material selected from the group consisting of cerium oxide, lanthanum aluminum oxide, lanthanum manganese oxide, strontium titanium oxide, magnesium oxide, neodymium gadolinium oxide, and / or cerium oxide / yttria-stabilized zirconia. It includes a buffer layer.

In one or more embodiments, the superconducting layer has a critical current density of at least 200 Amps / cmW at a temperature of 77 K.

In another aspect of the invention, a metal oxyfluoride film comprises an oxyfluoride film on a substrate, the film comprising one or more rare earth elements, one or more alkaline earth metals and one or more transition metals, wherein the thickness of the film is greater than 0.8 μm. , The ratio of transition metal to alkaline earth metal is greater than 1.5, and the ratio of barium: copper of the film adjacent the substrate / metal oxyfluoride interface is about 2: 3. The ratio of copper to barium may be greater than 1.6 and / or the thickness of this film is greater than 1.0 μm.

In one or more embodiments, the substrate comprises a material selected from the group consisting of cerium oxide, lanthanum aluminum oxide, lanthanum manganese oxide, strontium titanium oxide, magnesium oxide, neodymium gadolinium oxide, and cerium oxide / yttria-stabilized zirconia. It includes a buffer layer.

In another aspect of the invention, the superconductor membrane is adapted to adjust the ratio of transition metal to alkaline earth metal in the precursor solution, wherein the ratio of transition metal to alkaline earth metal is greater than 1.5; Depositing a precursor solution onto the substrate to form a precursor film; And decomposing the precursor film to achieve a ratio of about 1.5 transition metal to alkaline earth metal of the film adjacent the interface between the precursor film and the substrate, wherein the total ratio of transition metal to alkaline earth metal in the superconductor film is 1.5. And the total thickness of the superconductor film is greater than 0.8 μm.

In one or more embodiments, adjusting the ratio of transition metal to alkaline earth metal includes increasing the content of transition metal in the precursor solution.

In one or more embodiments, the content of transition metal in the precursor solution is increased by at least 5% or at least 20%.

In one or more embodiments, adjusting the ratio of transition metal to alkaline earth metal comprises reducing the content of alkaline earth metal in the precursor solution.

In one or more embodiments, the content of alkaline earth metal in the precursor solution is reduced by at least 5% or at least 20%.

Brief description of the drawings

The invention is described with reference to the following drawings, which are given for illustrative purposes only and are not intended to limit the invention.

1 is a schematic view of a superconducting article according to the present invention.

FIG. 2 shows the Ic dependence of the Y123 (YBCO) film on the oxide-buffered metal substrate as a function of magnetic field and temperature.

FIG. 3 shows Ic as a function of field orientation of the YBCO film on the oxide-buffered metal substrate.

4 is a schematic diagram of a system and process used to make textured patterned oxide superconductor wires in accordance with one or more embodiments of the present invention.

5 shows Ic as a function of adding excess Cu to YBCO.

FIG. 6 shows Ic as a function of spin rate in addition Cu precursor solution.

FIG. 7 shows measured Ic for the bilayer of the YBCO film comprising excess Cu in the second layer and the bilayer of the YBCO film.

)에 대한 임계 전류 (Ic)의 도면이다.8 shows the magnetic field orientation at 1 Tesla and 77 K of the HTS wire described in Example 9.

Is a diagram of the threshold current Ic).

Detailed description of the invention

Precursor compositions and methods are described for forming a biaxially textured superconducting oxide film from a precursor composition by depositing a precursor composition of a superconducting material on a substrate, directly on a substrate, or on a buffer- and / or intermediate-coated substrate. . The precursor composition includes components that are salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in one or more solvents.

1 illustrates one embodiment of an HTS coated conductor. Referring to FIG. 1, high temperature superconductor (HTS) articles, in particular in the form of wires or tapes, generally have a surface 12, at least one epitaxial buffer layer 13, and a rare earth-alkaline earth metal-transition. At least one biaxially-assembled substrate 11 comprising an upper layer 14 of a c-axis oriented superconducting layer aligned in-plane of the metal oxide superconductor (RE-123). Although the methods and compositions described herein generally apply to all RE-123 superconductors, the methods and articles are illustrated with reference to YBCO. Metal substrates such as Ni, Ag, or Ni alloys provide flexibility in articles and can be fabricated over long lengths and large areas. The metal oxide layer, for example LaAlO ₃ , Y ₂ O ₃ , CeO ₂ , or yttria-stabilized zirconia (YSZ), constitutes the next layer and serves as a chemical barrier between the metal substrate and the active layer. do. The buffer layer (s) may be more resistant to oxidation than this substrate and may reduce the diffusion of species between the substrate and the superconductor layer. In addition, the buffer layer (s) may have a coefficient of thermal expansion that matches well with the superconductor material.

FIG. 2 shows a typical field dependence of a metal-organic deposited (MOD) YBCO film on an oxide-buffered metal substrate in a magnetic field oriented parallel or perpendicular to the plane of the film. At 75 K, in a magnetic field oriented perpendicular to the plane of the film, the critical current (Ic) is significantly reduced from the value in parallel orientation, which limits the usefulness of the Y123 wire in many coil applications. Performance improves as the temperature decreases, but many anticipated uses include temperatures in the region of 55 to 65 K in a magnetic field of 1-3 Tesla oriented perpendicular to the plane of the membrane, which is a condition where performance is significantly reduced. Is planned against. In addition to the parallel and vertical performance of the YBCO wire in the magnetic field, it is important to investigate the field performance at the intermediate angle shown in FIG. 3. As shown in FIG. 3, YBCO membranes typically exhibit small peaks on the c-axis (0 and 180 ⁰ or perpendicular to the plane of the YBCO membrane), which can be augmented through the presence of elongated planar or linear defects. (E.g. twin boundaries, grain boundaries, a-axis grains). In practical use, however, YBCO wire performance is determined by the minimum performance in H of any orientation and not by the minimum performance of the vertical orientation.

A highly oriented oxide superconducting film is obtained using a metal organic (solution based) deposition (MOD) process. The MOD process provides an attractive system because the precursor solution is variable and can change over a wide range of compositions and concentrations. In the MOD process for making a RE-123 film from a TFA precursor, the precursor solution decomposes to form a film comprising an intermediate of RE-123 (eg, a metal oxyhalide intermediate). The oxyfluoride membrane is considered to be any membrane that is a precursor to a RE-123 oxide superconductor membrane, which is (1) BaF ₂ , rare earth oxides or fluorides and / or mixtures of transition metals, transition metal oxides or transition metal fluorides (2) a compound consisting of a RE-Ba-OF phase, a mixture of rare earth oxides or fluorides and / or a transition metal oxide or fluoride, or (3) a compound consisting of a Ba-OF phase, a rare earth oxide or fluorine A mixture of a lide and / or a transition metal oxide or fluoride. The intermediate film can then be further processed to form a RE-123 oxide superconductor film.

The Rutherford Back Scattering (RBS) and nuclear activation assays on YBCO membranes prepared by the use of the TFA solution deposition method showed a distribution of cations across the thickness of the degraded metal oxyhalide intermediate membrane. Simulations for fitting RBS data show that the copper concentration is higher at the surface and lower at the buffer / YBCO interface, the barium concentration is lower at the surface and higher at the interface, and the concentration of Y penetrates the thickness. It was found to be relatively constant. Investigation by nuclear activation analysis revealed that fluorine was distributed along the thickness direction, with fluorine increasing at the interface and decreasing towards the surface. This distribution of cation concentrations in the intermediate decomposition membranes is more problematic for thick films (eg, overall film thicknesses greater than 0.8 μm) than thin films, which requires the cations to diffuse farther to redistribute during the reaction. Because there is. In contrast, all elements in the final oxide superconductor film are uniformly distributed, indicating that the elements redistribute during the final reaction of the oxyfluoride intermediate film to the oxide superconductor. Oxide superconductor membranes also exhibit small but detectable fluoride residues. Analysis of the HTS film shows an increase in the Cu concentration at the top of the film, but the bulk analysis of the film shows no substantial loss of cations from the film (ie, the concentration of metal in the degraded film is determined from the metal concentration of the precursor solution). Essentially unchanged).

In the MOD process for the production of YBCO films from TFA precursors, nucleation of YBCO at the buffer layer / metal oxyfluoride layer interface is one factor in texture development. In order to improve the results, the constituent elements should be at a nearly stoichiometric ratio at the buffer / YBCO interface, for example, almost Ba: Cu 2: 3 when nucleation occurs. In conventional processing of YBCO membranes from TFA precursors using stoichiometric precursor solutions (Y: Ba: Cu = 1: 2: 3), the heterogeneous cation distribution across the oxyfluoride membrane is stoichiometric at the buffer / YBCO interface. Get out of the rain. For example, the interface region has a copper to barium ratio of less than 1.5, and the surface of the film is greater than 1.5 in some thicker films (eg, films greater than 0.8 μm). As the film thickness increases, the variation between the Cu and Ba concentrations at the top and bottom of the film becomes even more pronounced. Lack of copper at the buffer / YBCO interface, for example, low ratios of copper to barium, can lead to poor nucleation or reduced growth kinetics of the YBCO, leading to degradation of the YBCO film. Additionally, maintaining a ratio of Cu to Ba of greater than 1.5 throughout the film thickness can improve the growth of YBCO throughout the film thickness. As used herein, the term “near stoichiometric ratio” means a ratio of alkaline earth metal to transition metal of about 2: 3 in the RE-123 membrane.

According to one or more embodiments of the present invention, the concentration of the transition metal in the precursor solution is adjusted to achieve a total ratio greater than 1.5 of the transition metal to alkaline earth metal. The overall ratio of transition metal to alkaline earth metal can be at least 1.6, or at least 1.8, or at least 2.0 or can range from 1.65-1.95. The precursor solution may be deposited in one or more layers of the same or different composition to achieve a total ratio of transition metal to alkaline earth metal of greater than 1.5 and an overall thickness of about 0.8 μm or greater than about 1.0 μm. As used herein, the term "total" means one or more entire layers deposited in the formation of the superconductor film.

YBCO films can be prepared by adjusting the Cu and Ba content in the precursor solution to achieve a total ratio of Cu to Ba greater than 1.5. The precursor film is then degraded to achieve a metal oxyfluoride film having a nearly stoichiometric Ba: Cu 2: 3 and a total ratio of Cu to Ba of greater than 1.5 in the buffer / YBCO interface region.

YBCO films can be prepared by increasing the Cu content in the precursor solution, decomposing the precursor film to achieve a nearly stoichiometric Ba: Cu 2: 3 at the buffer / YBCO interface and to achieve a total ratio of Cu to Ba greater than 1.5. . The Cu content in the precursor solution is at least about 5 mol%, or at least about 10 mol%, or at least about 20 mol%, relative to the metal content required for the preparation of the precursor solution comprising a stoichiometric ratio of constituent alkaline earth metal and transition metal, or About 5-30 mole%.

YBCO films can be prepared by reducing the Ba content in the precursor solution, decomposing the precursor film to achieve a nearly stoichiometric Ba: Cu 2: 3 in the buffer / YBCO interface region and achieving a total ratio of Cu to Ba greater than 1.5. have. The content of Ba in the precursor solution is at least about 5 mol%, or at least about 10 mol%, or at least about 20 mol%, or about 5-, relative to the metal content required for the preparation of the precursor solution comprising a stoichiometric proportion of constituent metal. 30 mol% can be reduced.

The YBCO film increases the Cu content while reducing the Ba content in the precursor solution, decomposes the precursor film to achieve a nearly stoichiometric Ba: Cu 2: 3 in the buffer / YBCO interface region and a total ratio of Cu to Ba greater than 1.5. It can be prepared by. The content of Cu in the precursor solution is at least 5 mol%, or at least about 10 mol%, or at least about 20 mol%, or about 5-30 relative to the metal content required for the preparation of the precursor solution comprising a stoichiometric ratio of the constituent metal. The molar percentage can be increased, while the Ba content in the precursor solution can be reduced by at least about 5 mole percent, or at least about 10 mole percent, or at least about 20 mole percent, or about 10-30 mole percent.

The composition of the precursor solution may be further adjusted to provide an oxide superconducting layer with improved performance while maintaining a total transition metal to alkaline earth metal ratio of greater than 1.5 in the superconducting film. For example, the presence of nanoscale defects or nanoparticles in the grains of oxide superconductors acts as a flux line center of fixation, which improves electrical performance in magnetic fields. In one aspect of the invention, a precursor component for formation of a rare earth / alkaline earth metal / transition metal oxide (hereinafter “RE-123”) having a total transition metal to alkaline earth metal ratio of greater than 1.5, and formation of a magnetic flux anchor point Precursor solutions comprising additive components and / or dopant components are used in the method of solution substrates for obtaining superconducting films having a fixed center point.

The dopant component provides a dopant metal that partially replaces the metal of the precursor component of the precursor solution. In general, the dopant component may be any metal compound that is soluble in the solvent (s) included in the precursor solution and provides a dopant metal that substitutes for the element of the oxide superconductor when processed for the formation of the oxide superconductor.

Additive components include soluble compounds of rare earths, alkaline earth metals or transition metals, cerium, zirconium, silver, aluminum, or magnesium, which can form second phase nanoparticles that act as anchor points in the oxide superconductor film. . In one or more embodiments, the additive component may include a stoichiometric excess of the soluble compound included in the precursor solution as the precursor component. For example, soluble yttrium salt may be included in the precursor solution in excess of that required for the formation of Y123. Excess yttrium may be processed according to one or more embodiments of the present invention to provide a yttrium-rich second phase nanoparticle, such as Y ₂ BaCuO ₅ (Y211), Y ₂ Cu ₂ O ₅ and / or Y ₂ O _3. And the nanoparticles serve as a particulate anchoring point in the superconducting oxide film. In general, the additive component may be any metal compound that is soluble in the solvent (s) included in the precursor solution and forms a metal oxide or metal in the oxide superconductor film. Exemplary additive components include rare earth, alkali metal or transition metal compounds other than those of the precursor component or those of the precursor component. Soluble compounds of the metal compounds used in the formation of nanoparticles are those metals, for example rare earths, such as yttrium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium Compounds of alkaline earth metals such as calcium, barium and strontium, transition metals such as scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel and zirconium, cerium, silver, aluminum, and magnesium These compounds can be dissolved in a solvent included in the precursor solution. Such compounds include, for example, salts of these metals (eg nitrates, acetates, alkoxides, halides, sulfates, and trifluoroacetates), oxides and hydroxides. The additive component may also be added to the precursor solution as a powder to form a nanoparticle dispersion.

Additional information on suitable additives and dopants for use in precursor solutions is co-pending and co-owned in the United States, entitled "Oxide Films with Nanodot Flux Pinning Centers". Patent Application No. 10 / 758,710, which is incorporated herein by reference.

The precursor layer may be deposited in a single step. For example, a precursor solution comprising the constituent metal of YBCO and having a Cu to Ba ratio greater than 1.5 is deposited to a thickness of at least 0.8 μm and the precursor film decomposes in a vapor environment to form a metal oxyfluoride film, the metal oxyfluoride. Ride films have a nearly stoichiometric Ba: Cu content of 2: 3 at the buffer / YBCO interface, a total Cu to Ba ratio of greater than 1.5, and an overall thickness of greater than 0.8 μm or greater than about 1.0 μm. The ratio of Cu to Ba in the precursor solution can be achieved using a solution comprising excess copper, barium deficient, or both, and can be at least about 5 mol%, or at least about 20 mol%. As used herein, the term “excess” refers to the amount of metal that is excess than the amount required to prepare the precursor solution comprising the constituent metals in the stoichiometric proportion of the oxide superconductor. As used herein, the term “poor” refers to the amount of metal that is deficient for the preparation of precursor solutions comprising the constituent metals in a stoichiometric proportion of oxide superconductors.

The precursor layer may be deposited in two or more steps and using two or more different precursor solutions, where one or more of these steps provide a layer comprising excess copper. The layer comprising excess copper may be deposited using a copper-rich RE-123 precursor solution including all constituent metals of the oxide superconductor, or it may be a copper-only precursor solution.

In one embodiment, the first precursor layer may be deposited and degraded on the substrate before the second precursor layer is deposited and degraded. In other embodiments, the precursor layer may be deposited in two or more steps and degraded in a single step.

In one or more embodiments, a copper containing layer may be deposited between the first and second RE-123 precursor layers. The first precursor layer may be deposited and degraded on the substrate before the copper layer is deposited. Any intermediate layer must form a textured crystalline structure that is structurally and chemically compatible with the precursor material, for example allowing the deposition of the epitaxial superconductor layer.

The intermediate layer is typically CuO or Cu ₂ O depending on the temperature. However, because this layer is a thin layer and during the conversion process at high temperatures, this copper oxide layer can diffuse into the top or bottom layer. After decomposition, this layer is observable under SEM, but after high temperature reaction to the oxide superconductor this layer is no longer observed. Since copper oxide diffuses into the matrix, the Cu content in the matrix becomes high.

The thickness of the intermediate layer is generally in the range of 20 nm to 200 nm and is deposited by, for example, a sputtering method, an evaporation deposition method or a pulsed vapor deposition method, or other conventional method. This layer may also be deposited as a soluble copper precursor, which decomposes to form copper oxide. During the heat treatment necessary for the formation of the oxide superconductor, some or all of the copper from the intermediate layer diffuses into both precursor layers to form a copper-rich superconductor layer.

In one embodiment, the YBCO film deposits a first layer of copper precursor solution and comprises a constituent metal Y, Ba, Cu in a ratio of about 1: 2: 3 (eg, stoichiometric ratio). By depositing a second layer of wherein the overall composition of both layers provides an alkaline earth metal to transition metal ratio of greater than 1.5. The precursor film decomposes in a water vapor environment, yielding a nearly stoichiometric Y: Ba: Cu at a buffer / YBCO interface, an overall Cu to Ba ratio of greater than 1.5, and an overall thickness of greater than about 0.8 μm or about 1.0 μm. Is achieved. The copper precursor solution may be deposited to provide an excess Cu content of at least about 5 mol%, or at least about 20 mol%, or at least about 30 mol%. The YBCO precursor solution may also comprise excess copper (or insufficient barium), in which case the amount of copper in the copper precursor layer is adjusted accordingly.

In another embodiment, the YBCO film comprises a layer of YBCO precursor solution with excess Cu content, a layer of Cu precursor solution, and a layer of YBCO precursor solution comprising constituent metals Y, Ba, Cu in a ratio of about 1: 2: 3. It can be prepared by depositing. The overall composition of the three layers gives a Cu: Ba ratio of greater than 1.5. Decomposition of the precursor film in a water vapor environment results in a nearly stoichiometric 1: 2: 3 Y: Ba: Cu, a total Cu to Ba ratio of greater than 1.5, and an overall thickness of greater than about 0.8 μm or about 1.0 μm at the buffer / YBCO interface. To provide. The application of multiple thick layers provides an exceptional thickness of the final YBCO film with attractive texture and current capacity.

In another embodiment, multiple layers of copper-rich (or barium-poor) YBCO precursor solution are deposited. The YBCO film deposits another YBCO layer of YBCO precursor solution with excess Cu content, another YBCO layer of precursor solution with excess Cu content, and decomposes the precursor film in a water vapor environment to yield a nearly stoichiometric 2: 3 Ba at the buffer / YBCO interface. A: Cu, an overall Cu to Ba ratio of greater than 1.5, and an overall thickness of greater than 0.8 μm. The application of multiple thick layers provides an exceptional thickness of the final YBCO film with attractive texture and current capacity.

In another embodiment, the YBCO film deposits a first layer of YBCO precursor solution with excess Cu content, a second layer of YBCO precursor solution with excess Cu (or barium-lack) content, and deposits the precursor in a vapor environment. The membrane is degraded to achieve a nearly stoichiometric Ba: Cu, total Cu to Ba ratio of greater than 1.5, and a total thickness of greater than 0.8 μm at the buffer / YBCO interface. The application of multiple thick layers provides an exceptional thickness of the final YBCO film with attractive texture and current capacity.

In another embodiment, the YBCO film deposits a first layer of YBCO precursor solution with excess Cu (or barium-lack) content and decomposes the precursor film in a water vapor environment to provide a nearly stoichiometric 2: 3 at the buffer / YBCO interface. Of the YBCO precursor solution to achieve a Ba: Cu, comprising constituent metals Y, Ba, Cu in a ratio of about 1: 2: 3 (e.g., stoichiometric) or comprising excess copper (or insufficient barium) content By depositing a second layer, where some of the yttrium is partially substituted by the dopant source, decomposing the precursor film in a vapor environment to achieve an intermediate film comprising the dopant. The total Cu to Ba ratio is greater than 1.5 and the total thickness of the intermediate layer is greater than 0.8 μm. The application of multiple thick layers provides a final YBCO film comprising a layer of exceptional thickness and comprising a flux line anchor point with attractive texture and current capacity.

In another embodiment, the YBCO film deposits a first layer of YBCO precursor solution with excess Cu (or barium-lack) content and decomposes the precursor film in a water vapor environment to provide a nearly stoichiometric 2: 3 at the buffer / YBCO interface. To form Ba: Cu and to form constituent metals Y, Ba, Cu in a ratio of about 1: 2: 3 (e.g., stoichiometric) or contain excess copper (or insufficient barium) content and form an oxide superconductor It can be prepared by depositing a second layer of YBCO precursor solution further comprising an additive or a dopant to form second phase nanoparticles under the conditions used for. The total Cu to Ba ratio is greater than 1.5 and the total thickness of the intermediate layer is greater than 0.8 μm. These layers provide films of exceptional thickness and include layers with second phase nanoparticles.

Precursor solutions with an alkaline earth metal to transition metal ratio greater than 1.5 are deposited in an amount sufficient to provide a fully reacted oxide superconductor film of a total thickness of at least 0.8 μm. This solution can be deposited to a greater thickness to provide a sufficiently reacted oxide superconductor film, for example, at least 1.0 μm, or 0.8-3.0 μm thick. By applying a plurality of layers of the precursor solution, a final thickness of up to 3 μm is prayed without a drop in texture or current capacity.

Superconducting films prepared from the precursor solutions and methods described above showed an improvement in critical current. The critical current of the superconductor film having a YBCO thickness of about 1 μm ranges from about 200 Amps / cmW to about 250 Amps / cmW.

Suitable precursor components include soluble compounds of one or more rare earth elements, one or more alkaline earth metals and one or more transition metals. As used herein, “soluble compounds” of rare earth elements, alkaline earth metals and transition metals refer to compounds of these metals that can be dissolved in a solvent included in the precursor solution. Such compounds include, for example, salts of these metals (eg, nitrates, acetates, alkoxides, halides, sulfates and trifluoroacetates), oxides and hydroxides. At least one of these compounds is a fluorine containing compound such as trifluoroacetate.

In general, rare earth metal salts are soluble in the solvent (s) included in the precursor solution and are rare earth oxide (s) (eg, Y ₂ O ₃ when processed to form intermediates (eg, metal oxyhalide intermediates). May be any rare earth metal salt that forms The rare earth element may be selected from the group of yttrium, cerium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Typically, the alkaline earth metal is barium, strontium or calcium. In general, alkaline earth metal salts are soluble in the solvent (s) included in the precursor solution and are alkaline earth metal halide compounds (eg, BaF ₂ , BaCl ₂ when processed to form intermediates (eg, metal oxyhalide intermediates). , BaBr ₂ , BaI ₂ ), which may be any alkaline earth metal salt that forms alkaline earth metal oxide (s) (eg, BaO). Generally the transition metal is copper. The transition metal salt should be soluble in the solvent (s) included in the precursor solution. In one or more embodiments of the present invention, the rare earth and alkaline earth metal elements may form metals or mixed metal oxyfluorides in place of or in addition to the rare earth oxides and alkaline earth metal fluorides.

Suitable copper precursor solutions include copper salts that are soluble at appropriate concentrations in the solvent (s). Such compounds include copper nitrate, acetates, alkoxides, halides, sulfates or trifluoroacetates. Suitable compounds are copper propionate.

In one embodiment, the precursor solution comprises yttrium, barium and copper and the ratio of Cu to Ba is greater than about 1.5. In another embodiment, the precursor solution comprises yttrium, barium and copper having a Cu to Ba ratio of at least 1.6. In another embodiment, the precursor solution comprises yttrium, barium and copper, wherein the ratio of Cu to Ba is at least 1.8.

The solvent or combination of solvents used in the precursor solution may include any solvent or combination of solvents that can dissolve metal salts (eg, metal carboxylate (s)). Such solvents include, for example, alcohols including methanol, ethanol, isopropanol and butanol.

In embodiments wherein the metal salt solution comprises trifluoroacetate ions and alkaline earth metal cations (eg, barium), the total amount of trifluoroacetate ions is fluorine (in the form of trifluoroacetate) contained in the metal salt solution. The molar ratio of alkaline earth metal (eg barium ions) to the metal salt solution is at least about 2: 1 (eg, about 2: 1 to about 18.5: 1, or about 2: 1 to about 10: 1). May be selected.

The method of disposing a superconducting composition on a base layer (e.g., on a surface of a substrate, for example a substrate having an alloy layer and having at least one buffer layer disposed thereon) may be spin coating, dip coating, slot coating. , Web coatings and other techniques known in the art. A web coating method for depositing a precursor film on an assemblage template having a structure of CeO ₂ / YSZ / Y ₂ O ₃ / NiW is shown in FIG. 4. Textured molds are provided in a width of about 1-10 cm.

As shown in FIG. 4, at the first station 410, the wire substrate is processed to obtain biaxial texture. Preferably, the substrate surface has a relatively well defined crystallographic orientation. For example, this surface may be a biaxial textured surface (eg, (113) [211] surface) or a cube textured surface (eg, (10O) [O11] surface or (10O) [OOl] surface. May be). Preferably the peak at the X-ray diffraction pole figure of the surface 110 has an FWHM of less than about 20 ^O (eg, less than about 15 ^O, less than about 10 ^O , or from about 5 ^O to). About 10 ⁰ ).

The surface can be produced, for example, by rolling and annealing. The surface may also be prepared using a vacuum process, such as ion beam assisted deposition, gradient substrate deposition, and other vacuum techniques known in the art to form biaxial textured surfaces on, for example, randomly oriented polycrystalline surfaces. Can be formed. In certain embodiments (eg, when ion beam assisted deposition is used), the surface of the substrate need not be aggregated (eg, the surface may be randomly oriented polycrystalline or the surface may be amorphous). has exist).

The substrate may be formed of any material capable of supporting the buffer layer stack and / or the layer of superconductor material. Examples of substrate materials that can be used as the substrate include, for example, metals and / or alloys such as nickel, silver, copper, zinc, aluminum, iron, chromium, vanadium, palladium, molybdenum and / or alloys thereof do. In some embodiments, the substrate may be formed of superalloy. In certain embodiments, the substrate may be in the form of an object (eg, tape or wafer) having a relatively large surface area. In such embodiments, the substrate is preferably formed of a relatively flexible material.

In some of these embodiments, the substrate is a binary alloy comprising two of the following metals: copper, nickel, chromium, vanadium, aluminum, silver, iron, palladium, molybdenum, tungsten, gold And zinc. For example, binary alloys may be formed of nickel and chromium (eg, nickel and up to 20 atomic% chromium, nickel and about 5 atomic% to about 18 atomic% chromium, or nickel and about 10 atoms % To about 15 atomic% chromium). As another example, the binary alloy may be formed of nickel and copper (eg, copper and about 5 atomic% to about 45 atomic% nickel, copper and about 10 atomic% to about 40 atomic% nickel, or Copper and about 25 atomic% to about 35 atomic% nickel). As a further example, the binary alloy may comprise nickel and tungsten (eg, from about 1 atomic% tungsten to about 20 atomic% tungsten, about 2 atomic% tungsten to about 10 atomic% tungsten, about 3 atomic% Tungsten to about 7 atomic percent tungsten, about 5 atomic percent tungsten). Binary alloys may further comprise relatively small amounts of impurities (eg, less than about 0.1 atomic percent, less than about 0.01 atomic percent, or less than about 0.005 atomic percent).

In certain such embodiments, the substrate comprises more than two metals (eg, quaternary alloys or quaternary alloys). In some such embodiments, the alloy may comprise one or more oxide formers (eg, Mg, Al, Ti, Cr, Ga, Ge, Zr, Hf, Y, Si, Pr, Eu, Gd, Tb, Dy, Ho, Lu, Th, Er, Tm, Be, Ce, Nd, Sm, Yb and / or La-Al are preferred oxide formers-) and two kinds of the following metals: copper, nickel, chromium Vanadium, aluminum, silver, iron, palladium, molybdenum, gold and zinc. In certain such embodiments, the alloy may comprise two of the following metals: copper, nickel, chromium, vanadium, aluminum, silver, iron, palladium, molybdenum, gold and zinc, and any of the foregoing oxide formers. May be substantially absent.

In embodiments wherein the alloy comprises an oxide former, the alloy is at least about 0.5 atomic% oxide former (eg, at least about 1 atomic% oxide former, or at least about 2 atomic% oxide former). And up to about 25 atomic% oxide formers (eg, up to about 10 atomic% oxide formers, or up to about 4 atomic% oxide formers). For example, the alloy may comprise an oxide former (eg, at least about 0.5 aluminum), about 25 atomic% to about 55 atomic% nickel (eg, about 35 atomic% to about 55 atomic% nickel, or about 40 atomic% to about 55 atomic% nickel), the balance being copper. As another example, the alloy may comprise an oxide former (eg, at least about 0.5 atomic% aluminum), about 5 atomic% to about 20 atomic% chromium (eg, about 10 atomic% to about 18 atomic% chromium). Or from about 10 atomic% to about 15 atomic% chromium), with the balance being nickel. The alloy may comprise a relatively small amount of additional metal (eg, less than about 0.1 atomic percent additional metal, less than about 0.01 atomic percent additional metal, or less than about 0.005 atomic percent additional metal).

Substrates formed of alloys can be produced, for example, by combining, melting and cooling the components in powder form, or by diffusing together the powdered components in the solid state. The alloy is then subjected to deformation texture (eg, annealing and rolling, swaging, extrusion, and / or stretching) to form texture texture surfaces (eg, biaxial texture or square texture). It can be formed by. Alternatively, the alloy constituents can be stacked in the form of jelly rolls and then deformed texture. In some embodiments, materials having a relatively low coefficient of thermal expansion (eg, Nb, Mo, Ta, V, Cr, Zr, Pd, Sb, NbTi, intermetallic materials, such as NiAl or Ni ₃ Al, Or the compound) may be formed into rods and embedded into an alloy and then deformed texture.

In some embodiments, stable oxide formation at the surface is alleviated until a first epitaxial (eg, buffer) layer is formed on the biaxial textured alloy surface using an intermediate layer disposed on the surface of the substrate. Can be. The intermediate layer comprises an epitaxial metal or alloy layer that does not form a surface oxide when exposed to the conditions required by the temperature and PO ₂ required for the initial growth of the epitaxial buffer layer film. The buffer layer also acts as a barrier to prevent substrate element (s) from moving to the surface of the intermediate layer and forming oxides during the initial growth of the epitaxial layer. In the absence of such an intermediate layer, one or more elements of the substrate are expected to form thermodynamically stable oxide (s) at the substrate surface, which oxide may, for example, be formed of the epitaxial layer due to lack of texture in the oxide layer. Can significantly interfere with deposition.

In some such embodiments, the intermediate layer is virtual in nature. As used herein, “temporary” refers to an intermediate layer incorporated into or present with a biaxial aggregated substrate wholly or partially after initial nucleation and growth of the epitaxial film. Even under these circumstances, the intermediate layer and the biaxial textured substrate remain separate until the epitaxial properties of the deposited film are established. The use of a temporary intermediate layer may be desirable when the intermediate layer has some undesirable properties, for example when the intermediate layer is magnetic, eg nickel.

Exemplary metal intermediate layers include nickel, gold, silver, palladium and alloys thereof. Additional metals or alloys may include alloys of nickel and / or copper. The epitaxial film or layer deposited on the intermediate layer may include metal oxides, chalcogenides, halides, and nitrides. In some embodiments, the metal intermediate layer is not oxidized under epitaxial film deposition conditions.

Care must be taken to ensure that the deposition intermediate layer does not fully mix into or diffuse into the substrate before the epitaxial layer is established by nucleation and growth of the initial buffer layer structure. It selects the metal (or alloy) for suitable properties such as diffusion constant in the substrate alloy, thermodynamic stability against oxidation under actual epitaxial buffer layer growth conditions, and lattice matching with the epitaxial layer, and then epitaxially deposits the thickness of the deposited metal layer. This means that it must be modified according to the conditions for the deposition of the layer, especially the temperature.

Deposition of the metal intermediate layer can be carried out in a vacuum process such as evaporation or sputtering, or by electrochemical means, for example electroplating (with or without electrode). This deposited metal intermediate layer may or may not be epitaxial after deposition (depending on the temperature of the substrate during deposition), but then epitaxial orientation may be obtained during post-deposition heat treatment.

In certain embodiments, sulfur may be formed on the surface of the intermediate layer. Sulfur, for example, comprises an intermediate layer comprising a sulfur source (eg H ₂ S, tantalum foil or silver foil) and hydrogen (eg hydrogen, or a mixture of hydrogen and an inert gas, eg 5% hydrogen / Formed on the surface of the intermediate layer by exposure to a gaseous environment comprising an argon gas mixture for a period of time (e.g., from about 10 seconds to about 1 hour, about 1 minute to about 30 minutes, about 5 minutes to about 15 minutes) You can. This can be done at elevated temperatures (eg, temperatures of about 450 ° C. to about 1100 ° C., about 600 ° C. to about 900 ° C., 850 ° C.). The pressure of hydrogen (or hydrogen / inert gas mixture) may be relatively low (eg, less than about 1 torr, less than about 1x10 ^-3 torr, less than about 1x10 ^-6 torr) or relatively high (eg , Greater than about 1 torr, greater than about 100 torr, greater than about 760 torr).

While not wishing to be bound by theory, exposing the textured substrate surface to a sulfur source under the above conditions results in the formation of a sulfur superstructure (eg, c (2X2) superstructure) on the textured substrate surface. It is believed that it can be formed. It is also contemplated that this superstructure may be effective for stabilizing (eg, chemical and / or physical stabilization) of the surface of the intermediate layer.

While one approach has been described for forming sulfur superstructures, other methods of forming such superstructures may also be used. For example, sulfur superstructures (eg, S c (2 × 2)) can be formed by applying a suitable organic solution to the surface of the intermediate layer by heating to a suitable temperature in a suitable gaseous environment.

In addition, although the formation of sulfur superstructures on the surface of the intermediate layer has been described, it is contemplated that other superstructures may also be effective for stabilizing the surface (eg, chemical and / or physical stabilization). For example, it is contemplated that oxygen superstructures, nitrogen superstructures, carbon superstructures, potassium superstructures, cesium superstructures, lithium superstructures, or selenium superstructures disposed on the surface may be effective in enhancing the stability of the surface.

In the second processing station 420, a buffer layer is formed on the textured substrate. The buffer layer may be formed using ion beam assisted deposition (IBAD). In this technique, the buffer layer material is for example an electron beam evaporation method, a sputtering deposition method, or a pulsed type while directing an ion beam (eg an argon ion beam) to a smooth amorphous surface of the substrate on which the evaporation buffer layer material is deposited. Evaporate using a laser deposition method.

For example, the buffer layer may be a buffer layer material (eg, a material having a rock salt structure) having a rock salt like structure onto a smooth amorphous surface of the substrate (eg, a surface having a root mean square roughness of less than about 100 angstroms). Oxides, including MgO, or nitrides) to be formed by ion beam assisted deposition to ensure that the buffer layer material has a surface with significant alignment (eg, about 13 ⁰ or less), both in and out of plane. Can be.

Conditions used during the deposition of the buffer layer material may be, for example, substrate temperatures of about 0 ° C. to about 750 ° C. (eg, about 0 ° C. to about 400 ° C., about room temperature to about 75 ° C., about room temperature to about 400 ° C.). A deposition rate of about 1.0 angstroms per second to about 4.4 angstroms per second, ion energy of about 200 eV to about 1200 eV, and / or about 110 microamps per square centimeter to about 120 microamps per square centimeter. Ionic flow rates.

In some embodiments, when using IBAD, the substrate is a material having a polycrystalline non-amorphous base structure (eg, a metal alloy) having a smooth amorphous surface formed from a different material (eg, Si ₃ N ₄ ). , For example, nickel alloys).

In certain embodiments, a plurality of buffer layers may be deposited by epitaxial growth on the original IBAD surface. Each buffer layer may have significant alignment (eg, about 13 ⁰ or less) in both in-plane and out-of-plane.

The buffer is a solution phase technique comprising metal organic deposition, for example, S. S. Shoup et al., J. Am. Cer. Soc, vol. 81, 3019; D. Beach et al. Res. Soc. Symp. Proc, vol. 495, 263 (1988); M. Paranthaman et al., Superconductor Sci. Tech., Vol. 12, 319 (1999); DJ. Lee et al., Japanese J. Appl. Phys., Vol. 38, L178 (1999) and in M.W. Rupich et al., I.E.E.E. Trans, on Appl. Supercon. vol. 9, 1527] can be manufactured using. In certain embodiments, a solution coating process may be used to deposit one or a combination of any of the oxide layers on the textured substrate, although the process may be performed on seeded metal substrates (seed). May be particularly applicable to the deposition of layers. The role of the seed layer is to: 1) remove the substrate from oxidation during deposition of the next oxide layer (e.g., magnetron sputter deposition of yttria-stabilized zirconia from an oxide target) when carried out in an oxidizing environment with respect to the substrate. To protect; And 2) providing an epitaxial template for subsequent growth of the oxide layer. To meet this requirement, the seed layer should be free of any contaminants that may grow epitaxially over the entire surface of the metal substrate and may interfere with subsequent deposition of the epitaxial oxide layer.

Formation of the oxide buffer layer may be carried out to promote wetting of the underlying substrate layer. Additionally, in certain embodiments, the formation of the metal oxide layer can be carried out using a metal alkoxide precursor (eg, a "sol gel" precursor).

Once the textured substrate comprising the buffer layer is prepared, the precursor solution is deposited at station 430 as described above. As indicated above, one or more layers are deposited to form a precursor layer having the desired thickness and overall composition.

In a subsequent station 440, the precursor component is decomposed. The conversion of the precursor component to the oxide superconductor is carried out as previously reported for continuous precursor thick films. In the case of precursor components comprising at least one fluoride containing salt, the first step of the heating step is performed to decompose the metal organic molecules into one or more oxyfluoride intermediates of the desired superconductor material.

Typically, the initial temperature at this stage is approximately room temperature and the final temperature is from about 190 ° C to about 210 ° C, preferably up to about 200 ° C. Preferably, this step uses a temperature ramp of at least about 5 ° C. per minute, more preferably a temperature ramp of at least about 10 ° C. per minute, most preferably a temperature ramp of at least about 15 ° C. per minute. To perform. During this step, the partial pressure of water vapor in the nominal gaseous environment is preferably maintained at about 5 Torr to about 50 Torr, more preferably about 5 Torr to about 30 Torr, most preferably about 20 Torr to about 30 Torr. do. The partial pressure of oxygen in the nominal gaseous environment is maintained at about 0.1 Torr to about 760 Torr, preferably about 730-740 Torr.

The heating is then performed at a temperature of about 200 ° C. to about 290 ° C. using a temperature ramp of about 0.05 ° C. per minute to about 5 ° C. per minute (eg, about 0.5 ° C. per minute to about 1 ° C. per minute). Continue to Preferably, the gaseous environment during this heating is substantially the same as the nominal gaseous environment used when heating the sample from the initial temperature to about 190 ° C to about 215 ° C.

Heating is further continued to a temperature of about 650 ° C., or more preferably to a temperature of about 400 ° C. to form the oxyfluoride intermediate. This step is preferably carried out using a temperature ramp of at least about 2 ° C. per minute, more preferably at least about 3 ° C. per minute, most preferably at least about 5 ° C. per minute. Preferably, the gaseous environment during this heating step is substantially the same as the nominal gaseous environment used when heating the sample from the initial temperature to about 190 ° C to about 215 ° C.

In an alternative embodiment, the barium fluoride is used to convert the dried solution to about 5 Torr to about 50 Torr of water vapor (e.g., about 5 Torr to about 30 Torr of water vapor, or about 10 Torr to about 25 Torr of water vapor. It is formed by heating from an initial temperature (eg room temperature) to about 19O < 0 > The nominal partial pressure of oxygen can be, for example, about 0.1 Torr to about 760 Torr. In this embodiment, the heating is then performed at a water vapor pressure of about 5 Torr to about 50 Torr (e.g., about 5 Torr to about 30 Torr, or about 10 Torr to about 25 Torr). Continue to a temperature of from about < RTI ID = 0.0 > The nominal partial pressure of oxygen can be, for example, about 0.1 Torr to about 760 Torr. This is followed by at least about 2 ° C. per minute at a water vapor pressure of about 5 Torr to about 50 Torr (eg about 5 Torr to about 30 Torr, or about 10 Torr to about 25 Torr). , At least about 3 ° C. per minute, or at least about 5 ° C. per minute) to about 400 ° C. to form barium fluoride. The nominal partial pressure of oxygen can be, for example, about 0.1 Torr to about 760 Torr.

In certain embodiments, heating the dried solution to form barium fluoride (eg, at least about 100 ° C., at least about 150 ° C., at least about 200 ° C., at most about 300 ° C., at most about 250 ° C., about 200 Placing the coated sample in a preheated furnace). The gaseous environment in the furnace is for example a total gas pressure of about 760 Torr, a predetermined partial pressure of water vapor (e.g., at least about 10 Torr, at least about 15 Torr, up to about 25 Torr, up to about 20 Torr, about 17 Torr) And the remaining torr is an oxygen molecule. After the coated sample reaches the temperature of the furnace, the temperature of the furnace is determined by a predetermined temperature ramp rate (eg, at least about 0.5 ° C. per minute, at least about O.75 ° C. per minute, up to about 2 ° C. per minute, Up to about 1.5 ° C. per minute, about 1 ° C. per minute) (eg, at least about 225 ° C., at least about 24 ° C., up to about 275 ° C., up to about 260 ° C., about 250 Up to ℃). This step can be performed using the same nominal gaseous environment used in the first heating step. The temperature of the furnace is then determined by a predetermined temperature ramp rate (eg, at least about 5 ° C. per minute, at least about 8 ° C. per minute, up to about 20 ° C. per minute, up to about 12 ° C. per minute, about per minute). 10 ° C.) (eg, up to at least about 350 ° C., up to at least about 375 ° C., up to about 45 ° C., up to about 425 ° C., up to about 45 ° C.). This step can be performed using the same nominal gaseous environment used in the first heating step.

The treatment of the metal salt solution can produce an oxyfluoride intermediate film in which the constituent metal oxide and the metal fluoride are homogeneously distributed throughout the film. Preferably, this precursor has a relatively low defect density and is essentially free of cracks through the intermediate thickness. While solution chemical properties for barium fluoride formation are disclosed, other methods may be used for other precursor solutions.

The superconductor intermediate film may then be heated to form the desired superconductor layer in further processing station 450. Typically this step is from about room temperature with a temperature ramp of greater than about 25 ° C. per minute, preferably at a temperature rate of greater than about 100 ° C. per minute, more preferably at a temperature rate of greater than about 200 ° C. per minute. By heating to a temperature of about 700 ° C. to about 825 ° C., preferably to a temperature of about 74 ° C. to 800 ° C., more preferably to a temperature of about 750 ° C. to about 790 ° C. This step may also start from a final temperature of about 400-65 ° C. used to form the intermediate oxyfluoride membrane. During this step, process gas is flowed over the membrane surface to feed the gaseous reactants to the membrane and remove the gaseous reaction product from the membrane. The nominal gaseous environment during this stage has a total pressure of about 0.1 Torr to about 760 Torr, oxygen of about 0.09 Torr to about 50 Torr and water vapor of about 0.01 Torr to about 150 Torr and inertness of about 0 Torr to about 750 Torr. Consists of gas (nitrogen or argon). More preferably, the nominal gaseous environment has a total pressure of about 0.15 Torr to about 5 Torr and consists of about 0.1 Torr to about 1 Torr of oxygen and about 0.05 Torr to about 4 Torr of water vapor.

The membrane is then at a temperature of about 700 ° C.-825 ° C., preferably at a temperature of about 740 ° C. to 800 ° C., more preferably at a temperature of about 750 ° C. to about 79 ° C., for a time period of at least about 5 minutes to about 120 minutes, Preferably for at least about 15 minutes to about 60 minutes, more preferably for at least about 15 minutes to about 30 minutes. During this step, process gas is flowed over the membrane surface to feed the gaseous reactants to the membrane and remove the gaseous reaction product from the membrane. The nominal gaseous environment during this stage has a total pressure of about 0.1 Torr to about 760 Torr, oxygen of about 0.09 Torr to about 50 Torr and water vapor of about 0.01 Torr to about 150 Torr and inert gas of about 0 Torr to about 750 Torr. (Nitrogen or argon). More preferably, the nominal gaseous environment has a total pressure of about 0.15 Torr to about 5 Torr and consists of about 0.1 Torr to about 1 Torr of oxygen and about 0.05 Torr to about 4 Torr of water vapor.

The membrane is then cooled to room temperature in a nominal gaseous environment with an oxygen pressure of about 0.05 Torr to about 150 Torr, preferably about 0.1 Torr to about 0.5 Torr, more preferably about 0.1 Torr to about 0.2 Torr.

The resulting superconductor layers are well arranged (e.g. biaxially aggregated in plane or on c-axis outside the plane and biaxially aggregated in plane). In embodiments, the bulk of the superconductor material is biaxially textured. The superconductor layer can be at least about 1 micrometer thick (eg, at least about 2 micrometer thick, at least about 3 micrometer thick, at least about 4 micrometer thick, at least about 5 micrometer thick). The oxide superconductor has a substantially constant c-axis orientation across its width and the c-axis orientation of the superconductor is substantially perpendicular to the surface of the wire or tape.

Low ac loss by completing this process by further processing by precious metal deposition at station 460, oxygen annealing at station 470, lamination at station 480, and slitting at station 490. Allows low cost fabrication of coated conductor wires. The invention is described in more detail in the following examples, which are intended to illustrate only, as many variations and modifications will be apparent to those skilled in the art.

Example  One: Y123  Manufacture of membrane

A YBCO precursor solution having a stoichiometric ratio of 1: 2: 3 of Y: Ba: Cu contains about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) ₂ , and about 1.28 grams Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

The precursor solution was fabricated on a 1 cm wide, 1 cm wide (1.5 cm to 2 cm) biaxially textured oxide buffer metal substrate having a structure of Ni (5at%) / W / Y ₂ O ₃ / YSZ / CeO ₂ . It was deposited by spin coating technique at a rate of RPM. Sufficient amount of precursor solution was deposited to yield a YBa ₂ Cu ₃ O _{7 -x} film about 0.8 μm thick.

The coated sample is from room temperature to about 200 ° C. at a rate of about 15 ° C. per minute in a flow gas environment with a total gas pressure of about 760 torr (water vapor pressure of about 24 torr and oxygen of the remaining torr), followed by about 0.9 ° per minute The metal oxyfluoride intermediate membrane was decomposed by heating in a 2.25 "diameter tubular furnace at a rate of about 200 ° C. to about 250 ° C., then about 250 ° C. to about 400 ° C. at a rate of about 5 ° C. per minute.

The metal oxyfluoride film was then heat treated to form an oxide superconductor. A short length (1-2 cm) intermediate membrane is heated in a tubular furnace to about 785 ° C. at a rate of about 200 ° C. per minute and the total gas pressure is about 240 mtorr (water vapor pressure of about 90 mtorr, and about 150 mtorr of oxygen gas). Pressure) for about 30 minutes. After 30 minutes of maintenance, the H ₂ O vapor was removed from the gaseous environment and the membrane was then cooled to room temperature at about 150 mtorr O ₂ . The resulting film was about 0.8 microns thick.

It was then coated with a layer of Ag 2 ㎛ thickness of the sample by thermal evaporation and annealing at 55O ℃ in 100% O ₂ for 30 minutes, then cooled to room temperature.

Example  2: Containing excess Cu Y123  Manufacture of membrane

A YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu of 1: 2: 3.34 contains about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) _2, and about 1.54 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

This precursor was coated, decomposed and processed as described in Example 1. The resulting film was about 0.8 microns thick. This preparation was repeated using various excess Cu concentrations. 5 shows that with increasing Cu concentration, Ic also increases to approximately 20% excess Cu, after which the Ic begins to decrease.

Example  3: Excess Cu And Scarce Ba Containing Y123  Manufacture of membrane

The YBCO precursor solution with a stoichiometric ratio of 1: 1.6: 3.6 of Y: Ba: Cu yields about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.28 grams of Ba (CF ₃ CO ₂ ) ₂ and about 2.3 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

This precursor was coated, decomposed and processed as described in Example 1. The resulting film was about 0.8 microns thick. The critical current of the final film was found to be 219 A / cmW.

Example  4: Stoichiometric Solution layer  Previously containing a Cu layer Y123  Manufacture of membrane

A YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu 1: 2: 3 contains about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) ₂ and about 1.28 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

Cu precursor solutions were prepared by dissolving about 1.54 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

This Cu precursor solution was formed on a biaxial aggregated oxide buffer metal substrate of a predetermined length (1.5 cm to 2 cm) having a structure of Ni (5at%) / W / Y ₂ O ₃ / YSZ / CeO ₂ . Deposited by spin coating technology at a rate of 1000-3000 rpm. Sufficient amount of precursor solution was deposited to obtain a Cu film of sufficient thickness.

The YBCO precursor solution was then deposited onto the Cu film by spin coating technology at a rate of 2000 RPM. Sufficient amount of precursor solution was deposited to yield a YBa ₂ Cu ₃ O _{7 -x} film about 0.8 μm thick.

The coated sample was digested and processed as described in Example 1. The resulting film was about 0.8 microns thick. 6 shows that the critical current of the film at 77 K, in its own field increases with increasing spin rate but decreases when no additional Cu layer is present.

Example  5: Stoichiometric  Solution Double layer  Containing coating Y123  Manufacture of membrane

A YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu 1: 2: 3 contains about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) ₂ and about 1.28 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

This YBCO precursor solution is a slot die on a 1 cm wide, predetermined length (1 meter) biaxial aggregated oxide buffer metal substrate having a structure of Ni (5at%) / W / Y ₂ O ₃ / YSZ / CeO ₂ . It was deposited by a slot die coating technique. Sufficient amount of precursor solution was deposited to yield a YBa ₂ Cu ₃ O _{7 -x} film about 0.8 μm thick. The coated sample was denatured to a reel system by reel with the temperature profile and atmosphere described in Example 1.

The deteriorated tape was cut into two 0.5 m pieces. A second layer of YBCO precursor solution with a stoichiometric ratio of Y: Ba: Cu 1: 2: 3 was deposited on the first 0.5 m decomposition tape by slot die coating technique. Sufficient amount of precursor solution was deposited to produce a 0.6 μm thick YBa ₂ Cu ₃ 0 _7-x film. The coated sample was denatured and processed by the reel to the reel system as above, except that P H _{2 O} during decomposition in the second layer decomposition was 7 torr and the remaining torr was oxygen.

The altered tape was cut into 1 cm x 2 cm pieces and processed in a stationary furnace. The sample was first heated to 58 ° C. in an atmosphere of 150 mtorr O ₂ and 300 mtorr H ₂ O, with an O ₂ flow rate of 11 cc / min and an H ₂ O flow rate adjusted through the leak valve to achieve the desired pH ₂ O. do. The heating rate is about 200 ° C./min. The sample was held for 10 minutes and then H ₂ O was locked. The sample was cooled to room temperature in a dry 150 mtorr O ₂ atmosphere.

The sample was then heated to 785 ° C. at a heating rate of about 200 ° C./min in dry 150 mtorr O ₂ . Once the sample reached a holding temperature of 785 ° C., 200 mtorr of H ₂ O vapor was introduced to convert the precursor to the YBa ₂ Cu ₃ O _x phase. The holding time is about 60 minutes. After 60 minutes of maintenance, H ₂ O was locked off and the sample was cooled to room temperature in 150 mtorr of dry O ₂ .

The sample was then Ag coated and O ₂ annealed as described in Example 1.

The critical current of the final membrane was measured by four probe method at 77 K, in its own field. The measured threshold current is shown in FIG. 7 and is indicated by "baseline" in this figure.

Example  6: using excess Cu solution in the second layer Double layer  Preparation of Y123 Membrane Including Coating

A second YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu of 1: 2: 3.6 contains about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) ₂ and about 1.54 grams Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

A second YBCO precursor solution was deposited by a slot die coating technique on a second piece of 0.5 m long degraded precursor tape mentioned in Example 5. A sufficient amount of precursor solution was deposited to produce a YBa ₂ Cu ₃ O _{7 -x} film about 0.6 μm thick. The coated sample was digested and processed as described in Example 5.

The altered tape was cut into pieces of 1 cm × 2 cm and processed in a stationary furnace. The sample was first heated to 58 ° C. in an atmosphere of 150 mtorr O ₂ and 300 mtorr H ₂ O, with an O ₂ flow rate of 11 cc / min and an H ₂ O flow rate adjusted through the leak valve to achieve the desired pH ₂ O. do. The heating rate is about 200 ° C./min. The sample was held for 10 minutes and then H ₂ O was locked. The sample was cooled to room temperature in a dry 150 mtorr O ₂ atmosphere.

The sample was then heated to 785 ° C. at a heating rate of about 200 ° C./min in dry 150 mtorr O ₂ . Once the sample reached a holding temperature of 785 ° C., 200 mtorr of H ₂ O vapor was introduced to convert the precursor to the YBa ₂ Cu ₃ O _x phase. The holding time is about 60 minutes. After 60 minutes of maintenance, H ₂ O was locked off and the sample was cooled to room temperature in 150 mtorr of dry O ₂ .

The sample was then Ag coated and O ₂ annealed as described in Example 1.

The critical current of the final membrane was measured by means of four probes at 77 K in its own field. The measured threshold current is shown in FIG. 7 and is shown as “Cu + 20%” in this figure.

Example  7: 15 mol% excess Cu and 50% Dy Added Dy - Y123 Superconducting  Produce

The precursor solution is about 0.83 grams of Y (CF ₃ CO ₂ ) ₃ , about 0.336 grams of Dy (CH ₃ CO ₂ ) ₃ , about 1.60 grams of Ba (CF ₃ CO ₂ ) ₂ and about 1.47 grams of Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 ml of methanol (CH ₃ OH) and about 0.15 ml of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 ml with methanol.

The precursors were coated, decomposed, processed and Ag coated as described in Example 1. Coating is carried out at a theoretical Y123 thickness of 0.8 μm. The resulting film has a smooth glossy surface. The final thickness after conversion is 1.1 μm. The x-ray diffraction pattern of the final film showed the presence of (00 L) texture Y (Dy) Ba ₂ Cu ₃ O _7-x with Ic values greater than 360 A / cm-w at 77 K and its own field. .

Example  8: double coating comprising Cu intermediate layer Superconducting  Produce

A baseline YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu of 1: 2: 3.23 contains about 0.85 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.45 grams of Ba (CF ₃ CO ₂ ) _2, and about 1.35 grams Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 mL of methanol (CH ₃ OH) and about 0.15 mL of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 mL with methanol.

A 1.2 M Cu (C ₂ H ₅ CO ₂ ) ₂ solution was prepared by dissolving 1.24 g of Cu (C ₂ H ₅ CO ₂ ) ₂ powder in 4.85 ml of methanol and 0.15 ml of C ₂ H ₅ CO ₂ H. .

The baseline precursor solution was first deposited on a biaxial textured oxide buffer metal substrate having a Ni (5at%) W / Y ₂ O ₃ / YSZ / CeO ₂ structure by slot die coating technique. This solution was coated on the buffered substrate in the desired amount to form a 0.8 μm thick REBa ₂ Cu ₃ 0 _{7 -x} film.

The coated sample is from room temperature to about 200 ° C. at a rate of about 15 ° C. per minute in a flow gas environment with a total gas pressure of about 760 torr (water vapor pressure of about 24 torr and oxygen of the remaining torr), followed by about 0.9 ° per minute The metal oxyfluoride intermediate membrane was decomposed by heating in a 2.25 "diameter tubular furnace at a rate of about 200 ° C. to about 250 ° C., then about 250 ° C. to about 400 ° C. at a rate of about 5 ° C. per minute.

The metal oxyfluoride film was then coated with a Cu (C ₂ H ₅ CO ₂ ) ₂ solution to a target thickness of 0.1 μm. The coated film was dried at 95 ° C. through a heated tunnel. The dried membrane was then recoated with a baseline solution prepared as previously mentioned with a baseline of the target final thickness of 0.6 μm.

By the same process as mentioned previously, the coated tape was again decomposed to form intermediate metal oxyfluoride, but this time the H ₂ O vapor pressure was controlled to about 6.5 torr.

The deteriorated tape was heat treated to form an oxide superconductor. This tape was combined with 4 m of similarly coated NiW leader tape at both front and back to establish a uniform control environment during the reaction. The tape was then reacted at 785 ° C. using the following parameters. The tape was ramped up to 785 ° C. at an average ramp rate of about 520 ° C./min. During the reaction, the total pressure during the reaction was controlled to about 1 torr. The partial pressure of H ₂ O was about 800 mtorr and the partial pressure of oxygen was about 200 mtorr. The reaction time was about 1 minute. A total pressure of about 1 torr was used during cooling, the oxygen partial pressure was about 200 mtorr and the N ₂ partial pressure was about 80 mtorr.

The reacted film was coated with an Ag protective layer of 3 mu m and then annealed in an oxygen environment of 760 torr. The resulting film or Ic is approximately per 1 cm width of about 35OA Jc 2.5MA / cm ² - was - 77K, in self-field.

Example  9: double coated with different composition and Cu intermediate layer Superconducting  Produce

A baseline YBCO precursor solution having a stoichiometric ratio of Y: Ba: Cu of 1: 2: 3.23 contains about 0.85 grams of Y (CF ₃ CO ₂ ) ₃ , about 1.45 grams of Ba (CF ₃ CO ₂ ) _2, and about 1.35 grams Cu (C ₂ H ₅ CO ₂ ) ₂ was prepared by dissolving in about 4.85 mL of methanol (CH ₃ OH) and about 0.15 mL of propionic acid (C ₂ H ₆ CO ₂ ). The final volume of this solution was adjusted to about 5 mL with methanol.

A baseline YBCO precursor solution with 50% dysprosium added and a stoichiometric ratio of Y: Dy: Ba: Cu 1: 0.5: 2: 3.23 yields about 1.70 grams of Dy (CH ₃ CO ₂ ) ₃ , and about 20 mL of baseline Prepared by dissolving about 1.90 mL of methanol (CH ₃ OH) in the sun solution. The final volume of this solution was adjusted to about 25 mL with that of the baseline solution.

A 1.2 M Cu (C ₂ H ₅ CO ₂ ) ₂ solution was prepared by dissolving 1.24 g of Cu (C ₂ H ₅ CO ₂ ) ₂ powder in 4.85 ml of methanol and 0.15 ml of C ₂ H ₅ CO ₂ H. .

A precursor solution with 50% Dy added was deposited on a biaxial textured oxide buffer metal substrate having a Ni (5at%) W / Y ₂ O ₃ / YSZ / CeO ₂ structure by slot die coating technique. This solution was coated onto the buffer substrate in the desired amount to form a 0.8 μm thick REBa ₂ Cu ₃ 0 _{7 -x} film.

The coated sample is from room temperature to about 200 ° C. at a rate of about 15 ° C. per minute in a flow gas environment with a total gas pressure of about 760 torr (water vapor pressure of about 24 torr and oxygen of the remaining torr), followed by about 0.9 ° per minute The metal oxyfluoride intermediate membrane was decomposed by heating in a 2.25 "diameter tubular furnace at a rate of about 200 ° C. to about 250 ° C., then about 250 ° C. to about 400 ° C. at a rate of about 5 ° C. per minute.

The metal oxyfluoride film was then coated with a Cu (C ₂ H ₅ CO ₂ ) ₂ solution to a target thickness of 0.1 μm. The coated film was dried at 95 ° C. through a heated tunnel. The dried film was then recoated with a baseline solution prepared as mentioned previously with YBa ₂ CuOx at a target final thickness of 0.6 μm.

By the same process as mentioned previously, the coated tape was again decomposed to form intermediate metal oxyfluoride, but this time the H ₂ O vapor pressure was controlled to about 6.5 torr.

The deteriorated tape was heat treated to form an oxide superconductor. This tape was combined with 4 m of similarly coated NiW leader tape at both front and back to establish a uniform control environment during the reaction. The tape was then reacted at 785 ° C. using the following parameters. The tape was ramped up to 785 ° C with an average ramp rate of about 520 ° C / min. During the reaction, the total pressure during the reaction was controlled to about 1 torr. The partial pressure of H ₂ O was about 800 mtorr and the partial pressure of oxygen was about 200 mtorr. The reaction time was about 11 minutes. A total pressure of about 1 torr was used during cooling, the oxygen partial pressure was about 200 mtorr and the N ₂ partial pressure was about 80 mtorr.

)이 도 8에 도시되어 있다. 77 K 및 1 테슬라에서, HTS 와이어는, 각각 샘플 표면에 대하여 평행하거나 수직인 장에서 전체 Ic가 1 cm 폭 당 78 A 및 113 A이다.The reacted film was coated with an Ag protective layer of 3 mu m and then annealed in an oxygen environment of 760 torr. The resulting film or Ic is approximately per 1 cm width of about 35OA Jc 2.5MA / cm ² - was - 77K, in self-field. Critical Current (Ic) vs. Magnetic Field Orientation at 77 K and 1 Tesla (

) Is shown in FIG. 8. At 77 K and 1 Tesla, the HTS wires are 78 A and 113 A per cm width with an overall I c in a field parallel or perpendicular to the sample surface, respectively.

Cited References

The following documents are incorporated herein by reference: US Pat. No. 5,231,074, issued Feb. 27, 1993, entitled “Preparation of Highly Textured Oxide Superconducting Films from MOD Precursor Solutions”, Feb. 8, 2000 US Patent No. 6,022,832, entitled "Low Vacuum Process for Producing Superconductor Articles with Epitaxial Layers," issued February 22, 2000, and entitled "Low Vacuum Process for Producing Epitaxial Layers" Patent No. 6,027,564, issued Feb. 20, 2001, and entitled “Thin Films Having Rock-Salt-Like Structure Deposited on Amorphous Surfaces” US Patent No. 6,190,752, published on October 5, 2000 International Patent Publication No. WO 00/58530 entitled "Alloy Materials", published October 5, 2000, and International Patent Publication No. WO / 58044 entitled "Alloy Materials", April 1999 8 Published on a date WO 99/17307, entitled "Substrates with Improved Oxidation Resistance," published on April 8, 1999 and entitled WO 99/16941, entitled "Substrates for Superconductors," WO 98/58415, published on Dec. 23, 1998, entitled "Controlled Conversion of Metal Oxyfluorides into Superconducting Oxides," published on Feb. 15, 2001, and entitled "Multi- Layer Articles and Methods of Making Same "WO 01/11428, published on February 1, 2001 and entitled" Multi-Layer Articles And Methods Of Making Same "WO 01 / 08232, published on February 1, 2001 and entitled "Methods And Compositions For Making A Multi-Layer Article" WO 01/08235, published on February 1, 2001, International Patent Publication WO 01 / entitled "Coated Conductor Thick Film Precursor" 08236, published February 1, 2001 and entitled "Coated Conductors With Reduced A.C. Loss "WO 01/08169, published March 1, 2001 and entitled" Surface Control Alloy Substrates And Methods Of Manufacture Therefor "WO 01/15245, 2001 WO 01/08170, published on February 1 and entitled "Enhanced Purity Oxide Layer Formation," published on April 12, 2001, and entitled "Control of Oxide Layer Reaction Rates." International Patent Publication No. WO 01/26164, published on April 12, 2001 and entitled "Oxide Layer Method" International Patent Publication No. WO 01/26165, published on February 1, 2001 WO 01/08233, entitled "Enhanced High Temperature Coated Superconductors," published on February 1, 2001, and entitled "Methods of Making A Superconductor" WO 01/08231 Issue, published April 20, 2002 and entitled "Precursor Solutions and Methods of U" sing Same "WO 02/35615, filed May 26, 2000, and US Patent No. 6,436,317, entitled" Oxide Bronze Compositions And Textured Articles Manufactured In Accordance Therewith ", July 2001 US Provisional Application No. 60 / 309,116, filed 31 March and entitled "Multi-Layer Superconductors And Methods Of Making Same," US Application, filed July 30, 2002, entitled "Superconductor Methods and Reactor" Patent Application No. 10 / 208,134, filed Jul. 31, 2001 and filed with the provisional application "Superconductor Methods and Reactors" US Provisional Application No. 60 / 308,957, filed Nov. 18, 1999, entitled " United States Provisional Application No. 60 / 166,297, filed July 14, 2000, entitled "Superconductor Articles and Compositions and Methods for Making Same" and co-owned US patent application entitled "Superconductor Articles and Compositions and Methods for Making Same" Article 09 / 615,999, both of which are incorporated herein by reference.

Claims (56)

As a method for producing a superconductor oxide film, A first precursor solution comprising precursor components for rare earth-alkaline earth metal-transition metal oxides comprising salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in one or more solvents is deposited on a substrate to form a precursor film Wherein at least one of the salts is a fluoride containing salt and the ratio of transition metal to alkaline earth metal is greater than 1.5; And Treating the precursor film to form a rare earth-alkaline earth-transition metal oxide superconductor, wherein the total ratio of transition metal to alkaline earth metal in the precursor film is greater than 1.5 and the total thickness of the oxide superconductor is greater than about 0.8 μm.  How to include. The method of claim 1, wherein the treating the precursor film is Treating the precursor film to form a metal oxyfluoride intermediate film comprising rare earth, alkaline earth metal and transition metal of the first precursor solution; And Heating the metal oxyfluoride intermediate film to form a rare earth-alkaline earth metal-transition metal oxide superconductor Method comprising a. The method of claim 2, wherein the metal oxyfluoride film comprises yttrium, barium, and copper, and the barium: copper ratio of the film adjacent the substrate / metal oxyfluoride interface is about 2: 3. The method of claim 1 wherein the ratio of transition metal to alkaline earth metal is greater than about 1.6. The method of claim 1 wherein the ratio of transition metal to alkaline earth metal is in the range of greater than about 1.5 to about 1.8. The method of claim 1, wherein the transition metal comprises copper and the alkaline earth metal comprises barium. The method of claim 6, wherein the first precursor solution comprises at least about 5 mol% excess copper. The method of claim 6, wherein the first precursor solution comprises at least about 20 mole% excess copper. The method of claim 6, wherein the first precursor solution is at least 5 mole% deficient in barium. The method of claim 6, wherein the first precursor solution is at least 20 mole% deficient in barium. The method of claim 1, wherein the first precursor solution is deposited to a thickness greater than about 1.0 μm. The method of claim 1 wherein the total thickness of the oxide superconductor is greater than about 1.0 μm. The method of claim 1, wherein the first precursor solution is deposited in two or more deposition steps. The method of claim 1, wherein the depositing the precursor film is Depositing a second precursor solution comprising precursor components for a rare earth-alkaline earth metal-transition metal oxide comprising salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in at least one solvent, wherein the salts At least one of is a fluoride containing salt, the ratio of transition metal to alkaline earth metal is at least 1.5, and the second precursor composition is different from the first precursor composition Further comprising. The method of claim 14, wherein the second precursor solution further comprises one or more additive components or dopant components selected for formation of flux pinning sites in the superconducting film. The method of claim 15, wherein the additive component comprises a soluble component that forms second phase nanoparticles under the conditions used to treat the precursor film. The method of claim 16 wherein the soluble component is selected from the group consisting of compounds of rare earths, alkaline earth metals, transition metals, cerium, zirconium, silver, aluminum and magnesium. The method of claim 15, wherein the dopant component comprises a metal that partially replaces the rare earth, alkaline earth metal, or transition metal of the oxide superconductor. The method of claim 14, wherein the second precursor solution is deposited prior to the deposition of the first precursor solution. The method of claim 14, wherein the second precursor solution is deposited after the first precursor solution. The method of claim 14, wherein the second precursor solution is deposited to form an oxide superconductor having a total thickness of less than about 0.8 μm. The method of claim 1, The substrate is biaxially oriented, The oxide superconductor is biaxially oriented and has a substantially constant c-axis orientation across its width, wherein the c-axis orientation of the oxide superconductor is substantially perpendicular to the surface of the substrate. The method of claim 1, wherein the first precursor solution further comprises one or more additive components or dopant components selected for formation of the flux line anchor point in the superconducting film. The method of claim 23, wherein the additive component comprises a soluble component that forms second phase nanoparticles under the conditions used to treat the precursor film. The method of claim 24, wherein the soluble component is selected from the group consisting of compounds of rare earths, alkaline earth metals, transition metals, cerium, zirconium, silver, aluminum and magnesium. The method of claim 24, wherein the dopant component comprises a metal that partially replaces the rare earth, alkaline earth metal or transition metal of the oxide superconductor. As a method for producing a superconductor membrane, (i) a rare earth-alkaline earth metal-transition metal oxide comprising a first precursor solution consisting predominantly of salts of transition metals in one or more solvents, and salts of rare earth elements, salts of alkaline earth metals, and salts of transition metals in one or more solvents A second precursor solution comprising precursor components for a substrate, wherein at least one of said salts is a fluoride containing salt and wherein the ratio of transition metal to alkaline earth metal is at least 1.5; Disposed in to form a precursor film; And (ii) treating the precursor film to form a rare earth-alkaline earth-transition metal oxide superconductor, wherein the total ratio of transition metal to alkaline earth metal in the precursor film is greater than 1.5 and the total thickness of the oxide superconductor is greater than 0.8 μm. Stage How to include. The method of claim 27, wherein the treating the precursor film is Treating the precursor film to form an intermediate film comprising rare earth, alkaline earth metal, and transition metal of the first and second precursor solutions; And Heating the intermediate film to form a rare earth-alkaline earth-transition metal oxide superconductor How to include. The method of claim 28, wherein the precursor film is heated after deposition of each precursor solution to form an intermediate film comprising the metal components of the precursor solution. The method of claim 27, wherein the total ratio of transition metals to alkaline earth metals is greater than about 1.6. The method of claim 27, wherein the total ratio of transition metal to alkaline earth metal is in the range of greater than about 1.5 to about 1.8. The method of claim 27, wherein the first precursor solution is predominantly composed of copper. The method of claim 27, wherein the first precursor solution is deposited before the second precursor. The method of claim 27, wherein the ratio of copper to barium in the second precursor solution is about 1.5. 35. The method of claim 34, wherein the second precursor further comprises at least one of an additive component and a dopant component selected for formation of a pinning center. The method of claim 27, wherein the ratio of copper to barium in the second precursor solution is greater than 1.5. The method of claim 36, wherein the second precursor further comprises at least one of an additive component and a dopant component selected for formation of a fixed center point. The method of claim 27, wherein the total thickness of the superconducting film is greater than about 1.0 μm. The method of claim 27, Disposing a copper solution on the substrate to form a copper precursor layer; And Disposing a second precursor solution comprising salts of yttrium, barium and copper on the copper precursor layer, wherein the ratio of copper to barium is at least 1.5. How to include. The method of claim 27, The substrate is biaxially oriented, The oxide superconductor is biaxially oriented and has a substantially constant c-axis orientation across its width, wherein the c-axis orientation of the oxide superconductor is substantially perpendicular to the surface of the substrate. An article comprising a biaxially textured substrate having a superconducting layer thereon, The superconducting layer comprises a rare earth barium copper oxide superconductor, The thickness of the superconducting layer is greater than 0.8 μm, The ratio of Cu to Ba of the superconducting layer is greater than 1.5, Wherein said superconducting layer comprises fluoride. The substrate of claim 41, wherein the substrate comprises a material selected from the group consisting of cerium oxide, lanthanum aluminum oxide, lanthanum manganese oxide, strontium titanium oxide, magnesium oxide, neodymium gadolinium oxide, and cerium oxide / yttria-stabilized zirconia. An article comprising a buffer layer. 42. The article of claim 41, wherein the ratio of copper to barium is greater than about 1.6. The article of claim 41, wherein the oxide superconductor has a thickness greater than about 1.0 μm. 42. The article of claim 41, wherein the critical current density of the superconducting layer is at least 200 Amps / cmW at a temperature of 77 K. An oxyfluoride film on a substrate comprising at least one rare earth element, at least one alkaline earth metal and at least one transition metal, Wherein the thickness of the film is greater than 0.8 μm, the ratio of transition metal to alkaline earth metal is greater than 1.5, and the barium: copper ratio of the film adjacent the substrate / metal oxyfluoride interface is about 2: 3. 47. The substrate of claim 46, wherein the substrate comprises a material selected from the group consisting of cerium oxide, lanthanum aluminum oxide, lanthanum manganese oxide, strontium titanium oxide, magnesium oxide, neodymium gadolinium oxide, and cerium oxide / yttria-stabilized zirconia. A metal oxyfluoride membrane comprising a buffer layer. 47. The metal oxyfluoride film of claim 46 wherein the ratio of copper to barium is greater than 1.6. 47. The metal oxyfluoride membrane of claim 46, wherein the thickness of the membrane is greater than 1.0 [mu] m. Adjusting the ratio of transition metal to alkaline earth metal in the precursor solution, wherein the ratio of transition metal to alkaline earth metal is greater than 1.5; Depositing a precursor solution onto the substrate to form a precursor film; And Decomposing the precursor film to achieve a ratio of about 1.5 transition metal to alkaline earth metal adjacent the interface of the precursor film and the substrate. An oxide superconductor manufactured by a method comprising: Wherein the total ratio of transition metals to alkaline earth metals in the oxide superconductor is greater than 1.5 and the total thickness of the oxide superconductor is greater than 0.8 μm. 51. The oxide superconductor of claim 50, wherein adjusting the ratio of transition metal to alkaline earth metal comprises increasing the content of transition metal in the precursor solution. 51. The oxide superconductor of claim 50, wherein the content of transition metal in the precursor solution is increased by at least 5%. 51. The oxide superconductor of claim 50 wherein the content of transition metal in the precursor solution is increased by at least 20%. 51. The oxide superconductor of claim 50, wherein adjusting the ratio of transition metal to alkaline earth metal comprises reducing the content of alkaline earth metal in the precursor solution. 55. The oxide superconductor of claim 54 wherein the amount of alkaline earth metal in the precursor solution is reduced by at least 5%. The oxide superconductor of claim 54, wherein the content of alkaline earth metal in the precursor solution is reduced by at least 50%.

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