Superconducting tape with alloy layer

Abstract

There is presented a method for producing a superconducting tape( 2200), said method comprising providing a substrate (2230), providing a plurality of superconducting elements (2238) on the substrate, each of said superconducting elements being an elongated superconducting element, said plurality of superconducting elements being arranged to be substantially parallel, providing an intermediate layer (2244), said intermediate layer comprising, a metal, and said intermediate layer being arranged at least partially on the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element, providing an opposite layer (2256) adjoining the intermediate layer on the opposite side of the intermediate layer with respect to the superconducting elements, said opposite layer comprising a metal, wherein a metallic composition of the opposite layer is different with respect to a metallic composition of the intermediate layer, and forming an alloy layer (2258) by alloying the intermediate layer and the opposite layer at their interface. There is furthermore presented a superconducting tape (2200) and use thereof for carrying an electrical current.

Description

[0001] SUPERCONDUCTING TAPE WITH ALLOY LAYER

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a superconductor, and more particularly relates to a method for producing a superconducting tape with an alloy layer, and furthermore relates to a superconducting tape with an alloy layer.

[0004] BACKGROUND OF THE INVENTION

[0005] Superconducting tapes may be seen as advantageous since they enable conducting current, such as direct current, without resistive electrical losses. Superconducting tapes are thus being used for several applications, such as power cables, electromagnets, generators and transformers. However, a superconducting tape may exhibit high energy losses when used in alternating current (AC) applications. Furthermore, a superconducting tape may exhibit local heating, e.g., due to resistive heating upon a current being led through non-superconducting parts of the superconducting tape.

[0006] An improved method for providing a superconducting tape would be desirable, such as a method for providing a superconducting tape, which enables reducing, minimizing, or eliminating losses when used in alternating current (AC) applications, which enables reducing, minimizing, or eliminating an effect from magnetic fields or renders the effect less undesirable, and / or which enables reducing, minimizing, or eliminating a risk of local overheating (which may in turn enable reducing, minimizing, or eliminating a risk of serious damage, e.g ., in case of defects) in the superconducting tape.

[0007] Kurihara et aL, PHYSICA C, vol. 530, 10 August 2016, pages 68-71, describes Multi- filamentary REBCO tapes fabricated by scratching a buffer layer along the tape longitudinal direction.

[0008] WO 2020 / 212194 Al describes a sealed superconductor tape.

[0009] US 6 469 253 81 Bl describes an oxide superconducting wire with stabilizing metal have none noble component. SUMMARY OF THE INVENTION

[0010] It may be seen as an object of the present invention to provide an improved superconducting tape, which enables reducing, minimizing, or eliminating losses when used in alternating current (AC) applications, which enables reducing, minimizing, or eliminating an effect from magnetic fields or renders the effect less undesirable, and / or which enables reducing, minimizing, or eliminating a risk of serious damage in case of defects in one or more filaments in the tape. It is a further object of the present invention to provide an alternative to the prior art.

[0011] Thus, the above-described object and several other objects are intended to be obtained in a first aspect of the invention by providing a method for producing a superconducting tape, said method comprising, optionally sequentially: a. Providing a substrate, b. Providing a plurality of superconducting elements on the substrate, each of said superconducting elements being an elongated superconducting element, each of said superconducting elements optionally being on the same side of the substrate, and said plurality of superconducting elements being arranged to be substantially parallel, such as parallel, c. Providing an intermediate layer, said intermediate layer comprising, such as consisting of, a metal, and said intermediate layer being arranged at least partially, such as partially or fully, such as fully, on the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element, d. Providing an opposite layer adjoining the intermediate layer on the opposite side of the intermediate layer with respect to the superconducting elements, said opposite layer optionally comprising, such as consisting of, a metal, wherein a composition of the opposite layer is different with respect to a composition of the intermediate layer, and e. Forming an alloy layer by alloying the intermediate layer and the opposite layer at their interface.

[0012] The invention may be particularly, but not exclusively, advantageous for providing a superconducting tape comprising a plurality of superconducting elements, which enables one or more of the above-mentioned advantages, and / or one or more of reducing, minimizing, or eliminating energy losses when used in alternating current (AC) applications, which enables reducing, minimizing, or eliminating an effect from magnetic fields or renders the effect less undesirable, such as improving magnetic field stabilization, reducing magnetic field related forces, and / or enabling reducing, minimizing, or eliminating a risk of serious damage in case of one or more defects in one or more superconducting elements in the superconducting tape.

[0013] For example, by providing the intermediate layer and the opposite layer and by forming the alloy layer, it is possible to reduce the thickness of the intermediate layer. This may mean that certain parts of the intermediate layer may become thinner, which may in turn mean that an electrical resistance (in a direction from a superconducting element to a neighbouring superconducting element) increases, which may improve the electrical and / or magnetic properties of the superconducting tape, such as the electrical and / or magnetic properties of the superconducting tape during AC operation. Additionally, it is possible that the formation of the alloy layer facilitates heat conduction from a superconducting element to a neighbouring superconducting element, which decrease a risk of damage in case of one or more defects in one or more superconducting elements in the superconducting tape (e.g., because heat provided by resistive heating at the defect(s) can be more efficiently led away from the defect(s)).

[0014] It may be seen as an advantage of the present invention that with the introduction of the opposite layer, the step of forming an alloy layer, and the resulting alloy layer, it may be possible to design or engineer, such as improve the intermediate layer, such as wherein the resulting (remaining) intermediate layer has one or more properties, which is / are superior with respect to the original intermediate layer. For example, it may be desirable to maintain portions of the intermediate layer at the superconducting elements, which have a certain low average resistance, while portions of the intermediate layer between the superconducting elements should preferably have a certain high average resistance (with 'high' being relative to the 'low' mentioned a few lines above). In that case, it may be possible to employ a deposition process wherein the intermediate layer is deposited in a certain manner, e.g., with smaller thickness and / or kinks between the superconducting elements. This certain manner of deposition may then be exploited in a subsequent step of forming an alloy layer, wherein a relatively larger amount of intermediate layer may be converted into alloy layer at the kinks and / or at the thinner portions (wherein, e.g., a certain absolute amount of converted intermediate layer will correspond to a larger relative amount).

[0015] 'Superconducting' is understood as is common in the art, such as describing the capability to be 'superconducting' (e.g., during use), which is understood as is common in the art, such as the capability of an element or a material to conduct electrical current with substantially zero, such as zero, electrical resistance, optionally when cooled below a characteristic transition temperature. 'Superconducting' and 'superconductor' may be referred to interchangeably within the present application. The superconductor (material) may be epitaxially grown superconductor material.

[0016] 'Tape' is understood as is common in the art, such as an element which has thickness (length along a first dimension) which is significantly smaller, such as 10, 100 or 1000 times smaller, than its width (length along a second dimension) and where the width is significantly smaller, such as 10, 100, or 1000 times smaller, than its length (length along a third dimension).

[0017] A length of the tape, such as a maximum dimension in a longitudinal direction of the tape, may be equal to or larger than 1 m, such as equal to or larger than 2 m, such as equal to or larger than 3 m, such as equal to or larger than 5 m, such as equal to or larger than 8 m, such as equal to or larger than 10 m, such as equal to or larger than 100 m, such as equal to or larger than 1 km, such as equal to or larger than 10 km, such as equal to or larger than 100 km, such as equal to or larger than 1000 km.

[0018] The length of the tape may be understood to be measured along a dimension substantially parallel to, such as parallel to a current carrying direction during normal use of the tape and / or a longitudinal direction of the superconducting elements.

[0019] By 'superconducting tape' is understood a tape which is superconducting, such as comprises one or more superconducting elements, which enables the superconducting tape to conduct electrical current with substantially zero, such as zero, electrical resistance, optionally when cooled below a characteristic transition temperature. It is foreseen and encompassed, that the superconducting tape furthermore comprises non-superconducting elements, such as a non-superconducting substrate.

[0020] By 'sequentially' may be understood that a certain order is followed, such as the order in which methods steps are listed.

[0021] By 'substrate' may be understood 'a substrate suitable for supporting a superconducting element' which in turn may be understood as a solid element upon which a superconducting material may be placed, such as deposited, so that the superconducting material may form a superconducting element.

[0022] 'Superconductor material' and 'superconducting material' may be referred to interchangeably within the present application.

[0023] 'Superconducting material' is generally understood to refer to a material, substance or composition that itself is capable of exhibiting, such as exhibits, superconductivity (such as at least below a critical temperature), such as a material, substance or composition having a rare-earth barium copper oxide (REBCO) composition or another high-temperature superconductor material composition. The term 'superconducting material' is generally understood to specifically exclude surrounding structural or functional layers, such as buffer layers, substrates, and / or stabilizers.

[0024] The superconducting material may be a biaxially textured superconductor material, a superconducting material of a coated conductor, an epitaxially grown superconducting material, an anisotropic superconducting material, a second-generation high temperature superconductor material, and / or a rare-earth barium copper oxide (REBCO) superconducting material, such as a REBa2CusO7-x superconducting material, where x =0-0.65, and where RE = Y, Gd, Nd or Eu.

[0025] The superconducting material may be a rare-earth barium copper oxide (REBCO) superconducting material, such as a REBa2CusO7-x superconducting material, where x =0- 0.65, and where RE = Y, Gd, Nd or Eu.

[0026] The substrate may be arranged so that the structure and / or texture of the superconducting material in the superconducting element may be endowed to the superconducting layer via the substrate and / or via another layer on the substrate, such as a buffer layer.

[0027] The substrate may comprise, such as consist of, one or more metallic elements (such as metals, semi-metals, semi-conductors, and / or metalloids) or alloys. The substrate may comprise any material selected from the group comprising : a nickel-based alloy, a copperbased alloy, a chrome-based alloy, iron, aluminium, silicon, titanium, tungsten (also known as wolfram (W)), silver, Hastelloy, such as Hastelloy®, Inconel® and stainless steel. The substrate may comprise, such as consist of, non-metals, such as one or more polymers.

[0028] By 'Hastelloy' and / or 'Hastelloy®' is understood an alloy wherein the predominant alloying ingredient is nickel and wherein other alloying ingredients are added, such as the alloy comprising varying percentages of one or more of, such as all of, the elements: molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminium, carbon, and tungsten. In a particular embodiment, Hastelloy is an alloy which comprises the elements Ni, Cr, Fe, Mo, Co, W, C, such as all of Ni, Cr, Fe, Mo, Co, W, and C. In a more particular embodiment, the alloy also comprises Ni, Cr, Fe, Mo, Co, W, C and one or more of the elements Mn, Si, Cu, Ti, Zr, Al and B. In a more particular embodiment, the alloy is understood to comprise approximately 47 wt. percent Ni, 22 wt. percent Cr, 18 wt. percent Fe, 9 wt. percent Mo, 1.5 wt. percent Co, 0.6 wt. percent W, 0.10 wt. percent C, less than 1 wt. percent Mn, less than 1 wt. percent Si and less than 0.008 wt. percent B. Hastelloy may be referred to as "superalloy" or a "high-performance alloy" within the art. 'Hastelloy' and / or 'Hastelloy®' may be understood to refer to one or both of: an alloy defined (as of July 9 2024) according to any of European Norm (EN) 2.4819 as defined in EN 10088-1 / 2 Deutsches Institut fur Normung (DIN) NiMol6Crl5W, American Iron and Steel Institute (AISI) Alloy C-276, Hastelloy® C-276, or Unified Numbering System (UNS) N10276, and / or an alloy defined (as of July 9 2024) according to any of European Norm (EN) 2.4602 as defined in EN 10088-1 / 2 Deutsches Institut fur Normung (DIN) NiCr21Mol4W, American Iron and Steel Institute (AISI) Alloy 22, Hastelloy® C-22, or Unified Numbering System (UNS) N06022.

[0029] ’Hastelloy’ and / or 'Hastelloy®' may additionally or alternatively be understood to refer to one or more of: an alloy having the chemical composition (minimum wt. %; maximum wt. % in parenthesis following each element if two numbers are given, or maximum wt. % if only one number is given): Ni (51.0; 63.0), Cr (15.0; 16.5), Fe (4.0; 7.0), C (0.01), Mn (1.0), Si (0.08), W (3.0; 4.5),

[0030] V (0.3), P (0.02), S (0.01), Mo (15.0; 17.0), Co (2.5), and / or an alloy having the chemical composition (minimum wt. %; maximum wt. % in parenthesis following each element if two numbers are given, or maximum wt. % if only one number is given): Ni (50.0; 63.0), Cr (20.0; 22.5), Fe (2.0; 6.0), C (0.01), Mn (0.5), Si (0.08), W (2.5; 3,5),

[0031] V (0.35), P (0.025), S (0.01), Mo (12.5; 14.5), Co (2.5).

[0032] By 'predominant alloying ingredient' may be understood that the predominant alloying ingredient is the element or substance with the highest percentage by weight in the alloy, such as wherein the predominant alloying ingredient is more than 50 % w / w in the alloy.

[0033] When referring to a material composition, it may in the context of the present document be understood that "comprise" or "comprises" may generally be understood to refer to a content above noise levels and / or to at least 1 wt. percent, such as at least 10 wt. percent, such as at least 20 wt. percent, such as at least 50 wt. percent, such as at least 75 wt. percent, such as at least 90 wt. percent.

[0034] ’Stainless steel’ is generally known in the art, such as an iron-based alloy with a least 10.5 % w / w Chromium, with or without other alloying elements, and a maximum 1.2 % w / w carbon. By 'iron-based' is to be understood that iron is the predominant alloying ingredient. In particular embodiments, there is provided stainless steel with nickel and / or chromium, such as to provide a stainless steel which is corrosion and / or oxidation resistant, mechanically stable and non-magnetic at the operation temperature of the superconducting layer.

[0035] By 'Inconel' and / or 'Inconel®' may be understood an alloy wherein the predominant alloying ingredient is nickel and wherein other alloying ingredients are added, such as the alloy comprising varying percentages of one or more of, such as all of, the elements: molybdenum, chromium, cobalt, iron, copper, manganese, titanium, aluminium, carbon, niobium, tantalum, silicon, sulphur, phosphorus and boron. In a particular embodiment, Inconel is an alloy which comprises the elements Ni, Cr, Fe, C, Mn, Si, Co, Al, Ti, P, S, and Mo. In a more particular embodiment, the alloy also comprises Nb and / or Ta. In a more particular embodiment, the alloy is understood to comprise approximately 64.5 wt. percent Ni, and 22 wt. percent Cr. Inconel may be referred to as "superalloy" or a "high-performance alloy" within the art.

[0036] By 'Inconel' and / or 'Inconel®' may be understood to refer to one or both of: an alloy defined (as of July 9, 2024) according to any of European Norm (EN) 2.4856 as defined in EN 10088-1 / 2 Deutsches Institut fur Normung (DIN) NiCr22Mo9Nb, American Iron and Steel Institute (AISI) Alloy 625, Inconel® 625, or Unified Numbering System (UNS) N06625, and / or an alloy defined (as of July 9, 2024) according to any of European Norm (EN) 2.4816 as defined in EN 10088-1 / 2 Deutsches Institut fur Normung (DIN) NiCrl5Fe, American Iron and Steel Institute (AISI) Alloy 600, Inconel® 600, or Unified Numbering System (UNS) N06600.

[0037] 'Inconel' and / or 'Inconel®' may additionally or alternatively be understood to refer to one or more of: an alloy having the chemical composition (minimum wt. %; maximum wt. % in parenthesis following each element if two numbers are given, or maximum wt. % if only one number is given): Ni (58.0; 71.0), Cr (21.0; 23.0), Fe (5.0), C (0.03; 0.1), Mn (0.5), Si (0.4), Co (1.0), Al (0.4), Ti (0.4), P (0.01), S (0.01), Mo (8.0; 10.0), Nb + Ta (3.2; 3.8), and / or an alloy having the chemical composition (minimum wt. %; maximum wt. % in parenthesis following each element if two numbers are given, or maximum wt. % if only one number is given): Ni (67.2; 80.0) (where the numbers for Ni are given by calculating the remaining wt. % after summing respectively minimum and maximum values for all other mentioned components), Cr (14.0; 17.0), Fe (6.0; 10.0), C (0.05; 0.15), Mn (1.0), Si (0.5), Co (1.5), Co (1.5), Al (0.3), Ti (0.3), P (0.02), S (0.015), Cu (0.5), B (0.006).

[0038] According to an embodiment, the substrate is a roll-processed substrate, such as roll- processed substrate comprising a metal or metal-alloy. An advantage of a roll-processed, such as warm- or cold-roll-processed, metal or metal-alloy may be that it has a high strength, such as a high strength with respect to materials, such as metals or metal-alloys, which are deposited, e.g., via E-beam evaporation, thermal evaporation, sputter deposition or electrochemical deposition. A roll-processed (substrate) material will have a characteristic grain structure, which is visible, e.g., in a scanning electron microscope (SEM). In an embodiment, the substrate is annealed, such as subjected to a heat-treatment, subsequent to being roll-processed. By 'solid element' may be understood an element comprising a solid phase, such as consisting of a solid phase.

[0039] The substrate, and / or the solid element of the substrate, may have any shape, where shape is understood as the geometrical form as seen in a cross-section in a plane being orthogonal to a length axis (such as corresponding to an axis parallel with a direction in which current is to be carried), such as an arbitrary shape, such as any one of a tape-shape, a rectangular shape (such as a quadratic shape), a triangular shape, an ellipsoidal shape (such as a circular shape). The substrate may comprise a substantially planar surface.

[0040] The substrate may be a substrate suitable as a substrate for coated conductors, such as 2ndgeneration High Temperature Superconductor (HTS), such as a rare-earth barium copper oxide (REBCO) superconducting layer, such as a REBa2CusO7-x superconducting layer, where x =0-0.65, and where RE = Y, Gd, Nd or Eu.

[0041] In embodiments, the substrate is a 'tape', i.e., an element which has thickness (length along a first dimension) which is significantly smaller, such as 10, 100 or 1000 times smaller, than its width (length along a second dimension) and where the width is significantly smaller, such as 10, 100, or 1000 times smaller, than its length (length along a third dimension).

[0042] 'Superconducting element(s)' is / are understood as is common in the art, such as each superconducting element being an element capable of conducting electrical current with substantially zero, such as zero, electrical resistance, optionally when cooled below a characteristic transition temperature. It may be understood that each superconducting element comprises, such as consists of, superconducting material.

[0043] A 'superconducting element' may be understood as comprising, such as consisting of, biaxially textured superconductor material, such as wherein adjoining material, if any, optionally having the same biaxial texturing. The superconducting element may in addition to the superconducting material for example furthermore comprise additional (possibly non- superconducting) material, such as one or more buffer layers, optionally wherein the superconducting material and the one or more buffer layers form a coherent structure with matching biaxial texture (i.e., the same biaxial texture of each of the one or more buffer layers and the superconducting material) at the interface. In one example, a superconducting element may comprise, such as consist of, superconductor material and one or more adjacent, such as adjoining, buffer layers. In case of biaxially textured superconducting material where no buffer layer is present and / or adjoining, the superconducting element may in an example comprise, such as consist of, merely the superconducting material. 'Biaxially textured' is to be understood as is common in the art, such as a polycrystalline material, such as a material being characterised by a solid body consisting of multiple individual grains, wherein adjacent grains are separated by grain boundaries to form a single solid element and wherein the grains are substantially being aligned with a specific crystallographic orientation in two on each other perpendicular crystallographic directions. The orientational deviation is within less than 20°, such as the misorientation angle is less than 20°, such as deviating less than 20°, in two on each other perpendicular directions. Biaxial texturing may be achieved via epitaxial coating.

[0044] Additionally, or alternatively, to being biaxially textured, the superconductor material, such as the superconductor material of each filament, may be defined as second-generation (2G) High Temperature Superconductor (HTS).

[0045] Each superconductor filament may comprise, such as consist of, superconducting material of a coated conductor (CC).

[0046] 'Coated conductor' is understood as is common in the art, such as a superconductor, which has been manufactured by coating (superconducting) material on a substrate, such as to form a layer of superconductor material obtaining both in-plane and out-of-plane texturing of the grains (biaxial alignment or biaxial texturing). The biaxial texturing may be seen as achievable via a coated conductor construction and / or via a coated conductor fabrication method.

[0047] The superconductor material, such as the superconductor material of each superconducting element, may be high-temperature superconducting (HTS) material.

[0048] 'High-temperature superconducting (HTS)' (or high-Tc) is understood as is common in the art, such as the capability of a material to be superconducting above a temperature of above 30 Kelvin, such above a temperature corresponding to the boiling point of liquid nitrogen, which is approximately 77 Kelvin.

[0049] A 'buffer (layer)' is understood as is common in the art and may for example be understood to optionally provide structure and / or texture to the superconducting layer and / or may for example be understood to provide an optionally inert chemical barrier.

[0050] By 'a plurality' (such as a plurality of superconducting elements), may be understood a number n (such as a number n of superconducting elements) being equal to or larger than 2, such as larger than 2, such as larger than 3, such as larger than 5, such as larger than 10, such as larger than 20, such as larger than 50, such as larger than 100, such as larger than 200, such as larger than 500, such as larger than 1000.

[0051] By '(providing a plurality of superconducting elements) on the substrate' may be understood that the superconducting elements are rigidly connected to the substrate, optionally directly to the substrate (such as with no other elements in between).

[0052] The wording 'each of said superconducting elements being on the same side of the substrate' is to be understood as is common in the art, such as wherein in at least one cross-sectional plane being orthogonal to the longitudinal direction of the substrate, a rectilinear line can be drawn through a geometrical centre of the substrate and oriented so as to be parallel with a vector between the two points in the substrate being farthest apart with respect to each other, wherein each of the superconducting elements are being partially or fully on the same side of the rectilinear line.

[0053] It is generally understood, however, that superconducting elements being on the same side of the substrate it is not ruled out in the context of the present invention, such as that it is in fact foreseen and encompassed. For example, the embodiments depicted in Figs. 2-21 could be supplemented with embodiments where a similar treatment was carried out on the other side of the substrate, where substrates were joined together upside-down and / or back-to- back.

[0054] By 'elongated' may be understood something having a larger dimension in a first direction (such as the direction referred to as the length direction), such as significantly longer, such as 2, 5, 10, 100, 1000, 10000 or 100000 times longer than the dimension in one or both of the other two directions (such as the directions referred to as width and height) orthogonal to the first direction.

[0055] A possible advantage of the superconducting elements being elongated is that an effective capping or stabilization of each superconducting element becomes possible, such as where the amount of capping, or stabilizing material, such as the fraction of stabilizing material, on the sides of the superconducting element becomes significant or relatively larger (relative to a width of the superconducting elements). By increasing the cross-sectional fraction of stabilizer material relative to the corresponding fraction of superconducting material, a superconducting tape, which has more stabilizing material per area of superconducting material may be provided, and may therefore be more tolerant towards quenching, such as local heating, such as local loss of superconducting properties. Adding stabilizing material (such as a material chosen from the group comprising silver, copper, nickel, tin, aluminium, zinc, niobium, phosphor, sulphur, germanium, chrome, molybdenum and / or bismuth), such as silver, or copper, to the first and second side of the superconducting material may increase thermal and electrical stability of the superconducting material (such as composite). By providing elongated superconducting elements, AC losses may be reduced, and magnets may be stabilized, such as described in the peer-reviewed, academic review article "Multifilamentary coated conductors for ultra-high magnetic field applications", Anders Christian Wulff et a / ., Supercond. Sci. TechnoL 34 (2021) 053003, which is hereby incorporated by reference in entirety, and / or in the peer-reviewed, academic article "How filaments can reduce AC losses in HTS coated conductors: a review" by Grilli and Kairo, Supercond. Sci. TechnoL 29 (2016) 083002, which is also incorporated by reference in its entirety. A 'superconducting filament' may be understood to be an elongated superconducting element.

[0056] 'On the same side of the substrate' is understood as is common in the art, such as wherein a fictitious, planar plane is fitted to the substrate and 'the same side of the substrate' refers to a side of the substrate being on one side of said fitted, planar plane.

[0057] By 'parallel' may be understood substantially parallel, such as average directions deviating less than 10°, such as less than 5°, such as less than 2°, such as less than 1°. A direction may be understood to be an average direction, such as allowing that elements are non-parallel locally.

[0058] By 'said plurality of superconducting elements being arranged to be substantially parallel' may be understood, that superconducting elements are substantially parallel with each other, such as with at least one or more neighbouring superconducting element(s), such as with each of the other superconducting elements within said plurality of superconducting elements.

[0059] 'Layer' is to be understood as is common in the art, such as a level of material that is different from the material above or below it. It may be understood that lateral dimensions (such as x- and y-directions) of the layer are larger, such as at least 10 times larger, such as at least 100 times larger than a dimension in a direction orthogonal to the lateral directions. It is foreseen and encompassed that a layer might not be coherent, i.e., it may be possible that a layer comprises different portions within the layer, which are spatially separated from each other. In embodiments, any layer is a coherent layer.

[0060] By 'intermediate layer' may be understood a layer, which - at least at some point during manufacturing - is between other elements.

[0061] The intermediate layer may comprise, such as consists of, one or more of the elements of the periodic table selected from Cu, Ni, Ag and / or Au, such as one or more of the elements of the periodic table selected from Cu and / or Ni, such as Cu.

[0062] By 'the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element' may be understood that for each superconducting element, a fictitious, rectilinear line may be drawn, which intersects the superconducting element and which furthermore on one side of the superconducting element intersects the substrate and on the other side of the superconducting element intersects the intermediate layer, and wherein the intermediate layer is rigidly connected optionally directly to the superconducting element.

[0063] By 'opposite layer' may understood may be understood a layer, which - at least at some point during manufacturing - is positioned oppositely with respect to a least one other element.

[0064] The opposite layer may comprise, such as consist of, one or more metallic elements.

[0065] The opposite layer may comprise, such as consist of, one or more of the elements of the periodic table selected from Sn, Zn, Ni, Be, P, C, B, Cr, Al, Mg, Si, Fe, Nb, and / or Cd, such as one or more of the elements of the periodic table selected from Sn, Zn, Ni, Be and / or P, such as Sn. A possible advantage of this may be that it allows forming an alloy with the intermediate layer, such as said alloy comprising, such as consisting of, bronze, such as the alloy being a Cu alloy, such as an alloy of the element pair Cu-Sn, Cu-Zn, Cu-Ni, Cu-Be, or Cu-P, or such as the alloy being a Ni-alloy, such as an alloy of the element pair Ni-Sn, Ni-P, or Ni-Cu.

[0066] The opposite layer may comprise, such as consist of, one or more elements, such as one or more elements of the periodic table, being a semi-metal or a metalloid or a non-metal or an inter-metal, such as C (carbon), such as the alloy being a Cu alloy with carbon, such as copper carbide.

[0067] By 'adjoining the intermediate layer' may be understood that the opposite layer is in direct contact with the intermediate layer, such as no separation and no other elements between them at least in one or more points of contact. It is understood that an interface between the intermediate layer and the opposite layer is provided at the point or points (of contact) where they are adjoining.

[0068] By 'on the opposite side of the intermediate layer with respect to the superconducting elements' may be understood that a fictitious, rectilinear line may be drawn, which intersects the intermediate layer and which furthermore on one side of the intermediate layer intersects the superconducting elements and on the other side of the intermediate layer intersects the opposite layer.

[0069] By 'a composition of the opposite layer is different with respect to a composition of the intermediate layer' may be understood that a difference is sufficiently large to enable forming an alloy (rather than just merging two similar or identical layers), such as so that for at least one metal within the intermediate layer, there is another element, such as a metal or a semimetal or a metalloid or a non-metal or inter-metal, in the opposite layer, which is not present in the same amount in the intermediate layer, such as the w / w-percentage differs by at least 1 percentage point, such as at least 10 percentage points.

[0070] In an embodiment, the opposite layer comprises, such as consists of a metal, and wherein optionally a metallic composition of the opposite layer is different with respect to a metallic composition of the intermediate layer.

[0071] By 'a metallic composition of the opposite layer is different with respect to a metallic composition of the intermediate layer' may be understood that a difference is sufficiently large to enable forming an alloy (rather than just merging two similar or identical layers), such as so that for at least one metal within the intermediate layer, there is another metal in the opposite layer, which is not present in the same amount in the intermediate layer, such as the w / w-percentage differs by at least 1 percentage point, such as at least 10 percentage points.

[0072] 'Alloy' is understood as is common in the art, such as an alloy being a mixture of chemical elements of which at least one or both is a metallic element, such as an alloy being a substance composed of two or more metals or of a metal and a nonmetal, such as two or more metals being intimately united or a metal and a nonmetal being intimately united.

[0073] 'Forming an alloy layer by alloying the intermediate layer and the opposite layer at their interface' is understood as is common in the art, such as exposing the opposite layer and the intermediate layer (at least at their interface) to conditions (such as an elevated temperature and a minimum period of time), which causes an alloying process to be initiated and continued for a period of time.

[0074] It may furthermore be understood that the forming of an alloy layer implies that a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, is formed. By 'thickness' may in this context be understood a size along a dimension orthogonal to a surface of the alloy layer.

[0075] According to an embodiment, there is presented a method, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer: Remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

[0076] A possible advantage of the remaining portions of the intermediate layer, i.e., the intermediate objects, being spatially separated from each other may be that it enables avoiding that a current can run from one superconducting element to another superconducting element through the intermediate layer or the remaining portions thereof. This may in turn enable reducing, minimizing, or eliminating losses when the superconducting tape is used in alternating current (AC) applications.

[0077] A possible advantage of having an intermediate object comprising the part of the intermediate layer placed on the superconducting element is that the intermediate object may facilitate shunting, which may in turn enable reducing, minimizing, or eliminating a risk of local overheating (which may in turn enable reducing, minimizing, or eliminating a risk of serious damage, e.g., in case of defects) in the superconducting tape.

[0078] By 'spatially separated' may be understood that for any two points within any two remaining portions of the intermediate layer (with one point being in one remaining portion and the other point being in the other remaining portion), there is a finite, non-zero distance between said two points, such as said distance being at least 1 pm, such as at least 10 pm, such as at least 50 pm, such as at least 100 pm, such as at least 200 pm, such as at least 500 pm, such as at least 1 mm, such as at least 2 mm, such as at least 5 mm, such as at least 10 mm.

[0079] According to an embodiment, there is presented a method, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, an average electrical resistance, such as an electrical resistance per unit length, of a remaining portion of the intermediate layer is smaller, such as with respect to a situation prior to, such as immediately prior to, forming the alloy layer, for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as 100 % smaller.

[0080] A possible advantage of this may be that while the relatively lower average electrical resistance of the remaining part of the intermediate layer placed on the superconducting element may facilitate shunting (which may in turn enable reducing, minimizing, or eliminating a risk of local overheating - which may in turn enable reducing, minimizing, or eliminating a risk of serious damage, e.g., in case of defects - in the superconducting tape), the relatively higher average electrical resistance between the remaining parts of the intermediate layer enables decreasing the amount of current, which runs from one superconducting element to another superconducting element through the intermediate layer or the remaining portions thereof (which may in turn enable reducing, minimizing, or eliminating losses when the superconducting tape is used in alternating current (AC) applications).

[0081] By 'average electrical resistance' may be understood an electrical resistance per unit length, such as in a direction from one point to another point (such as from one side of a superconducting element the other side of the superconducting element or from a superconducting element to a neighbouring superconducting element).

[0082] By 'longitudinal (direction)' of an element, such as a superconducting element, may generally be understood, a lengthwise direction of the element, such as a direction along an axis (which may optionally be locally non-rectilinear), for which the element has the largest length from one end to the other. Additionally, or alternatively, in the context of current carrying elements, a longitudinal direction may be parallel with an average current direction during use.

[0083] According to an embodiment, there is presented a method, wherein during the step of forming the alloy layer, one or more sections of the intermediate layer become part of the alloy layer, so that gaps in the intermediate layer appear and / or increase in size, optionally so that remaining portions of the intermediate layer subsequent to forming the alloy layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

[0084] A possible advantage of this is that the step of forming the alloy layer facilitates reaping one or more of the above-mentioned advantages. Another possible advantage may be that it enables that preceding steps (such as deposition of layers) can be carried out in a manner resulting in a less optimal structure, because a more optimal structure can then be provided via the step of forming the alloy layer.

[0085] According to an embodiment, there is presented a method, wherein a ratio between a. an average electrical resistance such as an electrical resistance per unit length, of a remaining portion of the intermediate layer for a current passing in a cross- sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, and b. an average electrical resistance such as an electrical resistance per unit length, of a remaining portion of the intermediate layer for a current passing in a cross- sectional plane orthogonal to a longitudinal direction of a superconducting element from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, decreases during the step of forming the alloy layer, such as decreases by at least 1 %, such as decreases by at least 2 %, such as decreases by at least 5 %, such as decreases by at least 10 %, such as decreases by at least 50 %, such as decreases by at least 75 %, such as decreases by at least 90 %, such as decreases by at least 95 %,such as decreases by 100 %.

[0086] A possible advantage of this is that the step of forming the alloy layer facilitates reaping one or more of the above-mentioned advantages. Another possible advantage may be that it enables that preceding steps (such as deposition of layers) can be carried out in a manner resulting in a less optimal structure, because a more optimal structure can then be provided via the step of forming the alloy layer.

[0087] It is understood that a ratio between X and Y is understood to mean a ratio of X to Y, i.e., X / Y. According to an embodiment, there is presented a method, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, a resistance from one superconducting element to a neighbouring superconducting element increases, such as with respect to a situation prior to, such as immediately prior to, forming the alloy layer, such as increases by at least 1 %, such as at least 2 %, such as at least 5 %, such as at least 10 %, such as at least 50 %, such as at least 100 %, such as at least 1000 %.

[0088] According to an embodiment, there is presented a method, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, an electrical resistance from one superconducting element to a neighbouring superconducting element increases, such as with respect to a situation prior to, such as immediately prior to, forming the alloy layer, such as increases by at least 1 %, such as at least 2 %, such as at least 5 %, such as at least 10 %, such as at least 50 %, such as at least 100 %, such as at least 1000 %.

[0089] A possible advantage of this is that the step of forming the alloy layer facilitates reaping one or more of the above-mentioned advantages. Another possible advantage may be that it enables that preceding steps (such as deposition of layers) can be carried out in a manner resulting in a less optimal structure, because a more optimal structure can then be provided via the step of forming the alloy layer.

[0090] According to an embodiment, there is presented a method, wherein the alloying, such as the alloying process, is stopped at a time when remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other, and / or when an average electrical resistance, such as an electrical resistance per unit length, of a remaining portion of the intermediate layer is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as 100 % smaller.

[0091] A possible advantage of this is that the step of forming the alloy layer facilitates reaping one or more of the above-mentioned advantages, e.g ., due to remaining portions of the intermediate layer still being present when the alloying process is stopped.

[0092] By 'the alloying is stopped' may be understood changing conditions from a set of conditions at which alloying takes place at a first rate, to a set of conditions wherein alloying takes place at a second rate, wherein the first rate is higher than the second rate, such as at least 10 % higher, such as at least 20 % higher, such as at least 50 % higher, such as at least 100 % higher, such as at least 500 % higher, such as at least 1000 % higher.

[0093] According to an embodiment, there is presented a method, wherein the substrate is partially or fully removed . A possible advantage of this may be that a lighter superconducting tape is provided, and that a higher engineering current density can be achieved .

[0094] 'Engineering current density' is understood as is common in the art, such as wherein the engineering current density is defined as the current density for a cross-sectional area of the superconducting tape, including superconducting material, and optionally other materials if present, such as core, capping, substrate, one or more buffer layers or buffer-stacks and stabilizing layers.

[0095] According to an embodiment, there is presented a method, wherein : a. The average electrical resistance is the electrical resistance per unit length, b. The first point and the second point are chosen to be as distant with respect to each other as possible, c. The third point and the fourth point are chosen to be as close to each other as possible, d. The first point, the second point and the third point are each chosen to be as close as possible to the superconducting element, such as adjoining the superconducting element, and e. The fourth point is chosen to be as close as possible to the neighbouring superconducting element, such as adjoining the neighbouring superconducting element.

[0096] If the choices are conflicting, they must be prioritized according to their sequence in the above list.

[0097] According to an embodiment, there is presented a method, wherein producing the superconducting tape, such as including the forming of an alloy layer, is carried out so that a temperature of the plurality of superconducting elements does not exceed 200° C, such as does not exceed 175°C, such as does not exceed 150 °C, such as does not exceed 125° C such as does not exceed 100° C, such as does not exceed 75°C, such as does not exceed 50 °C, such as does not exceed 40° C.

[0098] A possible advantage may be that this enables reducing degradation of, or even maintaining, the (superconducting) properties of the superconducting elements. Producing the superconducting tape with (below) this temperature may be realized, e.g., by providing of material, such as material of the intermediate layer and / or the alloy layer, via plating (e.g., as opposed to soldering or sintering, which requires relatively higher temperatures).

[0099] 'Does not exceed' may be understood from a practical point of view and / or such as encompassing embodiments wherein the temperature is exceeded yet for only a period (which may be only short and / or inconsequential period), such as wherein a temperature does exceed a limit, such as the given limit, but only for a period of 10 seconds or less, such as 5 seconds or less, such as 2 seconds or less, such as 1 second or less. A 'period' may in this context be understood as an uninterrupted period.

[0100] According to an embodiment, there is presented a method, wherein producing the superconducting tape, such as including the forming of an alloy layer, is carried out so that a temperature of the plurality of superconducting elements does not continuously exceed 200° C, such as does not continuously exceed 175°C, such as does not continuously exceed 150 °C, such as does not continuously exceed 125° C such as does not continuously exceed 100° C, such as does not continuously exceed 75°C, such as does not continuously exceed 50 °C, such as does not continuously exceed 40° C, for an uninterrupted period of time being 10 seconds or more, such as 5 seconds or more, such as 3 seconds or more, such as 2 seconds or more, such as 1 second or more.

[0101] According to an embodiment, there is presented a method, wherein providing the intermediate layer comprises plating, such as electroplating and / or wherein providing the opposite layer comprises plating, such as electroplating. One or more possible advantages include that it (plating) enables a simple and / or scalable method of manufacture. Another possible advantage may be that it enables keeping the temperature relatively low, which may in turn be beneficial for energy efficiency during manufacturing and / or for reducing, minimizing or eliminating degradation of the (superconducting) properties of the superconducting elements.

[0102] According to an embodiment, there is presented a method, wherein the intermediate layer comprises copper (Cu), wherein the opposite layer comprises tin (Sn), and wherein the alloy layer comprises an alloy of the element pair Cu-Sn, such as bronze.

[0103] One or more possible advantages include that cupper has a high thermal conductivity and / or that tin can be alloyed into the cupper.

[0104] According to an embodiment, there is presented a method, wherein the intermediate layer comprises copper (Cu), wherein the opposite layer comprises zinc (Zn), and wherein the alloy layer comprises an alloy of the element pair Cu-Zn.

[0105] According to an embodiment, there is presented a method, wherein the intermediate layer comprises copper (Cu), wherein the opposite layer comprises aluminium (Al), and wherein the alloy layer comprises an alloy of the element pair Cu-AL

[0106] According to a second aspect of the invention, there is presented a superconducting tape comprising : a. A substrate, b. An alloy layer, c. A plurality of superconducting elements, each of said superconducting elements being an elongated superconducting element, and said plurality of superconducting elements being substantially parallel, such as parallel, and placed on the substrate, such as wherein each of said superconducting elements are being on the same side of the substrate, and between the substrate and the alloy layer, and d. One or more intermediate objects, said one or more intermediate objects comprising, such as consisting of, a metal, and said one or more intermediate objects being arranged so that between each superconducting element and the alloy layer, there is a portion of the one or more intermediate objects, which portion is adjoining the alloy layer, wherein the alloy layer comprises, such as consists of, an alloy of at least the material of the one or more intermediate objects.

[0107] One or more advantages may be as described for the first aspect. According to an embodiment, there is presented a superconducting tape, wherein the one or more intermediate objects form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

[0108] One or more advantages may be as described for the first aspect.

[0109] According to an embodiment, there is presented a superconducting tape, wherein an average electrical resistance, such as an electrical resistance per unit length, of the one or more intermediate objects is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as 100 % smaller.

[0110] One or more advantages may be as described for the first aspect.

[0111] According to an embodiment, there is presented a superconducting tape, wherein the one or more intermediate objects are absent, such as absent at one or more points between neighbouring portions and / or such as wherein portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer and wherein said intermediate objects are spatially separated from each other, or comprising a thickness at one or more points between neighbouring portions, such as between the neighbouring portions which is smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, compared to a thickness at the portions, such as wherein thickness is to be measured in a direction orthogonal to a longitudinal direction of the superconducting elements at one or both neighbouring portions and in a direction being normal to a surface of the one or more intermediate objects, such as the surface facing the superconducting elements. By 'thickness' may in this context be understood a size along a dimension orthogonal to a surface of the one or more intermediate objects.

[0112] A possible advantage may be that this structure realizes one or more advantages as described for the first aspect.

[0113] According to an embodiment, there is presented a superconducting tape, comprising an opposite layer, said opposite layer: a. Adjoining the alloy layer on the opposite side of the alloy layer with respect to the one or more intermediate objects, b. Optionally comprising, such as consisting of, a metal, wherein a metallic composition of the opposite object is different with respect to a metallic composition of the one or more intermediate objects, wherein the alloy layer is an alloy of the opposite layer.

[0114] A possible advantage may be that the presence of an opposite layer may enable (continued) alloying, e.g., if it is deemed advantageous to convert more of the intermediate layer into the alloy layer.

[0115] According to an embodiment, there is presented a superconducting tape, wherein gaps in the alloy layer, if present, are at most 50 pm, such as at most 25 pm, such as at most 10 pm, such as at most 5 pm, such as at most 1 pm, such as at most 500 nm.

[0116] A possible advantage may be that due to the relatively small size of said gaps, the thermal properties (such as the capability of conducting thermal energy away from a defect where resistive heating takes place) is degraded only to a minor extent.

[0117] According to an embodiment, there is presented a superconducting tape, wherein the alloy layer is coherent, such as forming a coherent layer adjoining said parts.

[0118] A possible advantage may be that good thermal properties (such as the capability of conducting thermal energy away from a defect where resistive heating takes place) is achieved.

[0119] According to an embodiment, there is presented a superconducting tape, wherein the plurality of superconducting elements defines a fictitious plane, such as said fictitious plane being planar or cylindrical, and wherein said portions (of the one or more intermediate objects) comprise material of the one or more intermediate objects traversed by fictitious lines intersecting the superconducting elements and being orthogonal to said plane.

[0120] A possible advantage may be that said portions are at least present outside of said plane, which means that the dimension orthogonal to said plane is utilized.

[0121] According to an embodiment, there is presented a superconducting tape, wherein the substrate comprises undercut sections, such as located adjacent to edges of the superconducting elements.

[0122] An advantage may be that it enables depositing spatially separated portions of material on the substrate, e.g., via a line-of-sight depositing process.

[0123] By 'undercut sections' is understood sections where undercut volumes are etched in said sections, which volumes may be below remaining portions of the substrate (such as between remaining portions of the substrate). Thus, an undercut volume may be shadowed by overhanging portions of the substrate. Thus, when a material is deposited on the substrate using a line-of- sight process for deposition of material in a direction following the up-down- axis (such as an axis orthogonal to a plane of the substrate, such as the surface of the substrate) from a position above the substrate, and undercut volumes have been formed in the substrate (at the undercut sections), then the material is not deposited below the undercut volumes.

[0124] By a 'line-of-sight' process is understood any process which enables depositing material only on positions of a substrate which may be seen along a straight line from another position, such as a position above the substrate. 'Line-of-sight' process is thus construed broadly to comprise processes where the deposited material follows straight lines prior to deposition and processes for deposition which has a similar effect. In a particular embodiment, the line-of- sight process is any one of vapor deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, thermal evaporation, e-beam assisted deposition, ionized jet deposition, die coating, bubble jet coating and ink-jet coating. In particular embodiments, 'line-of-sight' is understood to be a process wherein the deposited material has its origin from a source and travels in a direct line therefrom to the position where it is deposited. In other words, there can only be deposited material on positions from which there can be drawn a straight line to the source which does not traverse any obstacles.

[0125] According to an embodiment, there is presented a superconducting tape, wherein the alloy is confined to be present only on one side of the superconducting elements.

[0126] A possible advantage may be that this enables a light and / or compact structure. According to an embodiment, there is presented a superconducting tape, wherein the one or more intermediate objects comprises, such as consists of, one or more of the elements of the periodic table selected from Cu, Ni, Ag and / or Au, such as one or more of the elements of the periodic table selected from Cu and / or Ni, such as Cu.

[0127] It may be understood that the intermediate layer (also in the context of the method according to the first aspect) may comprise, such as consist of the same elements as mentioned above for the one or more intermediate objects.

[0128] A possible advantage may be that these elements, such as Cu, has a high electrical conductivity (which may in turn be beneficial for shunting) and / or high thermal conductivity (which may in turn be beneficial for thermal management).

[0129] According to an embodiment, there is presented a superconducting tape, wherein the alloy layer comprises, such as consists of, an alloy of one or more of the elements of the periodic table selected from Sn, Zn, Ni, Be, P, C, B, Cr, Al, Mg, Si, Fe, Nb, and / or Cd, such as one or more of the elements of the periodic table selected from Sn, Zn, Ni, Be and / or P, such as Sn. Said alloy may be comprising, such as consisting of, bronze, such as the alloy being a Cu alloy, such as an alloy of the element pair Cu-Sn. Said alloy may be comprising, such as consist of, an alloy of any of the element pairs Cu-Zn, Cu-Ni, Cu-Be, or Cu-P. Said alloy may be comprising, such as consist of, a Ni-alloy, such as an alloy of the element pair Ni-Sn, Ni-P, or Ni-Cu.

[0130] It may be understood that the intermediate layer (also in the context of the method according to the first aspect) may comprise, such as consist of the same elements as mentioned above for the one or more alloy layer of the superconducting tape.

[0131] A possible advantage may be that these compositions, such as Cu-Sn, such as bronze, has an advantageous relationship (low ratio) between a (low) electrical conductivity (which may in turn be beneficial for avoiding AC losses) and (high) thermal conductivity (which may in turn be beneficial for thermal management).

[0132] According to an embodiment, there is presented a superconducting tape, wherein a length, such as a maximum dimension in a longitudinal direction of the tape, is equal to or larger than 1 m, such as equal to or larger than 2 m, such as equal to or larger than 3 m, such as equal to or larger than 5 m, such as equal to or larger than 8 m, such as equal to or larger than 10 m, such as equal to or larger than 100 m, such as equal to or larger than 1 km, such as equal to or larger than 10 km, such as equal to or larger than 100 km, such as equal to or larger than 1000 km.

[0133] A possible advantage of relatively large length of the superconducting tape may be that it enables carrying current across a correspondingly large distance. The length of the tape may be understood as the largest dimension of the tape. It may be understood that the length is to be measured along the tape and / or for the configuration of the tape wherein the length is maximum (such as for example the length of a tape would be the length of the rolled-out tape rather than a length or diameter of a coil comprising a rolled-up tape).

[0134] According to an embodiment, there is presented a superconducting tape, wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm. By 'thickness' may in this context be understood a size along a dimension orthogonal to a surface of the alloy layer.

[0135] According to an embodiment, there is presented a superconducting tape, wherein each of the superconducting elements comprises a biaxially textured superconductor material, such as a coated conductor, such as an epitaxially grown superconducting layer, such as an anisotropic superconducting layer, such as a second-generation high temperature superconductor, such as a rare-earth barium copper oxide (REBCO) superconducting layer, such as a REBa2CusO7-x superconducting layer, where x =0-0.65, and where RE = Y, Gd, Nd or Eu.

[0136] According to an embodiment, there is presented a superconducting tape, which furthermore comprises an encircling coating, wherein the encircling coating is electrically non-conducting.

[0137] A possible advantage may be that depending on the context, e.g., if a superconducting tape is placed adjacent to, such as adjoining, other superconducting tapes, one or more positive effects of the alloy layer could be negated by effects transmitted via conducting an electrically conducting path between the superconducting elements in one superconducting tape and the superconducting elements in an adjacent superconducting tape, yet with the encircling coating, this electrically conducting path is broken by the electrically nonconducting electrical coating.

[0138] By 'encircling' may be understood that the coating substantially encircles, such as encircles, such as fully encircles at least the superconducting elements, the intermediate layer and the alloy layer, such as encircles around at least 300 degrees, such as at least 330 degrees, such as at least 345 degrees, such as 360 degrees, and wherein the encircling is around a longitudinal axis of the superconducting tape (such as the remainder of the superconducting tape when excluding the encircling coating).

[0139] 'Electrically non-conducting' may be understood as is common in the art, such as a material where electrical charges cannot flow freely in which the resistivity is above 1015Ohm*m. Examples of non-conducting materials may include metal oxides, such as AI2O3. The encircling coating may for example comprise, such as consist of, the same material as the intermediate layer or the opposite layer, such as Cu or Sn, after having undergone a reaction, such as a chemical reaction, such as thereby forming an electrically non-conducting oxide or carbide, such as copper oxide, tin oxide, copper carbide or tin carbide.

[0140] According to an embodiment, there is presented a superconducting tape, wherein each of said superconducting elements are being on the same side of the substrate.

[0141] According to an embodiment, there is presented a superconducting tape, wherein:

[0142] • The average electrical resistance is the electrical resistance per unit length,

[0143] • The first point and the second point are chosen to be as distant with respect to each other as possible,

[0144] • The third point and the fourth point are chosen to be as close to each other as possible,

[0145] • The first point, the second point and the third point are each chosen to be as close as possible to the superconducting element, such as adjoining the superconducting element, and

[0146] • The fourth point is chosen to be as close as possible to the neighbouring superconducting element, such as adjoining the neighbouring superconducting element.

[0147] According to an embodiment, there is presented a superconducting tape,

[0148] • wherein portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer and wherein said intermediate objects are spatially separated from each other, and / or

[0149] • wherein portions of the intermediate layer have a thickness at one or more points between neighbouring portions, such as neighbouring portions positioned between each superconducting element and the alloy layer, which is smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, compared to a thickness at the neighbouring portions, such as wherein thickness is to be measured in a direction orthogonal to a longitudinal direction of the superconducting elements at one or both neighbouring portions and in a direction being normal to a surface of the one or more intermediate objects, such as the surface facing the superconducting elements.

[0150] According to an embodiment, there is presented a superconducting tape, wherein the superconducting tape is the result of a production, such as a production process, according to the first aspect.

[0151] According to an embodiment, there is presented a superconducting tape, wherein the superconducting tape is the result of a production, such as a production process,

[0152] • which is carried out so that a temperature of the plurality of superconducting elements does not exceed 200° C, such as does not exceed 175°C, such as does not exceed 150 °C, such as does not exceed 125° C such as does not exceed 100° C, such as does not exceed 75°C, such as does not exceed 50 °C, such as does not exceed 40° C, and / or

[0153] • wherein providing the intermediate layer comprises plating, such as electroplating.

[0154] According to an embodiment, there is presented a superconducting tape, wherein each of said superconducting elements comprises a superconducting material, and wherein a minimum distance from the superconducting material of each superconducting element to the substrate is equal to 10 pm or less, such as 8 pm or less, such as 6 pm or less, such as 5 pm or less, such as 4 pm or less, such as 3 pm or less, such as 2 pm or less, such as 1 pm or less.

[0155] A possible advantage is that a short distance from substrate to superconducting material enables that the texture of the substrate may advantageously be employed for endowing a certain texture to the superconducting material. Another possible advantage may be that it enables a compact structure and / or a high engineering current density. Another advantage may be that it enables a simple and / or compact structure, e.g., in that a substrate supporting a plurality of superconducting elements may double function both as (compact) support and as a means for influencing or controlling texture of the superconducting material.

[0156] According to an embodiment, there is presented a superconducting tape, wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, wherein each of said superconducting elements comprises a superconducting material, and wherein a minimum distance from the superconducting material of each superconducting element to the substrate is equal to 10 pm or less, such as 8 pm or less, such as 6 pm or less, such as 5 pm or less, such as 4 pm or less, such as 3 pm or less, such as 2 pm or less, such as 1 pm or less. According to an embodiment, there is presented a superconducting tape, wherein the substrate comprises an alloy, such as metallic alloy comprising at least 10.5 wt% chromium and less than 1.2 wt% carbon, and optionally comprising nickel, such as said alloy being chosen from a group comprising, such as consisting of, Hastelloy® stainless steel and / or Inconel®.

[0157] An advantage of this may be that such substrate has or can be chosen to have one or more or all of: an appropriate thermal expansion coefficient, such as thermal expansion compatibility relative to superconductor material of the superconducting element, appropriate mechanical properties, such as for the purpose of coated conductor fabrication, oxidation and corrosion resistance, texture compatibility for epitaxial growth, and / or chemical compatibility with buffer layers, such as wherein the superconductor material is a REBCO material.

[0158] According to an embodiment, there is presented a superconducting tape, wherein the substrate comprises Hastelloy®, stainless steel and / or Inconel®.

[0159] According to an embodiment, there is presented a superconducting tape, wherein the substrate comprises Hastelloy®.

[0160] An advantage of this may be improved electrical properties for a simple and / or compact structure.

[0161] According to an embodiment, there is presented a superconducting tape,

[0162] • wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, and

[0163] • wherein the substrate comprises an alloy, such as metallic alloy comprising at least 10.5 wt% chromium and less than 1.2 wt% carbon, and optionally comprising nickel, such as said alloy being chosen from a group comprising, such as consisting of, Hastelloy®, stainless steel and / or Inconel®.

[0164] An advantage of this may be improved electrical properties, partially due to the thickness of the alloy layer, partially due to the substrate material.

[0165] According to an embodiment, there is presented a superconducting tape, wherein each of said superconducting elements comprises, such as consists of, rare-earth barium copper oxide. According to an embodiment, there is presented a superconducting tape, wherein the intermediate layer comprises copper (Cu), and wherein the alloy layer comprises an alloy of the element pair Cu-Sn, such as bronze.

[0166] According to an embodiment, there is presented a method, wherein the intermediate layer comprises copper (Cu), and wherein the alloy layer comprises an alloy of the element pair Cu-Zn.

[0167] According to an embodiment, there is presented a method, wherein the intermediate layer comprises copper (Cu), and wherein the alloy layer comprises an alloy of the element pair Cu-AL

[0168] According to an embodiment, there is presented a method, wherein the substrate is non- planar and / or has grooves.

[0169] A possible advantage of this may be that it enables similar or corresponding non-planarity and / or grooves of the intermediate layer, e.g., during production, which in turn enables that an alloying step can advantageously modify the intermediate layer in a non-homogeneous manner.

[0170] According to an embodiment, there is presented a method, wherein the substrate has grooves.

[0171] A 'groove' is to be understood as is common in the art, such as elongated recessed region, channel, or depression formed in a body, such as a substrate. It may be understood that both parts of the surface of the body adjacent to the groove on either side of the groove lie substantially within, such as within, the same planar plane.

[0172] According to an embodiment, there is presented a method,

[0173] • wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, and

[0174] • wherein the substrate is non-planar and / or has grooves.

[0175] An advantage of this may be improved electrical properties, which may be realized in a simple manner, since the non-planarity and / or grooves of the substrate enables similar or corresponding non-planarity and / or grooves of the intermediate layer, e.g., during production, which in turn enables that an alloying step can advantageously modify the intermediate layer in a non-homogeneous manner, which yields the improved electrical properties due to the significant thickness of the alloy layer.

[0176] According to an embodiment, there is presented a method, wherein the substrate is non- planar such that for one or more pairs of neighbouring superconducting elements, such as nearest neighbouring superconducting elements, in at least one cross-sectional plane orthogonal to a longitudinal direction of one or both of the superconducting elements in the pair of neighbouring superconducting elements, a straight line can be drawn from a. a primary point in the substrate, wherein the primary point in the substrate is the point in the substrate closest to the superconducting element on the opposite side of the superconducting element with respect to the intermediate layer and the alloy layer and on a rectilinear path traversing a geometrical center of the superconducting element and being orthogonal to another rectilinear path intersecting the two points in the superconducting element being farthest apart, and b. a secondary point in the substrate, wherein the secondary point in the substrate is the point in the substrate closest to the other one of the superconducting elements in the pair of neighbouring superconducting elements on the opposite side of the other one of the superconducting elements in the pair of neighbouring superconducting elements with respect to the intermediate layer and the alloy layer and on a rectilinear path traversing a geometrical center of the other one of the superconducting elements in the pair of neighbouring superconducting elements and being orthogonal to another rectilinear path intersecting the two points in the other one of the superconducting elements in the pair of neighbouring superconducting elements being farthest apart, and wherein the primary point and the secondary point are on the same side of a rectilinear path intersecting the geometrical centers of the superconducting element and the other one of the superconducting elements in the pair of neighbouring superconducting elements, and wherein there is one or more points on said straight line along said straight line between the primary point and the secondary point, wherein a minimum distance from the one or more points on said line to the substrate, such as to the surface of the substrate, c. is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm, d. is optionally at most 4 mm, such as at most 2 mm, such as at most 1 mm, e. such as is within ]10 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm;

[0177] 1 mm[.

[0178] The open brackets "]x; y[" generally indicate that neither x nor y is included in the interval, yet all numbers therebetween are included. According to an embodiment, there is presented a method, wherein the substrate has grooves and wherein

[0179] • a distance 233a, such as a first distance and / or a depth of the grooves, between i. a plane being parallel with a surface of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, such as being tangential with the protrusions between the grooves 234, and ii. a plane being tangential to the bottom of the plurality of grooves, as measured in a direction orthogonal to the plane of the first side of the substrate is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm, and

[0180] • The distance 233a, such as a first distance and / or a depth of the grooves, is optionally within ]100 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm; 1 mm[.

[0181] According to an embodiment, there is presented a method, wherein the substrate has grooves and wherein

[0182] • a distance 233b, such as a second distance and / or a width of the grooves, from i. an edge, such as the beginning of an edge, such as the end of the planar portion of the substrate outside of the groove, of a protrusion on one side of groove, to ii. an edge of a protrusion on another side of a groove as measured in a direction parallel with the plane of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, and orthogonal to a longitudinal direction of the grooves is at least 1 micrometres, such as at least 2 micrometres, such as at least 5 micrometres, such as at least 10 micrometres, such as at least 30 micrometres, such as at least 100 micrometres, such as at least 200 pm,

[0183] • the distance 233b, such as a second distance and / or a width of the grooves, is at most 1 mm, such as at most 500 pm, such as at most 200 pm, such as at most 100 pm, and / or the distance 233b, such as a second distance and / or a width of the grooves, is within 1 micrometer-1 mm, such as within 10 pm-500 pm.

[0184] According to an embodiment, there is presented a method, wherein the substrate has grooves and wherein

[0185] • a distance 233c, such as a third distance, between adjacent grooves measured in a direction parallel with the plane of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, and orthogonal to a longitudinal direction of the grooves is at least 100 pm and / or at most 2 mm, such as wherein the distance, such as the third distance, 233c is within ]100 pm; 2 mm[, such as within ]200 pm; 1 mm[.

[0186] According to a third aspect of the invention, there is presented a use of a superconducting tape as prepared by a method according to the first aspect of the invention or the superconducting tape according to the second aspect of the invention, for carrying an electrical current, such as at least 1 mA, such as at least 10 mA, such as at least 100 mA, such as at least 1 A, such as at least 10 A, such as at least 100 A, such as at least 1 kA.

[0187] BRIEF DESCRIPTION OF DRAWNGS

[0188] The first, second, and third aspect according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0189] FIG. 1 is a flowchart illustrating a method according to an embodiment of the invention.

[0190] FIGs. 2-10 shows schematic illustrations depicting steps in a method according to an embodiment of the invention.

[0191] FIG. 11 shows a schematic illustration depicting an alternative step with respect to the step depicted in FIG. 10.

[0192] FIGs. 12-18 and 20-21 shows schematic illustrations depicting steps in another method according to another embodiment of the invention. FIG. 19 shows a schematic illustration depicting an alternative step with respect to the step depicted in FIG. 18.

[0193] FIG. 22 shows a SEM micrograph showing an embodiment of a superconducting tape.

[0194] DETAILED DISCLOSURE OF THE INVENTION

[0195] FIG. 1 is a flowchart illustrating a method according to an embodiment of the invention, said method being a method 100 for producing a superconducting tape, said method comprising sequentially: a. Providing a Hastelloy substrate 102, b. Providing a plurality of superconducting REBCO elements on the substrate 104, each of said superconducting elements being an elongated superconducting element, each of said superconducting elements being on the same side of the substrate, and said plurality of superconducting elements being arranged to be substantially parallel, such as parallel, c. Providing an intermediate layer 106, said intermediate layer comprising, such as consisting of, a metal, which in the present example is copper (Cu), and said intermediate layer being arranged at least partially, such as partially or fully, such as fully, on the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element, d. Providing an opposite layer 108 adjoining the intermediate layer on the opposite side of the intermediate layer with respect to the superconducting elements, said opposite layer comprising, such as consisting of, a metal, which in the present example is tin (Sn), wherein a metallic composition of the opposite layer is different with respect to a metallic composition of the intermediate layer, and e. Forming an alloy layer 110, which in the present example is bronze, by alloying the intermediate layer and the opposite layer at their interface.

[0196] The alloying, such as the alloying process, is then stopped 112 at a time when remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other. Subsequently, the substrate is removed 114.

[0197] Finally, an encircling coating is provided 116, wherein the encircling coating is electrically non-conducting.

[0198] FIGs. 2-10 shows schematic illustrations depicting steps in a method according to an embodiment of the invention, said method being a method for producing a superconducting tape according to the second aspect of the invention.

[0199] FIG. 2 shows a substrate 228 being a planar metal substrate without grooves in the first side, wherein the substrate has a first side 231 and a second side 232, such as wherein the first side is opposite the second side.

[0200] FIG. 3 shows the substrate 230 after forming a plurality of grooves 234 in the first side of the substrate, and after forming one or more undercuts 236 at each groove (as indicated by the dashed lines delimiting the shadowed, undercut portions of each groove).

[0201] FIG. 3 also illustrates dimensions of the grooves 234. FIG. 3 is indicated a distance 233a between a plane (as indicated with the upper horizontal dashed line) being parallel with an (upper (in the figure)) surface of the first side of the substrate, such as being tangential with the protrusions between the grooves 234, and a plane (as indicated with the lower horizontal dashed line) and a plane being tangential to the bottom of the plurality of grooves, i.e., a depth of the grooves as measured in a direction orthogonal to the plane of the first side of the substrate (i.e., measured in the vertical / up-down direction in the plane of the paper of the figure). Said distance 233a or depth is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm. Said distance 233a or depth may furthermore be at most 4 mm, such as at most 2 mm, such as at most 1 mm. Said distance 233a or depth may be within ]10 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm; 1 mm[ (where the open brackets "]x; y[" indicate that neither x nor y is included in the interval, yet all numbers therebetween are included). Furthermore is indicated a dimension or width 233b of the grooves, i.e., the distance from an edge (such as the beginning of an edge, such as the end of the planar portion of the substrate outside of the groove) of a protrusion on one side of groove to an edge of a protrusion on another side of a groove as measured in a direction parallel with the plane of the first side of the substrate and orthogonal to a longitudinal direction of the grooves (i.e., measured in the horizontal and left-right direction in the plane of the paper of the figure). The dimension or width 233b may be at least 1 micrometre, such as at least 2 micrometres, such as at least 5 micrometres, such as at least 10 micrometres, such as at least 30 micrometres, such as at least 100 micrometres, such as at least 200 micrometres. The dimension or width 233b may be at most 1 mm, such as at most 500 pm, such as at most 200 pm, such as at most 100 pm. The dimension or width 233b may be within 1 micrometer-1 mm, such as within 10 pm-500 pm. There is in Fig. 3 furthermore indicated a distance 233c between adjacent grooves which is measured in the same direction as the width 233b. The distance 233c may be at least 100 pm. The distance 233c may be at most 2 mm. The distance 233c may be within ]100 pm; 2 mm[, such as within ]200 pm; 1 mm[.

[0202] FIG. 4 shows the substrate 230 after applying on the substrate a coating 238 comprising a high-temperature superconductor stack, so that for each groove within the plurality of grooves a first part of the coating on a first side of the groove is physically disconnected, from a second part of the coating on a second side of the groove, wherein the second side of the feature of the groove is opposite of the first side of the feature of the groove. Furthermore, portions of coating material can be seen in the grooves.

[0203] The disconnected coating 238 comprising a high-temperature superconductor stack may be seen as corresponding to a plurality of superconducting elements, wherein each of said superconducting elements being on the same side of the substrate, e.g., in the sense that in the depicted cross-sectional plane being orthogonal to the longitudinal direction of the substrate, a rectilinear line (the dashed line in the figure) can be drawn through a geometrical centre (as indicated by the full-drawn cross in the figure) of the substrate and oriented so as to be parallel with a vector between the two points in the substrate being farthest apart with respect to each other (the diagonally opposite points of the substrate), wherein each of the superconducting elements are being partially or fully on the same side of the rectilinear line.

[0204] FIG. 5 shows a method step of providing an intermediate layer by depositing intermediate layer material 240 in a near line-of-sight process as illustrated via the arrows 242, wherein the near line-of-sight process is indicated by the arrows being slightly non-parallel, wherein the near line-of-sight process (i.e., the process not being an ideal line-of-sight process) may be achieved by having a certain pressure, and which may have the effect that while some directionality may be retained, it may also be possible to deposit material below shadowing structures, such as deposit material in the undercut sections 236.

[0205] FIG. 6 shows the substrate with the intermediate layer 244, wherein parts 246 of the intermediate layer 244 are coherently bound to each other, albeit via thinner parts 250 at the edges of the undercut sections connecting to other parts 248 in the grooves. FIG. 7 shows a method step of providing an opposite layer by depositing opposite layer material 252 in a non-line-of-sight process as illustrated via the multiple-directional straight arrows 254.

[0206] FIG. 8 shows the substrate with the opposite layer 256.

[0207] FIG. 9 shows the superconducting tape 200 after forming an alloy layer 258 by alloying the intermediate layer 244 and the opposite layer 256 at their interface. The figure also shows that remaining portions of the intermediate layer form a plurality of intermediate objects 260 arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other. The spatial separation has been realized by the thin portions 250 previously indicated in FIG. 6 being entirely turned into the alloy layer 258 (as opposed to the thicker parts 246 also shown in FIG. 6 having only had a part of them being turned into the alloy layer 258), leaving behind gaps 262 in the intermediate layer between remaining portions of the intermediate layer.

[0208] FIG. 10 shows the superconducting tape 1000 wherein the opposite layer has been removed.

[0209] FIG. 11 shows an alternative with the superconducting tape 1100 wherein the substrate has been removed. In another alternative, both opposite layer and substrate is removed.

[0210] FIGs. 12-18 and 20-21 shows schematic illustrations depicting steps in another method according to another embodiment of the invention, said method being a method for producing a superconducting tape according to the second aspect of the invention.

[0211] FIG. 12 shows a superconducting tape comprising a substrate 1228 being a planar metal substrate without grooves in the first side, wherein the substrate has a first side 1231 and a second side 1232, such as wherein the first side is opposite the second side. The superconducting tape furthermore comprises a layer 1238 of superconducting material on the substrate.

[0212] FIG. 13 shows the superconducting tape after forming a plurality of trapezoidal shaped grooves 1234 in the layer 1238 of superconducting material and the first side of the substrate 1230, e.g., via mechanically grinding or etching, thereby forming inclined edges FIG. 13 also illustrates dimensions of the grooves 1234. FIG. 13 is indicated a distance 1233a between a plane (as indicated with the upper horizontal dashed line) being parallel with an (upper (in the figure)) surface of the first side of the substrate, such as being tangential with the protrusions between the grooves 1234, and a plane (as indicated with the lower horizontal dashed line) and a plane being tangential to the bottom of the plurality of grooves, i.e., a depth of the grooves as measured in a direction orthogonal to the plane of the first side of the substrate (i.e., measured in the vertical / up-down direction in the plane of the paper of the figure). Said distance 1233a or depth is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm. Said distance 1233a or depth may furthermore be at most 4 mm, such as at most 2 mm, such as at most 1 mm. Said distance 1233a or depth may be within ]10 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm; 1 mm[ (where the open brackets "]x; y[" indicate that neither x nor y is included in the interval, yet all numbers therebetween are included). Furthermore is indicated a dimension or width 1233b of the grooves, i.e., the distance from an edge (such as the beginning of an edge, such as the end of the planar portion of the substrate outside of the groove) of a protrusion on one side of groove to an edge of a protrusion on another side of a groove as measured in a direction parallel with the plane of the first side of the substrate and orthogonal to a longitudinal direction of the grooves (i.e., measured in the horizontal and left-right direction in the plane of the paper of the figure). The dimension or width 1233b may be at least 1 micrometre, such as at least 2 micrometre, such as at least 5 micrometre, such as at least 10 micrometre, such as at least 30 micrometre, such as at least 100 micrometre, such as at least 200 pm. The dimension or width 1233b may be at most 1 mm, such as at most 500 pm, such as at most 200 pm, such as at most 100 pm. The dimension or width 1233b may be within 1 micrometer-1 mm, such as within 10 pm-500 pm. There is in Fig. 13 furthermore indicated a distance 1233c between adjacent grooves which is measured in the same direction as the width 1233b. The distance 1233c may be at least 100 pm. The distance 1233c may be at most 2 mm. The distance 1233c may be within ]100 pm; 2 mm[, such as within ]200 pm; 1 mm[.

[0213] The layer of superconducting material 1238 is comprising a high-temperature superconductor stack, so that for each groove within the plurality of grooves a first part of the coating on a first side of the groove is physically disconnected, from a second part of the coating on a second side of the groove, wherein the second side of the feature of the groove is opposite of the first side of the feature of the groove.

[0214] By 'a layer of superconducting material' may be understood a layer comprising the superconducting material itself, and which may optionally include adjacent or functionally associated layers such as buffers or capping layers, e.g., forming part of a superconducting functional stack. The layer of superconducting material may in embodiments consist of superconducting material.

[0215] By a 'superconductor stack', such as 'a high-temperature superconductor stack' may be understood a structure, optionally a multilayered structure, comprising superconducting material, optionally along with other materials, such as layers, such as buffer layers, substrates, or other supporting structures. A superconductor stack may thus comprise a superconducting material, such as a superconducting material layer, and other materials, such as may consist of superconducting material.

[0216] FIG. 14 shows a method step of providing an intermediate layer by depositing intermediate layer material 1240 in a line-of-sight process as illustrated via the straight arrows 1242.

[0217] FIG. 15 shows the substrate with the intermediate layer 1244, wherein parts of the intermediate layer are coherently bound to each other, albeit via thinner parts at the edges of the grooves connecting to other parts in the grooves.

[0218] FIG. 16 shows a method step of providing an opposite layer by depositing opposite layer material 1252 in a non-line-of-sight process as illustrated via the multiple-directional straight arrows 1254.

[0219] FIG. 17 shows the substrate with the opposite layer 1256.

[0220] FIG. 18 shows the superconducting tape 1800 after forming an alloy layer 1258 by alloying the intermediate layer 1244 and the opposite layer 1256 at their interface. The figure also shows that remaining portions of the intermediate layer form a plurality of intermediate objects 1260 arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other. In the present embodiment, the alloying step was kept running until all the opposite layer 1256 was consumed.

[0221] FIG. 19 shows an alternative step the superconducting tape 1900, such as an alternative step in a method for producing a superconducting tape according to the second aspect of the invention, wherein the substrate has been removed. In another alternative, both opposite layer and substrate is removed.

[0222] FIG. 20 shows the superconducting tape 2000 which furthermore comprises an encircling coating 1264, such as said encircling coating comprising Cu or Sn, such as wherein the encircling coating comprises Sn added in the same step as the step of providing the opposite layer (e.g., in a non-directional process providing encircling opposite layer material, thereby forming both the opposite layer and the encircling coating in one step).

[0223] FIG. 21 shows the superconducting tape 2100 wherein the encircling coating 1264 of FIG. 20 has been treated, such as in an oxidation step, to convert a part of the encircling coating 1264 into an outer encircling coating 1268, such as said outer encircling coating comprising Sn oxide or Sn carbide, wherein the outer encircling coating is electrically non-conducting, and leaving an inner part 1266 unaffected. In an alternative embodiment, all of the original outer coating 1264 is converted into an electrically non-conducting outer coating. In another embodiment, the outer coating 1264 is electrically non-conducting (which may dispense with a need for the conversion step).

[0224] EXAMPLE 1

[0225] According to an embodiment, there is presented a method of forming a superconducting tape, said method comprising :

[0226] Step 1 : Start with a polished 4 mm wide, 100 pm thick and 50 m long Hastelloy tape with surface roughness below 10 nm (where surface roughness is arithmetic surface roughness value over a 10x10 pm2atomic force microscopy scan). The surface quality is suitable for coated conductor (CC) chemical vapor deposition (CVD) / metal organic chemical vapor deposition (MOCVD), physical vapor deposition (PVD) or chemical deposition of buffer layers and superconducting layer. Polishing can be achieved by electrochemical polishing in a solution of phosphorus and sulfuric acid mixture following standard procedures from the literature, see, e.g., Wulff et al. 2015, Supercond. Sci. TechnoL 28 (2015) 072001, page 2, section 2.

[0227] Step 2: Apply a masking material as described in Wulff et al. 2015, Supercond. Sci. TechnoL 28 (2015) 072001, page 2, section 2. This could be a masking tape, such as a film of poly(4,4'-oxydiphenylene- pyromellitimide, such as a Kapton® film, a photoresist or similar. It is understood that 'Kapton® film' refers to the well-known product from DuPont™ which is a film of poly(4,4'-oxydiphenylene- pyromellitimide).

[0228] Step 3: Remove part of the masking material using mechanical scribing, a wet / dry chemical lithography process, or by laser scribing. Here it is done using standard lithography steps to fully remove the masking material in areas where grooves are to be etched. Step 4: Etch into the substrate using a mixture of phosphorus and sulfuric acid applying a current density between 0.01-1 A / cm2until grooves have been formed.

[0229] Step 5: Remove the masking material using an organic solvent (such as acetone) or a stripping agent such as sodium hydroxide.

[0230] Step 6: Deposit a superconducting coated conductor (CC) stack on the material, cf., e.g., a method as described in Wulff et al 2015, Supercond. Sci. TechnoL 28 (2015) 072001, page 2, section 2, or Insinga et al 2018, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 28, NO. 4, JUNE 2018, page 2, section 2.

[0231] Deposition methods may include pulsed laser deposition (PLD), double disordered REBCO layer by PLD (DD-PLD) reactive co-evaporation by deposition and reaction (RCE-DR), metalorganic chemical vapor deposition (MOCVD) and electron-beam physical vapor deposition (EB-PVD).

[0232] Step 7: Deposit a protective Ag coating of 1-2 pm in thickness using PVD such as thermal evaporation, sputtering or e-beam assisted deposition.

[0233] Step 8: Deposit a copper layer of thickness 3-20 pm, such as 5-20 pm, using PVD to allow for line-of-sight deposition of said copper layer.

[0234] Step 9: Electroplate a layer of 5-10 pm thickness Sn using a solution based on methane sulfonic acid (MSA). Solution example 225 g / L MSA, 45 g / L Sn. Operation temperature = 40° C and current density = 20 mA / cm2for 5-10 min.

[0235] Step 10: Alloying by, e.g., a thermal treatment, such as 200 degrees Celsius for 4 hours.

[0236] Process flow - example 2

[0237] Repeat process steps 1-8 as described in example 1.

[0238] Step 9: Electroplate a 1-2 pm Cu layer in a cathodic setup. Solution example 24 g CuSO4, 6 g H2SO4, HCI 25 pL and 100 mL ion-free water. Operation temperature = 20° C and current density = 83 mA / cm2for 1-10 min.

[0239] Step 10: Rinse the coated tape with water. Step 11 : Electroplate a layer of 5-10 pm thickness Sn using a solution based on methane sulfonic acid (MSA). Solution example 225 g / L MSA, 45 g / L Sn. Operation temperature = 40° C and current density = 20 mA / cm2for 5-10 min.

[0240] Process flow - example 3

[0241] As example 2 wherein an alloying step was carried out in the form of step 11, i.e., the alloying step was realized, such as solely realized, by step 11.

[0242] FIG. 22 shows a SEM micrograph an embodiment, such as corresponding to an embodiment being the result of process flow according to example 3 above, of a superconducting tape 2200 with a 1.1 pm alloy layer 2258 comprising bronze (the alloy layer comprises CueSns and CusSn) and being formed between a 3.8 pm intermediate layer 2244 comprising, such as substantially consisting of Cu (which was electroplated), and a 11.7 pm opposite layer 2256 comprising, such as substantially consisting of, Sn. The figure also shows a Hastelloy substrate 2230, a 3.5 pm MgO buffer layer 2262, a 3.5 pm REBCO superconducting element 2238, and a 1.9 pm Ag layer 2264. The dimensions referred to above are in each case the thickness, i.e., the dimension in the plane of the paper being orthogonal to the surface of the respective layer, such as in an up-down direction in the right-hand side of the figure. The figure is isometric. A distance between the Hastelloy substrate 2230 and the superconducting element 2238, which is given by superconducting material in the form of REBCO, is approximately equal to or less than a thickness of the MgO buffer layer 2262, i.e., approximately 3.5 pm or less.

[0243] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.

[0244] CLAUSES

[0245] There is furthermore presented a method for producing a superconducting tape, a superconducting tape and a use of a superconducting according to the clauses below, which clauses may be combined with any of the preceding embodiments and / or any of the appended claims:

[0246] 1. A method (100) for producing a superconducting tape, said method comprising, optionally sequentially: a. Providing a substrate (102), b. Providing a plurality of superconducting elements on the substrate (104), each of said superconducting elements being an elongated superconducting element, each of said superconducting elements optionally being on the same side of the substrate, and said plurality of superconducting elements being arranged to be substantially parallel, such as parallel, c. Providing an intermediate layer (106), said intermediate layer comprising, such as consisting of, a metal, and said intermediate layer being arranged at least partially, such as partially or fully, such as fully, on the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element, d. Providing an opposite layer (108) adjoining the intermediate layer on the opposite side of the intermediate layer with respect to the superconducting elements, said opposite layer optionally comprising, such as consisting of, a metal, wherein a composition of the opposite layer is different with respect to a composition of the intermediate layer, and e. Forming an alloy layer (110) by alloying the intermediate layer and the opposite layer at their interface.

[0247] 2. A method according to clause 1, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer:

[0248] Remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other. A method according to any of the preceding clauses, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, an average electrical resistance of a remaining portion of the intermediate layer is smaller, such as with respect to a situation prior to forming, such as immediately prior to, the alloy layer, for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 100 % smaller, such as at least 1000 % smaller. A method according to any of the preceding clauses, wherein during the step of forming the alloy layer, one or more sections of the intermediate layer become part of the alloy layer, so that gaps in the intermediate layer appear and / or increase in size, optionally so that a. remaining portions of the intermediate layer subsequent to forming the alloy layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other. A method according to any of the preceding clauses, wherein a ratio between a. an average electrical resistance of a remaining portion of the intermediate layer for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, and b. an average electrical resistance of a remaining portion of the intermediate layer for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, decreases during the step of forming the alloy layer, such as decreases by at least 1 %, such as decreases by at least 2 %, such as decreases by at least 5 %, such as decreases by at least 10 %, such as decreases by at least 50 %, such as decreases by at least 100 %, such as decreases by at least 1000 %. A method according to any of the preceding clauses, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, a resistance from one superconducting element to a neighbouring superconducting element increases, such as with respect to a situation prior to, such as immediately prior to, forming the alloy layer, such as increases by at least 1 %, such as at least 2 %, such as at least 5 %, such as at least 10 %, such as at least 50 %, such as at least 100 %, such as at least 1000 %. A method according to any of the preceding clauses, wherein the alloying, such as the alloying process, is stopped (112) at a time when remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other, and / or when an average electrical resistance of a remaining portion of the intermediate layer is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 100 % smaller, such as at least 1000 % smaller. perconducting tape (200, 1500, 1700) comprising: a. A substrate (230), b. An alloy layer (258), c. A plurality of superconducting elements (238), each of said superconducting elements being an elongated superconducting element, and said plurality of superconducting elements being substantially parallel, such as parallel, and placed on the substrate and between the substrate and the alloy layer, and d. One or more intermediate objects (260), said one or more intermediate objects comprising, such as consisting of, a metal, and said one or more intermediate objects being arranged so that between each superconducting element and the alloy layer, there is a portion of the one or more intermediate objects, which portion is adjoining the alloy layer, wherein the alloy layer comprises, such as consists of, an alloy of at least the material of the intermediate objects.

[0249] 9. The superconducting tape (200, 1500, 1700) according to clause 8, wherein the one or more intermediate objects (260) form a plurality of intermediate objects (260) arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

[0250] 10. The superconducting tape (200, 1500, 1700) according to any of clauses 8-9, wherein an average electrical resistance of the one or more intermediate objects (260) is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 100 % smaller, such as at least 1000 % smaller.

[0251] 11. The superconducting tape (200, 1500, 1700) according to any of clauses 8-10, wherein the one or more intermediate objects (260) are absent or comprising a thickness at one or more points between the neighbouring portions which is smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, compared to a thickness at the portions, such as wherein thickness is to be measured in a direction orthogonal to a longitudinal direction of the superconducting elements at one or both neighbouring portions and in a direction being normal to a surface of the one or more intermediate objects, such as the surface facing the superconducting elements. The superconducting tape (200, 1500, 1700) according to any of clauses 8-11, wherein the substrate comprises undercut sections (236), such as located adjacent to edges of the superconducting elements. The superconducting tape (200, 1500, 1700) according to any of clauses 8-12, wherein a length, such as a maximum dimension in a longitudinal direction of the tape, is equal to or larger than 1 m, such as equal to or larger than 10 m, such as equal to or larger than 100 m, such as equal to or larger than 1 km, such as equal to or larger than 10 km, such as equal to or larger than 100 km, such as equal to or larger than 1000 km. The superconducting tape (200, 1500, 1700) according to any of clauses 8-13, wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm. Use of a superconducting tape (200, 1500, 1700) as prepared by a method according to any of clauses 1-7 or the superconducting tape according to any of clauses 8-14, for carrying an electrical current, such as at least 1 mA, such as at least 10 mA, such as at least 100 mA, such as at least 1 A, such as at least 10 A, such as at least 100 A, such as at least 1 kA.

Claims

Claims1. A method (100) for producing a superconducting tape, said method comprising, optionally sequentially:• Providing a substrate (102),• Providing a plurality of superconducting elements on the substrate (104), each of said superconducting elements being an elongated superconducting element, each of said superconducting elements optionally being on the same side of the substrate, and said plurality of superconducting elements being arranged to be substantially parallel, such as parallel,• Providing an intermediate layer (106), said intermediate layer comprising, such as consisting of, a metal, and said intermediate layer being arranged at least partially, such as partially or fully, such as fully, on the opposite side of the plurality of superconducting elements with respect to the substrate, and so that for each superconducting element, a part of the intermediate layer is placed on the superconducting element,• Providing an opposite layer (108) adjoining the intermediate layer on the opposite side of the intermediate layer with respect to the superconducting elements, said opposite layer optionally comprising, such as consisting of, a metal, wherein a composition of the opposite layer is different with respect to a composition of the intermediate layer, and• Forming an alloy layer (110) by alloying the intermediate layer and the opposite layer at their interface.

2. A method according to claim 1, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer:Remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

3. A method according to any of the preceding claims, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, an average electrical resistance,such as an electrical resistance per unit length, of a remaining portion of the intermediate layer is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as at least 100 % smaller.

4. A method according to any of the preceding claims, wherein during the step of forming the alloy layer, one or more sections of the intermediate layer become part of the alloy layer, so that gaps in the intermediate layer appear and / or increase in size, optionally so that• remaining portions of the intermediate layer subsequent to forming the alloy layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

5. A method according to any of the preceding claims, wherein a ratio between• an average electrical resistance, such as an electrical resistance per unit length, of a remaining portion of the intermediate layer for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element,to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, and• an average electrical resistance, such as an electrical resistance per unit length, of a remaining portion of the intermediate layer for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, decreases during the step of forming the alloy layer, such as decreases by at least 1 %, such as decreases by at least 2 %, such as decreases by at least 5 %, such as decreases by at least 10 %, such as decreases by at least 50 %, such as decreases by at least 75 %, such as decreases by at least 90 %, such as decreases by at least 95 %, such as decreases by at least 100 %.

6. A method according to any of the preceding claims, wherein the forming of an alloy layer is carried out so that subsequent to forming the alloy layer, an electrical resistance from one superconducting element to a neighbouring superconducting element increases with respect to a situation prior to, such as immediately prior to, forming the alloy layer, such as increases by at least 1 %, such as at least 2 %, such as at least 5 %, such as at least 10 %, such as at least 50 %, such as at least 100 %, such as at least 1000 %.

7. A method according to any of the preceding claims, wherein the alloying, such as the alloying process, is stopped (112) at a time when remaining portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other, and / or whenan average electrical resistance, such as an electrical resistance per unit length, of a remaining portion of the intermediate layer is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as 100 % smaller.

8. A method according to any of claims 3, 5, and / or 7, wherein:• The average electrical resistance is the electrical resistance per unit length,• The first point and the second point are chosen to be as distant with respect to each other as possible,• The third point and the fourth point are chosen to be as close to each other as possible,• The first point, the second point and the third point are each chosen to be as close as possible to the superconducting element, such as adjoining the superconducting element, and• The fourth point is chosen to be as close as possible to the neighbouring superconducting element, such as adjoining the neighbouring superconducting element.

9. A method according to any of the preceding claims, wherein producing the superconducting tape, such as including the forming of an alloy layer, is carried out so that a temperature of the plurality of superconducting elements does not exceed 200° C, such as does not exceed 175°C, such as does not exceed 150 °C, such as does not exceed 125° C such as does not exceed 100° C, such as does not exceed 75°C, such as does not exceed 50 °C, such as does not exceed 40° C.

10. A method according to any of the preceding claims, wherein providing the intermediate layer comprises plating, such as electroplating and / or wherein providing the opposite layer comprises plating, such as electroplating.

11. A method according to any of the preceding claims, wherein the intermediate layer comprises copper (Cu), wherein the opposite layer comprises tin (Sn), and wherein the alloy layer comprises an alloy of the element pair Cu-Sn, such as bronze.

12. A superconducting tape (200, 1500, 1700) comprising:• A substrate (230),• An alloy layer (258),• A plurality of superconducting elements (238), each of said superconducting elements being an elongated superconducting element, and said plurality of superconducting elements being substantially parallel, such as parallel, and placed on the substrate, such as wherein each of said superconducting elements are being on the same side of the substrate, and between the substrate and the alloy layer, and• One or more intermediate objects (260), said one or more intermediate objects comprising, such as consisting of, a metal, and said one or more intermediate objects being arranged so that between each superconducting element and the alloy layer, there is a portion of the one or more intermediate objects, which portion is adjoining the alloy layer, wherein the alloy layer comprises, such as consists of, an alloy of at least the material of the one or more intermediate objects.

13. The superconducting tape (200, 1500, 1700) according to claim 12, wherein the one or more intermediate objects (260) form a plurality of intermediate objects (260) arranged so that between each superconducting element and the alloy layer, there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer, and wherein said intermediate objects are spatially separated from each other.

14. The superconducting tape (200, 1500, 1700) according to any of claims 12-13, wherein an average electrical resistance, such as an electrical resistance per unit length, of the one or more intermediate objects (260) is smaller for a current passing in a cross-sectional plane orthogonal to a longitudinal direction of a superconducting element from o a first point adjacent to, such as adjoining, the superconducting element, to o a second point adjacent to, such as adjoining, the superconducting element, said second point being spatially separated with respect to the first point, than from o a third point adjacent to, such as adjoining, the superconducting element, to o a fourth point adjacent to, such as adjoining, a neighbouring superconducting element, such as at least 1 % smaller, such as at least 2 % smaller, such as at least 5 % smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, such as at least 95 % smaller, such as 100 % smaller.

15. The superconducting tape (200, 1500, 1700) according to any of claims 12-14, wherein the one or more intermediate objects (260) are absent, such as absent at one or more points between neighbouring portions and / or such as wherein portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer and wherein said intermediate objects are spatially separated from each other, or comprising a thickness at one or more points between neighbouring portions, such as between the neighbouring portions, which is smaller, such as at least 10 % smaller, such as at least 50 %smaller, such as at least 75 % smaller, such as at least 90 % smaller, compared to a thickness at the portions, such as wherein thickness is to be measured in a direction orthogonal to a longitudinal direction of the superconducting elements at one or both neighbouring portions and in a direction being normal to a surface of the one or more intermediate objects, such as the surface facing the superconducting elements.

16. The superconducting tape (200, 1500, 1700) according to any of claims 12-15, wherein the substrate comprises undercut sections (236), such as located adjacent to edges of the superconducting elements.

17. The superconducting tape (200, 1500, 1700) according to any of claims 12-16, wherein a length, such as a maximum dimension in a longitudinal direction of the tape, is equal to or larger than 1 m, such as equal to or larger than 10 m, such as equal to or larger than 100 m, such as equal to or larger than 1 km, such as equal to or larger than 10 km, such as equal to or larger than 100 km, such as equal to or larger than 1000 km.

18. The superconducting tape (200, 1500, 1700) according to any of claims 12-17, wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm.

19. The superconducting tape (200, 1500, 1700) according to any of claims 12-18, wherein each of said superconducting elements are being on the same side of the substrate.

20. The superconducting tape (200, 1500, 1700) according to claim 14, wherein:• The average electrical resistance is the electrical resistance per unit length,• The first point and the second point are chosen to be as distant with respect to each other as possible,• The third point and the fourth point are chosen to be as close to each other as possible,• The first point, the second point and the third point are each chosen to be as close as possible to the superconducting element, such as adjoining the superconducting element, andThe fourth point is chosen to be as close as possible to the neighbouring superconducting element, such as adjoining the neighbouring superconducting element.

21. The superconducting tape (200, 1500, 1700) according to any of claims 12-20,• wherein portions of the intermediate layer form a plurality of intermediate objects arranged so that between each superconducting element and the alloy layer there is an intermediate object comprising the part of the intermediate layer placed on the superconducting element and adjoining the alloy layer and wherein said intermediate objects are spatially separated from each other, and / or• wherein portions of the intermediate layer have a thickness at one or more points between neighbouring portions, such as neighbouring portions positioned between each superconducting element and the alloy layer, which is smaller, such as at least 10 % smaller, such as at least 50 % smaller, such as at least 75 % smaller, such as at least 90 % smaller, compared to a thickness at the neighbouring portions, such as wherein thickness is to be measured in a direction orthogonal to a longitudinal direction of the superconducting elements at one or both neighbouring portions and in a direction being normal to a surface of the one or more intermediate objects, such as the surface facing the superconducting elements.

22. The superconducting tape (200, 1500, 1700) according to any of claims 12-21, wherein the superconducting tape is the result of a production, such as a production process, according to any of claims 1-11.

23. The superconducting tape (200, 1500, 1700) according to any of claims 12-22, wherein the superconducting tape is the result of a production, such as a production process,• which is carried out so that a temperature of the plurality of superconducting elements does not exceed 200° C, such as does not exceed 175°C, such as does not exceed 150 °C, such as does not exceed 125° C such as does not exceed 100° C, such as does not exceed 75°C, such as does not exceed 50 °C, such as does not exceed 40° C, and / or• wherein providing the intermediate layer comprises plating, such as electroplating.

24. The superconducting tape (200, 1500, 1700) according to any of claims 12-23, wherein each of said superconducting elements comprises a superconducting material, and wherein a minimum distance from the superconducting material of each superconducting element to the substrate is equal to 10 pm or less, such as 8 pm or less, such as 6 pm or less, such as 5 pm or less, such as 4 pm or less, such as 3 pm or less, such as 2 pm or less, such as 1 pm or less.

25. The superconducting tape (200, 1500, 1700) according to any of claims 12-24, wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, wherein each of said superconducting elements comprises a superconducting material, and wherein a minimum distance from the superconducting material of each superconducting element to the substrate is equal to 10 pm or less, such as 8 pm or less, such as 6 pm or less, such as 5 pm or less, such as 4 pm or less, such as 3 pm or less, such as 2 pm or less, such as 1 pm or less.

26. The superconducting tape (200, 1500, 1700) according to any of claims 12-25, wherein the substrate comprises an alloy, such as metallic alloy comprising at least 10.5 wt% chromium and less than 1.2 wt% carbon, and optionally comprising nickel, such as said alloy being chosen from a group comprising, such as consisting of, Hastelloy® stainless steel and / or Inconel®.

27. The superconducting tape (200, 1500, 1700) according to any of claims 12-26,• wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, and• wherein the substrate comprises an alloy, such as metallic alloy comprising at least 10.5 wt% chromium and less than 1.2 wt% carbon, and optionally comprising nickel, such as said alloy being chosen from a group comprising, such as consisting of, Hastelloy®, stainless steel and / or Inconel®.

28. The superconducting tape (200, 1500, 1700) according to any of claims 12-27, wherein each of said superconducting elements comprises, such as consists of, rare-earth barium copper oxide.

29. The superconducting tape (200, 1500, 1700) according to any of claims 12-28, wherein the intermediate layer comprises copper (Cu), and wherein the alloy layer comprises an alloy of the element pair Cu-Sn, such as bronze.

30. The superconducting tape (200, 1500, 1700) according to any of claims 12-29, wherein the substrate is non-planar, and / or has grooves.

31. The superconducting tape (200, 1500, 1700) according to any of claims 12-30, wherein the substrate has grooves.

32. The superconducting tape (200, 1500, 1700) according to any of claims 12-31,• wherein a thickness of the alloy layer is at least 100 nm, such as at least 200 nm, such as at least 500 nm, such as at least 1 pm, and• wherein the substrate is non-planar and / or has grooves.

33. The superconducting tape (200, 1500, 1700) according to any of claims 12-32, wherein the substrate is non-planar such that for one or more pairs of neighbouring superconducting elements, such as nearest neighbouring superconducting elements, in at least one cross- sectional plane orthogonal to a longitudinal direction of one or both of the superconducting elements in the pair of neighbouring superconducting elements, a straight line can be drawn from• a primary point in the substrate, wherein the primary point in the substrate is the point in the substrate closest to the superconducting element on the opposite side of the superconducting element with respect to the intermediate layer and the alloy layer and on a rectilinear path traversing a geometrical center of the superconducting element and being orthogonal to another rectilinear path intersecting the two points in the superconducting element being farthest apart, and• a secondary point in the substrate, wherein the secondary point in the substrate is the point in the substrate closest to the other one of the superconducting elements in the pair of neighbouring superconducting elements on the opposite side of the other one of the superconducting elements in the pair of neighbouring superconducting elements with respect to the intermediate layer and the alloy layer and on a rectilinear path traversing a geometrical center of the other one of thesuperconducting elements in the pair of neighbouring superconducting elements and being orthogonal to another rectilinear path intersecting the two points in the other one of the superconducting elements in the pair of neighbouring superconducting elements being farthest apart, and wherein the primary point and the secondary point are on the same side of a rectilinear path intersecting the geometrical centers of the superconducting element and the other one of the superconducting elements in the pair of neighbouring superconducting elements, and wherein there is one or more points on said straight line along said straight line between the primary point and the secondary point, wherein a minimum distance from the one or more points on said line to the substrate, such as to the surface of the substrate,• is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm,• is optionally at most 4 mm, such as at most 2 mm, such as at most 1 mm,• such as is within ]10 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm; 1 mm[.

34. The superconducting tape (200, 1500, 1700) according to any of claims 12-33, wherein the substrate has grooves and wherein• a distance 233a, such as a first distance and / or a depth of the grooves, between i. a plane being parallel with a surface of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, such as being tangential with the protrusions between the grooves 234, and ii. a plane being tangential to the bottom of the plurality of grooves, as measured in a direction orthogonal to the plane of the first side of the substrate is non-zero, such as at least 100 nm, such as at least 1 pm, such as at least 10 pm, such as at least 25 pm, such as at least 50 pm, such as at least 100 pm, and• The distance 233a, such as a first distance and / or a depth of the grooves, is optionally within ]100 nm; 4 mm[, such as within ]1 pm; 2 mm[, such as within ]10 pm; 1 mm[.

35. The superconducting tape (200, 1500, 1700) according to any of claims 12-34, wherein the substrate has grooves and wherein• a distance 233b, such as a second distance and / or a width of the grooves, from i. an edge, such as the beginning of an edge, such as the end of the planar portion of the substrate outside of the groove, of a protrusion on one side of groove, to ii. an edge of a protrusion on another side of a groove as measured in a direction parallel with the plane of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, and orthogonal to a longitudinal direction of the grooves is at least 1 micrometres, such as at least 2 micrometres, such as at least 5 micrometres, such as at least 10 micrometres, such as at least 30 micrometres, such as at least 100 micrometres, such as at least 200 pm,• the distance 233b, such as a second distance and / or a width of the grooves, is at most 1 mm, such as at most 500 pm, such as at most 200 pm, such as at most 100 pm, and / or• the distance 233b, such as a second distance and / or a width of the grooves, is within 1 micrometer-1 mm, such as within 10 pm-500 pm.

36. The superconducting tape (200, 1500, 1700) according to any of claims 12-35, wherein the substrate has grooves and wherein• a distance 233c, such as a third distance, between adjacent grooves measured in a direction parallel with the plane of a first side of the substrate, such as the first side of the substrate facing the plurality of superconducting elements, and orthogonal to a longitudinal direction of the grooves is at least 100 pm and / or at most 2 mm, such as wherein the distance, such as the third distance, 233c is within ]100 pm; 2 mm[, such as within ]200 pm; 1 mm[.

37. Use of a superconducting tape (200, 1500, 1700) as prepared by a method according to any of claims 1-11 or the superconducting tape according to any of claims 12-36, for carrying an electrical current, such as at least 1 mA, such as at least 10 mA, such as at least 100 mA, such as at least 1 A, such as at least 10 A, such as at least 100 A, such as at least 1 kA.

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