Superconductor manufacturing method

Abstract

There is provided a method for manufacturing a current flow diverter (CFD) for a superconducting segment. The method comprises depositing at least one pattern of stabilizer material on a portion of an outer surface of a superconducting layer of the superconducting segment and creating a first interfacial resistive layer on the outer surface, adjacent the stabilizer pattern, annealing, subsequent to depositing the stabilizer pattern, the superconducting segment in an oxygen atmosphere and creating a second interfacial resistive layer between the stabilizer pattern and the outer surface, the second interfacial resistive layer having an electrical resistance lower than that of the first interfacial resistive layer, and depositing, subsequent to annealing the superconducting segment, a stabilizer layer over at least the outer surface and creating at least one path for diverting, via the first and second interfacial resistive layers, a flow of electrical current from the superconducting layer to the stabilizer layer.

Description

SUPERCONDUCTOR MANUFACTURING METHODCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of Unites States Provisional Application No. 63 / 570,965 filed on March 28, 2024, the contents of which are hereby incorporated by reference.FIELD

[0002] The improvements generally relate to the field of superconductors, and more particularly to a method for manufacturing superconductors.BACKGROUND

[0003] Superconductors are materials that conduct electricity without resistance, when i) they are cooled below a temperature referred to as the critical temperature (Tc), ii) a magnetic field applied to the superconductor is less than a magnetic field referred to as the critical field (Bc), and iii) the current density in the superconductor is less than a current density referred to as the critical current density (Jc). Superconductors are used in applications such as electromagnets, fault current limiters (FCLs), motors, etc. The advantages of using superconductors over conventional conductors, such as copper or aluminum, are weight reduction, compactness, production of higher magnetic field (electromagnets), increased protection level and reliability of supply in power systems (FCLs), etc. Some applications, such as resistive superconducting FCLs, which aim to protect electrical equipment in the electrical grid, are based on the “quench” of the superconductor. Quench is the transition from the superconducting state to the normal state by heat generation when the superconductor’s temperature T rises above Tc. If a fault occurs in the grid, the line current increases to several times the nominal value and the current density in the superconductor exceeds Jc. The superconductor then becomes resistive and the energy dissipation raises its temperature T. When the superconductor’s temperature T reaches Tc, the superconductor becomes normal and its resistivity becomes very high, even compared with that of normal metals like copper (Cu) or silver (Ag). To the electrical network, this is seen as a sudden insertion of high impedance in series with the source, which reduces the line current and enables the device to protect expensive electrical equipment downstream. Others superconducting applications, such as electromagnets, motors, etc. can experience quench phenomena. In case of a quench,it is imperative to stop the current in a rapid manner to prevent damage to the superconducting device.

[0004] Rare-earth barium copper oxide (REBCO) coated conductors have gained interest in designing high-field applications, especially future fusion magnets. While REBCO tapes have the capacity to generate an intense magnetic field, have a high critical temperature and high critical current density, quench protection remains a challenge. Several quench protection techniques have been studied using acoustic thermometry, hall sensors, optical fibers, radio frequency waves, and voltage taps. A critical parameter of the quench behavior of high-temperature superconductor (HTS) tapes has been found to be the normal zone propagation velocity (NZPV). However, NZPV is low in HTS tapes, which can delay quench detection and lead to damage.

[0005] Therefore, there is a need for improvement.SUMMARY

[0006] In accordance with one aspect, there is provided a method for manufacturing a current flow diverter (CFD) for a superconducting segment. The method comprises depositing at least one pattern of a stabilizer material on a portion of an outer surface of a superconducting layer of the superconducting segment and creating a first interfacial resistive layer on the outer surface of the superconducting layer, adjacent the at least one pattern of the stabilizer material, annealing, subsequent to depositing the at least one pattern of the stabilizer material, the superconducting segment in an oxygen atmosphere and creating a second interfacial resistive layer between the at least one pattern of the stabilizer material and the outer surface of the superconducting layer, the second interfacial resistive layer having an electrical resistance lower than that of the first interfacial resistive layer, and depositing, subsequent to annealing the superconducting segment, a layer of the stabilizer material over at least the outer surface of the superconducting layer having the at least one pattern of the stabilizer material deposited thereon and creating at least one path for diverting, via the first and second interfacial resistive layers, a flow of electrical current from the superconducting layer to the layer of the stabilizer material.

[0007] In at least one embodiment in accordance with any previous / other embodiment described herein, the superconducting segment is a layered structure having a top surfaceformed by the outer surface of the superconducting layer, a bottom surface, and opposite side surfaces, and prior to the depositing the at least one pattern of the stabilizer material, the outer surface of the superconducting layer is free of the stabilizer material while the bottom and side surfaces of the superconducting segment have the stabilizer material deposited thereon.

[0008] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the layer of the stabilizer material comprises depositing the layer of the stabilizer material only on the outer surface of the superconducting layer.

[0009] In at least one embodiment in accordance with any previous / other embodiment described herein, the superconducting segment is a layered structure having a top surface formed by the outer surface of the superconducting layer, a bottom surface, and opposite side surfaces, and prior to the depositing the at least one pattern of the stabilizer material, the outer surface of the superconducting layer and the bottom and side surfaces of the superconducting segment are free of the stabilizer material.

[0010] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the layer of the stabilizer material comprises depositing the layer of the stabilizer material on the bottom and side surfaces of the superconducting segment in addition to the outer surface of the superconducting layer.

[0011] In at least one embodiment in accordance with any previous / other embodiment described herein, the layer of the stabilizer material is deposited on the outer surface of the superconducting layer over the at least one pattern of the stabilizer material.

[0012] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along one or more lines.

[0013] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along a central axis of the superconducting segment.

[0014] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along a first straight line and a second straight line parallel to the first line, the first line deposited along a first lateral edge of the superconducting layer and the second line is deposited along a second lateral edge of the superconducting layer opposite to the first edge.

[0015] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material in a geometrical pattern.

[0016] In at least one embodiment in accordance with any previous / other embodiment described herein, the geometrical pattern is symmetrical about a central axis of the superconducting segment.

[0017] In at least one embodiment in accordance with any previous / other embodiment described herein, the at least one pattern of the stabilizer material is deposited using one of inkjet printing, screen printing, and flexography.

[0018] In at least one embodiment in accordance with any previous / other embodiment described herein, the at least one pattern of the stabilizer material is deposited using one of evaporation, magnetron sputtering, molecular beam epitaxy, and electrodeposition.

[0019] In at least one embodiment in accordance with any previous / other embodiment described herein, depositing the at least one pattern of the stabilizer material comprises positioning a shadow mask on the outer surface of the superconducting layer, the shadow mask partially covering the outer surface to create at least one masked region and at least one unmasked region, depositing the stabilizer material on the at least one masked region and the at least one unmasked region of the outer surface of the superconducting layer, and removing the shadow mask to expose the at least one pattern of the stabilizer material formed on the outer surface of the superconducting layer.

[0020] In at least one embodiment in accordance with any previous / other embodiment described herein, the shadow mask has formed therein at least one aperture defining the at least one unmasked region of the superconducting layer, the stabilizer materialdeposited on the outer surface of the superconducting layer through the at least one aperture.

[0021] In at least one embodiment in accordance with any previous / other embodiment described herein, the at least one aperture is an elongated slot centered relative to lateral edges of the shadow mask, and positioning the shadow mask on the outer surface of the superconducting layer comprises aligning the slot with a central axis of the superconducting segment for depositing the stabilizer material along the central axis.

[0022] In at least one embodiment in accordance with any previous / other embodiment described herein, the layer of the stabilizer material is deposited by sputtering.

[0023] In at least one embodiment in accordance with any previous / other embodiment described herein, the stabilizer material comprises silver.

[0024] In at least one embodiment in accordance with any previous / other embodiment described herein, the superconducting layer comprises Rare-earth barium copper oxide (REBCO).

[0025] Many further features and combinations thereof concerning embodiments described herein will appear to those skilled in the art following a reading of the instant disclosure.DESCRIPTION OF THE FIGURES

[0026] In the figures,

[0027] Fig. 1 is a flowchart of a manufacturing method of the metallic, semiconducting, and insulating layers surrounding a superconducting stack, in accordance with one embodiment;

[0028] Fig. 2A is a schematic diagram of the step 102 of Fig. 1 of depositing stabilizer pattern(s) on the outer surface of the superconducting layer of a superconducting segment, in accordance with one embodiment;

[0029] Fig. 2B is a schematic diagram of the step 104 of Fig. 1 of annealing the superconducting segment of Fig. 2A in the oxygen atmosphere, in accordance with one embodiment;

[0030] Fig. 2C is a schematic diagram ofthe step 106 of Fig. 1 of depositing a stabilizer layerto cover at least the outer surface of the superconducting layer of Fig. 2B having the stabilizer pattern(s) deposited thereon, in accordance with one embodiment;

[0031] Fig. 2D is a schematic diagram of the step 102 of Fig. 1 of depositing stabilizer pattern(s) on the outer surface ofthe superconducting layer of a superconducting segment having no surrounding stabilizer layer, in accordance with another embodiment;

[0032] Fig. 2E is a schematic diagram of the step 104 of Fig. 1 of annealing the superconducting segment of Fig. 2D in the oxygen atmosphere, in accordance with one embodiment;

[0033] Fig. 2F is a schematic diagram of the step 106 of Fig. 1 of depositing a surrounding stabilizer layer to cover all sides of the superconducting segment of Fig. 2E, in accordance with one embodiment;

[0034] Fig. 2G is a schematic diagram of the step 102 of Fig. 1 of depositing a shadow mask on a superconducting surface, in accordance with one embodiment;

[0035] Fig. 2H is a schematic diagram of the step 102 of Fig. 1 depositing a silver line on the superconducting surface of Fig. 2G, in accordance with one embodiment;

[0036] Fig. 2I is a schematic of the step 102 of Fig. 1 removing the shadow mask from the superconducting surface of Fig. 2H, in accordance with one embodiment;

[0037] Fig. 2J is a schematic diagram of the step 104 of Fig. 1 of annealing the superconducting segment of Fig. 2I in the oxygen atmosphere, in accordance with one embodiment;

[0038] Fig. 2K is a schematic diagram ofthe step 106 of Fig. 1 of depositing a stabilizer layer to cover at least the outer surface of the superconducting layer of Fig. 2J, in accordance with one embodiment;

[0039] Fig. 2L shows schematic diagrams of different shadow mask configurations applied on a superconducting surface, in accordance with one embodiment;

[0040] Fig. 3A is a cross-sectional transverse view of a layout of superconducting stack without a stabilizer layer on the superconductor’s outer surface, in accordance with one embodiment;

[0041] Fig. 3B is a cross-sectional transverse view of the layout of superconductor material of Fig. 3A following the deposition of a stabilizer pattern on the superconductor’s outer surface, in accordance with one embodiment;

[0042] Fig. 3C is a cross-sectional transverse view of the layout of superconductor material of Fig. 3B during the oxygenation step, in accordance with one embodiment;

[0043] Fig. 3D is a cross-sectional transverse view of the layout of superconductor material of Fig. 3C following the deposition of a top stabilizer layer on the superconductor’s outer surface, in accordance with one embodiment;

[0044] Fig. 3E is a cross-sectional transverse view of the superconductor material of Fig. 3D showing the flow of current from the superconductor to the stabilizer, in accordance with one embodiment;

[0045] Fig. 4A is a cross-sectional transverse view of the layout of superconductor material of Fig. 3A following the deposition of two stabilizer patterns on the superconductor’s outer surface, in accordance with one embodiment;

[0046] Fig. 4B is a cross-sectional transverse view of the layout of superconductor material of Fig. 4A during the oxygenation step, in accordance with one embodiment;

[0047] Fig. 4C is a cross-sectional transverse view of the layout of superconductor material of Fig. 4B following the deposition of a top stabilizer layer on the superconductor’s outer surface, in accordance with one embodiment;

[0048] Fig. 4D is a cross-sectional transverse view of the superconductor material of Fig. 4C showing the flow of current from the superconductor to the stabilizer, in accordance with one embodiment;

[0049] Fig. 5A is a cross-sectional transverse view of a layout of superconductor material without a surrounding stabilizer layer, in accordance with one embodiment;

[0050] Fig. 5B is a cross-sectional transverse view of the layout of superconductor material of Fig. 5A following the deposition of a stabilizer pattern on the superconductor’s outer surface, in accordance with one embodiment;

[0051] Fig. 5C is a cross-sectional transverse view of the layout of superconductor material of Fig. 5B during the oxygenation step, in accordance with one embodiment;

[0052] Fig. 5D is a cross-sectional transverse view of the layout of superconductor material of Fig. 5C following the deposition of top, bottom, and side stabilizer layers on the superconductor material, in accordance with one embodiment;

[0053] Fig. 5E is a cross-sectional transverse view of the superconductor material of Fig. 5D showing the flow of current from the superconductor to the stabilizer, in accordance with one embodiment;

[0054] Fig. 6A is a plot of normal zone propagation velocity (NZPV) results obtained for a current flow diverter (CFD) superconducting tape as illustrated in Fig. 5D and the NZPV results obtained for a regular tape, in accordance with one embodiment;

[0055] Fig. 6B is a plot of NZPV results obtained for a CFD superconducting tape as illustrated in Fig. 5D, the NZPV results obtained for a CFD tape fabricated using a known method, and the NZPV results obtained for a regular tape, in accordance with one embodiment;

[0056] Fig. 7A is a cross-sectional transverse view of the layout of superconductor material of Fig. 5A following the deposition of two stabilizer patterns on the superconductor’s outer surface, in accordance with one embodiment;

[0057] Fig. 7B is a cross-sectional transverse view of the layout of superconductor material of Fig. 7A during the oxygenation step, in accordance with one embodiment;

[0058] Fig. 7C is a cross-sectional transverse view of the layout of superconductor material of Fig. 7B following the deposition of top, bottom, and side stabilizer layers on the superconductor material, in accordance with one embodiment;

[0059] Fig. 7D is a cross-sectional transverse view of the superconductor material of Fig. 7C showing the flow of current from the superconductor to the stabilizer, in accordance with one embodiment; and

[0060] Figs. 8A, 8B, 8C, and 8D are top view of stabilizer patterns that can be deposited on the superconductor’s surface using the method of Fig. 1 , in accordance with one embodiment;

[0061] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.DETAILED DESCRIPTION

[0062] Described herein is a method for manufacturing the metallic, semiconducting, and insulating layers surrounding a superconductor, and more particularly for the current flow diverter (CFD) fabrication for superconductors. The method is applied to superconducting segments (also referred to herein as superconducting tapes or superconducting wires), which comprise a layered structure formed by a substrate layer, one or many buffer layers, and a superconducting layer. The CFD architecture is integrated into the superconducting segment to accelerate expansion of the quench and render the quench uniform. For this purpose, the proposed method relies on depositing one or more patterns of stabilizer material (e.g., silver) on the outer surface of the superconducting layer, followed by an oxygen annealing process to create a non-uniform resistance at the interface between the stabilizer layer (described further below) and the superconducting layer, along the width of the superconducting segment. In at least one embodiment, the stabilizer pattern can be deposited on the outer surface of a nonoxygenated or oxygenated superconducting layer, or on regions of the superconducting layer that have been exposed through a prior etching process of the top stabilizer layer. However, oxygen annealing is desirable to decrease the interfacial resistance between the deposited stabilizer pattern and the superconducting layer. Using the method described herein, the non-uniform resistance can be created without the integration of new chemical components to the original architecture of the superconducting segment architecture.

[0063] In particular, and as will be described further below, the CFD, which is embodied by a highly resistive layer, is located between the superconducting layer and the stabilizerlayer so as to deviate electrical current towards one or more desired paths, as will be described further below. The presence of the CFD increases the contact resistance between the superconducting layer and the stabilizer layer by reducing the contact area between the two. This results in an increase of current transfer and a more extended distribution of heat generation along the length of the superconducting segment, which in turn increases the NZPV. Also, the CFD forces the current to flow through the superconductor material along specific path(s) by creating current paths for current flow at specific locations. When the current is transiting from the superconducting layer to the stabilizer layer, the current is concentrated for a short period of time within a certain portion of the stabilizer layer. The current paths have a lower contact resistance than the contact resistance between the superconducting layer and the stabilizer layer created by the CFD. This leads to a controlled heat generation at a well-defined location that partially quenches the cross-section of the superconducting layer, bringing it into an even more resistive state, which further increases the NZPV.

[0064] Fig. 1 shows an example superconductor manufacturing method 100, and more particularly of a method for manufacturing the metallic, semiconducting, and insulating layers surrounding a superconducting stack (i.e. manufacturing the CFD architecture of a superconducting segment), in accordance with one embodiment. The method 100 may be applicable to different types of superconducting material. In some embodiments, the method 100 is applied to HTS tapes, such as rare-earth barium copper oxide (REBCO) tapes, having a generally elongate shape (with a substantially rectangular cross-section) and comprising a substantially planar top surface, a substantially planar bottom surface, and substantially planar side surfaces. It should however be understood that other superconducting segments may apply. Some exemplary materials for the superconducting segment (i.e. the superconducting layer) include, but are not limited to, (Re)BaCuO, such as YBaCuO, SmBaCuO, GdBaCuO, DyBaCuO, EuBaCuO etc. (where “Re” stands for “rare earth”). In addition, it should be understood that the method 100 described herein may be applied to numerous possible architectures of superconducting materials. One example embodiment of a superconducting segment that may be fabricated using the method 100 is described in US Patent No. 9,029,296, the entire contents of which are incorporated herein by reference.

[0065] In some embodiments, the superconducting segment to which the method 100 is applied may comprise a layer of stabilizer material (also referred to herein as a “stabilizerlayer”) which covers and at least partially surrounds (e.g., encapsulates) the layered structure formed by the substrate layer, the buffer layers, and the superconducting (e.g., REBCO) layer. In other words, in some embodiments, the surrounding stabilizer layer covers the superconducting segment’s top surface (formed by the outer surface of the superconducting layer), the bottom surface (formed by the outer surface of the substrate layer), and the side surfaces (formed by the side surfaces of the substrate layer, buffer layers, and superconducting layer).

[0066] As used herein, the term “stabilizer” refers to a material that acts as a heat sink, as well as provides an alternative current path when the superconducting segment (i.e. the superconducting layer) enters the normal state. For this purpose, the stabilizer layer has an electrical resistance which is greater than the electrical resistance of the superconducting layer when the superconducting layer is in the superconducting state and lower than the electrical resistance of the superconducting layer when the superconducting layer is in the normal state. When a quench occurs in the superconducting segment, current transits through the stabilizer layer. The stabilizer may comprise any combination of one or several materials that can be metals, semiconductors or insulators. Any suitable stabilizer material may be used (e.g., forthe stabilizer pattern(s) and the stabilizer layer) including, but not limited to, Silver (Ag), Copper (Cu), Gold (Or) or any other type of non-magnetic metal with high thermal and electrical conductivities and combined with semiconductors and / or insulators. It should also be understood that any suitable material may be used for the substrate layer including, but not limited to, superalloys or high-performance allows such as Hastelloy™, Nickel allows, and stainless steel. Any suitable material may also be used for the buffer layers including, but not limited to MgO, CeC>2, LaMnCh, AI2O3, Y2O3.

[0067] At step 102, one or more stabilizer patterns (i.e. at least one stabilizer pattern) are deposited on a portion of the outer surface of the superconducting (e.g., REBCO) layer. As will be described further below, it should be understood that step 102 may comprise depositing a single stabilizer pattern (e.g., depositing the stabilizer material along a single straight line or a single pattern) or multiple stabilizer patterns (e.g., multiple straight lines or multiple patterns) at any suitable position on the outer surface of the superconducting segment, as will be described further below. The stabilizer pattern(s) deposited at step 102 may also have any suitable dimensions (i.e. thickness and width). Any suitable technique may be used at step 102. In one embodiment, inkjet printing isused to create conductive patterns on the superconducting layer. As understood by those skilled in the art, inkjet printing relies on ejecting liquid through a microscopic orifice, namely the nozzle, to create uniform drops. In one embodiment, a piezoelectric drop-on- demand (DoD) system may be used. The DoD system relies on applying periodic voltage waves to create periodic deformations of the piezoelectric material. These deformations result in expelling drops from the nozzle. Piezoelectric inkjet printing requires high ink viscosity. Conductive inks with high viscosity formulated with metallic silver are preferably used at step 102, with compatible inks being selected so as not to affect the critical current of the superconducting segment (e.g., REBCO tape) and allow adequate adhesion on ceramic surfaces.

[0068] In one embodiment, an inkjet printer is used at step 102. The inkjet printer characteristics, namely the spacing (D) between the drops and the firing voltage which controls the resolution of the printed stabilizer patterns, are selected to obtain uniform silver lines at step 102. The thickness of the silver pattern(s) deposited at step 102 may further depend on the spreading properties of the ink on the substrate and on the droplet size. As understood by those skilled in the art, the firing voltage is the voltage amplitude applied to the piezoelectric part in the printhead of the inkjet printer to generate the required pressure for ejecting ink droplets to the substrate. The firing voltage thus controls the size and velocity of the ink droplets. Uniform continuous silver patterns may be created using an appropriate spacing between drops and an appropriate firing voltage. In one embodiment, the spacing between drops is 15 pm and the firing voltage is 16 V. Other embodiments may apply, depending on the application.

[0069] Although reference is made herein to inkjet printing being used at step 102 to deposit one or more stabilizer patterns on the outer surface of the superconducting layer, it should be understood that other techniques including, but not limited to, evaporation, magnetron sputtering, molecular beam epitaxy, electrodeposition may apply.

[0070] At step 104, the superconducting segment (e.g., REBCO tape) is annealed in the oxygen atmosphere for a predetermined time period, a step referred to as oxygenation. Step 104 allows the superconductor to attain the required stoichiometry to ensure that the desired superconducting properties are obtained. The step 104 of annealing is performed for a superconducting segment that is partially covered with a stabilizer (i.e., with the one or more stabilizer patterns deposited on the outer surface as per step 102). It may bedesirable for the superconducting segment to be annealed at a temperature between 300 °C and 600 °C. In this manner, the contact resistance between the stabilizer pattern(s) (e.g., silver line) created at step 102 and the superconducting (e.g., REBCO) layer is decreased.

[0071] In one embodiment, the parameters of the technique (e.g., inkjet printing) used to deposit the pattern(s) at step 102 and the oxygen annealing temperature used at step 104 may be optimized prior to proceeding with the method 100 in order to obtain highly conductive stabilizer patterns. It is desirable for the conductivity of the stabilizer patterns to be in the same order of magnitude as that of the stabilizer layer (described further below), even if the stabilizer pattern(s) and the stabilizer layer were to be made of different materials. In addition, it is desirable for the conductivity of the stabilizer patterns or stabilizer layer to be higher than the conductivity of the superconducting layer when the superconducting segment is in the normal state.

[0072] At step 106, a stabilizer layer is deposited to cover at least the outer surface of the superconducting layer having the stabilizer pattern(s) deposited thereon, with the stabilizer layer, when so deposited, being electrically connected to the stabilizer pattern(s) deposited at step 102 and covering all sides of the superconducting segment. In particular, the stabilizer pattern(s) connect electrically to the stabilizer layer through stabilizer material (e.g., silver) deposition. The stabilizer pattern(s) or the stabilizer layer connect electrically to the superconducting layer th rough annealing (step 102). In one embodiment, the same stabilizer material (e.g., silver) is used to deposit the pattern(s) (as per step 102) and the layer (as per step 106). In another embodiment, a stabilizer material (e.g. silver) is used to deposit the pattern(s) (as per step 102) and another stabilizer material (e.g. gold) is used to deposit the layer (as per step 106), provided the stabilizer materials have a conductivity which is higher than the normal state conductivity of the superconducting segment. In one embodiment, step 106 implies depositing the stabilizer layer so as to cover the outer surface of the superconducting layer with the stabilizer pattern(s) deposited thereon, as well as the remainder of the superconducting segment (i.e. the bottom surface and the side surfaces of the superconducting segment). The stabilizer layer may have any suitable thickness, which may be adjusted based on the intended application and required thickness of the superconducting segment. In some embodiments, the stabilizer layer may have the same thickness as that of the stabilizer pattern(s) deposited at step 102. Any suitable technique may be used to deposit thestabilizer layer. In one embodiment, the stabilizer layer is deposited by sputtering (e.g., magnetron sputtering). Other embodiments may apply.

[0073] Figs. 2A, 2B, and 2C illustrate one example of the application of the steps of the method 100 of Fig. 1 to a superconducting segment (also referred to herein as a sample) 200, and the resulting CFD superconducting segment. Any suitable superconducting segment 200 may be used. In the embodiment of Figs. 2A, 2B, and 2C, the superconducting segment 200 is a REBCO tape comprising a Hastelloy™ (C276™) substrate 202, a buffer layer 204, a REBCO (Zr-doped GdBaCuO) superconducting layer 206, and a silver stabilizer layer 208. In the illustrated embodiment, the buffer layer 204 is laid over the Hastelloy™ substrate 202, and the REBCO layer 206 is laid over the buffer layer 204, with the silver layer 208 surrounding the layered structure formed by the substrate 202, buffer layer 204, and REBCO layer 206, except for an upper (or outer) surface 210 of the REBCO layer 206. It should however be understood that, in other embodiments (such as the one illustrated in Figs. 2D, 2E, and 2F), the layered structure may be free of the surrounding silver layer 208. In one embodiment, the superconducting segment 200 is a commercial REBCO tape that is 4 mm wide with a critical current at 77 K and in self-field of about 100 to 110 A, and having a 50 pm thick Hastelloy™ substrate 202, a 0.58-0.78 pm thick buffer layer 204, a 0.8 pm thick REBCO layer 206, and a 2 pm thick silver layer 208.

[0074] Fig. 2A illustrates the step 102 of Fig. 1 of depositing a silver line 212 on the exposed REBCO surface 210. In the illustrated embodiment of Fig. 2A, the silver line 212 is deposited using inkjet printing. For example, an inkjet printer having a nozzle 214 configured to create silver drops 216 may be used. The silver line 212 may have any suitable dimensions. For example, a 3 pm thick and 0.5 mm wide silver line 212 may be deposited on the REBCO surface 210, with a coverage ratio (i.e. the ratio between the width of the silver line 212 and the total width of the superconducting segment 200) of 0.875. In the illustrated embodiment, the silver line 212 is deposited along the central axis A of the superconducting segment 200. It should however be understood that the silver line 212 may be deposited along a lateral edge 213a or 213b of the surface 210. In yet other embodiments (described further below), two substantially parallel silver lines may be deposited on the surface 210, with the first silver line being deposited along the first lateral edge 213a of the surface 210 and the second silver line being deposited along the second lateral edge 213b of the surface 210, which is opposite the first edge 213a. Thestabilizer pattern(s) may also be deposited at step 102 to form a geometrical pattern. For example, the silver lines may be deposited in a geometrical pattern (e.g., a zigzag pattern, a rectangular pattern, etc.) rather than straight line(s) as in 212. It should however be understood that, should such a geometrical pattern of stabilizer pattern(s) be deposited at step 102, it may be desirable for the geometrical pattern to have a linear symmetry along the length of the superconducting (e.g., REBCO) layer 206 (i.e. along the central axis A of the superconducting segment).

[0075] Fig. 2B illustrates the step 104 of Fig. 1 of oxygen annealing, whereby a zone (not shown) of low interfacial resistance is created below the silver line 212. As can be seen from Fig. 2B and as described herein above with reference to Fig. 1 , oxygen annealing is performed with the superconducting segment 200 being partially covered with stabilizer, i.e. with the superconducting segment 200 having part of the REBCO surface 210 having the silver line 212 deposited thereon and the remainder of the REBCO surface 210 having no stabilizer.

[0076] Fig. 2C illustrates the step 106 of Fig. 1 of depositing a silver layer 220 on the overall width (w) of the superconducting layer 206, to cover the REBCO surface 210.

[0077] Figs. 2D, 2E, and 2F illustrate another example of the application of the steps of the method 100 of Fig. 1 to a superconducting segment 200’ having no surrounding stabilizer (i.e. no silver stabilizer layer 208 surrounding the layered structure formed by the substrate 202, buffer layer 204, and REBCO layer 206), and the resulting CFD superconducting segment. The steps illustrated in Figs. 2D, 2E, and 2F are similarto those illustrated in Figs. 2A, 2B, and 2C, except that the step 106 of Fig. 1 illustrated in Fig. 2F involves depositing the silver layer 220 on all surfaces of the superconducting segment 200’ (rather than only on the REBCO surface 210, as illustrated in Fig. 2C).

[0078] Figs. 2G-2K illustrate another example of the application of the steps of the method 100 of Fig. 1 to the superconducting segment 200, and the resulting CFD superconducting segment. The embodiment of Figs. 2G-2K may be applicable when techniques (e.g., evaporation, magnetron sputtering, molecular beam epitaxy, or electrodeposition) other than maskless patterning techniques (such as inkjet printing, screen printing, or flexography) are used to deposit the stabilizer pattern(s) on the outer surface of the superconducting layer at step 102 of Fig. 1. In this embodiment, the step102 of Fig. 1 comprises a number of sub-steps illustrated in Fig. 2G, Fig. 2H, and Fig. 2I. As illustrated in Fig. 2G, a shadow mask 250 is first positioned on the outer surface of the superconducting segment 200, i.e. on the REBCO surface 210. The mask 250 is positioned so as to partially cover the REBCO surface 210, thereby creating at least one masked region and at least one unmasked region (not shown) of the REBCO surface 210. The mask 250 is designed (e.g., shaped) to allow for either a single stabilizer pattern or multiple stabilizer patterns to be deposited on the REBCO surface 210. For this purpose, the mask 250 has formed therein aperture(s) that define the unmasked region(s) of the REBCO surface 210 (when the mask 250 is positioned on the REBCO surface 210) and through which the stabilizer material is deposited on the REBCO surface 210. The size and shape of the mask 250 matches the desired size and shape of the stabilizer pattern(s), which are exposed when the mask 250 is removed after the stabilizer material has been deposited. The mask 250 may be made of any suitable material that is resistant to the deposition environment, mechanically stable, and capable of maintaining the features of the stabilizer pattern(s) without reacting with the superconducting layer. The mask 250 can include, but is not limited to, a metallic mask (such as stainless steel mask), a polymer mask (such as Kapton film), a glass mask, or a silicon mask.

[0079] In the illustrated embodiment, the mask 250 has a shape (e.g., a rectangular shape) and size (e.g., dimensions) that may substantially match those of the REBCO surface 210. It should however be understood that the dimensions of the mask 250 need not match those of the REBCO surface 210 in all embodiments. An elongated slot 252 is formed in the mask 250, running from one short edge 254a of the mask 250 to the opposite short edge 254b. The slot 252 is parallel to the long (or lateral) edges 256a, 256b of the mask 250 and is centered relative to the long edges 256a, 256b so as to be aligned with and extend along the central axis A when the mask 250 is positioned on the REBCO surface 210). The slot 252 shown in Fig. 2G allows for a single stabilizer pattern to be formed on the REBCO surface 210. It should however be understood that this is for illustrative purposes only and that more than one slot as in 252 may be formed in the mask 250 in order to allow for multiple stabilizer patterns to be deposited on the REBCO surface 210. For example, two parallel slots as in 252 may be formed along the long edges 256a, 256b. In addition, the slot(s) as in 252 may have any suitable shape, size, and / or position relative to the mask 250 in order to allow for stabilizer pattern(s) of any suitable dimension and / position to be deposited on the REBCO surface 210. For example, the apertureformed in the mask 250 may form a geometrical (e.g., zig-zag) pattern. Fig. 2L illustrates example embodiments of different shadow mask configurations that may be applied on the REBCO surface 210. In particular, Fig. 2L illustrates a first shadow mask 250i having a central slot 252i extending along the central axis A, a second shadow mask 2502 having a central slot 2522 forming a zigzag pattern, a third shadow mask 250s having a central slot 252s forming a rectangular pattern, and a fourth shadow mask 2504 comprising two slots 252 disposed adjacent the opposite edges 256a, 256b of the mask 250. The shadow masks 250i, 2502 , 250s, and 2504 of Fig. 2L may be used to respectively deposit the stabilizer patterns 212, 212’, 212”, and 212a, 212b illustrated in Figs. 8A, 8B, 8C, and 8D described further below. It should be understood that other embodiments may apply.

[0080] As illustrated in Fig. 2H, the stabilizer material (e.g., silver) is then deposited (e.g., by sputtering, as illustrated, or any other suitable technique such as evaporation, molecular beam epitaxy, or electrodeposition) onto both the masked and unmasked regions of the outer surface of the superconducting segment 200 (i.e. of the REBCO surface 210). As illustrated in Fig. 2I, prior to silver deposition (step 106), the mask 250 (having silver deposited thereon) is removed, leaving the deposited silver pattern (i.e. silver line 212) exclusively on the outer surface of the superconducting segment 200.

[0081] Fig. 2J illustrates the subsequent step 104 of Fig. 1 of oxygen annealing (similar to Fig. 2B described herein above) and Fig. 2K illustrates the step 106 of Fig. 1 of depositing the silver layer 220 on the overall width (w) of the superconducting layer 206 (similar to Fig. 2C described herein above) to cover the REBCO surface 210 and thus cover all sides of the superconducting segment 200.

[0082] Figs. 3A to 7E illustrate in further detail the application of the method 100 of Fig. 1 on a superconducting segment (or sample), according to different embodiments.

[0083] In the embodiment shown in Figs. 3A, 3B, 3C, 3D, and 3E, the method 100 is used to deposit a single silver pattern on a superconducting segment 200 having no upper (or top) stabilizer (e.g., silver) layer (reference 208 in Fig. 2A). As can be seen from Fig. 3A, the superconducting segment 200 comprises a substrate 202 on which a buffer layer 204 is disposed. A superconductor (e.g., REBCO) layer 206 is disposed on the buffer layer 204, with the superconductor’s top surface 210 being exposed. Opposite side stabilizer layers 208a, 208b and a bottom stabilizer layer 208c are however provided to cover thebottom and sides of the layered structure formed by the substrate 202, the buffer layer 204, and the superconductor layer 206.

[0084] A first high interfacial resistive layer 224a is created over (i.e. on top of) the surface 210, and a second high interfacial resistive layer 224b is created between an inner surface (not shown) of each side stabilizer layer 208a, 208b and each respective side surface 222a, 222b of the superconductor layer 206. The first high interfacial resistive layer 224a therefore fully covers the superconducting layer 206 (i.e. the top surface 210 thereof) and the second high interfacial resistive layer 224b fully covers the side surfaces 222a, 222b. The term “high”, when used herein with reference to an interfacial resistive layer, implies that the electrical resistance of the resistive layer is in a range between about I O8ohm.m2and about 1 ohm.m2. In contrast, the term “low”, when used herein with reference to an interfacial resistive layer, implies that the electrical resistance of the resistive layer is in a range between about 1012ohm.m2and about 108ohm.m2. As such, the electrical resistance of a low interfacial resistive layer is lower than the electrical resistance of a high interfacial resistive layer.

[0085] Fig. 3B illustrates the superconductor material’s layout after a stabilizer pattern (i.e. a single silver line 212) has been deposited on the superconductor’s top surface 210 (step 102 of Fig. 1). As in the embodiment illustrated in Fig. 2A, the silver line 212 is deposited along the central axis (reference A in Fig. 2A) of the superconducting segment 200. It should however be understood that the silver line 212 may be deposited at any suitable location on the surface 210 other than along the central axis A.

[0086] Fig. 3C illustrates the superconductor material’s layout during oxygenation (step 104 of Fig. 1). The superconducting segment 200 is placed in a furnace 226 configured to apply oxygen annealing to the superconductor material. After annealing, a first low interfacial resistive layer 228a is obtained between the superconductor’s top surface 210 and the silver line 212 (i.e. provided below the silver line 212), at the center of the superconducting material. The first high interfacial resistive layer 224a is thus separated into two portions (not shown) adjacent the silver line 212, with a first portion being provided on one side of the silver line 212 (and accordingly on one side of the low interfacial resistive layer 228a) and the second portion being provided on the other side of the silver line 212 (and accordingly on the other side of the low interfacial resistive layer 228a). In the example of Fig. 3C, the first portion of the first high interfacial resistive layer 224a isprovided on the left side of the silver line 212 (and of the low interfacial resistive layer 228a), and the second portion of the first high interfacial resistive layer 224a is provided on the right side of the silver line 212 (and of the low interfacial resistive layer 228a). As such, after annealing, each of the first high interfacial resistive layer 224a and the first low interfacial resistive layer 228a partially covers the top surface 210 of the superconducting layer 206. Furthermore, after annealing, the second high interfacial resistive layer 224b is replaced (as a result of the annealing process) by a second low interfacial resistive layer 228b created between the inner surface of each side stabilizer layer 208a, 208b and each respective side surface 222a, 222b of the superconductor layer 206. The second low interfacial resistive layer 228b thus fully covers the side surfaces 222a, 222b.

[0087] Fig. 3D illustrates the superconductor material’s layout following the deposition of the top stabilizer (i.e. silver) layer 220 on the overall width of the superconducting layer 206 (step 106 of Fig. 1). As can be seen from Fig. 3D, the first high interfacial resistive layer 224a remains on both (e.g., left and right) sides of the silver line 212, between the superconductor’s top surface 210 and the silver layer 220. As illustrated in Fig. 3E, the first high interfacial resistive layer 224a embodies the CFD which covers the left and right sides of the surface 210. The flow of current from the superconductor layer 206 to the stabilizer layer 220 is illustrated by arrows B1 , B2, B3, B4, and B5. As can be seen from Fig. 3E, the current is directed into the silver line 212 and towards the stabilizer layer 220. Five (5) current paths are created. The first current path (illustrated by arrow B1) passes current through the silver line 212 (along a direction normal to a plane of the surface 210) and directs the current towards the top (i.e. the outer surface) of the stabilizer layer 220. The second current path (illustrated by arrow B2) directs current through the stabilizer layer 220 (along the plane of the surface 210), above the first (or left in Fig. 3E) portion of the first high interfacial resistive layer 224a, and towards the side surface 222a. The third current path (illustrated by arrow B3) directs current through the stabilizer layer 220, above the second (or right) portion of the first high interfacial resistive layer 224a, and towards the opposite side surfaces 222b. The fourth current path (illustrated by arrow B4) directs the current through the superconducting layer 206 towards the side surface 222a, and through the side stabilizer layer 208a. The fifth current path (illustrated by arrow B5) directs the current through the superconducting layer 206 towards the opposite side surface 222b, and through the opposite side stabilizer layer 208b.

[0088] As previously noted with reference to Fig. 1 , although Figs. 2A, 2B, 2C and Figs. 3A, 3B, 3C, 3D, 3E illustrate a single stabilizer pattern (i.e. silver line 212) being deposited on the superconductor’s top surface 210, it should be understood that multiple stabilizer patterns (i.e. silver lines as in 212) may be deposited on the superconducting segment surface 210. An embodiment in which two (2) silver lines are deposited on the superconducting segment surface 210 will now be described with reference to Figs. 4A, 4B, 4C, and 4D.

[0089] Fig. 4A illustrates the superconductor material’s layout after two stabilizer patterns (i.e. left and right silver lines 212a and 212b) have been deposited on the superconducting segment’s top surface 210. The first silver line 212a is deposited along a first edge (not shown) of the surface 210, adjacent the first side surface 222a, and the second silver line 212b is deposited along the second edge (not shown) opposite the first edge, adjacent the second side surface 222b. It should however be understood that more than two silver lines as in 212a, 212b may be deposited on the surface 210 and that the silver lines may be deposited at any suitable location on the surface 210 other than along the edges of the surface 210. As can be seen on Fig. 4A, the first high interfacial resistive layer 224a is provided on top of (i.e. fully covers) the surface 210 and the second high interfacial resistive layer 224b is provided at (i.e. fully covers) the side surfaces 222a, 222b.

[0090] Fig. 4B illustrates the superconductor material’s layout during oxygenation using the furnace 226. After annealing, a first low interfacial resistive layer 230a is obtained between the superconductor’s top surface 210 and each silver line 212a, 212b, adjacent the edges (not shown) of the superconducting layer’s surface 210. The first low interfacial resistive layer 230a thus comprises two portions (not shown), with a first portion being provided adjacent one edge of the surface 210 (i.e. below the left silver line 212a) and the second portion being provided adjacent the opposite edge of the surface 210 (i.e. below the right silver line 212b). After annealing, the first high interfacial resistive layer 224a remains in the middle of the superconductor material, i.e. between the silver lines 212a, 212b (and accordingly between the first portion and the second portion of the first low interfacial resistive layer 230a). As such, after annealing, each of the first high interfacial resistive layer 224a and the first low interfacial resistive layer 230a partially covers the top surface 210 of the superconducting layer 206. Furthermore, after annealing, the second high interfacial resistive layer 224b is replaced (as a result of the annealing process) by asecond low interfacial resistive layer 230b created between each side stabilizer layer 208a, 208b and each respective side surface 222a, 222b of the superconductor layer 206. The second low interfacial resistive layer 230b thus fully covers the side surfaces 222a, 222b.

[0091] Fig. 4C illustrates the superconductor material’s layout following the deposition of the top stabilizer layer 220 on the superconducting layer 206. As can be seen from Fig. 4C, the first high resistive interfacial layer 224a remains between the superconductor’s top surface 210 and the silver layer 220, in the middle of the superconductor material. As illustrated in Fig. 4D, the CFD formed by the first high interfacial layer 224a is centered and covers a portion (e.g., between about 70% and about 99%) of the width of the superconductor layer 206. The flow of current from the superconductor layer 206 to the top stabilizer layer 220 and the side stabilizer layers 208a, 208b is illustrated by arrows C1 , C2, C3, and C4. As can be seen from Fig. 4D, four (4) current paths are created. The first current path (illustrated by arrow C1) passes current through the superconducting layer 206 and directs the current through the first silver line 212a and towards the top of the stabilizer layer 220. The second current path (illustrated by arrow C2) passes current through the superconducting layer 206 and directs the current through the second silver line 212b and towards the top of the stabilizer layer 220. The third current path (illustrated by arrow C3) directs the current through the superconducting layer 206 towards the side surface 222a, and through the side stabilizer layer 208a. The fourth current path (illustrated by arrow C4) directs the current through the superconducting layer 206 towards the opposite side surface 222b, and through the opposite side stabilizer layer 208b.

[0092] It should be understood that the method described herein may also be used on a superconductor material having no surrounding stabilizer. This is illustrated in Figs. 5A, 5B, 5C, 5D, 5E and in Figs. 6A, 6B, 6C, and 6D.

[0093] As can be seen from Fig. 5A, the superconducting segment 200’ without stabilizer comprises the layered structure formed by the substrate 202, the buffer layer 204, and the superconductor layer 206 having the exposed top surface 210 and sides surfaces 222a, 222b. Unlike the superconducting segment 200 described herein above, the superconducting segment 200’ comprises no opposite side stabilizer layers 208a, 208b and no bottom stabilizer layer 208c. The first high interfacial resistance 224a isprovided on top of (i.e. fully covers) the surface 210 and the second high interfacial resistive layer 224b is provided at (i.e. fully covers) each side surface 222a, 222b.

[0094] Fig. 5B illustrates the superconductor material’s layout after a single stabilizer pattern (i.e. silver line 212) has been deposited on the surface 210, along the central axis A. Fig. 5C illustrates the superconductor material’s layout during oxygenation using furnace 226. After annealing, a low interfacial resistive layer 232 is created between the superconductor’s top surface 210 and the silver line 212, at the center of the superconducting layer 206. The first high interfacial resistive layer 224a is thus separated into two portions (not shown), with a first portion being provided on one side (e.g., left side) of the silver line 212 (and accordingly on one side of the low interfacial resistive layer 232) and the second portion being provided on the other side (e.g., right side) of the silver line 212 (and accordingly on the other side of the low interfacial resistive layer 232). As such, after annealing, each of the first high interfacial resistive layer 224a and the low interfacial resistive layer 232 partially covers the top surface 210 of the superconducting layer 206. Furthermore, after annealing, the second high interfacial resistive layer 224b remains at (and therefore fully covers) the side surfaces 222a, 222b.

[0095] Fig. 5D illustrates the superconductor material’s layout following the deposition of a bottom stabilizer (i.e. silver) layer 220a, a top stabilizer layer 220b, and side stabilizer layers 220c, 220d surrounding the overall layout of the superconductor material. As can be seen from Fig. 5D, the first high resistive interfacial layer 224a remains between the superconductor’s top surface 210 and the top stabilizer layer 220b, and the second resistive interfacial layer 224b remains, between each side surface 222a, 222b and each respective side stabilizer layer 220c, 220d. As illustrated in Fig. 5E, the CFD formed by the high resistive interfacial layers 224a, 224b covers the left and right sides of the surface 210, as well as the side surfaces 222a, 222b. The flow of current from the superconductor layer 206 to the top stabilizer layer 220b and side stabilizer layers 220c, 220d is illustrated by arrows D1 , D2, and D3. As can be seen from Fig. 5E, three (3) current paths are created. The first current path (illustrated by arrow D1) passes current through the silver line 212 and directs the current towards the top stabilizer layer 220b. The second current path (illustrated by arrow D2) directs current through the top stabilizer layer 220b, above the first portion of the first high interfacial resistive layer 224a, and towards the first side surface 222a, through the first side stabilizer layer 220c. The third current path (illustrated by arrow D3) directs current through the top stabilizer layer 220b, above the secondportion of the first high interfacial resistive layer 224a, and towards the second side surface 222b, through the second side stabilizer layer 220d.

[0096] Fig. 6A illustrates a plot 600 of normal zone propagation velocity (NZPV) results obtained following the CFD fabrication sequence illustrated and described herein with reference to Figs. 5A to 5E. In particular, the plot 600 shows the measured NZPV values versus the applied current for a CFD tape (illustrated by triangles 602) and for a regular (or classical) tape (illustrated by circles 604). From the plot 600, it can be seen that the NZPV of the CFD tape is increased by a factor of about 6 to 7 with respect to the regular tape. The increase in NZPV in turn renders the quench uniform and facilitate the detection of the quench.

[0097] Fig. 6B illustrates a plot 610 of NZPV results following the CFD fabrication sequence illustrated and described herein with reference to Figs. 2G-2K In particular, the plot 610 shows the measured NZPV values versus the applied currents for a CFD tape fabricated with the method described herein with reference to Figs. 2G-2K (illustrated by squares 612), for a CFD tape fabricated with the known method described in US Patent No. 9,029,296 (illustrated by triangles 614), and for a regular tape (illustrated by circles 616). It can be seen that the NZPV of the CFD tape fabricated using the method proposed herein is identical to that of the CFD tape fabricated using the known method, with both showing an increase by a factor of 9 to 10 compared to the regular tape. This demonstrates that the method proposed herein is a valid approach for producing CFD tapes with the same efficiency as the known method.

[0098] Continuing with the embodiment in which the method described herein may also be used on a superconductor material having no surrounding stabilizer, Fig. 7A illustrates the superconductor material’s layout after two silver lines 212a and 212b are deposited along respective edges (not shown) of the superconductor’s top surface 210 and adjacent respective ones of the first and second side surfaces 222a, 222b. The first high interfacial resistive layer 224a is provided on top of (i.e. fully covers) the surface 210 and the second high interfacial resistive layer 224b is provided at (i.e. fully covers) the side surfaces 222a, 222b.

[0099] Fig. 7B illustrates the superconductor material’s layout during oxygenation using the furnace 226 where, after annealing, a low interfacial resistive layer 234 is obtainedbetween the superconductor’s top surface 210 and each silver line 212a, 212b, at the edges (not shown) of the superconducting material. The low interfacial resistive layer 234 thus comprises two portions (not shown), with a first portion being provided adjacent one edge of the surface 210 and the second portion being provided adjacent the opposite edge of the surface 210. After annealing, the first high interfacial resistive layer 224a remains in the middle of the superconductor material, i.e. between the silver lines 212a, 212b (and accordingly between the first portion and the second portion of the low interfacial resistive layer 234). As such, after annealing, each of the first high interfacial resistive layer 224a and the low interfacial resistive layer 234 partially covers the top surface 210 of the superconducting layer 206. Furthermore, after annealing, the second high interfacial resistive layer 224b remains at (and fully covers) each side surface 222a, 222b.

[0100] Fig. 7C illustrates the superconductor material’s layout following the deposition of a bottom stabilizer (i.e. silver) layer 220a, a top stabilizer layer 220b, and side stabilizer layers 220c, 220d surrounding the overall layout of the superconducting segment. As can be seen from Fig. 7C, the first high resistive interfacial layer 224a remains between the superconductor’s top surface 210 and the top stabilizer layer 220b, and the second high resistive interfacial layer 224b remains, between each side surface 222a, 222b and each respective side stabilizer layer 220c, 220d. As illustrated in Fig. 7D, the CFD formed by the resistive interfacial layers 224a, 224b covers the left and right edges of the surface 210 and the side surfaces 222a, 222b. The flow of current from the superconductor layer 206 to the top stabilizer layer 220b is illustrated by arrows E1 and E2. As can be seen from Fig. 7D, two (2) current paths are created. The first current path (illustrated by arrow E1) passes current through the superconducting layer 206 and directs the current through the first silver line 212a and towards the top stabilizer layer 220b. The second current path (illustrated by arrow E2) passes current through the superconducting layer 206 and directs the current through the second silver line 212b and towards the top stabilizer layer 220b.

[0101] Referring now to Figs. 8A, 8B, 8C, and 8D, as previously noted with reference to Fig. 1 , step 102 may comprise depositing a single silver line or multiple silver lines at any suitable position on the superconducting segment’s surface 210, and / or depositing a pattern of silver lines. Fig. 8A is a top view illustrating the embodiment described above with reference to Figs. 2A to 2C, Figs. 3A to 3E, and Figs. 5A to 5E, where a single silver line 212 is deposited on the surface 210, along the central axis A. In other embodiments, the silver line 212 may be deposited at other locations on the surface 210, including, butnot limited to, along either of the opposed longitudinal lateral edges 802a, 802b of the surface 210. Fig. 8B is a top view illustrating an embodiment in which a silver line 212’ is deposited on the surface 210 in a zigzag pattern that extends along and is symmetrical about the central axis A. Fig. 8C is a top view illustrating an embodiment in which a silver line 212” is deposited on the surface 210 in a rectangular pattern that extends along and is symmetrical about the central axis A. Patterns other than zigzag and rectangular may also apply. Fig. 8D is a top view illustrating the embodiment described above with reference to Figs. 4A to 4D and Figs. 7 A to 7D, in which two silver lines 212a, 212b are deposited on the surface 210, with the first silver line 212a being deposited along the first edge (reference 802a in Fig. 8A) of the surface 210 and the second silver line 212b being deposited along the second edge (reference 802b in Fig. 8A). It should however be understood that, when two silver lines as in 212a, 212b, are deposited on the surface 210, these silver lines may be deposited at any suitable location other than along the edges 802a, 802b. Other embodiments may apply.

[0102] In one embodiment, the method described herein may allow to reduce costs compared to existing techniques. Using the method described herein may allow to create stabilizer (e.g., silver) patterns on the surface of the superconducting (e.g., REBCO) layer without the need to use a shadow mask when inkjet printing is used. Furthermore, using the method described herein may alleviate the need to etch the stabilizer to create the CFD layer. In addition, the method described herein may be readily integrated into the fabrication process of commercial superconducting segments, between superconducting layer deposition and oxygenation. In particular, only one step may need to be added to the superconducting segment fabrication process. Furthermore, the need for using chemicals may be alleviated. The method described herein may therefore provide added flexibility since it may enable compatibility with various fabrication processes of superconducting segments for mass production. The method described herein may also reduce the production cost of CFD superconducting segments while enabling the fabrication of stabilizer patterns with high resolution and repeatability.

[0103] The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure.

[0104] Various aspects of the systems and methods described herein may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Although particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects. The scope of the following claims should not be limited by the embodiments set forth in the examples, but should be given the broadest reasonable interpretation consistent with the description as a whole.

Claims

WHAT IS CLAIMED IS:

1. A method for manufacturing a current flow diverter (CFD) for a superconducting segment, the method comprising: depositing at least one pattern of a stabilizer material on a portion of an outer surface of a superconducting layer of the superconducting segment and creating a first interfacial resistive layer on the outer surface of the superconducting layer, adjacent the at least one pattern of the stabilizer material; annealing, subsequent to depositing the at least one pattern of the stabilizer material, the superconducting segment in an oxygen atmosphere and creating a second interfacial resistive layer between the at least one pattern of the stabilizer material and the outer surface of the superconducting layer, the second interfacial resistive layer having an electrical resistance lower than that of the first interfacial resistive layer; and depositing, subsequent to annealing the superconducting segment, a layer of the stabilizer material over at least the outer surface of the superconducting layer having the at least one pattern of the stabilizer material deposited thereon and creating at least one path for diverting, via the first and second interfacial resistive layers, a flow of electrical current from the superconducting layer to the layer of the stabilizer material.

2. The method of claim 1 , wherein the superconducting segment is a layered structure having a top surface formed by the outer surface of the superconducting layer, a bottom surface, and opposite side surfaces, and further wherein, prior to the depositing the at least one pattern of the stabilizer material, the outer surface of the superconducting layer is free of the stabilizer material while the bottom and side surfaces of the superconducting segment have the stabilizer material deposited thereon.

3. The method of claim 2, wherein depositing the layer of the stabilizer material comprises depositing the layer of the stabilizer material only on the outer surface of the superconducting layer.

4. The method of claim 1 , wherein the superconducting segment is a layered structure having a top surface formed by the outer surface of the superconducting layer, a bottom surface, and opposite side surfaces, and further wherein, prior to the depositing the at least one pattern of the stabilizer material, the outer surface of the superconducting layer and the bottom and side surfaces of the superconducting segment are free of the stabilizer material.

5. The method of claim 4, wherein depositing the layer of the stabilizer material comprises depositing the layer of the stabilizer material on the bottom and side surfaces of the superconducting segment in addition to the outer surface of the superconducting layer.

6. The method of any one of claims 1 to 5, wherein the layer of the stabilizer material is deposited on the outer surface ofthe superconducting layer overthe at least one pattern of the stabilizer material.

7. The method of any one of claims 1 to 6, wherein depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along one or more lines.

8. The method of any one of claims 1 to 7, wherein depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along a central axis of the superconducting segment.

9. The method of any one of claims 1 to 7, wherein depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material along a first straight line and a second straight line parallel to the first line, the first line deposited along a first lateral edge of the superconducting layer and the second line is deposited along a second lateral edge of the superconducting layer opposite to the first edge.

10. The method of any one of claims 1 to 8, wherein depositing the at least one pattern of the stabilizer material on the outer surface of the superconducting layer comprises depositing the stabilizer material in a geometrical pattern.

11. The method of claim 10, wherein the geometrical pattern is symmetrical about a central axis of the superconducting segment.

12. The method of any one of claims 1 to 11 , wherein the at least one pattern of the stabilizer material is deposited using one of inkjet printing, screen printing, and flexography.

13. The method of any one of claims 1 to 11 , wherein the at least one pattern of the stabilizer material is deposited using one of evaporation, magnetron sputtering, molecular beam epitaxy, and electrodeposition.

14. The method of claim 13, wherein depositing the at least one pattern of the stabilizer material comprises: positioning a shadow mask on the outer surface of the superconducting layer, the shadow mask partially covering the outer surface to create at least one masked region and at least one unmasked region; depositing the stabilizer material on the at least one masked region and the at least one unmasked region of the outer surface of the superconducting layer; and removing the shadow mask to expose the at least one pattern of the stabilizer material formed on the outer surface of the superconducting layer.

15. The method of claim 14, wherein the shadow mask has formed therein at least one aperture defining the at least one unmasked region of the superconducting layer, the stabilizer material deposited on the outer surface of the superconducting layerthrough the at least one aperture.

16. The method of claim 15, wherein the at least one aperture is an elongated slot centered relative to lateral edges of the shadow mask, further wherein positioning the shadow mask on the outer surface of the superconducting layer comprises aligning the slot with a central axis of the superconducting segment for depositing the stabilizer material along the central axis.

17. The method of any one of claims 1 to 16, wherein the layer of the stabilizer material is deposited by sputtering.

18. The method of any one of claims 1 to 17, wherein the stabilizer material comprises silver.

19. The method of any one of claims 1 to 18, wherein the superconducting layer comprises Rare-earth barium copper oxide (REBCO).

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