CuC-based copper oxide high-temperature superconducting material and preparation method and application thereof

Abstract

The invention relates to the technical field of high-temperature superconducting materials, and discloses a CuC-based copper oxide high-temperature superconducting material and a preparation method and application thereof. The chemical formula of the CuC-based copper oxide is (Cux, MyC1-x-y) Ba2Ca3Cu4O11 + delta, M is selected from at least one of B, Al, Si, Ge, S, Se and Te, x is more than or equal to 0.1 and less than or equal to 0.9, and y is more than 0 and less than or equal to 1. The preparation method comprises the following steps: firstly, respectively synthesizing BaCuO2 and Ca2CuO3 precursor powder, then mixing the precursor powder with a compound containing an M element, and finally preparing the target material for coating through multiple times of ball milling and sintering. According to the method, an unstable gas carbon source in a traditional process is replaced by optimization of doping elements and introduction of a stable solid doping source, the superconducting target material with uniform components and high stability is successfully prepared, and a superconducting strip prepared from the CuC-based copper oxide target material is high in superconducting transition temperature and excellent in long-term stability. And the key problems of difficult component control and narrow process window in the preparation process of the (Cu, C) Ba2Ca3Cu4O11 + delta material are successfully solved.

Description

Technical Field

[0001] This invention relates to the field of high-temperature superconducting materials technology, and in particular to a novel CuC-based compound for coating high-temperature superconducting tapes and its preparation method. Background Technology

[0002] High-temperature superconducting materials exhibit zero resistance and perfect diamagnetism even at liquid nitrogen temperatures, making them promising candidates for both high-voltage (e.g., superconducting cables, magnets) and low-voltage (e.g., superconducting quantum interference devices) applications. Among numerous high-temperature superconducting materials, copper-based superconductors possess the highest superconducting transition temperature (Tc). (Cu,C)Ba₂Ca₃Cu₄O 11+δ CuC1234, abbreviated as CuC1234, is a copper oxide high-temperature superconductor. As a new generation of copper-based high-temperature superconductors, high-temperature superconducting thin films obtained by using CuC1234 as a target material exhibit excellent properties such as high irreversible field, low anisotropy and high critical current density (Jc), and are considered to be highly promising candidate materials for high-voltage applications.

[0003] However, the practical application of CuC-1234 faces significant challenges in its preparation. Obtaining high-quality single-crystal or polycrystalline samples of bulk CuC-1234 typically requires extreme conditions, such as ultra-high pressures of 3.5 to 6 GPa and high temperatures of 1000 to 1200 °C. These demanding synthesis conditions result in demanding equipment, complex processes, high costs, and difficulties in large-scale production, severely limiting the fundamental research and industrial development of this material. In actual preparation, the reproducibility of these conditions is poor.

[0004] Secondly, in the more practical fabrication of thin films and tapes, especially in physical vapor deposition techniques such as pulsed laser deposition, CuC-1234 also performs poorly. Specifically, the superconducting properties of the thin films are strongly dependent on the process parameters during deposition, such as the concentration of carbonate (CO3-). 2- Carbon dioxide (CO2) is often used as a dopant in CuC-1234 to stabilize the crystal structure, as disclosed in the prior art of patent application publication number CN118308692A. 2- The gas source used in this invention is CO2 gas for C doping during thin film deposition. However, during the experiment, the inventors discovered that even small fluctuations in gas flow rate directly lead to instability in the carbon and oxygen content of the film, resulting in significant deterioration of phase purity and superconducting properties, thus causing a low superconducting transition temperature. Therefore, using CO2 gas for C doping during thin film deposition has a narrow process window. Furthermore, weak grain boundary connectivity in the film causes the actual critical current density to be much lower than the theoretical value. Therefore, CuC-1234 materials prepared in the prior art often suffer from low superconducting transition temperature and low critical current density.

[0005] Therefore, there is an urgent need for a new design concept and preparation scheme for high-performance superconducting materials to broaden the process window and improve the stability and repeatability of the preparation process, so as to improve the superconducting transition temperature and stability of high-temperature superconducting materials. Summary of the Invention

[0006] To address the issues of low superconducting transition temperature and poor stability in the aforementioned high-temperature superconducting materials, this invention provides a CuC-based copper oxide high-temperature superconducting material, its preparation method, and its applications.

[0007] The specific technical solution of this invention is as follows:

[0008] On one hand, the present invention provides a CuC-based copper oxide high-temperature superconducting material, wherein the chemical formula of the CuC-based copper oxide is (Cu x M y C 1-x-y Ba2Ca3Cu4O 11+δ M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, and 0.1≤x≤0.9, 0<y≤1.

[0009] The inventors discovered in experiments that doping CuC-1234 material with element M results in a CuC-based copper oxide that stabilizes the structure of the CuC-based copper oxide and significantly stabilizes the process for preparing high-temperature superconducting tapes. Superconducting thin films prepared using this CuC-based copper oxide as a target material exhibit stable and relatively high superconducting transition temperatures. The chemical formula of the CuC-based copper oxide obtained after doping with element M is (Cu... x M y C 1-x-y Ba2Ca3Cu4O 11+δ M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, and 0.1 ≤ x ≤ 0.9, 0 < y ≤ 1.

[0010] It is understandable that in CuC-1234 material, δ represents the non-stoichiometric offset of oxygen content in the actual material, and typically, 0 < δ < 1.

[0011] The target material preparation of the CuC-based copper oxide high-temperature superconducting material can be carried out by any one of the following methods: solid-state sintering, sol-gel method, and precipitation method, including but not limited to these.

[0012] On the other hand, the present invention provides a method for preparing CuC-based copper oxide high-temperature superconducting materials, which includes the following steps:

[0013] Step S1: Synthesize pure-phase BaCuO2 precursor;

[0014] Step S2: Synthesize pure-phase Ca2CuO3 precursor;

[0015] Step S3: According to the molar ratio of M:Ba:Ca:Cu of y:2:3:4, the compound containing element M is mixed with BaCuO2 precursor, Ca2CuO3 precursor and CuO by ball milling, and then subjected to high temperature sintering and ball milling in sequence. The high temperature sintering and ball milling are repeated several times to obtain a CuC-based copper oxide high temperature superconducting material.

[0016] in:

[0017] The element M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, where 0 < y ≤ 1.

[0018] The preparation method of the CuC-based copper oxide of the present invention includes: firstly, synthesizing BaCuO2 and Ca2CuO3 precursor powders respectively; then mixing the precursor powders with a compound containing element M and CuO; and finally preparing a target material for coating by ball milling and sintering multiple times. This method, through optimization of doping elements and the introduction of a stable solid doping source to replace the unstable gaseous carbon source in traditional processes, successfully prepares a superconducting target material with uniform composition and high stability, and successfully solves the problem of (Cu,C)Ba2Ca3Cu4O 11+δ The key challenges in material preparation are difficulty in controlling composition and a narrow process window. The superconducting tape prepared from the CuC-based copper oxide target of this invention exhibits high stability in superconducting transition and excellent long-term stability, with no performance degradation after 6 months of storage.

[0019] This invention promotes the full reaction and phase stability of raw materials through active precursor induction. Specifically, in step S1, a BaCuO2 precursor is synthesized, and in step S2, a Ca2CuO3 precursor is synthesized. Based on BaCuO2 and Ca2CuO3 as active precursors, at least the following two effects are achieved:

[0020] On the one hand, the interdiffusion rates of barium oxide (barium carbonate raw material formed at high temperature) and copper oxide, and calcium oxide (calcium carbonate raw material formed at high temperature) and copper oxide are relatively fast, thus enabling the rapid formation of BaCuO2 precursor and Ca2CuO3 precursor. This ensures the full reaction of barium, copper, and calcium raw materials. On the other hand, the active precursors BaCuO2 and Ca2CuO3 can effectively promote the uniform doping of element M during the solid-state reaction to form CuC-based compounds.

[0021] As a preferred embodiment of the above preparation method, in step S3, at least one ball milling treatment is performed using wet ball milling. Wet ball milling effectively mixes the BaCuO2 precursor, Ca2CuO3 precursor, and the solid material of element M, thereby creating an optimal chemical reaction environment. This promotes the rapid diffusion of element M into the precursor pre-structure composed of BaO, CuO, and CaO layers via solid-phase ion reactions, ultimately achieving uniform doping of element M. The medium used in the wet ball milling is selected from one or more of methanol, ethanol, isopropanol, n-butanol, acetone, n-hexane, and cyclohexane.

[0022] As a preferred embodiment of the above preparation method, in step S3, the compound containing element M is selected from oxides of M, MO. 2- MO3 2- MO 3- MO4 2- or MO4 4- with Ba 2+ Ca 2+ At least one of the compounds that make up the composition.

[0023] As a preferred embodiment of the above preparation method, in step S3, M is selected from one or more of the following substances:

[0024] B2O3, Al2O3, SiO3, GeO3, SO3, SO3, SeO3, TeO2, TeO, Ca3(BO3)2, Ba3(BO3)2, CaB4O7·4H2O, BaB4O7, Ca( BO2)3, Ba(BO3)3, Ca[Al(OH)4]5, Ba[Al(OH)4]2, CaAl2O4, BaAl2O4, CaSiO3, BaSiO3, Ca2SiO4, Ba2SiO4 , Ca2Si2O5, Ba2Si2O5, CaGeO3, BaGeO3, CaSO4·2H2O, CaSO4·0.5H2O, BaSO4, CaSO3·0.5H2O, BaSO3, CaS 2O3, BaS2O3, CaS2O8, BaS2O8, CaSeO4·2H2O, BaSeO4, CaSeO3, BaSeO3, CaTeO4, BaTeO4, CaTeO3, BaTeO3.

[0025] As a preferred embodiment of the above preparation method, in step S3, the high-temperature sintering temperature is 850~950℃, the sintering time is 10~50 hours, and the ball milling time is 1~100 hours.

[0026] As a preferred embodiment of the above preparation method, in step S3, the high-temperature sintering and ball milling treatment are repeated 1 to 20 times.

[0027] As a preferred embodiment of the above preparation method, in step S1, the method for synthesizing the pure phase BaCuO2 precursor is as follows: barium carbonate powder and copper oxide powder are ball-milled at a molar ratio of 1:0.9~1, followed by high-temperature sintering and ball milling; the high-temperature sintering and ball milling are repeated several times to obtain the pure phase BaCuO2 precursor.

[0028] As a preferred embodiment of the above preparation method, in step S2, the method for synthesizing the pure phase Ca2CuO3 precursor is as follows: calcium carbonate powder and copper oxide powder are ball-milled at a molar ratio of 1:1 to 1.2, followed by high-temperature sintering and ball milling; the high-temperature sintering and ball milling are repeated several times to obtain the pure phase Ca2CuO3 precursor.

[0029] Using BaCuO2, formed by the solid-state reaction of barium carbonate powder and copper oxide powder at a molar ratio of 1:0.9~1, as a precursor, and Ca2CuO3, formed by the solid-state reaction of calcium carbonate powder and copper oxide powder at a molar ratio of 1:1~1.2, as a precursor, can effectively achieve full reaction of raw materials and uniform doping of element M.

[0030] Based on the above preparation method and the above CuC-based copper oxide, the present invention also provides an application of CuC-based copper oxide in the preparation of superconducting thin films.

[0031] Using the aforementioned CuC-based copper oxide as a target material, it can be applied to evaporation coating (including vapor deposition, laser deposition, etc.); sputtering coating (including magnetron sputtering, reactive sputtering, etc.); ion plating (including arc ion plating, ion beam assisted deposition, etc.); plasma-enhanced chemical vapor deposition (PECVD); metal-organic chemical vapor deposition (MOCVD); atomic layer deposition (ALD); metal-organic deposition (MOD) and other methods to deposit films, thereby obtaining superconducting thin films.

[0032] It is understandable that CuC-based copper oxides used for coating high-temperature superconducting tapes are usually doped with other compounds during tape preparation to improve pinning ability. The parent material is the aforementioned CuC-based copper oxide, and all of these are within the scope of protection of this invention.

[0033] Based on the above preparation method and the above CuC-based copper oxide, the present invention also provides a method for preparing a high-temperature superconducting tape, which includes the following steps: using the above CuC-based copper oxide as a target material, and depositing a superconducting thin film on the base tape using pulsed laser deposition technology.

[0034] Preferably, the process parameters for pulsed laser deposition include: oxygen pressure of 5~40 Pa, deposition temperature of 500℃~1000℃, and laser energy density of 0.5~5 mJ / cm³. 2 .

[0035] In addition, in conventional techniques, carbonate (CO3) 2- The superconducting material is used as a dopant in CuC-1234 to stabilize the crystal structure. Based on the above-mentioned technical points of this invention, this conventional technique can also be further employed to further improve the performance of the superconducting tape film. Optionally, CO2 is introduced during the film deposition process.

[0036] As a preferred method, continuous coating is performed using roll-to-roll equipment in the preparation of high-temperature superconducting tapes.

[0037] Compared with the prior art, the present invention has the following technical effects:

[0038] (1) This invention provides a CuC-based copper oxide with the chemical formula (Cu x M y C 1-x-y Ba2Ca3Cu4O 11+δ M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, where 0.1 ≤ x ≤ 0.9 and 0 < y ≤ 1. The CuC-based copper oxide obtained by doping CuC-1234 material with element M can greatly stabilize the process for preparing high-temperature superconducting tapes. The superconducting thin films prepared using the CuC-based copper oxide as a target material have stable and high superconducting transition temperatures.

[0039] (2) This invention provides a method for preparing the above-mentioned CuC-based copper oxide, comprising: firstly synthesizing BaCuO2 and Ca2CuO3 precursor powders respectively, then mixing the above-mentioned precursor powders with a compound containing element M and CuO, and finally preparing a target material for coating by ball milling and sintering multiple times. This method, by optimizing the doping elements and introducing a stable solid doping source to replace the unstable gaseous carbon source in the traditional process, successfully prepares a superconducting target material with uniform composition and high stability, and solves the problem of (Cu,C)Ba2Ca3Cu4O 11+δ The key challenges in material preparation are difficulty in controlling composition and a narrow process window. The superconducting tape prepared from the CuC-based copper oxide target of this invention exhibits high stability in superconducting transition and excellent long-term stability, with no performance degradation after 6 months of storage. Attached Figure Description

[0040] Figure 1 The images show the appearance of the CuC-based copper oxide prepared in Example 1, where (a) is the appearance of the CuC-based copper oxide powder and (b) is the appearance of the CuC-based copper oxide powder after being pressed and polished.

[0041] Figure 2 This is a SEM image of the CuC-based copper oxide powder prepared in Example 1.

[0042] Figure 3 The images show (a) XRD pattern and (b) surface morphology of the CuC-based copper oxide film prepared in Example 1.

[0043] Figure 4 The images show the appearance of the superconducting thin films prepared in Examples 1 and 4, where (a) is a sample coated on a single crystal substrate and (b) is a short sample of a high-temperature superconducting tape with a Hassell alloy substrate.

[0044] Figure 5 The graphs show the resistance-temperature variation of the superconducting thin films prepared in Examples 1 to 3.

[0045] Figure 6 The graphs show the resistance-temperature variation of the superconducting thin films prepared in Examples 4 and 5.

[0046] Figure 7 The graphs show the resistance-temperature variation of the superconducting thin films prepared in Examples 6, 7, and 8.

[0047] Figure 8 The graphs show the resistance-temperature variation of the superconducting thin films prepared in Examples 9-13.

[0048] Figure 9 The resistance-temperature curves are for the superconducting thin films prepared in Comparative Examples 1 to 4. Detailed Implementation

[0049] The present invention will be further described below with reference to embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0050] The substrate used for thin film deposition is a conventional substrate in the art, and the purpose is to study the effects of the target material and thin film deposition method of the present invention. A Hastelloy substrate is a flexible metal alloy strip, referring to a substrate on which a conventional transition layer is deposited, and the outermost layer is a CeO (cerium oxide) layer or an LMO layer. The thin film is deposited on the surface of the CeO or LMO layer (LaMnO3 layer). In the following embodiments, the effects of the target material and deposition method of the present invention are demonstrated by depositing a film on the surface of a soft substrate with an LMO layer or a CeO layer.

[0051] Example 1

[0052] A CuC-based copper oxide target and a high-temperature superconducting tape are provided, and the preparation steps are as follows:

[0053] (1) First, BaCO3 and CuO were weighed and mixed at a molar ratio of 1:1, and then dry-ball-milled for 4 hours. The mixture was then sintered at 850°C for a solid-state reaction for 20 hours. Subsequently, the sintered material was dry-ball-milled for 4 hours, sintered at 850°C for a solid-state reaction for 24 hours, and then dry-ball-milled again for 4 hours before sintering at 900°C for another 24 hours. After three sintering processes, pure-phase BaCuO2 powder was obtained.

[0054] (2) Next, CaCO3 and CuO were weighed and mixed at a molar ratio of 2:1, dry-milled for 4 hours, and then sintered at 880℃ for 20 hours for a solid-state reaction. The sintered material was then ball-milled again for 3 hours and sintered at 900℃ for 24 hours. The sintered material was then ball-milled for another 5 hours and sintered at 950℃ for 24 hours. After three sintering processes, pure phase Ca2CuO3 powder was obtained.

[0055] (3) Subsequently, pure phase BaCuO2 powder, pure phase Ca2CuO3 powder, B2O3 powder, and CuO powder were dry-ball milled for 2 hours at a molar ratio of B:Ba:Ca:Cu of 0.1:2:3:4. Then, a solid-state reaction was carried out at 850℃ for 24 hours. The resulting reactants were dry-ball milled for 4 hours and then subjected to a solid-state reaction at 900℃ for 24 hours. Finally, they were dry-ball milled again for 4 hours and then subjected to a solid-state reaction at 950℃ for 24 hours to obtain amorphous CuC-based copper oxide powder, such as... Figure 1 As shown in (a) above. The obtained powder was subjected to SEM testing, as shown in... Figure 2 As shown, the particle size is uniform, with a size within 10 μm, indicating that the CuC-based copper oxide powder obtained in this step has uniform particle size. This indirectly proves that the precursor is uniformly mixed, which facilitates subsequent processes.

[0056] (4) After pressing the powder obtained in step (3) onto the target, as follows: Figure 1 As shown in (b) of the diagram. Using the CuC-based copper oxide obtained in step (3) as the target material, the target after pressing was placed in a roll-to-roll PLD device to deposit a thin film on a Haseman alloy LMO substrate, ultimately obtaining a high-performance high-temperature superconducting tape. The PLD device process parameters were set as follows: oxygen pressure of 20 Pa, coating temperature of 800 °C, tension of 50 N, winding speed of 100 m / h, and laser energy density of 3 mJ / cm². 2 The obtained strip film was subjected to XRD tests, such as... Figure 3 As shown in (a), a peak with the (00l) orientation was obtained, proving the successful preparation of a CuC-based copper oxide thin film doped with element B. The surface of the obtained tape film was observed by SEM, as shown... Figure 3 As shown in (b), the film surface is uniform and has high flatness.

[0057] Example 2

[0058] A CuC-based copper oxide target and a high-temperature superconducting tape are provided, and the preparation steps are as follows:

[0059] (1) First, BaCO3 and CuO were weighed and mixed at a molar ratio of 1:0.95, dry-ball-milled for 3 hours, and then sintered at 850℃ for a solid-state reaction for 20 hours. Subsequently, the sintered material was dry-ball-milled for 3 hours, sintered at 800℃ for a solid-state reaction for 24 hours, and then dry-ball-milled again for 3 hours before sintering at 850℃ for a solid-state reaction for 24 hours. After three sintering processes, pure phase BaCuO2 powder was obtained.

[0060] (2) Next, CaCO3 and CuO were weighed and mixed at a molar ratio of 2:1, dry-milled for 3 hours, and then sintered at 850°C for 12 hours for a solid-state reaction. The sintered material was then ball-milled again for 3 hours and sintered at 900°C for 24 hours. The sintered material was then ball-milled for another 5 hours and sintered at 950°C for 24 hours. After three sintering processes, pure phase Ca2CuO3 powder was obtained.

[0061] (3) Then, pure phase BaCuO2 powder, pure phase Ca2CuO3 powder, BaSO4 and CuO powder were mixed with each other at a molar ratio of S:Ba:Ca:Cu of 0.05:2:3:4. After dry ball milling for 2 hours, the mixture was first reacted in solid phase at 850℃ for 24 hours. The resulting reactants were then dry ball milled for 4 hours and reacted in solid phase at 900℃ for 24 hours. After dry ball milling for 4 hours again, the mixture was reacted in solid phase at 950℃ for 24 hours to obtain an amorphous CuC-based copper oxide target, which is a CuC-based copper oxide target doped with B element.

[0062] (4) Using the CuC-based copper oxide obtained in step (3) as the target material, after pressing the powder obtained in step (3) into the target, the target material is placed in a roll-to-roll PLD device to deposit a thin film on a Haseman alloy CeO substrate, and finally a high-performance high-temperature superconducting tape is obtained. The PLD device process parameters are set as follows: oxygen pressure is controlled at 25 Pa, coating temperature is 820 °C, tension is 50 N, winding speed is 100 m / h, and laser energy density is 3.5 mJ / cm 2 .

[0063] Example 3

[0064] A CuC-based copper oxide target and a high-temperature superconducting tape are provided, and the preparation steps are as follows:

[0065] (1) First, BaCO3 and CuO were weighed and mixed at a molar ratio of 1:0.95, dry-ball-milled for 3 hours, and then sintered at 850℃ for a solid-state reaction for 20 hours. Subsequently, the sintered material was dry-ball-milled for 3 hours, sintered at 800℃ for a solid-state reaction for 24 hours, and then dry-ball-milled again for 3 hours before sintering at 850℃ for a solid-state reaction for 24 hours. After three sintering processes, pure phase BaCuO2 powder was obtained.

[0066] (2) Next, CaCO3 and CuO were weighed and mixed at a molar ratio of 2:1, dry-milled for 3 hours, and then sintered at 850°C for 12 hours for a solid-state reaction. The sintered material was then ball-milled again for 3 hours and sintered at 900°C for 24 hours. The sintered material was then ball-milled for another 5 hours and sintered at 950°C for 24 hours. After three sintering processes, pure phase Ca2CuO3 powder was obtained.

[0067] (3) Then, pure phase BaCuO2 powder, pure phase Ca2CuO3 powder, Al2O3 and CuO powder were mixed with Al:Ba:Ca:Cu in a molar ratio of 0.6:2:3:4. After dry ball milling for 2 hours, the mixture was first reacted in solid phase at 850℃ for 24 hours. The resulting reactants were then dry ball milled for 4 hours and reacted in solid phase at 900℃ for 24 hours. After dry ball milling for 4 hours again, the mixture was reacted in solid phase at 950℃ for 24 hours to obtain an amorphous CuC-based copper oxide target, which is a CuC-based copper oxide target doped with B element.

[0068] (4) Using the CuC-based copper oxide obtained in step (3) as the target material, after pressing the powder obtained in step (3) into the target, the target material is placed in a roll-to-roll PLD device to deposit a thin film on a Haseman alloy CeO substrate, and finally a high-performance high-temperature superconducting tape is obtained. The PLD device process parameters are set as follows: oxygen pressure is controlled at 25 Pa, coating temperature is 820 °C, tension is 50 N, winding speed is 100 m / h, and laser energy density is 3.5 mJ / cm 2 .

[0069] Example 4

[0070] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that the PLD deposition temperature is 650°C. All other steps are the same as in Example 1.

[0071] Example 5

[0072] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that the PLD deposition temperature is 950°C. All other steps are the same as in Example 1.

[0073] Example 6

[0074] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that the oxygen pressure of the PLD-deposited film is 15 Pa. The other steps are the same as in Example 1.

[0075] Example 7

[0076] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that the oxygen pressure of the PLD-deposited film is 40 Pa. The other steps are the same as in Example 1.

[0077] Example 8

[0078] A CuC-based copper oxide target and a high-temperature superconducting tape are provided, and the preparation steps are as follows:

[0079] (1) First, BaCO3 and CuO were weighed at a molar ratio of 1:1, and wet-milled for 4 hours with ethanol as the medium (ethanol:raw material was added at a mass ratio of 4:1). Then, the mixture was sintered at 850°C for 20 hours for a solid-state reaction. Subsequently, the sintered material was dry-milled for 4 hours, sintered at 850°C for 24 hours for a solid-state reaction, and then dry-milled again for 4 hours before sintering at 900°C for 24 hours for a solid-state reaction. After three sintering processes, pure phase BaCuO2 powder was obtained.

[0080] (2) Next, CaCO3 and CuO were weighed at a molar ratio of 2:1, and wet-milled with ethanol as the medium (ethanol:raw material was added at a mass ratio of 3:1) for 4 hours. Then, the mixture was sintered at 880℃ for 20 hours for a solid-state reaction. The sintered material was then ball-milled again for 3 hours and sintered at 900℃ for 24 hours. The sintered material was then ball-milled for another 5 hours and sintered at 950℃ for 24 hours. After three sintering processes, pure phase Ca2CuO3 powder was obtained.

[0081] (3) Then, pure phase BaCuO2 powder, pure phase Ca2CuO3 powder, B2O3, and CuO powder were wet-milled for 2 hours with ethanol as the medium (added at a mass ratio of ethanol:raw material = 4:1). The mixture was then subjected to a solid-phase reaction at 850℃ for 24 hours. The resulting reactants were then dry-milled for 4 hours and subjected to a solid-phase reaction at 900℃ for 24 hours. The mixture was then dry-milled again for 4 hours and subjected to a solid-phase reaction at 900℃ for 24 hours to obtain an amorphous CuC-based copper oxide target material, which is a CuC-based copper oxide target material doped with B element.

[0082] (4) Using the CuC-based copper oxide obtained in step (3) as the target material, after pressing the powder obtained in step (3) into the target, the target material is placed into a roll-to-roll PLD equipment for thin film deposition, and finally a high-performance high-temperature superconducting tape is obtained. The process parameters of the PLD equipment are set as follows: oxygen pressure is controlled at 20 Pa, coating temperature is 800 ℃, tension is 50 N, winding speed is 100 m / h, and laser energy density is 3 mJ / cm 2 .

[0083] Example 9

[0084] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as those in Example 1, except that GeO2 is added in step (3) for mixing and sintering to dope Ge elements. The other steps are the same as those in Example 1.

[0085] Example 10

[0086] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as those in Example 1, except that SeO2 is added in step (3) for mixing and sintering to dope Se. The other steps are the same as those in Example 1.

[0087] Example 11

[0088] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as those in Example 1, except that TeO2 is added in step (3) for mixing and sintering, and Te element is doped. The other steps are the same as those in Example 1.

[0089] Example 12

[0090] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as those in Example 1, except that SiO2 is added in step (3) for mixing and sintering, and Si element is doped. The other steps are the same as those in Example 1.

[0091] Example 13

[0092] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are different from those in Example 1, except that the substrate in step (4) is different. In this example, a thin film is deposited on a LAO (lanthanum aluminate LaAlO3) single crystal substrate. The other steps are the same as in Example 1.

[0093] The thin film deposition steps in this embodiment are as follows:

[0094] The CuC-based copper oxide obtained in step (3) was used as the target material. After the powder obtained in step (3) was pressed into the target, the target material was placed in a static PLD device to deposit a CuC thin film on a LAO substrate, thus obtaining a high-performance high-temperature superconducting thin film. The PLD device process parameters were set as follows: oxygen pressure of 20 Pa, temperature in the deposition chamber of 800 °C, and laser energy density of 3.0 mJ / cm². 2 .

[0095] In this embodiment, a CuC-based copper oxide target is deposited on a single-crystal substrate to form a thin film. The resulting superconducting tape is shown in the image below. Figure 4 As shown in Figure (a). The thin film deposited on the Hastelloy substrate in Example 1 is shown below. Figure 4 As shown in Figure (b).

[0096] Depositing high-temperature superconducting thin films on single-crystal substrates is commonly used to fabricate superconducting devices, such as superconducting quantum interference devices (SQUIDs) and terahertz detectors, for weak electrical applications. Depositing high-temperature superconducting thin films on Hastelloy substrates is mainly used in strong electrical applications requiring high current transmission or strong magnetic fields, such as superconducting cables, magnets, and motors. As can be seen from Example 1 and this example, the CuC-based copper oxide target material prepared by this invention has broad application prospects, as it can be used for epitaxial growth of thin films on single-crystal substrates and for deposition of thin films on the surface of Hastelloy flexible metal strips.

[0097] Comparative Example 1

[0098] This invention provides a CuC-based copper oxide target and a high-temperature superconducting tape. The preparation steps differ from those in Example 1 in that no boron (B) is doped. All other steps are the same as in Example 1. The specific preparation steps are as follows:

[0099] (1) Same as Example 1.

[0100] (2) Same as in Example 1.

[0101] (3) Then, pure phase BaCuO2 powder, pure phase Ca2CuO3 powder and CuO powder were dry ball milled for 2 hours at a molar ratio of Ba:Ca:Cu of 2:3:4. The mixture was then reacted in the solid phase at 850℃ for 24 hours. The resulting reactants were dry ball milled for 4 hours and then reacted in the solid phase at 900℃ for 24 hours. Finally, the mixture was dry ball milled for 4 hours and then reacted in the solid phase at 950℃ for 24 hours to obtain a CuC-based copper oxide target.

[0102] (4) Using the CuC-based copper oxide obtained in step (3) as the target material, after pressing the powder obtained in step (3) into the target, the target material is placed in a roll-to-roll PLD device to deposit a thin film on a Haseman alloy CeO substrate, and finally a high-temperature superconducting tape is obtained. The PLD device process parameters are set as follows: oxygen pressure is controlled at 20 Pa, coating temperature is 800 ℃, tension is 50 N, winding speed is 100 m / h, and laser energy density is 3 mJ / cm 2 .

[0103] Comparative Example 2

[0104] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that the preparation of precursors in steps (1) and (2) is omitted, and all raw materials are mixed at once for solid-state reaction. Other steps are the same as in Example 1. The specific preparation steps are as follows:

[0105] (1) BaCO3 powder, CuO powder, CaCO3 powder and B2O3 were mixed in a molar ratio of B:Ba:Ca:Cu of 0.1:2:3:4. After dry ball milling for 2 hours, the mixture was first reacted in solid phase at 850℃ for 24 hours. The resulting reactant was then dry ball milled for 4 hours and reacted in solid phase at 900℃ for 24 hours. After dry ball milling for 4 hours again, the mixture was reacted in solid phase at 950℃ for 24 hours to obtain a CuC-based copper oxide target material, which is a CuC-based copper oxide target material doped with B element.

[0106] (2) The obtained CuC-based copper oxide was used as a target for thin film deposition. The thin film deposition method was the same as in Example 1: the obtained CuC-based copper oxide powder was pressed into a target, and then the target was placed in a roll-to-roll PLD equipment to deposit a thin film on a Haseman alloy CeO substrate. The PLD equipment process parameters were set as follows: oxygen pressure of 20 Pa, coating temperature of 800 °C, tension of 50 N, winding speed of 100 m / h, and laser energy density of 3 mJ / cm². 2 Ultimately, a high-temperature superconducting tape was obtained.

[0107] Comparative Example 3

[0108] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that step (1) of preparing pure-phase BaCuO2 powder is not performed, and the Ba raw material and B element doping are carried out in one step. The other steps are the same as in Example 1. The specific preparation steps are as follows:

[0109] (1) CaCO3 and CuO were weighed and mixed at a molar ratio of 2:1, dry-milled for 4 hours, and then sintered at 880℃ for 20 hours for a solid-state reaction. The sintered material was then ball-milled again for 3 hours and sintered at 900℃ for 24 hours. The sintered material was then ball-milled for another 5 hours and sintered at 950℃ for 24 hours. After three sintering processes, pure phase Ca2CuO3 powder was obtained.

[0110] (2) Then, BaCO3 powder, CuO powder, pure phase Ca2CuO3 powder and B2O3 are mixed in a molar ratio of B:Ba:Ca:Cu of 0.1:2:3:4. After dry ball milling for 2 hours, the mixture is first reacted in solid phase at 850℃ for 24 hours. The resulting reactant is then dry ball milled for 4 hours and reacted in solid phase at 900℃ for 24 hours. After dry ball milling for 4 hours again, the mixture is reacted in solid phase at 950℃ for 24 hours to obtain a CuC-based copper oxide target material, which is a CuC-based copper oxide target material doped with B element.

[0111] (3) The obtained CuC-based copper oxide was used as a target material for thin film deposition. The thin film deposition method was the same as in Example 1: the obtained CuC-based copper oxide powder was pressed into a target, and then the target material was placed in a roll-to-roll PLD equipment to deposit a thin film on a Haseman alloy CeO substrate. The PLD equipment process parameters were set as follows: oxygen pressure of 20 Pa, coating temperature of 800 °C, tension of 50 N, winding speed of 100 m / h, and laser energy density of 3 mJ / cm². 2 Ultimately, a high-temperature superconducting tape was obtained.

[0112] Comparative Example 4

[0113] A CuC-based copper oxide target and a high-temperature superconducting tape are provided. The preparation steps are the same as in Example 1, except that step (2) of preparing pure-phase Ca2CuO3 powder is not performed, and Ca raw material and B element doping are carried out in one step. Other steps are the same as in Example 1. The specific preparation steps are as follows:

[0114] (1) BaCO3 and CuO were weighed and mixed at a molar ratio of 1:1, dry-ball-milled for 4 hours, and then sintered at 850℃ for a solid-state reaction for 20 hours. Subsequently, the sintered material was dry-ball-milled for 4 hours, sintered at 850℃ for a solid-state reaction for 24 hours, and then dry-ball-milled again for 4 hours before sintering at 900℃ for a solid-state reaction for 24 hours. After three sintering processes, pure phase BaCuO2 powder was obtained.

[0115] (2) Then, pure phase BaCuO2 powder, CuO powder, CaCO3 powder and B2O3 were mixed in a molar ratio of B:Ba:Ca:Cu of 0.1:2:3:4. After dry ball milling for 2 hours, the mixture was first reacted in solid phase at 850℃ for 24 hours. The resulting reactant was dry ball milled for 4 hours and then reacted in solid phase at 900℃ for 24 hours. After dry ball milling for 4 hours again, the mixture was reacted in solid phase at 950℃ for 24 hours to obtain a CuC-based copper oxide target material, which is a CuC-based copper oxide target material doped with B element.

[0116] (3) The obtained CuC-based copper oxide was used as a target material for thin film deposition. The thin film deposition method was the same as in Example 1: the obtained CuC-based copper oxide powder was pressed into a target, and then the target material was placed in a roll-to-roll PLD equipment to deposit a thin film on a Haseman alloy CeO substrate. The PLD equipment process parameters were set as follows: oxygen pressure of 20 Pa, coating temperature of 800 °C, tension of 50 N, winding speed of 100 m / h, and laser energy density of 3 mJ / cm². 2 Ultimately, a high-temperature superconducting tape was obtained.

[0117] Performance Characterization

[0118] The initial transition temperature (T) is defined as 90% of the film resistance becoming the normal resistance.onset c When the thin film resistance temperature is zero, that is, the superconducting transition temperature (T0). zero c The resistance-temperature curves of the superconducting thin films obtained in Examples 1 to 13 and Comparative Examples 1 to 4 were tested, and the results are shown in [Figure 1]. Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 .

[0119] Figure 5 The graphs show the resistance-temperature variation of the superconducting thin films prepared in Examples 1 to 3. Figure 6 The figures show the resistance-temperature curves of the superconducting thin films prepared in Examples 4 and 5. Figure 7 The figures show the resistance-temperature curves for Examples 6, 7, and 8. (From...) Figure 1 As can be seen, the T of the thin film doped with 0.1 moles of B element in Example 1 onset c For 113K, T zero c It is 95.2K, by Figure 3 As shown in Figure (a), the (00l) oriented peaks demonstrate the successful preparation of the B-doped CuC-based copper oxide thin film. Example 2 was doped with 0.05 moles of S, and its thin film T... onset c For 112K, T zero c The K value is 96.4 K; Example 3 was doped with 0.6 moles of Al, and its thin film T onset c For 112K, T zero c The K value is 97.5 K. Thin films with good superconducting properties were prepared in Examples 1-3, and their performance did not degrade after 6 months of storage.

[0120] Depend on Figure 6 and Figure 7 As can be seen, the thin film T in Example 4 zero c The K value is 96.5 K. Example 5 Thin Film T zero c The K value is 93.2 K. Example 6 Thin Film T zero c The K value is 93.7 K. Example 7 Thin Film T zero c The K value is 98.5 K. Example 8 Thin Film T zero cThe K value is 101.8 K. Compared to Example 1, Examples 4 and 5, with different film deposition temperatures of 650°C and 950°C respectively, and Examples 6 and 7, with different film deposition oxygen pressures of 15 Pa and 40 Pa respectively, all maintained excellent superconducting properties. This demonstrates that the superconducting properties of the films prepared by this invention with different doping elements (Cu) are all at a superior level. x M y C 1-x-y Ba2Ca3Cu4O 11+δ (M is selected from B, Al, Si, Ge, S, Se, Te) It has the characteristics of a large process temperature window and a large process oxygen pressure window. In Example 8, the superconducting data measured is the best among all examples. This may be because the optimized target preparation method in Example 8 is most conducive to the epitaxial growth of the thin film. This shows that the doped element target of the present invention has a high prospect threshold and is expected to produce a superconducting transition temperature of 120K that is closer to that of Cu-1234 material.

[0121] Figure 8 The figures shown are resistance-temperature curves for the thin films of Examples 9-13. Compared to Example 1, Examples 9-12 are superconducting thin films doped with different elements. The resistance-temperature curves for the thin film of Example 9 are shown. zero c The K value is 94.5 K. Example 10 Thin Film T zero c The K value is 92.3 K. Example 11 Thin Film T zero c The K value is 95.2 K. Example 12 Thin Film T zero c The temperature was 94.5 K, demonstrating that this invention achieved the fabrication of thin films with relatively high superconducting transition temperatures under different doping conditions. Example 13: Thin film T deposited on a single-crystal substrate. zero c The K value is 103 K. Therefore, it can be seen that even when a thin film is deposited on a soft substrate in Embodiment 1 of the present invention, its superconducting properties are quite close to those of a single-crystal hard substrate (T0). zero c (95K), After optimizing the preparation method in Example 8, the superconducting transition temperature of the thin film deposited on the soft substrate is comparable to that in Example 13, which demonstrates the superiority of the method of the present invention from another perspective.

[0122] Figure 9 The figures shown are the resistance-temperature curves of the thin films in Comparative Examples 1-4. Figure 9 As can be seen, the performance degrades when CuC-based copper oxide targets are prepared without boron doping or by mixing all raw materials at once, as shown in Comparative Examples 1 to 4. Comparative Example 1: Thin Film T zero c The K value is 81.2 K, and the comparative example 2 thin film T is... zeroc The K value is 78.8 K, and the comparative example 3 thin film T zero c The K value is 82.7 K, and the comparative example 4 thin film T zero c It is 80.3K.

[0123] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0124] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A CuC-based copper oxide high-temperature superconducting material, characterized in that: The chemical formula of the CuC-based copper oxide is (Cu x M y C 1-x-y Ba2Ca3Cu4O 11+δ M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, and 0.1≤x≤0.9, 0<y≤1.

2. The preparation method of CuC-based copper oxide high-temperature superconducting material as described in claim 1, characterized in that: The target material of the CuC-based copper oxide high-temperature superconducting material is prepared by any one of the following methods: solid-state sintering, sol-gel method, and precipitation method.

3. A method for preparing a CuC-based copper oxide high-temperature superconducting material, characterized in that: Includes the following steps: Step S1: Synthesize pure-phase BaCuO2 precursor; Step S2: Synthesize pure-phase Ca2CuO3 precursor; Step S3: According to the molar ratio of M:Ba:Ca:Cu of y:2:3:4, the compound containing element M is mixed with BaCuO2 precursor, Ca2CuO3 precursor and CuO by ball milling, and then subjected to high temperature sintering and ball milling in sequence. The high temperature sintering and ball milling are repeated several times to obtain a CuC-based copper oxide high temperature superconducting material. in: The element M is selected from at least one of B, Al, Si, Ge, S, Se, and Te, where 0 < y ≤ 1.

4. The preparation method according to claim 3, characterized in that: In step S3, the compound containing element M is selected from oxides of M, MO. 2- MO3 2- MO 3- MO4 2- or MO4 4- with Ba 2+ Ca 2+ At least one of the compounds that make up the composition.

5. The preparation method according to claim 3 or 4, characterized in that: In step S3, M is selected from one or more of the following substances: B2O3, Al2O3, SiO3, GeO3, SO3, SO3, SeO3, TeO2, TeO, Ca3(BO3)2, Ba3(BO3)2, CaB4O7·4H2O, BaB4O7, Ca( BO2)3, Ba(BO3)3, Ca[Al(OH)4]5, Ba[Al(OH)4]2, CaAl2O4, BaAl2O4, CaSiO3, BaSiO3, Ca2SiO4, Ba2SiO4 , Ca2Si2O5, Ba2Si2O5, CaGeO3, BaGeO3, CaSO4·2H2O, CaSO4·0.5H2O, BaSO4, CaSO3·0.5H2O, BaSO3, CaS 2O3, BaS2O3, CaS2O8, BaS2O8, CaSeO4·2H2O, BaSeO4, CaSeO3, BaSeO3, CaTeO4, BaTeO4, CaTeO3, BaTeO3.

6. The preparation method according to claim 3, characterized in that: In step S3, the high-temperature sintering temperature is 850~950℃, the sintering time is 10~50 hours, and the ball milling treatment time is 1~100 hours.

7. The preparation method according to claim 3, characterized in that: In step S1, the method for synthesizing the pure phase BaCuO2 precursor is as follows: barium carbonate powder and copper oxide powder are ball-milled at a molar ratio of 1:0.9~1, followed by high-temperature sintering and ball milling; the high-temperature sintering and ball milling are repeated several times to obtain the pure phase BaCuO2 precursor.

8. The preparation method according to claim 3, characterized in that: In step S2, the method for synthesizing the pure phase Ca2CuO3 precursor is as follows: calcium carbonate powder and copper oxide powder are ball-milled at a molar ratio of 1:1 to 1.2, followed by high-temperature sintering and ball milling; the high-temperature sintering and ball milling are repeated several times to obtain the pure phase Ca2CuO3 precursor.

9. The application of the CuC-based copper oxide high-temperature superconducting material as described in claim 1 or the CuC-based copper oxide prepared by the preparation method as described in any one of claims 3 to 8 in the preparation of superconducting thin films.

10. A method for preparing a high-temperature superconducting tape, characterized in that: Includes the following steps: Using CuC-based copper oxide as described in claim 1 as the target material, or using CuC-based copper oxide prepared by any one of the preparation methods described in claims 3 to 8 as the target material, a superconducting thin film is deposited on the substrate using pulsed laser deposition technology.

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