A method for preparing infinite-layer nickel-based superconducting thin films by MOCVD

Abstract

This invention provides a method for preparing infinite-layer nickel-based superconducting thin films using metal-organic chemical vapor deposition (MOCVD). The main concept involves dissolving a soluble metal cation precursor in a solvent at a stoichiometric ratio, forming a thin film precursor on a single-crystal perovskite oxide substrate via MOCVD; subsequently, annealing under a high-oxygen-pressure atmosphere yields a thermodynamically metastable perovskite intermediate; finally, reduction conditions are used to transform it into an infinite-layer nickel-based superconducting thin film. The advantages of this method include low cost, suitability for large-scale, large-area preparation of superconducting thin films, flexible control of film composition, and high reproducibility. The superconducting thin films prepared using this method exhibit zero resistance below 20 K and at ambient pressure, promising to promote the large-scale application of nickel-based superconducting materials in superconducting wires and tapes and in electronics, including high-field magnet coils, high-frequency low-loss cables, superconducting computers, superconducting antennas, and superconducting microwave devices.

Description

Technical Field

[0001] This invention belongs to the field of functional materials and relates to a method for preparing infinite-layer nickel-based superconducting thin films by MOCVD. Background Technology

[0002] High-temperature superconducting materials have wide applications in many fields, including strong-field magnet coils, high-frequency low-loss cables, quantum computing, high-frequency sensors, microwave devices, and communications, and can profoundly change human society. This development began with the discovery of high-temperature superconductivity in copper oxides. [1] To this day, elucidating the physical mechanisms of high-temperature superconductivity and searching for superconductors with even higher superconducting critical transition temperatures, even those on the order of room temperature, remain the goals of scientists. In 2019, Li et al. [2] Successfully prepared infinite-layer Nd 1- x Sr x NiO2 superconducting thin films. The method mainly includes thin film growth and post-annealing treatment: 1) Ni oxide thin films of phase 113 are prepared by pulsed laser deposition; 2) Ni oxide superconducting thin films of phase 112 infinite layer nickelate are prepared by CaH2 soft chemical treatment.

[0003] The discovery of infinite-layer nickel-based superconducting materials (chemical formula RNiO2, where R represents a rare earth element) caused a great sensation, pointing to a new direction for the advent of the nickel superconducting era. In particular, the parent material RNiO2 of infinite-layer nickel-based superconductors has a similar crystal structure to CaCuO2, one of the parent materials of copper oxide high-temperature superconductors, and their outermost electron configurations (3d2) are similar. 9 Similar to the parent compounds of many copper oxide superconductors, nickel-based superconductors exhibit excellent diamagnetic properties under magnetic fields. In particular, superconductivity exceeding the McMillan limit (40 K) at ambient pressure has recently been achieved in infinitely layered nickel-based superconducting thin films. [3] This opens up new avenues for utilizing its diamagnetic properties under more practical conditions in the future. Therefore, in-depth exploration and research on related nickel oxides can not only help to further understand the physical origin of unconventional high-temperature superconductivity, but also promises to enable the large-scale application of nickel-based superconducting materials in superconducting wires and ribbons and electronics. However, to date, no infinitely layered nickel-based superconducting bulk samples have been fabricated.

[0004] To further investigate the mechanism of infinite-layer nickel-based superconductivity and promote its practical applications, the preparation of high-quality, large-area nickel-based superconducting thin films is of paramount importance. Currently, the preparation of infinite-layer nickel oxide thin films mainly employs pulsed laser deposition (PLD), molecular beam epitaxy (OMBE), and magnetron sputtering. However, these methods suffer from narrow deposition windows, slow growth rates, low yields, and high preparation costs, making sample preparation challenging and resulting in relatively slow experimental progress.

[0005] To address the aforementioned technical problems, this invention proposes a method for preparing infinite-layer nickel-based superconducting thin films using MOCVD technology. Studies have shown that this method is low-cost, simple, and feasible.

[0006] References

[0007] [1] JG Bednorz and KA Muller, Possible high Tc superconductivity in the Ba-La-Cu-O system, Z. Phys. B 1986, 64: 189.

[0008] [2] D. Li, K. Lee, BY Wang, M. Osada, S. Crossley, HR Lee, Y.Cui, Y. Hikita, HY Hwang, Superconductivity in an infinite-layernickelate, Nature 2019, 572: 624.

[0009] [3] SLE Chow, ZY Luo, A. Ariando, Bulk superconductivity near 40K in hole-doped SmNiO2 at ambient pressure, Nature 2025, 642: 58. Summary of the Invention

[0010] The purpose of this invention is to provide a low-cost, large-area method for fabricating infinitely layered nickel-based superconducting thin films using MOCVD technology. The method is characterized by the following main steps:

[0011] ① Deposition: Perovskite nickel oxide thin films are grown on single-crystal substrates using MOCVD. Specifically, various metal-organic sources are mixed in an organic solvent according to a designed ratio, heated to 60-100 °C, and stirred until completely dissolved. The solution is then cooled to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution is fed sequentially via a precisely controlled injection pump, flash-evaporated at 150-350 °C, and then introduced into the reaction chamber with a carrier gas (Ar / N2). Finally, a 113-phase perovskite nickel oxide thin film is thermally deposited and grown on the single-crystal substrate.

[0012] ② CaH2 reduction: The grown perovskite nickel oxide film is loosely wrapped with aluminum foil, then embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace where the pressure reaches 10. -5~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0013] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of nickel (Ni) and other metals (Sr, Nd, La, Pr, Sm, Eu, Gd, Dy), whose chemical formula includes: M(R). x (L) y Where: M is a metal Ni, Sr, Nd, La, Pr, Sm, Eu, Gd, or Dy; R is a β-diketone organic ligand; L is a polydentate ether or a nitrogen-containing organic ligand, and x and y are integers, where x + y equals the maximum coordination number of the metal.

[0014] The β-diketone organic ligands are selected from: 2,2,6,6-Tetramethyl-3,5-heptanedione (tmhd), 1,1,1,5,5,5-Hexafluoroacetylacetone (hfac), 2,2-Dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione (dmhfod), Dibenzoylmethane (dbm), and Hexafluoroacetylacetone (hfac).

[0015] Among them, the polydentate ether organic ligands are selected from: CH3OCH2CH2OCH3, CH3O(CH2CH2O)2CH3, CH3O(CH2CH2O)3CH3 and CH3O(CH2CH2O)4CH3.

[0016] The nitrogen-containing organic ligands are selected from: 2,2-Bipyridine (bipy), 1,10-Phenanthroline (phen), Bathophenanthroline (batho), Neocoproine (neo), and 3,4,7,8-Tetramethyl-1,10-phenanthroline (tmphen).

[0017] The organic solvents are selected from: toluene, tetrahydrofuran (THF), monoethylene glycol, diethylene glycol, tetraethylene glycol, isopropanol, and 2-methoxy-2-methylpropanol.

[0018] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of R. 1-x Sr xNiO3 (R=Nd,La, Pr, Sm, Eu, Gd, Dy, etc.; 0.1 <x<0.3)。

[0019] In step ①, the thickness of the perovskite nickel oxide film is controlled between 5 and 30 nm.

[0020] In step ①, the single crystal substrate is a material such as SrTiO3(100).

[0021] In step ①, the substrate temperature is 400-900 ℃ during the deposition of the perovskite nickel oxide thin film.

[0022] In step ①, the gas pressure range during the deposition of the perovskite nickel oxide thin film is 50-760. Torr.

[0023] In step ②, the annealing temperature range is 200-400 ℃.

[0024] In step ②, the annealing time is 0.5-6 hours, and after annealing, it is directly cooled to room temperature within 30-60 minutes.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention proposes a simple and feasible experimental method for preparing infinite-layer nickel-based superconducting thin films, enabling large-area and rapid growth of such films. Compared with conventional methods for preparing infinite-layer superconducting thin films, this method offers faster growth rates, higher yields, and lower costs. The superconducting thin films prepared using this method exhibit zero resistance below 20 K and under ambient pressure, such as... Figure 1 and Figure 2 As shown. This invention is expected to enable the large-scale application of nickel-based superconducting materials in superconducting wires and tapes and in the field of electronics, including high-field magnet coils, high-frequency low-loss cables, superconducting computers, superconducting antennas, and superconducting microwave devices. Attached Figure Description

[0028] Figure 1 . Nd 0.8 Sr 0.2 Plot of the relationship between the bulk resistance of NiO2 superconducting thin films under zero magnetic field and temperature dependence.

[0029] Figure 2 La 0.8 Sr 0.2 Plot of the relationship between the bulk resistance of NiO2 superconducting thin films under zero magnetic field and temperature dependence. Detailed Implementation

[0031] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing Nd using MOCVD technology 0.8 Sr 0.2 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0034] ① Deposition: Nd2+ is grown on a single-crystal substrate using MOCVD. 0.8 Sr 0.2 NiO3 perovskite nickel oxide thin films were obtained by mixing Ni, Nd, and Sr metal-organic sources in a designed ratio (1:0.8:0.2) in the organic solvent toluene, heating to 80 °C and stirring until completely dissolved, and then cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed through an injection pump, flashed at 180 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0035] ② CaH2 reduction: The grown perovskite nickel oxide film is loosely wrapped with aluminum foil, then embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace where the pressure reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0036] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Nd, with the chemical formulas Ni(tmhd)2(phen), Sr(tmhd)3, and Nd(tmhd)3(CH3O(CH2CH2O)2CH3), respectively.

[0037] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Nd. 0.8 Sr 0.2 NiO3.

[0038] In step ①, the thickness of the perovskite nickel oxide film is controlled at 10 nm.

[0039] In step ①, the single crystal substrate is SrTiO3(100).

[0040] In step ①, the substrate temperature is 600 °C during the deposition of the perovskite nickel oxide thin film.

[0041] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 600. Torr.

[0042] In step ②, the annealing temperature range is 320 °C.

[0043] In step ②, the annealing time is 3 hours, and after annealing, it is directly cooled to room temperature within 40 minutes.

[0044] Example 2

[0045] A method for preparing La using MOCVD technology 0.8 Sr 0.2 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0046] ①Deposition: La is grown on a single-crystal substrate using MOCVD. 0.8 Sr 0.2 NiO3 perovskite nickel oxide thin films were obtained by mixing Ni, La, and Sr metal-organic sources in a designed ratio (1:0.8:0.2) in the organic solvent diethylene glycol, heating to 80 °C and stirring until completely dissolved, and then cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed through an injection pump, flashed at 180 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0047] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0048] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and La, with the chemical formulas Ni(tmhd)2(CH3OCH2CH2OCH3), Sr(tmhd)3, and La(tmhd)3(CH3O(CH2CH2O)2CH3), respectively.

[0049] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of La. 0.8 Sr 0.2 NiO3.

[0050] In step ①, the thickness of the perovskite nickel oxide film is controlled at 10 nm.

[0051] In step ①, the single crystal substrate is SrTiO3(100).

[0052] In step ①, the substrate temperature is 750 °C during the deposition of the perovskite nickel oxide thin film.

[0053] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 100. Torr.

[0054] In step ②, the annealing temperature range is 320 °C.

[0055] In step ②, the annealing time is 3 hours, and after annealing, it is directly cooled to room temperature within 40 minutes.

[0056] Example 3

[0057] A method for preparing Pr using MOCVD technology 0.85 Sr 0.15 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0058] ①Deposition: Pr is grown on a single-crystal substrate using MOCVD. 0.85 Sr 0.15 NiO3 perovskite nickel oxide thin films were obtained by mixing Ni, Pr, and Sr metal-organic sources in a designed ratio (1:0.85:0.15) in tetrahydrofuran, heating to 60 °C and stirring until completely dissolved, and then cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed through an injection pump, flashed at 200 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0059] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0060] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Pr, with the chemical formulas Ni(tmhd)2(phen), Sr(tmhd)3 and Pr(tmhd)3(tmphen), respectively.

[0061] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Pr. 0.85 Sr 0.15NiO3.

[0062] In step ①, the thickness of the perovskite nickel oxide film is controlled at 10 nm.

[0063] In step ①, the single crystal substrate is SrTiO3(100).

[0064] In step ①, the substrate temperature is 750 °C during the deposition of the perovskite nickel oxide thin film.

[0065] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 600. Torr.

[0066] In step ②, the annealing temperature range is 300 °C.

[0067] In step ②, the annealing time is 2 hours, and after annealing, the material is cooled directly to room temperature within 30 minutes.

[0068] Example 4

[0069] A method for preparing Sm using MOCVD technology 0.75 Sr 0.25 A method for producing an infinitely layered nickel-based superconducting thin film using NiO2, characterized by comprising the following steps:

[0070] ①Deposition: Sm is grown on a single-crystal substrate using MOCVD. 0.75 Sr 0.25 NiO3 perovskite nickel oxide thin films were obtained by mixing Ni, Sm, and Sr metal-organic sources in a designed ratio (1:0.75:0.25) in 2-methoxy-2-methylpropanol, heating to 60 °C and stirring until completely dissolved, followed by cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed through an injection pump, flash-evaporated at 300 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0071] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0072] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Sm, with the chemical formulas Ni(tmhd)2, Sr(tmhd)3(CH3O(CH2CH2O)4CH3), and Sm(tmhd)3(tmphen), respectively.

[0073] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Sm 0.75 Sr 0.25 NiO3.

[0074] In step ①, the thickness of the perovskite nickel oxide film is controlled at 15 nm.

[0075] In step ①, the single crystal substrate is SrTiO3(100).

[0076] In step ①, the substrate temperature is 550 °C during the deposition of the perovskite nickel oxide thin film.

[0077] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 500. Torr.

[0078] In step ②, the annealing temperature range is 300 °C.

[0079] In step ②, the annealing time is 6 hours, and after annealing, it is directly cooled to room temperature within 60 minutes.

[0080] Example 5

[0081] A method for preparing Eu using MOCVD technology 0.9 Sr 0.1 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0082] ①Deposition: Eu is grown on a single-crystal substrate using MOCVD. 0.9 Sr 0.1 NiO3 perovskite nickel oxide thin films were prepared by mixing Ni, Eu, and Sr metal-organic sources in a designed ratio (1:0.9:0.1) in 2-methoxy-2-methylpropanol, heating to 80 °C and stirring until completely dissolved, followed by cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed via an injection pump, flash-evaporated at 300 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0083] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10.-5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0084] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Eu, with the chemical formulas Ni(tmhd)2, Sr(tmhd)3(CH3O(CH2CH2O)4CH3), and Eu(tmhd)3, respectively.

[0085] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Eu. 0.9 Sr 0.1 NiO3.

[0086] In step ①, the thickness of the perovskite nickel oxide film is controlled at 20 nm.

[0087] In step ①, the single crystal substrate is SrTiO3(100).

[0088] In step ①, the substrate temperature is 500 °C during the deposition of the perovskite nickel oxide thin film.

[0089] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 600. Torr.

[0090] In step ②, the annealing temperature range is 300 °C.

[0091] In step ②, the annealing time is 6 hours, and after annealing, it is directly cooled to room temperature within 60 minutes.

[0092] Example 6

[0093] A method for preparing Gd using MOCVD technology 0.8 Sr 0.2 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0094] ①Deposition: Gd is grown on a single-crystal substrate using MOCVD. 0.8 Sr 0.2 NiO3 perovskite nickel oxide thin films were prepared by mixing Ni, Gd, and Sr metal-organic sources in a designed ratio (1:0.8:0.2) in isopropanol, heating to 100 °C and stirring until completely dissolved, followed by cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed via an injection pump, flash-evaporated at 350 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0095] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0096] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Gd, with the chemical formulas Ni(tmhd)2, Sr(tmhd)3(tmphen) and Gd(tmhd)3(CH3O(CH2CH2O)4CH3), respectively.

[0097] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Gd. 0.8 Sr 0.2 NiO3.

[0098] In step ①, the thickness of the perovskite nickel oxide film is controlled at 30 nm.

[0099] In step ①, the single crystal substrate is SrTiO3(100).

[0100] In step ①, the substrate temperature is 500 °C during the deposition of the perovskite nickel oxide thin film.

[0101] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 600. Torr.

[0102] In step ②, the annealing temperature range is 320 °C.

[0103] In step ②, the annealing time is 1 hour, and after annealing, it is directly cooled to room temperature within 40 minutes.

[0104] Example 7

[0105] A method for preparing Dy using MOCVD technology 0.78 Sr 0.22 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0106] ①Deposition: Dy is grown on a single-crystal substrate using MOCVD. 0.78 Sr 0.22NiO3 perovskite nickel oxide thin films were obtained by mixing Ni, Dy, and Sr metal-organic sources in a designed ratio (1:0.78:0.22) in tetraethylene glycol, heating to 60 °C and stirring until completely dissolved, followed by cooling to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution was precisely fed via an injection pump, flash-evaporated at 250 °C, and then introduced into the reaction chamber with argon gas, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on a single-crystal substrate.

[0107] ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased to perform reduction annealing on the sample, resulting in an infinite-layer nickel-based superconducting thin film with 112 phases.

[0108] In step ①, the metal-organic source used in the MOCVD process is a metal coordination compound of Ni, Sr and Dy, with the chemical formulas Ni(tmhd)2(CH3O(CH2CH2O)2CH3), Sr(tmhd)3(neo), and Dy(tmhd)3(batho), respectively.

[0109] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of Dy. 0.78 Sr 0.22 NiO3.

[0110] In step ①, the thickness of the perovskite nickel oxide film is controlled at 15 nm.

[0111] In step ①, the single crystal substrate is SrTiO3(100).

[0112] In step ①, the substrate temperature is 500 °C during the deposition of the perovskite nickel oxide thin film.

[0113] In step ①, the gas pressure during the deposition of the perovskite nickel oxide thin film is 600. Torr.

[0114] In step ②, the annealing temperature range is 300 °C.

[0115] In step ②, the annealing time is 4 hours, and after annealing, it is directly cooled to room temperature within 30 minutes.

Claims

1. A method for preparing infinite-layer nickel-based superconducting thin films using metal-organic chemical vapor deposition (MOCVD) technology. Characterized by, The chemical composition of the infinite layer nickel-based superconducting thin film is R 1-x Sr x NiO2 (rare earth element R = Nd, La, Pr, Sm, Eu, Gd, Dy, etc.; 0.1 < x < 0.3). The preparation method comprises the following steps: ① Deposition: Perovskite nickel oxide thin films are grown on single-crystal substrates using MOCVD. Specifically, various metal-organic sources are mixed in an organic solvent according to a designed ratio, heated to 60-100 °C, and stirred until completely dissolved. The solution is then cooled to room temperature to obtain a mixed metal-organic source solution. Subsequently, the solution is precisely fed through an injection pump, flash-evaporated at 100-350 °C, and then introduced into the reaction chamber with a carrier gas (Ar / N2). Finally, a 113-phase perovskite nickel oxide thin film R is thermally deposited and grown on the single-crystal substrate. 1- x Sr x NiO3; ② CaH2 reduction: After the perovskite nickel oxide film has been grown, it is loosely wrapped with aluminum foil, embedded in a glass boat containing CaH2 powder, and then placed in a tube furnace. The pressure in the furnace reaches 10. -5 ~10 -1 After torsion, the temperature was increased, and the sample was subjected to reduction annealing to obtain an infinite-layer nickel-based superconducting thin film R with 112 phase. 1-x Sr x NiO2.

2. The method for preparing infinite-layer nickel-based superconducting thin films using MOCVD technology as described in claim 1, wherein the metal-organic source used in the MOCVD process in step ① is a metal coordination compound of nickel (Ni) and other metals (Sr, Nd, La, Pr, Sm, Eu, Gd, Dy), and its chemical formula includes: M(R) x (L) y Where: M is a metal Ni, Sr, Nd, La, Pr, Sm, Eu, Gd, or Dy; R is a β-diketone organic ligand; L is a polydentate ether or a nitrogen-containing organic ligand, and x and y are integers, where x + y equals the maximum coordination number of the metal.

3. The preparation method according to claim 1, wherein the β-diketone organic ligand used in the MOCVD process in step ① is selected from: 2,2,6,6-Tetramethyl-3,5-heptanedione (tmhd), 1,1,1,5,5,5-Hexafluoroacetylacetone (hfac), 2,2-Dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione (dmhfod), Dibenzoylmethane (dbm), and Hexafluoroacetylacetone (hfac).

4. The preparation method according to claim 1, wherein the polydentate ether organic ligand used in the MOCVD process in step ① is selected from: CH3OCH2CH2OCH3, CH3O(CH2CH2O)2CH3, CH3O(CH2CH2O)3CH3 and CH3O(CH2CH2O)4CH3.

5. The preparation method according to claim 1, wherein the nitrogen organic ligand used in the MOCVD process in step ① is selected from: 2,2-bipyridine (bipy), 1,10-Phenanthroline (phen), Bathophenanthroline (batho), Neocoproine (neo), 3,4,7,8-Tetramethyl-1,10-phenanthroline (tmphen).

6. The preparation method according to claim 1, wherein the organic solvent used in the MOCVD process in step ① is selected from: toluene, tetrahydrofuran (THF), monoethylene glycol, diethylene glycol, tetraethylene glycol, isopropanol, and 2-methoxy-2-methylpropanol.

7. The preparation method according to claim 1, wherein in step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of R. 1-x Sr x NiO3 (R=Nd, La, Pr, Sm, Eu, Gd, Dy, etc.; 0.1 <x<0.3)。 8. The preparation method according to claim 1, wherein in step ①, the thickness of the perovskite nickel oxide film is controlled to be 5–30 nm.

9. The preparation method according to claim 1, wherein in step ①, the single crystal substrate is a material such as SrTiO3(100).

10. The preparation method according to claim 1, wherein in step ①, the substrate temperature is 400-900 °C during the deposition of the perovskite nickel oxide thin film.

11. The preparation method according to claim 1, wherein in step ①, the gas pressure range during the deposition of the perovskite nickel oxide thin film is 50-760 Torr.

12. The preparation method according to claim 1, wherein in step ②, the annealing temperature range is 200-400 °C.

13. The preparation method according to claim 1, wherein in step ②, the annealing time is 0.5-6 hours, and after annealing, the material is directly cooled to room temperature within 30-60 minutes.

Images