A MOD preparation method for infinitely layered nickel-based superconducting thin films

Abstract

This invention provides a metal-organic deposition (MOD) method for preparing infinite-layer nickel-based superconducting thin films. 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 metal-organic salt deposition; subsequently, annealing under an 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 are low cost, simplicity, ease of implementation, flexible control of film composition, and high reproducibility. The superconducting thin film prepared using this method exhibits 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 MOD (Multilayer Diode) of infinitely layered nickel-based superconducting thin films. 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 MOD 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, simple, and feasible method for preparing infinitely layered nickel-based superconducting thin films using MOD (Modular Deposition) 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 the MOD method. 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. A thin film is formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film is thermally deposited and grown on the single-crystal substrate.

[0012] 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.

[0013] In step ①, the metal-organic source used in the MOD 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 x NiO3 (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 20 nm.

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

[0021] In step ①, the annealing temperature is 500-900 ℃.

[0022] In step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 0.1-100 MPa.

[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 The resistivity of NiO2 superconducting thin films as a function of temperature under zero magnetic field.

[0029] Figure 2 La 0.8 Sr 0.2 Resistivity versus temperature dependence of NiO2 superconducting thin films under zero magnetic field. 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 MOD 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 the MOD method. 0.8 Sr 0.2 NiO3 perovskite nickel oxide thin films. Specifically, a metal-organic source of Ni, Nd, and Sr is mixed in a designed ratio (1:0.8:0.2) in the organic solvent toluene, heated to 80 °C, and stirred until completely dissolved. The solution is then cooled to room temperature to obtain a mixed metal-organic source solution. A thin film is formed on a single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film is thermally deposited and grown on the single-crystal substrate.

[0035] 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.

[0036] In step ①, the metal-organic source used in the MOD 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 annealing temperature is 600 ℃.

[0041] In step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 20 MPa.

[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 MOD 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 the MOD method. 0.8 Sr 0.2 NiO3 perovskite nickel oxide thin films are produced 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, then cooling to room temperature to obtain a mixed metal-organic source solution. A thin film is formed on a single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on the 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 organometallic source used in the MOD 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 annealing temperature is 700 °C.

[0053] In step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 10 MPa.

[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 MOD 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 the MOD method. 0.85 Sr 0.15 NiO3 perovskite nickel oxide thin films are produced 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, then cooling to room temperature to obtain a mixed metal-organic source solution. A thin film is formed on a single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on the 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 MOD 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 0.15 NiO3.

[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 annealing temperature is 750 °C.

[0065] In step ①, the oxygen pressure of the high-oxygen-pressure atmosphere is 20 MPa.

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

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

[0068] Example 4

[0069] A method for preparing Sm using MOD 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 the MOD method. 0.75 Sr 0.25 NiO3 perovskite nickel oxide thin films are produced 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. A thin film is then formed on a single-crystal substrate through coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on the 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 MOD 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 annealing temperature is 550 °C.

[0077] In step ①, the oxygen pressure of the high-oxygen-pressure atmosphere is 50 MPa.

[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 (Nd) using MOD technology 0.8 Pr 0.2 ) 0.75 Sr 0.25 A method for producing an infinite-layer nickel-based superconducting thin film of NiO2, characterized by comprising the following steps:

[0082] ①Deposition: Nd2+ crystals are grown on single-crystal substrates using the MOD method. 0.8 Pr 0.2 ) 0.75 Sr 0.25 NiO3 perovskite nickel oxide thin films are produced by mixing Ni, Nd, Pr, and Sr metal-organic sources in a designed ratio (1:0.60:0.15:0.25) in the organic solvent diethylene glycol, heating to 80 °C and stirring until completely dissolved, then cooling to room temperature to obtain a mixed metal-organic source solution. A thin film is formed on a single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components, ultimately resulting in the thermal deposition and growth of a 113-phase perovskite nickel oxide thin film on the 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 MOD process is a metal coordination compound of Ni, Sr, Pr and Nd, with the chemical formulas Ni(tmhd)2, Sr(tmhd)3(CH3O(CH2CH2O)4CH3), Pr(tmhd)3(tmphen), and Nd(tmhd)3(bipy), respectively.

[0085] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of (Nd... 0.8 Pr 0.2 ) 0.75 Sr 0.25 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 annealing temperature is 700 °C.

[0089] In step ①, the oxygen pressure of the high-oxygen-pressure atmosphere is 1 MPa.

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

[0091] In step ②, the annealing time is 5 hours, and after annealing, the material is cooled directly to room temperature within 60 minutes.

[0092] Example 6

[0093] A method for preparing (Nd) using MOD technology 0.8 Eu 0.2 ) 0.85 Sr 0.15 A method for producing an infinite-layer nickel-based high-temperature superconducting NiO2 thin film, characterized by comprising the following steps:

[0094] ① Deposition: Perovskite nickel oxide thin films were grown on single-crystal substrates using the MOD method. Specifically, metal-organic sources of Ni, Nd, Eu, and Sr were mixed in a designed ratio (1:0.68:0.17:0.15) in the organic solvent diethylene glycol, heated to 100 °C, and stirred until completely dissolved. The mixture was then cooled to room temperature to obtain a mixed metal-organic source solution. A thin film was formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film was thermally deposited on the 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 MOD process is a metal coordination compound of Ni, Sr, Nd and La, with the chemical formulas Ni(tmhd)2, Sr(tmhd)3(tmphen), Nd(tmhd)3(bipy), and La(hfac)3(CH3OCH2CH2OCH3), respectively.

[0097] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of (Nd... 0.8 Eu 0.2 ) 0.85 Sr 0.15 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 annealing temperature is 800 ℃.

[0101] In step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 50 MPa.

[0102] In step ②, the annealing temperature range is 350 °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 (Sm) using MOD technology 0.6 Nd 0.4 ) 0.75 Sr 0.25 A method for producing an infinite-layer nickel-based high-temperature superconducting NiO2 thin film, characterized by comprising the following steps:

[0106] ① Deposition: Perovskite nickel oxide thin films were grown on single-crystal substrates using the MOD method. Specifically, metal-organic sources of Ni, Sm, Nd, and Sr were mixed in a designed ratio (1:0.45:0.3:0.25) in the organic solvent toluene, heated to 80°C, and stirred until completely dissolved. The mixture was then cooled to room temperature to obtain a mixed metal-organic source solution. A thin film was formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film was thermally deposited on the 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 MOD process is a metal coordination compound of Ni, Sr, Nd and Sm, with the chemical formulas Ni(tmhd)2(CH3O(CH2CH2O)2CH3), Sr(tmhd)3(neo), Nd(tmhd)3(CH3O(CH2CH2O)2CH3), and Sm(hfac)3, respectively.

[0109] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of (Sm 0.6 Nd 0.4 ) 0.75 Sr 0.25 NiO3.

[0110] In step ①, the thickness of the perovskite nickel oxide film is controlled at 10 nm.

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

[0112] In step ①, the annealing temperature is 550 °C.

[0113] In step ①, the oxygen pressure of the high-oxygen-pressure atmosphere is 50 MPa.

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

[0115] In step ②, the annealing time is 3 hours, and after annealing, it is directly cooled to room temperature within 30 minutes.

[0116] Example 8

[0117] A method for preparing (Gd) using MOD technology 0.5 Nd 0.5 ) 0.8 Sr 0.2 A method for producing an infinite-layer nickel-based high-temperature superconducting NiO2 thin film, characterized by comprising the following steps:

[0118] ① Deposition: Perovskite nickel oxide thin films are grown on single-crystal substrates using the MOD method. Specifically, metal-organic sources of Ni, Gd, Nd, and Sr are mixed in a designed ratio (1:0.4:0.4:0.2) in the organic solvent toluene, heated to 80°C, and stirred until completely dissolved. The mixture is then cooled to room temperature to obtain a mixed metal-organic source solution. A thin film is formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film is thermally deposited on the single-crystal substrate.

[0119] 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 high-temperature superconducting thin film with 112 phases.

[0120] In step ①, the metal-organic source used in the MOD process is a metal coordination compound of Ni, Sr, Nd and Gd, with the chemical formulas Ni(tmhd)2(phen), Sr(tmhd)3(CH3O(CH2CH2O)4CH3), Nd(tmhd)3(CH3O(CH2CH2O)2CH3), and Gd(hfac)3, respectively.

[0121] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of (Gd... 0.5 Nd 0.5 ) 0.8 Sr 0.2 NiO3.

[0122] In step ①, the thickness of the perovskite nickel oxide film is controlled at 15 nm.

[0123] In step ①, the single crystal substrate is NdGaO3(110).

[0124] In step ①, the annealing temperature is 600 ℃.

[0125] In step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 100 MPa.

[0126] In step ②, the annealing temperature range is 350 °C.

[0127] In step ②, the annealing time is 3 hours, and after annealing, it is directly cooled to room temperature within 50 minutes.

[0128] Example 9

[0129] A method for preparing (Dy) using MOD technology 0.2 Nd 0.8 ) 0.8 Sr 0.2 A method for producing an infinite-layer nickel-based high-temperature superconducting NiO2 thin film, characterized by comprising the following steps:

[0130] ① Deposition: Perovskite nickel oxide thin films were grown on single-crystal substrates using the MOD method. Specifically, metal-organic sources of Ni, Dy, Nd, and Sr were mixed in a designed ratio (1:0.16:0.64:0.2) in the organic solvent toluene, heated to 100 °C, and stirred until completely dissolved. The mixture was then cooled to room temperature to obtain a mixed metal-organic source solution. A thin film was formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film was thermally deposited on the single-crystal substrate.

[0131] 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 high-temperature superconducting thin film with 112 phases.

[0132] In step ①, the metal-organic source used in the MOD process is a metal coordination compound of Ni, Sr, Nd and Dy, with the chemical formulas Ni(tmhd)2(phen), Sr(tmhd)3, Nd(tmhd)3(CH3O(CH2CH2O)2CH3), and Dy(tmhd)3(batho), respectively.

[0133] In step ①, the perovskite nickel oxide thin film material is a 113 phase with a composition of (Dy 0.2 Nd 0.8 ) 0.8 Sr 0.2 NiO3.

[0134] In step ①, the thickness of the perovskite nickel oxide film is controlled at 10 nm.

[0135] In step ①, the single crystal substrate is NdGaO3(110).

[0136] In step ①, the annealing temperature is 500 °C.

[0137] In step ①, the oxygen pressure of the high-oxygen-pressure atmosphere is 100 MPa.

[0138] In step ②, the annealing temperature range is 300 °C.

[0139] In step ②, the annealing time is 6 hours, and after annealing, it is directly cooled to room temperature within 50 minutes.

Claims

1. A method for preparing infinite-layer nickel-based superconducting thin films using metal-organic deposition (MOD) 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 includes the following steps: ① Deposition: Perovskite nickel oxide thin films are grown on single-crystal substrates using the MOD method. 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. A thin film is formed on the single-crystal substrate by coating, followed by drying and high-temperature, high-oxygen-pressure annealing to decompose the organic components. Finally, a 113-phase perovskite nickel oxide thin film is thermally deposited and grown on the single-crystal substrate. 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.

2. The method for preparing an infinite-layer nickel-based superconducting thin film using MOD technology as described in claim 1, wherein the metal-organic source used in the MOD 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 MOD 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 MOD 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 MOD 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 MOD 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 5–20 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 annealing temperature range is 500-900 °C.

11. The preparation method according to claim 1, wherein in step ①, the oxygen pressure range of the high oxygen pressure atmosphere is 0.1-100 MPa.

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 1-6 hours, and after annealing, the material is directly cooled to room temperature within 30-60 minutes.

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