A (Sm 2-a Y a )Ba4CuBiO 10 Nanopowder and method for improving the properties of single-domain SmBCO superconducting bulk materials using the same

Abstract

The application provides a kind of (Sm 2‑a Y a )Ba4CuBiO 10 Nanopowder and method for improving the performance of single-domain SmBCO superconducting bulk material by using the same, the value range of a of the nanoparticle is 0≤a≤2;The (Sm 2‑a Y a )Ba4CuBiO 10 Nanoparticle preparation method, comprising the following steps: 1), Sm2O3, Y2O3, Ba2CO3, CuO, Bi2O3 are mixed in different molar ratios of each component;2), the mixed powder in step 1) is ball milled for 2h-3h;3), the mixed powder is ground for 0.5-1h;4), the ground powder in step 3) is sintered for 24h, and the sintered powder is ball milled for 2h;5), step 4) is repeated at least 3 times to obtain (Sm 2‑a Y a )Ba4CuBiO 10 Powder;By replacing Sm element in REM2411 phase with Y element, a kind of (Sm 2‑a Y a )Ba4CuBiO 10 (0≤a≤2) Nanopowder is provided, and the performance of SmBCO superconducting bulk material is improved by doping the nanopowder in SmBCO superconducting bulk material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature REBCO superconducting bulk materials, and particularly relates to a (Sm 2-a Y a )Ba4CuBiO 10 nanoparticle and a preparation method thereof, a method for doping, improving and enhancing the performance of SmBCO superconducting bulk materials through (Sm 2-a Y a )Ba4CuBiO 10 nanoparticles. BACKGROUND

[0002] For many years, the research on superconducting materials has attracted more and more attention. In 1987, YBCO superconductor was discovered, and its critical temperature is higher than the liquid nitrogen temperature. Subsequently, a series of high-temperature superconductors with a transition temperature of about 90K were obtained by replacing Y in YBCO superconductor with rare earth elements such as Nd, Sm, Gd and Eu, and this kind of superconductor is called REBCO high-temperature superconductor. Among the REBCO series of high-temperature superconducting bulk materials, SmBCO superconducting material not only has a higher superconducting transition temperature than YBCO and GdBCO, but also has a higher critical current density in a medium-strength magnetic field, and is widely used in superconducting magnetic suspension, superconducting motor and superconducting flywheel energy storage, etc. Therefore, it has attracted more attention. However, the SmBCO superconducting bulk material prepared by the top seed crystal infiltration growth method (TSIG) still has the disadvantage of weak magnetic flux pinning ability. Scientists have taken many methods to overcome this problem, such as refining RE2BaCuO5 (RE211) particles to increase RE211 / RE123 interface defects; particle bombardment and high-energy particle radiation to produce tiny self-defects; and doping small second-phase particles can also produce tiny defects. By introducing RE2Ba4CuMO y (REM2411, M = U, Mo, Zr, Bi, Nb, W,...) nanoparticles through chemical doping, the nanoparticles cannot react with RE123 phase, and can effectively improve the sample magnetic suspension force, trapped magnetic field, etc. However, so far, there is no work on the improvement of this kind of non-superconducting REM2411 nanoparticles, which hinders the development of REBCO superconducting bulk materials. Therefore, it is of great significance to develop new type of nanoparticle magnetic flux pinning source powder capable of improving the superconducting performance of REBCO bulk materials on the basis of REM2411 nanoparticle powder.

[0003] REBCO bulk superconductor has been paid much attention due to its excellent superconducting properties, such as superior magnetic flux pinning ability, large magnetic levitation force and good self-stabilized magnetic levitation characteristics. However, these superconducting properties will gradually decay over time under the influence of the environment. The increase of magnetic flux pinning center can improve this problem. At present, the artificial magnetic flux pinning center is known to have many applications, but it will be limited due to two reasons, one is relatively expensive, and the other is that it may have a negative impact on the superconducting properties of the bulk superconductor. The REM2411 particle has small and stable particle size, and will not chemically react with the Ba-Cu-O liquid phase, and has good chemical stability. Without complex chemical preparation method or long time ball milling process, the nano to submicron REM2411 particles can be effectively introduced into the REBCO superconductor to form effective magnetic flux pinning center in the REBCO bulk superconductor. However, how to optimize the RE2Ba4CuMO y composition, research and development of new nanomaterials as effective magnetic flux pinning center? How to improve the critical current density, magnetic levitation force, trapped magnetic field and other superconducting properties of REBCO bulk superconductor by doping this new type of nanoparticles? Since the discovery of REM2411 phase nanopowder, these problems have been stagnant and no new progress has been made, which has greatly limited the development of REBCO bulk superconductor. Therefore, by replacing Sm element in REM2411 phase with Y element, we invented a kind of (Sm 2-a Y a )Ba4CuBiO 10 (0≤a≤2) nanopowder, and studied the effect of its doping on the performance of SmBCO bulk superconductor, which is of great significance to further improve the performance of SmBCO bulk superconductor. SUMMARY

[0004] The purpose of the present application is to improve the performance of SmBCO bulk superconductor by replacing Sm element in REM2411 phase with Y element and doping it.

[0005] To achieve the above purpose, the present application provides a kind of (Sm 2-a Y a )Ba4CuBiO 10 nanoparticle, wherein 0≤a≤2, further, the preparation method of the (Sm 2-a Y a )Ba4CuBiO 10 nanoparticle comprises the following steps:

[0006] 1) Sm2O3, Y2O3, Ba2CO3, CuO and Bi2O3 with a purity of 99.0% are mixed according to the value of a and the different molar ratio of each component.

[0007] 2) Put the mixed powder in step 1) into a marver jar, and ball mill in a planetary ball mill for 2h-3h;

[0008] 3) Put the mixed powder in the marver jar into a mortar for grinding; grind for 0.5-1h until no large particles appear;

[0009] 4) Put the ground powder in step 3) into a high-temperature furnace, and sinter at a temperature T (T=930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃) for 24h; then ball mill the sintered powder for 2h;

[0010] 5) Repeat step 4) for at least 3 times to obtain (Sm 2-a Y a )Ba4CuBiO 10 powder.

[0011] The preparation method of the (Sm 2-a Y a )Ba4CuBiO 10 nanoparticles is as follows: 1 mole-0 mole of Sm2O3, 0 mole-1 mole of Y2O3, 4 moles of BaCO3, 1 mole of CuO, and 0.5 moles of Bi2O3; the chemical formula of the nanopowder is (Sm 2-a Y a )Ba4CuBiO 10 , wherein the value range of a is 0≤a≤2.

[0012] 6) Further, a method for doping (Sm 2-a Y a )Ba4CuBiO 10 nanoparticles to improve the performance of SmBCO superconducting bulk material, comprising the following steps:

[0013] 1) Preparation of the (Sm 2-a Y a )Ba4CuBiO 10 nanoparticles;

[0014] 2) Preparation of seed crystal

[0015] 2.1) Preparation of Nd123 powder: uniformly mix Nd2O3, BaCO3, and CuO powders in a molar ratio of 1:4:6, and generate NdBa2Cu3O 7-δ (Nd123) powder by solid-state reaction method at 910℃ through three times of sintering and four times of ball milling;

[0016] 2.2) Preparation of Nd2i i powder: Nd2O3, BaCO3 and CuO powders are mixed uniformly in a molar ratio of 1:1:1, and then sintered three times at 920°C by solid-state reaction and ball-milled four times to obtain Nd2BaCuO5 (Nd2i i) powder;

[0017] 2.3) Finally, the Nd123 powder and the Nd2i i powder are mixed in a mass ratio of 3:1, and 8wt% MgO powder is added and mixed uniformly. The mixed powder is weighed and pressed into a NdBCO precursor block with equal diameter. The NdBCO block is grown in a crystal growth furnace to obtain a NdBCO bulk material. A small piece of naturally cleaved NdBCO is used as a NdBCO seed crystal;

[0018] 3) Preparation of BaCuO2 powder

[0019] BaCO3 and CuO are mixed uniformly in a molar ratio of 1:1, and then sintered at least three times at 897°C, 900°C and 903°C by solid-state reaction and ball-milled at least four times to obtain BaCuO2 powder;

[0020] 4) Preparation of solid-liquid phase

[0021] 4.1) Preparation of solid-phase precursor block

[0022] The solid-phase source powder is composed of the following components: (100-x) (Sm2O3+1.2BaCuO2) + x (Sm 2-a Y a ) Ba4CuBiO 10 (x = 0, 1, 3, 5, 7, 9wt%) + 1wt% CeO2 powder is mixed uniformly by a ball mill and a mortar and used as a solid-phase source. The solid-phase precursor block is prepared by pressing into a cylindrical blank.

[0023] 4.2) Preparation of liquid-phase precursor block

[0024] The liquid-phase source powder is composed of Y2O3, BaCuO2 and CuO2 powders mixed uniformly in a molar ratio of 1:10:6. The mixed powder is used as a liquid-phase source and pressed into a cylindrical blank to complete the preparation of the liquid-phase precursor block.

[0025] 5) Assembly of solid-liquid phase

[0026] 5.1) Prepare several MgO single crystal blocks and Al2O3 spacers;

[0027] 5.2), the liquid precursor block, solid precursor block is placed in accordance with the axial symmetry: first, on the Al2O3 pad placed an appropriate number of MgO single crystal; second, the upper surface of the MgO single crystal from bottom to top in turn placed liquid precursor block, solid precursor block; third, the prepared NdBCO seed crystal is placed in the upper surface of the solid precursor block center position, and let NdBCO seed crystal ab surface and the surface of the solid precursor block parallel;

[0028] 6), the growth and oxygenation of the sample

[0029] 6.1), the heat treatment process: the solid-liquid phase assembly in step 5) is put into a high temperature furnace, first heated to 850 DEG C at a rate of 120 DEG C / h, 10 h after heat preservation, then rapidly heated to 1070 DEG C at a rate of 150 DEG C / h, 1.5 h after heat preservation, cooled to 1060 DEG C at a rate of 60 DEG C / h, then slow cooling growth, cooled to 1044 DEG C at a rate of 0.5 DEG C / h, finally cooled to room temperature with the furnace;

[0030] 6.2), oxygenation treatment: the grown single domain SmBCO block is put into an oxygenation furnace, then the single domain SmBCO block is passed through 200 ml / min flow of oxygen, heated to 290 DEG C, then slow cooling to 270 DEG C, 200 h after heat preservation, the block is cooled to room temperature at a rate of 90 DEG C / h, finally get SmBCO superconducting block by tetragonal phase without superconductivity into orthorhombic phase with superconductivity.

[0031] Further, the method for improving the performance of SmBCO superconducting block by (Sm 2-a Y a )Ba4CuBiO 10 Nanoparticle doping, improving the performance of SmBCO superconducting block method, the support block is pressed into a cylindrical billet using 5g Y2O3 powder.

[0032] Further, in step 5.2), second, the upper surface of the MgO single crystal from bottom to top in turn placed the support block, liquid precursor block and solid precursor block.

[0033] Further, in step 4.1), 15g, the diameter of the cylindrical billet is 20mm;

[0034] Further, in step 4.2), 27g, the diameter of the cylindrical billet is 30mm.

[0035] Further, in step 4.1), the Sm2Ba4CuBiO 10 Doping amount between 0 2-a Y a )Ba4CuBiO10 doping amount is between 0 < x ≤ 5wt%, wherein the value of a is 0 < a ≤ 1, the (Sm 2-a Y a )Ba4CuBiO 10 doping amount is between 0 < x ≤ 3wt%, wherein 1 < a < 2. The Y2Ba4CuBiO 10 doping amount is between 0 < x ≤ 1wt%.

[0036] The advantage of the present application is that by replacing the Sm element in REM2411 phase with Y element, a (Sm 2- a Y a )Ba4CuBiO 10 (0 ≤ a ≤ 2) nanopowder is provided, and by doping the nanopowder in SmBCO superconducting bulk material, the performance of the SmBCO superconducting bulk material is improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is the Sm2Ba4CuBiO 10 powder XRD ray diffraction spectrum after sintering at different temperatures.

[0038] Figure 2 is the SEM image of Sm2Ba4CuBiO 10 particles at different sintering temperatures.

[0039] Figure 3 is the assembly diagram of SmBCO superconducting bulk material in RE+011TSIG method.

[0040] Figure 4 is the schematic diagram of heat treatment process of SmBCO bulk material.

[0041] Figure 5 is the macroscopic morphology diagram of SmBCO bulk material doped with 7wt% Sm2Ba4CuBiO 10 powder.

[0042] Figure 6 is the magnetic levitation force curve diagram of SmBCO sample doped with 7wt% Sm2Ba4CuBiO 10 powder.

[0043] Figure 7 is the surface magnetic field distribution of SmBCO bulk material doped with 7wt% Sm2Ba4CuBiO 10 powder.

[0044] Figure 8 is the microstructure diagram of SmBCO sample doped with 7wt% Sm2Ba4CuBiO 10 powder.

[0045] Figure 9 SmYBa4CuBiO 1.5 Y 0.5 SmYBa4CuBiO 10 XRD pattern of the powder.

[0046] Figure 10 SmYBa4CuBiO 1.5 Y 0.5 SmYBa4CuBiO 10 SEM image of the particles.

[0047] Figure 11 SmYBa4CuBiO 1.5 Y 0.5 SmYBa4CuBiO 10 Macroscopic morphology of the SmBCO bulk from the powder.

[0048] Figure 12 SmYBa4CuBiO 1.5 Y 0.5 SmYBa4CuBiO 10 Magnetic levitation force curve of the SmBCO sample from the powder.

[0049] Figure 13 SmYBa4CuBiO 1.5 Y 0.5 SmYBa4CuBiO 10 Trapped magnetic field distribution of the SmBCO bulk.

[0050] Figure 14 SmYBa4CuBiO 10 XRD pattern of the powder.

[0051] Figure 15 SmYBa4CuBiO 10 SEM image of the particles.

[0052] Figure 16 SmYBa4CuBiO 10 Macroscopic morphology of the SmBCO bulk from the powder.

[0053] Figure 17 SmYBa4CuBiO 10 Magnetic levitation force curve of the SmBCO sample.

[0054] Figure 18 SmYBa4CuBiO 10 Trapped magnetic field distribution of the SmBCO bulk.

[0055] Figure 19For doped SmYBa4CuBiO 10 Microstructure diagram of SmBCO powder sample.

[0056] Figure 20 Sm after sintering at different temperatures 0.5 Y 1.5 Ba4CuBiO 10 XRD pattern of powder.

[0057] Figure 21 Sm at different sintering temperatures 0.5 Y 1.5 Ba4CuBiO 10 SEM image of the particles.

[0058] Figure 22 Different Sm 0.5 Y 1.5 Ba4CuBiO 10 Macroscopic morphology of the upper surface of a SmBCO doped superconducting sample.

[0059] Figure 23 Different Sm 0.5 Y 1.5 Ba4CuBiO 10 Magnetic levitation force curve of SmBCO doped sample.

[0060] Figure 24 Different Sm 0.5 Y 1.5 Ba4CuBiO 10 Distribution of the magnetic field trapped in bulk SmBCO material with high doping level.

[0061] Figure 25 Y2Ba4CuBiO sintered at different temperatures 10 XRD pattern of powder.

[0062] Figure 26 Y2Ba4CuBiO at different sintering temperatures 10 SEM image of the particles.

[0063] Figure 27 1wt% Y2Ba4CuBiO 10 Macroscopic morphology of SmBCO powder in bulk form.

[0064] Figure 28 1wt% Y2Ba4CuBiO 10 Magnetic levitation force curve of SmBCO powder sample.

[0065] Figure 29 1wt% Y2Ba4CuBiO 10SmBCO bulk trap magnetic field distribution map. DETAILED DESCRIPTION

[0066] Example 1

[0067] 1) (Sm 2-a Y a )Ba4CuBiO 10 The ratio of the powder and the weighing.

[0068] The commercially purchased Sm2O3, Ba2CO3, CuO, Bi2O3 with a purity of 99.0% were mixed according to the atomic molar ratio Sm:Ba:Cu:Bi = 2:4:1:1 to prepare 30g of powder. Sm2O3 powder 7.204g, BaCO3 powder 16.303g, CuO powder 1.681g, Bi2O3 powder 4.812g were weighed into a agate jar.

[0069] 2) The powder in the agate jar was placed in a planetary ball mill and ball milled for 2h.

[0070] 3) After taking out the mixed powder, put it in a mortar and grind it to ensure uniform mixing, grind for 0.5-1h.

[0071] 4) Put the mixed powder into a high temperature furnace and sinter at temperature T (T = 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃) for 24h, and ball mill the sintered powder for 2h.

[0072] 5) Repeat step 4 for 3 times to get higher purity Sm2Ba4CuBiO 10 powder.

[0073] 6) Analyze the powder phase and microstructure morphology by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and select the smallest particle size and highest purity Sm2Ba4CuBiO 2-a Y a )Ba4CuBiO 10 powder.

[0074] Figure 1 The XRD pattern of the precursor powder Sm2Ba4CuBiO 10 sintered at 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃.

[0075] Figure 2 The SEM pattern of the precursor powder Sm2Ba4CuBiO 10 sintered at 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃. Figure 2Middle: (a) part temperature is 930℃; (b) part temperature is 950℃; (c) part temperature is 970℃; (d) part temperature is 990℃; (e) part temperature is 1010℃; (f) part temperature is 1050℃.

[0076] 7) (100-x) (Sm2O3+1.2BaCuO2)+xSm2Ba4CuBiO 10 (x=0, 1, 3, 5, 7, 9wt%) solid phase powder is mixed uniformly and pressed into a solid phase precursor block, (Y2O3+10BaCuO2+6CuO) mixed powder is pressed into a liquid phase source block, after the precursor block (i.e. solid phase precursor block and liquid phase precursor block) is pressed, as shown in Figure 3 The assembly diagram of SmBCO superconducting bulk material in the RE+011TSIG method is shown, first, the uniform MgO single crystal is spread on the Al2O3 plate, then the solid phase precursor block, the transport layer, the liquid phase precursor block and the spacer are placed in order from top to bottom along the central axis, finally the NdBCO seed crystal is placed on the center of the upper surface of the solid phase precursor block, and the ab plane of the bright NdBCO seed crystal is parallel to the solid phase surface. It should be noted that the transport layer is Y2O3, which is used to avoid direct contact between the solid phase block and the liquid phase block at high temperature, and is easy to separate after the sample is completed.

[0077] 8) Put the assembled SmBCO superconducting bulk material into a high-temperature crystal growth furnace and grow according to the debugged program. The heat treatment program is shown in Figure 4 .

[0078] When the doping amount x of Sm2Ba4CuBiO 10 powder is less than or equal to 7wt%, the sample can be grown into a complete single-domain SmBCO bulk material, Figure 5 doped with 7wt% Sm2Ba4CuBiO 10 powder.

[0079] 9) The grown SmBCO superconducting bulk material sample is subjected to oxygen permeation treatment: the single-domain SmBCO bulk material is put into a high-temperature oxygen permeation furnace designed by the laboratory, then the sample is given oxygen with a flow rate of 200ml / min, heated to 290℃, and kept for a period of time. Then slowly cool to 270℃, keep for 200h, and finally cool the sample to room temperature at a rate of 90℃ / h, so that the sample is converted from tetragonal phase to orthorhombic phase with superconducting property, to obtain SmBCO superconducting phase.

[0080] 10) The magnetic levitation force of the SmBCO sample doped with 7wt% Sm2Ba4CuBiO 10 nanoparticles is tested by using the three-dimensional magnetic field measurement system designed by the laboratory. Figure 6The magnetic levitation force-distance curve between permanent magnet (NdFeB, Φ = 20 mm, B = 0.5 ± 0.01 T) and sample in the zero field cooling (ZFC) state at liquid nitrogen temperature (77 K) is shown.

[0081] For the measurement of the trapped field, the single domain SmBCO superconductor was cooled to 77 K under a 0.5 ± 0.01 T magnetic field (NdFeB, Φ = 20 mm) perpendicular to the surface and held for 5 minutes, then the data was collected at 0.5 mm above the surface of the SmBCO superconductor by a Hall probe following a set path, Figure 7 The Sm2Ba4CuBiO 10 The 3D trapped field mapping of the SmBCO sample of the powder.

[0082] 11) The grown SmBCO superconducting bulk was cut and the internal microstructure of the sample was observed, such as Figure 8 The Sm2Ba4CuBiO 10 The microstructure of the SmBCO sample of the powder.

[0083] Example 2:

[0084] 1) (Sm 2-a Y a )Ba4CuBiO 10 The powder was prepared by mixing Sm2O3, Y2O3, Ba2CO3, CuO and Bi2O3 with atomic molar ratio Sm:Y:Ba:Cu:Bi = 1.5:0.5:4:1:1, and the powder was weighed.

[0085] The Sm2O3, Y2O3, Ba2CO3, CuO and Bi2O3 with purity of 99.0% were mixed according to the atomic molar ratio Sm:Y:Ba:Cu:Bi = 1.5:0.5:4:1:1, and 30 g of powder was prepared. The Sm2O3 powder 5.520 g, Y2O3 powder 1.191 g, BaCO3 powder 16.656 g, CuO powder 1.717 g and Bi2O3 powder 4.916 g were weighed and put into a garnet pot.

[0086] 2) The powder in the garnet pot was put into a planetary ball mill and ball milled for 2 h.

[0087] 3) The mixed powder was taken out and ground in a mortar.

[0088] 4) The uniformly mixed powder was put into a high-temperature furnace and sintered at a temperature T (T = 930 ℃, 950 ℃, 970 ℃, 990 ℃, 1010 ℃, 1050 ℃) for 24 h, and the sintered powder was ball milled for 2 h.

[0089] 5) Step 4 was repeated 3 times to obtain higher purity Sm 1.5 Y 0.5 Ba4CuBiO 10Powder.

[0090] 6) The phase composition and microstructure of the powder were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and Sm was selected with the smallest particle size and highest purity. 1.5 Y 0.5 Ba4CuBiO 10 Powder. Figure 9 The image shows Sm 1.5 Y 0.5 Ba4CuBiO 10 XRD patterns of the precursor powder after sintering at six temperature points: 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃.

[0091] Figure 10 The image shows Sm 1.5 Y 0.5 Ba4CuBiO 10 SEM images of the precursor powder after sintering at six temperature points: 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃. Figure 10 In the middle: (a) the temperature is 930℃; (b) the temperature is 950℃; (c) the temperature is 970℃; (d) the temperature is 990℃; (e) the temperature is 1010℃; (f) the temperature is 1050℃.

[0092] 7) (100-x)(Sm2O3+1.2BaCuO2)+xSm 1.5 Y 0.5 Ba4CuBiO 10 (x=0, 1, 3, 5, 7, 9wt%) solid powder is uniformly mixed and pressed into solid phase precursor blocks. (Y2O3+10BaCuO2+6CuO) mixed powder is pressed into liquid phase precursor blocks. After the precursor blocks (solid phase precursor blocks and liquid phase precursor blocks) are pressed, MgO single crystals of equal height are uniformly spread on Al2O3 plates. Then, the solid phase precursor blocks, transport layer, liquid phase precursor blocks and spacers are placed in layers from top to bottom along the central axis. Finally, NdBCO seed crystals are placed in the center of the upper surface of the solid phase, and the ab plane of the bright NdBCO seed crystals is placed parallel to the surface of the solid phase.

[0093] 8) Place the assembled SmBCO block into a high-temperature crystal growth furnace and grow it according to the pre-programmed procedure. The heat treatment procedure is as follows: Figure 4 As shown. When Sm 1.5 Y 0.5 Ba4CuBiO 10 When the powder doping amount x ≤ 5wt%, the samples can all grow into complete single-domain bulk materials. Figure 11 The image shown is of a 5wt% Sm doped sample.1.5 Y 0.5 Ba4CuBiO 10 Macroscopic morphology of SmBCO bulk from powder.

[0094] 9) The grown single domain SmBCO bulk sample was treated by oxygen diffusion. The single domain SmBCO bulk was put into a high temperature oxygen diffusion furnace designed by the laboratory, and then the sample was supplied with oxygen at a flow rate of 200 ml / min, heated to 290°C, and kept for a period of time. Then slowly cooled to 270°C, and kept for 200h, and finally cooled to room temperature at a rate of 90°C / h, so that the sample was converted from tetragonal phase to orthorhombic phase with superconducting properties, to obtain SmBCO superconducting phase.

[0095] 10) The 5wt% Sm-doped SmBCO bulk sample was tested by a three-dimensional magnetic field measurement system designed by the laboratory. 1.5 Y 0.5 Ba4CuBiO 10 Magnetic levitation force of SmBCO sample from nanoparticle. Figure 12 The magnetic levitation force-distance curve between permanent magnet (NdFeB, Φ = 20mm, B = 0.5±0.01T) and sample is shown in the zero field cooling (ZFC) state at liquid nitrogen temperature (77K).

[0096] For the measurement of the trapped magnetic field, the single domain SmBCO superconductor was cooled to 77K under a 0.5±0.01T magnetic field (NdFeB, Φ = 20mm) perpendicular to the surface for 5 minutes, and then the data was collected at a distance of 0.5mm above the surface of the SmBCO superconductor by a Hall probe following a set path, Figure 13 The 5wt% Sm-doped SmBCO bulk sample is shown. 1.5 Y 0.5 Ba4CuBiO 10 3D trapped field mapping of SmBCO sample from powder.

[0097] Example 3:

[0098] 1) (Sm 2-a Y a )Ba4CuBiO 10 Powder preparation and weighing.

[0099] Sm2O3, Y2O3, Ba2CO3, CuO, Bi2O3 with a purity of 99.0% purchased commercially were mixed according to the atomic molar ratio Sm:Y:Ba:Cu:Bi = 1:1:4:1:1 to prepare 30g of powder. Sm2O3 powder 3.761g, Y2O3 powder 2.435g, BaCO3 powder 17.024g, CuO powder 1.755g, and Bi2O3 powder 5.025g were weighed into a agate pot.

[0100] 2) Put the powder in the agate jar into the planetary ball mill and ball mill for 2h.

[0101] 3) Take out the mixed powder and grind it in a mortar.

[0102] 4) Put the uniformly mixed powder into a high-temperature furnace and sinter it at a temperature T (T = 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃) for 24h, and ball mill the sintered powder for 2h.

[0103] 5) Repeat step 4 for 3 times to obtain SmYBa4CuBiO 10 powder with higher purity.

[0104] 6) Analyze the phase and microstructure morphology of the powder by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and select the SmYBa4CuBiO 10 powder with the smallest particle size and the highest purity. As shown below: Figure 14 SmYBa4CuBiO 10 precursor powder sintered at six temperature points of 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃.

[0105] Figure 14 The XRD spectra of SmYBa4CuBiO 10 powder sintered at different temperatures are as shown below: Figure 15 SmYBa4CuBiO 10 precursor powder sintered at six temperature points of 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃. Figure 14 (a) The temperature of part (a) is 930℃; (b) The temperature of part (b) is 950℃; (c) The temperature of part (c) is 970℃; (d) The temperature of part (d) is 990℃; (e) The temperature of part (e) is 1010℃; (f) The temperature of part (f) is 1050℃.

[0106] 7) (100-x)(Sm2O3+1.2BaCuO2)+xSmYBa4CuBiO 10(x = 0, 1, 3, 5, 7, 9 wt%) solid phase powder was mixed uniformly and pressed into a solid phase precursor block, (Y2O3+10BaCuO2+6CuO) mixed powder was pressed into a liquid phase precursor block, after the solid and liquid phase precursor blocks were pressed, first, the isometric MgO single crystal was uniformly spread on the Al2O3 plate, then the solid phase block, the transmission layer, the liquid phase block and the gasket were placed in layers along the central axis from top to bottom in turn, finally the NdBCO seed crystal was placed at the center of the upper surface of the solid phase, the color-bright NdBCO seed crystal ab plane was parallel to the surface of the solid phase, as shown in Figure 3 .

[0107] 8) The assembled SmBCO block was placed in a high-temperature crystal growth furnace, and the growth was carried out according to the debugged program. The heat treatment program is as shown in Figure 4 . When the SmYBa4CuBiO 10 powder doping amount x≤5wt%, the sample can be grown into a complete single-domain block, Figure 16 SmYBa4CuBiO 10 powder.

[0108] 9) The grown SmBCO block sample was subjected to oxygen permeation treatment. The single-domain SmBCO block was placed in a high-temperature oxygen permeation furnace designed by the laboratory, and then the sample was supplied with oxygen at a flow rate of 200ml / min, heated to 290℃, and kept for a period of time. Then slowly cool to 270℃, keep for 200h, and finally cool the sample to room temperature at a rate of 90℃ / h, so that the sample is converted from tetragonal phase to orthorhombic phase with superconducting property, to obtain SmBCO superconducting phase.

[0109] 10) The magnetic levitation force of the SmBCO sample doped with SmYBa4CuBiO 10 nanoparticles was tested by using a three-dimensional magnetic field measurement system designed by the laboratory. Figure 17 shows the magnetic levitation force-distance curve between the permanent magnet (NdFeB, Φ = 20mm, B = 0.5±0.01T) and the sample under the condition of zero field cooling (ZFC) at liquid nitrogen temperature (77K).

[0110] For the measurement of the trapped magnetic field, the single-domain SmBCO superconductor was cooled to 77K under a 0.5±0.01T magnetic field (NdFeB, Φ = 20mm) perpendicular to the surface, and kept for 5 minutes, then the data was collected at a distance of 0.5mm above the surface of the SmBCO superconductor by a Hall probe following the set path, Figure 18 shows the 3D trapped field mapping of the SmBCO sample doped with SmYBa4CuBiO 10 powder.

[0111] 11) Cut the grown SmBCO superconducting block and observe the internal microstructure of the sample. Figure 19 For doped SmYBa4CuBiO 10 Microstructure diagram of SmBCO powder sample.

[0112] Example 4:

[0113] 1)(Sm 2-a Y a Ba4CuBiO 10 The proportioning and weighing of powders.

[0114] Commercially purchased Sm2O3, Y2O3, Ba2CO3, CuO, and Bi2O3 with a purity of 99.0% were mixed in an atomic molar ratio of Sm:Y:Ba:Cu:Bi = 0.5:1.5:4:1:1 to prepare 30g of powder. 1.923g of Sm2O3 powder, 3.735g of Y2O3 powder, 17.409g of BaCO3 powder, 1.795g of CuO powder, and 5.138g of Bi2O3 powder were weighed and placed into an agate jar.

[0115] 2) Place the powder in the agate jar into a planetary ball mill and ball mill for 2 hours.

[0116] 3) After taking out the mixed powder, put it in a mortar and grind it.

[0117] 4) Place the uniformly mixed powder into a high-temperature furnace and sinter it at a temperature T (T=930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃) for 24 hours. Then, ball mill the sintered powder for 2 hours.

[0118] 5) Repeat step 4 three times to obtain Sm with higher purity. 0.5 Y 1.5 Ba4CuBiO 10 Powder.

[0119] 6) The phase composition and microstructure of the powder were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and Sm was selected with the smallest particle size and highest purity. 0.5 Y 1.5 Ba4CuBiO 10 Powder. For example... Figure 20 As shown: Sm 0.5 Y 1.5 Ba4CuBiO 10 XRD patterns of the precursor powder after sintering at six temperature points: 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃.

[0120] like Figure 21Sm 0.5 Y 1.5 Ba4CuBiO 10 SEM images of precursor powders sintered at 930℃, 950℃, 970℃, 990℃, 1010℃, 1050℃. Figure 21 (a) 930℃, (b) 950℃, (c) 970℃, (d) 990℃,

[0121] (e) 1010℃, (f) 1050℃.

[0122] 7) (100-x) (Sm2O3+1.2BaCuO2) + xSm 0.5 Y 1.5 Ba4CuBiO 10 (x = 0, 1, 3, 5, 7, 9wt%) solid phase precursor blocks were prepared by mixing the solid phase powders uniformly and pressing into blocks. The (Y2O3+10BaCuO2+6CuO) mixed powders were pressed into liquid phase precursor blocks. After the solid and liquid phase precursor blocks were prepared, the isometric MgO single crystal was spread uniformly on the Al2O3 plate. Then the solid phase block, the transport layer, the liquid phase block and the spacer were placed in order from top to bottom along the central axis. Finally, the color-bright NdBCO seed crystal was placed on the center of the upper surface of the solid phase block with the ab plane parallel to the surface of the solid phase block, as shown in Figure 3 .

[0123] 8) The assembled SmBCO block was placed in a high-temperature crystal growth furnace and grown according to the debugged program. The heat treatment program is shown in Figure 4 . When the Sm 0.5 Y 1.5 Ba4CuBiO 10 When the doping amount of the powder x≤3wt%, the sample can be grown into a complete single-domain block, Figure 22 Sm 0.5 Y 1.5 Ba4CuBiO 10 SmBCO block macroscopic morphology of the powder.

[0124] 9) The grown SmBCO block sample was subjected to oxygen permeation treatment. The single-domain SmBCO block was placed in a high-temperature oxygen permeation furnace designed by the laboratory, and then the sample was passed through 200ml / min flow of oxygen, heated to 290℃, and kept for a period of time. Then slowly cool to 270℃, and keep for 200h, and finally cool the sample to room temperature at a rate of 90℃ / h, so that the sample is converted from tetragonal phase to orthorhombic phase with superconducting property, to obtain SmBCO superconducting phase.

[0125] 10) The magnetic levitation force of the Sm-doped SmBCO samples was measured by using the 3D magnetic field measurement system designed by our lab. 0.5 Y 1.5 Ba4CuBiO 10 nanoparticles. Figure 23 The magnetic levitation force-distance curve between the permanent magnet (NdFeB, Φ = 20 mm, B = 0.5 ± 0.01 T) and the sample is shown in the zero-field-cooled (ZFC) state at liquid nitrogen temperature (77 K).

[0126] For the measurement of the trapped magnetic field, the single-domain SmBCO superconductor was cooled to 77 K under a 0.5 ± 0.01 T magnetic field (NdFeB, Φ = 20 mm) perpendicular to the surface and kept for 5 min, and then the data were collected at a distance of 0.5 mm above the surface of the SmBCO superconductor by a Hall probe following a set path, Figure 24 The 3D trapped field mapping of the Sm-doped SmBCO samples is shown. 0.5 Y 1.5 Ba4CuBiO 10 nanoparticles.

[0127] Example 5:

[0128] 1) The Sm-doped (SmY)Ba4CuBiO6powder was prepared by mixing Y2O3, Ba2CO3, CuO, Bi2O3 powders with an atomic molar ratio of Y:Ba:Cu:Bi = 2:4:1:1. 2-a Y a )Ba4CuBiO 10 powder.

[0129] The Y2O3, Ba2CO3, CuO, Bi2O3 powders with a purity of 99.0% were mixed according to the atomic molar ratio Y:Ba:Cu:Bi = 2:4:1:1, and 30 g of powder was prepared. Y2O3 powder 5.095 g, BaCO3 powder 17.811 g, CuO powder 1.836 g, and Bi2O3 powder 5.257 g were weighed into a garnet pot.

[0130] 2) The powder in the garnet pot was placed in a planetary ball mill and ball milled for 2 h.

[0131] 3) The mixed powder was taken out and ground in a mortar.

[0132] 4) The uniformly mixed powder was placed in a high-temperature furnace and sintered at a temperature T (T = 930 °C, 950 °C, 970 °C, 990 °C, 1010 °C, 1050 °C) for 24 h, and the sintered powder was ball milled for 2 h.

[0133] 5) Step 4 was repeated 3 times to obtain higher purity Y2Ba4CuBiO6powder. 10

[0134] ​6) The phase composition and microstructure of the powder were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and Y2Ba4CuBiO with the smallest particle size and highest purity was selected. 10 Powder, as follows Figure 25 As shown: Y2Ba4CuBiO 10 XRD patterns of the precursor powder after sintering at six temperature points: 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃. (See figure) Figure 26 As shown, Y2Ba4CuBiO 10 SEM images of the precursor powder after sintering at six temperature points: 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃. Figure 26 In the middle: (a) the temperature is 930℃; (b) the temperature is 950℃; (c) the temperature is 970℃; (d) the temperature is 990℃; (e) the temperature is 1010℃; (f) the temperature is 1050℃.

[0135] 7) The mixture (100-x)(Sm2O3+1.2BaCuO2)+xY2Ba4CuBiO 10 (x = 0, 1, 3, 5, 7, 9 wt%) solid powders were uniformly mixed and pressed into solid precursor blocks. A mixture of (Y₂O₃ + 10BaCuO₂ + 6CuO) powders was pressed into liquid precursor blocks. After the precursor blocks, i.e., the solid and liquid precursor blocks, were pressed, MgO single crystals of equal height were first uniformly spread on an Al₂O₃ plate. Then, the solid precursor block, transport layer, liquid precursor block, and spacer were placed sequentially from top to bottom along the central axis. Finally, an NdBCO seed crystal was placed at the center of the upper surface of the solid phase, with the ab plane of the bright NdBCO seed crystal parallel to the solid phase surface. Figure 3 As shown.

[0136] 8) Place the assembled SmBCO block into a high-temperature crystal growth furnace and grow it according to the pre-programmed procedure. The heat treatment procedure is as follows: Figure 4 As shown. When Y2Ba4CuBiO 10 When the powder doping amount x ≤ 1 wt%, the samples can all grow into complete single-domain bulk materials. Figure 27 1wt% Y2Ba4CuBiO 10 Macroscopic morphology of SmBCO powder in bulk form.

[0137] 9) The grown SmBCO bulk samples were treated by oxygen diffusion. The single domain SmBCO bulk was put into a high temperature oxygen diffusion furnace designed by our lab, then the sample was heated to 290°C and kept for a while, then the sample was slowly cooled to 270°C and kept for 200 hours, finally the sample was cooled to room temperature with a rate of 90°C / h, so that the sample was transformed from tetragonal phase to orthorhombic phase with superconductivity, and the SmBCO superconducting phase was obtained.

[0138] 10) The magnetic levitation force of the SmBCO samples doped with 1wt% Y2Ba4CuBiO 10 nanoparticles was measured by a three-dimensional magnetic force measurement system designed by our lab. Figure 28 The magnetic levitation force-distance curve between permanent magnet (NdFeB, Φ = 20mm, B = 0.5±0.01T) and sample in the zero field cooling (ZFC) state at liquid nitrogen temperature (77K) was shown.

[0139] For the measurement of trapped magnetic field, the single domain SmBCO superconductor was cooled to 77K under a 0.5±0.01T magnetic field (NdFeB, Φ = 20mm) perpendicular to the surface for 5 minutes, then the data was collected by a Hall probe at 0.5mm above the surface of the SmBCO superconductor along a set path, Figure 29 The 3D trapped field mapping of the SmBCO sample doped with 1wt% Y2Ba4CuBiO 10 nanoparticles was shown.

[0140] From the Sm2Ba4CuBiO 10 nanoparticles, the ratio of Sm element was continuously reduced until it became Y2Ba4CuBiO 10 When the SmBi2411 nanoparticles were doped into the SmBCO superconducting bulk, the best doping ratio could reach 7wt%, and with the reduction of Sm element, the best doping ratio was continuously reduced, and when the YBi2411 nanoparticles were doped into the SmBCO superconducting bulk, the best doping ratio only reached 1wt%.

Claims

1. A nanopowder, with the following molar ratio: 1 mol to 0 mol of Sm₂O₃, 0 mol to 1 mol of Y₂O₃, 4 mol of BaCO₃, 1 mol of CuO, and 0.5 mol of Bi₂O₃; the chemical formula of the nanopowder is (Sm₂O₃). 2-a Y a Ba4CuBiO 10 The range of values ​​for 'a' is 0. <a<2。 2. The method for preparing nanopowder according to claim 1, characterized in that, Includes the following steps: 1) Mix Sm2O3, Y2O3, Ba2CO3, CuO, and Bi2O3 with a purity of 99.0% according to the value of a, in different molar ratios for each component; 2) Place the mixed powder from step 1) into an agate jar and ball mill it in a planetary ball mill for 2 to 3 hours; 3) Place the mixed powder from the agate jar into a mortar and grind it for 0.5-1 hour; 4) Place the powder ground in step 3) into a high-temperature furnace and sinter at temperatures T = 930℃, 950℃, 970℃, 990℃, 1010℃, and 1050℃ for 24 hours. Then ball mill the sintered powder for 2 hours. 5) Repeat step 4) at least 3 times to obtain (Sm) 2-a Y a Ba4CuBiO 10 Powder.

3. A single-domain samarium barium copper oxide superconducting bulk material, characterized in that: In the superconducting bulk material (Sm 2-a Y a )Ba4CuBiO 10 The doping amount is between 0 < x ≤ 5 wt%, where 0 < a ≤ 1.

4. A single-domain samarium barium copper oxide superconducting bulk material, characterized in that: In the superconducting bulk material (Sm 2-a Y a )Ba4CuBiO 10 The doping amount is between 0 < x ≤ 3 wt%, where 1 < a < 2.

5. A method using (Sm) 2-a Y a Ba4CuBiO 10 A method for improving the performance of SmBCO superconducting bulk materials by nanoparticle doping, characterized in that, Includes the following steps: 1) The (Sm) as described in claim 2 2-a Y a Ba4CuBiO 10 Preparation of nanopowders 2) Preparation of seed crystals 2.1) Preparation of Nd2O3 powder: Nd2O3, BaCO3, and CuO powders were mixed uniformly in a molar ratio of 1:4:

6. The mixture was then subjected to three sintering processes at 910℃ using a solid-state reaction method, followed by four ball milling processes to produce NdBa2Cu3O3. 7-δ Abbreviation: Nd123 powder; 2.2) Preparation of Nd211 powder: Nd2O3, BaCO3 and CuO powders were mixed evenly in a molar ratio of 1:1:

1. The mixture was then sintered three times and ball-milled four times at 920℃ using a solid-state reaction method to produce Nd2BaCuO5, abbreviated as Nd211 powder. 2.3) Finally, Nd123 powder and Nd211 powder are mixed at a mass ratio of 3:1, and then 8wt% MgO powder is added and mixed evenly. The evenly mixed powder is weighed and pressed into NdBCO precursor blocks of equal diameter. NdBCO bulk material is obtained by growing it in a crystal growth furnace. Naturally cleaved NdBCO cubes are taken as NdBCO seed crystals. 3) Preparation of BaCuO2 powder BaCO3 and CuO were mixed evenly in a molar ratio of 1:1, and BaCuO2 powder was prepared by solid-state reaction at 897℃, 900℃ and 903℃ respectively, and sintered at least three times and ball-milled at least four times. 4) Preparation of solid-liquid phase 4.1) Preparation of solid-phase precursor blocks The solid-phase source powder is composed of the following components: (100-x)(Sm₂O₃+1.2BaCuO₂)+x(Sm 2-a Y a Ba4CuBiO 10 The powder of (x = 0, 1, 3, 5, 7, 9 wt%) + 1 wt% CeO2 was mixed evenly with a ball mill and a mortar and used as a solid source. It was then pressed into a cylindrical blank, and the solid precursor block was prepared. 4.2) Preparation of liquid phase precursor blocks The liquid phase source powder is formed by uniformly mixing Y2O3, BaCuO2 and CuO2 powders in a molar ratio of 1:10:

6. After uniform mixing, it is used as a liquid phase source and pressed into a cylindrical blank, thus completing the preparation of the liquid phase precursor block. 5) Assemble the solid-liquid phase 5.1) Prepare several MgO single crystal blocks and Al2O3 spacers; 5.2) Stack the liquid phase precursor block and the solid phase precursor block in an axisymmetric manner: First, place an appropriate number of MgO single crystals on the Al2O3 pad; Second, place the liquid phase precursor block and the solid phase precursor block in sequence from bottom to top on the surface of the MgO single crystals; Third, place the prepared NdBCO seed crystal at the center of the upper surface of the solid phase precursor block, and make the ab plane of the NdBCO seed crystal parallel to the surface of the solid phase precursor block. 6) Sample growth and oxygen permeation 6.1) Heat treatment procedure: Place the assembled solid-liquid phase billet from step 5) into a high-temperature furnace. First, heat the furnace to 850°C at a rate of 120°C / h and hold for 10 hours. Then, rapidly raise the temperature to 1070°C at a rate of 150°C / h and hold for 1.5 hours. Then, cool the furnace to 1060°C at a rate of 60°C / h. Then, begin slow cooling growth at a rate of 0.5°C / h to 1044°C. Finally, cool the furnace to room temperature. 6.2) Oxygen infiltration treatment: The grown single-domain SmBCO block is placed in an oxygen infiltration furnace, and then oxygen is introduced into the single-domain SmBCO block at a flow rate of 200 ml / min. It is heated to 290℃, then slowly cooled to 270℃, and then held at that temperature for 200 h. The block is then cooled to room temperature at a rate of 90℃ / h, and finally SmBCO superconducting block is obtained by transforming the tetragonal phase without superconductivity into an orthorhombic phase with superconductivity.

6. The method according to claim 5 via (Sm) 2-a Y a Ba4CuBiO 10 A method for improving the performance of SmBCO superconducting bulk materials by nanoparticle doping, characterized in that, The support block is a cylindrical blank made by pressing 5g of Y2O3 powder.

7. The method according to claim 5 via (Sm) 2-a Y a Ba4CuBiO 10 A method for improving the performance of SmBCO superconducting bulk materials by nanoparticle doping, characterized in that, In step 5.2), secondly, a support block, a liquid phase precursor block, and a solid phase precursor block are placed sequentially from bottom to top on the surface layer of the upper part of the MgO single crystal.

8. The method according to claim 5 via (Sm) 2-a Y a Ba4CuBiO 10 A method for improving the performance of SmBCO superconducting bulk materials by nanoparticle doping, characterized in that, In step 4.1), the weight is 15g and the diameter of the cylindrical blank is 20mm; in step 4.2), the weight is 27g and the diameter of the cylindrical blank is 30mm.

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