Ytterbium-doped iron selenium tellurium superconducting material and preparation method and application thereof

Abstract

The invention provides an ytterbium-doped iron selenium tellurium superconducting material and a preparation method and application thereof, the superconducting material comprises an iron element, an ytterbium element, a selenium element and a tellurium element, and the molar ratio of the iron element to the ytterbium element to the selenium element to the tellurium element in the superconducting material is (0.5-1.5): (0.01-0.1): (0.1-1): (0.1-1). A solid-phase sintering process is adopted, the sintering procedure is improved, the total sintering time is shortened to about 60 hours, and the preparation efficiency of the superconducting material is improved. And the prepared superconducting material is good in uniformity and high in density. In addition, the doping of the ytterbium element can promote the phase formation of the FeSeTe tetragonal phase and make the phase formation more uniform, improve the superconductive upper transition temperature, reduce the superconductive transition temperature width, and improve the superconductive performance of the superconductive phase body.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature superconducting material preparation methods, and in particular relates to ytterbium-doped iron-selenium-tellurium superconducting materials, preparation methods and uses thereof. Background Art

[0002] In 2008, Japanese scientists discovered superconductivity at 26K in LaFeAsO1-xFx, which opened up the research of iron-based superconductors. In the same year, Hsu et al. discovered a new iron-based superconducting material, FeSe. The superconducting layer of FeSe-based superconducting material is composed only of -FeSe- layers. It is the simplest iron-based superconducting material known so far, and its superconducting upper transition temperature is 8K. In order to increase the superconducting upper transition temperature, Te, which is in the same family as Se, is doped into FeSe, and the superconducting upper transition temperature is increased to 15K. So far, FeSeTe superconducting material has become an important component of iron-based superconductors.

[0003] In order to improve the superconducting properties of FeSe-based superconducting materials, researchers have developed a variety of effective measures. High-energy ball milling treatment of precursor powders, improved sintering procedures, annealing in different atmospheres, immersion treatment in different liquids, etc. Although different methods are helpful for phase formation and removal of interstitial iron, none of them start from the material itself. Therefore, consider doping the powder in order to improve the superconducting properties of FeSeTe from the chemical element composition. Previous doping can be divided into metal and non-metal doping. Metal doping is often concentrated in elements in the same period as Fe, such as Cr, Mn, CO, Ni, etc., all of which show a slight improvement or suppression of superconducting properties. The superconducting transition width of the sintered polycrystalline bulk is relatively large, the phase formation process is complex, the phase formation is uneven, and it is easy to produce impurities. Therefore, exploring new metal element doping has become an effective way to improve the superconducting properties of FeSeTe. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an ytterbium-doped iron selenium telluride superconducting material and a preparation method and use thereof, so as to solve the problems in the prior art.

[0005] A first aspect of the present invention provides an ytterbium-doped iron-selenium-tellurium superconducting material, wherein the superconducting material comprises iron, ytterbium, selenium and tellurium, and the molar ratio of the iron, ytterbium, selenium and tellurium in the superconducting material is (0.5-1.5): (0.01-0.1): (0.1-1): (0.1-1).

[0006] Preferably, the molar ratio of iron, ytterbium, selenium and tellurium in the superconducting material is (0.9-1.1):(0.01-0.1):(0.1-0.5):(0.3-0.8).

[0007] Further preferably, the molar ratio of iron, ytterbium, selenium and tellurium in the superconducting material is (0.95-1.05): (0.01-0.05): (0.2-0.5): (0.5-0.8).

[0008] Preferably, the superconducting upper transition temperature of the superconducting material is ≥14.5K; and / or the transition temperature width of the superconducting material is ≤2.5K.

[0009] In some preferred embodiments of the present invention, the superconducting upper transition temperature of the superconducting material is ≥15K; and / or the transition temperature width of the superconducting material is ≤2K.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned ytterbium-doped iron selenium telluride superconducting material, comprising the following steps:

[0011] 1) mixing iron powder, selenium powder, tellurium powder and ytterbium powder uniformly to obtain a mixed powder;

[0012] 2) Under a protective gas atmosphere, the mixed powder in step 1) is pressed into a block and vacuum-sealed in a quartz tube;

[0013] 3) The sealed quartz tube is sintered for the first time at 400-850°C for 50-60 hours;

[0014] 4) taking out the block after the first sintering and grinding it into powder;

[0015] 5) Under a protective gas atmosphere, the powder in step 4) is pressed into a block and vacuum-sealed in a quartz tube;

[0016] 6) The sealed quartz tube is sintered for a second time at 400-850°C for 50-60 hours.

[0017] The present invention adopts secondary sintering to reduce the gaps in the middle of the material after primary sintering, making the material more uniform and dense.

[0018] Preferably, the purity of the iron powder, selenium powder, tellurium powder and ytterbium powder is ≥ 99.9%

[0019] Preferably, the protective gas is one or both of nitrogen or inert gas.

[0020] More preferably, the protective gas is argon.

[0021] Preferably, the pressing pressure in the above step 2) and step 5) is 3 MPa to 8 MPa, and the pressing time is 10 min to 30 min.

[0022] Preferably, the vacuum degree in the above steps 2) and 5) is ≤5×10- 4Pa.

[0023] Preferably, the first sintering in the above step 3) is carried out by a three-step sintering method, comprising the following steps:

[0024] 1) Place the sealed quartz tube in a sintering furnace and heat it to 450℃~500℃ at a rate of 0.5~1℃ / min and sinter it at this temperature for 2h~4h;

[0025] 2) Continue to raise the temperature to 800-850°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 35-45h;

[0026] 3) Continue to cool down to 400-450°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 0.2-1h.

[0027] Preferably, the second sintering in the above step 6) adopts a three-step sintering method, comprising the following steps:

[0028] 1) Place the sealed quartz tube in a sintering furnace and heat it to 450℃~500℃ at a rate of 0.5~1℃ / min and sinter it at this temperature for 2h~4h;

[0029] 2) Continue to raise the temperature to 600-700°C at a rate of 0.5°C / min-2°C / min and sinter at this temperature for 35-45h;

[0030] 3) Continue to cool down to 400-450°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 0.2-1h.

[0031] The present invention adopts a lower heating rate in the first step of the three-step sintering method to prevent the increase of vapor pressure of selenium due to excessively fast heating, which may cause the quartz tube used for sealing to break, and also prevent the rapid vaporization and escape of selenium from the block, which may cause holes in the block or uneven surface.

[0032] Preferably, the method further comprises a cooling step, wherein the cooling step is to naturally cool the quartz tube carrying the block to 20-30° C. after the first sintering and the second sintering.

[0033] A third aspect of the present invention provides a use of the superconducting material as claimed in claims 1 to 2 as a sputtering target.

[0034] As described above, the ytterbium-doped iron-selenium-tellurium superconducting material of the present invention and its preparation method and use have the following beneficial effects:

[0035] 1. The present invention adopts a solid phase sintering process and adjusts the sintering temperature and sintering time to uniformly dope the ytterbium element into the iron selenium telluride superconducting material to prepare a block with good uniformity and high density.

[0036] 2. The present invention adopts a solid phase sintering process and improves the sintering procedure, reducing the total sintering time to about 60 hours, thereby improving the preparation efficiency of superconducting materials.

[0037] 3. The doping of ytterbium can promote the formation of FeSeTe tetragonal phase and make the formation more uniform. While maintaining a high superconducting upper transition temperature, it can reduce the superconducting transition temperature width and improve the superconducting performance of the superconducting phase.

[0038] 4. Ytterbium, as a non-superconducting particle, can serve as an effective pinning source and can also indirectly form defects in superconducting materials, providing more abundant pinning types and improving superconducting current density. The above different aspects work together to effectively improve the superconducting performance of FeSeTe targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It shows that the Fe 0.96 Yb 0.04 Se 0.4 Te 0.6 The resistance-temperature curve of a superconducting material.

[0040] Figure 2 It shows that the Fe 1.0 Yb 0.02 Se 0.4 Te 0.6 X-ray diffraction pattern of superconducting materials.

[0041] Figure 3 The Fe prepared in Example 3 of the present invention 1.0 Yb 0.04 Se 0.4 Te 0.6 The resistance-temperature curve of a superconducting material. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before or after the combination step or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before or after the combination device / apparatus or the insertion of other devices / apparatuses between these explicitly mentioned two devices / apparatuses, unless otherwise specified. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0044] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing the specific embodiments rather than for limiting the scope of protection of the present invention; in the present specification and claims, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0045] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0046] Example 1

[0047] This embodiment 1 provides a method for preparing an ytterbium-doped iron-selenium-telluride superconducting material, which specifically includes the following steps:

[0048] Step 1: In an argon-protected glove box, iron powder, ytterbium powder, selenium powder and tellurium powder are mixed uniformly according to a molar ratio of 0.96:0.04:0.4:0.6 to obtain a mixed powder with a total mass of 2 g. The purity of the above iron powder, ytterbium powder, selenium powder and tellurium powder is not less than 99.9%.

[0049] Step 2: In an argon-protected glove box, the mixed powder is placed in a mold with an inner diameter of 0.5 inches, and the powder is pressed into shape using a cold-pressing tablet press at a pressure of 6 MPa for 10 min to obtain a compact.

[0050] Step 3: In an argon-protected glove box, the compact prepared in step 2 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0051] Step 4: Place the sealed quartz tube containing the pressed block into a tube furnace for sintering, specifically in accordance with the following treatment: 10 hours to 500 ° C and sinter at 500 ° C for 3 hours; 2 hours to 800 ° C and keep at 800 ° C for 39 hours; 2 hours to 450 ° C and keep at 450 ° C for 1 hour, the total treatment time is 57 hours. The furnace is cooled to room temperature.

[0052] Step 5: In an argon-protected glove box, break the sintered quartz tube, take out the block and grind it evenly to obtain a powder, put the powder into a mold with an inner diameter of 0.5 inches, and press the powder into shape using a cold pressing tablet press at a pressure of 4 MPa for 10 min to obtain a compact.

[0053] Step 6: In an argon-protected glove box, the compact prepared in step 5 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0054] Step 7: Place the sealed quartz tube containing the pressed block in step 6 into a tube furnace for sintering. The specific treatment is as follows: heat up to 500℃ for 10 hours and sinter at 500℃ for 3 hours; heat up to 700℃ for 2 hours and keep at 700℃ for 39 hours; cool down to 450℃ for 2 hours and keep at 450℃ for 1 hour. The total treatment time is 57 hours. After the furnace is cooled to room temperature, the iron selenium telluride superconducting material is obtained, and its chemical formula is Fe 0.96 Yb 0.04 Se 0.4 Te 0.6 .

[0055] The Fe prepared in Example 1 0.96 Yb 0.04 Se 0.4 Te 0.6 Superconducting performance test, its resistance-temperature curve is as follows Figure 1 As shown. Figure 1 It can be seen that the Fe prepared in Example 1 0.96 Yb 0.04 Se 0.4 Te 0.6The superconducting upper transition temperature is 15K, and the superconducting transition temperature width is within 2K.

[0056] Example 2

[0057] On the basis of Example 1, this Example 2 further modifies the molar ratio of iron powder, ytterbium powder, selenium powder and tellurium powder to: 1:0.02:0.4:0.6, and specifically includes the following steps:

[0058] Step 1: In an argon-protected glove box, iron powder, ytterbium powder, selenium powder and tellurium powder are mixed evenly in a molar ratio of 1:0.02:0.4:0.6 to obtain a mixed powder with a total mass of 2 g. The purity of the above iron powder, ytterbium powder, selenium powder and tellurium powder is not less than 99.9%.

[0059] Step 2: In an argon-protected glove box, the mixed powder is placed in a mold with an inner diameter of 0.5 inches, and the powder is pressed into shape using a cold-pressing tablet press at a pressure of 6 MPa for 10 min to obtain a compact.

[0060] Step 3: In an argon-protected glove box, the compact prepared in step 2 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0061] Step 4: Place the sealed quartz tube containing the pressed block into a tube furnace for sintering, specifically in accordance with the following treatment: 10 hours to 500 ° C and sinter at 500 ° C for 3 hours; 2 hours to 800 ° C and keep at 800 ° C for 39 hours; 2 hours to 450 ° C and keep at 450 ° C for 1 hour, the total treatment time is 57 hours. The furnace is cooled to room temperature.

[0062] Step 5: In an argon-protected glove box, break the sintered quartz tube, take out the block and grind it evenly to obtain a powder, put the powder into a mold with an inner diameter of 0.5 inches, and press the powder into shape using a cold pressing tablet press at a pressure of 4 MPa for 10 min to obtain a compact.

[0063] Step 6: In an argon-protected glove box, the compact prepared in step 5 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0064] Step 7: Place the sealed quartz tube containing the pressed block in step 6 into a tube furnace for sintering. The specific treatment is as follows: heat up to 500℃ for 10 hours and sinter at 500℃ for 3 hours; heat up to 650℃ for 2 hours and keep at 650℃ for 39 hours; cool down to 450℃ for 2 hours and keep at 450℃ for 1 hour. The total treatment time is 57 hours. After the furnace is cooled to room temperature, the iron selenium telluride superconducting material is obtained, and its chemical formula is Fe 1.0 Yb 0.02 Se 0.4 Te 0.6 .

[0065] The Fe prepared in Example 2 1.0 Yb 0.02 Se 0.4 Te 0.6 X-ray diffraction test was performed, and the X-ray diffraction pattern was as follows Figure 2 As shown. Figure 2 It can be seen that the Fe prepared in Example 2 1.0 Yb 0.02 Se 0.4 Te 0.6 Only the diffraction peak of the FeSeTe tetragonal phase appears, and there is no impurity phase, which shows that the doping of Yb does not produce impurities and does not deteriorate the crystal quality. In addition, the addition of ytterbium promotes the formation of the FeSeTe tetragonal phase and makes the phase formation more uniform.

[0066] Example 3

[0067] On the basis of Example 1, this Example 3 further modifies the molar ratio of iron powder, ytterbium powder, selenium powder and tellurium powder to: 1:0.04:0.4:0.6, and specifically includes the following steps:

[0068] Step 1: In an argon-protected glove box, iron powder, ytterbium powder, selenium powder and tellurium powder are mixed evenly in a molar ratio of 1:0.04:0.4:0.6 to obtain a mixed powder with a total mass of 2 g. The purity of the above iron powder, ytterbium powder, selenium powder and tellurium powder is not less than 99.9%.

[0069] Step 2: In an argon-protected glove box, the mixed powder is placed in a mold with an inner diameter of 0.5 inches, and the powder is pressed into shape using a cold-pressing tablet press at a pressure of 6 MPa for 10 min to obtain a compact.

[0070] Step 3: In an argon-protected glove box, the compact prepared in step 2 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0071] Step 4: Place the sealed quartz tube containing the pressed block into a tube furnace for sintering, specifically in accordance with the following treatment: 10 hours to 500 ° C and sinter at 500 ° C for 3 hours; 2 hours to 800 ° C and keep at 800 ° C for 39 hours; 2 hours to 450 ° C and keep at 450 ° C for 1 hour, the total treatment time is 57 hours. The furnace is cooled to room temperature.

[0072] Step 5: In an argon-protected glove box, break the sintered quartz tube, take out the block and grind it evenly to obtain a powder, put the powder into a mold with an inner diameter of 0.5 inches, and press the powder into shape using a cold pressing tablet press at a pressure of 4 MPa for 10 min to obtain a compact.

[0073] Step 6: In an argon-protected glove box, the compact prepared in step 5 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0074] Step 7: Place the sealed quartz tube containing the pressed block in step 6 into a tube furnace for sintering. The specific treatment is as follows: heat up to 500℃ for 10 hours and sinter at 500℃ for 3 hours; heat up to 700℃ for 2 hours and keep at 700℃ for 39 hours; cool down to 450℃ for 2 hours and keep at 450℃ for 1 hour. The total treatment time is 57 hours. After the furnace is cooled to room temperature, the iron selenium telluride superconducting material is obtained, and its chemical formula is Fe 1.0 Yb 0.04 Se 0.4 Te 0.6 .

[0075] The Fe prepared in Example 3 1.0 Yb 0.04 Se 0.4 Te 0.6 Superconducting performance test, its resistance-temperature curve is as follows Figure 3 As shown. Figure 3 It can be seen that the Fe prepared in Example 3 1.0 Yb 0.04 Se 0.4 Te 0.6 The superconducting upper transition temperature is 14.5K, and the superconducting transition temperature width is within 2.5K.

[0076] Comparative Example 1

[0077] On the basis of Example 1, in this comparative example 1, ytterbium powder is replaced with manganese powder to prepare manganese-doped iron-selenium-tellurium superconducting material, which specifically includes the following steps:

[0078] Step 1: In an argon-protected glove box, iron powder, manganese powder, selenium powder and tellurium powder are mixed uniformly in a molar ratio of 0.96:0.04:0.4:0.6 to obtain a mixed powder with a total mass of 2 g. The purity of the above iron powder, manganese powder, selenium powder and tellurium powder is not less than 99.9%.

[0079] Step 2: In an argon-protected glove box, the mixed powder is placed in a mold with an inner diameter of 0.5 inches, and the powder is pressed into shape using a cold-pressing tablet press at a pressure of 6 MPa for 10 min to obtain a compact.

[0080] Step 3: In an argon-protected glove box, the compact prepared in step 2 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0081] Step 4: Place the sealed quartz tube containing the pressed block into a tube furnace for sintering, specifically in accordance with the following treatment: heating to 500°C for 10 hours and sintering at 500°C for 3 hours; heating to 800°C for 2 hours and keeping at 800°C for 39 hours; cooling to 450°C for 2 hours and keeping at 450°C for 1 hour, the total treatment time is 57 hours. Naturally cool to room temperature.

[0082] Step 5: In an argon-protected glove box, break the sintered quartz tube, take out the block and grind it evenly to obtain a powder, put the powder into a mold with an inner diameter of 0.5 inches, and press the powder into shape using a cold pressing tablet press at a pressure of 4 MPa for 10 min to obtain a compact.

[0083] Step 6: In an argon-protected glove box, the compact prepared in step 5 was placed in a customized quartz tube with a reduced neck and fixed at the reduced neck with a cylindrical quartz plug. The tube was fixed on a tube sealing machine and the quartz tube was evacuated to a vacuum degree of no more than 1×10 -4 Pa, stop evacuating the tube and use a hydrogen-oxygen torch to seal the quartz plug.

[0084] Step 7: Place the sealed quartz tube containing the pressed block in step 6 into a tube furnace for sintering. The specific treatment is as follows: heat up to 500℃ for 10 hours and sinter at 500℃ for 3 hours; heat up to 700℃ for 2 hours and keep at 700℃ for 39 hours; cool down to 450℃ for 2 hours and keep at 450℃ for 1 hour. The total treatment time is 57 hours. After the furnace is cooled to room temperature, the iron selenium telluride superconducting material is obtained, and its chemical formula is Fe 0.96 Mn 0.04 Se 0.4 Te 0.6 .

[0085] The superconducting performance of the highly doped FeSeTe superconducting material prepared in Comparative Example 1 was tested. The resistance starting transition temperature of the material was less than 12K, and the superconducting transition temperature width was greater than 3K.

[0086] Compared with the manganese-doped iron selenium telluride superconducting material of comparative example 1, the starting transition temperature of the ytterbium-doped iron selenium telluride superconducting material prepared in the present application is greater than 12K, and the superconducting transition temperature width is less than 2.5K. It is proved that the ytterbium-doped iron selenium telluride superconducting material prepared in the present application has a smaller superconducting transition temperature width and higher superconducting performance. In addition, compared with Example 1, the increase in the molar ratio of iron in Example 3 will make its superconducting temperature lower and the superconducting transition temperature width wider, which is not conducive to the improvement of the superconductivity of the material.

[0087] In summary, the ytterbium-doped iron selenium telluride superconducting material prepared in this application has excellent electrical conductivity. Ytterbium doping can promote the formation of FeSeTe tetragonal phase and make the formation more uniform, reduce the superconducting transition temperature width, and improve the superconducting performance of the superconducting phase. In addition, ytterbium elements as non-superconducting particles can be used as effective pinning sources and can also indirectly form defects in superconducting materials, providing more abundant pinning types and improving superconducting current density. The above different aspects work together to effectively improve the superconducting performance of FeSeTe target materials.

[0088] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and evolutions of the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An ytterbium-doped iron selenium telluride superconducting material, characterized in that: The superconducting material includes iron, ytterbium, selenium and tellurium, and the molar ratio of the iron, ytterbium, selenium and tellurium in the superconducting material is (0.5-1.5): (0.01～0.1)：(0.1～1)：(0.1～1)。 2. The superconducting material according to claim 1, characterized in that The superconducting upper transition temperature of the superconducting material is ≥14.5K; And / or, the transition temperature width of the superconducting material is ≤2.5K.

3. A method for preparing the ytterbium-doped iron selenium telluride superconducting material according to claim 1 or 2, characterized in that: The steps include: 1) mixing iron powder, selenium powder, tellurium powder and ytterbium powder uniformly to obtain a mixed powder; 2) Under a protective gas atmosphere, the mixed powder in step 1) is pressed into a block and vacuum-sealed in a quartz tube; 3) The sealed quartz tube is sintered for the first time at 400-850°C for 50-60 hours; 4) taking out the block after the first sintering and grinding it into powder; 5) Under a protective gas atmosphere, the powder in step 4) is pressed into a block and vacuum-sealed in a quartz tube; 6) The sealed quartz tube is sintered for a second time at 400-850°C for 50-60 hours.

4. The preparation method according to claim 3, characterized in that: The protective gas is one or both of nitrogen and inert gas; preferably, the protective gas is argon.

5. The preparation method according to claim 3, characterized in that: The pressing pressure in step 2) and step 5) is 3MPa to 8MPa, and the pressing time is 10min to 30min.

6. The complete subject name according to claim 3, characterized in that: The vacuum degree in step 2) and step 5) is ≤5×10 -4 Pa.

7. The preparation method according to claim 3, characterized in that: The first sintering in step 3) adopts a three-step sintering method, including the following steps: 1) Place the sealed quartz tube in a sintering furnace and heat it to 450°C to 500°C at a rate of 0.5 to 1°C / min and sinter at this temperature for 2h to 4h; 2) Continue to raise the temperature to 800-850°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 35-45h; 3) Continue to cool down to 400-450°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 0.2-1h.

8. The preparation method according to claim 3, characterized in that: The second sintering in step 6) adopts a three-step sintering method, including the following steps: 1) Place the sealed quartz tube in a sintering furnace and heat it to 450°C to 500°C at a rate of 0.5 to 1°C / min and sinter at this temperature for 2h to 4h; 2) Continue to raise the temperature to 600-700°C at a rate of 0.5°C / min-2°C / min and sinter at this temperature for 35-45h; 3) Continue to cool down to 400-450°C at a rate of 2°C / min-3°C / min and sinter at this temperature for 0.2-1h.

9. The preparation method according to claim 3, characterized in that: The method further comprises a cooling step, wherein the cooling step is to naturally cool the quartz tube loaded with the block to 20-30° C. after the first sintering and the second sintering.

10. Use of the superconducting material according to any one of claims 1 to 2 as a sputtering target.

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