A rare earth hydride superconducting material and a method for producing the same

Abstract

The application discloses a rare earth hydride superconducting material and a preparation method thereof, and belongs to the technical field of superconducting materials. The rare earth hydride superconducting material is used to solve the problem that existing hydride superconducting systems are concentrated in high-hydrogen material systems and have small improvement space for superconducting transition temperature. x The chemical formula of the rare earth hydride superconducting material is REH x<6; RE is one of rare earth elements; or RE is one of lutetium and yttrium; and x<6. The rare earth hydride superconducting material further comprises a non-metallic doping element. The rare earth hydride superconducting material enriches the hydrogen-based superconducting material family. The non-metallic doping element is used to dope the rare earth hydride superconducting material, so that the superconducting transition temperature of the material is improved, and a direction for searching for a new high-temperature hydrogen-based superconducting material is provided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of superconducting materials. Specifically, it relates to a rare earth hydride superconducting material and a preparation method thereof. BACKGROUND

[0002] Metallic hydrogen has been a physical "holy grail" that researchers have been pursuing tirelessly. According to the Bardeen-Cooper-Schrieffer (BCS) theory, the higher the Debye temperature, the higher the superconducting transition temperature. The Debye temperature is directly proportional to the upper limit of the vibration frequency, that is, the lighter the element, the higher the vibration frequency, and the higher the Debye temperature. The theory predicts that hydrogen molecular crystals may be converted into metallic hydrogen under high pressure conditions to achieve room-temperature superconductivity. In recent years, with the development of T-type diamond anvil, high-pressure technology can achieve ultra-high pressure of 600 GPa. In 2017, R.P. Dias et al. of Harvard University reported that metallic luster of hydrogen was observed at 495 GPa. Since the aluminum oxide used to suppress the diffusion of hydrogen in the diamond anvil device may also be converted into metal under such high pressure, which has a serious impact on the determination of the experimental results, this phenomenon has been controversial since the report. Researchers in the field of high pressure generally believe that higher pressure is needed to achieve metallic hydrogen.

[0003] In 2004, Ashcroft proposed the concept of "chemical pre-compression", that is, the sublattice of hydrogen in hydride is "pre-compressed", and hydrogen metalization is achieved at a lower pressure by preparing hydrogen-rich materials. Based on this idea, in recent years, theoretical and experimental researches on hydrogen-based superconducting materials have made some achievements. A series of high-temperature superconductors such as LaH 10 , YH6, YH9, CeH9, etc. with hydrogen cage structure have been reported by experimental groups. The superconducting transition temperature of these hydrogen-based superconductors has gradually approached room temperature, and the successful development of hydrogen-rich materials shows great potential in high-temperature superconductivity.

[0004] Currently, the research on hydrogen-based high-temperature superconductors mainly focuses on rare earth element multi-hydrogen systems, that is, REH x (x≥6), and the development and preservation of these multi-hydrogen superconductors often require extremely high pressure. From the perspective of the development of high-pressure technology and the application of metallic hydrogen, exploring hydrogen-based superconducting materials with lower hydrogen content and reducing the preparation pressure has become an important direction for the development and application of superconducting materials. In addition, existing experiments mainly focus on the influence of rare earth metal doping on the superconducting properties of their hydrides, and the results show that the improvement of superconducting properties and material stability before and after doping is not ideal. Therefore, the research on rare earth hydride superconducting materials is still a problem to be solved. SUMMARY

[0005] The application aims to provide a rare earth hydride superconducting material and a preparation method thereof, and solve the problem that the existing hydride superconducting system is concentrated in high hydrogen material system and has small improvement space for superconducting transition temperature.

[0006] The above-mentioned purpose of the application is achieved by the following technical scheme:

[0007] In one aspect, the application provides a rare earth hydride superconducting material, and the chemical formula of the rare earth hydride superconducting material is REH x ;

[0008] RE is one of rare earth elements; or RE is one of lutetium and yttrium;

[0009] x is the atomic ratio of H to RE, and x < 6.

[0010] Further, the rare earth hydride superconducting material further comprises a non-metallic doping element, that is, the chemical formula of the rare earth hydride superconducting material is REH x’ R y ;

[0011] R is one or more of B, C and N;

[0012] x' is the atomic ratio of H to RE, and x' < 6;

[0013] y is the doping atomic ratio of the doping element to H, and 0 < y ≤ 30%.

[0014] Further, the above-mentioned rare earth hydride superconducting material has a superconducting transition temperature of 55K or higher.

[0015] In another aspect, the application further provides a preparation method of a rare earth hydride superconducting material, comprising the following steps:

[0016] S1, encapsulating a hydrogen source material and a rare earth element or a hydrogen source material, a rare earth element and a doping element raw material into a high-pressure cavity;

[0017] S2, pressurizing the raw materials in the high-pressure cavity to a target pressure, then starting to heat to a target temperature, and keeping pressure and temperature, to obtain the rare earth hydride superconducting material; the target pressure is 100-220GPa, and the target temperature is 50-2000℃;

[0018] The rare earth hydride superconducting material has a superconducting transition temperature of 55K or higher.

[0019] Further, in S1, the hydrogen source material and the doping element raw material exist in a gaseous or solid state.

[0020] Further, in S1 and S2, the target temperature when the hydrogen source material and the doping element raw material exist in a gaseous form is lower than the target temperature when the hydrogen source material and the doping element raw material exist in a solid form.

[0021] Further, S1 further includes completing the preparation work of the high-pressure device, and the preparation work includes:

[0022] S01. According to the anvil area of the high-pressure device, a matching gasket is selected and pre-pressed to make a pressure mark at the center position of the gasket, or a suitable sample cavity is selected according to the type of the high-pressure device;

[0023] S02. Then, a hole is punched at the pressure mark center position of the gasket, and the hole is a high-pressure cavity for sample packaging and reaction;

[0024] S03. Then, the gasket is fixed at the pressure mark position of the lower anvil surface of the high-pressure device;

[0025] S04. The relative positions of the upper anvil, the gasket and the lower anvil are fixed, and a certain distance is maintained between the upper anvil and the lower anvil for packaging of the gaseous raw material.

[0026] Further, the high-pressure device is selected from a multi-face top press, a two-face top press or a ring press.

[0027] Further, in S1, the packaging pressure is 0.5-10 GPa.

[0028] Further, in S1, the rare earth element raw material is placed in the high-pressure cavity in the form of a thin film.

[0029] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0030] 1) The preparation method of the present application can prepare a new type of rare earth hydride superconducting material by accurately controlling the pressure and temperature, and the atomic ratio of hydrogen to rare earth elements in the rare earth hydride superconducting material is less than 6. Through testing the rare earth hydride superconducting material of the present application under high pressure conditions, it has a superconducting transition temperature of more than 55K, which enriches the family of hydrogen-based superconducting materials.

[0031] 2) The present application uses non-metallic elements to dope the above-mentioned rare earth hydride superconducting material, which effectively reduces the preparation pressure of the superconducting material and improves the superconducting transition temperature of the material, providing a direction for finding new high-temperature hydrogen-based superconducting materials.

[0032] Other features and advantages of the present application will be set forth in the examples below, and some can be apparent from the description, or can be learned by practicing the present application. The objects and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0034] Figure 1 A physical diagram of placing a sample based on a diamond anvil device of the present application;

[0035] Figure 2 An X-ray diffraction spectrum of a rare earth hydride superconducting material of Example 1 of the present application;

[0036] Figure 3 A graph of resistance vs. temperature of a rare earth hydride superconducting material of Example 1 of the present application;

[0037] Figure 4 An X-ray diffraction spectrum of a rare earth hydride superconducting material of Example 2 of the present application;

[0038] Figure 5 A graph of resistance vs. temperature of a rare earth hydride superconducting material of Example 2 of the present application;

[0039] Figure 6 A graph of superconducting transition temperature vs. N doping amount of a rare earth hydride superconducting material of Example 3 of the present application;

[0040] Figure 7 A graph of resistance vs. temperature of a rare earth hydride superconducting material of Example 4 of the present application;

[0041] Figure 8 A graph of resistance vs. temperature of a rare earth hydride superconducting material of Example 6 of the present application. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present application will be described herein below with reference to the accompanying drawings, in which:

[0043] The present application provides a rare earth hydride superconducting material, the chemical formula of the rare earth hydride superconducting material is REH x ; wherein RE is one of rare earth elements; specifically, RE is one of lutetium and yttrium; x < 6. For example, x is 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 5.75.

[0044] The above rare earth hydride superconducting material is tested under high pressure conditions and has a superconducting transition temperature of 55K or above.

[0045] Specifically, in order to further improve the superconducting transition temperature of the rare earth hydride superconducting material, a non-metallic doping element is further included in the rare earth hydride superconducting material, that is, the chemical formula of the rare earth hydride superconducting material is REH x’ R y ; wherein R is one or more of B, C and N; x' is the atomic ratio of H to RE, x' < 6, for example, x' is 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 5.5, 5.6, 5.7, etc. y is the atomic ratio of the doping element to H, 0 < y ≤ 30%, for example, y is 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, etc.

[0046] The rare earth hydride superconducting material is tested under high pressure conditions and has a superconducting transition temperature of 55K or higher.

[0047] Specifically, the inventors have found that doping the rare earth hydride superconducting material with a non-metallic element can broaden the hydrogen energy band and raise the position of the hydrogen energy band to the Fermi surface, thereby exhibiting metallic properties. In addition, compressing the formed metallic material will reduce the pressure required for the hydrogen-based material to exhibit superconducting transition and increase the superconducting transition temperature.

[0048] On the other hand, the present application provides a preparation method of a rare earth hydride superconducting material, comprising the following steps:

[0049] S1, packaging a hydrogen source material and a rare earth element raw material into a high-pressure cavity;

[0050] S2, pressurizing the raw materials in the high-pressure cavity to a target pressure, then heating to a target temperature, and maintaining the pressure and temperature to prepare a rare earth hydride superconducting material.

[0051] Specifically, in the above S1, the hydrogen source material, the rare earth element raw material and the doping element raw material can also be packaged into the high-pressure cavity.

[0052] Specifically, the above S1 further comprises completing the preparation work of the high-pressure device, which includes:

[0053] S01. According to the anvil area of the high-pressure device, select a matching gasket and pre-press to make a pressure mark at the center of the gasket, or select a suitable sample cavity according to the type of the high-pressure device;

[0054] S02. Then, a hole is punched at the center of the pressure mark of the gasket, which is the high-pressure cavity for sample packaging and reaction;

[0055] S03. Then, the gasket is fixed at the indentation position of the anvil surface of the high-pressure device;

[0056] S05. The relative positions of the upper anvil, the gasket and the lower anvil are fixed, wherein a certain distance is maintained between the upper anvil and the lower anvil for the packaging of the conventional gaseous raw materials.

[0057] Specifically, the gasket is made of a metal material such as T301 stainless steel, metallic rhenium or metallic tungsten.

[0058] Specifically, the thickness of the gasket is 230-260 microns.

[0059] Specifically, in S01, the thickness of the indentation center is 16-22 microns.

[0060] Specifically, the punching is performed by laser punching or mechanical punching, and the aperture of the hole is 35-45 microns.

[0061] Specifically, the high-pressure device is selected from a multi-anvil press, a two-anvil press or a ring press.

[0062] Specifically, the multi-anvil press can be a six-anvil press.

[0063] Specifically, the two-anvil press can be a Paris-Edinburgh press or a diamond anvil device.

[0064] Specifically, in S1, the hydrogen source material and the doping element raw material can exist in gaseous or solid state; the solid-state raw material is in the form of powder placed in the high-pressure cavity; the gaseous raw material is in the form of a mixture of fixed components filled into the high-pressure cavity.

[0065] Specifically, in S1, the rare earth element raw material is deposited on the surface of the high-pressure anvil by a magnetron sputtering method, and is placed in the high-pressure cavity in the form of a thin film.

[0066] Specifically, in S1, the thickness of the rare earth element raw material thin film is 0.1-2 microns.

[0067] Specifically, the hydrogen source material can be hydrogen, ammonia borane and derivatives, and the doping element raw material can be nitrogen, azide, boron and elemental carbon.

[0068] Specifically, in S1, the raw material packaging pressure is 0.5-10 GPa, for example, 1 GPa, 1.5 GPa, 2 GPa, 2.5 GPa, 3 GPa, 3.5 GPa, 4 GPa, 4.5 GPa, 5 GPa, 5.5 GPa, 6 GPa, 6.5 GPa, 7 GPa, 7.5 GPa, 8 GPa, 8.5 GPa, 9 GPa, 9.5 GPa.

[0069] Specifically, in the above S2, the target pressure is 100-220 GPa, for example, 110 GPa, 120 GPa, 130 GPa, 140 GPa, 150 GPa, 160 GPa, 170 GPa, 180 GPa, 190 GPa. The target temperature is 50-2000℃, for example, 100℃, 200℃, 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃, 1900℃. The holding time is several minutes to several days, for example, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 1 h, 2 h, 5 h, 10 h, 15 h, 20 h, 1 day, 2 days, 3 days, etc.

[0070] Specifically, in the above S1 and S2, a solid hydrogen source material is used, and the prepared rare earth hydride superconducting material is Lu4H 23 When the target pressure is 190-220 GPa, the target temperature is 1800-2000℃, and the holding time is 5-10 minutes.

[0071] Specifically, in the above S1 and S2, a gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Lu4H 23 When the target pressure is 190-220 GPa, the target temperature is 800-1000℃, and the holding time is 1-2 hours.

[0072] Specifically, in the above S1 and S2, a solid hydrogen source material is used, and the prepared rare earth hydride superconducting material is LuH 3-n When the target pressure is 160-185 GPa, the target temperature is 1200-1500℃, and the holding time is 3-5 minutes.

[0073] Specifically, in the above S1 and S2, a gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is LuH 3-n When the target pressure is 160-185 GPa, the target temperature is 50-500℃, and the holding time is 1-20 hours.

[0074] Specifically, in the above S1 and S2, a solid hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 23The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0075] Specifically, in the above S1 and S2, the gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 23 The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0076] Specifically, in the above S1 and S2, the gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 23-m N y The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0077] Specifically, in the above S1 and S2, the gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 23-m N y The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0078] Specifically, in the above S1 and S2, the gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 3-m R y The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0079] Specifically, in the above S1 and S2, the gaseous hydrogen source material is used, and the prepared rare earth hydride superconducting material is Y4H 3-m R y The target pressure is 120-150 GPa, the target temperature is 1500-1800 DEG C, and the pressure maintaining and heat preserving time is 5-10 minutes.

[0080] Specifically, the non-metallic doping element is used to dope the REH x After doping, the preparation pressure of the superconducting material can be reduced, and the superconducting transition temperature of the material can be improved.

[0081] Embodiment 1

[0082] The embodiment provides a rare earth hydride superconducting material and a preparation method thereof. The chemical formula of the rare earth hydride superconducting material in the embodiment is Lu4H 23 .

[0083] The preparation method of the Lu4H 23 of the embodiment comprises the following steps:

[0084] S1, encapsulating a rare earth element raw material and a hydrogen source material into a high-pressure cavity of a diamond anvil device;

[0085] S2, using the diamond anvil device to pressurize the raw material in the high-pressure cavity, and after reaching a target pressure, starting to heat to a target temperature, and keeping pressure and temperature, to obtain the rare earth hydride superconducting material.

[0086] Specifically, the above S1 further comprises: completing the preparation work of the diamond anvil device, and the preparation work of the diamond anvil device comprises:

[0087] S01. According to the anvil area of the diamond anvil device, a matching gasket is selected and pre-pressed to make a pressure mark appear at the center position of the gasket;

[0088] S02. Then, a hole is punched at the center position of the pressure mark of the gasket, and the gasket is installed at the center position of the lower anvil surface of the diamond anvil.

[0089] Specifically, in the above S01, the material of the gasket is rhenium sheet.

[0090] Specifically, in the above S01, the thickness of the gasket is about 250 microns.

[0091] Specifically, in the above S01, the thickness of the gasket pressure mark center after pre-pressing is 20 microns.

[0092] Specifically, in the above S02, the punching can be performed by laser punching or mechanical punching.

[0093] Specifically, in the above S02, the aperture of the laser punching is 40 microns.

[0094] Specifically, in the above S1, the hydrogen source material is ammonia borane, which is in the form of powder and is placed in the high-pressure cavity.

[0095] Specifically, in the above S1, the metal material is high-purity metal lutetium, which is deposited on the upper surface of the diamond anvil by a magnetron sputtering method, and the thickness of the metal lutetium is 0.1-2 microns.

[0096] Specifically, in the above S1, the encapsulation pressure is 2 GPa.

[0097] Specifically, in the above S2, the pressurization is performed by a gear reduction pressurization device to press the piston cylinder, and the target pressure is 195 GPa.

[0098] Specifically, in the above S2, the heating of the raw material under high pressure can be performed by a laser heating method, and the target temperature is 1900℃.

[0099] Specifically, in the above S2, the pressure maintaining and temperature maintaining is performed for 8 minutes.

[0100] Specifically, as shown in Figure 1 is a physical diagram of placing a sample based on a diamond anvil device. The structure of the rare earth hydride superconducting material prepared in this embodiment is tested and analyzed, and as shown in Figure 2 is the X-ray diffraction spectrum of the rare earth hydride superconducting material of this embodiment, and it is confirmed that the chemical formula of the obtained rare earth hydride superconducting material is Lu4H 23 . By performing resistance testing under high pressure conditions, as shown in Figure 3 is a resistance-temperature change diagram of the rare earth hydride superconducting material of this embodiment, and it is found that the rare earth hydride superconducting material of this embodiment has a superconducting transition temperature of up to 71K.

[0101] Specifically, the Lu4H 23 of this embodiment belongs to a cubic crystal system, and the space group and lattice constant are and The shortest H-H distance of this material is under high pressure of 218 GPa has a superconducting transition temperature of 71K.

[0102] It should be noted that the inventors conducted a large number of experiments during the research process, and the pressure and temperature were not completely the same in different experimental processes, but as long as the target pressure is 190-220 GPa, the target temperature is 1800-2000℃, and the appropriate pressure maintaining and temperature maintaining time of 5-10 minutes are matched, the above-mentioned rare earth hydride superconducting material can be obtained.

[0103] Embodiment 2

[0104] The embodiment provides a rare earth hydride superconducting material and a preparation method thereof. The chemical formula of the rare earth hydride superconducting material in the embodiment is LuH 2.9 .

[0105] The preparation method of the Lu4H 23 of this embodiment has the same overall steps as those of embodiment 1, and the difference lies in that:

[0106] Specifically, in S02 above, the diameter of the laser-drilled hole is 50 micrometers.

[0107] Specifically, in S1 above, the thickness of the lutetium metal is 0.1 to 2 micrometers.

[0108] Specifically, in S2 above, the target pressure is 165 GPa.

[0109] Specifically, in S2 above, the target temperature is 1300℃.

[0110] Specifically, in S2 above, pressure and temperature are maintained for 5 minutes.

[0111] Specifically, the rare-earth hydride superconducting material prepared in this embodiment was subjected to structural testing and analysis, such as... Figure 4 The image shows the X-ray diffraction pattern of the rare-earth hydride superconducting material in this embodiment, confirming that the chemical formula of the obtained rare-earth hydride superconducting material is LuH. 2.9 Resistance testing is performed under high voltage conditions, such as... Figure 5 The graph shown is a graph of the resistance of the rare earth hydride superconducting material in this embodiment as a function of temperature. It is found that the rare earth hydride superconducting material in this embodiment has a superconducting transition temperature of up to 58K.

[0112] Specifically, the space group and lattice constant of the rare-earth hydride superconducting material in this embodiment are respectively and The shortest HH distance for this material at 181 GPa is It has a superconducting transition temperature of 58K under a high pressure of 181 GPa.

[0113] It should be noted that the inventors conducted a large number of experiments during the research process. The pressure and temperature were not exactly the same in different experiments, but as long as the target pressure was kept between 160 and 185 GPa and the target temperature was kept between 1200 and 1500℃, and a suitable pressure and temperature holding time of 3 to 5 minutes was matched, the above-mentioned rare earth hydride superconducting materials could be obtained.

[0114] Example 3

[0115] This embodiment provides a rare-earth hydride superconducting material and its preparation method. The chemical formula of the rare-earth hydride superconducting material in this embodiment is LuH. 3-m N y Where 3-m is the atomic ratio of H to Lu, 0.001≤m≤1; y is the doping ratio of N to H, 0<y≤30%.

[0116] The overall steps of the preparation method of the rare earth hydride superconducting material in this embodiment are the same as those in Example 2, the difference being:

[0117] Specifically, in the above S1, the rare earth element raw material, the hydrogen source material and the doping element raw material are encapsulated into the high-pressure cavity of the diamond anvil device.

[0118] Specifically, in the above S1, the doping element raw material is potassium azide.

[0119] Specifically, in the above S2, the target pressure is 145 GPa.

[0120] Specifically, in the above S2, the target temperature is 1300℃.

[0121] Specifically, in the above S2, the pressure holding and temperature holding time is 3 minutes.

[0122] The structure of the rare earth hydride superconducting material prepared in the embodiment is tested and analyzed, and the lattice constant is LuH 2.9 Close to, such as Figure 6 The relationship between the superconducting transition temperature of the rare earth hydride superconducting material of the embodiment and the N doping amount is shown in the figure. It is found through resistance test that the superconducting transition temperature gradually increases with the increase of N doping amount near 150 GPa, for example, when the N doping amount is 0.5% to 3%, the superconducting transition temperature increases from 59K to 65K. The nitrogen-doped lutetium hydride provided by the present application has obvious effect in reducing the preparation pressure and improving the superconducting transition temperature, which has important research value for the application of hydrogen-based superconducting material.

[0123] It should be noted that the inventors have carried out a large number of experiments in the research process, and the pressure and temperature in different experimental processes are not completely the same, but as long as the target pressure is 140-150 GPa, the target temperature is 1200-1500℃, and the appropriate pressure holding and temperature holding time is 3-10 minutes, the above rare earth hydride superconducting material can be obtained.

[0124] Embodiment 4

[0125] The embodiment provides a rare earth hydride superconducting material and a preparation method thereof. The chemical formula of the rare earth hydride superconducting material in the embodiment is LuH 3-m C 0.1 . Wherein, 3-m is the atomic ratio of H to Lu, 0.001≤m≤1.

[0126] The preparation method of the rare earth hydride superconducting material of the embodiment has the same overall steps as those of embodiment 2, and the difference lies in that:

[0127] Specifically, in the above S1, the rare earth element raw material, the hydrogen source material and the doping element raw material are encapsulated into the high-pressure cavity of the diamond anvil device.

[0128] Specifically, in the above S1, the doping element raw material is carbon powder.

[0129] Specifically, in the above S2, the target pressure is 155 GPa.

[0130] Specifically, in the above S2, the target temperature is 1200℃.

[0131] Specifically, in the above S2, the pressure holding and temperature holding is 5 minutes.

[0132] The structure of the rare earth hydride superconducting material prepared in the embodiment is tested and analyzed, and the lattice constant is LuH 2.9 Close to, such as Figure 7 As shown in the resistance-temperature curve of the rare earth hydride superconducting material of the embodiment, it is found that the rare earth hydride superconducting material of the embodiment has a superconducting transition temperature of 90K. The carbon-doped lutetium hydride provided by the application has obvious effect in reducing the preparation pressure and improving the superconducting transition temperature, which has important research value for the application of hydrogen-based superconducting materials.

[0133] It should be noted that the inventors have conducted a large number of experiments during the research process, and the pressure and temperature are not completely the same in different experimental processes, but as long as the target pressure is 145-155 GPa, the target temperature is 1200-1500℃, and the appropriate pressure holding and temperature holding time is 3-10 minutes, the above rare earth hydride superconducting material can be obtained.

[0134] Embodiment 5

[0135] The embodiment provides a rare earth hydride superconducting material and a preparation method thereof. The chemical formula of the rare earth hydride superconducting material in the embodiment is LuH 3-m B 0.05 . Wherein, 3-m is the atomic ratio of H to Lu, 0.001≤m≤1.

[0136] The preparation method of the rare earth hydride superconducting material of the embodiment has the same overall steps as those of embodiment 2, and the difference lies in that:

[0137] Specifically, in the above S1, the rare earth element raw material, the hydrogen source material and the doping element raw material are packaged into the high-pressure cavity of the diamond anvil device.

[0138] Specifically, in the above S1, the doping element raw material is boron powder.

[0139] Specifically, in the above S2, the target pressure is 120 GPa.

[0140] Specifically, in the above S2, the target temperature is 1300℃.

[0141] Specifically, in the above S2, the pressure holding and temperature holding is 5 minutes.

[0142] The rare earth hydride superconducting material prepared in the embodiment is subjected to structure test and analysis, and the lattice constant is 4. 12 A, which is consistent with the lattice constant of YH 2.9 The superconducting transition temperature of the rare earth hydride superconducting material of the embodiment is 120 K. The boron-doped lutetium hydride provided by the application has obvious effect in reducing the preparation pressure and increasing the superconducting transition temperature, which has important research value for the application of hydrogen-based superconducting materials.

[0143] It should be noted that the inventors have carried out a large number of experiments in the research process, and the pressure and temperature are not completely the same in different experimental processes, but as long as the target pressure is 110-130 GPa, the target temperature is 1200-1500 ℃, and the appropriate pressure holding and temperature holding time is 3-10 minutes, the above-mentioned rare earth hydride superconducting material can be obtained.

[0144] Embodiment 6

[0145] The embodiment provides a rare earth hydride superconducting material and a preparation method thereof. The chemical formula of the rare earth hydride superconducting material in the embodiment is Y4H 23 .

[0146] The preparation method of the rare earth hydride superconducting material of the embodiment has the same overall steps as those of embodiment 1, and the difference lies in that:

[0147] Specifically, in the above S1, the hydrogen source material is ammonia borane, which is in the form of powder and is placed in the high-pressure cavity.

[0148] Specifically, in the above S1, the metal material is high-purity yttrium, which is deposited on the upper surface of the diamond anvil by a magnetron sputtering method, and the thickness of the yttrium is 0.1-2 microns.

[0149] Specifically, in the above S1, the packaging pressure is 1 GPa.

[0150] Specifically, in the above S2, the target pressure is 120 GPa.

[0151] Specifically, in the above S2, the target temperature is 1600 ℃.

[0152] Specifically, in the above S2, the pressure holding and temperature holding time is 6 minutes.

[0153] Specifically, the rare earth hydride superconducting material prepared in the embodiment is subjected to structure test and analysis, and it is confirmed that the chemical formula of the obtained rare earth hydride superconducting material is Y4H 23 ; the magnetization rate test is carried out under high-pressure conditions, and as shown in FIG. 2, the rare earth hydride superconducting material of the embodiment has a superconducting transition temperature of 76 K. Figure 8 ​

[0154] It should be noted that the inventors have carried out a large number of experiments in the research process, and the pressure and temperature are not completely the same in different experimental processes, but as long as the target pressure is 120-150 GPa, the target temperature is 1500-1800 ℃, and the appropriate pressure and temperature holding time of 5-10 minutes is matched, the above rare earth hydride superconducting material can be obtained.

[0155] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A rare earth hydride superconductor material, characterized by, The rare earth hydride superconductor material has a chemical formula of Lu4H 23 ; The raw material is encapsulated in the high-pressure cavity at a pressure of 0.5-10 GPa during the preparation of the rare earth hydride superconducting material. The rare earth hydride superconducting material has a superconducting transition temperature of 55 K or above.

2. The rare earth hydride superconductor material of claim 1, wherein, The rare earth hydride superconducting material further comprises a non-metallic doping element, The doping element has a doping atomic ratio of H of y, and 0 3. The rare earth hydride superconducting material of claim 2, wherein The rare earth hydride superconducting material has a superconducting transition temperature of 55 K or above.

4. A method of producing a rare earth hydride superconductor material as claimed in any one of claims 1 to 3, characterized by, The method comprises the following steps: S1, encapsulating hydrogen source material and rare earth elements or hydrogen source material, rare earth elements and doping elements into a high-pressure cavity; S2, pressurizing the raw materials in the high-pressure cavity to a target pressure, then heating to a target temperature, and maintaining the pressure and temperature to prepare the rare earth hydride superconducting material; the target pressure is 100-220 GPa, and the target temperature is 50-2000℃; The rare earth hydride superconducting material has a superconducting transition temperature of 55 K or above.

5. The preparation method according to claim 4, characterized in that, In S1, the hydrogen source material and the doping element raw material exist in gaseous or solid state.

6. The preparation method according to claim 5, characterized in that, In S1 and S2, when the hydrogen source material and the doping element raw material exist in gaseous form, the target temperature is lower than when the hydrogen source material and the doping element raw material exist in solid form.

7. The preparation method according to claim 4, characterized in that, The S1 further comprises completing the preparation work of the high-pressure device, and the preparation work comprises: S01. Select the matching gasket according to the anvil area of the high-pressure device, and pre-press to make a pressure mark at the center of the gasket, or select a suitable sample cavity according to the type of the high-pressure device; S02. Then, punch a hole at the center of the pressure mark of the gasket, which is the high-pressure cavity for sample encapsulation and reaction; S03. Then, fix the gasket at the pressure mark position of the lower anvil surface of the high-pressure device; S04. Fix the relative positions of the upper anvil, gasket and lower anvil, wherein a certain distance is maintained between the upper anvil and the lower anvil for the encapsulation of gaseous raw materials.

8. The preparation method according to claim 7, characterized in that, The high-pressure device is selected from a multi-face top press, a two-face top press or a ring press.

9. The preparation method according to claim 4, characterized in that, In S1, the encapsulation pressure is 0.5-10 GPa.

10. The production method according to any one of claims 4 to 9, characterized in that, In S1, the rare earth element raw material is placed in the high-pressure cavity in the form of a thin film.

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