Rare earth magnetic single crystal material as well as preparation method and application thereof

Abstract

The invention relates to a rare earth magnetic single crystal material and a preparation method and application thereof, the chemical formula of the rare earth magnetic single crystal material is HoAuSi2, the rare earth magnetic single crystal material has a hexagonal crystal system structure, the lattice constants of the rare earth magnetic single crystal material are a = b = 4.09 and c = 4.03, the electric transport shows metallic property, and the Curie temperature of the rare earth magnetic single crystal material is 8K. The rare earth magnetic single crystal material HoAuSi2 provided by the invention has a unique hexagonal system structure, and shows the Curie temperature of 8K and the resistance characteristic of metal behavior at low temperature; and a new possibility and a new research direction are provided for further exploring potential application of a novel functional material in the frontier fields of quantum calculation, low-temperature electronics, spintronics, novel magnetic sensors and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a rare earth magnetic single crystal material and a preparation method and application thereof. Background Art

[0002] In the field of modern materials science, the exploration and development of new functional materials has always been a research hotspot, aiming to meet the increasingly stringent requirements of the growing high-tech industry for material performance.

[0003] Rare earth metals and their compounds often exhibit rich and diverse and eye-catching physical properties due to their unique 4f electronic structure. They have potential application value in many fields such as magnetism, electricity, and optics, and therefore have attracted widespread attention. Among them, gold (Au), as a precious metal with excellent conductivity and chemical stability, has an important application basis in electronic devices and other aspects. Silicon (Si) is the cornerstone of the semiconductor industry. Its electrical properties and controllable crystal structure make it a key element in building various electronic and optoelectronic devices.

[0004] In recent years, researchers have been committed to combining rare earth elements with other metals and metalloid elements, hoping to develop material systems with novel properties to fill the gaps in certain specific properties of existing materials and expand the scope of application of materials. However, existing material systems still have limitations in the coordinated regulation of low-temperature physical properties and crystal structures, making it difficult to simultaneously meet the needs of some emerging technologies for materials with special electrical and magnetic properties. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a rare earth magnetic single crystal material and a preparation method and application thereof. The rare earth magnetic single crystal material has a hexagonal crystal structure, exhibits metallic properties in electrical transport, has a Curie temperature of 8K, and has good conductivity and stability at low temperatures, which provides new possibilities and research directions for further exploring the potential applications of new functional materials in cutting-edge fields such as quantum computing, low-temperature electronics, spin electronics, and new magnetic sensors.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a rare earth magnetic single crystal material, whose chemical formula is HoAuSi2, which has a hexagonal crystal structure, whose lattice constants are a=b=4.09Å, c=4.03Å, whose electrical transport exhibits metallic properties, and whose Curie temperature is 8K.

[0007] The rare earth magnetic single crystal material HoAuSi2 provided by the present invention has a unique hexagonal crystal structure, and exhibits a Curie temperature of 8K and a resistance characteristic of metallic behavior at low temperatures. The Curie temperature of 8K and the metallic resistance behavior of HoAuSi2 single crystal make it have good conductivity and stability at low temperatures, and can be used to manufacture electrodes, connecting wires and other components in low-temperature quantum devices to ensure the efficient operation of quantum computing systems in low-temperature environments; based on its magnetic and resistance characteristics that change with temperature, it can also be used to make low-temperature sensors for detecting physical quantities such as temperature changes or magnetic field changes in extremely low temperature environments; the Ho ions in HoAuSi2 may cause the material to have a strongly correlated electronic effect, which can be used to study physical phenomena in strongly correlated electronic systems, such as the interaction between the spin, charge and orbital freedom of electrons; therefore, the discovery of HoAuSi2 single crystals provides new possibilities and research directions for further exploring the potential applications of new functional materials in frontier fields such as quantum computing, low-temperature electronics, spin electronics and new magnetic sensors.

[0008] As a further improvement of the above solution of the present invention, the longitudinal resistivity of the rare earth magnetic single crystal material at room temperature is 1.53×10 2 μΩcm.

[0009] As a further improvement of the above solution of the present invention, the naturally grown surface of the rare earth magnetic single crystal material is a (010) crystal plane.

[0010] The present invention also provides a method for preparing the rare earth magnetic single crystal material as described above, which comprises the following steps: mixing the self-fluxing agent Sn powder with the Ho powder, Au powder and Si powder, vacuum sealing, calcining, cooling to a predetermined temperature and immediately centrifuging to obtain the rare earth magnetic single crystal material.

[0011] As a further improvement of the above solution of the present invention, the molar ratio of Ho powder, Au powder, Si powder and Sn powder is 1:1:1-2:10-15.

[0012] As a further improvement of the above scheme of the present invention, the process of using Sn powder as a self-flux and mixing it with Ho powder, Au powder and Si powder and then vacuum sealing it includes the following steps: in an argon-protected glove box, placing the Ho powder, Au powder, Si powder and Sn powder into a pretreated alumina crucible, and then placing the alumina crucible in a quartz tube and vacuum sealing it with an oxyhydrogen flame.

[0013] As a further improvement of the above scheme of the present invention, the pretreatment method of the alumina crucible is: rinse the alumina crucible with deionized water, then place the alumina crucible in deionized water for ultrasonic cleaning for 30-35 minutes, then place it at 1000-1050°C for 10-15 hours, and then take it out from the furnace for cooling.

[0014] As a further improvement of the above solution of the present invention, the calcination is carried out at 1050-1100° C. for 10-15 hours.

[0015] As a further improvement of the above scheme of the present invention, the cooling speed is 1-1.5°C / h, the predetermined temperature is 850-900°C; and / or the centrifugal speed is 1500-2000r / min, and the centrifugal time is 5-10min.

[0016] The present invention also provides an application of the rare earth magnetic single crystal material as described above in low-temperature quantum devices, magnetic sensors, and strongly correlated materials.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The rare earth magnetic single crystal material HoAuSi2 provided by the present invention has a unique hexagonal crystal structure, exhibits a Curie temperature of 8K and a resistance characteristic of metallic behavior at low temperatures. The Curie temperature of HoAuSi2 single crystal of 8K and the metallic resistance behavior make it have good conductivity and stability at low temperatures, and can be used to manufacture electrodes, connecting wires and other components in low-temperature quantum devices, ensuring the efficient operation of quantum computing systems in low-temperature environments; the resistivity of HoAuSi2 single crystal at room temperature (T=300K) is 1.53×10 2 μΩcm, as the temperature decreases, the resistivity also decreases. Based on the magnetic and resistive properties of HoAuSi2 single crystals that change with temperature, it can also be used to make low-temperature sensors to detect physical quantities such as temperature changes or magnetic field changes in extremely low temperature environments; the Ho ions in HoAuSi2 can cause the material to have a strongly correlated electron effect, which can be used to study physical phenomena in strongly correlated electron systems, such as the interaction between the electron's spin, charge and orbital freedom; therefore, the discovery of HoAuSi2 single crystals provides new possibilities and research directions for further exploring the potential applications of new functional materials in cutting-edge fields such as quantum computing, cryogenic electronics, spin electronics and new magnetic sensors.

[0018] 2. The present invention uses Sn as a flux, and the raw material and flux powder are placed in an alumina crucible and vacuum-sealed in a quartz tube. After high-temperature melting, the temperature is slowly lowered to precipitate HoAuSi2 single crystals, and then the flux is removed by centrifugation at a specific temperature to obtain HoAuSi2 single crystals. The self-fluxing method does not introduce other impurities, can ensure the uniformity of the grown crystals, and has simple equipment and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A physical picture of the HoAuSi2 single crystal prepared in the embodiment of the present invention; Figure 2XRD patterns of HoAuSi2 single crystal and powder prepared in the embodiments of the present invention; Figure 3 A schematic diagram of the structure of a HoAuSi2 single crystal prepared in an embodiment of the present invention; Figure 4 The SEM morphology and element distribution diagram of the HoAuSi2 single crystal prepared in the embodiment of the present invention; Figure 5 The χ-T (a) and MH (b) curves of the magnetic field of the HoAuSi2 single crystal prepared in the embodiment of the present invention along different directions; Figure 6 The longitudinal resistivity of the HoAuSi2 single crystal prepared in the embodiment of the present invention is ρ xx Temperature variation diagram. DETAILED DESCRIPTION

[0020] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0022] This embodiment provides a rare earth magnetic single crystal material, which is grown by a flux method, and specifically includes the following steps: S1. Pretreatment of alumina crucible: clean the alumina crucible with deionized water, then place the cleaned alumina crucible in a beaker filled with deionized water and ultrasonically clean it for 30 minutes to remove impurities attached to the wall of the alumina crucible; finally, place the alumina crucible in a high-temperature box furnace and dry it at 1000°C for 10 hours to remove moisture in the crucible to obtain a pretreated alumina crucible.

[0023] S2. Raw material weighing and packaging: In a glove box protected by high-purity argon gas (water content <0.1 ppm, oxygen content <0.1 ppm), weigh high-purity Ho powder (purity: 99.9%), Au powder (purity: 99.99%), Si powder (purity: 99.9%) and flux Sn powder (purity: 99.9%) in a molar ratio of 1:1:2:15 and put them into a pretreated alumina crucible; put the loaded alumina crucible into a quartz tube, and use a vacuum pump to evacuate the quartz tube to 10 -3 After Pa, it is sealed by hydrogen-oxygen flame.

[0024] S3. Single crystal growth: Place the sealed quartz tube in a high-temperature box furnace, heat it to 1100℃ at 100℃ / h and keep it warm for 10h to fully melt the raw materials and mix them evenly; then slowly cool it down to 900℃ at 1℃ / h. During this process, the crystals spontaneously nucleate and crystallize from the saturated melt and gradually grow.

[0025] S4. Crystal separation: At 900°C, the quartz tube was quickly taken out from the high-temperature box furnace and placed upside down in a centrifuge. The crystal was separated from the flux by high-speed centrifugation (speed 1500 r / min, centrifugation time 10 min) to obtain a HoAuSi2 single crystal sample.

[0026] Figure 1 The actual picture of the HoAuSi2 single crystal obtained in this embodiment is as follows: Figure 1 It can be seen that the surface of the HoAuSi2 single crystal prepared in this embodiment presents a very bright metallic luster.

[0027] Using X-ray diffractometer (XRD, PANalytical X'pert, Cu- K α1 , λ=0.15406 nm) X-ray diffraction was performed on the HoAuSi2 single crystal and its powder obtained in this embodiment, and the following results were obtained: Figure 2 The XRD patterns of the single crystal and powder shown are Figure 2 It can be seen that the naturally grown surface of the rare earth magnetic single crystal material prepared in this embodiment is the (010) crystal plane; the XRD spectrum of the HoAuSi2 powder prepared in this embodiment is refined to obtain: a=b=4.09Å, c=4.03Å, α=β=90°, γ=120°.

[0028] According to the XRD pattern analysis, Figure 3 The crystal structure of the rare earth magnetic single crystal material prepared in this embodiment is shown, in which Si atoms form hexagonal close-packed stacking, Ho atoms and Au atoms occupy octahedral positions respectively, and the space group is P63 / mmc.

[0029] The chemical composition and elemental distribution of the HoAuSi2 single crystal prepared in this embodiment were characterized by using a scanning electron microscope (SEM) and its accessory energy dispersive spectrometer (EDS), and the following results were obtained: Figure 4 The SEM morphology and element distribution shown in Figure 4 It can be seen that the surface of the crystal obtained in this embodiment is smooth and flat without obvious defects, and the three elements Ho, Au and Si are evenly distributed in the single crystal.

[0030] The magnetic properties of the HoAuSi2 single crystal prepared in this embodiment were tested by superconducting quantum interference instrument (MPMS-5T, 1.9K≤T≤400K, 0≤H≤5T). The test results are as follows: Figure 5 shown; from Figure 5 (a) It can be seen that the magnetic field along the c-axis and ab-plane shows that: as the temperature T decreases, the magnetic susceptibility χ gradually increases. When the temperature is below a certain level, the ZFC and FC curves do not overlap, showing glass behavior; the rate of change of the magnetic susceptibility χ along the c-axis and ab-plane with temperature T peaks at 8K, so the Curie temperature T C =8K. Figure 5 As can be seen from Figure (b), when T=3K, the MH curve exhibits soft magnetic behavior, and the easy magnetization axis is along the c-axis.

[0031] The electrical transport performance of the HoAuSi2 single crystal prepared in this embodiment was tested by means of a low temperature physical property measurement system (PPMS-9T, 1.8K≤T≤400K, 0≤H≤9T): the electrode leads were made by a four-lead method, and the electrical transport of the rare earth magnetic single crystal material was measured to obtain the following Figure 6 The longitudinal resistivity ρ shown xx Temperature variation diagram, from Figure 6 It can be seen that at room temperature (T = 300K), the longitudinal resistivity of rare earth magnetic single crystal material is 1.53×10 2 μΩcm. As the temperature decreases, the resistivity also decreases, showing metallic behavior. The RRR value is about 1.32, and the turning point at T=8K corresponds to the magnetic phase transition.

[0032] According to the above results, it can be explained that the HoAuSi2 single crystal prepared in this application has a unique hexagonal crystal structure, and exhibits a Curie temperature of 8K and a resistance characteristic of metallic behavior at low temperatures. The Curie temperature of 8K and the metallic resistance behavior of the HoAuSi2 single crystal make it have good conductivity and stability at low temperatures, and can be used to manufacture electrodes, connecting wires and other components in low-temperature quantum devices to ensure the efficient operation of quantum computing systems in low-temperature environments; based on its magnetic and resistance properties that change with temperature, it can also be used to make low-temperature sensors for detecting physical quantities such as temperature changes or magnetic field changes in extremely low temperature environments; the Ho ions in HoAuSi2 can cause the material to have a strongly correlated electronic effect, which can be used to study physical phenomena in strongly correlated electronic systems, such as the interaction between the spin, charge and orbital freedom of electrons; therefore, the discovery of the HoAuSi2 single crystal provides new possibilities and research directions for further exploring the potential applications of new functional materials in frontier fields such as quantum computing, low-temperature electronics, spin electronics and new magnetic sensors.

[0033] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A rare earth magnetic single crystal material, characterized in that: Its chemical formula is HoAuSi2, it has a hexagonal crystal structure, its lattice constants are a=b=4.09Å, c=4.03Å, its electrical transport exhibits metallic properties, and its Curie temperature is 8K.

2. The rare earth magnetic single crystal material according to claim 1, characterized in that: The rare earth magnetic single crystal material has a longitudinal resistivity of 1.53×10 2 μΩcm.

3. The rare earth magnetic single crystal material according to claim 1, characterized in that: The naturally grown surface of the rare earth magnetic single crystal material is a (010) crystal plane.

4. A method for preparing the rare earth magnetic single crystal material according to any one of claims 1 to 3, characterized in that: It includes the following steps: After the self-fluxing agent Sn powder is mixed with Ho powder, Au powder and Si powder, the mixture is vacuum sealed, calcined, cooled to a predetermined temperature and then centrifuged immediately to obtain a rare earth magnetic single crystal material.

5. The method for preparing rare earth magnetic single crystal material according to claim 4, characterized in that: The molar ratio of Ho powder, Au powder, Si powder and Sn powder is 1:1:1-2:10-15.

6. The method for preparing a rare earth magnetic single crystal material according to claim 4, characterized in that: The method of using Sn powder as a self-flux and mixing it with Ho powder, Au powder and Si powder and then vacuum sealing it comprises the following steps: in an argon-protected glove box, placing the Ho powder, Au powder, Si powder and Sn powder into a pretreated alumina crucible, then placing the alumina crucible in a quartz tube, and vacuum sealing it with an oxyhydrogen flame.

7. The method for preparing a rare earth magnetic single crystal material according to claim 6, characterized in that: The pretreatment method of the alumina crucible is: rinse the alumina crucible with deionized water, then place the alumina crucible in deionized water for ultrasonic cleaning for 30-35 minutes, then place it at 1000-1050° C. for 10-15 hours, and then take it out from the furnace for cooling.

8. The method for preparing a rare earth magnetic single crystal material according to claim 4, characterized in that: The calcination is carried out at 1050-1100° C. for 10-15 hours.

9. The method for preparing a rare earth magnetic single crystal material according to claim 4, characterized in that: The cooling speed is 1-1.5°C / h, and the predetermined temperature is 850-900°C; and / or, the centrifugal speed is 1500-2000r / min, and the centrifugal time is 5-10min.

10. Use of the rare earth magnetic single crystal material according to any one of claims 1 to 3 in low-temperature quantum devices, magnetic sensors, and strongly correlated materials.

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