A Co-As-Sn single crystal alloy, its preparation method and application

Abstract

This invention relates to the field of magnetic sensor technology, and more particularly to a Co-As-Sn single-crystal alloy, its preparation method, and its applications. This invention prepares a Co-As-Sn single-crystal alloy by doping Co and As with Sn. Sn doping alters the alloy's band structure and Berry curvature, thereby affecting its magnetoresistive behavior. This allows the prepared Co-As-Sn single-crystal alloy to function normally as a linear magnetoresistive material at low temperatures, with a wider operating temperature range, thus better meeting the needs of magnetic sensors and enabling them to play a more important role in various fields. This invention solves the problem of narrow temperature ranges in existing linear magnetoresistive materials, which cannot meet the needs of magnetic sensors.

Description

Technical Field

[0001] This invention relates to the field of magnetic sensor technology, specifically to a Co-As-Sn single crystal alloy, its preparation method, and its application. Background Technology

[0002] Magnetoresistive effect is a physical phenomenon specifically referring to the change in resistance of certain metals or semiconductors with the application of an external magnetic field. The magnetoresistive effect mainly arises from the deflection of charge carriers (such as electrons or holes) in a magnetic field due to the Lorentz force. This deflection increases the effective path length of the charge carriers within the conductor or semiconductor, thus causing a change in resistance. Specifically, when a magnetic field acts on a conductor or semiconductor, the charge carriers experience a Lorentz force, causing their trajectories to deflect, thereby increasing the scattering opportunities of the charge carriers in the material and leading to increased resistance. It has wide applications and is extensively studied in various fields such as materials science, electronics, and magnetism. In materials science, the magnetoresistive effect can reflect the magnetic state of a material, such as ferromagnetism and antiferromagnetism. By measuring the magnetoresistive effect, we can understand the magnetization curve, coercivity, and other magnetic parameters of the material. Furthermore, it can indirectly provide information about the material's crystal structure and defect distribution, serving as an important indicator for evaluating material performance.

[0003] Because different magnetic materials exhibit varying magnetoresistance effects under magnetic fields, this helps in distinguishing and identifying various magnetic materials. For example, the magnetoresistance of certain metals or semiconductors generally increases quadratically with the magnetic field, saturating in high-field regions. Their magnetoresistance then changes linearly with the magnetic field, exhibiting a significant magnetoresistance effect; these are linear resistive materials. By testing the magnetoresistance of linear resistive materials, the magnitude of the applied magnetic field can be determined. Linear magnetoresistance materials have extremely wide applications and enormous development potential in computer hard drive read heads, magnetic random access memory (MRAM), and magnetic sensors.

[0004] However, the known temperature range of linear magnetoresistive materials is relatively narrow, while magnetic sensors need to operate under varying temperature conditions. If the temperature range of the linear magnetoresistive material is too narrow, the sensor's performance may vary significantly under different temperature conditions, leading to inaccurate measurement results or even malfunction. This limits the application of linear magnetoresistive materials in magnetic sensors. Therefore, finding a linear magnetoresistive material with strong magnetic response and a wide temperature range has become an urgent problem to be solved by the physics and electronic information science and technology communities. Summary of the Invention

[0005] To address the problem that existing linear magnetoresistive materials have a narrow temperature range, which cannot meet the requirements of magnetic sensors, this invention provides a Co-As-Sn single crystal alloy, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] This invention provides a Co-As-Sn single crystal alloy comprising Co, As and Sn, wherein the molar ratio of Co, As and Sn is (0.95-1.05):(0.75-0.85):(0.33-0.43).

[0008] Optionally, it includes:

[0009] Co powder, As powder, and Sn granules are mixed to obtain a mixture;

[0010] The mixture is heated and melted to obtain a pre-formulated alloy melt;

[0011] The pre-formed alloy melt is cooled and crystallized, and excess Sn is separated to obtain a Co-As-Sn single crystal alloy.

[0012] Optionally, the molar ratio of Co powder, As powder and Sn particles is (0.95-1.05):(0.75-0.85):(9-11).

[0013] Optionally, the heating and melting temperature is 800℃~850℃, and the holding time is 48~60h.

[0014] Optionally, the heating and melting time is 8 to 8.5 hours.

[0015] Optionally, the cooling rate of the cooling crystallization is 1–3 °C / h.

[0016] Optionally, the method for cooling and crystallizing the pre-formed alloy melt and separating the excess Sn to obtain a Co-As-Sn single crystal alloy is as follows:

[0017] The pre-formed alloy melt was cooled to 500℃~550℃ at a cooling rate of 1~3℃ / h to separate the excess Sn and obtain Co-As-Sn single crystal alloy melt.

[0018] Co-As-Sn single crystal alloy melt is cooled to room temperature in air to obtain Co-As-Sn single crystal alloy.

[0019] Optionally, both the heating and melting and the cooling and crystallization are carried out under vacuum conditions.

[0020] This invention provides a Co-As-Sn single crystal alloy, prepared using the method described above, wherein the operating temperature range of the Co-As-Sn single crystal alloy is 2K to 300K.

[0021] The above-mentioned application of Co-As-Sn single crystal alloys in magnetic sensors.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention discloses a Co-As-Sn single-crystal alloy, comprising Co, As, and Sn, wherein the molar ratio of Co, As, and Sn is (0.95–1.05):(0.75–0.85):(0.33–0.43). Co is an important magnetic element with excellent magnetic and electrical properties. In the Co-As-Sn single-crystal alloy, it can improve the alloy's hardness and strength while maintaining good plasticity and toughness. As can enhance the corrosion resistance and thermal stability of the Co-As-Sn single-crystal alloy, enabling it to maintain stable performance and extend its service life under harsh environments. Sn, as a dopant in the magnetic material composed of Co and As, can improve the band structure and Berry curvature of the Co-As-Sn single-crystal alloy. Changes in the band structure of a Co-As-Sn single-crystal alloy affect its magnetoresistance behavior. Band structure is a crucial way to describe the energy state of electrons in a solid, determining their motion and distribution. Berry curvature, a geometric property describing electron motion, can influence the orbital and spin motion of electrons, thus affecting the alloy's magnetoresistance behavior. By doping with Sn, the band structure of the alloy changes, affecting electron transport characteristics. This optimization allows the alloy to maintain high magnetoresistance and stable performance at low temperatures, enabling Co-As-Sn single-crystal alloys to function normally as linear magnetoresistance materials at low temperatures. This results in a wider operating temperature range and stronger overall performance, providing a new direction for the improvement and optimization of magnetic sensors.

[0024] This invention also provides a method for preparing a Co-As-Sn single-crystal alloy as described above. This method involves mixing Co powder, As powder, and Sn particles to obtain a mixture; then, heating and melting the mixture to obtain a pre-formed alloy melt; finally, cooling and crystallizing the pre-formed alloy melt and separating excess Sn to obtain the Co-As-Sn single-crystal alloy. The mixing of Co powder, As powder, and Sn particles ensures a uniform distribution of various elements in the Co-As-Sn single-crystal alloy. The mixing process is simple, easy to implement, and easy to control, laying a good foundation for subsequent steps. The heating and melting process ensures that the various elements in the mixture react fully, forming a uniform pre-formed alloy melt, thus optimizing the microstructure and properties of the Co-As-Sn single-crystal alloy. Cooling and crystallizing the pre-formed alloy melt allows the elements in the melt to arrange themselves in a specific order and manner, forming a single-crystal structure. By separating excess Sn, the composition ratio of the Co-As-Sn single-crystal alloy can be ensured to meet the design requirements. This method is simple to operate and highly controllable. Moreover, the prepared Co-As-Sn single crystal alloy is a linear magnetoresistive material with a wider operating temperature range, providing new material options and technical support for the development of related fields.

[0025] The molar ratio of Co powder, As powder, and Sn particles is (0.95–1.05):(0.75–0.85):(9–11). The excessive addition of Sn particles in the raw materials can better ensure the effective doping of Sn, so that the elements in the final Co-As-Sn single crystal alloy are within the design range, ensuring that the Co-As-Sn single crystal alloy can meet the working requirements of a wider temperature range. At the same time, it helps to optimize the microstructure and properties of the alloy, giving it better mechanical, magnetic, and electrical properties.

[0026] The heating and melting temperature is 800℃~850℃, and the holding time is 48~60h. Heating and melting within the temperature range of 800℃~850℃ ensures that Co powder, As powder, and Sn particles react fully and promotes their uniform distribution in the melt. This helps reduce component segregation and microstructure inhomogeneity in the alloy, improving the overall performance of the alloy. Holding for 48~60h provides sufficient time for grain growth, allowing the grains to gradually grow and become more uniform, thereby optimizing the microstructure of the alloy.

[0027] The heating and melting time is 8 to 8.5 hours. Under this heating condition, the mixture can be heated evenly during the heating process, reducing the thermal stress generated during heating, reducing internal defects of the Co-As-Sn single crystal alloy, and ensuring the quality of the Co-As-Sn single crystal alloy.

[0028] The cooling rate of the cooling crystallization process is 1-3℃ / h, which ensures that the alloy melt crystallizes uniformly during the cooling process, so that the elements in the alloy are arranged in a specific order and manner to form an ordered single crystal structure.

[0029] Excess Sn was separated by cooling the pre-prepared alloy melt to 500℃~550℃ at a cooling rate of 1~3℃ / h, resulting in a Co-As-Sn single-crystal alloy melt. Sn separation was performed within this temperature range because Sn has low solubility at this temperature, making it easier for it to precipitate from the alloy melt. Separating excess Sn allows for further purification of the Co-As-Sn single-crystal alloy, improving its single-crystal quality.

[0030] Both the heating and melting process and the cooling and crystallization process are carried out under vacuum conditions. Heating and melting under vacuum conditions can effectively reduce the contact between the alloy and gases such as oxygen and nitrogen in the air, thereby avoiding oxidation and contamination, helping to maintain the purity of the alloy, and improving the performance of the final product. At the same time, the vacuum environment can reduce heat conduction and convection, making the heat more concentrated in the alloy melt and improving heating efficiency. Cooling and crystallization under vacuum conditions can reduce the interference of the external environment on the crystallization process, allowing the alloy to arrange itself in a specific order and manner to form an ordered single crystal structure, which helps to improve the performance and stability of the single crystal alloy.

[0031] This invention provides a Co-As-Sn single crystal alloy, prepared using the method described above. Testing shows that the Co-As-Sn single crystal alloy has a working temperature range of 2K to 300K, exhibiting a wider working temperature range. This allows it to maintain high magnetic sensitivity and stability, improve the anti-interference capability of magnetic sensors, and thus meet the accuracy requirements of magnetic sensors under different temperature conditions.

[0032] The above-mentioned application of Co-As-Sn single-crystal alloys in magnetic sensors illustrates this. Co-As-Sn single-crystal alloys possess a wide operating temperature range and maintain stable magnetic properties under extreme temperature conditions, enabling magnetic sensors to maintain accurate measurements even in high or low temperature environments, thus improving their stability and reliability. Furthermore, due to the unique magnetic and electronic structure of Co-As-Sn single-crystal alloys, they exhibit higher magnetic sensitivity when used as the sensing element of magnetic sensors. High sensitivity means that the sensor can respond more accurately to changes in the magnetic field, thereby improving measurement accuracy and allowing magnetic sensors to play an important role in more fields. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating the preparation process of a Co-As-Sn single crystal alloy according to the present invention.

[0034] Figure 2This is a physical image of the Co-As-Sn single crystal alloy prepared in Example 1 of the present invention.

[0035] Figure 3 The image shows the energy-dispersive X-ray spectra of the Co-As-Sn single-crystal alloy prepared in Example 1 of this invention.

[0036] Figure 4 The graph shows the relationship between magnetoresistance and magnetic field at different temperatures for the Co-As-Sn single crystal alloy prepared in Example 1 of this invention. Detailed Implementation

[0037] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0038] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0039] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0040] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0041] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0042] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0043] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0044] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0045] This invention discloses a Co-As-Sn single crystal alloy comprising Co, As and Sn, wherein the molar ratio of Co, As and Sn is (0.95-1.05):(0.75-0.85):(0.33-0.43), preferably 1:0.8:0.38.

[0046] See Figure 1 This invention provides a method for preparing the Co-As-Sn single crystal alloy as described above, comprising:

[0047] S1: Mix Co powder, As powder, and Sn granules to obtain a mixture, specifically:

[0048] Co powder with a purity of 2N8 (99.8%), As powder with a purity of 5N (99.999%), and Sn particles with a purity of 5N (99.999%) are mixed uniformly in a protective atmosphere at a molar ratio of (0.95–1.05):(0.75–0.85):(9–11); preferably, the protective atmosphere is argon or helium, more preferably argon; the molar ratio of 2N8 (99.8%) Co powder, As powder with a purity of 5N (99.999%), and Sn particles with a purity of 5N (99.999%) is preferably 1:0.8:10;

[0049] S2: The mixture is heated and melted to obtain a pre-formed alloy melt, specifically:

[0050] The mixture was heated to 800℃~850℃ under vacuum conditions for 8~8.5h, and held at that temperature for 48~60h to obtain a pre-made alloy melt.

[0051] S3: The pre-formed alloy melt is cooled and crystallized, and excess Sn is separated to obtain a Co-As-Sn single crystal alloy, specifically:

[0052] Under vacuum conditions, the pre-formed alloy melt is cooled to 500℃~550℃ at a cooling rate of 1~3℃ / h to separate the excess Sn and obtain Co-As-Sn single crystal alloy melt; preferably, the excess Sn is separated by centrifugation.

[0053] Co-As-Sn single crystal alloy melt is cooled to room temperature in air to obtain Co-As-Sn single crystal alloy.

[0054] This invention provides a Co-As-Sn single crystal alloy, prepared using the above method. Testing shows that the Co-As-Sn single crystal alloy has a working temperature range of 2K to 300K, exhibiting a wider working temperature range. This allows it to maintain high magnetic sensitivity and stability, improve the anti-interference capability of magnetic sensors, and thus meet the accuracy requirements of magnetic sensors under different temperature conditions.

[0055] The above-mentioned application of Co-As-Sn single-crystal alloys in magnetic sensors illustrates this. Co-As-Sn single-crystal alloys possess a wide operating temperature range and maintain stable magnetic properties under extreme temperature conditions, enabling magnetic sensors to maintain accurate measurements even in high or low temperature environments, thus improving their stability and reliability. Furthermore, due to the unique magnetic and electronic structure of Co-As-Sn single-crystal alloys, they exhibit higher magnetic sensitivity when used as the sensing element of magnetic sensors. High sensitivity means that the sensor can respond more accurately to changes in the magnetic field, thereby improving measurement accuracy and allowing magnetic sensors to play an important role in more fields.

[0056] Example 1

[0057] In an argon-filled glove box, Co powder (purity 2N8, purchased from Alfa), As powder (purity 5N, purchased from Aladdin), and Sn granules (purity 5N, purchased from Sinopharm Reagent Network) were mixed, and the mixture was placed in an alumina crucible; wherein the molar ratio of Co powder, As powder, and Sn granules was 1:0.8:10.

[0058] An alumina crucible is placed in a quartz tube and stuffed with quartz wool. Argon gas is extracted from the quartz tube using a mechanical pump-molecular pump assembly, and the quartz tube is then sealed. The sealed quartz tube is placed in a box furnace for heating, and the temperature is raised from room temperature to 800°C over 8 hours. The temperature is then maintained at 800°C for 48 hours to ensure that the raw materials are completely melted and to obtain a pre-made alloy melt.

[0059] The pre-formed alloy melt was cooled and crystallized at a rate of 2℃ / h, allowing the sample to precipitate crystals during this process. When the temperature was lowered to 500℃, the excess Sn was separated by placing the inverted quartz tube in a centrifuge. The sample was then cooled to room temperature in air to obtain a Co-As-Sn single-crystal alloy, as shown in the image. Figure 2The image shows an optical photograph of a typical Sn-doped CoAs single crystal, with each grid cell being 1 mm in length. The image also shows that the sample has a regular cuboid morphology, allowing it to be tested directly without any processing.

[0060] See Figure 3 Energy dispersive X-ray spectroscopy was performed on the Co-As-Sn single crystal alloy prepared in Example 1. It can be seen that the molar ratio of Co, As and Sn in the Co-As-Sn single crystal alloy is 1:0.8:0.38.

[0061] Single-crystal analysis was performed on the Co-As-Sn single-crystal alloy prepared in Example 1. The results are shown in the table below:

[0062]

[0063] The analysis results show that the Co-As-Sn single crystal alloy belongs to the hexagonal crystal system with space group P63 / mmc (No. 194) and lattice parameters: a = 3.5929 Å; b = 3.5929 Å; c = 5.2482 Å. It is a Sn-doped phase of CoAs single crystal (P63 / mmc; No. 194), in which some of the As sites are replaced by Sn.

[0064] See Figure 4 The magnetic properties of the Co-As-Sn single crystal alloy prepared in Example 1 were tested. It can be seen that the Co-As-Sn single crystal alloy, as a linear magnetoresistive material, exhibits a linear increase in magnetoresistive resistance with the increase of magnetic field strength, and can still work normally at a low temperature of 2K, showing a wide temperature effect.

[0065] The Co-As-Sn single crystal alloy prepared in Example 1 was immersed in an aqueous solution of hydrochloric acid with a concentration of 10% to 20% for more than 72 hours. After immersion, there were no cracks or pits on the surface of the Co-As-Sn single crystal alloy, indicating that the Co-As-Sn single crystal alloy can respond normally to changes in external magnetic field under acidic conditions without being corroded.

[0066] Example 2

[0067] In an argon-filled glove box, Co powder (purity 2N8, purchased from Alfa), As powder (purity 5N, purchased from Aladdin), and Sn granules (purity 5N, purchased from Sinopharm Reagent Network) were mixed, and the mixture was placed in an alumina crucible; wherein the molar ratio of Co powder, As powder, and Sn granules was 0.95:0.75:9.

[0068] An alumina crucible is placed in a quartz tube and stuffed with quartz wool. Argon gas is extracted from the quartz tube using a mechanical pump-molecular pump assembly, and the quartz tube is then sealed. The sealed quartz tube is placed in a box furnace for heating, and the temperature is raised from room temperature to 800°C over 8 hours. The temperature is then maintained at 800°C for 50 hours to ensure that the raw materials are completely melted and to obtain a pre-made alloy melt.

[0069] The pre-formed alloy melt was cooled and crystallized at a rate of 1℃ / h, allowing the sample to precipitate crystals during the process. When the temperature was lowered to 520℃, the quartz tube was inverted and placed in a centrifuge to separate the excess Sn. The sample was then cooled to room temperature in air to obtain a Co-As-Sn single crystal alloy.

[0070] Example 3

[0071] In an argon-filled glove box, Co powder (purity 2N8, purchased from Alfa), As powder (purity 5N, purchased from Aladdin), and Sn granules (purity 5N, purchased from Sinopharm Reagent Network) were mixed, and the mixture was placed in an alumina crucible; wherein the molar ratio of Co powder, As powder, and Sn granules was 1.05:0.85:9.5.

[0072] An alumina crucible is placed in a quartz tube and stuffed with quartz wool. Argon gas is extracted from the quartz tube using a mechanical pump-molecular pump assembly, and the quartz tube is then sealed. The sealed quartz tube is placed in a box furnace for heating, and the temperature is raised from room temperature to 830°C over 8 hours. The temperature is then maintained at 830°C for 60 hours to ensure that the raw materials are completely melted and to obtain a pre-made alloy melt.

[0073] The pre-formed alloy melt was cooled and crystallized at a rate of 3℃ / h, allowing the sample to precipitate crystals during the process. When the temperature was lowered to 550℃, the quartz tube was inverted and placed in a centrifuge to separate the excess Sn. The sample was then cooled to room temperature in air to obtain a Co-As-Sn single crystal alloy.

[0074] Example 4

[0075] In an argon-filled glove box, Co powder (purity 2N8, purchased from Alfa), As powder (purity 5N, purchased from Aladdin), and Sn granules (purity 5N, purchased from Sinopharm Reagent Network) were mixed, and the mixture was placed in an alumina crucible; wherein the molar ratio of Co powder, As powder, and Sn granules was 1:0.8:10.

[0076] An alumina crucible is placed in a quartz tube and stuffed with quartz wool. Argon gas is extracted from the quartz tube using a mechanical pump-molecular pump assembly, and the quartz tube is then sealed. The sealed quartz tube is placed in a box furnace for heating, and the temperature is raised from room temperature to 850°C over 8.5 hours. The temperature is then maintained at 850°C for 60 hours to ensure that the raw materials are completely melted, thus obtaining a pre-made alloy melt.

[0077] The pre-formed alloy melt was cooled and crystallized at a rate of 2℃ / h, allowing the sample to precipitate crystals during the process. When the temperature was lowered to 500℃, the quartz tube was inverted and placed in a centrifuge to separate the excess Sn. The sample was then cooled to room temperature in air to obtain a Co-As-Sn single crystal alloy.

[0078] In summary, this invention provides a Co-As-Sn single-crystal alloy, its preparation method, and its application. This invention prepares a Co-As-Sn single-crystal alloy by doping Co and As with Sn. Sn doping alters the alloy's band structure and Berry curvature, thereby affecting its magnetoresistance behavior. This allows the prepared Co-As-Sn single-crystal alloy to function normally as a linear magnetoresistance material at low temperatures, with a wider operating temperature range, thus better meeting the needs of magnetic sensors and enabling magnetic sensors to play an important role in more fields.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A Co-As-Sn single-crystal alloy, characterized in that, It includes Co, As and Sn, wherein the molar ratio of Co, As and Sn is (0.95~1.05):(0.75~0.85):(0.33~0.43).

2. The method for preparing Co-As-Sn single crystal alloy as described in claim 1, characterized in that, include: Co powder, As powder and Sn particles are mixed to obtain a mixture; wherein the molar ratio of Co powder, As powder and Sn particles is (0.95~1.05):(0.75~0.85):(9~11). The mixture is heated and melted to obtain a pre-formulated alloy melt; wherein the heating and melting temperature is 800℃~850℃ and the holding time is 48~60h; The pre-formed alloy melt is cooled and crystallized, and excess Sn is separated to obtain a Co-As-Sn single crystal alloy; wherein the heating and melting and cooling and crystallization are both carried out under vacuum conditions.

3. The method for preparing Co-As-Sn single crystal alloy according to claim 2, characterized in that, The heating and melting time is 8 to 8.5 hours.

4. The method for preparing Co-As-Sn single crystal alloy according to claim 2, characterized in that, The cooling rate for the cooling crystallization is 1–3 °C / h.

5. The method for preparing Co-As-Sn single crystal alloy according to claim 2, characterized in that, The method for cooling and crystallizing the pre-formed alloy melt and separating the excess Sn to obtain a Co-As-Sn single crystal alloy is as follows: The pre-formed alloy melt was cooled to 500℃~550℃ at a cooling rate of 1~3℃ / h to separate the excess Sn and obtain Co-As-Sn single crystal alloy melt. Co-As-Sn single crystal alloy melt is cooled to room temperature in air to obtain Co-As-Sn single crystal alloy.

6. A Co-As-Sn single-crystal alloy, characterized in that, The Co-As-Sn single crystal alloy prepared by the method according to any one of claims 2-5 has an operating temperature range of 2K to 300K.

7. The application of the Co-As-Sn single crystal alloy as described in claim 1 or 6 in magnetic sensors.

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