Large-size CuCrP2S6 single crystal and preparation method thereof
By employing chemical vapor transport and vacuum sealing technology in a dual-temperature zone tube furnace for heating treatment, the problem of preparing large-size CuCrP2S6 single crystals in existing technologies has been solved, realizing a high-quality and simple preparation method and obtaining large-size CuCrP2S6 single crystals.
Patent Information
- Application Number
- CN202411347719.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2025-01-10
AI Technical Summary
Existing technologies make it difficult to prepare large-size, high-quality CuCrP2S6 single crystals using simple and low-cost methods. Traditional methods are cumbersome and prone to introducing impurities.
Large-size CuCrP2S6 single crystals were prepared by using chemical vapor transport (CVT) and vacuum sealing technology. After vacuum sealing a quartz tube containing a mixture of elemental copper, chromium, phosphorus, and sulfur, the tube was heated in a dual-temperature zone tube furnace, with the temperature and time controlled in the high and low temperature zones.
The preparation process was simplified, the introduction of impurity elements was avoided, and high-quality large-size CuCrP2S6 single crystals were obtained, with a size of up to 1 cm, which is better than the 0.5 cm of the traditional method.
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Figure CN119287500A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of crystal material preparation, and in particular relates to a method for preparing CuCrP2S6 single crystal by chemical vapor transport (CVT) and vacuum tube sealing technology. Background Art
[0002] CuCrP2S6 is a two-dimensional multiferroic material. Its unique magnetic and electrical properties make it of great research value in many research fields such as magnetic storage materials, magnetic sensors, and new electronic devices. However, traditional single crystal preparation methods (including solution method, high-temperature solid phase method, hydrothermal method, etc.) are often difficult to prepare large-sized CuCrP2S6 single crystals through simple and low-cost operation methods. Existing processes often require pre-treatment of raw materials such as grinding and melting, which is not only cumbersome, but also easy to introduce impurities, affecting the raw material ratio, and the crystal size is small.
[0003] Therefore, it is very necessary to develop simple, effective and high-quality preparation technology and process for large-sized CuCrP2S6 single crystals for related scientific research and application of this material. Summary of the invention
[0004] In view of the above technical problems, the purpose of the present invention is to provide a method for preparing high-quality large-size CuCrP2S6 single crystals which is simple to operate, stable and effective.
[0005] In a first aspect, the present invention provides a method for preparing a large-sized CuCrP2S6 single crystal, the preparation method comprising the following steps: (1) weighing single copper (Cu), single chromium (Cr), single phosphorus (P) and single sulfur (S) as raw materials according to the stoichiometric ratio of elements in CuCrP2S6 (Cu:Cr:P:S=1:1:2:6), mixing them and placing them at the bottom of a quartz tube, evacuating the quartz tube to a vacuum and heat-sealing it; (2) placing the heat-sealed vacuum quartz tube into a dual-temperature zone tube furnace, placing the bottom end where the mixed raw materials are placed in the high temperature zone and the other end in the low temperature zone, cooling the tube to room temperature after heating treatment, and obtaining the large-sized CuCrP2S6 single crystal in the low temperature zone.
[0006] Preferably, step (1) further includes adding elemental iodine I2 as a carrier gas for subsequent crystal generation when the raw materials are added to the quartz tube; preferably, the amount of elemental iodine I2 added is 0.001 to 0.003 g.
[0007] Preferably, the single substance raw material is in powder form to ensure the uniformity of mixing, preferably with a particle size of 50 to 150 microns and a purity of ≥99.99%.
[0008] Preferably, in step (1), the length of the quartz tube is 15 to 25 cm, and the inner diameter is 15 to 25 mm.
[0009] Preferably, in step (1), the vacuum degree in the quartz tube is less than 1 Pa; and the heat sealing of the quartz tube is performed using a hydrogen-oxygen mixed flame.
[0010] Preferably, in step (2), the temperature of the high temperature zone is set to 690-710°C, and the heating rate is 2-10°C / min; preferably, the temperature of the high temperature zone is 700°C, and the heating rate is 10°C / min.
[0011] Preferably, in step (2), the temperature of the low temperature zone is set to 590-610°C, and the heating rate is 2-10°C / min; preferably, the temperature of the low temperature zone is 600°C, and the heating rate is 10°C / min.
[0012] Preferably, in step (2), the temperature difference between the high temperature zone and the low temperature zone is 90-110°C, preferably 100°C.
[0013] Preferably, in step (2), the heating treatment time is 7 to 10 days, preferably 7 days; and the temperature is lowered to room temperature by natural cooling in the furnace.
[0014] In a second aspect, the present invention provides a large-sized CuCrP2S6 single crystal obtained according to the above-mentioned preparation method.
[0015] Beneficial Effects The preparation method (CVT) of large-size CuCrP2S6 single crystals provided by the present invention is simple to operate, stable and effective, and does not require complicated pre-treatment processes such as grinding and melting. It simplifies the reaction steps and can effectively avoid the participation of impurity elements in the reaction. The CuCrP2S6 single crystals prepared by this method have good quality and can reach a size of 1 cm, which is much larger than the maximum size of 0.5 cm in traditional processes. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 Schematic diagram of the method for preparing large-sized CuCrP2S6 single crystals by chemical vapor transport method according to the present invention; Figure 2 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 1; Figure 3 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 2; Figure 4 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 3; Figure 5 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 4; Figure 6 X-ray diffraction pattern of the CuCrP2S6 single crystal prepared in Example 4; Figure 7 This is a physical picture of the crystal prepared in Comparative Example 1; Figure 8 This is a physical picture of the crystal prepared in Comparative Example 2; Fig. 9 This is the X-ray diffraction pattern of the crystal prepared in Comparative Example 2. DETAILED DESCRIPTION
[0017] The present invention is further described below by the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention, but not to limit the present invention.
[0018] The following, combined Figure 1 , exemplarily illustrating the preparation method of the large-sized CuCrP2S6 single crystal provided by the present invention. The preparation method may include the following steps: (1) weighing single copper (Cu), single chromium (Cr), single phosphorus (P) and single sulfur (S) as raw materials according to the stoichiometric ratio of elements in CuCrP2S6 (Cu:Cr:P:S=1:1:2:6), mixing them and placing them at the bottom of a quartz tube, evacuating the quartz tube to a vacuum and heat-sealing it; (2) placing the heat-sealed vacuum quartz tube into a dual-temperature zone tube furnace, placing the bottom end of the mixed raw material in the high temperature zone and the other end in the low temperature zone, cooling to room temperature after heating treatment, and obtaining the large-sized CuCrP2S6 single crystal in the low temperature zone.
[0019] In some embodiments, step (1) may further include adding elemental iodine I2 as a carrier gas for subsequent crystal generation while adding the raw material to the quartz tube; preferably, the amount of elemental iodine I2 added may be 0.001 to 0.003 g. If the amount of elemental iodine I2 is too low, the size of the final prepared crystal will be small; if the amount is too high, it is easy to cause the I2 elemental to react with the raw material.
[0020] In some embodiments, in step (1), the single substance raw material may be in powder form to ensure mixing uniformity, and the preferred particle size may be 50 to 150 microns; the purity may be controlled to be ≥99.99%.
[0021] In some embodiments, in step (1), the length of the quartz tube can be 15 to 25 cm, and the inner diameter can be 15 to 25 mm. If the length of the quartz tube is too short, the temperature difference between the high temperature zone and the low temperature zone will be too small to control the temperature difference, which will eventually affect the smooth production of crystals; if the length is too long, the efficiency will be reduced and the energy consumption will be increased. At the same time, if the inner diameter of the quartz tube is too small, it is easy to cause the crystal size to be too small.
[0022] In some embodiments, in step (1), the vacuum degree in the quartz tube can be controlled to be less than 1 Pa. If the vacuum degree in the quartz tube is not enough, impurities in the air may interfere with the reaction.
[0023] In some embodiments, in step (1), heat sealing of the quartz tube can be performed using a hydrogen-oxygen mixed flame.
[0024] In some embodiments, in step (2), the temperature of the high temperature zone can be set to 690-710°C, and the heating rate can be 2-10°C / min; preferably, the temperature of the high temperature zone is 700°C, and the heating rate is 10°C / min. If the temperature of the high temperature zone is too high, defects will be generated during the crystal growth process, reducing the crystal quality; if the temperature is too low, the crystal growth will be too slow, thereby prolonging the reaction period, or even incomplete reaction.
[0025] In some embodiments, in step (2), the temperature of the low temperature zone can be set to 590-610°C, and the heating rate can be 2-10°C / min; preferably, the temperature of the low temperature zone is 600°C, and the heating rate is 10°C / min.
[0026] In some embodiments, in step (2), the temperature difference between the high temperature zone and the low temperature zone may be 90-110° C., preferably 100° C. If the temperature difference between the high and low temperature zones is too small, the reaction rate will be reduced and the reaction time will be prolonged; if the temperature difference is too large, defects will be generated inside the crystal.
[0027] In some embodiments, in step (2), the heating treatment time can be 7 to 10 days, preferably 7 days. If the reaction time is too short, the crystal growth will be incomplete, resulting in defects or polycrystalline materials; if the reaction time is too long, the energy consumption will be too high and the reaction efficiency will be reduced.
[0028] In some embodiments, in step (2), the temperature is lowered to room temperature by natural cooling in the furnace.
[0029] The present invention is based on high-purity single copper Cu, chromium Cr, phosphorus P, and sulfur S as raw materials, and effectively prepares high-quality large-sized CuCrP2S6 single crystals through vacuum sealing and chemical vapor transport technology (CVT). The preparation method is simple to operate, stable and effective. Among them, the conditions such as the temperature in the high and low temperature zones, the reaction time, the vacuum degree of the quartz tube, the temperature difference in the high and low temperature zones during the crystal growth process will have a certain degree of influence on the quality of the prepared single crystal. The CuCrP2S6 single crystal obtained by the preparation method provided by the present invention has a large size.
[0030] The following further examples are given to explain the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present invention belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are only an example in a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description of this article, and are not limited to the specific values exemplified below. If not otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art; the picture is taken by taking a picture of the prepared crystal sample with a centimeter ruler as a reference, and the size of the prepared crystal sample is generally mm level, and the maximum can reach 1cm.
[0031] Example 1
[0032] The method for preparing a large-sized CuCrP2S6 single crystal provided in this embodiment comprises the following steps: (1) Cleaning the quartz tube with deionized water and placing it in an oven to dry it at 102° C. for 0.5 h; weighing and evenly mixing single element Cu, single element Cr, single element P, and single element S according to the element molar ratio of 1:1:2:6 and placing them in the quartz tube; evacuating the quartz tube with a vacuum pump, and then sintering the quartz tube mouth with a hydrogen-oxygen mixed flame to make it sealed. (2) The vacuum-sealed quartz tube was placed horizontally in a dual-zone tubular furnace for heating reaction treatment. The high temperature zone of the dual-zone tubular furnace was heated to 700°C after 300 minutes, and the low temperature zone was heated to 600°C after 300 minutes. The temperature was maintained constant for 7 days and then naturally cooled to room temperature with the furnace to obtain a CuCrP2S6 single crystal from the low temperature end of the quartz tube.
[0033] Figure 2 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 1. As can be seen from the figure, the size of the CuCrP2S6 sample prepared in Example 1 is about 5 mm.
[0034] Example 2
[0035] The preparation method of the large-sized CuCrP2S6 single crystal provided in this embodiment refers to that in Embodiment 1, the main difference is that in step (1), 0.002 g of elemental iodine I2 is added together with the raw material into the quartz tube as a carrier gas for subsequent crystal generation.
[0036] Figure 3 This is a real picture of the CuCrP2S6 single crystal prepared in Example 2. As can be seen from the figure, the length of the prepared CuCrP2S6 sample is close to 10 mm, and the surface is smoother and flatter.
[0037] Example 3
[0038] The preparation method of the large-sized CuCrP2S6 single crystal provided in this embodiment is similar to that in Embodiment 1, except that: in step (1), 0.001 g of elemental iodine I2 is added to the quartz tube at the same time as the raw material is added as a carrier gas for subsequent crystal generation; In step (2), the high temperature zone of the dual-temperature zone tubular furnace is heated to 700° C. at 10° C. / min, and the low temperature zone is heated to 600° C. at 10° C. / min. After maintaining the temperature unchanged for 7 days, the reaction is naturally cooled to room temperature along with the furnace.
[0039] Figure 4 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 3. As can be seen from the figure, the surface of the prepared CuCrP2S6 sample is smooth and flat, and has a size of 5 mm.
[0040] Example 4
[0041] The preparation method of the large-sized CuCrP2S6 single crystal provided in this embodiment refers to that in Embodiment 1, the main difference is that in step (1), 0.001 g of elemental iodine I2 is added together with the raw material into the quartz tube as a carrier gas for subsequent crystal generation.
[0042] Figure 5 This is a physical picture of the CuCrP2S6 single crystal prepared in Example 4. As can be seen from the figure, the prepared CuCrP2S6 sample has a large size of 10 mm.
[0043] Figure 6 This is the X-ray diffraction pattern of the CuCrP2S6 single crystal prepared in Example 4. As can be seen from the figure, the prepared CuCrP2S6 sample has only three diffraction peaks in the same direction: (002), (004), and (006).
[0044] Comparative Example 1
[0045] The preparation method of the crystal provided in this comparative example refers to Example 1, with the main difference being: In step (2), the high temperature zone of the dual-temperature zone tubular furnace is heated to 600° C. after 300 min, and the low temperature zone is heated to 500° C. after 300 min. The temperature is maintained constant for 7 days and then naturally cooled to room temperature along with the furnace.
[0046] Figure 7 This is a real picture of the crystal prepared in Comparative Example 1. It can be seen from the figure that only a small amount of small-sized crystals are generated in the low temperature area of the quartz tube under the preparation process of this comparative example.
[0047] Comparative Example 2
[0048] The preparation method of the crystal provided in this comparative example refers to Example 1, with the main difference being: In step (2), the reaction time for maintaining the temperature constant is set to 4 days, and the furnace is naturally cooled to room temperature.
[0049] Figure 8 This is a real picture of the crystal prepared in Comparative Example 2. It can be seen from the figure that only small-sized crystals are generated in the low-temperature zone of the quartz tube under the preparation process of this comparative example.
[0050] Fig. 9 This is the X-ray diffraction pattern of the crystal prepared in Comparative Example 2. It can be seen from the figure that the prepared crystal is a polycrystalline material.
[0051] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.
Claims
1. A method for preparing a large-size CuCrP2S6 single crystal, characterized in that: The preparation method comprises the following steps: (1) weighing single copper (Cu), single chromium (Cr), single phosphorus (P) and single sulfur (S) as raw materials according to the stoichiometric ratio of elements in CuCrP2S6 (Cu:Cr:P:S=1:1:2:6), mixing them and placing them at the bottom of a quartz tube, evacuating the quartz tube to a vacuum and heat-sealing it; (2) placing the heat-sealed vacuum quartz tube into a dual-temperature zone tube furnace, placing the bottom end where the mixed raw materials are placed in the high temperature zone and the other end in the low temperature zone, cooling the tube to room temperature after heating treatment, and obtaining the large-sized CuCrP2S6 single crystal in the low temperature zone.
2. The preparation method according to claim 1, characterized in that: In step (1), it also includes adding elemental iodine I2 as a carrier gas for subsequent crystal generation when adding the raw materials into the quartz tube; preferably, the amount of elemental iodine I2 added is 0.001 to 0.003 g.
3. The preparation method according to claim 1 or 2, characterized in that: In step (1), it also includes adding elemental iodine I2 as a carrier gas for subsequent crystal generation when adding the raw materials into the quartz tube; preferably, the amount of elemental iodine I2 added is 0.001 to 0.003 g.
4. The preparation method according to any one of claims 1 to 3, characterized in that In step (1), the length of the quartz tube is 15 to 25 cm, and the inner diameter is 15 to 25 mm.
5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (1), the vacuum degree in the quartz tube is less than 1 Pa; and the heat sealing of the quartz tube is performed using a hydrogen-oxygen mixed flame.
6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the temperature of the high temperature zone is set to 690-710°C, and the heating rate is 2-10°C / min; preferably, the temperature of the high temperature zone is 700°C, and the heating rate is 10°C / min.
7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (2), the temperature of the low temperature zone is set to 590-610°C, and the heating rate is 2-10°C / min; preferably, the temperature of the low temperature zone is 600°C, and the heating rate is 10°C / min.
8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (2), the temperature difference between the high temperature zone and the low temperature zone is 90-110°C, preferably 100°C.
9. The preparation method according to any one of claims 1 to 8, characterized in that: In step (2), the heating treatment time is 7 to 10 days, preferably 7 days; the temperature is lowered to room temperature by natural cooling in the furnace.
10. A large-sized CuCrP2S6 single crystal obtained by the preparation method according to any one of claims 1-9.