Two-dimensional Van der Waals magnet and preparation method and application thereof
By introducing Fe vacancy into the two-dimensional van der Waals magnet Fe2.8PdxGaTe2 to break the crystal symmetry and induce the generation of DMI, the problem that existing magnetic van der Waals materials cannot form high-density and small-size magnetic sgmidons at room temperature is solved, and its widespread application in magnetic memory devices is achieved.
Patent Information
- Application Number
- CN202510050934.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2025-05-06
AI Technical Summary
The existing magnetic van der Waals materials are unable to induce the formation of high-density, small-size magnetic sgmidons at room temperature, limiting their application in magnetic memory devices.
The crystal symmetry is broken by introducing Fe vacancies and DMI is induced, thereby forming high-density, small-size magnetic sgmidons in the two-dimensional van der Waals magnet Fe2.8PdxGaTe2.
High-density, small-size (<50nm) magnetic sgnetone was successfully induced at room temperature, broadening the application range of magnetic van der Waals materials in magnetic memory devices.
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Figure CN119943517A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of information storage technology, and in particular to a two-dimensional van der Waals magnet and a preparation method and application thereof. Background Art
[0002] With the rapid development of information technology, the demand for data storage and processing is increasing. Although traditional magnetic storage technology has achieved large-scale data storage, its storage density and energy consumption issues have gradually become the key bottlenecks restricting its development. Therefore, people have been looking for new magnetic storage media and technologies to create magnetic storage devices with higher storage density, faster response speed and lower energy consumption. In recent years, the discovery of new topological magnetic structures represented by magnetic skyrmions (hereinafter referred to as skyrmions) has provided an opportunity for the development of new magnetic storage devices with high density, high speed and low energy consumption.
[0003] Skyrmions are magnetic domain structures with topological vortex configurations. Their formation mainly depends on the Dzyaloshinskii-Moriya interaction (DMI), which is generated by the symmetry breaking of the crystal structure. Magnetic skyrmions were first discovered in chiral magnets, but in recent years they have been studied in full swing in magnetic van der Waals (vdW) materials. Fe3GaTe2 (FGT) is a type of centrosymmetric magnet (space group P63 / mmc) with a high Curie temperature (T C =380K) and strong perpendicular magnetic anisotropy, it is one of the few room temperature magnetic vdW materials. Since this material is a centrosymmetric magnet, DM interaction cannot be generated in it, so high-density magnetic skyrmions cannot be formed, which seriously hinders the application of existing magnetic vdW materials in magnetic storage devices. Introducing a portion of Fe vacancies in FGT can break the crystal symmetry of FGT to induce DMI and thus form skyrmions, but it is metastable. Therefore, how to break the crystal symmetry in magnetic vdW materials to induce DMI and successfully achieve room temperature, small size, and high-density magnetic skyrmions is a problem that needs to be solved in this field. Summary of the invention
[0004] Based on this, the purpose of the present invention is to provide a two-dimensional van der Waals magnet and its preparation method and application. The two-dimensional van der Waals magnet can be induced to produce high-density, small-size (<50nm) magnetic skyrmions at room temperature and has a wide range of applications in magnetic storage devices.
[0005] The objective of the present invention is achieved through the following technical solutions:
[0006] In a first aspect, the present invention provides a two-dimensional van der Waals magnet having a chemical formula of Fe 2.8 Pdx GaTe2, where x = 0.1 ± 0.03.
[0007] Compared with the prior art, the two-dimensional van der Waals magnet provided by the present invention has excellent comprehensive performance and is an ideal candidate material for spin electronics devices such as magnetic storage and information conversion.
[0008] In a preferred embodiment, the paramagnetic transition temperature of the two-dimensional van der Waals magnet is 310-325K, and a high-density, small-sized magnetic skyrmion domain structure can be generated at room temperature, and the size of the magnetic skyrmion is less than 50 nm.
[0009] In a preferred embodiment, the two-dimensional van der Waals magnet is a dissociable single crystal bulk.
[0010] In a second aspect, the present invention also provides a method for preparing a two-dimensional van der Waals magnet, comprising the following steps: weighing raw materials in proportion, and then using a high temperature flux method to prepare Fe 2.8 Pd x GaTe2 single crystal material, where x = 0.1 ± 0.03.
[0011] In a preferred embodiment, Fe, Pd, Ga, and Te with a purity of 99.99% are weighed respectively in a ratio of 1:x:1:2, wherein x=0.1±0.03.
[0012] In a preferred embodiment, the weighed raw materials are placed in an alumina crucible, and then an alumina sieve plate and another alumina crucible are added, and then the whole is transferred into a quartz tube and vacuum-sealed. The vacuum degree in the quartz tube is maintained at 5×10 - 3 Pa or less; after heating to 1000°C and keeping it for 24 to 72 hours, and then gradually cooling to 760 to 780°C and keeping it for at least 60 hours, the quartz tube is quickly transferred from the furnace body to a centrifuge for centrifugal treatment to separate the solvent from the single crystal sample, thereby obtaining (Fe 1-x Pd x )3GaTe2 single crystal bulk sample.
[0013] In a preferred embodiment, when heating, the temperature is set to rise from 30°C to 1000°C over 10 hours; when cooling, it is first cooled to 880°C at a cooling rate of 120°C / hour, and then cooled to 760°C at a cooling rate of 1°C / hour.
[0014] The main raw materials Fe, Ga and Te required for the preparation method of the two-dimensional van der Waals magnet provided by the present invention are all low-priced, abundant and easy-to-store elements. The preparation process of the material is simple and reliable, the process stability is good, and it is easy to industrialize the production.
[0015] In a third aspect, the present invention further provides a magnetic storage material, which comprises any two-dimensional van der Waals magnet as described above.
[0016] In a fourth aspect, the present invention also provides the use of any of the two-dimensional van der Waals magnets described above in spin electronics devices.
[0017] The two-dimensional van der Waals magnet provided by the present invention can be induced to produce high-density, small-size (<50nm) magnetic skyrmions at room temperature, which solves a major defect of existing magnetic van der Waals materials. The two-dimensional van der Waals magnet can be dissociated into atomic-level flakes as the magnetic layer in the magnetic heterojunction, and the magnetic skyrmions can be used as magnetic storage media. The high-density skyrmions of the two-dimensional van der Waals magnet can provide a solution for high-density magnetic storage devices, greatly broadening the application scope of magnetic van der Waals materials, and is expected to be widely used in magnetic storage devices.
[0018] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is Fe in Example 1 of the present invention 2.8 Pd x Temperature vs. time during GaTe2 single crystal growth
[0020] Figure 2 The Fe prepared in Example 1 of the present invention 2.8 Pd x Optical view of GaTe2 single crystal bulk
[0021] Figure 3 The Fe prepared in Example 1 of the present invention 2.8 Pd x Scanning electron microscope characterization and energy dispersive X-ray spectroscopy elemental analysis of GaTe2 single crystal
[0022] Figure 4 Fe prepared in Example 1 2.8 Pd x Thermomagnetic curve (a) and magnetization curve (b) of GaTe2 single crystal bulk
[0023] Figure 5 Fe prepared in Example 1 2.8 Pd x Electron microscope photograph of the magnetic domain structure evolution of GaTe2 single crystal sample at room temperature with changing magnetic field and a curve of skyrmion size changing with external magnetic field DETAILED DESCRIPTION
[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.
[0025] The two-dimensional van der Waals magnet provided by the present invention and its preparation method and application are specifically described below.
[0026] The present invention provides a two-dimensional van der Waals magnet, whose chemical formula is Fe 2.8 Pd x GaTe2, wherein x = 0.1 ± 0.03. For example, x can be 0.07, 0.08, 0.09, 0.1, 0.11, 0.12 or 0.13, or any other value within the range of 0.07 to 0.13.
[0027] Furthermore, the paramagnetic transition temperature of the two-dimensional van der Waals magnet of the present invention is 310-325K, and it can produce a high-density, small-sized magnetic skyrmion magnetic domain structure at room temperature, and the size of the magnetic skyrmion is less than 50nm. The two-dimensional van der Waals magnet is the magnetic skyrmion material system with the smallest size at room temperature among the currently known two-dimensional van der Waals materials, which solves a major defect of existing magnetic van der Waals materials and greatly broadens the application range of magnetic van der Waals materials.
[0028] Furthermore, the two-dimensional van der Waals magnet of the present invention is a dissociable single crystal block.
[0029] Accordingly, the present invention also provides a method for preparing the above-mentioned two-dimensional van der Waals magnet, comprising the following steps:
[0030] Weigh the raw materials in proportion, and then use the high-temperature flux method to prepare Fe 2.8 Pd x GaTe2 single crystal material, where x = 0.1 ± 0.03.
[0031] Specifically, Fe, Pd, Ga, and Te with a purity of 99.99% are weighed in a ratio of 1:x:1:2, wherein x=0.1±0.03. For example, Fe, Pd, Ga, and Te with a purity of 99.99% are weighed in a ratio of 1:0.07:1:2, 1:0.08:1:2, 1:0.09:1:2, 1:0.1:1:2, 1:0.11:1:2, 1:0.12:1:2, or 1:0.13:1:2, or any other ratio in the range of 1:(0.07-0.13):1:2, wherein Fe prepared in a ratio of 1:0.1:1:2 is 2.8 Pd x GaTe2 single crystal material has the best performance.
[0032] For reference, the high temperature solvent method specifically includes the following steps: the weighed raw materials are placed in an alumina crucible, and then an alumina sieve plate and another alumina crucible are added, and then the whole is transferred into a quartz tube and vacuum sealed. The vacuum degree in the quartz tube is maintained at 5×10 -3 Pa; after heating to 1000 ° C and keeping it for 24 to 72 hours, and then gradually cooling to 760 to 780 ° C and keeping it for at least 60 hours, the quartz tube is quickly transferred from the furnace to a centrifuge for centrifugal treatment to separate the solvent from the single crystal sample, thereby obtaining Fe 2.8 Pd x GaTe2 single crystal bulk sample. For example, the temperature is raised to 1000°C and then kept at that temperature for 24h, 48h or 72h, or any other value within the range of 24 to 72h, and then gradually cooled to 760°C, 770°C or 780°C, or any other value within the range of 760 to 780°C.
[0033] For reference, when heating, the set temperature was raised from 30°C to 1000°C over 10 hours; when cooling, it was first lowered to 880°C at a cooling rate of 120°C / hour, and then lowered to 760°C at a cooling rate of 1°C / hour.
[0034] Correspondingly, the present invention also provides a magnetic storage material, which includes any two-dimensional van der Waals magnet as described above. The two-dimensional van der Waals magnet provides an ideal material for the research and development of new magnetic storage materials and is expected to be widely used.
[0035] Accordingly, the present invention also provides the application of any of the above two-dimensional van der Waals magnets in spin electronics devices. Two-dimensional van der Waals magnets can induce the generation of high-density, small-size (<50nm) magnetic skyrmions at room temperature, solving a major defect of existing magnetic van der Waals materials, greatly broadening the application scope of magnetic van der Waals materials, and are expected to be widely used in spin electronics devices.
[0036] The following is the best embodiment of the present invention. It should be noted that the various parameter values used in the embodiments are all preferred parameter values within the parameter range limited by the claims. In other embodiments, as long as the adopted parameter values are within the scope of the claims, the purpose of the present invention can be achieved.
[0037] Example 1
[0038] This embodiment provides a two-dimensional van der Waals magnet and a preparation method thereof, wherein the chemical formula is Fe 2.8 Pd 0.1 GaTe2. Its preparation method comprises the following steps:
[0039] S1: According to the ratio of Fe:Pd:Ga:Te=1:0.1:1:2, weigh Fe, Pd, Ga, and Te raw materials with a purity of 99.99% respectively;
[0040] S2: Put the weighed raw materials into an alumina crucible, add an alumina sieve plate and another alumina crucible on the alumina crucible with the raw materials. Then transfer the whole into a quartz tube, seal the quartz tube with vacuum, and set the vacuum degree in the quartz tube to 4×10 -3 Pa;
[0041] S3: Transfer the vacuum quartz tube to the pit furnace for material growth. Figure 1 The specific growth patterns are as follows:
[0042] The first step is to set the temperature from 30°C to 1000°C over 10 hours, then reduce it to 880°C at a cooling rate of 120°C / hour after keeping it for 24 hours, then reduce it to 760°C at a cooling rate of 1°C / hour, and keep it at 760°C for at least 60 hours. The second step is to transfer the quartz tube to a low-speed centrifuge for centrifugation at 3000 revolutions per minute for 5 minutes to separate the flux and the grown single crystal. The Te in the raw material is also a solvent. The third step is to place the quartz tube in water and cool it to room temperature to obtain a Fe 2.8 Pd x GaTe2 single crystal, such as Figure 2 shown.
[0043] Test Example 1
[0044] The Fe prepared in Example 1 of the present invention was analyzed by a scanning electron microscope (SEM) with an energy dispersive X-ray spectrometer (EDS). 2.8 Pd x The GaTe2 single crystal samples were subjected to elemental characterization analysis. Figure 3 As shown, Figure 3 (a) and (b) are SEM and EDS characterization images of different samples prepared in Example 1. It can be seen from the figure that the four elements Fe, Pd, Ga, and Te are evenly distributed. 2.8 Pd x The elemental analysis results of GaTe2 samples show that the average atomic ratio is about Fe 2.796± 0.24 Pd 0.0788±0.008 GaTe 1.868±0.16X-ray diffraction can be used to determine that the single crystal sample prepared in Example 1 has a non-centrosymmetric space group P3m1 and a lattice parameter
[0046] Test Example 2
[0047] The Fe prepared in Example 1 was measured by a comprehensive physical property measurement system (PPMS). 2.8 Pd x The GaTe2 single crystal sample was subjected to the measurement of thermomagnetic curve and magnetization curve. Its Curie temperature (T C ) is about 310K. The sample is paramagnetic above 310K and ferromagnetic below 310K, such as Figure 4 (a) shown. Figure 4 (b) shows the magnetization curves of the sample in the in-plane and out-of-plane directions at 300K, indicating that it has weak magnetocrystalline anisotropy and the easy magnetization direction is along the
[001] crystal direction, which is conducive to the induction of magnetic skyrmions at room temperature.
[0048] Test Example 3
[0049] The room temperature microscopic magnetic domain structure of the sample was observed using a Lorentz transmission electron microscope. Figure 5 As shown in Figure 1, (a) is a photograph of the magnetic domains of the sample without an external magnetic field. As can be seen from the figure, the sample spontaneously appears stripe domains with a period of about 93nm. As the external magnetic field increases, B = 23.6mT, the stripe domains gradually shrink and break from the middle to form local magnetic skyrmions. As the external magnetic field further increases to B = 34.8 ~ 68.8mT, as shown in Figure 1, Figure 5 (b) and (c), the stripe magnetic domains are completely transformed into magnetic skyrmions, and the size of skyrmions decreases with the increase of the external magnetic field, and the size remains at about 50 to 38 nm. When the external magnetic field reaches 80.3 mT or above, Figure 5 (d), the magnetic skyrmions all disappear, and the sample becomes a fully saturated ferromagnetic state. The size of the magnetic skyrmions changes with the applied magnetic field, such as Figure 5 (e) as shown.
[0050] In summary, compared to the prior art, the two-dimensional van der Waals magnet provided by the present invention can induce high-density, small-size (<50nm) magnetic skyrmions at room temperature through an external magnetic field. The two-dimensional van der Waals magnet is the magnetic skyrmion material system with the smallest size at room temperature among the currently known two-dimensional van der Waals materials, which well solves a major defect of existing magnetic van der Waals materials and greatly broadens the application range of magnetic van der Waals materials. It can be seen from the test examples that the two-dimensional van der Waals magnet provided by the present invention has excellent comprehensive performance and is an ideal candidate material for spin electronics devices such as magnetic storage and information conversion. At the same time, the main raw materials Fe, Ga, and Te in the preparation of the two-dimensional van der Waals magnet are low-priced, abundant in reserves, and easy to store elements, and the preparation process is simple and reliable, with good process stability, and easy to industrialize.
[0051] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.
Claims
1. A two-dimensional van der Waals magnet, characterized in that: Its chemical formula Fe 2.8 Pd x GaTe2, where x = 0.1 ± 0.
03.
2. The two-dimensional van der Waals magnet according to claim 1, characterized in that: The paramagnetic transition temperature is 310-325K, and the two-dimensional van der Waals magnet can generate a high-density, small-sized magnetic skyrmion magnetic domain structure at room temperature, and the size of the magnetic skyrmion is less than 50nm.
3. The two-dimensional van der Waals magnet according to claim 1, characterized in that: It is a dissociable single crystal bulk.
4. A method for preparing a two-dimensional van der Waals magnet as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Weigh the raw materials in proportion, and then use the high-temperature flux method to prepare Fe 2.8 Pd x GaTe2 single crystal material, where x = 0.1 ± 0.
03.
5. The preparation method according to claim 4, characterized in that: Fe, Pd, Ga and Te with a purity of 99.99% were weighed respectively in a ratio of 1:x:1:2, wherein x=0.1±0.
03.
6. The preparation method according to claim 4, characterized in that: The weighed raw materials were placed in an alumina crucible, and then an alumina sieve plate and another alumina crucible were added. The whole was then transferred into a quartz tube and vacuum-sealed. The vacuum degree in the quartz tube was maintained at 5×10 -3 Pa; after heating to 1000 ° C and keeping it for 24 to 72 hours, and then gradually cooling to 760 to 780 ° C and keeping it for at least 60 hours, the quartz tube is quickly transferred from the furnace to a centrifuge for centrifugal treatment to separate the solvent from the single crystal sample, thereby obtaining Fe 2.8 Pd x GaTe2 single crystal bulk sample.
7. The preparation method according to claim 6, characterized in that: When heating, the set temperature was raised from 30°C to 1000°C over 10 hours; when cooling, it was first lowered to 880°C at a cooling rate of 120°C / hour, and then lowered to 760°C at a cooling rate of 1°C / hour.
8. A magnetic storage material, characterized in that: It comprises the two-dimensional van der Waals magnet as described in any one of claims 1 to 3.
9. Use of the two-dimensional van der Waals magnet according to any one of claims 1 to 3 in a spin electronics device.