Multi-component alloy two-dimensional van der Waals Ga-based magnetic crystal, preparation and application

Abstract

The invention relates to a multi-component alloy two-dimensional van der Waals Ga-based magnetic crystal, preparation and application, and belongs to the technical field of nano magnetic materials. The magnetic crystal material is (Fe < 1-x > Ax) a (Ga < 1-y > By) b (Te < 1-z > Cz) c, wherein x, y and z are all greater than 0 and less than or equal to 0.9; a is equal to 2-6, b is equal to 0.1-2, and c is equal to 0.1-5; a is Ti, V, Cr, Mn, Cu or Zn, B is Al or In, and C is S, Se, Br, I or Sb. The multi-component alloy two-dimensional Van der Waals Ga-based magnetic crystal provided by the invention is a layered material, layers are connected through weak Van der Waals force, a multi-layer to single-layer nanosheet can be obtained through mechanical stripping, and a nano-scale spinning electronic device is easy to further prepare. According to different types and proportions of doped elements, the crystal respectively shows ferromagnetism or antiferromagnetism, and has a wide application prospect in spintronics.

Description

Technical Field

[0001] The present invention belongs to the technical field of nano-magnetic material preparation, and more specifically, relates to multi-element alloy two-dimensional van der Waals Ga-based magnetic crystals, preparation and application. Background Art

[0002] The discovery of two-dimensional magnetic materials has greatly promoted the development of two-dimensional spin electronics and information technology. Due to the interlayer van der Waals interaction, two-dimensional magnetic materials are easy to mechanically peel off, have atomically smooth surfaces and tunable physical properties, and can be used to construct van der Waals heterojunctions to prepare magnetic tunnel junctions, spin-orbit torque devices, spin-transfer torque devices, etc., thereby realizing memory computing based on non-volatile memory, neuromorphic computing and stochastic computing.

[0003] High-performance and low-power spin-function devices usually rely on current drive. Therefore, metallic magnetic materials have more advantages than insulating magnetic materials. However, the metallic two-dimensional van der Waals magnetic materials that have been discovered so far have problems such as magnetic transition temperature below room temperature, in-plane magnetic anisotropy, and low coercivity of ferromagnetic materials, which greatly limit their practical applications. Summary of the invention

[0004] The present invention provides a type of multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal, and the present invention can be used to prepare high-quality two-dimensional van der Waals Ga-based magnetic crystal. The magnetic crystal material of the present invention is (Fe 1-x A x ) a (Ga 1-y B y ) b (Te 1-z C z ) c, wherein x, y and z are all greater than 0 and less than or equal to 0.9; a=2-6, b=0.1-2, c=0.1-5; A is Ti, V, Cr, Mn, Cu or Zn, B is Al or In, and C is S, Se, Br, I or Sb. The magnetic crystal material in the present invention is a layered material, and the layers are connected by weak van der Waals forces. Multilayer to single-layer nanosheets can be obtained by mechanical peeling, which is easy to further prepare nanoscale spin electronic devices. In addition, according to the different types and proportions of the elements doped A, B, and C, the material exhibits ferromagnetism or antiferromagnetism, respectively. Correspondingly, its magnetic transition temperature is Curie temperature or Neel temperature, which can be adjusted in a wide range. The Curie temperature is 300-500K, the Neel temperature is 200-400K, and the magnetic transition temperature is close to or higher than room temperature; when the magnetic crystal is ferromagnetic, it has out-of-plane magnetic anisotropy and a coercive force of 0.4-2.5T, which can enhance the thermal stability in storage applications and improve the reliability of the device. The multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal of the present invention has metallic properties, can be driven by electric current and realize spin detection, and the fully two-dimensional van der Waals heterojunction constructed by the crystal has an atomically flat and smooth interface, which can realize high-performance spin electronic devices. In addition, the crystal has out-of-plane magnetic anisotropy, and can construct a heterojunction with a vertical structure, thereby improving the integration of the device. This solves the technical problems in the prior art that the two-dimensional van der Waals magnetic material has a magnetic transition temperature lower than room temperature, has in-plane magnetic anisotropy, and has a small coercive force when it is ferromagnetic.

[0005] According to a first aspect of the present invention, a multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal is provided, wherein the magnetic crystal material is (Fe 1-x A x ) a (Ga 1-y B y ) b (Te 1-z C z ) c , wherein x, y and z are all greater than 0 and less than or equal to 0.9; a=2~6, b=0.1~2, c=0.1~5; A is Ti, V, Cr, Mn, Cu or Zn, B is Al or In, and C is S, Se, Br, I or Sb.

[0006] Preferably, the multi-alloy two-dimensional van der Waals Ga-based magnetic crystal exhibits ferromagnetism below the Curie temperature or antiferromagnetism below the Neel temperature; the Curie temperature ranges from 300 to 500K, and the Neel temperature ranges from 200 to 400K.

[0007] Preferably, when the multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal exhibits ferromagnetism, the coercive force is 0.4-2.5T.

[0008] According to another aspect of the present invention, there is provided an application of any one of the multi-alloy two-dimensional van der Waals Ga-based magnetic crystals in ferromagnetic or antiferromagnetic spin electronics.

[0009] Preferably, the application is specifically an application in a magnetic tunnel junction device, a spin-orbit torque device, a spin-transfer torque device or an electrically controlled magnetic device.

[0010] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0011] (1) A type of multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal in the present invention exhibits ferromagnetism or antiferromagnetism depending on the type and proportion of the doped elements. Correspondingly, its magnetic transition temperature is the Curie temperature or the Neel temperature, which can be controlled over a wide range. The Curie temperature is 300-500K and the Neel temperature is 200-400K, which are higher than most of the known two-dimensional van der Waals metallic ferromagnetic or antiferromagnetic materials.

[0012] (2) When a type of multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal in the present invention is ferromagnetic, it has a large coercive force. The coercive force of the material is 0.4 to 2.5 T, which is higher than most known two-dimensional van der Waals magnetic materials. It can enhance the thermal stability in storage applications and improve the reliability of the device.

[0013] (3) The magnetic crystal material in the present invention is a two-dimensional van der Waals metal material with good crystallinity, high purity, and easy mechanical peeling.

[0014] (4) Due to its two-dimensional van der Waals properties and low surface roughness, the magnetic crystal material in the present invention can be seamlessly stacked with other two-dimensional materials without lattice mismatch problems. It can construct van der Waals heterojunctions with high interface quality and prepare magnetic tunnel junctions, spin-orbit torque devices, spin-transfer torque devices, etc., thereby realizing memory computing, neuromorphic computing and stochastic computing based on non-volatile memory. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Yes (Fe 0.9 Cu 0.1 )3Ga 0.8 Al 0.2 (Te 0.9 Se 0.1 )2 Zero-field cooling, field cooling curves and low-temperature hysteresis loop of the crystal under out-of-plane magnetic field.

[0016] Figure 2 Yes (Fe 0.8 Mn 0.2 )5(Ga 0.9 In 0.1 )2(Te0.7 Sb 0.3 )3 Zero-field cooling, field cooling curves and low-temperature hysteresis loop of the crystal under out-of-plane magnetic field.

[0017] Figure 3 Yes (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 Zero-field cooling, field cooling curves and low-temperature hysteresis loop of the crystal under out-of-plane magnetic field.

[0018] Figure 4 Based on (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2Performance curve of magnetic tunnel junction device based on two-dimensional nanosheet at 190K. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] The present invention discloses a novel multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal and its preparation, wherein the material (Fe 1-x A x ) a (Ga 1-y B y ) b (Te 1-z C z ) c (x=0~0.9, y=0~0.9, z=0~0.9; a=2~6, b=0.1~2, c=0.1~5; A is Ti, V, Cr, Mn, Cu or Zn, B is Al or In, C is S, Se, Br, I or Sb) is a two-dimensional van der Waals material, which can be obtained by mechanical exfoliation to obtain multi-layer to single-layer nanosheets, which is easy to further prepare nanoscale spin electronic devices.

[0021] The preparation method of the multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal of the present invention is a molten salt method, a chemical vapor transport method, a magnetron sputtering method or a molecular beam epitaxy method.

[0022] The novel multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal and its preparation are now further described in detail in conjunction with the following specific embodiments and accompanying drawings.

[0023] Example 1

[0024] 1) Preparation by self-solvent method (Fe 0.9 Cu 0.1 )3Ga 0.8 Al 0.2 (Te 0.9 Se 0.1 )2;

[0025] 2) Fe powder, Cu powder, Ga particles, Al particles, Te powder and Se powder with a molar ratio of Fe:Cu:Ga:Al:Te:Se=2.7:0.3:0.8:0.2:1.8:0.2 were mixed evenly, placed in an ampoule, and washed with Ar gas three times before vacuum sealing;

[0026] 3) Place the sealed ampoule in a muffle furnace, quickly heat it to 1000°C, and slowly cool it down at a rate of 1.5°C / h after sufficient reaction to obtain (Fe 0.9 Cu 0.1 )3Ga 0.8 Al 0.2 (Te 0.9 Se 0.1 )2Magnetic crystal.

[0027] Example 2

[0028] 1) Preparation by chemical vapor deposition (Fe 0.7 Cr 0.3 )3Ga 0.9 Al 0.1 (Te 0.9 Se 0.1 )2;

[0029] 2) Te, Se, FeCl2, CrCl3, GaI3 and AlCl3 powders are selected as precursors, SiO2 / Si with a diameter of 1 inch is used as a substrate, and in a three-zone CVD tube furnace, Se powder is placed in the upstream temperature zone 1 at a temperature of 200°C, Te powder is placed in the middle temperature zone 2 at a temperature of 420°C, a mixture of FeCl2, CrCl3, GaI3 and AlCl3 powders is placed in the downstream temperature zone 3 at a temperature of 600°C, and the substrate is placed downstream of the temperature zone 3;

[0030] 3) 100 sccm Ar gas was introduced, and after gas washing, 5 / 50 sccm of H2 / Ar mixed gas was introduced. The three-zone tube furnace was quickly heated to the target temperature for 30 minutes. After natural cooling, the (Fe2O3) deposited on the SiO2 / Si substrate was obtained. 0.7 Cr 0.3 )3Ga 0.9 Al 0.1 (Te 0.9 Se 0.1 )2 crystals.

[0031] Example 3

[0032] 1) Preparation by self-solvent method (Fe 0.8 Ti 0.2 )4Ga 0.7 In 0.3 (Te 0.8 I 0.2 )2;

[0033] 2) Fe powder, Ti powder, Ga particles, In powder, Te powder and I2 particles in a molar ratio of Fe:Ti:Ga:In:Te:I2=3.2:0.8:0.7:0.3:1.6:0.2 were mixed evenly, placed in an ampoule, and washed with Ar gas three times before vacuum sealing;

[0034] 3) Place the sealed ampoule in a muffle furnace, quickly heat it to 1000°C, and slowly cool it down at a rate of 1.5°C / h after sufficient reaction to obtain (Fe 0.8 Ti 0.2 )4Ga 0.7 In 0.3 (Te 0.8 I 0.2 )2Magnetic crystal.

[0035] Example 4

[0036] 1) Preparation by chemical vapor transport (Fe 0.8 Mn 0.2 )5(Ga 0.9 In 0.1 )2(Te 0.7 Sb 0.3 )3;

[0037] 2) Fe powder, Mn powder, Ga particles, In powder, Te powder, Sb powder and 0.2 g I2 particles in a molar ratio of Fe:Mn:Ga:In:Te:Sb=4:1:1.8:0.2:2.1:0.9 were mixed evenly, placed in a 15 cm quartz tube, and purged with Ar gas three times before vacuum sealing;

[0038] 3) Place the sealed quartz tube in a dual-temperature zone tube furnace, heat the high temperature zone and low temperature zone to 1000℃ and 750℃ respectively within 1 hour, keep them warm for 2 weeks, allow the raw materials to fully react and then cool naturally to room temperature, and obtain (Fe 0.8 Mn 0.2 )5(Ga 0.9 In 0.1 )2(Te 0.7 Sb 0.3 )3 Magnetic crystals.

[0039] Example 5

[0040] 1) Preparation by chemical vapor transport (Fe 0.7 Zn 0.3 )5(Ga 0.8 In 0.2 ) 1.5 (Te 0.9 Br 0.1 )2;

[0041] 2) Fe powder, Zn powder, Ga particles, In powder, Te powder, Br powder and 0.2 g I2 particles in a molar ratio of Fe:Zn:Ga:In:Te:Br=3.5:1.5:1.2:0.3:1.8:0.2 were mixed evenly, placed in a 15 cm quartz tube, and purged with Ar gas three times before vacuum sealing;

[0042] 3) Place the sealed quartz tube in a dual-temperature zone tube furnace, heat the high temperature zone and low temperature zone to 980℃ and 750℃ respectively within 1 hour, keep them warm for 2 weeks, allow the raw materials to fully react and then cool naturally to room temperature, and obtain (Fe 0.7 Zn 0.3 )5(Ga 0.8 In 0.2 ) 1.5 (Te 0.9 Br 0.1 )2Magnetic crystal.

[0043] Example 6

[0044] 1) Preparation by magnetron sputtering (Fe 0.8 Cr 0.2 )5(Ga 0.7 Al 0.3 )2(Te 0.6 I 0.4 )2;

[0045] 2) (Fe 0.8 Cr 0.2 )5(Ga 0.7 Al 0.3 )2(Te 0.6 I 0.4The bulk target of )2 was placed in the magnetron sputtering chamber, and Ar gas was introduced for washing. The vacuum was repeatedly evacuated three times, and the vacuum degree was 3×10 -5 mbar;

[0046] 3) Place the silicon wafer in the sample chamber and start sputtering. The sputtering power is 13W and the time is 3 minutes. Then place the sputtered silicon wafer in a tube furnace and anneal at 450℃ to obtain (Fe 0.8 Cr 0.2 )5(Ga 0.7 Al 0.3 )2(Te 0.6 I 0.4 )2Magnetic crystal.

[0047] Example 7

[0048] 1) Prepared by molecular beam epitaxy (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2;

[0049] 2) Place the sapphire substrate in the sample chamber, anneal at 600°C for 30 min, and then lower the temperature to the growth temperature of 340°C;

[0050] 3) High purity Fe, V, Ga, In, Te and Se sources were co-evaporated at 1200°C, 1900°C, 30°C, 160°C, 280°C and 220°C respectively to obtain (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 crystals.

[0051] Example 8

[0052] 1) Prepared by molecular beam epitaxy (Fe 0.9 Cr 0.1 )3Ga 0.9 Al 0.1 (Te 0.9 S 0.1 )2;

[0053] 2) Place the mica substrate in the sample chamber, anneal at 600°C for 30 min, and then lower the temperature to the growth temperature of 340°C;

[0054] 3) High purity Fe, Cr, Ga, Al, Te and S sources are co-evaporated at 1200°C, 1900°C, 30°C, 660°C, 280°C and 180°C respectively to obtain (Fe 0.9 Cr 0.1 )3Ga 0.9 Al 0.1 (Te 0.9 S 0.1 )2 crystals.

[0055] Example 9

[0056] 1) Preparation by self-solvent method (Fe 0.7 Cr 0.3 )5(Ga 0.7 Al 0.3 )3(Te 0.6 Sb 0.4 )2;

[0057] 2) Fe powder, Cr powder, Ga particles, Al particles, Te powder and Sb powder in a molar ratio of Fe:Cr:Ga:Al:Te:Sb=3.5:1.5:2.1:0.9:1.2:0.8 were mixed evenly, placed in an ampoule, and washed with Ar gas three times before vacuum sealing;

[0058] 3) Place the sealed ampoule in a muffle furnace, quickly heat it to 1000°C, and slowly cool it down at a rate of 1.5°C / h after sufficient reaction to obtain (Fe 0.7 Cr 0.3 )5(Ga 0.7 Al 0.3 )3(Te 0.6 Sb 0.4 )2Magnetic crystal.

[0059] Example 10

[0060] 1) Preparation by self-solvent method (Fe 0.9 Cu 0.1 )4(Ga 0.9 Al 0.1 )2(Te 0.8 I 0.2 )2;

[0061] 2) Fe powder, Cu powder, Ga particles, Al particles, Te powder and I2 particles in a molar ratio of Fe:Cu:Ga:Al:Te:I2=3.6:0.4:1.8:0.2:1.6:0.2 were mixed evenly, placed in an ampoule, and washed with Ar gas three times before vacuum sealing;

[0062] 3) Place the sealed ampoule in a muffle furnace, quickly heat it to 1000°C, and slowly cool it down at a rate of 1.5°C / h after sufficient reaction to obtain (Fe 0.9 Cu 0.1 )4(Ga 0.9 Al 0.1 )2(Te 0.8 I 0.2 )2Magnetic crystal.

[0063] Table 1 shows the chemical formula, preparation method, magnetic properties, Curie temperature T of Examples 1 to 10. C or Nel temperature T N The summary table of coercive force when it is ferromagnetic and antiferromagnetic shows that the new multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal described in the present invention exhibits ferromagnetism and antiferromagnetism according to the types and proportions of doping elements.

[0064] Table 1: Chemical formulas of different examples and corresponding preparation methods, magnetic properties, and Curie temperature T C or Nel temperature T N and coercivity

[0065]

[0066]

[0067] Figure 1 Yes (Fe 0.9 Cu 0.1 )3Ga 0.8 Al 0.2 (Te 0.9 Se 0.1 )2 crystal under out-of-plane magnetic field, zero-field cooling curves, field cooling curves and low-temperature hysteresis loops. 0.9 Cu 0.1 )3Ga 0.8 Al 0.2 (Te 0.9 Se 0.1 )2 has room temperature ferromagnetism and extremely large coercivity. Figure 2 Yes (Fe 0.8 Mn 0.2 )5(Ga 0.9 In 0.1 )2(Te 0.7 Sb 0.3 )3 crystal under out-of-plane magnetic field, zero-field cooling curves, field cooling curves and low-temperature hysteresis loops. 0.8 Mn 0.2 )5(Ga 0.9 In 0.1 )2(Te 0.7 Sb 0.3)3 Antiferromagnetism and higher Neel temperature of the crystal. Figure 3 Yes (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 crystal under out-of-plane magnetic field, zero-field cooling curves, field cooling curves and low-temperature hysteresis loops. 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 Antiferromagnetism and higher Neel temperature of the crystal. Figure 4 Based on (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 two-dimensional nanosheet magnetic tunnel junction device performance curve at 190K. It shows that (Fe 0.6 V 0.4 )5(Ga 0.5 In 0.5 ) 1.2 (Te 0.7 Se 0.3 )2 crystals have the potential for application in two-dimensional van der Waals antiferromagnetic spin electronics.

[0068] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Multi-element alloy two-dimensional van der Waals Ga-based magnetic crystals, It is characterized in that The magnetic crystal material is (Fe 1-x A x ) a (Ga 1-y B y ) b (Te 1-z C z ) c , wherein x, y and z are all greater than 0 and less than or equal to 0.9; a=2~6, b=0.1~2, c=0.1~5; A is Ti, V, Cr, Mn, Cu or Zn, B is Al or In, and C is S, Se, Br, I or Sb.

2. The multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal according to claim 1, It is characterized in that The multi-alloy two-dimensional van der Waals Ga-based magnetic crystal exhibits ferromagnetism below the Curie temperature or antiferromagnetism below the Neel temperature; the Curie temperature ranges from 300 to 500K, and the Neel temperature ranges from 200 to 400K.

3. The multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal according to claim 2, It is characterized in that When the multi-element alloy two-dimensional van der Waals Ga-based magnetic crystal exhibits ferromagnetism, the coercive force is 0.4-2.5T.

4. Application of the multi-alloy two-dimensional van der Waals Ga-based magnetic crystal as described in any one of claims 1 to 3 in ferromagnetic or antiferromagnetic spin electronics.

5. The use according to claim 4, It is characterized in that The application is specifically an application in a magnetic tunnel junction device, a spin-orbit torque device, a spin-transfer torque device or an electrically controlled magnetic device.

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