WO2020191527A1 - 一种磁性斯格明子材料及其制备方法和用途 - Google Patents

一种磁性斯格明子材料及其制备方法和用途 Download PDF

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WO2020191527A1
WO2020191527A1 PCT/CN2019/079282 CN2019079282W WO2020191527A1 WO 2020191527 A1 WO2020191527 A1 WO 2020191527A1 CN 2019079282 W CN2019079282 W CN 2019079282W WO 2020191527 A1 WO2020191527 A1 WO 2020191527A1
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layer
optionally
magnetic
temperature
magnetic material
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French (fr)
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王干
李彬
张猛
陈俊树
王琳晶
赵艳艳
何洪涛
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南方科技大学
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/16—Controlling or regulating
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
    • C30B25/02—Epitaxial-layer growth
    • C30B25/18—Epitaxial-layer growth characterised by the substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions
    • H10N10/852—Thermoelectric active materials comprising inorganic compositions comprising tellurium, selenium or sulfur

Definitions

  • the application belongs to the technical field of magnetic materials, and relates to a magnetic skyrmion material and a preparation method and application thereof.
  • Magnetic storage is still the current mainstream storage method. According to related theories, it can be predicted that based on the current storage mechanism, the upper limit of the storage density is several Tbit/in 2 ("Hitachi achieves nanotechnology milestone for quadrupling terabyte hard drive” (Press release). Hitachi. October 15, 2007.Retrieved 1 Sep 2011.). To further increase the storage density, it is necessary to realize smaller storage cells, that is, the size of the storage cell should be as small as a few nanometers or even the atomic level. However, at this time, a single storage cell will be affected by the superparamagnetism. Therefore, the storage of information cannot be realized, which is a great challenge to storage technology.
  • Magnetic skyrmion is a topologically stable electronic spin structure. Because of its large size span (usually from micrometer to nanometer) and flexible manipulation, it may become the core element of the next generation of information technology.
  • magnetic skyrmions can exist in a variety of material systems, such as B20 alloy, the heterostructure of metal ferromagnets and paramagnets, and magnetically doped topological insulators, the skyrmions in these material systems are either larger in size It is not conducive to control, or it needs to be generated under low temperature (less than 10K) strong magnetic field conditions. Therefore, it is particularly critical to find a material system that can allow skyrmions to exist stably at higher temperatures (close to or higher than the temperature of liquid nitrogen) and have a sufficiently small size.
  • skyrmions are generated by contacting the Bi diatomic layer with magnetic materials by doping Bi in the magnetic thin film. After Bi is doped, a diatomic layer is formed spontaneously. Because Bi atoms have strong spin-orbit interactions, the p orbitals of Bi atoms will couple with the d orbitals of Cr atoms in Cr 2 Te 3 , resulting in the formation of diatomic layers in Bi. There is a very strong Dzyaloshinskii-Moriya (DM) interaction at the junction of the layer and Cr 2 Te 3 , so skyrmions are generated near the Bi diatomic layer. However, the Bi diatomic layer generated in this way is randomly distributed in Cr 2 Te 3 on a nanometer scale, and is not continuous, so it is difficult to control its position.
  • DM Dzyaloshinskii-Moriya
  • the skyrmion size of this material is relatively large, which is not conducive to control.
  • CN108154990A discloses a method for generating non-volatile skyrmions in a multilayer film.
  • the multilayer film includes a first heavy metal layer, a ferromagnetic layer, and a second heavy metal layer stacked in sequence.
  • the first heavy metal layer and The second heavy metal layer is two different metal films.
  • the first heavy metal layer and the second heavy metal layer induce DM interaction at the interface with the ferromagnetic layer.
  • the generation method includes the following steps:
  • the purpose of this application is to provide a magnetic skyrmion material and its preparation method and application.
  • the skyrmion in the magnetic skyrmion material provided in the present application is small in size, the temperature that can exist is high, and the continuous area of the Bi diatomic layer of the magnetic skyrmion material is large.
  • the present application provides a magnetic skyrmion material.
  • the magnetic skyrmion material includes a Bi diatomic layer and a magnetic material layer on the Bi diatomic layer.
  • the position where skyrmions are generated is controllable, so this structure is also conducive to the preparation of device structures.
  • the size of skyrmions is small, with a diameter of about 4 nm; skyrmions can exist at a high temperature, and their existing temperature is above 40K.
  • the Bi diatomic layer and the magnetic material layer form a heterostructure.
  • the Bi diatomic layer is a continuous layer.
  • the magnetic material layer includes any one or a combination of at least two of a chromium tellurium magnetic material layer, a chromium oxide magnetic material layer, or a ferrite magnetic material layer, and may be a Cr 2 Te 3 magnetic material layer.
  • the thickness of the magnetic material layer is greater than 1 nm, such as 1 nm, 2 nm, 6 nm, 10 nm, 14 nm, 20 nm, 24 nm, 26 nm, 28 nm, 30 nm, or 32 nm, etc., and may be 6-32 nm.
  • the magnetic skyrmion material further includes a Bi 2 Te 3 layer, and the Bi 2 Te 3 layer and the magnetic material layer are respectively located on two sides of the Bi diatomic layer.
  • an atomic layer is obtained by the double Bi Bi 2 Te 3 layer on the surface decompose, if the Bi 2 Te 3 layer is not fully decomposed, the resulting magnetic material contains Si Geming sub-Bi 2 Te 3 layer, if Bi 2 Te When the 3 layers are completely decomposed, the Bi 2 Te 3 layer no longer appears in the skyrmion material obtained.
  • the thickness of the Bi 2 Te 3 layer is greater than 1 nm, such as 1 nm, 2 nm, 6 nm, 10 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, or 24 nm, etc., and may be 6-24 nm.
  • the magnetic skyrmion material includes a Bi 2 Te 3 layer
  • the Bi 2 Te 3 layer is located on a sapphire substrate.
  • the Bi diatomic layer is located on a sapphire substrate.
  • the present application provides a method for preparing the magnetic skyrmion material as described in the first aspect, and the method includes the following steps:
  • a Bi 2 Te 3 layer is epitaxially grown on the surface of the substrate
  • step (3) A magnetic material layer is grown on the Bi diatomic layer of step (2) to obtain the magnetic skyrmion material.
  • the Bi layer is not grown directly, but after the Bi 2 Te 3 layer is grown, the surface of the Bi 2 Te 3 layer is decomposed to produce a Bi diatomic layer by adjusting the temperature, which forms a heterogeneous layer with the magnetic material layer structure.
  • the Bi diatomic layer produced by this method has the advantages of continuous and controllable growth.
  • the epitaxial growth of the Bi 2 Te 3 layer in step (1) is performed under vacuum.
  • the vacuum degree of the vacuum is below 10 -6 mbar, such as 10 -6 mbar, 0.8 ⁇ 10 -6 mbar, 0.6 ⁇ 10 -6 mbar, 0.4 ⁇ 10 -6 mbar, 0.2 ⁇ 10 -6 mbar Or 0.1 ⁇ 10 -6 mbar, etc.
  • the substrate includes a sapphire substrate.
  • the method for epitaxially growing the Bi 2 Te 3 layer is to deposit Bi 2 Te 3 on the surface of the substrate.
  • the temperature of the epitaxially grown Bi 2 Te 3 layer is 180-230° C., such as 180° C., 190° C., 200° C., 210° C., 220° C., or 230° C., but not only Limited to the listed values, other unlisted values within this range of values also apply, and 200°C can be selected.
  • the temperature of epitaxial growth is the temperature of the substrate.
  • the growth rate of the epitaxially grown Bi 2 Te 3 layer is 0.3-0.8 nm/min, for example, 0.3 nm/min, 0.4 nm/min, 0.5 nm/min, 0.6 nm/min , 0.7nm/min or 0.8nm/min, etc., but not limited to the listed values, other unlisted values within this range of values are also applicable, and 0.5nm/min can be selected.
  • the time for the epitaxial growth of the Bi 2 Te 3 layer is 20-30 min, such as 20 min, 22 min, 24 min, 26 min, 28 min, or 30 min, etc., but it is not limited to the listed values. Other unlisted values in the value range are also applicable, and 24min can be selected.
  • the temperature adjustment in step (2) to form a Bi diatomic layer is performed under vacuum.
  • the vacuum degree of the vacuum is below 10 -6 mbar, such as 10 -6 mbar, 0.8 ⁇ 10 -6 mbar, 0.6 ⁇ 10 -6 mbar, 0.4 ⁇ 10 -6 mbar, 0.2 ⁇ 10 -6 mbar Or 0.1 ⁇ 10 -6 mbar, etc.
  • the adjusting temperature adjusts the temperature to 220-260°C, for example, 220°C, 230°C, 240°C, 250°C, or 260°C, but not limited to the listed values. Other unlisted values within the numerical range also apply.
  • the above temperature reaches the decomposition temperature of Bi 2 Te 3 , which can decompose the surface of the Bi 2 Te 3 layer to produce a Bi diatomic layer.
  • step (2) after adjusting the temperature, heat for 2s-30min from the moment when Bi 2 Te 3 decomposes, for example 2s, 1min, 5min, 15min, 18min, 20min, 24min, 28min or 30min, etc., optional For 20min.
  • the growth of the magnetic material layer in step (3) is performed under vacuum.
  • the vacuum degree of the vacuum is below 10 -6 mbar, such as 10 -6 mbar, 0.8 ⁇ 10 -6 mbar, 0.6 ⁇ 10 -6 mbar, 0.4 ⁇ 10 -6 mbar, 0.2 ⁇ 10 -6 mbar Or 0.1 ⁇ 10 -6 mbar, etc.
  • the magnetic material layer includes any one or a combination of at least two of a chromium tellurium magnetic material layer, a chromium oxide magnetic material layer or a ferrite magnetic material layer, and may be Cr 2 Te 3 magnetic material layer.
  • step (3) the method for growing the magnetic material layer is to simultaneously deposit Cr and Te onto the Bi diatomic layer in step (2).
  • step (3) the temperature at which the magnetic material layer is grown is the final temperature of step (2).
  • the growth rate of the growing magnetic material layer is 0.3-0.8nm/min, for example 0.3nm/min, 0.4nm/min, 0.5nm/min, 0.6nm/min, 0.7nm /min or 0.8nm/min, etc., but not limited to the listed values, other unlisted values within this range of values are also applicable, and 0.67 nm/min can be selected.
  • the time for growing the magnetic material layer is 20-40 min, such as 20 min, 25 min, 30 min, 35 min, or 40 min, etc., but it is not limited to the listed values, and other values within the range are not limited. The listed values are also applicable, and 30min can be selected.
  • step (1), step (2) and step (3) are all performed in a vacuum environment, the vacuum degree of step (1), step (2) and step (3) is the same .
  • the preparation of the magnetic skyrmion material is carried out in a molecular beam epitaxy device, which includes a Bi 2 Te 3 compound source, a Cr elementary source, and a Te elemental source.
  • the Bi 2 Te 3 compound source is heated to 490° C.
  • the Cr elemental source is heated to 1110° C.
  • the Te elemental source is heated to 350° C.
  • the preparation method further includes (1'): pre-heating the substrate under vacuum conditions, and lowering the temperature of the substrate after the pre-processing.
  • the heating pretreatment of the substrate is to remove the oxide layer on its surface and expose the clean substrate surface.
  • the specific vacuum degree of the vacuum condition as long as the material is not oxidized, those skilled in the art can adjust it according to the actual situation, and will not be repeated here.
  • the temperature of the heating pretreatment is 500-700°C, such as 500°C, 550°C, 600°C, 650°C, or 700°C, etc., but not limited to the listed values, Other unlisted values within this value range are also applicable, and 600°C can be selected;
  • step (1') after pretreatment, the temperature of the substrate is reduced to 180-240°C, such as 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, or 240°C, etc., but not Not limited to the listed values, other unlisted values within this range of values also apply, and 200°C can be selected.
  • 180-240°C such as 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, or 240°C, etc.
  • the method includes the following steps:
  • the sapphire substrate is pretreated at a temperature of 600°C under vacuum conditions, and then the temperature is reduced to 200°C, and the Bi 2 Te 3 compound source of the molecular beam epitaxy equipment is heated to 490°C, The Cr element source is heated to 1110°C, and the Te element source is warmed to 350°C;
  • step (1') under a vacuum degree below 10 -6 mbar, Bi 2 Te 3 is used to deposit Bi 2 Te 3 on the sapphire substrate for epitaxial growth, and the temperature of epitaxial growth is 200° C. , The time is 24min, the growth rate is 0.5nm/min;
  • step (1) Under the vacuum degree of step (1), adjust the temperature to 260°C, and hold for 20 minutes from the moment when Bi 2 Te 3 is decomposed to form a Bi diatomic layer;
  • step (2) Under the vacuum of step (2), use Cr elemental source and Te elemental source to deposit on the Bi diatomic layer described in step (2) to grow a Cr 2 Te 3 magnetic material layer, and the growth temperature is step ( 2) The final temperature, the growth time is 30 min, and the growth rate is 0.67 nm/min to obtain the magnetic skyrmion material.
  • the present application provides a use of the magnetic skyrmion material as described in the first aspect, and the magnetic skyrmion material is used in the field of information storage processing or information transmission.
  • the magnetic skyrmion material provided in this application has a small size and a high temperature at which skyrmions can exist, which is particularly suitable for the fields of information storage and processing or information transmission.
  • the diameter of the skyrmion is about 4 nm, and the temperature at which the skyrmion exists is above 40K.
  • the Bi diatomic layer has a large continuous area and forms a heterostructure with the magnetic material layer, which makes the position of skyrmion generation controllable.
  • This structure also has It is conducive to the preparation of the device structure, while the preparation method is simple, the process is short, and it is easy to carry out large-scale production.
  • Figure 1 is a schematic diagram of the structure of the magnetic skyrmion material prepared in Example 1 of this application, in which: 1-sapphire substrate, 2-Bi 2 Te 3 layer, 3-Bi diatomic layer, 4-Cr 2 Te 3 magnetic material Floor;
  • FIG. 2a is the reflective high-energy electron diffraction pattern of the sapphire substrate during the preparation process of Example 1 of the application;
  • Example 3 is a high-angle annular dark-field image characterization result of a cross section at the interface of the magnetic skyrmion material prepared in Example 1 of this application;
  • Fig. 5a is the configuration of the atomic spin dynamics calculation of the magnetic skyrmion material prepared in Example 1 of the application;
  • FIG. 5b is the M-H hysteresis loop and its derivative calculated by atomic spin dynamics of the magnetic skyrmion material prepared in Example 1 of the application;
  • Figure 5c is the skyrmion distribution of the magnetic skyrmion material prepared in Example 1 of the application when the applied magnetic field is -0.035;
  • 5d is the skyrmion distribution of the magnetic skyrmion material prepared in Example 1 of the application when the applied magnetic field is -0.075;
  • Figure 5e is the skyrmion distribution of the magnetic skyrmion material prepared in Example 1 of the application when the external magnetic field is 0.035;
  • Fig. 5f is the skyrmion distribution of the magnetic skyrmion material prepared in Example 1 of the application when the applied magnetic field is 0.075.
  • the above-mentioned magnetic field strengths are all dimensionless atomic units. To convert to Tesla, multiply by 50.
  • the magnetic skyrmion material was prepared according to the following method:
  • step (1) (2) under vacuum in step (1), the temperature was adjusted to 260 °C, from Bi 2 Te 3 decomposing start timing incubated 20min, so that the surface layer of Bi 2 Te 3 decompose to form a double atomic layer Bi;
  • step (2) Under the vacuum of step (2), open the shutter of the elemental sources of Cr and Te, and use the elemental source of Cr and Te to deposit on the Bi diatomic layer of step (2) to grow Cr 2
  • the Te 3 magnetic material layer the growth temperature is the final temperature of step (2), the growth time is 30 min, and the growth rate is 0.67 nm/min, to obtain the magnetic skyrmion material.
  • the magnetic skyrmion material prepared in this embodiment includes a Bi 2 Te 3 layer, a Bi diatomic layer on the Bi 2 Te 3 layer, and a magnetic material layer on the Bi diatomic layer, the Bi double The atomic layer is a continuous layer.
  • the Bi 2 Te 3 layer has a thickness of 12 nm
  • the Cr 2 Te 3 magnetic material layer has a thickness of 20 nm.
  • the Bi diatomic layer and the Cr 2 Te 3 magnetic material layer form a heterogeneous structure.
  • the diameter of meizi is ⁇ 4nm, the temperature at which skyrmion exists is above 40K, and the Bi 2 Te 3 layer is located on the sapphire substrate.
  • Figure 1 is a schematic diagram of the structure of the magnetic skyrmion material prepared in this embodiment. It can be seen from the figure that the magnetic skyrmion material provided in this embodiment is a sapphire substrate 1 and a Bi 2 Te 3 layer from bottom to top. 2. Bi diatomic layer 3 and Cr 2 Te 3 magnetic material layer 4, Bi diatomic layer 3 is located at the interface.
  • Fig. 2a shows the reflective high-energy electron diffraction (RHEED) pattern of the sapphire substrate during the preparation process of this embodiment, that is, the reflective high-energy electron diffraction pattern of the sapphire substrate pre-processed in step (1'). Because sapphire is an insulating substrate, there is charge accumulation on the surface, resulting in a pattern as shown in Figure 2a.
  • RHEED reflective high-energy electron diffraction
  • Figure 2b shows the reflective high-energy electron diffraction pattern of the Bi 2 Te 3 layer in the preparation process of this embodiment, that is, the reflective high-energy electron diffraction pattern obtained after the Bi 2 Te 3 film is epitaxially grown in step (1).
  • the Bi 2 Te 3 film has good crystal quality and a smooth surface.
  • Figure 2c is the reflective high-energy electron diffraction pattern of the Cr 2 Te 3 magnetic material layer in the preparation process of this embodiment, that is, the reflective high-energy electron diffraction pattern obtained after the Cr 2 Te 3 magnetic material layer is grown in step (3). It can be seen that the formed Cr 2 Te 3 film has high crystal quality and a flat surface.
  • Figure 3 is the characterization result of the high-angle annular dark field image of the cross section at the interface of the magnetic skyrmion material prepared in this embodiment.
  • the color represents the meaning: the more the darker the color, the greater the mass of the atom. The lighter color indicates the smaller the mass of the atom.
  • Both interfaces in the material system are marked with black solid lines (the interface between Bi 2 Te 3 and sapphire is not marked). From the contrast in the figure, it is obvious that there is a diatomic layer structure between Cr 2 Te 3 and Bi 2 Te 3. Judging from the contrast, this layer is the Bi diatomic layer.
  • the structures of these three layers of materials are their known structures, and their atomic configurations are drawn in the dashed box.
  • Fig. 4 Test results of variable temperature Hall resistivity of the magnetic skyrmion material prepared in this embodiment, and the temperature range is 2K-40K.
  • the arrows to the lower left and upper right respectively indicate the direction scanned by the applied magnetic field during the measurement. It can be seen from the figure that in the range of a higher magnetic field, the Hall resistivity changes linearly with the external magnetic field. This part is caused by the ordinary Hall effect. In the lower range of the applied magnetic field, an obvious hysteresis loop appears. This hysteresis loop is caused by the abnormal Hall effect. In addition to the ordinary Hall effect and anomalous Hall effect, there is a raised bulge near the coercive force field. This part of the Hall resistivity is caused by the topological Hall effect. The topological Hall effect is closely related to the magnetic field induced by magnetic skyrmions. Therefore, this is also a strong evidence for the existence of skyrmions in this material system.
  • the atomic spin dynamics calculation method is used, and the structure shown in Figure 5a is constructed based on the experimental results in this embodiment.
  • the side length of the triangle in Figure 5a is 200 times the lattice constant. From the calculated MH hysteresis loop and its differential curve (as shown in Figure 5b), it can be seen that near the coercive force field, the hysteresis loop has obvious tailing, and there is also an obvious platform on the differential curve. These are all evidences of Skyrmion's existence.
  • Figure 5c, Figure 5d, Figure 5e and Figure 5f respectively show the skyrmion distribution of the magnetic skyrmion material prepared in this embodiment when the applied magnetic field is -0.035, -0.075, 0.035 and 0.075. From the above four figures, it can be more Visually see the calculated distribution of skyrmions.
  • the Bi diatomic layer produced by the method described in this embodiment is located at the interface and forms a heterostructure with the magnetic material layer.
  • the produced Bi diatomic layer is continuous, and there is magnetism in this structure. Sky Mingzi.
  • the magnetic skyrmion material was prepared according to the following method:
  • step (1) (2) under vacuum in step (1), the temperature was adjusted to 250 deg.] C, the Bi 2 Te 3 decomposing start timing incubated 30min, so that the surface layer of Bi 2 Te 3 decompose to form a double atomic layer Bi;
  • step (2) Under the vacuum of step (2), open the shutter of the elemental sources of Cr and Te, and use the elemental source of Cr and Te to deposit on the Bi diatomic layer of step (2) to grow CrTe magnetism
  • the growth temperature is the final temperature of step (2)
  • the growth time is 20 min
  • the growth rate is 0.8 nm/min to obtain the magnetic skyrmion material.
  • the magnetic skyrmion material prepared in this embodiment includes a Bi 2 Te 3 layer, a Bi diatomic layer on the Bi 2 Te 3 layer, and a magnetic material layer on the Bi diatomic layer, the Bi double The atomic layer is a continuous layer.
  • the thickness of the Bi 2 Te 3 layer is 15 nm
  • the thickness of the CrTe magnetic material layer is 16 nm
  • the Bi diatomic layer and the CrTe magnetic material layer form a heterogeneous structure
  • the skyrmion diameter in the magnetic skyrmion material is ⁇ 4nm
  • Skyrmions exist at a temperature above 40K
  • the Bi 2 Te 3 layer is located on the sapphire substrate.
  • the magnetic skyrmion material was prepared according to the following method:
  • step (1) Under the vacuum degree of step (1), adjust the temperature to 220°C, and hold for 2 seconds from the moment when Bi 2 Te 3 is decomposed, so that the surface of the Bi 2 Te 3 layer is decomposed to form a Bi diatomic layer;
  • step (2) Under the vacuum of step (2), reduce the temperature to 100°C;
  • step (2) Open the baffle of the Cr elemental source and the oxygen/ozone micro-leakage valve, and control the vacuum degree to not exceed 10 -5 mbar, use the Cr elemental source and the oxygen/ozone source in the Bi diatomic layer described in step (2)
  • the chromium oxide magnetic material layer is grown on the upper surface, the growth temperature is the final temperature of step (3), the growth time is 40 min, and the growth rate is 0.7 nm/min to obtain the magnetic skyrmion material.
  • the magnetic skyrmion material prepared in this embodiment includes a Bi 2 Te 3 layer, a Bi diatomic layer on the Bi 2 Te 3 layer, and a magnetic material layer on the Bi diatomic layer, the Bi double The atomic layer is a continuous layer.
  • the thickness of the Bi 2 Te 3 layer is 16 nm
  • the thickness of the chromium oxide magnetic material layer is 28 nm
  • the Bi diatomic layer and the Cr 2 Te 3 magnetic material layer form a heterostructure
  • the skyrmion diameter in the magnetic skyrmion material It is ⁇ 4nm
  • the temperature at which skyrmions exist is above 40K
  • the Bi 2 Te 3 layer is located on the sapphire substrate.
  • the magnetic skyrmion material was prepared according to the following method:
  • step (1) (2) under vacuum in step (1), the temperature was adjusted to 255 deg.] C, the Bi 2 Te 3 decomposing time 22min incubation starts, so that the surface layer of Bi 2 Te 3 decompose to form a double atomic layer Bi;
  • step (3) Open the baffle of the Fe element source and the oxygen/ozone micro-leakage valve, and control the vacuum degree to not exceed 10 -5 mbar, use the Fe element source and oxygen/ozone in the Bi diatomic layer described in step (2) Deposition is performed on the upper surface to grow a ferromagnetic material layer, the growth temperature is the final temperature of step (2), the growth time is 35 min, and the growth rate is 0.7 nm/min, to obtain the magnetic skyrmion material.
  • the magnetic skyrmion material prepared in this embodiment includes a Bi 2 Te 3 layer, a Bi diatomic layer on the Bi 2 Te 3 layer, and a magnetic material layer on the Bi diatomic layer, the Bi double The atomic layer is a continuous layer.
  • the thickness of the Bi 2 Te 3 layer is 10 nm
  • the thickness of the iron oxide magnetic material layer is 24.5 nm
  • the Bi diatomic layer and the iron oxide magnetic material layer form a heterogeneous structure
  • the skyrmion diameter in the magnetic skyrmion material is ⁇ 4nm
  • the temperature at which skyrmions exist is above 40K
  • the Bi 2 Te 3 layer is located on the sapphire substrate.
  • the magnetic skyrmion material was prepared according to the following method:
  • a Bi 2 Te 3 compound source will Bi 2 Te 3 deposited epitaxially grown on the sapphire substrate, epitaxially growing
  • the temperature is 200°C, the time is 5min, and the growth rate is 0.2nm/min.
  • the baffle of the Bi 2 Te 3 source is closed to stop the growth of the Bi 2 Te 3 film;
  • step (1) Under the vacuum of step (1), adjust the temperature to 225°C, and hold for 60 minutes from the moment when Bi 2 Te 3 is decomposed, so that the Bi 2 Te 3 layer is completely decomposed to form a Bi diatomic layer;
  • step (2) Under the vacuum of step (2), open the shutter of the elemental sources of Cr and Te, and use the elemental source of Cr and Te to deposit on the Bi diatomic layer of step (2) to grow Cr 2
  • the Te 3 magnetic material layer the growth temperature is the final temperature of step (2), the growth time is 30 min, and the growth rate is 0.67 nm/min, to obtain the magnetic skyrmion material.
  • the magnetic skyrmion material prepared in this embodiment includes a Bi diatomic layer and a magnetic material layer on the Bi diatomic layer, and the Bi diatomic layer is a continuous layer.
  • the thickness of the Cr 2 Te 3 magnetic material layer is 20 nm
  • the Bi diatomic layer and the Cr 2 Te 3 magnetic material layer form a heterogeneous structure
  • the skyrmions in the magnetic skyrmions have a diameter of ⁇ 4nm
  • the temperature is above 40K
  • the Bi diatomic layer is located on the sapphire substrate.
  • the continuous area of the Bi diatomic layer in the magnetic skyrmion material provided in the present application is large, and the Bi diatomic layer and the magnetic material layer form a heterogeneous structure, which makes the skyrmion generation position controllable Yes, this structure is also conducive to the preparation of device structures.

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Abstract

一种磁性斯格明子材料及其制备方法和用途。磁性斯格明子材料包括Bi双原子层，以及位于所述Bi双原子层上的磁性材料层。制备方法包括：(1)在衬底表面外延生长Bi2Te3层；(2)调节温度形成Bi双原子层；(3)在步骤(2)所述Bi双原子层上生长磁性材料层，得到所述磁性斯格明子材料。

Description

一种磁性斯格明子材料及其制备方法和用途 技术领域
本申请属于磁性材料技术领域，涉及一种磁性斯格明子材料及其制备方法和用途。
背景技术
磁性存储仍然是当前主流的存储方式。根据相关理论可以预测，基于目前的存储机制，存储密度的上限为几个Tbit/in 2("Hitachi achieves nanotechnology milestone for quadrupling terabyte hard drive"(Press release).Hitachi.October 15,2007.Retrieved 1 Sep 2011.)。进一步提高存储密度就需要实现更小的存储单元，也就是说，存储单元的尺寸要小到几个纳米甚至原子级别，但是，此时单个存储单元将受到超顺磁极限(superparamagnetism)的影响，因此无法实现信息的存储，这对存储技术是一个极大的挑战。为了应对挑战，科技界提出利用磁性斯格明子作为下一代存储载体的技术方案，从而使得磁性斯格明子材料的研发成为了新的热点方向(Fert,Albert；Cros,Vincent；Sampaio,
Figure PCTCN2019079282-appb-000001
(2013-03-01)."Skyrmions on the track".Nature Nanotechnology.8(3):152–156.)。
磁性斯格明子是一种拓扑稳定的电子自旋结构，因其具有尺寸跨度大(通常从微米量级到纳米量级)、操控灵活等优点，有可能成为下一代信息技术的核心要素。虽然磁性斯格明子可以存在于多种材料体系，如：B20合金，金属铁磁体与顺磁体的异质结构以及磁性掺杂的拓扑绝缘体等，但是这些材料体系中的斯格明子要么尺寸较大不利于控制，要么需要在低温(小于10K)强磁场的条件下产生。因此寻找一种可以让斯格明子在较高温度下(接近或高于液氮温度)稳定存在，并且尺寸足够小的材料体系便显得尤为关键。
目前利用Bi双原子层与磁性材料接触产生斯格明子是利用在磁性薄膜中掺入Bi的方式。Bi掺入后会自发形成双原子层，由于Bi原子具有很强的自旋轨道相互作用，同时Bi原子的p轨道会与Cr 2Te 3中Cr原子的d轨道相互耦合，导致在Bi双原子层与Cr 2Te 3的交界处具有非常强的Dzyaloshinskii-Moriya(DM)相互作用，因此在Bi双原子层的附近有利于产生斯格明子。然而利用这种方式生成的Bi双原子层是以纳米级别的尺度随机分布于Cr 2Te 3中，并不连续，因此较难控制其位置。
CN105950941B公开了一种磁性斯格明子材料，其化学通式为(Mn 100-δNi δ) αGa β，其中，61.6≤α≤69，15≤δ≤50，31≤β≤38.4，α+β＝100，α、β、δ表示原子百分比含量。但是这种材料的斯格明子尺寸比较大，不利于控制。
CN108154990A公开了一种多层膜中非易失性斯格明子的生成方法，所述多层膜包括依次堆叠的第一重金属层、铁磁层和第二重金属层，所述第一重金属层和第二重金属层为两种不同的金属膜，所述第一重金属层和第二重金属层在与所述铁磁层的界面处诱导产生DM相互作用，所述生成方法包括如下步骤：
1)：对所述多层膜施加预定的磁场，其中所述磁场的强度不足以使得所述多层膜中的条状磁畴转变为斯格明子，且所述磁场的方向不平行所述多层膜的膜面；
2)：对所述多层膜施加预定的电流，使所述条状磁畴转变为斯格明子。但是这种材料的斯格明子尺寸比较大，不利于控制。
因此，开发一种斯格明子尺寸小并且斯格明子可存在温度高的磁性斯格明子材料对本领域有重要的意义。
发明内容
以下是对本文详细描述的主题的概述。本概述并非是为了限制权利要求的 保护范围。
本申请的目的在于提供一种磁性斯格明子材料及其制备方法和用途。本申请提供的磁性斯格明子材料中的斯格明子尺寸小，可存在的温度高，并且这种磁性斯格明子材料的Bi双原子层连续面积大。
为达此目的，本申请采用以下技术方案：
第一方面，本申请提供一种磁性斯格明子材料，所述磁性斯格明子材料包括Bi双原子层，以及位于所述Bi双原子层上的磁性材料层。
本申请提供的磁性斯格明子材料中，斯格明子生成的位置是可控的，因此这种结构也有利于器件结构的制备。
通过对本申请提供的磁性斯格明子材料进行输运测试，观测到了拓扑霍尔效应，并结合蒙特卡洛计算，可以确认在此种材料中斯格明子确实存在。本申请提供的磁性斯格明子材料中斯格明子尺寸小，其直径约为4nm；斯格明子可存在的温度高，其存在温度在40K以上。
以下作为本申请可选的技术方案，但不作为对本申请提供的技术方案的限制，通过以下可选的技术方案，可以更好的达到和实现本申请的技术目的和有益效果。
作为本申请可选的技术方案，所述Bi双原子层与磁性材料层形成异质结构。
可选地，所述Bi双原子层为连续的层。
可选地，所述磁性材料层包括铬碲磁性材料层、铬氧磁性材料层或铁氧磁性材料层中的任意一种或至少两种的组合，可选为Cr 2Te 3磁性材料层。
可选地，所述磁性材料层的厚度为大于1nm，例如1nm、2nm、6nm、10nm、14nm、20nm、24nm、26nm、28nm、30nm、或32nm等，可选为6-32nm。
可选地，所述磁性斯格明子材料还包括Bi 2Te 3层，所述Bi 2Te 3层与磁性材料层分别位于Bi双原子层的两侧。
本申请中，通过将Bi 2Te 3层表面分解获得Bi双原子层，如果Bi 2Te 3层没有被完全分解，则得到的磁性斯格明子材料中含有Bi 2Te 3层，如果Bi 2Te 3层完全分解，则得到的斯格明子材料中不再出现Bi 2Te 3层。
可选地，所述Bi 2Te 3层的厚度大于1nm，例如1nm、2nm、6nm、10nm、14nm、16nm、18nm、20nm、22nm或24nm等，可选为6-24nm。
可选地，当所述磁性斯格明子材料包括Bi 2Te 3层时，所述Bi 2Te 3层位于蓝宝石衬底上。
可选地，当所述磁性斯格明子材料不包括Bi 2Te 3层时，所述Bi双原子层位于蓝宝石衬底上。
第二方面，本申请提供一种如第一方面所述磁性斯格明子材料的制备方法，所述方法包括以下步骤：
(1)在衬底表面外延生长Bi 2Te 3层；
(2)调节温度形成Bi双原子层；
(3)在步骤(2)所述Bi双原子层上生长磁性材料层，得到所述磁性斯格明子材料。
该方法中，不直接生长Bi层，而是在生长了Bi 2Te 3层后，通过调节温度，使Bi 2Te 3层的表面分解产生了Bi双原子层，并和磁性材料层形成异质结构。利用这种方法生成的Bi双原子层具有连续以及生长可控等优点。
作为本申请可选的技术方案，步骤(1)所述外延生长Bi 2Te 3层在真空下进行。
可选地，所述真空的真空度在10 -6mbar以下，例如10 -6mbar、0.8×10 -6mbar、0.6×10 -6mbar、0.4×10 -6mbar、0.2×10 -6mbar或0.1×10 -6mbar等。
可选地，步骤(1)中，所述衬底包括蓝宝石衬底。
可选地，步骤(1)中，所述外延生长Bi 2Te 3层的方法为将Bi 2Te 3沉积到所述衬底表面。
可选地，步骤(1)中，所述外延生长Bi 2Te 3层的温度为180-230℃，例如180℃、190℃、200℃、210℃、220℃或230℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为200℃。这里，因为在衬底表面进行外延生长，所以外延生长的温度即为衬底的温度。
可选地，步骤(1)中，所述外延生长Bi 2Te 3层的生长速率为0.3-0.8nm/min，例如0.3nm/min、0.4nm/min、0.5nm/min、0.6nm/min、0.7nm/min或0.8nm/min等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为0.5nm/min。
可选地，步骤(1)中，所述外延生长Bi 2Te 3层的时间为20-30min，例如20min、22min、24min、26min、28min或30min等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为24min。
作为本申请可选的技术方案，步骤(2)所述调节温度形成Bi双原子层在真空下进行。
可选地，所述真空的真空度在10 -6mbar以下，例如10 -6mbar、0.8×10 -6mbar、0.6×10 -6mbar、0.4×10 -6mbar、0.2×10 -6mbar或0.1×10 -6mbar等。
可选地，步骤(2)中，所述调节温度将温度调节为220-260℃，例如220℃、230℃、240℃、250℃或260℃等，但并不仅限于所列举的数值，该数值范围内 其他未列举的数值同样适用。上述温度达到了Bi 2Te 3的分解温度，可以使Bi 2Te 3层的表面分解产生Bi双原子层。
可选地，步骤(2)中，调节温度后，从Bi 2Te 3分解的时刻开始保温2s-30min，例如2s、1min、5min、15min、18min、20min、24min、28min或30min等，可选为20min。
作为本申请可选的技术方案，步骤(3)所述生长磁性材料层在真空下进行。
可选地，所述真空的真空度在10 -6mbar以下，例如10 -6mbar、0.8×10 -6mbar、0.6×10 -6mbar、0.4×10 -6mbar、0.2×10 -6mbar或0.1×10 -6mbar等。
可选地，步骤(3)中，所述磁性材料层包括铬碲磁性材料层、铬氧磁性材料层或铁氧磁性材料层中的任意一种或至少两种的组合，可选为Cr 2Te 3磁性材料层。
可选地，步骤(3)中，所述生长磁性材料层的方法为将Cr和Te同时沉积到步骤(2)所述Bi双原子层上。
可选地，步骤(3)中，所述生长磁性材料层的温度为步骤(2)的末温。
可选地，步骤(3)中，所述生长磁性材料层的生长速率为0.3-0.8nm/min，例如0.3nm/min、0.4nm/min、0.5nm/min、0.6nm/min、0.7nm/min或0.8nm/min等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为0.67nm/min。
可选地，步骤(3)中，所述生长磁性材料层的时间为20-40min，例如20min、25min、30min、35min或40min等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为30min。
作为本申请可选的技术方案，当步骤(1)、步骤(2)和步骤(3)均在真 空环境中进行时，步骤(1)、步骤(2)和步骤(3)的真空度相同。
可选地，在分子束外延设备中进行所述磁性斯格明子材料的制备，所述分子束外延设备包含Bi 2Te 3化合物源、Cr单质源和Te单质源。
可选地，在进行步骤(1)的操作前，将Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃。
作为本申请可选的技术方案，所述制备方法还包括(1’)：在真空条件下，对衬底进行加热预处理，预处理后降低衬底的温度。
这里，对衬底进行加热预处理是为了去除其表面的氧化层，使干净的衬底表面露出。而对于真空条件的具体真空度，只要不使物料氧化即可，本领域技术人员可以根据情况自行调节，这里不再赘述。
可选地，步骤(1’)中，所述加热预处理的温度为500-700℃，例如500℃、550℃、600℃、650℃或700℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为600℃；
可选地，步骤(1’)中，预处理后降低衬底的温度至180-240℃，例如180℃、190℃、200℃、210℃、220℃、230℃或240℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用，可选为200℃。
作为本申请所述制备方法的进一步可选技术方案，所述方法包括以下步骤：
(1’)在分子束外延设备中，真空条件下将蓝宝石衬底在600℃的温度下预处理，之后降温至200℃，将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃；
(1)在步骤(1’)10 -6mbar以下的真空度下，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为200℃，时间为24min， 生长速率为0.5nm/min；
(2)在步骤(1)的真空度下，调节温度至260℃，从Bi 2Te 3分解的时刻开始保温20min，形成Bi双原子层；
(3)在步骤(2)的真空度下，用Cr单质源和Te单质源在步骤(2)所述Bi双原子层上进行沉积，生长Cr 2Te 3磁性材料层，生长温度为步骤(2)的末温，生长时间为30min，生长速率为0.67nm/min，得到所述磁性斯格明子材料。
第三方面，本申请提供一种如第一方面所述磁性斯格明子材料的用途，所述磁性斯格明子材料用于信息存储处理或信息传输的领域。
与相关技术相比，本申请具有以下有益效果：
(1)本申请提供的磁性斯格明子材料中斯格明子尺寸小，斯格明子可存在的温度高，特别适用于信息存储处理或信息传输的领域。本申请提供的磁性斯格明子材料中，斯格明子的直径约为4nm，斯格明子存在的温度为40K以上。
(2)本申请提供的磁性斯格明子材料中Bi双原子层连续面积大，并和磁性材料层形成异质结构，这就使得斯格明子生成的位置是可控的，这种结构也有利于器件结构的制备，同时制备方法简单，流程短，易于进行规模化生产。
在阅读并理解了详细描述和附图后，可以明白其他方面。
附图说明
图1为本申请实施例1制备的磁性斯格明子材料的结构示意图，其中，1-蓝宝石衬底，2-Bi 2Te 3层，3-Bi双原子层，4-Cr 2Te 3磁性材料层；
图2a为本申请实施例1制备过程中蓝宝石衬底的反射式高能电子衍射图案；
图2b为本申请实施例1制备过程中Bi 2Te 3层的反射式高能电子衍射图案；
图2c为本申请实施例1制备过程中Cr 2Te 3磁性材料层的反射式高能电子衍射图案；
图3为本申请实施例1制备的磁性斯格明子材料界面处横截面的高角度环形暗场象表征结果；
图4为本申请实施例1制备的磁性斯格明子材料的变温度霍尔电阻率测试结果；
图5a为本申请实施例1制备的磁性斯格明子材料的原子自旋动力学计算的构型；
图5b为本申请实施例1制备的磁性斯格明子材料的原子自旋动力学计算得到的M-H磁滞回线及其微分；
图5c为本申请实施例1制备的磁性斯格明子材料在外加磁场为-0.035时的斯格明子分布情况；
图5d为本申请实施例1制备的磁性斯格明子材料在外加磁场为-0.075时的斯格明子分布情况；
图5e为本申请实施例1制备的磁性斯格明子材料在外加磁场为0.035时的斯格明子分布情况；
图5f为本申请实施例1制备的磁性斯格明子材料在外加磁场为0.075时的斯格明子分布情况。
以上提到的磁场强度均为无量纲的原子单位制，若要转换成特斯拉，需乘以50。
具体实施方式
为更好地说明本申请，便于理解本申请的技术方案，下面对本申请进一步 详细说明。但下述的实施例仅仅是本申请的简易例子，并不代表或限制本申请的权利保护范围，本申请保护范围以权利要求书为准。
以下为本申请典型但非限制性实施例：
实施例1
本实施按照如下方法制备磁性斯格明子材料：
(1’)将蓝宝石衬底放入分子束外延设备的样品台上，并将气压调节为真空，在600℃的温度下预处理，之后降温至200℃，并稳定10分钟。将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃；
(1)在10 -6mbar以下的真空度下，打开Bi 2Te 3化合物源的挡板，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为200℃，时间为24min，生长速率为0.5nm/min，之后关闭Bi 2Te 3源的挡板，停止Bi 2Te 3薄膜的生长；
(2)在步骤(1)的真空度下，调节温度至260℃，从Bi 2Te 3分解的时刻开始保温20min，使Bi 2Te 3层表面分解形成Bi双原子层；
(3)在步骤(2)的真空度下，打开Cr和Te的单质源的挡板，用Cr单质源和Te单质源在步骤(2)所述Bi双原子层上进行沉积，生长Cr 2Te 3磁性材料层，生长温度为步骤(2)的末温，生长时间为30min，生长速率为0.67nm/min，得到所述磁性斯格明子材料。
本实施例制备的磁性斯格明子材料包括Bi 2Te 3层，位于所述Bi 2Te 3层上的Bi双原子层，以及位于所述Bi双原子层上的磁性材料层，所述Bi双原子层为连续的层。Bi 2Te 3层的厚度为12nm，Cr 2Te 3磁性材料层的厚度为20nm，Bi双 原子层与Cr 2Te 3磁性材料层形成异质结构，所述磁性斯格明子材料中的斯格明子直径为～4nm，斯格明子存在的温度为40K以上，所述Bi 2Te 3层位于蓝宝石衬底上。
图1为本实施例制备的磁性斯格明子材料的结构示意图，由该图可以看出，本实施例提供的磁性斯格明子材料从下到上依次为蓝宝石衬底1、Bi 2Te 3层2、Bi双原子层3和Cr 2Te 3磁性材料层4，Bi双原子层3位于界面处。
图2a为本实施例制备过程中蓝宝石衬底的反射式高能电子衍射(RHEED)图案，即步骤(1’)预处理后的蓝宝石衬底的反射式高能电子衍射图案。因为蓝宝石为绝缘衬底，因此表面有电荷积累，导致出现如图2a所示图案。
图2b为本实施例制备过程中Bi 2Te 3层的反射式高能电子衍射图案，即步骤(1)外延生长出Bi 2Te 3薄膜后得到的反射式高能电子衍射图案，从该图可以看出Bi 2Te 3薄膜具有很好的晶体质量，并且表面平整。
图2c为本实施例制备过程中Cr 2Te 3磁性材料层的反射式高能电子衍射图案，即步骤(3)生长Cr 2Te 3磁性材料层后得到的反射式高能电子衍射图案，从该图可以看出生成的Cr 2Te 3薄膜具有很高的晶体质量，并且表面平整。
图3为本实施例制备的磁性斯格明子材料界面处横截面的高角度环形暗场象表征结果，其中的颜色所代表的含义为：越偏向于深色，表明原子的质量越大，越偏向浅色，表明原子的质量越小。材料体系中的两个界面均以黑色实线标出(Bi 2Te 3与蓝宝石的界面并未标出)。从图中的衬度可以明显的看到，在Cr 2Te 3与Bi 2Te 3中间有一个双原子层的结构，从衬度上来判断，这一层便是Bi双原子层。这三层材料的结构均为其已知的结构，其原子构形在虚线的方框内画出。
图4本实施例制备的磁性斯格明子材料的变温度霍尔电阻率测试结果，温 度范围为2K-40K。其中向左下和向右上的箭头分别表示在测量过程中外加磁场所扫描的方向。从图中可以看出，在较高磁场的范围，霍尔电阻率随外加磁场呈线性变化。这一部分是由于普通的霍尔效应所导致的。在较低的外加磁场的范围，出现了明显的磁滞回线。这一磁滞回线是由于反常霍尔效应所造成的。除了普通的霍尔效应和反常霍尔效应之外，在矫顽力场附近还有一个凸起的鼓包。这一部分霍尔电阻率便是由拓扑霍尔效应所造成的。而拓扑霍尔效应则与磁性斯格明子所诱导出的磁场密切相关，因此，这也是斯格明子在这一材料体系中存在的强有力的证据。
为了进一步验证磁性斯格明子在本实施例的磁性斯格明子材料中存在的稳定性，采用了原子自旋动力学计算方法，以本实施例中的实验结果为基础构建了如图5a所示的构型，并模拟了在外加磁场的情况下，磁滞回线以及斯格明子分布的情况。图5a三角形的边长为晶格常数的200倍。从计算得到的M-H磁滞回线及其微分曲线(如图5b所示)可以看到在矫顽力场附近，磁滞回线有明显的拖尾，同时在微分曲线上也有明显的平台，这些也都是斯格明子存在的证据。图5c、图5d、图5e和图5f分别为本实施例制备的磁性斯格明子材料在外加磁场为-0.035、-0.075、0.035和0.075时的斯格明子分布情况，从上述四图可以更直观地看到计算得到的斯格明子的分布。
综上所述，本实施例所阐述的方法所生成的Bi双原子层位于界面处，并和磁性材料层形成异质结构，生成的Bi双原子层是连续的，并且这种结构中存在磁性斯格明子。
实施例2
本实施按照如下方法制备磁性斯格明子材料：
(1’)将蓝宝石衬底放入分子束外延设备的样品台上，并将气压调节为真空，在500℃的温度下预处理，之后降温至180℃，并稳定10分钟。将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至300℃；
(1)在10 -6mbar以下的真空度下，打开Bi 2Te 3化合物源的挡板，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为180℃，时间为25min，生长速率为0.6nm/min，之后关闭Bi 2Te 3源的挡板，停止Bi 2Te 3薄膜的生长；
(2)在步骤(1)的真空度下，调节温度至250℃，从Bi 2Te 3分解的时刻开始保温30min，使Bi 2Te 3层表面分解形成Bi双原子层；
(3)在步骤(2)的真空度下，打开Cr和Te的单质源的挡板，用Cr单质源和Te单质源在步骤(2)所述Bi双原子层上进行沉积，生长CrTe磁性材料层，生长温度为步骤(2)的末温，生长时间为20min，生长速率为0.8nm/min，得到所述磁性斯格明子材料。
本实施例制备的磁性斯格明子材料包括Bi 2Te 3层，位于所述Bi 2Te 3层上的Bi双原子层，以及位于所述Bi双原子层上的磁性材料层，所述Bi双原子层为连续的层。Bi 2Te 3层的厚度为15nm，CrTe磁性材料层的厚度为16nm，Bi双原子层与CrTe磁性材料层形成异质结构，所述磁性斯格明子材料中的斯格明子直径为～4nm，斯格明子存在的温度为40K以上，所述Bi 2Te 3层位于蓝宝石衬底上。
实施例3
本实施按照如下方法制备磁性斯格明子材料：
(1’)将蓝宝石衬底放入分子束外延设备的样品台上，并将气压调节为真空，在700℃的温度下预处理，之后降温至230℃，并稳定10分钟。将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，同时该设备需具备通入微量氧气或臭氧的功能；
(1)在10 -6mbar以下的真空度下，打开Bi 2Te 3化合物源的挡板，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为230℃，时间为40min，生长速率为0.4nm/min，之后关闭Bi 2Te 3源的挡板，停止Bi 2Te 3薄膜的生长；
(2)在步骤(1)的真空度下，调节温度至220℃，从Bi 2Te 3分解的时刻开始保温2s，使Bi 2Te 3层表面分解形成Bi双原子层；
(3)在步骤(2)的真空度下，将温度降至100℃；
(4)打开Cr单质源的挡板和氧气/臭氧的微漏阀，并控制真空度不超过10 -5mbar，用Cr单质源和氧气/臭氧源在步骤(2)所述Bi双原子层上进行沉积，生长氧化铬磁性材料层，生长温度为步骤(3)的末温，生长时间为40min，生长速率为0.7nm/min，得到所述磁性斯格明子材料。
本实施例制备的磁性斯格明子材料包括Bi 2Te 3层，位于所述Bi 2Te 3层上的Bi双原子层，以及位于所述Bi双原子层上的磁性材料层，所述Bi双原子层为连续的层。Bi 2Te 3层的厚度为16nm，氧化铬磁性材料层的厚度为28nm，Bi双原子层与Cr 2Te 3磁性材料层形成异质结构，所述磁性斯格明子材料中的斯格明子直径为～4nm，斯格明子存在的温度为40K以上，所述Bi 2Te 3层位于蓝宝石衬底上。
实施例4
本实施按照如下方法制备磁性斯格明子材料：
(1’)将蓝宝石衬底放入分子束外延设备的样品台上，并将气压调节为真空，在650℃的温度下预处理，之后降温至200℃，并稳定10分钟。将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Fe单质源升温至1200℃，同时该设备需具备通入微量氧气或臭氧的功能；
(1)在10 -6mbar以下的真空度下，打开Bi 2Te 3化合物源的挡板，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为200℃，时间为20min，生长速率为0.5nm/min，之后关闭Bi 2Te 3源的挡板，停止Bi 2Te 3薄膜的生长；
(2)在步骤(1)的真空度下，调节温度至255℃，从Bi 2Te 3分解的时刻开始保温22min，使Bi 2Te 3层表面分解形成Bi双原子层；
(3)打开Fe单质源的挡板和氧气/臭氧的微漏阀，并控制真空度不超过10 -5mbar，，用Fe单质源和氧气/臭氧在步骤(2)所述Bi双原子层上进行沉积，生长氧化铁磁性材料层，生长温度为步骤(2)的末温，生长时间为35min，生长速率为0.7nm/min，得到所述磁性斯格明子材料。
本实施例制备的磁性斯格明子材料包括Bi 2Te 3层，位于所述Bi 2Te 3层上的Bi双原子层，以及位于所述Bi双原子层上的磁性材料层，所述Bi双原子层为连续的层。Bi 2Te 3层的厚度为10nm，氧化铁磁性材料层的厚度为24.5nm，Bi双原子层与氧化铁磁性材料层形成异质结构，所述磁性斯格明子材料中的斯格明子直径为～4nm，斯格明子存在的温度为40K以上，所述Bi 2Te 3层位于蓝宝石衬底上。
实施例5
本实施按照如下方法制备磁性斯格明子材料：
(1’)将蓝宝石衬底放入分子束外延设备的样品台上，并将气压调节为真空，在600℃的温度下预处理，之后降温至200℃，并稳定10分钟。将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃；
(1)在10 -6mbar以下的真空度下，打开Bi 2Te 3化合物源的挡板，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上外延生长，外延生长的温度为200℃，时间为5min，生长速率为0.2nm/min，之后关闭Bi 2Te 3源的挡板，停止Bi 2Te 3薄膜的生长；
(2)在步骤(1)的真空度下，调节温度至225℃，从Bi 2Te 3分解的时刻开始保温60min，使Bi 2Te 3层完全分解形成Bi双原子层；
(3)在步骤(2)的真空度下，打开Cr和Te的单质源的挡板，用Cr单质源和Te单质源在步骤(2)所述Bi双原子层上进行沉积，生长Cr 2Te 3磁性材料层，生长温度为步骤(2)的末温，生长时间为30min，生长速率为0.67nm/min，得到所述磁性斯格明子材料。
本实施例制备的磁性斯格明子材料包括Bi双原子层，以及位于所述Bi双原子层上的磁性材料层，所述Bi双原子层为连续的层。Cr 2Te 3磁性材料层的厚度为20nm，Bi双原子层与Cr 2Te 3磁性材料层形成异质结构，所述磁性斯格明子材料中的斯格明子直径为～4nm，斯格明子存在的温度为40K以上，所述Bi双原子层位于蓝宝石衬底上。
综合上述实施例可知，本申请提供的磁性斯格明子材料中Bi双原子层连续面积大，并且Bi双原子层和磁性材料层形成异质结构，这就使得斯格明子生成 的位置是可控的，这种结构也有利于器件结构的制备。
申请人声明，本申请通过上述实施例来说明本申请的详细工艺设备和工艺流程，但本申请并不局限于上述详细工艺设备和工艺流程，即不意味着本申请必须依赖上述详细工艺设备和工艺流程才能实施。

Claims (14)

  1. 一种磁性斯格明子材料，其中，所述磁性斯格明子材料包括Bi双原子层，以及位于所述Bi双原子层上的磁性材料层。
  2. 根据权利要求1所述的磁性斯格明子材料，其中，所述Bi双原子层与磁性材料层形成异质结构。
  3. 根据权利要求1或2所述的磁性斯格明子材料，其中，所述Bi双原子层为连续的层。
  4. 根据权利要求1-3任一项所述的磁性斯格明子材料，其中，所述磁性材料层包括铬碲磁性材料层、铬氧磁性材料层或铁氧磁性材料层中的任意一种或至少两种的组合，可选为Cr 2Te 3磁性材料层；
    可选地，所述磁性材料层的厚度为大于1nm，可选为6-32nm。
  5. 根据权利要求1-4任一项所述的磁性斯格明子材料，其中，所述磁性斯格明子材料还包括Bi 2Te 3层，所述Bi 2Te 3层与磁性材料层分别位于Bi双原子层的两侧；
    可选地，所述Bi 2Te 3层的厚度为大于1nm，可选为6-24nm；
    可选地，当所述磁性斯格明子材料包括Bi 2Te 3层时，所述Bi 2Te 3层位于蓝宝石衬底上；
    可选地，当所述磁性斯格明子材料不包括Bi 2Te 3层时，所述Bi双原子层位于蓝宝石衬底上。
  6. 一种如权利要求1-5任一项所述磁性斯格明子材料的制备方法，其中，所述方法包括以下步骤：
    (1)在衬底表面外延生长Bi 2Te 3层；
    (2)调节温度形成Bi双原子层；
    (3)在步骤(2)所述Bi双原子层上生长磁性材料层，得到所述磁性斯格明子材料。
  7. 根据权利要求6所述的方法，其中，步骤(2)中，所述调节温度将温度调节为220-260℃；
    可选地，步骤(2)所述调节温度形成Bi双原子层在真空下进行；
    可选地，所述真空的真空度在10 -6mbar以下。
  8. 根据权利要求6或7所述的方法，其中，步骤(2)中，步骤(2)中，调节温度后，从Bi 2Te 3分解的时刻开始保温2s-30min，可选为20min。
  9. 根据权利要求6-8任一项所述的方法，其中，步骤(1)所述外延生长Bi 2Te 3层在真空下进行；
    可选地，所述真空的真空度在10 -6mbar以下；
    可选地，步骤(1)中，所述衬底包括蓝宝石衬底；
    可选地，步骤(1)中，所述外延生长Bi 2Te 3层的方法为将Bi 2Te 3沉积到所述衬底表面；
    可选地，步骤(1)中，所述外延生长Bi 2Te 3层的温度为180-230℃，可选为200℃；
    可选地，步骤(1)中，所述外延生长Bi 2Te 3层的生长速率为0.3-0.8nm/min，可选为0.5nm/min；
    可选地，步骤(1)中，所述外延生长Bi 2Te 3层的时间为20-30min，可选为24min。
  10. 根据权利要求6-8任一项所述的制备方法，其中，步骤(3)所述生长磁性材料层在真空下进行；
    可选地，所述真空的真空度在10 -6mbar以下；
    可选地，步骤(3)中，所述磁性材料层包括铬碲磁性材料层、铬氧磁性材料层或铁氧磁性材料层中的任意一种或至少两种的组合，可选为Cr 2Te 3磁性材料层；
    可选地，步骤(3)中，所述生长磁性材料层的方法为将Cr和Te同时沉积到步骤(2)所述Bi双原子层上；
    可选地，步骤(3)中，所述生长磁性材料层的温度为步骤(2)的末温；
    可选地，步骤(3)中，所述生长磁性材料层的生长速率为0.3-0.8nm/min，可选为0.67nm/min；
    可选地，步骤(3)中，所述生长磁性材料层的时间为20-40min，可选为30min。
  11. 根据权利要求6-10任一项所述的制备方法，其中，当步骤(1)、步骤(2)和步骤(3)均在真空环境中进行时，步骤(1)、步骤(2)和步骤(3)的真空度相同；
    可选地，在分子束外延设备中进行所述磁性斯格明子材料的制备，所述分子束外延设备包含Bi 2Te 3化合物源、Cr单质源和Te单质源；
    可选地，在进行步骤(1)的操作前，将Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃。
  12. 根据权利要求6-11任一项所述的制备方法，其中，所述制备方法还包括(1’)：在真空条件下，对衬底进行加热预处理，预处理后降低衬底的温度；
    可选地，步骤(1’)中，所述加热预处理的温度为500-700℃，可选为600℃；
    可选地，步骤(1’)中，预处理后降低衬底的温度至180-240℃，可选为200℃。
  13. 根据权利要求6-12任一项所述的制备方法，其中，所述方法包括以下步骤：
    (1’)在分子束外延设备中，真空条件下将蓝宝石衬底在600℃的温度下预处理，之后降温至200℃，将分子束外延设备的Bi 2Te 3化合物源升温至490℃，Cr单质源升温至1110℃，Te单质源升温至350℃；
    (1)在10 -6mbar以下的真空度下，用Bi 2Te 3化合物源将Bi 2Te 3沉积到所述蓝宝石衬底上进行外延生长，外延生长的温度为200℃，生长速率为0.5nm/min，生长时间为24min；
    (2)在步骤(1)的真空度下，调节温度至260℃，从Bi 2Te 3分解的时刻开始保温20min，形成Bi双原子层；
    (3)在步骤(2)的真空度下，用Cr单质源和Te单质源在步骤(2)所述Bi双原子层上进行沉积，生长Cr 2Te 3磁性材料层，生长温度为步骤(2)的末温，生长速率为0.67nm/min，生长时间为30min，得到所述磁性斯格明子材料。
  14. 一种如权利要求1-5任一项所述磁性斯格明子材料的用途，其中，所述磁性斯格明子材料用于信息存储处理或信息传输的领域。
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