A nanocrystalline magnetic material and a preparation method thereof

Abstract

The present invention discloses a nanocrystalline magnetic material and a preparation method thereof. The material is a magnetic Nb3VSe6 crystal, which contains three elements, namely Nb, V, and Se. The stoichiometric molar ratio of the three elements is 3:1:6. The crystal has a centrosymmetrically broken hexagonal layered structure, and its space group is P6322. The V atoms are inserted between two 2H-NbS2 hexagonal layers, with lattice constants a = b = 5.738 Å and c = 12.018 Å. The magnetism in the material is mainly contributed by trivalent Cr ions, with a magnetic moment of 3 μB and a local electron spin S = 3 / 2, while the conduction electrons originate from the unfilled band of Nb atoms. Due to its unique crystal structure and electronic properties, the material exhibits potential application value in multiple fields, especially in high-frequency devices, spintronic components, and magnetic dampers, etc. The Nb3VSe6 single crystal is relatively stable in air, which is a great advantage for practical applications.

Description

Technical Field

[0001] The present invention relates to the field of new material science and technology, and particularly to a nanocrystal magnetic material and a preparation method thereof. Background Art

[0002] With the development of science and technology, the demand for new functional materials is increasing day by day. Among numerous new materials, compounds with special physical properties have received extensive attention due to their potential applications in fields such as sensors, electronic devices, and magnetic devices. In particular, those materials that exhibit the characteristic of resistance changing with temperature within a specific temperature range are one of the research hotspots. In addition, materials with both magnetism are highly regarded for their application prospects in data storage, magnetic resonance imaging (MRI), etc.

[0003] Nb3VSe6 is a new compound, and its unique resistance-temperature characteristic and magnetism enable it to show potential application value in multiple fields. However, the current research on this compound is still in its initial stage, lacking systematic and in-depth research reports. Therefore, developing an efficient and stable method to synthesize this compound and conducting a detailed study on its physical and chemical properties are of great significance for promoting the technological progress in related fields.

[0004] In the field of low-dimensional magnetic materials, especially those materials that can exhibit ferromagnetic order in two dimensions or lower dimensions, such as Cr2Ge2Te6, Fe3GeTe2, and Cr3VS6, their discovery and development have not only greatly expanded our understanding of the essence of material magnetism but also brought revolutionary changes to the field of spintronics. The characteristics of these materials enable scientists to precisely control the spin state of electrons at the nanoscale and even atomic level, which is crucial for the development of new spintronic devices. The potential applications of these devices include, but are not limited to, future computer chips, data storage systems, sensors, and quantum computing, etc., and they are expected to bring higher efficiency, lower energy consumption, and smaller size.

[0005] It is worth noting that among these low-dimensional magnetic materials, the resistance behavior of a specific material shows unique properties with the change of temperature. For example, there is a material whose resistance increases with the increase of temperature in the temperature range of 2 - 25K; and in the temperature range of 25 - 300K, this trend continues, that is, the resistance still increases with the increase of temperature. 25K is considered a transition temperature point of this material, near which the resistance behavior of the material changes significantly. This special resistance-temperature relationship may be related to the magnetic transition inside the material and is of great significance for deeply understanding the magnetic and electrical transport properties of the material. Such research not only helps us better understand the basic physical mechanism of low-dimensional magnetic materials but also provides important guidance for the design and optimization of high-performance spintronic devices. Summary of the Invention

[0006] The object of the present invention is to provide a nanocrystal magnetic material and a preparation method thereof.

[0007] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0008] A Nb3VSe6 low-dimensional magnetic material and its resistance characteristics at low temperature, this material is a magnetic Nb3VSe6 crystal, containing three elements, namely Nb, V, and Se, and the stoichiometric molar ratio of the three elements is 3:1:6. Specifically, the atomic percentage of Nb is 30.83404%, the atomic percentage of V is 9.84943%, and the atomic percentage of Se is 59.31653%.

[0009] This crystal has a centrosymmetrically broken hexagonal layered structure, its space group is P6322, V atoms are inserted between two 2H-NbS2 hexagonal layers, and the lattice constant The magnetism in the material is mainly contributed by trivalent V ions, with a magnetic moment of 3μB and a local electron spin S = 3 / 2, while the conduction electrons originate from the unfilled band of Nb atoms. The Nb3VSe6 single crystal has a high-frequency response: due to the strong exchange interaction between the internal magnetic moments of this material, it can support magnetic oscillations at very high frequencies, much faster than ferromagnetic materials. This is particularly valuable for high-speed data processing and communication technologies.

[0010] The Nb3VSe6 single crystal is a material that exhibits unique resistance-temperature characteristics in the temperature range from low temperature to room temperature. Specifically, in the temperature range of 2 - 25K, as the temperature increases, the resistance of Nb3VSe6 gradually increases; this trend continues in the temperature range of 25 - 300K, indicating that within the entire temperature measurement range, the resistance increases with the increase in temperature. 25K is considered a key transition temperature point for Nb3VSe6, near which the resistance behavior of the material changes significantly, which may be related to the transition of its internal magnetic state.

[0011] In addition to its unique resistance-temperature characteristics, single-crystalline Nb3VSe6 exhibits low magnetic hysteresis loss during magnetic field reversal. This means that when changing the magnetization direction, it does not need to overcome a large coercive force. This property makes Nb3VSe6 particularly suitable for application scenarios that require frequent switching of magnetic states, such as specific types of sensors or read / write heads. Furthermore, the unique properties of single-crystalline Nb3VSe6 material make it an ideal platform for studying spintronic phenomena. In particular, the spin Hall effect at its interface can effectively manipulate the magnetic moments in antiferromagnetic materials, which is crucial for the development of a new generation of spintronic devices. Although antiferromagnetic materials are not traditionally used directly for information storage because their magnetization states are not easily detected and modified by external magnetic fields, recent research has shown that efficient data storage solutions can also be achieved by precisely controlling the movement of magnetic domain walls in antiferromagnetic materials or by utilizing antiferromagnetic resonance and other methods. Therefore, single-crystalline Nb3VSe6 has attracted attention not only for its low magnetic hysteresis loss and unique resistance-temperature characteristics but also shows great potential in the field of information storage, opening up new paths for the development of future spintronic technologies and data storage technologies. The single-crystalline materials synthesized by chemical vapor transport method require a sealed high-temperature furnace and precise temperature control. Therefore, the equipment is relatively complex and the cost is relatively high. And it often requires a long time, which affects the production efficiency. Moreover, the success of single crystals largely depends on the fine control of growth conditions, including temperature gradient, types and dosages of transport agents, etc., which requires high experience and skills of experimental personnel.

[0012] Although selenium, as an important non-metal element, shows great application potential in many fields such as optoelectronic materials, catalysts, biopharmaceuticals, etc., the research on the formation mechanism of selenium-containing single crystals is relatively scarce. Currently, the reports on the artificial synthesis of selenium-containing single crystals and their crystal structure data in the academic and industrial communities are extremely limited. This gap in research limits our understanding of the deep properties of selenium-based materials and also hinders the wide application of these materials in high-tech fields.

[0013] Selenium-containing single crystals play an irreplaceable role in optoelectronic conversion, sensing technology, energy storage, etc. due to their unique physical and chemical properties. However, due to the special properties of selenium itself, such as high reactivity, volatility, etc., the preparation process of selenium-containing single crystals is full of challenges. In addition, the diversity of selenium-based compounds also increases the complexity of crystal growth, resulting in slow progress in related research. Against this background, it becomes particularly important to explore effective methods for artificially synthesizing selenium-containing single crystals.

[0014] By systematically studying the formation mechanism of selenium-containing single crystals, not only can the gaps in existing research be filled, but also a solid theoretical basis can be provided for subsequent material design and applications. At the same time, comprehensively and meticulously characterizing the crystal structure of selenium-containing single crystals can reveal the internal atomic arrangement rules, thereby guiding the design of new functional materials.

[0015] Exploring and mastering the method of artificially synthesizing selenium-containing single crystals is not only the key to further deepening the understanding of the crystal structure characteristics of this type of material, but also the basis for understanding its formation mechanism. This not only helps to promote the development of related science and technology, but also will facilitate the practical application of selenium-containing single crystals in more high-tech fields, contributing to future scientific and technological progress and social development. Therefore, strengthening research in this field has important scientific value and practical significance.

[0016] Nb3VSe6 single crystals have excellent air stability and usually exhibit antiferromagnetism, but can also show ferromagnetism under specific conditions. When made in the form of nanosheets, it retains these favorable properties, and due to its nanoscale size, it can also exhibit some quantum confinement effects, which may enhance its magnetic performance. Therefore, Nb3VSe6 single crystal nanosheets have broad application potential in the preparation of high-performance and low-cost magnetic devices, showing broad application prospects in the fields of microelectronics, spintronics, and sensors. With the development of science and technology, the emergence of Nb3VSe6 has led to the emergence of new technologies and new applications for more antiferromagnetic materials. This is of great significance for future quantum computing.

[0017] The synthesis of a Nb3VSe6 low-dimensional magnetic material and its resistance characteristics at low temperatures includes the following steps:

[0018] Step 1: Uniformly mix the raw material powders of Nb, V, and Se with a purity greater than 99.9% in a test tube according to three elements: Nb: 0.2787 g, V: 0.0509 g, Se: 0.1924 g.

[0019] Step 2: Vacuum encapsulate together with a small amount and appropriate amount of tellurium tetrachloride as a transport agent in a quartz tube with a diameter of 10 mm and a length of 200 mm.

[0020] Step 3: Place the encapsulated sample in a two-zone tube furnace, set the temperature to first rise to 950 °C at a rate of 3.0 °C / min, hold for 24 h, then rise to 1050 °C at a rate of 0.55 °C / min and hold for 168 h. After the high-temperature vacuum reaction is completed, take out the obtained sample to obtain high-quality magnetic Nb3VSe6 single crystals.

[0021] The present invention has the following beneficial effects: The Nb3VSe6 single crystal is a low-dimensional material with unique physical properties and belongs to the family of transition metal trichalcogenides (TMTCs). It fills the gap in existing research and can also provide a solid theoretical basis for subsequent material design and applications. At the same time, due to its unique crystal structure and electronic properties, this material exhibits potential application value in multiple fields, especially in high-frequency devices, spintronic components, and magnetic dampers. The Nb3VSe6 single crystal is relatively stable in air, which is a great advantage for practical applications. Description of the Drawings

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below.

[0023] Figure 1 : XRD measured by the new material Nb3VSe6 instrument.

[0024] Figure 2 : Element analysis diagram of the new material Nb3VSe6.

[0025] Figure 3 : Selected area electron diffraction pattern of the new material Nb3VSe6.

[0026] Figure 4 : High-resolution lattice diagram of the new material Nb3VSe6.

[0027] Figure 5 : Magnetic field strength test diagram of the new material Nb3VSe6.

[0028] Figure 6 : Resistance-temperature (R-T) curve of the new material Nb3VSe6. Detailed Embodiments

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0030] A nanocrystalline magnetic material, which is a magnetic Nb3VSe6 crystal and contains three elements, namely Nb, V, and Se. The stoichiometric molar ratio of the three elements is 3:1:6. Specifically, the atomic percentage of Nb is 30.83404%, the atomic percentage of V is 9.84943%, and the atomic percentage of Se is 59.31653%. The crystal has a centrosymmetrically broken hexagonal layered structure, and its space group is P6322. The V atoms are inserted between two 2H-NbS2 hexagonal layers, and the lattice constant The magnetism in the crystal is mainly contributed by trivalent V ions, with a magnetic moment of 3μB and a local electron spin S = 3 / 2. The conduction electrons come from the unfilled band of Nb atoms.

[0031] A method for preparing a nanocrystal magnetic material, comprising the following steps:

[0032] Step 1: Mix the raw materials of Nb, V, and Se with a purity greater than 99.9% in accordance with three elements: Nb: 0.2787 g, V: 0.0509 g, and Se: 0.1924 g.

[0033] Step 2: Vacuum encapsulate them together with a small amount and appropriate amount of tellurium tetrachloride as a transport agent in a quartz tube with a diameter of 10 mm and a length of 200 mm.

[0034] Step 3: Place the encapsulated sample in a two-zone tube furnace. The temperature is set to first rise to 950 °C at a rate of 3.0 °C / min and hold for 24 h, then rise to 1050 °C at a rate of 0.55 °C / min and hold for 168 h. After the high-temperature vacuum reaction is completed, take out the obtained sample to obtain high-quality magnetic Nb3VSe6 single crystals.

[0035] Figure 2 The EDS spectrum of the Nb3VSe6 single crystal sample is shown, and the surface morphology of the sample is obtained by SEM. It can be known from the EDS spectrum that the chemical composition ratio of the prepared sample is Nb:V:S = 30.83:9.85:59.32, which is very close to the expected ratio of the compound. The regular morphology and correct element composition ratio prove that the preparation method we adopted is very reliable.

[0036] This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. A preparation method of a nanocrystal magnetic material, characterized in that: The material is a magnetic Nb3VSe6 crystal, containing three elements, namely Nb, V and Se, and the stoichiometric molar ratio of the three elements is 3:1:6; The preparation method of the magnetic Nb3VSe6 crystal comprises the following steps: Step 1: Mix the raw materials of Nb, V, and Se with a purity greater than 99.9% according to the three elements of Nb: 0.2787 g, V: 0.0509 g, and Se: 0.1924 g; Step 2: Vacuum package them together with a small amount and appropriate amount of tellurium tetrachloride as a transport agent in a quartz tube with a diameter of 10 mm and a length of 200 mm; Step 3: Place the packaged sample in a two-temperature-zone tube furnace, set the temperature to first rise to 950 °C at a rate of 3.0 °C / min, hold for 24 h, then rise to 1050 °C at a rate of 0.55 °C / min and hold for 168 h. After the high-temperature vacuum reaction is completed, take out the obtained sample to obtain high-quality magnetic Nb3VSe6 single crystals.

2. The preparation method of a nanocrystal magnetic material according to claim 1, wherein: The crystal has a centrosymmetrically broken hexagonal layered structure with a space group of P6322. V atoms are inserted between two 2H-NbS2 hexagonal layers, and the lattice constant 3. The preparation method of a nanocrystal magnetic material according to claim 1, characterized in that: The magnetism in the crystal is mainly contributed by trivalent V ions, with a magnetic moment of 3 μB and a local electron spin S = 3 / 2, while the conduction electrons originate from the unfilled band of Nb atoms.

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