Single crystal material with large perpendicular coercivity, preparation method and application thereof

Abstract

This invention patent discloses a single crystal material with large perpendicular coercivity, its preparation method and applications, specifically related to the technical field of single crystal materials. The self-flux method is used to grow Mn 2.45 Fe 0.58 Sn 0.97 single crystal. The preparation method of the single crystal material includes the following steps: preparing Mn, Fe, Sn raw materials; fully grinding the prepared raw materials and placing them in a quartz tube, then evacuating the quartz tube to a vacuum state and sealing the evacuated quartz tube; putting the sealed quartz tube into a muffle furnace and heating it to 1100°C at a heating rate of 100°C / h, holding at 1100°C for 24 h, then slowly cooling at a rate of 1°C / h, cooling down to 850°C, quenching after holding at 850°C for 24 hours, and a millimeter-sized high-quality Mn 2.45 Fe 0.58 Sn 0.97 single crystal can be obtained. By adopting the technical solution of this invention, a non-rare-earth permanent magnet Mn 2.45 Fe 0.58 Sn 0.97 single crystal with large perpendicular coercivity and low cost can be obtained, which helps to promote the development and utilization of high-density magnetic storage devices and non-rare-earth permanent magnets designed with high perpendicular magnetic anisotropy materials.

Description

Technical Field

[0001] The present invention relates to the technical field of single crystal materials, and particularly to single crystal materials with large perpendicular coercivity, and their preparation methods and applications. Background Art

[0002] In recent years, with the continuous progress of society and the rapid development of information technology, people's demand for high-reliability and high-storage-density storage technologies has been increasing. To further increase the recording density of storage media such as magneto-optical disks and magnetic disks, the size of magnetic units in the recording medium must be reduced to less than 10 nm. At such small sizes, the traditional in-plane magnetic anisotropy material as the storage medium in the horizontal recording mode will be affected by the superparamagnetic effect, making it difficult for magnetic recording units to maintain stable magnetic properties and even causing storage failure. However, ferromagnetic materials with high perpendicular magnetic anisotropy can overcome the superparamagnetic effect and achieve high-density perpendicular magnetic recording. Therefore, the perpendicular recording mode with perpendicular magnetic anisotropy materials as the storage medium is widely used in current hard disks. High-density information storage requires ferromagnetic materials to have perpendicular magnetic anisotropy on the one hand, and also requires magnetic materials to have a large coercive field on the other hand. This can improve the signal-to-noise ratio, reduce interference from adjacent bits, permanent magnets in the disk, and various other external electromagnetic noises, and overcome thermal disturbances and size effects after size reduction to maintain a stable magnetic state.

[0003] Spintronic devices use the spin of electrons to transmit, process, and store information, and have advantages that cannot be compared with current traditional microelectronics. Spintronic devices designed based on perpendicular easy magnetization materials mainly include high-speed, low-power magnetoresistive random access memories; magnetic sensors and hard disk read heads with high spatial resolution and high sensitivity; high-power microwave oscillators, spin optical isolators, and spin field effect transistors, etc. Therefore, magnetic materials with both high coercivity and high perpendicular magnetic anisotropy have broad application prospects and great commercial value in ultra-high-density perpendicular magnetic recording and high-performance spintronic devices, etc.

[0004] At present, due to the excellent properties such as high magnetic energy product and high coercivity of rare earth permanent magnet materials, they are a kind of permanent magnet materials with the highest comprehensive performance known so far. Now rare earth permanent magnet materials have been applied to all aspects of life, including many fields such as electronic information, automotive industry, medical equipment, and energy transportation. However, rare earth elements are non-renewable resources with very limited reserves, and the mining and processing costs are expensive. Therefore, people are urgently in need of finding high-performance permanent magnets that contain neither rare earth elements nor noble metal elements to replace the currently widely used rare earth magnets.

[0005] For ultra-high density magnetic storage, high-performance spintronic devices, or high-performance permanent magnets, it is necessary to find suitable new materials with high perpendicular magnetic anisotropy energy. Therefore, the present invention provides a single crystal material that simultaneously has an ultra-large coercive force and perpendicular easy magnetization characteristics, and this single crystal material has the advantages of containing neither precious metals nor rare earth elements, etc. Summary of the Invention

[0006] The present invention provides a single crystal material with a large perpendicular coercive force, a preparation method thereof, and an application, and this single crystal material has the advantages of containing neither precious metals nor rare earth elements, etc.

[0007] One technical solution of the present invention is as follows: A single crystal material with a large perpendicular coercive force is grown by the self-flux method of Mn 2.45 Fe 0.58 Sn 0.97 single crystal.

[0008] Another technical solution of the present invention is as follows: A preparation method of a single crystal material with a large perpendicular coercive force includes the following steps:

[0009] S1. Prepare the raw materials of Mn, Fe, and Sn according to a predetermined molar mass ratio;

[0010] S2. Thoroughly grind the raw materials prepared in step S1, then place the ground raw materials in a quartz tube, evacuate the quartz tube to a vacuum state, and then seal the evacuated quartz tube;

[0011] S3. Put the sealed quartz tube into a muffle furnace and heat it to a predetermined temperature. After maintaining the predetermined temperature for a predetermined time, slowly cool it. After cooling to a predetermined temperature, perform annealing and then quenching to obtain Mn with a large perpendicular coercive force 2.45 Fe 0.58 Sn 0.97 single crystal.

[0012] Further, the molar mass ratio of the raw materials Mn, Fe, and Sn in step S1 is 7:1.5:3.

[0013] Further, in step S3, when heating, heat it to 1100 °C at a heating rate of 100 °C / h and maintain it at 1100 °C for 24 h.

[0014] Further, in step S3, when cooling, slowly cool it at a rate of 1 °C / h, cool it to 850 °C, anneal it at 850 °C for 24 hours and then quench it. The slow cooling rate is beneficial to the preferential growth of single crystals. Annealing for 24 hours is to obtain a single crystal with uniform quality. The quenching treatment is to retain the high-temperature phase of the sample and finally obtain a high-quality single crystal sample.

[0015] Further, the Mn 2.45 Fe0.58 Sn 0.97 Single crystal materials are used to prepare high-density magnetic memories or high-performance permanent magnets.

[0016] Compared with the prior art, the beneficial effects of this solution are as follows:

[0017] This technical solution uses the self-assembly solvent method to prepare a non-rare-earth Mn 2.45 Fe 0.58 Sn 0.97 single crystal with a large coercivity. When an external magnetic field is perpendicular to the sample surface at 2K, the coercivity can reach 3T. Moreover, the single crystal material exhibits obvious perpendicular easy magnetization below 150K, showing broad application prospects in fields such as perpendicular magnetic storage and magnetic random access memory. At the same time, the preparation method of this technical solution is simple, with low cost, and the single crystal material has the advantages of containing neither precious metals nor rare earth elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the temperature rise and fall flowchart of the preparation method of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample in Example 1;

[0019] Figure 2 is the optical photograph of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample in Example 1;

[0020] Figure 3 is the Laue diffraction photograph of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample in Example 1;

[0021] Figure 4 is the magnetization curve of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample with the magnetic field parallel to the sample surface at different temperatures;

[0022] Figure 5 is the magnetization curve of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample with the magnetic field perpendicular to the sample surface at different temperatures;

[0023] Figure 6 is the schematic structural diagram of the high-density perpendicular magnetic recording device prepared from the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample in Example 2. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0025] Example 1

[0026] Single crystal material with large vertical coercivity, Mn with large vertical coercivity grown by self-solvent method 2.45 Fe 0.58 Sn 0.97 Single crystal sample. Mn 2.45 Fe 0.58 Sn 0.97 The single crystal material was prepared using Sn as a co-solvent. High-purity (99.99%) Mn, Fe, and Sn powders were used as raw materials in the experiment, and the quartz tube for growing the crystal was made of high-purity quartz.

[0027] As attached Figure 1 As shown, Mn 2.45 Fe 0.58 Sn 0.97 The method for preparing single crystal material comprises the following steps:

[0028] S1. Prepare Mn, Fe, and Sn raw materials according to the molar mass ratio of 7:1.5:3.

[0029] S2. Grind the raw materials prepared in step S1 thoroughly, then place the ground raw materials in a quartz tube, evacuate the quartz tube to a vacuum state, and then seal the vacuumed quartz tube.

[0030] S3. Place the sealed quartz tube in a muffle furnace and heat it to 1100℃ at a heating rate of 100℃ / h, keep it at 1100℃ for 24h, then slowly cool it down to 850℃ at a rate of 1℃ / h, keep it at 850℃ for 24h and quench it to obtain millimeter-level high-quality Mn 2.45 Fe 0.58 Sn 0.97 Single crystal.

[0031] The principle of this scheme: The self-solvent method is to dissolve the original components in the crystal with a low-melting-point solvent material, and make it into a saturated and uniform solution at a higher temperature. Then use slow cooling or other methods to reduce the solubility, and the solution becomes supersaturated, so that the crystal slowly nucleates and grows, and finally crystals are precipitated. The co-solvent method is a cheap and convenient method for growing crystals commonly used in laboratories. The sample grown in this embodiment uses excess Sn as a self-solvent. The melting point of Sn is 240°C and the boiling point is 2260°C. It is an ideal co-solvent. In addition, Sn as a co-solvent also participates in the growth of single crystals, and the quality of the sample will be relatively high.

[0032] likeFigure 2 As shown, the Mn 2.45 Fe 0.58 Sn 0.97 single crystal material is a hexagonal prism with a metallic luster, and Mn 2.45 Fe 0.58 Sn 0.97 single crystal has a size greater than or equal to 1x1x2 mm. Figure 3 The Laue spots in 2.45 Fe 0.58 Sn 0.97 show good symmetry and sharpness, which can prove that the prepared Mn

[0033] As Figure 4 and 5 shown, the magnetization curves of the Mn 2.45 Fe 0.58 Sn 0.97 single crystal sample at different temperatures and different magnetic field directions show that when the magnetic field is perpendicular to the sample surface, the hysteresis loop is approximately rectangular and the coercive force can reach 3 T at 2 K, while when the magnetic field is parallel to the sample surface, the hysteresis loop has almost no hysteresis. This proves that the sample is easy to magnetize vertically and has broad application prospects in fields such as perpendicular magnetic storage and magnetic random access memory.

[0034] Example 2

[0035] As Figure 6 shown, the prepared Mn 2.45 Fe 0.58 Sn 0.97 single crystal material is used to prepare high-performance permanent magnets or high-density magnetic memories, which include a magnetic storage medium composed of Mn 2.45 Fe 0.58 Sn 0.97 single crystal material.

[0036] In this example, the Mn 2.45 Fe 0.58 Sn 0.97 single crystal material has strong perpendicular easy magnetization characteristics and a large coercive force. When it is used to prepare high-density magnetic memories, it can overcome the insurmountable limit encountered in the traditional horizontal recording mode (i.e., the superparamagnetic effect caused by thermal perturbation). At the same time, because of the large coercive field, the signal-to-noise ratio is improved, and the interference from adjacent bits, permanent magnets in the disk, and various other external electromagnetic noises is reduced. After size reduction, it can overcome thermal perturbation and size effects and maintain a stable magnetic state to achieve high-density perpendicular magnetic recording.

[0037] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A single crystal material with a large perpendicular coercivity, characterized in that: Grown by the self-assembly solvent method Single crystal.

2. Preparation method of single crystal material with large perpendicular coercivity, characterized in that: It includes the following steps: S1. Prepare the Mn, Fe, and Sn raw materials according to a predetermined molar mass ratio; S2. Thoroughly grind the raw materials prepared in step S1, then place the ground raw materials in a quartz tube, evacuate the quartz tube to a vacuum state, and then seal the evacuated quartz tube; S3. Place the sealed quartz tube into a muffle furnace, heat it to a predetermined temperature, keep it at the predetermined temperature for a predetermined time, then slowly cool it down. After annealing at the predetermined temperature and then quenching, a single crystal with a large perpendicular coercivity can be obtained. single crystal.

3. The preparation method of the single crystal material with large perpendicular coercivity according to claim 2, characterized in that: In step S1, the molar mass ratio of the raw materials Mn, Fe, and Sn is 7:1.5:

3.

4. The preparation method of the single crystal material with large perpendicular coercivity according to claim 2, characterized in that: In step S3, when heating, heat to 1100 °C at a heating rate of 100 °C / h and hold at 1100 °C for 24 h.

5. The preparation method of the single crystal material with large perpendicular coercivity according to claim 2, characterized in that: In step S3, when cooling, slowly cool at a rate of 1 °C / h, cool down to 850 °C, anneal at 850 °C for 24 hours, and then quench.

6. Use of the single crystal material having a large perpendicular coercivity according to claim 1, characterized in that: The said single crystal material is used for preparing a high-density magnetic memory or a high-performance permanent magnet.

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