Preparation method of CeF3-doped M-type barium ferrite single crystal

Abstract

The invention provides a preparation method of a CeF3 doped M type barium ferrite single crystal. The preparation method comprises the following steps: S1, drying raw materials BaCO3, Fe2O3 and CeF3 and a fluxing agent LiF-NaF-B2O3; s2, raw materials BaCO3 and Fe2O3 are weighed, meanwhile, a proper amount of CeF3 powder is added, the raw materials and a fluxing agent LiF-NaF-B2O3 are mixed, and a mixed raw material is obtained; s3, putting the mixed raw material into a platinum crucible, sealing the platinum crucible, and filling protective gas; s4, the platinum crucible is heated, the temperature of the interior of the platinum crucible is increased to 1120-1200 DEG C, heat preservation is conducted, and the mixed raw materials are fully molten and homogenized; s5, cooling the interior of the platinum crucible to 990-1030 DEG C, lt; 001gt, 001gt; inserting the oriented seed crystal into a platinum crucible, and then cooling to 900-950 DEG C; s6, rotating the seed crystal, and meanwhile, adopting a lifting mode; and S7, annealing treatment is carried out, such that a complete single crystal is obtained. According to the invention, stable doping of Ce < 3 + > ions is realized, a pollution-free preparation process is adopted, large-size single crystals are prepared, and the performance of the prepared single crystals is optimized.

Description

Technical Field

[0001] This invention relates to the field of novel functional crystal materials technology, and in particular to a method for preparing CeF3-doped M-type barium ferrite single crystals. Background Technology

[0002] Traditional methods for preparing cerium-doped barium ferrite crystals mainly employ solid-state reaction methods and molten salt methods, but these methods currently have significant drawbacks:

[0003] (1) Solid-state reaction method, which involves mixing CeO2 with raw materials such as BaCO3 and Fe2O3 and then sintering at a high temperature above 1350℃. 4+ Difficult to fully reduce to Ce 3+ , making Ce 3+ The proportion is usually less than 40%, which leads to severe lattice distortion (c-axis expansion rate greater than 1.2%) and a significant reduction in saturation magnetization (usually less than 65 emu / g).

[0004] (2) Regarding the lead-containing molten salt method, Russian patent RU2692345C1 discloses a method for growing Ce-doped barium ferrite crystals using a PbO-B2O3 system, but the obtained crystal size is less than 3 mm, and there is a serious lead contamination problem (Pb residue greater than 800 ppm). The prior art also discloses a Bi-containing molten salt method for preparing Ce-doped barium ferrite crystals, but this method suffers from serious Bi contamination.

[0005] (3) Regarding the lead-free molten salt method, although the Na2CO3-NaCl molten salt system can achieve Ce doping, Ce... 3+ With Ce 4+ The ratio is uncontrollable, and the intrusion of Cl- ions into the lattice leads to a significant increase in the ferromagnetic resonance linewidth (ΔH>250Oe@10GHz).

[0006] None of the aforementioned existing technologies can simultaneously solve the three key technical challenges of valence state control, large-size growth, and pollution-free preparation.

[0007] In summary, the existing molten salt method for crystal preparation has a core defect:

[0008] (1) Price out of control: Ce 3+ Oxidation at high temperature to Ce 4+ (Conversion rate > 60%), induces lattice stress (cell parameter deviation > 1%);

[0009] (2) Small size: The maximum crystal size is <5mm, which cannot meet the requirements for device fabrication;

[0010] (3) Performance degradation: Ce 4+This results in a 30% reduction in the magnetocrystalline anisotropy field (from 17 kOe to 12 kOe);

[0011] (4) Severe pollution: The presence of Pb / Bi flux causes environmental pollution hazards. Summary of the Invention

[0012] This invention aims to provide a method for preparing CeF3-doped M-type barium ferrite single crystals, so as to achieve Ce... 3+ Stable doping of ions, pollution-free preparation process, preparation of large-size single crystals, and optimization of the performance of prepared single crystals.

[0013] Therefore, the technical solution adopted in this invention is: a method for preparing CeF3-doped M-type barium ferrite single crystal, comprising the following steps:

[0014] S1. Raw material pretreatment: Dry the raw materials BaCO3, Fe2O3 and CeF3 with the flux LiF-NaF-B2O3 at 110-120℃ for 12-15h.

[0015] S2. Raw material mixing: Weigh the raw materials BaCO3 and Fe2O3 at a molar ratio of 1:(12.5-12.8), wherein Fe2O3 is in excess by 5-8%, and add an appropriate amount of CeF3 powder, with the mass percentage of Fe2O3 to CeF3 being 100:(1-5). Mix the above raw materials to obtain a preliminary mixture, and then mix the preliminary mixture with the flux LiF-NaF-B2O3 at a molar ratio of 1:(20-40) to obtain a mixed raw material.

[0016] S3. Loading and sealing: The mixed raw materials are loaded into a platinum crucible, the platinum crucible is sealed, and a protective gas is introduced into the platinum crucible.

[0017] S4. Melting treatment: The platinum crucible is heated to 1120-1200℃, and the interior of the platinum crucible is kept warm to fully melt and homogenize the mixed raw materials.

[0018] S5. Crystal growth: The temperature inside the platinum crucible is lowered to 990-1030℃, and then... <001> The oriented seed crystal is inserted into the platinum crucible, and then the interior of the platinum crucible is cooled to 900-950°C.

[0019] S6. Growth control: The seed crystal is rotated while being pulled up.

[0020] S7. Annealing treatment: After the crystal growth is completed, it is cooled to room temperature to obtain a complete CeF3-doped M-type barium ferrite single crystal.

[0021] As a preferred embodiment of the above scheme, in step S2, the molar ratio of LiF, NaF and B2O3 in the flux is (35-40):(35-40):(30-20), and the purity of the CeF3 powder is above 99.9%.

[0022] More preferably, in step S2, the raw materials and flux are mixed using a planetary ball mill or a mixer.

[0023] More preferably, when the planetary ball mill is used for mixing, the raw materials and flux are mixed in an ethanol medium for 24-26 hours, the rotation speed of the planetary ball mill is 300-350 rpm, and the ball-to-material ratio is (5-8):1.

[0024] More preferably, in step S3, the platinum crucible is sealed by argon arc welding, the protective gas is nitrogen or an inert gas, and the oxygen content of the protective gas is <1ppm.

[0025] More preferably, in step S4, the heating rate inside the platinum crucible is 5-7℃ / min, and the holding time is 24-26h.

[0026] More preferably, in step S5, before the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.2-0.4℃ / min, and after the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.5-0.8℃ / h, and the seed crystal is a barium ferrite single crystal wafer.

[0027] More preferably, in step S6, the rotational speed of the seed crystal is 20-25 rpm, and the pulling speed is 0.2-0.5 mm / day.

[0028] More preferably, in step S7, the cooling rate of the crystal is 10-15°C / h.

[0029] The beneficial effects of this invention are:

[0030] 1. Breakthrough in valence state stability: XPS analysis confirmed that CeF3-doped M-type barium ferrite single crystals prepared in this invention exhibited stable valence state. 3 + The proportion reached 76.9%, effectively suppressing Ce. 4+ The generation of ions solved the problem of Ce. 4+ The performance degradation caused by excessive proportion has been addressed by Ce. 3+ Stable doping of ions.

[0031] 2. Preparation of large-size single crystals: The CeF3-doped M-type barium ferrite single crystal prepared by this invention has a size of 20mm×16mm×10mm, which breaks through the size limitation of crystals smaller than 5mm prepared by existing technologies.

[0032] 3. Achieving a pollution-free preparation process: This invention uses a lead-free LiF-NaF-B2O3 composite flux to ensure that the heavy metal residue is less than 3ppm, which complies with the international RoHS standard.

[0033] 4. Performance optimization of the prepared single crystal: The CeF3-doped M-type barium ferrite single crystal prepared by this invention is a pure phase, free of any impurity phases. The single crystal exhibits a coercive field of 251.2 Oe, a remanent magnetization of 12.8 emu / g, and a saturation magnetization of 65.2 emu / g, demonstrating excellent magnetic properties. The ferromagnetic resonance linewidth ΔH of the CeF3-doped M-type barium ferrite single crystal prepared by this invention is 28 Oe@10 GHz, less than 30 Oe@10 GHz, and the saturation magnetization is increased to over 65 emu / g, resulting in excellent microwave performance.

[0034] 5. With broad application prospects, the CeF3-doped M-type barium ferrite single crystal prepared by this invention represents a breakthrough in size and quality, and is expected to be successfully applied in fields such as millimeter-wave circulators, quantum devices, and magneto-optical devices. Attached Figure Description

[0035] Figure 1 This is a physical image of the CeF3-doped M-type barium ferrite single crystal prepared according to the present invention.

[0036] Figure 2 This is a powder diffraction pattern of the CeF3-doped M-type barium ferrite single crystal prepared according to the present invention.

[0037] Figure 3 This is a hysteresis loop diagram of the CeF3-doped M-type barium ferrite single crystal prepared in this invention. Detailed Implementation

[0038] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0039] Example 1:

[0040] A method for preparing CeF3-doped M-type barium ferrite single crystal includes the following steps:

[0041] S1. Raw material pretreatment: BaCO3, Fe2O3 and CeF3 are dried with flux LiF-NaF-B2O3 at 110℃ for 12h.

[0042] S2. Raw material mixing: Weigh BaCO3 and Fe2O3 at a molar ratio of 1:12.5, with Fe2O3 in excess by 5%. At the same time, add an appropriate amount of CeF3 powder, with the mass percentage of Fe2O3 to CeF3 being 100:1. Mix the above raw materials to obtain a preliminary mixture. Then mix the preliminary mixture with the flux LiF-NaF-B2O3 at a molar ratio of 1:40 to obtain a mixed raw material.

[0043] In step S2, the molar ratio of LiF, NaF, and B2O3 in the flux is 40:40:20, and the purity of the CeF3 powder is above 99.95%. In step S2, a planetary ball mill or a mixer is used to mix the raw materials and flux. When using a planetary ball mill, both the raw materials and flux are mixed in an ethanol medium for 24 hours. The planetary ball mill rotates at 300 rpm, and the ball-to-material ratio is 5:1.

[0044] S3. Loading and sealing: Load the mixed raw materials into the platinum crucible, seal the platinum crucible, and fill the platinum crucible with protective gas.

[0045] In step S3, the platinum crucible is sealed by argon arc welding, and the protective gas is nitrogen or an inert gas with an oxygen content of 0.6 ppm.

[0046] S4. Melting treatment: The platinum crucible is heated to 1120°C, and the interior of the platinum crucible is kept warm to fully melt and homogenize the mixed raw materials.

[0047] In step S4, the heating rate inside the platinum crucible is 5°C / min, and the holding time is 24h.

[0048] S5. Crystal growth: The inside of the platinum crucible is cooled to 990℃, and then... <001> The oriented seed crystal is inserted into the platinum crucible, and then the inside of the platinum crucible is cooled to 900°C.

[0049] In step S5, before the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.2℃ / min, and after the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.5℃ / h. The seed crystal is a barium ferrite single crystal wafer.

[0050] S6. Growth control: The seed crystal is rotated while being pulled.

[0051] In step S6, the seed crystal rotates at a speed of 20 rpm and the pulling speed is 0.2 mm / day.

[0052] S7. Annealing treatment: After the crystal growth is completed, it is cooled to room temperature to obtain a complete CeF3-doped M-type barium ferrite single crystal.

[0053] In step S7, the cooling rate of the crystal is 10℃ / h.

[0054] Example 2:

[0055] A method for preparing CeF3-doped M-type barium ferrite single crystal includes the following steps:

[0056] S1. Raw material pretreatment: BaCO3, Fe2O3 and CeF3 are dried with flux LiF-NaF-B2O3 at 115℃ for 14h.

[0057] S2. Raw material mixing: Weigh BaCO3 and Fe2O3 at a molar ratio of 1:12.7, with Fe2O3 in excess by 7%. At the same time, add an appropriate amount of CeF3 powder, with the mass percentage of Fe2O3 to CeF3 being 100:3. Mix the above raw materials to obtain a preliminary mixture. Then mix the preliminary mixture with the flux LiF-NaF-B2O3 at a molar ratio of 1:30 to obtain a mixed raw material.

[0058] In step S2, the molar ratio of LiF, NaF, and B2O3 in the flux is 38:38:24, and the purity of the CeF3 powder is above 99.97%. In step S2, a planetary ball mill or a mixer is used to mix the raw materials and flux. When using a planetary ball mill, both the raw materials and flux are mixed in an ethanol medium for 25 hours. The rotation speed of the planetary ball mill is 340 rpm, and the ball-to-material ratio is 7:1.

[0059] S3. Loading and sealing: Load the mixed raw materials into the platinum crucible, seal the platinum crucible, and fill the platinum crucible with protective gas.

[0060] In step S3, the platinum crucible is sealed by argon arc welding, and the protective gas is nitrogen or an inert gas with an oxygen content of 0.7 ppm.

[0061] S4. Melting treatment: The platinum crucible is heated to 1160°C, and the interior of the platinum crucible is kept warm to fully melt and homogenize the mixed raw materials.

[0062] In step S4, the heating rate inside the platinum crucible is 6°C / min, and the holding time is 25h.

[0063] S5. Crystal growth: The temperature inside the platinum crucible is lowered to 1100℃, and then... <001> The oriented seed crystal is inserted into the platinum crucible, and then the inside of the platinum crucible is cooled to 930°C.

[0064] In step S5, before the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.3℃ / min, and after the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.6℃ / h. The seed crystal is a barium ferrite single crystal wafer.

[0065] S6. Growth control: The seed crystal is rotated while being pulled.

[0066] In step S6, the seed crystal rotates at a speed of 23 rpm and the pulling speed is 0.4 mm / day.

[0067] S7. Annealing treatment: After the crystal growth is completed, it is cooled to room temperature to obtain a complete CeF3-doped M-type barium ferrite single crystal.

[0068] In step S7, the cooling rate of the crystal is 13°C / h.

[0069] Example 3:

[0070] A method for preparing CeF3-doped M-type barium ferrite single crystal includes the following steps:

[0071] S1. Raw material pretreatment: BaCO3, Fe2O3 and CeF3 are dried with flux LiF-NaF-B2O3 at 120℃ for 15h.

[0072] S2. Raw material mixing: Weigh BaCO3 and Fe2O3 at a molar ratio of 1:12.8, with Fe2O3 in excess by 8%. At the same time, add an appropriate amount of CeF3 powder, with the mass percentage of Fe2O3 to CeF3 being 100:5. Mix the above raw materials to obtain a preliminary mixture. Then mix the preliminary mixture with the flux LiF-NaF-B2O3 at a molar ratio of 1:20 to obtain a mixed raw material.

[0073] In step S2, the molar ratio of LiF, NaF, and B2O3 in the flux is 35:35:30, and the purity of the CeF3 powder is above 99.99%. In step S2, a planetary ball mill or a mixer is used to mix the raw materials and flux. When using a planetary ball mill, both the raw materials and flux are mixed in an ethanol medium for 26 hours. The planetary ball mill rotates at 350 rpm, and the ball-to-material ratio is 8:1.

[0074] S3. Loading and sealing: Load the mixed raw materials into the platinum crucible, seal the platinum crucible, and fill the platinum crucible with protective gas.

[0075] In step S3, the platinum crucible is sealed by argon arc welding, and the protective gas is nitrogen or an inert gas with an oxygen content of 0.9 ppm.

[0076] S4. Melting treatment: The platinum crucible is heated to 1200°C, and the interior of the platinum crucible is kept warm to fully melt and homogenize the mixed raw materials.

[0077] In step S4, the heating rate inside the platinum crucible is 7°C / min, and the holding time is 26h.

[0078] S5. Crystal growth: The temperature inside the platinum crucible is lowered to 1030℃, and then... <001> The oriented seed crystal is inserted into the platinum crucible, and then the inside of the platinum crucible is cooled to 950°C.

[0079] In step S5, before the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.4℃ / min, and after the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.8℃ / h. The seed crystal is a barium ferrite single crystal wafer.

[0080] S6. Growth control: The seed crystal is rotated while being pulled.

[0081] In step S6, the seed crystal rotates at a speed of 25 rpm and the pulling speed is 0.5 mm / day.

[0082] S7. Annealing treatment: After the crystal growth is completed, it is cooled to room temperature to obtain a complete CeF3-doped M-type barium ferrite single crystal.

[0083] In step S7, the cooling rate of the crystal is 15°C / h.

[0084] Innovative Mechanism 1: Fluorine-mediated 4f-3d orbital hybridization and quantum confinement effect.

[0085] (1) Construction of cerium fluoride quantum dot templates: In high-temperature melts, CeF3 does not completely dissociate into free ions. By precisely controlling the thermodynamic pathway, we induce some CeF3 to exist as sub-nanometer clusters (CeF3). n The (n=3-5) form exists temporarily and stably. Under the constraint of the B2O3 network, these clusters serve as "pre-structured templates," and their lattice constants are coherently matched with the atomic spacing of specific crystal planes of barium ferrite, which greatly reduces the interfacial energy of heterogeneous nucleation.

[0086] (2) Inducing 4f-3d orbital hybridization: The extremely strong electronegativity of F- not only attracts electrons, but more importantly, as a strong-field ligand, it can significantly suppress Ce. 3+ The 4f orbital energy level makes it compatible with the neighboring Fe. 3+ The 3d orbital energy levels are much closer. This energy level approximation forces the originally localized 4f electrons to undergo unprecedented strong orbital hybridization with the itinerant 3d electrons, forming a new type of hybrid electronic state.

[0087] (3) Quantum confinement and giant Faraday effect: The hybrid electronic states are spatially confined within Ce-O-Fe atomic clusters, which is equivalent to generating atomic-scale quantum dots. This quantum confinement effect leads to the quantization of their electronic energy levels, resulting in huge exciton transition oscillator strengths near specific wavelengths (such as 1550 nm). This can cause an order-of-magnitude increase in the Faraday rotation angle of the material.

[0088] Innovation Mechanism 2: Selective phonon scattering and ultra-low microwave loss driven by phonon engineering.

[0089] (1) F-modified phonon spectrum and creation of phonon band gap: After F-ions enter the crystal lattice, due to their mass and O 2- Different and stronger bonds significantly alter the intrinsic phonon spectrum of barium ferrite. First-principles calculations show that F - Substitution at a specific location (such as the 12k crystal site) will introduce a local phonon bandgap in the terahertz frequency band (~30-50THz, corresponding to the multiphonon process in the 10-20GHz microwave band).

[0090] (2) Suppression of multiphonon processes and energy dissipation: Microwave energy loss largely originates from the interaction between microwave photons and lattice phonons (multiphonon processes). The existence of the aforementioned phonon bandgap is equivalent to setting up a "forbidden zone" on the critical energy transmission channel, effectively blocking multiphonon scattering paths that may lead to energy dissipation. This allows microwave energy to pass through the lattice more undamagedly, resulting in extremely low dielectric loss and ferromagnetic resonance linewidth on a macroscopic scale.

[0091] (3) Minimize phonon-spin coupling: Through F-engineering, we have achieved a "surgical" precise trimming of the phonon spectrum, which minimizes the coupling strength between phonons and spin waves in a specific frequency band, thereby ensuring the high fidelity of spin information during transmission.

[0092] Innovation Mechanism 3: Defect self-healing mechanism based on dynamic interlocking of fluorine / boron-oxygen network.

[0093] (1) Formation of FBO dynamic interlocking network: In the melt, F - It does not exist in isolation; it interacts intensely with the B2O3 network, partially replacing the BOB bridging oxygen bonds to form flexible, dynamic connections within the FBOF network. This network possesses both the strength of the BO covalent bonds and the flexibility of the B / F ionic bonds, creating a self-reconfigurable "smart gel" environment.

[0094] (2) Real-time sensing and repair of solid-liquid interface defects: This dynamic network can respond in real time to the stress field and chemical potential gradient at the crystal growth interface. When the interface is about to generate dislocations due to growth rate fluctuations, the FBO bonds in the network will break and recombine rapidly, transporting or removing ions to the interface like "tiny hands". At the instant of defect nucleation (on the picosecond scale), it provides local rheological relaxation, releases stress, and thus achieves "self-repair" of defects.

[0095] (3) Obtaining near-ideal crystals: This mechanism ensures that crystal growth is always carried out under conditions close to thermodynamic equilibrium, thereby enabling the preparation of "near-ideal" single crystals with dislocation density close to zero, whose internal quality far exceeds that of crystals prepared by traditional methods.

[0096] An excess of 5-8% Fe2O3 can compensate for the loss of Fe at high temperatures. 3+ The evaporation loss. The CeF3-doped M-type barium ferrite single crystal CeF3:BaM (molecular formula BaFe) prepared in this invention... 11.99 Ce 0.01 O 19 The advantage of this material lies in its dual valence state stabilization mechanism through boron network shielding, which overcomes the valence state control and size bottleneck of cerium ion-doped single crystals, providing a revolutionary material for quantum information technology and terahertz communication.

[0097] This invention innovatively uses CeF3 as a dopant source, combined with an optimized LiF-NaF-B2O3 ternary molten salt system, to achieve Ce... 3+ The efficient and stable doping of ions and the controllable preparation of large-size single crystals are key advantages. The CeF3-doped BaM single crystals prepared in this invention have significant application value in core devices such as self-biased circulators, low insertion loss microwave antennas, and magneto-optical isolators. They are particularly suitable for the millimeter-wave band (24-100GHz) of fifth-generation (5G) and sixth-generation (6G) mobile communication systems, as well as for high-performance, low-loss microwave devices.

[0098] The present invention Figure 1 The physical specimen of the CeF3-doped M-type barium ferrite single crystal prepared according to the present invention is shown. Figure 2 The powder diffraction pattern of the CeF3-doped M-type barium ferrite single crystal prepared according to the present invention is shown. Figure 3 The hysteresis loop of the CeF3-doped M-type barium ferrite single crystal prepared in this invention is shown.

[0099] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing CeF3-doped M-type barium ferrite single crystal, characterized in that, Includes the following steps: S1. Raw material pretreatment: Dry the raw materials BaCO3, Fe2O3 and CeF3 with the flux LiF-NaF-B2O3 at 110-120℃ for 12-15h. S2. Raw material mixing: Weigh the raw materials BaCO3 and Fe2O3 at a molar ratio of 1:(12.5-12.8), wherein Fe2O3 is in excess by 5-8%, and add an appropriate amount of CeF3 powder, with the mass percentage of Fe2O3 to CeF3 being 100:(1-5). Mix the above raw materials to obtain a preliminary mixture, and then mix the preliminary mixture with the flux LiF-NaF-B2O3 at a molar ratio of 1:(20-40) to obtain a mixed raw material. S3. Loading and sealing: The mixed raw materials are loaded into a platinum crucible, the platinum crucible is sealed, and a protective gas is introduced into the platinum crucible. S4. Melting treatment: The platinum crucible is heated to 1120-1200℃, and the interior of the platinum crucible is kept warm to fully melt and homogenize the mixed raw materials. S5. Crystal growth: The temperature inside the platinum crucible is lowered to 990-1030℃, and then... <001> The oriented seed crystal is inserted into the platinum crucible, and then the interior of the platinum crucible is cooled to 900-950°C. S6. Growth control: The seed crystal is rotated while being pulled up. S7. Annealing treatment: After the crystal growth is completed, it is cooled to room temperature to obtain a complete CeF3-doped M-type barium ferrite single crystal.

2. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S2, the molar ratio of LiF, NaF and B2O3 in the flux is (35-40):(35-40):(30-20), and the purity of the CeF3 powder is above 99.9%.

3. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S2, the raw materials and flux are mixed using a planetary ball mill or a mixer.

4. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 3, characterized in that: When the planetary ball mill is used for mixing, the raw materials and flux are mixed in ethanol medium for 24-26 hours. The rotation speed of the planetary ball mill is 300-350 rpm, and the ball-to-material ratio is (5-8):

1.

5. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S3, the platinum crucible is sealed by argon arc welding, and the protective gas is nitrogen or an inert gas with an oxygen content of <1ppm.

6. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S4, the heating rate inside the platinum crucible is 5-7℃ / min, and the holding time is 24-26h.

7. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S5, before the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.2-0.4℃ / min, and after the seed crystal is inserted into the platinum crucible, the cooling rate inside the platinum crucible is 0.5-0.8℃ / h. The seed crystal is a barium ferrite single crystal wafer.

8. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S6, the rotational speed of the seed crystal is 20-25 rpm, and the pulling speed is 0.2-0.5 mm / day.

9. The method for preparing a CeF3-doped M-type barium ferrite single crystal according to claim 1, characterized in that: In step S7, the cooling rate of the crystal is 10-15℃ / h.

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