A method for promoting the growth of strontium tantalum lanthanum aluminate twins

Abstract

This invention discloses a method for promoting the growth of strontium tantalum lanthanum aluminate twins, comprising the following steps: After uniformly mixing the raw materials, placing them in a crucible and then feeding them into a high-temperature furnace for high-temperature melting; introducing a twin seed crystal and using a pulling method to slowly lift the twin seed crystal from the molten raw materials to pull the twin crystal; during the pulling growth process, using a weighing device to collect the weight data of the growing twin crystal in real time; dynamically and synchronously adjusting the pulling speed of the pulling device and the temperature gradient of the high-temperature furnace according to the weight change trend of the twin crystal; after growth is completed, reducing the temperature and pressure in the furnace cavity to remove the grown strontium tantalum lanthanum aluminate twins. This invention features a novel design, utilizing a dual-variable synergistic control design to improve upon the traditional pulling method's tendency for twin crystals to degenerate into single crystals, significantly enhancing the robustness and yield of the twin pulling process.

Description

Technical Field

[0001] This invention relates to the field of twin crystal pulling technology, and more particularly to a method for promoting the growth of strontium tantalum lanthanum aluminate twin crystals. Background Technology

[0002] Lanthanum strontium aluminate biscrystalline material (LaAlO3-Sr2AlTaO6, abbreviated as LSAT biscrystalline material) is a synthetic perovskite-structured crystal that is irreplaceable in superconducting quantum interference devices (SQIs). It is primarily used in sensitive detection devices such as SQIs, and also shows great promise in cutting-edge fields such as microwave radio frequency and integrated optics. Current methods for preparing LSAT biscrystalline materials involve optical processing and hot-pressing sintering. However, this process results in voids and discontinuities at the grain boundaries, limiting its practical application. Furthermore, using the Czochralski process can easily lead to the biscrystalline material degenerating into a single crystal. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies, such as the presence of voids and discontinuities at the grain boundaries of strontium tantalum aluminate twins during hot-pressing sintering, and the tendency for twins to degenerate into single crystals during the Czochralski process. Therefore, this invention proposes a method to promote the growth of strontium tantalum aluminate twins.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for promoting the growth of strontium tantalum aluminate twins includes the following steps:

[0006] S1. After the raw materials are mixed evenly, they are placed in a crucible and then sent into a high-temperature furnace for high-temperature melting.

[0007] S2. Introduce a twin seed crystal and use an upward pulling method to control the twin seed crystal to be slowly pulled up from the molten raw material in order to pull the twin crystal.

[0008] S3. During the upward growth process, the weight data of the growing bicrystalline crystal is collected in real time using a weighing device.

[0009] S4. Based on the weight change trend of the twin crystal, dynamically and synchronously adjust the pulling speed of the pulling device and the temperature gradient of the high-temperature furnace to maintain the coherent and stable growth of the twin crystal interface.

[0010] S5. After growth is complete, reduce the temperature and pressure inside the furnace cavity to remove the grown strontium tantalum lanthanum aluminate twin crystals.

[0011] Preferably, the raw materials include lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide;

[0012] The mass ratio of lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide is as follows: lanthanum oxide 15.0–26.0 parts, aluminum oxide 12.0–16.0 parts, strontium carbonate 38.0–50.0 parts, and tantalum oxide 28.0–38.0 parts.

[0013] Preferably, in step S2, the initial pulling speed of the pulled bicrystalline crystal is controlled at 0.3 mm / h to 0.5 mm / h;

[0014] In step S4, the total range of the bicrystalline crystal pulling speed during the dynamic control process is controlled within 0.1 mm / h to 2.0 mm / h.

[0015] Preferably, in step S2, the initial temperature gradient of the high-temperature furnace is controlled between 5℃ / cm and 20℃ / cm;

[0016] The melting temperature of the high-temperature furnace is controlled between 1800℃ and 2200℃.

[0017] Preferably, the process of pulling the bicrystalline crystal is carried out under a protective atmosphere of inert gas.

[0018] Preferably, in step S4, the dynamic control step specifically includes the following sub-steps:

[0019] K1, Data Acquisition: Data is acquired at set time intervals Δt, showing the growth of the bicrystalline crystal at the current time. The real-time mass m(t) at time t and the mass m(t+Δt) at the next time t;

[0020] K2. Rate Calculation: Calculate the current actual crystal growth rate v based on the mass change within adjacent time nodes. g (t);

[0021] K3, Deviation Confirmation: The actual crystal growth rate v g (t) and the preset target growth rate v g,target Compare the values ​​to determine the growth rate deviation.

[0022] K4. Parameter Compensation: Based on the growth rate deviation value, the corrected lifting speed and the corrected temperature gradient are calculated synchronously through the automated feedback control system, and real-time adjustments are performed.

[0023] More preferably, in sub-step K2, the actual crystal growth rate v g The formula for calculating (t) is as follows:

[0024]

[0025] In the formula: m(t+Δt)-m(t) is the change in the mass of the twin crystals within the time interval Δt;

[0026] ρ is the density of the bicrystalline crystal;

[0027] A is the cross-sectional area of ​​the twin crystal.

[0028] More preferably, in sub-step K4, the corrected lifting speed is calculated using the following speed adjustment formula:

[0029]

[0030] In the formula: v new The corrected lifting speed;

[0031] v current The current lifting speed;

[0032] k v This is the speed adjustment coefficient.

[0033] More preferably, in sub-step K4, the dynamic adjustment formula for the corrected temperature gradient is as follows:

[0034]

[0035] In the formula: G new This is the corrected temperature gradient;

[0036] G current This represents the current temperature gradient;

[0037] k G This is the temperature gradient adjustment coefficient.

[0038] More preferably: the speed adjustment coefficient k v It ranges from 0.05 to 0.2;

[0039] The temperature gradient adjustment coefficient k G It ranges from 0.01 to 0.1.

[0040] Compared with the prior art, the beneficial effects of the present invention are:

[0041] 1. In this invention, during the twin crystal pulling process, the growth parameters are dynamically adjusted based on the weighing data, which can effectively avoid defects and inhomogeneities within the crystal, improve the quality and dimensional consistency of the twin crystal, and ensure extremely high consistency of the strontium tantalum lanthanum aluminate twin crystal in terms of external dimensions and internal grain boundary straightness.

[0042] 2. In this invention, by dynamically adjusting the pulling speed and the temperature gradient at the crystallization front, the positive resultant force or negative feedback counterbalancing mechanism of the two is used to perfectly counteract the damage of abnormal crystallization flow rate to the bicrystalline coherent interface, thus ensuring the flatness of the coherent grain boundary.

[0043] 3. In this invention, by limiting the initial pulling speed, initial temperature gradient and total dynamic control range within a specific optimization range, and with fine feedback compensation, the actual crystallization flow rate is stabilized near the preset target value. The resulting strontium tantalum lanthanum aluminate bicrystalline crystal has regular shape and size, low internal stress, high mechanical strength and excellent grain boundary integrity.

[0044] 4. In this invention, the automatic feedback of the control system enables rapid dynamic adjustment, smoothly pulling the crystal solidification rate back to the target steady state without human intervention. This effectively prevents thermal shock defects and crystal cracking, giving the Strontium Tantalum Lanthanum Aluminate double crystal pulling process a strong ability to resist extreme environmental disturbances, and significantly improving process robustness and yield.

[0045] This invention features a novel design that utilizes a dual-variable synergistic control approach. This improves upon the traditional Czochralski method, which, when subjected to abnormal crystal growth, is prone to severe bending of the solid-liquid interface due to single-variable adjustment, leading to the degradation of bicrystalline crystals into monocrystalline crystals. This significantly enhances the robustness and yield of the bicrystalline Czochralski process. Detailed Implementation

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0047] This invention provides a method for promoting the growth of strontium-tantalum-lanthanum aluminate twins. Addressing the problem that existing methods for preparing strontium-tantalum-lanthanum aluminate twins using optical processing and hot-pressing sintering result in voids and discontinuities at grain boundaries, thus limiting their practical application, this invention innovatively employs the preparation of twin seed crystals and the Czochralski method to grow the twin crystals, thereby obtaining high-quality grain boundary twin crystals. The main process steps are as follows:

[0048] S1. Preparation of Raw Materials: Mix the lanthanum tantalum aluminate crystal raw materials evenly and load them into a crucible. The raw materials include lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide. The mass ratio of lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide is controlled as follows: lanthanum oxide 15.0–26.0 parts, aluminum oxide 12.0–16.0 parts, strontium carbonate 38.0–50.0 parts, and tantalum oxide 28.0–38.0 parts. Place the crucible containing the raw materials in a high-temperature furnace.

[0049] S2. Setting Growth Conditions and Climbing Growth: The temperature gradient, pressure, and growth rate are set. An inert gas is introduced into the high-temperature furnace to prevent oxidation of the raw material or contamination by impurities. During growth, the twin seed crystal is slowly lifted from the molten raw material using a climbing device, controlling the cooling rate of the crystal to promote twin growth. Specifically, the initial lifting speed is controlled at 0.3 mm / h to 0.5 mm / h, the initial temperature gradient is controlled at 5 ℃ / cm to 20 ℃ / cm, and the melting temperature of the high-temperature furnace is controlled at 1800 ℃ to 2200 ℃.

[0050] S3. Real-time weighing monitoring: During the lifting process, a high-precision weighing device is used to monitor the growing twin crystals in real time and adjust the growth parameters to maintain the stability and uniformity of the twin crystal quality.

[0051] S4. Crystal Growth Optimization: Based on real-time weighing data, the growth rate and temperature gradient are dynamically adjusted to optimize the growth process of strontium tantalum aluminate twin crystals, improve the quality and size of the twin crystals, and the dynamic adjustment specifically includes the following steps:

[0052] K1, Data Acquisition: Data is acquired at set time intervals Δt, showing the growth of the bicrystalline crystal at the current time. The real-time mass m(t) at time t and the mass m(t+Δt) at the next time t.

[0053] K2. Rate Calculation: Calculate the current actual crystal growth rate v based on the mass change within adjacent time nodes. g (t), the calculation formula is:

[0054]

[0055] In the formula: m(t+Δt)-m(t) is the time interval. The change in the quality of the internal twin;

[0056] ρ is the density of the bicrystalline crystal;

[0057] A is the cross-sectional area of ​​the twin crystal.

[0058] K3, Deviation Confirmation: The actual crystal growth rate v g (t) and the preset target growth rate v g,target Compare the values ​​to determine the growth rate deviation.

[0059] K4. Parameter Compensation: Based on the growth rate deviation value, the corrected lifting speed and the corrected temperature gradient are synchronously calculated by the automated feedback control system, and real-time adjustments are performed. The corrected lifting speed is calculated using the following speed adjustment formula:

[0060]

[0061] In the formula: v new The corrected lifting speed;

[0062] v current The current lifting speed;

[0063] k v The empirical speed control gain, i.e., the speed adjustment coefficient, k v =0.05~0.2.

[0064] The corrected dynamic adjustment formula for the temperature gradient is as follows:

[0065]

[0066] In the formula: G new This is the corrected temperature gradient;

[0067] G current This represents the current temperature gradient;

[0068] k G This represents the empirical temperature gradient control gain, i.e., the temperature gradient adjustment coefficient. k G =0.01~0.1.

[0069] K5. Feedback Control: The above adjustment steps are automated through a computer system, which analyzes the weighing data in real time and provides feedback to adjust the growth parameters, ensuring stability and optimization during the growth process.

[0070] S5. After growth is complete, reduce the temperature and pressure inside the furnace cavity, then open the furnace cavity and remove the grown strontium tantalum lanthanum aluminate twin crystals.

[0071] The specific implementation is as follows:

[0072] Example 1

[0073] Step 1: Select 14.2g of high-purity alumina, 20.6g of lanthanum oxide, 44.9g of strontium carbonate, and 33.6g of tantalum oxide, mix them evenly, and put them into a crucible.

[0074] Step 2: Place the crucible containing the raw materials in a high-temperature furnace and heat it to 1900℃ to completely melt the raw materials. High-purity nitrogen gas is purged throughout the process to prevent oxidation of the raw materials or contamination by impurities. Adjust the power ratio of the heating element to establish an initial temperature gradient G. current =10℃ / cm.

[0075] Step 3: During the growth process, the twin seed crystal is slowly lifted from the molten raw material at an initial speed of 0.4 mm / h using an upward lifting device. A real-time high-precision weighing device with an accuracy of 0.01 grams is activated for monitoring. The target growth rate v is set. g,target=1.5mm / h; Set adjustment coefficient k v =0.1, k G =0.05.

[0076] Step 4: At a certain moment during the twin-crystal constant-diameter growth stage, the control system collects and measures the following parameters: current lifting speed v current =1.4mm / h;

[0077] Current temperature gradient G current =10℃ / cm;

[0078] The actual growth rate v was measured g (t) = 1.3 mm / h.

[0079] The control system automatically performs the following compensation calculations:

[0080]

[0081]

[0082] The control system immediately compensated for the speed of the lifting motor by fine adjustment to 1.42 mm / h, and synchronously adjusted the temperature gradient to 10.01℃ / cm by controlling the power ratio.

[0083] In this scenario, the deviation value (v) g,target - v g (t) is a positive value. The formula is modified by increasing the lifting speed v. new And simultaneously increase the temperature gradient G at the solid-liquid interface. new On the one hand, it accelerates the upward pulling rate of the crystal, and on the other hand, it increases the heat transfer and cooling driving force at the crystallization front. The positive resultant force of the two guides the crystallization rate of the twin crystals to quickly approach the target value of 1.5 mm / h, avoiding excessive local thickening of the crystals due to prolonged residence, and ensuring the stability of twin crystal growth.

[0084] Step 5: After growth is complete, reduce the temperature and pressure inside the furnace, then open the furnace and remove the grown strontium tantalum lanthanum aluminate twin crystals.

[0085] Example 2

[0086] It is basically the same as Example 1, except that:

[0087] In step four, during the later stages of continuous twin crystal pulling, localized abnormal thermal convection within the melt causes localized supercooling at the crystallization front, resulting in a sudden increase in the crystal mass flow rate. At this point, the weighing device detects a steeper slope in the mass growth rate, and the control system calculates the current actual growth rate v. g (t) = 1.7 mm / h, at this time the current real-time parameter recorded by the system is: current lifting speed v current=1.5mm / h, current crystallization front temperature gradient G current =10.05℃ / cm. The control system automatically performs the following compensation calculation:

[0088]

[0089]

[0090] Based on the calculation results, the control system immediately reduced the operating speed of the lifting mechanism to 1.48 mm / h, and at the same time fine-tuned the heating power ratio to steadily reduce the temperature gradient at the crystallization front in the furnace to 10.04℃ / cm.

[0091] In this scenario, due to the actual growth rate exceeding the limit, the deviation value (v) g,target -v g (t) turns negative. According to the formula adjustment, the system performs a deceleration and pull-up (v) adjustment. new <v current And simultaneously slow down the temperature gradient (G) new <G current From a physical perspective, reducing the temperature gradient G directly weakens the supercooling driving force at the melt interface, and its growth-suppressing effect perfectly offsets the tendency for crystal thickening caused by slowing down the pulling speed v. The synergistic effect of the bivariate negative feedback allows the rapidly increasing crystallization flow rate to smoothly and safely return to the target steady state, successfully blocking the damage to the coherent bicrystalline interface caused by the large amount of latent heat of crystallization released too quickly, and effectively preventing the distortion of coherent grain boundaries and the generation of microcracks.

[0092] After crystal extraction and testing, the crystals showed extremely high consistency in both external dimensions and internal grain boundary straightness.

[0093] Example 3

[0094] It is basically the same as Example 1, except that:

[0095] In step four, during the twin crystal pulling process, a sudden and instantaneous drop in the heating power of the simulated high-temperature furnace caused a sharp decrease in the crystallization front temperature, resulting in a rapid and abnormal change in the actual crystallization rate. g (t) = 1.9 mm / h. After detecting this extreme deviation, the control system retrieves the current real-time process parameters: current lifting speed v current =1.45mm / h, current crystallization front temperature gradient G current =10.02℃ / cm. The control system automatically performs the following compensation calculation:

[0096]

[0097]

[0098] Based on the calculation results, the control system immediately reduced the operating speed of the lifting mechanism to 1.41 mm / h, and at the same time fine-tuned the heating power ratio to steadily reduce the temperature gradient at the crystallization front in the furnace to 10.00℃ / cm.

[0099] Due to fluctuations in the heating power of the high-temperature furnace leading to increased supercooling, the system dynamically adjusts the temperature gradient in real time to rapidly curb the drastic solidification trend of the melt. Through micro-frequency iterations over several consecutive time intervals Δt, the system successfully pulls the crystal back from the edge of a malignant explosive growth rate to the target crystallization rate without manual intervention. The dynamic adjustment process exhibits a smooth waveform, effectively avoiding the drastic consequences of sudden changes in pulling speed caused by traditional single-variable control, which could lead to severe bending of the solid-liquid interface and subsequent degradation of bicrystalline crystals into monocrystalline crystals. This fully demonstrates the core technological contribution of the control formula of this invention to maintaining coherent grain boundaries in bicrystalline crystals when dealing with extreme environmental disturbances.

[0100] After crystal extraction and testing, the obtained strontium tantalum aluminate bicrystalline crystals showed no thermal shock defects and excellent grain boundary integrity.

[0101] Example 4

[0102] It is basically the same as Example 1, except that:

[0103] In step three, the adjustment coefficient is set to the maximum gain limit, i.e., the speed adjustment coefficient k. v =0.18, temperature gradient adjustment coefficient k G =0.09.

[0104] In step four, during the twin crystal pulling process, a sudden, instantaneous power spike occurred in the simulated high-temperature furnace heating control loop, causing a sharp rise in the crystallization front temperature. The melt overheating led to an upward melting-back trend at the solid-liquid interface, resulting in a sharp drop in the actual crystallization flow rate. The actual growth rate v was then measured. g (t) = 0.6 mm / h. After detecting this extreme negative deviation, the control system retrieves the current real-time process parameters: current lifting speed v current =1.42mm / h, current crystallization front temperature gradient G current =10.02℃ / cm. The control system automatically performs the following compensation calculation:

[0105]

[0106]

[0107] Based on the calculation results, the control system immediately increased the operating speed of the lifting mechanism to 1.582 mm / h, and at the same time significantly adjusted the heating power ratio to steadily increase the temperature gradient at the solid-liquid interface front to 10.101℃ / cm.

[0108] In this scenario, due to sudden external overheating causing a severe deficiency in the crystallization rate, the deviation value (v) g,target -v g (t) exhibits a very large positive value. The system introduces a large gain coefficient k v =0.18, k G =0.09 triggered a highly sensitive emergency adjustment: on the one hand, the lifting speed v was increased. new This forces the solid-liquid interface of the crystal to detach upwards from the high-temperature melt core region, preventing microscopic melting at the crystal root; on the other hand, it significantly increases the temperature gradient G at the crystallization front. new By establishing an extremely strong local heat transfer cooling driving force, external overheating disturbances are forcibly countered, forcing the crystallization front to regenerate solidification flow. This is achieved through several consecutive time intervals. With high gain and rapid iteration, the system successfully adjusted the crystal from the brink of melting and ablation to the target crystallization rate of 1.5 mm / h without introducing manual intervention. Post-crystal testing revealed that the obtained strontium-tantalum-lanthanum aluminate twin crystals showed no distortion defects caused by thermal ablation in terms of dimensional appearance and internal grain boundary straightness, demonstrating excellent grain boundary coherence integrity.

[0109] Based on the above embodiments, it can be seen that the present invention calculates the actual crystallization rate v of the crystal in real time using high-precision weighing data. g (t), and dynamically adjust the process parameters accordingly to offset the fluctuations in the crystallization state and maintain the stability of the bicrystalline interface during the constant diameter growth stage.

[0110] Specifically, when the crystal growth process is disturbed, resulting in a slower actual crystallization rate, the control system synchronously increases the pulling speed v based on the positive deviation. new Temperature gradient G at the crystallization front new The enhanced interfacial solidification driving force guides the crystal growth rate to quickly recover to the preset target growth rate v. g,target This avoids excessive local thickening of the crystals. When faced with localized supercooling caused by thermal convection in the mid-to-late stages of the melt, leading to a sudden and excessive increase in the actual crystallization rate, the system calculates a negative deviation, adjusts the pulling speed accordingly, and smoothly reduces the temperature gradient at the crystallization front. The reduced temperature gradient weakens the supercooling driving force at the interface, counteracting the tendency for crystal thickening caused by deceleration during pulling. This allows the excessively rapid crystallization rate to safely return to the target steady state and prevents the explosive latent heat of crystallization from damaging the bicrystalline interface. In the face of extreme external disturbances such as a sudden drop in heating power causing a sharp drop in the temperature field, or a sudden increase in power causing the solid-liquid interface to melt back, the system can dynamically adjust the temperature across several consecutive sampling time intervals. Rapid micro-frequency iterative compensation is performed internally, and the abnormal solidification or melting trend of the melt is suppressed by significantly adjusting the temperature gradient.

[0111] This invention effectively avoids the consequences of the bicrystalline structure degenerating into a single crystal or grain boundary fracture caused by the sudden change in pulling speed due to the bivariate dynamic coordinated control of the speed and temperature gradient. This is achieved by the traditional single-variable control.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for promoting the growth of strontium tantalum aluminate twins, characterized in that, Includes the following steps: S1. After the raw materials are mixed evenly, they are placed in a crucible and then sent into a high-temperature furnace for high-temperature melting. S2. Introduce a twin seed crystal and use an upward pulling method to control the twin seed crystal to be slowly pulled up from the molten raw material in order to pull the twin crystal. S3. During the upward growth process, the weight data of the growing bicrystalline crystal is collected in real time using a weighing device. S4. Based on the weight change trend of the twin crystal, dynamically and synchronously adjust the pulling speed of the pulling device and the temperature gradient of the high-temperature furnace to maintain the coherent and stable growth of the twin crystal interface. S5. After growth is complete, reduce the temperature and pressure inside the furnace cavity to remove the grown strontium tantalum lanthanum aluminate twin crystals.

2. The method for promoting the growth of strontium tantalum aluminate twins according to claim 1, characterized in that, The raw materials include lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide; The mass ratio of lanthanum oxide, aluminum oxide, strontium carbonate, and tantalum oxide is as follows: lanthanum oxide 15.0–26.0 parts, aluminum oxide 12.0–16.0 parts, strontium carbonate 38.0–50.0 parts, and tantalum oxide 28.0–38.0 parts.

3. The method for promoting the growth of strontium tantalum aluminate twins according to claim 1, characterized in that, In step S2, the initial pulling speed of the pulled bicrystalline crystal is controlled at 0.3 mm / h to 0.5 mm / h; In step S4, the total range of the bicrystalline crystal pulling speed during the dynamic control process is controlled within 0.1 mm / h to 2.0 mm / h.

4. The method for promoting the growth of strontium tantalum aluminate twins according to claim 1, characterized in that, In step S2, the initial temperature gradient of the high-temperature furnace is controlled between 5℃ / cm and 20℃ / cm; The melting temperature of the high-temperature furnace is controlled between 1800℃ and 2200℃.

5. The method for promoting the growth of strontium tantalum aluminate twins according to claim 1, characterized in that, The process of pulling the bicrystalline material is carried out under a protective atmosphere of inert gas.

6. The method for promoting the growth of strontium tantalum aluminate twins according to claim 1, characterized in that, In step S4, the dynamic control step specifically includes the following sub-steps: K1, Data Acquisition: Data is acquired at set time intervals Δt, showing the growth of the bicrystalline crystal at the current time. The real-time mass m(t) at time t and the mass m(t+Δt) at the next time t; K2. Rate Calculation: Calculate the current actual crystal growth rate v based on the mass change within adjacent time nodes. g (t); K3, Deviation Confirmation: The actual crystal growth rate v g (t) and the preset target growth rate v g,target Compare the values ​​to determine the growth rate deviation. K4. Parameter Compensation: Based on the growth rate deviation value, the corrected lifting speed and the corrected temperature gradient are calculated synchronously through the automated feedback control system, and real-time adjustments are performed.

7. The method for promoting the growth of strontium tantalum aluminate twins according to claim 6, characterized in that, In sub-step K2, the actual crystal growth rate v g The formula for calculating (t) is as follows: In the formula: m(t+Δt)-m(t) is the change in the mass of the twin crystals within the time interval Δt; ρ is the density of the bicrystalline crystal; A is the cross-sectional area of ​​the twin crystal.

8. The method for promoting the growth of strontium tantalum aluminate twins according to claim 6, characterized in that, In sub-step K4, the corrected lifting speed is calculated using the following speed adjustment formula: In the formula: v new The corrected lifting speed; v current The current lifting speed; k v This is the speed adjustment coefficient.

9. The method for promoting the growth of strontium tantalum aluminate twins according to claim 6, characterized in that, In sub-step K4, the dynamic adjustment formula for the corrected temperature gradient is as follows: Where: G new This is the corrected temperature gradient; G current The current temperature gradient; k G This is the temperature gradient adjustment coefficient.

10. A method for promoting the growth of strontium tantalum aluminate twins according to claim 8 or 9, characterized in that: The speed adjustment coefficient k v The value is 0.05 to 0.

2. The temperature gradient adjustment coefficient k G It ranges from 0.01 to 0.1.

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