Synchronous testing system and method for considering magnetic domain evolution process and macroscopic magnetic properties

Abstract

The present invention relates to a synchronous testing system and method for considering the magnetic domain evolution process and macroscopic magnetic properties, including a magneto-optical Kerr microscope, a signal control module, a magnetic field control module, and an electromagnetic sensing module; the testing system combines the magneto-optical Kerr effect and the macroscopic magnetic property testing method, and adds an electromagnetic sensing module including a B probe and an H coil on the platform for the objective lens to observe the sample. The B probe and the H coil are passive sensors, which can avoid the interference of the external magnetic field on the sample during testing. By placing the sensing structure composed of the B probe and the H coil on the sample stage, and then tightly attaching the sample to the B probe and the H coil through a movable buckle, combined with the magneto-optical Kerr technology, the magnetic domain observation and macroscopic rotational magnetic property testing of magnetic materials can be simultaneously carried out on oriented silicon steel materials or nanocrystalline materials in a wider frequency range.

Description

Technical Field

[0001] The present invention relates to a synchronous test system and method for considering the magnetic domain evolution process and macroscopic magnetic properties. Background Art

[0002] Developing high-power transformers with high frequency, high reliability and high power density is an important way to solve the problems of high energy consumption and high material consumption of traditional power-frequency equipment. Reducing the losses of magnetic components has a decisive impact on improving the efficiency and power density of high-frequency transformers. The intrinsic magnetic properties of magnetic materials and the dynamic magnetic properties under external excitation conditions are crucial for the core structure design, loss calculation and improvement of the service performance of high-frequency transformers. Studying the intrinsic magnetic properties, both internal and external, of materials from the perspective of microscopic magnetization mechanism helps to model the material properties and trace the physical mechanism of thermal effects. Therefore, it is necessary to simultaneously observe through a magnetic domain observation system and a macroscopic magnetic property test system to establish a magnetic property model and loss calculation method supported by micromagnetics theory.

[0003] Traditional macroscopic loss tests and microscopic magnetic domain observations of magnetic materials are two independent devices and cannot synchronously test the microscopic magnetic domain motion and dynamic magnetic properties of magnetic materials. The literature "Shi Minxia, Hou Zhiqiang, Zhang Qian, Qiu Aici, Li Junhao. Design and Optimization of a Vector Magnetic Property Measurement System for Electrical Steel Sheets [J]. Journal of Xi'an Jiaotong University, 2019, 53(02): 88-95." uses a square sample four-pole excitation device and can only test the macroscopic magnetic properties of the sample in a certain direction. If testing the anisotropy of the sample, samples at different angles need to be prepared, and the preparation process is cumbersome and time-consuming. Moreover, even for samples of the same batch, there will be slight differences in their magnetic properties, which will cause certain test errors. The patent "Zhou Chao, Xu Jia, Jia Mengwen, Wu Yizheng. A Method for Measuring the Antiferromagnetic Domain Distribution Using the Magneto-Optical Kerr Effect [P]. Shanghai: CN108710090A, 2018-10-26." uses a magneto-optical Kerr microscope with a function of collecting digital images to process the observed images and can only observe microscopic magnetic domains and cannot simultaneously conduct macroscopic magnetic property tests. This to a certain extent affects the accurate modeling of the magnetic properties of magnetic materials, limits the analysis of the magnetic properties of magnetic materials, leads to deviations in the analysis, and thus it is very difficult to play a good guiding role in modeling the actual magnetic material properties. Therefore, it is very necessary to design a synchronous test system that considers the magnetic domain evolution process and macroscopic magnetic properties to more accurately simultaneously conduct magnetic domain observation and macroscopic magnetic property test of magnetic materials, so as to establish a more accurate magnetic property model and loss calculation method. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to design a synchronous test system and method that takes into account the magnetic domain evolution process and macroscopic magnetic properties. This test system combines the magneto-optical Kerr effect and macroscopic magnetic property test methods. An electromagnetic sensing module containing a B probe and an H coil is added to the platform for observing the sample by the objective lens. The B probe and the H coil are passive sensors, which can avoid the interference of the external magnetic field on the sample during the test. By placing the sensing structure composed of the B probe and the H coil on the sample stage, and then closely attaching the sample to the B probe and the H coil through a movable buckle, combined with the magneto-optical Kerr technology, it is possible to simultaneously perform magnetic domain observation and macroscopic rotational magnetic property test on oriented silicon steel materials or nanocrystalline materials in a wider frequency range. In addition, the anisotropy of the sample can also be observed, which is beneficial to more accurately construct the magnetic property construction and loss calculation models of magnetic materials from a physical level.

[0005] The technical solution adopted by the present invention to solve the above technical problem is as follows:

[0006] A synchronous test system that takes into account the magnetic domain evolution process and macroscopic magnetic properties, including a magneto-optical Kerr microscope, a signal control module, a magnetic field control module, and an electromagnetic sensing module; characterized in that the magnetic field control module includes a circular two-dimensional excitation device 10 and a magnetic shielding device 24. The circular two-dimensional excitation device 10 includes an excitation magnetic yoke and a two-phase excitation winding. The excitation winding is connected to the signal control module. The horizontal central axis of the excitation magnetic yoke is higher than the horizontal central axis of the sample stage 11 of the magneto-optical Kerr microscope, and the excitation magnetic yoke is located outside the sample stage. The excitation magnetic yoke is a ring-shaped serrated structure; the magnetic shielding device 24 is used to prevent the interference of the leakage magnetic flux of the excitation magnetic yoke and is installed on the periphery of the sample area. The shielding area of the magnetic shielding device is the test position and is placed on the sample for support;

[0007] A plurality of coaxially arranged annular discs with different inner diameters are provided between the excitation magnetic yoke and the base 8 of the magneto-optical Kerr microscope to support the excitation magnetic yoke. The thickness of the excitation magnetic yoke is greater than the thickness of the sample, and when installed, the horizontal central axes of the excitation magnetic yoke and the sample are on the same horizontal plane;

[0008] The electromagnetic sensing module is used to measure the magnetic induction intensity B of the sample by the probe method and measure the magnetic field intensity H by the tunneling magnetoresistance linear magnetic field sensing element. The electromagnetic sensing module is fixedly installed above the sample stage 11 and includes a sensing platform 20, four B probes 15, an H coil 16, a spring 14, a slider 17, a slide rail 18, a buckle 19, and an adjustable buckle platform 21;

[0009] The four B probes 15 are evenly arranged around the H coil 16 on the sensing platform 20. The distance between two opposite B probes is 3-5 mm of the sample diameter. The length and width of the H coil 16 are 2-4 mm. Within the elastic range of the spring, the sample can not only contact the B probes but also closely contact the H coil. The four B probes are respectively installed on the sensing platform through springs 14, and the H coil 16 is installed at the center of the sensing platform;

[0010] The adjustable buckle platform 21 is fixed on the sample stage. A slide rail 18 is fixedly installed on the adjustable buckle platform 21. The slide rail 18 is concave-shaped, including a horizontal section 182 and vertical sections 181 vertically installed at both ends of the horizontal section. The horizontal section is fixedly installed on the adjustable buckle platform 22. Both ends of the vertical section are respectively connected to the inner side of the buckle 19 through a slider 17, so that the whole buckle 19 can move up and down on the vertical section;

[0011] The buckle 19 includes a horizontal area connecting piece 191 and two vertical clamping pieces 192 perpendicular to the horizontal area connecting piece. The vertical clamping pieces 192 are both located outside the corresponding vertical sections of the slide rail 18. A sharp corner is provided on the inner side of the vertical clamping piece, and the sharp corner is used to limit the upper position of the sample; The lower part of the sensing platform 20 is installed on the horizontal section 182 of the slide rail 18 through a slider 17, and the sensing platform 20 can move left and right on the horizontal section; After the sample is fixed, the sample can just tightly fit with the B probes and the H coil;

[0012] The distance between the two vertical clamping pieces of the buckle 19 is slightly smaller than the inner diameter of the excitation yoke and not less than the diameter of the sample.

[0013] The present invention also protects a synchronous test method considering the magnetic domain evolution process and macroscopic magnetic properties. This test method uses the above test system. The process of this test method is as follows:

[0014] Step 1: Place the sample to be tested laterally on the B probes, move the buckle downward, so that the sample tightly fits with the B probes and the H coil, and then align the sample with the horizontal central axis of the circular two-dimensional excitation device and on the same horizontal plane through the fine-tuning displacement platform; Adjust the lens barrel assembly to further adjust the observation position of the sample to be tested so that the sample is in the center of the objective lens, and determine the test position of the sample;

[0015] Step 2: Move the sensing platform to the test position so that the sensing platform is directly below the sample test position;

[0016] Step 3: Place the magnetic shielding device 24 directly above the sample test position;

[0017] Step 4: Connect the incoming and outgoing terminals of the two-phase excitation winding;

[0018] Step 5: Measure the inductance at a specific frequency and with a specific connection mode of the exciting winding using an impedance analyzer, calculate the resonant capacitance value, and match it with a high-voltage-resistant non-inductive capacitor;

[0019] Step 6: Apply sinusoidal alternating currents with a phase difference of 90 degrees to the two-phase exciting windings respectively. Send an alternating exciting signal through the computer 4, and after amplification by the power amplification unit 5, control the amplitude and phase of the sinusoidal alternating current in the exciting winding to form a rotating magnetic field in the plane where the sample to be measured is located;

[0020] Step 7: Observe the waveforms of the magnetic flux density and magnetic field strength, collect the voltage signals between two relative B probes, detect the induced voltage signals of the H coil, and at the same time observe the mesoscopic magnetic domain changes of the sample by changing the magnification of the magneto-optical Kerr microscope barrel. Store the magnetic property data and the corresponding mesoscopic magnetic domain image data, and increase the amplitude of the exciting voltage until the sample to be measured is saturated;

[0021] Step 8: After observing magnetic saturation, slowly reduce the exciting signal to demagnetize the sample to be measured;

[0022] Step 9: Repeat Step 5, Step 6, Step 7, and Step 8 until the magnetic property detection under the required frequency and exciting mode is completed, obtaining the trajectory diagrams of the magnetic induction intensity and magnetic field strength of the sample and the mesoscopic magnetic domain changes under different frequencies and different exciting currents, and realizing the synchronous test of the magnetic domain evolution process and the macroscopic magnetic properties.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The present invention combines the macroscopic magnetic property measurement system with the microscopic magnetic domain observation system, thereby realizing the multi-functional observation of the microscopic magnetic domain and the macroscopic magnetic properties at the same point of the sample, and more accurately observing the performance of the magnetic material.

[0025] (2) The present invention uses a circular two-dimensional exciting device to replace the original exciting device arranged horizontally and vertically, which can form a spatial rotating magnetic field, allowing the development of two-dimensional rotating magnetic property experiments. At the same time, without replacing the sample, by rotating the sample stage, the anisotropy of the material can be tested, eliminating the material property differences between different samples and the test errors caused by replacing the sample, improving the test accuracy. Such a setting can achieve that when performing the test, the optical path is directed to the sample and the rotating magnetic measurement of the sample is realized.

[0026] (3) In the present invention, by using the nested structure composed of a B probe and an H coil, by measuring the current and voltage signals, the interference of the external magnetic field can be avoided, improving the test accuracy; at the same time, a circular two-dimensional exciting device composed of a circular exciting yoke and a winding is used, which can provide a rotating magnetic field to test the rotating magnetic properties of the sample and realize tests at different angles.

[0027] (4) The present invention is equipped with a magnetic shielding device, which is placed around the sample. The magnetic shielding height can be higher than the yoke height, which can minimize the influence of the leakage magnetic flux of the yoke on the magnetic measurement of the sample and improve the test accuracy.

[0028] (5) The present invention uses the B-probe measurement method to replace the punching method for measuring the magnetic field intensity, reduces the influence of edge effects on the test accuracy, makes the magnetic field in the test area more uniform, and can avoid the damage of the magnetic properties of the material caused by punching.

[0029] (6) In the electromagnetic sensing module of the present invention, the adjustable buckle standardizes the position of the sample when the sample is placed on the sensing device and makes the sample closely fit on the sensing device. In addition, when the B-probe is squeezed, due to the action of the internal spring, it can ensure that the probe and the sample are in close contact through four points without causing a particularly large squeezing force on the four points of the sample, so as to prevent the sample from deforming.

[0030] (7) The movable sensing platform in the electromagnetic sensing module of the present invention can ensure that when observing different positions of the sample under the microscope, the sensing platform can also move to the same position to more accurately observe the magnetic properties of the magnetic material.

[0031] (8) The synchronous test system of the present invention considering the magnetic domain evolution process and the macroscopic magnetic properties can more accurately perform magnetic domain observation and macroscopic rotational magnetic property testing on grain-oriented silicon steel materials or nanocrystalline materials simultaneously in a wider frequency range. It has a wider application range and can analyze the anisotropy of the material. Preferably, a nanocrystalline material with the model number 1K107B is used as the yoke in the circular two-dimensional excitation device, which can further expand the testable frequency range and is conducive to completing the test at high frequencies. Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the overall structural connection of the synchronous test system of the present invention considering the magnetic domain evolution process and the macroscopic magnetic properties;

[0033] Figure 2 It is a schematic diagram of the overall installation position structure of the magneto-optical Kerr microscope, the magnetic field control module, and the electromagnetic sensing module of the present invention;

[0034] Figure 3 It is a three-dimensional structural schematic diagram of the electromagnetic sensing module of the present invention;

[0035] Figure 4 It is a three-dimensional structural schematic diagram of the sample support platform of the present invention;

[0036] Figure 5 It is a three-dimensional structural schematic diagram of the magnetic shielding device 24 of the present invention;

[0037] In the figure, 1 is a detector; 2 is a differential amplifier; 3 is an NI acquisition card; 4 is a calculator control program; 5 is a power amplification unit; 6 is a water-cooled resistor; 7 is a matching capacitor; 8 is a base; 9 is a displacement platform; 10 is a circular two-dimensional excitation device; 11 is a sample stage; 12 is an optical path system; 13 is a lens barrel assembly; 14 is a spring; 15 is a B probe; 16 is an H coil; 17 is a slider; 18 is a slide rail; 19 is a buckle; 20 is a sensing platform; 21 is an adjustable buckle platform; 22 is a sample support platform; 23 is a support member; 24 is a magnetic shielding device; 181 is a vertical section, 182 is a horizontal section, 191 is a horizontal area connecting member, and 192 is a vertical clamping member. Detailed implementation manners

[0038] The following are specific embodiments of the present invention. The specific embodiments are only used for further detailed description of the present invention and do not limit the protection scope of this application.

[0039] A synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties in the present invention, the system includes a magneto-optical Kerr microscope, a signal control module, a magnetic field control module and an electromagnetic sensing module.

[0040] The magneto-optical Kerr microscope includes an optical path system 12, a lens barrel assembly 13, a base 8, a displacement platform 9 and a sample stage 11. The sample stage 11 is arranged below the lens barrel assembly 13. The sample stage is fixed on the displacement platform 9. The displacement platform (the displacement platform can be an xyz movement module) can move the sample stage in the left-right, front-back directions. The base 8 and the displacement platform are connected by a rotating shaft, so that the displacement platform can perform a rotational movement; the optical path system 12 and the lens barrel assembly 13 are used to provide an optical path and an observation path for mesoscopic magnetic domain observation.

[0041] The signal control module is used to provide excitation to the magnetic field control module, and includes a detector 1, a differential amplifier 2, an NI acquisition card 3, a computer, a power amplification unit 5, a water-cooled resistor 6, and a matching capacitor 7 connected in sequence. The signal collected by the detector 1 is amplified by the differential amplifier 2 and then enters the NI acquisition card 3 for processing. After obtaining the sensing signal, it enters the computer. The computer issues a corresponding control signal to the power amplifier 5 according to the sensing signal. The control signal issued by the power amplifier 5 acts on the magnetic field control module through the water-cooled resistor 6 and the matching capacitor 7 to control the magnetic field, so as to achieve a closed-loop effect; a labview test platform is loaded in the computer 4;

[0042] The matching capacitor 7 is connected to the excitation winding of the circular two-dimensional excitation device 10 of the magnetic field control module, and different capacitance values are used to compensate the reactive power according to different frequency bands;

[0043] The magnetic field control module includes a circular two-dimensional excitation device 10 and a magnetic shielding device 24. The circular two-dimensional excitation device 10 includes an excitation yoke and a two-phase excitation winding. The excitation winding is connected to a matching capacitor 7. The excitation yoke can be made of a nanocrystalline material with the model number 1K107B. The horizontal central axis of the nanocrystalline excitation yoke is slightly higher than the horizontal central axis of the sample stage 11, and the nanocrystalline excitation yoke is located outside the sample stage. The excitation yoke is of an annular sawtooth structure. The magnetic shielding device 24 is used to prevent the interference of the leakage magnetic flux of the excitation yoke and is installed around the area where the sample is located. The magnetic shielding device is a hexagonal prism formed by enclosing six flat cuboid electromagnetic shielding materials with a length of 3 mm, a thickness of 1 mm, and a height of 10 mm. It is directly placed above the sample. The inner diameter of the magnetic shielding device is larger than the diameter of the circumscribed circle where the four B probes are located. The shielding area is the sample test position and is placed on the sample for support.

[0044] A plurality of coaxially arranged annular discs with different inner diameters are provided between the excitation yoke, the base 8, and the displacement platform 9 for supporting the excitation yoke. The inner diameter of the excitation yoke is slightly larger than the diameter of the sample, and the thickness of the excitation yoke is greater than the thickness of the sample. When installed, their horizontal central axes are on the same horizontal plane. If the sample is located exactly in the middle of the excitation yoke, the thickness of the yoke is 5 mm, the thickness of the sample is 2 mm, and the position with a sample thickness of 1 mm is at the same height as the position with a yoke thickness of 2.5 mm.

[0045] The electromagnetic sensing module is used to measure the magnetic induction intensity B of the sample by the probe method and measure the magnetic field intensity H by using a tunneling magnetoresistance (TMR) linear magnetic field sensing element, realizing the integration of the sensing system. The electromagnetic sensing module is fixedly installed above the sample stage 11 and includes a sensing platform 20, four B probes 15, an H coil 16, a spring 14, a slider 17, a slide rail 18, a buckle 19, an adjustable buckle platform 21, a sample support platform 22, and a support member 23.

[0046] The four B probes 15 are evenly arranged on the sensing platform 20 around the H coil 16. The distance between two opposite B probes is 3 mm. The length and width of the H coil 16 are both 2 mm. Within the elastic range of the spring, the sample can be in contact with both the B probes and the H coil tightly. The height of the H coil is not less than the height of the B probes when the spring is compressed to the shortest state. The four B probes are respectively installed on the sensing platform through the spring 14, and the H coil 16 is installed at the center of the sensing platform.

[0047] The sample support platform 22 is horizontally aligned with the upper plane of the H coil. When the sample, B probe, and H coil are in contact, for test samples with a thickness less than a preset value, the sample support platform supports the sample to ensure that the entire plane of the sample is always in the same plane. The support member 23 supports the sample support platform. The sample support platform 22 is fixed on the adjustable buckle platform 21 through the support member and does not interfere with the movement of the sensing platform.

[0048] The adjustable buckle platform 21 is fixed on the sample stage. A slide rail 18 is fixedly installed on the adjustable buckle platform 21. The slide rail 18 is concave-shaped and includes a horizontal section 182 and vertical sections 181 vertically installed at both ends of the horizontal section. The horizontal section is fixedly installed on the adjustable buckle platform 22. Both ends of the vertical section are respectively connected to the inner side of the buckle 19 through a slider 17, so that the whole buckle 19 can move up and down on the vertical section.

[0049] The buckle 19 includes a horizontal area connecting member 191 and two vertical clamping members 192 perpendicular to the horizontal area connecting member. The vertical clamping members 192 are both located outside the corresponding vertical sections of the slide rail 18. A sharp corner is provided on the inner side of the vertical clamping member, and the sharp corner is used to limit the upper position of the sample, that is, the upper limit. The lower part of the sensing platform 20 is installed on the horizontal section 182 of the slide rail 18 through a slider 17 and can move left and right on the horizontal section. The lower limit of the sample is determined by the height of the B probe and the H coil. After the sample is fixed, the sample can just fit tightly with the B probe and the H coil. The setting of the horizontal area connecting member 191 enables the left and right sides of the sample to move up and down simultaneously.

[0050] The distance between the two vertical clamping members of the buckle 19 is slightly smaller than the inner diameter of the excitation yoke and not less than the diameter of the sample. The distance between the two sharp corners on the buckle is 0.4 mm smaller than the diameter of the sample.

[0051] The thickness of the sample varies according to the material type. The material of the sample and the excitation yoke can be the same or different. The sample material can be nanocrystalline or silicon steel sheet, etc. If the sample material is nanocrystalline, the typical thickness is within 20 μm, and at this time, a sample support platform needs to be set. If it is oriented silicon steel sheet, the typical thickness is about 0.27 mm.

[0052] The size of the sample is larger than the size of the sensing platform. The shape can be a circular sample. The sample is fixed in the center of the sample stage and is located above the B probe and the H coil.

[0053] This application adds an adjustable buckle platform. The buckle 19 can move up and down on the vertical section 181 of the slide rail 18, enabling the sample to closely fit the H coil on the sensing platform. At the same time, the sensing platform can also move left and right along the horizontal section of the slide rail 18, ensuring that while changing the sample observation area, the sensing platform can be moved to the same position as the observation area, guaranteeing the simultaneous measurement of the magnetic properties and magnetic domain observation of the sample at the same point.

[0054] When placing the sample, first slide the buckle 19 upward to raise the position where the sharp corner of the buckle is located. Insert the sample from the side between the B probe and the sharp corner and let it freely fall to be supported by the four vertices of the four B probes. Then slide the buckle 19 downward. The spring is at the lower part of the B probe. Due to the elasticity of the spring, during the process of adjusting the buckle downward, the B probe compresses the spring and moves downward until the sample contacts the upper surface of the H coil. Stop the downward movement of the buckle. Determine that the upper surface of the H coil contacts the sample and the B probe is flush with the upper end surface of the H coil. At this time, the sample, the B probe 15, and the H coil 16 are closely fitted, thus ensuring the accuracy of the measurement.

[0055] Since the mesoscopic magnetic domain observation can only be carried out in a specific small area, the combined structure of the B probe and the H coil and the buckle structure of the present invention can meet the requirement of simultaneous mesoscopic magnetic domain observation and macroscopic magnetic property test at the same point, ensuring that the areas for mesoscopic magnetic domain observation and macroscopic magnetic property test are the same area.

[0056] The present invention uses an electromagnetic sensing module fixed on the sample stage to achieve simultaneous microscopic magnetic domain observation and macroscopic magnetic property test; uses a circular two-dimensional excitation device 10, which can not only enable the light path to reach the sample test area, but also, without replacing the sample, test different directions of the sample by rotating the displacement platform 9, thereby achieving the purpose of testing the anisotropy of the material, eliminating test errors, and ensuring the test accuracy; preferably uses nanocrystalline as the excitation magnetic yoke to improve the test frequency of the circular two-dimensional excitation device; because the magnetic domain change of nanocrystalline is repeatable during the magnetization process and the research on nanocrystalline at high frequencies is very meaningful, in order to obtain accurate magnetic domain images at higher frequencies, the present invention adopts a stroboscopic technique. Images are collected sequentially through the optical path system at a pre-calculated time interval to form a continuous image of an entire cycle. By capturing several photos at a certain time interval and finally connecting the images, an image of an entire cycle can be obtained through the connected images; by adjusting the position of the sample in the height direction through the displacement platform, the sample can be finely adjusted to be focused and present a clear image, improving the magnetic domain observation accuracy.

[0057] The present invention provides a synchronous test method considering the magnetic domain evolution process and macroscopic magnetic properties. The process of this test method is as follows:

[0058] Step 1: Place the sample to be tested laterally on the B probe, move the buckle downward so that the sample fits tightly with the B probe and the H coil, and then align the sample with the horizontal central axis of the circular two-dimensional excitation device and on the same horizontal plane by fine-tuning the displacement platform; adjust the lens barrel assembly to further adjust the observation position of the sample to be tested so that the sample is at the center of the objective lens, and determine the test position of the sample;

[0059] Step 2: Move the sensing platform to the test position so that the sensing platform is directly below the sample test position;

[0060] Step 3: Place the magnetic shielding device 24 directly above the sample test position;

[0061] Step 4: Connect the incoming and outgoing terminals of the two-phase excitation winding;

[0062] Step 5: Measure the inductance under specific frequencies and excitation winding connection methods with an impedance analyzer, calculate the resonant capacitance value, and use non-inductive capacitors with high voltage resistance for matching to reduce the excitation current in the system;

[0063] Step 6: Pass sinusoidal alternating currents with a phase difference of 90 degrees through the two-phase excitation winding respectively. Connect the computer 4 to the power amplifier unit 5 to send out an alternating excitation signal. After being amplified by the power amplifier unit 5, control the amplitude and phase of the sinusoidal alternating current in the excitation winding to form a rotating magnetic field in the plane where the sample to be tested is located;

[0064] Step 7: Observe the waveforms of the magnetic flux density and magnetic field strength, collect the voltage signals between two relative B probes, detect the induced voltage signals of the H coil, and at the same time observe the changes in the mesoscopic magnetic domains of the sample by changing the magnification of the lens barrel of the magneto-optical Kerr microscope, store the magnetic characteristic data and the corresponding mesoscopic magnetic domain image data, and increase the excitation voltage amplitude until the sample to be tested is saturated;

[0065] Step 8: After observing magnetic saturation, slowly reduce the excitation signal to demagnetize the sample to be tested;

[0066] Step 9: Repeat Step 5, Step 6, Step 7, and Step 8 until the magnetic characteristic detection under the required frequencies and excitation methods is completed, obtain the trajectory diagrams of the magnetic induction intensity and magnetic field strength of the sample and the changes in the mesoscopic magnetic domains under different frequencies and different excitation currents, and then analyze the data to obtain the loss model to calculate the loss, realizing the synchronous test of the magnetic domain evolution process and the macroscopic magnetic characteristics.

[0067] The present invention can perform dynamic rotational magnetic property tests (at the same point) while observing the evolution of magnetic domains, and can also observe the anisotropy of the sample. The present invention adjusts the layout of the sensing structure, and makes the sample and the sensor fit more closely by adding an adjustable snap platform. At the same time, considering that when performing mesoscopic magnetic domain observation, the optical path needs to be led to the sample, a conventional excitation device will block the optical path. In addition, in order to better test the anisotropy of the sample, the excitation device is designed. A circular two-dimensional excitation device is used to test the rotational magnetic properties of the sample, and a magnetic shield is added around the sample to effectively prevent the leakage magnetic flux of the magnetic yoke from interfering.

[0068] Matters not described in the present invention are applicable to the prior art.

Claims

1. A synchronous testing system that takes into account the magnetic domain evolution process and macroscopic magnetic properties, comprising a magneto-optical Kerr microscope, a signal control module, a magnetic field control module, and an electromagnetic sensing module; Characterized in that, The magnetic field control module includes a circular two-dimensional excitation device and a magnetic shielding device. The circular two-dimensional excitation device includes an excitation magnetic yoke and a two-phase excitation winding. The excitation winding is connected to the signal control module. The horizontal central axis of the excitation magnetic yoke is higher than the horizontal central axis of the sample stage of the magneto-optical Kerr microscope, and the excitation magnetic yoke is located outside the sample stage. The excitation magnetic yoke is of an annular sawtooth structure; The magnetic shielding device is used to prevent the interference of the leakage magnetic flux of the excitation magnetic yoke, and is installed around the area where the sample is located. The shielding area of the magnetic shielding device is the test position and is placed on the sample for support; A plurality of coaxially arranged annular discs with different inner diameters are provided between the excitation magnetic yoke and the base of the magneto-optical Kerr microscope for supporting the excitation magnetic yoke. The thickness of the excitation magnetic yoke is greater than the thickness of the sample, and when installed, the horizontal central axes of the excitation magnetic yoke and the sample are on the same horizontal plane; The electromagnetic sensing module is used to measure the magnetic induction intensity B of the sample by the probe method and measure the magnetic field intensity H by the tunneling magnetoresistance linear magnetic field sensing element. The electromagnetic sensing module is fixedly installed above the sample stage and includes a sensing platform, four B probes, an H coil, springs, sliders, slide rails, buckles, and an adjustable buckle platform; The four B probes are evenly arranged around the H coil on the sensing platform. The distance between two opposite B probes is 3-5 mm of the sample diameter. The length and width of the H coil are 2-4 mm. Within the elastic range of the spring, the sample can not only contact the B probes but also be in close contact with the H coil. The four B probes are respectively installed on the sensing platform through springs, and the H coil is installed at the center of the sensing platform; The adjustable buckle platform is fixed on the sample stage, and a slide rail is fixedly installed on the adjustable buckle platform. The slide rail is of a concave shape, including a horizontal section and vertical sections vertically installed at both ends of the horizontal section. The horizontal section is fixedly installed on the adjustable buckle platform, and both ends of the vertical section are respectively connected to the inner side of the buckle through a slider, so that the whole buckle can move up and down on the vertical section; The buckle includes a horizontal area connecting piece and two vertical clamping pieces perpendicular to the horizontal area connecting piece. The vertical clamping pieces are both located outside the corresponding vertical sections of the slide rail, and sharp corners are provided on the inner sides of the vertical clamping pieces for restricting the upper position of the sample; The lower part of the sensing platform is installed on the horizontal section of the slide rail through a slider, and the sensing platform can move left and right on the horizontal section; After the sample is fixed, the sample can just fit tightly with the B probes and the H coil; The distance between the two vertical clamping pieces of the buckle is less than the inner diameter of the excitation magnetic yoke and not less than the diameter of the sample.

2. The synchronous testing system according to claim 1 that takes into account the magnetic domain evolution process and macroscopic magnetic properties, Characterized in that, The electromagnetic sensing module further includes a sample support platform, which is horizontally aligned with the upper plane of the H coil. The sample support platform is fixed on the adjustable buckle platform through a support member and does not interfere with the movement of the sensing platform. When the sample is in contact with the B probe and the H coil, for test samples with a thickness less than a preset value, the sample support platform supports the sample to ensure that the entire plane of the sample is always in the same plane.

3. The synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties according to claim 1, characterized in that the sample material is nanocrystalline or silicon steel sheet. When the sample material is nanocrystalline, the typical thickness is within 20 μm. If it is oriented silicon steel sheet, the typical thickness is 0.2 - 0.3 mm; the size of the sample is larger than the size of the sensing platform. A circular sample is used, and the sample is fixed in the exact middle of the sample stage and is located above the B probe and the H coil.

4. The synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties according to claim 1, characterized in that the magnetic shielding device is a hexagonal column formed by six flat cuboid electromagnetic shielding materials with a length of 3 mm, a thickness of 1 mm, and a height of 10 mm, which is directly placed above the sample. The inner diameter of the magnetic shielding device is larger than the diameter of the circumcircle where the four B probes are located.

5. The synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties according to claim 1, characterized in that the distance between the two sharp corners on the buckle is 0.4 mm smaller than the diameter of the sample, the distance between two opposite B probes is 3 mm, and the length and width of the H coil are both 2 mm.

6. The synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties according to claim 1, characterized in that the magneto - optical Kerr microscope includes an optical path system, a lens barrel assembly, a base, a displacement platform, and a sample stage. The sample stage is arranged below the lens barrel assembly and is fixed on the displacement platform. The displacement platform moves the sample stage in the left - right, front - back directions. The base and the displacement platform are connected by a rotating shaft, so that the displacement platform can perform a rotational movement; the optical path system and the lens barrel assembly are used to provide an optical path and an observation path for mesoscopic magnetic domain observation; the signal control module is used to provide excitation to the magnetic field control module, and includes a detector, a differential amplifier, a NI acquisition card, a computer, a power amplifier unit, a water - cooled resistor, and a matching capacitor. The signal collected by the detector is amplified by the differential amplifier and then enters the NI acquisition card for processing. After obtaining the sensing signal, it enters the computer. The computer issues corresponding control signals to the power amplifier according to the sensing signal. The power amplifier issues control signals that act on the magnetic field control module through the water - cooled resistor and the matching capacitor to control the magnetic field, thereby achieving a closed - loop effect; a labview test platform is loaded in the computer; the matching capacitor is connected to the excitation winding of the circular two - dimensional excitation device of the magnetic field control module.

7. The synchronous test system for considering the magnetic domain evolution process and macroscopic magnetic properties according to claim 1, characterized in that When placing the sample, first slide the buckle upward to raise the position where the sharp corner of the buckle is located. Insert the sample laterally between the B probe and the sharp corner, and let it freely fall to be supported by the four vertices of the four B probes. Subsequently, slide the buckle downward. The spring is at the lower part of the B probe. Due to the elasticity of the spring, during the process of sliding the buckle downward, the B probe compresses the spring and moves downward until the sample contacts the upper surface of the H coil. Stop the downward movement of the buckle to determine that the upper surface of the H coil contacts the sample and the B probe is flush with the upper end surface of the H coil. At this time, make the sample, the B probe, and the H coil fit tightly, so as to ensure the accuracy of the measurement.

8. The synchronous test system considering the magnetic domain evolution process and the macroscopic magnetic properties according to claim 1, characterized in that, the exciting magnetic yoke is made of nanocrystalline material.

9. A synchronous test method considering the magnetic domain evolution process and the macroscopic magnetic properties, characterized in that, this test method uses the test system described in claim 6, and the process of this test method is as follows: Step 1: Place the sample to be tested laterally on the B probe, move the buckle downward, so that the sample, the B probe, and the H coil fit tightly, and then align the sample with the horizontal central axis of the circular two-dimensional exciting device and on the same horizontal plane by finely adjusting the displacement platform; Adjust the lens barrel assembly to further adjust the observation position of the sample to be tested so that the sample to be tested is at the exact center of the objective lens, and determine the test position of the sample; Step 2: Move the sensing platform to the test position so that the sensing platform is directly below the test position of the sample; Step 3: Place the magnetic shielding device directly above the test position of the sample; Step 4: Connect the incoming line terminals and the outgoing line terminals of the two-phase exciting windings; Step 5: Measure the inductance under a specific frequency and the connection mode of the exciting winding with an impedance analyzer, calculate the resonant capacitance value, and use a non-inductive capacitor with high voltage resistance for matching; Step 6: Pass sinusoidal alternating currents with a phase difference of 90 degrees in the two-phase exciting windings respectively. Send an alternating exciting signal through a computer, and after amplification by a power amplifier unit, control the amplitude and phase of the sinusoidal alternating current in the exciting winding to form a rotating magnetic field in the plane where the sample to be tested is located; Step 7: Observe the waveforms of the magnetic flux density and the magnetic field strength, collect the voltage signals between the two relatively B probes, detect the induced voltage signal of the H coil, and at the same time observe the mesoscopic magnetic domain changes of the sample by changing the magnification of the lens barrel of the magneto-optical Kerr microscope, store the magnetic property data and the corresponding mesoscopic magnetic domain image data, and increase the exciting voltage amplitude until the sample to be tested is saturated; Step 8: After observing magnetic saturation, slowly reduce the exciting signal to demagnetize the sample to be tested; Step 9: Repeat Step 5, Step 6, Step 7, and Step 8 until the magnetic property detection under the required frequency and exciting mode is completed, and obtain the trajectory diagrams of the magnetic induction intensity and the magnetic field strength of the sample and the mesoscopic magnetic domain changes under different frequencies and different exciting currents, so as to realize the synchronous test of the magnetic domain evolution process and the macroscopic magnetic properties.

10. The test method according to claim 9, characterized in that, this test method can perform dynamic rotating magnetic property tests while observing the magnetic domain evolution at the same point, and can also observe the anisotropy of the sample.

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