Capacitance-based magnetic field device and test system using the same

Abstract

The application discloses a kind of magnetic field devices based on capacitance, comprising: high voltage power supply module of charging to the discharge module of capacitor, after charging, the pulse signal of pulse generator device generates and controls the discharge process of capacitor charging and discharging module, waveform conditioning and protection module, electric signal monitoring and matching module, current commutation module, the magnetic field generation module of the corresponding magnetic field signal of the pulse excitation formed by capacitor discharge.The amplitude of capacitor charging voltage and the pulse width of trigger pulse control pulse signal characteristics, and then control the strength and duration of magnetic field signal, the device can realize controllable intensity high, time domain characteristics good magnetic field signal, while realizing the protection of device, signal monitoring and magnetic field direction change and other functions, solve the problem that current in electromagnetism related experiment is difficult to obtain stable superhigh superfast magnetic field, can provide various types of magnetic field signal, carry out various magnetism and spin electronics research experiment.

Description

A capacitance-based magnetic field device and a testing system using the magnetic field device Technical Field

[0001] This invention belongs to the field of electromagnetics technology, and more specifically, relates to a capacitance-based magnetic field device and a testing system using the magnetic field device. Background Technology

[0002] Currently, researchers in electromagnetism and spintronics, especially in magnetodynamics, are gradually moving away from the traditional stage of qualitative research based on magnetic fields. They are placing higher demands on the experimental capabilities for magnetic domain changes and domain wall motion in the time domain. Common electromagnetic tests primarily rely on altering magnetic environmental factors such as magnetic field dimensions and strength, lacking sufficient experimental means to assess time-domain characteristics. While there are many ways to obtain ultrafast magnetic fields, the mainstream application involves a pulse generator composed of a high-voltage power supply and a high-voltage electronic switch, combined with a magnetic field differential generation module. However, this method suffers from various problems, including low power output, short duration, poor time-domain characteristics, and high maintenance costs.

[0003] Prior art document 1 (Han Xiaotao et al. A High-Stability Flat-Top Pulsed Strong Magnetic Field Generator and Control Method [P]. Hubei: CN109062303A, 2018-12-21.) discloses a magnetic field generator that uses a battery pack as a power supply and connects controllable semiconductor devices in parallel across the magnet. The magnetic field duration of the device and control method described in prior art document 1 is extremely difficult to adjust due to circuit design limitations, and the basic pulse width is on the order of 100ms, which falls far short of the time-domain requirements of many experiments. Furthermore, the low voltage of a single battery cell and the voltage drop over time increase the difficulty of constructing and maintaining the stability of the device.

[0004] The lack of reliable and readily available ultrafast magnetic field acquisition devices in many research institutions and university laboratories hinders the successful conduct of numerous electromagnetic experiments. Research groups face the challenge of purchasing expensive specialized equipment, which strains their R&D funds. Furthermore, the magnetic field generation devices they acquire often fail to produce the desired magnetic field characteristics, significantly compromising the completeness and accuracy of experimental results. This lack of specialized equipment is extremely detrimental to further research in microelectronics fields such as novel spintronic devices and magnetic sensing chip materials. Summary of the Invention

[0005] Addressing the shortcomings of the aforementioned technologies and the lack of related devices, this invention proposes a capacitor-based ultrafast magnetic field device. This device inherits the advantages of fast capacitor discharge speed and high load capacity while also possessing the superior time-domain characteristics of ultra-high-speed MOSFETs and other devices, enabling high-frequency switching. Furthermore, it incorporates rectification and protection circuits, a magnetic field waveform monitoring circuit, and a commutation circuit, forming a complete ultra-high magnetic field experimental setup. This device can generate nanosecond-level high-voltage electrical excitation signals that act on the magnetic field generation module. Depending on the design of the magnetic field module, various forms of ultrafast magnetic fields can be formed. It can be used in conjunction with a probe station or applied to magneto-optical Kerr microscope systems, etc., which is of great significance for improving electromagnetic testing capabilities and promoting the development of magnetism and spintronics.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a capacitor-based magnetic field device, comprising a high-voltage charging power source module, a capacitor charging and discharging module, and a magnetic field generating module. The high-voltage charging power source module includes a high-voltage DC charging power source for charging the capacitor charging and discharging module. The capacitor charging and discharging module includes at least one capacitor or a group of capacitors, and outputs a voltage pulse to the magnetic field generating module when the capacitor discharges. The magnetic field generating module is excited by the voltage pulse and forms a magnetic field synchronized with the voltage pulse. The magnetic field generating module includes a magnetizing device, which includes at least one of the following units: a single coil unit, a Helmholtz coil unit, a coplanar waveguide unit, and a magnet unit formed by a magnetic core. The capacitor-based magnetic field device further includes an electrical signal monitoring module for monitoring the current of the capacitor charging and discharging module.

[0007] Preferably, the capacitor charging and discharging module includes: a pulse generator and a voltage pulse module. The pulse generator is a device that generates voltage pulse excitation signals, including a waveform generator, and the voltage pulse module is a capacitor-based high-speed pulse generator.

[0008] The pulse generator produces voltage waveform pulses as the trigger excitation signal for the voltage pulse module, controlling the relevant characteristics of the voltage pulse output by the voltage pulse module, including pulse width, frequency, and duration.

[0009] Preferably, the capacitor charging and discharging module includes: a pulse generator, a switching unit, and a capacitor, wherein the switching unit is one or more of the following: a MOSFET, a high-speed relay, or a transistor that performs the switching function.

[0010] The pulse generator generates a trigger signal for the switching unit. When the switching unit is turned on, the capacitor discharges and outputs a voltage pulse. When the switching unit is turned off, the capacitor disconnects and stops discharging.

[0011] Preferably, the capacitor-based magnetic field device further includes: a protection module connected in parallel with the capacitor charging and discharging module for induced voltage surge protection and surge current suppression; the protection module includes at least one of the following units:

[0012] The first protection unit includes: a first diode and a second diode;

[0013] The second protection unit includes: a diode combination circuit, in which four diodes are connected in parallel in pairs and then in series to form a bridge combination;

[0014] The third protection unit includes a varistor.

[0015] Preferably, the electrical signal monitoring module includes at least one of the following units:

[0016] The first electrical signal monitoring unit includes: a signal acquisition device, a sampling resistor, and a joint matching resistor. The sampling resistor and the joint matching resistor are connected in series, and the signal acquisition device is connected in parallel with the sampling resistor. The signal acquisition device is an oscilloscope or a voltage signal acquisition card.

[0017] The second electrical signal monitoring unit includes: an ammeter unit connected in series and a matching resistor. The ammeter unit is a digital multimeter or a multi-function measuring instrument.

[0018] Preferably, the capacitor-based magnetic field device further includes an impedance matching module, wherein different impedance matching resistors are installed on the high-frequency signal line according to different pulse frequencies, and the impedance matching module includes a first impedance matching unit and a second impedance matching unit.

[0019] The first impedance matching unit includes a sampling resistor and a joint matching resistor, which are connected in series and have a total resistance of 50Ω.

[0020] The second impedance matching unit includes a matching resistor with a resistance of 50Ω.

[0021] Preferably, the capacitor-based magnetic field device includes: a current reversing module, which changes the direction of the current passing through the magnetic field generating module, thereby realizing the function of reversing the direction of the generated magnetic field; the current reversing module includes the following implementation: the module includes a first switch and a second switch, the first switch includes a first contact, a second contact and a third contact, the second switch includes a fourth contact, a fifth contact and a sixth contact, the first contact is connected to one end of the capacitor charging and discharging module, the fourth contact is connected to the other end of the capacitor charging and discharging module, the second contact and the sixth contact are connected to one end of the magnetic field generating module, and the third contact and the fifth contact are connected to the other end of the magnetic field generating module.

[0022] A second aspect of the present invention provides a magneto-optical Kerr testing system for measuring the magnetic state of a sample by means of the polarization characteristics of light. The system includes: a light source, a polarization modulator, a polarization detection device for reflected light, an optical path module, a magnetic field generating device, a signal detection and acquisition module, and a control and analysis processing host module. The polarization detection device for reflected light includes: a polarizer, a Wollaston prism, and a photoelectric converter. The magnetic field generating device is based on the magnetic field device described in the first aspect, and the generated magnetic field excites the magnetic thin film and magnetic microstructure sample.

[0023] A third aspect of the present invention provides an integrated electrical and magnetic testing system, comprising a magnetic field probe station, at least one magnetic field generating device, and an electrical testing module, wherein the magnetic field generating device is the magnetic field device according to the first aspect.

[0024] The beneficial effects of this invention are that, compared with existing technologies, it inherits the characteristics of fast capacitor discharge speed and high load capacity while also possessing the good time-domain characteristics of ultra-high-speed MOSFETs and other devices, enabling high-frequency switching. Furthermore, it adds rectification and protection circuits, magnetic field waveform monitoring circuits, and commutation circuits, forming a complete ultra-high magnetic field experimental device. This device can generate nanosecond-level ultra-high voltage electrical excitation signals to act on the magnetic field generation module. Depending on the design of the magnetic field module, various forms of ultrafast magnetic fields can be formed. It can be used in conjunction with a probe station or applied to magneto-optical Kerr microscope systems, etc., which is of great significance for improving electromagnetic testing capabilities and promoting the development of magnetism and spintronics. The excellent time-domain characteristics of this device avoid the problems of limited capacitor energy storage and discharge level fluctuations. The power released within the extremely short discharge time can be kept within the range that the capacitor capacity can bear. Furthermore, the capacitor voltage itself has the characteristic of not abruptly changing, and the voltage peak plateau fluctuation range can meet the accuracy requirements of the experiment. Attached Figure Description

[0025] Figure 1 is a block diagram of a capacitance-based magnetic field device according to the present invention.

[0026] Figure 2 is a schematic diagram of the basic topology circuit of a capacitor-based magnetic field device according to the present invention.

[0027] Figure 3 is a schematic diagram of an extended topology circuit of a capacitor-based magnetic field device according to the present invention.

[0028] In the diagram: 1-High-voltage charging power supply module; 2-Capacitor charging and discharging module; 3-Waveform shaping and protection module; 4-Electrical signal detection and matching module; 5-Current commutation module; 6-Magnetic field generation module; 7-High-voltage DC charging power source; 8-Charging switch; 9-Pulse generator; 10-Field-effect transistor; 11-Capacitor; 12-Adjustable resistor; 13-First diode; 14-Second diode; 15-Signal acquisition device; 16-Sampling resistor; 17-Joint matching resistor; 18-First switch; 19-Second switch; 20-Magnetic generator; 21-Voltage pulse module PVM; 22-Diode combination circuit; 23-Ammeter unit; 24-Matching resistor; 25-Commutator; 26-Magnetic generator. Detailed Implementation

[0029] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The preferred embodiment 1 of the present invention will be further described in detail below with reference to Figures 1 and 2.

[0032] Example 1:

[0033] As shown in Figure 1, a block diagram of a capacitor-based magnetic field device includes a high-voltage charging power supply module 1, a capacitor charging and discharging module 2, a waveform shaping and protection module 3, an electrical signal monitoring and matching module 4, a current commutation module 5, and a magnetic field generating module 6. Among them, the high-voltage charging power supply module 1, the capacitor charging and discharging module 2, and the magnetic field generating module 6 are the basic components, and the remaining modules serve as auxiliary modules to add necessary functional expansion and protection measures to the device.

[0034] As shown in Figure 2, the high-voltage charging power supply module 1 includes a high-voltage DC charging source 7 and a charging switch 8. The positive terminal of the high-voltage DC charging source 7 is connected to one contact of the charging switch 8, and the negative terminal is grounded. The other contact of the charging switch 8 is connected to the positive terminal of the capacitor 11 of the charging and discharging module 2. The voltage of the high-voltage DC charging source 7 is adjustable, preferably but not limited to a maximum output of 1kV high-voltage DC, which charges the capacitor 11 of the capacitor charging and discharging module 2 during output. The charging switch 8 can control the start and stop of charging; charging begins when the switch is closed and stops when the switch is opened after charging is complete.

[0035] The capacitor charging / discharging module 2 includes a pulse generator 9, a field-effect transistor (FET) 10, and a capacitor 11. The output signal terminal of the pulse generator 9 is connected to the gate G of the FET 10, and its negative terminal is grounded. The source S of the FET 10 is connected to the positive terminal of the capacitor 11, and its drain D is connected to the first terminal of the magnetic field generating module 6. The FET 10 can be any type of MOSFET or can be replaced with a high-speed relay or a transistor. The negative terminal of the capacitor 11 is grounded.

[0036] The pulse generator 9 is used as a trigger signal generator. When charging is complete and the discharge cycle begins, the field-effect transistor 10 is initially in the off state, and the circuit is open. When the pulse generator 9 sends a pulse signal with a given amplitude and pulse width, the field-effect transistor 10 is in the conducting state for the duration of the pulse width, that is, the capacitor is in the discharging state during this time, generating an electrical excitation pulse signal with an amplitude equal to the capacitor voltage and a pulse width equal to the pulse signal width sent by the pulse generator 9.

[0037] The aforementioned electrical excitation pulse signal is a high-frequency signal with a pulse width on the order of nanoseconds or microseconds, so the voltage drop change of the capacitor can be kept within a very small tolerance range. If the trigger pulse signal emitted by the pulse generator 9 is a periodic pulse or has a large pulse width, the corresponding generated electrical excitation signal will be consistent in the time domain. However, depending on the different capacitor characteristics, the amplitude of the electrical excitation signal may exhibit corresponding attenuation.

[0038] A waveform shaping and protection module 3 is connected in parallel across the capacitor charging / discharging module 2. The waveform shaping and protection module 3 includes a first resistor 12, a first diode 13, and a second diode 14 connected in series. For example, one end of the adjustable resistor 12 is connected to the drain D of the field-effect transistor 10, and the other end is connected to the negative terminal of the second diode 14. The positive terminal of the second diode 14 is connected to the negative terminal of the first diode 13, and the positive terminal of the first diode 13 is connected to the negative terminal of the capacitor 11 in the capacitor charging / discharging module 2. Those skilled in the art will clearly recognize that the positions of the series-connected first resistor 12, first diode 13, and second diode 14 can be adjusted, including but not limited to connecting the first resistor 12 in series on the positive side of the first diode 13.

[0039] The first diode 13 and the second diode 14 are designed to prevent damage to the device from the reverse voltage surge generated by the inductive load magnetic field generating module 6. Simultaneously with the falling edge of the pulse excitation, the magnetic field generating module 6 generates a reverse electromotive force (EMF) based on the inherent characteristics of the inductive device to prevent instantaneous changes in current. This circuit is in a reverse cutoff state when the capacitor discharges, and in a conducting state after the discharge stops. The current generated by the reverse EMF passes through this module, releasing the energy generated by the reverse EMF.

[0040] Alternatively, this module can be replaced by other combinations of diodes, such as a bridge circuit, or by other forms of protection circuits, such as a varistor.

[0041] The first resistor 12 increases the resistance in the circuit, and its resistance is variable. During the continuous discharge of the capacitor, it can suppress the surge current and absorb the energy released by the reverse electromotive force generated by the magnetic field generation module 6 after the discharge is completed.

[0042] An electrical signal monitoring and matching module 4 is installed between the second terminal of the magnetic field generating module 6 and ground. The electrical signal monitoring and matching module 4 includes a signal acquisition device 15, a second resistor 16, and a third resistor 17. The second resistor 16 and the third resistor 17 are connected in series in the circuit. The other end of the second resistor 16 is connected to the negative terminal of the capacitor 11 of the capacitor charging / discharging module 2, and the other end of the third resistor 17 is connected to the second terminal of the magnetic field generating module 6. The signal acquisition device 15 is connected in parallel across the second resistor 16.

[0043] The electrical signal monitoring and matching module 4 acquires the voltage signal of the second resistor 16 in real time through the signal acquisition device 15. According to I=U / R, the instantaneous current change in the circuit can be obtained, and the magnetic field strength of the magnetic field generation module 6 has a linear relationship with the circuit current, so the corresponding mapping curve can be obtained through calibration and fitting.

[0044] For a single-turn Helmholtz coil, the magnetic field strength at the center follows the Biot-Savart law, i.e.

[0045]

[0046] Therefore, the magnetic field strength at the center of the coil is...

[0047]

[0048] Where μ0 is a constant factor, I is the coil current, and R is the coil radius.

[0049] During the experiment, there may be instances where the test point of the sample is offset from the center of the coil. In such cases, with the center of the coil as (0,0,0), the spatial coordinates can be obtained as follows:

[0050] Relationship between magnetic field and axial distance z along the central axis of the coil

[0051]

[0052] Magnetic field at a point with spatial coordinates (x, 0, z)

[0053]

[0054] Where θ is the angle of rotation relative to the x-axis in the plane of the coil.

[0055] Similarly, the magnetic field generated by a multi-turn coil is

[0056]

[0057] Where N is the number of turns in the coil.

[0058] Alternatively, the signal acquisition device 15 is not limited to an oscilloscope or a voltage signal acquisition card, but can also be a module that performs similar signal acquisition functions.

[0059] The third resistor, 17, is closely connected to the second resistor, 16, and serves as an impedance matching resistor to suppress high-frequency signal reflections. The matching resistors should be tightly connected, typically using 50Ω as the matching impedance. In actual experiments, the impedance can be set according to the signal characteristics and the specific requirements of the experiment; 50Ω is merely a relatively balanced value for various optimal characteristics.

[0060] A current commutation module 5 is provided between the two ends of the capacitor charging / discharging module 2 and the two ends of the magnetic field generating module 6. The current commutation module 5 includes a first switch 19 and a second switch 18. The first switch 19 includes a first contact, a second contact, and a third contact. The second switch 18 includes a fourth contact, a fifth contact, and a sixth contact. The first contact is connected to the drain D of the field-effect transistor 10. The fourth contact is connected to one end of the electrical signal monitoring and matching module 4. The second and sixth contacts are connected to the first end of the magnetic field generating module 6. The third and fifth contacts are connected to the second end of the magnetic field generating module 6.

[0061] When the first contact of the first switch 19 is closed to the second contact, and the fourth and fifth contacts of the second switch 18 are closed, the drain D of the field-effect transistor 10 is connected to the first terminal of the magnetic field generating module 6 and conducts, while one terminal of the electrical signal monitoring and matching module 4 is connected to the second terminal of the magnetic field generating module 6. When the first contact of the first switch 19 is closed to the third contact, and the fourth and sixth contacts of the second switch 18 are closed, the drain D of the field-effect transistor 10 is connected to the second terminal of the magnetic field generating module 6 and conducts, while one terminal of the electrical signal monitoring and matching module 4 is connected to the first terminal of the magnetic field generating module 6. The switching of the contacts of the first switch 19 and the second switch 18 achieves the switching of the direction of the current flowing through the magnetic field generating module 6.

[0062] The first switch 19 and the second switch 18 can be any type of switch, including but not limited to relays. The current reversing module 5 can be switched manually or controlled by sending commands from a host computer to ensure that the contact surface of the contacts is large, the conductivity is good, and the system is stable and reliable; otherwise, various types of noise will be introduced and the service life will be shortened.

[0063] The magnetic field generating module 6 includes at least one magnetizing device 20. As the terminal module of the entire device, the magnetizing device 20 is located at the very end of the entire device. The first end of the magnetic field generating module 6 is connected to the drain D of the field-effect transistor 10, and the second end is connected to the negative terminal of the capacitor 11 of the capacitor charging and discharging module 2.

[0064] The magnetizing device 20 can be a single coil, a parallel double-coil Helmholtz coil, a coplanar waveguide, or other magnetic field generating methods, selected according to the required magnetic field. In the experiment, the pulse width of the voltage excitation single-pulse signal or the duration of the periodic pulse signal must be set according to the resistance of the magnetizing device and the current passing through it. Excessively high power for a short time can easily damage the magnetizing device.

[0065] The magnetic generator 20 can be used in conjunction with equipment such as probe stations and magneto-optical Kerr microscopes to build magnetic field environments for various loads, according to the needs of the experiment.

[0066] Example 2:

[0067] The preferred embodiment 2 of the present invention will be further described below with reference to Figure 3.

[0068] This invention provides a capacitor-based ultrafast magnetic field device with multiple implementations, not limited to a single module combination. It includes, but is not limited to, existing module arrangements and combinations, or the addition or deletion of modules. Figure 3 illustrates another implementation of this invention, which achieves similar functionality.

[0069] As shown in Figure 3, an extended topology circuit diagram of a capacitor-based ultrafast magnetic field device also includes: a high-voltage charging power supply module 1, a capacitor charging and discharging module 2, a waveform shaping and protection module 3, an electrical signal monitoring and matching module 4, a current commutation module 5, and a magnetic field generation module 6.

[0070] The positive and negative terminals of the high voltage DC charging power source 7 of the high voltage charging power source module 1 are connected to the positive and negative terminals of the charging interface of the voltage pulse module PVM21 of the capacitor charging and discharging module 2. The negative terminals of the high voltage DC charging power source 7 and the voltage pulse module PVM21 are grounded at the same time.

[0071] The output port of the pulse generator 9 of the capacitor charging / discharging module 2 is connected to the trigger signal input port of the voltage pulse module PVM21. The negative terminals of both the pulse generator 9 and the voltage pulse module PVM21 are grounded. The positive and negative terminals of the pulse output port of the voltage pulse module PVM21 are connected to the voltage pulse input terminals of the magnetic field generating module 6, respectively.

[0072] In this example, a voltage pulse module (PVM) 21 is used to replace capacitor 11 and MOSFET 10 to achieve the same function. The pulse generator 9 outputs a single pulse signal with a certain pulse width and amplitude, or a periodic pulse signal with a certain frequency, amplitude, and duty cycle, as the trigger signal for the voltage pulse module PVM 21, according to the experimental requirements. The voltage pulse module PVM 21 outputs a voltage excitation signal with the same time-domain characteristics at its output interface, the amplitude of which depends on the charging voltage.

[0073] The pulse generating device 9 includes, but is not limited to, devices and circuit modules capable of generating trigger pulses, such as function waveform generators and arbitrary waveform generators. The amplitude of the generated trigger pulse voltage is set according to the trigger level of the subsequent high-speed switching module or instrument, and must reach the specified trigger level.

[0074] As shown in Figure 3, the diode combination circuit 22 of the waveform shaping and protection module 3 is connected in parallel to the positive and negative output terminals of the pulse output port of the voltage pulse module PVM21 of the capacitor charging and discharging module 2. The diode combination circuit 22 contains four diodes connected in parallel in pairs and then in series.

[0075] The diode combination circuit 22 is a bridge structure built with four diodes. This is a combination of diodes, which reduces the requirements for diode performance and achieves better results through circuit design with the same device performance.

[0076] The ammeter unit 23 and the matching resistor 24 of the electrical signal monitoring and matching module 4 are connected in series in the output circuit. One end of the ammeter unit 23 is connected to the negative terminal of the pulse output terminal of the voltage pulse module PVM21 of the capacitor charging and discharging module 2, and the other end is connected to one end of the matching resistor 24. The other end of the matching resistor 24 is connected to the negative terminal of the circuit commutation module 5.

[0077] The ammeter unit 23 includes, but is not limited to, digital multimeters (DMMs), multi-function measuring instruments, and other devices, enabling real-time monitoring of the current in the circuit. This allows for the calculation of the magnetic field strength generated by the magnetic field generating module 6. The conversion formula requires calibration of the magnetic field generating module 6 to obtain the corresponding current-magnetic field mapping curve.

[0078] The matching resistor 24 is used to suppress high-frequency signal reflection in the circuit. It is generally set to 50Ω as the matching impedance to balance the withstand voltage, power transmission and loss characteristics of high-frequency signal transmission.

[0079] The circuit commutation module 5 is connected in parallel with the magnetic field generating module 6. Its input terminal is connected to the pulse output port of the voltage pulse module PVM21, and its output terminal is connected to the electrical pulse input terminal of the magnetic field generating module 6. The magnetic field generating module 6 is the terminal of the entire device, and its electrical pulse input terminal is connected to the pulse output port of the voltage pulse module PVM21 through the circuit commutation module 5.

[0080] The circuit reversing module 5 can reverse the direction of the current passing through the back-end magnetic field generating module 6, and correspondingly reverse the direction of the magnetic field. This is a very important technique in experiments in electromagnetism, especially in magnetic dynamics.

[0081] The circuit commutation module 5 includes, but is not limited to, the circuit breaker 25, the multi-functional switching module, and various circuit design modules that implement this function.

[0082] The magnetic field generating module 6 has a Helmholtz coil as its magnetic generating device 26, which generates a uniform magnetic field environment in a small area during the experiment.

[0083] The magnetic generating device 26 includes, but is not limited to, various magnetic field generating methods such as single coils, parallel-placed double-coil Helmholtz coils, and coplanar waveguides.

[0084] This invention also provides a magneto-optical Kerr testing system, comprising: an optical path module, a magnetic field generating device, a signal detection and acquisition module, and a control and analysis processing host module. The magneto-optical Kerr testing system uses the magnetic field generating device described in the above specific embodiment, and acquires and processes the magnetization state and magnetic parameters of magnetic thin films or magnetic microstructures through the magneto-optical Kerr effect.

[0085] The present invention also provides an integrated electrical and magnetic testing system, including a magnetic field probe station, at least one magnetic field generating device and an electrical testing module, wherein the magnetic field generating device is based on the magnetic field device described above.

[0086] The beneficial effects of this invention are that, compared with existing technologies, it inherits the characteristics of fast capacitor discharge speed and high load capacity while also possessing the good time-domain characteristics of ultra-high-speed MOSFETs and other devices, enabling high-frequency switching. Furthermore, it adds rectification and protection circuits, magnetic field waveform monitoring circuits, and commutation circuits, forming a complete ultra-high magnetic field experimental device. This device can generate nanosecond-level ultra-high voltage electrical excitation signals to act on the magnetic field generation module. Depending on the design of the magnetic field module, various forms of ultrafast magnetic fields can be formed. It can be used in conjunction with a probe station or applied to magneto-optical Kerr microscope systems, etc., which is of great significance for improving electromagnetic testing capabilities and promoting the development of magnetism and spintronics.

[0087] The applicant of this invention has provided a detailed description of the embodiments of the invention in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the invention. The detailed description is only intended to help readers better understand the spirit of the invention and is not intended to limit the scope of protection of the invention. On the contrary, any improvements or modifications made based on the inventive spirit of the invention should fall within the scope of protection of the invention.

Claims

1. A capacitor-based magnetic field device, comprising a high-voltage charging power supply module, a capacitor charging and discharging module, a protection module, an impedance matching module, a current commutation module, and a magnetic field generating module, characterized in that: The high-voltage charging power module includes: a high-voltage DC charging power source for charging the capacitor charging and discharging module; the capacitor charging and discharging module includes at least one capacitor or a group of capacitors, which outputs voltage pulses to the magnetic field generating module when the capacitor discharges; the magnetic field generating module is excited by the voltage pulses and forms a magnetic field synchronized with the voltage pulses; the magnetic field generating module includes: a magnetizing device, which includes at least one of the following units: a single coil unit, a Helmholtz coil unit, a coplanar waveguide unit, and a magnet unit formed by a magnetic core; the protection module is connected in parallel with the capacitor charging and discharging module for induced voltage surge protection and surge current suppression; the capacitor-based magnetic field device also includes: an electrical signal monitoring module for monitoring the current of the capacitor charging and discharging module; the impedance matching module is used to install different impedance matching resistors on the high-frequency signal line according to different pulse frequencies; the current reversing module is used to change the direction of the current passing through the magnetic field generating module, thereby realizing the function of reversing the direction of the generated magnetic field.

2. The capacitance-based magnetic field device according to claim 1, characterized in that: The capacitor charging and discharging module includes a pulse generator and a voltage pulse module. The pulse generator is a device that generates voltage pulse excitation signals, including a waveform generator. The voltage pulse module is a capacitor-based high-speed pulse generator. The pulse generator generates voltage waveform pulses as trigger excitation signals for the voltage pulse module and controls the relevant characteristics of the voltage pulse output by the voltage pulse module, including pulse width, frequency, and duration.

3. The capacitance-based magnetic field device according to claim 1, characterized in that: The capacitor charging and discharging module includes: a pulse generator, a switching unit, and a capacitor. The switching unit is one or more of the following devices that realize the switching function: MOSFET, high-speed relay, or transistor. The pulse generator generates a trigger signal for the switching unit. When the switching unit is turned on, the capacitor discharges and outputs a voltage pulse. When the switching unit is turned off, the capacitor is disconnected and the discharge stops.

4. The capacitance-based magnetic field device according to any one of claims 1 to 3, characterized in that: The protection module includes at least one of the following units: a first protection unit, including a first diode and a second diode; a second protection unit, including a diode combination circuit, wherein the diode combination circuit contains four diodes connected in parallel in pairs and then in series to form a bridge combination; and a third protection unit, including a varistor.

5. The capacitance-based magnetic field device according to any one of claims 1 to 3, characterized in that: The electrical signal monitoring module includes at least one of the following units: a first electrical signal monitoring unit, including: a signal acquisition device, a sampling resistor and a joint matching resistor, wherein the sampling resistor and the joint matching resistor are connected in series, and the signal acquisition device is connected in parallel with the sampling resistor, wherein the signal acquisition device is an oscilloscope or a voltage signal acquisition card; and a second electrical signal monitoring unit, including: an ammeter unit and a matching resistor connected in series, wherein the ammeter unit is a digital multimeter or a multi-function measuring instrument.

6. The capacitance-based magnetic field device according to any one of claims 1 to 3, characterized in that: The impedance matching module includes a first impedance matching unit and a second impedance matching unit. The first impedance matching unit includes a sampling resistor and a joint matching resistor, which are connected in series and have a total resistance of 50Ω. The second impedance matching unit includes a matching resistor with a resistance of 50Ω.

7. The capacitance-based magnetic field device according to any one of claims 1 to 3, characterized in that: The current reversing module is implemented as follows: the module includes a first switch and a second switch. The first switch includes a first contact, a second contact, and a third contact. The second switch includes a fourth contact, a fifth contact, and a sixth contact. The first contact is connected to one end of the capacitor charging and discharging module, the fourth contact is connected to the other end of the capacitor charging and discharging module, the second and sixth contacts are connected to one end of the magnetic field generating module, and the third and fifth contacts are connected to the other end of the magnetic field generating module.

8. A magneto-optical Kerr testing system for measuring the magnetic state of a sample by means of the polarization characteristics of light, comprising: The system comprises a light source, a polarization modulator, a polarization detection device for reflected light, an optical path module, a magnetic field generating device, a signal detection and acquisition module, and a control and analysis processing host module, wherein the polarization detection device for reflected light includes a polarizer, a Wollaston prism, and a photoelectric converter; characterized in that: the magnetic field generating device is a magnetic field device according to any one of claims 1-7, and the generated magnetic field excites the magnetic thin film and the magnetic microstructure sample.

9. An integrated electrical and magnetic testing system, comprising a magnetic field probe station, at least one magnetic field generating device, and an electrical testing module, characterized in that, The magnetic field generating device is a magnetic field device according to any one of claims 1-7.

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