Method and apparatus for measuring ac magnetic susceptibility, magnetic measurement apparatus, computer readable storage medium

Abstract

The application relates to the technical field of magnetic measurement, and discloses a method for measuring AC magnetic susceptibility, which comprises the following steps: controlling a first excitation coil and a second excitation coil arranged in pairs in an alternating gradient magnetometer to generate a uniform alternating magnetic field in a sample seat region; when frequency conversion testing is performed, the frequency of the uniform alternating magnetic field is adjusted, and a first induction signal of a differential detection coil is acquired; wherein the sample seat is located in a measurement region of the differential detection coil; and the AC magnetic susceptibility of a sample is acquired according to the first induction signal. By multiplexing the device structure of the alternating gradient magnetometer, a uniform alternating magnetic field is generated in the sample seat region as an alternating magnetic field source for measuring the AC magnetic susceptibility of the sample, and the differential detection coil can be integrated into the alternating gradient magnetometer. An alternating magnetic field source and a detection system do not need to be additionally arranged, and the cost of measuring the AC magnetic susceptibility is reduced. The application further discloses a device for measuring AC magnetic susceptibility, a magnetic measurement device and a computer readable storage medium.

Description

Technical Field

[0001] This application relates to the field of magnetic measurement technology, such as a method and apparatus for measuring AC magnetic susceptibility, a magnetic measuring device, and a computer-readable storage medium. Background Technology

[0002] Currently, alternating current magnetic susceptibility (AC susceptibility) refers to the magnetization response characteristics of a material under the influence of an alternating magnetic field. It reflects the material's dynamic response to periodic magnetic fields and is a complex physical quantity. Its real part characterizes the material's ability to store magnetic energy, while its imaginary part characterizes hysteresis loss or energy dissipation. AC susceptibility is measured under different frequencies and temperatures. The frequency dependence of AC susceptibility can reveal magnetic relaxation mechanisms, spin dynamics, and phase transition processes, while the temperature dependence provides crucial data for studying microscopic mechanisms such as magnetic anisotropy and critical phenomena. In the research of superconducting materials, magnetic nanoparticles, and multifunctional magnetoelectric devices, accurate measurement of AC susceptibility is of significant value for theoretical modeling and engineering applications.

[0003] The relevant technology generates a uniform alternating magnetic field through a solenoid, places the sample in the uniform alternating magnetic field, obtains the magnetization response signal of the sample by detecting the voltage induced by the detection coil, and uses a lock-in amplifier to separate it into in-phase and quadrature components, and simultaneously records the AC magnetic susceptibility at different frequencies and temperatures.

[0004] In the process of implementing the embodiments of this disclosure, at least the following problems were found in the related art: The methods for measuring alternating magnetic susceptibility in related technologies usually require the independent configuration of an alternating magnetic field source and detection system. The equipment structure is complex and difficult to integrate with existing magnetic measurement devices, resulting in high measurement costs.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0007] This disclosure provides a method and apparatus for measuring AC magnetic susceptibility, a magnetic measuring device, and a computer-readable storage medium to reduce the cost of measuring AC magnetic susceptibility.

[0008] In some embodiments, the method includes: controlling a pair of first and second excitation coils in an alternating gradient magnetometer to generate a uniform alternating magnetic field in a sample holder region; adjusting the frequency of the uniform alternating magnetic field during frequency conversion testing and acquiring a first induced signal from a differential detection coil; wherein the sample holder is located within the measurement region of the differential detection coil; and acquiring the AC magnetic susceptibility of the sample based on the first induced signal.

[0009] Optionally, adjusting the frequency of the uniform alternating magnetic field and obtaining a first induced signal from the differential detection coil includes: when no sample is installed in the sample holder, performing a frequency adjustment operation on the uniform alternating magnetic field according to a preset frequency range and obtaining a first signal induced by the differential detection coil; when a sample is installed in the sample holder, repeating the frequency adjustment operation to obtain a second signal induced by the differential detection coil; wherein the first induced signal includes a first signal and / or a second signal.

[0010] Optionally, after controlling the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, the method further includes: maintaining the frequency of the uniform alternating magnetic field unchanged during the variable field test, and controlling the bias magnetic field generator in the alternating gradient magnetometer to generate a bias magnetic field in the sample holder region; adjusting the current of the bias magnetic field generator and acquiring the second induced signal of the differential detection coil; and acquiring the AC magnetic susceptibility of the sample based on the second induced signal.

[0011] Optionally, adjusting the current of the bias magnetic field generator and obtaining the second induced signal of the differential detection coil includes: when no sample is installed in the sample holder, performing a current adjustment operation on the bias magnetic field generator according to a preset intensity range to obtain a third signal induced by the differential detection coil; when a sample is installed in the sample holder, repeating the current adjustment operation to obtain a fourth signal induced by the differential detection coil; wherein the second induced signal includes the third signal and / or the fourth signal.

[0012] Optionally, the alternating gradient magnetometer further includes a temperature control device; after controlling the paired first excitation coil and second excitation coil in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, the device further includes: when performing a variable temperature test, maintaining the frequency of the uniform alternating magnetic field unchanged, and controlling the temperature control device to change the temperature of the sample holder region; adjusting the set temperature of the temperature control device, and acquiring the third induction signal of the differential detection coil; and acquiring the AC magnetic susceptibility of the sample based on the third induction signal.

[0013] Optionally, adjusting the set temperature of the temperature regulating device and acquiring the third sensing signal of the differential detection coil includes: when no sample is installed in the sample holder, performing a temperature regulating operation on the temperature regulating device according to a preset temperature range to acquire the fifth signal sensed by the differential detection coil; when a sample is installed in the sample holder, repeating the temperature regulating operation to acquire the sixth signal sensed by the differential detection coil; wherein the third sensing signal includes the fifth signal and / or the sixth signal.

[0014] Optionally, controlling the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region includes: disconnecting the reverse series circuit of the first and second excitation coils and reconnecting them as a series circuit of the same phase, so that the current directions of the first and second excitation coils are consistent; or, reversing the current direction of the first or second excitation coil, so that the current directions of the first and second excitation coils are consistent.

[0015] In some embodiments, the apparatus includes a processor and a memory storing program instructions, wherein the processor is configured to perform the method for measuring alternating current magnetic susceptibility as described above when executing the program instructions.

[0016] In some embodiments, the magnetic measuring device includes: a magnetic measuring device body, comprising a first excitation coil and a second excitation coil arranged in pairs, a bias magnetic field generator, a temperature regulating device, a differential detection coil, and a sample holder; the first excitation coil and the second excitation coil can generate a uniform alternating magnetic field in the sample holder region, the bias magnetic field generator can generate a bias magnetic field in the sample holder region, the temperature regulating device can change the temperature in the sample holder region, the differential detection coil generates an electrical signal at least in response to the change in the uniform alternating magnetic field, and the sample holder is used to mount a sample; and the aforementioned device for measuring alternating magnetic susceptibility is mounted on the magnetic measuring device body.

[0017] In some embodiments, the computer-readable storage medium stores program instructions that, when executed, perform the method described above for measuring alternating current magnetic susceptibility.

[0018] The method and apparatus for measuring AC magnetic susceptibility, the magnetic measuring device, and the computer-readable storage medium provided in the embodiments of this disclosure can achieve the following technical effects: A pair of excitation coils, a first and a second, in an alternating gradient magnetometer generate a uniform alternating magnetic field in the sample holder region, with the sample holder located within the measurement area of ​​a differential detection coil. During frequency conversion testing, the frequency of the uniform alternating magnetic field is adjusted, and the first induced signal from the differential detection coil is acquired. Finally, the AC magnetic susceptibility of the sample is obtained based on the first induced signal. By reusing the device structure of the alternating gradient magnetometer, the first and second excitation coils generate a uniform alternating magnetic field in the sample holder region as the alternating magnetic field source for measuring the AC magnetic susceptibility of the sample. Furthermore, the differential detection coil can be integrated into the alternating gradient magnetometer. This eliminates the need for an additional alternating magnetic field source and detection system, achieving the integration and reuse of existing magnetic measurement devices with devices for measuring AC magnetic susceptibility, thus reducing the cost of measuring AC magnetic susceptibility.

[0019] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of a device for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of another device for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of another device for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 4 This is a schematic diagram of another device for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of another device for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 6 This is a schematic diagram of a method for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 7 This is a schematic diagram of another method for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 8 This is a schematic diagram of another method for measuring AC magnetic susceptibility provided in an embodiment of this disclosure; Figure 9 This is a schematic diagram of an apparatus for measuring alternating current magnetic susceptibility provided in an embodiment of this disclosure.

[0021] Figure label: 10: Sample rod; 11: Sample holder; 12: First flange; 13: Second flange; 14: First detection coil; 15: Second detection coil; 16: Vibration detection device; 17: First excitation coil; 18: Second excitation coil; 19: Fixing structure; 20: First bias magnet; 21: Second bias magnet; 22: Cavity; 23: Heating device; 24: Refrigerant inlet; 800: Device for measuring AC magnetic susceptibility; 801: Processor; 802: Memory; 803: Communication interface; 804: Bus. Detailed Implementation

[0022] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0023] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0024] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0025] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0026] Unless otherwise stated, the term "multiple" means two or more.

[0027] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0028] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0029] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0031] In the embodiments disclosed herein, such as Figure 1 As shown, an alternating gradient magnetometer is disclosed, including a first bias magnet 20, a second bias magnet 21, a first excitation coil 17, a second excitation coil 18, a sample rod 10, and a fixing structure 19. The first bias magnet 20 and the second bias magnet 21 are arranged opposite to each other. The first excitation coil 17 and the second excitation coil 18 are arranged opposite to each other, and the first excitation coil 17 and the second excitation coil 18 can be respectively disposed on the first bias magnet 20 and the second bias magnet 21. One end of the sample rod 10 is provided with a sample holder 11 for mounting the sample, and the other end is provided with a vibration detection device 16 for detecting sample vibration. When the sample is mounted on the sample holder 11, the sample is located between the first excitation coil 17 and the second excitation coil 18, and the sample rod 10 is connected to the fixing structure 19 through the vibration detection device 16.

[0032] Combination Figures 2 to 5As shown, this disclosure provides an apparatus for measuring alternating current magnetic susceptibility, including an alternating gradient magnetometer, a disturbance detection device, and a signal processing device. The alternating gradient magnetometer includes an adjustable magnetic field generator and a sample rod 10; wherein a sample can be placed on the sample rod 10, and the adjustable magnetic field generator can generate a gradient magnetic field or a uniform alternating magnetic field at the sample. The disturbance detection device generates an electrical signal in response to at least a change in the uniform alternating magnetic field. The signal processing device is connected to the disturbance detection device and receives and processes the electrical signal generated by the disturbance detection device.

[0033] In this embodiment of the disclosure, the device for measuring alternating magnetic susceptibility may include all or part of the structure of an alternating gradient magnetometer. The adjustable magnetic field generating device refers to the first excitation coil 17 and the second excitation coil 18 of the alternating gradient magnetometer. The magnetic field directions of the first excitation coil 17 and the second excitation coil 18 can be adjusted manually, mechanically, or by adjusting the current.

[0034] The apparatus for measuring AC magnetic susceptibility provided in this disclosure generates a uniform alternating magnetic field through an adjustable magnetic field generator of an alternating gradient magnetometer. The sample is placed within this alternating gradient magnetic field, and frequency-sweeping operations are performed on the uniform alternating magnetic field to achieve frequency conversion testing of the sample. By changing the frequency of the uniform alternating magnetic field for frequency sweeping, and detecting the electrical signal generated by the magnetic field change due to sample disturbance using a disturbance detection device, the electrical signal generated by the disturbance detection device is processed by a signal processing device to obtain the AC magnetic susceptibility of the sample under uniform alternating magnetic fields at different frequencies. By reusing the equipment structure of the alternating gradient magnetometer and incorporating an adjustable magnetic field generator that can convert the gradient coil into a Helmholtz coil to generate a uniform alternating magnetic field, the apparatus for measuring AC magnetic susceptibility is integrated with existing magnetic measurement devices. This eliminates the need for an additional AC magnetic field source to provide a uniform alternating magnetic field, reducing the equipment modification cost for measuring AC magnetic susceptibility.

[0035] Optionally, the adjustable magnetic field generating device includes a first excitation coil 17 and a second excitation coil 18 arranged in pairs. The first excitation coil 17 and the second excitation coil 18 can be connected in series in phase or in opposite phase; wherein, when connected in phase, a uniform alternating magnetic field is generated at the sample; when connected in opposite phase, a gradient magnetic field is generated at the sample.

[0036] In this embodiment, since the alternating gradient magnetometer needs to apply an alternating gradient magnetic field to the sample to measure its vibration and thus obtain characteristics such as the magnetic moment, the first excitation coil 17 and the second excitation coil 18 are connected in series with opposite directions, meaning the magnetic field directions of the first excitation coil 17 and the second excitation coil 18 are always opposite. To measure the AC magnetic susceptibility of the sample, a uniform alternating magnetic field needs to be applied to the sample. Specifically, the connection method of the first excitation coil 17 and the second excitation coil 18 can be changed manually or mechanically, changing the series connection from reverse (anti-phase series) to a series connection (in-phase series). In this case, the first excitation coil 17 and the second excitation coil 18 form a Helmholtz coil set. Applying an alternating current to the first excitation coil 17 and the second excitation coil 18 will generate a uniform alternating magnetic field between them. The direction of the current in each excitation coil can also be adjusted so that the magnetic field directions of the first excitation coil 17 and the second excitation coil 18 are the same. Then, by periodically and synchronously changing the direction of the current in the first excitation coil 17 and the second excitation coil 18, a uniform alternating magnetic field can be generated between the first excitation coil 17 and the second excitation coil 18.

[0037] Thus, when connected in series in phase, the magnetic fields of the first excitation coil 17 and the second excitation coil 18 are in the same direction, generating a uniform alternating magnetic field at the sample. When connected in series in opposite phases, the magnetic fields of the first excitation coil 17 and the second excitation coil 18 are in opposite directions, generating a gradient magnetic field at the sample. Therefore, without changing the structure of the alternating gradient magnetometer, only the magnetic field directions of the first excitation coil 17 and the second excitation coil 18 need to be adjusted. By multiplexing the alternating gradient magnetometer, the AC magnetic susceptibility of the sample can be measured.

[0038] Optionally, the disturbance detection device includes differential detection coils. The differential detection coils include a first detection coil 14 and a second detection coil 15 arranged in pairs.

[0039] In this embodiment, the first detection coil 14 and the second detection coil 15 are coaxially wound in opposite directions and symmetrically distributed on both sides of the magnetic field area at the lower end of the sample rod 10. The distance between the first detection coil 14 and the second detection coil 15 is the radius of either the first detection coil 14 or the second detection coil 15.

[0040] Thus, when the sample is placed in a uniform alternating magnetic field, the first detection coil 14 and the second detection coil 15 simultaneously sense the sample's magnetic response signal and external environmental noise. Since the environmental noise (such as electromagnetic interference and vibration noise) received by the first detection coil 14 and the second detection coil 15 in symmetrical positions exhibits common-mode characteristics, while the sample's magnetic response signal exhibits differential-mode characteristics due to the consistent magnetic field direction, differential processing can directly suppress common-mode noise while preserving and amplifying the effective signal. Specifically, due to the symmetry and reverse winding characteristics of the differential detection coils, the induced signal generated by external noise in the first detection coil 14 and the second detection coil 15 is a common-mode signal (with the same phase), while the sample's magnetic response signal exhibits a differential-mode signal (with opposite phase) due to the consistent magnetic field direction. By differentially amplifying the output signals of the first detection coil 14 and the second detection coil 15 through the signal processing module, the common-mode noise is canceled out, while the differential-mode signal is effectively extracted, thereby improving the signal-to-noise ratio. Furthermore, the symmetrical distribution of the first detection coil 14 and the second detection coil 15 ensures more uniform detection of the sample's magnetic response, avoiding signal distortion caused by positional deviations of a single detection coil, and further improving the reliability and accuracy of the measurement. No additional complex shielding or filtering devices are required; the existing alternating gradient magnetometer structure can be directly reused to achieve noise suppression, reducing modification costs.

[0041] Optionally, the first detection coil 14 and the second detection coil 15 are symmetrically arranged on both sides of the lower end of the sample rod 10 and distributed along the magnetic field direction of the uniform alternating magnetic field.

[0042] This symmetrical arrangement places the first and second detection coils 14 and 15 in equivalent positions within the magnetic field distribution, uniformly covering the sample's response region in a uniform alternating magnetic field. This ensures a high degree of synchronization between the induction intensity and phase of the sample's magnetization signal by the first and second detection coils 14 and 15. Furthermore, the distribution along the magnetic field direction ensures that the winding axes of the first and second detection coils 14 and 15 are parallel to the magnetic field direction, maximizing the effective induction area of ​​the coils and enhancing the capture efficiency of the sample's magnetic response signal. In addition, the matching design of the magnetic field direction distribution avoids signal attenuation or distortion caused by coil axis misalignment, further guaranteeing the accuracy and repeatability of the measurement results. This structure eliminates the need for complex positioning devices, directly utilizing the compatibility between the magnetic field direction and coil distribution to optimize signal quality, reducing system complexity and debugging costs.

[0043] Optionally, the lower ends of the sample rod 10 extend outward to form a first flange 12 and a second flange 13, and the first detection coil 14 and the second detection coil 15 are respectively wound around the surfaces of the first flange 12 and the second flange 13.

[0044] In this way, the extended flange design provides a fixed physical support and a symmetrically distributed reference surface for the first detection coil 14 and the second detection coil 15, ensuring that the winding positions of the first detection coil 14 and the second detection coil 15 are strictly symmetrical and consistent with the spatial relationship of the magnetic field region where the sample is located, thereby avoiding signal asymmetry or phase shift caused by displacement deviation of the detection coils. Furthermore, the direct winding of the first detection coil 14 and the second detection coil 15 onto the flange surface shortens the physical distance between the coil and the sample, enhancing magnetic field coupling efficiency and enabling the first detection coil 14 and the second detection coil 15 to more efficiently capture the weak magnetic response signal of the sample. In addition, the rigid structure of the flange reduces the influence of external vibration or mechanical deformation on the coil position, ensuring the stability of the coil geometric parameters during measurement and reducing noise introduced by mechanical disturbances. Through the integrated flange and coil layout, there is no need to add complex positioning or fixing devices, simplifying the assembly process and reducing structural complexity while ensuring signal consistency and detection accuracy, achieving low-cost, high-reliability detection system integration.

[0045] Optionally, the sample can be placed inside the first detection coil 14 or the second detection coil 15.

[0046] In this embodiment, a sample cavity for accommodating the sample can be provided within the first flange 12 and / or the second flange 13. When the sample is located within the sample cavity, it is positioned inside the first detection coil 14 or the second detection coil 15. If the cross-section of the first flange 12 and / or the second flange 13 can be an annular, the first detection coil 14 or the second detection coil 15 is wound around the outer surface of the annular wall of the first flange 12 and the second flange 13, respectively, and the sample can be placed within the hollow annular ring. Furthermore, a cover can be used to cover the cross-section of the first flange 12 and the second flange 13 to avoid the influence of air disturbances on the test.

[0047] By placing the sample inside the first detection coil 14 or the second detection coil 15, the sample is directly located in the central region of the magnetic field gradient generated by the first detection coil 14 or the second detection coil 15. This ensures that the magnetic response signal of the sample can be captured by the first detection coil 14 or the second detection coil 15 to the greatest extent, avoiding signal attenuation caused by the sample deviating from the magnetic field sensitive area. Furthermore, since the first detection coil 14 and the second detection coil 15 are symmetrically distributed differential structures, regardless of which detection coil the sample is placed inside, its magnetic field action path in the uniform alternating magnetic field can be guaranteed to be consistent, thereby maintaining the synchronization and symmetry of the induced signals of the first detection coil 14 and the second detection coil 15. In addition, this design allows for flexible selection of the placement position according to the sample shape, size, or experimental requirements. For example, placing the sample on one side can avoid physical interference between the sample and the structure on the other side (such as a temperature control module or fixing device), improving the convenience of experimental operation. By confining the sample to the strongly coupled magnetic field region inside the first detection coil 14 or the second detection coil 15, the extraction efficiency of weak magnetic response signals is enhanced, and there is no need to adjust the structure of the first detection coil 14 or the second detection coil 15 or introduce additional positioning devices. This simplifies the operation process while ensuring the reliability and consistency of the measurement results.

[0048] Optionally, the alternating gradient magnetometer also includes a bias magnetic field generator. The bias magnetic field generator is used to generate a bias magnetic field at the sample.

[0049] In this embodiment of the present disclosure, the bias magnetic field generating device includes a first bias magnet 20 and a second bias magnet 21.

[0050] In this way, by keeping the frequency of the uniform alternating magnetic field constant, the variable magnetic field generator produces a constant uniform alternating magnetic field. Then, by changing the magnetic field strength of the bias magnetic field generated by the bias magnetic field generator, and detecting the electrical signal generated by the magnetic field change due to sample disturbance using a disturbance detection device, the signal generated by the disturbance detection device is processed by a signal processing device to obtain the AC magnetic susceptibility of the sample under different bias magnetic field strengths. By reusing the bias magnetic field generator of the alternating gradient magnetometer, variable field testing of the sample is achieved without the need for an additional bias magnetic field generator, thus reducing testing costs.

[0051] Optionally, the alternating gradient magnetometer also includes a temperature control device for adjusting the temperature of the sample.

[0052] In this embodiment of the disclosure, the adjustable magnetic field generator can be arbitrarily combined with the bias magnetic field generator and the temperature control device according to the testing requirements. For example... Figure 2 As shown, when variable frequency testing is required, the device for measuring AC magnetic susceptibility may consist only of an adjustable magnetic field generator. For example... Figure 3As shown, when variable frequency and variable field tests are required, the device for measuring AC magnetic susceptibility can include an adjustable magnetic field generator and a bias magnetic field generator. For example... Figure 4 As shown, when variable frequency and variable temperature tests are required, the device for measuring AC magnetic susceptibility can include an adjustable magnetic field generator and a temperature control device. For example... Figure 5 As shown, when variable frequency testing, variable field testing, and variable temperature testing are required, the device for measuring AC magnetic susceptibility may also include an adjustable magnetic field generator, a bias magnetic field generator, and a temperature control device.

[0053] In this way, when variable-temperature testing is required, the frequency of the uniform alternating magnetic field remains constant. The temperature of the sample's environment is changed by a temperature control device, and the electrical signal generated by the change in the magnetic field due to sample disturbance is detected by a disturbance detection device. Finally, the electrical signal generated by the disturbance detection device is processed by a signal processing device to obtain the AC magnetic susceptibility of the sample under different temperature environments. By integrating a temperature control device into an alternating gradient magnetometer, variable-temperature testing of the sample is realized without the need for an additional alternating magnetic field source, thus reducing testing costs.

[0054] Optionally, the temperature control device includes a low-temperature chamber. The low-temperature chamber includes a chamber body 22, a heating device 23, and a refrigerant inlet 24; the sample rod 10 extends into the chamber body 22, and when the sample is mounted on the sample rod 10, the sample is located inside the chamber body 22; the refrigerant inlet 24 is located at the bottom of the chamber body 22 for introducing refrigerant into the chamber body 22, and the heating device 23 is used to evaporate the refrigerant to regulate the temperature inside the chamber body 22.

[0055] In this embodiment of the disclosure, a temperature sensor is provided around the sample to detect the temperature of the environment in which the sample is located. The refrigerant flow rate and the power of the heating device 23 can be adjusted by a PID algorithm to keep the ambient temperature of the sample within the target temperature range: when the ambient temperature is less than the minimum value of the target temperature range, the power of the heating device 23 is increased and / or the refrigerant flow rate is decreased to raise the ambient temperature; when the ambient temperature is greater than the maximum value of the target temperature range, the power of the heating device 23 is decreased and / or the refrigerant flow rate is increased to lower the ambient temperature.

[0056] In this embodiment, the cavity wall of the cryogenic chamber adopts a double-layer stainless steel jacket structure. The inner layer can be non-magnetic stainless steel, the outer layer can be a carbon steel frame, and the interlayer between the outer and inner layers can be filled with multiple layers of thermal insulation material. Together with the outer thermal insulation layer, it can effectively isolate external thermal disturbances and reduce internal heat conduction, ensure the temperature uniformity of the sample area, and prevent temperature gradients from interfering with the magnetic response signal.

[0057] Thus, the refrigerant inlet 24 is located at the bottom of the cryogenic chamber. By injecting liquid refrigerant (such as liquid nitrogen or liquid helium) into the chamber 22, the refrigerant evaporates and absorbs heat within the chamber 22, rapidly lowering the ambient temperature of the sample. After the sample rod 10 extends into the chamber 22, the sample is not directly immersed in the liquid refrigerant, but rather in a cryogenic gas environment formed by the refrigerant evaporation. This avoids potential physical interference or signal anomalies caused by direct contact between the liquid refrigerant and the sample. By reusing the original structure of the alternating gradient magnetometer and adding a temperature control device, the synergistic regulation of refrigerant evaporation and heating device 23 covers a wide temperature range for testing, from extremely low temperatures to room temperature.

[0058] In this embodiment of the disclosure, a magnetic measuring device is also disclosed, including: the device for measuring alternating magnetic susceptibility described above; wherein, the alternating gradient magnetometer further includes a vibration detection device 16 connected to a signal processing device, which is at least used to detect the vibration of the sample when the adjustable magnetic field generator generates a gradient magnetic field at the sample.

[0059] Thus, the magnetic measurement device includes a vibration detection device 16 connected to the signal processing device. Through the coordinated detection of vibration signals and magnetic response signals, it achieves multi-functional integration and multi-dimensional analysis of magnetic properties. When the adjustable magnetic field generator switches to gradient magnetic field mode (i.e., the excitation coils are connected in reverse phase), the sample generates mechanical vibration under the action of the gradient magnetic field. The vibration detection device 16 can capture the vibration signal in real time and transmit it to the signal processing device, thereby obtaining the magnetic moment of the sample. This allows for the measurement of both magnetic moment in gradient magnetic field mode and AC magnetic susceptibility in alternating magnetic field mode within the same device, reducing the hardware cost of multi-parameter testing.

[0060] The magnetic measuring device also includes a processor, which is electrically connected to the aforementioned electrical components and is used to control the operation of the aforementioned electrical components.

[0061] Figures 6 to 9 This is a schematic diagram of a method for measuring AC magnetic susceptibility provided in an embodiment of this disclosure. Any of the following methods can be executed in a magnetic measuring device, or in a server or terminal device communicatively connected to the magnetic measuring device. In this embodiment, the solution is described using a magnetic measuring device as the executing entity.

[0062] Based on the structure of the magnetic measuring device described above, such as Figure 6 As shown, this disclosure provides a method for measuring alternating current magnetic susceptibility, comprising: S61, the magnetic measuring device controls the first and second excitation coils, which are arranged in pairs in the alternating gradient magnetometer, to generate a uniform alternating magnetic field in the sample holder area.

[0063] S62, when performing frequency conversion testing, the magnetic measuring device adjusts the frequency of the uniform alternating magnetic field and acquires the first induced signal of the differential detection coil; wherein, the sample holder is located within the measurement area of ​​the differential detection coil.

[0064] S63, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the first induction signal.

[0065] In this embodiment of the disclosure, when the sample is mounted on the sample holder, the sample is always within the sample holder area. When performing frequency conversion testing, only the frequency of the uniform alternating magnetic field is adjusted, while the amplitude of the uniform alternating magnetic field remains constant.

[0066] The method for measuring AC magnetic susceptibility provided in this disclosure involves controlling a pair of first and second excitation coils in an alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, with the sample holder located within the measurement area of ​​a differential detection coil. During frequency conversion testing, the frequency of the uniform alternating magnetic field is adjusted, and a first induced signal from the differential detection coil is acquired. Finally, the AC magnetic susceptibility of the sample is obtained based on the first induced signal. By reusing the device structure of the alternating gradient magnetometer, the first and second excitation coils generate a uniform alternating magnetic field in the sample holder region as the alternating magnetic field source for measuring the AC magnetic susceptibility of the sample. Furthermore, the differential detection coil can be integrated into the alternating gradient magnetometer. This eliminates the need for an additional alternating magnetic field source and detection system, achieving the integration and reuse of existing magnetic measurement devices and devices for measuring AC magnetic susceptibility, thus reducing testing costs.

[0067] Optionally, the magnetic measuring device adjusts the frequency of the uniform alternating magnetic field and acquires a first induced signal from the differential detection coil, including: when no sample is installed in the sample holder, the magnetic measuring device performs a frequency adjustment operation on the uniform alternating magnetic field according to a preset frequency range and acquires a first signal induced by the differential detection coil; when a sample is installed in the sample holder, the magnetic measuring device repeats the frequency adjustment operation and acquires a second signal induced by the differential detection coil; wherein the first induced signal includes a first signal and / or a second signal.

[0068] In this embodiment of the present disclosure, the magnetic measuring device performs frequency adjustment operations including: sequentially changing the frequency of the uniform alternating magnetic field according to a preset frequency range and step size; at each set frequency point, recording the first signal and / or the second signal generated by the change of the uniform alternating magnetic field sensed by the differential detection coil; wherein, the set frequency point is the frequency that the uniform alternating magnetic field can reach by changing the frequency according to the preset step size.

[0069] In this embodiment of the disclosure, the magnetic measuring device acquires the AC magnetic susceptibility of a sample based on a first induction signal, including: the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on a first signal and a second signal; or, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on a second signal. Specifically, when the user selects a fast measurement mode, only the second signal may be acquired; when the user selects a high-precision measurement mode, both the first and second signals are acquired. When the magnetic measuring device measures both the first and second signals, it acquires the AC magnetic susceptibility of the sample based on both signals; when the magnetic measuring device measures only the second signal, it acquires the AC magnetic susceptibility of the sample based on the second signal. The magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the second signal simply by inputting the second signal as a first target signal into the lock-in amplifier; subsequent steps are the same. The magnetic measuring device acquires the AC magnetic susceptibility of the sample based on a first signal and a second signal, including: the magnetic measuring device calculates the difference between the second signal and the first signal to obtain a first target signal, specifically calculated as: Vsample = Vtotal - Vbg, where Vbg is the first signal, Vtotal is the second signal, and Vsample is the first target signal; the first target signal is input into a lock-in amplifier, and phase-sensitive detection is performed using a reference signal (a synchronization signal in phase and frequency with the uniform alternating magnetic field) set by the lock-in amplifier, and the component in phase with the reference signal (Vin-phase) and the orthogonal component (Vquadrature) in the first target signal are separated by a multiplier and a low-pass filter, where the component in phase with the reference signal and the orthogonal component in the first target signal correspond to the real part χ' and the imaginary part χ'' of the AC magnetic susceptibility, respectively; based on the geometric parameters of the differential detection coil and the magnetic field strength of the uniform alternating magnetic field, the real part χ' and the imaginary part χ'' of the AC magnetic susceptibility are calculated, and the specific calculation formula is as follows: H = (8) μ0 N I) / (5√5) a), A=A1 N1; χ'=Vin-phase / (μ0 N ω A H), χ''=Vquadrature / (μ0 N ω A H); Where H is the magnetic field strength of the uniform alternating magnetic field, μ0 is the permeability of free space, N is the number of turns of the first excitation coil or the second excitation coil, I is the driving current, a is the radius of the first excitation coil or the second excitation coil, A is the effective area of ​​the differential detection coil, A1 is the cross-sectional area of ​​a single turn of the differential detection coil, N1 is the total number of turns of the differential detection coil, and ω is the angular frequency of the uniform alternating magnetic field.

[0070] Thus, in the sample-free state, the first signal only contains environmental noise and background interference induced by the differential detection coil itself. In the sample-present state, the second signal is superimposed with the sample's magnetic response signal and background interference. Detecting the first and second signals using the differential detection coil can suppress spatially symmetrical common-mode interference (such as environmental electromagnetic noise and coil thermal noise), but its ability to suppress asymmetric interference (such as response differences caused by coil manufacturing deviations) or time-dependent system noise (such as fluctuations in the alternating magnetic field source and temperature drift) is limited. Furthermore, by acquiring the first and second signals in the sample-free and sample-present states respectively, the signal processing module can use the difference method to eliminate the remaining asymmetric interference and inherent system noise (such as baseline drift introduced by magnetic field source instability), thereby accurately extracting the magnetic response signal generated solely by the sample, i.e., the AC magnetic susceptibility of the sample under the action of a uniform alternating magnetic field at different frequencies. This effectively eliminates system errors introduced by non-sample factors such as alternating magnetic field source fluctuations, environmental electromagnetic interference, and coil temperature drift, significantly improving the signal-to-noise ratio. By combining differential mode signal extraction from the differential probe coil with a dual noise suppression mechanism of background signal subtraction with / without sample, higher-precision signal separation is achieved, ensuring higher accuracy and repeatability in the measurement results of the real and imaginary parts of AC magnetic susceptibility. Furthermore, by performing a full-band frequency sweep within a preset frequency range, a single test can cover the target frequency domain, avoiding timing errors caused by step-by-step testing, and further improving testing efficiency and data consistency.

[0071] Based on the structure of the magnetic measuring device described above, such as Figure 7 As shown, this disclosure provides a method for measuring alternating current magnetic susceptibility, comprising: S61, the magnetic measuring device controls the first and second excitation coils, which are arranged in pairs in the alternating gradient magnetometer, to generate a uniform alternating magnetic field in the sample holder area.

[0072] S62, when performing frequency conversion testing, the magnetic measuring device adjusts the frequency of the uniform alternating magnetic field and acquires the first induced signal of the differential detection coil; wherein, the sample holder is located within the measurement area of ​​the differential detection coil.

[0073] S63, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the first induction signal.

[0074] S71, When performing a variable field test, the magnetic measuring device maintains the frequency of the uniform alternating magnetic field unchanged and controls the bias magnetic field generator in the alternating gradient magnetometer to generate a bias magnetic field in the sample holder area.

[0075] S72, the magnetic measuring device adjusts the current of the bias magnetic field generator and acquires the second induced signal of the differential detection coil.

[0076] S73, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the second induction signal.

[0077] In this embodiment of the disclosure, when performing a variable field test, the frequency and amplitude of the uniform alternating magnetic field are kept constant.

[0078] The method for measuring AC magnetic susceptibility provided in this disclosure maintains a fixed frequency of the uniform alternating magnetic field during variable field testing. Simultaneously, a bias magnetic field generator applies an adjustable DC bias magnetic field to the sample holder region, adjusting its current to change the bias field strength. A second induced signal is then captured by a differential detection coil. Maintaining a constant frequency of the uniform alternating magnetic field eliminates the influence of frequency fluctuations on the dynamic response of the sample's AC magnetic susceptibility, ensuring that the test results only reflect the effect of changes in bias magnetic field strength on the sample. By superimposing a DC bias magnetic field onto a constant uniform alternating magnetic field, the AC magnetic susceptibility of the sample under bias magnetic fields of varying strengths can be measured. By reusing the existing bias magnetic field generator (such as a DC magnet) of the alternating gradient magnetometer, there is no need to add a separate bias field source. This achieves multi-field coupling testing while reducing hardware modification costs and system complexity, and improving equipment integration and testing efficiency.

[0079] Optionally, the magnetic measuring device adjusts the current of the bias magnetic field generator and acquires a second induced signal from the differential detection coil, including: when no sample is installed in the sample holder, the magnetic measuring device performs a current adjustment operation on the bias magnetic field generator according to a preset intensity range to acquire a third signal induced by the differential detection coil; when a sample is installed in the sample holder, the magnetic measuring device repeats the current adjustment operation to acquire a fourth signal induced by the differential detection coil; wherein the second induced signal includes the third signal and / or the fourth signal.

[0080] In this embodiment of the present disclosure, the magnetic measuring device performs current adjustment operation by: sequentially changing the current of the bias magnetic field generator according to a preset intensity range and step size; and recording the third signal and / or fourth signal induced by the differential detection coil at each set intensity point; wherein, the set intensity point is the magnetic field intensity that can be achieved by changing the current of the bias magnetic field generator according to the preset step size.

[0081] In this embodiment of the disclosure, the magnetic measuring device acquires the AC magnetic susceptibility of a sample based on a second induction signal, including: the magnetic measuring device acquiring the AC magnetic susceptibility of the sample based on a third signal and a fourth signal; or, the magnetic measuring device acquiring the AC magnetic susceptibility of the sample based on a fourth signal. Specifically, when the user selects a fast measurement mode, only the fourth signal may be acquired; when the user selects a high-precision measurement mode, both the third and fourth signals are acquired. When the magnetic measuring device measures both the third and fourth signals, it acquires the AC magnetic susceptibility of the sample based on both signals; when the magnetic measuring device measures only the fourth signal, it acquires the AC magnetic susceptibility of the sample based on the fourth signal. For the magnetic measuring device to acquire the AC magnetic susceptibility of the sample based on the fourth signal, it only needs to input the fourth signal as a second target signal into the lock-in amplifier; subsequent steps are the same. The magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the second induced signal, including: the magnetic measuring device calculates the difference between the fourth signal and the third signal to obtain the second target signal, specifically calculated as: Vsample_field=Vtotal_field−Vbg_field, where Vbg_field is the third signal, Vtotal_field is the fourth signal, and Vsample_field is the second target signal; the second target signal is input into a lock-in amplifier, and a synchronization signal with the same frequency and phase as the uniform alternating magnetic field is used as a reference signal for phase-sensitive detection. The in-phase component Vin-phase and the quadrature component Vquadrature are separated by a multiplier and a low-pass filter, where the in-phase component corresponds to the real part χ' of the AC magnetic susceptibility, and the quadrature component corresponds to the imaginary part χ''; based on the geometric parameters of the differential detection coil and the magnetic field strength of the uniform alternating magnetic field, the real part χ' and the imaginary part χ'' of the AC magnetic susceptibility are calculated, as shown in the following formula: χ'=Vin-phase / (μ0 N ω A (H+Hbisa)), χ''=Vquadrature / (μ0 N ω A (H + Hbisa); Where H is the magnetic field strength of the uniform alternating magnetic field, Hbias is the magnetic field strength of the bias magnetic field, μ0 is the permeability of free space, N is the number of turns of the first excitation coil or the second excitation coil, A is the effective area of ​​the differential detection coil, and ω is the angular frequency of the uniform alternating magnetic field.

[0082] Thus, in the sample-free state, the third signal reflects the inherent background of the system, such as fluctuations in the bias magnetic field itself, induced noise from the differential probe coil, and environmental interference. In the sample-containing state, the fourth signal superimposed the magnetic response of the sample under the coupling effect of the uniform alternating magnetic field and the bias magnetic field, along with background interference. By comparing the current adjustment data under sample-free and sample-containing conditions, the signal processing module can accurately subtract common-mode or asymmetric interference components unrelated to the sample, such as bias magnetic field source drift and differential probe coil temperature drift, from the fourth signal based on the baseline characteristics of the third signal. This allows the extraction of the magnetic response signal generated solely by the sample, i.e., the AC magnetic susceptibility of the sample under the superposition of a constant uniform alternating magnetic field and bias magnetic fields of varying intensities. By combining the differential-mode signal extraction from the differential probe coil with the background signal subtraction with / without sample, a dual noise suppression mechanism is achieved, resulting in higher-precision signal separation and ensuring the accuracy of the AC magnetic susceptibility. Simultaneously, full-field scanning within a preset intensity range ensures data coverage of the entire magnetic field range, improving the reliability of the measurement results.

[0083] Based on the structure of the magnetic measuring device described above, such as Figure 8 As shown, this disclosure provides a method for measuring alternating current magnetic susceptibility, comprising: S61, the magnetic measuring device controls the first and second excitation coils, which are arranged in pairs in the alternating gradient magnetometer, to generate a uniform alternating magnetic field in the sample holder area.

[0084] S62, when performing frequency conversion testing, the magnetic measuring device adjusts the frequency of the uniform alternating magnetic field and acquires the first induced signal of the differential detection coil; wherein, the sample holder is located within the measurement area of ​​the differential detection coil.

[0085] S63, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the first induction signal.

[0086] S81, when performing variable temperature testing, the magnetic measuring device maintains a constant frequency of uniform alternating magnetic field and controls the temperature regulating device to change the temperature of the sample holder area.

[0087] S82, the magnetic measuring device adjusts the set temperature of the temperature regulating device and acquires the third induction signal of the differential detection coil.

[0088] S83, the magnetic measuring device obtains the AC magnetic susceptibility of the sample based on the third induction signal.

[0089] In this embodiment of the disclosure, when performing a variable field test, the frequency and amplitude of the uniform alternating magnetic field are kept constant.

[0090] The method for measuring alternating magnetic susceptibility provided in this disclosure maintains a constant frequency of the uniform alternating magnetic field during temperature-varying testing, and adjusts the temperature of the sample holder area using a temperature control device while simultaneously acquiring the third induced signal from the differential detection coil. Maintaining a constant frequency of the uniform alternating magnetic field eliminates interference from frequency variations on the dynamic response of magnetic susceptibility, ensuring that the test results only reflect the influence of temperature changes on the sample's magnetic properties. By adjusting the temperature setpoint, the alternating magnetic susceptibility of the sample under different temperatures can be measured. By integrating the temperature control device and reusing the original alternating magnetic field source of the alternating gradient magnetometer, a full-temperature-range testing function from extremely low temperatures to room temperature is achieved, eliminating the need for an external independent temperature control module and reducing equipment complexity and testing costs.

[0091] Optionally, the magnetic measuring device adjusts the set temperature of the temperature regulating device and acquires a third induction signal from the differential detection coil, including: when no sample is installed in the sample holder, the magnetic measuring device performs a temperature regulation operation on the temperature regulating device according to a preset temperature range and acquires a fifth signal sensed by the differential detection coil; when a sample is installed in the sample holder, the magnetic measuring device repeats the temperature regulation operation and acquires a sixth signal sensed by the differential detection coil; wherein the third induction signal includes the fifth signal and / or the sixth signal.

[0092] In this embodiment of the present disclosure, the magnetic measuring device performs temperature regulation operations by: sequentially changing the opening degree of the electronic expansion valve and / or the power of the heating device according to a preset temperature range and step size; and recording the fifth signal and / or the sixth signal sensed by the differential detection coil at each set temperature point; wherein, the set temperature point is the temperature that the sample holder area can reach by changing the opening degree of the electronic expansion valve and / or the power of the heating device according to a preset step size.

[0093] In this embodiment of the disclosure, the magnetic measuring device acquires the AC magnetic susceptibility of a sample based on a third induction signal, including: the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on a fifth signal and a sixth signal; or, the magnetic measuring device acquires the AC magnetic susceptibility of the sample based on a sixth signal. Specifically, when the user selects a fast measurement mode, only the sixth signal may be acquired; when the user selects a high-precision measurement mode, both the fifth and sixth signals are acquired. When the magnetic measuring device measures both the fifth and sixth signals, it acquires the AC magnetic susceptibility of the sample based on both signals; when the magnetic measuring device measures only the sixth signal, it acquires the AC magnetic susceptibility of the sample based on the sixth signal. The magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the sixth signal simply by inputting the sixth signal as the third target signal into the lock-in amplifier; subsequent steps are the same. The magnetic measuring device acquires the AC magnetic susceptibility of the sample based on the third induced signal, including: the magnetic measuring device calculates the difference between the sixth and fifth signals to obtain the third target signal, specifically calculated as: Vsample_temp = Vtotal_temp − Vbg_temp, where Vbg_temp is the fifth signal, Vtotal_temp is the sixth signal, and Vsample_temp is the third target signal; the third target signal is input into a lock-in amplifier, and a synchronization signal with the same frequency and phase as the uniform alternating magnetic field is used as a reference signal for phase-sensitive detection. The in-phase component Vin-phase and the quadrature component Vquadrature are separated by a multiplier and a low-pass filter, where the in-phase component corresponds to the real part χ' of the AC magnetic susceptibility, and the quadrature component corresponds to the imaginary part χ''; based on the geometric parameters of the differential detection coil and the magnetic field strength of the uniform alternating magnetic field, the real part χ' and the imaginary part χ'' of the AC magnetic susceptibility are calculated, as shown in the following formula: χ'=Vin-phase / (μ0 N ω A H f(T)), χ''=Vquadrature / (μ0 N ω A H f(T)); Where H is the magnetic field strength of the uniform alternating magnetic field, Hbias is the magnetic field strength of the bias magnetic field, μ0 is the permeability of free space, N is the number of turns of the first excitation coil or the second excitation coil, A is the effective area of ​​the differential detection coil, ω is the angular frequency of the uniform alternating magnetic field, and f(T) is the temperature compensation factor (which can be calibrated by the response of a standard sample (such as gadolinium) at different temperatures).

[0094] Thus, in the absence of a sample, the fifth signal records the inherent noise of the system caused by temperature changes (such as thermal deformation of the differential probe coil, magnetic field distortion caused by thermal expansion and contraction of the material, and electromagnetic interference from the temperature control device). In the presence of a sample, the sixth signal superimposes the sample's magnetic response and the aforementioned background interference. By comparing the data from the two temperature control operations, the signal processing module can subtract the temperature-dependent noise component of the fifth signal from the sixth signal (such as baseline shift caused by thermal drift and coil asymmetric response caused by temperature gradients), thereby extracting the magnetization response solely dependent on the sample's temperature—that is, the AC magnetic susceptibility of the sample under a constant uniform alternating magnetic field and different temperatures. By combining the differential-mode signal extraction from the differential probe coil with the background signal subtraction with / without a sample, a dual noise suppression mechanism is achieved, resulting in higher-precision signal separation and ensuring the accuracy of the AC magnetic susceptibility. Simultaneously, the preset temperature range covers key temperature domains such as material magnetic phase transitions and critical phenomena, avoiding measurement blind spots caused by random point selection and ensuring data continuity and integrity.

[0095] Optionally, the magnetic measuring device controls the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, including: the magnetic measuring device disconnects the reverse series circuit of the first and second excitation coils and reconnects them as a series circuit of the same phase, so that the current directions of the first and second excitation coils are consistent; or, the magnetic measuring device reverses the current direction of the first or second excitation coil, so that the current directions of the first and second excitation coils are consistent.

[0096] In this way, by switching the reverse series circuit of the first and second excitation coils to a series circuit of the same phase (direct reconnection), or by reversing the current direction of one coil to make the current directions of the two coils consistent, the coil structure originally used to generate a gradient magnetic field can be converted into a Helmholtz coil configuration. The consistency of the current direction in the series circuit of the same phase ensures that the magnetic fields generated by the first and second excitation coils are superimposed in the sample holder region as a uniform alternating magnetic field (rather than a gradient field), which meets the requirements of AC magnetic susceptibility measurement. By reusing the original coil structure and drive circuit of the alternating gradient magnetometer, there is no need to add an independent Helmholtz coil or other alternating magnetic field source, which significantly reduces the cost and complexity of equipment modification, while maintaining the compatibility of the coil symmetry design and differential detection system, ensuring that the noise suppression capability is not affected by the switching of magnetic field modes. It takes into account the dual requirements of magnetic moment measurement and AC magnetic susceptibility testing, improving the versatility and testing efficiency of the equipment.

[0097] Combination Figure 9As shown, this disclosure provides an apparatus 800 for measuring AC magnetic susceptibility, including a processor 801 and a memory 802. Optionally, the apparatus may further include a communication interface 803 and a bus 804. The processor 801, communication interface 803, and memory 802 can communicate with each other via the bus 804. The communication interface 803 can be used for information transmission. The processor 801 can call logical instructions in the memory 802 to execute the method for measuring AC magnetic susceptibility described in the above embodiment.

[0098] Furthermore, the logic instructions in the aforementioned memory 802 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0099] The memory 802, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 801 executes functional applications and data processing by running the program instructions / modules stored in the memory 802, that is, it implements the method for measuring AC magnetic susceptibility in the above embodiments.

[0100] The memory 802 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 802 may include high-speed random access memory and may also include non-volatile memory.

[0101] Combination Figure 6 As shown, this disclosure provides a magnetic measuring device 900, including a magnetic measuring device body and the aforementioned device 800 for measuring AC magnetic susceptibility. The device 800 for measuring AC magnetic susceptibility is mounted on the magnetic measuring device body. The mounting relationship described herein is not limited to placement within the magnetic measuring device, but also includes mounting connections with other components of the magnetic measuring device, including but not limited to physical connections, electrical connections, or signal transmission connections. Those skilled in the art will understand that the device 800 for measuring AC magnetic susceptibility can be adapted to any feasible magnetic measuring device body, thereby realizing other feasible embodiments.

[0102] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to perform the above-described method for measuring alternating current magnetic susceptibility.

[0103] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and other media capable of storing program code.

[0104] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0106] The methods and products disclosed in the embodiments herein (including but not limited to devices and equipment) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0107] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A method for measuring alternating current magnetic susceptibility, characterized in that, include: The first and second excitation coils, which are arranged in pairs in the alternating gradient magnetometer, are controlled to generate a uniform alternating magnetic field in the sample holder region. When performing frequency conversion testing, the frequency of the uniform alternating magnetic field is adjusted, and the first induced signal of the differential detection coil is obtained; wherein, the sample holder is located within the measurement area of ​​the differential detection coil; The AC magnetic susceptibility of the sample is obtained based on the first induced signal.

2. The method according to claim 1, characterized in that, Adjusting the frequency of the uniform alternating magnetic field and acquiring the first induced signal from the differential detection coil includes: Without a sample installed in the sample holder, the frequency of the uniform alternating magnetic field is adjusted according to a preset frequency range, and the first signal sensed by the differential detection coil is acquired. With the sample mounted on the sample holder, the frequency adjustment operation is repeated to obtain the second signal sensed by the differential detection coil. The first sensing signal includes a first signal and / or a second signal.

3. The method according to claim 1, characterized in that, After controlling the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, the method further includes: When performing variable field tests, the frequency of the uniform alternating magnetic field is kept constant, and the bias magnetic field generator in the alternating gradient magnetometer is controlled to generate a bias magnetic field in the sample holder area. Adjust the current of the bias magnetic field generator and obtain the second induced signal of the differential detection coil; The AC magnetic susceptibility of the sample is obtained based on the second induction signal.

4. The method according to claim 3, characterized in that, Adjusting the current of the bias magnetic field generator and acquiring the second induced signal of the differential detection coil includes: Without a sample installed in the sample holder, the current of the bias magnetic field generator is adjusted according to the preset intensity range to obtain the third signal induced by the differential detection coil. With the sample mounted on the sample holder, repeat the current adjustment operation to obtain the fourth signal sensed by the differential detection coil; The second sensing signal includes a third signal and / or a fourth signal.

5. The method according to claim 1, characterized in that, The alternating gradient magnetometer also includes a temperature control device; after controlling the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region, it also includes: When performing variable temperature testing, the frequency of the uniform alternating magnetic field is kept constant, and the temperature regulation device is controlled to change the temperature of the sample holder area. Adjust the set temperature of the temperature regulating device and obtain the third induction signal of the differential detection coil; The AC magnetic susceptibility of the sample is obtained based on the third induction signal.

6. The method according to claim 5, characterized in that, Adjusting the set temperature of the temperature regulating device and acquiring the third induction signal from the differential detection coil includes: When no sample is installed in the sample holder, the temperature adjustment device is adjusted according to the preset temperature range to obtain the fifth signal sensed by the differential detection coil. With the sample mounted on the sample holder, repeat the temperature adjustment operation to obtain the sixth signal sensed by the differential detection coil; The third sensing signal includes the fifth signal and / or the sixth signal.

7. The method according to any one of claims 1 to 6, characterized in that, Controlling the paired first and second excitation coils in the alternating gradient magnetometer to generate a uniform alternating magnetic field in the sample holder region includes: Disconnect the reverse series circuit of the first and second excitation coils and reconnect them as a series circuit of the same phase, so that the current directions of the first and second excitation coils are the same; or, Reverse the current direction of the first excitation coil or the second excitation coil so that the current direction of the first excitation coil and the second excitation coil are the same.

8. An apparatus for measuring alternating current magnetic susceptibility, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to, when running the program instructions, perform the method for measuring AC magnetic susceptibility as described in any one of claims 1 to 7.

9. A magnetic measuring device, characterized in that, include: The magnetic measurement device body includes a paired first excitation coil and second excitation coil, a bias magnetic field generator, a temperature control device, a differential detection coil, and a sample holder. The first and second excitation coils generate a uniform alternating magnetic field in the sample holder region. The bias magnetic field generator generates a bias magnetic field in the sample holder region. The temperature control device changes the temperature in the sample holder region. The differential detection coil generates an electrical signal in response to changes in the uniform alternating magnetic field. The sample holder is used to mount a sample. The apparatus for measuring alternating current magnetic susceptibility as described in claim 8 is mounted on the main body of the magnetic measuring device.

10. A computer-readable storage medium storing program instructions, characterized in that, When the program instructions are executed, they cause the computer to perform the method for measuring alternating magnetic susceptibility as described in any one of claims 1 to 7.

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