Low temperature vector magnetometry system

Abstract

A low-temperature vector magnetic field ferromagnetic resonance system, comprising: a support (100); a vector magnet unit (200) mounted to the support, an internal vacuum measurement space is formed, and a sample bearing area is arranged in the vacuum measurement space; a refrigerator (300) mounted to the support and configured to provide liquid helium, the liquid helium being stored in a liquid helium pool of the refrigerator; a cold conduction assembly (400) communicating the liquid helium pool of the refrigerator with the sample bearing area to conduct the liquid helium to the sample bearing area; and a sample conveying assembly (500) mounted to the support, having a sample bearing unit (501) and a driving mechanism (502), the sample being borne on the sample bearing unit, and the driving mechanism being configured to drive the sample bearing unit to enter and exit the sample bearing area.

Description

Technical Field

[0001] This invention relates to the field of magnetic material measurement technology, and more specifically to a low-temperature vector magnetic field ferromagnetic resonance system, for example, in a low-temperature environment of 4K to 300K. Background Technology

[0002] The low-temperature vector magnetic field multichannel ferromagnetic resonance system is mainly used to study the spin dynamics properties of advanced magnetic quantum materials. This system involves multiple technical fields, including vacuum technology, microwave measurement technology, and cryogenic refrigeration technology. In materials science research, the low-temperature environment can greatly suppress the interference of thermal disturbances on measurement results, thereby revealing the intrinsic quantum magnetic properties of materials. The vector magnetic field allows the application of magnetic fields in arbitrary directions in three-dimensional space, precisely controlling the orientation and interaction of spins, which is crucial for studying magnetic anisotropy, skyrmions, and other topological magnetic structures. The multichannel design enables simultaneous measurement of the same sample under different conditions, greatly improving data acquisition efficiency, facilitating parameter scanning and comparative experiments, and accelerating material screening and phase diagram plotting.

[0003] However, due to the numerous technical fields involved and the high technical complexity of this system, there is currently no mature device capable of fully realizing cryogenic, vector magnetic field, and multi-channel measurements. Existing measurement systems often struggle to simultaneously perform these multiple functions, mainly facing the following technical difficulties:

[0004] First, realizing a vector magnetic field typically requires multiple magnet configurations (such as multiple pairs of conical magnets), which results in a large external volume of the magnet system and extremely limited internal space. This limited internal space poses significant challenges to the construction of cryogenic environments and the arrangement of multi-channel signal lines.

[0005] Secondly, traditional cryogenic refrigeration methods (such as closed-loop refrigerators with direct conduction cooling) are not only bulky and difficult to fit into the confined space inside a magnet, but the mechanical vibrations they generate during operation are also transmitted to the sample area through rigid connections, severely interfering with high-precision microwave and electrical signal measurements. Achieving a low-vibration cryogenic environment within a confined space is a pressing technical challenge in this field.

[0006] Furthermore, it is extremely difficult to arrange multiple signal transmission lines (including microwave signal lines, electrical signal lines, optical signal paths, etc.) in a small, low-temperature vacuum chamber. Mutual interference can easily occur between the lines, and it is difficult to balance vacuum sealing and signal transmission functions.

[0007] In addition, the sample replacement process in the existing system is cumbersome, usually requiring the entire vacuum chamber to be punctured before the sample is replaced and then the vacuum is re-evacuated and cooled, resulting in low experimental efficiency. Furthermore, the frequent puncture-vacuum cycles have an adverse effect on the chamber's sealing performance and the stability of the low-temperature environment.

[0008] Therefore, there is an urgent need in this field for a measurement system that can simultaneously achieve low vibration and low temperature environment, vector magnetic field loading, multi-channel signal measurement and efficient sample transfer in a confined space. Summary of the Invention

[0009] To address the problem that the limited internal space of vector magnets in existing technologies makes it difficult to achieve compatibility between cryogenic cooling and multi-channel measurement, this application proposes a cryogenic vector magnetic field ferromagnetic resonance system that achieves a low-vibration, low-temperature environment and efficient sample transport within a confined space.

[0010] To achieve the above objectives, the present invention provides a low-temperature vector magnetic field ferromagnetic resonance system, comprising a support, a vector magnet unit, a refrigerator, a cooling conduction component, and a sample transfer component; wherein, the vector magnet unit is mounted on the support, forming a vacuum measurement space within it, and a sample carrying area is provided within the vacuum measurement space; the refrigerator is mounted on the support and configured to provide liquid helium, which is stored in a liquid helium pool of the refrigerator; the cooling conduction component connects the liquid helium pool of the refrigerator to the sample carrying area to conduct liquid helium to the sample carrying area; the sample transfer component is mounted on the support and has a sample carrying unit and a driving mechanism, wherein the sample is carried on the sample carrying unit, and the driving mechanism is configured to drive the sample carrying unit into and out of the sample carrying area.

[0011] The above solution solves the space limitation problem by spatially separating the refrigerator from the sample carrying area and using the cooling conductive component as the cold energy transfer medium. This eliminates the need for the large refrigerator to be placed in the small space inside the vector magnet unit. At the same time, this split layout, combined with the design of the sample transfer component, provides a structural basis for integrating multi-channel measurement interfaces and realizing automated sample transfer within a limited space.

[0012] In one implementation, the vector magnet unit includes multiple pairs of conical magnets configured to generate a multi-directional magnetic field in the sample-bearing region.

[0013] This implementation utilizes the geometric magnetic focusing effect of the conical magnet, which can effectively reduce the overall external size of the magnet while ensuring the uniformity of the magnetic field in the central region. This further frees up the layout margin around the vacuum measurement space, making it easier to install other components and introduce optical and electrical paths.

[0014] As one implementation method, the vacuum measurement space is formed by a multi-channel pipeline structure, with each pipeline converging and connecting at the center. The multi-channel pipeline structure has both vacuum sealing and signal transmission functions.

[0015] This implementation adopts a multi-channel pipeline design, which combines the vacuum chamber and the signal transmission channel into one, avoiding the need for additional welding or assembly of complex flange interfaces in a confined space. This not only ensures the sealing reliability of the ultra-high vacuum environment, but also provides a standardized physical path for the vertical orthogonal introduction of multi-channel signals such as microwave, electrical and optical signals.

[0016] In one implementation, the cooling component enters the vacuum measurement space from one side of the vector magnet unit in a horizontal direction, and the sample transfer component enters the vacuum measurement space from the other side of the vector magnet unit in a horizontal direction, so that the sample carrying unit of the sample transfer component comes into contact with the cooling component.

[0017] This implementation constructs a horizontally opposed spatial orthogonal layout, making full use of the horizontal opening resources on both sides of the vector magnet unit; when the sample carrier unit is pushed into place, it directly docks with the cooling component to form a thermal coupling path. This dynamic docking mechanism avoids the deployment of fixed and vibration-sensitive rigid connectors in the low-temperature zone, and also simplifies the structural complexity inside the low-temperature zone.

[0018] In one implementation, the cooling assembly includes a cold shield, a support cylinder, a cold head, an inlet pipe, and a return pipe; the cold shield has a cylindrical shape; the support cylinder is disposed inside the cold shield; the cold head is disposed inside the support cylinder; the inlet pipe and the return pipe are disposed inside the support cylinder and extend between the liquid helium pool and the cold head.

[0019] This implementation achieves refined thermal management through a multi-layered nested structure. The cylindrical cold shield effectively blocks the intrusion of external room temperature heat radiation into the internal low-temperature zone; the support cylinder provides stable mechanical support and thermal isolation for the cold head and pipelines; the independent arrangement of the inlet and outlet gas pipelines ensures efficient heat exchange of the refrigerant circulation, enabling the cold energy to be stably and continuously delivered to the sample carrying area.

[0020] In one implementation, the cold head includes a first cold head and a second cold head; the first cold head is connected to the intake pipe and the return pipe; the second cold head is spaced apart from the first cold head, and an elastic element is provided between the two.

[0021] This implementation adopts a split cold head design. The first cold head serves as the main heat exchange end, responsible for receiving the cooling capacity of the refrigerant, while the second cold head serves as the output end, connecting with the sample carrying unit. The elastic element in the middle plays a crucial role in mechanical decoupling and flexible heat conduction. This design can effectively absorb and attenuate the micro-vibrations from the refrigerator or fluid pulsation, preventing them from being transmitted to the sample end, thereby ensuring the quiet environment required for high-precision measurement.

[0022] In one implementation, the refrigeration unit is mounted to a bracket via a shock-absorbing assembly.

[0023] This implementation method isolates the refrigeration unit from vibration at the source, cutting off the transmission path of high-frequency vibrations generated by the piston movement of the refrigeration unit compressor to the support and the entire system, thereby further improving the overall stability of the system.

[0024] In one implementation, the damping assembly includes a frame and a mounting plate; the frame is mounted to a support, and the refrigeration unit is located within the frame; the refrigeration unit is mounted to the mounting plate via a damper, so that the refrigeration unit does not contact the frame.

[0025] This implementation method adopts a suspended hoisting structure, which is connected to the outside world only through a damper. This non-rigid contact design eliminates solid sound bridges, and together with the protective function of the frame, it maximizes vibration isolation efficiency while ensuring the safe fixation of the refrigeration unit.

[0026] In one implementation, the damper is a zero-gap nonlinear damper.

[0027] The zero-gap nonlinear damper selected in this embodiment can provide stable damping force over a wide frequency range and has no impact noise or hysteresis effect caused by mechanical gaps. It is particularly suitable for precision measurement systems that are sensitive to micro-vibrations, ensuring the long-term consistency and reliability of vibration isolation performance.

[0028] In one implementation, the drive mechanism includes a motor, a guide rail, and a ball screw mechanism, with the sample carrying unit connected to the ball screw mechanism.

[0029] This implementation method employs a precision transmission scheme that uses a motor-driven ball screw in conjunction with a guide rail, which can convert the rotational motion of the motor into high-precision linear motion of the sample-carrying unit. The high rigidity and low friction characteristics of the ball screw ensure a smooth and stable sample introduction process, while the guide rail restricts the degree of freedom, ensuring that the sample maintains the correct posture and centering accuracy throughout the long-stroke transmission.

[0030] In one implementation, the sample carrying unit includes a retractable bellows, a four-way assembly, a cold shield cylinder, and a coplanar waveguide structure; the retractable bellows is connected to a ball screw mechanism; the four-way assembly is installed to the retractable bellows via a flange; the cold shield cylinder is disposed within the four-way assembly; the coplanar waveguide structure is disposed within the cold shield cylinder, and the sample is mounted on the coplanar waveguide structure.

[0031] This implementation integrates signal transmission and thermal shielding functions within the sample carrier unit; the expandable bellows allows axial expansion and contraction while maintaining a vacuum seal; the four-way assembly serves as a multifunctional carrier, integrating a vacuum interface and internal support; the built-in cold shield provides a localized low-temperature thermal shielding environment for the sample; and the coplanar waveguide structure is directly integrated onto the carrier, enabling in-situ feeding of microwave signals and avoiding the wear and impedance mismatch problems of traditional external cables during movement.

[0032] In one implementation, the system also includes a gate valve configured to switch between an open position and a closed position; in the open position, the gate valve allows the sample carrier unit to enter and leave the vacuum measurement space; in the closed position, the gate valve closes the vacuum measurement space.

[0033] This implementation isolates the main vacuum measurement space from the external or transition chambers via a gate valve. When changing samples, only the local area needs to be evacuated and vacuumed, while the main measurement chamber remains in a high vacuum and low temperature state. This not only significantly shortens the sample change waiting time but also avoids the risk of thermal stress damage and contamination caused by repeated heating and cooling of the main chamber, thus significantly improving experimental throughput and equipment lifespan.

[0034] The low-temperature vector magnetic field ferromagnetic resonance system provided by this invention successfully decouples the vibration of the cooling source from the sample measurement area through a split-type cooling and heat conduction component design, overcoming the limitations of the narrow space of the vector magnet on the low-temperature system. Combined with a six-way pipeline vacuum chamber and an integrated sample carrying unit, it achieves efficient transmission and in-situ measurement of multi-channel signals within a limited space. Furthermore, with a precision-driven sample transfer component and a gate valve isolation mechanism, it enables rapid and non-destructive sample change under low-temperature vacuum conditions. This system significantly improves the experimental efficiency and data quality of magnetic quantum materials research while ensuring extremely low vibration levels and excellent temperature stability. Attached Figure Description

[0035] The above and other features and advantages of exemplary embodiments of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, which are for illustrative purposes only and are not intended to limit the scope of the invention in any way, wherein:

[0036] Figure 1 This is a schematic diagram of the overall structure of the low-temperature vector magnetic field ferromagnetic resonance system according to an embodiment of the present invention.

[0037] Figure 2 This is a schematic cross-sectional view of a low-temperature vector magnetic field ferromagnetic resonance system according to an embodiment of the present invention.

[0038] Figure 3 This is a cross-sectional structural schematic diagram of the vector magnet unit according to an embodiment of the present invention.

[0039] Figure 4 This is a cross-sectional view of the cooling component according to an embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the cold head structure of the cooling component according to an embodiment of the present invention.

[0041] Figure 6 This is a structural schematic diagram of the shock absorption component according to an embodiment of the present invention.

[0042] Figure 7 This is a schematic diagram of the drive mechanism according to an embodiment of the present invention.

[0043] Figure 8 This is a schematic diagram of the sample carrier unit according to an embodiment of the present invention.

[0044] Figure 9 This is a schematic diagram of the gate valve according to an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0046] Compared to the embodiments shown in the accompanying drawings, feasible embodiments within the scope of this disclosure may have fewer components, other components not shown in the drawings, different components, components arranged differently, or components with different connections, etc. Furthermore, two or more components in the drawings may be implemented in a single component, or a single component shown in the drawings may be implemented as multiple separate components.

[0047] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Where the number of components is not specified, the number of components may be one or more; similarly, terms such as “a,” “the,” and “described” do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative orientations when the equipment is in use or as shown in the accompanying drawings; these relative orientations may change accordingly when the absolute position of the described object changes.

[0048] like Figure 1 As shown, this embodiment provides a low-temperature vector magnetic field ferromagnetic resonance system. The system includes a support 100, a vector magnet unit 200, a refrigerator 300, a cooling conduction assembly 400, and a sample transfer assembly 500.

[0049] The support frame 100 serves as the mechanical reference and load-bearing platform for the entire system, supporting and securing other functional components. In specific implementations, the support frame can be a frame structure welded or bolted together from high-strength aluminum alloy or stainless steel profiles, or it can be an integrated optical platform customized to the laboratory space. The support frame not only provides static support but also, through its rigidity and damping characteristics, provides basic vibration isolation and environmental isolation capabilities for the system. It should be understood that the specific form of the support frame is not limited to the frame type shown in the illustration; any support structure capable of providing a stable mounting interface for components such as the vector magnet unit and the refrigerator is applicable to this invention.

[0050] The vector magnet unit 200 is mounted on the support 100, and its interior contains a vacuum measurement space, within which a sample-bearing area is located. Specifically, the vector magnet unit is rigidly fixed to the central region of the support by a flange or a special clamp. Its sealed interior forms a high-vacuum environment, i.e., the vacuum measurement space, which is the core area for conducting low-temperature, high-magnetic-field experiments. The sample-bearing area is located at the geometric center or a region of uniform magnetic field within the vacuum measurement space, serving as the specific physical location for placing the sample to be tested. The design of the vector magnet unit must balance magnetic field generation efficiency with the availability of internal space, ensuring that sufficient operating and measurement windows are reserved for the sample-bearing area while generating the required vector magnetic field. Although in this embodiment the vector magnet unit is described as being mounted at the center of the support, in other embodiments, it can also be offset according to optical path or circuit layout requirements, as long as the sample-bearing area is within the effective magnetic field range.

[0051] The refrigerator 300 is mounted to the support and configured to supply liquid helium, which is stored in a liquid helium pool within the refrigerator. In this embodiment, the refrigerator is typically arranged independently of the vector magnet unit, for example, mounted on a side extension platform of the support, to prevent its mechanical vibrations during operation from directly coupling to the vibration-sensitive magnet or sample area. The liquid helium pool inside the refrigerator serves as a storage container for the cryogenic cold source, maintaining a stable supply of liquid helium through latent heat of phase change or sensible heat exchange. This split layout allows the relatively large and vibrating refrigerator to avoid encroaching on the already limited space inside the vector magnet unit, while also facilitating maintenance and refilling operations. It should be noted that the connection between the refrigerator and the support can be a rigid connection or a flexible connection via subsequent shock-absorbing components; this embodiment only limits the basic positional relationship of its mounting on the support. In particular, the refrigerator is movably mounted to the support, allowing its position on the support to be adjusted relative to the vector magnet unit, facilitating assembly.

[0052] The cooling conductor 400 connects the liquid helium pool of the refrigerator to the sample-bearing area, transferring liquid helium to the sample-bearing area. The cooling conductor forms a heat transfer bridge from the cold source to the load. Specifically, one end of the cooling conductor is inserted into or thermally coupled to the liquid helium pool of the refrigerator, and the other end extends to the sample-bearing area inside the vector magnet unit, forming a continuous heat conduction path. This path can be a fluid loop filled with flowing liquid helium or cold helium gas, a solid conduction link made of highly thermally conductive materials (such as oxygen-free copper or high-purity aluminum), or a combination of both. Through the cooling conductor, the cold energy carried by the liquid helium is efficiently transported to the sample-bearing area, thereby cooling the sample to the target low temperature.

[0053] The sample transfer assembly 500 is mounted on the support 100 and includes a sample carrying unit 501 and a drive mechanism 502. The sample is carried on the sample carrying unit 501, and the drive mechanism is configured to drive the sample carrying unit into and out of the sample carrying area. The sample transfer assembly enables controllable transfer of the sample between a normal temperature atmospheric environment and a low-temperature vacuum measurement environment. The drive mechanism is fixed to the support and provides a precise linear driving force to the sample carrying unit, enabling it to smoothly push into the sample carrying area inside the vector magnet unit along a predetermined trajectory, or to retract it after measurement. The sample carrying unit, as the direct carrier of the sample, not only carries the sample itself but can also integrate measurement accessories such as microwave transmission lines and temperature measuring elements. When the sample carrying unit reaches the sample carrying area, it forms thermal contact with the cooling component, achieving sample cooling. It should be understood that the drive mechanism can be implemented in various ways; in addition to a motor lead screw, pneumatic push rods, hydraulic cylinders, or magnetic coupling transmissions can also be used, as long as the reciprocating motion of the sample carrying unit under vacuum sealing conditions can be achieved. In particular, the sample transfer assembly is movably mounted to the support, which allows the position of the sample transfer assembly on the support to be adjusted relative to the vector magnet unit, facilitating assembly.

[0054] Through the coordinated operation of the above five components, this embodiment constructs a modular low-temperature vector magnetic field ferromagnetic resonance system architecture. The support provides a unified spatial reference; the vector magnet unit defines the core measurement environment; the separate design of the refrigerator and the cold conduction component resolves the contradiction between cold source vibration and confined space; and the sample transfer component endows the system with the ability to dynamically change samples.

[0055] As one implementation method, such as Figure 3 As shown, the vector magnet unit 200 includes multiple pairs of conical magnets ( Figure 3The cross-sectional view shows two pairs of conical magnets (a total of four pairs), configured to generate a multi-directional magnetic field in the sample-bearing region. Specifically, the multiple pairs of conical magnets are arranged along the circumference or a specific axis of symmetry of the sample-bearing region, with each pair of magnets positioned opposite each other and their tips pointing towards the center of the sample-bearing region. This conical geometry utilizes the magnetic focusing effect generated by the gradual change in magnetic pole area, achieving a higher magnetic field strength and gradient uniformity in the sample-bearing region than a cylindrical magnet of the same volume. More importantly, the conical structure allows for a larger root dimension of the magnet to ensure magnetic flux supply, while the dimension near the sample end shrinks significantly, thus naturally enclosing a larger three-dimensional operating space within the magnet array. This space release is crucial for arranging cryogenic components, optical windows, and microwave probes in strong magnetic field environments. Although this embodiment uses conical magnets as an example, in other embodiments, truncated conical, wedge-shaped, or other magnet configurations with variable cross-sections can also be used, as long as they can achieve magnetic field focusing and optimize internal space utilization. Furthermore, the number of "multiple pairs" can be flexibly adjusted according to the dimensionality and uniformity requirements of the target magnetic field. For example, three pairs can be used to achieve a three-dimensional orthogonal vector field, or four or more pairs can be used to improve the continuity and smoothness of the magnetic field rotation. The method by which multiple pairs of conical magnets generate multi-directional magnetic fields is not the focus of this application, as long as multi-directional magnetic fields can be generated.

[0056] As one implementation method, the vacuum measurement space is formed by a multi-channel pipe structure 700, such as... Figure 3 As shown, all pipelines converge and connect at the center, and the multi-port pipeline structure serves both vacuum sealing and signal transmission functions. Specifically, the multiple ports of the multi-port pipeline correspond to different functional channels, such as cooling interfaces, sample transfer interfaces, microwave input / output, electrical measurements, optical windows, and vacuum pumping / monitoring ports. All pipelines seamlessly converge at the geometric center, forming a connected spherical or polyhedral core chamber, which is the vacuum measurement space where the sample-bearing area is located. This integrated design combines the vacuum container wall and the signal transmission channel wall into one, avoiding the cumulative assembly errors and leakage risks of multiple sealing surfaces caused by multiple independent flange connections in traditional designs. At the same time, by eliminating the radial space occupied by external flanges and fasteners, the effective volume utilization rate within the compact space is further improved. It should be understood that "multi-port" can be in the form of four-way, five-way, multi-way, or eight-way, etc., and its core concept is to utilize the integrated pipeline that converges at the center to simultaneously assume the dual roles of vacuum boundary and signal path, rather than being limited to a specific number of ports.

[0057] In one implementation, the cooling component 400 enters the vacuum measurement space horizontally from one side of the vector magnet unit, and the sample transfer component 500 enters the vacuum measurement space horizontally from the other side of the vector magnet unit, so that the sample carrying unit of the sample transfer component contacts the cooling component. Specifically, this horizontally opposed layout makes full use of the structural gap of the vector magnet unit in the horizontal axis. When the sample transfer component drives the sample carrying unit into place along the horizontal axis, its end directly forms a physical docking with the output end of the cooling component located on the opposite side, thereby establishing a stable heat conduction path. This dynamic docking mechanism avoids setting up complex fixed heat exchange interfaces inside the low-temperature vacuum region, which simplifies the internal structure of the cavity and reduces the risk of vibration transmission caused by rigid connections. It should be understood that in this embodiment, "horizontal direction," "one side," and "the other side" are all relative orientation descriptions and are not limitations on absolute geographical coordinates. In other embodiments, if the opening layout of the vector magnet unit or the laboratory space conditions change, the cooling component and the sample transfer component can also enter the vacuum measurement space in a vertically aligned, tilted, or non-collinear manner, as long as they can achieve effective thermal coupling docking within the sample carrying area.

[0058] like Figure 4 and Figure 5 As shown, the cooling assembly 400 includes a cooling screen 401, a support cylinder 402, a cooling head, an inlet pipe 403, and a return pipe 404; the cooling screen has a cylindrical shape and is disposed in one of the aforementioned multi-channel pipes; the support cylinder is disposed inside the cooling screen to support the cooling screen; the cooling head is disposed to the support cylinder; the inlet pipe and the return pipe are disposed inside the support cylinder and extend between the liquid helium pool and the cooling head.

[0059] Specifically, this multi-layered nested structure forms a sophisticated thermal management barrier from room temperature to the ultra-low temperature sample region. The outermost cylindrical cold shield is typically made of high thermal conductivity oxygen-free copper or aluminum alloy, and its surface can be gold-plated or polished to reduce emissivity. Its core function is to intercept and reflect thermal radiation from the room temperature cavity walls, minimizing radiative heat leakage. Compared to square or polygonal cross-sections, the cylindrical shape provides a more uniform stress distribution under atmospheric pressure differences and has the smallest surface area for the same volume, thus reducing the radiative heat absorption area and manufacturing difficulty. The support cylinder located inside the cold shield is typically made of low thermal conductivity materials (such as stainless steel, titanium alloy, or glass fiber reinforced plastic). Its two ends are connected to the cold shield end cap and the internal cold head mounting base, respectively. This provides stable mechanical support for the inlet and outlet air pipes and the cold head, and also acts as a thermal barrier layer to cut off the solid heat conduction path from the cold shield to the internal ultra-low temperature region. The intake and return pipes are arranged parallel or coaxially within the support cylinder, forming an independent refrigerant circulation loop: cryogenic liquid helium or cold helium gas is transported to the cold head for heat exchange through the intake pipe, and the fluid, after absorbing heat and heating up, returns to the refrigerator or is discharged through the return pipe. This dual-pipeline design ensures the continuity of cold energy transfer and heat exchange efficiency. It should be understood that in other embodiments, the cold shield can also be elliptical cylindrical or polygonal prism-shaped, and the support cylinder can be integrally formed with the cold shield and thermal insulation can be achieved through localized thinning, as long as the dual functions of radiation shielding and mechanical support are achieved.

[0060] To further address the issue of vibration from the refrigeration unit being transmitted to the sample end, as one implementation method, the cold head includes a first cold head 405 and a second cold head 406; the first cold head 405 is connected to the inlet pipe and the return pipe; the second cold head 406 is spaced apart from the first cold head, and an elastic element 407 is provided between the two.

[0061] In traditional integrated cold head solutions, the cold head is rigidly connected directly to the refrigeration piping. High-frequency micro-vibrations generated by the piston movement of the compressor and fluid pulsation are transmitted losslessly along the solid path to the sample stage, severely interfering with precision measurement signals such as ferromagnetic resonance. In this embodiment, the first cold head 405 serves as the main heat exchange end, responsible for receiving and concentrating the refrigerant supplied by the inlet pipe; the second cold head 406 serves as the output end, directly connecting to the sample carrier unit to cool the sample. The two are physically separated, with a flexible thermal connection established only through the intermediate elastic element 407. The elastic element 407 plays a dual role: firstly, its elastic deformation capacity absorbs and attenuates axial and radial vibration energy from the first cold head, preventing vibration transmission to the second cold head and the sample; secondly, the elastic element 407 still needs to have sufficient effective thermal conductivity cross-sectional area or be filled with a highly thermally conductive medium to maintain the heat flow path between the first and second cold heads. For example, the elastic element can be a metal bellows, which utilizes the axial flexibility and radial stiffness of thin-walled metal to provide a stable metal heat conduction path while allowing micron-level displacement compensation; it can also be a rubber gasket filled with thermally conductive silicone grease or indium foil, which utilizes the damping properties of polymer materials to dissipate high-frequency vibrations, while reducing contact thermal resistance with the help of interface fillers; it can also be a pre-tightened disc spring assembly or helical spring combined with a flexible copper braided strip, which ensures contact pressure through mechanical pre-tightening and enhances heat conduction through the copper braided strip.

[0062] It should be understood that "elastic component" is a functional generalization of all connecting components that combine elastic buffering and heat conduction. Their specific materials, shapes, and assembly methods can be adapted and selected according to the system's comprehensive requirements for vibration isolation frequency, cooling capacity, and spatial dimensions. Through this split design, the cooling component successfully decouples "cooling capacity acquisition" and "cooling capacity output" mechanically, enabling the sample bearing area to obtain a stable deep cryogenic environment while being free from interference from the mechanical vibration of the cooling source, thus providing the necessary conditions for high-precision quantum magnetic measurements.

[0063] To ensure the low-vibration environment required for precision measurements, this application also constructs a multi-stage vibration isolation system. As one implementation, the refrigerator is mounted to the bracket 100 via a vibration damping component 600. This vibration damping component 600 serves as a mechanical isolation interface between the refrigerator and the system body, aiming to block the transmission path of mechanical vibrations generated by the refrigerator compressor piston movement and fluid pulsation to the bracket and vector magnet unit at the source. By dissipating the refrigerator's vibration energy within an independent vibration damping component, rather than directly coupling it to the high-rigidity bracket, the background noise level of the entire system can be significantly reduced, providing a quiet physical environment for high-sensitivity ferromagnetic resonance signal acquisition.

[0064] Furthermore, as one implementation method, such as Figure 6As shown, the vibration damping assembly 600 includes a frame 601 and a mounting plate 602. The frame 601 is mounted to the bracket 100, and the refrigerator 300 is located inside the frame. The refrigerator 300 is mounted to the mounting plate via a damper 603, ensuring that the refrigerator does not contact the frame. Specifically, the frame constitutes the external protective shell and mounting reference of the vibration isolation system, and its bottom is rigidly fixed to the bracket, providing stable support for the internal suspension structure. The mounting plate 602 serves as the suspension fulcrum for the refrigerator. The refrigerator 300 is suspended below the mounting plate by several dampers, and a safety gap is reserved between the outer wall of the refrigerator and the inner wall of the frame to ensure that the refrigerator will not have any rigid collision or friction with the frame during operation or when subjected to external disturbances. This "floating" non-contact design completely cuts off the solid acoustic bridge between the refrigerator and the bracket, forcing all vibration energy to be transmitted outward through the energy-dissipating element of the damper, thereby maximizing the vibration isolation efficiency. At the same time, the frame provides necessary limiting protection for the refrigeration unit, preventing excessive displacement and swaying under extreme operating conditions.

[0065] Regarding the specific selection of damper 603, as one implementation method, the damper is a zero-gap nonlinear damper. Traditional linear springs or ordinary rubber pads are prone to mechanical gaps or creep relaxation under long-term alternating loads, leading to impact noise or hysteresis effects during high-frequency micro-amplitude vibrations, thus becoming new vibration sources. Zero-gap nonlinear dampers, through pre-tightening mechanisms or special material formulations, maintain constant contact pressure and damping force throughout the entire stroke range, eliminating minute gaps between mating surfaces. Their nonlinear stiffness characteristics enable them to provide adaptive impedance matching for vibrations in different frequency ranges: providing a softer buffer to absorb impact energy in the low-frequency, large-amplitude range, and exhibiting higher dynamic stiffness to suppress resonance amplification in the high-frequency, small-amplitude range. This wide-bandwidth, gapless damping characteristic is particularly crucial for eliminating the high-frequency micro-vibrations unique to refrigeration units, ensuring the stability and consistency of vibration isolation performance throughout the system's entire lifespan. It should be understood that "zero-gap nonlinear damper" is a functional generalization of a class of damping elements with specific mechanical response characteristics. Its specific implementation forms include, but are not limited to, metal wire mesh dampers, preloaded disc spring groups, magnetorheological dampers, or special polymer composite damping pads. Any damping element that meets the requirements of zero mechanical gap and nonlinear stiffness characteristics can be applied to this invention.

[0066] As one implementation method, such as Figure 7As shown, the drive mechanism 502 includes a motor 503, a guide rail 504, and a ball screw mechanism 505, with the sample carrying unit 501 connected to the ball screw mechanism. Specifically, this drive chain constitutes the power basis for the high-precision reciprocating motion of the sample between the ambient temperature atmospheric region and the low-temperature vacuum region. The motor, as the power source, is typically a stepper motor or servo motor to provide precise position control and torque output. The ball screw mechanism converts the rotational motion of the motor into linear motion; its high transmission efficiency and low friction characteristics ensure a smooth and stable sample introduction process, avoiding the crawling phenomenon that may occur with traditional sliding screws. The guide rail is arranged parallel to the screw, restricting the radial degree of freedom of the sample carrying unit, allowing it to move only along a predetermined axis, thereby ensuring attitude stability and alignment accuracy during long-stroke transmission. Regarding vacuum sealing, a magnetohydrodynamic seal or a welded bellows seal assembly is typically installed between the ball screw mechanism and the external atmospheric environment to maintain a high vacuum level in the vacuum measurement space. It should be understood that although this embodiment uses an electric drive scheme with a motor and a ball screw, in other embodiments, alternative schemes such as pneumatic push rods, hydraulic cylinders or magnetic coupling transmissions can be selected according to the degree of automation and load requirements, as long as the controllable linear motion of the sample carrying unit under vacuum sealing conditions can be achieved.

[0067] To achieve a high degree of integration between in-situ microwave signal feeding and thermal shielding, one implementation method is as follows: Figure 7 , Figure 8 and Figure 9 As shown, the sample carrier unit 501 includes a telescopic bellows 506, a four-way assembly 507, a cold shield cylinder 508, and a coplanar waveguide structure 509. The telescopic bellows 506 is connected to a ball screw mechanism; the four-way assembly is mounted to the telescopic bellows via a flange; the cold shield cylinder 508 is disposed within the four-way assembly; the coplanar waveguide structure is disposed within the cold shield cylinder, and the sample is mounted on the coplanar waveguide structure. Specifically, this multi-layered nested integrated design is the core carrier for solving the problem of dynamic measurement in confined spaces. One end of the telescopic bellows 506 is connected to the moving end of the ball screw mechanism, and the other end is connected to the four-way assembly. Its axial telescopic capability allows the sample carrier unit to complete the sample injection stroke while maintaining a vacuum seal, while compensating for dimensional changes caused by installation tolerances and thermal expansion and contraction. The four-way assembly 507, as a multifunctional hub, not only provides an extension interface for the vacuum chamber but also serves as an internal support frame to fix the cold shield cylinder and the coplanar waveguide structure. The 508 cold shielding tube, encased in the coplanar waveguide, effectively blocks direct heating of the sample area by room temperature radiant heat, while also providing an electromagnetic shielding environment for microwave signals. The sample is directly mounted on the signal line of the coplanar waveguide structure, allowing microwave signals to act on the sample in situ without the need for additional adapter cables. This completely avoids the wear, poor contact, and impedance mismatch problems caused by repeated movement of traditional external cables, significantly improving the signal-to-noise ratio and repeatability of high-frequency measurements.

[0068] It is important to emphasize that the "coplanar waveguide" in this embodiment is merely an example of a microwave transmission line suitable for measuring planar magnetic materials and is not intended to limit the invention. In other embodiments, depending on the sample shape and frequency band requirements, this microwave transmission structure can be replaced with other high-frequency transmission line forms such as microstrip lines, striplines, coaxial probes, rectangular waveguides, or substrate-integrated waveguides, as long as it can be integrated within the cold shield and form effective electromagnetic coupling with the sample.

[0069] To ensure the long-term stability of the main measurement chamber environment and improve sample change efficiency, as one implementation method, the system also includes a gate valve 510, configured to switch between an open and closed position. In the open position, the gate valve allows the sample carrier unit to enter and leave the vacuum measurement space; in the closed position, the gate valve closes the vacuum measurement space. Specifically, the gate valve divides the vacuum measurement space into a main chamber and a transition chamber. When a sample needs to be changed, the gate valve is in the closed position, completely isolating the main chamber from the outside. At this time, only the transition chamber needs to be evacuated to remove or load the sample carrier unit, while the main chamber remains under high vacuum and low temperature. After the sample is loaded and the transition chamber is evacuated back to high vacuum, the gate valve switches to the open position, allowing the sample carrier unit to pass through the valve port into the sample carrying area of ​​the main chamber for measurement. This isolation mechanism avoids the need for heating, cooling, and vacuuming cycles throughout the main chamber with each sample change. This not only significantly shortens experimental waiting time and increases equipment throughput, but more importantly, eliminates the risk of thermal stress damage and aging to precision optical components, superconducting magnets, and vacuum seals caused by repeated thermal cycling, thus extending the system's lifespan and maintenance cycle. It should be understood that the gate valve can be pneumatic, electric, or manual, and its sealing method can be selected according to vacuum level requirements, such as metal seals, fluororubber seals, or knife-edge seals, as long as reliable isolation and communication switching between the main chamber and the transition chamber can be achieved.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-temperature vector magnetic field ferromagnetic resonance system, comprising: Bracket (100); A vector magnet unit (200) is installed on the bracket, forming a vacuum measurement space inside. The vacuum measurement space is provided with a sample carrying area. The vector magnet unit includes multiple pairs of conical magnets configured to generate a multi-directional magnetic field in the sample carrying area. A refrigerator (300) is mounted to the bracket and configured to provide liquid helium, the liquid helium being stored in a liquid helium pool of the refrigerator; A cooling component (400) connects the liquid helium pool of the refrigerator to the sample support area to conduct liquid helium to the sample support area; A sample transfer assembly (500), mounted to the support, has a sample carrying unit (501) and a drive mechanism (502), on which the sample is carried, and the drive mechanism is configured to drive the sample carrying unit into and out of the sample carrying area.

2. The system according to claim 1, wherein, The vacuum measurement space is formed by a multi-channel pipeline structure (700), with each pipeline converging and connecting at the center to achieve vacuum sealing and signal transmission.

3. The system according to claim 1, wherein, The cooling component enters the vacuum measurement space from one side of the vector magnet unit in a horizontal direction, and the sample transfer component enters the vacuum measurement space from the other side of the vector magnet unit in a horizontal direction, so that the sample carrying unit of the sample transfer component comes into contact with the cooling component.

4. The system according to claim 1, wherein, The cooling component includes: Cold screen (401) has a cylindrical shape; The support cylinder (402) is installed inside the cold screen; The cold head is set to the support cylinder; The inlet pipe (403) and the return pipe (404) are located inside the support cylinder and extend between the liquid helium pool and the cold head.

5. The system according to claim 4, wherein, The cold head includes: The first cold head (405) is connected to the intake pipe and the return pipe; The second cold head (406) is spaced apart from the first cold head, and an elastic element is provided between the two.

6. The system according to claim 3, wherein, The refrigeration unit is mounted to the bracket via a shock-absorbing assembly (600) to reduce the vibration transmitted from the refrigeration unit to the bracket.

7. The system according to claim 6, wherein, The damping components include: The frame (601) is mounted to the bracket, and the refrigeration unit is located inside the frame; The refrigeration unit is installed on the hoisting plate (602) through the damper (603) so that the refrigeration unit does not come into contact with the frame.

8. The system according to claim 7, wherein, The damper is a zero-gap nonlinear damper.

9. The system according to claim 1, wherein, The drive mechanism (502) includes a motor (503), a guide rail (504), and a ball screw mechanism (505), with the sample carrying unit connected to the ball screw mechanism.

10. The system according to claim 9, wherein, The sample carrier unit includes: A retractable bellows (506) is connected to a ball screw mechanism; The four-way assembly (507) is installed into the expandable bellows via a flange; The cold shield tube (508) is installed inside the four-way assembly; A coplanar waveguide structure (509) is set inside the cold shield cylinder, and the sample is mounted on the coplanar waveguide structure.

11. The system according to claim 10, characterized in that, It also includes a gate valve (510) configured to switch between an open position and a closed position, wherein in the open position the gate valve allows the sample carrier unit to enter and leave the vacuum measurement space, and in the closed position the gate valve closes the vacuum measurement space.

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