In-situ electrical transport and quantum magnetism cooperative characterization system

Abstract

The invention discloses an in-situ electric transport and quantum magnetics collaborative characterization system, and relates to the technical field of material physical property measurement under extreme conditions, the system comprises a multi-physics field coupling module, the multi-physics field coupling module comprises an extreme pressure device, a vector superconducting magnet and a low-temperature constant-temperature device, the extreme pressure device comprises a diamond anvil cell, and the vector superconducting magnet comprises a quantum magnetic field; comprising a nitrogen vacancy color center, an electrical probe and a microstrip transmission line, the cooperative detection module comprises a magnetic detection terminal and an electrical detection terminal and is used for detecting a magnetic signal of the sample to be detected and performing in-situ measurement so as to characterize the electrical transport property; and the position adjustment and vibration isolation module comprises a vibration isolation platform, and the extreme pressure device and the magnetic detection terminal are jointly rigidly fixed on the vibration isolation platform so as to ensure the alignment stability of the micron-sized optical path. According to the invention, the submicron-level optical alignment stability can be realized while accurate loading in a low-temperature, high-intensity magnetic field and high-pressure environment can be ensured, so that the isotactic in-situ electric-magnetic collaborative data with a high signal-to-noise ratio can be obtained.

Description

Technical Field

[0001] This invention relates to the field of material property measurement technology under extreme conditions, and in particular, to an in-situ synergistic characterization system of electrical transport and quantum magnetism. Background Technology

[0002] In condensed matter physics and materials science, the multi-physics coupling environment of low temperature, strong magnetic field, and high pressure is key to discovering novel states of matter. Confirmation of these states of matter relies on dual, synergistic cross-validation of in-situ electrical transport and magnetic response. That is, both sets of data must be obtained under completely identical thermodynamic conditions (same pressure, same temperature, and same magnetic field point).

[0003] Due to the limited functionality of existing experimental setups, current electromagnetic property characterization typically involves separate equipment. Specifically, electrical transport measurements are usually performed in a cryostat integrating high-voltage components, while high-sensitivity magnetic measurements rely on superconducting quantum interference devices (QFIDs) or independent optically probed magnetic resonance (OPM) systems. Researchers must physically transfer the sample between different devices or perform loading measurements at different time periods. This separate measurement approach is not only inefficient but also introduces unavoidable systematic errors due to pressure relaxation during temperature changes or transfers in the high-voltage device, as well as hysteresis and temperature gradient differences under low-temperature, high-magnetic fields. This results in electrical and magnetic data being acquired under non-identical physical conditions, leading to data distortion and making it difficult to establish accurate electromagnetic correspondences.

[0004] In existing technologies, the diameter of the diamond anvil cell facet in a diamond anvil cell is typically only tens to hundreds of micrometers. Within this extremely small area, ensuring high-pressure sealing while simultaneously accommodating electrical leads presents significant space constraints. Furthermore, the introduction of magnetic sensors necessitates the placement of traditional discrete devices, making it impossible to simultaneously acquire electromagnetic signals in the same high-pressure microenvironment. Simultaneously, multi-physics collaborative detection is constrained by the structural contradiction between macroscopic environmental loading and precise microscopic detection. Existing devices, employing rigid connections, allow mechanical vibrations from the low-temperature, high-magnetic-field equipment to be directly transmitted to the high-pressure sample chamber, disrupting sub-micrometer-level optical alignment stability. This vibration-coupled focus drift becomes a key bottleneck restricting the acquisition of high signal-to-noise ratio in-situ collaborative data in complex environments. Summary of the Invention

[0005] The purpose of this invention is to provide an in-situ synergistic characterization system for electrical transport and quantum magnetic properties, which solves the problem of in-situ synergistic characterization of the electrical transport properties and quantum magnetic behavior of materials.

[0006] To achieve the above objectives, this invention provides an in-situ electro-transport and quantum magnetism co-characterization system. This system includes a multi-physics coupling module comprising an extreme pressure device, a vector superconducting magnet, and a cryogenic isothermal device, used to construct a composite physical field environment to meet the requirements for characterizing the magnetoelectric properties of quantum materials under extreme conditions. The extreme pressure device includes a diamond anvil cell, which comprises a nitrogen-vacancy color center injected into the surface layer of a first diamond anvil cell and serving as an embedded magnetic sensor, an electrical probe deposited on the surface of the first diamond anvil cell, and a second diamond anvil cell deposited on the diamond anvil cell. The system includes a microstrip transmission line spanning the sample cavity; a collaborative detection module comprising a magnetic detection terminal and an electrical detection terminal, wherein the magnetic detection terminal is used to detect the magnetic signal of the sample under test using photodetector magnetic resonance, and the electrical detection terminal uses a metal thin-film electrode array to measure the resistance, Hall effect coefficient, and magnetoresistive parameters of the sample under test in situ to characterize its electrical transport properties; and a position adjustment and vibration isolation module comprising a vibration isolation platform, wherein the extreme pressure device and the magnetic detection terminal are rigidly fixed together on the vibration isolation platform, and the extreme pressure device and the magnetic detection terminal remain relatively stationary to ensure micron-level optical path alignment stability.

[0007] The beneficial effects of this invention are as follows:

[0008] This invention provides a system capable of in-situ, coordinated characterization of the electrical transport properties and quantum magnetic behavior of materials under multi-physical field coupling environments such as high pressure, strong magnetic field, and low temperature. It designs an independent magnet support frame and a common-substrate optical-pressure vibration isolation structure, physically separating the vibrating vector superconducting magnet from the precision optical detection components. Through non-contact superposition of physical fields, the transmission of mechanical vibration during the low-temperature strong magnetic field loading process is completely blocked. Specifically, it includes:

[0009] (1) It breaks through the spatial size limitation of extreme pressure devices. By utilizing the atomic size characteristics of nitrogen vacancy (NV) color centers (injected into the diamond lattice) and the micro-nano processing characteristics of metal thin film electrodes, the magnetic sensor is integrated with zero additional volume. This avoids the sensor entity occupying the sample cavity space and ensures the reliability of the electrode contact with the sample under high pressure.

[0010] (2) A system integration and installation design was carried out for multi-physics field and collaborative detection. The system adopts a split architecture design. Considering that the vector superconducting magnet will generate micro-vibrations during operation (especially when liquid helium is refrigerated or the compressor is working), and that magnetic detection based on optical detection magnetic resonance has extremely high requirements for optical path stability (micrometer-level focusing), this invention creatively places the magnet independently on the ground through a support frame, while placing the optical sensitive components and pressure device on a vibration isolation platform. This structure of magnet suspension and optomechanical vibration isolation not only ensures the loading of a strong magnetic field, but also completely eliminates the interference of magnet vibration on precision optical and magnetic measurements;

[0011] (3) Through the functional integration design of diamond anvil cell, the precise matching technology of magnetic field and NV axis, and the vibration isolation scheme of split architecture design on the same platform, high-precision, in-situ, and synchronous characterization of material electrical transport properties and microscopic quantum magnetic signals was achieved in extreme multi-physics coupling environment, providing a powerful experimental tool for revealing the physical mechanism of complex quantum materials.

[0012] (4) It achieves true in-situ synergistic characterization, solving the problem that electrical and magnetic measurements need to be performed separately or on separate devices in traditional techniques. By directly integrating electrodes and magnetic sensors on the diamond anvil, the system can acquire data under completely identical thermodynamic conditions (same time, temperature, pressure, and magnetic field). This is of decisive significance for determining the electro-magnetic property coupling mechanism of materials and studying the critical point of phase transition, eliminating experimental errors caused by environmental differences. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0014] Figure 1 A schematic diagram of the structural relationship of the in-situ electrical transport and quantum magnetic synergistic characterization system provided by the present invention;

[0015] Figure 2 A schematic diagram of a diamond anvil cell for the in-situ electro-magnetic synergistic characterization system provided by this invention;

[0016] Figure 3 for Figure 2 Top view of the diamond anvil cell in the image;

[0017] Figure 4 for Figure 2 Top view of the lower diamond anvil cell;

[0018] Figure 5 Microscopic image of a diamond anvil cell sample cavity;

[0019] Figure 6 This is a fluorescence scan of the NV center in the sample cavity of a diamond anvil cell.

[0020] Figure 7 The ODMR spectrum of the shallow NV color center of the diamond anvil cell facet at 6K 47GPa.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Magnetic detection terminal; 2. Extreme pressure device; 3. Non-magnetic optical platform; 4. Vector superconducting magnet; 5. Low temperature constant temperature device; 6. Triaxial displacement stage; 7. Magnet support frame; 8. Vibration isolation platform; 9. Electrical detection terminal; 10. Upper diamond anvil cell; 11. Microstrip transmission line; 12. Gasket; 13. Metal thin film electrode array; 14. Lower diamond anvil cell; 15. Sample to be tested; 16. Nitrogen vacancy color center. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.

[0024] This invention provides an in-situ synergistic characterization system for electrical transport and quantum magnetism, the system comprising:

[0025] The multiphysics coupling module includes an extreme pressure device 2, a vector superconducting magnet 4, and a cryogenic isothermal device 5, which are used to construct a composite physical field environment to meet the requirements of characterizing the magnetoelectric properties of quantum materials under extreme conditions. The extreme pressure device 2 includes a diamond anvil cell, which includes a nitrogen vacancy center 16 injected into the surface of the first diamond anvil cell and used as an embedded magnetic sensor, an electrical probe laid on the surface of the first diamond anvil cell, and a microstrip transmission line 11 laid on the second diamond anvil cell and spanning the sample cavity.

[0026] The collaborative detection module includes a magnetic detection terminal 1 and an electrical detection terminal 9. The magnetic detection terminal 1 is used to detect the magnetic signal of the sample 15 under test using photodetector magnetic resonance. The electrical detection terminal 9 uses a metal thin film electrode array 13 to measure the resistance, Hall effect coefficient and magnetoresistive parameters of the sample 15 under test in situ to characterize its electrical transport properties.

[0027] The position adjustment and vibration isolation module includes a vibration isolation platform 8, an extreme pressure device 2 and a magnetic detection terminal 1, which are rigidly fixed on the vibration isolation platform 8. The extreme pressure device 2 and the magnetic detection terminal 1 remain relatively stationary to ensure micron-level optical path alignment stability.

[0028] In the diamond anvil cell: nitrogen-vacancy color centers 16 are formed inside the surface layer of the first diamond anvil cell by ion implantation, serving as an embedded magnetic sensor and not occupying the surface space of the diamond anvil cell; the electrical probe is a metal thin film electrode array 13, which is directly deposited or micromanipulated and transferred to the surface of the first diamond anvil cell that has been implanted with nitrogen-vacancy color centers 16 through micro-nano fabrication technology; the microstrip transmission line 11 is used for microwave manipulation of the nitrogen-vacancy color centers 16, which is transferred and laid to the second diamond anvil cell through micro-nano fabrication technology or micromanipulation and spans the sample cavity.

[0029] The extreme pressure device 2 includes a spatially integrated diamond anvil cell and an in-situ air film pressurization unit. The diamond anvil cell is installed on the pressurization base of the in-situ air film pressurization unit via a diamond anvil cell press. The in-situ air film pressurization unit is used for in-situ continuous pressure regulation in low temperature and strong magnetic field environments. The in-situ air film pressurization unit includes an air source, a pneumatic pressure controller, a high-pressure air circuit, a pressurization base, and an air film sheet. The air film sheet is located between the pressurization base and the non-diamond anvil face of the diamond anvil cell. The internal cavity of the air film sheet is connected to the pneumatic pressure controller and the air source through the high-pressure air circuit. The low temperature is a temperature below a predetermined temperature threshold, and the strong magnetic field is a magnetic field strength above a predetermined magnetic field strength threshold.

[0030] The position adjustment and vibration isolation module also includes a three-axis displacement stage 6 and a non-magnetic optical platform 3, which are used to adjust the relative position of the sample to be tested 15 and the magnetic detection terminal 1. The extreme pressure device 2 is installed on the three-axis displacement stage 6 and is installed to the vibration isolation platform 8 through the three-axis displacement stage 6. The magnetic detection terminal 1 is installed on the non-magnetic optical platform 3 and is installed to the vibration isolation platform 8 through the non-magnetic optical platform 3.

[0031] In the multiphysics coupling module: a vector superconducting magnet 4 is independently installed on an external magnet support frame 7, physically separated from the magnetic detection terminal 1 to block the transmission of vibrations generated during magnet operation, and is used to generate a magnetic field of predetermined magnitude and direction at the sample chamber of the extreme pressure device 2; a cryogenic isothermal device 5 is installed on a triaxial displacement stage 6 to maintain a constant temperature of the sample 15 to be tested in the sample chamber of the extreme pressure module; wherein, the extreme pressure device 2 is vertically installed and fixed on the cold head inside the cold chamber of the cryogenic isothermal device 5, the central axis of the vector superconducting magnet 4 is coaxially arranged with the central axis of the sample chamber of the extreme pressure device 2, and an isolation gap is reserved between the vector superconducting magnet 4 and the cryogenic isothermal device 5 to prevent the operating vibration of the vector superconducting magnet 4 from being transmitted to the extreme pressure device 2 through the cryogenic isothermal device 5, wherein the isolation gap can be 10mm-20mm.

[0032] In the collaborative detection module, the magnetic detection terminal 1 uses photodetector magnetic resonance (PDMR) via a 532nm laser source, a microwave source, and a fluorescence detector. This includes: a 532nm laser source, a microwave source, and a fluorescence detector arranged coaxially on a non-magnetic optical platform 3; the pump light output from the 532nm laser source is modulated by a polarizer and a waveplate and then focused onto the sample cavity to initialize the spin polarization of nitrogen-vacancy color centers 16; the microwave source introduces microwave pulses into the sample cavity of the extreme pressure device 2 via an RF coaxial line, driving the spins to resonantly transition; the fluorescence detector collects the fluorescence signal radiated during the spin relaxation of nitrogen-vacancy color centers 16, converts it into an electrical signal via a photomultiplier tube, and inputs it into the data acquisition system; the 532nm laser source, microwave source, and fluorescence detector are triggered and synchronized by a timing synchronization controller to jointly complete the signal excitation and detection of photodetector magnetic resonance; the triaxial displacement stage 6 and the magnetic detection terminal 1 are fixed together on the vibration isolation platform 8.

[0033] In the collaborative detection module, the electrical detection terminal 9 uses a metal thin film electrode array 13 connected to the sample 15 to be tested for in-situ measurement of resistance, Hall effect and magnetoresistive parameters. Specifically, the electrical detection terminal 9 adopts a four-wire layout, and the metal thin film electrode array 13, which is fabricated by micro-nano processing, makes ohmic contact with the surface of the sample 15. An excitation current is applied using a current source, and the voltage response of the sample 15 is synchronously acquired by a voltmeter to perform in-situ measurement of resistance, Hall effect and magnetoresistive parameters in a temperature range of 2.6K-300K and a magnetic field range of 0-1T.

[0034] The spatial position of the extreme pressure device 2 is adjusted by the three-axis displacement stage 6 so that the sample cavity inside the extreme pressure device 2 is located at the laser focus of the magnetic detection terminal 1 and at the center of the uniform magnetic field generated by the vector superconducting magnet 4, so that the central field of the suspended vector superconducting magnet 4, the optical path focus of the magnetic detection terminal 1 and the sample cavity coincide in space.

[0035] The vector superconducting magnet 4 consists of three sets of superconducting coils used to generate a magnetic field. The direction of the generated magnetic field is determined to be parallel to the axis of the nitrogen vacancy center 16 in the first diamond anvil face by monitoring the maximum fluorescence intensity of the nitrogen vacancy center 16 under microwave-free conditions.

[0036] The in-situ pressurization process of the in-situ gas film pressurization unit is as follows: there is a sealed cavity inside the gas film, and the sealed cavity is connected to the pneumatic pressure controller and the gas source through a high-pressure gas path. The pneumatic pressure control is used to regulate the output of high-pressure gas from the gas source. The high-pressure gas is injected into the cavity of the gas film through the high-pressure gas path so that the gas film expands uniformly to pressurize the sample chamber in situ.

[0037] The following section further elaborates on the multiphysics coupling module, the collaborative detection module, the position adjustment and vibration isolation module in this invention.

[0038] For multiphysics coupling modules:

[0039] The extreme pressure device 2 is based on diamond anvil cell technology and integrates the functions of the diamond anvil cell. It integrates an in-situ gas film pressurization unit, which can realize in-situ and continuous pressure regulation.

[0040] Nitrogen-vacancy (NV) color centers 16 are injected into the surface of the first diamond anvil cell to serve as an embedded quantum magnetic sensor. At the same time, a metal thin film electrode array 13 is deposited on the first diamond anvil cell using micro-nano fabrication technology or micro-manipulation transfer. The sample to be tested 15 is placed in the sample cavity between the two diamond anvil cells and is in direct and close contact with the metal thin film electrode array 13. Here, the two diamond anvil cells include the first diamond anvil cell and the second diamond anvil cell of the diamond anvil cell.

[0041] The second diamond anvil facet is also laid with a microstrip transmission line 11 across the sample cavity through micro-nano processing technology or micro-manipulation transfer to ensure that the microwave signal can directly act on the NV color center 16.

[0042] The in-situ air film pressurization unit consists of an air source, a pneumatic pressure controller, a high-pressure air circuit, a pressurization base, and an air film sheet with a cavity. The air film sheet is located between the pressurization base and the non-diamond anvil side of the diamond anvil. The air film sheet has a sealed cavity inside, and this cavity is connected to the pneumatic pressure controller and the air source through the high-pressure air circuit.

[0043] The in-situ pressurization process of the in-situ gas film pressurization unit is as follows: the high-pressure gas output from the gas source is precisely controlled by the pneumatic pressure controller. The high-pressure gas is injected into the cavity of the gas film through the high-pressure gas path, so that the gas film expands uniformly, thereby applying a stable driving force to the diamond anvil and realizing in-situ pressurization of the sample chamber. This pressurization method does not require disassembling the sample to be tested 15 and can achieve continuous adjustment from atmospheric pressure to the target high pressure in multi-physical field coupling environments such as low temperature and strong magnetic field.

[0044] The vector superconducting magnet 4 consists of three sets of superconducting coils that can be independently or in combination energized to generate a magnetic field of adjustable magnitude (0-1T) and direction at the sample chamber of the extreme pressure device 2. The direction of the generated magnetic field is modulated to be parallel to the axis of the NV color center 16 in the first diamond anvil face of the diamond anvil.

[0045] The low-temperature constant temperature device 5 adopts a liquid helium closed-loop refrigeration system, which can stabilize the temperature of the area where the sample 15 is located within the adjustable range of 2.6K-300K.

[0046] The components of the multiphysics coupling module work together to precisely construct a composite physical field environment of "low temperature-directional strong magnetism-high pressure" to meet the requirements for characterizing the magnetoelectric properties of quantum materials under extreme conditions.

[0047] For the collaborative detection module:

[0048] The magnetic detection terminal 1 uses the optically detected magnetic resonance (ODMR) method. By exciting the NV color center 16, applying microwave scanning and detecting the change in fluorescence intensity, the ODMR spectrum is obtained, and then the microscopic magnetic parameters of the sample 15 to be tested are analyzed.

[0049] Optical Probe Magnetic Resonance (ODMR) achieves high-sensitivity magnetometry based on the spin level characteristics of NV center 16: A specific wavelength 532 nm laser is emitted to continuously excite NV center 16 to an excited state; a tunable frequency microwave pulse is applied through a microstrip transmission line 11 on a second diamond anvil face to modulate the spin state of NV center 16; and the fluorescence intensity change of NV center 16 (fluorescence wavelength approximately 637 nm) is acquired using a high-sensitivity fluorescence detector. When the microwave frequency is consistent with the wavelength of NV center 16, the fluorescence intensity is measured. s =0 and m s When the energy level splitting distance is matched to ±1, spin resonance transitions are induced, resulting in a significant decrease in fluorescence intensity. ODMR resonance lines are obtained by scanning microwave frequencies. Based on the resonance frequency shift of the spectral lines and the linear relationship between energy level splitting and magnetic field strength, the magnetic parameters of the sample 15, such as quantum magnetic moment, local magnetic field distribution, and magnetic susceptibility, are analyzed.

[0050] The electrical detection terminal 9 is connected to the sample 15 to be tested via the metal thin film electrode array 13, enabling in-situ measurement of electrical transport parameters such as resistance, resistivity, and Hall effect.

[0051] For the position adjustment and vibration isolation module:

[0052] The three-axis displacement stage 6 is used to precisely adjust the relative position of the sample to be tested 15 and the magnetic detection terminal 1;

[0053] The extreme pressure device 2 and the magnetic detection terminal 1 are installed together on the vibration isolation platform 8 to achieve "synchronous vibration isolation on the same platform", which effectively suppresses external vibration interference and ensures the stability of signal acquisition. The vector superconducting magnet 4 is installed on the magnet support frame 7, which is an independent structure from the vibration isolation platform 8 and the device installed on it, and does not interfere with each other.

[0054] This invention constructs a collaborative characterization system based on microscopic vertical integration and macroscopic mechanical decoupling. For microscopically confined spaces, such as... Figure 2 , Figure 3 , Figure 4 As shown, Figure 2 This is a schematic diagram of a diamond anvil cell for the in-situ electrical transport and quantum magnetic synergistic characterization system provided by the present invention. Figure 3 for Figure 2 Top view of the upper diamond anvil cell 10. Figure 4 for Figure 2 The top view of the lower diamond anvil cell 14 in the figure shows a vertical integration strategy employing NV color centers within the crystal lattice, surface thin-film electrodes, and opposing microwave lines. Utilizing ion implantation and micro / nano fabrication techniques, the coexistence and non-interference of the magnetic sensor, electrical probe, and microwave components within a micrometer-level high-pressure cavity are achieved with zero additional volume, ensuring in-situ acquisition of electromagnetic signals within the same micro-region. For collaborative measurement in the macroscopic environment, a decoupled architecture of independent magnet suspension and photo-pressure co-substrate vibration isolation is constructed. This mechanically separates the vibrating magnet from the precision detection components. Using non-contact superposition technology of physical fields, sub-micrometer-level optical alignment and high signal-to-noise ratio synchronous signal acquisition are achieved under low-temperature, high-magnetic-field conditions while completely blocking vibration transmission.

[0055] The implementation process of the in-situ electro-transport and quantum magnetic synergistic characterization system provided by the present invention will be described in detail below.

[0056] Step 1: The diamond anvil cell is integrated into the design and loaded onto the sample to be tested, 15.

[0057] An NV color center 16 for magnetic measurement is embedded into the first diamond anvil facet of a diamond anvil cell using micro-nano fabrication technology, serving as an embedded quantum magnetic sensor. A metal thin-film electrode array 13 for electrical measurement is then fabricated using micro-nano fabrication technology. A microstrip transmission line 11 for manipulating microwave near-field radiation for quantum sensing is laid on the second diamond anvil facet of the diamond anvil cell, spanning the sample cavity region. The sample to be tested 15 is placed in the center of the sample cavity between the two diamond anvil facests, ensuring a tight and stable electrical contact between the sample to be tested 15 and the first diamond anvil facet of the laid metal thin-film electrode array 13. Simultaneously, the microstrip transmission line 11 on the second diamond anvil facet is ensured to span the sample cavity and cover the active area of ​​the NV color center 16. A pressure-transmitting medium (such as an inert gas or solid medium) is filled into the sample cavity to ensure uniform pressure transmission. The two diamond anvil faces are lightly pre-compressed using the pressure screws of a diamond anvil cell press, completing the initial encapsulation. Check the air path sealing of the in-situ air film pressurization unit to ensure there are no leaks at the connection between the air source and the air film. Simultaneously check the continuity and integrity of the signal connections between the metal thin-film electrode array 13 and the electrical detection terminal 9, and between the microstrip transmission line 11 and the magnetic detection terminal 1. The specific process is described below:

[0058] A diamond anvil cell with the

[111] crystal orientation and a diamond anvil cell diameter of 150 μm was used. Figure 2 The surface of the anvil (i.e. the first diamond anvil) of the lower diamond anvil 14 is formed with NV color centers 16 with a depth of about 5-50 nm by ion implantation.

[0059] The metal thin film electrode array 13 is made of molybdenum material and is prepared on the anvil surface (i.e. the first diamond anvil surface) of the lower diamond anvil 14 by micromasking and magnetron sputtering. The thickness is 100-300 nm and it is arranged in a four-probe layout with a relative probe spacing of 10 μm to ensure stable electrical contact with the sample 15 to be tested.

[0060] The microstrip transmission line 11 is made of platinum and is laid at a fixed point on the anvil surface (i.e. the second diamond anvil surface) of the upper diamond anvil 10 through micro-manipulation transfer. It has a thickness of 2-6 μm and a width of 10-30 μm, spanning the sample cavity to ensure coverage of the active area of ​​the NV color center 16.

[0061] The sample chamber is surrounded by a rhenium sheet gasket 12 with a thickness of 250 μm. A through-hole with a diameter of 60-80 μm is formed in the center of the gasket 12 using laser drilling to serve as the placement area for the sample 15 to be tested. During testing, the sample 15, with dimensions of approximately 14 μm × 19 μm × 1 μm, is placed in the center of the chamber to ensure stable electrical contact with the metal thin-film electrode array 13. Potassium chloride crystals are used as the pressure-transmitting medium to uniformly transfer pressure. The two diamond anvils (i.e., the first and second diamond anvils) are lightly pre-pressed using the pressure screws of a diamond anvil press to complete the initial encapsulation. Figure 5 As shown, Figure 5 These are microscope images of the sample cavity from a diamond anvil cell. The left image is a top view (view from the top of the diamond anvil cell 10), and the right image is a bottom view (view from the bottom of the diamond anvil cell 14). Figure 6 The image shows a fluorescence scan of the NV center 16 in the sample cavity of a diamond anvil cell, as shown below. Figure 6 As shown, the dashed box represents the metal thin film electrode array 13, the solid box represents the sample to be tested 15, and the dotted-dash box represents the microstrip transmission line 11.

[0062] The in-situ air film pressurization unit uses a high-pressure helium cylinder as its gas source. It is connected to the air film sheet attached to the back of the diamond anvil via a precision pneumatic pressure controller and a high-pressure air circuit, thereby achieving in-situ, continuous, and stable pressure control.

[0063] Check the air circuit sealing of the in-situ air film pressurization unit to ensure there is no leakage at the connection between the air source and the air film. Simultaneously check the continuity and integrity of the signal connections between the metal thin film electrode array 13 and the electrical detection terminal 9, and between the microstrip transmission line 11 and the magnetic detection terminal 1.

[0064] Step 2: System integration, installation, and positioning.

[0065] Figure 1 This is a schematic diagram of the structural relationship of an in-situ electro-transport and quantum magnetic synergistic characterization system provided by the present invention, as shown below. Figure 1 As shown, the system adopts a split-architecture design. Considering that the vector superconducting magnet 4 will generate micro-vibrations during operation (especially when liquid helium cooling or compressor operation), and that magnetic detection based on photodetector magnetic resonance has extremely high requirements for optical path stability (micrometer-level focusing), this invention creatively places the vector superconducting magnet 4 independently on the magnet support frame 7, while the magnetic detection terminal 1 is mounted on the non-magnetic optical platform 3, and then the entire assembly, along with the extreme pressure device 2, is placed on the active vibration isolation platform 8. This structure, with the magnet suspended and the optomechanical vibration isolated, ensures the loading of a strong magnetic field while completely eliminating the interference of magnet vibration on precision optomagnetic measurements.

[0066] The system integration and installation process includes: such as Figure 1 As shown, the extreme pressure device 2, containing the sample 15 to be tested, is fixed inside the low-temperature constant temperature device 5. The low-temperature constant temperature device 5 is mounted on the triaxial displacement stage 6, and the entire triaxial displacement stage 6 and the magnetic detection terminal 1 are fixed together on the vibration isolation platform 8. At the same time, the vector superconducting magnet 4 is mounted on the magnet support frame 7, which is an independent structure from the vibration isolation platform 8 and the device mounted on it, and does not interfere with each other.

[0067] The positioning alignment process includes: operating the triaxial displacement stage 6 to adjust the spatial position of the extreme pressure device 2 so that the sample chamber area inside the extreme pressure device 2 is simultaneously located at the laser focus of the magnetic detection terminal 1 and the center of the uniform magnetic field area generated by the vector superconducting magnet 4.

[0068] Step 3: Constructing a multiphysics environment.

[0069] Start the multiphysics coupling module, and sequentially build and stabilize the extreme test environment:

[0070] High-pressure field loading and calibration are performed. The target pressure value is set through a pneumatic pressure controller, and the high-pressure gas is slowly injected into the gas film cavity through the pneumatic pressure controller of the in-situ gas film pressurization unit. In this example, the high-pressure gas can be, for example, high-pressure helium. The uniform expansion of the gas film drives the diamond anvil face of the diamond anvil to be pressed smoothly, realizing in-situ continuous pressurization of the sample 15 to be tested. During the pressurization process, the pressure is monitored in real time using a built-in pressure gauge (such as the peak shift of the R1 line of ruby ​​fluorescence). Once the pressure stabilizes at the target value, it is locked to maintain the pressure at the target value.

[0071] To construct and stabilize the low-temperature field, the liquid helium closed-loop refrigeration system was activated to cool the area where the sample 15 was located to the preset low-temperature target (such as any value in the range of 2.6K to 300K), and the temperature was kept stable at the target value ±0.01K.

[0072] For axial adjustment and loading of the magnetic field, the vector superconducting magnet 4 consists of three sets of superconducting coils orthogonally arranged along the X, Y, and Z axes, respectively. The X, Y, and Z axes are defined as follows: with the center of the uniform magnetic field region generated by the vector superconducting magnet 4 as the origin, the vertical direction is the Z-axis, and one set of superconducting coils generates a magnetic field component along the Z-axis. In the horizontal plane, a direction perpendicular to the Z-axis is the X-axis, and another set of superconducting coils generates a magnetic field component along the X-axis. Similarly, in the horizontal plane, a direction perpendicular to both the X and Z axes is the Y-axis, and a third set of superconducting coils generates a magnetic field component along the Y-axis. The maximum excitation current of a single coil is 65A, which can generate a continuously adjustable magnetic field of magnitude 0-1T in the sample cavity. The diameter of the uniform magnetic field region is not less than 10mm, and the magnetic field uniformity within this region is better than 3‰.

[0073] The vector superconducting magnet 4 is activated to generate an initial magnetic field of 200-300 Gs at the sample 15. A 532 nm laser is turned on (microwave off), and the fluorescence intensity of the NV color center 16 is monitored. By controlling the current in the three coils of the vector superconducting magnet 4, the direction of the magnetic field vector is finely adjusted until the fluorescence intensity reaches its global maximum value. At this point, the magnetic field direction is parallel to the axis of the NV color center 16 (deviation angle ≤ 0.3°). Maintaining this magnetic field direction, the magnetic field strength is increased to the required experimental magnetic field strength (target value adjustable from 0-1 T). Figure 7The ODMR spectrum of the shallow NV color center 16 on the diamond anvil cell facet of a diamond anvil cell at 6K and 47GPa is shown. Figure 7 The applied external magnetic field is 369.35 Gs, such as Figure 7 As shown, the intensity curve is the original data, and the fitted curve is the result obtained by Lorentz fitting the original data.

[0074] At this point, the precise construction of the "low temperature-directional strong magnetic field-high pressure" multi-physics field composite environment has been completed.

[0075] Step 4: Synchronous acquisition of magnetic and electrical signals.

[0076] Magnetic signal acquisition process: The magnetic detection terminal 1 emits a 532nm laser to excite the NV color center 16, and simultaneously applies microwave pulses with a frequency scanning in the range of 1GHz-6GHz through the microstrip transmission line 11. The fluorescence detector synchronously acquires the fluorescence signal, which is a fluorescence intensity signal of approximately 637nm. By scanning the microwave frequency, the optically detected magnetic resonance (ODMR) spectral lines are obtained and transmitted to the data processing module in real time.

[0077] Electrical signal acquisition process: A set current or voltage is applied to the sample 15 under test through the metal thin film electrode array 13 on the first diamond anvil cell surface of the diamond anvil cell, and the voltage or current response signal of the sample 15 under test is acquired synchronously and in situ, thereby obtaining electrical transport parameters such as resistance, Hall voltage, and magnetoresistance, which are then transmitted to the data processing module. Specifically, the electrical detection terminal 9 applies an excitation current of 1μA-10μA to the Fe3O4 sample 15 under test through the four-probe metal thin film electrode array 13 and measures the voltage response.

[0078] It is evident that the acquisition of magnetic signals and electrical signals are completely synchronized in time.

[0079] Step 5: Data parsing and correlation analysis. The data processing module parses the synchronously acquired magnetic and electrical signals.

[0080] The analysis of magnetic parameters includes: based on the Zeeman splitting principle of the ground state spin energy level of NV color center 16, analyzing the resonance frequency shift of the ODMR spectrum, and calculating the local magnetic field strength, magnetic susceptibility, quantum magnetic moment distribution, and other microscopic magnetic parameters of the sample 15.

[0081] The analysis of electrical parameters includes processing the collected current-voltage data to obtain electrical transport characteristics parameters such as resistivity, carrier concentration, mobility, and magnetoresistance of the sample under test 15.

[0082] Multi-parameter correlation includes: accurately correlating the resolved magnetic parameters with electrical parameters according to their synchronization time, thereby revealing in depth the physical mechanism of the interaction between charge and spin degrees of freedom in materials.

[0083] The analysis process will be further explained below.

[0084] The ODMR spectrum was Lorentz-fitted to obtain a double peak, and the resonance frequency shift was extracted to calculate the local magnetic field change ΔB of the 15 nearest neighbors of the sample. The calculation process is as follows:

[0085] NV color center 16 ground state spin ( 3 A2) m s =0 m s =+1、m s =0 m s The resonant frequencies of the two transitions =-1 satisfy the following: , The frequency difference is .

[0086] in:

[0087] m s Spin magnetic quantum number;

[0088] The zero-field splitting frequency of NV color center 16, in this embodiment It is 2.87GHz;

[0089] Electron gyromagnetic ratio, in this embodiment It is 2.80249514MHz / Gs;

[0090] B: The magnitude of the external magnetic field;

[0091] The angle between the external magnetic field and the 16-axis of the NV color center;

[0092] like Figure 7 As shown, the frequency difference between the two peaks The external magnetic field is 2.19039 GHz, parallel to the 16th axis of the NV color center, with θ = 0°. The local magnetic field variation ΔB in the nearest neighbor of sample 15 is the external magnetic field minus the applied magnetic field. The calculated local magnetic field variation in the nearest neighbor of sample 15 at 6 K 47 GPa is... B is 21.44 Gs.

[0093] The resistivity of sample 15 was obtained by processing the electrical signal. :

[0094] ;

[0095] in, ;

[0096] in:

[0097] ρ: Resistivity of sample 15, in Ω m;

[0098] d: Thickness of sample 15 to be tested;

[0099] ln2: The logarithm of 2 with the natural constant e as the base;

[0100] : The average resistance of sample 15 under test;

[0101] The resistance is measured by passing current through the first and second electrodes and measuring voltage through the third and fourth electrodes;

[0102] The resistance is measured by passing current through the second and third electrodes and measuring voltage through the fourth and first electrodes;

[0103] The resistance is measured by passing current through the third and fourth electrodes and measuring voltage through the first and second electrodes;

[0104] The resistance is measured by passing current through the fourth electrode and the first electrode, and measuring voltage through the second electrode and the third electrode.

[0105] Measured , , , The resistivity values ​​are 7.378Ω, 5.798Ω, 5.381Ω, and 3.013Ω, respectively. The calculated resistivity of sample 15 is approximately 2.33 × 10⁻⁶. -5 Ω m.

[0106] The four-probe metal thin-film electrode array 13 includes a first electrode, a second electrode, a third electrode, and a fourth electrode.

[0107] By plotting the correlation between the local magnetic field ΔB and resistivity of the sample 15 under more physical fields, the relationship between magnetism and charge transport of the relevant materials under high pressure and low temperature can be directly revealed.

[0108] Step 6: Multi-condition cycle test.

[0109] To study the material's response under different combinations of physical fields, a multi-physics coupling module is used to sequentially adjust the pressure (via the gas film pressurization unit), temperature (by adjusting the cooling power of the cryogenic isothermal device 5), and magnetic field strength or direction (via the vector superconducting magnet 4). After each parameter change and subsequent stabilization, steps three through five are repeated to collect a series of collaborative characterization data under multiple operating conditions, obtaining data such as the phase diagram or evolution law of the sample 15 under test.

[0110] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0111] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0112] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. An in-situ electro-transport and quantum magnetics co-characterization system, characterized in that, The system includes: A multiphysics coupling module, including an extreme pressure device, a vector superconducting magnet, and a cryogenic isothermal device, is used to construct a composite physical field environment to meet the requirements for characterizing the magnetoelectric properties of quantum materials under extreme conditions. The extreme pressure device includes a diamond anvil cell, which includes a nitrogen vacancy color center injected into the surface layer of the first diamond anvil cell and used as an embedded magnetic sensor, an electrical probe laid on the surface of the first diamond anvil cell, and a microstrip transmission line laid on the second diamond anvil cell and spanning the sample cavity. The collaborative detection module includes a magnetic detection terminal and an electrical detection terminal. The magnetic detection terminal is used to detect the magnetic signal of the sample under test using photodetector magnetic resonance. The electrical detection terminal uses a metal thin film electrode array to measure the resistance, Hall effect coefficient and magnetoresistive parameters of the sample under test in situ to characterize its electrical transport properties. The position adjustment and vibration isolation module includes a vibration isolation platform. The extreme pressure device and the magnetic detection terminal are rigidly fixed on the vibration isolation platform. The extreme pressure device and the magnetic detection terminal remain relatively stationary to ensure micron-level optical path alignment stability.

2. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 1, characterized in that, In the diamond anvil cell: The nitrogen-vacancy color centers are formed inside the surface layer of the first diamond anvil face through ion implantation, serving as an embedded magnetic sensor without occupying the surface space of the diamond anvil face. The electrical probe is a metal thin film electrode array, which is directly deposited or micromanipulated and transferred onto the surface of the first diamond anvil that has been injected with nitrogen vacancy color centers through micro-nano fabrication technology. The microstrip transmission line is used for microwave manipulation of the nitrogen-vacancy color centers. It is laid on the second diamond anvil and spans the sample cavity through micro-nano fabrication technology or micro-manipulation transfer.

3. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 2, characterized in that, The extreme pressure device includes a spatially integrated diamond anvil cell and an in-situ air film pressurization unit. The diamond anvil cell is mounted on the pressurization base of the in-situ air film pressurization unit via a diamond anvil cell press. The in-situ air film pressurization unit is used for in-situ continuous pressure regulation under low temperature and strong magnetic field environments. The in-situ air film pressurization unit includes an air source, a pneumatic pressure controller, a high-pressure air path, a pressurization base, and an air film sheet. The air film sheet is located between the pressurization base and the non-diamond anvil face of the diamond anvil cell. The internal cavity of the air film sheet is connected to the pneumatic pressure controller and the air source through the high-pressure air path. The low temperature is a temperature below a predetermined temperature threshold, and the strong magnetic field is a magnetic field strength above a predetermined magnetic field strength threshold.

4. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 1 or 3, characterized in that, The position adjustment and vibration isolation module also includes a three-axis displacement stage and a non-magnetic optical platform for adjusting the relative position of the sample to be tested and the magnetic detection terminal. The extreme pressure device is installed on the three-axis displacement stage and then mounted to the vibration isolation platform through the three-axis displacement stage. The magnetic detection terminal is installed on the non-magnetic optical platform and then mounted to the vibration isolation platform through the non-magnetic optical platform.

5. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 4, characterized in that, In the multiphysics coupling module: The vector superconducting magnet is independently mounted on an external magnet support frame and physically separated from the magnetic detection terminal to block the transmission of vibrations generated when the magnet is working, and is used to generate a magnetic field of predetermined size and direction at the sample chamber of the extreme pressure device. A low-temperature thermostat is installed on the triaxial displacement stage to maintain a constant temperature of the sample to be tested in the sample chamber of the extreme pressure module. The extreme pressure device is vertically installed and fixed on the cold head inside the cold cavity of the cryogenic constant temperature device. The central axis of the vector superconducting magnet is arranged coaxially with the central axis of the sample cavity of the extreme pressure device. An isolation gap is reserved between the vector superconducting magnet and the cryogenic constant temperature device to prevent the vibration of the vector superconducting magnet from being transmitted to the extreme pressure device through the cryogenic constant temperature device.

6. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 5, characterized in that, In the collaborative detection module, the magnetic detection terminal employs photodetector magnetic resonance via a 532nm laser source, a microwave source, and a fluorescence detector, comprising: The 532nm laser source, the microwave source, and the fluorescence detector are coaxially arranged on the non-magnetic optical platform; The pump light output from the 532nm laser source is focused into the sample cavity after being modulated by a polarizer and a waveplate, and is used to initialize the spin polarization of the nitrogen vacancy color center. The microwave source introduces microwave pulses into the sample chamber of the extreme pressure device via a radio frequency coaxial line, driving the spin to undergo resonant transition. The fluorescence detector collects the fluorescence signal emitted during the spin relaxation of the nitrogen vacancy color center, which is then converted into an electrical signal by a photomultiplier tube and input into the data acquisition system. The 532nm laser source, the microwave source, and the fluorescence detector are triggered and synchronized by a timing synchronization controller to jointly complete the signal excitation and detection of optical magnetic resonance. The triaxial displacement stage and the magnetic detection terminal are fixed together on the vibration isolation platform.

7. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 6, characterized in that, In the collaborative detection module, the electrical detection terminal uses a metal thin-film electrode array connected to the sample to be tested for in-situ measurement of resistance, Hall effect, and magnetoresistive parameters, wherein: The electrical detection terminal adopts a four-wire layout. The metal thin film electrode array prepared by micro-nano fabrication is in ohmic contact with the surface of the sample to be tested. An excitation current is applied by a current source, and the voltage response of the sample to be tested is collected synchronously by a voltmeter to perform in-situ measurement of resistance, Hall effect and magnetoresistive parameters.

8. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 7, characterized in that, The spatial position of the extreme pressure device is adjusted by the triaxial displacement stage so that the sample chamber inside the extreme pressure device is located at the laser focus of the magnetic detection terminal and at the center of the uniform magnetic field region generated by the vector superconducting magnet, so that the central field of the suspended vector superconducting magnet, the optical path focus of the magnetic detection terminal, and the sample chamber coincide in space.

9. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 8, characterized in that, The vector superconducting magnet consists of three sets of superconducting coils used to generate a magnetic field. The direction of the generated magnetic field is determined by monitoring the maximum fluorescence intensity of the nitrogen-vacancy color centers under microwave-free conditions, ensuring that the magnetic field remains parallel to the axis of the nitrogen-vacancy color centers within the first diamond anvil.

10. The in-situ electrical transport and quantum magnetics co-characterization system according to claim 3, characterized in that, The in-situ pressurization process of the in-situ gas film pressurization unit is as follows: the gas film has a sealed cavity inside, and the sealed cavity is connected to the pneumatic pressure controller and the gas source through a high-pressure gas path. The pneumatic pressure control is used to regulate the output of high-pressure gas from the gas source. The high-pressure gas is injected into the cavity of the gas film through the high-pressure gas path so that the gas film expands uniformly to pressurize the sample chamber in situ.

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