63 results about "Zero field" patented technology

The invention belongs to the technical field of quantum precision sensing, and particularly relates to an NV color center magnetic detection or temperature measurement method based on a zero field splitting coefficient, which is characterized in that a hypothetical magnetic field vector is calculated according to lattice structure characteristics of a diamond regular tetrahedron, and the zero field splitting coefficient is calculated according to the amplitude of the vector. Frequency deviation introduced by the transverse magnetic field is fully considered, and the accuracy is improved on the basis of the steps. Compared with an existing method, the calculated zero field splitting coefficient is more accurate, an error analysis method is provided, and magnetic field measurement or temperature measurement can be achieved through a more accurate D value by means of the method.

The invention provides a method and a system for improving the receiving bandwidth of a very-low-frequency atom magnetometer. The method comprises the following steps of: polarizing alkali metal atoms in an atom gas chamber along the direction of driving laser by using the driving laser; an external magnetic field at the air chamber is compensated through a three-axis magnetic coil and a three-axis magnetic sensor, a zero field environment is provided, and a main magnetic field B is applied by the coil in the direction of driving light; detecting the precession of the spin projection signal of the polarized atom in the x direction by using the detection laser in the x direction; an external very-low-frequency signal interacts with atoms polarized in the z direction to enable the atoms to generate precession signals on the xOy plane, and therefore the external very-low-frequency signal is detected by detection light. After detection optical signals are collected, the control system feeds back the signals to the atom ensemble through the coil in a damping magnetic field mode, the bandwidth of the system is expanded by adjusting feedback parameters, and meanwhile the sensitivity is kept unchanged. According to the technical scheme, the technical problem that high sensitivity and high bandwidth cannot be achieved at the same time in a very-low-frequency atom magnetometer in the prior art is solved.

The invention provides a self-calibration three-axis atom magnetometer capable of achieving vector and scalar integrated measurement. The magnetometer comprises a sensor probe and an electronics box. A laser generating unit in the electronics box generates a single beam of pumping laser to act on an alkali metal atom gas chamber in the sensor probe. According to the alkali metal atom zero field resonance principle, the pumping laser and alkali metal atoms interact to generate a light absorption signal containing environment magnetic field information. A photoelectric detection unit in the electronics box converts an optical signal into an electric signal, a three-axis modulation compensation circuit is used for demodulating the photoelectric signal and generating a compensation signal, and three-axis precision measurement of the magnetic field is achieved. The magnetometer can work in an Mz mode or a CPT mode, scalar measurement of a magnetic field is achieved, and therefore self-calibration of the three-axis vector of the magnetometer is achieved. By switching the measuring ranges, high-sensitivity and long-term accurate three-axis omnidirectional magnetic field measurement can be realized under different measuring ranges.

The invention relates to a magnetorheological fluid and a preparation method and application thereof.The magnetorheological fluid contains polysiloxane surface modified magnetic particles, polysiloxane is obtained by polycondensation of at least one silane with the general formula being X-Si-(OR) 3, X is selected from substituted or unsubstituted alkyl with the carbon atom number being 10-16, and R2 is selected from substituted or unsubstituted alkyl with the carbon atom number being 10-16. R is selected from substituted or unsubstituted alkyl with the carbon atom number of 1-3, and the weight-average molecular weight of polysiloxane is 500-20000. The magnetorheological fluid disclosed by the invention has relatively low zero-field viscosity, relatively high shear yield stress and long-term stability, is particularly suitable for a vehicle damping system, has the capabilities of quick response and damping adjustment, and is beneficial to improving the performance of the damping system and prolonging the service life of the damping system.

The invention provides a high-sensitivity magnetic field measurement method based on a quantum measurement principle and a related device, and belongs to the technical field of magnetic field measurement. The method comprises the following steps: correcting a zero field splitting parameter by using an initial magnetic field to enhance the stability of compression strength, and driving an NV cluster to generate a spinning compression state through microwaves to obtain a compression state probe; taking the compressed-state probe as an initial state of the quantum probe, and performing space-time polarization modulation decoupling on the target magnetic field and the environment magnetic field to obtain a decoupling signal; performing quantum phase-locked interference processing on the decoupling signal and a given reference microwave frequency to obtain a frequency shift signal; and performing magnetic field integral reconstruction and sensitivity calibration by using the frequency shift signal and combining the compression parameter of the compressed probe to obtain a final target magnetic field at the detection moment. Based on the quantum measurement principle, in combination with quantum coherent regulation, space-time modulation decoupling and the like, accurate extraction of the target magnetic field can be realized in a high electromagnetic interference environment, and the measurement sensitivity and accuracy are improved.

The magnetorheological fluid comprises an ionic liquid, a basic liquid, magnetic particles and an additive, and is characterized in that the magnetorheological fluid contains imidazole cations, the general formula of the imidazole cations is [R1R2N +] C3H4, R1 is selected from substituted or unsubstituted alkyl with the carbon atom number of 1-10, and R2 is selected from substituted or unsubstituted alkyl with the carbon atom number of 1-10. The magnetorheological fluid disclosed by the invention has excellent sedimentation stability, relatively low zero-field viscosity and relatively high shear yield stress.

The invention belongs to the technical field of magnetorheological fluid preparation, and particularly relates to iron-cobalt nanoparticles, a preparation method of the iron-cobalt nanoparticles and application of the iron-cobalt nanoparticles in magnetorheological fluid. The iron-cobalt nanoparticles contain iron and cobalt, are amorphous and spherical, and have an average particle size of 20-35 nm. The iron-cobalt nano-particles are excellent in magnetization performance, the saturation magnetization of the iron-cobalt nano-particles can reach 220 emu / g, and compared with ferromagnetic nano-particles, the saturation magnetization of the iron-cobalt nano-particles can be improved by 44.7%. Moreover, the magnetorheological fluid prepared on the basis of the iron-cobalt nanoparticles is excellent in performance, the zero-field viscosity of the magnetorheological fluid can be as low as 0.63 Pa.s, and the maximum shear stress corresponding to the shear rate of 0.1 s <-1 > under a 1T magnetic field can reach 68KPa.

The invention relates to the technical field of magnetic materials, and discloses a binuclear dysprosium single-molecular magnet and a preparation method thereof. The high-yield [Dy2L2 (MeOH) 2 (NO3) 2)]. 3MeOH is prepared by adopting a room-temperature volatilization method, and compared with methods such as high-temperature and high-pressure solvothermal synthesis and poor solvent diffusion, the method has the advantages of simple reaction conditions, easiness in operation, convenience and the like. The crystal structure of the binuclear dysprosium single-molecule magnet material is a triclinic system, the space group is P-1, and the cell parameters are as follows: # imgabs0 # imgabs1 #, alpha is equal to 109.4020 (10) degrees, beta is equal to 93.1900 (10) degrees, and gamma is equal to 98.2070 (10) degrees; the binuclear dysprosium single-molecule magnet synthesized by the method can show typical slow relaxation behavior in a zero field, has the characteristics of a single-molecule magnet, and can be applied to the fields of quantum calculation and ultrahigh-density information storage.

The present invention relates to a method for determining the coupling between magnetometers in an array of N magnetometers (e.g., by means of an optically pumped magnetometer), wherein each magnetometer includes a field cancellation system that can be enabled to operate the magnetometer in a zero field. The method includes a first phase (P1), in which the N magnetometers are divided into N - 1 magnetometers with the field cancellation system deactivated and one measuring magnetometer with the field cancellation system activated. The first phase includes: - generating (GENj) by these magnetometers a plurality of reference magnetic fields with known amplitudes and different directions, - measuring (MESi) by the measuring magnetometer the ambient magnetic field on a plurality of measurement axes, - determining (CALCij) the coupling coefficient between the measuring magnetometer and each of the N magnetometers based on the measured values and these known amplitudes.

The invention relates to a laser-assisted regulation tunnel magnetoresistive sensor, a preparation method thereof and a zero field regulation method. The tunnel magnetoresistive sensor includes: a substrate; a multi-film structure formed on the substrate, wherein the multi-film structure comprises a magnetic tunnel junction and a spin current generation layer which are stacked; the magnetic tunnel junction is arranged close to the substrate; the laser transmission layer is formed on the multi-film structure, and the laser transmission layer has a laser transmission property. According to the embodiment of the invention, the magnetic anisotropy potential barrier can be reduced, so that the current density required by pulse current regulation and control is reduced, and the power consumption is reduced.

The invention provides an input current optimization method based on MPI orthogonal model constant-speed rotary scanning, which aims at a rotary scanning device formed by combining two zero field line devices constructed by two groups of coils, and comprises the following steps of: controlling the input current of the two groups of coils which generate mutually vertical zero field lines to be periodic current; therefore, the fusion null field line generated by the rotary scanning device is controlled to perform periodic constant-speed rotation so as to determine the position of the fusion null field line at any moment. According to the method, the problem that the FFL of an existing selected model rotates irregularly can be solved, the effect of uniform-speed scanning is achieved, the position of the FFL is controllably observed, and the controllability of MPI is improved.

The present application provides a self-calibrating three-axis atomic magnetometer for realizing integrated vector and scalar measurement. The magnetometer includes a sensor probe and an electronics box. A single-beam pump laser generated by a laser generating unit in the electronics box acts on an alkali metal atomic gas cell in the sensor probe. According to the zero-field resonance principle of alkali metal atoms, the pump laser interacts with the alkali metal atoms to generate an optical absorption signal containing environmental magnetic field information. A photoelectric detection unit in the electronics box converts the optical signal into an electrical signal, and a three-axis modulation compensation circuit demodulates the photoelectric signal and generates a compensation signal to achieve precise three-axis measurement of the magnetic field. The present invention can make the magnetometer operate in the Mz mode or the CPT mode to realize scalar measurement of the magnetic field, thereby realizing self-calibration of the three-axis vector of the magnetometer. By switching the measurement range, the present invention can achieve high-sensitivity and long-term accurate three-axis omnidirectional magnetic field measurement at different measurement ranges.

The invention discloses a multi-core J coupling constant-based pH measurement method, which comprises the following steps of: 1, preparing a series of compound samples with different pH values, and measuring J coupling constants of compounds in the samples; 2, drawing a coupling constant and pH relation curve of the compound J, and deducing a pH calculation formula; and 3, measuring the J coupling constant of the compound-containing sample to be measured, and determining the pH value of the sample to be measured. According to the method, the J coupling constant is measured through a nuclear magnetic resonance spectrum method or a zero field-near zero field J coupling spectrum method, and the pH value of the surrounding environment of the compound can be measured.

The invention provides amorphous magnetic particles and a preparation method thereof, magnetorheological fluid and a preparation method and device thereof. The coercive force of the amorphous magnetic particles provided by the invention is less than 1Oe; the saturation magnetization of the amorphous magnetic particles is greater than or equal to 160 emu / g. According to the amorphous magnetic particles provided by the invention, the magnetorheological fluid has relatively high stability, low zero field viscosity and high shear yield stress under a magnetic field.

The application relates to the technical field of simulation calculation and discloses a hysteresis loop simulation method based on mumax3, which comprises the following steps: obtaining the parameters of a magnetic material, and establishing a simulation model according to the parameters of the magnetic material; applying a field strength to the simulation model to obtain a fully saturated state of the magnetic material; applying a cosine-type field strength gradually decreasing with time in a peak value to the simulation model in the saturated state, and simultaneously performing LLG equation solving until the field strength peak value is reduced to below a preset threshold value, and taking the corresponding magnetic moment state as a zero field strength state; applying an alternating field strength to the simulation model in the zero field strength state, and simultaneously performing LLG equation solving calculation to complete loop simulation, so that a hysteresis loop is obtained. The magnetic material in the saturated state is demagnetized, the magnetic moment distribution of a demagnetized state under the zero field strength which is in line with the actual physical situation is obtained, and the state is taken as the basis of Mumax3 micromagnetic simulation calculation, so that a hysteresis loop with higher precision can be obtained.

The invention provides a semimetal compensation ferrimagnetic material, the chemical formula of the semimetal compensation ferrimagnetic material is CrFeS2, the semimetal compensation ferrimagnetic material has a hexagonal NiAs type crystal structure and belongs to a 194 space group, and a preparation method of the semimetal compensation ferrimagnetic material comprises the following steps: packaging Cr powder, Fe powder, a sulfur block and a transmission medium iodine in a vacuum quartz tube; and placing in a heating furnace, heating at 780-920 DEG C for 4-30 days, and then quenching to a greenhouse. The semimetal compensation ferromagnetic material provided by the invention simultaneously has the characteristics of great perpendicular magnetic anisotropy and magnetic compensation characteristic, so that the material can realize zero-field cold large exchange bias, and the direction of the exchange bias can be regulated and controlled by unidirectional magnetic fields with different sizes, so that the semimetal compensation ferromagnetic material has a wide application prospect in the field of spintronics.

The present invention discloses a zero-field-cooled room-temperature exchange bias permanent magnet material, which is composed of two rare earth elements Pr and Gd, and Co element. First, a cast Pr-Gd-Co compound is obtained through melting, and then a Pr-Gd-Co thin strip, that is, the zero-field-cooled room-temperature exchange bias permanent magnet material, is obtained through melt spinning. The atomic ratio satisfies 1:3, and the chemical formula is Pr 1‑ x Gd x Co3, where the value range of x is 0.2 ≤ x ≤ 0.8; the Curie temperature ranges between -400 K and 550 K; the phase structure is a rhombohedral PuNi3-type crystal structure. Its preparation method includes: 1. Preparation of the cast Pr-Gd-Co compound; 2. Preparation of the zero-field-cooled room-temperature exchange bias permanent magnet material. As an application of the permanent magnet material, at room temperature, when the external magnetic field is 2 T, the coercivity is 1.37 - 12.88 kOe; the exchange bias field is 0.2 - 5.38 kOe; at 10 K, when the external magnetic field is 5 T, the coercivity is 16.47 - 36.23 kOe; the exchange bias field is 2.73 - 14.92 kOe. The advantages of the present invention are that it has large coercivity, strong exchange bias field under zero-field-cooled conditions, good temperature stability, and simple process.

The invention belongs to the technical field of condensed state physics and material research, and particularly relates to a heavy rare earth transition metal oxide magnetocaloric material screening method which comprises the following steps: obtaining zero field cooling of a test sample and a magnetization intensity-temperature curve of the field cooling, and deriving the magnetization intensity-temperature curve of the field cooling to obtain a magnetic field temperature curve of the field cooling; then the absolute value of the derivative of the field cooling magnetization intensity-temperature curve is obtained, and an absolute value curve is obtained; calculating an average magnetic phase transition temperature based on the absolute value curve; calculating the variance of the absolute value curve at the average magnetic phase transition temperature; calculating the dimensionless variance of the absolute value curve based on the variance of the absolute value curve at the average magnetic phase transition temperature; obtaining an isothermal magnetization curve of the test sample and calculating a magnetic entropy change value; and based on the dimensionless variance value, establishing a quantitative relationship between the magnetic phase change interaction intensity and the magnetic entropy change value, and further screening out a target sample. And theoretical support is provided for development and physical mechanism analysis of the low-temperature heavy rare earth based giant magnetocaloric material.

The present application relates to a kind of cobalt-based spinel ferrite nanoparticles with zero-field magnetic quantum tunneling properties and its application, the inside of the nanoparticle has the topological structure of broken spatial symmetry;The topological structure includes the first topological domain and the second topological domain distributed staggeredly in space, so that the cobalt-based spinel ferrite nanoparticle produces intrinsic transverse tunneling energy level splitting under zero applied magnetic field.The sharp stepwise magnetization jump of the cobalt-based spinel ferrite nanoparticle of the present application at zero field can realize the high sensitivity nonlinear response to weak magnetic field, and can be applied to the preparation and development of low-temperature quantum sensing probe or multi-level nonvolatile logic memory.

A spin-orbit torque (SOT) magnetic device with synthetic antiferromagnetic (SAF) structure, including a SOT layer for providing a spin current, a SAF structure composed of a first ferromagnetic layer, a nickel oxide (NiO) exchange coupling layer and a second ferromagnetic layer, and a capping layer on the SAF structure. This magnetoelectric device of oxide SAF structure can achieve zero-field switching through current-induced SOT, and can be used as the free layer of a magnetoresistive random access memory (MRAM).

The invention discloses a zero-field spin-orbit moment memory with a ferromagnetic layer component gradient structure and a preparation method thereof, the core structure of the memory comprises a CoFeB ferromagnetic layer with a vertical component gradient, and magnetic moments at two sides of a domain wall generate asymmetry in amplitude or orientation by regulating and controlling gradient distribution of Co, Fe and B elements and inducing non-uniform Dzyaloshiski-Moriya interaction (DMI); furthermore, domain wall chiral characteristics are weakened, a net effective field is formed, and deterministic magnetization overturning without assistance of an external magnetic field is finally realized. In the preparation process, a magnetron sputtering technology is adopted, a heavy metal strong spin orbit coupling layer, a vertical magnetic anisotropy magnetic free layer with component gradient, a tunnel barrier layer, a magnetic vertical reference layer, an artificial antiferromagnetic pinning layer and a covering layer are stacked in sequence, and a magnetic tunnel junction (MTJ) unit is prepared through annealing and micro-nano processing technologies. The invention provides an efficient solution for the research and development of controllable magnetic memories and logic devices, and has a wide application prospect in the field of high-density magnetic memories.

The invention discloses a medium entropy alloy material with zero-field cold exchange bias effect and a preparation method thereof. The chemical formula of the material is Mn 2‑x FeCoNi, 0.2≤x≤0.4, firstly obtain Mn by repeated smelting 2‑x The FeCoNi alloy is then sealed in a vacuum quartz tube and placed in a muffle furnace for annealing. 2‑ x The FeCoNi medium-entropy alloy material has a zero-field cold exchange bias effect. The size of its ferromagnetic and antiferromagnetic exchange coupling can be controlled by changing the Mn composition (0.2≤x≤0.4) to obtain a specific antiferromagnetic and ferromagnetic coupling ratio, thereby obtaining an obvious zero-field cold exchange bias field without the need for an additional external magnetic field accompanying the cooling process. This material has potential application prospects in spin electronics fields such as magnetic storage units and spin valve devices.

The invention discloses a vertical magnetic anisotropy GaN-based spin polarized light emitting diode and a preparation method thereof, and the core of the preparation method is as follows: firstly, converting 1-3 layers of graphene into a circular ring shape on n-GaN through dry transfer and laser direct writing; and secondly, in an ultrahigh vacuum environment, continuously and sequentially sputtering and depositing an MgO tunneling layer, a single-layer CoFeB ferromagnetic layer with vertical magnetic anisotropy and an ITO transparent conductive layer in the same sputtering cavity without breaking vacuum. According to the invention, an inverted structure is utilized to enhance heat dissipation and optimize a spin injection interface, and polarized light observation easy to observe is realized. Meanwhile, graphene is used for blocking the defect of MgO, conductance mismatch is solved, spin injection efficiency is enhanced, zero-field perpendicular magnetic anisotropy is achieved through single-layer CoFeB, ITO serves as a conducting layer and also serves as a light window, a full-vacuum magnetron sputtering process is combined to guarantee atomic-scale interface cleanness, and finally the device obtains high-spin-polarization polarized light at the room temperature under the zero external magnetic field; and meanwhile, the spin injection efficiency is high, the spin service life is long, the operation is stable under high current density, the process is simplified, the cost is low, and the observation is easy.

The application relates to a mouse heart magnetocardiography and magnetoencephalography testing device and method based on a zero-field atomic magnetometer, and relates to the field of heart magnetocardiography and magnetoencephalography testing. The application solves the problems that the existing mouse heart magnetocardiography and magnetoencephalography testing device has a large volume, and the magnetic field signal is distorted due to the movement or struggle of the mouse, and motion artifacts are generated. A plurality of groups of tool fixing hole positions (1-1) are formed in pairs on the upper end face of a platform (1), a plurality of heart magnetometer mounting holes (1-2) are formed in the middle of the length direction of the lower end face of the platform (1), a heart magnetometer is mounted in the heart magnetometer mounting hole (1-2), one insert (2) is inserted in each group of tool fixing hole positions (1-1), the insert (2) is provided with a magnetoencephalography mounting hole (2-1) and a head mounting hole (2-2). The mouse heart magnetic signal and the magnetoencephalography signal are tested at the same time, and the error introduced by the environmental magnetic field change in the experiment process is reduced to the maximum extent. The application is used for mouse heart magnetocardiography and magnetoencephalography testing.

The present invention relates to a method, device, and medium for calculating AC loss in a superconducting cable. The method comprises obtaining superconducting cable operating data and structural parameters; calculating the horizontal and vertical components of the external magnetic field of each layer of strip at a constant critical current density using the operating data and structural parameters based on the Kim extended magnetic field effect; calculating the critical current density of the corresponding layer of strip and updating the zero-field region width parameter of the corresponding layer; obtaining the current density distribution; updating the vertical component of the strip's external magnetic field; and calculating the AC loss of the superconducting cable based on the updated zero-field region width parameter and the vertical component of the strip's external magnetic field. The device and medium are used to implement the above method. Compared with the prior art, the present invention simplifies the calculation of AC loss into a single item, making the calculation more accurate.

The invention discloses a Fe2O3 buffer layer-based magnetic random access memory capable of realizing directional overturning of a magnetization layer without an external magnetic field and driven by a vertical magnetic layer current, and belongs to the field of spintronics. The structure of the device sequentially comprises an antiferromagnetic layer Fe2O3, a spin current generation layer Pt, a magnetic layer Co with vertical anisotropy and a protective layer TaOx for preventing a thin film from being oxidized from bottom to top. Due to the addition of the antiferromagnetic layer Fe2O3, magnetization overturning can be induced to be free of external field. According to the invention, the insulated Fe2O3 is used as the buffer layer to be inserted into the Pt / Co system, so that not only can zero field flip be realized, but also the problem of increase of critical flip current of the device caused by a shunting effect due to introduction of the functional layer can be avoided. The invention provides a structure and a preparation process of a current-driven magnetization turnover device based on an insulating antiferromagnetic layer.

The application discloses a method for precisely compensating three-dimensional residual magnetism of a single-beam SERF atomic magnetometer, which is based on the principle of high-frequency magnetic field modulation and comprises the following steps: after rough compensation of three-dimensional residual magnetism of a single-beam SERF magnetometer based on a quasi-static magnetic field, performing precise compensation of three-dimensional residual magnetism, wherein the precise compensation of three-dimensional residual magnetism comprises the following steps: applying a high-frequency modulation magnetic field, respectively scanning XYZ three-axis magnetic fields, and making the zero-crossing point of a dispersion curve corresponding to a demodulated first-order harmonic coincide with a zero-field point, so as to realize precise magnetic field compensation of a single-beam SERF magnetometer system. The method effectively improves the precision of magnetic compensation, solves the problems that a traditional magnetic compensation mode is not applicable to a single-beam SERF atomic magnetometer or the precision of magnetic field compensation in the direction of pumping light is too low, and is reasonable and simple to operate, thus playing a great promoting role in the development of atomic magnetometers.

A device for guiding TEM waves using dielectric nanowires is disclosed, relating to the fields of nanotechnology and microwave technology. The device structure includes a substrate, a zinc oxide seed layer, a ground signal electrode, a transmission signal electrode, and zinc oxide nanowires, forming a coplanar waveguide structure. The dielectric nanowires replace the signal lines in traditional coplanar waveguide structures. The TEM signal fed to one electrode is guided by the nanowires to the other signal electrode, ensuring that the electric field is along the normal direction of the nanowire surface and the magnetic field is along the tangential direction. Under the influence of the external electric field and the Lorentz force, the space charge region of the nanowire undergoes dynamic polarization, achieving internal zero field and surface electromagnetic shielding, thereby guiding the TEM wave. This coplanar waveguide structure design ensures good guidance performance at frequencies above 10 GHz.

The invention relates to a magnetic nanoparticle concentration omnibearing scanning method based on a zero field line, and the method comprises the following steps: S1, selecting a method for detecting the concentration of magnetic nanoparticles according to the magnetization characteristics of the magnetic nanoparticles; s2, determining to adopt a zero field line device to generate a zero field line so as to detect the concentration of the magnetic nanoparticles; s3, a zero field line device capable of generating a zero field line is built through a plurality of coil combinations; s4, an existing model is improved, and coil configuration is adjusted to achieve omni-directional detection; and S5, verifying whether the performance of the new model meets actual requirements or not. The method can solve the problem that errors exist when the zero field line is controlled to rotate in the prior art.

The application provides a method and system for improving the receiving bandwidth of a very low frequency atomic magnetometer, which polarizes alkali metal atoms in an atomic cell along the direction of a driving laser by using the driving laser; an external magnetic field at the cell is compensated by a three-axis magnetic coil and a three-axis magnetic sensor to provide a zero-field environment, and a main magnetic field B is applied to the coil in the direction of the driving light; the precession of the spin projection signal of the polarized atoms in the x direction is detected by using a detection laser in the x direction; an external very low frequency signal interacts with the atoms polarized in the z direction to make the atoms produce a precession signal in the xOy plane, so that the detection light is detected. After the detection light signal is collected, the control system feeds back a damping magnetic field to the atomic ensemble through the coil, and the bandwidth of the system is expanded by adjusting the feedback parameters while keeping the sensitivity unchanged. The technical scheme of the application solves the technical problem that high sensitivity and high bandwidth cannot be achieved simultaneously in the prior art.