17 results about "Zero field" patented technology

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 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.

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 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 the technical field of quantum materials, in particular to a van der Waals heterojunction type high-efficiency superconducting diode and a preparation method and application thereof. The superconducting diode comprises a substrate layer, an electrode layer, an Ising superconducting layer, a magnetic material layer and a packaging layer which are sequentially stacked from bottom to top; or, the superconducting diode comprises a substrate layer, a magnetic material layer, an Ising superconducting layer, an electrode layer and a packaging layer which are sequentially stacked from bottom to top. A heterojunction is formed by the Ising superconducting layer and the magnetic material layer to realize double symmetry cooperative breaking, and a system capable of realizing high-efficiency superconducting diode effect (SDE) is constructed by combining a vertical magnetic field training technology; wherein, the magnetic material layer breaks time reversal symmetry, and the Ising superconducting layer and the magnetic material layer form a heterojunction to break spatial inversion symmetry. The superconducting diode can maintain super-high SDE efficiency under zero field and has strong zero-field stability.

The application discloses a spin terahertz emitter with adjustable polarization without an external magnetic field and a manufacturing method thereof. A metal thin film layer heterostructure is deposited on a surface of a glass substrate. A ferromagnetic layer is a FeNi thin film layer, an anti-ferromagnetic layer is an IrMn3 thin film layer, and an interface between the FeNi thin film layer and the IrMn3 thin film layer is an exchange coupling interface subjected to directional magnetic field induction treatment. A surface of the metal thin film layer heterostructure is a periodic stripe array structure. The manufacturing method comprises the following steps: a magnetron sputtering process is used to sequentially deposit a ferromagnetic layer, an anti-ferromagnetic layer and a protective layer; the exchange coupling interface is formed through directional magnetic field induction treatment; and a micro-nano processing process is used for patterning treatment. Beneficial effects are as follows: under the condition of no external magnetic field, reliable spin current generation, spin-charge conversion and terahertz radiation can be realized. The stripe patterning structure realizes linear polarization, elliptical polarization and near-circular polarization output. The 'zero-field emission function' and the 'polarization control function' are integrated in the same thin film device system, and the system complexity is reduced.

The invention provides a solid-state spin zero-field magnetic resonance temperature measurement method and system. The method comprises the following steps: an IQ modulator modulates an intrinsic signal vt according to a baseband low-frequency I (t) signal and a baseband low-frequency Q (t) signal, generates a composite dual-frequency microwave containing two resonant frequencies, and applies the composite dual-frequency microwave to a diamond sample; the diamond sample outputs a fluorescence signal and acts on the lock-in amplifier, the waveform generator outputs a reference signal to the lock-in amplifier, and the pulse transmitter performs sequential control on the microwave signal source and the lock-in amplifier; the lock-in amplifier outputs a lock-in amplifier output signal according to the fluorescence signal and the reference signal; performing data processing on the output signal of the lock-in amplifier to obtain a temperature field variation; and according to a reference temperature and the temperature field variable quantity, calculating and obtaining a solid-state spin zero field magnetic resonance temperature measurement result. By applying the technical scheme of the invention, the technical problem that the quantum precision measurement sensitivity based on solid-state spin magnetic resonance is limited by multi-physics field coupling in the prior art is solved.

The invention discloses low-zero-field-viscosity magnetorheological fluid as well as a preparation method and application thereof, and belongs to the technical field of intelligent materials and vehicle braking. The magnetorheological fluid is prepared from, by weight, 20%-30% of carbonyl iron powder, 1%-3% of a composite additive and the balance dimethyl silicone oil. The density is 3.0-3.2 g / ml, the working temperature is-40 DEG C to 150 DEG C, the zero magnetic field viscosity is smaller than or equal to 0.25 Pa.s at the shearing rate of 1000 / s, and the shearing yield stress is larger than or equal to 43 kPa under the magnetic field of 0.5 T. The preparation method comprises the steps of raw material preparation, preliminary mixing, vacuum stirring at the vacuum degree of not lower than-0.09 MPa and the temperature of 20-30 DEG C, post-treatment detection and the like. The magnetorheological fluid balances low zero field viscosity and high shear yield stress, has excellent sedimentation stability and wide temperature adaptability, and can remarkably reduce no-load loss and improve braking response speed, torque output precision and system reliability when being used for the vehicle magnetorheological fluid retarder.

An ellipsometric atomic magnetometer-based magnetic field in-situ monitoring and automatic compensation device and method enable the magnetometer to automatically trigger an online magnetic field compensation program in a timely manner according to the monitoring result of the environmental magnetic field, and then restore the environmental magnetic field to zero field, thereby improving the ability of the magnetometer to resist changes in the environmental interference magnetic field, enabling the magnetometer to work stably for a long time without the need for manual zeroing of the magnetic field. The present application additionally collects the previously unused second harmonic component on the basis of the original magnetometer collecting the first harmonic component for magnetic field measurement, and realizes real-time monitoring of the three-axis magnetic field by comparing the difference between the value of the current second harmonic component and the value of the second harmonic component in a zero-field environment; the intelligent optimization algorithm is combined with the second harmonic component to realize online high-precision magnetic field compensation of three axes simultaneously with a low sampling point number, improve the compensation efficiency, and ultimately improve the long-term stability and magnetic field interference resistance of the magnetometer without affecting the original measurement sensitivity.

The invention relates to the technical field of magnetorheological fluids, and discloses a double-dispersion magnetorheological fluid and a preparation method thereof.The double-dispersion magnetorheological fluid comprises a dispersion phase and a dispersion medium, and the dispersion phase is evenly dispersed in the dispersion medium; the dispersion phase is formed by compounding FeCo alloy nanoparticles and NiXFe1-XFe2O4 micron particles, and the dispersion medium is a mixed base solution formed by mixing dimethyl silicone oil and poly-alpha olefin synthetic oil. According to the magnetorheological fluid, collaborative innovation is achieved in the three aspects of materials, structures and systems, comprehensive improvement of sedimentation stability, magnetic saturation strength, yield stress and redispersibility is synchronously achieved, meanwhile, the zero-field viscosity is reduced, and the magnetorheological fluid with excellent comprehensive performance is obtained. The prepared magnetorheological fluid can stand for a long time without hard block deposition, is fast in magnetic response and high in working stability, can better adapt to the actual working condition of the magnetorheological damper, and has outstanding application value.

The application provides a semi-metal compensation ferrimagnetic material, the chemical formula of the semi-metal compensation ferrimagnetic material is CrFeS2, the semi-metal compensation ferrimagnetic material has a hexagonal NiAs type crystal structure and belongs to the 194th space group, and a preparation method thereof comprises the following steps: sealing Cr powder, Fe powder and sulfur blocks and a transmission medium iodine in a vacuum quartz tube; placing the vacuum quartz tube in a heating furnace and heating at 780-920 DEG C for 4-30 days, and then quenching to a warm house. The semi-metal compensation ferrimagnetic material provided by the application has the characteristics of great perpendicular magnetic anisotropy and magnetic compensation characteristics, so that the material can realize zero-field cold exchange bias, and a unidirectional magnetic field with different sizes can control the direction of the exchange bias, and thus the material has a wide application prospect in the field of spintronics.

The invention provides a high-field and near-zero-field combined magnetic resonance system, which comprises a sample tube for placing a sample, a high-field measurement module for pre-polarization of the sample and high-field chemical shift spectrum measurement, and a near-zero-field magnetic resonance module for J coupling signal measurement of the sample in the near-zero field, the sample transmission module is used for driving a sample to move between a high field and a near-zero field and maintaining nuclear spin polarization of the sample in the moving process; the digital control and signal processing module is used for automatic control and synchronous signal acquisition of the high field measurement module and the near-zero field magnetic resonance module; the invention also provides a high field and near zero field combined magnetic resonance detection method and a measurement method. According to the invention, a high-field spectrogram and a near-zero-field spectrogram are obtained in one measurement cycle, and unified correspondence of chemical shift and J coupling is realized. Through combination of high-field pre-polarization and rapid shuttling, the signal-to-noise ratio of near-zero field measurement is improved by about one order of magnitude, and the spectral line width is significantly reduced.

This invention relates to the field of zero-field detection technology, specifically disclosing a measuring device for measuring the zero field within a tokamak device, and the tokamak device itself. It includes a magnetic probe fixing plate, within which several magnetic probes are disposed. The magnetic probe fixing plate is movably connected to a square frame, which is fixedly connected to a support frame. The support frame is movably connected to an annular support guide rail, and a limiting element is fixedly connected to the square frame. Through motor control, the zero field formed by the magnetic probe fixing plate at different circumferential positions within the tokamak device can be measured, solving the problems of fixed magnetic probe positions and high cost due to the large number of magnetic probes used. Simultaneously, the increased number of measurement points makes the measurement data more accurate. Because it can automatically measure the zero field at different circumferential positions of the device, the number of times the device needs to enter and exit the tokamak vacuum chamber and disassemble the array is reduced, ensuring the cleanliness of the vacuum chamber and reducing measurement errors and difficulty caused by human error.

A magnetometer includes a first substrate, a bare semiconductor die, a first conductive trace, a second conductive trace, a second substrate, and a planar magnetic-field coil. The first substrate is composed of a high-temperature electrically insulating material. The bare semiconductor die is affixed to the first substrate and includes a p-n junction that contains paramagnetic recombination centers. The first and second conductive traces are on the first substrate. The first conductive trace is electrically connected to an anode of the p-n junction. The second conductive trace is electrically connected to a cathode of the p-n junction. The second substrate is composed of a high-temperature electrically insulating material and is affixed to the first substrate. The planar magnetic-field coil is composed of a metal trace formed on the second substrate.

A controllable source audio frequency magnetotelluric sounding transmitting end electrode arrangement system and method belong to the technical field of electromagnetic prospecting, and particularly relate to the technical field of electromagnetic sounding electrode arrangement. The system and method solve the technical problem that the current CSAMT transmitting end electrode arrangement technology cannot simultaneously achieve the core target of "greatly reducing resistance and increasing current + zero field source distortion + high construction feasibility". The system and method comprise a main dipole unit and A-side and B-side distributed auxiliary electrode arrays. The main dipole unit is composed of A0 and B0 main transmitting electrodes. The A-side auxiliary electrode array is arranged in a direction away from the B0 along a dipole axis, the B-side auxiliary electrode array is arranged in a direction away from the A0 along the dipole axis, and the double-side arrays are completely symmetrical along the dipole center. All same-side electrodes are connected in parallel at an equal potential to a transmitter, and the transmitting current is in-phase and equal potential. The system and method only need short electrodes and artificial shallow pits for arrangement, the grounding resistance is greatly reduced, the transmitting current is steadily increased, and the ideal horizontal electric dipole field source characteristics are strictly guaranteed without field source distortion.

The invention provides high-stability magnetorheological fluid and a preparation method thereof, and belongs to the technical field of magnetorheological fluid. The magnetorheological fluid is prepared from the following raw materials in parts by mass: 50 to 65 parts of composite magnetic particles, 0.5 to 2 parts of ferroferric oxide / inorganic composite material, 30 to 40 parts of carrier liquid, 0.5 to 2 parts of surfactant and 0.5 to 2 parts of anticoagulant. The magnetorheological fluid disclosed by the invention has excellent suspension stability, is not easy to settle, is slightly layered during long-term use, can quickly float in a weak magnetic field and is quick in response, and meanwhile, the magnetorheological fluid disclosed by the invention is large in yield stress and relatively low in zero-field viscosity. Composite magnetic particles are prepared from carbonyl carbon powder and polyvinylpyrrolidone with different particle sizes, and then the composite magnetic particles are combined with a ferroferric oxide / inorganic composite material and a deep eutectic solvent, so that the magnetorheological fluid with excellent performance is prepared.