8 results about "Ferromagnetic resonance" patented technology

Described herein are methods and apparatuses to provide accurate measurement of relatively small magnetic fields under ambient conditions while being worn on an ambulatory subject. These methods and apparatuses may allow accurate and reliable detection of biomagnetic fields from organs such as the brain, heart, and muscles, using a magnetometer, and in particular, using an Acoustically Driven Ferromagnetic Resonance (ADFMR) sensor. These methods and apparatuses may incorporate one or more of: a synthetic gradiometer, flexible and / or thin-film / foil shielding, and / or denoising.

The patent discloses a high-dielectric YIG ferrite material and a preparation method thereof, and belongs to the technical field of microwave ferrite materials 1.65‑x‑y Bi 1.35 Ca x+ y Zr x Sn y Fe 5‑x‑y O 12 , wherein x=0.25-0.65, and y=0-0.5.The garnet-type microwave ferrite material has high dielectric constant and medium power characteristics, and has excellent electromagnetic performance; the relative dielectric constant epsilon is about 27, the dielectric loss tan epsilon is less than or equal to 8*10 ‑4 , the spin wave line width Delta Hk is greater than or equal to 9 Oe, the ferromagnetic resonance line width Delta H is less than or equal to 105 Oe, and 4pi Ms is greater than or equal to 1900 Gs; the garnet-type microwave ferrite material can effectively reduce the design size of a microwave circulator device and meet the miniaturization requirement.

The application belongs to the technical field of generator manufacturing, and particularly relates to a resonant generator with adjustable inductance. The saturated inductance method is applied to install a stator permanent magnet on the yoke or the slot bottom of a stator, the magnetic field of the permanent magnet passes through the pole teeth and pole shoes to form a magnetic circuit, when the rotor rotates, the magnetic field of the rotor with cross magnetic poles is continuously and alternately attracted and repelled with the magnetic field of the pole shoes and pole teeth, the magnetic flux of the pole teeth is automatically, periodically and cyclically changed, thereby the inductance of the coil with the pole teeth as a magnetic core is automatically, periodically and cyclically changed, the mutual inductance resonance and coupling resonance of the coil are generated, and the ferromagnetic resonance is automatically excited. Compared with the prior art, the application has the beneficial effects that the inductance of the coil is automatically and periodically adjusted by the saturated inductance method, the mutual inductance resonance and coupling resonance of the coil are generated, the ferromagnetic resonance is automatically excited, the generator operates in the ferromagnetic resonance state, thereby the rotational magnetic resistance of the rotor is reduced, the magnetic force of the permanent magnet is led out, and the efficiency of the generator is greatly improved.

The application relates to the technical field of spin electronic devices, and discloses a spin electronic device for visible light interface magnetic regulation, a preparation method of the spin electronic device and electronic equipment. The spin electronic device comprises a substrate, a bottom electrode located above the substrate, a magnetic layer located above the bottom electrode, which can change an in-plane ferromagnetic resonance field of the magnetic layer under the action of an exciton, the magnetic layer is an aluminum-doped cobalt alloy, an active layer located above the magnetic layer, which can generate an exciton under the action of visible light, and a top electrode located above the active layer. Through the synergistic effect of the magnetic layer and the active layer, the in-plane ferromagnetic resonance field of the visible light interface can be regulated, the injection efficiency of photo-generated electrons into the magnetic layer is improved, the regulation range of the light-controlled magnetism is expanded, and the spin electronic device has the beneficial effects of simple structure and easy realization.

This invention discloses a high-saturation magnetization, low-loss yttrium iron garnet ferrite material and its preparation method. The aim is to address the shortcomings of existing YIG ferrite materials, which have a saturation magnetization of approximately 1750 Gs, making it difficult to meet the diverse requirements of high-frequency microwave devices for wide bandwidth and low loss performance. Furthermore, simply increasing saturation magnetization through ion substitution often results in increased magnetic loss and broadened ferromagnetic resonance linewidth. This invention proposes a high-saturation magnetization, low-loss yttrium iron garnet ferrite material and its preparation method. This invention achieves a relative permittivity ε through Sr-Zr ion synergistic substitution. r The ferromagnetic resonance linewidth ΔH is 90~105 Oe, and the saturation magnetization is 4π M. s A high-saturation magnetization and low-loss yttrium iron garnet ferrite material with a magnetization range of 1800~1900 Gs has been developed, achieving synergistic optimization of high saturation magnetization and low loss, and providing a material basis for the expanded application of devices such as microwave circulators and isolators.

This invention discloses an in-situ preparation method for thin films using strong magnetic fields to control the orientation of organic molecules, as well as the prepared thin films and their applications, belonging to the field of organic semiconductor thin film technology. The preparation method includes the following steps: heating rubrene powder in a vacuum and magnetic field environment to evaporate and deposit it onto an upper substrate, thus obtaining a rubrene thin film. This in-situ preparation method for thin films using strong magnetic fields to control the orientation of organic molecules couples a high-vacuum in-situ preparation system with a superconducting strong magnetic field system. The aim is to overcome molecular thermal fluctuations at a pure gas-solid phase transition interface without solvent interference, thereby achieving precise control of the spatial orientation of weakly magnetic organic molecules. The orientation-controlled organic thin films prepared by the strong magnetic field significantly reduce the ferromagnetic resonance linewidth (Δ). H This increases its charge current density. J c,norm Therefore, the thin film after orientation control has a higher spin-charge conversion efficiency.

This invention provides a time-resolved ferromagnetic resonance measurement system, comprising a laser (for simultaneously outputting pulsed laser light and a synchrotron microwave synchronized with the pulsed laser), an optical path system, a sample module, a magnetic field module, a microwave modulation module, a photodetector, a signal extraction module, and a control unit. A delay module is configured to achieve controllable adjustment of the relative phase between the synchrotron microwave and the femtosecond probe light. The microwave modulation module modulates the synchrotron microwave and applies it to the sample. The photodetector converts the transmitted light signal into an electrical signal. The signal extraction module extracts the signal intensity and the relative phase between the modulated microwave and the pulsed laser. The control unit inverts the ferromagnetic resonance measurement parameters based on the above information. By sharing an optical clock with the same laser and combining delayed phase scanning, this system can reconstruct the time-domain magnetic moment response on the picosecond to nanosecond scale, directly obtaining the amplitude and phase of the magnetic moment in the transmission direction.

An acoustically driven ferromagnetic resonance (ADFMR) sensor configured to detect a magnetic field, the sensor including a piezoelectric substrate, an acoustic drive comprising a first acoustic transducer on the piezoelectric substrate, a second acoustic transducer on the piezoelectric substrate, a detection circuit coupled to the second acoustic transducer, and a magnetostrictive ferromagnet on the piezoelectric substrate between the first acoustic transducer and the second acoustic transducer; wherein the acoustic drive is configured to generate an acoustic wave to bias the magnetostrictive ferromagnet such that ferromagnetic resonance related absorption of the magnetostrictive ferromagnet is greater than 10%, and wherein the detection circuit is configured to detect a magnetic field experienced at the magnetostrictive ferromagnet by measuring at least one of a magnetic absorption and phase of the acoustic wave received by the second acoustic transducer.