Browse Topic: Magnetic materials

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Operating Characteristics of an Automotive Adjustable-Field Permanent Magnet Motors with 3D Magnetic Paths and Asymmetric Magnet Arrangement2024-32-002704/18/2025
This paper describes a three-dimensional structure of an adjustable field magnetization permanent magnet (PM) motor and a high-power density rotor structure with asymmetric permanent magnet arrangement for both high torque and high efficiency operation in the high speed and low torque range. 3D-FEA has confirmed that it is possible to achieve both high torque density and adjustable field magnetization. Load testing using the prototype proposed motor confirmed that high motor efficiency can be achieved even during high-speed operation.
Hiyoshi, Yutaro, Doi, Kotaro, Noguchi, Toshihiko
RESEARCH OF THE EFFECTS OF INTEGRATION INTO ARMOR ON THE PERFORMANCE OF SPINTRONIC MICROWAVE DETECTORS2024-01-333411/15/2024
ABSTRACT The authors studied the effects of different types of armor on the performance of spin-torque microwave detectors (STMD). Working prototypes of novel nano-sized spintronic sensors of microwave radiation for battlefield anti-radar and wireless communications applications are being integrated into Sensor Enhanced Armor (SEA) and Multifunctional Armor (MFA) and tested in SEA-NDE Lab at TARDEC. The preliminary theoretical estimations have shown that STMD based on the spin-torque effect in magnetic tunnel junctions (MTJ), when placed in the external electromagnetic field of a microwave frequency, can work as diode detectors with the maximum theoretical sensitivity of 1000 V/W. These STNO detectors could be scaled to sub-micron size, are frequency-selective and tunable, and are tolerant to ionizing radiation. We studied the performance of a STMD in two different dynamical regimes of detector operation: in well-known traditional in-plane regime of STMD operation and in recently
Bankowski, Elena, Meitzler, Thomas, Pesys, Tomas
Measurement uncertainty and its influence on e-Drive optimization applications2024-26-009701/16/2024
This paper gives insights in the theoretical measurement uncertainty of E-Drive rotor position dependent results, like Id and Iq calculations, done by a modern propulsion power analyzer (PA). The calculation of Id and Iq is fundamental to perform control optimization and application tasks for an E-Drive system. In order to optimize the E-Drive system application towards e.g. best efficiency, best performance, or improved NVH the importance of the testing toolchain is described: a power analyzer delivering the required results, an automation system, and a Design of Experiment tool to set improved target values. Consequently, inverters applications featuring field-oriented control (FOC) with permanent magnet synchronous machines (PMSM) are updated with a chosen control strategy. For achieving a certain behavior of an E-Drive, different degrees of freedom in the Inverter Control Unit are available; Lookup tables Id and Iq represent two fundamental application labels to be considered
Platzer, Thomas, Fechter, Michael, Kammerstetter, Heribert, Kolb, Philipp
Design approach on magnetic speed reduction of bikes while turning2022-28-048011/18/2022
Turning two-wheelers (bikes) are, at times, risky and often disturbs the stability of the vehicle. The primary causes are excessive speed, severe acceleration, and over tilting. This work intends in making aid for a safer ride and improves turn ability. With the introduction of automatic speed reducers, the vehicle would be subjected to magnetic braking while making a turn. A Motion stabilizer (like Gimbals) is modeled in CATIA and fabricated using PVC material. This fabricated stabilizer is placed in the vehicle setup in between the arms which carry the magnet. Braking action is done automatically as the magnet gets closer to the rim while turning the setup. Three modes of operations such as test (i) under no load, no angle, (ii) under magnetic load at zero angles, and (iii) under magnetic load, at an angle on both lateral directions, have been tested. A spectrum analyzer has been used, which records the frequency correspondingly to the speed is calculated. The counterbalancing weight
S, Ragul
Non-destructive Evaluation of the Magnetic Quality of Electrical Steel Sheets by Magnetic Barkhausen Noise (MBN) Analysis2022-01-026903/29/2022
Soft magnetic lamination core is a major component of all electric motors, and the magnetic quality of the lamination has a significant effect on the energy efficiency of the motor. The magnetic properties of electrical steel sheets, which are important design parameters for the manufacturing of electric motors, are normally measured on cut steel strips by standard Epstein frame method, which is destructive and is not suitable for the evaluation of magnetic anisotropy. This paper presents a relatively new technology, i.e., magnetic Barkhausen noise (MBN) analysis, to evaluate the magnetic quality of electrical steel sheets. This method is featured by non-destructive, simple measurement, short measuring time, and online/offline measurements, etc. In addition, it can be readily used to estimate the magnetic anisotropy of electrical steel sheets. Non-oriented electrical steel sheets at different stages of thermomechanical processing were evaluated by MBN analysis, and the textures of the
He, Youliang
Polyetherimide for magnet wire application 2022-01-040003/29/2022
Magnet wire is composed of conducting core and thin layer of electrical insulation. Cupper (Cu) is typically used as conducting core, and various polymers such as polyamideimide, polyimide, and polyesterimide are used for electrical insulation. The role of magnet wire is involved in interchanging between electrical energy and mechanical energy for energy transformation application such as transformer, motor, generator, and many other equipment. Currently, electric vehicles (EV) industry is rapidly growing and consequential demands on related components are increasing as well. Compared to combustion engine, EV needs more electrical power with higher voltages or higher currents, which can increase probability of electrical discharge. The degradation of insulation layer can happen with the polymer bond breakage under the partial discharge electric stresses. To keep high performance under higher voltage, insulating polymer should have high heat resistances, chemical resistance, and low
Kim, Sang Hoon, Lee, Dae Ho
Fine-Tuning Alloys for High-Temperature UseTBMG-3960708/01/2021
A phenomenon related to the invar effect — which enables magnetic materials such as nickel-iron (Ni-Fe) alloys to keep from expanding with increasing temperature — has been discovered in paramagnetic, or weakly magnetized, high-temperature alloys.
Reconfigurable Electronics Based on Multiferroics and Nanomagnetism21AERP02_0902/01/2021
Research could lead to the development of new materials with large magnetoelectric (ME) coupling for next-generation multifunctional devices, including, multi-state (neuromorphic-like) circuits and memories, and E-field tunable microwave resonators for secure communications. Air Force Research Laboratory, Arlington, Virginia Multifunctional magnetoelectric materials with high exchange represent a missing “holy grail” of materials physics. To combine polarization and magnetization in the same solid is nothing short of actually controlling the fundamental nature of electromagnetism in matter. Although magnetoelectricity (ME) is an intrinsic phenomenon in some natural materials at low temperature, such single-phase materials suffer from an extremely weak ME exchange. In contrast, composites consisting of magnetostrictive and piezoelectric phases can feature dramatically larger ME coefficients. This proposed program focuses on achieving the disruptive potential of emerging multifunctional
Reconfigurable Electronics Based on Multiferroics and NanomagnetismTBMG-3853902/01/2021
Multifunctional magnetoelectric materials with high exchange represent a missing “holy grail” of materials physics. To combine polarization and magnetization in the same solid is nothing short of actually controlling the fundamental nature of electromagnetism in matter. Although magneto-electricity (ME) is an intrinsic phenomenon in some natural materials at low temperature, such single-phase materials suffer from an extremely weak ME exchange.
Miniscule Robots of Metal and PlasticTBMG-3851502/01/2021
Researchers have been pursuing the development of robots so tiny that they can maneuver through blood vessels and deliver medications to certain points in the body. Now, scientists have succeeded in building such micromachines out of metal and plastic in which these two materials are interlocked as closely as links in a chain. This is possible thanks to a new manufacturing technique they have devised.
Chemical Identification by Magneto-Elastic Sensing (ChIMES)TBMG-3848302/01/2021
A low-cost sensor technology, called Chemical Identification by Magneto-Elastic Sensing (ChIMES), uses target response materials (TRMs) as actuators in magneto-elastic (M-E) sensors (Figure 1).
Sensing Magnetic FieldsTBMG-3851102/01/2021
Innovators at NASA Armstrong developed an optical waveguide fiber Bragg grating (FBG) that is sensitive to an external magnetic field. The technology allows direct coupling of the external field to the electromagnetic (EM) wave propagating in the fiber, bypassing the need to first measure strain.
Design of New Piezoelectric Composites Using Nanocellulose20AERP12_1012/01/2020
Using cellulose crystals as building blocks for the design and development of new low-density functional polymer composites. Air Force Research Laboratory, Arlington, Virginia This research project focused on cellulose crystals as building blocks for the design and development of new low-density functional polymer composites. Although the piezoelectricity of cellulose has been predicted from its noncentrosymmetric crystal structure, it has not been measured accurately, nor has cellulose been properly exploited as a piezoelectric material. If it is proven, it could enable novel low-density electroactive materials capable of surpassing the performance of the best synthetic piezoelectric polymer such as polyvinylidene difluoride (PVDF). To fulfill this objective, a systematic study was required to judiciously manipulate dipoles of individual cellulose nanocrystals to produce polar ordering at the macroscale and accurately characterize the nano-to-mesoscale structural ordering and
Soft Magnetic Nanocomposite for High-Temperature ApplicationsTBMG-3798011/01/2020
Commercial soft magnetic cores used in power electronics are limited by core loss and decreased ferromagnetism at high temperatures. Extending functional performance to high temperatures enables increased power density in electric systems with fixed power output and elevated operating temperature.
Tiny, Magnetically Powered Neural StimulatorTBMG-3800811/01/2020
Neuroengineers have created a tiny surgical implant that can electrically stimulate the brain and nervous system without using a battery or wired power supply. The device draws its power from magnetic energy and is about the size of a grain of rice. It is the first magnetically powered neural stimulator that produces the same kind of high-frequency signals as clinically approved, battery-powered implants that are used to treat epilepsy, Parkinson’s disease, chronic pain, and other conditions.
“One-Way” Electronic DevicesTBMG-3779910/01/2020
Waves — whether they are light waves, sound waves, or any other kind — travel in the same manner in forward and reverse directions. This is known as the principle of reciprocity. If waves could be routed in one direction only — breaking reciprocity — many applications could be transformed by enabling “one-way” components such as circulators and isolators that enable two-way communication, which could double the data capacity of today's wireless networks. These components are essential to quantum computers that read a qubit without disturbing it. They are also critical to radar systems in self-driving cars or those used by the military.
“Racetrack Memory” Digital Data StorageTBMG-3747208/01/2020
A team of scientists has created racetrack memory, a new type of enhanced digital data storage. Racetrack memory, which reconfigures magnetic fields, could supplant current methods of mass data storage, such as flash memory and disk drives, due to its improved density of information storage, faster operation, and lower energy use. The team’s focus was on a skyrmion racetrack memory — an undeveloped type of memory that reverses the processes of existing storage.
Room-Temperature Magnon SwitchTBMG-3744908/01/2020
Researchers have demonstrated a potentially new way to make switches inside a computer’s processing chips, enabling them to use less energy and radiate less heat. The practical technique controls magnons, which are essentially waves that travel through magnetic materials and can carry information. To use magnons for information processing requires a switching mechanism that can control the transmission of a magnon signal through the device.
Magnetic Force Manages PainTBMG-3746408/01/2020
Mainstream modern medicine centers on using pharmaceuticals to make chemical or molecular changes inside the body to treat disease; however, recent breakthroughs in the control of forces at small scales have opened up a new treatment idea: using physical force to kickstart helpful changes inside cells. This idea is referred to as “mechanoceuticals.”
Active Material Created Out of Microscopic Spinning ParticlesTBMG-3746208/01/2020
At the atomic level, a glass of water and a spoonful of crystalline salt couldn’t be more different. Water atoms move around freely and randomly, while salt crystals are locked in place in a lattice. But some new materials show an intriguing propensity to sometimes behave like water and sometimes like salt, giving them interesting transport properties and holding potential promise for applications like mixing and delivery in the pharmaceutical industry.
Solenoid Valve Health MonitorTBMG-3700506/01/2020
The Solenoid Valve Health Monitor System (SVHMS) was developed to remotely monitor the health of solenoid valves, lowering operational costs and increasing reliability by predicting valve failures before they occur. The system measures and analyzes steady state and transient components of the magnetic field and indirectly, the electric current in a solenoid valve during normal operation. It enables continuous monitoring of the integrity and operational status of solenoid valves without the need for interrupting their operation to conduct frequent inspections.
Graphene Device with Superconducting, Insulating, and Magnetic PropertiesTBMG-3703206/01/2020
Thinner than a single strand of DNA yet 200 times stronger than steel, graphene is an excellent conductor of electricity and heat and it can conform to any number of shapes, from an ultrathin 2D sheet to an electronic circuit.
Improving Data Speeds with Laser-Activated MagnetsTBMG-3702506/01/2020
A new magnetic material could boost the storage capacity and processing speed of hard drives used in cloud-based servers. This could enable users of cloud data systems to load large files in seconds instead of minutes.
Alleviating the Magnetic Effects on Magnetometers Using Vehicle Kinematics for Yaw Estimation for Autonomous Ground Vehicles2020-01-102504/14/2020
Autonomous vehicle operation is dependent upon accurate position estimation and thus a major concern of implementing the autonomous navigation is obtaining robust and accurate data from sensors. This is especially true, in case of Inertial Measurement Unit (IMU) sensor data. The IMU consists of a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer. The IMU provides vehicle orientation in 3D space in terms of yaw, roll and pitch. Out of which, yaw is a major parameter to control the ground vehicle’s lateral position during navigation. The accelerometer is responsible for attitude (roll-pitch) estimates and magnetometer is responsible for yaw estimates. However, the magnetometer is prone to environmental magnetic disturbances which induce errors in the measurement. The present work focuses on alleviating magnetic disturbances for ground vehicles by fusing the vehicle kinematics information with IMU senor in an Extended Kalman filter (EKF) with the vehicle orientation represented
Dudekula, Ahammad Basha, Naber, Jeffrey D.
Current control method for asymmetric dual three-phase Permanent Magnet Synchronous Motor2020-01-047004/14/2020
Based on the vector space decomposition (VSD) transformation, the phase currents of the asymmetric dual three phase permanent magnet synchronous motor (ADT-PMSM) can be mapped into three orthogonal subspaces, i.e., α–β subspace, x-y subspace and O1-O2 subspace. The mechanical energy conversion takes place in the α–β subspace, while in the x-y and O1-O2 subspaces only losses are produced. With neutral points being isolated, O1-O2 subspace can be omitted. So the vector control algorithm can control the α–β and x-y subspaces separately to realize the four dimensional current control. In the α–β subspace, deviation decoupling control method is employed to realize the mechanical energy conversion, which is robust to the motor parameters. In order to reduce the 5th and 7th harmonic currents caused by the inverter nonlinearity and some other factors, a resonant controller is adopted based on a new synchronous rotating coordinate transformation matrix to implement the current closed loop
Wu, Zhihong, Gu, Weisong, Zhu, Yuan, Lu, Ke
Fabrication and Electrical Characterization of Correlated Oxide Field Effect Switching Devices for High Speed ElectronicsTBMG-3660604/01/2020
Metal insulator transitions (MITs) in oxides are an intriguing problem from both a fundamental materials physics and an applied technology perspective. Though the precise roles of electron correlations and lattice distortions on the phase transition remains an active area of research, many recent theoretical studies have suggested intimate interplay among the orbital splitting/polarization, correlation effects, and Peierls dimerization in the 3d1 system. Occupied states have been probed by x ray photoelectron spectroscopy (XPS), and a rough structure of unoccupied 3d-like states have been deduced by O K-edge x-ray absorption measurements. NbO2, a 4d1 system, like VO2 crystallizes in a distorted rutile type structure with Nb dimers and undergoes a temperature induced MIT, albeit at a considerably higher temperature of ~1083 K. It is commonly accepted that because 4d orbital valence states are more dispersed in both space and energy, Mott physics is less important in 4d transition metal
Magnetic Shield Using Proximity Coupled, Spatially Varying Superconducting Order ParametersTBMG-3616503/01/2020
NASA Goddard Space Flight Center has developed a magnetic shielding design that features simplicity, ease of use, reproducibility, longevity, and scalability. It does not require activation, monitoring, or wiring. The invention uses the superconducting “proximity effect” and/or the “inverse proximity effect” to form a spatially varying order parameter. When designed to expel magnetic flux from a region of space, the proximity effect(s) are used in concert to make the superconducting order parameter strongly superconducting in the center and more weakly superconducting toward the perimeter. The shield is then passively cooled through the superconducting transition temperature.
Intelligent MicrorobotsTBMG-3600402/01/2020
Researchers have developed a microrobot that measures a few micrometers across and resembles a paper bird made with origami. But unlike a paper structure, the robot moves without a visible force. It flaps its wings or bends its neck and retracts its head via magnetism.
Composite Electrical ConnectorsAIR4567B (Current)01/21/2020
This SAE Aerospace Information Report (AIR) establishes guidelines for evaluating composite electrical connectors and accessories.
AE-8C1 Connectors Committee
Magneto-Optic Biosensor Using Bio-Functionalized Magnetic NanoparticlesTBMG-3582701/01/2020
Magnetic nanoparticles are leading to the development of more sensitive, rapid, and cost-effective biological sensors. These sensors can be used for a variety of applications including the detection of medical conditions and bioterrorist threats.
Magnetic Metamaterial Could Improve MRIsTBMG-3577201/01/2020
Researchers have developed a low-cost, “intelligent” metamaterial that could revolutionize magnetic resonance imaging (MRI), making the entire MRI process faster, safer, and more accessible to patients around the world.
3D-Printed Soft Mesh RobotsTBMG-3515509/01/2019
Researchers have created 3D-printed flexible mesh structures that can be controlled with applied magnetic fields while floating on water. The structures can grab small objects and carry water droplets, giving them the potential to be useful as soft robots that mimic creatures living on water surfaces or that can serve as tissue scaffolds for cell cultures.
A Novel Kind of Proportional Electromagnetic Dynamic Vibration Absorber2019-01-158606/05/2019
A new proportional electromagnetic dynamic vibration absorber (EDVA) is proposed for control of engine vibration during idling. The device consists of an electromagnetic actuator attached to the primary structure through elastic element, where the driving force pair is implemented between the reaction-mass and the primary structure. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. A methodology is proposed to achieve magnetic force proportional to square of current and consistent with the disturbance frequency. The proportional EDVA is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies. The effectiveness of the hybrid
FU, Tao
Structural Vibration and Acoustic Analysis of a 3-Phase AC Induction Motor2019-01-145806/05/2019
This paper aims to study the NVH and acoustic performance of a 3-phase AC induction motor in order to develop an approach to reduce the magnetic component of noise from an electric motor in an electric vehicle (EV). The final goal of this project is to reduce the magnetic component of sound from the motor by making modifications to the end bracket of the motor housing. EVs are being considered the future of mobility mainly due to the fact that they are environment-friendly. As many companies are already investing in this technology, electric drives are set to become extremely popular in the years to come. The heart of an EV is its motor. Modern electric vehicles are quiet, furthermore with the lack of an IC engine to mask most sounds from other components, the sound from the electric motor and other auxiliary parts become more prominent. The primary source of electromagnetic noise in a motor arises from magnetic flux variations in the air gap which interfere with the resonant
Krishnasarma, Anand, Taylor, Allan, Baqersad, Javad, Poozesh, Peyman
Improved Directed Flux MotorTBMG-3461706/01/2019
Electromagnetic motors typically convert electrical energy into rotational mechanical energy and are employed across a wide array of applications. While motors represent relatively mature technology, practitioners continue to seek ways to enhance motor operation including a decrease in cost, drop in size/weight, reduction in power consumption, increase in reliability, and enhanced degrees of freedom (i.e., the number of ways a machine can move within three-dimensional space).
Algorithm Predicts How Electromagnetic Waves Interact with Materials at the Smallest ScalesTBMG-3461406/01/2019
Magnetic materials can attract or repel each other based on their polar orientation — positive and negative ends attract each other, while two positives or two negatives repel. When an electromagnetic signal like a radio wave passes through such materials, a magnetic material acts like a gatekeeper, letting in the signals that are desired but keeping out others. They can also amplify the signal or dampen the speed and strength of the signals.
Singlet-Based Magnet for Enhanced Data StorageTBMG-3440405/01/2019
Anew type of magnet — called a singlet-based magnet — was discovered that differs from conventional magnets in which small magnetic constituents align with one another to create a strong magnetic field. By contrast, the singlet-based magnet has fields that pop in and out of existence, resulting in an unstable force, but one that potentially has more flexibility than conventional counterparts.
Rhombohedron Epitaxial Growth with Molten Target Sputtering (MTS) at 500 °C Substrate TemperatureTBMG-3438005/01/2019
This invention applies to the field of sputtering, depositing SiGe thin films on sapphire substrates. It is a method of modifying the film growth front, enabling epitaxially grown heterostructure devices at lower temperatures and with higher purity, avoiding the conventional time required (2 hours) and high-energy-consumption thermal soaking at a high temperature (800 °C.) Less than 500 °C is enough to grow the single-crystal Si1-xGex (x=0.85) film because much higher-kinetic-energy molecules reach the substrate.
Failsafe Linear Magnetic BrakesTBMG-3411304/01/2019
Linear permanent magnet brakes, also known as eddy current brakes, are a failsafe, power-free deceleration system that is used in conjunction with a metal reaction plate. Ceramic or rare earth magnets are bonded to a steel back iron plate; no input power is required.
Ferrofluid Technology Becomes a Magnet for Pioneering ArtistsTBMG-3394103/01/2019
Spinoff is NASA's annual publication featuring successfully commercialized NASA technology. This commercialization has contributed to the development of products and services in the fields of health and medicine, consumer goods, transportation, public safety, computer technology, and environmental resources.
Water Conditioning Agents for Aqueous Magnetic Particle InspectionAS4792B (Current)02/18/2019
This SAE Aerospace Standard (AS) covers water conditioning agents used to facilitate aqueous wet-method magnetic particle inspection.
AMS K Non Destructive Methods and Processes Committee
Materials Move in Response to LightTBMG-3359001/01/2019
In biology, there are many examples where light induces movement or change — think of flowers and leaves turning toward sunlight. Magnetic elastomeric composites were developed that move in different ways when exposed to light, raising the possibility that these materials could enable a wide range of products that perform simple to complex movements, from tiny engines and valves, to solar arrays that bend toward the sunlight. These simple movements could be combined into more complex motion like crawling, walking, or swimming, and can be triggered and controlled wirelessly using light.
Reusable Breakaway Mounting DeviceTBMG-3341312/01/2018
Breakaway devices are used to mount objects to systems or structures (for example, cars, drones, helmets, buildings) and prevent damage when the objects fall away from the system. Unfortunately, even in ideal scenarios, many of these devices have limitations. Breakaway bolts and shear pins have the complication of breaking and becoming unusable thereafter. Reset-table mounting devices such as hook-and-loop fasteners, reusable adhesives, or rubber mounting devices do not provide proper stability in certain applications. Electromagnetic and electromechanical-based devices can be quite large and expensive, and require a power source.
Dynamic Optical Grating Device for Modulating LightTBMG-3339912/01/2018
NASA Langley Research Center has developed a novel optical grating device that dynamically modulates light and is capable of controlling the spectral properties and propagation of light without any moving mechanical components.
Using Sound Waves to Produce Optical IsolatorsTBMG-3340512/01/2018
There are challenges involved when using magnetically responsive materials to achieve the one-way flow of light in a photonic chip, including the ability to place compact magnets on a chip. In addition, the necessary materials are not yet available in photonics foundries, creating the need for a better approach that uses only conventional materials and avoids magnetic fields.
Inorganic Compound for Use in Quantum ComputingTBMG-3323211/01/2018
Quantum computers will be able to solve problems well beyond the reach of existing computers while working much faster and consuming vastly less energy. An inorganic compound was developed that adopts a crystal structure capable of sustaining a new state of matter known as quantum spin liquid — an important advance toward quantum computing.
Fundamental Aspects of Single Molecule and Zeptomole ElectroanalysisTBMG-3302710/01/2018
The objective of this research program was to provide the fundamental understanding required for using the principles of electroanalytical chemistry to detect target molecules at very low concentration, including single molecules, with high specificity, simplicity, and low power.
Integrated Magneto-Optical Devices for On-Chip Photonic SystemsTBMG-3289909/01/2018
The magneto-optical (MO) oxide layer consists of (Bi,Y)3Fe5O12 or BiYIG, bismuth garnet. This material was selected because it has a better figure of merit than the CeYIG previously used, especially at lower wavelengths (1310 nm vs. 1550 nm). A top-down deposition process was developed in which BiYIG/YIG stacks are grown on the Si waveguide with YIG on top. The stack is annealed at 800°C/5 min to crystallize both layers, with the YIG templating the BiYIG leading to garnet phases rather than other oxides, and the BiYIG is directly on the Si waveguide. Initial attempts led to a film with Bi oxide phases, because the Bi was in excess and could not escape during the anneal as occurs in Si/YIG/BiYIG stacks. Hence the composition was adjusted to include slightly more Fe, which yielded films with only garnet peaks.
High-Speed Reluctance Machine DesignTBMG-3246408/01/2018
Silphenix GmbH is an engineering and consulting firm in Switzerland specializing in high-speed electrical machines, magnetic bearings, and electromagnetic field analysis. One project focus is compact high-speed flywheel systems for day storage of solar photovoltaic energy on the order of 0.5 to 5 KWh usable energy. An important constraint for energy day storage is extremely low loss per day (e.g. 1% per hour). This means that the idling losses have to be less than 5 W and 50 W for 0.5-kWh and 5-kWh units, respectively. Minimizing the idling losses requires not only operation in a vacuum environment, but also low bearing losses (magnetic bearings), low eddy current losses (reluctance machine), and low drag losses (cylindrical rotor surface).
Advances in Spintronic DevicesTBMG-3250308/01/2018
Spintronic devices promise to solve major problems in today's computers, which use massive amounts of electricity to generate heat. This requires expending even more energy for cooling. By contrast, spintronic devices generate little heat and use relatively minuscule amounts of electricity. Spintronic computers would require no energy to maintain data in memory. They would also start instantly and have the potential to be far more powerful than today's computers.
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