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NASA NTRS2004

Advanced Power Electronics Components

This paper will give a description and status of the Advanced Power Electronics Materials and Components Technology program being conducted by the NASA Glenn Research Center for future aerospace power applications. The focus of this research program is on the following: 1) New and/or significantly improved dielectric materials for the development of power capacitors with increased volumetric efficiency, energy density, and operating temperature. Materials being investigated include nanocrystalline and composite ceramic dielectrics and diamond-like carbon films; 2) New and/or significantly improved high frequency, high temperature, low loss soft magnetic materials for the development of transformers/inductors with increased power/energy density, electrical efficiency, and operating temperature. Materials being investigated include nanocrystalline and nanocomposite soft magnetic materials; 3) Packaged high temperature, high power density, high voltage, and low loss SiC diodes and switches. Development of high quality 4H- and 6H- SiC atomically smooth substrates to significantly improve device performance is a major emphasis of the SiC materials program; 4) Demonstration of high temperature (> 200 C) circuits using the components developed above.

Schwarze, Gene E.↗

DOE OSTI2025

Skyrmion-like Spin Textures Emerging in the Material Derived from Structural Frustration

Magnetic materials with complex spin textures present both fundamental and practical appeal. The complex patterns of magnetic moments emerging on underlying crystal lattices hold potential for robust information storage and processing, including the promise of topological quantum computing. The scope of materials that host such patterns, however, remains rather limited. Here, in this study, we report a discovery of a complex spin texture in a noncentrosymmetric material that emerges from the structural frustration at the boundary between centrosymmetric parent structures MnCoGe (the hexagonal Ni 2 In or the orthorhombic TiNiSi structure type) and MnCoAs (the TiNiSi structure type). Our findings demonstrate that such structural frustration provides a powerful handle for identifying compositional spaces where complex magnetic behavior and associated nontrivial magnetic structures are likely to emerge. Thus, the new phase MnCoGe 1/3 As 2/3 exhibits a modulated cycloidal antiferromagnetic arrangement of electron spins on a noncentrosymmetric lattice (of the hexagonal ZrNiAl type) that materializes in the space between centrosymmetric collinear ferromagnets. This work provides a pathway for discovering novel materials with exotic spin textures for next-generation spintronics and quantum technologies.

Wang, YiXu [Florida State University, Tallahassee,↗

NASA NTRS1992

Comparison of high temperature, high frequency core loss and dynamic B-H loops of a 2V-49Fe-49Co and a grain oriented 3Si-Fe alloy

The design of power magnetic components such as transformers, inductors, motors, and generators, requires specific knowledge about the magnetic and electrical characteristics of the magnetic materials used in these components. Limited experimental data exists that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency over a wide flux density range. An experimental investigation of a 2V-49-Fe-49Co (Supermendur) and a grain oriented 3 Si-Fe (Magnesil) alloy was conducted over the temperature range of 23 to 300 C and frequency range of 0.1 to 10 kHz. The effects of temperature, frequency, and maximum flux density on the core loss and dynamic B-H loops for sinusoidal voltage excitation conditions are examined for each of these materials. A comparison of the core loss of these two materials is also made over the temperature and frequency range investigated.

Wieserman, W. R.↗

NASA NTRS1992

Comparison of high temperature, high frequency core loss and dynamic B-H loops of a 2V-49Fe-49Co and a grain oriented 3Si-Fe alloy

Wieserman, W. R.↗

NASA NTRS2024

AC and DC Fault Management for Megawatt Electrified Aircraft Electrical Powertrains - Task 2: Power Quality Filtering Using Nanocrystalline Soft Magnetic Inductor

The NASA RTAPS program on AC and DC Fault Management for Megawatt Electrified Power Train is a multi-year joint project with Pratt & Whitney (P&W), Collins Aerospace (CA), and RTX Technology Research Center (RTRC). This research program focuses on the high-voltage distribution issues that present a significant technological obstacle in the adoption of Electrified Aviation Propulsion (EAP) systems. One challenge to the adoption of high-voltage distribution systems with power electronic converters is the need for filter elements to limit the generation and propagation of noise, protect the cable systems from premature aging and prevent against excessive heating within subcomponents due to high-frequency induced currents. While increased distribution voltages aide in reducing the cable mass for a fixed power system, the associated mass with the filtering elements for power electronic converter can grow with increasing distribution voltages – thereby mitigating any benefit associated with increasing the distribution system voltage. To enable high-voltage distribution systems with high system specific power densities, new magnetic materials must be developed. Therefore, the second task of the NASA RTAPS program is associated with the design and application of advanced soft magnetic components for Megawatt class electric propulsion systems, specifically the motor drive system. This report covers the collaborative work between NASA Glenn Research Center (GRC), RTRC, P&W and CA in the development of three types of magnetic components over the span of the three-year program. These critical magnetic components are the DC side EMI filter, which limits the propagation of harmful electromagnetic noise to the rise of the distribution system, and the AC side damping with the dv/dt filter, which limits the fast rise time of the power electronic converter output voltage to limit the degradation on the cable/motor insulation systems. Each of these components are investigated from component level design and are optimized at the system level with a combined modelling and testing effort. In the final experimental evaluation of the NASA developed soft magnetic material with a dv/dt filter, a commercial-off-the-shelf (COTS) magnetic core and the GRC magnetic core are optimized and loaded at 320Arms to evaluate their difference in performance. After a run time of 30 minutes in a MW-class motor driver at RTRC, the NASA GRC cores were found to not only offer a lower temperature rise of nearly 25°𝐶, but also a reduction in measured core loss of 25% (12.75W to 9.5W).

Elecrified Aircraft Propulsion↗

DOE OSTI2025

Linear magnetoconductivity as a probe of time-reversal symmetry breaking

Several optical experiments have shown that in magnetic materials, the principal axes of response tensors can rotate as an odd function of an applied magnetic field. Here we offer a microscopic explanation of this effect, and we propose a closely related dc transport phenomenon—an off-diagonal symmetric conductivity, linear and odd in a magnetic field, which we refer to as linear magnetoconductivity (LMC). Although LMC has the same functional dependence on a magnetic field as the Hall effect, its origin is fundamentally different: LMC requires time-reversal symmetry to be broken even before a magnetic field is applied, and is therefore a sensitive probe of magnetism. We demonstrate LMC in three different ways: via a tight-binding toy model, a density functional theory calculation on MnPSe3, and a semiclassical treatment. The third approach identifies two distinct mechanisms yielding LMC: momentum-dependent band magnetization and Berry curvature. Finally, we propose an experimental geometry suitable for detecting LMC, and we demonstrate its applicability using Landauer-Büttiker simulations. Our results emphasize the importance of measuring the full conductivity tensor in magnetic materials, and they introduce LMC as a new transport probe of symmetry.

Sunko, V↗

NASA NTRS1990

The magnetization process: Hysteresis

The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

Balsamel, Richard↗

NASA NTRS1970

Magnetic properties and natural remanent magnetization of lunar materials

Lunar rocks magnetic properties and natural remanent magnetization, examining pyroxene paramagnetism, ferrosilite and ilmenite antiferromagnetism and native iron ferromagnetism

Fisher, R. M.↗

NASA NTRS1976

Design of air-gapped magnetic-core inductors for superimposed direct and alternating currents

Using data on standard magnetic-material properties and standard core sizes for air-gap-type cores, an algorithm designed for a computer solution is developed which optimally determines the air-gap length and locates the quiescent point on the normal magnetization curve so as to yield an inductor design with the minimum number of turns for a given ac voltage and frequency and with a given dc bias current superimposed in the same winding. Magnetic-material data used in the design are the normal magnetization curve and a family of incremental permeability curves. A second procedure, which requires a simpler set of calculations, starts from an assigned quiescent point on the normal magnetization curve and first screens candidate core sizes for suitability, then determines the required turns and air-gap length.

Ohri, A. K.↗

DOE OSTI2024

Accurate machine-learning predictions of coercivity in high-performance permanent magnets

Increased demand for high-performance permanent magnets in the electric vehicle and wind-turbine industries has prompted the search for cost-effective alternatives. Discovering magnetic materials with the desired intrinsic and extrinsic permanent magnet properties presents a significant challenge to researchers because of issues with the global supply of rare-earth elements, material stability, and a low maximum magnetic energy product BH max . While first-principles density functional theory (DFT) predicts materials’ magnetic moments, magnetocrystalline anisotropy constants, and exchange interactions, it cannot compute extrinsic properties such as coercivity (H c ). Although it is possible to calculate H c theoretically with micromagnetic simulations, the predicted value is larger than the experiment by almost an order of magnitude due to the Brown paradox. To circumvent these issues, we employ machine-learning (ML) methods on an extensive database obtained from experiments, DFT calculations, and micromagnetic modeling. The use of a large experimental dataset enables realistic H c predictions for materials such as Ce-doped Nd 2 ⁢Fe 14 ⁢B, comparing favorably against micromagnetically simulated coercivities. Remarkably, our ML model accurately identifies uniaxial magneto-crystalline anisotropy as the primary contributor to H c . With DFT calculations, we predict the Nd-site-dependent magnetic anisotropy behavior in Nd 2 ⁢Fe 14 ⁢B, confirming that Nd 4⁢g sites mainly contribute to uniaxial magnetocrystalline anisotropy, and also calculate the Curie temperature (T c ). Finally, both calculated results are in good agreement with the experiments. The coupled experimental dataset and ML modeling with DFT input predict H c with far greater accuracy and speed than was previously possible using micromagnetic modeling. Further, we reverse engineer the grain-boundary and intergrain exchange coupling with micromagnetic simulations by employing the ML predictions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS1991

Comparison of high frequency, high temperature core loss and B-H loop characteristics of an 80 Ni-Fe crystalline alloy and two iron-based amorphous alloys

Limited experimental data exists for the specific core loss and dynamic B-H loops for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H characteristics of a nickel-iron crystalline magnetic alloy (Supermalloy) and two iron-based amorphous magnetic materials (Metglas 2605S-3A and Metglas 2605SC) over the frequency range of 1-50 kHz and temperature range of 23-300 C under sinusoidal voltage excitation. The effects of maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined. The Supermalloy and Metglass 2605S-3A and 2605SC data are used to compare the core loss of transformers with identical kVA and voltage ratings.

Wieserman, William R.↗

NASA NTRS1990

High pressure superconducting radial magnetic bearing

In a conventional radial magnetic bearing, the rotor (soft magnetic material) can only have attraction force from one of the electromagnets in the stator. The stator electromagnets consist of small copper windings with a soft magnetic material iron yoke. The maximum pressure obtainable is about 200 N/sq cm. It is shown that replacing the stator copper winding by a superconducting winding in the above configuration can increase the pressure to about 1000 N/sq cm. It is also shown that replacing the iron in the rotor by a group of superconducting windings in persistent mode and using a group of saddle coils in the stator can produce a pressure in excess of 2000 N/sq cm.

Eyssa, Y. M.↗

DOE OSTI2024

Permanent Magnet Resiliency in Jefferson Lab’s Radiation Environment: LDRD Grant Status and Plans

As the FFA@CEBAF energy upgrade study progresses, it is important to investigate the impact of radiation exposure on the permanent magnet materials to be used in the upgraded fixed field alternating gradient (FFA) arcs. To address this, Jefferson Lab has awarded a Laboratory Directed Research and Development (LDRD) grant to study the resiliency of several permanent magnet materials placed in a radiation environment similar to that in which they are expected to operate. Samples of NeFeB and SmCo are to be placed alongside appropriate dosimetry in a variety of radiation environments in the beam enclosure and experimental halls at CEBAF. The magnet degradation will be measured, and extrapolated to the higher energies expected during operations after the energy upgrade. This document will describe the current status of the LDRD study, as well as describe the upcoming plans. It will also direct the readers to other proceedings which further detail the work thus far.

Bodenstein, R.↗

DOE OSTI2025

Zero-bias conductance peaks at zero applied magnetic field due to stray fields from integrated micromagnets in hybrid nanowire quantum dots

Many recipes for realizing topological superconductivity rely on broken time-reversal symmetry, which is often attained by applying a substantial external magnetic field. Alternatively, using magnetic materials can offer advantages through low-field operation and design flexibility on the nanoscale. Mechanisms for lifting spin degeneracy include exchange coupling, spin-dependent scattering, spin injection – all requiring direct contact between the bulk or induced superconductor and a magnetic material. Here, we implement locally broken time-reversal symmetry through dipolar coupling from nearby micromagnets to superconductor-semiconductor hybrid nanowire devices. Josephson supercurrent is hysteretic due to micromagnets switching. At or around zero external magnetic field, we observe an extended presence of Andreev bound states near zero voltage bias. We also show a zero-bias peak plateau of a non-quantized value. Our findings largely reproduce earlier results where similar effects were presented in the context of topological superconductivity in a homogeneous wire, and attributed to more exotic time-reversal breaking mechanisms [Nat. Phys. 17, 43 (2020)]. In contrast, our stray field profiles are not designed to create Majorana modes, and our data are compatible with a straightforward interpretation in terms of trivial states in quantum dots. At the same time, the use of micromagnets in hybrid superconductor-semiconductor devices shows promise for future experiments on topological superconductivity.

Jiang, Luyao [Univ. of Pittsburgh, PA (United Stat↗

NASA NTRS1999

Non-Equilibrium Superconductivity and Magnetic Pair Breaking in Perovskite Half-Metallic Ferromagnet-Insulator-Superconductor (F-I-S) Heterostructures

The effect of spin-polarized quasiparticle currents on the critical current density (J-c) of cuprate superconductors is studied in perovskite F-I-S heterostructures as a function of insulator thickness and of underlying magnetic materials. A pulsed current technique is employed to minimize extraneous Joule heating on the superconductor. At temperatures near T-c, F-I-S samples with insulator thicknesses\1e2nm show precipitous decrease in J_c as current injection (I_m) is increased. In contrast, J_c in a controlled sample with a substituted non-magnetic material (N-I-S) exhibit no dependence on I_m. Similarly, a F-I-S sample with a 10 mn insulating barrier also show little J_c effect versus I_m. At low temperatures with I_m = 0, significant suppression of J-c is observed only in the thin barrier F-I-S samples, although T_c and the normal-state resistivity of all samples are comparable. These phenomena can be attributed to the Cooper pair breaking induced by externally-injected and internally-reflected spin-polarized quasiparticle currents. We estimate an order of magnitude range for the spin diffusion length of 100 nm to 100\ mum.

Fu, C.-C.↗

NASA NTRS1991

Comparison of high temperature, high frequency core loss and dynamic B-H loops of two 50 Ni-Fe crystalline alloys and an iron-based amorphous alloy

The availability of experimental data that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency is almost nonexistent. An experimental investigation was conducted over the temperature range of 23 to 300 C and frequency range of 1 to 50 kHz to determine the effects of temperature and frequency on the core loss and dynamic B-H loops of three different soft magnetic materials; and oriented grain 50Ni-50Fe alloy, a nonoriented grain 50Ni-Fe alloy, and an iron based amorphous material (Metglas 2605SC). A comparison of these materials shows that the nonoriented grain 50Ni-50Fe alloy tends to have either the lowest or next lowest core loss for all temperatures and frequencies investigated.

Wieserman, W. R.↗

NASA NTRS1991

Comparison of high temperature, high frequency core loss and dynamic B-H loops of two 50 Ni-Fe crystalline alloys and an iron-based amorphous alloy

The availability of experimental data that characterize the performance of soft magnetic materials for the combined conditions of high temperature and high frequency is almost nonexistent. An experimental investigation was conducted over the temperature range of 23 to 300 C and frequency range of 1 to 50 kHz to determine the effects of temperature and frequency on the core loss and dynamic B-H loops of three different soft magnetic materials: an oriented-grain 50Ni-50Fe alloy, a nonoriented-grain 50Ni-50Fe alloy, and an iron-based amorphous material (Metglas 2605SC). A comparison of these materials shows that the nonoriented-grain 50Ni-50Fe alloy tends to have either the lowest or the next lowest core loss for all temperatures and frequencies investigated.

Wieserman, W. R.↗

NASA NTRS1991

Development of a miniaturized, light-weight magnetic sector for a field-portable mass spectrograph

A miniaturized, lightweight magnetic sector for a focal plane mass spectrograph (Mattauch-Herzog design) has been designed and fabricated by using a new high-energy-product magnet material (Nd-B-Fe alloy) and a high permeability magnet yoke material (V-Co-Fe alloy). The magnetic sector weighs less than 10 kg, has a focal plane of 5.1 cm in length, and covers a nominal mass range of 40-240 amu. Such a magnetic sector, in conjunction with an array detector and a short microbore capillary column, is well suited for the development of a field-portable gas chromatograph-mass spectrometer instrument of high performance.

Sinha, M. P.↗