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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Design and Prototyping of a Novel Toroidal Magnet System for MOLLER Experiment at Jefferson Lab

The Thomas Jefferson National Accelerator Facility (JLab) has designed a unique spectrometer system to measure the weak interaction between electrons. The experiment— Measurement of Lepton-Lepton Electroweak Reaction (MOLLER)—requires leveraging the recent 12 GeV electron beam upgrade and will run in JLab for three years. Focusing the signal for the MOLLER experiment requires five water-cooled toroidal magnets, each with unique geometry and with 7-fold symmetry. The five magnets operate in a vacuum and provide the magnetic field required to separate the incident beam electrons scattered from the target electrons (Møller scattering) and protons (elastic e-p scattering) in a liquid hydrogen target. The conceptual design was developed by the MOLLER Collaboration and was given to JLab in the form of amp turns and physical location, with additional physics requirements. This article presents prototyping of the coils and magnet support system and discusses the lessons learned during the process along with the plans for full magnet testing and installation. The JLab Magnet Group along with the MOLLER Collaboration developed the specification document that includes keep out zones to design the set of magnets. JLab contracted the design of the first toroid magnet (TM0) of the magnet system to Massachusetts Institute of Technology. The other four toroid magnets (TM1 through TM4) have been designed by JLab and are in the process of fabrication and assembly. Prototype coils of TM1-TM4 were fabricated by Everson-Tesla Incorporated, PA (USA). Finally, this article presents the unique challenges of the design, alignment, high current density, operating range, high radiation dose, and vacuum environment.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

HTS Accelerator Magnets Conceptual Design for Future Lepton Colliders

There is an interest in designing superconducting magnet systems for future lepton circular colliders. This application requires many low-field iron-dominated dipole and quadrupole magnets. Conventional room-temperature magnets are often used because of their low field, low total current, and low power losses. However, high electricity bills for large accelerators drive magnet design to superconductivity. High-temperature superconducting (HTS) magnets can substantially reduce energy losses in magnet systems. The present study investigated the conceptual design of HTS dipole and quadrupole magnets operating in persistent current mode. Energy is transferred into the magnet from an external detachable power source. A continuously circulating current generates a stable magnetic field. The iron-dominated magnet system concept was investigated using OPERA3D code, and the results confirmed the proposed approach’s validity.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Study of Conduction-Cooled Superconducting Quadrupole Magnets Combined with Dipole Correctors for the ILC Main Linac

A superconducting rf (SRF) cryomodule for International Linear Collider(ILC) Main Linac equips focus/steering magnets. The magnets are "superferric" magnets with four superconducting (SC) race track coils conductively cooled from the cryomodule LHe supply pipe. The quadrupole field gradient and dipole field are 40 T/m and 0.1 T, respectively. The magnet length and iron-pole radius are 1 m and 0.045 m, respectively. It is known that dark current is generated at SRF cavities and accelerated through the following linac string. The dark current reaches and heats the SC magnets. It is estimated that the power deposition in the magnet may reach more than a few watts and temperature of the SC coils may locally reach to critical temperature of NbTi. It is important to make the magnet not reach quench with sufficient conduction cooling. We aim to realize the SC magnet which can stably operate under such condition. We plan to develop test coils made of three types of SC materials, NbTi, Nb₃Sn, and MgB₂ and study thermal characteristics and stability . We will develop a short model magnet, based on the test coil results. Here, we will present the magnet design study and the R&D plan.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Magnetic contributions to corundum-eskolaite and corundum-hematite phase equilibria: A DFT cluster expansion study

Magnetic contributions have the potential to significantly influence predicted phase stability within alloy and mineral mixing phase diagrams, yet have been historically challenging to incorporate due to a significant increase to phase space sampling. Here, in this work, we employ a computational protocol that includes spin orientation as an additional configurational component within multi-component cluster expansions between magnetic and non-magnetic metal oxide alloys [calculated using density functional theory (DFT) and the generalized gradient approximation]. This approach was used to determine the effect of magnetic contributions to corundum-eskolaite and corundum-hematite phase equilibria from first principles. Two-component cluster expansions of the magnetic components of eskolaite and hematite were first performed showing the ability of this method to properly calculate their respective magnetic properties. Two-component cluster expansions were then performed for non-magnetic Al(III) and ferromagnetic Cr(III) and Fe(III), and phase diagrams were calculated for later comparison. Finally, a non-magnetic Al(III) and “up” and “down” magnetic configurations for anti-ferromagnetic Cr(III) and Fe(III) were performed. Magnetic contributions to the calculated phase diagram for the corundumeskolaite system were shown to be inconsequential but are vital for accurate determination of the corundum-hematite solvus.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Dual Phase Soft Magnetic Laminates for Low-cost, Non/Reduced-Rare-Earth Containing Electrical Machines

To accelerate the mass market adoption of electric drive vehicles, the key technology barriers in electric motors are (1) magnet cost and rare-earth element price volatility; (2) non-rare-earth electric motor performance; and (3) materials property optimization. The goal of this project was to address these barriers by advancing a unique and innovative dual phase soft magnetic material technology and demonstrating the material in a 30-kW synchronous reluctance motor without using any permanent magnet for electric vehicles. Dual phase magnetic materials offer the electric motor designer the ability to locally control the magnetic saturation level in a motor laminate, while at the same time enhancing the mechanical strength of the laminate material, resulting in an enhancement in motor performance and efficiency. Scalable dual phase soft magnetic laminates manufacturing technologies were developed in collaboration with multiple US manufacturers. 1000 lbs of alloy sheet with a thickness of 0.25mm and width of 280 mm was manufactured within the specifications. Batch sizes of up to 240 laminates per run were produced from the alloy sheet. Two prototype motors with dual phase soft magnetic laminates were designed, built, and tested. The major goal of building the subscale prototype as a pathway to develop scalable manufacturing technologies for the dual phase soft magnetic laminates was met. The additional goal of building and testing the subscale prototype in order to validate the calculated performance with the tested motor performance was also met. For the full-scale 30kW continuous power synchronous reluctance motor prototype, the tested performance met the targets in terms of continuous power at the operating speeds up to 8000 rpm. Post-test studies were conducted and the root causes for the discrepancy between the predicted and tested peak power, continuous power at high speed range, and efficiency were identified. Further modeling study showed that the dual phase rotor machine has a 27% higher torque to active weight ratio than an equivalent performance silicon steel rotor machine. Application space and multiple discussions with traction motor and electric vehicle manufacturers for commercialization of the dual phase soft magnetic material technology were identified and conducted. An initial cost model was established based on the developed manufacturing technologies with the US manufacturers. Future paths for further cost reduction were identified, including increasing the market volume by broadening the applications of the dual phase soft magnetic laminate technology for electric machines in other energy sections such as oil & gas, heating, ventilation, and air conditioning (HVAC), and power generation.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2020

Magnetic Navigation for GPS-Denied Airborne Applications

Most current flight systems are dependent on GPS for navigation. Recently, however, navigation in GPS-denied environments has become an area of intensive research. Additional navigation sensor data can be obtained from visual observations (stars or terrain), inertial measurement units, radar, measurements of the local magnetic field, or perhaps even gravity. Absolute and relative positioning via magnetic field measurements have been shown to be viable in many applications including ground navigation, low altitude aircraft flight, and spaceflight. There is greater variability in the magnetic field over shorter distances when flying at low altitude and in ground applications, leading to more accurate positioning. However, ground-based magnetic navigation is often heavily influenced by man-made structures, especially in urban environments. This is not the case for airborne magnetic navigation since the influence of buildings, roads, etc. is negligible for typical aircraft altitudes. For absolute magnetic navigation, the positioning accuracy decreases as altitude increases for a given vehicle velocity, but the observed time variability in the field can be reclaimed by traveling faster through the field. Thus, navigation accuracy becomes a balance of speed and altitude since the higher altitude can be counterbalanced by higher velocity. To understand these effects quantitatively, we explored various techniques to aid a simulated inertial measurement unit with magnetic information. Using a technique known as two-dimensional magnetic map matching, we simulated the performance of airborne magnetic navigation at fixed speed while varying the altitude, flight direction, magnetometer data collection time, reference magnetic map bias error, and type of trajectory (over land or over ocean).

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Acceptance Testing of the Scorpius Sweep Magnet

A beam-dump magnet for Scorpius has been defined by LANL and designed and built by Radiabeam Technologies. Initial verification of the Radiabeam design used a magnetic field model provided by Radiabeam and analyzed by LANL tools during September 2021. Simulations indicated that the design was sufficient to meet deflection requirements to protect sensitive equipment in the case of a failed target. In January 2022, the magnet was fabricated and Radiabeam conducted measurements of the magnetic field as a function of position. The measurements deviate somewhat from the simulation. In particular, the peak magnetic field is 10-15% smaller in magnitude than expected from simulation. This note compares the magnetic field measurements to simulation and to measurements of the existing DARHT magnet, which was designed for the same purpose. We show a comparison of the measured beam deflection performance between Scorpius and DARHT and show updated results of LANL’s electron beam tracking code using the Scorpius measurements. Using field measurements we find that the DARHT magnet will deflect a 19.6 MeV electron beam by 46.6° and the Scorpius magnet will deflect by 44.6°. These results show that the as-built Scorpius magnet has met design requirements for beam deflection.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Design and Prototyping of a Novel Toroid Magnet System for the MOLLER Experiment at Jefferson Lab

The Thomas Jefferson National Accelerator Facility (JLab) has designed a unique spectrometer system to measure the weak interaction between electrons. The experiment ?Measurement of Lepton-Lepton Electroweak Reaction? (MOLLER) requires leveraging the recent 12 GeV electron beam upgrade and will run in JLab for 3 years. Focusing the signal for the MOLLER experiment requires five water-cooled toroidal magnets, each with unique geometry and with 7-fold symmetry. This system of magnets provides the magnetic field required to separate the incident beam electrons scattered from the target electrons (Møller scattering) and protons (elastic e-p scattering) in a liquid hydrogen target. The conceptual design was developed by the MOLLER collaboration and was given to JLab in the form of amp turns and physical location, with additional physics requirements. This paper presents prototyping of the coils and magnet support system and discusses the lessons learned during the process along with the plans for full magnet testing and installation. The JLab Magnet Group along with the MOLLER collaboration developed the specification document that includes keep out zones to design the set of magnets. JLab contracted the design of the first toroid magnet in the magnet (TM0) to Massachusetts Institute of Technology. The other four toroid magnets (TM1 through TM4) have been designed by JLab and are in the process of fabrication and assembly. Prototype coils of TM1-TM4 have been fabricated by Everson-Tesla Incorporated, PA (USA). The manuscript presents the unique challenges of the design, alignment, high current density, operating range, high radiation dose, and vacuum environment.

Kashy, David↗
DOE OSTI2024

Re-assembly and test of COMB dipole magnet with STAR® wires

Fermilab is developing the Conductor on Molded Barrel (COMB) magnet technology that works well with round REBCO conductors. COMB-STAR-1 magnet based on STAR wire by AMPeers was fabricated and tested in liquid nitrogen in 2023. The magnet demonstrated >90 Ic retention in the coils (before/after winding). Even though the magnet was not originally designed for operation at lower than 77 K temperatures, it was decided to test it in liquid helium to: - check the instrumentation and the DAQ system; - check the ability to detect resistive transitions or quenches and to protect the magnet; - gather the information on possible magnet design chances and upgrades of the test facility for future testing of HTS magnets. The magnet was re-assembled with a larger iron yoke and the axial supports and tested in liquid helium in 2024 at Fermilab s Vertical Magnet Test Facility (VMTF). It was the first HTS magnet test at that facility ever.

Kashikhin, Vadim↗
DOE OSTI2024

Measurement of the thermal effects in the dispersion relation of the dust acoustic wave in the presence of a magnetic field

This award supported an experimental study of the properties of the dust acoustic wave, low-frequency, l ongitudinal wave mode that propagates through the dust component of a dusty plasma system and is self-excited by the free energy from the ion streaming p ast the dust, in the presence of a high magnetic fiel d. In particular, this project measured the thermal state of dusty plasma system by measuring the dispersi on relation of the dust acoustic wave while varying (1) the strength and direction of the magnetic field relative to the propagation direction of the wave and (2) the neutral gas pressure. By exploiting the unique ability of the MDPX facility to generate a dusty plasma in a high magnetic field environment, it is possible to create a preferential ion flow along the magnetic field lines as the ions become magnetized. In this way, the magnetic field strength can be used to control t he strength of the ion flow through the dust cloud an d provide insight into the contribution that one of the physical mechanisms, a two-stream ion-dust instability, thought to be responsible for high temperatures that have been previously observed might have. This work was completed over two, one-week long runs o n the Magnetized Dusty Plasma eXperiment (MDPX) in the Magnetized Plasma Research Laboratory at Auburn University and supported by work at Wittenberg University (development of an electrode system that would allow for the wave mode to propagate in th e direction of gravity as the orientation of the magnetic field is changed by rotating the magnets on the M DPX device, analysis of data acquired during the experimental campaigns, testing alternative strategies to form a dust cloud based on what was learned the first experimental campaign, etc.).

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Non-Equilibrium Effects in Quantum Magnets

While most often the state of a material will tend toward an equilibrium determined by its environment, there are many cases of scientific and technological interest where materials are manipulated to be or are found in non-equilibrium configurations. For example, data can be stored in hard drives by deliberately altering the magnetic orientation in a material to store information in non-equilibrium pattern. In this project, the main goals were studies of non-equilibrium properties of quantum magnets using neutron scattering as the primary experimental method. Neutron scattering allows characterization of magnetic correlation lengths sensitive to the presence of defects. It can also be used to distinguish equilibrium from non-equilibrium states via energy transfer rates. Typical bulk state magnetization relaxation times are too short to perform many neutron scattering measurements of interest. To enable the study of non-equilibrium conditions, materials with longer magnetic relaxation times were targeted. CoNb 2 O 6 was used in two experiments related to non-equilibrium physics. In the first, evidence for defects created via the Kibble-Zurek mechanism (KZM) was sought by quenching across a magnetic field-dependent phase transition. Somewhat unexpectedly, clear evidence for KZM-induced defects was absent. Additional measurements of CoNb 2 O 6 were made to better characterize its crystal field and other properties to provide a better theoretical understanding to enable more effective non-equilibrium physics measurements. In another project, LiHo 0.45 Y 0.55 F 4 was used to compare a quantum annealing protocol to a thermal annealing one since magnetic fields can be used to control the thermal fluctuations in LiHo 0.45 Y 0.55 F 4 . In addition, a new pulsed magnet power supply and new techniques were developed suitable for neutron scattering experimental environments to enable faster magnetic field changes for producing non-equilibrium conditions. The power supply developed for this project has wider technological applications in addition to faster magnetic field ramps.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Additive manufacturing of amorphous metal soft magnetic composites

Soft magnet alloys are used as magnetic cores for electric motors, transformers, wind turbines and other power generation systems. Soft magnetic cores are expensive and time consuming to manufacture in the complex shapes required for next-generation devices using conventional press and sinter powder metallurgy. The objective of this effort is to additively manufacture high performance soft magnets, with reduced cost and reduced material waste and 10x lower energy (core) loss at the high operating frequencies of many electric machines. Laser powder bed fusion additive manufacturing is used as the fabrication method. Electrical steel and amorphous alloys atomized powders are used as a feedstock materials. Magnetic cores are printed in topology optimized structures such as the Hilbert curve because this has been shown to reduce energy losses by minimizing the eddy currents that circulate within the magnet at high frequencies. In our project, we succeed in printing FeSi 3.5wt% and FeSi 6.5wt% electrical steels, and iron-based soft magnetic amorphous alloys in the shape of Hilbert and Peano curve topology optimized structures. We found that the Peano curve has a higher cut-off frequency than the Hilbert curve, and that amorphous alloys have high cut-off frequencies and higher mechanical hardness than electrical steels. Processing conditions such as laser power, scan speed, and hatching pattern were optimized to achieve high density prints, and optimize magnetic performance. We find that the printing of amorphous alloy soft magnetic cores may be technoeconomically feasible for large scale applications such as transformers, for which supply chain issues and the labor costs of manual fabrication of magnetic cores is prohibitive in some cases.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Methods and apparatus for making magnetic skyrmions

A system and a method for the deterministic generation of magnetic skyrmions includes a magnetic strip configured to store and transport skyrmions. The magnetic strip includes one or more spatial inhomogeneities configured to generate a skyrmion at known locations when excited by a current pulse. A current pulse generator is used to inject current pulses into the magnetic strip via contact pads electrically coupled to both the current pulse generator and the magnetic strip. The system also includes a magnetic field source to apply an out-of-plane magnetic field across the magnetic strip to facilitate generation of skyrmions. Skyrmions can be generated by applying an out-of-plane magnetic field to the magnetic strip and injecting a current pulse with sufficient current density towards the spatial inhomogeneities. Once a skyrmion is generated, another current pulse with sufficient current density can be injected to move the skyrmion.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Understanding magnetic phase coexistence in Ru 2 Mn 1-x Fe x Sn Heusler alloys: A neutron scattering, thermodynamic, and phenomenological analysis

The random substitutional solid solution between the antiferromagnetic (AFM) full-Heusler alloy Ru 2 MnSn and the ferromagnetic (FM) full-Heusler alloy Ru 2 FeSn provides a rare opportunity to study FM-AFM phase competition in a near-lattice-matched, cubic system, with full solubility. At intermediate x in Ru 2 Mn 1-x Fe x Sn this system displays suppressed magnetic ordering temperatures, spatially coexisting FM and AFM order, and strong coercivity enhancement, despite rigorous chemical homogeneity. Here, we construct the most detailed temperature- and x-dependent understanding of the magnetic phase competition and coexistence in this system to date, combining wide-temperature-range neutron diffraction and small-angle neutron scattering with magnetometry and specific heat measurements on thoroughly characterized polycrystals. A complete magnetic phase diagram is generated, showing FM-AFM coexistence between x ≈ 0.30 and x ≈ 0.70. Furthermore, important insight is gained from the extracted length scales for magnetic phase coexistence (25–100 nm), the relative magnetic volume fractions and ordering temperatures, and remarkable x-dependent trends in magnetic and electronic contributions to specific heat. An unusual feature in the magnetic phase diagram (an intermediate FM phase) is also shown to arise from an extrinsic effect related to a minor Ru-rich secondary phase. The established magnetic phase diagram is then discussed with the aid of phenomenological modeling, clarifying the nature of the mesoscale phase coexistence with respect to the understanding of disordered Heisenberg models.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Magnetic‐Field‐Switchable Laser via Optical Pumping of Rubrene

Abstract Volumetric optical imaging of magnetic fields is challenging with existing magneto‐optical materials, motivating the search for dyes with strong magnetic field interactions, distinct emission spectra, and an ability to withstand high photon flux and incorporation within samples. Here, the magnetic field effect on singlet‐exciton fission is exploited to demonstrate spatial imaging of magnetic fields in a thin film of rubrene. Doping rubrene with the high‐quantum yield dye dibenzotetraphenylperiflanthene (DBP) is shown to enable optically pumped, slab waveguide lasing. This laser is magnetic‐field‐switchable: when operated just below the lasing threshold, application of a 0.4 T magnetic field switches the device between nonlasing and lasing modes, accompanied by an intensity modulation of +360%. This is thought to be the first demonstration of a magnetically switchable laser, as well as the largest magnetically induced change in emission brightness in a singlet‐fission material to date. These results demonstrate that singlet‐fission materials are promising materials for magnetic sensing applications and could inspire a new class of magneto‐optical modulators.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Quantum Disordered State of Magnetic Charges in Nanoengineered Honeycomb Lattice

Abstract A quantum magnetic state due to magnetic charges is never observed, even though they are treated as quantum mechanical variables in theoretical calculations. Here, the occurrence of a novel quantum disordered state of magnetic charges in a nanoengineered magnetic honeycomb lattice of ultra‐small connecting elements is demonstrated. The experimental research, performed using spin resolved neutron scattering, reveals a massively degenerate ground state, comprised of low integer and energetically forbidden high integer magnetic charges, that manifests cooperative paramagnetism at low temperature. The system tends to preserve the degenerate configuration even under large magnetic field application. It exemplifies the robustness of disordered correlation of magnetic charges in a 2D honeycomb lattice. The realization of quantum disordered ground state elucidates the dominance of exchange energy, which is enabled due to the nanoscopic magnetic element size in nanoengineered honeycomb. Consequently, an archetypal platform is envisaged to study quantum mechanical phenomena due to emergent magnetic charges.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

The Magneto-Transport Properties of Cr 1/3 TaS 2 with Chiral Magnetic Solitons

Cr 1/3 TaS 2 —a candidate of chiral magnet—has been reported as a trivial ferromagnetic material. In contrast, the Cr 1/3 TaS 2 single crystals exhibit a chiral helimagnetic (CHM) transition near 140 K. The magnetic moment versus magnetic field curves reveal a CHM—chiral soliton lattice (CSL)—forced ferromagnetic (FFM) transition in the magnetic ordered state. The conducting electrons interact with the CHM and CSL orders, giving rise to the nontrivial magnetoresistance (MR) in the Cr 1/3 TaS 2 single crystals. The normalized magnetic moment and normalized MR fit well with the analytical functions for chiral soliton density. The magnetic phase diagrams constructed from the magnetic moment data and MR data suggest a possible tri-critical point. Compared with the isostructural Cr 1/3 NbS 2 , the CHM transition temperature of Cr 1/3 TaS 2 is 13 K higher, the CSL—FFM transition field is about 10 times larger, and the Dzyaloshinskii-Moriya interaction strength is 3 times bigger. The latter two likely originate from the strong spin-orbit coupling (SOC) of Cr 1/3 TaS 2 . This work clarifies that high-quality Cr 1/3 TaS 2 single crystals are chiral magnets and Cr 1/3 (Nb,Ta)S 2 could serve as an intriguing platform for the flexible engineering of chiral magnetic solitons with tunable SOC.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Development of rare-earth-free bulk magnets with energy product up to 12 MGOe in field annealed Mn–Bi–Mg–In–Sb alloys

A treatment consisting of annealing in a moderately strong, ≤30 kOe, magnetic field was applied to arc-melted ingots and compacted melt-spun alloys with composition Mn 50 Bi 50-x-y-z Mg x In y Sb z . The high degree of texture of the magnetic α phase induced with annealing of the ingot samples (except the Mn–Bi–Sb one) allowed for accurate determination of the phase anisotropy field. Alloying was found to increase the anisotropy field from 45 kOe in the Mn 50 Bi 50 alloy to 65 kOe in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 alloy. In the compacted melt-spun alloys subjected to field annealing, a higher degree of texture could be achieved after compaction which had involved less heating, when a smaller fraction of the metastable β' phase had been converted into the α phase; compaction at room temperature allowed for the highest degree of texture in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 magnet. The addition of indium was found to decrease the solidus temperatures of the alloys, facilitating the development of the α phase during the field annealing and modifying the properties of the resulting magnets. Introduction of indium resulted in a higher coercivity H c of the Mn–Bi–Mg–In magnets and in a better texture of the Mn–Bi–Mg–Sn–In magnets. The former effect allowed, in particular, for a viable maximum energy product ( BH ) max of 10 MGOe to be developed in the Mn 50 Bi 46.5 Mg 3 In 0.5 magnet through annealing in a relatively low field of 15 kOe, whereas the latter effect allowed for an excellent combination of ( BH ) max = 11.6 MGOe and H c = 8.5 kOe in the Mn 50 Bi 45 Mg 3 In 0.5 Sb 1.5 magnet. The highest ( BH ) max of 12 MGOe was realized in the Mn 50 Bi 46 Mg 3 In 0.5 Sb 0.5 magnet.

36 MATERIALS SCIENCE↗