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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Generation of Rare Earth Metals from Rare Earth Oxide Using Microwave Plasmas

The overarching goal of the proposed project is to develop a simple, energy-saving, high-selectivity technology for efficiently converting rare-earth oxides (REOs) to rare-earth metals (RE-metals) using microwave plasma under low temperature and inexpensive H 2 and N 2 . The project was managed and led by Dr. Maohong Fan at the University of Wyoming. The collaborating institutions include Ames Lab and Colorado School of Mines. The industrial collaboration entity is Eutectix, LLC. The use of hydrogen to reduce rare earth oxides has many advantages, as it is renewable and does not produce harmful emissions during metal production. Also, it avoids the use of carbon and the emission of CO 2 . Nd 2 O 3 treated with hydrogen plasma shows new peaks alongside those of Nd 2 O 3 . Some of these peaks are close to (28.4, 29.4, 30.5, 32.3, 36.6, 42.1, 48.9, 50.08, 55.1, 59.05, 59.64, 60.68, 62.5, 63.25), which may be related to elemental Nd.

36 MATERIALS SCIENCE↗
DOE OSTI2025

AL-CRADA-2025-01 Final Report: American-Made Wind Turbine Materials Recycling Prize Accelerate! Phase 2

This report summarizes the Phase 2 achievements of the Wind Turbine Materials Recycling Prize project led by Critical Materials Recycling (CMR) in partnership with Ames National Laboratory. The team demonstrated the technical feasibility and economic viability of recovering and reusing rare-earth Nd-Fe-B magnets from end-of-life (EOL) wind turbine generators. Through mechanical disassembly, demagnetization, and precision processing, magnets were harvested and characterized to assess structural, compositional, and magnetic properties. Results showed that recovered magnets performed on par with commercial-grade counterparts, enabling their integration into actuator and motor prototypes without redesign. System-level modeling and finite-element simulations validated operational performance, while Life Cycle Cost (LCC) analysis revealed up to 20% material cost savings and 2–3% reductions in overall motor system costs. Life Cycle Assessment (LCA) further confirmed substantial environmental benefits, including a ~94% reduction in global warming potential relative to virgin magnet production. The project’s success was enabled by a tightly integrated partnership between industry and national lab experts, illustrating a viable path for domestic magnet-to-magnet recycling. These findings support a scalable, circular solution for rare-earth material recovery, reducing dependence on imported critical minerals and advancing sustainable clean energy technologies.

Lograsso, Thomas [Ames Laboratory (AMES), Ames, IA↗
DOE OSTI2026

Electronic Trap-State Modulation in Sm-Doped SnO 2 Nanofibers Enables Ultrasensitive Hydrogen Sensing

The demand for sub-ppm hydrogen (H 2 ) sensing is growing across emerging applications such as environmental monitoring, breath-based disease diagnostics, and early-stage battery failure detection. However, achieving reliable ppb-level detection with chemiresistive metal oxide sensors remains challenging. At trace gas concentrations, resistance modulation is often insufficient, particularly in the absence of noble metal catalysts. Here, we report samarium-doped tin dioxide (Sm-SnO 2 ) nanofibers in which electronic trap-state modulation is exploited to enable ultrasensitive hydrogen sensing. The 2 at% Sm-doped SnO 2 nanofibers exhibited markedly enhanced H 2 sensitivity, achieving clear detection down to 25 ppb H 2 at 200 °C, with a theoretical limit of detection of 4.5 ppb, placing this material among the most sensitive noble-metal-free SnO 2 -based H 2 sensors reported to date. Mechanistic investigations through X-ray photoelectron spectroscopy and electron energy loss spectroscopy revealed that Sm 3+ doping introduces deep trap states associated with charge-compensating defect complexes. These states reduce free carrier density, increase baseline resistance, and enable trap-assisted charge release during H 2 exposure, thereby amplifying the sensing response. Trap-state engineering via rare-earth doping, exemplified by Sm-SnO 2 , provides an effective pathway for achieving ppb-level hydrogen detection in noble-metal-free chemiresistive sensors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Magnetic order and excitations in Ce 3 TiBi 5 and Ce 3 ZrBi 5

The R 3 MBi 5 rare-earth intermetallics (R = rare earth, M = Ti, Zr, Sc) provide a versatile platform to explore how Kondo hybridization, Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange, magnetic frustration, and broken inversion symmetry may cooperate to generate unusual magnetic behavior. We present a comprehensive neutron scattering investigation of the magnetic structure, crystal electric field (CEF), and low-energy excitations in the locally noncentrosymmetric Kondo-lattice compounds Ce 3 TiBi 5 and Ce 3 ZrBi 5 . Powder and single-crystal neutron diffraction reveals incommensurate cycloidal antiferromagnetic order in Ce 3 TiBi 5 with propagation vector k = (0, 0, 0.388) and a reduced ordered moment of m = 0.53(3)μ B . Ce 3 ZrBi 5 exhibits a qualitatively similar magnetic diffraction profile, with k ≃ (0, 0, 0.37). Inelastic neutron scattering measurements resolve two clear, well-separated CEF excitations in both compounds with nearly the same profile, confirming a well-isolated Kramers doublet ground state. At low energies, a broad, quasi-elastic magnetic response is observed at T ≃ T N , whose momentum-dependence is inconsistent with that expected from conventional collective excitations of localized moments. This discrepancy, along with a Kondo temperature estimate T K ~ 6 - 7 K—comparable to T N —indicates sizable Kondo hybridization, which accounts for the moment reduction and the spiral magnetic order that appears to involve the magnetic hard direction. Our results place these compounds in a regime where local inversion symmetry breaking, anisotropic CEF effects, and competing Kondo and RKKY interactions collectively give rise to unconventional magnetic order.

Kondo interaction↗
DOE OSTI2026

Critical transverse compressive stresses of straight and bent CORC® wires with and without impregnation

CORC® wires are a promising superconductor for accelerator magnet applications. While their excellent uniaxial tensile properties have been well established, potential degradation under transverse compression remains a concern for accelerator magnets, in which transverse compression is a primary stress experienced by superconductors. To evaluate the critical transverse compressive stresses of rare-earth barium copper oxide conductors, we developed an experimental system that enables testing of samples both with and without impregnation in liquid nitrogen. Furthermore, because bending strain induced during coil winding may influence the critical compressive response of CORC® wires, the apparatus was also modified to allow testing under the bending condition. In this study wires were tested for five configurations: (1) straight, non-impregnated, (2) bent, non-impregnated, (3) straight, Stycast 2850 FT-impregnated, (4) bent, Stycast 2850 FT-impregnated, and (5) bent, paraffin wax-impregnated. The transverse pressures corresponding to 3% and 5% reductions in the critical current are reported. In conclusion, the effects of wire bending and impregnation on the critical transverse pressure are analyzed, and the implications for transverse stress levels in accelerator magnet conductors are discussed.

CORC® wire↗
DOE OSTI2026

Pressure-induced 𝐵⁢1 to 𝐵⁢2 phase transition in CeN studied by 𝑎⁢𝑏 𝑖⁢𝑛⁢𝑖⁢𝑡⁢𝑖⁢𝑜 correlation matrix renormalization theory calculations

We apply correlation matrix renormalization theory (CMRT) to cerium nitride (CeN) under pressure. For 𝐵⁢1 (NaCl-type) phase, CMRT gives an equation of state consistent with ambient pressure experiments. It produces electronic density-of-state (DOS) characterized by a sharp 4⁢𝑓 quasiparticle resonance peak pinned at the Fermi level and two subbands formed by strong hybridization between the localized Ce-4⁢𝑓 electrons and the itinerant Ce-5⁢𝑑 and N-2⁢𝑝 electrons below the Fermi level, consistent with x-ray photoemission spectroscopy experiments. Upon compression, CMRT predicts a first-order 𝐵⁢1 → 𝐵⁢2 (CsCl-type) transition with ∼11% volume collapse in agreement with experiments. Across the transition, the 4⁢𝑓 spectrum broadens, the 4⁢𝑓 orbital occupancy increases, and the hybridization with conduction states enhances, signaling a crossover from partially localized to more itinerant 4⁢𝑓 behavior. Furthermore, these features are in excellent agreement with experimental observations, demonstrating that CMRT provides a parameter-free description and prediction of correlation-driven structural and electronic transitions in rare-earth compounds.

Ab initio calculations↗
DOE OSTI2026

Emergent quasi-one-dimensional antiferromagnetism in the distorted kagome magnet CePtPb

CePtPb hosts a distorted kagome lattice of Ce 3+ ions, providing a clean platform to investigate how reduced local symmetry and strong spin-orbit coupling reshape frustrated magnetism. Magnetization, specific heat, and magnetocaloric effect measurements, combined with a symmetry analysis of the single-ion anisotropy, demonstrate that the local 𝑚⁢2⁢𝑚 site symmetry selects a nearly Ising-like Kramers doublet with easy axes lying within the 𝑎⁢𝑏 plane. This results in three distinct in-plane Ising directions and an overall easy-plane anisotropy. The low-energy magnetic response is well captured by a three-sublattice Ising model, which quantitatively reproduces the saturation magnetization for arbitrary in-plane field orientations, including $[110]$ and $[1\bar{⁢1}⁢0]$, as well as the ratio of the field-induced critical fields. For 𝐵∥$[110]$, the phase diagram exhibits two quantum critical points at 𝐵 c⁢1 = 0.25T and 𝐵 c⁢2 = 0.55T, arising from the sequential polarization of the three Ising sublattices. In conclusion, these results reveal that the system develops quasi-one-dimensional spin chains along the 𝑐 axis, emerging from the nominally three-dimensional crystal structure composed of stacked kagome layers, and illustrate how reduced local symmetry can drive effective dimensional reduction in rare-earth Ising magnets.

Li, Fangli [Southern University of Science and Tec↗
DOE OSTI2026

Achieving uniaxial magnetic anisotropy in Ce2⁢Fe17⁢N3 through Co- and Sm-substitution

Th2⁢Zn17−type structure-based permanent magnets, such as Sm2⁢Fe17⁢N3, offer strong potential as alternatives to neodymium magnets (NdFeB), but their practical use is limited by phase stability and the scarcity of Sm. Ce-based counterparts, particularly Ce2⁢Fe17⁢N3, are attractive low-cost candidates, yet their intrinsic planar magnetic anisotropy restricts permanent-magnet performance. Here, we induce uniaxial magnetic anisotropy in Ce2⁢Fe17⁢N3 through two approaches: (i) Co substitution on the Fe sublattice and (ii) partial substitution of Ce with Sm. Combined density functional theory and experimental results show that both strategies modify the 3⁢𝑑–4⁢𝑓 interactions and band filling, yielding magnetization values up to ∼1.2T and magnetocrystalline anisotropy energies exceeding 1MJ/m3 for Co-alloyed compositions, with significantly larger anisotropy achieved upon Sm substitution. In addition, the Sm-substituted Ce2⁢Fe17⁢N3 samples exhibit enhanced high-temperature stability compared to Sm2⁢Fe17⁢N3. These findings demonstrate that Ce2⁢Fe17⁢N3-based alloys can deliver magnetic performance suitable for permanent-magnet applications while reducing cost and reliance on critical rare-earth elements, and they provide practical design guidelines for rare-earth-lean magnets for energy and industrial applications.

Pokhrel, Nabaraj [ORNL] (ORCID:0000000328283076)↗
DOE OSTI2026

Chiral Magnon Mixing by Symmetry-Breaking in Collinear Ferrimagnets

Magnons in ferromagnets possess spin angular momentum defined by right-handed precession of the moment around the magnetization direction. In antiferromagnets with no net magnetization, left- and right-handed magnons are degenerate in the absence of an applied field. Ferrimagnets possess uncompensated magnetic sublattices, which should natively possess right- and left-handed magnons where their energy is split by the internal molecular field. Here, we show that 𝑅⁢Mn6⁢Sn6 (𝑅 =Tb, Er) ferrimagnets possess right- and left-handed magnon bands that cross at finite momentum (𝐤) within the basal plane, defining modes with opposite dynamical chirality. Depending on the symmetry of the ferrimagnetic order, which may be manipulated by varying the rare-earth magnetic anisotropy or with an applied field, the band crossing may remain a nodal line or may be gapped. The gapped modes contain hybridized chiral excitations whose chirality becomes 𝐤-dependent.

Jaishi, Dhurba R [Ames Laboratory]↗
DOE OSTI2026

Influence of controlled disorder on the dipolar spin-ice state of Ho-based pyrochlores

Pyrochlore magnets of the form 𝑅 2 ⁢𝐵 2 ⁢O 7 , in which rare-earth ions on the 𝑅 site form a three-dimensional network of corner-sharing tetrahedra, provide a canonical setting for geometrical frustration. Ho-based pyrochlores host a dipolar spin-ice ground state, characterized by Ising moments constrained by the ice rules and elementary excitations analogous to magnetic monopoles. Here, in this work, we examine how controlled chemical disorder influences this state by introducing site mixing on the nonmagnetic 𝐵 site in two compounds. Ho 2⁢ GaSbO 7 contains only Ga 3+ /Sb 5+ charge disorder, whereas Ho 2 ⁢ScSbO 7 exhibits both charge and substantial size disorder arising from the large ionic-radius mismatch between Sc 3+ and Sb 5+ . Although both materials retain the pyrochlore structure, neutron-scattering measurements reveal a reduced correlation length for the 𝑅/𝐵-site cation ordering and enhanced local structural distortions in Ho 2 ⁢ScSbO 7 . Despite these structural differences, bulk thermodynamic measurements and magnetic diffuse scattering demonstrate that both systems exhibit the defining signatures of a dipolar spin-ice state. Low-energy inelastic neutron spectroscopy further uncovers broad magnetic excitations that develop within the dipolar spin-ice regime, a feature absent in pristine Ho pyrochlores and indicative of disorder-induced splitting of the non-Kramers ground-state doublet. Together, these results show that controlled disorder generates tunable transverse-field-driven quantum fluctuations in Ho-based pyrochlores, although the dipolar spin-ice state is remarkably robust to this disorder.

magnetic anisotropy↗
DOE OSTI2026

Observing the effects of numbers of valence nucleons on 0$^{+}_{𝑔⁡𝑠}$ → 2$^{+}_{1}$ transitions in deformed nuclei by comparing proton and neutron transition matrix elements

We examined the ratios of neutron and proton transition matrix elements, 𝑀 𝑛 /𝑀 𝑝 , for the 0$^{+}_{𝑔⁡𝑠}$ → 2$^{+}_{1}$ transitions in 48 even-even stable nuclei with 𝑁 > 20 for which electromagnetic matrix elements were compiled by Pritychenko et al. and for which high-quality inelastic proton-scattering data were available. Several deformed rare-earth nuclei have (𝑀 𝑛 /𝑀 𝑝 )/(𝑁/𝑍) values significantly below 1.0, which is not consistent with a simple liquid-drop picture. However, this phenomenon can be explained using a schematic picture in which 𝑀 𝑝 reaches a maximum at proton midshell (𝑍 = 66) and 𝑀𝑛 reaches its maximum at neutron midshell (𝑁 = 104). Several midmass vibrational nuclei have 𝑀 𝑛 /𝑀 𝑝 values significantly below 𝑁/𝑍, which is not consistent with the expectation that 𝑀 𝑛 /𝑀 𝑝 = 𝑁/𝑍 in such nuclei. As a result, a shell-model investigation of these observations might yield insights about this behavior.

Collective levels↗
DOE OSTI2026

Er Al :Al 2 ⁢O 3 for telecom-band photonics: Electronic structure and optical properties

Er-doped Al 2 ⁢O 3 is a promising host for telecom-band integrated photonics. Here, in this study, we combine ab initio calculations with a symmetry-resolved analysis to elucidate substitutional Er on the Al site (Er Al ) in 𝛼−Al 2 ⁢O 3 . First-principles relaxations confirm the structural stability of Er Al . We then use the local trigonal crystal-field symmetry to classify the Er-derived impurity levels by irreducible representations and to derive polarization-resolved electric-dipole selection rules, explicitly identifying the symmetry-allowed 𝑓−𝑑 hybridization channels. Kubo-Greenwood absorption spectra computed from Kohn-Sham states quantitatively corroborate these symmetry predictions. Furthermore, we connect the calculated intra-4⁢𝑓 line strengths to Judd-Ofelt theory, clarifying the role of 4⁢𝑓−5⁢𝑑 admixture in enabling optical activity. Notably, we predict a characteristic absorption near 1.47 µ⁢m (telecom band), relevant for on-chip amplification and emission. To our knowledge, a symmetry-resolved first-principles treatment of Er:Al 2 ⁢O 3 with an explicit Judd-Ofelt interpretation has not been reported, providing a transferable framework for tailoring rare-earth dopants in wide-band-gap oxides for integrated photonics. Our results for the optical spectra are in good agreement with experimental data. The resulting symmetry-based selection rules translate directly to polarization-dependent coupling in Al 2 ⁢O 3 integrated photonic waveguides and resonators, enabling device-level design of TE/TM-mode interaction with Er emitters in the 1.5-µ⁢m telecom band.

Er-doped Al2O3↗
DOE OSTI2026

Isomeric states in the neutron-rich 𝑁 = 108 nuclei 178 Yb and 179 Lu

A multinucleon transfer reaction with a 136 Xe beam and a gold-backed 176 Yb target populated isomers in N = 108 178 Yb and 179 Lu. The single decay from the t 1/2 = 203(16) ns isomer in 178 Yb to the I π = 4 + level in the ground-state band suggests a I π = 4 − assignment, and multiquasiparticle calculations associate this state with the K π = 4 − , ν 2 (1/2[510], 9/2[624]) configuration. At least two isomers were observed in 179 Lu. One likely couples the K π = 4 − configuration found in 178 Yb to the 9/2[514] quasiproton orbital to form a K π = 17/2 + level (t 1/2 = 1.0(4) µs) which primarily decays into the rotational band based on the 9/2[514] state. A second isomer was observed to decay into this same band, but at higher energy and spin. Based on its feeding pattern, its similarity to an isomer found in 181 Ta, and a multiquasiparticle calculation, it is proposed to correspond to a K π = 29/2 − state based on the π9/2[514]ν 2 (9/2[624], 11/2[615]) configuration. As a result, an analysis of the reduced hindrance factors for negative-parity, two-quasineutron isomers in the rare-earth region is presented as well.

150 ≤ A ≤ 189↗
DOE OSTI2026

Experimental Results for an Inverter Integrated with A High-Speed Surface Permanent Magnet External Rotor Motor

This work presents the prototyping and testing of a high-speed outer rotor surface permanent magnet motor. The motor employs non-heavy rare-earth permanent magnets and operates at a rated speed of 6,666 rpm. In-slot ceramic heat exchangers are used to cool the windings. The external rotor configuration provides substantial space within the stator bore, which is used for power electronics integration. This integration introduces several design and thermal management challenges that are discussed in the paper. The machine has been prototyped and tested under various operating conditions, and both simulation and experimental results are presented.

Rallabandi, Vandana [ORNL] (ORCID:0000000236241901↗
DOE OSTI2026

Lifetimes of negative parity states in 162 Dy

Lifetimes of excited states in 162 Dy were measured using the (n,n’$γ$) reaction with the Doppler-Shift Attenuation Method (DSAM) at the University of Kentucky’s Accelerator Laboratory. A total of eighteen level lifetimes were obtained, including eleven negative-parity states, seven of which are new. These measurements significantly expand the experimental database of transition probabilities for negative-parity bands in the well-deformed rare earth region of nuclei. The extracted B(E1) and B(E2) values reveal enhanced interband E1 (10 -3 or 10 -4 ) W.u. and E2 strengths (several W.u.) between negative- and positive parity bands, particularly for the K π = $2^{-}_{1,2}$ bands decaying to the K π = $2^+_γ$ band, consistent with signatures of octupole-quadrupole coupling. In contrast, the K π = $0^{-}_1$ and K π = $1^{-}_3$ bands, which exhibit strong E1 transitions to the ground state band, are indicative of octupole-vibrational excitations built on the deformed ground state. Comparison of transition rates with Alaga rules supports this interpretation and distinguishes collective excitations from likely quasi-particle states. These new results establish 162 Dy as the most extensively characterized rare-earth nucleus for negative parity lifetimes and provide critical experimental benchmarks for theoretical models.

Aprahamian, A. [University of Notre Dame, IN (Unit↗
DOE OSTI2025

Analysis of Liquids Using the Submerged Plasma for Isotopic Detection and Elemental Resolution (SPIDER)

We developed a sensor called the Submerged Plasma for Isotopic Detection and Elemental Resolution (SPIDER) probe, which uses an atmospheric pressure glow discharge below the surface of liquids to excite species in the liquid. Through emission spectroscopy of molten salts, liquid metals, and heavy water, we demonstrated the SPIDER probe’s high resolution, accuracy, and versatility. We successfully identified trace concentrations of transition and rare-earth metals in molten salts and detected the isotopic shift of the H β → D β emission line. Our analysis revealed unconventional spectral alkali line shapes, indicating two competing excitation modes: film explosion and droplet vaporization. The film explosion mode, characterized by dense plasma, exhibited self-reversal and broadband continuum emission, while the droplet vaporization mode, associated with diffusive plasma, produced narrow-line emissions. Furthermore, by analyzing circuit transients alongside individual plasma events, we observed that film explosions generate higher currents, likely due to a shorter plasma length as the current preferentially flows through the thin liquid layer. Altogether, our results highlight the SPIDER probe’s efficacy and flexibility, making it well-suited for online material quantification of liquids in extreme environments.

AES↗
DOE OSTI2026

Atomic Manipulation of Single Erbium on GaAs(110): From Adatom Motion to Creation and Control of Bistable Substitutions

We demonstrate atomic-scale control over the position and configuration of single erbium (Er) atoms at the GaAs(110) surface using scanning tunneling microscopy (STM). By applying voltage pulses from the STM tip, we drive Er adatoms to move sequentially among three distinct adsorption sites and controllably substitute into Ga lattice sites. The resulting substitutional Er atoms exhibit two isoelectronic configurations that differ by less than one angstrom in lateral position and can be reversibly switched by additional voltage pulses. Differential conductance spectroscopy shows differences in the unoccupied local electronic states for the two substitutional configurations, and an absence of mid-gap states. Preliminary density functional theory (DFT) calculations support these findings, identifying the most stable adsorption and substitutional sites, their relative binding energies, charge states, and local density of states (LDOS) characteristics. Together, the experimental and theoretical results establish a method for precise, reversible manipulation of rare-earth dopants at semiconductor surfaces, opening a pathway to engineer atomic-scale quantum and optoelectronic functionalities.

Poche, Steven [Ohio State University]↗
DOE OSTI2026

Brushless Excitation for Wound-field Synchronous Machines using Multi-harmonic Windings

Wound-field synchronous machines (WFSM) are promising alternatives to electric machines with permanent magnets (PM). The ability to control the rotor field in these machines makes them well-suited to safety critical applications, while the absence of rare-earth permanent magnets makes these machines sustainable. The WFSM rotor excitation schemes have traditionally used carbon brushes, which significantly reduces the reliability of these machines, limiting their widespread adoption. To overcome this limitation and improve the reliability of WFSMs, several brushless rotor excitation schemes have been developed. However, most of these systems require additional windings or dedicated power electronics, making them expensive and limiting achievable power-density. In this paper a new brushless excitation scheme is proposed. In this scheme, a multiphase, multi-harmonic stator winding is designed. This winding can independently control two spatial harmonics in the airgap of the machine; the first to create torque and the second to wirelessly transfer power to the rotor to excite it.

Gadiyar, Nishanth [ORNL] (ORCID:0000000348267524)↗