Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Sm”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Bi-modal particle size distribution for high energy product hybrid Nd–Fe–B—Sm–Fe–N bonded magnets

In this work, we have demonstrated high energy product bonded magnet by leveraging the variation in sizes between Nd-Fe-B and Sm-Fe-N, as well as their hard magnetic properties. The hybrid anisotropic bonded magnets contain 70 vol% of magnet powder (Dy-free Nd-Fe-B and Sm-Fe-N) and 30 vol% of nylon. The objective of the work was to create bi-modal and bi-compositional bonded magnets in which the fine (3μm) particles of Sm-Fe-N would be used to fill the voids between the bigger Nd-Fe-B (105μm) particles, thus improve packing density. The magnetic hysteresis loop did not show significant signs of decoupled interactions between the magnetic phases. It was also found that the performance of the bonded magnet was most enhanced at 1:4 ratio of Nd-Fe-B and Sm-Fe-N. At that ratio, maximum density of 5 g/cm 3 and the highest (BH) max value of 18.5 MGOe were obtained, although the intrinsic coercivity decreased, relative to the trend seen for other ratios. This work advances the opportunity to expand the use of Sm-Fe-N in bonded magnet applications.

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

Materials Data on Sm(BO2)3 by Materials Project

SmB3O6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.33–2.93 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.34–2.67 Å. In the third Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.41–2.71 Å. In the fourth Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.37–2.61 Å. There are six inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.54 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There is two shorter (1.47 Å) and two longer (1.48 Å) B–O bond length. In the third B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.54 Å. In the fourth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.47–1.52 Å. In the fifth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.53 Å. In the sixth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.52 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three B3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sm3+ and two equivalent B3+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sm3+ and two B3+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sm3+ and two equivalent B3+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Sm3+ and two B3+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sm3+ and two B3+ atoms. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Sm3+ and two equivalent B3+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sm3+ and two B3+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sm3+ and two B3+ atoms. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to three Sm3+ and one B3+ atom. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Sm3+ and two equivalent B3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Sm3+ and two B3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sm3+ and two equivalent B3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sm3+ and two B3+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Sm3+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(MnSn)6 by Materials Project

SmMn6Sn6 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Sm is bonded to eight Sn atoms to form distorted edge-sharing SmSn8 hexagonal bipyramids. There are two shorter (3.03 Å) and six longer (3.16 Å) Sm–Sn bond lengths. Mn is bonded in a 12-coordinate geometry to six Sn atoms. There are a spread of Mn–Sn bond distances ranging from 2.75–2.84 Å. There are three inequivalent Sn sites. In the first Sn site, Sn is bonded in a 12-coordinate geometry to three equivalent Sm and six equivalent Mn atoms. In the second Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Mn atoms. In the third Sn site, Sn is bonded in a 8-coordinate geometry to one Sm, six equivalent Mn, and one Sn atom. The Sn–Sn bond length is 2.99 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(Ge3Pt)4 by Materials Project

Sm(PtGe3)4 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Sm is bonded to twelve equivalent Ge atoms to form SmGe12 cuboctahedra that share faces with eight equivalent PtGe6 octahedra. All Sm–Ge bond lengths are 3.35 Å. Pt is bonded to six equivalent Ge atoms to form PtGe6 octahedra that share corners with six equivalent PtGe6 octahedra and faces with two equivalent SmGe12 cuboctahedra. The corner-sharing octahedral tilt angles are 60°. All Pt–Ge bond lengths are 2.51 Å. Ge is bonded in a 2-coordinate geometry to one Sm, two equivalent Pt, and two equivalent Ge atoms. There are one shorter (2.56 Å) and one longer (2.64 Å) Ge–Ge bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(NO3)3 by Materials Project

Sm(NO3)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to twelve O2- atoms to form corner-sharing SmO12 cuboctahedra. There are a spread of Sm–O bond distances ranging from 2.59–2.63 Å. In the second Sm3+ site, Sm3+ is bonded to twelve O2- atoms to form distorted corner-sharing SmO12 cuboctahedra. There are a spread of Sm–O bond distances ranging from 2.57–2.76 Å. In the third Sm3+ site, Sm3+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Sm–O bond distances ranging from 2.50–2.78 Å. There are six inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.30 Å) N–O bond length. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.30 Å. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.30 Å) N–O bond length. In the fourth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.29 Å) N–O bond length. In the fifth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.25 Å) and two longer (1.28 Å) N–O bond length. In the sixth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.25–1.30 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Sm3+ and one N5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two Sm3+ and one N5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two Sm3+ and one N5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two Sm3+ and one N5+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Sm3+ and one N5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Sm3+ and one N5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sm(GaSe2)2 by Materials Project

Sm(GaSe2)2 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Sm2+ sites. In the first Sm2+ site, Sm2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Sm–Se bond distances ranging from 3.06–3.15 Å. In the second Sm2+ site, Sm2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.07 Å) and four longer (3.13 Å) Sm–Se bond lengths. In the third Sm2+ site, Sm2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.06 Å) and four longer (3.11 Å) Sm–Se bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing GaSe4 tetrahedra. There are a spread of Ga–Se bond distances ranging from 2.47–2.54 Å. In the second Ga3+ site, Ga3+ is bonded to four Se2- atoms to form a mixture of edge and corner-sharing GaSe4 trigonal pyramids. There are three shorter (2.54 Å) and one longer (2.56 Å) Ga–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two Sm2+ and two Ga3+ atoms to form a mixture of distorted edge and corner-sharing SeSm2Ga2 trigonal pyramids. In the second Se2- site, Se2- is bonded to two Sm2+ and two Ga3+ atoms to form a mixture of distorted edge and corner-sharing SeSm2Ga2 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two Sm2+ and two equivalent Ga3+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Sm2+ and two equivalent Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Hydration of divalent lanthanides, Sm 2+ and Eu 2+ : A molecular dynamics study with polarizable AMOEBA force field

The chemistry of divalent lanthanides, Ln 2+ , is a growing sub-field of heavy element chemistry owing to new synthetic approaches. However, some theoretical aspects of these unusual cations are currently underdeveloped, especially as they relate to their dynamic properties in solution. In this study, we address the hydration of two of the classical Ln 2+ cations, Sm 2+ and Eu 2+ , using atomic multipole optimized energetic for biomolecular applications (AMOEBA) force fields. These cations have not been parameterized to date with AMOEBA, and few studies are available because of their instability with respect to oxidation in aqueous media. Coordination numbers (CN's) of 8.2 and 8.1 respectively for Sm 2+ and Eu 2+ , and 8.8 for both Sm 3+ and Eu 3+ have been obtained and are in good agreement with the few available AIMD and X-ray absorption fine structures studies. The decreased CN of Ln 2+ compared with Ln 3+ arises from progressive water exchange events that indicates the gradual stabilization of 8-coordinate structures with respect to 9-coordinate geometries. Moreover, the effects of the chloride counter anions on the coordination of Ln 2+ cations have been studied at different chloride concentrations in this work. Lastly, water exchange times of Ln 2+ cations have been calculated to provide a comprehensive understanding of the behavior of Eu 2+ and Sm 2+ in aqueous chloride media.

AMOEBA force field parameterization↗
DOE OSTI2025

“Unification” of BSM searches and SM measurements: the case of lepton+E T and m W

We develop the idea that the unprecedented precision in Standard Model (SM) measurements, with further improvement at the HL-LHC, enables new searches for physics Beyond the Standard Model (BSM). As an illustration, we demonstrate that the measured kinematic distributions of the ℓ + E T final state not only determine the mass of the W boson, but are also sensitive to light new physics. Such a search for new physics thus requires a simultaneous fit to the BSM and SM parameters, “unifying” searches and measurements at the LHC and Tevatron. In this paper, we complete the program initiated in our earlier work [1]. In particular, we analyze (i) novel decay modes of the W boson with a neutrinophilic invisible scalar or with a heavy neutrino; (ii) modified production of W bosons, namely, associated with a hadrophilic invisible Z′ gauge boson; and (iii) scenarios without an on-shell W boson, such as slepton-sneutrino production in the Minimal Supersymmetric Standard Model (MSSM). Here, we complement our previous MSSM analysis in [1] by considering a different kinematic region. Our results highlight that new physics can still be directly discovered at the LHC, including light new physics, via SM precision measurements. Furthermore, we illustrate that such BSM signals are subtle, yet potentially large enough to affect the precision measurements of SM parameters themselves, such as the W boson mass.

Electroweak Precision Physics↗
DOE OSTI2025

Structural evolution and magnetic hardness of (Sm,Zr)(Fe,Co,Ti) 12 alloy particles via reduction-diffusion

The quest for achieving high coercivity in Sm(Fe,Co,Ti) 12 alloys, despite their inherent strong magnetocrystalline anisotropy, has posed significant challenges. Recently, (Sm,Zr)(Fe,Co,Ti) 12 monocrystalline particles have exhibited coercivity μ 0 H c > 1.2 T, showcasing promising prospects and significant potential for both manufacturing and research endeavors. This study delves into the structural evolution of (Sm,Zr)(Fe,Co,Ti) 12 (1:12) alloy particles made via the calciothermic reduction-diffusion synthesis process as influenced by the molar ratios of Ca atoms to O 2- ions (Ca/O), annealing time and annealing temperature. Critical insight that informs conditions to optimize the magnetic response is gained via systematic experimentation and advanced electron microscopy. Complex structural features, including core-shell morphologies and intricate multiphase compositions within individual particles, are unveiled. An optimal Ca/O ratio of 1.30 produces particles with a coercivity up to μ 0 H c = 1.63 T, while higher Ca/O ratios induce the formation of a Sm-rich TbCu 7 -type (1: 7 ) phase, which only partially transforms into the desired 1:12 phase during annealing. Persistent remnants of the 1:7 phase locally impact atomic structure, particle morphology, and coercivity. Furthermore, these findings underscore the complex interplay between synthesis parameters, resulting structures, and magnetic properties, informing the design and optimization of high-performance permanent magnets comprised of the (1:12) compound.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Isotropic nanocrystalline Sm(Fe,Co) 11.3 Ti 0.7 magnets modified with B and Zr

Rare-earth-lean Sm(Fe,Co,Ti) 12 alloys with the ThMn 12 crystal structure and less than one Ti atom per formula unit have the potential of exceptionally powerful permanent magnets, but all prior attempts to develop high coercivity in bulk alloys, especially coercivity combined with crystallographic texture, have fallen short of the expectations. This study was aimed at improvement of the currently best Sm(Fe,Co,Ti) 12 magnets prepared through melt-spinning which are inherently isotropic. Modifications of the alloys with B and Zr, already demonstrated in earlier studies to be effective separately, have been implemented simultaneously. Here, a systematic study of Sm 1.1-x (Fe,Co) 11.3-y Ti 0.7 B y alloys melt-spun at a tangential speed of 50 m/s and annealed at 600–950 °C allowed for monitoring the continuous evolution of the two consecutive crystal structures, those of the TbCu 7 and ThMn 12 types. Zirconium was found to facilitate the formation of the 1:12 structure at the expense of the 1:7, whereas boron has the opposite effect, at certain concentrations completely suppressing the 1:12. When the two alloying elements are introduced simultaneously, they inhibit growth of the 1:12 crystallites at annealing temperatures higher than 800 °C, thus allowing for the development of a higher coercivity. Because of instrumental limitations, bulk magnets were prepared through a two-step process – compaction of the melt-spun ribbons at 650 °C and additional treatment at a higher temperature – and they were characterized by a reduced, 90–93%, density. Nevertheless, an isotropic Sm 0.9 Zr 0.2 (Fe,Co) 10.8 Ti 0.7 B 0.5 magnet exhibited fair values of the remanence (7.4 kG), maximum energy product (8.5 MGOe) and coercivity (5.4 kOe), as well as high Curie temperature of 525 °C and remarkably small temperature coefficient of the coercivity, -0.25%/°C.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Effect of alloying with Sc, Nb and Zr on reduction-diffusion synthesis of magnetically hard Sm(Fe,Co,Ti) 12 -based monocrystalline powders

Powders of Sm(Fe,Co) 11.2 Ti 0.8 alloys modified with Sc, Nb and Zr, as well as with additional Ti were prepared by reducing mechanically activated raw oxides with Ca metal in the furnace preheated to 990–1250 °C. Expansion of the crystal lattice upon introduction of Nb or additional Ti implies that atoms of these elements replace the smaller Fe atoms in the tetragonal ThMn 12 -type structure. On the other hand, contraction of the lattice upon introduction of Sc or Zr was smaller than what was expected for replacement of the Sm atoms, which suggests that the Sc and Zr atoms replace both the Sm and Fe atoms. Washing away the reduction byproducts expands the crystal lattice of the 1:12 particles and increases their coercivity. The lattice expansion associated with the washing is believed to be caused by interstitial H atoms; more research, however, is needed to establish the mechanism(s) of the washing effect on the coercivity. The earlier reported development of a high coercivity in zirconium-modified monocrystalline particles achieved by increasing the reduction annealing temperature to ≈1200 °C was similarly characteristic of the particles modified with Sc (the coercivity reaches 11.5 kOe) and Nb (8.1 kOe), but not for the particles prepared with additional Ti where the maximum coercivity of 8.3 kOe develops for a lower annealing temperature. Furthermore, it is concluded that Sc, Nb and Zr modify the high-temperature phase equilibria of the Sm(Fe,Co) 11.2 Ti 0.8 alloys allowing for an effective high-temperature processing, whereas the alloy coercivity increases with the synthesis temperature through a different, still unknown mechanism which may involve suppression of the defects specific to the 1:12 crystals.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Bulk magnetic hardening in Sm(Fe,V) 12 alloys

Cast Sm-Fe-V magnets with the tetragonal crystal structure of the ThMn 12 type were prepared with high coercivity through a two-step annealing at 775°C and then at 825°C. The annealing processing used allowed us for the first time to successfully produce a large amount of non-magnetic Sm-rich grain-boundary phase in Sm-Fe-V cast ingots. As a result, the sample with composition Sm 11.1 Fe 75.8 V 13.1 showed the record-high coercivity (6.66 kOe) after annealing at 775°C for 72 h and then 825°C for 2 h. Furthermore, this coercivity, achieved without the use of powder metallurgy, has nearly doubled compared to the previously reported highest value of 3.70 kOe in a cast SmFe 10 V 2 .

36 MATERIALS SCIENCE↗
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 OSTI2025

Cross sections of 147–149 Sm( 6 Li,x) reactions for the production of 149 Tb for targeted alpha therapy

Terbium-149g (t 1/2 = 4.12 h) is of particular interest for targeted alpha therapy cancer treatment due to its ability to decay via both alpha and positron emission, making it a potential theranostic nuclide. Due to many challenges facing its production, there are limited facilities worldwide that have demonstrated the ability to produce this nuclide in quantities sufficient for medical research. Since the Cyclotron Institute at Texas A&M University is a specialized accelerator facility capable of accelerating a wide variety of ions, we are investigating production pathway options. One of the major challenges facing its production is the known co-production of the excited isomeric state, 149m Tb (t 1/2 = 4.1 min). However, this state does not decay to the ground state of 149g Tb, negating any potential contribution to its yield. Due to its short-half life, the cross section for the population of this state has never been measured. After calculating several potential reaction yields using predictive models, the reactions of 147–149 Sm( 6 Li,xn) 149 Tb were identified as candidates. Lithium-6 beams of varied energies between 45-65 MeV were impinged on enriched 147 Sm, 148 Sm, and 149 Sm targets at the Cyclotron Institute at Texas A&M University, and the reaction products were measured immediately following irradiation using high-purity germanium detectors, enabling detection of both 149m Tb and 149g Tb. Cross sections for all nuclides produced in sufficient activity in these reactions were also measured and reported here. We conclude that the population of 149m Tb is much preferred over population of the ground state for these 6 Li-induced reactions, and it is necessary to explore other options for 149g Tb production.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

A series of Rb 4 Ln 2 (P 2 S 6 )(PS 4 ) 2 (Ln = La, Ce, Pr, Nd, Sm, Gd) rare earth thiophosphates with two distinct thiophosphate units [P V S 4 ] 3- and [P IV 2 S 6 ] 4-

A series of rubidium rare earth thiophosphates with the formula Rb 4 Ln 2 (P 2 S 6 )(PS 4 ) 2 (Ln = La, Ce, Pr, Nd, Sm, and Gd) were synthesized using the high temperature molten flux crystal growth method utilizing a RbBr flux. Single crystals of all title compounds, as well as phase pure powders of the La-, Ce-, and Sm-containing compositions, were obtained. Single crystals of the title compounds were characterized by single crystal and powder X-ray diffraction for structure and phase identification. Rb 4 Ln 2 (P 2 S 6 )(PS 4 ) 2 crystallizes in the monoclinic crystal system adopting the P2 1 /n space group for the large rare earths (Ln = La, Ce, Pr) and the C2/c space group for the smaller rare earths (Ln = Nd, Sm, Gd). This Rb 4 Ln 2 (P 2 S 6 )(PS 4 ) 2 series is a rare example of thiophosphates containing both tetrahedral [P V S 4 ] 3– and dimeric [P IV 2 S 6 ] 4– thiophosphate units that, in this structural family, link corrugated rare earth sulfide chains into sheets. Here, the band gaps of the materials were determined from UV–Vis data and the fluorescence spectrum of Rb 4 Ce 2 (P 2 S 6 )(PS 4 ) 2 was collected. Optical band gaps were estimated to be 2.9 and 2.4 for the Nd and Sm analogues, respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
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 OSTI2021

Microstructure and Hard Magnetic Properties of Sm 1-x Zr x (Fe,Co) 11.3-y Ti 0.7 By Ingots and Thick Melt-Spun Ribbons

Permanent magnets made from Sm(Fe,Co) 12 -based compounds are being actively pursued through nanostructuring and powder metallurgy. This study was aimed at the development of hard magnetic properties in bulk as-cast alloys and in melt-spun alloys for very low wheel speeds. Slower solidification rates and alloying with Zr promote the tetragonal ThMn 12 -type crystal structure, whereas higher solidification rates and alloying with B replace the ThMn 12 structure type with the TbCu 7 structure type. When introduced simultaneously, Zr and B dramatically reduce the alloy solidification rates required for both the refinement of the 1:12 crystallites and their replacement with the 1:7 phase. In bulk arc-melted alloys, this allowed for a microstructure of separated 1:12 crystallites 1–3 μm in size, although, because of the ferromagnetic nature of a minority phase, the coercivity of these fine-grained alloys reached only 0.73 kOe. A moderately accelerated solidification further refined the 1:12 crystallites and increased the coercivity; a Sm 0.7 Zr 0.4 (Fe,Co) 10.8 Ti 0.7 B 0.5 alloy exhibited a coercivity of 1.5 kOe and a maximum energy product of 3.4 MGOe when it was melt-spun into a 0.26-mm-thick ribbon. A more rapid solidification suppressed the 1:12 phase and after annealing at 800–850 °C, the alloys modified with Zr and B developed reasonably high coercivity and maximum energy product even when melt-spun at a wheel speed of 6 m/s. For the above-mentioned alloy, these values were 4.1 kOe and 7.8 MGOe, respectively. Further, a similarly processed very-Sm-lean Sm 0.5 Zr 0.6 (Fe,Co) 10.6 Ti 0.7 B 0.7 alloy exhibited a remanence of 8.8 kG and an energy product of 7.4 MGOe.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Assessment of Directionally Solidified Eutectic Sm–Fe(Co)–Ti Alloys as Permanent Magnet Materials

Sm–Fe–Ti and Sm–Fe0.8Co0.2–Ti alloys were prepared via arc-melting and directionally solidified on a water-cooled copper hearth. The as-solidified alloys featured cells of the Sm(Fe,Co,Ti)12–Ti(Fe,Co) 2+δ –(α-Fe) lamellar eutectic. The lamellae of Sm(Fe,Co,Ti)12 phase with a crystal structure of the ThMn12 type were less than 0.2 μm thick, and had their [001] easy-magnetization directions oriented along the temperature gradient of the solidification. The eutectic microstructure led to an increased coercivity, especially in the Co-added alloys. Below 250 °C, this coercivity was found not to vary much with temperature with a temperature coefficient of -0.18 %/°C. However, the modest absolute values, reaching only 0.7 kOe, are insufficient for utilization of the directionally solidified alloys as anisotropic permanent magnets.

36 MATERIALS SCIENCE↗