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DOE OSTI2020

Materials Data on Sm(Fe5Si)2 by Materials Project

Sm(Fe5Si)2 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. Sm is bonded in a 12-coordinate geometry to sixteen Fe and four equivalent Si atoms. There are a spread of Sm–Fe bond distances ranging from 2.99–3.19 Å. All Sm–Si bond lengths are 3.15 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded in a 10-coordinate geometry to one Sm, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.33–2.94 Å. Both Fe–Si bond lengths are 2.55 Å. In the second Fe site, Fe is bonded to two equivalent Sm and ten Fe atoms to form FeSm2Fe10 cuboctahedra that share corners with four equivalent SiSm2Fe8Si2 cuboctahedra, corners with fourteen FeSm2Fe10 cuboctahedra, edges with four equivalent FeSm2Fe8Si2 cuboctahedra, edges with four equivalent SiSm2Fe8Si2 cuboctahedra, faces with four equivalent SiSm2Fe8Si2 cuboctahedra, and faces with ten FeSm2Fe10 cuboctahedra. There are two shorter (2.40 Å) and four longer (2.41 Å) Fe–Fe bond lengths. In the third Fe site, Fe is bonded to two equivalent Sm, eight Fe, and two equivalent Si atoms to form distorted FeSm2Fe8Si2 cuboctahedra that share corners with four equivalent SiSm2Fe8Si2 cuboctahedra, corners with fourteen FeSm2Fe10 cuboctahedra, edges with two equivalent SiSm2Fe8Si2 cuboctahedra, edges with five FeSm2Fe10 cuboctahedra, faces with four equivalent SiSm2Fe8Si2 cuboctahedra, and faces with eleven FeSm2Fe10 cuboctahedra. There are one shorter (2.65 Å) and one longer (2.66 Å) Fe–Fe bond lengths. Both Fe–Si bond lengths are 2.40 Å. Si is bonded to two equivalent Sm, eight Fe, and two equivalent Si atoms to form distorted SiSm2Fe8Si2 cuboctahedra that share corners with six equivalent SiSm2Fe8Si2 cuboctahedra, corners with twelve FeSm2Fe10 cuboctahedra, edges with eight FeSm2Fe10 cuboctahedra, faces with two equivalent SiSm2Fe8Si2 cuboctahedra, and faces with twelve FeSm2Fe10 cuboctahedra. Both Si–Si bond lengths are 2.40 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(AlAu)2 by Materials Project

Sm(AuAl)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight Au and eight Al atoms. There are four shorter (3.38 Å) and four longer (3.39 Å) Sm–Au bond lengths. There are four shorter (3.37 Å) and four longer (3.43 Å) Sm–Al bond lengths. There are two inequivalent Au sites. In the first Au site, Au is bonded to four equivalent Sm and four equivalent Al atoms to form distorted AuSm4Al4 tetrahedra that share corners with twelve equivalent AlSm4Au4 tetrahedra, edges with two equivalent AlSm4Au4 tetrahedra, edges with four equivalent AuSm4Al4 tetrahedra, and faces with four equivalent AuSm4Al4 tetrahedra. All Au–Al bond lengths are 2.60 Å. In the second Au site, Au is bonded in a 5-coordinate geometry to four equivalent Sm and five Al atoms. There are one shorter (2.49 Å) and four longer (2.59 Å) Au–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Sm and four equivalent Au atoms to form distorted AlSm4Au4 tetrahedra that share corners with twelve equivalent AuSm4Al4 tetrahedra, edges with two equivalent AuSm4Al4 tetrahedra, edges with four equivalent AlSm4Au4 tetrahedra, and faces with four equivalent AlSm4Au4 tetrahedra. In the second Al site, Al is bonded in a 5-coordinate geometry to four equivalent Sm and five Au atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Mechanically robust high magnetic-performance Sm-Co sintered magnets through microstructure engineering

Samarium-cobalt (Sm-Co) sintered magnets have high magnetic energy densities, great resistance to demagnetization and corrosion, and excellent thermal stability in a wide temperature range (–50–550 °C). However, the utilization of these magnets is restricted by their brittleness. Based on micromechanical and the Zener pinning model, Sm-Co sintered magnets with improved mechanical properties have been designed and fabricated via microstructure engineering. A small amount of fine Sm 2 O 3 particulates (0–3 wt%) has been incorporated into Sm 2 (CoFeCuZr) 17 sintered magnets to refine the grain size by up to approximately 50% (from 45 to 22 µm) and narrow the grain size distribution. Doping with 3 wt% Sm 2 O 3 increased the flexural strength by 62% while maintaining magnetic performance. Both grain-refined unimodal microstructure and heterogeneous laminated coarse/fine grain microstructure were formed by strategically designed assemblies of Sm 2 O 3 -added Sm-Co powder feedstock mixtures. The technology is compatible with existing magnet manufacturing processes. Numerical micromechanics simulation indicates that the fracture is dominated by intragranular mode. The mechanical strength is mainly enhanced by the additive-induced grain refinement, while the small amount of Sm 2 O 3 addition has a small direct positive contribution. Finally, these magnets will be more cost-effective, efficient, and robust for various functional applications.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Potential high-performance magnet materials: Co- and Al-alloyed Sm 2 Fe 17

Sm 2 Fe 17 has long been known as a potential high-performance magnet whose deficiencies—planar anisotropy and lower-than-optimal T c —can be remedied by nitrogen addition, but which presents synthesis difficulties. In this work, we apply first-principles calculations to search for alternative low-cost, high-performance permanent magnets in this family, by exploring simultaneous Fe and Al substitution. Specifically, the goal is to improve properties of Sm 2 Fe 14 Al 3 easy-plane magnet at the stoichiometric composition. Density functional theory calculations were executed for three series of compounds, i.e., Sm 2 (Fe 1-x Co x ) 14 Al 3 , Sm 2 (Fe 1-x Co x ) 15 Al 2 , and Sm 2 (Fe 1-x Cox) 16 Al. We find that substitution of Fe with 12–18 of Co in % Sm 2 Fe 14 Al 3 modifies the magnetic anisotropy type from easy plane to easy axis with a substantial anisotropy of 7.1 MJ/m 3 . We also demonstrate that the largest part of magnetic anisotropy is introduced by 4f Sm atom electrons. Thus the rotation of magnetic moment orientation from $\langle$$1\bar10$$\rangle$ to $\langle$111$\rangle$ is followed by an increase of the occupied 4f state number and, as a result, the orbital part of the magnetic moment of one of the Sm atoms. This increase of the occupied 4f state number at an energy ~ -4.3 eV results in a significant reduction of band structure energy. The substitution of Fe by Co does not significantly reduce the magnetization of the compound and keeps it slightly above 1 T. This combination of magnetic anisotropy and magnetization makes the compound a promising candidate for a permanent magnet.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(Al2Cu)4 by Materials Project

Sm(CuAl2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 12-coordinate geometry to eight equivalent Cu and twelve Al atoms. All Sm–Cu bond lengths are 3.38 Å. There are four shorter (3.08 Å) and eight longer (3.23 Å) Sm–Al bond lengths. Cu is bonded to two equivalent Sm, two equivalent Cu, and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing CuSm2Al8Cu2 cuboctahedra. Both Cu–Cu bond lengths are 2.58 Å. There are four shorter (2.57 Å) and four longer (2.70 Å) Cu–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Sm, four equivalent Cu, and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.67–2.82 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Sm, four equivalent Cu, and six Al atoms. Both Al–Al bond lengths are 2.75 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(Sn3Ru2)2 by Materials Project

Sm(Ru2Sn3)2 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. Sm is bonded in a 12-coordinate geometry to four equivalent Ru and twelve Sn atoms. All Sm–Ru bond lengths are 3.30 Å. There are a spread of Sm–Sn bond distances ranging from 3.39–3.77 Å. Ru is bonded in a 7-coordinate geometry to one Sm, two equivalent Ru, and six Sn atoms. Both Ru–Ru bond lengths are 2.85 Å. There are a spread of Ru–Sn bond distances ranging from 2.60–2.80 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 6-coordinate geometry to two equivalent Sm and four equivalent Ru atoms. In the second Sn site, Sn is bonded in a 5-coordinate geometry to two equivalent Sm and four equivalent Ru atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(MnAl2)4 by Materials Project

Sm(MnAl2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 4-coordinate geometry to eight equivalent Mn and twelve Al atoms. All Sm–Mn bond lengths are 3.39 Å. There are four shorter (3.00 Å) and eight longer (3.28 Å) Sm–Al bond lengths. Mn is bonded to two equivalent Sm, two equivalent Mn, and eight Al atoms to form distorted MnSm2Mn2Al8 cuboctahedra that share corners with eight equivalent AlSm2Mn4Al6 cuboctahedra, corners with ten equivalent MnSm2Mn2Al8 cuboctahedra, edges with four equivalent MnSm2Mn2Al8 cuboctahedra, edges with four equivalent AlSm2Mn4Al6 cuboctahedra, faces with six equivalent MnSm2Mn2Al8 cuboctahedra, and faces with eight equivalent AlSm2Mn4Al6 cuboctahedra. Both Mn–Mn bond lengths are 2.59 Å. There are four shorter (2.57 Å) and four longer (2.68 Å) Mn–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Sm, four equivalent Mn, and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.77–2.85 Å. In the second Al site, Al is bonded to two equivalent Sm, four equivalent Mn, and six Al atoms to form distorted AlSm2Mn4Al6 cuboctahedra that share corners with eight equivalent MnSm2Mn2Al8 cuboctahedra, corners with ten equivalent AlSm2Mn4Al6 cuboctahedra, edges with three equivalent AlSm2Mn4Al6 cuboctahedra, edges with four equivalent MnSm2Mn2Al8 cuboctahedra, faces with seven equivalent AlSm2Mn4Al6 cuboctahedra, and faces with eight equivalent MnSm2Mn2Al8 cuboctahedra. Both Al–Al bond lengths are 2.84 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(PIr)2 by Materials Project

SmIr2P2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight Ir and eight P atoms. There are four shorter (3.19 Å) and four longer (3.24 Å) Sm–Ir bond lengths. There are four shorter (3.12 Å) and four longer (3.15 Å) Sm–P bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded to four equivalent Sm and four equivalent P atoms to form a mixture of distorted edge and face-sharing IrSm4P4 cuboctahedra. All Ir–P bond lengths are 2.48 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Sm and five P atoms. There are four shorter (2.35 Å) and one longer (2.37 Å) Ir–P bond lengths. There are two inequivalent P sites. In the first P site, P is bonded in a 8-coordinate geometry to four equivalent Sm and four equivalent Ir atoms. In the second P site, P is bonded in a 9-coordinate geometry to four equivalent Sm and five Ir atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2021

New loading method for high precision Sm isotope analysis of nuclear materials using thermal ionization mass spectrometry

This work demonstrates an analytical protocol for high precision Sm isotope analysis by thermal ionization mass spectrometry (TIMS) using a Pt activator. Here, the method permits precise measurements of small aliquots (1–20 ng) of Sm on single Re filament using a modified static-total evaporation technique. This study represents the first attempt to use such protocols for Sm isotope analyses while reducing the loading size of Sm for TIMS. The method could potentially be deployed to study geological, meteorites and lunar samples containing low Sm concentrations, to monitor neutron irradiation exposure based on 149,150 Sm, or to measure Sm isotopic composition in other types of nuclear samples.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

DOE OSTI2022

Mechanically Robust High Magnetic Performance Sm-Co Sintered Magnets (Final Report)

Samarium-cobalt based permanent magnets (SmCo 5 and Sm 2 Co 17 ) have excellent magnetic properties, good corrosion resistance, and long-term thermal stability. Sm-Co sintered magnets have been widely used in electric machines, telecommunication, biomedical devices, and magnetic sensors. They are the most preferred magnets for high-temperature applications (200 - 550 °C). However, Sm-Co sintered magnets are brittle. They cannot be used for applications subjected to high stress, vibration, or mechanical shock. Sm-Co sintered magnets are prone to chipping, and fracture in the course of block magnet manufacturing, part machining, assembly, and operation. The brittleness leads to a magnet production loss of up to 20-30% in volume and imposes limitations on part size and shape. Developing mechanically robust high-performance Sm-Co sintered magnets is of great scientific and technical significance. This project is in response to the current market need for mechanically robust high magnetic performance Sm-Co sintered magnets and their novel manufacturing processes. The project will focus on scaling-up, validation, and technology maturation study of the mechanically tough high magnetic performance Sm-Co magnets developed by Ames Laboratory at a lab-scale with the collaboration of the industry partner Electron Energy Corporation (EEC).

36 MATERIALS SCIENCE↗

NASA NTRS1995

Neutron-capture Cl-36, Ca-41, Ar-36, and Sm-150 in large chondrites: Evidence for high fluences of thermalized neutrons

We have measured significant concentrations of Cl-36, Ca-41, Ar-36 from decay of Cl-36, and Sm-150 produced from the capture of thermalized neutrons in the large Chico L6 chondrite. Activities of Cl-36 and Ca-41, corrected for a high-energy spallogenic component and a terrestrial age of approximately 50 ka, give average neutron-capture production rates of 208 atoms/min/g-Cl and 1525 atoms/min/kg-Ca, which correspond to thermal neutron (n) fluxes of 6.2 n/sq cm/s and 4.3 n/sq cm/s, respectively. If sustained for the approximately 65 Ma single-stage, cosmic ray exposure age of Chico, these values correspond to thermal neutron fluences of approximately 1.3 x 10(exp 16) and 0.8 x 10(exp 16) n/sq cm for Cl-36 and Ca-41, respectively. Stepwise temperature extraction of Ar in Chico impact melt shows Ar-36/Ar-38 ratios as large as approximately 9. The correlation of high Ar-36/Ar-38 with high Cl/Ca phases in neutron-irradiated Chico indicates that the excess Ar-36 above that expected from spallation is due to decay of neutron-produced Cl-36. Excess Ar-36 in Chico requires a thermal neutron fluence of 0.9-1.7 x 10(exp 16) n/sq cm. Decreases in Sm-149/Sm-152 due to neutron-capture by Sm-149 correlate with increases in Sm-150/Sm-152 for three samples of Chico, and one of the Torino H-chondrite. The 0.08% decrease in Sm-149 shown by Chico corresponds to a neutron fluence of 1.23 x 10(exp 16) n/sq cm. This fluence derived from Sm considers capture of epithermal neutrons and effects of chemical composition on the neutron energy distribution. Excess Ar-36 identified in the Arapahoe, Bruderheim, and Torino chondrites and the Shallowater aubrite suggest exposure to neutron fluences of approximately 0.2-0.2 x 10(exp 16) n/sq cm. Depletion of Sm-149 in Torino and the LEW86010 angrite suggest neutron fluences of 0.8 x 10(exp 16) n/sq cm and 0.25 x 10(exp 16) n/sq cm, respectively. Neutron fluences of approximately 10(exp 16) n/sq cm in Chico are almost as large as those previously observed for some lunar soils. Consideration of exposure ages suggests that the neutron flux in Chico may have been greater than that in many lunar soils.

Bogard, D. D.↗

NASA NTRS2007

Sm-Nd Isotopic Systematics of Troctolite 76335

A study of the Sm-Nd isotopic systematics of lunar Mg-suite troctolite 76335 was undertaken to further establish the early chronology of lunar magmatism. Because the Rb-Sr isotopic systematics of similar sample 76535 yielded an age of 4570 +/- 70 Ma [2, lambda = 1.402 x 10(exp -11)], 76335 was expected to yield an old age. In contrast, the Sm-Nd and K-Ar ages of 76535 indicate that the sample is approximately 4260 Ma old, one of the youngest ages obtained for a Mg-suite rock. This study establishes the age of 76335 and discusses the constraints placed on its petrogenesis by its Sm-Nd isotope systematics. The Sm-Nd isotopic system of lunar Mg-suite troctolite 76335 indicates an age of 4278 +/- 60 Ma with an initial epsilon (sup 143)(sub Nd) value of 0.06 +/- 0.39. These values are consistent with the Sm-Nd isotopic systematics of similar sample 76535. Thus, it appears that a robust Sm-Nd age can be determined from a highly brecciated lunar sample. The Sm-Nd isotopic systematics of troctolites 76335 and 76535 appear to be different from those dominating the Mg-suite norites and KREEP basalts. Further analysis of the Mg-suite must be completed to reveal the isotopic relationships of these early lunar rocks.

Edmunson, J.↗

NASA NTRS2011

Sm-Nd and Initial Sr-87/Sr-86 Isotopic Systematics of Asuka 881394 and Cumulate Eucrites Yamato 980318/433 Compared

The Asuka 881394 achondrite contains fossil Al-26 and Mn-53 and has a Pb-206/Pb-207 age of 4566.5 +/- 0.2 Ma, the oldest for an achondrite. Recent re-investigation of A881394 yielded revised initial Sm-146/Sm-144 = (9.1 +/- 1.4) x 10(exp -3), a Sm-147-Nd-143 age of 4525 +/- 58 Ma, a Rb-87-Sr-87 age of 4490 +/- 130 Ma, and initial Sr-87/Sr-86 = 0.698991 +/- 19, respectively. The relatively large uncertainties in the Sm-Nd and Rb-Sr ages are due to disturbances of the isotopic systematics of tridymite and other minor phases. A preliminary value for the Sm-147-Nd-143 age of the Yamato 980318 cumulate eucrite of 4560 +/- 150 Ma was refined in later work to 4567 +/- 24 Ma as reported orally at LPSC 35. Similarly, a preliminary value for Sm-146/Sm-144 = (7.7 +/- 1.2) x 10 (exp -3) was refined to (6.0 +/- 0.3) x 10(exp -3). For Yamato 980433, a Sm-147-Nd-143 age of 4542 +/-42 Ma and Sm-146/Sm-144 = (5.7 +/- 0.5) x 10(exp -3) has been reported. Because these two cumulate eucrites are paired, we consider them to represent one igneous rock and present their combined isotopic data here.

Nyquist, L. E.↗

DOE OSTI2020

Materials Data on Sm(GaPd)2 by Materials Project

Sm(PdGa)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ga atoms. All Sm–Pd bond lengths are 3.38 Å. All Sm–Ga bond lengths are 3.28 Å. Pd is bonded to four equivalent Sm and four equivalent Ga atoms to form a mixture of distorted edge, face, and corner-sharing PdSm4Ga4 tetrahedra. All Pd–Ga bond lengths are 2.53 Å. Ga is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Pd, and one Ga atom. The Ga–Ga bond length is 2.55 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(GePd)2 by Materials Project

Sm(PdGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All Sm–Pd bond lengths are 3.34 Å. All Sm–Ge bond lengths are 3.30 Å. Pd is bonded in a 4-coordinate geometry to four equivalent Sm and four equivalent Ge atoms. All Pd–Ge bond lengths are 2.53 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(GeRh)2 by Materials Project

Sm(RhGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Ge atoms. All Sm–Rh bond lengths are 3.35 Å. All Sm–Ge bond lengths are 3.22 Å. Rh is bonded to four equivalent Sm and four equivalent Ge atoms to form a mixture of distorted corner, edge, and face-sharing RhSm4Ge4 tetrahedra. All Rh–Ge bond lengths are 2.47 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Rh, and one Ge atom. The Ge–Ge bond length is 2.58 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(NiGe)2 by Materials Project

Sm(NiGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Ge atoms. All Sm–Ni bond lengths are 3.21 Å. All Sm–Ge bond lengths are 3.18 Å. Ni is bonded in a 4-coordinate geometry to four equivalent Sm and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.37 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Sm, four equivalent Ni, and one Ge atom. The Ge–Ge bond length is 2.57 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sm(AlZn)2 by Materials Project

Sm(ZnAl)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 8-coordinate geometry to eight equivalent Zn and eight equivalent Al atoms. All Sm–Zn bond lengths are 3.19 Å. All Sm–Al bond lengths are 3.45 Å. Zn is bonded in a 9-coordinate geometry to four equivalent Sm, one Zn, and four equivalent Al atoms. The Zn–Zn bond length is 2.43 Å. All Zn–Al bond lengths are 2.59 Å. Al is bonded to four equivalent Sm, four equivalent Zn, and four equivalent Al atoms to form a mixture of distorted edge, face, and corner-sharing AlSm4Al4Zn4 cuboctahedra. All Al–Al bond lengths are 2.95 Å.

36 MATERIALS SCIENCE↗