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All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

2021 Results for Avian Monitoring of Inorganic and Organic Element Concentrations in Passerine Eggs and Nestlings Collected from Technical Area 16 Burn Grounds, Technical Area 36 Minie, and Technical Area 39 Point 6 at Los Alamos National Laboratory (Rev. 2)

In 2021, non-viable avian eggs and one nestling were opportunistically collected at Los Alamos National Laboratory (LANL) near open detonation sites located at Technical Area (TA) 16 burn grounds and TA-36 Minie. Similar to previous years, nestboxes were monitored at TA-39 Point 6, however, no avian samples were available for opportunistic collection. Samples were evaluated for inorganic elements (mostly metals), dioxins, and furans. One ash-throated flycatcher (Myiarchus cinerascens) egg sample was collected from TA-16 burn grounds. One ash-throated flycatcher and one mountain bluebird (Sialia currucoides) egg sample and one deceased western bluebird (Sialia mexicana) nestling sample were collected from TA-36 Minie. Concentrations of inorganic elements observed in this study were compared with the regional statistical reference level (RSRL) which is the upper-level bounds of background concentrations (mean + three standard deviations = 99% confidence interval). Several inorganic elements were not detected in avian eggs. Most inorganic elements detected were below the RSRL and all were the lowest observable adverse effect level (LOAEL), when available. The nestling collected from TA-36 did not contain detectable concentrations of dioxin or furan congeners. These data suggest that inorganic and organic element concentrations in eggs and nestlings are not of ecological concern. More data are needed to make a robust assessment and to evaluate trends over time.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

A Dynamically Distinct Stellar Population in the Leading Arm of the Sagittarius Stream

We present a chemical and dynamical analysis of the leading arm (LA) and trailing arm (TA) of the Sagittarius (Sgr) stream, as well as for the Sgr dwarf galaxy core (SC), using red giant branch, main-sequence, and RR Lyrae stars from large spectroscopic survey data. The different chemical properties among the LA, TA, and SC generally agree with recent studies and can be understood by a radial metallicity gradient established in the progenitor of the Sgr dwarf, followed by preferential stellar stripping from the outer part of the Sgr progenitor. One striking finding is a relatively larger fraction of low-eccentricity stars (e < 0.4) in the LA than in the TA and SC. The TA and SC exhibit very similar distributions. Considering that a tidal tail stripped off from a dwarf galaxy maintains the orbital properties of its progenitor, we expect that the e-distribution of the LA should be similar to that of the TA and SC. Thus, the disparate behavior of the e-distribution of the LA is of particular interest. Following the analysis of Vasiliev et al., we attempt to explain the different e-distribution by introducing a time-dependent perturbation of the Milky Way by the Large Magellanic Cloud's (LMC) gravitational pull, resulting in substantial evolution of the angular momentum of the LA stars to produce the low-e stars. In addition, we confirm from RR Lyrae stars with high eccentricity (e > 0.6) that the TA stars farther away from the SC are also affected by disturbances from the LMC.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Tantalum alloy–based resonators for quantum information systems

Utilizing tantalum (Ta) in superconducting circuits has led to significant improvements, such as high qubit lifetime (T 1 ) and quality factors in both qubits and resonators, suggesting that material optimization plays an important role in the development of superconducting circuits. Thus we here explore superconducting gap engineering in Ta-based devices as a powerful strategy for expanding the range of suitable host materials. By alloying 20 atomic percent (at.%) hafnium into Ta thin films, we achieve a superconducting transition temperature (T c ) of 6.09 K as observed in direct current (DC) transport measurements, reflecting an increase in the superconducting gap. We systematically vary deposition conditions to control film orientation and transport properties of Ta-Hf alloy thin films. We then confirm the enhancement in T c via microwave measurements at millikelvin temperatures. We verify the ~40 increase in T c relative to bare Ta devices, while the loss contributions from two-level systems and quasi-particles remain unchanged in the low temperature regime. These findings emphasize the promise of material engineering in superconducting circuits and point to many potential material candidates for further exploration.

Ta-Hf alloy thin films↗
DOE OSTI2020

Materials Data on Li2LaTa2O7 by Materials Project

Li2LaTa2O7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Li–O bond lengths are 2.10 Å. La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with four equivalent LaO12 cuboctahedra, faces with four equivalent LaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.69 Å) and four longer (2.83 Å) La–O bond lengths. Ta+4.50+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five equivalent TaO6 octahedra and faces with four equivalent LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–17°. There are a spread of Ta–O bond distances ranging from 1.90–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Li1+ and one Ta+4.50+ atom to form a mixture of distorted edge and corner-sharing OLi4Ta trigonal bipyramids. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent La3+ and two equivalent Ta+4.50+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent La3+ and two equivalent Ta+4.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaSiRh by Materials Project

TaRhSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 11-coordinate geometry to six equivalent Rh and five equivalent Si atoms. There are a spread of Ta–Rh bond distances ranging from 2.91–3.00 Å. There are three shorter (2.68 Å) and two longer (2.74 Å) Ta–Si bond lengths. Rh is bonded in a 4-coordinate geometry to six equivalent Ta and four equivalent Si atoms. There are a spread of Rh–Si bond distances ranging from 2.41–2.47 Å. Si is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaGaNi2 by Materials Project

TaNi2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ta is bonded in a body-centered cubic geometry to eight equivalent Ni and six equivalent Ga atoms. All Ta–Ni bond lengths are 2.59 Å. All Ta–Ga bond lengths are 2.99 Å. Ni is bonded in a body-centered cubic geometry to four equivalent Ta and four equivalent Ga atoms. All Ni–Ga bond lengths are 2.59 Å. Ga is bonded in a distorted body-centered cubic geometry to six equivalent Ta and eight equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaSiIr by Materials Project

TaIrSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 11-coordinate geometry to six equivalent Ir and five equivalent Si atoms. There are a spread of Ta–Ir bond distances ranging from 2.92–2.99 Å. There are a spread of Ta–Si bond distances ranging from 2.67–2.77 Å. Ir is bonded in a 4-coordinate geometry to six equivalent Ta and four equivalent Si atoms. There are a spread of Ir–Si bond distances ranging from 2.41–2.47 Å. Si is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Ir atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaFeP by Materials Project

TaFeP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 5-coordinate geometry to six equivalent Fe and five equivalent P atoms. There are a spread of Ta–Fe bond distances ranging from 2.74–2.86 Å. There are one shorter (2.58 Å) and four longer (2.60 Å) Ta–P bond lengths. Fe is bonded in a 4-coordinate geometry to six equivalent Ta and four equivalent P atoms. There are a spread of Fe–P bond distances ranging from 2.25–2.36 Å. P is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2InC by Materials Project

Ta2InC is H-Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ta is bonded in a 3-coordinate geometry to three equivalent In and three equivalent C atoms. All Ta–In bond lengths are 3.04 Å. All Ta–C bond lengths are 2.19 Å. In is bonded to six equivalent Ta and six equivalent In atoms to form distorted InTa6In6 cuboctahedra that share corners with six equivalent InTa6In6 cuboctahedra, corners with six equivalent CTa6 octahedra, edges with six equivalent InTa6In6 cuboctahedra, edges with six equivalent CTa6 octahedra, and faces with six equivalent InTa6In6 cuboctahedra. The corner-sharing octahedral tilt angles are 20°. All In–In bond lengths are 3.17 Å. C is bonded to six equivalent Ta atoms to form CTa6 octahedra that share corners with six equivalent InTa6In6 cuboctahedra, edges with six equivalent InTa6In6 cuboctahedra, and edges with six equivalent CTa6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta4FeP by Materials Project

Ta4FeP is Khatyrkite-derived structured and crystallizes in the tetragonal P4/mcc space group. The structure is three-dimensional. Ta is bonded in a 4-coordinate geometry to two equivalent Fe and two equivalent P atoms. Both Ta–Fe bond lengths are 2.57 Å. Both Ta–P bond lengths are 2.66 Å. Fe is bonded in a 10-coordinate geometry to eight equivalent Ta and two equivalent Fe atoms. Both Fe–Fe bond lengths are 2.55 Å. P is bonded in a 10-coordinate geometry to eight equivalent Ta and two equivalent P atoms. Both P–P bond lengths are 2.55 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaNiGe by Materials Project

TaNiGe crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 5-coordinate geometry to six equivalent Ni and five equivalent Ge atoms. There are a spread of Ta–Ni bond distances ranging from 2.86–2.99 Å. There are a spread of Ta–Ge bond distances ranging from 2.69–2.72 Å. Ni is bonded in a 4-coordinate geometry to six equivalent Ta and four equivalent Ge atoms. There are a spread of Ni–Ge bond distances ranging from 2.35–2.41 Å. Ge is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaClF8 by Materials Project

TaClF8 crystallizes in the orthorhombic Pcca space group. The structure is one-dimensional and consists of two TaClF8 ribbons oriented in the (0, 1, 0) direction. Ta is bonded in an octahedral geometry to six F atoms. There are a spread of Ta–F bond distances ranging from 1.88–2.01 Å. Cl is bonded in a square co-planar geometry to four F atoms. There is two shorter (1.63 Å) and two longer (2.18 Å) Cl–F bond length. There are four inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Ta atom. In the second F site, F is bonded in a single-bond geometry to one Cl atom. In the third F site, F is bonded in a single-bond geometry to one Ta atom. In the fourth F site, F is bonded in a bent 150 degrees geometry to one Ta and one Cl atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaGaCo2 by Materials Project

TaCo2Ga is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ta is bonded in a distorted body-centered cubic geometry to eight equivalent Co and six equivalent Ga atoms. All Ta–Co bond lengths are 2.58 Å. All Ta–Ga bond lengths are 2.98 Å. Co is bonded in a body-centered cubic geometry to four equivalent Ta and four equivalent Ga atoms. All Co–Ga bond lengths are 2.58 Å. Ga is bonded in a distorted body-centered cubic geometry to six equivalent Ta and eight equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaSbRu by Materials Project

TaRuSb is half-Heusler structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Ta is bonded to four equivalent Ru and six equivalent Sb atoms to form a mixture of distorted face and corner-sharing TaSb6Ru4 tetrahedra. All Ta–Ru bond lengths are 2.68 Å. All Ta–Sb bond lengths are 3.10 Å. Ru is bonded in a body-centered cubic geometry to four equivalent Ta and four equivalent Sb atoms. All Ru–Sb bond lengths are 2.68 Å. Sb is bonded in a 10-coordinate geometry to six equivalent Ta and four equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaCoSb by Materials Project

TaCoSb is half-Heusler structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Ta is bonded in a 4-coordinate geometry to four equivalent Co and six equivalent Sb atoms. All Ta–Co bond lengths are 2.58 Å. All Ta–Sb bond lengths are 2.98 Å. Co is bonded in a body-centered cubic geometry to four equivalent Ta and four equivalent Sb atoms. All Co–Sb bond lengths are 2.58 Å. Sb is bonded in a 10-coordinate geometry to six equivalent Ta and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta3SiNi2 by Materials Project

Ta3Ni2Si crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ta is bonded in a 6-coordinate geometry to four equivalent Ni and two equivalent Si atoms. There are two shorter (2.67 Å) and two longer (2.74 Å) Ta–Ni bond lengths. Both Ta–Si bond lengths are 2.76 Å. Ni is bonded in a 12-coordinate geometry to six equivalent Ta, three equivalent Ni, and three equivalent Si atoms. All Ni–Ni bond lengths are 2.63 Å. All Ni–Si bond lengths are 2.42 Å. Si is bonded to six equivalent Ta and six equivalent Ni atoms to form face-sharing SiTa6Ni6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2Zn4O9 by Materials Project

Zn4Ta2O9 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with six ZnO4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Ta–O bond distances ranging from 1.96–2.03 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two TaO6 octahedra, corners with three ZnO4 tetrahedra, a cornercorner with one ZnO5 trigonal bipyramid, and edges with two TaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–38°. There are a spread of Ta–O bond distances ranging from 1.91–2.14 Å. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four ZnO4 tetrahedra, and edges with two equivalent ZnO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 34°. There are four shorter (2.00 Å) and two longer (2.01 Å) Ta–O bond lengths. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five ZnO4 tetrahedra, corners with two equivalent ZnO5 trigonal bipyramids, and an edgeedge with one TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.90–2.26 Å. In the fifth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six ZnO4 tetrahedra, a cornercorner with one ZnO5 trigonal bipyramid, and an edgeedge with one TaO6 octahedra. There are a spread of Ta–O bond distances ranging from 1.92–2.19 Å. There are eight inequivalent Zn2+ sites. In the first Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with six TaO6 octahedra, a cornercorner with one ZnO4 tetrahedra, a cornercorner with one ZnO5 trigonal bipyramid, and an edgeedge with one ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–64°. There are a spread of Zn–O bond distances ranging from 1.93–2.11 Å. In the second Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with four TaO6 octahedra, corners with two ZnO4 tetrahedra, and a cornercorner with one ZnO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 49–66°. There are a spread of Zn–O bond distances ranging from 1.96–2.09 Å. In the third Zn2+ site, Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with five TaO6 octahedra, a cornercorner with one ZnO4 tetrahedra, and an edgeedge with one ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 34–65°. There are a spread of Zn–O bond distances ranging from 1.95–2.02 Å. In the fourth Zn2+ site, Zn2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Zn–O bond distances ranging from 1.93–2.11 Å. In the fifth Zn2+ site, Zn2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Zn–O bond distances ranging from 2.00–2.25 Å. In the sixth Zn2+ site, Zn2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Zn–O bond distances ranging from 1.95–2.06 Å. In the seventh Zn2+ site, Zn2+ is bonded to five O2- atoms to form distorted ZnO5 trigonal bipyramids that share corners with four TaO6 octahedra, corners with two ZnO4 tetrahedra, an edgeedge with one TaO6 octahedra, and an edgeedge with one ZnO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 40–56°. There are a spread of Zn–O bond distances ranging from 1.99–2.26 Å. In the eighth Zn2+ site, Zn2+ is bonded to four O2- atoms to form distorted ZnO4 tetrahedra that share corners with four TaO6 octahedra, corners with two ZnO4 tetrahedra, and an edgeedge with one ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–65°. There are a spread of Zn–O bond distances ranging from 1.95–2.03 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Zn2+ atoms. In the third O2- site, O2- is bonded to two Ta5+ and two equivalent Zn2+ atoms to form distorted OTa2Zn2 tetrahedra that share corners with two equivalent OTaZn3 tetrahedra, a cornercorner with one OTa2Zn2 trigonal pyramid, and an edgeedge with one OTa2Zn2 tetrahedra. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to two Ta5+ and one Zn2+ atom. In the fifth O2- site, O2- is bonded to two Ta5+ and two equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing OTa2Zn2 trigonal pyramids. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+ and two Zn2+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ta5+ and one Zn2+ atom. In the eighth O2- site, O2- is bonded to one Ta5+ and three Zn2+ atoms to form a mixture of distorted edge and corner-sharing OTaZn3 tetrahedra. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Zn2+ atoms. In the tenth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ta5+ and two equivalent Zn2+ atoms. In the eleventh O2- site, O2- is bonded in a trigonal planar geometry to one Ta5+ and two Zn2+ atoms. In the twelfth O2- site, O2- is bonded in a trigonal planar geometry to two Ta5+ and one Zn2+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two equivalent Zn2+ atoms. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Zn2+ atoms. In the fifteenth O2- site, O2- is bonded to one Ta5+ and three Zn2+ atoms to form corner-sharing OTaZn3 tetrahedra. In the sixteenth O2- site, O2- is bonded in a trigonal planar geometry to one Ta5+ and two Zn2+ atoms. In the seventeenth O2- site, O2- is bonded to one Ta5+ and three Zn2+ atoms to form a mixture of distorted edge and corner-sharing OTaZn3 tetrahedra. In the eighteenth O2- site, O2- is bonded in a trigonal planar geometry to one Ta5+ and two Zn2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2NbRh by Materials Project

Ta2NbRh is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ta is bonded in a distorted body-centered cubic geometry to four equivalent Nb and four equivalent Rh atoms. All Ta–Nb bond lengths are 2.81 Å. All Ta–Rh bond lengths are 2.81 Å. Nb is bonded in a 8-coordinate geometry to eight equivalent Ta and six equivalent Rh atoms. All Nb–Rh bond lengths are 3.24 Å. Rh is bonded in a distorted body-centered cubic geometry to eight equivalent Ta and six equivalent Nb atoms.

36 MATERIALS SCIENCE↗