Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Sr(HO)2”

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.

17 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Sr(HO)2 by Materials Project

Sr(OH)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 7-coordinate geometry to one H1+ and six O2- atoms. The Sr–H bond length is 2.54 Å. There are a spread of Sr–O bond distances ranging from 2.54–2.66 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Sr2+ and one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three equivalent Sr2+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three equivalent Sr2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(HoS2)2 by Materials Project

Sr(HoS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.09–3.29 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing HoS6 octahedra. The corner-sharing octahedra tilt angles range from 48–63°. There are a spread of Ho–S bond distances ranging from 2.70–2.76 Å. In the second Ho3+ site, Ho3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing HoS6 octahedra. The corner-sharing octahedra tilt angles range from 48–63°. There are a spread of Ho–S bond distances ranging from 2.68–2.76 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Sr2+ and three Ho3+ atoms. In the second S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Ho3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Ho3 square pyramids. In the third S2- site, S2- is bonded to two equivalent Sr2+ and three Ho3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Ho3 trigonal bipyramids. In the fourth S2- site, S2- is bonded to two equivalent Sr2+ and three equivalent Ho3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Ho3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2HoCu3(PbO4)2 by Materials Project

Pb2Sr2HoCu3O8 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.60–2.83 Å. Ho3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ho–O bond lengths are 2.40 Å. There are two inequivalent Cu+1.67+ sites. In the first Cu+1.67+ site, Cu+1.67+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.86 Å. In the second Cu+1.67+ site, Cu+1.67+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four equivalent CuO5 square pyramids. There are four shorter (1.93 Å) and one longer (2.36 Å) Cu–O bond lengths. Pb2+ is bonded to five O2- atoms to form PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four equivalent PbO5 square pyramids, and edges with four equivalent PbO5 square pyramids. There are one shorter (2.19 Å) and four longer (2.71 Å) Pb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Ho3+, and two equivalent Cu+1.67+ atoms. In the second O2- site, O2- is bonded to one Sr2+, one Cu+1.67+, and four equivalent Pb2+ atoms to form a mixture of distorted edge and corner-sharing OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to four equivalent Sr2+, one Cu+1.67+, and one Pb2+ atom to form distorted OSr4CuPb octahedra that share corners with four equivalent OSr4CuPb octahedra and edges with eight OSrCuPb4 octahedra. The corner-sharing octahedral tilt angles are 20°.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Magnetic and Magnetocaloric Properties of the A 2 LnSbO 6 Lanthanide Oxides on the Frustrated fcc Lattice

Frustrated lanthanide oxides are promising candidates for cryogen-free magnetic refrigeration due to their suppressed ordering temperatures and high magnetic moments. While much attention has been paid to the garnet and pyrochlore lattices, the magnetocaloric effect in frustrated face-centered cubic (fcc) lattices remains relatively unexplored. We previously showed that the frustrated fcc double perovskite Ba 2 GdSbO 6 is a top-performing magnetocaloric material (per mol Gd) because of its small nearest-neighbor interaction between spins. Here we investigate different tuning parameters to maximize the magnetocaloric effect in the family of fcc lanthanide oxides, A 2 LnSbO 6 (A = {Ba 2+ , Sr 2+ } and Ln = {Nd 3+ , Tb 3+ , Gd 3+ , Ho 3+ , Dy 3+ , Er 3+ }), including chemical pressure via the A site cation and the magnetic ground state via the lanthanide ion. Bulk magnetic measurements indicate a possible trend between magnetic short-range fluctuations and the field-temperature phase space of the magnetocaloric effect, determined by whether an ion is a Kramers or a non-Kramers ion. We report for the first time on the synthesis and magnetic characterization of the Ca 2 LnSbO 6 series with tunable site disorder that can be used to control the deviations from Curie–Weiss behavior. Taken together, these results suggest fcc lanthanide oxides as tunable systems for magnetocaloric design.

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

Materials Data on Sr2HoCu3(PbO4)2 by Materials Project

Pb2Sr2HoCu3O8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.66–2.84 Å. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.66–2.83 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.39–2.42 Å. In the second Ho3+ site, Ho3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.39–2.41 Å. There are four inequivalent Cu+1.67+ sites. In the first Cu+1.67+ site, Cu+1.67+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.87 Å. In the second Cu+1.67+ site, Cu+1.67+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four equivalent CuO5 square pyramids. There are four shorter (1.93 Å) and one longer (2.35 Å) Cu–O bond lengths. In the third Cu+1.67+ site, Cu+1.67+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four equivalent CuO5 square pyramids. There are four shorter (1.93 Å) and one longer (2.35 Å) Cu–O bond lengths. In the fourth Cu+1.67+ site, Cu+1.67+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.87 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to five O2- atoms to form distorted PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four equivalent PbO5 square pyramids, and edges with four equivalent PbO5 square pyramids. There are a spread of Pb–O bond distances ranging from 2.19–3.10 Å. In the second Pb2+ site, Pb2+ is bonded to five O2- atoms to form distorted PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four equivalent PbO5 square pyramids, and edges with four equivalent PbO5 square pyramids. There are a spread of Pb–O bond distances ranging from 2.19–3.10 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Ho3+, and two Cu+1.67+ atoms. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Ho3+, and two Cu+1.67+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Ho3+, and two Cu+1.67+ atoms. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Ho3+, and two Cu+1.67+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, one Cu+1.67+, and four Pb2+ atoms. In the sixth O2- site, O2- is bonded to four Sr2+, one Cu+1.67+, and one Pb2+ atom to form a mixture of distorted edge and corner-sharing OSr4CuPb octahedra. The corner-sharing octahedral tilt angles are 20°. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, one Cu+1.67+, and four Pb2+ atoms. In the eighth O2- site, O2- is bonded to four Sr2+, one Cu+1.67+, and one Pb2+ atom to form a mixture of distorted edge and corner-sharing OSr4CuPb octahedra. The corner-sharing octahedral tilt angles are 20°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2HoCu2(BiO4)2 by Materials Project

Sr2HoCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.59–2.78 Å. Ho3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Ho–O bond lengths are 2.39 Å. Cu+1.50+ is bonded to five O2- atoms to form distorted CuO5 square pyramids that share a cornercorner with one BiO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.89 Å) and one longer (2.57 Å) Cu–O bond lengths. Bi3+ is bonded to six O2- atoms to form distorted BiO6 octahedra that share corners with four equivalent BiO6 octahedra, a cornercorner with one CuO5 square pyramid, and edges with eight equivalent BiO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Bi–O bond distances ranging from 2.13–2.94 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Ho3+, and two equivalent Cu+1.50+ atoms. In the second O2- site, O2- is bonded to one Sr2+ and five equivalent Bi3+ atoms to form a mixture of edge and corner-sharing OSrBi5 octahedra. The corner-sharing octahedral tilt angles are 7°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+, one Cu+1.50+, and one Bi3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrHo2Al2O7 by Materials Project

Ho2SrAl2O7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, and faces with eight equivalent AlO6 octahedra. There are four shorter (2.63 Å) and eight longer (2.80 Å) Sr–O bond lengths. Ho3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ho–O bond distances ranging from 2.19–2.67 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five equivalent AlO6 octahedra and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Al–O bond distances ranging from 1.87–2.11 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+, two equivalent Ho3+, and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OSr4Al2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third O2- site, O2- is bonded in a 2-coordinate geometry to five equivalent Ho3+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Tuning the Radius Ratio to Enhance Thermoelectric Properties in the Zintl Compounds AM 2 Sb 2 (A = Ba, Sr; M = Zn, Cd)

Five novel Zintl phase solid solutions in the Ba 1–x Sr x Zn 2–y Cd y Sb 2 (0 ≤ x ≤ 0.13(1); 0 ≤ y ≤ 0.32(2)) system were successfully synthesized by the molten Pb metal-flux method, and the powder X-ray diffraction and single-crystal X-ray diffraction analyses proved that all five title compounds adopted the BaCu 2 S 2 -type phase having the orthorhombic Pnma space group (Z = 4, Pearson code oP20) with five crystallographically independent atomic sites. The previously studied BaCu 2 S 2 -type antimonides demonstrated a limited tolerance for doping in contrast to the CaAl 2 Si 2 -type antimonides. To understand the relatively narrower phase width and limited dopability of the title BaCu 2 S 2 -type phase than the CaAl 2 Si 2 -type phase in the overall Ba 1–x Sr x Zn 2–y Cd y Sb 2 system, the radius ratio of cations and anionic elements r + /r – for two structure types were thoroughly investigated. For the first time, the r + /r – ratio was identified as a critical factor for the phase selectivity: (1) r + /r – > 1 favored the BaCu 2 S 2 -type phase, and (2) r + /r – < 1 favored the CaAl 2 Si 2 -type phase. Further, we also revealed the structural transformation mechanism from the more widely observed CaAl 2 Si 2 -type phase to the title BaCu 2 S 2 -type phase as the relatively larger cationic elements were introduced to the system. A series of DFT calculations using the three hypothetical models indicated that a resonance peak near EF in the density of states curves was descended from the relatively flat band structure at several special symmetry points rationalizing the enhanced Seebeck coefficients of Ba 0.94(1) Sr 0.06 Zn 1.86(3) Cd 0.14 Sb 2 and Ba 0.96(1) Sr 0.04 Zn 1.68(2) Cd 0.32 Sb 2 . Electron localization function analysis rationalized the correlation between the polarity change of anionic Zn/Cd–Sb bonds and the charge carrier mobility on the anionic frameworks. Temperature-dependent thermoelectric properties were studied for the four title compounds, and the results proved that the Sr and Cd doping in the title Ba 1–x Sr x Zn 2–y Cd y Sb 2 system successfully enhanced the ZT values through the increased Seebeck coefficients and the reduced total thermal conductivities.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2Zn(HO)6 by Materials Project

Sr2Zn(HO3)2(H2)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of four hydrogen molecules and one Sr2Zn(HO3)2 sheet oriented in the (-1, 0, 2) direction. In the Sr2Zn(HO3)2 sheet, Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.43–2.60 Å. Zn2+ is bonded in a distorted square co-planar geometry to six O2- atoms. There are a spread of Zn–O bond distances ranging from 1.96–2.57 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+, one Zn2+, and one O2- atom. The O–O bond length is 1.54 Å. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+, one Zn2+, and one H1+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Sr2+, one Zn2+, and one O2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SrHo31Al2Si14N13O59 by Materials Project

SrHo31Al2Si14N13O59 crystallizes in the triclinic P1 space group. The structure is three-dimensional. Sr is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Sr–O bond distances ranging from 2.32–2.71 Å. There are thirty-one inequivalent Ho sites. In the first Ho site, Ho is bonded in a 6-coordinate geometry to one N and five O atoms. The Ho–N bond length is 2.27 Å. There are a spread of Ho–O bond distances ranging from 2.12–2.65 Å. In the second Ho site, Ho is bonded in a 7-coordinate geometry to one N and six O atoms. The Ho–N bond length is 2.63 Å. There are a spread of Ho–O bond distances ranging from 2.18–2.46 Å. In the third Ho site, Ho is bonded in a 8-coordinate geometry to one N and seven O atoms. The Ho–N bond length is 2.63 Å. There are a spread of Ho–O bond distances ranging from 2.21–3.07 Å. In the fourth Ho site, Ho is bonded in a 6-coordinate geometry to one N and five O atoms. The Ho–N bond length is 2.81 Å. There are a spread of Ho–O bond distances ranging from 2.21–2.46 Å. In the fifth Ho site, Ho is bonded in a 7-coordinate geometry to one N and five O atoms. The Ho–N bond length is 2.25 Å. There are a spread of Ho–O bond distances ranging from 2.18–2.61 Å. In the sixth Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.14–2.47 Å. In the seventh Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.16–2.60 Å. In the eighth Ho site, Ho is bonded in a 7-coordinate geometry to one N and six O atoms. The Ho–N bond length is 2.65 Å. There are a spread of Ho–O bond distances ranging from 2.19–2.54 Å. In the ninth Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.22–2.65 Å. In the tenth Ho site, Ho is bonded in a 4-coordinate geometry to four O atoms. There are a spread of Ho–O bond distances ranging from 2.13–2.28 Å. In the eleventh Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.23–2.60 Å. In the twelfth Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.19–2.51 Å. In the thirteenth Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.18–2.44 Å. In the fourteenth Ho site, Ho is bonded in a 8-coordinate geometry to one N and seven O atoms. The Ho–N bond length is 2.64 Å. There are a spread of Ho–O bond distances ranging from 2.21–2.82 Å. In the fifteenth Ho site, Ho is bonded in a 5-coordinate geometry to one N and four O atoms. The Ho–N bond length is 2.43 Å. There are a spread of Ho–O bond distances ranging from 2.19–2.31 Å. In the sixteenth Ho site, Ho is bonded in a 6-coordinate geometry to two N and four O atoms. There are one shorter (2.17 Å) and one longer (2.39 Å) Ho–N bond lengths. There are a spread of Ho–O bond distances ranging from 2.19–2.71 Å. In the seventeenth Ho site, Ho is bonded in a distorted see-saw-like geometry to four O atoms. There are a spread of Ho–O bond distances ranging from 2.09–2.35 Å. In the eighteenth Ho site, Ho is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Ho–O bond distances ranging from 2.21–2.64 Å. In the nineteenth Ho site, Ho is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ho–O bond distances ranging from 2.12–2.92 Å. In the twentieth Ho site, Ho is bonded in a 7-coordinate geometry to one N and six O atoms. The Ho–N bond length is 2.27 Å. There are a spread of Ho–O bond distances ranging from 2.17–3.08 Å. In the twenty-first Ho site, Ho is bonded in a 4-coordinate geometry to two N and three O atoms. There are one shorter (2.33 Å) and one longer (2.87 Å) Ho–N bond lengths. There are a spread of Ho–O bond distances ranging from 2.05–2.40 Å. In the twenty-second Ho site, Ho is bonded in a 6-coordinate geometry to three N and three O atoms. There are one shorter (2.40 Å) and two longer (2.41 Å) Ho–N bond lengths. There are two shorter (2.21 Å) and one longer (2.61 Å) Ho–O bond lengths. In the twenty-third Ho site, Ho is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ho–O bond distances ranging from 2.21–2.75 Å. In the twenty-fourth Ho site, Ho is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Ho–O bond distances ranging from 2.15–2.79 Å. In the twenty-fifth Ho site, Ho is bonded in a 6-coordinate geometry to one N and five O atoms. The Ho–N bond length is 2.39 Å. There are a spread of Ho–O bond distances ranging from 2.18–2.48 Å. In the twenty-sixth Ho site, Ho is bonded in a 6-coordinate geometry to one N and five O atoms. The Ho–N bond length is 2.33 Å. There are a spread of Ho–O bond distances ranging from 2.18–2.54 Å. In the twenty-seventh Ho site, Ho is bonded in a 7-coordinate geometry to two N and five O atoms. There are one shorter (2.34 Å) and one longer (2.73 Å) Ho–N bond lengths. There are a spread of Ho–O bond distances ranging from 2.18–2.75 Å. In the twenty-eighth Ho site, Ho is bonded to one N and six O atoms to form distorted HoNO6 pentagonal bipyramids that share a cornercorner with one SiNO3 tetrahedra, a cornercorner with one OHo3N tetrahedra, and an edgeedge with one SiNO3 tetrahedra. The Ho–N bond length is 2.40 Å. There are a spread of Ho–O bond distances ranging from 2.20–2.60 Å. In the twenty-ninth Ho site, Ho is bonded in a 7-coordinate geometry to two N and five O atoms. There are one shorter (2.52 Å) and one longer (2.60 Å) Ho–N bond lengths. There are a spread of Ho–O bond distances ranging from 2.29–2.44 Å. In the thirtieth Ho site, Ho is bonded in a 7-coordinate geometry to four N and four O atoms. There are a spread of Ho–N bond distances ranging from 2.20–3.13 Å. There are a spread of Ho–O bond distances ranging from 2.21–2.76 Å. In the thirty-first Ho site, Ho is bonded in a 3-coordinate geometry to one N and three O atoms. The Ho–N bond length is 2.53 Å. There are one shorter (2.08 Å) and two longer (2.13 Å) Ho–O bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to one N and three O atoms to form AlNO3 tetrahedra that share corners with two SiNO3 tetrahedra. The Al–N bond length is 1.84 Å. There are a spread of Al–O bond distances ranging from 1.77–1.85 Å. In the second Al site, Al is bonded in a tetrahedral geometry to one N and three O atoms. The Al–N bond length is 1.89 Å. There is two shorter (1.77 Å) and one longer (1.81 Å) Al–O bond length. There are fourteen inequivalent Si sites. In the first Si site, Si is bonded in a distorted trigonal non-coplanar geometry to one N and two O atoms. The Si–N bond length is 1.71 Å. There is one shorter (1.68 Å) and one longer (1.73 Å) Si–O bond length. In the second Si site, Si is bonded to one N and three O atoms to form SiNO3 tetrahedra that share an edgeedge with one HoNO6 pentagonal bipyramid. The Si–N bond length is 1.73 Å. There is two shorter (1.66 Å) and one longer (1.68 Å) Si–O bond length. In the third Si site, Si is bonded to two N and two O atoms to form corner-sharing SiN2O2 tetrahedra. There is one shorter (1.73 Å) and one longer (1.75 Å) Si–N bond length. There is one shorter (1.64 Å) and one longer (1.69 Å) Si–O bond length. In the fourth Si site, Si is bonded to one N and three O atoms to form edge-sharing SiNO3 tetrahedra. The Si–N bond length is 1.72 Å. There are a spread of Si–O bond distances ranging from 1.64–1.72 Å. In the fifth Si site, Si is bonded in a distorted trigonal non-coplanar geometry to one N and two O atoms. The Si–N bond length is 1.80 Å. There is one shorter (1.69 Å) and one longer (1.73 Å) Si–O bond length. In the sixth Si site, Si is bonded to two N and two O atoms to form corner-sharing SiN2O2 tetrahedra. There is one shorter (1.70 Å) and one longer (1.74 Å) Si–N bond length. There is one shorter (1.65 Å) and one longer (1.68 Å) Si–O bond length. In the seventh Si site, Si is bonded to one N and three O atoms to form corner-sharing SiNO3 tetrahedra. The Si–N bond length is 1.74 Å. There are a spread of Si–O bond distances ranging from 1.62–1.72 Å. In the eighth Si site, Si is bonded in a trigonal non-coplanar geometry to three O atoms. All Si–O bond lengths are 1.66 Å. In the ninth Si site, Si is bonded in a distorted trigonal planar geometry to two N and one O atom. There is one shorter (1.63 Å) and one longer (1.66 Å) Si–N bond length. The Si–O bond length is 1.63 Å. In the tenth Si site, Si is bonded to one N and three O atoms to form corner-sharing SiNO3 tetrahedra. The Si–N bond length is 1.71 Å. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the eleventh Si site, Si is bonded to two N and two O atoms to form SiN2O2 tetrahedra that share a cornercorner with one AlNO3 tetrahedra and an edgeedge with one SiNO3 tetrahedra. There is one shorter (1.65 Å) and one longer (1.74 Å) Si–N bond length. There is one shorter (1.73 Å) and one longer (1.74 Å) Si–O bond length. In the twelfth Si site, Si is bonded to one N and three O atoms to form SiNO3 tetrahedra that share a cornercorner with one AlNO3 tetrahedra and a cornercorner with one SiNO3 tetrahedra. The Si–N bond length is 1.71 Å. There are a spread of Si–O bond distances ranging from 1.66–1.70 Å. In the thirteenth Si site, Si is bonded to one N and three O atoms to form SiNO3 tetrahedra that share a cornercorner with one HoNO6 pentagonal bipyramid and a cornercorner with one SiN2O2 tetrahedra. The Si–N bond length is 1.72 Å. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the fourteenth Si site, Si is bonded in a trigonal non-coplanar geometry to two N and one O atom. Both Si–N bond lengths are 1.81 Å. The Si–O bond length is 1.70 Å. There are thirteen inequivalent N sites. In the first N site, N is bonded in a 2-coordinate geometry to one Ho and two Si atoms. In the second N site, N is bonded in a distorted T-shaped geometry to one Ho and two Si atoms. In the third N site, N is bonded in a distorted water-like geometry to two Ho, one Al, and one Si atom. In the fourth N site, N is bonded in a 4-coordinate geometry to two Ho and two Si atoms. In the fifth N site, N is bonded in a 4-coordinate geometry to three Ho and one Si atom. In the sixth N site, N is bonded in a 4-coordinate geometry to two Ho, one Si, and one O atom. The N–O bond length is 1.49 Å. In the seventh N site, N is bonded to three Ho and one Si atom to form distorted NHo3Si tetrahedra that share a cornercorner with one NHo3Si tetrahedra, a cornercorner with one OHo3Si trigonal pyramid, and an edgeedge with one OSrHo2Si trigonal pyramid. In the eighth N site, N is bonded to three Ho and one Si atom to form distorted NHo3Si tetrahedra that share a cornercorner with one NHo3Si tetrahedra, a cornercorner with one OHo4 tetrahedra, and a cornercorner with one OHo3Si trigonal pyramid. In the ninth N site, N is bonded in a 4-coordinate geometry to two Ho and two Si atoms. In the tenth N site, N is bonded in a 4-coordinate geometry to two Ho, one Si, and one O atom. The N–O bond length is 1.49 Å. In the eleventh N site, N is bonded in a 5-coordinate geometry to three Ho, one Al, and one Si atom. In the twelfth N site, N is bonded in a 2-coordinate geometry to three Ho, one Si, and one O atom. The N–O bond length is 1.53 Å. In the thirteenth N site, N is bonded in a distorted water-like geometry to one Ho and two Si atoms. There are fifty-nine inequivalent O sites. In the first O site, O is bonded in a 4-coordinate geometry to one Sr, two Ho, and one Si atom. In the second O site, O is bonded to one Sr, two Ho, and one Si atom to form distorted OSrHo2Si trigonal pyramids that share an edgeedge with one NHo3Si tetrahedra and an edgeedge with one OHo3Si trigonal pyramid. In the third O site, O is bonded to three Ho and one Si atom to form distorted O

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2HoCu2RuO8 by Materials Project

RuSr2HoCu2O8 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with eight equivalent SrO12 cuboctahedra, faces with five equivalent SrO12 cuboctahedra, faces with four equivalent RuO6 octahedra, and faces with four equivalent CuO5 square pyramids. There are a spread of Sr–O bond distances ranging from 2.67–3.03 Å. Ho3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are two shorter (2.39 Å) and six longer (2.40 Å) Ho–O bond lengths. Ru5+ is bonded to six O2- atoms to form RuO6 octahedra that share corners with four equivalent RuO6 octahedra, corners with two equivalent CuO5 square pyramids, and faces with eight equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.92 Å) and two longer (2.05 Å) Ru–O bond length. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one RuO6 octahedra, corners with four equivalent CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Cu–O bond distances ranging from 1.93–2.21 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Ho3+, and two equivalent Cu2+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+, two equivalent Ho3+, and two equivalent Cu2+ atoms. In the third O2- site, O2- is bonded to four equivalent Sr2+, one Ru5+, and one Cu2+ atom to form a mixture of distorted edge and corner-sharing OSr4CuRu octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the fourth O2- site, O2- is bonded in a linear geometry to four equivalent Sr2+ and two equivalent Ru5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Prediction of ambient pressure superconductivity in cubic ternary hydrides with MH 6 octahedra

Exploring high-temperature superconducting (high-T c ) material at ambient pressure holds immense significance for physics, chemistry, and materials science. In this study, we perform a high-throughput screening of strong electron-phonon interactions in X 2 MH 6 compounds (X = Li, Na, Mg, Al, K, Ca, Ga, Rb, Sr, and In; M are 3d, 4d, and 5d transition metals). These compounds have a cubic structure featuring an MH 6 octahedron motif. Our screening calculations suggest that 26 compounds exhibit dynamic stability and strong electron-phonon coupling. Among them, Mg 2 RhH 6 , Mg 2 IrH 6 , Al 2 MnH 6 , and Li 2 CuH 6 show promising energetic stability and T c of more than 50 K at ambient pressure. This study underscores promising high-T c compounds at ambient pressure with distinctive MH 6 motifs.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Evolution of Superconducting-Transition Temperature with Superfluid Density and Conductivity in Pressurized Cuprate Superconductors

What factors fundamentally determine the value of superconducting transition temperature T c in high temperature superconductors has been the subject of intense debate. Following the establishment of an empirical law known as Homes' law, there is a growing consensus in the community that the T c value of the cuprate superconductors is closely linked to the superfluid density (ρ s ) of its ground state and the conductivity (σ) of its normal state. However, all the data supporting this empirical law (ρ s = AσT c ) have been obtained from the ambient-pressure superconductors. In this study, we present the first high-pressure results about the connection of the quantities of ρ s and σ with T c , through the studies on the Bi 1.74 Pb 0.38 Sr 1.88 CuO 6+δ and Bi 2 Sr 2 CaCu 2 O 8+δ , in which the value of their high-pressure resistivity (ρ = 1/σ) is achieved by adopting our newly established method, while the quantity of ρs is extracted using Homes' law. In conclusion, we highlight that the T c values are strongly linked to the joint response factors of magnetic field and electric field, i.e., ρ s and σ, respectively, implying that the physics determining T c is governed by the intrinsic electromagnetic fields of the system.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Deep Learning Provides Substantial Improvements to County‐Level Fire Weather Forecasting Over the Western United States

Abstract The recent wildfires in the western United States during 2018 and 2020 caused record‐breaking fire damage and casualties. Despite remarkable advances in fire modeling and weather forecasting, it remains challenging to anticipate catastrophic wildfire events and associated damage. One key missing component is a fire weather prediction system with sufficiently long lead time capable of providing useful regional details. Here, we develop a hybrid prediction model of wildfire danger called CFS with super resolution (CFS‐SR) as a proof of concept to fill that void. The CFS‐SR model is constructed by integrating the Climate Forecast System version 2 with a deep learning (DL) technique from Single Image Super Resolution, a method widely used in enhancing image resolution. We show that for the 2018–2019 fire season, the CFS‐SR model significantly improves accuracy in forecasting fire weather at lead times of up to 7 days with an enhanced spatial resolution up to 4 km. This level of high resolution provides county‐level fire weather forecast, making it more practical for allocating resources to mitigate wildfire danger. Our study demonstrates that a proper combination of ensemble climate predictions with DL techniques can boost predictability at finer spatial scales, increasing the utility of fire weather forecasts for practical applications.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Twisted van der Waals Josephson Junction Based on a High-T c Superconductor

Stacking two-dimensional van der Waals (vdW) materials rotated with respect to each other show versatility for studying exotic quantum phenomena. In particular, anisotropic layered materials have great potential for such twistronics applications, providing high tunability. In this work, we report anisotropic superconducting order parameters in twisted Bi 2 Sr 2 CaCu 2 O 8+x (Bi-2212) vdW junctions with an atomically clean vdW interface, achieved using the microcleave-and-stack technique. The vdW junctions with twist angles of 0° and 90° showed the maximum Josephson coupling, comparable to that of intrinsic Josephson junctions. As the twist angle approaches 45°, Josephson coupling is suppressed, and eventually disappears at 45°. The observed twist angle dependence of the Josephson coupling can be explained quantitatively by theoretical calculation with the d-wave superconducting order parameter of Bi-2212 and finite tunneling incoherence of the junction. Our results revealed the anisotropic nature of Bi-2212 and provided a novel fabrication technique for vdW-based twistronics platforms compatible with air-sensitive vdW materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Lattice Effect on the Superexchange Interaction in Antiferromagnetic Bi 2.1 Sr 1.9 CaCu 2 O 8+δ

By employing Raman scattering and X-ray diffraction techniques on antiferromagnetic Bi 2.1 Sr 1.9 CaCu 2 O 8+δ within the same pressure conditions, we tracked the evolution of the two-magnon spectrum and structural parameters under pressures of up to nearly 30 GPa. Consequently, we established the relationship between pressure, in-plane lattice parameter d, and superexchange interaction J as J ~ d -(6.6±0.2 ). Within the examined pressure range, this compound did not exhibit superconductivity, as determined by a sensitive magnetic measurement technique. Additionally, we observed phonon anomalies, suggesting possible disorder effects in Bi-O layers and reduced charge transfer from these layers, particularly above 10 GPa. Finally, we discuss the impacts of pressure and chemical doping on J and the structure, along with their implications for superconductivity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Developing Accelerated Test Protocols and Tuning Microstructures of the Common Materials to Improve Robustness, Reliability, and Endurance of SOFC Cells

This work is built on our prior work where we found that phase transformation in praseodymium nickelates, e.g. Pr 2 NiO 4 (PNO) and (Pr 1-x Nd x ) 2 NiO 4 (PNNO), can be electrochemically driven, and is substantially faster when compared to thermal annealing studies. The first task aims at an attempt to further accelerate the phase transformation in the oxygen electrode by alternating the current input in the cells, which lead to the development of accelerated test protocols (ATPs). ATPs showed up to 60x faster phase transformation and up to 10x faster performance degradation in (Pr 0.50 Nd 0.50 ) 2 NiO 4 electrodes, when compared to long-term operation under constant current density. Furthermore, the phase stable Nd 2 NiO 4 and (La 0.6 Sr 0.4 )(Co 0.8 Fe 0.2 )O 3 (LSCF6482) electrodes were tested in full cells under ATPs, and showed up to 10x faster performance degradation within 1,100 hours in a comparison with long-term thermal annealing studies and electrochemical operation under constant current density. The second task aims at the quantification of the contributions of cell components to the total impedance of a solid oxide fuel cell (SOFC) using electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT). Specifically, the role of gas composition at both anode and cathode was systematically studied, aiming at deconvoluting, identifying and quantifying the contributions of different electrode processes. This was achieved by first tuning the partial pressure of H 2 at the anode and subsequently varying the partial pressure of O 2 at the cathode. The results suggest that, while DRT offers a viable way of deconvoluting different times distributions, additional attention is needed before assigning a peak to a specific electrode process due to the significant overlap of the contributions from the cathode and the anode. Density function theory studies show that both Pr-vacancies and O-defects play a key role on the activity and stability for nickelates towards oxygen reduction reaction. The resident O-interstitials and oxygen ions in the PrO layer form peroxide (O 2 2- ) nearby Pr vacancies. The O 2 2- limits oxygen-ion transport due to the required additional energy to break its O-O bond. We further calculated the formation and segregation energies for different Ln ions (La, Pr, Nd, Pm, Sm, Gd, Tb, Dy, and Ho) in PNO and CeO 2 (111) surfaces. In addition to Nd, Pm and La are suggested as potential dopants in PNO to enhance it stability without decomposition due to their more negative formation energies, lower diffusion energies, and positive separation energies.

01 COAL, LIGNITE, AND PEAT↗