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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba(TmS2)2 by Materials Project

BaTm2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.19–3.37 Å. There are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Tm–S bond distances ranging from 2.67–2.74 Å. In the second Tm3+ site, Tm3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Tm–S bond distances ranging from 2.69–2.76 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Tm3+ atoms. In the second S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing SBa2Tm3 square pyramids. In the third S2- site, S2- is bonded to two equivalent Ba2+ and three Tm3+ atoms to form a mixture of distorted edge and corner-sharing SBa2Tm3 trigonal bipyramids. In the fourth S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Tm3+ atoms to form a mixture of distorted edge and corner-sharing SBa2Tm3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(SbPd)2 by Materials Project

BaPd2Sb2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight Sb3- atoms. There are four shorter (3.64 Å) and four longer (3.68 Å) Ba–Sb bond lengths. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded to four equivalent Sb3- atoms to form a mixture of edge and corner-sharing PdSb4 tetrahedra. All Pd–Sb bond lengths are 2.76 Å. In the second Pd2+ site, Pd2+ is bonded in a 5-coordinate geometry to five Sb3- atoms. All Pd–Sb bond lengths are 2.75 Å. There are two inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a 4-coordinate geometry to four equivalent Ba2+ and four equivalent Pd2+ atoms. In the second Sb3- site, Sb3- is bonded in a 9-coordinate geometry to four equivalent Ba2+ and five Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(CO2)2 by Materials Project

BaC2O4 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.78–2.90 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.26 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(CO2)2 by Materials Project

BaC2O4 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ba2+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Ba–O bond distances ranging from 2.80–3.12 Å. There are two inequivalent C3+ sites. In the first C3+ site, C3+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.17 Å) and one longer (1.18 Å) C–O bond length. In the second C3+ site, C3+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.31 Å) and one longer (1.32 Å) C–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C3+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one C3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one C3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(SmS2)2 by Materials Project

BaSm2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Ba–S bond distances ranging from 3.24–3.46 Å. There are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to six S2- atoms to form a mixture of corner and edge-sharing SmS6 octahedra. The corner-sharing octahedra tilt angles range from 49–65°. There are a spread of Sm–S bond distances ranging from 2.77–2.86 Å. In the second Sm3+ site, Sm3+ is bonded to six S2- atoms to form a mixture of corner and edge-sharing SmS6 octahedra. The corner-sharing octahedra tilt angles range from 49–65°. There are a spread of Sm–S bond distances ranging from 2.77–2.85 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Sm3+ atoms. In the second S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Sm3+ atoms to form a mixture of corner and edge-sharing SBa2Sm3 square pyramids. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Sm3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Ba2+ and three equivalent Sm3+ atoms to form a mixture of distorted corner and edge-sharing SBa2Sm3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(NiAs)2 by Materials Project

BaNi2As2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ba2+ is bonded in a body-centered cubic geometry to eight equivalent As3- atoms. There are four shorter (3.42 Å) and four longer (3.50 Å) Ba–As bond lengths. Ni2+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing NiAs4 tetrahedra. There are a spread of Ni–As bond distances ranging from 2.35–2.38 Å. As3- is bonded in a 4-coordinate geometry to four equivalent Ba2+ and four equivalent Ni2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(SO2)4 by Materials Project

BaS3O8S crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four hydrogen sulfide molecules and one BaS3O8 framework. In the BaS3O8 framework, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–3.13 Å. There are three inequivalent S+3.50+ sites. In the first S+3.50+ site, S+3.50+ is bonded in a single-bond geometry to one O2- atom. The S–O bond length is 1.49 Å. In the second S+3.50+ site, S+3.50+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.46 Å) and one longer (1.47 Å) S–O bond length. In the third S+3.50+ site, S+3.50+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.45 Å) and two longer (1.46 Å) S–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Ba2+ and one S+3.50+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Ba2+ and one S+3.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(GaP)2 by Materials Project

BaGa2P2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ba2+ is bonded to six P3- atoms to form distorted edge-sharing BaP6 pentagonal pyramids. There are a spread of Ba–P bond distances ranging from 3.22–3.37 Å. There are two inequivalent Ga2+ sites. In the first Ga2+ site, Ga2+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are a spread of Ga–P bond distances ranging from 2.44–2.49 Å. In the second Ga2+ site, Ga2+ is bonded in a trigonal non-coplanar geometry to three P3- atoms. There are a spread of Ga–P bond distances ranging from 2.44–2.48 Å. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded to three equivalent Ba2+ and three Ga2+ atoms to form a mixture of distorted edge and corner-sharing PBa3Ga3 octahedra. The corner-sharing octahedra tilt angles range from 23–100°. In the second P3- site, P3- is bonded to three equivalent Ba2+ and three Ga2+ atoms to form a mixture of distorted edge and corner-sharing PBa3Ga3 octahedra. The corner-sharing octahedra tilt angles range from 22–100°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(FeSe2)2 by Materials Project

BaFe2Se4 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent Se2- atoms to form BaSe12 cuboctahedra that share corners with eight equivalent FeSe4 tetrahedra, edges with eight equivalent BaSe12 cuboctahedra, edges with eight equivalent FeSe4 tetrahedra, and faces with two equivalent BaSe12 cuboctahedra. There are four shorter (3.41 Å) and eight longer (3.69 Å) Ba–Se bond lengths. Fe3+ is bonded to four equivalent Se2- atoms to form FeSe4 tetrahedra that share corners with four equivalent BaSe12 cuboctahedra, edges with four equivalent BaSe12 cuboctahedra, and edges with two equivalent FeSe4 tetrahedra. All Fe–Se bond lengths are 2.27 Å. Se2- is bonded in a 5-coordinate geometry to three equivalent Ba2+ and two equivalent Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(CuSb)2 by Materials Project

BaCu2Sb2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight Sb3- atoms. There are four shorter (3.53 Å) and four longer (3.68 Å) Ba–Sb bond lengths. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to four equivalent Sb3- atoms to form a mixture of edge and corner-sharing CuSb4 tetrahedra. All Cu–Sb bond lengths are 2.71 Å. In the second Cu2+ site, Cu2+ is bonded in a 5-coordinate geometry to five Sb3- atoms. There are one shorter (2.65 Å) and four longer (2.74 Å) Cu–Sb bond lengths. There are two inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a 4-coordinate geometry to four equivalent Ba2+ and four equivalent Cu2+ atoms. In the second Sb3- site, Sb3- is bonded in a 9-coordinate geometry to four equivalent Ba2+ and five Cu2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(FeSb3)4 by Materials Project

BaFe4Sb12 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent Sb1- atoms to form BaSb12 cuboctahedra that share faces with eight equivalent FeSb6 octahedra. All Ba–Sb bond lengths are 3.47 Å. Fe+2.50+ is bonded to six equivalent Sb1- atoms to form FeSb6 octahedra that share corners with six equivalent FeSb6 octahedra and faces with two equivalent BaSb12 cuboctahedra. The corner-sharing octahedral tilt angles are 53°. All Fe–Sb bond lengths are 2.58 Å. Sb1- is bonded in a 2-coordinate geometry to one Ba2+, two equivalent Fe+2.50+, and two equivalent Sb1- atoms. There are one shorter (3.00 Å) and one longer (3.02 Å) Sb–Sb bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Revisiting the structures and phase transitions of Ba 2 NaNb 5 O 15

The room-temperature and low-temperature structure(s) of Ba 2 NaNb 5 O 15 (BNN) have been debated since the structure was proposed in the 1960s. This work revisits the structures and phase transitions of BNN, combining high-resolution X-ray and neutron powder diffraction with density functional theory calculations. Temperature-dependent high-resolution X-ray powder diffraction patterns are collected from 4 to 918 K, and sequential batch Rietveld refinement using a symmetry mode approach to describe the structure is used to extract the main structural changes as a function of temperature. The data show that the average structure of BNN is best described by the Ama2 space group, and no other structural phase transitions were observed below the ferroelastic transition. The symmetry mode analysis, combining results from diffraction and density functional theory, shows significant octahedral tilting and corrugations of both the A1 and A2 sites along the c direction. A strong correlation between the spontaneous strain and the octahedral tilting was observed, and a potential connection with emerging microstructure at low temperatures is proposed, all enabled by the symmetry mode approach used in this work.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1993

Cross Sections for Electron Scattering by Ground State Ba; Elastic Scattering and Excitation of the ...6s6p (sup 1)P(sub 1) Level

Differential cross sections for elastic and inelastic (6s6p (sup 1)P(sub 1)) electron scattering from ground state Ba atom have been measured at 5eV, 10eV, 15eV, and 20eV impact energies in the angular range from 0(sup 0) to 130(sup 0). Extrapolation to the larger angles have been performed using theoretical calculations as a guide, and integral and momentum transfer cross sections were derived. Theoretical calculations based on two channel clos coupling and relativistic and non-relativistic distorted wave methods have been compared with the present results. Good agreement between experiment and various theoretical results is found at small scattering angles but significant deviations exist at larger scattering angles.

electon scattering extrapolation scattering angles↗
DOE OSTI2024

Localized Flexoelectric Effect Around Ba(CuNb) Nano‐Clusters in Epitaxial BiFeO 3 Films for Enhancement of Electric and Multiferroic Properties

Abstract Room‐temperature (RT) multiferroic materials have received significant research attention for various potential applications; however, their properties are not suitable for real‐world implementation. In this study, a nano‐scale localized flexoelectric effect is introduced to enhance the RT multiferroic performance of epitaxial bismuth iron oxide (BiFeO 3 ; BFO) thin films by embedding 10 mol% Ba(Cu 1/3 Nb 2/3 )O 3 (BCN) nano‐clusters into the host BFO film, which originally has a rhombohedral crystal structure. By utilizing nano‐clustering, a large out‐of‐plane coherent strain is localized around the nano‐clusters, resulting in a highly strained tetragonality of the BFO structure; subsequently, the films exhibit peculiar types of domains and domain walls, such as nano‐scale rotational vortices and antiparallel dipole configurations. These peculiar domain structures, which originate from the localized flexoelectric effect at the nano‐scale, enable excellent ferroelectric, ferromagnetic, and RT multiferroic magnetoelectric coupling. This study reveals that the local variation in the localized flexoelectric field around nano‐clusters considerably impacts the formation of unusual domain‐wall structures. This suggests that the controlled introduction of nano‐clusters with different crystal structures is promising for achieving the desired multiferroic properties.

Song, Hyunseok↗
DOE OSTI2025

Structural Phase Separation and Enhanced Superconductivity in La 1.875 Ba 0.125 CuO 4 Under Uniaxial Strain

Strain engineering has attracted significant attention in recent years due to its capability in tuning lattice and electronic structures of quantum materials. Using moderate uniaxial compressive strain, structural phase separation is induced in the low-temperature phase of x = 1/8 La 2-x Ba x CuO 4 (LBCO) single crystals. These structures are low temperature tetragonal (LTT), low temperature less orthorhombic (LTLO), and a plastically deformed nano-domain structure (PDNS), comprised of few-nanometer-sized orthorhombic domains within an amorphous matrix. These three structures exhibit distinct superconducting behaviors. The volume fraction of the LTT structure is suppressed with increasing strain, while its superconducting transition temperature increases and broadens. The LTLO structure exhibits a sharp superconducting transition above 32 K, which increases up to ≈ 36 K at maximum strain. The PDNS phase exhibits a very broad superconducting transition and persists even after removing the strain. This study illustrates the sensitivity of superconductivity to the structure of the LBCO sample near its stripe instability.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Synthesis, Structural Characterization and Chemical Bonding of Sr 7 Li 6 Sn 12 and its Quaternary Derivatives with Eu and Alkaline Earth Metal (Mg, Ca, Ba) Substitutions. A Tale of Seven Li‐Containing Stannides and Two Complex Crystal Structures

In this paper, we discuss the synthesis and the structural characterization of the new ternary compound Sr 7 Li 6 Sn 12 and its six quaternary derivatives, where alkaline earth metals (Ca, Mg, Ba) and the rare earth metal Eu are substituted, yielding crystalline phases of monoclinic or orthorhombic symmetry. The title compounds were synthesized via high‐temperature solid‐state reactions of the corresponding elements. The crystal structures were determined by single‐crystal X‐ray diffraction methods. The (Sr,Ca) 7 Li 6 Sn 12 and Eu 7 (Mg,Li) 6 Sn 12 phases represent a new structure type (space group P 2/ m , No. 10) while Sr 7 Li 6 Sn 12 and the rest of the title phases crystallize in the orthorhombic base‐centered space group Cmmm (No. 65) which is similar to the Eu 7 Li 8– x Sn 10+ x ( x ≈ 2.0) phase with the Ce 7 Li 8 Ge 10 structure type (Pearson code oC 50). Careful examination of the resulting structures shows intricate disordering between Li and Sn atoms, which is governed by the total number of valence electrons. The discussion of experimental results is also supported by DFT electronic structure calculations.

Osman, Hussien H.↗
DOE OSTI2024

Ab initio exploration of low–lying electronic states of linear and bent MNX + (M = Ca, Sr, Ba, Ra; X = O, S, Se, Te, Po) and their origins

High-level multireference and coupled cluster quantum calculations were employed to analyze low-lying electronic states of linear-MNX + and side-bonded-M[NX] + (M = Ca, Sr, Ba, Ra; X = O, S, Se, Te, Po) species. Their full potential energy curves (PECs), dissociation energies (D e s), geometric parameters, excitation energies (T e s), and harmonic vibrational frequencies (ω e s) are reported. The first three chemically bound electronic states of MNX + and M[NX] + are 3 Σ – , 1 Δ, 1 Σ + and 3 A", 1 A', 1 A", respectively. The 3 Σ – , 1 Δ, 1 Σ + of MNX + originate from the M + ( 2 D) + NX( 2 Π) fragments, whereas the 3 A", 1 A', 1A" states of M[NX] + dissociate to M + ( 2 S) + NX( 2 Π) as a result of avoided crossings. The MNX + and M[NX] + are real minima on the potential energy surface and their interconversions are possible. The M 2+ NX – /M 2+ [NX] – ionic structure is an accurate representation for their low-lying electronic states. The D e s of MNX + species were found to depend on the dipole moment (μ) of the corresponding NX ligands and a linear relationship between these two parameters was observed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Simultaneous creation of a large vapor plume and pumice raft by the 2021 Fukutoku-Oka-no-Ba shallow submarine eruption

The 12 August 2021 eruption of Fukutoku-Oka-no-Ba, a shallow submarine volcano in the Izu-Bonin arc of Japan, is one of few documented submarine eruptions to make a large aerial plume and floating pumice raft. Relative to past eruptions, this event was well-covered by multiple high resolution satellite remote sensors, raising the possibility of resolving important questions about the timing of raft and plume formation, and their relationship. Here we use satellite remote sensing to assess the eruption timeline, style, rates, and products. We use the Himawari-8 satellite to assess the plume volume flux and height through time. In addition, we use a combination of ultra-high resolution satellite imagery to assess the timing and mechanisms of raft formation. We find that the 16 km eruption plume was ice-rich and conclude that the 0.1 km3 raft and eruption plume were co-genetic. Finally, we suggest that pumice clasts were delivered to the raft by tephra jets, ballistics, and near-vent fallout from the plume. Together our observations reveal that the fallout of pumice lapilli from a water-rich eruption column generated a large pumice raft.

58 GEOSCIENCES↗