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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Zr2Ti3(PbO3)5 by Materials Project

Zr2Ti3(PbO3)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Zr–O bond distances ranging from 1.97–2.52 Å. In the second Zr4+ site, Zr4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Zr–O bond distances ranging from 1.97–2.52 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.75–2.08 Å. In the second Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.75–2.09 Å. In the third Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.75–2.09 Å. There are five inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.52–2.98 Å. In the second Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.51–2.94 Å. In the third Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.47–2.91 Å. In the fourth Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.46–2.92 Å. In the fifth Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pb–O bond distances ranging from 2.48–2.98 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Zr4+ and four Pb2+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to one Ti4+ and four Pb2+ atoms. In the third O2- site, O2- is bonded in a single-bond geometry to one Ti4+ and four Pb2+ atoms. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Ti4+ and four Pb2+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Zr4+ and four Pb2+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Zr4+ and two Pb2+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ti4+ and two Pb2+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ti4+ and two Pb2+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ti4+ and two Pb2+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Zr4+ and two Pb2+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Zr4+ and two equivalent Pb2+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Zr4+, one Ti4+, and two equivalent Pb2+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ti4+ and two equivalent Pb2+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Ti4+ and two equivalent Pb2+ atoms. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Zr4+, one Ti4+, and two equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaNd4(CoO3)5 by Materials Project

BaNd4(CoO3)5 is Orthorhombic Perovskite-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form distorted BaO12 cuboctahedra that share corners with two equivalent BaO12 cuboctahedra and faces with eight CoO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.60–3.06 Å. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.35–2.78 Å. In the second Nd3+ site, Nd3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.36–2.77 Å. There are three inequivalent Co+3.20+ sites. In the first Co+3.20+ site, Co+3.20+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra and a faceface with one BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 15–26°. There are a spread of Co–O bond distances ranging from 1.89–2.05 Å. In the second Co+3.20+ site, Co+3.20+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 10–26°. There are a spread of Co–O bond distances ranging from 1.93–2.02 Å. In the third Co+3.20+ site, Co+3.20+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 18–26°. There are a spread of Co–O bond distances ranging from 1.94–2.04 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Ba2+, two equivalent Nd3+, and two Co+3.20+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two equivalent Nd3+, and two Co+3.20+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ba2+, two Nd3+, and two Co+3.20+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+, two Nd3+, and two Co+3.20+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Nd3+ and two equivalent Co+3.20+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to one Ba2+, two Nd3+, and two Co+3.20+ atoms. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three Nd3+ and two Co+3.20+ atoms. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Nd3+, and two equivalent Co+3.20+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Dy12(ReC3)5 by Materials Project

Dy12(ReC3)5 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded to five C+3.47- atoms to form distorted DyC5 square pyramids that share corners with three equivalent DyC5 square pyramids, edges with four equivalent DyC8 hexagonal bipyramids, and an edgeedge with one DyC5 square pyramid. There are a spread of Dy–C bond distances ranging from 2.34–2.57 Å. In the second Dy3+ site, Dy3+ is bonded to eight C+3.47- atoms to form distorted DyC8 hexagonal bipyramids that share corners with four equivalent DyC8 hexagonal bipyramids, edges with two equivalent DyC8 hexagonal bipyramids, and edges with eight equivalent DyC5 square pyramids. There are a spread of Dy–C bond distances ranging from 2.58–2.79 Å. In the third Dy3+ site, Dy3+ is bonded in a rectangular see-saw-like geometry to four C+3.47- atoms. There are two shorter (2.52 Å) and two longer (2.55 Å) Dy–C bond lengths. There are two inequivalent Re+3.20+ sites. In the first Re+3.20+ site, Re+3.20+ is bonded in a distorted T-shaped geometry to three C+3.47- atoms. There are one shorter (1.95 Å) and two longer (2.06 Å) Re–C bond lengths. In the second Re+3.20+ site, Re+3.20+ is bonded in a trigonal planar geometry to three equivalent C+3.47- atoms. All Re–C bond lengths are 1.91 Å. There are four inequivalent C+3.47- sites. In the first C+3.47- site, C+3.47- is bonded to five Dy3+ and one Re+3.20+ atom to form a mixture of distorted edge and corner-sharing CDy5Re octahedra. The corner-sharing octahedra tilt angles range from 5–44°. In the second C+3.47- site, C+3.47- is bonded in a 6-coordinate geometry to four Dy3+, one Re+3.20+, and one C+3.47- atom. The C–C bond length is 1.36 Å. In the third C+3.47- site, C+3.47- is bonded in a 5-coordinate geometry to four Dy3+ and one C+3.47- atom. In the fourth C+3.47- site, C+3.47- is bonded to four Dy3+ and two equivalent Re+3.20+ atoms to form CDy4Re2 octahedra that share corners with four equivalent CDy4Re2 octahedra and edges with four equivalent CDy5Re octahedra. The corner-sharing octahedra tilt angles range from 5–26°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tb12(ReC3)5 by Materials Project

Tb12(ReC3)5 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to five C+3.47- atoms to form distorted TbC5 square pyramids that share a cornercorner with one CTb4ReC octahedra, corners with three equivalent TbC5 square pyramids, edges with four equivalent TbC8 hexagonal bipyramids, and an edgeedge with one TbC5 square pyramid. The corner-sharing octahedral tilt angles are 42°. There are a spread of Tb–C bond distances ranging from 2.36–2.59 Å. In the second Tb3+ site, Tb3+ is bonded to eight C+3.47- atoms to form distorted TbC8 hexagonal bipyramids that share corners with four equivalent TbC8 hexagonal bipyramids, corners with two equivalent CTb4ReC octahedra, edges with two equivalent TbC8 hexagonal bipyramids, and edges with eight equivalent TbC5 square pyramids. The corner-sharing octahedral tilt angles are 98°. There are a spread of Tb–C bond distances ranging from 2.59–2.80 Å. In the third Tb3+ site, Tb3+ is bonded in a rectangular see-saw-like geometry to four C+3.47- atoms. There are two shorter (2.54 Å) and two longer (2.57 Å) Tb–C bond lengths. There are two inequivalent Re+3.20+ sites. In the first Re+3.20+ site, Re+3.20+ is bonded in a distorted T-shaped geometry to three C+3.47- atoms. There are one shorter (1.95 Å) and two longer (2.06 Å) Re–C bond lengths. In the second Re+3.20+ site, Re+3.20+ is bonded in a trigonal planar geometry to three equivalent C+3.47- atoms. All Re–C bond lengths are 1.91 Å. There are four inequivalent C+3.47- sites. In the first C+3.47- site, C+3.47- is bonded to five Tb3+ and one Re+3.20+ atom to form a mixture of corner and edge-sharing CTb5Re octahedra. The corner-sharing octahedra tilt angles range from 5–74°. In the second C+3.47- site, C+3.47- is bonded to four Tb3+, one Re+3.20+, and one C+3.47- atom to form distorted CTb4ReC octahedra that share corners with two equivalent TbC8 hexagonal bipyramids, corners with six CTb5Re octahedra, corners with two equivalent TbC5 square pyramids, and edges with six CTb5Re octahedra. The corner-sharing octahedra tilt angles range from 42–74°. The C–C bond length is 1.35 Å. In the third C+3.47- site, C+3.47- is bonded in a 5-coordinate geometry to four Tb3+ and one C+3.47- atom. In the fourth C+3.47- site, C+3.47- is bonded to four Tb3+ and two equivalent Re+3.20+ atoms to form CTb4Re2 octahedra that share corners with four equivalent CTb4Re2 octahedra and edges with six CTb5Re octahedra. The corner-sharing octahedra tilt angles range from 5–27°.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Rare-Earth Permanent Magnet SmCo 5 for Chiral Interfacial Spin-Orbitronics

Interfacially asymmetric magnetic multilayers made of heavy metal/ferromagnet have attracted considerable attention in the spintronics community for accommodating spin-orbit torques (SOTs) and meanwhile for hosting chiral spin textures. In these multilayers, the accompanied interfacial Dzyaloshinskii–Moriya interaction (iDMI) permits the formation of Néel-type spin textures. While significant progresses have been made in Co, CoFeB, Co 2 FeAl, CoFeGd based multilayers, it would be intriguing to identify new magnetic multilayers that could enable spin-torque controllability and meanwhile host nanoscale skyrmions. In this report, first, thin films made of permanent magnet SmCo 5 with perpendicular magnetic anisotropy are synthesized, in which the deterministic SOT switching, enabled by the spin Hall effect, in Pt/SmCo 5 /Ta trilayer is demonstrated. Further, the stabilization of room-temperature skyrmions with diameters ≈100 nm in [Pt/SmCo 5 /Ta] 15 , together with a skyrmionium-like spin texture in [Pt/SmCo 5 /Ir] 15 multilayers is shown. Based on the material specific parameters, micromagnetic simulations are also carried out. The results confirm the presence of chiral spin textures in this new material family. Through interfacial engineering, the results thus demonstrate that rare earth permanent magnets could be a new platform for studying interfacial chiral spintronics.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Tuning the Kinetics of Zinc-Ion Insertion/Extraction in V 2 O 5 by In Situ Polyaniline Intercalation Enables Improved Aqueous Zinc-Ion Storage Performance

Rechargeable zinc-ion batteries (ZIBs) are emerging as a promising alternative for Li-ion batteries. However, the developed cathodes suffer from sluggish Zn 2+ diffusion kinetics, leading to poor rate capability and inadequate cycle life. Herein, an in situ polyaniline (PANI) intercalation strategy is developed to facilitate the Zn 2+ (de)intercalation kinetics in V 2 O 5 . In this way, a remarkably enlarged interlayer distance (13.90 Å) can be constructed alternatively between the V-O layers, offering expediting channels for facile Zn 2+ diffusion. Importantly, the electrostatic interactions between the Zn 2+ and the host O 2- , which is another key factor in hindering the Zn 2+ diffusion kinetics, can be effectively blocked by the unique π-conjugated structure of PANI. As a result, the PANI-intercalated V 2 O 5 exhibits a stable and highly reversible electrochemical reaction during repetitive Zn 2+ insertion and extraction, as demonstrated by in situ synchrotron X-ray diffraction and Raman studies. Further first-principles calculations clearly reveal a remarkably lowered binding energy between Zn 2+ and host O 2- , which explains the favorable kinetics in PANI-intercalated V 2 O 5 . Benefitting from the above, the overall electrochemical performance of PANI-intercalated V 2 O 5 electrode is remarkable improved, exhibiting excellent high rate capability of 197.1 mAh g -1 at current density of 20 A g -1 with capacity retention of 97.6% over 2000 cycles.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Direct Catalytic Conversion of Ethanol to C 5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability

Abstract Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C 5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd‐promoted ZnO‐ZrO 2 catalyst. The sequence of reaction steps involved in the C 5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross‐aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C 5+ ketones and the stability of the catalyst. A yield of >70 % to C 5+ ketones was achieved over a 0.1 % Pd‐ZnO‐ZrO 2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.

Subramaniam, Senthil↗
DOE OSTI2026

Giant Magnetostriction in Ferrimagnetic SmFe 5 As 3

Magnetostrictive materials are of interest not only from a fundamental perspective but also for their potential applications, spanning spintronics to energy harvesting. A new magnetostrictive material—SmFe 5 As 3 —reveals a complex interplay between magnetostriction, magnetic properties, and the crystal structure behavior. The ground state of SmFe 5 As 3 is ferrimagnetic, as evidenced by magnetic susceptibility data, band-structure calculations, and XANES measurements. At T m1 = 28 ± 4 K, part of the Fe sublattice reorients, transitioning into a ferromagnetic state. This is followed by an entrance into the paramagnetic state at T m2 = 76 ± 4 K. The effects observed in the magnetic measurements are accompanied by structural phase transitions. All three phases—below T m1 , between T m1 and T m2 , and above T m2 —are described by the same structural motif of the UCr 5 P 3 type (monoclinic space group P2 1 /m), differing only in the degree of deformation of the Fe–As framework. The new material exhibits giant magnetostriction of 2500 x 10 -6 . Dilatometry measurements on a SmFe 5 As 3 single crystal indicate strongly diverse behavior, exhibiting not only negative, but also zero, as well as positive thermo-elastic effects.

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

Magnetocaloric Effect in Lightly‐Doped Fe 5 Si 3 Single Crystals

Abstract Development of promising new materials for above room temperature magnetic cooling applications relies on careful balancing of structure and composition to maximize accessible metastable phases that can drive a strong magnetocaloric effect (MCE). However, the working temperatures of these materials may fall outside of desired application windows. In this work, it is shown that it is possible to control metastable phase stability temperatures of Fe 5 Si 3 through selection of appropriate spin and charge doping. Here, the parent material's desired structure appears only within a narrow temperature range from 1098 to 1303 K. Doping with Mn and P is shown to allow stabilization of the parent's high temperature phase and resulting MCE to room temperature. The structural and magnetic properties, and the magnetocaloric effect of single crystal Fe 4.83 Mn 0.16 Si 2.91 P 0.09 (FMSP) are investigated experimentally and theoretically. A first‐order magneto‐elastic transition is observed at 348 K, where magnetic onset is accompanied by a change in lattice volume without an apparent change in crystal symmetry. Although the trace Mn and P doping are found to decrease the T C , the maximum magnetic entropy change Δ S Max ( T ) and the relative cooling power (RCP) of FMSP are enhanced compared to polycrystalline Fe 5 Si 3 . As a result, an intrinsically broader entropy change over a larger temperature span is generated in the lightly doped single crystal of Fe 5 Si 3 . The magnetic moment of the system is also enhanced. Density functional theory (DFT) calculations are performed to gain microscopic insights into the experimental findings. The results suggest that the hexagonal Fe 5 Si 3 is a new giant room temperature MCE material that is on par with La–Fe–Si and Fe‐Mn‐P‐Si systems.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Photodetachment Dynamics and Structural Flexibility of Undercoordinated Iridium Halides IrCl n − (n = 3−5): An Experimental and Theoretical Investigation

Three undercoordinated iridium chloride anions, IrCl n − (n = 3–5), and their neutral counterparts were investigated by cryogenic anion photoelectron spectroscopy and theoretical calculations. Photodetachment of IrCl n − leads to the formation of the corresponding neutral complex, i.e., a triplet ground state for n = 3, a quartet for n = 4, and close-lying singlet and triplet for n = 5. The vertical detachment energies are determined to be 3.89, 4.98, and 5.14 eV for n = 3, 4, and 5, respectively, revealing superhalogen anion properties with increasing electron detachment energies as chloride ligands added. The IrCl 3 − spectrum features an extremely broad, lowest electron binding energy band, attributed to resonant autodetachment with prominent non-Franck–Condon profiles. In IrCl 5 − , detachment prompts a d-orbital rearrangement that drives a structural transformation from a twisted square-based pyramidal to a trigonal–bipyramidal geometry in the singlet state. In conclusion, these findings provide insights into the electronic and structural adaptability of iridium halides, advancing our understanding of ligand exchange reactions and dissociative stability in transition metal complexes.

Tang, Peng [East China Normal Univ. (ECNU), Shangh↗
DOE OSTI2024

Screening a knowledge‐based library of low molecular weight compounds against the proline biosynthetic enzyme 1‐pyrroline‐5‐carboxylate 1 ( PYCR1)

Abstract Δ 1 ‐pyrroline‐5‐carboxylate reductase isoform 1 (PYCR1) is the last enzyme of proline biosynthesis and catalyzes the NAD(P)H‐dependent reduction of Δ 1 ‐pyrroline‐5‐carboxylate toL‐proline. High PYCR1 gene expression is observed in many cancers and linked to poor patient outcomes and tumor aggressiveness. The knockdown of thePYCR1gene or the inhibition of PYCR1 enzyme has been shown to inhibit tumorigenesis in cancer cells and animal models of cancer, motivating inhibitor discovery. We screened a library of 71 low molecular weight compounds (average MW of 131 Da) against PYCR1 using an enzyme activity assay. Hit compounds were validated with X‐ray crystallography and kinetic assays to determine affinity parameters. The library was counter‐screened against human Δ 1 ‐pyrroline‐5‐carboxylate reductase isoform 3 and proline dehydrogenase (PRODH) to assess specificity/promiscuity. Twelve PYCR1 and one PRODH inhibitor crystal structures were determined. Three compounds inhibit PYCR1 with competitive inhibition parameter of 100 μM or lower. Among these, (S)‐tetrahydro‐2H‐pyran‐2‐carboxylic acid (70 μM) has higher affinity than the current best tool compoundN‐formyl‐l‐proline, is 30 times more specific for PYCR1 over human Δ 1 ‐pyrroline‐5‐carboxylate reductase isoform 3, and negligibly inhibits PRODH. Structure‐affinity relationships suggest that hydrogen bonding of the heteroatom of this compound is important for binding to PYCR1. The structures of PYCR1 and PRODH complexed with 1‐hydroxyethane‐1‐sulfonate demonstrate that the sulfonate group is a suitable replacement for the carboxylate anchor. This result suggests that the exploration of carboxylic acid isosteres may be a promising strategy for discovering new classes of PYCR1 and PRODH inhibitors. The structure of PYCR1 complexed withl‐pipecolate and NADH supports the hypothesis that PYCR1 has an alternative function in lysine metabolism.

Biochemistry & Molecular Biology↗
DOE OSTI2020

Stacking Faults and Short-Range Magnetic Correlations in Single Crystal Y 5 Ru 2 O 12 : A Structure with Ru +4.5 One-Dimensional Chains

In this paper, the synthesis, structure, and physical properties of Y 5 Ru 2 O 12 , a new member of the Ln 5 B 2 O 12 class (Ln = lanthanide, B = Ru, Re, Mo) are reported. Single crystals of Y 5 Ru 2 O 12 are synthesized using a high-temperature, high-pressure (700 °C, 200 MPa) hydrothermal method. The structure features edge-sharing Ru—O—Ru 1D chains of distorted RuO6 octahedra. The YO n (n = 6 and 7) polyhedral groups bridge Ru—O—Ru chains across the unit cell by forming a complex 3D structure. The Ru—O—Ru chains contain alternating shorter and longer Ru—Ru distances along the chain. Single crystal neutron diffraction shows streak-like diffuse scattering along the H-direction, due to stacking faults. Temperature-dependent anisotropic magnetic measurements reveal a broad feature over a wide temperature range, with a maximum at ≈70 K indicating potential short-range ordering, with canted antiferromagnetic behavior below 30 K. The dominant magnetic interactions are antiferromagnetic with a large negative Weiss temperature θ ≈ –200 K. The compound has an effective magnetic moment that is anomalously large for this class of compounds (≈4 μ B Ru –1 ), and a phenomenological spin Hamiltonian describing the unusual anisotropic magnetization of Y 5 Ru 2 O 12 is proposed.

36 MATERIALS SCIENCE↗
DOE OSTI2022

A Low-Voltage Layered Na 2 TiGeO 5 Anode for Lithium-Ion Battery

Titanium-based anode materials have achieved much progress with the wide studies in lithium-ion batteries. However, these known materials usually possess high discharge voltage platforms and limited energy densities. In this work, a titanium-based oxide of Na 2 TiGeO 5 with layered structure, two-dimensional lamellar frame and exposed highly active (001) facet, exhibiting good electrochemical performance in terms of high capacity (410 mAh g –1 with a current density of 50 mA g –1 ), excellent rate capability and cycling stability with no obvious capacity attenuation after 4000 cycles, is reported. The appropriate discharge voltage plateau at around 0.2 V endows the Na 2 TiGeO 5 anode material high security compared with graphite and high energy density compared with spinel Li 4 Ti 5 O 12 . Combining the electrochemical tests and the density functional theory calculations, the Li + storage mechanism of Na 2 TiGeO 5 is elucidated and the conversion reaction process is revealed. More importantly, this study provides a way to develop low-voltage and high-capacity titanium-based anode materials for efficient energy storage.

25 ENERGY STORAGE↗
DOE OSTI2023

Vanadium and Niobium MXenes—Bilayered V 2 O 5 Asymmetric Supercapacitors

MXenes offer high metallic conductivity and redox capacitance that are attractive for high-power, high-energy storage devices. However, they operate limitedly under high anodic potentials due to irreversible oxidation. Pairing them with oxides to design asymmetric supercapacitors may expand the voltage window and increase the energy storage capabilities. Hydrated lithium preintercalated bilayered V 2 O 5 ( δ-Li x V 2 O 5 ·nH 2 O) is attractive for aqueous energy storage due to its high Li capacity at high potentials; however, its poor cyclability remains a challenge. To overcome its limitations and achieve a wide voltage window and excellent cyclability, it is combined with V 2 C and Nb 4 C 3 MXenes. Asymmetric supercapacitors employing lithium intercalated V 2 C (Li-V 2 C) or tetramethylammonium intercalated Nb 4 C 3 (TMA-Nb 4 C 3 ) MXenes as the negative electrode, and a δ-Li x V 2 O 5 ·nH 2 O composite with carbon nanotubes as the positive electrode in 5 m LiCl electrolyte operate over wide voltage windows of 2 and 1.6 V, respectively. The latter shows remarkably high cyclability—capacitance retention of ≈95% after 10 000 cycles. Here, this work highlights the importance of selecting appropriate MXenes to achieve a wide voltage window and a long cycle life in combination with oxide anodes to demonstrate the potential of MXenes beyond Ti 3 C 2 in energy storage.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Observable proton decay in flipped SU(5)

We explore proton decay in a class of realistic supersymmetric flipped SU(5) models supplemented by a U(1) R symmetry which plays an essential role in implementing hybrid inflation. Two distinct neutrino mass models, based on inverse seesaw and type I seesaw, are identified, with the latter arising from the breaking of U(1) R by nonrenormalizable superpotential terms. Depending on the neutrino mass model an appropriate set of intermediate scale color triplets from the Higgs superfields play a key role in proton decay channels that include p → (e + , μ + ) π 0 , p → (e + , μ + ) K 0 , p → $\bar v$π + , and p → $\bar v$K + . We identify regions of the parameter space that yield proton lifetime estimates which are testable at Hyper-Kamiokande and other next generation experiments. We discuss how gauge coupling unification in the presence of intermediate scale particles is realized, and a Z 4 symmetry is utilized to show how such intermediate scales can arise in flipped SU(5). Finally, we compare our predictions for proton decay with previous work based on SU(5) and flipped SU(5).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

J/ ψ elliptic and triangular flow in Pb-Pb collisions at \( \sqrt{s_{\mathrm{NN}}} \) = 5 . 02 TeV

The inclusive J/ ψ elliptic ( v 2 ) and triangular ( v 3 ) flow coefficients measured at forward rapidity (2 . 5 < y < 4) and the v 2 measured at midrapidity (| y | < 0 . 9) in Pb-Pb collisions at \( \sqrt{s_{\mathrm{NN}}} \) = 5 . 02 TeV using the ALICE detector at the LHC are reported. The entire Pb-Pb data sample collected during Run 2 is employed, amounting to an integrated luminosity of 750 μ b – 1 at forward rapidity and 93 μ b – 1 at midrapidity. The results are obtained using the scalar product method and are reported as a function of transverse momentum p T and collision centrality. At midrapidity, the J/ ψ v 2 is in agreement with the forward rapidity measurement. The centrality averaged results indicate a positive J/ ψ v 3 with a significance of more than 5 σ at forward rapidity in the p T range 2 < p T < 5 GeV/ c . The forward rapidity v 2 , v 3 , and v 3 /v 2 results at low and intermediate p T ( p T ≲ 8 GeV/ c ) exhibit a mass hierarchy when compared to pions and D mesons, while converging into a species-independent curve at higher p T . At low and intermediate p T , the results could be interpreted in terms of a later thermalization of charm quarks compared to light quarks, while at high p T , path-length dependent effects seem to dominate. The J/ ψ v 2 measurements are further compared to a microscopic transport model calculation. Using a simplified extension of the quark scaling approach involving both light and charm quark flow components, it is shown that the D-meson v n measurements can be described based on those for charged pions and J/ ψ flow.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Recursion relations for 5-point conformal blocks

We consider 5-point functions in conformal field theories in d2 dimensions. Using weight-shifting operators, we derive recursion relations which allow for the computation of arbitrary conformal blocks appearing in 5-point functions of scalar operators, reducing them to a linear combination of blocks with scalars exchanged. We additionally derive recursion relations for the conformal blocks which appear when one of the external operators in the 5-point function has spin 1 or 2. Our results allow us to formulate positivity constraints using 5-point functions which describe the expectation value of the energy operator in bilocal states created by two scalars.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2026

Chemo-Mechanics of α-V 2 O 5 During Lithiation and Implications for Rechargeable Battery Cathodes

Chemo-mechanical degradation of layered oxide electrodes is strongly influenced by crystallographic anisotropy, local stress evolution, and ion insertion, yet the intrinsic mechanical response of layered materials remains incompletely understood. Indeed, most prior studies have focused on polycrystalline materials but single crystals enable direct observation of coupling between anisotropic ion diffusion and mechanical response. This study aims to determine how crystallographic anisotropy and lithiation affect deformation, fracture, and mechanical properties in single-crystal V 2 O 5 , and compares this behavior with polycrystalline counterparts. Polycrystalline V 2 O 5 thin films and single-crystal α-V 2 O 5 were studied using nanoindentation, scanning electron microscopy, focused ion beam cross-sectioning, and Raman spectroscopy. Single crystals were tested in pristine and chemically lithiated states, including experiments in which crystals were first plastically deformed via nanoindentation and subsequently lithiated. Polycrystalline films exhibited significantly higher hardness and elastic modulus than single crystals. Single crystals indented normal to the exposed (001) basal plane exhibited pronounced anisotropic deformation, including directional slip, crystallographically-guided cracking, anisotropic crack propagation, interlayer separation, and shear localization. Lithiation caused substantial softening, reduced hardness and modulus, and suppressed displacement bursts during nanoindentation, while previously indented regions showed crack formation and growth upon lithiation. Mechanical behavior of α-V 2 O 5 is strongly governed by crystallographic anisotropy and further altered by lithiation, with pre-existing deformation serving as a strong driver of fracture during ion insertion. These findings illuminate the coupling among ion insertion, deformation, and fracture in layered oxides and provide a basis for understanding and mitigating mechanical failure in electrochemical energy-storage materials.

Anisotropy↗