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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mn(VSi3)2 by Materials Project

Mn(VSi3)2 is Titanium Disilicide-derived structured and crystallizes in the orthorhombic C222 space group. The structure is three-dimensional. V3+ is bonded in a distorted q6 geometry to ten Si+1.33- atoms. There are a spread of V–Si bond distances ranging from 2.47–2.60 Å. Mn2+ is bonded in a distorted q6 geometry to ten Si+1.33- atoms. There are a spread of Mn–Si bond distances ranging from 2.48–2.62 Å. There are two inequivalent Si+1.33- sites. In the first Si+1.33- site, Si+1.33- is bonded in a 10-coordinate geometry to two equivalent V3+, three equivalent Mn2+, and five Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.47–2.60 Å. In the second Si+1.33- site, Si+1.33- is bonded in a 10-coordinate geometry to four equivalent V3+, one Mn2+, and five Si+1.33- atoms. There are a spread of Si–Si bond distances ranging from 2.48–2.63 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(Mo3Se4)2 by Materials Project

Mn(Mo3Se4)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Mo+2.33+ sites. In the first Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.56–2.67 Å. In the second Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.56–2.67 Å. In the third Mo+2.33+ site, Mo+2.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.56–2.66 Å. Mn2+ is bonded in a distorted body-centered cubic geometry to eight Se2- atoms. There are a spread of Mn–Se bond distances ranging from 2.38–3.16 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Mn2+ atom. In the second Se2- site, Se2- is bonded in a 1-coordinate geometry to three Mo+2.33+ and one Mn2+ atom. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Mn2+ atom. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Mo+2.33+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(NbSe2)3 by Materials Project

Mn(NbSe2)3 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. there are two inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with three equivalent MnSe6 octahedra, edges with six NbSe6 pentagonal pyramids, and a faceface with one MnSe6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.61 Å) and three longer (2.63 Å) Nb–Se bond lengths. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six equivalent Se2- atoms to form distorted NbSe6 pentagonal pyramids that share corners with six equivalent MnSe6 octahedra and edges with six equivalent NbSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. All Nb–Se bond lengths are 2.63 Å. Mn2+ is bonded to six equivalent Se2- atoms to form MnSe6 octahedra that share corners with twelve NbSe6 pentagonal pyramids and faces with two equivalent NbSe6 pentagonal pyramids. All Mn–Se bond lengths are 2.43 Å. Se2- is bonded in a distorted rectangular see-saw-like geometry to three Nb+3.33+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(NbS2)2 by Materials Project

Mn(NbS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Nb3+ sites. In the first Nb3+ site, Nb3+ is bonded to six S2- atoms to form NbS6 octahedra that share corners with three equivalent NbS7 pentagonal bipyramids, edges with four equivalent NbS6 octahedra, and edges with two equivalent NbS7 pentagonal bipyramids. There are a spread of Nb–S bond distances ranging from 2.51–2.61 Å. In the second Nb3+ site, Nb3+ is bonded to seven S2- atoms to form distorted NbS7 pentagonal bipyramids that share corners with three equivalent NbS6 octahedra, edges with two equivalent NbS6 octahedra, and edges with four equivalent NbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 9–42°. There are a spread of Nb–S bond distances ranging from 2.55–2.72 Å. Mn2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Mn–S bond distances ranging from 2.49–2.81 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to four Nb3+ and two equivalent Mn2+ atoms to form distorted edge-sharing SMn2Nb4 octahedra. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three Nb3+ and two equivalent Mn2+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to three equivalent Nb3+ and two equivalent Mn2+ atoms. In the fourth S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Nb3+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(BMo)2 by Materials Project

Mn(MoB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.32 Å) and four longer (2.33 Å) Mo–B bond lengths. Mn2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Mn–B bond lengths are 2.33 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Mo2+, two equivalent Mn2+, and one B3- atom. The B–B bond length is 1.87 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn(BiSe2)2 by Materials Project

MnBi2Se4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Mn2+ sites. In the first Mn2+ site, Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with four equivalent BiSe6 octahedra, edges with two equivalent MnSe6 octahedra, and edges with six equivalent BiSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are two shorter (2.69 Å) and four longer (2.76 Å) Mn–Se bond lengths. In the second Mn2+ site, Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with two equivalent BiSe6 octahedra and edges with two equivalent MnSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are two shorter (2.59 Å) and four longer (2.81 Å) Mn–Se bond lengths. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with three MnSe6 octahedra, edges with three equivalent MnSe6 octahedra, and edges with four equivalent BiSe6 octahedra. The corner-sharing octahedra tilt angles range from 7–49°. There are a spread of Bi–Se bond distances ranging from 2.85–3.11 Å. In the second Bi3+ site, Bi3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Bi–Se bond distances ranging from 2.78–3.59 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Mn2+ and three equivalent Bi3+ atoms to form a mixture of distorted corner and edge-sharing SeMn2Bi3 square pyramids. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Mn2+ and three Bi3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent Mn2+ and three equivalent Bi3+ atoms to form a mixture of corner and edge-sharing SeMn2Bi3 square pyramids. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Mn2+ and four Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Performance of Al-Mn Transition-Edge Sensor Bolometers in SPT-3G

SPT-3G is a polarization-sensitive receiver, installed on the South Pole Telescope, that measures the anisotropy of the cosmic microwave background (CMB) from degree to arcminute scales. The receiver consists of ten 150-mm-diameter detector wafers, containing a total of similar to 16,000transition-edge sensor (TES) bolometers observing at 95, 150, and 220 GHz. During the 2018-2019 austral summer, one of these detector wafers was replaced by a new wafer fabricated with Al-Mn TESs instead of the Ti/Au design originally deployed for SPT-3G. We present the results of in-laboratory characterization and on-sky performance of this Al-Mn wafer, including electrical and thermal properties, optical efficiency measurements, and noise-equivalent temperature. In addition, we discuss and account for several calibration-related systematic errors that affect measurements made using frequency-domain multiplexing readout electronics.

Al-Mn↗
DOE OSTI2022

Effects of chemical segregation on ductility-anisotropy in high strength Fe-Mn-Al-C lightweight austenitic steels

Ductile Fe-Mn-Al-C lightweight steels offer great potential as high specific strength materials for weight critical applications. In the present work, very high yield (~1 GPa) and ultimate tensile strength levels (~1.5 GPa) were obtained along the rolling and transverse directions of Fe-30Mn-8.5Al-0.9Si-0.9C-0.5Mo (wt.%), with high tensile elongation to failure of ~35%. This excellent mechanical behavior was attributed to the nanoscale, ordered κ-carbide precipitates formed during aging after rolling. However, tensile ductility was not isotropic through all directions of the rolled plate. In particular, the ductility was consistently lower than 5% true strain along the normal direction. Upon detailed microstructural investigations, micro-scale lamellar chemical micro-segregation bands were detected, which caused the observed anisotropic embrittlement along certain plate directions. These bands resulted in low failure strains along the normal direction since it is oriented perpendicular to these chemical segregation bands, resulting in a failure type reminiscent of delamination-induced cleavage fracture. Chemical segregation causes an inhomogeneous κ-carbide precipitate distribution upon aging, producing more pronounced mechanical anisotropy after peak-aging as compared to the solution heat treated samples. Surprisingly, deformation twinning was observed after tensile deformation of solution-heat treated specimens via electron-backscatter diffraction experiments, which is anomalous for a high stacking faulty energy (SFE) material. Further, it was proposed that chemical micro-segregation promotes locally different SFE regions, leading to deformation twinning in this nominally high SFE material. Overall, this work demonstrates the effects of chemical segregation on mechanical properties and microstructural evolution in a high performance, lightweight Fe-Mn-Al-C steel.

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

Additively manufactured Al-Ce-Ni-Mn alloy with improved elevated-temperature fatigue resistance

Here, the high cycle fatigue behavior of an additively manufactured (AM) Al-10.5Ce-3.1Ni-1.2Mn wt% alloy was evaluated at 350 °C. The measured fatigue strength of 50 MPa at this temperature is comparable to the most fatigue resistant wrought Al alloys (2618-T6 and 7079-T6) at 315 °C. Refinement of pore populations through advanced AM processing in the examined alloy led to oxide inclusions becoming dominant fatigue crack initiation sites. The distribution of microstructural features that determine crack initiation was measured by X-ray computed tomography and served as input to make fatigue strength model predictions with various methodologies. A Monte-Carlo based approach that was previously applied to predict the fatigue strength of cast aluminum alloys through pore size distributions yielded accurate predictions for the fatigue strength of this AM alloy. Given the tunability of defect distributions in AM alloys, the sensitivity of the Al-Ce-Ni-Mn alloy fatigue behavior to defect distributions and outstanding elevated-temperature fatigue resistance of this alloy; the results together suggest the possibility of a new generation of fatigue-resistant alloys produced by the additive manufacturing route.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Influence of electronic transport on electrochemical performance of (Cu,Mn) 3 O 4 solid oxide fuel cell cathodes

Alkaline Earth free spinel oxides provide a potential benefit over Sr-doped perovskite-based materials commonly used as electrodes in high-temperature electrochemical energy conversion devices, e.g., solid oxide fuel cells (SOFCs). Sr-segregation is a known issue leading to performance degradation. In this study, Cu x Mn 3-x O 4 (x = 1, 1.2, and 1.5) porous electrodes were examined as SOFC cathodes using electrochemical impedance spectroscopy to investigate the oxygen reduction reaction (ORR) kinetics in relation to the material's intrinsic conductivity, the extrinsic electrode structure, and the cell test design. Similar to the electronic conducting (La,Sr)MnO 3 SOFC cathodes, the ORR kinetics of Cu x Mn 3-x O 4 spinel electrodes was governed by the oxygen adsorption and diffusion at the particle surface as well as the charge transfer at the triple phase boundaries. The overall electrode polarization resistance was highly dependent on contact density with the metallic current collector, active material particle connectivity, electrode thickness, and the intrinsic electronic materials conductivity. Here, we describe the importance of effective electronic charge transport parallel to the electrode surface in maximizing the electrochemically active electrode volume and enhancing electrode performance. We discuss an approach to optimize cell and electrode design with respect to active materials properties. This aspect is critical to ensure reliable evaluation of new materials, since laboratory-scale button-cells typically exhibit a high degree of electrode microstructure (e.g. porosity, thickness) and electrical contact density variation from sample to sample.

(Cu,Mn)3O4↗
DOE OSTI2025

Influence of stacking fault energy and hydrogen on deformation mechanisms in high Mn austenitic steels during in-situ tensile testing

High Mn austenitic steels are considered an economical alloy system for hydrogen storage and transport applications. This study used stacking fault energy (SFE) as a design parameter to achieve hydrogen embrittlement (HE)-resistant high Mn austenitic alloys. The role of hydrogen on the deformation mechanisms of low (29 mJ/m 2 ) and high SFE (49 mJ/m 2 ) alloys was evaluated through in-situ neutron diffraction during tensile loading. Hydrogen-precharging increased yield strength, partly due to hydrogen-induced lattice distortion (i.e., solute strengthening). Hydrogen accelerated the increase in defect density, including dislocations and stacking faults. The formation of planar deformation structures (twins and stacking faults), relative to dislocations, plays a critical role in promoting hydrogen-assisted fracture. The stacking fault frequency parameter obtained from neutron diffraction quantifies planar deformation tendencies, correlated with HE sensitivity. The higher SFE alloy exhibited greater resistance to HE, associated with the reduced propensity to form stacking faults and twins upon deformation in the hydrogen-precharged condition.

High Mn austenitic steel↗
DOE OSTI2023

In-situ investigation of strengthening and strain hardening mechanisms of Cu-added medium-Mn steels by synchrotron-based high-energy X-ray diffraction

A novel Cu-added medium-Mn steel with a chemical composition of Fe–0.27C–9.1Mn–1.86Al–3.3Cu (wt.%) was designed and subjected to intercritical annealing (IA) temperature range from 620 °C to 680 °C for 1 h. The ultimate tensile strength (UTS) increases and the yielding strength (YS) decreases with the IA temperature increasing. The YS of 824 MPa, UTS of 1222 MPa, total elongation (TE) of 55%, and product of strength and elongation (PSE) of 67.2 GPa·% are achieved after IA at 660 °C. Transmission electron microscopy confirmed that Cu-rich nanoparticles precipitate in the ferrite. The in-situ high-energy X-ray diffraction (HE-XRD) experiments show that at the beginning of plastic deformation, both austenite and ferrite bear the applied load. The load is mainly undertaken by martensite with effective transformation-induced plasticity (TRIP) effect triggered. The YS of ferrite is significantly higher than that of austenite. The individual contribution of solid solution strengthening, grain refinement strengthening, dislocation strengthening, and precipitation strengthening in ferrite and austenite is analyzed. The discrepancy between the YS of ferrite and austenite is mainly attributed to the precipitation strengthening due to the Cu-rich nanoparticles precipitation. The moderate mechanical stability and the collaboration of TRIP and twinning-induced plasticity (TWIP) effects of austenite contributed to the enhanced strain hardening capability and resulted in large ductility.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Na 4 Fe 1.5 Mn 1.5 (PO 4 ) 2 (P 2 O 7 ): A low-cost and earth-abundant cathode for robust sodium storage

The mixed compounds of phosphates and pyrophosphates are attractive cathodes for sodium-ion batteries (SIBs) owing to their robust open framework structure and superior diffusion dynamics. However, most reported mixed phosphate cathodes generally suffer from low operating potential. Herein, we develop a bimetallic Na 4 Fe 1.5 Mn 1.5 (PO 4 ) 2 (P 2 O 7 )/C-rGO (NFMPP/C-rGO) cathode, which possesses two working plateaus at 2.92 and 3.95 V. The obtained NFMPP/C-rGO demonstrates a stable high capacity of over 120 mAh g −1 at 0.1 C. In-situ XRD characterization discloses a solid solution reaction for the Fe 2+/3+ redox couple and a two-phase reaction for the Mn 2+/3+ redox couple. In conclusion, first-principles calculations reveal the migration of Na + in NFMPP has low barriers. This work provides a new, low-cost, earth-abundant, and stable cathode choice for practical SIBs.

Cathode materials↗
DOE OSTI2021

Thermal runaway mechanism of lithium-ion battery with LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode materials

Battery safety is critical to the application of lithium-ion batteries, especially for high energy density battery applied in electric vehicles. In this paper, the thermal runaway mechanism of LiNi 0.8 Co 0.1 Mn 0.1 O 2 based lithium-ion battery is illustrated. And the reaction between cathode and flammable electrolyte is proved as the trigger of the thermal runaway accident. In detail, with differential scanning calorimeter tests for battery components, the material combination contributing to thermal runaway was decoupled. Characterization with synchrotron X-ray diffraction and transmission electron microscopy with in-situ heating proved that the vigorous exothermic reaction is initiated by the liberated oxygen species. The pulse of highly active oxygen species reacted quickly with the electrolyte, accompanied with tremendous heat release, which accelerated the phase transformation of charged cathode. Also, the mechanism is verified by a confirmatory experiment when the highly active oxygen species were trapped by anion receptor, the phase transformation of the charged cathode was inhibited. Clarifying the thermal runaway mechanism of LiNi 0.8 Co 0.1 Mn 0.1 based lithium-ion battery may light the way to battery chemistries of both high energy density and high safety.

25 ENERGY STORAGE↗
DOE OSTI2020

Eutectic Synthesis of the P2-Type Na x Fe 1/2 Mn 1/2 O 2 Cathode with Improved Cell Design for Sodium-Ion Batteries

An engaging area of research in sodium-ion batteries (SIBs) has been focusing on discovery, design, and synthesis of high-capacity cathode materials in order to boost energy density to levels close enough to that of state-of-the-art lithium-ion batteries. Of particular interest, P2-type layered oxide, Na 2/3 Fe 1/2 Mn 1/2 O 2 , has been researched as a potential cathode in SIBs based on its high theoretical capacity of 260 mA h/g and use of noncritical materials. However, the reported synthesis methods are not only complex and energy-demanding but also often yield inhomogeneous and impure materials with capacities less than 200 mA h/g under impractical test conditions. Here, we report a novel synthesis route using low-temperature eutectic reaction to produce highly homogeneous, crystalline, and impurity-free P2-Na x Fe 1/2 Mn 1/2 O 2 with enhanced Na-ion diffusivity and kinetics. The overall electrochemical performances of the Na-ion cells have been improved by pairing the P2-cathode with presodiated hard carbon anodes, leading to reversible capacities in the range of 180 mA h/g. This new approach is a contribution toward the simplification of synthesis and scalability of sodium-based cathodes with high crystallinity and fine-tuned morphology and the realization of a sodium-ion battery system with lower cost and improved electrochemical performance.

25 ENERGY STORAGE↗
DOE OSTI2023

Probing rutile solid-phase crystallization of atomically mixed Mn-alloyed TiO 2 coatings through XANES analysis

Phase transformation via dopant introduction is an emerging strategy for tuning the electronic and catalytic properties of oxides. However, developing a general theory of ternary alloys and their microstructure evolution remains challenging due to the knowledge gaps in how point defects such as dopants lead to the formation of complex or metastable phases. We investigate the influence of Mn concentration and annealing temperature on the microstructure evolution of amorphous Mn-alloyed TiO 2 synthesized via Atomic Layer Deposition. In conclusion, our findings reveal a new crystallization pathway resulting in a direct amorphous TiO 2 to rutile transformation without an intermediate anatase phase and our multi-parameter thermal processing conditions show potential for AI-assisted data acquisition and analysis for studying complex oxide coatings.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Fermi Surface Nesting and Anomalous Hall Effect in Magnetically Frustrated Mn 2 PdIn

Noncollinear magnets with near-zero net magnetization and nontrivial bulk electronic topology hold significant promise for spintronic applications, though their scarcity necessitates deliberate design strategies. In this work, a topologically nontrivial electronic structure is reported in metallic Mn 2 PdIn, which crystallizes in the inverse Heusler structure and exhibits a spin-glassy ground state with quenched magnetization. The system features Weyl-type band crossings near the Fermi level and reveals a novel interplay among momentum-space nesting, orbital hybridization, and spin-orbit coupling. Comprehensive magnetotransport measurements reveal a pronounced anomalous Hall effect (AHE) in Mn 2 PdIn. The observed quadratic relationship between the longitudinal and anomalous Hall resistivities highlights the dominance of the intrinsic Berry curvature contribution to the AHE. These findings establish inverse Heusler alloys as compelling platforms for realizing noncollinear magnets that host Weyl-type semimetallic or metallic phases-combining suppressed magnetization with robust electronic transport-thereby offering a promising route toward their seamless integration into next-generation spintronic devices.

Ahmed, Afsar [Saha Institute of Nuclear Physics, K↗
DOE OSTI2022

Quantum Sensing and Imaging of Spin–Orbit-Torque-Driven Spin Dynamics in the Non-Collinear Antiferromagnet Mn 3 Sn

Novel non-collinear antiferromagnets with spontaneous time-reversal symmetry breaking, non-trivial band topology, and unconventional transport properties have received immense research interest over the past decade due to their rich physics and enormous promise in technological applications. One of the central focuses in this emerging field is exploring the relationship between the microscopic magnetic structure and exotic material properties. Nanoscale imaging of both spin–orbit-torque-induced deterministic magnetic switching and chiral spin rotation in non-collinear antiferromagnet Mn 3 Sn films using nitrogen-vacancy (NV) centers are reported. Direct evidence of the off-resonance dipole–dipole coupling between the spin dynamics in Mn 3 Sn and proximate NV centers is also demonstrated by NV relaxometry measurements. These results demonstrate the unique capabilities of NV centers in accessing the local information of the magnetic order and dynamics in these emergent quantum materials and suggest new opportunities for investigating the interplay between topology and magnetism in a broad range of topological magnets.

36 MATERIALS SCIENCE↗