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DOE OSTI2025

Cleavable quaternary oxychlorides with high magnetic ordering temperatures

Quaternary oxychlorides derived from Ruddlesden–Popper 3d transition metal oxides offer a route to cleavable crystals with bulk antiferromagnetic ordering temperatures reaching at least 550 K. Here, we study the magnetic, optical, and mechanical behavior of Sr 2 FeO 3 Cl, Ca 2 FeO 3 Cl, Ca 3 Fe 2 O 5 Cl 2 , and Sr 3 Fe 2 O 5 Cl 2 . Through optical absorption measurements, we show that these antiferromagnetic semiconductors have optical band gaps of ≈2.1(1) eV. The magnetic ordering symmetries and temperatures were probed by neutron powder diffraction and Mössbauer spectroscopy on polycrystalline samples, demonstrating Néel temperatures (T N ) near room temperature in the single layer Sr 2 FeO 3 Cl (T N ≈ 311 K) and Ca 2 FeO 3 Cl (T N ≈ 360 K), and the double-layer compound Sr 3 Fe 2 O 5 Cl 2 has T N ≈ 545 K. The high-spin moments of Fe 3+ lie within the basal plane and the magnetic structures are compensated within each magnetic layer and characterized by magnetic propagation vectors k = ($\frac{1}{2}$ $\frac{1}{2}$ 0). Magnetization results demonstrate the quasi-2D nature of the magnetism, with a broad maximum in the susceptibility near 2T N for Sr 2 FeO 3 Cl. Scotch tape tests and mechanical exfoliation onto SiO 2 confirm the micaceous nature of these crystals with cleavage down to a single unit cell (two magnetic layers) achieved for Sr 3 Fe 2 O 5 Cl 2 . In conclusion, this paper highlights strong antiferromagnetic interactions, semiconducting band gaps, and cleavability of quaternary Fe-based oxychlorides and motivates future work on crystals and exfoliated flakes of these and related oxyhalide systems.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Observation of a critical charge mode in a strange metal

Understanding the strange metallic behavior that develops at the brink of localization in quantum materials requires probing the underlying electronic charge dynamics. Using synchrotron radiation–based Mössbauer spectroscopy, we studied the charge fluctuations of the strange metal phase of β-YbAlB 4 as a function of temperature and pressure. We found that the usual single absorption peak in the Fermi-liquid regime splits into two peaks upon entering the critical regime. Here, we interpret this spectrum as a single nuclear transition, modulated by nearby electronic valence fluctuations whose long time scales are further enhanced by the formation of charged polarons. These critical charge fluctuations may prove to be a distinct signature of strange metals.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2024

Momentum-exchange interactions in a Bragg atom interferometer suppress Doppler dephasing

Large ensembles of laser-cooled atoms interacting through infinite-range photon-mediated interactions are powerful platforms for quantum simulation and sensing. Here we realize momentum-exchange interactions in which pairs of atoms exchange their momentum states by collective emission and absorption of photons from a common cavity mode, a process equivalent to a spin-exchange or XX collective Heisenberg interaction. The momentum-exchange interaction leads to an observed all-to-all Ising-like interaction in a matter-wave interferometer. A many-body energy gap also emerges, effectively binding interferometer matter-wave packets together to suppress Doppler dephasing in analogy to Mössbauer spectroscopy. The tunable momentum-exchange interaction expands the capabilities of quantum interaction–enhanced matter-wave interferometry and may enable the realization of exotic behaviors, including simulations of superconductors and dynamical gauge fields.

Science & Technology - Other Topics↗

DOE OSTI2024

Scale-Up of Lithium Iron & Aluminum Nickelate Advanced Cathode and Fabrication of A Battery Pack Comprising The Same

Global battery manufacturers are increasingly worried about the serious supply chain constraint caused by rapid fluctuations in cobalt prices over the years. We present a novel cobalt-free, nickel-rich layered cathode material called NFA class (LiNixFeyAlzO2) to tackle this challenge. Spherical NFA(OH)2 precursors were successfully synthesized by incorporating Ni, Fe, and Al elements using a co-precipitation reaction in a continuous stirred tank reactor. The LiNFAO2 cathode, composed of LiNi0.85Fe0.05Al0.1O2, was synthesized and analyzed using X-Ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy (SEM). The material's electrochemical behavior was evaluated through various techniques at different lithiation/delithiation states in two voltage ranges. The cobalt-free material exhibits a high capacity of 190 mAh/g at 0.1C within the voltage range of 3V-4.5V, as demonstrated by electrochemical performance evaluations. Rate and cycling evaluations showed good rate capability and cycling stability, with 88% capacity retention after 100 cycles at C/3 within the voltage range of 3V-4.3V. Our research shows the great potential of cobalt-free NFA cathodes as a feasible option for developing cost-effective lithium-ion batteries.

25 ENERGY STORAGE↗

DOE OSTI2024

Scale-Up of Lithium Iron & Aluminum Nickelate Advanced Cathode and Fabrication of A Battery Pack Comprising The Same

25 ENERGY STORAGE↗

DOE OSTI2020

Limiting Retained Austenite Decomposition in Quenched and Tempered Steels: Influences of Rapid Tempering and Silicon

Tempering reactions are critical to microstructure and property control in martensitic steels. Here, retained austenite decomposition and cementite precipitation are monitored using Mössbauer spectroscopy in 4340 and 300-M steel under conventional and rapid tempering conditions. Tempering times are compared at a constant tempered hardness by increasing tempering temperatures associated with short time conditions to achieve equivalent matrix softening to that of longer tempering times. Time-temperature combinations that provide equivalent tempered hardness generated microstructures with similar dislocation densities and cementite precipitation fractions; these mechanisms are controlled by self-diffusion. However, systematic differences in retained austenite content were observed at a given degree of softening, where shorter tempering times exhibited higher levels of retained austenite compared to more conventional conditions. At low temperatures, the differences in retained austenite preservation between explored time-temperature conditions are attributed to corresponding differences in carbon diffusion distance (in austenite), the controlling diffusional process of retained austenite decomposition. At higher temperatures, retained austenite decomposition exhibits C-curve kinetic behavior in 4340. Thus, reduced thermodynamic driving force for cementite and ferrite formation at higher temperature is believed to play a role in restricting retained austenite decomposition within some short-time, high temperature tempering regimes. The addition of silicon pushes cementite precipitation and retained austenite decomposition to higher temperatures, although retained austenite decomposition is suppressed to a greater extent than cementite precipitation. Potential is illustrated for coupling rapid tempering with silicon alloying to produce appreciably tempered martensite (~490 HV) with relatively less retained austenite decomposition compared to conventional tempering conditions.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Effects of Fe(III) Oxide Mineralogy and Phosphate on Fe(II) Secondary Mineral Formation during Microbial Iron Reduction

The bioreduction of Fe(III) oxides by dissimilatory iron-reducing bacteria may result in the formation of a suite of Fe(II)-bearing secondary minerals, including magnetite (a mixed Fe(II)/Fe(III) oxide), siderite (Fe(II) carbonate), vivianite (Fe(II) phosphate), chukanovite (ferrous hydroxy carbonate), and green rusts (mixed Fe(II)/Fe(III) hydroxides). In an effort to better understand the factors controlling the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of Fe(III) oxide mineralogy, phosphate concentration, and the availability of an electron shuttle (9,10-anthraquinone-2,6-disulfonate, AQDS) on the bioreduction of a series of Fe(III) oxides (akaganeite, feroxyhyte, ferric green rust, ferrihydrite, goethite, hematite, and lepidocrocite) by Shewanella putrefaciens CN32, and the resulting formation of secondary minerals, as determined by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. The overall extent of Fe(II) production was highly dependent on the type of Fe(III) oxide provided. With the exception of hematite, AQDS enhanced the rate of Fe(II) production; however, the presence of AQDS did not always lead to an increase in the overall extent of Fe(II) production and did not affect the types of Fe(II)-bearing secondary minerals that formed. The effects of the presence of phosphate on the rate and extent of Fe(II) production were variable among the Fe(III) oxides, but in general, the highest loadings of phosphate resulted in decreased rates of Fe(II) production, but ultimately higher levels of Fe(II) than in the absence of phosphate. In addition, phosphate concentration had a pronounced effect on the types of secondary minerals that formed; magnetite and chukanovite formed at phosphate concentrations of ≤1 mM (ferrihydrite), <~100 µM (lepidocrocite), 500 µM (feroxyhyte and ferric green rust), while green rust, or green rust and vivianite, formed at phosphate concentrations of 10 mM (ferrihydrite), ≥100 µM (lepidocrocite), and 5 mM (feroxyhyte and ferric green rust). These results further demonstrate that the bioreduction of Fe(III) oxides, and accompanying Fe(II)-bearing secondary mineral formation, is controlled by a complex interplay of mineralogical, geochemical, and microbiological factors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Solvent Influence on the Magnetization and Phase of Fe-Ni Alloy Nanoparticles Generated by Laser Ablation in Liquids

The synthesis of bimetallic iron-nickel nanoparticles with control over the synthesized phases, particle size, surface chemistry, and oxidation level remains a challenge that limits the application of these nanoparticles. Pulsed laser ablation in liquid allows the properties tuning of the generated nanoparticles by changing the ablation solvent. Organic solvents such as acetone can minimize nanoparticle oxidation. Yet, economical laboratory and technical grade solvents that allow cost-effective production of FeNi nanoparticles contain water impurities, which are a potential source of oxidation. Here, we investigated the influence of water impurities in acetone on the properties of FeNi nanoparticles generated by pulsed laser ablation in liquids. To remove water impurities and produce “dried acetone”, cost-effective and reusable molecular sieves (3 Å) are employed. The results show that the Fe50Ni50 nanoparticles’ properties are influenced by the water content of the solvent. The metastable HCP FeNi phase is found in NPs prepared in acetone, while only the FCC phase is observed in NPs formed in water. Mössbauer spectroscopy revealed that the FeNi nanoparticles oxidation in dried acetone is reduced by 8% compared to acetone. The high-field magnetization of Fe50Ni50 nanoparticles in water is the highest, 68 Am2/kg, followed by the nanoparticles obtained after ablation in acetone without water impurities, 59 Am2/kg, and acetone, 52 Am2/kg. The core-shell structures formed in these three liquids are also distinctive, demonstrating that a core-shell structure with an outer oxide layer is formed in water, while carbon external layers are obtained in acetone without water impurity. The results confirm that the size, structure, phase, and oxidation of FeNi nanoparticles produced by pulsed laser ablation in liquids can be modified by changing the solvent or just reducing the water impurities in the organic solvent.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Electrical and Magnetic Properties of FeGa 3 with Antisite Disorder

We investigated the electronic and magnetic ground states of the cage compound FeGa 3 under the presence of Fe antisite disorder (namely as Fe 0.258 Ga 0.742 ) by x-ray diﬀraction (XRD), Mössbauer spectroscopy (MS), magnetization and electrical resistivity. Our results show that approximately 4.5 (5)% Fe antisite occupying one of the two non-equivalent Ga sites changes signiﬁcantly the electronic and magnetic ground states of the pristine compound. We uncover that Fe 0.258 Ga 0.742 undergoes two magnetic transitions, T 1 ≈ 60 K and T 2 ≈ 15 K, the latter associated with the suppression of semiconducting behavior. We focus our discussion on the role that in-gap impurity states and spin disorder play across semiconducting-metal and paramagnetic-magnetic transitions.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Metallic d-wave altermagnetism in WFeB: a platform for electrically switchable perpendicular spin-splitter response

We report the synthesis and magnetic characterization of WFeB and identify it as a metallic d-wave altermagnet representative of a broader TiNiSi-type family. Neutron diffraction, Mössbauer spectroscopy, and magnetometry establish a collinear altermagnetic ordering confirmed by first-principles calculations. The electronic structure shows a nonrelativistic spin splitting of approximately 100 meV, but it also supports a strong spin-splitter transport response. This demonstrates that efficient spin-current generation can occur even with such modest band splitting. Symmetry analysis shows that selected film orientations permit deterministic switching of the Néel vector by current-induced staggered torques, enabling electrical control of a perpendicular spin-splitter response. These results establish WFeB and related TiNiSi-type antiferromagnets as a platform for electrically switchable charge-to-spin conversion driven by altermagnetic symmetry.

FOS: Physical sciences↗

NASA NTRS2019

Understanding Martian Alteration Processes by Comparing In-Situ Chemical Measurements from Multiple Landing Sites

Characterizing the history of aqueous activity at the martian surface has been an objective of the Mars Exploration Rovers (MER) and the Mars Science Laboratory (MSL). Although the geologic context of the three landing sites are different, comparisons across the datasets can provide greater insight than using data from one mission alone. The Alpha Particle X-ray Spectrometer (APXS) is common to all three rovers (Spirit at Gusev crater, Opportunity at Meridiani Planum, and Curiosity at Gale crater) and provides a consistent basis for these comparisons. Soil and Dust: Fine grained basaltic soils and dust are remarkably uniform in chemical composition across multiple landing sites. These similarities in the concentrations of major, minor, and a few trace elements (Fig. 1) are indicative of planet-wide consistency in the composition of source materials for the soils. S and Cl vary by a factor of two in the soil and dust, but there is no clear association with any bulk cation (e.g., no correlation between S and total Ca, Mg, or Fe in soils). These volatile elements, however, are clearly associated with the nanophase-ferric iron component in the soil established by Mössbauer spectroscopy [1,2]. S and Cl likely originated as acidic species from volcanic out-gassing and subsequently coalesced on dust and sand grain surfaces, possibly with an affinity towards Fe3+ sites. Importantly, given the mobility of S and Cl in aqueous exposures, soil samples maintaining the typical molar S/Cl ratio of ~3.7:1 indicate minimal interactions with liquid water after the addition of S and Cl. In contrast to this well-established baseline, soil samples have been discovered at all three landing sites with atypical S/Cl ratios (e.g., subsurface soils), indicative of a more complex aqueous history.

Yen, A. S.↗

NASA NTRS2020

Thermal Decomposition of the Murchison CM2 Carbonaceous Chondrite: Implications of Space Weathering Processes for Sample Return Missions

Primitive carbonaceous asteroids are the target bodies for the JAXA Hayabusa2 mission to Ryugu and the NASA OSIRIS-REx mission to Bennu. Both asteroids share spectral characteristics of CI/CM type carbonaceous chondrites. Ryugu, in particular, appears to have undergone thermal processing that has modified its spectral properties. The nature and extent of space weathering processes on the surfaces of Bennu and Ryugu are under active investigation using remote sensing data from the missions [4] and through laboratory studies on analog materials. The analog studies are needed in order to understand the mineralogical and chemical changes that occur in space weathered samples that give rise to the observed optical effects measured by remote-sensing and to prepare for the analysis of returned samples. The space weathering effects of micrometeorite impact and solar wind irradiation on primitive carbonaceous chondrites have been simulated by analog studies on the Murchison CM2 chondrite. We performed a coordinated mineralogical, chemical and spectroscopic study to examine in detail the effects of thermal metamorphism on Murchison samples as an analog to processes that may have occurred on Ryugu. The bulk measurements including X-ray diffraction (XRD), Mössbauer spectroscopy, UV-VIS-NIR spectroscopy, thermogravimetric analysis, and evolved gas analysis are reported in a companion paper. Here we report on our preliminary nanoscale mineralogical and chemical analyses of pre- and post-heated Murchison samples using multiple electron beam techniques to understand how the mineralogical, chemical, and physical characteristics of carbonaceous chondrites change with increasing thermal effects.

Lee, S.↗

NASA NTRSDate not supplied

Analysis of Samples from Asteroid Ryugu Returned by Hayabusa2

After returning to Earth in the winter of 2020, the samples from Cb-type asteroid Ryugu were stored under atmosphere-free conditions at the Extraterrestrial Materials Curation Center of ISAS/JAXA, and investigated for basic descriptions (sample imaging, weighing, etc.). They were distributed to six initial analysis teams in Japan in June 2021. The "Stone" team, in charge of analysis of coarse particles (>1 mm in size), conducted a series of analyses using a variety of techniques including reflectance spectra measurement, synchrotron-radiation three-dimensional elemental and mineralogical analysis, bulk elemental analysis using muon beam, Fe valence state measurement by XANES and Mössbauer spectroscopy, detailed mineralogical and petrological characterization by scanning and transmission electron microscopes. Physical and thermal properties of Ryiugu samples were measured to understand the response to shock and heating. In this talk, I would like to introduce summary of analysis results and what comes to be known about the formation and evolution of asteroid Ryugu.

Tomoki Nakamura↗

DOE OSTI2020

Formation of monomeric Sn(ii) and Sn(iv) perfluoropinacolate complexes and their characterization by 119 Sn Mössbauer and 119 Sn NMR spectroscopies

The synthesis and characterization of a series of Sn(II) and Sn(IV) complexes supported by the highly electron-withdrawing dianionic perfluoropinacolate (pinF) ligand are reported herein. Three analogs of [Sn IV (pin F ) 3 ] 2- with NEt 3 H + (1), K + (2), and {K(18C6)} + (3) counter cations and two analogs of [SnII(pinF)2]2- with K+ (4) and {K(15C5) 2 } + (5) counter cations were prepared and characterized by standard analytical methods, single-crystal X-ray diffraction, and 119 Sn Mössbauer and NMR spectroscopies. The six-coordinate SnIV(pinF) complexes display 119 Sn NMR resonances and 119 Sn Mössbauer spectra similar to SnO 2 (cassiterite). In contrast, the four-coordinate SnII(pinF) complexes, featuring a stereochemically-active lone pair, possess low 119 Sn NMR chemical shifts and relatively high quadrupolar splitting. Furthermore, the Sn(II) complexes are unreactive towards both Lewis bases (pyridine, NEt 3 ) and acids (BX 3 , Et 3 NH + ). Calculations confirm that the Sn(II) lone pair is localized within the 5s orbital and reveal that the Sn 5p x LUMO is energetically inaccessible, which effectively abates reactivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Lattice dynamics, sound velocities, and atomic environments of szomolnokite at high pressure

Complex mixtures of sulfates, silicates, and ice have been observed in a variety of planetary environments on Earth, Mars and the icy satellites of the solar system. Characterizing the properties of the corresponding compositional endmembers is important for understanding the interiors of a range of planetary bodies in which these phases are observed. To measure the electronic and vibrational properties of the pure ferrous iron endmember of the kieserite group, szomolnokite, (FeSO 4 ∙H 2 O), we have performed synchrotron 57 Fe nuclear resonant inelastic and forward scattering experiments in the diamond-anvil cell up to 14.5 GPa. This pressure range covers depths within Earth’s interior relevant to sulfur cycling in subduction zones and the range of pressures expected within icy satellite interiors. We find evidence of crystal lattice softening, changes in elastic properties, and changes in the electric field gradients of iron atoms associated with two structural transitions occurring within the experimental pressure range. Here we apply these findings to icy satellite interiors, including discussion of elastic properties, modeling of ice-sulfate aggregates, and implications for tidal observations.

58 GEOSCIENCES↗

DOE OSTI2023

Ironing out the transition metal contribution to the magnetism of the n = 3 members of the homologous series Pr n +1 M n Ge 3 n +1 (M = Fe, Co): Pr 4 Fe 3 Ge 10 vs. Pr 4 Co 3 Ge 10

The Ln n+1 M n X 3n+1 (Ln = lanthanide, M = transition metal, and X = tetrel) homologous series provides a platform to study collective phenomena in quantum materials. Here, in this work, we compare the crystal growth, structure, and magnetic properties of the n = 3 members of the Pr n+1 M n Ge 3n+1 (M = Fe, Co) analogues, Pr 4 Fe 3 Ge 10 (a = 4.3207 (10) Å, b = 35.523 (8) Å, c = 4.2982 (15) Å, and V = 659.7 (3) Å 3 ) and Pr 4 Co 3 Ge 10 (a = 4.3091 (12) Å, b = 35.750 (9) Å, c = 4.2807 (11) Å, and V = 659.4 (3) Å 3 ). We determined that the ideal flux growth conditions for each compound are highly dependent on the concentration of Sn flux and quench temperature. Pr 4 Fe 3 Ge 10 orders ferromagnetically at 10 K along the c-direction while Pr 4 Co 3 Ge 10 orders antiferromagnetically at 16 K along the b-direction. For both compounds, we observed a magnetic moment higher than that expected for only Pr 3+ ions (3.58 µ B /Pr), implying that the transition metal ions contribute to magnetic ordering (3.91, 3.48, and 3.69 µ B /Pr for Pr 4 Fe 3 Ge 10 , and 3.76, 4.04, and 3.83 µ B /Pr for Pr 4 Co 3 Ge 10 measured along the a-, b-, and c-directions, respectively). Moreover, the zero-field Mössbauer spectrum obtained at 4.2 K for Pr 4 Fe 3 Ge 10 demonstrates that the iron sites participate in magnetic ordering.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Boosting electrochemical reaction and suppressing phase transition with a high-entropy O3-type layered oxide for sodium-ion batteries

Complex phase transitions induced by interlayer slides in layered cathode materials lead to poor cycling stability and rate capability for sodium-ion batteries. Herein, we design and prepare a new six-component high-entropy oxide (HEO) layered cathode O3–Na(Fe 0.2 Co 0.2 Ni 0.2 Ti 0.2 Sn 0.1 Li 0.1 )O 2 to enable highly reversible electrochemical reaction and phase-transition behavior. The HEO cathode exhibits good cycling performance (capacity retention of ~81% after 100 cycles at 0.5C) and outstanding rate capability (capacity of ~81 mA h g –1 at 2.0C) due to the higher sodium diffusion coefficient (above 5.75 × 10 –11 cm 2 s –1 ) than most reported O3-type cathodes. Moreover, the high-entropy cathode has superior compatibility with the hard carbon anode and delivers a specific capacity of 90.4 mA h g –1 (energy density of ~267.5 W h kg –1 ). Ex situ X-ray diffraction proves that the high-entropy designing effectively suppresses the intermediate phase change to achieve reversible O3–P3 phase evolution, and in turn stabilizes the layered structure. X-ray absorption spectroscopy and Mössbauer spectrum of 57 Fe suggest that Ni 2+ /Ni 3.5+ , Co 3+ /Co 3.5+ , and part of Fe 3+ /Fe 3.5+ redox reaction contribute the charge compensation. Finally, the enhanced performance can be attributed to the disordered distribution of multi-component transition metals in HEO suppressing the ordering of electric charges and sodium vacancies, thereby inhibiting the interlayer slide and phase transition.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Absence of long-range magnetic order in Fe 1–δ Te 2 (δ ≈ 0.1) crystals

Transition metal dichalcogenides attract considerable attention due to variety of interesting properties, including long range magnetism in nanocrystals. Here we have investigated magnetic, thermal and electrical properties of FeTe 2 single crystal with iron vacancy defects. Magnetic measurements shows paramagnetic state and the absence of magnetic order with small anisotropy in magnetic susceptibility. Fe 3d orbitals are well hybridized, contributing to bad metal electrical resistivity. Observed thermal conductivity values below room temperature are rather low and comparable to high performance thermoelectric materials. Furthermore, our results indicate that FeTe 2 can form in highly defective marcasite crystal structure which can be exploited in future materials design.

36 MATERIALS SCIENCE↗