POWGEN: rebuild of a third-generation powder diffractometer at the Spallation Neutron Source

Huq, Ashfia; Kirkham, Melanie J.; Peterson, Peter F.; Hodges, J. P.; Whitfield, Pamela S.; Page, Katharine; Hügle, Thomas; Iverson, Erik B.; Parizzi, A.; Rennich, George Q

doi:10.1107/s160057671901121x

Cited by 70 publications

(70 citation statements)

References 36 publications

(30 reference statements)

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“…Neutron powder diffraction data were collected using the Spallation Neutron Source (SNS) POWGEN diffractometer at Oak Ridge National Laboratory. 48 Approximately 3 g of sample was loaded into an 8 mm diameter cylindrical vanadium sample can. Using a center wavelength of 0.8 Å with a d -spacing from 0.2 to 6.0 Å, we collected data for ∼3 h in the high-resolution mode at each temperature.…”

Section: Experimental Methodsmentioning

confidence: 99%

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂

et al. 2020

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Strategies to enhance ionic conductivities in solid electrolytes typically focus on the effects of modifying their crystal structures or of tuning mobile-ion stoichiometries. A less-explored approach is to modulate the chemical bonding interactions within a material to promote fast lithium-ion diffusion. Recently, the idea of a solid-electrolyte inductive effect has been proposed, whereby changes in bonding within the solid-electrolyte host framework modify the potential energy landscape for the mobile ions, resulting in an enhanced ionic conductivity. Direct evidence for a solid-electrolyte inductive effect, however, is lacking—in part because of the challenge of quantifying changes in local bonding interactions within a solid-electrolyte host framework. Here, we consider the evidence for a solid-electrolyte inductive effect in the archetypal superionic lithium-ion conductor Li 10 Ge 1– x Sn x P 2 S 12 . Substituting Ge for Sn weakens the {Ge,Sn}–S bonding interactions and increases the charge density associated with the S 2– ions. This charge redistribution modifies the Li + substructure causing Li + ions to bind more strongly to the host framework S 2– anions, which in turn modulates the Li + ion potential energy surface, increasing local barriers for Li + ion diffusion. Each of these effects is consistent with the predictions of the solid-electrolyte inductive effect model. Density functional theory calculations predict that this inductive effect occurs even in the absence of changes to the host framework geometry due to Ge → Sn substitution. These results provide direct evidence in support of a measurable solid–electrolyte inductive effect and demonstrate its application as a practical strategy for tuning ionic conductivities in superionic lithium-ion conductors.

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Section: Experimental Methodsmentioning

confidence: 99%

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂

et al. 2020

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“…PND data were collected at RT using the constant-wavelength diffractometer PUS (λ =1.555 Å) at the JEEP II reactor (Kjeller, Norway) [26] and the time-of-flight (TOF-PND) instrument POWGEN at SNS (Oak Ridge, UK) [27]. The sample was loaded in vanadium cans with a diameter of 6 mm (PUS) or 3 mm (POWGEN).…”

Section: Methodsmentioning

confidence: 99%

Structure and water uptake in BaLnCo2O6−δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy)

et al. 2020

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The structure of BaLnCo2O6-δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy) is was studied by the means of synchrotron radiation powder X-ray diffraction, neutron powder diffraction and Transmission Electron Microscopy (TEM), while water uptake properties were analysed with the use of thermogravimetry (TG) and water adsorption isotherms. The structure refinement revealed that the dominant phase in all compositions was orthorhombic with an ordering of the A-site cations along the c-axis and ordering of oxygen vacancies along the b-axis, which was also directly evidenced by TEM. It was shown that both unit cell volume and average Co-oxidation state at room temperature decrease linearly with decreasing Ln radius. TG water uptake experiments in humidified N2-O2 gas mixture at 300°C revealed that among all compositions, only BaLaCo2O6-δ and BaGdCo2O6-δ exhibit significant water uptake. Surface water adsorption studies showed that the α, a normalised parameter reflecting the surface hydrophilicity, mostly independently of Ln radius was close to 0.5, which means that the surface is neither hydrophobic nor hydrophilic. The results indicated that water uptake observed at 300 °C is a bulk process, which cannot be described by standard hydration/hydrogenation reaction and it is related to the layered structure of the perovskite lattice and characteristic to La or Gd being present in the lattice.

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“…Neutron powder diffraction data were collected at 300 K, 200 K, 150 K, 50 K and 10 K at the POWGEN diffractometer [12] at the Spallation Neutron Source at Oak Ridge National Laboratory on 1.5 g of polycrystalline powder. Patterns at all temperatures were collected using a center wavelength of the neutron packet of 2.665Å, and additional patterns using a center wavelength of 0.8Å were collected at 300 K and 10 K. The longer wavelength data provides extremely high resolution and sensitivity at low Q, while the shorter wavelength data provides a much larger Q range.…”

Section: Methodsmentioning

confidence: 99%

Evolution of noncollinear magnetism in magnetocaloric MnPtGa

Cooley

Bocarsly

Schueller

et al. 2020

Phys. Rev. Materials

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MnPtGa crystallizes in the hexagonal Ni2In structure type in space group P 63/mmc, and has been reported to display a ferromagnetic Curie temperature near 220 K. Here we find a transition near TC = 236 K to a ferromagnetic state, albeit with a reduced moment from what is expected for collinear ordering. The peak magnetocaloric entropy change was determined to be ∆SM = −1.9 J kg −1 K −1 for an applied magnetic field of H = 5 T at the ferromagnetic ordering temperature. Magnetostructural coupling manifests as a change in the slope of the thermal expansion coefficients of the c lattice parameter near TC , with a negative spontaneous volume magnetostriction; ω = −300 ppm at 190 K. Neutron powder diffraction studies of the magnetic ground state reveal an evolution in complexity as temperature decreases: from a ferromagnet, to a canted antiferromagnet, to the eventual formation of a spin-density wave state at low temperatures.

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POWGEN: rebuild of a third-generation powder diffractometer at the Spallation Neutron Source

Cited by 70 publications

References 36 publications

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂

Structure and water uptake in BaLnCo2O6−δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy)

Evolution of noncollinear magnetism in magnetocaloric MnPtGa

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POWGEN: rebuild of a third-generation powder diffractometer at the Spallation Neutron Source

Cited by 70 publications

References 36 publications

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li10Ge1–xSnxP2S12

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li10Ge1–xSnxP2S12

Structure and water uptake in BaLnCo2O6−δ (Ln =La, Pr, Nd, Sm, Gd, Tb and Dy)

Evolution of noncollinear magnetism in magnetocaloric MnPtGa

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Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂

Evidence for a Solid-Electrolyte Inductive Effect in the Superionic Conductor Li₁₀Ge_1–xSn_xP₂S₁₂