Strategies for reducing preferred orientation and strain in powder samples for high-pressure synchrotron X-ray diffraction in diamond-anvil cells

Tschauner, Oliver; McClure, Jason; Nicol, Malcolm

doi:10.1107/s0909049505023575

Cited by 6 publications

(6 citation statements)

References 11 publications

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“…Considering the literature reports on the stress-induced peak splitting for non ice systems [19][20][21][22][23][24][25] and for ice VII, 16 it is reasonable to suggest that the peak splitting observed in our study is a result of strain created during water-to-ice transformation. Indeed, stresses could be expected when growing ice crystals met at the interface with each other or a container wall, because water-to-ice transformation is accompanied by an approximately 10% volume increase.…”

Section: Resultsmentioning

confidence: 73%

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

et al. 2009

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Simple aqueous systems, i.e., phosphate-glycine buffers and pure water, were studied at subambient temperatures by X-ray difractometry using a high-intensity synchrotron radiation source at the Advanced Photon Source of Argonne National Laboratory. Complex X-ray diffraction (XRD) patterns, with two or more poorly resolved peaks in place of each of the four diagnostic peaks of hexagonal ice, 100, 002, 101, and 102, referred as "splitting", were observed in the majority of cases. The splitting of up to 0.05 A (d-spacing) was detected for 100, 002, and 101 peaks, whereas 102 peak was less affected. Deformation of the lattice of hexagonal ice, probably due to local stress created on the ice/ice or ice/container interface during water-to-ice transformation, is proposed as a possible mechanism for the observed splitting of XRD peaks. Using molecular modeling, it was estimated that the observed shifts in the peak positions are equivalent to applying a hydrostatic pressure of 2-3 kbars. The splitting can be used to quantify stresses during freezing, which could improve our understanding of the role of water-to-ice transformation on the destabilization of proteins and other biological systems.

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Section: Resultsmentioning

confidence: 73%

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

et al. 2009

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“…Inaccuracies of the relative peak intensities are a frequent problem when measuring powder XRD in a diamond anvil cell due to the small sample mass and the presence of preferred orientations. 21 Therefore, the atomic positions of the pressure induced phase may be best determined from density functional theory calculations as reported previously, 10 rather than from refinements of XRD data. …”

Section: B X-ray Diffractionmentioning

confidence: 99%

Evidence for two distinct superconducting phases inEuBiS2Funder pressure

et al. 2015

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We present a pressure study of the electrical resistivity, ac magnetic susceptibility and powder x-ray diffraction (XRD) of the recently discovered BiS2-based superconductor EuBiS2F. At ambient pressure, EuBiS2F shows an anomaly in the resistivity at around T0 ≈ 280 K and a superconducting transition at Tc ≈ 0.3 K. Upon applying hydrostatic pressure, there is little change in T0 but the amplitude of the resistive anomaly is suppressed, whereas there is a dramatic enhancement of Tc from 0.3 K to about 8.6 K at a critical pressure of pc ≈ 1.4 GPa. XRD measurements confirm that this enhancement of Tc coincides with a structural phase transition from a tetragonal phase (P 4/nmm) to a monoclinic phase (P 21/m), which is similar to that observed in isostructural LaO0.5F0.5BiS2. Our results suggest the presence of two different superconducting phases with distinct crystal structures in EuBiS2F, which may be a general property of this family of BiS2-based superconductors.

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“…microstrain increases with higher pressures and decreases after laser heating. The phenomenon of reflections narrowing after laser heating of a given sample in a DAC as a result of stress relaxation is known as laser annealing (Winkler et al, 2009;Tschauner et al, 2005). In this study, this effect could be shown quantitatively for the first time using microstrain parameters obtained from a Rietveld analysis.…”

Section: Figurementioning

confidence: 77%

Decomposition of W(CO)₆at high pressures and temperatures

et al. 2011

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The decomposition of hexacarbonyltungsten, W(CO)6, has been studied. The decomposition was induced by heating W(CO)6 in an autoclave at 523 K and pressures up to 1.8 MPa, and by laser heating in a diamond anvil cell at pressures between 5 and 18 GPa. The products have been characterized using synchrotron X‐ray diffraction, pair distribution function analysis, Raman spectroscopy and scanning electron microscopy. Decomposition in the autoclave at the lower pressures resulted in the formation of a metastable tungsten carbide, W2C, with an average particle size of 1–2 nm, and an unidentified nanocrystalline tungsten oxide and nanocrystalline graphite with average particle sizes of 1–2 and 11 nm, respectively. The existence of nanocrystalline graphite was deduced from micro‐Raman spectra and the graphite particle size was extracted from the intensities of the Raman modes. The high‐pressure decomposition products obtained in the diamond anvil cell are the monoclinic tungsten oxide phase WO2 and the high‐pressure phase W3O8(I). The approximate average size of the graphite particles formed here was 6–8 nm. The bulk modulus of W(CO)6 is B0≃ 13 GPa.

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Strategies for reducing preferred orientation and strain in powder samples for high-pressure synchrotron X-ray diffraction in diamond-anvil cells

Cited by 6 publications

References 11 publications

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

Evidence for two distinct superconducting phases inEuBiS2Funder pressure

Decomposition of W(CO)₆at high pressures and temperatures

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Strategies for reducing preferred orientation and strain in powder samples for high-pressure synchrotron X-ray diffraction in diamond-anvil cells

Cited by 6 publications

References 11 publications

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

Synchrotron X-ray Diffraction Investigation of the Anomalous Behavior of Ice During Freezing of Aqueous Systems

Evidence for two distinct superconducting phases inEuBiS2Funder pressure

Decomposition of W(CO)6at high pressures and temperatures

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Decomposition of W(CO)₆at high pressures and temperatures