High-Pressure Powder Diffraction Using an Image-Plate Area Detector

1994 ◽  
pp. 419-432
Author(s):  
Richard J. Nelmes ◽  
Malcolm I. McMahon
Keyword(s):  
High Pressure ◽  
Powder Diffraction ◽  
Area Detector ◽  
Image Plate ◽  
Plate Area

Angle-dispersive powder diffraction at high pressure using an image-plate area detector

1992 ◽  
Vol 8 (5-6) ◽  
pp. 677-684 ◽  
Author(s):  
R. J. Nelmes ◽  
M. I. Mcmahon ◽  
P. D. Hatton ◽  
R. O. Piltz ◽  
J. Crain ◽  
...  
Keyword(s):  
High Pressure ◽  
Powder Diffraction ◽  
Area Detector ◽  
Image Plate ◽  
Plate Area

High-Pressure Powder Diffraction Using an Image-Plate Area Detector

1993 ◽  
Vol 37 ◽  
pp. 419-432
Author(s):  
Richard J. Nelmes ◽  
Malcolm I. McMahon
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Phase Transitions ◽  
Powder Diffraction ◽  
Significant Progress ◽  
Area Detector ◽  
Recent Developments ◽  
Plate Area ◽  
Made In

Modern synchrotron sources, and recent developments in experimental techniques, are allowing significant: progress to be made at present in the quality of crystal-structure infonnation at high pressure. Though there are exciting prospects for single-crystal work, especially using Laue techniques, most of the recent advances have been made in powder diffraction. In any case, high-pressure diffraction studies often require powder techniques because single crystals fail to survive the large density changes that accompany many pressure-induced phase transitions. In this paper, we focus on angle-dispersive (AD) powder diffraction on synchrotron sources.

2-d data collection in high pressure powder diffraction studies-applications to semiconductors

1996 ◽  
Vol 14 (4-6) ◽  
pp. 277-286 ◽  
Author(s):  
M. I. McMahon ◽  
R. J. Nelmes ◽  
H. Liu ◽  
S. A. Belmonte
Keyword(s):  
High Pressure ◽  
Data Collection ◽  
Powder Diffraction

Evolution of Disordering in SiC under High Pressure High Temperature Conditions: In-situ Powder Diffraction Study

1998 ◽  
Vol 278-281 ◽  
pp. 612-617 ◽  
Author(s):  
Bogdan F. Palosz ◽  
Svetlana Stelmakh ◽  
Stanislaw Gierlotka ◽  
M. Aloszyna ◽  
Roman Pielaszek ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Temperature Conditions ◽  
High Pressure High Temperature

An imaging plate system for high‐pressure powder diffraction: The data processing side

1992 ◽  
Vol 63 (1) ◽  
pp. 700-703 ◽  
Author(s):  
R. O. Piltz ◽  
M. I. McMahon ◽  
J. Crain ◽  
P. D. Hatton ◽  
R. J. Nelmes ◽  
...  
Keyword(s):  
High Pressure ◽  
Data Processing ◽  
Powder Diffraction ◽  
Imaging Plate ◽  
Plate System

scholarly journals Isothermal equation of state and high-pressure phase transitions of synthetic meridianiite (MgSO4·11D2O) determined by neutron powder diffraction and quasielastic neutron spectroscopy

2017 ◽  
Vol 73 (1) ◽  
pp. 33-46 ◽  
Author(s):  
A. Dominic Fortes ◽  
Felix Fernandez-Alonso ◽  
Matthew Tucker ◽  
Ian G. Wood
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Equation Of State ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Neutron Powder Diffraction ◽  
Bulk Liquid ◽  
Icy Satellites ◽  
Neutron Spallation Source ◽  
Quasielastic Neutron

We have collected neutron powder diffraction data from MgSO4·11D2O (the deuterated analogue of meridianiite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. Our measurements, made using the PEARL/HiPr and OSIRIS instruments at the ISIS neutron spallation source, covered the range 0.1 < P < 800 MPa and 150 < T < 280 K. The refined unit-cell volumes as a function of P and T are parameterized in the form of a Murnaghan integrated linear equation of state having a zero-pressure volume V 0 = 706.23 (8) Å3, zero-pressure bulk modulus K 0 = 19.9 (4) GPa and its first pressure derivative, K′ = 9 (1). The structure's compressibility is highly anisotropic, as expected, with the three principal directions of the unit-strain tensor having compressibilities of 9.6 × 10−3, 3.4 × 10−2 and 3.4 × 10−3 GPa−1, the most compressible direction being perpendicular to the long axis of a discrete hexadecameric water cluster, (D2O)16. At high pressure we observed two different phase transitions. First, warming of MgSO4·11D2O at 545 MPa resulted in a change in the diffraction pattern at 275 K consistent with partial (peritectic) melting; quasielastic neutron spectra collected simultaneously evince the onset of the reorientational motion of D2O molecules with characteristic time-scales of 20–30 ps, longer than those found in bulk liquid water at the same temperature and commensurate with the lifetime of solvent-separated ion pairs in aqueous MgSO4. Second, at ∼ 0.9 GPa, 240 K, MgSO4·11D2O decomposed into high-pressure water ice phase VI and MgSO4·9D2O, a recently discovered phase that has hitherto only been formed at ambient pressure by quenching small droplets of MgSO4(aq) in liquid nitrogen. The fate of the high-pressure enneahydrate on further compression and warming is not clear from the neutron diffraction data, but its occurrence indicates that it may also be a rock-forming mineral in the deep mantles of large icy satellites.

Phase transitions in ReO3studied by high-pressure X-ray diffraction

2000 ◽  
Vol 33 (2) ◽  
pp. 279-284 ◽  
Author(s):  
J.-E. Jørgensen ◽  
J. Staun Olsen ◽  
L. Gerward
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Powder Diffraction ◽  
Ambient Pressure ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Pressure Phase ◽  
Related Phase

ReO3has been studied at pressures up to 52 GPa by X-ray powder diffraction. The previously observed cubicIm3¯ high-pressure phase was shown to transform to a monoclinic MnF3-related phase at about 3 GPa. All patterns recorded above 12 GPa could be indexed on rhombohedral cells. The compressibility was observed to decrease abruptly at 38 GPa. It is therefore proposed that the oxygen ions are hexagonally close packed above this pressure, giving rise to two rhombohedral phases labelled I and II. The zero-pressure bulk moduliBoof the observed phases were determined and the rhombohedral phase II was found to have an extremely large value of 617 (10) GPa. It was found that ReO3transforms back to thePm3¯mphase found at ambient pressure.

Neutron powder diffraction study of (ND4)2SeCl6 under high pressure

1997 ◽  
Vol 241-243 ◽  
pp. 466-468 ◽  
Author(s):  
O Yamamuro ◽  
K Okishiro ◽  
T Matsuo ◽  
T Ohta ◽  
Y Kume ◽  
...  
Keyword(s):  
High Pressure ◽  
Diffraction Study ◽  
Powder Diffraction ◽  
Neutron Powder Diffraction
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