High-pressure single-crystal neutron diffraction

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Date
2017-02-03
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Institute of Physics
Abstract
High-pressure neutron diffraction is always challenging, but it can offer several advantages over high-pressure X-ray diffraction to make meeting those challenges worthwhile. In addition to the usual higher sensitivity to low-X elements, notably hydrogen, and to magnetic moments, the low absorption by many pressure cell materials can yield greater reciprocal space coverage for single crystals. The low scattering power usually requires considerably larger sample volumes than with X-rays, but for the same reason the cell-wall materials can be quite thick. Common cell designs include He-gas cells and simple clamp cells, opposed piston cells (e.g. Bloch, McWhan), opposed-anvil cells (e.g. diamond anvil cell, Paris-Edinburgh cell), and multi-anvil cells, each adapted to sample volume, accessibility, pressure, and other external parameters, especially temperature, that suit the scientific question of interest. State-of-the-art experiments using each cell type will be described. A special challenge in high-pressure diffraction is to perform neutron and X-ray experiments on the same material under the same conditions. Previously, this meant using different cells and samples with achieving identical pressures largely a hit-or-miss affair. This has all changed with the recent demonstration on KOALA on the OPAL research reactor that modern neutron Laue diffraction can be performed on the same sample in the same diamond-anvil cell as used for laboratory X-ray experiments [1].
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Keywords
Pressure range mega pa 10-100, Crystals, Neutron diffraction, Scattering, Materials, Hydrogen, Magnetic moments, Absorption, Reactor cells, Pistons
Citation
McIntyre, G. J., Binns., J., & Parsons, S. (2017). High-pressure single-crystal neutron diffraction. Poster presented to the 41st Annual Condensed Matter and Materials Meeting, Charles Sturt University, Wagga Wagga, NSW, Australia, 31st January - 3rd February 2017, (pp. 92). Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2017/Wagga_2017_Conference_Handbook.pdf