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- Nikiforova, Yulia A., et al.
(författare)
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Crystal structure and phase transitions at high pressures in the superconductor FeSe0.89S0.11
- 2021
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 860
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Tidskriftsartikel (refereegranskat)abstract
- We report on the structural phase transitions in the FeSe0.89S0.11 superconductor with T-C = 11 K observed by powder synchrotron X-ray diffraction at high pressures up to 18.5 GPa under compression and decompression modes. It was found that at ambient pressure and room temperature, FeSe0.89S0.11 has a tetragonal structure (space group NM). Under compression, in the region of 10 GPa, a phase transition from the tetragonal into the orthorhombic structure (sp. gr . Pnma) is observed, which persists up to 18.5 GPa. Our results strongly suggest that, at decompression, as the applied pressure decreases to 6 GPa and then is completely removed, most of the sample recrystallizes into the hexagonal phase of the structural type NiAs (sp. gr . P6(3)/mmc). However, the other part of the sample remains in the high pressure orthorhombic phase (sp. gr . Pnma), while the tetragonal phase (sp. gr . P4/n) is not restored. These observations illustrate a strong hysteresis of the structural properties of FeSe0.89S0.11 during a phase transition under pressure. (C) 2020 Elsevier B.V. All rights reserved.
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