title: Structural and valence changes of europium hydride induced by application of high-pressure H₂.
abstract: Europium hydride EuH(x), when exposed to high-pressure H₂, has been found to exhibit the following structural and valence changes: Pnma(x = 2, divalent) → P6₃/mmc(x = 2, 7.2-8.7 GPa) → I4/m(x > 2, 8.7-9.7 GPa) → I4/mmm(x > 2, 9.7 GPa-,trivalent). With a trivalent character and a distorted cubic fcc structure, the I4/mmm structure is the β phase commonly observed for other rare-earth metal hydrides. Our study clearly demonstrates that EuH(x) is no longer an irregular member of the rare-earth metal hydrides.
authors.affiliation: Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, Hyogo 679-5198, Japan. matsuoka@cqst.osaka-u.ac.jp
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authors.lastname: Matsuoka
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authors.lastname: Fujihisa
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authors.lastname: Hirao
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authors.lastname: Seto
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authors.lastname: Shimizu
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authors.lastname: Machida
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