Structural and valence changes of europium hydride induced by application of high-pressure H₂

Phys Rev Lett. 2011 Jul 8;107(2):025501. doi: 10.1103/PhysRevLett.107.025501. Epub 2011 Jul 5.

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.