Synchrotron x-ray spectroscopy studies of valence and magnetic state in europium metal to extreme pressures

Journal Article · Tue May 22 04:00:00 EDT 2012 · Physics Review B

DOI:https://doi.org/10.1103/PhysRevB.85.205134· OSTI ID:1045823

Bi, W; Souza-Neto, N M; Haskel, D; Fabbris, G; Alp, E E; Zhao, J; Hennig, R G; Abd-Elmeguid, M M; Meng, Y; McCallum, Ralph W; Dennis, Kevin; Schilling, J S

In order to probe the changes in the valence state and magnetic properties of Eu metal under extreme pressure, x-ray absorption near-edge spectroscopy, x-ray magnetic circular dichroism, and synchrotron Mössbauer spectroscopy experiments were carried out. The Mössbauer isomer shift exhibits anomalous pressure dependence, passing through a maximum near 20 GPa. Density functional theory has been applied to give insight into the pressure-induced changes in both Eu's electronic structure and Mössbauer isomer shift. Contrary to previous reports, Eu is found to remain nearly divalent to the highest pressures reached (87 GPa) with magnetic order persisting to at least 50 GPa. These results should lead to a better understanding of the nature of the superconducting state found above 75 GPa and of the sequence of structural phase transitions observed to 92 GPa.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-07CH11358
• OSTI ID: 1045823
• Report Number(s): IS-J 7708
• Journal Information: Physics Review B, Journal Name: Physics Review B Vol. 85; ISSN 1098-0121
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE