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Title: Metallization and superconductivity in the hydrogen-rich ionic salt BaReH 9

BaReH 9 is an exceedingly high hydrogen content metal hydride that is predicted to exhibit interesting behavior under pressure. The high-pressure electronic properties of this material were investigated using diamond-anvil cell electrical conductivity techniques to megabar (100 GPa) pressures. The measurements show that BeReH 9 transforms to a metal and then superconductor above 100 GPa with a maximum T c near 7 K. The occurrence of superconductivity is confirmed by the suppression of the resistance drop on application of magnetic fields. The transition to the metallic phase is sluggish, but is accelerated by laser irradiation. Raman scattering and x-ray diffraction measurements, used to supplement the electrical measurements, indicate that the Ba-Re sublattice is largely preserved on compression at the conditions explored, but there is a possibility that hydrogen atoms are gradually disordered under pressure. This is suggested from sharpening of peaks of Raman spectroscopy and x-ray diffraction by heat treatment as well as temperature dependence of resistance under pressure. The data suggest that the transition to the superconducting state is first order. Furthermore, the possibility that the transition is associated with the breakdown of BeReH 9 is discussed.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1]
  1. Carnegie Institution of Washington, Washington, D.C. (United States)
  2. Univ. of Nevada, Reno, NV (United States)
Publication Date:
Grant/Contract Number:
NA0002006
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 119; Journal Issue: 32; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Carnegie Institution of Washington, Washington, D.C. (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1335842