학술논문
Samarium: from a distorted-fcc phase to melting under dynamic compression using in-situ x-ray diffraction.
Document Type
Article
Author
Source
Subject
*EQUATIONS of state
*X-ray diffraction
*SAMARIUM
*MELTING
*DIAMOND anvil cell
*PHASE transitions
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Language
ISSN
2045-2322
Abstract
Lattice and electronic structure interactions for f-electrons are fundamental challenges for lanthanide equation of state development. Difficulties in first-principles calculations, such as density functional theory (DFT), emphasize the need for well-characterized experimental data. Here, we measure in-situ x-ray diffraction of shocked samarium (Sm) and temperature along the Hugoniot for the first time, providing direct evidence for phase transitions. We report direct evidence of a distorted fcc (dfcc) phase at 23 GPa. Shocked samarium melts from the dfcc phase starting at 33 GPa (1333 K), with complete melt at 40 GPa (1468 K). Previous work indicated shock melt at 27 GPa (1200 K), underscoring the significance of x-ray measurements for detecting phase transitions. Interestingly, our observed melting is in sharp contrast with the melting reported by a diamond anvil cell study. These experimental data can tightly constrain first principles calculations and serve as key touchstones for equation of state modeling. [ABSTRACT FROM AUTHOR]