Figure 2
(a) Representative x-ray diffraction patterns for different solid, solid+liquid and liquid phases. At 0 GPa, the red dotted line is the simulated x-ray diffraction pattern for Sm-type ambient phase. At 23 and 29 GPa, dotted lines correspond to the Rietveld refined fitting result. (b) Rietveld refinement results at 29.1 GPa showing the observed and calculated patterns, reflection tick marks (blue vertical lines) and difference profiles (\(\Delta /\sigma \)) shown below the refinement curve) using dfcc, hR24 structure (R-3m). The structural parameters of a = 6.18 ± 0.05 Å, c = 15.36 ± 0.06 Å, and atomic coordinates of (0, 0, 0.251), and (0.509, -0.509, 0.244) were used for the dfcc phase. (c) Rietveld refinement result using the fcc (Fm-3m) phase. The structural parameters of a = 4.47 ± 0.06 Å, and atomic coordinates of (0, 0, 0) were used. The poor fitting results using the fcc structure clearly suggest that dfcc is indeed the stable phase.
