Figure 2
Observed (points), calculated (line) and difference (lower trace) X-ray powder diffraction pattern for Rietveld refinement of a sample of NiSi quenched from 1223 K at 17.5 GPa (for details, see text). The upper set of tick marks shows the positions of the Bragg reflections from (top downwards) NiSi in the Pmmn phase, NiSi in the [epsilon]-FeSi phase and [alpha]-Al2O3 (from the sample capsule). The broad features in the difference trace, for example at 37°, probably correspond to back transformation of some of the NiSi to its ambient-pressure MnP structure (see text); the reflection markers for this MnP-structured phase (which was not included in the refinement) are shown below the difference pattern.  [article HTML]

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