Polymorphic Transformation in Ytterbium

Abstract

The purpose of this Letter is to report the discovery of a polymorphic transformation in Yb and to provide a brief discussion of its significance in relation to recent high-pressure studies. The transformation, $\ensuremath{\beta}(\mathrm{fcc})\ensuremath{\leftrightarrow}\ensuremath{\alpha}(\mathrm{hcp})$, is martensitic, the $\ensuremath{\alpha}$ phase being the stable form at 1 atm below \ensuremath{\sim}270\ifmmode^\circ\else\textdegree\fi{}K. The slope of the $\frac{\ensuremath{\alpha}}{\ensuremath{\beta}}$ equilibrium boundary, ${(\frac{d{T}_{\ensuremath{\alpha},\ensuremath{\beta}}}{\mathrm{dP}})}_{{270}^{\ensuremath{\circ}},1 \mathrm{atm}}$, is (-23\ifmmode\pm\else\textpm\fi{}8)\ifmmode^\circ\else\textdegree\fi{}K/kbar.