Phase transitions in cerium at high pressures (up to 15 GPa) and high temperatures

The puzzle of the $ \gamma\to\alpha$ and other phase transitions in cerium

“…However, already in 1981 Antonova et al [23] found a dome-shaped curve of phase boundaries which was later confirmed by the work of Zhao and Holzapfel [24], and Tsiok and Khvostantsev [25]. In [25,26] the cerium phase diagram was studied in the region of high temperatures and pressures. There, the direct phase transition from the tetragonal phase () to the cubic -phase [25] and the transition in the opposite direction (т.е.…”

“…In [25,26] the cerium phase diagram was studied in the region of high temperatures and pressures. There, the direct phase transition from the tetragonal phase () to the cubic -phase [25] and the transition in the opposite direction (т.е. ) were found at pressures 7.1 GPa (T735 K) and 7.2 GPa (T800 K) [24,26] (see Fig.1).…”

“…The opposite viewpoint is represented by the authors of Refs. [35,25]. They argue that if at pressure 5 GPa these two phases (' and '') coexist, then at pressures above 7 GPa the ''-Ce fraction disappears while '-Ce is present up to 13 GPa.…”

“…[2], -'-'' boundaries (corresponding to the directions ', '' and ''') from Ref. [25], the boundary between  and  phases from Ref. [26], the refined critical point of the  transition is from Ref.…”

“…[70]. The region of phase ambiguity corresponds to the mixture of phases (, ', '' and ), with the percentage depending on the P-T trajectory leading to a P-T point [25].…”