High-pressure structural systematics in samarium up to 222 GPa
High-pressure structural systematics in samarium up to 222 GPa
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DOI：
10.1103/physrevb.101.174109
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发表时间：
2020-05-15
影响因子：
3.7
通讯作者：
Glazyrin, K.
中科院分区：
文献类型：
--
作者：
Finnegan, S. E.;Pace, E. J.;Glazyrin, K.
在222 GPa压力下对金属钐进行了角色散X射线粉末衍射实验。在50 GPa下观察到Sm型（hR 9）→ dhcp（hP4）→ fcc（cF 4）→畸变fcc（hR 24）→ hP 3跃迁序列。在93 GPa以上的高压相的结构，以前报道为具有空间群C2/m的单斜晶系结构，被发现是正交晶系，空间群Fddd，每个晶胞有8个原子（Pearson记法中的oF 8）。这种结构与高压下Am、Cm和Cf中发现的结构相同。钐的状态方程的分析揭示了hP 3和oF 8相的可压缩性的显著变化，其中oF 8相的可压缩性是“常规”金属的。
Angle-dispersive x-ray powder diffraction experiments have been performed on samarium metal up to 222 GPa. Up to 50 GPa we observe the Sm type (hR9) -> dhcp (hP4) -> fcc (cF4) -> distorted fcc (hR24) -> hP3 transition sequence reported previously. The structure of the high-pressure phase above 93 GPa, previously reported as having a monoclinic structure with space group C2/m, is found to be orthorhombic, space group Fddd, with eight atoms per unit cell (oF8 in Pearson notation). This structure is the same as that found in Am, Cm, and Cf at high pressures. Analysis of samarium's equation of state reveals marked changes in compressibility in the hP3 and oF8 phases, with the compressibility of the oF8 phase being that of a "regular" metal.