High-pressure structural systematics in samarium up to 222 GPa

DOI: 10.1103/PhysRevB.101.174109

Authors: S. E. Finnegan (The University of Edinburgh) , E. J. Pace (The University of Edinburgh) , C. V. Storm (The University of Edinburgh) , M. I. Mcmahon (The University of Edinburgh) , S. G. Macleod (AWE; The University of Edinburgh) , H.-P. Liermann (DESY) , K. Glazyrin (DESY)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Physical Review B , VOL 101

State: Published (Approved)
Published: May 2020
Diamond Proposal Number(s): 22350 , 20311

Abstract: 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.

Journal Keywords: Pressure effects; Structural properties; Lanthanides; Pressure techniques

Subject Areas: Materials, Physics


Instruments: I15-Extreme Conditions

Other Facilities: P02.2 at PETRA III

Added On: 28/05/2020 13:24

Discipline Tags:

Physics Hard condensed matter - structures Materials Science Metallurgy

Technical Tags:

Diffraction X-ray Powder Diffraction