Samarium: from a distorted-fcc phase to melting under dynamic compression using in-situ x-ray diffraction.

Lattice and electronic structure interactions for f-electrons are fundamental challenges for lanthanide equation of state development. Difficulties in first-principles calculations, such as density functional theory (DFT), emphasize the need for well-characterized experimental data. Here, we measure in-situ x-ray diffraction of shocked samarium (Sm) and temperature along the Hugoniot for the first time, providing direct evidence for phase transitions.

Melting and density of MgSiO determined by shock compression of bridgmanite to 1254GPa.

The essential data for interior and thermal evolution models of the Earth and super-Earths are the density and melting of mantle silicate under extreme conditions. Here, we report an unprecedently high melting temperature of MgSiO at 500 GPa by direct shockwave loading of pre-synthesized dense MgSiO (bridgmanite) using the Z Pulsed Power Facility. We also present the first high-precision density data of crystalline MgSiO to 422 GPa and 7200 K and of silicate melt to 1254 GPa.