1,2Adrien Denoeud et al. (>10)*
Proceedings of the National Academy of Sciences 113, 7745-7749 Link to Article [doi:10.1073/pnas.1512127113]
1Laboratoire d’Utilisation de Lasers Intenses – CNRS, Ecole Polytechnique, Commissariat à l’Energie Atomique et aux Energies Alternatives, Université Paris-Saclay, F-91128 Palaiseau Cedex, France;
2Sorbonne Universités, Université Pierre et Marie Curie Paris 6, CNRS, Laboratoire d’Utilisation des Lasers Intenses, place Jussieu, 75252 Paris Cedex 05, France
*Find the extensive, full author and affiliation list on the publishers website
Investigation of the iron phase diagram under high pressure and temperature is crucial for the determination of the composition of the cores of rocky planets and for better understanding the generation of planetary magnetic fields. Here we present X-ray diffraction results from laser-driven shock-compressed single-crystal and polycrystalline iron, indicating the presence of solid hexagonal close-packed iron up to pressure of at least 170 GPa along the principal Hugoniot, corresponding to a temperature of 4,150 K. This is confirmed by the agreement between the pressure obtained from the measurement of the iron volume in the sample and the inferred shock strength from velocimetry deductions. Results presented in this study are of the first importance regarding pure Fe phase diagram probed under dynamic compression and can be applied to study conditions that are relevant to Earth and super-Earth cores.