Dynamic X-ray diffraction observation of shocked solid iron up to 170 GPa

Adrien Denoeud (a,b), Norimasa Ozaki (c,d), Alessandra Benuzzi-Mounaix (a,b), Hiroyuki Uranishi (c), Yoshihiko Kondo (c), Ryosuke Kodama (c,d), Erik Brambrink (a,b), Alessandra Ravasio (a,b), Maimouna Bocoum (a,b), Jean-Michel Boudenne (a,b), Marion Harmand (e), François Guyot (e), Stephane Mazevet (f), David Riley (g), Mikako Makita (g), Takayoshi Sano (h), Youichi Sakawa (h), Yuichi Inubushi (i,j), Gianluca Gregori (k), Michel Koenig (a,b,l), and Guillaume Morard (e) “Dynamic X-ray diffraction observation of shocked solid iron up to 180 GPa”. Proc. Nat. Ac. Sc., 113, 28, 7745-7749

a-Laboratoire 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;

b-Sorbonne Universités, Université Pierre et Marie Curie Paris 6, CNRS, Laboratoire d’Utilisation des Lasers Intenses, place Jussieu, 75252 Paris Cedex 05, France;

c-Graduate School of Engineering, Osaka University, Osaka 5650871, Japan;

d-Photon Pioneers Center, Osaka University, Osaka 5650871, Japan;

e-Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités – Université Pierre et Marie Curie, CNRS, Muséum National d’Histoire Naturelle, Institut de Recherche pour le Développement, 75005 Paris, France;

f-Laboratoire Univers et Théories, Observatoire de Paris, CNRS, Université Paris Diderot, 92195 Meudon, France;

g-Centre for Plasma Physics, School of Maths & Physics, Queens University Belfast, Belfast BT7 1NN, Northern Ireland;

h-Institute of Laser Engineering, Osaka University, Osaka 5650871, Japan;

i-RIKEN SPring-8 Center, Hyogo 679-5148, Japan;

j-Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan;

k-Department of Physics, University of Oxford, Oxford OX13PU, United Kingdom;

l-Institute for Academic Initiatives, Osaka University, Osaka 565-0871, Japan

Edited by Vladimir E. Fortov, Russian Academy of Sciences, Moscow, and approved May 31, 2016 (received for review June 22, 2015)

Abstract
Investigation of the iron phase diagram under high pressure andn,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.

http://www.pnas.org/content/113/28/7745.abstract