Hematite phase diagram under laser shock compression

International audienceUntil recently, iron oxides were assumed to comprise only FeO, Fe3O4, and Fe2O3. However, static compression experiments have demonstrated the existence of new iron oxide stoichiometries at high pressure and temperature such as FeO2 [1], Fe4O5 [2], Fe5O6 [3], Fe13O19 [4]. These discoveries, with the wide variety of iron oxides phases existing at high pressure [5], highlight the complexity of iron-oxygen phase diagram at extreme condition. In this context, measurements of physical properties, phase transition processes and phase diagrams of Fe-O systems with laser shock compression techniques offer opportunities to extend the actual pressure and temperature ranges of such studies. Here, we will present main results from a laser shock experiment at the ID24 ESRF beamline using time-resolved X-ray absorption measurement on Fe2O3 samples. In addition, we will show results from a recent experiment performed at LULI 2000 to measure the equation of state and calculate sound velocities along the Fe2O3 Hugoniot and above 500GPa. [1] Hu2016 [2] Lavina 2011 [3] Lavina 2015 [4] Merlini 2015 [5] Bykova 201