Determination of O and Si exsolution during the crystallization of iron at planetary cores conditions determined using X-ray Absorption Spec

Planetary cores are constituted of iron alloyed with lighter elements (S, C, O, Si or H). Understanding the phase diagrams as well as the physical properties of these alloys under extreme conditions is crucial to model the thermal evolution and the dynamics of core crystallization, at the origin of the magnetic field. In the present proposal, we plan to use LCF to obtain quantitative composition from XAS spectra acquired at high pressure in the temperature quenched samples, employing the laser-heating set-up available on ID24 DCM. This will enable us to determine binary or ternary phase diagrams under extreme conditions.