A very intense effort has been made from the beginning of the program to build a target (and sample preparation LAB) for dynamic compression studies as well as to provide samples for diamond-anvil cells experiments. An important part of ERC's budget was thus devoted to the acquisition of equipment allowing the production of experimental units, which are referred to as "targets" for high-pressure experiments, each target being unique for a series of experiments requiring high flexibility of manufacturing equipment. The fabrication LAB is now operational and has several equipements such as a PVD chamber for metal and metal oxides deposition, a e-gun evaporation chamber, a plastic deposition unit, and several control and preparation tools such as a profilometer, ionic polishing equipment, microscope and UV gluing unit. The manufacture of our own targets started in April 2017. Each target has a unique architecture, whether it is the chemical nature of the layers that compose it, their thicknesses or the order in which the stacking is performed, as well as the nature of the supports. All of these variables mean that extensive development work is required before each production run, the iMPMC lab has then all equipment allowing a proper characterization of these samples/targets (SEM, FIB, TEM, x-ray diffraction and spectroscopy platforms). An article has been published about the fabrication of targets, inlcuding our own focus on specific targets for dynamic compression (Prencipe, I. et al. Targets for high repetition rate laser facilities: Needs, challenges and perspectives. High Power Laser Science and Engineering, 5. doi:10.1017/hpl.2017.18 2017).
High-pressure phase diagrams of Iron and Iron alloys (Fe-Si, Fe-O and Fe-C) have been studied up to 500 GPa pressures by the use of laser shock compression. For that purpose, we conducted X-ray diffraction at FEL facilities (LCLS and SACLA) as well as X-ray absorption spectroscopy at ESRF. These experiments are being exploited rigth now and several articles are in preparation. We have also performed high pressure and temperature experiments on SiC samples, combining laser heated diamond anvil cell and synchrotron X-ray diffraction. The obtained set of data provides information on the P T region between 30 – 205 GPa and 300 - 3500 K. The results show evidences of coexistence of SiC with Si or C, depending on the starting composition, without the appearance of intermediate compounds. Moreover, between 65 and 80 GPa, SiC undergoes a phase transition with the zinc blend structure (B3), typical of ambient conditions, replaced by the rock salt structure (B1). This phase transition corresponds to a change in the coordination of the atoms, and is accompanied by a 10% volume reduction. This work resulted in a publication in the Journal of Geophysical Research this year (Miozzi et al., J. Geophys. Res. Planets, 123. https://doi.org/10.1029/ 2018JE005582).
Other static compression experiments were performed at the ESRF (beamline ID27 for XRD experiments and beamline ID24 for XAS experiments). We determined melting temperature, the chemical composition of the eutectic point and the liquid density up to 150 GPa for Fe-C and Fe-O binary systems. We also determined the triple point fcc-hcp-liquid for pure Fe using X-ray Absorption Spectroscopy as a structural change diagnostic. Two articles have been published on this topic (Morard et al., Geophys. Res. Lett. 45. https:// doi.org/10.1029/2018GL079950; Morard et al., Earth and Planetary Science Letters 473. Elsevier B.V.: 94–103. doi:10.1016/j.epsl.2017.05.024).
