LULI2000 - Exploring the phase diagram, melting and metallization of shocked GeO2 using x-ray diffraction (R. Torchio)
GeO2 is a very important material for earth scientist as a chemical and structural analogue of SiO2, a major component of earth’s interior, in particular the structure of glass GeO2 is a good model for liquid or molten SiO2. The phase diagram of crystalline and glass GeO2 has been investigated in a very limited pressure range (up to 70 GPa by x-ray diffraction in the diamond anvil cell and up to 160 GPa by dynamic compression coupled to VISAR diagnostics). Dynamic compression at LULI2000 allows us to obtain good quality planar shocks up to 4-5 Mbars coupled to x-ray diffraction, a well-adapted diagnostic to observe on solid/solid and solid/liquid transitions. We propose here to extend the P T phase diagram of GeO2 polymorphs, looking for any further phase transitions and for the melting. We will also look for GeO2 possible metallization which was recently observed in SiO2 in the warm dense matter range.
LULI2000 - S16-17 / 2018