Structural Investigation of Ternary Polyhydrides of Light Elements

Light elements are the most promising in terms of increasing the critical temperature of superconductivity in polyhydrides. Study of promising hydrides of these elements, such as MgH6, CaMgH12, MgYH12, CaYH12 and Li2MgH16, is quite difficult due to the weak X-ray scattering cross section on light atoms, as well as due to small size of sample (20-30 μm) at pressure of 2 Mbar. Nevertheless, increasing the beam intensity at the ESRF and improving the equipment at the ID27 station open up opportunities for successful implementation of this joint project of the Jilin University and HPSTAR collaboration. Within this work, we plan to investigate the structure of ternary hydrides of light elements: magnesium-calcium, magnesium-yttrium, calcium-yttrium, lithium-magnesium, at pressures of 170-200 GPa using powder (single-crystal when possible) X-ray diffraction in high-pressure diamond anvil cells (DACs) combined with X-ray fluorescence to establish the exact composition of microsamples.