High-pressure studies of lanthanum-yttrium ternary superhydrides*

The discovery of near room temperature superconductivity in LaH₁₀ and YH₉ confirmed the theoretical predictions that these hydrogen-rich metal hydrides are superconductors with critical temperature T_c in the vicinity of room temperature. Recent experimental and theoretical results for ternary hydrides have opened further investigations of room-temperature superconductivity, including optimizing doping in La-based hydrides. In this study, the hydrogen-rich lanthanum-yttrium ternary hydrides (La_1-nY_nH_x) were synthesized using ammonia borane (NH₃BH₃) as the hydrogen source. The results include documenting ~10% yttrium doped lanthanum superhydrides at 165 GPa by pulsed laser heating. Powder x-ray diffraction of the laser-heated samples has been used to confirm the formation of La-Y superhydrides.