Superconductivity at 253 K in lanthanum-yttrium ternary hydrides

Materials Today. 2021. Vol. 48. No. 15. P. 18–28.

Semenok D. V., Troyan I. A., Ivanova A. G., Kvashnin А. G., Hanfland M., Sadakov A. V., Sobolevskiy O. A., Pervakov K. S., Karimov D., Vasiliev A., Gavriliuk A. G., Lyubutin I. S., Akashi R., Vladimir M. Pudalov, Oganov A. R.

Here we report the high-pressure synthesis of a series of lanthanum–yttrium ternary hydrides obtained at pressures of 170–196 GPa via the laser heating of La–Y alloys with the ammonia borane: cubic hexahydride (La,Y)H6 and decahydrides (La,Y)H10 with a maximum TC ~ 253 K, an extrapolated upper critical magnetic field BC2(0) up to 135 T at 183 GPa, and a critical current density JC above 2500 A/mm2 at 4.2 K. Our experiments show that a part of the atoms in the structures of recently discovered 𝐼𝑚3̅𝑚-YH6 and 𝐹𝑚3̅𝑚-LaH10 can be replaced with lanthanum (~70%) and yttrium (~25%), respectively, with a formation of unique ternary superhydrides containing incorporated LaH24 and YH32 which are specific for 𝐼𝑚3̅𝑚-LaH6 and 𝐹𝑚3̅𝑚-YH10. This work demonstrates that hydrides, unstable in a pure form, may nevertheless be stabilized at relatively low pressures in solid solutions with superhydrides having the same structure

Keywords: high temperature superconductivity, высокотемпературная сверхпроводимость, hydrides, сверхвысокие давления, гидриды, superhigh pressures