Semenok, Dmitrii V., Troyan, Ivan A., Ivanova, Anna G., Kvashnin, Alexander G., Kruglov, Ivan A., Hanfland, Michael, Sadakov, Andrey V., Sobolevskiy, Oleg A., Pervakov, Kirill S., Lyubutin, Igor S., Glazyrin, Konstantin V., Giordano, Nico, Karimov, Denis N., Vasiliev, Alexander L., Akashi, Ryosuke, Pudalov, Vladimir M., and Oganov, Artem R.
[Display omitted] 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 P 6 3 /mmc La–Y alloys with ammonia borane. As a result, we discovered several novel compounds: cubic hexahydride (La,Y)H 6 and decahydrides (La,Y)H 10 with a maximum critical temperature T C ∼ 253 K and an extrapolated upper critical magnetic field B C2 (0) of up to 135 T at 183 GPa. The current–voltage measurements show that the critical current density J C in (La,Y)H 10 is 12–27.7 kA/mm2 at 4.2 K, which is comparable with that of commercial superconducting wires such as NbTi and Nb 3 Sn. (La,Y)H 6 and (La,Y)H 10 are among the first examples of ternary high- T C superconducting hydrides. Our experiments show that part of metal atoms in the structures of recently discovered Im 3 ¯ m -YH 6 and Fm 3 ¯ m -LaH 10 can be replaced with lanthanum (∼70%) and yttrium (∼25%), respectively, with the formation of unique ternary superhydrides containing metal-encapsulated cages La@H 24 and Y@H 32 , which are specific for Im 3 ¯ m -LaH 6 and Fm 3 ¯ m -YH 10. This work demonstrates that hydrides, unstable in pure form such as LaH 6 and YH 10 , may nevertheless be stabilized at relatively low pressures in solid solutions with superhydrides having the desired structure. [ABSTRACT FROM AUTHOR]