Superconductivity at 253 K in lanthanum–yttrium ternary hydrides
Superconductivity at 253 K in lanthanum–yttrium ternary hydrides
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DOI：
10.1016/j.mattod.2021.03.025
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发表时间：
2020-12
期刊：
影响因子：
24.2
通讯作者：
D. Semenok;I. Troyan;A. Kvashnin;A. Ivanova;M. Hanfland;A. Sadakov;O. Sobolevskiy;K. S. Pervakov-K.-S.-Pervak
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文献类型：
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作者：
D. Semenok;I. Troyan;A. Kvashnin;A. Ivanova;M. Hanfland;A. Sadakov;O. Sobolevskiy;K. S. Pervakov-K.-S.-Pervak
本文报道了在170-196 GPa的高压下，用氨硼烷激光加热p6.3 /mmc La-Y合金，合成了一系列镧钇三元氢化物。结果，我们发现了几种新的化合物：立方六氢化物（La， Y） h6和十氢化物（La， Y） h10，它们的最大临界温度为T C ~ 253 K，外推的上限临界磁场B C2(0)在183 GPa下高达135 T。电流-电压测量结果表明，（La， Y） h10在4.2 K下的临界电流密度jc为12-27.7 kA/ mm2，与NbTi和Nb 3sn等商用超导导线相当。（La， Y） h6和（La， Y） h10是三元高温超导氢化物的第一批例子。我们的实验表明，在最近发现的Im 3¯m-YH 6和Fm 3¯m-YH 10的结构中，部分金属原子可以分别被镧（~ 70%）和钇（~ 25%）取代，形成独特的三元超氢化物，其中包含金属包覆笼La@ H 24和Y@ H 32，这是Im 3¯m-YH 6和Fm 3¯m-YH 10所特有的。这项工作表明，纯形式的氢化物，如la6和yh10，在相对较低的压力下，可以在具有所需结构的超氢化物的固溶体中稳定下来。
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 P6 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/mm 2 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.