论文标题
在灯笼yttrium三元氢化物中253 K处的超导性
Superconductivity at 253 K in lanthanum-yttrium ternary hydrides
论文作者
论文摘要
多氢化物提供了有趣的视角，作为高温超导体。在这里，我们报告了一系列Lanthanum-Yttrium ternary Hydrides的高压合成：立方六氢化盐$（la，y）H_ {6} $，具有临界温度$ t_ {c} $ t_ {c} $ = 237 +/- 5 k和decahydrides $（la y）$ and $ t y}在183 GPA时，外推上临界磁场$ b_ {c2（0）} $最高$ {135 t} $。这是三元高$ t_ {c} $超导氢化物的第一个例子之一。我们的实验表明，最近发现的$ {im3m} $ - $ yh_ {6} $和$ {fm3m} $ - $ lah_ {10} $可以用lanthanum（〜70％）和Yttrium（〜25％）替换为独特的ternary ternary ternary ternary， $ la@h_ {24} $和$ y@h_ {32} $，特定于$ {im3m} $ - $ lah_ {6} $和$ {fm3m3m} $ - $ yh_ {10} $。通过激光加热$ p6_ {3} $$ {/mmc} $ lanthanum-yttrium合金在2000 k以上的温度下于2000 k。 $（la，y）h_ {6} $。电流电压测量表明，关键电流密度$ j_ {c} $ in $（la，y）h_ {10} $可能超过$ 2500 a/mm^{2} $在4.2 k时，这与商业超导电线（例如aS $ {nbti} $ nbti} $，$ nb_} $ a} $ {3} $ {3}然而，以纯形形式不稳定的氢化物可能在具有相同结构相同结构的固体溶液中以相对较低的压力稳定。
Polyhydrides offer intriguing perspectives as high-temperature superconductors. Here we report the high-pressure synthesis of a series of lanthanum-yttrium ternary hydrides: cubic hexahydride $(La,Y)H_{6}$ with a critical temperature $T_{C}$ = 237 +/- 5 K and decahydrides $(La,Y)H_{10}$ with a maximum $T_{C}$ ~${253 K}$ and an extrapolated upper critical magnetic field $B_{C2(0)}$ up to ${135 T}$ at 183 GPa. This is one of the first examples of ternary high-$T_{C}$ superconducting hydrides. Our experiments show that a part of the atoms in the structures of recently discovered ${Im3m}$-$YH_{6}$ and ${Fm3m}$-$LaH_{10}$ can be replaced with lanthanum (~70 %) and yttrium (~25 %), respectively, with a formation of unique ternary superhydrides containing incorporated $La@H_{24}$ and $Y@H_{32}$ which are specific for ${Im3m}$-$LaH_{6}$ and ${Fm3m}$-$YH_{10}$. Ternary La-Y hydrides were obtained at pressures of 170-196 GPa via the laser heating of $P6_{3}$${/mmc}$ lanthanum-yttrium alloys in the ammonia borane medium at temperatures above 2000 K. A novel tetragonal $(La,Y)H_{4}$ was discovered as an impurity phase in synthesized cubic $(La,Y)H_{6}$. The current-voltage measurements show that the critical current density $J_{C}$ in $(La,Y)H_{10}$ may exceed $2500 A/mm^{2}$ at 4.2 K, which is comparable with that for commercial superconducting wires such as ${NbTi}$, $Nb_{3}$${Sn}$. Hydrides that are unstable in a pure form may nevertheless be stabilized at relatively low pressures in solid solutions with superhydrides having the same structure.
