论文标题
热力学方法增强超导临界电流性能
Thermodynamic approach for enhancing superconducting critical current performance
论文作者
论文摘要
人工固定中心的增加导致了超导体中的临界电流密度（$ j _ {\ rm c} $）的令人印象深刻的增加，从而实现了破纪录的所有渗透磁铁和其他应用。 $ j _ {\ rm c} $已达到$ \ sim 0.2 $ - $ 0.3 $ $ $ j _ {\ rm d} $，其中$ j _ {\ rm d} $是电流密度的降低，数值因子取决于固定优化。通过修改$λ$和/或$ξ$，分别是渗透深度和连贯长度，我们可以增加$ j _ {\ rm d} $。对于（y $ _ {0.77} $ gd $ _ {0.23} $）ba $ _2 $ _2 $ _3 $ _3 $ o $ $ _y $（（y，gd）123）我们通过控制载体密度来实现这一目标，这与$λ$和$λ$有关。我们还通过控制基于Fe的超导体的化学压力，BAFE $ _2 $（AS $ _ {1-x} $ p $ _x $）$ _ 2 $胶片来调整$λ$和$ξ$。 $λ$和$ξ$的变化导致$ j _ {\ rm c} $的内在改善，通过$ j _ {\ rm d} $，获得了$ j _ {\ rm c} $ 130 $ ma/cm $ $^$ 8.0 $ ma/cm的$ j _ {\ rm c} $的极高值，$ 130 $ j _ {\ rm d} $的不连贯纳米颗粒掺杂（y，gd）123个涂层导体（ccs）和bafe $ _2 $（as $ _ {1-x x} $ _x $ _x $）$ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2 $ _ 2美元超导体。 （y，gd）123 ccs达到$ \ sim 3.17 $ tn/m $^3 $ $ 4.2 $ k和18 t（$ {\ bf h} \ paratele c $），最高的值报告的最高值。
The addition of artificial pinning centers has led to an impressive increase in critical current density ($J_{\rm c}$) in a superconductor, enabling record-breaking all-superconducting magnets and other applications. $J_{\rm c}$ has reached $\sim 0.2$-$0.3$ $J_{\rm d}$, where $J_{\rm d}$ is the depairing current density, and the numerical factor depends on the pinning optimization. By modifying $λ$ and/or $ξ$, the penetration depth and coherence length, respectively, we can increase $J_{\rm d}$. For (Y$_{0.77}$Gd$_{0.23}$)Ba$_2$Cu$_3$O$_y$ ((Y,Gd)123) we achieve this by controlling the carrier density, which is related to $λ$ and $ξ$. We also tune $λ$ and $ξ$ by controlling the chemical pressure in the Fe-based superconductors, BaFe$_2$(As$_{1-x}$P$_x$)$_2$ films. The variation of $λ$ and $ξ$ leads to an intrinsic improvement of $J_{\rm c}$, via $J_{\rm d}$, obtaining extremely high values of $J_{\rm c}$ of $130$ MA/cm$^2$ and $8.0$ MA/cm$^2$ at $4.2$ K, consistent with an enhancement of $J_{\rm d}$ of a factor of $2$ for both incoherent nanoparticle-doped (Y,Gd)123 coated conductors (CCs) and BaFe$_2$(As$_{1-x}$P$_x$)$_2$ films, showing that this new material design is useful to achieving high critical current densities for a wide array of superconductors. The remarkably high vortex-pinning force in combination with this thermodynamic and pinning optimization route for the (Y,Gd)123 CCs reached $\sim 3.17$ TN/m$^3$ at $4.2$ K and 18 T (${\bf H}\parallel c$), the highest values ever reported in any superconductor.
