论文标题
nb $ _5 $ ir $ _ {3-x} $ pt $ _x $ o合金中的多重到单间隙超导性交叉
Multiple- to single-gap superconductivity crossover in Nb$_5$Ir$_{3-x}$Pt$_x$O alloys
论文作者
论文摘要
通过主要使用Muon-Spin旋转/放松（$μ$ SR）技术，我们研究了NB $ _5 $ _5 $ ir $ _ {3-x} $ pt $ _x $ o（$ x = 0 $ x = 0 $和1.6）的超导率（SC），分别具有$ t_c = 10.5 $ k和9.1 k和9.1 k。在宏观水平上，通过电阻率，磁化和特定热测量来研究它们的超导性。在这两种化合物中，电子特异性热和低温超流体密度数据表明无节性sc。 $ t_c $时的超导差距值和特定的热量不连续性大于弱耦合体制中的Bardeen-Cooper-Schrieffer理论的预期，表明NB $ _5 $ _5 $ _5 $ _ {3-X} $ pt $ _x $ _x $ _x $ _x $ o _x $ o o o o _x $ _x $ o _x $ o o o。在NB $ _5 $ ir $ _3 $ o中，Multigap SC可以通过电子特异性热系数和超导导向的高斯放松率以及上部临界场的温度依赖性来证明。 PT替换抑制了其中一个空白，而NB $ _5 $ ir $ _ {1.4} $ pt $ _ {1.6} $ o成为单间隙超导体。通过结合我们广泛的实验结果，我们为NB $ _5 $ ir $ _ {3-x} $ pt $ _x $ o family提供了多个和单间SC跨界的证据。
By using mostly the muon-spin rotation/relaxation ($μ$SR) technique, we investigate the superconductivity (SC) of Nb$_5$Ir$_{3-x}$Pt$_x$O ($x = 0$ and 1.6) alloys, with $T_c = 10.5$ K and 9.1 K, respectively. At a macroscopic level, their superconductivity was studied by electrical resistivity, magnetization, and specific-heat measurements. In both compounds, the electronic specific heat and the low-temperature superfluid density data suggest a nodeless SC. The superconducting gap value and the specific heat discontinuity at $T_c$ are larger than that expected from the Bardeen-Cooper-Schrieffer theory in the weak-coupling regime, indicating strong-coupling superconductivity in the Nb$_5$Ir$_{3-x}$Pt$_x$O family. In Nb$_5$Ir$_3$O, multigap SC is evidenced by the field dependence of the electronic specific heat coefficient and the superconducting Gaussian relaxation rate, as well as by the temperature dependence of the upper critical field. Pt substitution suppresses one of the gaps, and Nb$_5$Ir$_{1.4}$Pt$_{1.6}$O becomes a single-gap superconductor. By combining our extensive experimental results, we provide evidence for a multiple- to single-gap SC crossover in the Nb$_5$Ir$_{3-x}$Pt$_x$O family.
