Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 127-72, Pasadena, California 91125, USA.
Nano Lett. 2010 Oct 13;10(10):4206-10. doi: 10.1021/nl102584j.
We show the theoretical depairing current limit can be achieved in a robust fashion in highly ordered superconductor nanomesh films having spatial periodicities smaller than both the superconducting coherence length and the magnetic penetration depth. For a niobium nanomesh film with 34 nm spatial periodicity, the experimental critical current density is enhanced by more than 17 times over the continuous film and is in good agreement with the depairing limit over the entire measured temperature range. The nanomesh superconductors are also less susceptible to thermal fluctuations when compared to nanowire superconductors. T(c) values similar to the bulk film are achieved, and the nanomeshes are capable of retaining superconductivity to higher fields relative to the bulk. In addition, periodic oscillations in T(c) are observed as a function of field, reflecting the highly ordered nanomesh structure.
我们展示了理论上的退极化电流限制可以在高度有序的超导纳米网薄膜中以稳健的方式实现，这些薄膜的空间周期性小于超导相干长度和磁穿透深度。对于具有 34nm 空间周期性的铌纳米网薄膜，实验临界电流密度比连续薄膜提高了 17 倍以上，并且在整个测量温度范围内与退极化限制很好地吻合。与纳米线超导体相比，纳米网超导体受热波动的影响也较小。实现了与块体薄膜相似的 Tc 值，并且纳米网相对于块体能够保持更高的超导性。此外，作为磁场的函数，观察到 Tc 的周期性振荡，反映了高度有序的纳米网结构。
