Observation of vortex dynamics in two-dimensional Josephson-junction arrays.
Observation of vortex dynamics in two-dimensional Josephson-junction arrays.
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二维约瑟夫森结阵列中涡动力学的观察。
DOI：
10.1103/physrevb.50.3158
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Benz
中科院分区：
文献类型：
--
作者：
Lachenmann;Doderer;Hoffmann;Huebener;Booi;Benz
利用低温扫描电子显微镜获得了Nb/${\ mathit{AlO}}_{\mathit{x}}$/Nb Josephson结电流偏置二维阵列的动态状态的空间分辨图像。阵列为正方形或矩形，最大尺寸为20个结点\ifmmode\times\else\texttimes\fi{}20个结点。在过阻尼阵列中，我们在零或小的垂直磁场下的图像与模型计算一起证实了一个样品边缘的漩涡（或相反边缘的反漩涡）的成核及其随后进入阵列内部的运动。由于涡旋-反涡旋碰撞导致的涡旋湮灭发生在阵列的中间或与成核边缘相反的边缘。这些动力学和潜在的模型考虑与薄膜ii型超导体电流诱导电阻状态下的阿布里科索夫涡流相似。在欠阻尼阵列的图像中直接证实了“行切换”现象。当多次建立电流-电压特性上的相同偏置点时，经历此过程的特定行随机变化，每次从零电流开始。
Spatially resolved images of the dynamic states of curent-biased two-dimensional arrays of Nb/${\mathrm{AlO}}_{\mathit{x}}$/Nb Josephson junctions were obtained using low-temperature scanning electron microscopy. The arrays were square or rectangular and the maximum size was 20 junctions \ifmmode\times\else\texttimes\fi{}20 junctions. In overdamped arrays our images at zero or small applied perpendicular magnetic field together with model calculations confirm the nucleation of a vortex at one sample edge (or an antivortex at the opposite edge) and its subsequent motion into the array interior. Vortex annihilation due to vortex-antivortex collision was observed to take place in the middle of the array or at the edge opposite to the nucleation edge. These dynamics and the underlying model considerations are similar to that for Abrikosov vortices in the current-induced resistive state of thin film type-II superconductors. The phenomenon of ``row switching'' is directly confirmed in images of underdamped arrays. The specific rows experiencing this process change randomly when the same bias point on the current-voltage characteristic is established many times, starting each time from zero current.