论文标题
局部不均匀磁场中的约瑟夫森连接
Josephson junctions in a local inhomogeneous magnetic field
论文作者
论文摘要
在各种实验情况下，约瑟夫森连接可以遭受局部，强烈的不均匀磁场。在这里，该问题在分析和数值上进行分析。在静态和动态情况下，在存在时间依赖的局部场的情况下，在存在时间依赖的局部场的情况下进行了修改的正弦 - 戈登类型方程。考虑了两个特定的局部场示例：由Abrikosov涡流或磁力显微镜（MFM）诱导。证明时间依赖的局部场可以通过穿梭或单向棘轮状的约瑟夫森涡流运动在交界处诱导动态通量流状态。这提供了通过振荡MFM尖端检测和操纵约瑟夫森涡流的机制。在静态情况下，本地场导致关键电流与磁场的变形，$ i_c（h）$，调制模式。失真对局部场的形状和幅度都敏感。因此，$ i_c（h）$模式包含有关路口内本地现场分布的信息。这打开了使用单个Josephson连接作为一种扫描探针传感器的可能性，其空间分辨率不受其几何大小的限制，从而避免了已知的问题，即传感器的场灵敏度和空间分辨率之间的权衡问题。
A Josephson junction can be subjected to a local, strongly inhomogeneous magnetic field in various experimental situations. Here this problem is analyzed analytically and numerically. A modified sine-Gordon type equation in the presence of time-dependent local field is derived and solved numerically in static and dynamic cases. Two specific examples of local fields are considered: induced either by an Abrikosov vortex, or by a tip of a magnetic force microscope (MFM). It is demonstrated that time-dependent local field can induce a dynamic flux-flow state in the junction with shuttling, or unidirectional ratchet-like Josephson vortex motion. This provides a mechanism of detection and manipulation of Josephson vortices by an oscillating MFM tip. In a static case local field leads to a distortion of the critical current versus magnetic field, $I_c(H)$, modulation pattern. The distortion is sensitive to both the shape and the amplitude of the local field. Therefore, the $I_c(H)$ pattern carries information about the local field distribution within the junction. This opens a possibility for employing a single Josephson junction as a scanning probe sensor with spatial resolution not limited by its geometrical size, thus obviating a known problem of a trade-off between field sensitivity and spatial resolution of a sensor.
