Untersuchung von Semifluxonen in langen Josephson 0-pi-Kontakten

由于最近制备技术的进步，现在有几种类型的p结可用于实验研究，例如基于具有d波序参数对称性的各向异性铜酸盐超导体或基于超导体-铁磁结构。在包含长度与约瑟夫森穿透深度Lj相当的0和p部分的长约瑟夫森结中，在0和p小面连接的点上，在一定条件下自发地产生分数涡。这种分数旋涡通常只携带一半的磁通量，因此被称为半流子。在这个项目中，我们专注于对0-p-LJJ中分数涡行为的实验研究。半流子和流子非常不同，它们形成基态的方式，它们如何运动，它们如何相互作用，以及它们与流子的相互作用。半流子可以导致可观测参数的半整数量子化，并具有许多其他有趣的特征。这项研究旨在加深对超导体中分数量子化的理解，研究分数磁通量子的行为，并为经典或量子区域的约瑟夫森电子学提出和尝试新的想法。

Due to the recent progress in fabrication technology, several types of p-junctions, e.g. based on anisotropic cuprate superconductors with d-wave order parameter symmetry or on superconductor-ferromagnet structures, are available now for experimental investigations. In a long Josephson junction containing 0 and p parts comparable by length with the Josephson penetration depth lJ, at the point where 0 and p facets join, fractional vortices are spontaneously created at certain conditions. Such fractional vortices usually carry only one half of a magnetic flux quantum and therefore are called semifluxons. Within this project we focus on the experimental investigation of the behaviour of fractional vortices in 0-p-LJJs. Semifluxons are very different from fluxons in a way they form a ground state, how they move, how they interact with each other and with fluxons. Semifluxons can result in half-integer quantization of observable parameters and have many other interesting features. This investigation is intended to improve the understanding of fractional quantization in superconductors, to study the behavior of fractional flux quanta and to suggest and try new ideas for Josephson electronics in the classical or the quantum regime.