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arXiv 1604.07155cond-mat.supr-con
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弱连接超导体-铁磁体约瑟夫森结构理论

Theory of a Weak-Link Superconductor-Ferromagnet Josephson Structure

Jan Gelhausen, Matthias Eschrig

摘要:

我们提出了一个弱连接约瑟夫森结的理论描述模型,其中弱连接由于靠近铁磁金属(S-(F))而自旋极化|S)-S)。采用Usadel输运理论适用于扩散系统,我们表明,薄弱环节的Andreev电路理论的框架内描述的自旋相关的边界条件的实施所产生的有效自能。这导致了相当大的简化模型,并允许一个有效的数值处理。作为我们模型的一个应用,我们给出了一些重要的物理观测值的数值计算,如局域态密度,邻近诱导的小间隙,自旋磁化,以及约瑟夫森电流的相位和温度依赖性的S-(F| S)-S系统。我们讨论了多值的电流相位关系在低温下,以及他们的交叉在高温下的正弦形式。此外,我们数值处理(S-F-S)系统,表现出一个磁畴壁的F区和计算的临界电流的温度依赖性。

英文摘要:

We propose a model for the theoretical description of a weak-link Josephson junction, in which the weak link is spin-polarized due to proximity to a ferromagnetic metal (S-(F|S)-S). Employing Usadel transport theory appropriate for diffusive systems, we show that the weak link is described within the framework of Andreev circuit theory by an effective self-energy resulting from the implementation of spin-dependent boundary conditions. This leads to a considerable simplification of the model, and allows for an efficient numerical treatment. As an application of our model, we show numerical calculations of important physical observables such as the local density of states, proximity-induced minigaps, spin-magnetization, and the phase and temperature-dependence of Josephson currents of the S-(F|S)-S system. We discuss multi-valued current-phase relationships at low temperatures as well as their crossover to sinusoidal form at high temperatures. Additionally, we numerically treat (S-F-S) systems that exhibit a magnetic domain wall in the F region and calculate the temperature- dependence of the critical currents.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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