arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1908.08460cond-mat.supr-con
收藏

磁约瑟夫森结中库珀对的相位相关自旋极化

Phase-dependent Spin Polarization of Cooper Pairs in Magnetic Josephson Junctions

Samme M. Dahir, Anatoly F. Volkov, Ilya M. Eremin

摘要:

在过去的几十年里,超导体-铁磁体混合结构(SF)引起了人们极大的兴趣,这是由于在这些结构中预测和观察到的各种有趣的现象。其中之一就是所谓的逆邻近效应。它由库珀对的自旋极化来描述,这种极化不仅发生在铁磁体(F)中,而且发生在超导体(S)中,从而在超导体内部产生有限的磁矩$M_{\text{S}}$。这种效应已被预测和实验研究。然而,对实验数据的解释大多是模糊的。本文从理论上研究了自旋极化库珀对对SFS结中约瑟夫森效应的影响。我们表明,感应磁矩$M_{\text{S}}$不依赖于相位差$φ$,因此,将振荡的约瑟夫森频率$2eV/\hbar$的时间,如果电流超过一个临界值。最重要的是,超导体中的自旋极化导致夫琅和费图案的显着变化,这可以很容易地通过实验获得。

英文摘要:

Superconductor-Ferromagnet hybrid structures (SF) have attracted much interest in the last decades, due to a variety of interesting phenomena predicted and observed in these structures. One of them is the so-called inverse proximity effect. It is described by a spin polarization of Cooper pairs, which occurs not only in the ferromagnet (F), but also in the superconductor (S) yielding a finite magnetic moment $M_{\text{S}}$ inside the superconductor. This effect has been predicted and experimentally studied. However, interpretation of the experimental data is mostly ambiguous. Here, we study theoretically the impact of the spin polarized Cooper pairs on the Josephson effect in an SFS junction. We show that the induced magnetic moment $M_{\text{S}}$ does depend on the phase difference $φ$ and therefore, will oscillate in time with the Josephson frequency $2eV/\hbar$ if the current exceeds a critical value. Most importantly, the spin polarization in the superconductor causes a significant change in the Fraunhofer pattern, which can be easily accessed experimentally.

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。

↑