Karabassov Tairzhan, Guravova Anastasia V, Kuzin Aleksei Yu, Kazakova Elena A, Kawabata Shiro, Lvov Boris G, Vasenko Andrey S
National Research University Higher School of Economics, 101000 Moscow, Russia.
Skolkovo Institute of Science and Technology, 121205 Moscow, Russia.
Beilstein J Nanotechnol. 2020 Jan 23;11:252-262. doi: 10.3762/bjnano.11.19. eCollection 2020.
We present a quantitative study of the current-voltage characteristics (CVC) of SFIFS Josephson junctions (S = bulk superconductor, F = metallic ferromagnet, I = insulating barrier) with weak ferromagnetic interlayers in the diffusive limit. The problem is solved in the framework of the nonlinear Usadel equations. We consider the case of a strong tunnel barrier such that the left SF and the right FS bilayers are decoupled. We calculate the density of states (DOS) in SF bilayers using a self-consistent numerical method. Then we obtain the CVC of corresponding SFIFS junctions, and discuss their properties for different set of parameters including the thicknesses of ferromagnetic layers, the exchange field, and the magnetic scattering time. We observe an anomalous nonmonotonic CVC in case of weak ferromagnetic interlayers, which we attribute to DOS energy dependencies in the case of small exchange fields in the F layers.
我们对处于扩散极限且具有弱铁磁中间层的SFIFS约瑟夫森结（S = 体超导体，F = 金属铁磁体，I = 绝缘势垒）的电流 - 电压特性（CVC）进行了定量研究。该问题在非线性乌萨德尔方程的框架内得到解决。我们考虑强隧道势垒的情况，使得左侧的SF和右侧的FS双层解耦。我们使用自洽数值方法计算SF双层中的态密度（DOS）。然后我们得到相应SFIFS结的CVC，并讨论它们在不同参数集下的特性，包括铁磁层的厚度、交换场和磁散射时间。在弱铁磁中间层的情况下，我们观察到异常的非单调CVC，我们将其归因于F层中交换场较小时DOS与能量的依赖关系。
