Periodic Co/Nb pseudo spin valve for cryogenic memory
Periodic Co/Nb pseudo spin valve for cryogenic memory
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DOI：
10.3762/bjnano.10.83
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发表时间：
2019-04-09
影响因子：
3.1
通讯作者：
Keimer, Bernhard
中科院分区：
文献类型：
--
作者：
Klenov, Nikolay;Khaydukov, Yury;Keimer, Bernhard
我们提出了一个可控的有效交换能的约瑟夫森开关和存储器应用的磁性结构的研究。作为弱连接的基础，我们建议使用由薄超导体间隔的铁磁（F）层组成的周期性结构。基于Usadel方程的计算表明，相邻F层从平行（P）到反平行（AP）排列的切换可以导致通过结的临界电流的显著增强。为了控制磁取向，我们建议使用一个周期性系统，其晶胞是结构为F-1/s/F-2/s的伪自旋阀，其中F-1和F-2是具有不同矫顽场的两个磁性层。为了检验通过整个周期结构在AP和P态之间可控切换的可行性，我们在两个Nb（25 nm）超导层之间制备了超晶格[Co（1.5 nm）/Nb（8 nm）/Co（2.5 nm）/Nb（8 nm）]（6）。中子散射和磁力测量数据表明，平行和反平行排列可以控制只有几十奥斯特的磁场。
We present a study of magnetic structures with controllable effective exchange energy for Josephson switches and memory applications. As a basis for a weak link we propose to use a periodic structure composed of ferromagnetic (F) layers spaced by thin superconductors (s). Our calculations based on the Usadel equations show that switching from parallel (P) to antiparallel (AP) alignment of neighboring F layers can lead to a significant enhancement of the critical current through the junction. To control the magnetic alignment we propose to use a periodic system whose unit cell is a pseudo spin valve of structure F-1/s/F-2/s where F-1 and F-2 are two magnetic layers having different coercive fields. In order to check the feasibility of controllable switching between AP and P states through the whole periodic structure, we prepared a superlattice [Co(1.5 nm)/Nb(8 nm)/Co(2.5 nm)/Nb(8 nm)](6) between two superconducting layers of Nb(25 nm). Neutron scattering and magnetometry data showed that parallel and antiparallel alignment can be controlled with a magnetic field of only several tens of Oersted.