Controlled suppression of superconductivity by the generation of polarized Cooper pairs in spin-valve structures
Controlled suppression of superconductivity by the generation of polarized Cooper pairs in spin-valve structures
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DOI：
10.1103/physrevb.91.060501
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发表时间：
2015-02-02
影响因子：
3.7
通讯作者：
Lee, S. L.
中科院分区：
文献类型：
--
作者：
Flokstra, M. G.;Cunningham, T. C.;Lee, S. L.
给出了薄膜超导自旋阀系统的输运测量结果，其中两个铁磁性Co层的受控非共线排列可以用来影响Nb的超导状态。我们观察到超导转变温度随两层铁磁层的相对取向有非常明显的振荡。我们的测量使我们能够区分磁区平均、杂散偶极场和超导自旋三重态形成的竞争影响。对于反平行位形的交换场，磁区平均化导致相变温度的微弱提高，而对于其他位形，则有较大的变化，这可以归因于自旋三重态形成的引出电流。
Transport measurements are presented on thin-film superconducting spin-valve systems, where the controlled noncollinear arrangement of two ferromagnetic Co layers can be used to influence the superconducting state of Nb. We observe a very clear oscillation of the superconducting transition temperature with the relative orientation of the two ferromagnetic layers. Our measurements allow us to distinguish between the competing influences of domain averaging, stray dipolar fields, and the formation of superconducting spin triplets. Domain averaging is shown to lead to a weak enhancement of transition temperature for the antiparallel configuration of exchange fields, while much larger changes are observed for other configurations, which can be attributed to drainage currents due to spin triplet formation.