Exchange-field enhancement of superconducting spin pumping
Exchange-field enhancement of superconducting spin pumping
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DOI：
10.1103/physrevb.99.024507
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发表时间：
2019-01-15
影响因子：
3.7
通讯作者：
Blamire, Mark G.
中科院分区：
文献类型：
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作者：
Jeon, Kun-Rok;Ciccarelli, Chiara;Blamire, Mark G.
最近的一项铁磁共振研究[Jeon等人，NA.马特。17,499(2018)]已经报道，当单态超导体(NB)耦合到一个大的自旋轨道耦合(SOC)自旋接收器(如铂)时，单态超导体(NB)的自旋泵浦可以比正常状态大大增强。这种行为可以用Nb/Pt界面上的SOC产生自旋极化的三重态超电流来解释，它与非局部感应磁场共同作用。在这里，我们报告了添加铁磁体(Fe)作为附加交换场的内源到相邻的铂自旋接收器的效果。这大大提高了超导态的自旋泵浦效率，证明了交换场在Nb中产生超导自旋流的关键作用。
A recent ferromagnetic resonance study [Jeon et al., Nat. Mater. 17, 499 (2018)] has reported that spin pumping into a singlet superconductor (Nb) can be greatly enhanced over the normal state when the Nb is coupled to a large spin-orbit-coupling (SOC) spin sink such as Pt. This behavior has been explained in terms of the generation of spin-polarized triplet supercurrents via SOC at the Nb/Pt interface, acting in conjunction with a nonlocally induced magnetic exchange field. Here we report the effect of adding a ferromagnet (Fe) to act as an internal source of an additional exchange field to the adjacent Pt spin sink. This dramatically enhances the spin pumping efficiency in the superconducting state compared with either Pt and Fe separately, demonstrating the critical role of the exchange field in generating superconducting spin currents in the Nb.