Superconductors as spin sources for spintronics
Superconductors as spin sources for spintronics
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DOI：
10.1103/physrevb.77.132501
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发表时间：
2008-04-01
影响因子：
3.7
通讯作者：
Taddei, F.
中科院分区：
文献类型：
--
作者：
Giazotto, F.;Taddei, F.
当超导体的态密度响应交换场 (h(exc)) 发生塞曼分裂时，研究了正常金属-超导体 (NS) 结中的自旋极化输运作为界面透射率和温度的函数。与 Huertas-Hernando 预测的“绝对自旋阀效应”类似 [Phys.莱特牧师。 88, 047003 (2002)]在超导邻近结构中，我们表明 NS 结可用于产生高度自旋极化电流，以替代半金属铁磁体。特别是，通过作用于偏置电压和 h(exc)，所获得的自旋极化电流的大小和符号在很大程度上是可调的。对于隧道接触，电流极化可以高达 100%，而对于透明结，它主要由少数自旋物种主导。超导间隙提供的电子“冷却”可以增强该效果。
Spin-polarized transport is investigated in normal metal-superconductor (NS) junctions as a function of interface transmissivity as well as temperature when the density of states of a superconductor is Zeeman-split in response to an exchange field (h(exc)). Similarly to the "absolute spin-valve effect" predicted by Huertas-Hernando [Phys. Rev. Lett. 88, 047003 (2002)] in superconducting proximity structures, we show that NS junctions can be used to generate highly spin-polarized currents, in alternative to half-metallic ferromagnets. In particular, the spin-polarized current obtained is largely tunable in magnitude and sign by acting on bias voltage and h(exc). While for tunnel contacts the current polarization can be as high as 100%, for transparent junctions it is dominated by the minority spin species. The effect can be enhanced by electron "cooling" provided by the superconducting gap.