Long-ranged triplet supercurrent in a single in-plane ferromagnet with spin-orbit coupled contacts to superconductors
Long-ranged triplet supercurrent in a single in-plane ferromagnet with spin-orbit coupled contacts to superconductors
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DOI：
10.1103/physrevb.100.224519
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发表时间：
2019-12-27
影响因子：
3.7
通讯作者：
Linder, Jacob
中科院分区：
文献类型：
--
作者：
Eskilt, Johannes R.;Amundsen, Morten;Linder, Jacob
通过将传统的自旋单线态库珀对转化为极化的自旋三重态对，可以在强铁磁体中维持长距离的自旋极化超电流。通过自旋轨道相互作用获得这种转换，而不是磁不均匀性，最近已经在文献中进行了探索。关于实验检测的一个具有挑战性的方面是，为了使Rashba自旋轨道相互作用（例如，由于反转对称性破缺而出现在界面上）产生如此长距离的超电流，需要磁化的面外分量。这限制了材料的选择，并可能在超导区域引起涡流，使测量结果的解释复杂化。因此，我们希望找到一种方法，使Rashba自旋-轨道相互作用能够诱导纯平面内磁化旋转的远程超电流。在这里，我们展示了这在一个横向约瑟夫森结中是可能的，在这个结中，两个超导电极通过两个薄的、重的普通金属与铁磁膜接触。当只使用单一磁层时，这种设置中的超电流的大小可以通过平面内磁化角来调节。这些结果可以提供一种新的和更简单的方法来产生可控的自旋极化超电流，而不是利用复杂的磁织构Josephson结。
By converting conventional spin-singlet Cooper pairs to polarized spin-triplet pairs, it is possible to sustain long-ranged spin-polarized supercurrents flowing through strong ferromagnets. Obtaining such a conversion via spin-orbit interactions, rather than magnetic inhomogeneities, has recently been explored in the literature. A challenging aspect with regard to experimental detection has been that in order for Rashba spin-orbit interactions, present, e.g., at interfaces due to inversion symmetry breaking, to generate such long-ranged supercurrents, an out-of-plane component of the magnetization is required. This limits the choice of materials and can induce vortices in the superconducting region complicating the interpretation of measurements. Therefore, it would be desirable to identify a way in which Rashba spin-orbit interactions can induce long-ranged supercurrents for purely in-plane rotations of the magnetization. Here, we show that this is possible in a lateral Josephson junction where two superconducting electrodes are placed in contact with a ferromagnetic film via two thin, heavy normal metals. The magnitude of the supercurrent in such a setup becomes tunable by the in-plane magnetization angle when using only a single magnetic layer. These results could provide a new and simpler way to generate controllable spin-polarized supercurrents than previous experiments which utilized complicated magnetically textured Josephson junctions.