Fermin Remko, van Dinter Dyon, Hubert Michel, Woltjes Bart, Silaev Mikhail, Aarts Jan, Lahabi Kaveh
Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
Department of Physics and Nanoscience Center, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
Nano Lett. 2022 Mar 23;22(6):2209-2216. doi: 10.1021/acs.nanolett.1c04051. Epub 2022 Mar 3.
Since the discovery of the long-range superconducting proximity effect, the interaction between spin-triplet Cooper pairs and magnetic structures such as domain walls and vortices has been the subject of intense theoretical discussions, while the relevant experiments remain scarce. We have developed nanostructured Josephson junctions with highly controllable spin texture, based on a disk-shaped Nb/Co bilayer. Here, the vortex magnetization of Co and the Cooper pairs of Nb conspire to induce long-range triplet (LRT) superconductivity in the ferromagnet. Surprisingly, the LRT correlations emerge in highly localized (sub-80 nm) channels at the rim of the ferromagnet, despite its trivial band structure. We show that these robust rim currents arise from the magnetization texture acting as an effective spin-orbit coupling, which results in spin accumulation at the bilayer-vacuum boundary. Lastly, we demonstrate that by altering the spin texture of a single ferromagnet, both 0 and π channels can be realized in the same device.
自从发现长程超导邻近效应以来，自旋三重态库珀对与诸如畴壁和涡旋等磁结构之间的相互作用一直是激烈理论讨论的主题，而相关实验仍然很少。我们基于盘状铌/钴双层结构开发了具有高度可控自旋纹理的纳米结构约瑟夫森结。在这里，钴的涡旋磁化和铌的库珀对共同作用，在铁磁体中诱导出长程三重态（LRT）超导性。令人惊讶的是，尽管铁磁体的能带结构平凡，但LRT相关性却出现在铁磁体边缘高度局域化（小于80纳米）的通道中。我们表明，这些稳健的边缘电流源于作为有效自旋 - 轨道耦合的磁化纹理，这导致在双层 - 真空边界处的自旋积累。最后，我们证明通过改变单个铁磁体的自旋纹理，可以在同一器件中实现0和π通道。
