Meyer Sebastian, Perini Marco, von Malottki Stephan, Kubetzka André, Wiesendanger Roland, von Bergmann Kirsten, Heinze Stefan
Institute of Theoretical Physics and Astrophysics, Christian-Albrechts-Universität zu Kiel, Leibnizstrasse 15, 24098, Kiel, Germany.
Department of Physics, University of Hamburg, Jungiusstrasse 11, 20355, Hamburg, Germany.
Nat Commun. 2019 Aug 23;10(1):3823. doi: 10.1038/s41467-019-11831-4.
Due to their exceptional topological and dynamical properties magnetic skyrmions-localized stable spin structures-show great promise for spintronic applications. To become technologically competitive, isolated skyrmions with diameters below 10 nm stable at zero magnetic field and at room temperature are desired. Despite finding skyrmions in a wide spectrum of materials, the quest for a material with these envisioned properties is ongoing. Here we report zero field isolated skyrmions at T = 4 K with diameters below 5 nm observed in the virgin ferromagnetic state coexisting with 1 nm thin domain walls in Rh/Co atomic bilayers on Ir(111). These spin structures are investigated by spin-polarized scanning tunneling microscopy and can also be detected using non-spin-polarized tips via the noncollinear magnetoresistance. We demonstrate that sub-10 nm skyrmions are stabilized in these ferromagnetic Co films at zero field due to strong frustration of exchange interaction, together with Dzyaloshinskii-Moriya interaction and large magnetocrystalline anisotropy.
由于其独特的拓扑和动力学特性，磁性斯格明子（局部稳定的自旋结构）在自旋电子学应用中显示出巨大潜力。为了在技术上具有竞争力，需要直径小于10纳米的孤立斯格明子在零磁场和室温下保持稳定。尽管在多种材料中都发现了斯格明子，但寻找具有这些预期特性的材料的工作仍在进行。在此，我们报告在Ir(111)上的Rh/Co原子双层中，在原始铁磁态下观察到直径小于5纳米的零场孤立斯格明子，其与1纳米厚的畴壁共存于T = 4 K时。这些自旋结构通过自旋极化扫描隧道显微镜进行研究，也可以使用非自旋极化尖端通过非共线磁电阻进行检测。我们证明，由于交换相互作用的强烈受挫，以及Dzyaloshinskii-Moriya相互作用和大的磁晶各向异性，亚10纳米的斯格明子在零场下在这些铁磁Co薄膜中得以稳定。
