Institute for Molecules and Materials, Radboud University , 6525 AJ Nijmegen, Netherlands.
Nano Lett. 2017 Sep 13;17(9):5660-5665. doi: 10.1021/acs.nanolett.7b02538. Epub 2017 Aug 14.
Storing and accessing information in atomic-scale magnets requires magnetic imaging techniques with single-atom resolution. Here, we show simultaneous detection of the spin-polarization and exchange force with or without the flow of current with a new method, which combines scanning tunneling microscopy and noncontact atomic force microscopy. To demonstrate the application of this new method, we characterize the prototypical nanoskyrmion lattice formed on a monolayer of Fe/Ir(111). We resolve the square magnetic lattice by employing magnetic exchange force microscopy, demonstrating its applicability to noncollinear magnetic structures for the first time. Utilizing distance-dependent force and current spectroscopy, we quantify the exchange forces in comparison to the spin-polarization. For strongly spin-polarized tips, we distinguish different signs of the exchange force that we suggest arises from a change in exchange mechanisms between the probe and a skyrmion. This new approach may enable both nonperturbative readout combined with writing by current-driven reversal of atomic-scale magnets.
在原子级磁铁中存储和访问信息需要具有单原子分辨率的磁成像技术。在这里，我们展示了一种新方法，该方法结合扫描隧道显微镜和非接触原子力显微镜，同时检测电流有无流动时的自旋极化和交换力。为了展示这种新方法的应用，我们对单层 Fe/Ir(111)上形成的原型纳米斯格明子晶格进行了表征。我们通过采用磁交换力显微镜解析了正方形磁晶格，首次证明了其在非共线磁结构中的适用性。利用距离相关的力和电流谱，我们定量比较了自旋极化和交换力。对于强自旋极化的探针，我们区分了不同符号的交换力，我们建议这种交换力源于探针和斯格明子之间的交换机制的变化。这种新方法可能使非微扰读出与通过电流驱动的原子级磁铁反转进行写入相结合成为可能。
