Hauptmann Nadine, Haldar Soumyajyoti, Hung Tzu-Chao, Jolie Wouter, Gutzeit Mara, Wegner Daniel, Heinze Stefan, Khajetoorians Alexander A
Institute for Molecules and Materials, Radboud University, 6525 AJ, Nijmegen, Netherlands.
Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Kiel, Germany.
Nat Commun. 2020 Mar 5;11(1):1197. doi: 10.1038/s41467-020-15024-2.
The large interest in chiral magnetic structures for realization of nanoscale magnetic storage or logic devices has necessitated methods which can quantify magnetic interactions at the atomic scale. To overcome the limitations of the typically used current-based sensing of atomic-scale exchange interactions, a force-based detection scheme is highly advantageous. Here, we quantify the atomic-scale exchange force field between a ferromagnetic tip and a cycloidal spin spiral using our developed combination of current and exchange force detection. Compared to the surprisingly weak spin polarization, the exchange force field is more sensitive to atomic-scale variations in the magnetization. First-principles calculations reveal that the measured atomic-scale variations in the exchange force originate from different contributions of direct and indirect (Zener type) exchange mechanisms, depending on the chemical tip termination. Our work opens the perspective of quantifying different exchange mechanisms of chiral magnetic structures with atomic-scale precision using 3D magnetic exchange force field measurements.
对于实现纳米级磁存储或逻辑器件而言，手性磁结构引发了广泛关注，这就需要能够在原子尺度上量化磁相互作用的方法。为克服通常使用的基于电流的原子尺度交换相互作用传感的局限性，基于力的检测方案具有很大优势。在此，我们利用我们开发的电流和交换力检测相结合的方法，量化了铁磁尖端与摆线自旋螺旋之间的原子尺度交换力场。与出人意料的弱自旋极化相比，交换力场对磁化强度的原子尺度变化更为敏感。第一性原理计算表明，所测量的交换力的原子尺度变化源于直接和间接（齐纳型）交换机制的不同贡献，这取决于化学尖端的终止情况。我们的工作开启了利用三维磁交换力场测量以原子尺度精度量化手性磁结构不同交换机制的前景。
