Holl Christian, Knol Marvin, Pratzer Marco, Chico Jonathan, Fernandes Imara Lima, Lounis Samir, Morgenstern Markus
II. Institute of Physics B and JARA-FIT, RWTH Aachen University, D-52074, Aachen, Germany.
Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425, Jülich, Germany.
Nat Commun. 2020 Jun 5;11(1):2833. doi: 10.1038/s41467-020-16701-y.
Understanding interactions of magnetic textures with defects is crucial for applications such as racetrack memories or microwave generators. Such interactions appear on the few nanometer scale, where imaging has not yet been achieved with controlled external forces. Here, we establish a method determining such interactions via spin-polarized scanning tunneling microscopy in three-dimensional magnetic fields. We track a magnetic vortex core, pushed by the forces of the in-plane fields, and discover that the core (~ 10 Fe-atoms) gets successively pinned close to single atomic-scale defects. Reproducing the core path along several defects via parameter fit, we deduce the pinning potential as a mexican hat with short-range repulsive and long-range attractive part. The approach to deduce defect induced pinning potentials on the sub-nanometer scale is transferable to other non-collinear spin textures, eventually enabling an atomic scale design of defect configurations for guiding and reliable read-out in race-track type devices.
了解磁织构与缺陷之间的相互作用对于诸如赛道存储器或微波发生器等应用至关重要。此类相互作用出现在几纳米的尺度上，在此尺度下，利用可控外力进行成像尚未实现。在此，我们建立了一种通过三维磁场中的自旋极化扫描隧道显微镜来确定此类相互作用的方法。我们追踪了一个被面内磁场力推动的磁涡旋核，发现该磁核（约10个铁原子）会依次被钉扎在靠近单个原子尺度缺陷的位置。通过参数拟合重现沿多个缺陷的磁核路径，我们推断出钉扎势为具有短程排斥和长程吸引部分的墨西哥帽形状。在亚纳米尺度上推断缺陷诱导钉扎势的方法可转移到其他非共线自旋织构上，最终能够对缺陷构型进行原子尺度设计，以用于赛道型器件中的引导和可靠读出。
