AI 中文总结
研究Ta/CoFeB/MgO单层厚膜中斯格明子的拓扑霍尔效应，利用磁光克尔显微镜成像表面磁化以分离该效应，测量出室温下的拓扑霍尔电阻率，通过与热输运和电输运测量对比验证结果，实现对拓扑和反常霍尔贡献的分离。
AI 中文摘要
拓扑霍尔效应是指示拓扑保护磁结构存在的重要工具。本文展示了对Ta/CoFeB/MgO单层厚膜中拓扑保护斯格明子的拓扑霍尔效应测量。该材料体系中拓扑霍尔效应小且反常霍尔效应占主导，给直接检测带来挑战。利用磁光克尔显微镜成像表面磁化，分离拓扑霍尔效应。测量揭示室温下Ta/CoFeB/MgO层堆叠的拓扑霍尔电阻率为249(18) \si{\pico\ohm\meter}。磁光克尔效应测量还能追踪斯格明子形成。通过与热输运和电输运测量结果对比验证了结果。
英文摘要
The topological Hall effect is a valuable tool to indicate the presence of topologically protected magnetic structures. In this work, we present topological Hall effect measurements originating from topologically protected skyrmions in Ta/CoFeB/MgO single-layer thick films with a one nanometer thick magnetic layer. The simultaneous occurrence of the small topological Hall effect and the dominating anomalous Hall effect in this material system makes direct detection challenging as compared to bulk or multilayer systems. In electronic transport measurements, both effects' contributions impact electron trajectories in the same way, overlapping in the measurement signal, and require disentanglement. Magneto-optical Kerr microscopy was used to image the surface magnetization, enabling the separation of the topological Hall effect from other Hall effect contributions. These measurements reveal a topological Hall resistivity of $249(18)\,$\si{\pico\ohm\meter} for Ta/CoFeB/MgO layer stacks at room temperature. Magneto-optical Kerr effect (MOKE) measurements also allow tracking skyrmion formation during external magnetic field sweeps to confirm their occurrence when measuring the topological Hall effect. We verify this outcome by comparing the results with thermal and electrical transport measurements from which we calculate the overall topological quantity that gives rise to the topological Nernst and Hall effect, respectively.
Comments26 pages, 8 figures
