AI 中文总结
本研究结合时间反转方法与特定电子显微镜技术，实现了单个钴纳米颗粒磁涡旋的纳米尺度可视化，揭示了颗粒几何与退磁场的关联，为纳米磁性材料设计提供支撑。
AI 中文摘要
单个纳米颗粒中的磁涡旋是决定下一代磁器件和生物医学应用性能的基础自旋结构。然而，直接成像其完整结构——从循环的面内磁化到纳米尺度的面外核心——仍然具有挑战性。本研究在无磁场环境下，将时间反转方法与倾斜扫描平均差分相位衬度扫描透射电子显微镜相结合，实现了单个钴纳米颗粒中磁涡旋结构的直接定量可视化。该方法可结合原子级分析进行磁成像，并揭示了颗粒几何形状与内部退磁场之间的关联；此外，还追踪了涡旋在原位磁场施加下的动态演化，从而明确确定了面外核心的极性。该方法为关联单个纳米颗粒内的原子级结构与磁性、理解纳米尺度磁性的起源提供了强大平台，为合理设计先进纳米磁性材料和器件提供支持。
英文摘要
Magnetic vortices in individual nanoparticles are fundamental spin structures that govern the properties of next-generation magnetic devices and biomedical applications. However, directly imaging their complete structure, from the circulating in-plane magnetization to the nanometer scale out-of-plane core, remains challenging. Here, direct and quantitative visualization of magnetic vortex structures in individual cobalt nanoparticles is achieved by integrating a time-reversal methodology with tilt-scan-averaged differential phase contrast scanning transmission electron microscopy in a magnetic-field-free environment. This approach enables magnetic imaging in conjunction with atomic-scale analysis and reveals a correlation between particle geometry and internal demagnetizing fields. In addition, dynamic evolution of the vortex under in situ magnetic-field application is tracked, enabling unambiguous determination of the out-of-plane core polarity. This approach provides a powerful platform for correlating atomic-scale structure and magnetism within individual nanoparticles and for understanding the origins of nanoscale magnetic properties, thereby supporting the rational design of advanced nanomagnetic materials and devices.
