Ali Hasan, Rusz Jan, Bürgler Daniel E, Vas Joseph V, Jin Lei, Adam Roman, Schneider Claus M, Dunin-Borkowski Rafal E
Department of Materials Science and Engineering, Uppsala University, Uppsala, Sweden.
Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, Jülich, Germany.
Nat Mater. 2025 May 12. doi: 10.1038/s41563-025-02242-6.
Magnetism originates from the spin and orbital angular momenta of electrons and their coupling. These interactions occur at subatomic scales and a comprehensive understanding of such phenomena relies on characterization techniques capable of probing the spin and orbital moments at atomic resolution. Although electron energy loss magnetic chiral dichroism has previously enabled the detection of magnetic moments at atomic scales, it was limited to a chromatic-aberration-corrected transmission electron microscope. Although possible, the detection of atomic-scale electron energy loss magnetic chiral dichroism in a scanning transmission electron microscope remains elusive due to challenges associated with convergent beam setups. Here we demonstrate the detection of atomic-scale electron energy loss magnetic chiral dichroism signals in a probe-corrected scanning transmission electron microscope. We not only determine the orbital-to-spin moments ratio for individual atomic planes of an iron crystal but also reveal its local variations at subatomic scales. These findings open the possibility of resolving magnetism down to the orbital level in future studies.
磁性起源于电子的自旋和轨道角动量及其耦合。这些相互作用发生在亚原子尺度上，而对这类现象的全面理解依赖于能够在原子分辨率下探测自旋和轨道磁矩的表征技术。尽管电子能量损失磁圆二色性此前已能够在原子尺度上检测磁矩，但它仅限于色差校正透射电子显微镜。虽然在扫描透射电子显微镜中检测原子尺度的电子能量损失磁圆二色性是可能的，但由于与会聚束设置相关的挑战，其检测仍然难以实现。在此，我们展示了在探针校正扫描透射电子显微镜中检测原子尺度的电子能量损失磁圆二色性信号。我们不仅确定了铁晶体单个原子平面的轨道磁矩与自旋磁矩之比，还揭示了其在亚原子尺度上的局部变化。这些发现为未来研究中将磁性解析到轨道水平开辟了可能性。
