论文标题
具有纳米尺度分辨率的磁感应场的高敏性映射：离轴电子全息和像素化差异相对比的比较
High-sensitivity mapping of magnetic induction fields with nanometer-scale resolution: comparison of off-axis electron holography and pixelated differential phase contrast
论文作者
论文摘要
我们比较了两种基于透射电子显微镜（TEM）技术，这些技术可以在高灵敏度下对磁感应场进行高度分辨的定量测量。为此，已经测量并将其与微磁建模进行了测量，并将其与微磁性建模进行了比较。已经使用大量全息图的平均进行了最先进的电子全息图，以提高测量值的敏感性。然后比较这些结果从像素化（或4D）扫描透射电子显微镜（STEM）获得的结果。这种新兴技术使用像素化检测器来对局部衍射模式进行成像，因为在样品上扫描了光束。对于每个衍射图，测量梁的挠度并将其转换为磁感应，而扫描梁则可以构建图。 TEM和Stem的畸变校正后的Lorentz（无现场）构型用于改进的空间分辨率。我们表明，即使使用旧产生的电荷耦合器件摄像机执行的像素化STEM方法，也以空间分辨率为代价提供了更好的灵敏度。给出了两种技术的更一般比较。
We compare two transmission electron microscopy (TEM) based techniques that can provide highly spatially resolved quantitative measurements of magnetic induction fields at high sensitivity. To this end, the magnetic induction of a ferromagnetic NiFe nanowire has been measured and compared to micromagnetic modelling. State-of-the-art electron holography has been performed using the averaging of large series of holograms to improve the sensitivity of the measurements. These results are then compared those obtained from pixelated (or 4D) scanning transmission electron microscopy (STEM). This emerging technique uses a pixelated detector to image the local diffraction patterns as the beam is scanned over the sample. For each diffraction pattern, the deflection of the beam is measured and converted into magnetic induction, while scanning the beam allows to build a map. Aberration corrected Lorentz (field-free) configurations of the TEM and STEM were used for an improved spatial resolution. We show that the pixelated STEM approach, even when performed using an old generation of charge-coupled device camera, provides better sensitivity at the expense of spatial resolution. A more general comparison of the two techniques is given.
