Magnetic skyrmions are promising candidates for future storage devices with a large data density. A great variety of materials have been found that host skyrmions up to the room-temperature regime. Lorentz microscopy, usually performed in a transmission electron microscope (TEM), is one of the most important tools for characterizing skyrmion samples in real space. Using numerical calculations, this work relates the phase contrast in a TEM to the actual magnetization profile of an isolated Néel or Bloch skyrmion, the two most common skyrmion types. Within the framework of the used skyrmion model, the results are independent of skyrmion size and wall width and scale with sample thickness for purely magnetic specimens. Simple rules are provided to extract the actual skyrmion configuration of pure Bloch or Néel skyrmions without the need of simulations. Furthermore, first differential phase contrast (DPC) measurements on Néel skyrmions that meet experimental expectations are presented and showcase the described principles. The work is relevant for material sciences where it enables the engineering of skyrmion profiles via convenient characterization.

中文翻译：

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自旋结构与孤立磁性布洛赫和尼尔斯格明子的相衬成像的关系

磁性斯格明子是具有大数据密度的未来存储设备的有希望的候选者。已经发现多种材料可以承载高达室温状态的斯格明子。洛伦兹显微镜通常在透射电子显微镜 (TEM) 中进行，是在现实空间中表征斯格明子样品的最重要工具之一。使用数值计算，这项工作将 TEM 中的相位对比与孤立的 Néel 或 Bloch 斯格明子（两种最常见的斯格明子类型）的实际磁化分布相关联。在使用的斯格明子模型的框架内，结果与斯格明子尺寸和壁宽以及纯磁性样品的样品厚度和比例无关。提供了简单的规则来提取纯 Bloch 或 Néel 斯格明子的实际斯格明子配置，而无需模拟。此外，还介绍了满足实验预期的 Néel skyrmions 的第一次微分相位对比 (DPC) 测量，并展示了所描述的原理。这项工作与材料科学相关，它可以通过方便的表征来设计斯格明子轮廓。