We demonstrate the formation of metastable Neel-type Skyrmions in Pt/Co/Ni/Ir multi-layers at remanence through \textit{ex situ} application of an in-plane magnetic field using Lorentz transmission electron microscopy (TEM). The resultant Skyrmion texture is found to depend on both the strength and misorientation of the applied field as well as the interfacial Dzyaloshinskii-Moriya interaction (DMI). To demonstrate the importance of the applied field angle, we leverage bend contours in the TEM specimens which coincide with transition regions between Skyrmion and labyrinth patterns. Subsequent application of a perpendicular magnetic field near the bent regions leads to the unusual situation where Neel Skyrmions with opposite magnetic polarities are stabilized in close proximity. Our results are discussed in the context of a critical saturation field, $H_{\text{K}}^{\ast}$, for destabilizing magnetic stripe patterns -- a theory previously applied to uniaxial bubble materials. The significant interfacial DMI in our samples is expected to reduce $H_{\text{K}}^{\ast}$ and also suppress the driving force for Skyrmions to coalesce back into a labyrinth pattern.

中文翻译：

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非对称超晶格中零场斯格明子阵列的形成

我们通过使用洛伦兹透射电子显微镜 (TEM) 的面内磁场的 \textit{ex situ} 应用证明了在剩磁的 Pt/Co/Ni/Ir 多层中亚稳态 Neel 型 Skyrmions 的形成。发现所得的 Skyrmion 纹理取决于外加场的强度和方向错误以及界面 Dzyaloshinskii-Moriya 相互作用 (DMI)。为了证明外加场角的重要性，我们利用 TEM 样品中的弯曲轮廓与 Skyrmion 和迷宫图案之间的过渡区域重合。随后在弯曲区域附近施加垂直磁场会导致异常情况，即具有相反磁极性的 Neel Skyrmions 在附近稳定。我们的结果是在临界饱和场 $H_{\text{K}}^{\ast}$ 的背景下讨论的，用于破坏磁条图案的稳定性——以前应用于单轴气泡材料的理论。我们的样品中显着的界面 DMI 预计会减少 $H_{\text{K}}^{\ast}$ 并抑制 Skyrmions 合并回迷宫图案的驱动力。