Operando study of chiral magnetic textures under electrical bias using Lorentz scanning transmission electron microscopy*

We develop a device fabrication process that is compatible with operando Lorentz Scanning Transmission Electron Microscopy (LSTEM) for studying chiral magnetic textures and their electric current dependent behavior with nanometer-scale spatial resolution. Chiral magnetic spin textures appear in our samples as a result of the interplay between magnetic energy terms including interfacial Dzyaloshinskii-Moriya Interaction and perpendicular magnetic anisotropy (PMA) at heavy metal/ferromagnet interfaces. High-resolution LSTEM can resolve the internal structure of spin textures including details as small as a few nm. As a first step, we examine stripe domain and field nucleated Néel Skyrmions in devices as we vary the stack repetition and ferromagnet thicknesses. We find rich magnetic textures with a strong history dependence as the magnitude of PMA approaches zero.