Abstract We have comprehensively investigated asymmetric magnetization reversal behaviors of (x-A Co/7.7 A Pt)5 multilayers (x = 3.1 and 4.7) with perpendicular magnetic anisotropy. Our direct observation of magnetic domain structures by means of magneto-optical microscopy reveals that the asymmetry arises both from nucleation and wall-motion processes. An asymmetric nucleation behavior is observed, which could be originated from the preexisting non-reversed domains which might have a reproducible or random spatial distribution, controllable by tuning the field profile. An asymmetric wall-motion behavior stemming from asymmetric stripe domain evolution is also observed.

中文翻译：

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具有垂直磁各向异性的 Co/Pt 多层膜的不对称磁化反转的微观起源

摘要 我们全面研究了具有垂直磁各向异性的 (xA Co/7.7 A Pt)5 多层膜（x = 3.1 和 4.7）的不对称磁化反转行为。我们通过磁光显微镜对磁畴结构的直接观察表明，不对称性源于成核和壁运动过程。观察到不对称成核行为，这可能源自预先存在的非反转域，这些域可能具有可重复或随机的空间分布，可通过调整场分布进行控制。还观察到源自非对称条纹域演化的非对称壁运动行为。