Department of Physics and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
Sci Rep. 2017 Jun 16;7(1):3660. doi: 10.1038/s41598-017-03832-4.
Unidirectional motion of magnetic structures such as the magnetic domain and domain walls is a key concept underlying next-generation memory and logic devices. As a potential candidate of such unidirectional motion, it has been recently demonstrated that the magnetic bubblecade-the coherent unidirectional motion of magnetic bubbles-can be generated by applying an alternating magnetic field. Here we report the optimal configuration of applied magnetic field for the magnetic bubblecade. The tilted alternating magnetic field induces asymmetric expansion and shrinkage of the magnetic bubbles under the influence of the Dzyaloshinskii-Moriya interaction, resulting in continuous shift of the bubbles in time. By examining the magnetic bubblecade in Pt/Co/Pt films, we find that the bubblecade speed is sensitive to the tilt angle with a maximum at an angle, which can be explained well by a simple analytical form within the context of the domain-wall creep theory. A simplified analytic formula for the angle for maximum speed is then given as a function of the amplitude of the alternating magnetic field. The present results provide a useful guideline of optimal design for magnetic bubblecade memory and logic devices.
磁结构（如磁畴和畴壁）的单向运动是下一代存储和逻辑器件的关键概念。作为这种单向运动的潜在候选者，最近已经证明，通过施加交变磁场可以产生磁泡列——磁泡的相干单向运动。在这里，我们报告了用于磁泡列的最佳外加磁场配置。倾斜的交变磁场在 Dzyaloshinskii-Moriya 相互作用的影响下引起磁泡的不对称膨胀和收缩，导致泡在时间上的连续移动。通过在 Pt/Co/Pt 薄膜中检查磁泡列，我们发现泡列速度对外加磁场的倾斜角很敏感，在一个角度处达到最大值，这可以通过畴壁蠕动理论的简单分析形式很好地解释。然后给出了最大速度角的简化解析公式，作为交变磁场幅度的函数。目前的结果为磁泡列存储和逻辑器件的最佳设计提供了有用的指导。
