二维磁性纳米条带中携带轨道角动量的自旋波的产生与调控

Generation and Manipulation of Spin Waves Carrying Orbital Angular Momentum in Two-Dimensional Magnetic Nanostrip

摘要: 近年来，在磁性材料中激发携带轨道角动量(OAM)的自旋波的研究吸引了广泛的关注。本研究使用微磁模拟方法，采用两种方案在坡莫合金纳米条带中激发携带横向轨道角动量的自旋波。一是使用叠加单向偏置磁场与振荡磁场的激励磁场在纳米条带中产生扭曲注自旋波。二是在纳米条带中心设置无涡核的磁涡旋态磁畴壁，通过其拓扑结构将平面波转换为扭曲自旋波。我们通过改变磁涡旋态的旋性和磁畴壁两侧磁矩的排列方式，实现对自旋波携带的OAM方向的调控，并且总结出磁涡旋态旋性与磁畴壁两侧磁矩的排列方式导致OAM方向反转的规律。我们的研究拓展并改良二维磁性纳米条带中产生携带OAM的自旋波的有效方法，并实现了对其方向的调控，为自旋波在信息传输和磁子器件中的应用提供了新思路和数据支持。

Abstract: In recent years, research on the excitation of spin waves carrying orbital angular momentum (OAM) in magnetic materials has attracted intense research interests. In this study, we employ micromagnetic simulation methods to excite spin waves carrying transverse orbital angular momentum which is perpendicular to the wave propagation direction in permalloy nanostrips, using two approaches. The first approach utilizes a combination of a biased unidirectional magnetic field and an oscillating magnetic field to generate distorted spin waves within the nanostrip. The second approach involves setting a magnetic vortex domain wall, without core, at the center of the nanostrip, where the topological structure converts plane waves into distorted spin waves. Furthermore, by altering the chirality of the magnetic vortex state and the arrangement of magnetic moments on both sides of the domain wall, the direction of the OAM carried by the spin waves is controlled. This reveals the mechanism by which the chirality of the magnetic vortex state and the arrangement of magnetic moments lead to the reversal of the OAM direction. Our research expands and improves effective methods for generating spin waves carrying OAM in two-dimensional magnetic nanostrips, achieving directional control. These findings provide new insights and data support for the application of spin waves in information transmission and magnetic devices.