All-optical switching of magnetic materials is a potential method for realizing high-efficiency and high-speed data writing in spintronics devices. The current method, which utilizes two circular helicities of light to manipulate magnetic domains, is based on femtosecond pulsed lasers. In this study, we demonstrate a new all-optical switching method using a continuous-wave Laguerre–Gaussian beam (twisted light), which allows photons to carry orbital angular momentum with discrete levels, ℏ, to modify the magnetic anisotropy of an interlayer exchange coupling system. The easy axis of the heterojunction Pt(5 nm)/Co(1.2 nm)/Ru(1.4 nm)/Co(0.4 nm)/Pt(5 nm) on a SiO₂/Si substrate dramatically changed after illuminating it with a laser beam carrying a sufficient quantum number of orbital angular momentum. Based on a simple numerical calculation, we deduced that the interaction between the dynamical phase rotation of the electric field and the metal surface could generate an in-plane circular current loop that consequently induces a perpendicular stray field to change the magnetic anisotropy. This finding paves the way for developments in the field of magnetic-based spintronics using light with orbital angular momentum.

中文翻译：

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层间交换耦合系统中扭曲光引起的磁各向异性变化

磁性材料的全光切换是在自旋电子设备中实现高效，高速数据写入的一种潜在方法。当前的方法利用飞秒脉冲激光器来利用两个圆形的光螺旋来操纵磁畴。在这项研究中，我们展示了一个新的全光学切换方法使用连续波拉盖尔-高斯光束（扭曲光），它允许光子携带用离散电平，轨道角动量ℏ，修改一个层间交换的磁各向异性耦合系统。SiO ₂上异质结Pt（5 nm）/ Co（1.2 nm）/ Ru（1.4 nm）/ Co（0.4 nm）/ Pt（5 nm）的易轴用载有足够量子数量的轨道角动量的激光束照射后，/ Si衬底发生了巨大变化。基于简单的数值计算，我们推论出电场的动态相位旋转与金属表面之间的相互作用会产生平面内的圆形电流回路，从而引起垂直的杂散场，从而改变磁各向异性。这一发现为使用具有轨道角动量的光的磁性自旋电子学领域的发展铺平了道路。