论文标题
通过自旋轨道扭矩扩增沿Néel域壁的旋转波
Amplifying spin waves along Néel domain wall by spin-orbit torque
论文作者
论文摘要
Magnonic波导中的行进自旋波会经历严重的衰减，这往往会导致自旋波的有限繁殖长度，即使在可访问的最低阻尼常数的磁性材料中，严重限制了宏伟设备的发展。与传统波导中的自旋波相比，沿条状域壁传播的自旋波有望显示出增强的传播。在这里，我们在理论上和微磁模拟中证明了与铁磁/重金属双层相关的自旋轨道扭矩，尽管地面型磁化配置的复杂性，但沿着Néel-type带状域壁的自旋波沿Néel型带状域壁的衰减。应用于重金属层的电流方向决定了这些自旋波是放大还是进一步减弱。值得注意的是，我们的模拟表明，有效调整此类自旋波的衰减所需的有效电流密度仅为〜10^10 am-2，大约是一个小于常规自旋波导所需的阶。我们的结果将丰富用于宏伟技术的工具集。
Traveling spin waves in magnonic waveguides undergo severe attenuation, which tends to result in a finite propagation length of spin waves, even in magnetic materials with the accessible lowest damping constant, heavily restricting the development of magnonic devices. Compared with the spin waves in traditional waveguides, propagating spin waves along strip domain wall are expected to exhibit enhanced transmission. Here, we demonstrate, theoretically and through micromagnetic simulations, that spin-orbit torque associated with a ferromagnet/heavy metal bilayer can efficiently control the attenuation of spin waves along a Néel-type strip domain wall, despite the complexity in the ground-state magnetization configuration. The direction of the electric current applied to the heavy-metal layer determines whether these spin waves are amplified or further attenuated otherwise. Remarkably, our simulations reveal that the effective current densities required to efficiently tune the decay of such spin waves are just ~10^10 Am-2, roughly an order smaller than those required in conventional spin waveguides. Our results will enrich the toolset for magnonic technologies.
