NanoSpin, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, FI-00076, Aalto, Finland.
Dipartimento di Fisica e Geologia, Università di Perugia, 06123, Perugia, Italy.
Nat Commun. 2018 Nov 19;9(1):4853. doi: 10.1038/s41467-018-07372-x.
Active manipulation of spin waves is essential for the development of magnon-based technologies. Here, we demonstrate programmable spin-wave filtering by resetting the spin structure of pinned 90° Néel domain walls in a continuous CoFeB film with abrupt rotations of uniaxial magnetic anisotropy. Using micro-focused Brillouin light scattering and micromagnetic simulations, we show that broad 90° head-to-head or tail-to-tail magnetic domain walls are transparent to spin waves over a broad frequency range. In contrast, magnetic switching to a 90° head-to-tail configuration produces much narrower and strongly reflecting domain walls at the same pinning locations. Based on these results, we propose a magnetic spin-wave valve with two parallel domain walls. Switching the spin-wave valve from an open to a closed state changes the transmission of spin waves from nearly 100 to 0%. Active control over spin-wave transport through programmable domain walls could be utilized in magnonic logic devices or non-volatile memory elements.
自旋波的主动操控对于基于磁振子的技术发展至关重要。在这里，我们通过在连续的 CoFeB 薄膜中突然旋转各向异性轴，重置被钉扎的 90°奈尔域壁的自旋结构，展示了可编程的自旋波滤波。利用微聚焦布里渊光散射和微磁模拟，我们表明，在较宽的频率范围内，宽的 90°对头或尾对尾磁畴壁对自旋波是透明的。相比之下，磁切换到 90°对头构型会在相同的钉扎位置产生更窄且强烈反射的畴壁。基于这些结果，我们提出了一种具有两个平行畴壁的磁自旋波阀。将自旋波阀从打开状态切换到关闭状态会使自旋波的传输从近 100%变为 0%。通过可编程畴壁对自旋波输运的主动控制可应用于磁振子逻辑器件或非易失性存储元件中。
