In spintronics, the propagation of spin-wave excitations in magnetically ordered materials can also be used to transport and process information. One of the most popular materials in this regard is the ferrimagnetic insulator yttrium iron garnet due its exceptionally small spin-wave damping parameter. While the small relaxation rate allows for large propagation length of magnetic excitations, it also leads to nonlocality of the magnetic properties. By imaging spin waves, their band structure is mapped with high-frequency resolution using a magneto-optic super-Nyquist sampling technique. In doing so, wave-vector selection is shown to suppress dispersion effects to a large extent, allowing for local measurements of spin relaxation. Moreover, we demonstrate even higher control of magnon propagation by employing the wave-vector selectivity near an avoided crossing of different spin-wave modes where the group velocity approaches zero. Here the local engineering of the dispersion allows us to construct magnonic waveguides, and at the same time it reveals the local relaxation properties.

中文翻译：

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钇铁石榴石中磁振子能带结构工程的自旋波定位与引导

在自旋电子学中，自旋波激发在磁性有序材料中的传播也可用于传输和处理信息。在这方面最受欢迎的材料之一是亚铁磁绝缘体钇铁石榴石，因为它的自旋波阻尼参数非常小。虽然小的弛豫率允许磁激发的大传播长度，但它也导致磁特性的非局域性。通过对自旋波进行成像，使用磁光超奈奎斯特采样技术以高频分辨率映射它们的带结构。在这样做时，波矢量选择被证明可以在很大程度上抑制色散效应，从而允许对自旋弛豫进行局部测量。而且，我们通过在群速度接近零的不同自旋波模式的避免交叉附近采用波矢量选择性，证明了对磁振子传播的更高控制。在这里，色散的局部工程允许我们构建磁波导，同时它揭示了局部弛豫特性。