Dreyer Rouven, Liebing Niklas, Edwards Eric R J, Müller Andreas, Woltersdorf Georg
Institute of Physics, Martin Luther University Halle-Wittenberg, 06120 Halle, Germany.
Phys Rev Mater. 2021;5(6). doi: 10.1103/physrevmaterials.5.064411.
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 non-locality of the magnetic properties. By imaging spin waves their band structure is mapped. 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 local engineering of the dispersion allows constructing magnonic waveguides and at the same time reveals the local relaxation properties.
在自旋电子学中，磁有序材料中自旋波激发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，因为其自旋波阻尼参数异常小。虽然小的弛豫率允许磁激发有较大的传播长度，但它也导致了磁特性的非局域性。通过对自旋波成像，可以绘制出它们的能带结构。这样做时，波矢选择被证明在很大程度上抑制了色散效应，从而允许对自旋弛豫进行局部测量。此外，我们通过在不同自旋波模式的避免交叉附近利用波矢选择性来证明对磁振子传播有更高的控制，在该交叉处群速度趋近于零。在这里，色散的局部工程允许构建磁振子波导，同时揭示局部弛豫特性。
