Träger Nick, Groß Felix, Förster Johannes, Baumgaertl Korbinian, Stoll Hermann, Weigand Markus, Schütz Gisela, Grundler Dirk, Gräfe Joachim
Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
Laboratory of Nanoscale Magnetic Materials and Magnonics, Institute of Materials, EPFL, 1015, Lausanne, Switzerland.
Sci Rep. 2020 Oct 23;10(1):18146. doi: 10.1038/s41598-020-74785-4.
For understanding magnonic materials the fundamental characterization of their frequency response is essential. However, determining full dispersion relations and real space wavelength measurements are challenging and time-consuming tasks. We present an approach for spin wave excitation by a modified Sinc pulse, which combines a cosine signal with a conventional Sinc function. The resulting adjustable frequency bands lead to a broadband spin wave excitation at uniform power levels. Subsequently, time resolved scanning transmission X-ray microscopy is used for direct imaging of all excited spin waves in real space. To demonstrate the capabilities of this approach, a modified Sinc excitation of an ultra-thin yttrium-iron-garnet film is shown that simultaneously reveals phase, amplitude, and k-space information from a single measurement. Consequently, this approach allows a fast and thorough access to the full dispersion relation including spatial maps of the individual spin wave modes, enabling complete characterization of magnonic materials down to the nanoscale in real and reciprocal space.
为了理解磁振子材料，对其频率响应进行基本表征至关重要。然而，确定完整的色散关系和实空间波长测量是具有挑战性且耗时的任务。我们提出了一种通过改进的辛格脉冲进行自旋波激发的方法，该脉冲将余弦信号与传统的辛格函数相结合。由此产生的可调频带可在均匀功率水平下实现宽带自旋波激发。随后，利用时间分辨扫描透射X射线显微镜对实空间中所有激发的自旋波进行直接成像。为了证明这种方法的能力，展示了对超薄钇铁石榴石薄膜的改进辛格激发，其能从单次测量中同时揭示相位、幅度和k空间信息。因此，这种方法能够快速且全面地获取完整的色散关系，包括各个自旋波模式的空间图，从而能够在实空间和倒易空间中对磁振子材料进行直至纳米尺度的完整表征。
