Antiferromagnets (AFMs) have great benefits for spintronic applications such as high frequencies (up to THz), high speeds (up to tens of km/s) of magnetic excitations, and field-free operation. Advanced devices will require high-speed propagating spin waves (SWs) as signal carriers, i.e., SWs with high $k$ vectors, the excitation of which remains challenging. We show that a domain wall (DW) in anisotropic AFM driven by the spin current can be a source of such propagating SWs with high frequencies and group velocities. In the proposed generator, the spin current, with polarization directed along the easy anisotropy axis, excites the precession of the Néel vector within the DW. The threshold current is defined by the value of the anisotropy in the hard plane, and the frequency of the DW precession is tunable by the strength of the spin current. We show that the above precession of spins inside the DW leads to robust emission of high-frequency propagating SWs into the AFM strip with very short wavelengths comparable to the exchange length, which is hard to achieve by any other method.

中文翻译：

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自旋电流驱动的反铁磁畴壁发射快速传播的自旋波

反铁磁体 (AFM) 对于自旋电子学应用具有巨大优势，例如高频（高达太赫兹）、高速（高达数十公里/秒）磁激励和无场操作。先进的设备将需要高速传播的自旋波（SW）作为信号载体，即具有高$k$向量，其激发仍然具有挑战性。我们证明，由自旋电流驱动的各向异性 AFM 中的畴壁 (DW) 可以成为这种具有高频和群速度的传播 SW 的来源。在所提出的发生器中，自旋电流沿着易各向异性轴定向，激发 DW 内尼尔矢量的进动。阈值电流由硬平面中的各向异性值定义，并且 DW 进动的频率可通过自旋电流的强度进行调节。我们表明，DW 内的上述自旋进动导致高频传播 SW 强烈发射到 AFM 带中，其波长非常短，与交换长度相当，这是任何其他方法都难以实现的。