Excitation and detection of coherent sub-terahertz magnons in ferromagnetic and antiferromagnetic heterostructures
Excitation and detection of coherent sub-terahertz magnons in ferromagnetic and antiferromagnetic heterostructures
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DOI：
10.1038/s41524-022-00851-2
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发表时间：
2021-12
影响因子：
9.7
通讯作者：
S. Zhuang;Jiangsheng Hu
中科院分区：
文献类型：
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作者：
S. Zhuang;Jiangsheng Hu
相干高频磁振子（自旋波量子）的激发对于高速磁振子器件的发展至关重要。在这里，我们通过计算证明了光致皮秒声脉冲对铁磁（FM）和反铁磁（AFM）薄膜中相干亚太赫兹（THz）磁振子的激发。还进行了分析计算以揭示磁振子激发机制。通过自旋泵浦和自旋电荷转换，这些磁振子可以将亚太赫兹充电电流注入相邻的重金属薄膜，从而发射电磁（EM）波。使用考虑声波、自旋波和电磁波耦合动力学的动态相场模型，我们表明发射的电磁波保留了所有亚太赫兹磁振子模式的光谱信息，并且具有足够大的振幅用于近场检测。这些预测表明，亚太赫兹磁振子的激发和检测可以通过超快光泵太赫兹发射探针光谱在合理设计的 FM 或 AFM 薄膜异质结构中实现。
Excitation of coherent high-frequency magnons (quanta of spin waves) is critical to the development of high-speed magnonic devices. Here we computationally demonstrate the excitation of coherent sub-terahertz (THz) magnons in ferromagnetic (FM) and antiferromagnetic (AFM) thin films by a photoinduced picosecond acoustic pulse. Analytical calculations are also performed to reveal the magnon excitation mechanism. Through spin pumping and spin-charge conversion, these magnons can inject sub-THz charge current into an adjacent heavy-metal film which in turn emits electromagnetic (EM) waves. Using a dynamical phase-field model that considers the coupled dynamics of acoustic waves, spin waves, and EM waves, we show that the emitted EM wave retains the spectral information of all the sub-THz magnon modes and has a sufficiently large amplitude for near-field detection. These predictions indicate that the excitation and detection of sub-THz magnons can be realized in rationally designed FM or AFM thin-film heterostructures via ultrafast optical-pump THz-emission-probe spectroscopy.