We present a combined numerical, theoretical and experimental study on stimulated three-magnon splitting in a magnetic disk in the vortex equilibrium state. Our micromagnetic simulations and Brillouin-light-scattering results confirm that three-magnon splitting can be triggered even below threshold by exciting one of the secondary modes by magnons propagating in a waveguide next to the disk. The experiments show that stimulation is possible over an extended range of excitation powers and a wide range of frequencies around the eigenfrequencies of the secondary modes. Rate-equation calculations predict an instantaneous response to stimulation and the possibility to prematurely trigger three-magnon splitting even above threshold in a sustainable manner. These predictions are confirmed experimentally using time-resolved Brillouin-light-scattering measurements and are in a good qualitative agreement with the theoretical results. We believe that the controllable mechanism of stimulated three-magnon splitting could provide a possibility to utilize magnon-based nonlinear networks as hardware for reservoir or neuromorphic computing.
Nonlocal magnon-polaron transport in yttrium iron garnet
在磁绝缘体中观察到自旋塞贝克效应（SSE）|重金属双层作为温度梯度下的反自旋霍尔效应电压。也可以非局部地检测SSE，即，根据磁膜上的第二金属接触（检测器）中的电压，该第二金属接触在空间上与用于施加温度偏置的第一接触（注入器）分离。磁振子极化子是磁性材料中的晶格和自旋杂化波，由磁弹性相互作用产生。Kikkawa等人[Phys. Rev. Lett. \textbf{117}，207203（2016）]解释了钇铁石榴石（YIG）中局部SSE的共振增强作为磁振子-极化子形成方面的磁场的函数。本文报道了在不同注入器-探测器间距和样品温度下，在\emph{nonlocal}磁振子自旋注入/探测装置中对磁振子极化子的观测。出乎意料的是，我们发现磁振子-极化子共振可以抑制而不是增强非局域SSE。使用有限元模型，我们解释我们的观察作为一个竞争的SSE和自旋扩散YIG之间。这些结果为关键磁性材料中的磁振子-声子相互作用提供了前所未有的见解。
Nonlocal damping of spin waves in a magnetic insulator induced by normal, heavy, or altermagnetic metallic overlayer: A Schwinger-Keldysh field theory approach
