论文标题
Skyrmion系统中的Megahertz动力学用Muon-Spin放松探测
Megahertz dynamics in skyrmion systems probed with muon-spin relaxation
论文作者
论文摘要
我们在两个稳定Skyrmion晶格（SKL）的系统上进行了纵向场Muon-Spin放松（LF $ $ $ sr）：Cu $ _2 $ _2 $ _2 $ oseo $ _3 $，以及Co $ _x $ _x $ _x $ _x $ zn $ _y $ _y $ _y $ _ $ _ $ _ $ _} $ _ {20-x-x y} $ _ {20-x y} $（$（$）$（$（9） $（8,8）$。我们发现，Cu $ _2 $ OSEO $ _3 $的SKL阶段在Megahertz频率上展示了新兴的动态行为，这可能是由于集体激发而引起的，从而可以从$ $ $ SR的响应中识别出SKL。从遵循不同冷却协议的测量和MUON停止位点的计算中，我们建议亚稳态SKL并不是该材料整个材料的多数阶段，并且经常被观察到。 $ \ simeq〜2 $ GHz激发量的动力$ _8 $ _9 $ _9 $ _9 $ _3 $很好地描述了频率，而在临界温度附近的频率下降，而在CO $ _8 $ _8 $ _8 $ _8 $ _8 $ _4 $中，我们观察到类似的行为，在温度范围内相似，超越了这种动态，超越了这种动态的效果。
We present longitudinal-field muon-spin relaxation (LF $μ$SR) measurements on two systems that stabilize a skyrmion lattice (SkL): Cu$_2$OSeO$_3$, and Co$_x$Zn$_y$Mn$_{20-x-y}$ for $(x,y)~=~(10,10)$, $(8,9)$ and $(8,8)$. We find that the SkL phase of Cu$_2$OSeO$_3$ exhibits emergent dynamic behavior at megahertz frequencies, likely due to collective excitations, allowing the SkL to be identified from the $μ$SR response. From measurements following different cooling protocols and calculations of the muon stopping site, we suggest that the metastable SkL is not the majority phase throughout the bulk of this material at the fields and temperatures where it is often observed. The dynamics of bulk Co$_8$Zn$_9$Mn$_3$ are well described by $\simeq~2$ GHz excitations that reduce in frequency near the critical temperature, while in Co$_8$Zn$_8$Mn$_4$ we observe similar behavior over a wide range of temperatures, implying that dynamics of this kind persist beyond the SkL phase.
