Slow steady flow of a skyrmion lattice in a confined geometry probed by narrow-band resistance noise-猫眼课题宝

DOI：

10.1103/physrevb.100.094410

发表时间：

2019-09

期刊：

Physical Review B

影响因子：

3.7

通讯作者：

中科院分区：

物理与天体物理2区

文献类型：

作者：

Takuro Sato;W. Koshibae;A. Kikkawa;T. Yokouchi;H. Oike;Y. Taguchi;N. Nagaosa;Y. Tokura;F. Kagawa

利用电阻涨落谱，我们观察到了微米级MnSi的磁天平-晶格相中的电流感生窄带噪声(NBN)。只有当电流密度超过阈值时，才会出现NBN，这表明电流驱动的Skyrmion晶格运动触发了NBN。在10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10×10NBN频率的温度演化表明，稳定的流动需要热激活过程，这很可能是由于样品边缘的Skyrmion产生和湮灭。考虑边界效应的数值模拟定性地支持了这一设想，它揭示了边界限制了天子的稳定流动，特别是在低温下。我们讨论了一种显著减缓微细加工样品中Skyrmion稳定流动的机制。

Using resistance fluctuation spectroscopy, we observe current-induced narrow-band noise (NBN) in the magnetic skyrmion-lattice phase of micrometer-sized MnSi. The NBN appears only when electric-current density exceeds a threshold value, indicating that the current-driven motion of the skyrmion lattice triggers the NBN. The observed NBN frequency is 10-10$^4$ Hz at $\sim$10$^{9}$ A/m$^{2}$, implying a skyrmion steady flow velocity of 1-100 $\mu$m/s, 3-5 orders of magnitude slower than previously reported. The temperature evolution of the NBN frequency suggests that the steady flow entails thermally activated processes, which are most likely due to skyrmion creation and annihilation at the sample edges. This scenario is qualitatively supported by our numerical simulations considering boundary effects, which reveals that the edges limit the steady flow of skyrmions, especially at low temperatures. We discuss a mechanism that dramatically slows the skyrmion steady flow in a microfabricated specimen.

Slow steady flow of a skyrmion lattice in a confined geometry probed by narrow-band resistance noise

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