Magnetic skyrmions are well-suited for encoding information because they are nano-sized, topologically stable, and only require ultra-low critical current densities j_c to depin from the underlying atomic lattice. Above j_c skyrmions exhibit well-controlled motion, making them prime candidates for race-track memories. In thin films thermally-activated creep motion of isolated skyrmions was observed below j_c as predicted by theory. Uncontrolled skyrmion motion is detrimental for race-track memories and is not fully understood. Notably, the creep of skyrmion lattices in bulk materials remains to be explored. Here we show using resonant ultrasound spectroscopy—a probe highly sensitive to the coupling between skyrmion and atomic lattices—that in the prototypical skyrmion lattice material MnSi depinning occurs at \({j}_{c}^{* }\) that is only 4 percent of j_c. Our experiments are in excellent agreement with Anderson-Kim theory for creep and allow us to reveal a new dynamic regime at ultra-low current densities characterized by thermally-activated skyrmion-lattice-creep with important consequences for applications.

磁性天生离子非常适合编码信息，因为它们是纳米级的，拓扑稳定的，并且仅需要超低的临界电流密度j _c即可与下面的原子晶格脱钩。在j _c以上，天体表现出良好的运动控制，使其成为赛道记忆的主要候选者。在薄膜中，在j _c以下观察到了孤立天sky的热激活蠕变运动如理论所预测。不受控制的天胶运动对赛道记忆是有害的，尚未完全理解。值得注意的是，散装材料中天rm子晶格的蠕变仍有待探索。在这里，我们示出了使用谐振超声光谱学，探针以skyrmion和原子之间的耦合高度敏感的晶格-的是，在原型skyrmion晶格材料锰硅脱钉发生在\（{Ĵ} _ {C} ^ {*} \） ，这只是j _c的4％。我们的实验与关于蠕变的Anderson-Kim理论非常吻合，使我们能够揭示一种以超低电流密度为特征的新动态机制，该特征以热激活的Skyrmion晶格蠕变为特征，并对应用产生重要影响。