Zn取代Skyrmion基质Cu $_2$ OSeO $_3$的旋磁相变的钉扎
Pinning of Helimagnetic Phase Transitions in Zn-Substituted Skyrmion Host Cu$_2$OSeO$_3$
摘要：
磁skyrmions是纳米尺寸的拓扑自旋纹理稳定的磁能项的微妙平衡。Skyrmion宿主材料的潜在晶体结构的化学取代提供了一种操纵这些能量贡献的途径，但也引入了额外的效应，如无序和钉扎。虽然在B20金属材料如Fe $_{1-x}$ Co $_x$ Si和Mn $_{1-x}$ Fe $_x$ Si中已经很好地研究了掺杂和无序的影响，但是在磁电绝缘体Cu $_2$ OSeO $_3$中化学取代的结果还没有被充分地探索。在这项工作中，我们利用交流磁测量和小角中子散射相结合，研究在原始和Zn取代的Cu $_2$ OSeO $_3$的磁相变动力学。结果表明，一级螺旋-圆锥相变表现出两个热分离的行为区域：在高温下，螺旋磁畴通过大尺度连续旋转转变，而在低温下，两相共存。值得注意的是，尽管可用的热活化能降低，但与高温相比，取代样品中的钉扎效应在低温下不太普遍。我们将这种行为归因于大的，温度依赖性，立方各向异性独特的铜$_2$ OSeO $_3$，它变得足够强大，以克服在低温下的钉扎能。考虑和进一步探索这些影响将是至关重要的工程skyrmion材料对未来的应用。
英文摘要：
Magnetic skyrmions are nano-sized topological spin textures stabilized by a delicate balance of magnetic energy terms. The chemical substitution of the underlying crystal structure of skyrmion-hosting materials offers a route to manipulate these energy contributions, but also introduces additional effects such as disorder and pinning. While the effects of doping and disorder have been well studied in B20 metallic materials such as Fe$_{1-x}$Co$_x$Si and Mn$_{1-x}$Fe$_x$Si, the consequences of chemical substitution in the magnetoelectric insulator Cu$_2$OSeO$_3$ have not been fully explored. In this work, we utilize a combination of AC magnetometry and small angle neutron scattering to investigate the magnetic phase transition dynamics in pristine and Zn-substituted Cu$_2$OSeO$_3$. The results demonstrate that the first order helical-conical phase transition exhibits two thermally separated behavioural regimes: at high temperatures, the helimagnetic domains transform by large-scale, continuous rotations, while at low temperatures, the two phases coexist. Remarkably, the effects of pinning in the substituted sample are less prevalent at low temperatures, compared to high temperatures, despite the reduction of available thermal activation energy. We attribute this behaviour to the large, temperature-dependent, cubic anisotropy unique to Cu$_2$OSeO$_3$, which becomes strong enough to overcome the pinning energy at low temperatures. Consideration and further exploration of these effects will be crucial when engineering skyrmion materials towards future applications.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
