Schoenherr Peggy, Stepanova Mariia, Lysne Erik Nikolai, Kanazawa Naoya, Tokura Yoshinori, Bergman Anders, Meier Dennis
Department of Materials, ETH Zürich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia.
ACS Nano. 2021 Nov 23;15(11):17508-17514. doi: 10.1021/acsnano.1c04302. Epub 2021 Oct 19.
The formation of topological spin textures at the nanoscale has a significant impact on the long-range order and dynamical response of magnetic materials. We study the relaxation mechanisms at the conical-to-helical phase transition in the chiral magnet FeGe. By combining macroscopic ac susceptibility measurement, surface-sensitive magnetic force microscopy, and micromagnetic simulations, we demonstrate how the motion of magnetic topological defects, here edge dislocations, impacts the local formation of a stable helimagnetic spin structure. Although the simulations show that the edge dislocations can move with a velocity up to 100 m/s through the helimagnetic background, their dynamics are observed to disturb the magnetic order on the time scale of minutes due to randomly distributed pinning sites. The results corroborate the substantial impact of dislocation motions on the nanoscale spin structure in chiral magnets, revealing previously hidden effects on the formation of helimagnetic domains and domain walls.
纳米尺度拓扑自旋纹理的形成对磁性材料的长程序和动力学响应有重大影响。我们研究了手性磁体FeGe中从锥形到螺旋相转变的弛豫机制。通过结合宏观交流磁化率测量、表面敏感磁力显微镜和微磁模拟，我们展示了磁性拓扑缺陷（此处为刃型位错）的运动如何影响稳定螺旋磁自旋结构的局部形成。尽管模拟表明刃型位错可以在螺旋磁背景中以高达100 m/s的速度移动，但由于随机分布的钉扎位点，观察到它们的动力学在几分钟的时间尺度上会扰乱磁序。这些结果证实了位错运动对手性磁体纳米尺度自旋结构的重大影响，揭示了以前对螺旋磁畴和畴壁形成隐藏的影响。
