Distinguished University Professor TOKURA Yoshinori’s Research Group Achieves World’s First Visualization of Skyrmion Strings 3D Shape
The research group to which Distinguished University Professor TOKURA Yoshinori belongs has succeeded in the direct visualization of the three-dimensional shape of skyrmion strings in a noncentrosymmetric magnet. The research result was published on Nature Materials online on 11 November 2021.
Magnetic skyrmions are topologically stable swirling spin textures that appear as particle-like objects in two-dimensional (2D) systems. Here, utilizing scalar magnetic X-ray tomography under applied magnetic fields, we report the direct visualization of the three-dimensional (3D) shape of individual skyrmion strings in the room-temperature skyrmion-hosting non-centrosymmetric compound Mn1.4Pt0.9Pd0.1Sn. Through the tomographic reconstruction of the 3D distribution of the  magnetization component on the basis of transmission images taken at various angles, we identify a skyrmion string running through the entire thickness of the sample, as well as various defect structures, such as the interrupted and Y-shaped strings. The observed point defect may represent the Bloch point serving as an emergent magnetic monopole, as proposed theoretically. Our tomographic approach with a tunable magnetic field paves the way for direct visualization of the structural dynamics of individual skyrmion strings in 3D space, which will contribute to a better understanding of the creation, annihilation and transfer of these topological objects.
The paper is available at https://www.nature.com/articles/s41563-021-01141-w and for more information, please refer to press release news (in Japanese).