Three-Dimensional Neutron Far-Field Tomography of a Bulk Skyrmion Lattice

M. E. Henderson; B. Heacock; M. Bleuel; D. G. Cory; C. Heikes; M. G. Huber; J. Krzywon; O. Nahman-Levesqué; G. M. Luke; M. Pula; D. Sarenac; K. Zhernenkov; D. A. Pushin

arXiv · 2208.00023

Three-Dimensional Neutron Far-Field Tomography of a Bulk Skyrmion Lattice

M. E. Henderson·B. Heacock·M. Bleuel·D. G. Cory·C. Heikes·M. G. Huber·J. Krzywon·O. Nahman-Levesqué·G. M. Luke·M. Pula·D. Sarenac·K. Zhernenkov·D. A. Pushin

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Abstract

Skyrmions are topologically-protected spin textures thought to nucleate and annihilate on points of vanishing magnetization, called Bloch points. However, owing to a lack of bulk techniques, experimental visualizations of skyrmion lattices and their stabilization through defects in three-dimensions remain elusive. Here, we present a tomographic algorithm applied to a Co$_8$Zn$_8$Mn$_4$ skyrmion lattice host, processing multi-projection small angle neutron scattering measurements to generate mean scattering feature reconstructions (MSFR) of the bulk spin textures. Digital phantoms validated the algorithm; reconstructions of the sample show a disordered skyrmion lattice with a topological saturation of 63~\%, exhibiting three-dimensional topological transitions through two different emergent (anti)monopole defect pathways with densities of 147~$\mu$m$^{-3}$ and 21~$\mu \mathrm{m}^{-3}$ for branching and segmentation events, respectively. Our techniques produce experimentally-informed visualizations of bulk skyrmion lattice structures and defects, enabling future bulk studies over a wide variety of sample shapes and chemistries, magnetic phases, and external parameters.

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M. E. Henderson, B. Heacock, M. Bleuel, D. G. Cory, C. Heikes, M. G. Huber, J. Krzywon, O. Nahman-Levesqué, G. M. Luke, M. Pula, D. Sarenac, K. Zhernenkov, D. A. Pushin. 2022-07-29. Three-Dimensional Neutron Far-Field Tomography of a Bulk Skyrmion Lattice. https://arxiv.org/abs/2208.00023

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