TY - JOUR
AU - Arjun Rana
AU - Chen-Ting Liao
AU - Ezio Iacocca
AU - Ji Zou
AU - Minh Pham
AU - Emma-Elizabeth Subramanian
AU - Yuan Lo
AU - Sinéad Ryan
AU - Xingyuan Lu
AU - Charles Bevis
AU - Robert Karl Jr
AU - Andrew Glaid
AU - Young-Sang Yu
AU - Pratibha Mahale
AU - David Shapiro
AU - Sadegh Yazdi
AU - Thomas Mallouk
AU - Stanley Osher
AU - Henry Kapteyn
AU - Vincent Crespi
AU - John Badding
AU - Yaroslav Tserkovnyak
AU - Margaret Murnane
AU - Jianwei Miao
AB - Magnetic topological defects are energetically stable spin configurations characterized by symmetry breaking. Vortices and skyrmions are two well-known examples of 2D spin textures that have been actively studied for both fundamental interest and practical applications. However, experimental evidence of the 3D spin textures has been largely indirect or qualitative to date, due to the difficulty of quantitively characterizing them within nanoscale volumes. Here, we develop soft x-ray vector ptychography to quantitatively image the 3D magnetization vector field in a frustrated superlattice with 10 nm spatial resolution. By applying homotopy theory to the experimental data, we quantify the topological charge of hedgehogs and anti-hedgehogs as emergent magnetic monopoles and probe their interactions inside the frustrated superlattice. We also directly observe virtual hedgehogs and anti-hedgehogs created by magnetically inert voids. We expect that this new quantitative imaging method will open the door to study 3D topological spin textures in a broad class of magnetic materials. Our work also demonstrates that magnetically frustrated superlattices could be used as a new platform to investigate hedgehog interactions and dynamics and to exploit optimized geometries for information storage and transport applications.
BT - Submitted
N2 - Magnetic topological defects are energetically stable spin configurations characterized by symmetry breaking. Vortices and skyrmions are two well-known examples of 2D spin textures that have been actively studied for both fundamental interest and practical applications. However, experimental evidence of the 3D spin textures has been largely indirect or qualitative to date, due to the difficulty of quantitively characterizing them within nanoscale volumes. Here, we develop soft x-ray vector ptychography to quantitatively image the 3D magnetization vector field in a frustrated superlattice with 10 nm spatial resolution. By applying homotopy theory to the experimental data, we quantify the topological charge of hedgehogs and anti-hedgehogs as emergent magnetic monopoles and probe their interactions inside the frustrated superlattice. We also directly observe virtual hedgehogs and anti-hedgehogs created by magnetically inert voids. We expect that this new quantitative imaging method will open the door to study 3D topological spin textures in a broad class of magnetic materials. Our work also demonstrates that magnetically frustrated superlattices could be used as a new platform to investigate hedgehog interactions and dynamics and to exploit optimized geometries for information storage and transport applications.
PY - 2022
T2 - Submitted
TI - Direct observation of 3D topological spin textures and their interactions using soft x-ray vector ptychography
UR - https://arxiv.org/abs/2104.12933
ER -