Dynamics and formation of antiferromagnetic textures in MnBi$_2$Te$_4$ single crystal

Fuente: arXiv
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Main Authors: Kim, M. G., Boney, S., Burgard, L., Rutowski, L., Mazzoli, C.
Format: Preprint
Published: 2025
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_version_ 1866914114562949120
author Kim, M. G.
Boney, S.
Burgard, L.
Rutowski, L.
Mazzoli, C.
author_facet Kim, M. G.
Boney, S.
Burgard, L.
Rutowski, L.
Mazzoli, C.
contents We report coherent X-ray imaging of antiferromagnetic (AFM) domains and domain walls in MnBi$_2$Te$_4$, an intrinsic AFM topological insulator. This technique enables direct visualization of domain morphology without reconstruction algorithms, allowing us to resolve antiphase domain walls as distinct dark lines arising from the A-type AFM structure. The wall width is determined to be 550(30) nm, in good agreement with earlier magnetic force microscopy results. The temperature dependence of the AFM order parameter extracted from our images closely follows previous neutron scattering data. Remarkably, however, we find a pronounced hysteresis in the evolution of domains and domain walls: upon cooling, dynamic reorganizations occur within a narrow $\sim$1 K interval below $T_N$, whereas upon warming, the domain configuration remains largely unchanged until AFM order disappears. These findings reveal a complex energy landscape in MnBi$_2$Te$_4$, governed by the interplay of exchange, anisotropy, and domain-wall energies, and underscore the critical role of AFM domain-wall dynamics in shaping its physical properties.
format Preprint
id arxiv_https___arxiv_org_abs_2510_22051
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamics and formation of antiferromagnetic textures in MnBi$_2$Te$_4$ single crystal
Kim, M. G.
Boney, S.
Burgard, L.
Rutowski, L.
Mazzoli, C.
Materials Science
Strongly Correlated Electrons
We report coherent X-ray imaging of antiferromagnetic (AFM) domains and domain walls in MnBi$_2$Te$_4$, an intrinsic AFM topological insulator. This technique enables direct visualization of domain morphology without reconstruction algorithms, allowing us to resolve antiphase domain walls as distinct dark lines arising from the A-type AFM structure. The wall width is determined to be 550(30) nm, in good agreement with earlier magnetic force microscopy results. The temperature dependence of the AFM order parameter extracted from our images closely follows previous neutron scattering data. Remarkably, however, we find a pronounced hysteresis in the evolution of domains and domain walls: upon cooling, dynamic reorganizations occur within a narrow $\sim$1 K interval below $T_N$, whereas upon warming, the domain configuration remains largely unchanged until AFM order disappears. These findings reveal a complex energy landscape in MnBi$_2$Te$_4$, governed by the interplay of exchange, anisotropy, and domain-wall energies, and underscore the critical role of AFM domain-wall dynamics in shaping its physical properties.
title Dynamics and formation of antiferromagnetic textures in MnBi$_2$Te$_4$ single crystal
topic Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2510.22051