Competing anisotropies in the chiral cubic magnet Co$_8$Zn$_8$Mn$_4$ unveiled by resonant x-ray magnetic scattering

Fuente: arXiv
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Autores principales: Ukleev, Victor, Utesov, Oleg I., Luo, Chen, Radu, Florin, Wintz, Sebastian, Weigand, Markus, Finizio, Simone, Winter, Moritz, Tahn, Alexander, Rellinghaus, Bernd, Karube, Kosuke, Tokura, Yoshinori, Taguchi, Yasujiro, White, Jonathan S.
Formato: Preprint
Publicado: 2024
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author Ukleev, Victor
Utesov, Oleg I.
Luo, Chen
Radu, Florin
Wintz, Sebastian
Weigand, Markus
Finizio, Simone
Winter, Moritz
Tahn, Alexander
Rellinghaus, Bernd
Karube, Kosuke
Tokura, Yoshinori
Taguchi, Yasujiro
White, Jonathan S.
author_facet Ukleev, Victor
Utesov, Oleg I.
Luo, Chen
Radu, Florin
Wintz, Sebastian
Weigand, Markus
Finizio, Simone
Winter, Moritz
Tahn, Alexander
Rellinghaus, Bernd
Karube, Kosuke
Tokura, Yoshinori
Taguchi, Yasujiro
White, Jonathan S.
contents The cubic $β$-Mn-type alloy Co$_8$Zn$_8$Mn$_4$ is a chiral helimagnet that exhibits a peculiar temperature-dependent behavior in the spiral pitch, which decreases from 130 nm at room temperature to 70 nm below 20 K. Notably, this shortening is also accompanied by a structural transition of the metastable skyrmion texture, transforming from a hexagonal lattice to a square lattice of elongated skyrmions. The underlying mechanism of these transformations remain unknown, with interactions potentially involved including temperature-dependent Dzyaloshinskii-Moriya interaction, magnetocrystalline anisotropy, and exchange anisotropy. Here, x-ray resonant magnetic small-angle scattering in vectorial magnetic fields was employed to investigate the temperature dependence of the anisotropic properties of the helical phase in Co$_8$Zn$_8$Mn$_4$. Our results reveal quantitatively that the magnitude of the anisotropic exchange interaction increases by a factor of 4 on cooling from room temperature to 20 K, leading to a 5% variation in the helical pitch within the (001) plane at 20 K. While anisotropic exchange interaction contributes to the shortening of the spiral pitch, its magnitude is insufficient to explain the variation in the spiral periodicity from room to low temperatures. Finally, we demonstrate that magnetocrystalline and exchange anisotropies compete, favoring different orientations of the helical vector in the ground state.
format Preprint
id arxiv_https___arxiv_org_abs_2404_14697
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Competing anisotropies in the chiral cubic magnet Co$_8$Zn$_8$Mn$_4$ unveiled by resonant x-ray magnetic scattering
Ukleev, Victor
Utesov, Oleg I.
Luo, Chen
Radu, Florin
Wintz, Sebastian
Weigand, Markus
Finizio, Simone
Winter, Moritz
Tahn, Alexander
Rellinghaus, Bernd
Karube, Kosuke
Tokura, Yoshinori
Taguchi, Yasujiro
White, Jonathan S.
Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
The cubic $β$-Mn-type alloy Co$_8$Zn$_8$Mn$_4$ is a chiral helimagnet that exhibits a peculiar temperature-dependent behavior in the spiral pitch, which decreases from 130 nm at room temperature to 70 nm below 20 K. Notably, this shortening is also accompanied by a structural transition of the metastable skyrmion texture, transforming from a hexagonal lattice to a square lattice of elongated skyrmions. The underlying mechanism of these transformations remain unknown, with interactions potentially involved including temperature-dependent Dzyaloshinskii-Moriya interaction, magnetocrystalline anisotropy, and exchange anisotropy. Here, x-ray resonant magnetic small-angle scattering in vectorial magnetic fields was employed to investigate the temperature dependence of the anisotropic properties of the helical phase in Co$_8$Zn$_8$Mn$_4$. Our results reveal quantitatively that the magnitude of the anisotropic exchange interaction increases by a factor of 4 on cooling from room temperature to 20 K, leading to a 5% variation in the helical pitch within the (001) plane at 20 K. While anisotropic exchange interaction contributes to the shortening of the spiral pitch, its magnitude is insufficient to explain the variation in the spiral periodicity from room to low temperatures. Finally, we demonstrate that magnetocrystalline and exchange anisotropies compete, favoring different orientations of the helical vector in the ground state.
title Competing anisotropies in the chiral cubic magnet Co$_8$Zn$_8$Mn$_4$ unveiled by resonant x-ray magnetic scattering
topic Mesoscale and Nanoscale Physics
Materials Science
Strongly Correlated Electrons
url https://arxiv.org/abs/2404.14697