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  • Letter
  • Open Access

Direct observation of exchange anisotropy in the helimagnetic insulator Cu2OSeO3

Priya R. Baral1,2,3,*, Oleg I. Utesov4, Chen Luo5, Florin Radu5, Arnaud Magrez1, Jonathan S. White3, and Victor Ukleev5,6,†

  • 1Crystal Growth Facility, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
  • 2Chair of Computational Condensed Matter Physics, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
  • 3Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
  • 4Center for Theoretical Physics of Complex Systems, Institute for Basic Science, Daejeon 34126, Republic of Korea
  • 5Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany
  • 6Swiss Light Source, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland

  • *priya.baral@psi.ch
  • †victor.ukleev@helmholtz-berlin.de
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Phys. Rev. Research 5, L032019 – Published 9 August, 2023

DOI: https://doi.org/10.1103/PhysRevResearch.5.L032019

Abstract

The helical magnetic structures of cubic chiral systems are well explained by the competition among Heisenberg exchange, Dzyaloshinskii-Moriya interaction, cubic anisotropy, and anisotropic exchange interaction (AEI). Recently, the role of the latter has been argued theoretically to be crucial for the low-temperature phase diagram of the cubic chiral magnet Cu2OSeO3, which features tilted conical and disordered skyrmion states for a specific orientation of the applied magnetic field (μ0H⃗∥[001]). In this study, we exploit transmission resonant x-ray scattering in vector magnetic fields to directly quantify the strength of the AEI in Cu2OSeO3 and measure its temperature dependence. We find that the AEI continuously increases below 50 K, resulting in a conical spiral pitch variation of 10% in the (001) plane. Our results contribute to establishing the interaction space that supports tilted cone and low-temperature skyrmion state formation, facilitating the goals for both a quantitative description and eventual design of the diverse spiral states existing amongst chiral magnets.

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Phys. Rev. Research 5, L032019– Published 9 August, 2023
  • Received 2 March 2023
  • Accepted 6 June 2023
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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