A surface-confined spiral state with the double period in the cubic chiral helimagnet Cu2OSeO3
Abstract The chiral magnetoelectric insulator Cu 2 OSeO 3 hosts a rich and anisotropic magnetic phase diagram that includes helical, conical, field-polarised, tilted conical, and skyrmion lattice phases. Using resonant elastic x-ray scattering (REXS), we uncover a new spiral state confined to the surface of Cu 2 OSeO 3 . This surface-confined spiral state (SSS) displays a real-space pitch of ~ 120 nm, which remarkably is twice the length of the incommensurate structures observed to-date in Cu 2 OSeO 3 . The SSS phase emerges at temperatures below 30 K when the magnetic field is applied between 3 ∘ to 18 ∘ away from the 〈110〉 crystallographic axes. Its surface localisation is demonstrated through a combination of REXS in reflection and transmission geometries, with complementary small-angle neutron scattering measurements suggesting its absence from the bulk. We attribute the stabilisation of the SSS to competing anisotropic interactions at the crystal surface. The discovery of a robust, surface-confined spiral paves the way for engineering energy-efficient, nanoscale spin-texture platforms for next-generation devices.
Authors
- Nina‐Juliane Steinke (ORCID: https://orcid.org/0000-0002-0207-6071)
- Oleg I. Utesov (ORCID: https://orcid.org/0000-0003-0910-5274)
- F. Radu (ORCID: https://orcid.org/0000-0003-0284-7937)
- Pierluigi Gargiani (ORCID: https://orcid.org/0000-0002-6649-0538)
- Victor Ukleev (ORCID: https://orcid.org/0000-0003-3703-264X)
- Samuel H. Moody
- Arnaud Magrez (ORCID: https://orcid.org/0000-0001-5933-7036)
- Priya R. Baral (ORCID: https://orcid.org/0000-0002-9755-6165)
- Matthew T. Littlehales
- R. Cubitt (ORCID: https://orcid.org/0000-0003-1778-3307)
- Manuel Valvidares (ORCID: https://orcid.org/0000-0003-4895-8114)
- Chen Luo (ORCID: https://orcid.org/0000-0001-6476-9116)
- Jonathan White (ORCID: https://orcid.org/0000-0001-5254-506X)
Institutions
- Rutherford Appleton Laboratory (GB)
- Durham University (GB)
- Helmholtz-Zentrum Berlin für Materialien und Energie (DE)
- ALBA Synchrotron (Spain) (ES)
- Paul Scherrer Institute (CH)
- Institute for Basic Science (KR)
- Institut Laue-Langevin (FR)
- École Polytechnique Fédérale de Lausanne (CH)
- The University of Tokyo (JP)
Publication Details
- Journal
- npj Quantum Materials
- Published
- 2026-05-21
- DOI
- https://doi.org/10.1038/s41535-026-00892-6
- Primary Topic
- Advanced Condensed Matter Physics
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Deutsche Forschungsgemeinschaft
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Institute for Basic Science