Evidence for giant surface Dzyaloshinskii-Moriya interaction in the chiral magnetic insulator Cu2OSeO3

DOI: 10.1103/PhysRevB.109.L220402

Authors: Wancong Tan (ShanghaiTech University) , Haonan Jin (ShanghaiTech University) , Raymond Fan (Diamond Light Source) , Kejing Ran (ShanghaiTech University; Chongqing University) , Shilei Zhang (ShanghaiTech University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 109

State: Published (Approved)
Published: June 2024
Diamond Proposal Number(s): 30645

Abstract: Broken of translational symmetry plays a vital role in the stabilization of three-dimensional magnetic skyrmions. The absence of exchange neighbours at truncated surfaces leads to surface twist effect, resulting in twisted helicity angle of the skyrmions. Recently, it was reported in Zhang et al. [Proc. Natl. Acad. Sci. USA 115, 6386 (2018)] that the observed surface twist effect is over an order of magnitude more pronounced than the theoretical predictions. Nevertheless, the underlying mechanism that leads to such discrepancy has not been resolved yet. In order to address this long-standing issue, we performed depth-resolved circular dichroic resonant elastic x-ray scattering (CD-REXS) measurements on the skyrmion lattice phase in Cu2⁢OSeO3 over a wide temperature range. It is found that the measured skyrmion helicity angle profile is highly temperature-dependent, which cannot be quantitatively explained by the temperature-varying micromagnetic parameters alone. By systematically ruling out other possible effects, we conclude that a giant surface-type Dzyaloshinskii-Moriya interaction emerges due to the ferroelectric polarization at the surface of Cu2⁢OSeO3. Our results provide insights into the complex interplay between surface and bulk interactions in the formation of magnetic skyrmions and offer new possibilities for designing skyrmionic devices.

Diamond Keywords: Skyrmions

Subject Areas: Materials, Physics, Information and Communication Technology

Diamond Offline Facilities: RASOR
Instruments: I10-Beamline for Advanced Dichroism - scattering

Added On: 08/06/2024 15:47

Discipline Tags:

Surfaces Quantum Materials Physics Hard condensed matter - structures Information & Communication Technologies Magnetism Materials Science

Technical Tags:

Scattering Resonant Elastic X-ray Scattering (REXS)