Chiral surface spin textures in Cu${}_2$OSeO${}_3$ unveiled by soft x-ray scattering in specular reflection geometry

Abstract

Resonant elastic soft x-ray magnetic scattering (XRMS) is a powerful tool to explore long-periodic spin textures in single crystals. However, due to the limited momentum transfer range imposed by long wavelengths of photons in the soft x-ray region, Bragg diffraction is restricted to crystals with the large lattice parameters. Alternatively, small angle x-ray scattering has been involved in the soft energy x-ray range which, however, brings in difficulties with the sample preparation that involves focused ion beam milling to thin down the crystal to below a few hundred nm thickness. We show how to circumvent these restrictions by using XRMS in specular reflection from a sub-nanometer smooth crystal surface. The method allows observing diffraction peaks from the helical and conical spin modulations at the surface of a Cu${}_2$OSeO${}_3$ single crystal and probing their corresponding chirality as contributions to the dichroic scattered intensity. The results suggest a promising way to carry out XRMS studies on plethora of noncentrosymmetric systems hitherto unexplored with soft x-rays due to the absence of the commensurate Bragg peaks in the available momentum transfer range.

11 pages, 5 figures

References in corpus (13)

• Advances in the Physics of Magnetic Skyrmions and Perspective for Technology
• A new class of chiral materials hosting magnetic skyrmions beyond room temperature
• Néel-type skyrmion lattice in tetragonal polar magnet VOSe${}_2$O${}_5$
• Resonant Elastic Soft X-Ray Scattering
• Observation of two independent skyrmion phases in a chiral magnetic material
• Room-temperature antiskyrmions and sawtooth surface textures in a noncentrosymmetric magnet with $S_4$ symmetry
• Chirality in magnetic multilayers probed by the symmetry and the amplitude of dichroism in X-ray resonant magnetic scattering
• Surface sensitivity of the spin Seebeck effect
• Microwave spectroscopy of the low-temperature skyrmion state in Cu2OSeO3
• Element-specific soft X-ray spectroscopy, scattering and imaging studies of skyrmion-hosting compound Co${}_8$Zn${}_8$Mn${}_4$
• Field-induced reorientation of helimagnetic order in Cu${}_2$OSeO${}_3$ probed by magnetic force microscopy
• Conical spin order with chiral quadrupole helix in CsCuCl3
• Growth and helicity of non-centrosymmetric Cu${}_2$OSeO${}_3$ crystals

Cited by in corpus (4)

• Direct observation of Néel-type skyrmions and domain walls in a ferrimagnetic DyCo${}_3$ thin film
• Observation by SANS and PNR of pure Néel-type domain wall profiles and skyrmion suppression below room temperature in magnetic [Pt/CoFeB/Ru]${}_{10}$ multilayers
• Time-resolved measurement of spin excitations in Cu${}_2$OSeO${}_3$
• Observation of distorted tilted conical phase at the surface of a bulk chiral magnet with resonant elastic x-ray scattering