Field and temperature dependence of the skyrmion lattice phase in chiral magnet membranes

DOI: 10.1103/PhysRevB.101.014446

Authors: David M. Burn (Diamond Light Source) , Shasha Wang (High Magnetic Field Laboratory, Chinese Academy of Sciences) , Weiwei Wang (Anhui University) , Gerrit Van Der Laan (Diamond Light Source) , Shilei Zhang (ShanghaiTech University) , Haifeng Du (High Magnetic Field Laboratory, Chinese Academy of Sciences) , Thorsten Hesjedal (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 101

State: Published (Approved)
Published: January 2020
Diamond Proposal Number(s): 20182 , 20437

Abstract: Magnetic skyrmions are nanosized magnetization whirls that exhibit topological robustness and nontrivial magnetoelectrical properties, such as emergent electromagnetism and intriguing spin dynamics in the microwave-frequency region. In chiral magnets, skyrmions are usually found at a pocket in the phase diagram in the vicinity of the ordering temperature, wherein they order in the form of a hexagonal skyrmion lattice (SkL). It is generally believed that this equilibrium SkL phase is a uniform, long-range-ordered magnetic structure with a well-defined lattice constant. Here, using high-resolution small-angle resonant elastic x-ray scattering, we study the field and temperature dependence of the skyrmion lattice in FeGe and Cu 2 OSeO 3 membranes. Indeed, Cu 2 OSeO 3 shows the expected rigid skyrmion lattice, known from bulk samples, that is unaffected by tuning field and temperature within the phase pocket. In stark contrast, the lattice constant and skyrmion size in FeGe membranes undergo a continuous evolution within the skyrmion phase pocket, whereby the lattice constant changes by up to 15% and the magnetic scattering intensity varies significantly. Using micromagnetic modeling, it is found that for FeGe the competing energy terms contributing to the formation of the skyrmion lattice fully explain this breathing behavior. In contrast, for Cu 2 OSeO 3 this stabilizing energy balance is less affected by the smaller field variation across the skyrmion pocket, leading to the observed rigid lattice structure.

Journal Keywords: Skyrmions; Micromagnetic modeling; Resonant elastic x-ray scattering

Diamond Keywords: Skyrmions

Subject Areas: Materials, Physics


Instruments: I10-Beamline for Advanced Dichroism

Added On: 13/02/2020 09:18

Discipline Tags:

Surfaces Quantum Materials Hard condensed matter - electronic properties Physics Magnetism Materials Science interfaces and thin films

Technical Tags:

Scattering Resonant Elastic X-ray Scattering (REXS)