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

Using high-resolution small-angle resonant elastic x-ray scattering, the authors study here the field and temperature dependence of the skyrmion lattice in FeGe membranes. In stark contrast to Cu${}₂$OSeO${}₃$, the lattice constant and skyrmion size undergo a continuous evolution within the skyrmion phase pocket, whereby the lattice constant changes by up to 15%. Micromagnetic modeling shows that the competing energy terms contributing to the formation of the skyrmion lattice fully explain the observed breathing behavior.