Fig. 3: Skyrmion braids in an extended FeGe plate of thickness 180 nm.
From: Magnetic skyrmion braids
a–c Experimental Lorentz TEM images of twisted skyrmions–skyrmion braids (upper row) and untwisted (lower row) skyrmions recorded at two different magnetic fields in sample S1 at 95 K. d–g Theoretical results for Bext = 275 mT, assuming periodic boundary conditions in the xy plane and free surfaces in the third dimension. From left to right, each row shows: an equilibrium state represented by isosurfaces of mz = 0; in-plane magnetization \({\langle {{{{{{{{\bf{m}}}}}}}}}_{{{{{{{{\rm{xy}}}}}}}}}\rangle }_{{{{{{{{\rm{z}}}}}}}}}\) averaged over the thickness of the plate; underfocus and overfocus Lorentz TEM images; electron optical-phase image. The index at the top-right corner in a–c and in the simulated images of \({\langle {{{{{{{{\bf{m}}}}}}}}}_{{{{{{{{\rm{xy}}}}}}}}}\rangle }_{{{{{{{{\rm{z}}}}}}}}}\) indicates the number of skyrmion strings Nsk in the braid. An isolated skyrmion string is shown in d for comparison with skyrmion braids in e–g.
