Fig. 4: Transition from bubbles into biskyrmions.
From: Formation of magnetic biskyrmions mediated by an intrinsic emergent monopole-antimonopole pair
a Biskyrmions at the middle plane of a rectangle film. The sample is defined as 1 μm × 0.5 μm × 160 nm size with cells of 4 nm × 4 nm × 4 nm. The magnetic easy axis lies in yz-plane. b The dependence of the topological charge Q on the perpendicular position of the left biskyrmion in a during the process of removing Bz. c The variations of different energy terms ΔE during the process of removing Bz. The initial values at Bz = 0.14 T are subtracted from the energy terms for better illustration. EZ, EA, EX, and ED denote Zeeman, anisotropy, exchange, and magnetostatic energy, respectively. d, e The distribution of magnetostatic energy density eD on the contour surface with mz = 0 at Bz = 0.14 T and 0 T, respectively. Gray dots depict the location of the AMPs.
