  We report the direct evidence of field-dependent character of the interaction
between individual magnetic skyrmions as well as between skyrmions and edges in
B20-type FeGe nanostripes observed by means of high resolution Lorentz
transmission electron microscopy. It is shown that above certain critical
values of external magnetic field the character of such long-range skyrmion
interactions change from attraction to repulsion. Experimentally measured
equilibrium inter-skyrmion and skrymion-edge distances as function of applied
magnetic field shows quantitative agreement with the results of micromagnetic
simulations. Important role of demagnetizing fields and internal symmetry of
three-dimensional magnetic skyrmions are discussed in details.
