Magnetic skyrmions can be considered as topologically protected localizedvortex-like spin textures. Due to their stability, their small size, and thepossibility to move them by low electric currents they are promising candidatesfor spintronic devices. Without violating topological protection, it ispossible to create skyrmion-antiskyrmion pairs, as long as the total chargeremains unchanged. We derive a skyrmion equation of motion which reveals howspin-polarized charge currents create skyrmion-antiskyrmion pairs. It allows toidentify general prerequisites for the pair creation process. We corroboratethese general principles by numerical simulations. On a lattice, wheretopological protection becomes imperfect, the antiskyrmion partner of the pairsis annihilated and only the skyrmion survives. This eventually changes thetotal skyrmion number and yields a new way of creating and controllingskyrmions.
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