Creating arbitrary sequences of mobile magnetic skyrmions and antiskyrmions

Magnetic skyrmions and their anti-particles, the antiskyrmions, are stable\nmagnetic solitons existing down to the nanometer scale. Their stability and\nsize as well as the possibility to propel them by, e.g., electric currents make\nthem promising candidates for the use in memory devices, such as racetrack\nmemories. Skyrmions and antiskyrmions share those same advantages individually,\nbut may annihilate each other when they coexist in the same device. Yet,\ncombining them to represent logical bits of 0 (skyrmion) and 1 (antiskyrmion)\nin one device opens new possibilities to create new types of densely packed\nracetrack memory devices. For this, a controlled creation and annihilation\nprocedure, i.e., a writing or deletion operation, is necessary. Here, we\npropose a method to create arbitrary sequences of coexisting skyrmions and\nantiskyrmions by rotations of the magnetic moments at the edge of a rectangular\nslab. The skyrmions and antiskyrmions remain stable and do not annihilate each\nother.\n