Micromagnetic study of skyrmion racetrack and microwave oscillator

Skyrmions are topologically protected magnetic solitons which are attracting a lot of interest from either a fundamental or a technological point of view. Skyrmions can behave as static objects, being shifted in a racetrack memory or as dynamical solitons, giving rise to topological droplets. This paper points out that a Néel skyrmion based racetrack memory driven by the spin-Hall effect could be a competitive memory architecture, and that, in nano-contact geometry, the spin-transfer torque, together with the Dzyaloshinskii-Moriya interaction, can excite stationary and non-stationary topological droplets.