Fig. 4.

Magnetic field dependency of skyrmion radius. Dependency of the skyrmion radius with the magnetic field—Green dots correspond to to radius extracted from Monte Carlo simulations—Red dots are extracted from experiments realized with a bare tungsten tip—inset red frame: two example of the experimental dI/dU map used to extract this profile showing a single skyrmion through the TAMR effect—the left one was recorded at 120 mT—the right one at 190 mT (60 × 60 nm, I = 1 nA, U = −220 mV, ΔU_rms = 50 mV)—inset green frame: Theoretical dI/dU TAMR contrast of an isolated skyrmion at 300 mT, scale bar is 20 nm