Additional figures : FIG. 6: SEMPA images of circular 15 nm thick NiFe nanodots with different diameters d = 72, 125, 200 and 500 nm. For d = 72 nm, the remanent magnetic state is a single-domain state for all the nanodots. By increasing the diameter to d = 125 nm, a few dots remain in single domain state whereas for most of them, the direction of the magnetic moments is changing gradually in-plane leading to a changing contrast between black and white. For larger diameters, the most favorable configuration is eventually a single vortex state, in particular for the diameter of d = 170 nm chosen for the rest of the study. 13