Extended Data Fig. 1: Telegraph noise in switching maps.
From: Experimental identification of two distinct skyrmion collapse mechanisms
a, Map of skyrmion collapse rate, B∥ = 1.5 T, B⊥ = 1.5 T, V = 610 mV, I = 60 nA, Δt = 150 s (same as Fig. 3f). Large (small) circle marks skyrmion area (hot spot of collapse rate). Colored rectangles with numbers mark positions, where time traces and histograms are displayed in (b), (c). b, Left: time trace (orange curve) on position marked as 1 in (a). The deduced digital values (blue, dashed curve) using a threshold (black, dashed line) are shown with upper (lower) value marking the ferromagnetic (skyrmion) state. The skyrmion probability PSK and the number of switching events n are marked on top. These numbers are used to calculate the collapse rate ratecollapse by the given formula for a time interval Δt of recording. Right: histograms of measured dI/dV values during the time trace. c, Time traces as exemplarily shown in (b) (left) and histograms of measured dI/dV values during the time trace (right) for the positions marked in (a) by the same number and frame color. Deduced rates for collapse and creation, skyrmion probability PSK and number of switching events n are marked on top in each frame. Frames are ordered for pixels within the skyrmion interior (left) and at the rim of the skyrmion (right). While the histograms from the interior are always bimodal, additonal peaks partly appear at the rim. They are likely caused by switching of neighboring skyrmions. (More time traces and detailed discussion: Supplementary Fig. S3).
