Fig. 10

Spin-STM of thermally fluctuating magnetic order with a field-tuned superparamagnetic tip. a–d CC-STM (a) and dI/dV maps at 0 T (b), +1.5 T (c), and −1.5 T (d) of a bilayer bridge-stacked Fe nanoisland measured with a superparamagnetic Fe-coated W tip at 10 K. (V _b = − 0.5 V, I _set = 1 nA). e dI/dV profiles along the line depicted in the CC-STM image in a, measured at −1.5 T (black), −0.5 T (red), 0 (green), +0.5 T (blue), +1.5 T (cyan). f Field dependence of dI/dV contrast of the stripe pattern (red) measured at a bright center as marked by the cross in d. Field dependence of the dI/dV contrast measured at the center of the Co (blue) of the Fe|Co island as indicated in the inset, with the same tip as used for measuring the Fe island. The solid curves are fits of the data to the Langevin equation, for the Fe (red) and Fe|Co (blue) nanoislands. All the data are normalized with the saturation values obtained from the Langevin fits