Fig. 7
From: Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes
(Reprinted from [7] with permission from Nature Publishing Group (Copyright 2014))
Stoner-Wohlfarth response of spin-STM tip. a A STM image showing a Fe|Co island and Fe island (V b = −0.3 V, I set = 3 nA). The black dashed curve encloses the Co core. b and c Magnetic hysteresis loops of dI/dV signals (V b = −0.75 V) of the STS spectra measured at the center (marked by the cross) of the Co core of the island A (field sweep between −3 T and +3 T for b; field sweep between −1 T and +1 T for c). Red (blue) color code denotes the dI/dV values measured for the forward (backward) field sweep. The purple and green arrows indicate the directions of the magnetizations of the tip and Co core, respectively. Note that the Co magnetization M Co retains its orientation in c. The dashed curves in c are fits according to the SW model of the data with as a fit parameter. The solid (dashed) red arrows indicate the magnetization switching of the tip (the SW-magnet). d Description of the tip magnetization vector M T based on a SW model. α and θ represent the polar angles of the magnetic easy axis and the magnetization vector, respectively, with respect to the direction of the external magnetic field (along the z-axis)