Fig. 4
From: Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes
(Reprinted from [25] with permission from American Institute of Physics (Copyright 2009))
Magnetic response of tips in spin-STM. a–c dI/dV magnetic hysteresis loops measured on bilayer Co islands, with 3 different tips as denoted at the top-left corner of each figure. The black arrows show the field sweep directions for data acquisition. The red and green arrows represent the magnetization directions of tip and sample, respectively, at field values for dI/dV signal saturation. For the loop in a, a fixed tip magnetization direction is expected, however, its direction cannot be decided and the two possibilities are shown. d, e Schematics for local magnetic moments (d) and magnetization hysteretic response (e) of a bilayer Co island on Cu(111). f–h Field response of the tip magnetization extracted from the dI/dV hysteresis loops shown in a–c, respectively, in regard to the magnetic response of the Co island described in e