Fig. 2
From: Inducing skyrmions in ultrathin Fe films by hydrogen exposure
SP-STM images of the two different H-Fe double-layer areas at different applied magnetic fields. a SP-STM constant-current image of the H-induced superstructures on the Fe-DL without external magnetic field B. The apex of the Cr bulk tip has its magnetic moment m t perpendicular to the surface, thus the tip is sensitive to the out-of-plane magnetization components of the sample. The periodic modulation of the contrasts for H1-Fe demonstrates spin spiral order, whereas the two-level contrast on H2-Fe reflects its ferromagnetic ground state. b Same as a but in a perpendicular magnetic field of B = 3 T. The dark dots and the surrounding brighter area in H1-Fe are magnetized in opposite out-of-plane directions. Both islands of H2-Fe now show the same magnetic contrast, i.e., they are magnetized along the same direction. c Same as a, also in zero-magnetic field. In this remanent state, the spin spiral in the H1-Fe area is more disordered and the H2-Fe islands remain in their field-polarized states. Measurement parameters: U = −0.7 V; I = 1 nA; T = 4.2 K. Scale bars 15 nm
