Nano- and atomic-scale magnetism studied by spin-polarized scanning tunneling microscopy and spectroscopy

The potential of spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM/S) is demonstrated on three different classes of surfaces, namely on antiferromagnetic and ferromagnetic transition metals and on rare-earth metals. The data measured on the topological antiferromagnetic Cr(001) surface reveal that screw dislocations cause topology induced spin frustrations leading to the formation of domain walls with a width of about 120 nm. On another antiferromagnetic surface a pseudomorphic monolayer film of chemically identical manganese atoms on W(110), we could show that SP-STM enables to measure the surface magnetic structure with atomic resolution. SP-STS also allows the imaging of the domain structure of self-organized Fe nanostructures which are antiferromagnetically coupled due to dipolar interaction. It is shown that the special electronic structure of rare-earth metal (0001)-surfaces, i.e. the existence of exchange-split surface states close to the Fermi level, allows the spatially resolved mapping of a spin asymmetry parameter which reduces tip-related properties.