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

The potential of spin-polarized scanning tunneling microscopy and spectrosc opy (SP-STNVS) is demonstrated on three different classes of surfaces, name ly on antiferromagnetic and ferromagnetic transition metals and on rare-ear th metals. The data measured on the topological antiferromagnetic Cr(0 0 1) surface reveal that screw dislocations cause topology induced spin frustra tions leading to the formation of domain walls with a width of about 120 nm . On another antiferromagnetic surface a pseudomorphic monolayer film of ch emically identical manganese atoms on W(1 1 0), we could show that SP-STM e nables to measure the surface magnetic structure with atomic resolution. SP -STS also allows the imaging of the domain structure of self-organized Fe n anostructures which are anti ferromagnetically coupled due to dipolar inter action. It is shown that the special electronic structure of rare-earth met al (000 1)-surfaces, i.e. the existence of exchange-split surface states cl ose to the Fermi level, allows the spatially resolved mapping of a spin asy mmetry parameter which reduces tip-related properties. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.