ITINERANT ELECTRON SURFACE MAGNETISM

Although many experiments have been applied to study the surface magnetism, only a few give a direct and unambiguous answer to a so simple question as "what is the value of the surface magnetic moment". Some examples of all these experiments are reviewed to show the main differences between two- and three-dimensional magnetism. Then we show that the magnetic moment can be enhanced near the surface in itinerant electron magnetism. This may be the case of He-3 atoms in confined geometries, or of transition metal surfaces or more generally when the local surface density of states at the Fermi level is much larger than the bulk one.