Recent highlights of X-ray magnetic scattering studies from surfaces

In this work, recent studies of surface magnetism, as observed by x-ray sca ttering techniques, are described. The experiments were concerned with uran ium dioxide crystals for which x-ray resonance effects enhance the small ma gnetic signal from the surface. The main result is that, in contrast to the bulk which exhibits a discontinuous magnetic ordering transition, both the (001) and (111) surface layers order continuously. This is reminiscent of the general phenomenon of surface wetting, but had not been previously obse rved for magnetic materials. Magnetic reflectivity studies show further tha t the near-surface magnetic layers are more disordered than layers deep in the bulk, even at low temperatures.