The development of spinÃ¢â¬Âpolarized spectroscopy techniques offers some of the most powerful probes to study the magnetic phenomena related to the interface region of free magnetic surfaces and multilayer systems. The study of the magnetic properties of surfaces and interfaces is relevant in the basic understanding of, e.g., the coupling in magnetic multilayer systems. By spinÃ¢â¬Âpolarized lowÃ¢â¬Âenergy electron diffraction it has been possible to characterize such magnetic interfaces allowing to test the validity of recent theoretical models. Thus, depending on the strength of the surface magnetic coupling, different magnetic phase transitions can occur, the most spectacular one being the case when at the surface the ferromagnetic to paramagnetic transition occurs at a higher temperature than in the bulk. This phenomenon has indeed been demonstrated on Gr(0001)1 and on Tb surfaces.2 Furthermore, indications of anomalous behavior on Gd/3 leads now to consider an interpretation in the frame of the firstÃ¢â¬Âorder phase transition predicted recently.4 The role of the interface region in the coupling between epitaxial ferromagnetic layers separated by an antiferromagnetic material has also been studied.5 Two Fe(001) films separated by a thin slab of Cr exhibit antiparallel coupling. The Cr(001) slab, however, shows no indications of the expected ferromagnetic surface sheet configuration. © 1988, American Institute of Physics. All rights reserved.