RECENT DEVELOPMENTS IN SURFACE AND THIN-FILM MAGNETISM PROBED BY SPIN-POLARIZED ELECTRONS

Experiments using spin-polarized low-energy electrons provide direct a ccess to surface magnetic properties by separately probing the exchang e-split majority and minority electronic states to an information dept h of just a few atomic layers. This is demonstrated by results from tw o types of experiments. (i) Magnetometry with secondary electrons give s information on the magnetization as a function of the field and temp erature as well as on the exchange coupling at a ferromagnetic surface or between ultrathin magnetic films. (ii) Spin- and angular-resolved inverse photoemission allows detailed study of the spin-dependent empt y electronic structure, thereby complementing information gained by ph otoemission on the occupied states. Results on energy versus momentum dispersion, exchange splitting of bulk and surface states, and adsorba te-induced changes of the spin-dependent electronic structure contribu te to a microscopic picture of ferromagnetism at surfaces. The spin de pendence of interface states is important for understanding magnetic c oupling phenomena in thin film structures.