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.