We report on the use of recently developed spin-polarized electron sources with very high polarization for electron spectroscopy. In particular we present data of spin-resolved inverse photoemission from Fe(100) films excited by polarized electrons produced by a strained GaAsP negative electron affinity photocathode. This highly polarized source (beam polarizationP=65&percent;) allows a direct and almost complete decoupling of the majority and minority empty states in Fe(100), much better than the standard GaAs sources (P=20&percent;–30&percent;). The preparation and characterization of the strained photocathode is also discussed. ©1997 American Institute of Physics.