X-RAY MAGNETIC CIRCULAR-DICHROISM INVOLVING VALENCE STATES

Magnetic circular dichroism in X-ray fluorescence is a probe of the sp in polarization of the occupied electron states. It can be measured un der resonant excitation conditions, i.e., by promoting an electron fro m a spin-orbit split core-level to the spin-polarized empty states, or by nonresonant excitation from such a core-level to continuum states. It is argued that the latter method is more readily interpreted and, at least as far as itinerant magnetism is concerned, provides valuable information concerning the spin imbalance of the valence band as a fu nction of energy and with element selectivity. Experimental techniques and limitations are also discussed.