Figure 9

X-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements. Schematic setup for simultaneous detection of total-electron yield (TEY) and luminescence yield (LY) in the vacuum chamber of the magnet. In TEY, the drain current (compensation current) is a measure for the amount of emitted electron due to x-ray absorption. TEY is surface-sensitive. In LY, which probes the entire thin-film sample, the transmitted x-rays that are not absorbed in the sample stack give rise to x-ray excited optical luminescence in the sapphire substrate. The emitted optical photons exit through a hole in the back of the sample holder and are detected by a photodiode.