Münster 1997 – scientific programme

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AM: Magnetismus

AM 20: Spektroskopie, Dichroismus III

AM 20.7: Talk

Thursday, March 20, 1997, 12:15–12:30, F5

Magnetic Dichroism in Photoemission with Unpolarized Light from the 2p Core Levels of Ultrathin Co films — •M. Salvietti, X.Y. Gao, W. Kuch, C.M. Schneider, and J. Kirschner — Max-Planck-Institut f"ur Mikrostrukturphysik, Weinberg 2, D-06120 Halle

We have investigated the angular dependence of the magnetic dichroism in angle-resolved photoemission from the 2p core levels of epitaxial ultrathin Co films grown on Cu(100) using unpolarized MgK_α radiation (MDAD). The dichroism occurs by reversing the sample magnetization along the normal to the plane defined by the photon and photoelectron wavevectors. The Energy Distribution Curves of the photoelectrons were collected for different emission angles around the surface normal. A simple method is used to extract from the resulting dichroic asymmetry at each emission angle the component due to the photoelectron diffraction. We have analyzed this component for a Co thickness from 5 ML to 1.5 ML and a temperature of the film of 120 K and 300 K. It was found that at 5 ML the diffraction effect is affected by the temperature and at 1.5 ML is negligible. The resulting magnetic dichroism in the absence of the diffraction effect is analyzed in terms of the atomic model. In particular we observe that at lower thicknesses the multiplet structures present in the dichroic asymmetry become less prominent, suggesting an interplay between many-body interactions and electronic hybridization with the substrate.