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MA: Fachverband Magnetismus

MA 9: Surface Magnetism II

MA 9.3: Vortrag

Montag, 23. März 2009, 15:45–16:00, HSZ 403

Magnetic circular dichroism in two-photon photoemission from Co/Cu(001) — •Cheng-Tien Chiang, Aimo Winkelmann, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle(Saale), Germany

Magnetic circular dichroism in photoemission is an important tool in magnetic imaging and investigation of electronic structure of magnetic materials. Using ultrashort laser pulses for excitation, we observe magnetic circular dichroism in two-photon photoemission from Co/Cu(001) at 3.1 eV incident photon energy. The thickness dependence of the dichroic signal of photoemission from near the Fermi level shows a monotonic increase up to 12 ML and then reaches a saturation value of about 10%. For the 12 ML film, the dichroic signal decreases from 10% for photoelectrons from the Fermi level to 2% at 0.7 eV below the Fermi level. We compare our observation with studies employing one-photon photoemission near threshold and to measurements using VUV synchrotron radiation, where significantly smaller intensity asymmetry of 0.5% [1] and 4% [2] are obtained.

[1] T. Nakagawa and T. Yokoyama, Phys. Rev. Lett. 96, 237402 (2006) [2] C. M. Schneider et al., Phys. Rev. B 44, 12066 (1991)