Hamburg 2001 – wissenschaftliches Programm

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O: Oberflächenphysik

O 25: Postersitzung (Grenzfl
äche fest-flüssig, Methodisches, Nanostrukturen, Organische Dünnschichten, Rastersondentechniken, reine Oberfl
ächen, Teilchen und Cluster, Zeitaufgelöste Spektroskopie, Sonstiges)

O 25.84: Poster

Mittwoch, 28. März 2001, 15:00–18:00, Foyer zu B

Absence of ferromagnic order in Gd(0001) surface oxide — •Oleg Krupin¹, Serguej Gorovikov^1,2, Günter Kaindl¹ und Kai Starke¹ — ¹Fachbereich Physik, Freie Universität Berlin, Germany — ²Maxlab, Lund, Sweden

It has been shown recently that oxygen adsorption on Gd(0001) leads to the formation of an epitaxial surface monoxide [1]. No suppression of long-range 4f-spin order was found in this surface oxide phase, but rather a temperature dependent valence-state exchange splitting that remains finite above the bulk Curie temperature.

Here we report on an MDPE study (Magnetic Dichroism in Core-Level Photoemission [2]) employing an unpolarized He-II laboratory source. A clear magnetic dichroism signal was observed for the bulk component of the Gd 4f-photoemission line, indicating ferromagnetic spin order of the sub-surface atomic layers. Yet the chemically shifted surface-oxide 4f component reveales no dichroic signal. Based on this finding, models of possible long-range spin order of the surface oxide are discussed.


This work has been supported by the Deutsche Forschungsgemeinschaft (Sfb 290, TP A6).

[1] C. Schüßler-Langeheine et al., Phys. Rev. B 60, 3449 (1999)

[2] K. Starke, Magnetic Dichroism in Core-Level Photoemission, (Springer, Berlin, Heidelberg, 2000)