Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 30: Magnetische dünne Schichten III
MA 30.1: Vortrag
Freitag, 12. März 2004, 10:45–11:00, H10
A XMCD study of GdN thin films and GdN/Fe Multilayers — •Frank Leuenberger1, Anne Parge1, Kai Fauth2, François Baudelet3, Christine Giorgetti3, Thomas Neisius4, Olivier Mathon4 und Wolfgang Felsch1 — 1I. Physikalisches Institut Göttingen, Bunsenstr. 9, 37073 Göttingen — 2Experimentelle Physik IV, Universität Würzburg — 3LURE, Centre Universitaire Paris-Sud, France — 4ESRF, BP 220, F-38043 Grenoble Cedex, France
In contrast to most rare-earth pnictides that are semimetals, there is an uncertainty about the ferromagnet GdN. Recent calculations predict GdN to be a semiconductor with a narrow indirect gap of 0.8eV [1], but it is not clear if the gap closes below TC (∼60K) leading to a half- or semimetal. The ferromagnetic exchange in GdN via 4f-5d-4f as well as the antiferromagnetic via 5d-2p-5d is shown here by measureing the Gd L2,3-, Gd M4,5- and the N K- edge dichroic signal. In case of the N-K dichroism a preliminary LSDA+U calculation from H. Ebert an coworkers shows a rough consistence with the measured signal, but can not explain the whole singal. In GdN/Fe multilayers XMCD is the ideal method to extract magnetic effects at the interface. Measurements of the dichroism at the L and M edges of Gd show that the Fe induces magnetic order on the Gd-5d and 4f states above TC(GdN) on a length scale of a few Å near the interfaces by strong 3d-5d hybridization.
[1] W. R. L. Lambrecht, Phys. Rev. B, 62, 13538 (2000)
[2] R. E. Camley, Phys. Rev. B, 39, 12316 (1989)