Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Magnetic Coupling Phenomena/ Exchange Bias

MA 33.2: Talk

Wednesday, March 28, 2012, 15:30–15:45, EB 202

XMCD-XRMR studies of Exchange Bias Systems — •Patrick Audehm¹, Mathias Schmidt¹, Sebastian Macke², Gisela Schütz¹, and Eberhard Goering¹ — ¹Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany — ²The University of British Columbia, 2329 West Mall, Vancouver, Canada

Since the discovery of the exchange bias (EB) in 1956 by Meiklejohn and Bean, the effect in all its varieties is not completely understood. We investigated a widely studied EB-system of polycrystalline Co on FeMn. The sputtered samples are investigated with a broad range of different techniques, like as X-ray magnetic circular dichroism (XMCD) and x-ray resonant magnetic reflectivity (XRMR) at the L2,3 edges of the transition metals, simultaneously performed in surface sensitive total electron yield (TEY) and bulk sensitive total fluorescence yield (TFY), all at room and low temperatures. With our state of the art soft-X-ray reflectometer we are able to identify element specifically even smallest amounts of magnetic moment contributions via magnetic reflectivity asymmetry and sum rules. Additionally we are measuring the energy dependent reflection with constant momentum transfer which is the direct combination of XMCD and XRMR. With all these techniques we found uncompensated, non-rotatable magnetic moments in iron. All these moments are located at the interface to the Co-layer. Our results lead to a better understanding of the micro magnetic understanding of the EB.