Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)
MA 18.14: Poster
Dienstag, 26. Februar 2008, 15:15–18:30, Poster E
XMCD study of doped ZnO and Si magnetic semiconductors — •Thomas Tietze1, Sebastian Brück1, Saroj Dash1, Eberhard Goering1, Milan Gacic2, Gerhard Jakob2, Christian Herbort2, and Hermann Adrian2 — 1Max-Planck-Institue for Metal Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany — 2Institute of Physics, University of Mainz, Staudinger Weg 7, 55099 Mainz, Germany
Diluted magnetic semiconductors (DMS) doped with a few percent (<10%) of magnetic ions, as Co or Mn, have shown room temperature ferromagnetism transforming these to a promising candidate for spintronic devices. Previously, we have unexpectedly found pure paramagnetic behavior of the magnetic ion dopants. Additional Li doping has been used to enhance the ferromagnetic signature of the DMS. Therefore, we have investigated ZnO doped with 5% Co and co-doped with 10% Li thin films and pure Si doped with 5 % implanted Mn. Clear ferromagnetic room temperature properties have been found by SQUID magnetometry. In order to identify the element which is responsible for the ferromagnetic moment, we have performed X-ray Magnetic Circular Dichroism studies at the TM and Si L2,3 edges and the O K edge. We found only a paramagnetic XMCD-signal on the Co and Mn L2,3-edges. With a very high signal to noise ratio of better than 1/10000 we did not find any significant XMCD effect on neither the Si L2,3 nor the O K-edges. In order to clearly probe bulk properties, we have also investigated the resonant magnetic responses in reflection geometry and TFY mode, but no ferromagnetic signature has been found.