Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.14: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
No Co ferromagnetism in Co doped ZnO — •Thomas Tietze1, Sebastian Brück1, Eberhard Goering1, Gisela Schütz1, Milan Gacic2, Gerhard Jakob2, Christian Herbort2, and Hermann Adrian2 — 1Max-Plank-Institute for Metal Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany — 2Institute of Physics, University of Mainz, Staudinger Weg 7, 55099 Mainz, Germany
Diluted magnetic semiconductors, doped with a few percent (<10%) of magnetic ions such as Co or Mn, have attracted recently enormous interest, due to the room temperature ferromagnetism observed in such systems. The original intention for doping is that localized magnetic moments couple with each other ferromagnetically via the semi conducting host material. We have investigated 5% Co doped ZnO prepared by pulsed laser deposition (PLD). X-ray magnetic circular dichroism provides element specific magnetic moments of Co, Zn an O. We have performed field and temperature dependent XMCD-measurements at the Co and Zn L2,3 edges and the O K edge. As expected, Zn does not contribute to the ferromagnetism, but Co exhibits only paramagnetic behavior at all temperatures and fields. But surprisingly we found magnetic polarization, related to a small orbital moment; at the O site, suspected to be responsible for room temperature ferromagnetism of ZnO.