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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 15.13: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

X-ray magnetic circulardichroism in cobalt-doped ZnO — •Karl-Wilhelm Nielsen¹, Sebastian Bauer¹, Konrad Senn¹, Sebastian T. B. Goennenwein¹, Matthias Opel¹, Júlio Cezar², Dieter Schmeisser³, and Rudolf Gross¹ — ¹Walther-Meissner-Institut, Bayerische Akademieder Wissenschaften, Garching, Germany — ²EuropeanSynchrotron Radiation Facility, Grenoble Cedex, France — ³Brandenburgische Technische Universität,Cottbus, Germany

Cobalt-doped ZnO is a diluted magnetic semiconductor with a reported Curie-temperature well above 300 K. Nevertheless, the origin of the ferromagnetic exchange still is under debate. To clearify this issue we have investigated cobalt-doped ZnO thin films with x-ray magnetic circular dichroism (XMCD). The (0001)-oriented Zn_0.95Co_0.05O thin films were grown on (0001) ZnO, (0001) Al₂O₃, and (0001) ScAlMgO₄ substrates by pulsed laser deposition. The magnetic properties were measured by SQUID magnetometry and XMCD. Room temperature magnetization measurements by SQUID magnetometry and XMCD in the fluorescence yield mode reveal ferromagnetic behavior with similar shape of the magnetization curves, however, with different absolute values. XMCD magnetization in total electron yield, which is surface sensitive, show only small magnetic moments, most likely due to a magnetically dead surface layer.

This work is supported by the DFG via SPP1157.