Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.105: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Co-doped zinc oxide — •M. Lübbe¹, K.-W. Nielsen¹, A. Erb¹, J. Simon², W. Mader², L. Alff¹, M. Opel¹, and R. Gross¹ — ¹Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching — ²Institut für Anorganische Chemie, Rheinische Friedrich-Wilhelm Universität, D-53117 Bonn

Due to their potential application in spintronics diluted magnetic semiconductors have attracted much interest. In particular, thin films of ZnO with a few atomic percent of a transition element substituted for zinc are studied intensively. Recently, a model based on a narrow impurity band [1] has been proposed for explaining the ferromagnetic exchange in ZnO. According to this model, Zn_1−xCo_xO is expected to show ferromagnetism at room temperature and hence has attracted broad interest.

We have prepared quasi-homoepitaxial Zn_0.95Co_0.05O and Mn_0.95Co_0.05O films on ZnO substrates by UHV pulsed laser deposition with substrate temperatures ranging between room temperature and 600^∘C and different background atmospheres (Ar or Ar + 1% O₂). During growth the thin films are characterized by in-situ RHEED. Furthermore X-ray diffraction and reflectometry as well as transmission electron microscopy have been applied for structural characterization. The magnetic properties have been analyzed by SQUID magnetometry and magnetotransport experiments. The Co substituted samples show ferromagnetic hysteresis at room temperature and a saturation magnetization of up to 1µ_B/Co.
This work is supported by the DFG via SPP 1157.
M. Venkatesan et al., Phys. Rev. Lett. 93, 177206 (2004)