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 15.15: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Defect-induced Ferromagnetism in Co-doped ZnO Thin Films — •Gillian Mayer1, Erwin Biegger1, Mikhail Fonin1, Nils Janßen1, Markus Beyer1, Rudolf Bratschitsch1, Yury Dedkov2, and Ulrich Rüdiger1 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz — 2Institut für Festkörperphysik, Technische Universität Dresden, 01062 Dresden
Ferromagnetic diluted magnetic oxides (DMOs) have been the subject of intense research due to their possible application in spintronic devices. Much attention has been paid to transition metals doped wide band-gap semiconductors such as ZnO.
In this study, Co-doped ZnO films have been prepared in order to investigate the structural, magnetic, optical, and electronic properties of the DMO. Control over the oxygen vacancy concentration in the ZnO host lattice was achieved by using different preparation conditions. Magnetization measurements indicate weak ferromagnetism at low temperature only for the samples prepared at oxygen poor conditions. X-ray absorption spectroscopy (XAS) and optical transmittance measurements have been performed to identify the oxidation state as well as site symmetry of Co in the ZnO host lattice. Comparison of O K XAS spectra show oxygen vacancies related features in case of ferromagnetic Zn1−xCoxO samples. Our findings indicate that ferromagnetism of the Co-doped ZnO is strongly correlated to the presence of oxygen vacancies in the ZnO host lattice supporting the spin-split impurity band model [1].
[1] J.M.D. Coey et al., Nat. Mater. 4, 173 (2005)