Berlin 2008 – scientific programme
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MA: Fachverband Magnetismus
MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)
MA 32.16: Poster
Friday, February 29, 2008, 11:15–14:00, Poster E
Structural and magnetic properties of Co– and Mn–doped ZnO thin films — •Gillian Mayer1, Sönke Voss1, Mikhail Fonin1, Ulrich Rüdiger1, Reinhard Schneider2, Dagmar Gerthsen2, and Eberhard Goering3 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz — 2Laboratorium für Elektronenmikroskopie, Universität Karlsruhe, 76128 Karlsruhe — 3Max Planck–Institut für Metallforschung, 70569 Stuttgart
Diluted magnetic oxides have attracted much attention because of their possible application in spintronic devices. Especially d–metal doped ZnO is a promising candidate as proposed by Dietl et al. [1]. Structural and magnetic properties of Co– and Mn–doped ZnO thin films prepared by rf magnetron sputtering from composite Zn/Co and Zn/Mn targets have been studied. X–ray absorption measurements at the Co and Mn L2,3 absorption edges indicate that Co2+ and Mn2+ are incorporated at Zn sites in ZnO. In SQUID investigations, as prepared Co–doped samples show pure paramagnetism, while vaccum–annealed samples and some of the Mn–doped samples show a ferromagnetic behavior. A detailed X–ray magnetic circular dichroism study of Co–doped ZnO at different temperatures reveales that Co contributes only paramagnetically to the magnetism in vacuum–annealed samples. Transmission electron microscopy investigation of Co–doped ZnO shows that postannealing of the samples leads to the formation of Co–rich clusters that however do not contribute to ferromagnetism. The possible contribution of the substrate to the ferromagnetic behavior is also discussed. [1] Dietl et al., Science 287, 1019 (2000).