Berlin 2008 – wissenschaftliches Programm

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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

Freitag, 29. Februar 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 L_2,3 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).