Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 15: Functional Oxides

DS 15.1: Hauptvortrag

Dienstag, 26. Februar 2008, 14:30–15:00, H 2032

The truth about ferromagnetic ZnO — •Kay Potzger¹, Shengqiang Zhou¹, Georg Talut¹, Karsten Kuepper¹, Helfried Reuther¹, Arndt Mücklich¹, Jörg Grenzer¹, Manfred Helm¹, Jürgen Fassbender¹, Heidemarie Schmidt¹, Quingyu Xu¹, and Michael Lorenz² — ¹Forschungszentrum Dresden-Rossendorf, Bautzner Landstrasse 128, 01328 Dresden — ²Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig

The combination of magnetic and semiconducting properties in oxides is currently one of most popular fields in materials research. Besides the expected gain of knowledge about basic physics, such materials have a large application potential in spin electronics. We present a summary of our results on transition metal doping of ZnO single crystals and thin films by means of ion implantation. We found that none of the samples investigated represents a diluted magnetic semiconductor as predicted by theory [1]. Nevertheless, transition metal ions can be dispersed within the ZnO matrix residing on different sites within the lattice depending on initial preparation conditions. The observed ferromagnetism mainly originates from secondary phase formation (metals or inverted spinels). We discuss the potential of those granular structures in spin-electronics. Moreover, we highlight the suppression of secondary phase formation by means of deliberately lowering the crystalline quality prior to the doping. In that case, purely defect induced ferromagnetic properties are observed. The effect of spin doping of such a defect induced ferromagnet is discussed.

[1] K. Sato and H. Katayama-Yoshida, Physica E 10, 251 (2001).