Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 30: II-VI Halbleiter III

HL 30.5: Vortrag

Samstag, 5. März 2005, 16:00–16:15, TU P164

Room-temperature ferromagnetism in Mn-alloyed ZnO — •Heidemarie Schmidt¹, Mariana Diaconu¹, Holger Hochmuth¹, Michael Lorenz¹, Gabriele Benndorf¹, Daniel Spemann¹, Annette Setzer¹, Pablo Esquinazi¹, Andreas Pöppl¹, Holger von Wenckstern¹, Karl-Wilhelm Nielsen², Rudolf Gross², Herbert Schmid³, Werner Mader³, Gerald Wagner⁴, and Marius Grundmann¹ — ¹Universität Leipzig, Fakultät für Physik and Geowissenschaften, 04103 Leipzig, Germany — ²Walther-Meißner-Institut für Tieftemperaturforschung, 85748 Garching, Germany — ³Rheinische Friedrich-Wilhelm Universität Bonn, 53117 Bonn, Germany — ⁴Universität Leipzig, Institut für Mineralogie, Kristallographie und Materialwissenschaft, 04275 Leipzig, Germany

Following [1] we prepared textured, soft ferromagnetic Mn-alloyed ZnO thin films by pulsed laser deposition at low growth temperatures around 500^∘C and ambient oxygen partial pressures larger than 0.1 mbar for future spintronics applications. The homogeneity and intrinsic nature of magnetic domain formation can be probed by magnetic force microscopy. At 300 K the saturation magnetization and coercive field of optimized films amount to 0.013 emu/g and 234 Oe, respectively. Atomic force microscopy and SQUID measurements reveal that the grain size for large coercive fields in 1 µm thick Mn-alloyed ZnO films ranges between 130-160 nm. The existence of a critical grain size in textured ferromagnetic films can be explained on the basis of Brown’s micromagnetic model. [1] P. Sharma et al., Nature Materials 2, 673 (2003).