Superlattices and Microstructures 39, 334 (2006)
E-MRS 2005 Symposium G: ZnO and Related Materials – Part 2

H. Schmidt, M. Diaconu, H. Hochmuth, M. Lorenz, A. Setzer, P. Esquinazi, A. Pöppl, D. Spemann, K.-W. Nielsen, R. Gross, G. Wagner and M. Grundmann

Abstract

Room-temperature ferromagnetic Zn_1−x(TM)_xO semiconductor thin films have been grown by pulsed laser deposition (PLD) on c-plane sapphire substrates and the effect of the substitution of Zn²⁺ ions by transition metal ions (Mn²⁺ or Ti²⁺) has been investigated. In contrast to ZnTiO thin films, the grain size of the ZnMnO thin films can be controlled in a wide range by the PLD growth conditions. The magnetic properties of the Zn_1−x(TM)_xO films have been investigated by a superconducting quantum interference device (SQUID). For semi-insulating ZnMnO films with an optimized grain size, we observed a weak ferromagnetism for temperatures up to 400 K [M. Diaconu, H. Schmidt, H. Hochmuth, M. Lorenz, G. Benndorf, J. Lenzner, D. Spemann, A. Setzer, K.-W. Nielsen, P. Esquinazi, M. Grundmann, Thin Solid Films 486 (2005) 117–121], while the ZnTiO films were only paramagnetic or superparamagnetic. This is expected with respect to the micromagnetic model.