Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Magnetic Semiconductors
MA 24.2: Vortrag
Mittwoch, 25. März 2009, 15:00–15:15, HSZ 401
Structural and Magnetic Properties of Gd doped ZnO — •Verena Ney1, Fabrice Wilhelm2, Tom Kammermeier1, Shuangli Ye1, Katharina Ollefs1, Andrei Rogalev2, and Andreas Ney1 — 1Experimentalphysik Universität Duisburg-Essen and CeNIDE, Lotharstr.1, D-47057 Duisburg, Germany — 2European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France
The hope of discovering a dilute magnetic semiconductor (DMS) with ferromagnetic order up to room temperature still motivates research on suitable material combinations. Approaches with Co doped ZnO have shown that films with high quality show a purely paramagnetic behaviour [1], which turns to be superparamagnetic as soon as clusterformation starts. The comparison of ion-implanted Co:ZnO with Gd:ZnO showed that Gd might be a better candidate [2]. Therefore Gd doped ZnO was prepared by reactive magnetron sputtering with high concentrations ranging from 1.4% to up to 16% of Gd in ZnO. X-ray diffraction and element specific x-ray linear dichroism (XLD) were used for the structural characterization. The corresponding magnetic properties were measured with SQUID magnetometry and - again element specific - with x-ray magnetic circular dichroism (XMCD). Due to the large Gd-atom, the structural quality of the films is reduced with increasing Gd-content. Nevertheless, in the entire doping range we find no sign of intrinsic ferromagnetic interaction for the homogeneous Gd doped ZnO system as well as no long range magnetic order.
[1] A. Ney et al, Phys. Rev. Lett. 100, 157201 (2008)
[2] V. Ney et al, J. Appl. Phys. 104, 083904 (2008)